diff options
Diffstat (limited to 'Documentation')
60 files changed, 3097 insertions, 1536 deletions
diff --git a/Documentation/ABI/testing/devlink-resource-mlxsw b/Documentation/ABI/testing/devlink-resource-mlxsw new file mode 100644 index 000000000000..259ed2948ec0 --- /dev/null +++ b/Documentation/ABI/testing/devlink-resource-mlxsw @@ -0,0 +1,33 @@ +What: /kvd/ +Date: 08-Jan-2018 +KernelVersion: v4.16 +Contact: mlxsw@mellanox.com +Description: The main database in the Spectrum device is a centralized + KVD database used for many of the tables used to configure + the chip including L2 FDB, L3 LPM, ECMP and more. The KVD + is divided into two sections, the first is hash-based table + and the second is a linear access table. The division + between the linear and hash-based sections is static and + require reload before the changes take effect. + +What: /kvd/linear +Date: 08-Jan-2018 +KernelVersion: v4.16 +Contact: mlxsw@mellanox.com +Description: The linear section of the KVD is managed by software as a + flat memory accessed using an index. + +What: /kvd/hash_single +Date: 08-Jan-2018 +KernelVersion: v4.16 +Contact: mlxsw@mellanox.com +Description: The hash based section of the KVD is managed by the switch + device. Used in case the key size is smaller or equal to + 64bit. + +What: /kvd/hash_double +Date: 08-Jan-2018 +KernelVersion: v4.16 +Contact: mlxsw@mellanox.com +Description: The hash based section of the KVD is managed by the switch + device. Used in case the key is larger than 64 bit. diff --git a/Documentation/ABI/testing/evm b/Documentation/ABI/testing/evm index 9578247e1792..d12cb2eae9ee 100644 --- a/Documentation/ABI/testing/evm +++ b/Documentation/ABI/testing/evm @@ -14,30 +14,46 @@ Description: generated either locally or remotely using an asymmetric key. These keys are loaded onto root's keyring using keyctl, and EVM is then enabled by - echoing a value to <securityfs>/evm: + echoing a value to <securityfs>/evm made up of the + following bits: - 1: enable HMAC validation and creation - 2: enable digital signature validation - 3: enable HMAC and digital signature validation and HMAC - creation + Bit Effect + 0 Enable HMAC validation and creation + 1 Enable digital signature validation + 2 Permit modification of EVM-protected metadata at + runtime. Not supported if HMAC validation and + creation is enabled. + 31 Disable further runtime modification of EVM policy - Further writes will be blocked if HMAC support is enabled or - if bit 32 is set: + For example: - echo 0x80000002 ><securityfs>/evm + echo 1 ><securityfs>/evm - will enable digital signature validation and block - further writes to <securityfs>/evm. + will enable HMAC validation and creation - Until this is done, EVM can not create or validate the - 'security.evm' xattr, but returns INTEGRITY_UNKNOWN. - Loading keys and signaling EVM should be done as early - as possible. Normally this is done in the initramfs, - which has already been measured as part of the trusted - boot. For more information on creating and loading - existing trusted/encrypted keys, refer to: + echo 0x80000003 ><securityfs>/evm - Documentation/security/keys/trusted-encrypted.rst. Both dracut - (via 97masterkey and 98integrity) and systemd (via + will enable HMAC and digital signature validation and + HMAC creation and disable all further modification of policy. + + echo 0x80000006 ><securityfs>/evm + + will enable digital signature validation, permit + modification of EVM-protected metadata and + disable all further modification of policy + + Note that once a key has been loaded, it will no longer be + possible to enable metadata modification. + + Until key loading has been signaled EVM can not create + or validate the 'security.evm' xattr, but returns + INTEGRITY_UNKNOWN. Loading keys and signaling EVM + should be done as early as possible. Normally this is + done in the initramfs, which has already been measured + as part of the trusted boot. For more information on + creating and loading existing trusted/encrypted keys, + refer to: + Documentation/security/keys/trusted-encrypted.rst. Both + dracut (via 97masterkey and 98integrity) and systemd (via core/ima-setup) have support for loading keys at boot time. diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index e76432b9954d..2028f2d093b2 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -17,7 +17,8 @@ Description: rule format: action [condition ...] - action: measure | dont_measure | appraise | dont_appraise | audit + action: measure | dont_measure | appraise | dont_appraise | + audit | hash | dont_hash condition:= base | lsm [option] base: [[func=] [mask=] [fsmagic=] [fsuuid=] [uid=] [euid=] [fowner=]] diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-netdev b/Documentation/ABI/testing/sysfs-class-led-trigger-netdev new file mode 100644 index 000000000000..451af6d6768c --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-netdev @@ -0,0 +1,45 @@ +What: /sys/class/leds/<led>/device_name +Date: Dec 2017 +KernelVersion: 4.16 +Contact: linux-leds@vger.kernel.org +Description: + Specifies the network device name to monitor. + +What: /sys/class/leds/<led>/interval +Date: Dec 2017 +KernelVersion: 4.16 +Contact: linux-leds@vger.kernel.org +Description: + Specifies the duration of the LED blink in milliseconds. + Defaults to 50 ms. + +What: /sys/class/leds/<led>/link +Date: Dec 2017 +KernelVersion: 4.16 +Contact: linux-leds@vger.kernel.org +Description: + Signal the link state of the named network device. + If set to 0 (default), the LED's normal state is off. + If set to 1, the LED's normal state reflects the link state + of the named network device. + Setting this value also immediately changes the LED state. + +What: /sys/class/leds/<led>/tx +Date: Dec 2017 +KernelVersion: 4.16 +Contact: linux-leds@vger.kernel.org +Description: + Signal transmission of data on the named network device. + If set to 0 (default), the LED will not blink on transmission. + If set to 1, the LED will blink for the milliseconds specified + in interval to signal transmission. + +What: /sys/class/leds/<led>/rx +Date: Dec 2017 +KernelVersion: 4.16 +Contact: linux-leds@vger.kernel.org +Description: + Signal reception of data on the named network device. + If set to 0 (default), the LED will not blink on reception. + If set to 1, the LED will blink for the milliseconds specified + in interval to signal reception. diff --git a/Documentation/ABI/testing/sysfs-class-net b/Documentation/ABI/testing/sysfs-class-net index 6856da99b6f7..2f1788111cd9 100644 --- a/Documentation/ABI/testing/sysfs-class-net +++ b/Documentation/ABI/testing/sysfs-class-net @@ -259,3 +259,27 @@ Contact: netdev@vger.kernel.org Description: Symbolic link to the PHY device this network device is attached to. + +What: /sys/class/net/<iface>/carrier_changes +Date: Mar 2014 +KernelVersion: 3.15 +Contact: netdev@vger.kernel.org +Description: + 32-bit unsigned integer counting the number of times the link has + seen a change from UP to DOWN and vice versa + +What: /sys/class/net/<iface>/carrier_up_count +Date: Jan 2018 +KernelVersion: 4.16 +Contact: netdev@vger.kernel.org +Description: + 32-bit unsigned integer counting the number of times the link has + been up + +What: /sys/class/net/<iface>/carrier_down_count +Date: Jan 2018 +KernelVersion: 4.16 +Contact: netdev@vger.kernel.org +Description: + 32-bit unsigned integer counting the number of times the link has + been down diff --git a/Documentation/ABI/testing/sysfs-kernel-livepatch b/Documentation/ABI/testing/sysfs-kernel-livepatch index d5d39748382f..dac7e1e62a8b 100644 --- a/Documentation/ABI/testing/sysfs-kernel-livepatch +++ b/Documentation/ABI/testing/sysfs-kernel-livepatch @@ -33,6 +33,32 @@ Description: An attribute which indicates whether the patch is currently in transition. +What: /sys/kernel/livepatch/<patch>/signal +Date: Nov 2017 +KernelVersion: 4.15.0 +Contact: live-patching@vger.kernel.org +Description: + A writable attribute that allows administrator to affect the + course of an existing transition. Writing 1 sends a fake + signal to all remaining blocking tasks. The fake signal + means that no proper signal is delivered (there is no data in + signal pending structures). Tasks are interrupted or woken up, + and forced to change their patched state. + +What: /sys/kernel/livepatch/<patch>/force +Date: Nov 2017 +KernelVersion: 4.15.0 +Contact: live-patching@vger.kernel.org +Description: + A writable attribute that allows administrator to affect the + course of an existing transition. Writing 1 clears + TIF_PATCH_PENDING flag of all tasks and thus forces the tasks to + the patched or unpatched state. Administrator should not + use this feature without a clearance from a patch + distributor. Removal (rmmod) of patch modules is permanently + disabled when the feature is used. See + Documentation/livepatch/livepatch.txt for more information. + What: /sys/kernel/livepatch/<patch>/<object> Date: Nov 2014 KernelVersion: 3.19.0 diff --git a/Documentation/bpf/bpf_devel_QA.txt b/Documentation/bpf/bpf_devel_QA.txt new file mode 100644 index 000000000000..cefef855dea4 --- /dev/null +++ b/Documentation/bpf/bpf_devel_QA.txt @@ -0,0 +1,519 @@ +This document provides information for the BPF subsystem about various +workflows related to reporting bugs, submitting patches, and queueing +patches for stable kernels. + +For general information about submitting patches, please refer to +Documentation/process/. This document only describes additional specifics +related to BPF. + +Reporting bugs: +--------------- + +Q: How do I report bugs for BPF kernel code? + +A: Since all BPF kernel development as well as bpftool and iproute2 BPF + loader development happens through the netdev kernel mailing list, + please report any found issues around BPF to the following mailing + list: + + netdev@vger.kernel.org + + This may also include issues related to XDP, BPF tracing, etc. + + Given netdev has a high volume of traffic, please also add the BPF + maintainers to Cc (from kernel MAINTAINERS file): + + Alexei Starovoitov <ast@kernel.org> + Daniel Borkmann <daniel@iogearbox.net> + + In case a buggy commit has already been identified, make sure to keep + the actual commit authors in Cc as well for the report. They can + typically be identified through the kernel's git tree. + + Please do *not* report BPF issues to bugzilla.kernel.org since it + is a guarantee that the reported issue will be overlooked. + +Submitting patches: +------------------- + +Q: To which mailing list do I need to submit my BPF patches? + +A: Please submit your BPF patches to the netdev kernel mailing list: + + netdev@vger.kernel.org + + Historically, BPF came out of networking and has always been maintained + by the kernel networking community. Although these days BPF touches + many other subsystems as well, the patches are still routed mainly + through the networking community. + + In case your patch has changes in various different subsystems (e.g. + tracing, security, etc), make sure to Cc the related kernel mailing + lists and maintainers from there as well, so they are able to review + the changes and provide their Acked-by's to the patches. + +Q: Where can I find patches currently under discussion for BPF subsystem? + +A: All patches that are Cc'ed to netdev are queued for review under netdev + patchwork project: + + http://patchwork.ozlabs.org/project/netdev/list/ + + Those patches which target BPF, are assigned to a 'bpf' delegate for + further processing from BPF maintainers. The current queue with + patches under review can be found at: + + https://patchwork.ozlabs.org/project/netdev/list/?delegate=77147 + + Once the patches have been reviewed by the BPF community as a whole + and approved by the BPF maintainers, their status in patchwork will be + changed to 'Accepted' and the submitter will be notified by mail. This + means that the patches look good from a BPF perspective and have been + applied to one of the two BPF kernel trees. + + In case feedback from the community requires a respin of the patches, + their status in patchwork will be set to 'Changes Requested', and purged + from the current review queue. Likewise for cases where patches would + get rejected or are not applicable to the BPF trees (but assigned to + the 'bpf' delegate). + +Q: How do the changes make their way into Linux? + +A: There are two BPF kernel trees (git repositories). Once patches have + been accepted by the BPF maintainers, they will be applied to one + of the two BPF trees: + + https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/ + https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/ + + The bpf tree itself is for fixes only, whereas bpf-next for features, + cleanups or other kind of improvements ("next-like" content). This is + analogous to net and net-next trees for networking. Both bpf and + bpf-next will only have a master branch in order to simplify against + which branch patches should get rebased to. + + Accumulated BPF patches in the bpf tree will regularly get pulled + into the net kernel tree. Likewise, accumulated BPF patches accepted + into the bpf-next tree will make their way into net-next tree. net and + net-next are both run by David S. Miller. From there, they will go + into the kernel mainline tree run by Linus Torvalds. To read up on the + process of net and net-next being merged into the mainline tree, see + the netdev FAQ under: + + Documentation/networking/netdev-FAQ.txt + + Occasionally, to prevent merge conflicts, we might send pull requests + to other trees (e.g. tracing) with a small subset of the patches, but + net and net-next are always the main trees targeted for integration. + + The pull requests will contain a high-level summary of the accumulated + patches and can be searched on netdev kernel mailing list through the + following subject lines (yyyy-mm-dd is the date of the pull request): + + pull-request: bpf yyyy-mm-dd + pull-request: bpf-next yyyy-mm-dd + +Q: How do I indicate which tree (bpf vs. bpf-next) my patch should be + applied to? + +A: The process is the very same as described in the netdev FAQ, so + please read up on it. The subject line must indicate whether the + patch is a fix or rather "next-like" content in order to let the + maintainers know whether it is targeted at bpf or bpf-next. + + For fixes eventually landing in bpf -> net tree, the subject must + look like: + + git format-patch --subject-prefix='PATCH bpf' start..finish + + For features/improvements/etc that should eventually land in + bpf-next -> net-next, the subject must look like: + + git format-patch --subject-prefix='PATCH bpf-next' start..finish + + If unsure whether the patch or patch series should go into bpf + or net directly, or bpf-next or net-next directly, it is not a + problem either if the subject line says net or net-next as target. + It is eventually up to the maintainers to do the delegation of + the patches. + + If it is clear that patches should go into bpf or bpf-next tree, + please make sure to rebase the patches against those trees in + order to reduce potential conflicts. + + In case the patch or patch series has to be reworked and sent out + again in a second or later revision, it is also required to add a + version number (v2, v3, ...) into the subject prefix: + + git format-patch --subject-prefix='PATCH net-next v2' start..finish + + When changes have been requested to the patch series, always send the + whole patch series again with the feedback incorporated (never send + individual diffs on top of the old series). + +Q: What does it mean when a patch gets applied to bpf or bpf-next tree? + +A: It means that the patch looks good for mainline inclusion from + a BPF point of view. + + Be aware that this is not a final verdict that the patch will + automatically get accepted into net or net-next trees eventually: + + On the netdev kernel mailing list reviews can come in at any point + in time. If discussions around a patch conclude that they cannot + get included as-is, we will either apply a follow-up fix or drop + them from the trees entirely. Therefore, we also reserve to rebase + the trees when deemed necessary. After all, the purpose of the tree + is to i) accumulate and stage BPF patches for integration into trees + like net and net-next, and ii) run extensive BPF test suite and + workloads on the patches before they make their way any further. + + Once the BPF pull request was accepted by David S. Miller, then + the patches end up in net or net-next tree, respectively, and + make their way from there further into mainline. Again, see the + netdev FAQ for additional information e.g. on how often they are + merged to mainline. + +Q: How long do I need to wait for feedback on my BPF patches? + +A: We try to keep the latency low. The usual time to feedback will + be around 2 or 3 business days. It may vary depending on the + complexity of changes and current patch load. + +Q: How often do you send pull requests to major kernel trees like + net or net-next? + +A: Pull requests will be sent out rather often in order to not + accumulate too many patches in bpf or bpf-next. + + As a rule of thumb, expect pull requests for each tree regularly + at the end of the week. In some cases pull requests could additionally + come also in the middle of the week depending on the current patch + load or urgency. + +Q: Are patches applied to bpf-next when the merge window is open? + +A: For the time when the merge window is open, bpf-next will not be + processed. This is roughly analogous to net-next patch processing, + so feel free to read up on the netdev FAQ about further details. + + During those two weeks of merge window, we might ask you to resend + your patch series once bpf-next is open again. Once Linus released + a v*-rc1 after the merge window, we continue processing of bpf-next. + + For non-subscribers to kernel mailing lists, there is also a status + page run by David S. Miller on net-next that provides guidance: + + http://vger.kernel.org/~davem/net-next.html + +Q: I made a BPF verifier change, do I need to add test cases for + BPF kernel selftests? + +A: If the patch has changes to the behavior of the verifier, then yes, + it is absolutely necessary to add test cases to the BPF kernel + selftests suite. If they are not present and we think they are + needed, then we might ask for them before accepting any changes. + + In particular, test_verifier.c is tracking a high number of BPF test + cases, including a lot of corner cases that LLVM BPF back end may + generate out of the restricted C code. Thus, adding test cases is + absolutely crucial to make sure future changes do not accidentally + affect prior use-cases. Thus, treat those test cases as: verifier + behavior that is not tracked in test_verifier.c could potentially + be subject to change. + +Q: When should I add code to samples/bpf/ and when to BPF kernel + selftests? + +A: In general, we prefer additions to BPF kernel selftests rather than + samples/bpf/. The rationale is very simple: kernel selftests are + regularly run by various bots to test for kernel regressions. + + The more test cases we add to BPF selftests, the better the coverage + and the less likely it is that those could accidentally break. It is + not that BPF kernel selftests cannot demo how a specific feature can + be used. + + That said, samples/bpf/ may be a good place for people to get started, + so it might be advisable that simple demos of features could go into + samples/bpf/, but advanced functional and corner-case testing rather + into kernel selftests. + + If your sample looks like a test case, then go for BPF kernel selftests + instead! + +Q: When should I add code to the bpftool? + +A: The main purpose of bpftool (under tools/bpf/bpftool/) is to provide + a central user space tool for debugging and introspection of BPF programs + and maps that are active in the kernel. If UAPI changes related to BPF + enable for dumping additional information of programs or maps, then + bpftool should be extended as well to support dumping them. + +Q: When should I add code to iproute2's BPF loader? + +A: For UAPI changes related to the XDP or tc layer (e.g. cls_bpf), the + convention is that those control-path related changes are added to + iproute2's BPF loader as well from user space side. This is not only + useful to have UAPI changes properly designed to be usable, but also + to make those changes available to a wider user base of major + downstream distributions. + +Q: Do you accept patches as well for iproute2's BPF loader? + +A: Patches for the iproute2's BPF loader have to be sent to: + + netdev@vger.kernel.org + + While those patches are not processed by the BPF kernel maintainers, + please keep them in Cc as well, so they can be reviewed. + + The official git repository for iproute2 is run by Stephen Hemminger + and can be found at: + + https://git.kernel.org/pub/scm/linux/kernel/git/shemminger/iproute2.git/ + + The patches need to have a subject prefix of '[PATCH iproute2 master]' + or '[PATCH iproute2 net-next]'. 'master' or 'net-next' describes the + target branch where the patch should be applied to. Meaning, if kernel + changes went into the net-next kernel tree, then the related iproute2 + changes need to go into the iproute2 net-next branch, otherwise they + can be targeted at master branch. The iproute2 net-next branch will get + merged into the master branch after the current iproute2 version from + master has been released. + + Like BPF, the patches end up in patchwork under the netdev project and + are delegated to 'shemminger' for further processing: + + http://patchwork.ozlabs.org/project/netdev/list/?delegate=389 + +Q: What is the minimum requirement before I submit my BPF patches? + +A: When submitting patches, always take the time and properly test your + patches *prior* to submission. Never rush them! If maintainers find + that your patches have not been properly tested, it is a good way to + get them grumpy. Testing patch submissions is a hard requirement! + + Note, fixes that go to bpf tree *must* have a Fixes: tag included. The + same applies to fixes that target bpf-next, where the affected commit + is in net-next (or in some cases bpf-next). The Fixes: tag is crucial + in order to identify follow-up commits and tremendously helps for people + having to do backporting, so it is a must have! + + We also don't accept patches with an empty commit message. Take your + time and properly write up a high quality commit message, it is + essential! + + Think about it this way: other developers looking at your code a month + from now need to understand *why* a certain change has been done that + way, and whether there have been flaws in the analysis or assumptions + that the original author did. Thus providing a proper rationale and + describing the use-case for the changes is a must. + + Patch submissions with >1 patch must have a cover letter which includes + a high level description of the series. This high level summary will + then be placed into the merge commit by the BPF maintainers such that + it is also accessible from the git log for future reference. + +Q: What do I need to consider when adding a new instruction or feature + that would require BPF JIT and/or LLVM integration as well? + +A: We try hard to keep all BPF JITs up to date such that the same user + experience can be guaranteed when running BPF programs on different + architectures without having the program punt to the less efficient + interpreter in case the in-kernel BPF JIT is enabled. + + If you are unable to implement or test the required JIT changes for + certain architectures, please work together with the related BPF JIT + developers in order to get the feature implemented in a timely manner. + Please refer to the git log (arch/*/net/) to locate the necessary + people for helping out. + + Also always make sure to add BPF test cases (e.g. test_bpf.c and + test_verifier.c) for new instructions, so that they can receive + broad test coverage and help run-time testing the various BPF JITs. + + In case of new BPF instructions, once the changes have been accepted + into the Linux kernel, please implement support into LLVM's BPF back + end. See LLVM section below for further information. + +Stable submission: +------------------ + +Q: I need a specific BPF commit in stable kernels. What should I do? + +A: In case you need a specific fix in stable kernels, first check whether + the commit has already been applied in the related linux-*.y branches: + + https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/ + + If not the case, then drop an email to the BPF maintainers with the + netdev kernel mailing list in Cc and ask for the fix to be queued up: + + netdev@vger.kernel.org + + The process in general is the same as on netdev itself, see also the + netdev FAQ document. + +Q: Do you also backport to kernels not currently maintained as stable? + +A: No. If you need a specific BPF commit in kernels that are currently not + maintained by the stable maintainers, then you are on your own. + + The current stable and longterm stable kernels are all listed here: + + https://www.kernel.org/ + +Q: The BPF patch I am about to submit needs to go to stable as well. What + should I do? + +A: The same rules apply as with netdev patch submissions in general, see + netdev FAQ under: + + Documentation/networking/netdev-FAQ.txt + + Never add "Cc: stable@vger.kernel.org" to the patch description, but + ask the BPF maintainers to queue the patches instead. This can be done + with a note, for example, under the "---" part of the patch which does + not go into the git log. Alternatively, this can be done as a simple + request by mail instead. + +Q: Where do I find currently queued BPF patches that will be submitted + to stable? + +A: Once patches that fix critical bugs got applied into the bpf tree, they + are queued up for stable submission under: + + http://patchwork.ozlabs.org/bundle/bpf/stable/?state=* + + They will be on hold there at minimum until the related commit made its + way into the mainline kernel tree. + + After having been under broader exposure, the queued patches will be + submitted by the BPF maintainers to the stable maintainers. + +Testing patches: +---------------- + +Q: Which BPF kernel selftests version should I run my kernel against? + +A: If you run a kernel xyz, then always run the BPF kernel selftests from + that kernel xyz as well. Do not expect that the BPF selftest from the + latest mainline tree will pass all the time. + + In particular, test_bpf.c and test_verifier.c have a large number of + test cases and are constantly updated with new BPF test sequences, or + existing ones are adapted to verifier changes e.g. due to verifier + becoming smarter and being able to better track certain things. + +LLVM: +----- + +Q: Where do I find LLVM with BPF support? + +A: The BPF back end for LLVM is upstream in LLVM since version 3.7.1. + + All major distributions these days ship LLVM with BPF back end enabled, + so for the majority of use-cases it is not required to compile LLVM by + hand anymore, just install the distribution provided package. + + LLVM's static compiler lists the supported targets through 'llc --version', + make sure BPF targets are listed. Example: + + $ llc --version + LLVM (http://llvm.org/): + LLVM version 6.0.0svn + Optimized build. + Default target: x86_64-unknown-linux-gnu + Host CPU: skylake + + Registered Targets: + bpf - BPF (host endian) + bpfeb - BPF (big endian) + bpfel - BPF (little endian) + x86 - 32-bit X86: Pentium-Pro and above + x86-64 - 64-bit X86: EM64T and AMD64 + + For developers in order to utilize the latest features added to LLVM's + BPF back end, it is advisable to run the latest LLVM releases. Support + for new BPF kernel features such as additions to the BPF instruction + set are often developed together. + + All LLVM releases can be found at: http://releases.llvm.org/ + +Q: Got it, so how do I build LLVM manually anyway? + +A: You need cmake and gcc-c++ as build requisites for LLVM. Once you have + that set up, proceed with building the latest LLVM and clang version + from the git repositories: + + $ git clone http://llvm.org/git/llvm.git + $ cd llvm/tools + $ git clone --depth 1 http://llvm.org/git/clang.git + $ cd ..; mkdir build; cd build + $ cmake .. -DLLVM_TARGETS_TO_BUILD="BPF;X86" \ + -DBUILD_SHARED_LIBS=OFF \ + -DCMAKE_BUILD_TYPE=Release \ + -DLLVM_BUILD_RUNTIME=OFF + $ make -j $(getconf _NPROCESSORS_ONLN) + + The built binaries can then be found in the build/bin/ directory, where + you can point the PATH variable to. + +Q: Should I notify BPF kernel maintainers about issues in LLVM's BPF code + generation back end or about LLVM generated code that the verifier + refuses to accept? + +A: Yes, please do! LLVM's BPF back end is a key piece of the whole BPF + infrastructure and it ties deeply into verification of programs from the + kernel side. Therefore, any issues on either side need to be investigated + and fixed whenever necessary. + + Therefore, please make sure to bring them up at netdev kernel mailing + list and Cc BPF maintainers for LLVM and kernel bits: + + Yonghong Song <yhs@fb.com> + Alexei Starovoitov <ast@kernel.org> + Daniel Borkmann <daniel@iogearbox.net> + + LLVM also has an issue tracker where BPF related bugs can be found: + + https://bugs.llvm.org/buglist.cgi?quicksearch=bpf + + However, it is better to reach out through mailing lists with having + maintainers in Cc. + +Q: I have added a new BPF instruction to the kernel, how can I integrate + it into LLVM? + +A: LLVM has a -mcpu selector for the BPF back end in order to allow the + selection of BPF instruction set extensions. By default the 'generic' + processor target is used, which is the base instruction set (v1) of BPF. + + LLVM has an option to select -mcpu=probe where it will probe the host + kernel for supported BPF instruction set extensions and selects the + optimal set automatically. + + For cross-compilation, a specific version can be select manually as well. + + $ llc -march bpf -mcpu=help + Available CPUs for this target: + + generic - Select the generic processor. + probe - Select the probe processor. + v1 - Select the v1 processor. + v2 - Select the v2 processor. + [...] + + Newly added BPF instructions to the Linux kernel need to follow the same + scheme, bump the instruction set version and implement probing for the + extensions such that -mcpu=probe users can benefit from the optimization + transparently when upgrading their kernels. + + If you are unable to implement support for the newly added BPF instruction + please reach out to BPF developers for help. + + By the way, the BPF kernel selftests run with -mcpu=probe for better + test coverage. + +Happy BPF hacking! diff --git a/Documentation/devicetree/bindings/crypto/arm-cryptocell.txt b/Documentation/devicetree/bindings/crypto/arm-cryptocell.txt new file mode 100644 index 000000000000..cec8d5d74e26 --- /dev/null +++ b/Documentation/devicetree/bindings/crypto/arm-cryptocell.txt @@ -0,0 +1,22 @@ +Arm TrustZone CryptoCell cryptographic engine + +Required properties: +- compatible: Should be "arm,cryptocell-712-ree". +- reg: Base physical address of the engine and length of memory mapped region. +- interrupts: Interrupt number for the device. + +Optional properties: +- interrupt-parent: The phandle for the interrupt controller that services + interrupts for this device. +- clocks: Reference to the crypto engine clock. +- dma-coherent: Present if dma operations are coherent. + +Examples: + + arm_cc712: crypto@80000000 { + compatible = "arm,cryptocell-712-ree"; + interrupt-parent = <&intc>; + interrupts = < 0 30 4 >; + reg = < 0x80000000 0x10000 >; + + }; diff --git a/Documentation/devicetree/bindings/crypto/inside-secure-safexcel.txt b/Documentation/devicetree/bindings/crypto/inside-secure-safexcel.txt index fbc07d12322f..30c3ce6b502e 100644 --- a/Documentation/devicetree/bindings/crypto/inside-secure-safexcel.txt +++ b/Documentation/devicetree/bindings/crypto/inside-secure-safexcel.txt @@ -1,7 +1,8 @@ Inside Secure SafeXcel cryptographic engine Required properties: -- compatible: Should be "inside-secure,safexcel-eip197". +- compatible: Should be "inside-secure,safexcel-eip197" or + "inside-secure,safexcel-eip97". - reg: Base physical address of the engine and length of memory mapped region. - interrupts: Interrupt numbers for the rings and engine. - interrupt-names: Should be "ring0", "ring1", "ring2", "ring3", "eip", "mem". diff --git a/Documentation/devicetree/bindings/crypto/samsung,exynos-rng4.txt b/Documentation/devicetree/bindings/crypto/samsung,exynos-rng4.txt index 4ca8dd4d7e66..a13fbdb4bd88 100644 --- a/Documentation/devicetree/bindings/crypto/samsung,exynos-rng4.txt +++ b/Documentation/devicetree/bindings/crypto/samsung,exynos-rng4.txt @@ -2,7 +2,9 @@ Exynos Pseudo Random Number Generator Required properties: -- compatible : Should be "samsung,exynos4-rng". +- compatible : One of: + - "samsung,exynos4-rng" for Exynos4210 and Exynos4412 + - "samsung,exynos5250-prng" for Exynos5250+ - reg : Specifies base physical address and size of the registers map. - clocks : Phandle to clock-controller plus clock-specifier pair. - clock-names : "secss" as a clock name. diff --git a/Documentation/devicetree/bindings/crypto/st,stm32-cryp.txt b/Documentation/devicetree/bindings/crypto/st,stm32-cryp.txt new file mode 100644 index 000000000000..970487fa40b8 --- /dev/null +++ b/Documentation/devicetree/bindings/crypto/st,stm32-cryp.txt @@ -0,0 +1,19 @@ +* STMicroelectronics STM32 CRYP + +Required properties: +- compatible: Should be "st,stm32f756-cryp". +- reg: The address and length of the peripheral registers space +- clocks: The input clock of the CRYP instance +- interrupts: The CRYP interrupt + +Optional properties: +- resets: The input reset of the CRYP instance + +Example: +crypto@50060000 { + compatible = "st,stm32f756-cryp"; + reg = <0x50060000 0x400>; + interrupts = <79>; + clocks = <&rcc 0 STM32F7_AHB2_CLOCK(CRYP)>; + resets = <&rcc STM32F7_AHB2_RESET(CRYP)>; +}; diff --git a/Documentation/devicetree/bindings/gpio/gpio-axp209.txt b/Documentation/devicetree/bindings/gpio/gpio-axp209.txt index a6611304dd3c..fc42b2caa06d 100644 --- a/Documentation/devicetree/bindings/gpio/gpio-axp209.txt +++ b/Documentation/devicetree/bindings/gpio/gpio-axp209.txt @@ -1,10 +1,17 @@ -AXP209 GPIO controller +AXP209 GPIO & pinctrl controller This driver follows the usual GPIO bindings found in Documentation/devicetree/bindings/gpio/gpio.txt +This driver follows the usual pinctrl bindings found in +Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt + +This driver employs the per-pin muxing pattern. + Required properties: -- compatible: Should be "x-powers,axp209-gpio" +- compatible: Should be one of: + - "x-powers,axp209-gpio" + - "x-powers,axp813-gpio" - #gpio-cells: Should be two. The first cell is the pin number and the second is the GPIO flags. - gpio-controller: Marks the device node as a GPIO controller. @@ -28,3 +35,41 @@ axp209: pmic@34 { #gpio-cells = <2>; }; }; + +The GPIOs can be muxed to other functions and therefore, must be a subnode of +axp_gpio. + +Example: + +&axp_gpio { + gpio0_adc: gpio0-adc { + pins = "GPIO0"; + function = "adc"; + }; +}; + +&example_node { + pinctrl-names = "default"; + pinctrl-0 = <&gpio0_adc>; +}; + +GPIOs and their functions +------------------------- + +Each GPIO is independent from the other (i.e. GPIO0 in gpio_in function does +not force GPIO1 and GPIO2 to be in gpio_in function as well). + +axp209 +------ +GPIO | Functions +------------------------ +GPIO0 | gpio_in, gpio_out, ldo, adc +GPIO1 | gpio_in, gpio_out, ldo, adc +GPIO2 | gpio_in, gpio_out + +axp813 +------ +GPIO | Functions +------------------------ +GPIO0 | gpio_in, gpio_out, ldo, adc +GPIO1 | gpio_in, gpio_out, ldo diff --git a/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt b/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt index a7ac460ad657..9474138d776e 100644 --- a/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt +++ b/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt @@ -5,7 +5,7 @@ Required Properties: - compatible: should contain one or more of the following: - "renesas,gpio-r8a7743": for R8A7743 (RZ/G1M) compatible GPIO controller. - "renesas,gpio-r8a7745": for R8A7745 (RZ/G1E) compatible GPIO controller. - - "renesas,gpio-r8a7778": for R8A7778 (R-Mobile M1) compatible GPIO controller. + - "renesas,gpio-r8a7778": for R8A7778 (R-Car M1) compatible GPIO controller. - "renesas,gpio-r8a7779": for R8A7779 (R-Car H1) compatible GPIO controller. - "renesas,gpio-r8a7790": for R8A7790 (R-Car H2) compatible GPIO controller. - "renesas,gpio-r8a7791": for R8A7791 (R-Car M2-W) compatible GPIO controller. diff --git a/Documentation/devicetree/bindings/input/hid-over-i2c.txt b/Documentation/devicetree/bindings/input/hid-over-i2c.txt index 28e8bd8b7d64..4d3da9d91de4 100644 --- a/Documentation/devicetree/bindings/input/hid-over-i2c.txt +++ b/Documentation/devicetree/bindings/input/hid-over-i2c.txt @@ -31,7 +31,7 @@ device-specific compatible properties, which should be used in addition to the - vdd-supply: phandle of the regulator that provides the supply voltage. - post-power-on-delay-ms: time required by the device after enabling its regulators - before it is ready for communication. Must be used with 'vdd-supply'. + or powering it on, before it is ready for communication. Example: diff --git a/Documentation/devicetree/bindings/leds/leds-lm3692x.txt b/Documentation/devicetree/bindings/leds/leds-lm3692x.txt new file mode 100644 index 000000000000..6c9074f84a51 --- /dev/null +++ b/Documentation/devicetree/bindings/leds/leds-lm3692x.txt @@ -0,0 +1,49 @@ +* Texas Instruments - LM3692x Highly Efficient White LED Driver + +The LM3692x is an ultra-compact, highly efficient, +white-LED driver designed for LCD display backlighting. + +The main difference between the LM36922 and LM36923 is the number of +LED strings it supports. The LM36922 supports two strings while the LM36923 +supports three strings. + +Required properties: + - compatible: + "ti,lm36922" + "ti,lm36923" + - reg : I2C slave address + - #address-cells : 1 + - #size-cells : 0 + +Optional properties: + - enable-gpios : gpio pin to enable/disable the device. + - vled-supply : LED supply + +Required child properties: + - reg : 0 + +Optional child properties: + - label : see Documentation/devicetree/bindings/leds/common.txt + - linux,default-trigger : + see Documentation/devicetree/bindings/leds/common.txt + +Example: + +led-controller@36 { + compatible = "ti,lm3692x"; + reg = <0x36>; + #address-cells = <1>; + #size-cells = <0>; + + enable-gpios = <&gpio1 28 GPIO_ACTIVE_HIGH>; + vled-supply = <&vbatt>; + + led@0 { + reg = <0>; + label = "white:backlight_cluster"; + linux,default-trigger = "backlight"; + }; +} + +For more product information please see the link below: +http://www.ti.com/lit/ds/snvsa29/snvsa29.pdf diff --git a/Documentation/devicetree/bindings/leds/leds-lp8860.txt b/Documentation/devicetree/bindings/leds/leds-lp8860.txt index aad38dd94d4b..5f0e892ad759 100644 --- a/Documentation/devicetree/bindings/leds/leds-lp8860.txt +++ b/Documentation/devicetree/bindings/leds/leds-lp8860.txt @@ -6,23 +6,39 @@ current sinks that can be controlled by a PWM input signal, a SPI/I2C master, or both. Required properties: - - compatible: + - compatible : "ti,lp8860" - - reg - I2C slave address - - label - Used for naming LEDs + - reg : I2C slave address + - #address-cells : 1 + - #size-cells : 0 Optional properties: - - enable-gpio - gpio pin to enable/disable the device. - - supply - "vled" - LED supply + - enable-gpios : gpio pin to enable (active high)/disable the device. + - vled-supply : LED supply + +Required child properties: + - reg : 0 + +Optional child properties: + - label : see Documentation/devicetree/bindings/leds/common.txt + - linux,default-trigger : + see Documentation/devicetree/bindings/leds/common.txt Example: -leds: leds@6 { +led-controller@2d { compatible = "ti,lp8860"; + #address-cells = <1>; + #size-cells = <0>; reg = <0x2d>; - label = "display_cluster"; - enable-gpio = <&gpio1 28 GPIO_ACTIVE_HIGH>; + enable-gpios = <&gpio1 28 GPIO_ACTIVE_HIGH>; vled-supply = <&vbatt>; + + led@0 { + reg = <0>; + label = "white:backlight"; + linux,default-trigger = "backlight"; + }; } For more product information please see the link below: diff --git a/Documentation/devicetree/bindings/net/brcm,bcm7445-switch-v4.0.txt b/Documentation/devicetree/bindings/net/brcm,bcm7445-switch-v4.0.txt index 9a734d808aa7..b7336b9d6a3c 100644 --- a/Documentation/devicetree/bindings/net/brcm,bcm7445-switch-v4.0.txt +++ b/Documentation/devicetree/bindings/net/brcm,bcm7445-switch-v4.0.txt @@ -2,7 +2,10 @@ Required properties: -- compatible: should be "brcm,bcm7445-switch-v4.0" or "brcm,bcm7278-switch-v4.0" +- compatible: should be one of + "brcm,bcm7445-switch-v4.0" + "brcm,bcm7278-switch-v4.0" + "brcm,bcm7278-switch-v4.8" - reg: addresses and length of the register sets for the device, must be 6 pairs of register addresses and lengths - interrupts: interrupts for the devices, must be two interrupts diff --git a/Documentation/devicetree/bindings/net/can/can-transceiver.txt b/Documentation/devicetree/bindings/net/can/can-transceiver.txt new file mode 100644 index 000000000000..0011f53ff159 --- /dev/null +++ b/Documentation/devicetree/bindings/net/can/can-transceiver.txt @@ -0,0 +1,24 @@ +Generic CAN transceiver Device Tree binding +------------------------------ + +CAN transceiver typically limits the max speed in standard CAN and CAN FD +modes. Typically these limitations are static and the transceivers themselves +provide no way to detect this limitation at runtime. For this situation, +the "can-transceiver" node can be used. + +Required Properties: + max-bitrate: a positive non 0 value that determines the max + speed that CAN/CAN-FD can run. Any other value + will be ignored. + +Examples: + +Based on Texas Instrument's TCAN1042HGV CAN Transceiver + +m_can0 { + .... + can-transceiver { + max-bitrate = <5000000>; + }; + ... +}; diff --git a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt b/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt index 56d6cc336e1c..bfc0c433654f 100644 --- a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt +++ b/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt @@ -18,6 +18,12 @@ Optional properties: - xceiver-supply: Regulator that powers the CAN transceiver +- big-endian: This means the registers of FlexCAN controller are big endian. + This is optional property.i.e. if this property is not present in + device tree node then controller is assumed to be little endian. + if this property is present then controller is assumed to be big + endian. + Example: can@1c000 { diff --git a/Documentation/devicetree/bindings/net/can/m_can.txt b/Documentation/devicetree/bindings/net/can/m_can.txt index 63e90421d029..ed614383af9c 100644 --- a/Documentation/devicetree/bindings/net/can/m_can.txt +++ b/Documentation/devicetree/bindings/net/can/m_can.txt @@ -43,6 +43,11 @@ Required properties: Please refer to 2.4.1 Message RAM Configuration in Bosch M_CAN user manual for details. +Optional Subnode: +- can-transceiver : Can-transceiver subnode describing maximum speed + that can be used for CAN/CAN-FD modes. See + Documentation/devicetree/bindings/net/can/can-transceiver.txt + for details. Example: SoC dtsi: m_can1: can@20e8000 { @@ -63,4 +68,8 @@ Board dts: pinctrl-names = "default"; pinctrl-0 = <&pinctrl_m_can1>; status = "enabled"; + + can-transceiver { + max-bitrate = <5000000>; + }; }; diff --git a/Documentation/devicetree/bindings/net/can/rcar_can.txt b/Documentation/devicetree/bindings/net/can/rcar_can.txt index 06bb7cc334c8..94a7f33ac5e9 100644 --- a/Documentation/devicetree/bindings/net/can/rcar_can.txt +++ b/Documentation/devicetree/bindings/net/can/rcar_can.txt @@ -2,7 +2,9 @@ Renesas R-Car CAN controller Device Tree Bindings ------------------------------------------------- Required properties: -- compatible: "renesas,can-r8a7778" if CAN controller is a part of R8A7778 SoC. +- compatible: "renesas,can-r8a7743" if CAN controller is a part of R8A7743 SoC. + "renesas,can-r8a7745" if CAN controller is a part of R8A7745 SoC. + "renesas,can-r8a7778" if CAN controller is a part of R8A7778 SoC. "renesas,can-r8a7779" if CAN controller is a part of R8A7779 SoC. "renesas,can-r8a7790" if CAN controller is a part of R8A7790 SoC. "renesas,can-r8a7791" if CAN controller is a part of R8A7791 SoC. @@ -12,7 +14,8 @@ Required properties: "renesas,can-r8a7795" if CAN controller is a part of R8A7795 SoC. "renesas,can-r8a7796" if CAN controller is a part of R8A7796 SoC. "renesas,rcar-gen1-can" for a generic R-Car Gen1 compatible device. - "renesas,rcar-gen2-can" for a generic R-Car Gen2 compatible device. + "renesas,rcar-gen2-can" for a generic R-Car Gen2 or RZ/G1 + compatible device. "renesas,rcar-gen3-can" for a generic R-Car Gen3 compatible device. When compatible with the generic version, nodes must list the SoC-specific version corresponding to the platform first diff --git a/Documentation/devicetree/bindings/net/cortina,gemini-ethernet.txt b/Documentation/devicetree/bindings/net/cortina,gemini-ethernet.txt new file mode 100644 index 000000000000..6c559981d110 --- /dev/null +++ b/Documentation/devicetree/bindings/net/cortina,gemini-ethernet.txt @@ -0,0 +1,92 @@ +Cortina Systems Gemini Ethernet Controller +========================================== + +This ethernet controller is found in the Gemini SoC family: +StorLink SL3512 and SL3516, also known as Cortina Systems +CS3512 and CS3516. + +Required properties: +- compatible: must be "cortina,gemini-ethernet" +- reg: must contain the global registers and the V-bit and A-bit + memory areas, in total three register sets. +- syscon: a phandle to the system controller +- #address-cells: must be specified, must be <1> +- #size-cells: must be specified, must be <1> +- ranges: should be state like this giving a 1:1 address translation + for the subnodes + +The subnodes represents the two ethernet ports in this device. +They are not independent of each other since they share resources +in the parent node, and are thus children. + +Required subnodes: +- port0: contains the resources for ethernet port 0 +- port1: contains the resources for ethernet port 1 + +Required subnode properties: +- compatible: must be "cortina,gemini-ethernet-port" +- reg: must contain two register areas: the DMA/TOE memory and + the GMAC memory area of the port +- interrupts: should contain the interrupt line of the port. + this is nominally a level interrupt active high. +- resets: this must provide an SoC-integrated reset line for + the port. +- clocks: this should contain a handle to the PCLK clock for + clocking the silicon in this port +- clock-names: must be "PCLK" + +Optional subnode properties: +- phy-mode: see ethernet.txt +- phy-handle: see ethernet.txt + +Example: + +mdio-bus { + (...) + phy0: ethernet-phy@1 { + reg = <1>; + device_type = "ethernet-phy"; + }; + phy1: ethernet-phy@3 { + reg = <3>; + device_type = "ethernet-phy"; + }; +}; + + +ethernet@60000000 { + compatible = "cortina,gemini-ethernet"; + reg = <0x60000000 0x4000>, /* Global registers, queue */ + <0x60004000 0x2000>, /* V-bit */ + <0x60006000 0x2000>; /* A-bit */ + syscon = <&syscon>; + #address-cells = <1>; + #size-cells = <1>; + ranges; + + gmac0: ethernet-port@0 { + compatible = "cortina,gemini-ethernet-port"; + reg = <0x60008000 0x2000>, /* Port 0 DMA/TOE */ + <0x6000a000 0x2000>; /* Port 0 GMAC */ + interrupt-parent = <&intcon>; + interrupts = <1 IRQ_TYPE_LEVEL_HIGH>; + resets = <&syscon GEMINI_RESET_GMAC0>; + clocks = <&syscon GEMINI_CLK_GATE_GMAC0>; + clock-names = "PCLK"; + phy-mode = "rgmii"; + phy-handle = <&phy0>; + }; + + gmac1: ethernet-port@1 { + compatible = "cortina,gemini-ethernet-port"; + reg = <0x6000c000 0x2000>, /* Port 1 DMA/TOE */ + <0x6000e000 0x2000>; /* Port 1 GMAC */ + interrupt-parent = <&intcon>; + interrupts = <2 IRQ_TYPE_LEVEL_HIGH>; + resets = <&syscon GEMINI_RESET_GMAC1>; + clocks = <&syscon GEMINI_CLK_GATE_GMAC1>; + clock-names = "PCLK"; + phy-mode = "rgmii"; + phy-handle = <&phy1>; + }; +}; diff --git a/Documentation/devicetree/bindings/net/fsl-fec.txt b/Documentation/devicetree/bindings/net/fsl-fec.txt index f0dc94409107..2d41fb96ce0a 100644 --- a/Documentation/devicetree/bindings/net/fsl-fec.txt +++ b/Documentation/devicetree/bindings/net/fsl-fec.txt @@ -59,7 +59,7 @@ ethernet@83fec000 { reg = <0x83fec000 0x4000>; interrupts = <87>; phy-mode = "mii"; - phy-reset-gpios = <&gpio2 14 0>; /* GPIO2_14 */ + phy-reset-gpios = <&gpio2 14 GPIO_ACTIVE_LOW>; /* GPIO2_14 */ local-mac-address = [00 04 9F 01 1B B9]; phy-supply = <®_fec_supply>; }; @@ -71,7 +71,7 @@ ethernet@83fec000 { reg = <0x83fec000 0x4000>; interrupts = <87>; phy-mode = "mii"; - phy-reset-gpios = <&gpio2 14 0>; /* GPIO2_14 */ + phy-reset-gpios = <&gpio2 14 GPIO_ACTIVE_LOW>; /* GPIO2_14 */ local-mac-address = [00 04 9F 01 1B B9]; phy-supply = <®_fec_supply>; phy-handle = <ðphy>; diff --git a/Documentation/devicetree/bindings/net/ieee802154/adf7242.txt b/Documentation/devicetree/bindings/net/ieee802154/adf7242.txt index dea5124cdc52..d24172cc6d32 100644 --- a/Documentation/devicetree/bindings/net/ieee802154/adf7242.txt +++ b/Documentation/devicetree/bindings/net/ieee802154/adf7242.txt @@ -1,7 +1,7 @@ * ADF7242 IEEE 802.15.4 * Required properties: - - compatible: should be "adi,adf7242" + - compatible: should be "adi,adf7242", "adi,adf7241" - spi-max-frequency: maximal bus speed (12.5 MHz) - reg: the chipselect index - interrupts: the interrupt generated by the device via pin IRQ1. diff --git a/Documentation/devicetree/bindings/net/mediatek-net.txt b/Documentation/devicetree/bindings/net/mediatek-net.txt index 214eaa9a6683..53c13ee384a4 100644 --- a/Documentation/devicetree/bindings/net/mediatek-net.txt +++ b/Documentation/devicetree/bindings/net/mediatek-net.txt @@ -28,7 +28,7 @@ Required properties: - mediatek,sgmiisys: phandle to the syscon node that handles the SGMII setup which is required for those SoCs equipped with SGMII such as MT7622 SoC. - mediatek,pctl: phandle to the syscon node that handles the ports slew rate - and driver current + and driver current: only for MT2701 and MT7623 SoC Optional properties: - interrupt-parent: Should be the phandle for the interrupt controller diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt index 77d0b2a61ffa..d2169a56f5e3 100644 --- a/Documentation/devicetree/bindings/net/phy.txt +++ b/Documentation/devicetree/bindings/net/phy.txt @@ -53,6 +53,14 @@ Optional Properties: to ensure the integrated PHY is used. The absence of this property indicates the muxers should be configured so that the external PHY is used. +- reset-gpios: The GPIO phandle and specifier for the PHY reset signal. + +- reset-assert-us: Delay after the reset was asserted in microseconds. + If this property is missing the delay will be skipped. + +- reset-deassert-us: Delay after the reset was deasserted in microseconds. + If this property is missing the delay will be skipped. + Example: ethernet-phy@0 { @@ -60,4 +68,8 @@ ethernet-phy@0 { interrupt-parent = <&PIC>; interrupts = <35 IRQ_TYPE_EDGE_RISING>; reg = <0>; + + reset-gpios = <&gpio1 4 GPIO_ACTIVE_LOW>; + reset-assert-us = <1000>; + reset-deassert-us = <2000>; }; diff --git a/Documentation/devicetree/bindings/net/sff,sfp.txt b/Documentation/devicetree/bindings/net/sff,sfp.txt index 60e970ce10ee..f1c441bedf68 100644 --- a/Documentation/devicetree/bindings/net/sff,sfp.txt +++ b/Documentation/devicetree/bindings/net/sff,sfp.txt @@ -3,7 +3,9 @@ Transceiver Required properties: -- compatible : must be "sff,sfp" +- compatible : must be one of + "sff,sfp" for SFP modules + "sff,sff" for soldered down SFF modules Optional Properties: @@ -11,7 +13,8 @@ Optional Properties: interface - mod-def0-gpios : GPIO phandle and a specifier of the MOD-DEF0 (AKA Mod_ABS) - module presence input gpio signal, active (module absent) high + module presence input gpio signal, active (module absent) high. Must + not be present for SFF modules - los-gpios : GPIO phandle and a specifier of the Receiver Loss of Signal Indication input gpio signal, active (signal lost) high @@ -24,10 +27,11 @@ Optional Properties: - rate-select0-gpios : GPIO phandle and a specifier of the Rx Signaling Rate Select (AKA RS0) output gpio signal, low: low Rx rate, high: high Rx rate + Must not be present for SFF modules - rate-select1-gpios : GPIO phandle and a specifier of the Tx Signaling Rate Select (AKA RS1) output gpio signal (SFP+ only), low: low Tx rate, high: - high Tx rate + high Tx rate. Must not be present for SFF modules Example #1: Direct serdes to SFP connection diff --git a/Documentation/devicetree/bindings/net/socionext,uniphier-ave4.txt b/Documentation/devicetree/bindings/net/socionext,uniphier-ave4.txt new file mode 100644 index 000000000000..270ea4efff13 --- /dev/null +++ b/Documentation/devicetree/bindings/net/socionext,uniphier-ave4.txt @@ -0,0 +1,48 @@ +* Socionext AVE ethernet controller + +This describes the devicetree bindings for AVE ethernet controller +implemented on Socionext UniPhier SoCs. + +Required properties: + - compatible: Should be + - "socionext,uniphier-pro4-ave4" : for Pro4 SoC + - "socionext,uniphier-pxs2-ave4" : for PXs2 SoC + - "socionext,uniphier-ld11-ave4" : for LD11 SoC + - "socionext,uniphier-ld20-ave4" : for LD20 SoC + - reg: Address where registers are mapped and size of region. + - interrupts: Should contain the MAC interrupt. + - phy-mode: See ethernet.txt in the same directory. Allow to choose + "rgmii", "rmii", or "mii" according to the PHY. + - phy-handle: Should point to the external phy device. + See ethernet.txt file in the same directory. + - clocks: A phandle to the clock for the MAC. + +Optional properties: + - resets: A phandle to the reset control for the MAC. + - local-mac-address: See ethernet.txt in the same directory. + +Required subnode: + - mdio: A container for child nodes representing phy nodes. + See phy.txt in the same directory. + +Example: + + ether: ethernet@65000000 { + compatible = "socionext,uniphier-ld20-ave4"; + reg = <0x65000000 0x8500>; + interrupts = <0 66 4>; + phy-mode = "rgmii"; + phy-handle = <ðphy>; + clocks = <&sys_clk 6>; + resets = <&sys_rst 6>; + local-mac-address = [00 00 00 00 00 00]; + + mdio { + #address-cells = <1>; + #size-cells = <0>; + + ethphy: ethphy@1 { + reg = <1>; + }; + }; + }; diff --git a/Documentation/devicetree/bindings/net/socionext-netsec.txt b/Documentation/devicetree/bindings/net/socionext-netsec.txt new file mode 100644 index 000000000000..0cff94fb0433 --- /dev/null +++ b/Documentation/devicetree/bindings/net/socionext-netsec.txt @@ -0,0 +1,53 @@ +* Socionext NetSec Ethernet Controller IP + +Required properties: +- compatible: Should be "socionext,synquacer-netsec" +- reg: Address and length of the control register area, followed by the + address and length of the EEPROM holding the MAC address and + microengine firmware +- interrupts: Should contain ethernet controller interrupt +- clocks: phandle to the PHY reference clock +- clock-names: Should be "phy_ref_clk" +- phy-mode: See ethernet.txt file in the same directory +- phy-handle: See ethernet.txt in the same directory. + +- mdio device tree subnode: When the Netsec has a phy connected to its local + mdio, there must be device tree subnode with the following + required properties: + + - #address-cells: Must be <1>. + - #size-cells: Must be <0>. + + For each phy on the mdio bus, there must be a node with the following + fields: + - compatible: Refer to phy.txt + - reg: phy id used to communicate to phy. + +Optional properties: (See ethernet.txt file in the same directory) +- dma-coherent: Boolean property, must only be present if memory + accesses performed by the device are cache coherent. +- local-mac-address: See ethernet.txt in the same directory. +- mac-address: See ethernet.txt in the same directory. +- max-speed: See ethernet.txt in the same directory. +- max-frame-size: See ethernet.txt in the same directory. + +Example: + eth0: ethernet@522d0000 { + compatible = "socionext,synquacer-netsec"; + reg = <0 0x522d0000 0x0 0x10000>, <0 0x10000000 0x0 0x10000>; + interrupts = <GIC_SPI 176 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&clk_netsec>; + clock-names = "phy_ref_clk"; + phy-mode = "rgmii"; + max-speed = <1000>; + max-frame-size = <9000>; + phy-handle = <&phy1>; + + mdio { + #address-cells = <1>; + #size-cells = <0>; + phy1: ethernet-phy@1 { + compatible = "ethernet-phy-ieee802.3-c22"; + reg = <1>; + }; + }; diff --git a/Documentation/devicetree/bindings/net/ti,wilink-st.txt b/Documentation/devicetree/bindings/net/ti-bluetooth.txt index 1649c1f66b07..6d03ff8c7068 100644 --- a/Documentation/devicetree/bindings/net/ti,wilink-st.txt +++ b/Documentation/devicetree/bindings/net/ti-bluetooth.txt @@ -1,10 +1,18 @@ -TI WiLink 7/8 (wl12xx/wl18xx) Shared Transport BT/FM/GPS devices +Texas Instruments Bluetooth Chips +--------------------------------- + +This documents the binding structure and common properties for serial +attached TI Bluetooth devices. The following chips are included in this +binding: + +* TI CC256x Bluetooth devices +* TI WiLink 7/8 (wl12xx/wl18xx) Shared Transport BT/FM/GPS devices TI WiLink devices have a UART interface for providing Bluetooth, FM radio, and GPS over what's called "shared transport". The shared transport is standard BT HCI protocol with additional channels for the other functions. -These devices also have a separate WiFi interface as described in +TI WiLink devices also have a separate WiFi interface as described in wireless/ti,wlcore.txt. This bindings follows the UART slave device binding in @@ -12,6 +20,7 @@ This bindings follows the UART slave device binding in Required properties: - compatible: should be one of the following: + "ti,cc2560" "ti,wl1271-st" "ti,wl1273-st" "ti,wl1281-st" @@ -32,6 +41,9 @@ Optional properties: See ../clocks/clock-bindings.txt for details. - clock-names : Must include the following entry: "ext_clock" (External clock provided to the TI combo chip). + - nvmem-cells: phandle to nvmem data cell that contains a 6 byte BD address + with the most significant byte first (big-endian). + - nvmem-cell-names: "bd-address" (required when nvmem-cells is specified) Example: @@ -43,5 +55,7 @@ Example: enable-gpios = <&gpio1 7 GPIO_ACTIVE_HIGH>; clocks = <&clk32k_wl18xx>; clock-names = "ext_clock"; + nvmem-cells = <&bd_address>; + nvmem-cell-names = "bd-address"; }; }; diff --git a/Documentation/devicetree/bindings/net/wireless/mediatek,mt76.txt b/Documentation/devicetree/bindings/net/wireless/mediatek,mt76.txt new file mode 100644 index 000000000000..0c17a0ec9b7b --- /dev/null +++ b/Documentation/devicetree/bindings/net/wireless/mediatek,mt76.txt @@ -0,0 +1,32 @@ +* MediaTek mt76xx devices + +This node provides properties for configuring the MediaTek mt76xx wireless +device. The node is expected to be specified as a child node of the PCI +controller to which the wireless chip is connected. + +Optional properties: + +- mac-address: See ethernet.txt in the parent directory +- local-mac-address: See ethernet.txt in the parent directory +- ieee80211-freq-limit: See ieee80211.txt +- mediatek,mtd-eeprom: Specify a MTD partition + offset containing EEPROM data + +Optional nodes: +- led: Properties for a connected LED + Optional properties: + - led-sources: See Documentation/devicetree/bindings/leds/common.txt + +&pcie { + pcie0 { + wifi@0,0 { + compatible = "mediatek,mt76"; + reg = <0x0000 0 0 0 0>; + ieee80211-freq-limit = <5000000 6000000>; + mediatek,mtd-eeprom = <&factory 0x8000>; + + led { + led-sources = <2>; + }; + }; + }; +}; diff --git a/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt b/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt index 74d7f0af209c..3d2a031217da 100644 --- a/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt +++ b/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt @@ -41,6 +41,9 @@ Optional properties: - qcom,msi_addr: MSI interrupt address. - qcom,msi_base: Base value to add before writing MSI data into MSI address register. +- qcom,ath10k-calibration-variant: string to search for in the board-2.bin + variant list with the same bus and device + specific ids - qcom,ath10k-calibration-data : calibration data + board specific data as an array, the length can vary between hw versions. diff --git a/Documentation/devicetree/bindings/power/reset/imx-snvs-poweroff.txt b/Documentation/devicetree/bindings/power/reset/imx-snvs-poweroff.txt deleted file mode 100644 index 1b81fcd9fb72..000000000000 --- a/Documentation/devicetree/bindings/power/reset/imx-snvs-poweroff.txt +++ /dev/null @@ -1,23 +0,0 @@ -i.mx6 Poweroff Driver - -SNVS_LPCR in SNVS module can power off the whole system by pull -PMIC_ON_REQ low if PMIC_ON_REQ is connected with external PMIC. -If you don't want to use PMIC_ON_REQ as power on/off control, -please set status='disabled' to disable this driver. - -Required Properties: --compatible: "fsl,sec-v4.0-poweroff" --reg: Specifies the physical address of the SNVS_LPCR register - -Example: - snvs@20cc000 { - compatible = "fsl,sec-v4.0-mon", "simple-bus"; - #address-cells = <1>; - #size-cells = <1>; - ranges = <0 0x020cc000 0x4000>; - ..... - snvs_poweroff: snvs-poweroff@38 { - compatible = "fsl,sec-v4.0-poweroff"; - reg = <0x38 0x4>; - }; - } diff --git a/Documentation/devicetree/bindings/power/supply/bq27xxx.txt b/Documentation/devicetree/bindings/power/supply/bq27xxx.txt index 6858e1a804ad..615c1cb6889f 100644 --- a/Documentation/devicetree/bindings/power/supply/bq27xxx.txt +++ b/Documentation/devicetree/bindings/power/supply/bq27xxx.txt @@ -15,6 +15,7 @@ Required properties: * "ti,bq27520g2" - BQ27520-g2 * "ti,bq27520g3" - BQ27520-g3 * "ti,bq27520g4" - BQ27520-g4 + * "ti,bq27521" - BQ27521 * "ti,bq27530" - BQ27530 * "ti,bq27531" - BQ27531 * "ti,bq27541" - BQ27541 diff --git a/Documentation/devicetree/bindings/powerpc/fsl/mpc5200.txt b/Documentation/devicetree/bindings/powerpc/fsl/mpc5200.txt index 4ccb2cd5df94..d096cf461d81 100644 --- a/Documentation/devicetree/bindings/powerpc/fsl/mpc5200.txt +++ b/Documentation/devicetree/bindings/powerpc/fsl/mpc5200.txt @@ -195,4 +195,4 @@ External interrupts: fsl,mpc5200-mscan nodes ----------------------- -See file can.txt in this directory. +See file Documentation/devicetree/bindings/powerpc/fsl/mpc5200.txt diff --git a/Documentation/devicetree/bindings/rng/brcm,bcm2835.txt b/Documentation/devicetree/bindings/rng/brcm,bcm2835.txt index 26542690b578..627b29531a32 100644 --- a/Documentation/devicetree/bindings/rng/brcm,bcm2835.txt +++ b/Documentation/devicetree/bindings/rng/brcm,bcm2835.txt @@ -1,11 +1,19 @@ -BCM2835 Random number generator +BCM2835/6368 Random number generator Required properties: -- compatible : should be "brcm,bcm2835-rng" or "brcm,bcm-nsp-rng" or - "brcm,bcm5301x-rng" +- compatible : should be one of + "brcm,bcm2835-rng" + "brcm,bcm-nsp-rng" + "brcm,bcm5301x-rng" or + "brcm,bcm6368-rng" - reg : Specifies base physical address and size of the registers. +Optional properties: + +- clocks : phandle to clock-controller plus clock-specifier pair +- clock-names : "ipsec" as a clock name + Example: rng { @@ -17,3 +25,11 @@ rng@18033000 { compatible = "brcm,bcm-nsp-rng"; reg = <0x18033000 0x14>; }; + +random: rng@10004180 { + compatible = "brcm,bcm6368-rng"; + reg = <0x10004180 0x14>; + + clocks = <&periph_clk 18>; + clock-names = "ipsec"; +}; diff --git a/Documentation/devicetree/bindings/rng/brcm,bcm6368.txt b/Documentation/devicetree/bindings/rng/brcm,bcm6368.txt deleted file mode 100644 index 4b5ac600bfbd..000000000000 --- a/Documentation/devicetree/bindings/rng/brcm,bcm6368.txt +++ /dev/null @@ -1,17 +0,0 @@ -BCM6368 Random number generator - -Required properties: - -- compatible : should be "brcm,bcm6368-rng" -- reg : Specifies base physical address and size of the registers -- clocks : phandle to clock-controller plus clock-specifier pair -- clock-names : "ipsec" as a clock name - -Example: - random: rng@10004180 { - compatible = "brcm,bcm6368-rng"; - reg = <0x10004180 0x14>; - - clocks = <&periph_clk 18>; - clock-names = "ipsec"; - }; diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt index 918972babcd8..f4a32463ca48 100644 --- a/Documentation/fault-injection/fault-injection.txt +++ b/Documentation/fault-injection/fault-injection.txt @@ -30,6 +30,12 @@ o fail_mmc_request injects MMC data errors on devices permitted by setting debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request +o fail_function + + injects error return on specific functions, which are marked by + ALLOW_ERROR_INJECTION() macro, by setting debugfs entries + under /sys/kernel/debug/fail_function. No boot option supported. + Configure fault-injection capabilities behavior ----------------------------------------------- @@ -123,6 +129,29 @@ configuration of fault-injection capabilities. default is 'N', setting it to 'Y' will disable failure injections when dealing with private (address space) futexes. +- /sys/kernel/debug/fail_function/inject: + + Format: { 'function-name' | '!function-name' | '' } + specifies the target function of error injection by name. + If the function name leads '!' prefix, given function is + removed from injection list. If nothing specified ('') + injection list is cleared. + +- /sys/kernel/debug/fail_function/injectable: + + (read only) shows error injectable functions and what type of + error values can be specified. The error type will be one of + below; + - NULL: retval must be 0. + - ERRNO: retval must be -1 to -MAX_ERRNO (-4096). + - ERR_NULL: retval must be 0 or -1 to -MAX_ERRNO (-4096). + +- /sys/kernel/debug/fail_function/<functiuon-name>/retval: + + specifies the "error" return value to inject to the given + function for given function. This will be created when + user specifies new injection entry. + o Boot option In order to inject faults while debugfs is not available (early boot time), @@ -268,6 +297,45 @@ trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT echo "Injecting errors into the module $module... (interrupt to stop)" sleep 1000000 +------------------------------------------------------------------------------ + +o Inject open_ctree error while btrfs mount + +#!/bin/bash + +rm -f testfile.img +dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1 +DEVICE=$(losetup --show -f testfile.img) +mkfs.btrfs -f $DEVICE +mkdir -p tmpmnt + +FAILTYPE=fail_function +FAILFUNC=open_ctree +echo $FAILFUNC > /sys/kernel/debug/$FAILTYPE/inject +echo -12 > /sys/kernel/debug/$FAILTYPE/$FAILFUNC/retval +echo N > /sys/kernel/debug/$FAILTYPE/task-filter +echo 100 > /sys/kernel/debug/$FAILTYPE/probability +echo 0 > /sys/kernel/debug/$FAILTYPE/interval +echo -1 > /sys/kernel/debug/$FAILTYPE/times +echo 0 > /sys/kernel/debug/$FAILTYPE/space +echo 1 > /sys/kernel/debug/$FAILTYPE/verbose + +mount -t btrfs $DEVICE tmpmnt +if [ $? -ne 0 ] +then + echo "SUCCESS!" +else + echo "FAILED!" + umount tmpmnt +fi + +echo > /sys/kernel/debug/$FAILTYPE/inject + +rmdir tmpmnt +losetup -d $DEVICE +rm testfile.img + + Tool to run command with failslab or fail_page_alloc ---------------------------------------------------- In order to make it easier to accomplish the tasks mentioned above, we can use diff --git a/Documentation/gpio/board.txt b/Documentation/gpio/board.txt index a0f61898d493..659bb19f5b3c 100644 --- a/Documentation/gpio/board.txt +++ b/Documentation/gpio/board.txt @@ -2,6 +2,7 @@ GPIO Mappings ============= This document explains how GPIOs can be assigned to given devices and functions. + Note that it only applies to the new descriptor-based interface. For a description of the deprecated integer-based GPIO interface please refer to gpio-legacy.txt (actually, there is no real mapping possible with the old @@ -49,7 +50,7 @@ This property will make GPIOs 15, 16 and 17 available to the driver under the power = gpiod_get(dev, "power", GPIOD_OUT_HIGH); -The led GPIOs will be active-high, while the power GPIO will be active-low (i.e. +The led GPIOs will be active high, while the power GPIO will be active low (i.e. gpiod_is_active_low(power) will be true). The second parameter of the gpiod_get() functions, the con_id string, has to be @@ -122,9 +123,14 @@ where can be NULL, in which case it will match any function. - idx is the index of the GPIO within the function. - flags is defined to specify the following properties: - * GPIOF_ACTIVE_LOW - to configure the GPIO as active-low - * GPIOF_OPEN_DRAIN - GPIO pin is open drain type. - * GPIOF_OPEN_SOURCE - GPIO pin is open source type. + * GPIO_ACTIVE_HIGH - GPIO line is active high + * GPIO_ACTIVE_LOW - GPIO line is active low + * GPIO_OPEN_DRAIN - GPIO line is set up as open drain + * GPIO_OPEN_SOURCE - GPIO line is set up as open source + * GPIO_PERSISTENT - GPIO line is persistent during + suspend/resume and maintains its value + * GPIO_TRANSITORY - GPIO line is transitory and may loose its + electrical state during suspend/resume In the future, these flags might be extended to support more properties. diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt index 63e1bd1d88e3..d53e5b5cfc9c 100644 --- a/Documentation/gpio/consumer.txt +++ b/Documentation/gpio/consumer.txt @@ -66,6 +66,15 @@ for the GPIO. Values can be: * GPIOD_IN to initialize the GPIO as input. * GPIOD_OUT_LOW to initialize the GPIO as output with a value of 0. * GPIOD_OUT_HIGH to initialize the GPIO as output with a value of 1. +* GPIOD_OUT_LOW_OPEN_DRAIN same as GPIOD_OUT_LOW but also enforce the line + to be electrically used with open drain. +* GPIOD_OUT_HIGH_OPEN_DRAIN same as GPIOD_OUT_HIGH but also enforce the line + to be electrically used with open drain. + +The two last flags are used for use cases where open drain is mandatory, such +as I2C: if the line is not already configured as open drain in the mappings +(see board.txt), then open drain will be enforced anyway and a warning will be +printed that the board configuration needs to be updated to match the use case. Both functions return either a valid GPIO descriptor, or an error code checkable with IS_ERR() (they will never return a NULL pointer). -ENOENT will be returned @@ -184,7 +193,7 @@ A driver can also query the current direction of a GPIO: int gpiod_get_direction(const struct gpio_desc *desc) -This function will return either GPIOF_DIR_IN or GPIOF_DIR_OUT. +This function returns 0 for output, 1 for input, or an error code in case of error. Be aware that there is no default direction for GPIOs. Therefore, **using a GPIO without setting its direction first is illegal and will result in undefined @@ -240,59 +249,71 @@ that can't be accessed from hardIRQ handlers, these calls act the same as the spinlock-safe calls. -Active-low State and Raw GPIO Values ------------------------------------- -Device drivers like to manage the logical state of a GPIO, i.e. the value their -device will actually receive, no matter what lies between it and the GPIO line. -In some cases, it might make sense to control the actual GPIO line value. The -following set of calls ignore the active-low property of a GPIO and work on the -raw line value: - - int gpiod_get_raw_value(const struct gpio_desc *desc) - void gpiod_set_raw_value(struct gpio_desc *desc, int value) - int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc) - void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value) - int gpiod_direction_output_raw(struct gpio_desc *desc, int value) - -The active-low state of a GPIO can also be queried using the following call: - - int gpiod_is_active_low(const struct gpio_desc *desc) - -Note that these functions should only be used with great moderation ; a driver -should not have to care about the physical line level. - - -The active-low property ------------------------ - -As a driver should not have to care about the physical line level, all of the +The active low and open drain semantics +--------------------------------------- +As a consumer should not have to care about the physical line level, all of the gpiod_set_value_xxx() or gpiod_set_array_value_xxx() functions operate with -the *logical* value. With this they take the active-low property into account. -This means that they check whether the GPIO is configured to be active-low, +the *logical* value. With this they take the active low property into account. +This means that they check whether the GPIO is configured to be active low, and if so, they manipulate the passed value before the physical line level is driven. +The same is applicable for open drain or open source output lines: those do not +actively drive their output high (open drain) or low (open source), they just +switch their output to a high impedance value. The consumer should not need to +care. (For details read about open drain in driver.txt.) + With this, all the gpiod_set_(array)_value_xxx() functions interpret the -parameter "value" as "active" ("1") or "inactive" ("0"). The physical line +parameter "value" as "asserted" ("1") or "de-asserted" ("0"). The physical line level will be driven accordingly. -As an example, if the active-low property for a dedicated GPIO is set, and the -gpiod_set_(array)_value_xxx() passes "active" ("1"), the physical line level +As an example, if the active low property for a dedicated GPIO is set, and the +gpiod_set_(array)_value_xxx() passes "asserted" ("1"), the physical line level will be driven low. To summarize: -Function (example) active-low property physical line -gpiod_set_raw_value(desc, 0); don't care low -gpiod_set_raw_value(desc, 1); don't care high -gpiod_set_value(desc, 0); default (active-high) low -gpiod_set_value(desc, 1); default (active-high) high -gpiod_set_value(desc, 0); active-low high -gpiod_set_value(desc, 1); active-low low - -Please note again that the set_raw/get_raw functions should be avoided as much -as possible, especially by drivers which should not care about the actual -physical line level and worry about the logical value instead. +Function (example) line property physical line +gpiod_set_raw_value(desc, 0); don't care low +gpiod_set_raw_value(desc, 1); don't care high +gpiod_set_value(desc, 0); default (active high) low +gpiod_set_value(desc, 1); default (active high) high +gpiod_set_value(desc, 0); active low high +gpiod_set_value(desc, 1); active low low +gpiod_set_value(desc, 0); default (active high) low +gpiod_set_value(desc, 1); default (active high) high +gpiod_set_value(desc, 0); open drain low +gpiod_set_value(desc, 1); open drain high impedance +gpiod_set_value(desc, 0); open source high impedance +gpiod_set_value(desc, 1); open source high + +It is possible to override these semantics using the *set_raw/'get_raw functions +but it should be avoided as much as possible, especially by system-agnostic drivers +which should not need to care about the actual physical line level and worry about +the logical value instead. + + +Accessing raw GPIO values +------------------------- +Consumers exist that need to manage the logical state of a GPIO line, i.e. the value +their device will actually receive, no matter what lies between it and the GPIO +line. + +The following set of calls ignore the active-low or open drain property of a GPIO and +work on the raw line value: + + int gpiod_get_raw_value(const struct gpio_desc *desc) + void gpiod_set_raw_value(struct gpio_desc *desc, int value) + int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc) + void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value) + int gpiod_direction_output_raw(struct gpio_desc *desc, int value) + +The active low state of a GPIO can also be queried using the following call: + + int gpiod_is_active_low(const struct gpio_desc *desc) + +Note that these functions should only be used with great moderation; a driver +should not have to care about the physical line level or open drain semantics. Access multiple GPIOs with a single function call diff --git a/Documentation/gpio/driver.txt b/Documentation/gpio/driver.txt index d8de1c7de85a..3392a0fd4c23 100644 --- a/Documentation/gpio/driver.txt +++ b/Documentation/gpio/driver.txt @@ -88,6 +88,10 @@ ending up in the pin control back-end "behind" the GPIO controller, usually closer to the actual pins. This way the pin controller can manage the below listed GPIO configurations. +If a pin controller back-end is used, the GPIO controller or hardware +description needs to provide "GPIO ranges" mapping the GPIO line offsets to pin +numbers on the pin controller so they can properly cross-reference each other. + GPIOs with debounce support --------------------------- diff --git a/Documentation/gpio/sysfs.txt b/Documentation/gpio/sysfs.txt index aeab01aa4d00..6cdeab8650cd 100644 --- a/Documentation/gpio/sysfs.txt +++ b/Documentation/gpio/sysfs.txt @@ -1,6 +1,17 @@ GPIO Sysfs Interface for Userspace ================================== +THIS ABI IS DEPRECATED, THE ABI DOCUMENTATION HAS BEEN MOVED TO +Documentation/ABI/obsolete/sysfs-gpio AND NEW USERSPACE CONSUMERS +ARE SUPPOSED TO USE THE CHARACTER DEVICE ABI. THIS OLD SYSFS ABI WILL +NOT BE DEVELOPED (NO NEW FEATURES), IT WILL JUST BE MAINTAINED. + +Refer to the examples in tools/gpio/* for an introduction to the new +character device ABI. Also see the userspace header in +include/uapi/linux/gpio.h + +The deprecated sysfs ABI +------------------------ Platforms which use the "gpiolib" implementors framework may choose to configure a sysfs user interface to GPIOs. This is different from the debugfs interface, since it provides control over GPIO direction and diff --git a/Documentation/input/multi-touch-protocol.rst b/Documentation/input/multi-touch-protocol.rst index 8035868c56bc..b51751a0cd5d 100644 --- a/Documentation/input/multi-touch-protocol.rst +++ b/Documentation/input/multi-touch-protocol.rst @@ -269,10 +269,11 @@ ABS_MT_ORIENTATION The orientation of the touching ellipse. The value should describe a signed quarter of a revolution clockwise around the touch center. The signed value range is arbitrary, but zero should be returned for an ellipse aligned with - the Y axis of the surface, a negative value when the ellipse is turned to - the left, and a positive value when the ellipse is turned to the - right. When completely aligned with the X axis, the range max should be - returned. + the Y axis (north) of the surface, a negative value when the ellipse is + turned to the left, and a positive value when the ellipse is turned to the + right. When aligned with the X axis in the positive direction, the range + max should be returned; when aligned with the X axis in the negative + direction, the range -max should be returned. Touch ellipsis are symmetrical by default. For devices capable of true 360 degree orientation, the reported orientation must exceed the range max to diff --git a/Documentation/livepatch/livepatch.txt b/Documentation/livepatch/livepatch.txt index ecdb18104ab0..1ae2de758c08 100644 --- a/Documentation/livepatch/livepatch.txt +++ b/Documentation/livepatch/livepatch.txt @@ -72,8 +72,7 @@ example, they add a NULL pointer or a boundary check, fix a race by adding a missing memory barrier, or add some locking around a critical section. Most of these changes are self contained and the function presents itself the same way to the rest of the system. In this case, the functions might -be updated independently one by one. (This can be done by setting the -'immediate' flag in the klp_patch struct.) +be updated independently one by one. But there are more complex fixes. For example, a patch might change ordering of locking in multiple functions at the same time. Or a patch @@ -125,12 +124,6 @@ safe to patch tasks: b) Patching CPU-bound user tasks. If the task is highly CPU-bound then it will get patched the next time it gets interrupted by an IRQ. - c) In the future it could be useful for applying patches for - architectures which don't yet have HAVE_RELIABLE_STACKTRACE. In - this case you would have to signal most of the tasks on the - system. However this isn't supported yet because there's - currently no way to patch kthreads without - HAVE_RELIABLE_STACKTRACE. 3. For idle "swapper" tasks, since they don't ever exit the kernel, they instead have a klp_update_patch_state() call in the idle loop which @@ -138,27 +131,16 @@ safe to patch tasks: (Note there's not yet such an approach for kthreads.) -All the above approaches may be skipped by setting the 'immediate' flag -in the 'klp_patch' struct, which will disable per-task consistency and -patch all tasks immediately. This can be useful if the patch doesn't -change any function or data semantics. Note that, even with this flag -set, it's possible that some tasks may still be running with an old -version of the function, until that function returns. +Architectures which don't have HAVE_RELIABLE_STACKTRACE solely rely on +the second approach. It's highly likely that some tasks may still be +running with an old version of the function, until that function +returns. In this case you would have to signal the tasks. This +especially applies to kthreads. They may not be woken up and would need +to be forced. See below for more information. -There's also an 'immediate' flag in the 'klp_func' struct which allows -you to specify that certain functions in the patch can be applied -without per-task consistency. This might be useful if you want to patch -a common function like schedule(), and the function change doesn't need -consistency but the rest of the patch does. - -For architectures which don't have HAVE_RELIABLE_STACKTRACE, the user -must set patch->immediate which causes all tasks to be patched -immediately. This option should be used with care, only when the patch -doesn't change any function or data semantics. - -In the future, architectures which don't have HAVE_RELIABLE_STACKTRACE -may be allowed to use per-task consistency if we can come up with -another way to patch kthreads. +Unless we can come up with another way to patch kthreads, architectures +without HAVE_RELIABLE_STACKTRACE are not considered fully supported by +the kernel livepatching. The /sys/kernel/livepatch/<patch>/transition file shows whether a patch is in transition. Only a single patch (the topmost patch on the stack) @@ -176,8 +158,31 @@ If a patch is in transition, this file shows 0 to indicate the task is unpatched and 1 to indicate it's patched. Otherwise, if no patch is in transition, it shows -1. Any tasks which are blocking the transition can be signaled with SIGSTOP and SIGCONT to force them to change their -patched state. - +patched state. This may be harmful to the system though. +/sys/kernel/livepatch/<patch>/signal attribute provides a better alternative. +Writing 1 to the attribute sends a fake signal to all remaining blocking +tasks. No proper signal is actually delivered (there is no data in signal +pending structures). Tasks are interrupted or woken up, and forced to change +their patched state. + +Administrator can also affect a transition through +/sys/kernel/livepatch/<patch>/force attribute. Writing 1 there clears +TIF_PATCH_PENDING flag of all tasks and thus forces the tasks to the patched +state. Important note! The force attribute is intended for cases when the +transition gets stuck for a long time because of a blocking task. Administrator +is expected to collect all necessary data (namely stack traces of such blocking +tasks) and request a clearance from a patch distributor to force the transition. +Unauthorized usage may cause harm to the system. It depends on the nature of the +patch, which functions are (un)patched, and which functions the blocking tasks +are sleeping in (/proc/<pid>/stack may help here). Removal (rmmod) of patch +modules is permanently disabled when the force feature is used. It cannot be +guaranteed there is no task sleeping in such module. It implies unbounded +reference count if a patch module is disabled and enabled in a loop. + +Moreover, the usage of force may also affect future applications of live +patches and cause even more harm to the system. Administrator should first +consider to simply cancel a transition (see above). If force is used, reboot +should be planned and no more live patches applied. 3.1 Adding consistency model support to new architectures --------------------------------------------------------- @@ -216,13 +221,6 @@ few options: a good backup option for those architectures which don't have reliable stack traces yet. -In the meantime, patches for such architectures can bypass the -consistency model by setting klp_patch.immediate to true. This option -is perfectly fine for patches which don't change the semantics of the -patched functions. In practice, this is usable for ~90% of security -fixes. Use of this option also means the patch can't be unloaded after -it has been disabled. - 4. Livepatch module =================== @@ -278,9 +276,6 @@ into three levels: only for a particular object ( vmlinux or a kernel module ). Note that kallsyms allows for searching symbols according to the object name. - There's also an 'immediate' flag which, when set, patches the - function immediately, bypassing the consistency model safety checks. - + struct klp_object defines an array of patched functions (struct klp_func) in the same object. Where the object is either vmlinux (NULL) or a module name. @@ -299,9 +294,6 @@ into three levels: symbols are found. The only exception are symbols from objects (kernel modules) that have not been loaded yet. - Setting the 'immediate' flag applies the patch to all tasks - immediately, bypassing the consistency model safety checks. - For more details on how the patch is applied on a per-task basis, see the "Consistency model" section. @@ -316,14 +308,12 @@ section "Livepatch life-cycle" below for more details about these two operations. Module removal is only safe when there are no users of the underlying -functions. The immediate consistency model is not able to detect this. The -code just redirects the functions at the very beginning and it does not -check if the functions are in use. In other words, it knows when the -functions get called but it does not know when the functions return. -Therefore it cannot be decided when the livepatch module can be safely -removed. This is solved by a hybrid consistency model. When the system is -transitioned to a new patch state (patched/unpatched) it is guaranteed that -no task sleeps or runs in the old code. +functions. This is the reason why the force feature permanently disables +the removal. The forced tasks entered the functions but we cannot say +that they returned back. Therefore it cannot be decided when the +livepatch module can be safely removed. When the system is successfully +transitioned to a new patch state (patched/unpatched) without being +forced it is guaranteed that no task sleeps or runs in the old code. 5. Livepatch life-cycle @@ -337,19 +327,12 @@ First, the patch is applied only when all patched symbols for already loaded objects are found. The error handling is much easier if this check is done before particular functions get redirected. -Second, the immediate consistency model does not guarantee that anyone is not -sleeping in the new code after the patch is reverted. This means that the new -code needs to stay around "forever". If the code is there, one could apply it -again. Therefore it makes sense to separate the operations that might be done -once and those that need to be repeated when the patch is enabled (applied) -again. - -Third, it might take some time until the entire system is migrated -when a more complex consistency model is used. The patch revert might -block the livepatch module removal for too long. Therefore it is useful -to revert the patch using a separate operation that might be called -explicitly. But it does not make sense to remove all information -until the livepatch module is really removed. +Second, it might take some time until the entire system is migrated with +the hybrid consistency model being used. The patch revert might block +the livepatch module removal for too long. Therefore it is useful to +revert the patch using a separate operation that might be called +explicitly. But it does not make sense to remove all information until +the livepatch module is really removed. 5.1. Registration @@ -435,6 +418,9 @@ Information about the registered patches can be found under /sys/kernel/livepatch. The patches could be enabled and disabled by writing there. +/sys/kernel/livepatch/<patch>/signal and /sys/kernel/livepatch/<patch>/force +attributes allow administrator to affect a patching operation. + See Documentation/ABI/testing/sysfs-kernel-livepatch for more details. diff --git a/Documentation/networking/00-INDEX b/Documentation/networking/00-INDEX index 7a79b3587dd3..2b89d91b376f 100644 --- a/Documentation/networking/00-INDEX +++ b/Documentation/networking/00-INDEX @@ -36,8 +36,6 @@ bonding.txt - Linux Ethernet Bonding Driver HOWTO: link aggregation in Linux. bridge.txt - where to get user space programs for ethernet bridging with Linux. -can.txt - - documentation on CAN protocol family. cdc_mbim.txt - 3G/LTE USB modem (Mobile Broadband Interface Model) checksum-offloads.txt @@ -228,6 +226,8 @@ x25.txt - general info on X.25 development. x25-iface.txt - description of the X.25 Packet Layer to LAPB device interface. +xfrm_device.txt + - description of XFRM offload API xfrm_proc.txt - description of the statistics package for XFRM. xfrm_sync.txt diff --git a/Documentation/networking/batman-adv.rst b/Documentation/networking/batman-adv.rst index a342b2cc3dc6..245fb6c0ab6f 100644 --- a/Documentation/networking/batman-adv.rst +++ b/Documentation/networking/batman-adv.rst @@ -1,3 +1,5 @@ +.. SPDX-License-Identifier: GPL-2.0 + ========== batman-adv ========== diff --git a/Documentation/networking/can.rst b/Documentation/networking/can.rst new file mode 100644 index 000000000000..d23c51abf8c6 --- /dev/null +++ b/Documentation/networking/can.rst @@ -0,0 +1,1437 @@ +=================================== +SocketCAN - Controller Area Network +=================================== + +Overview / What is SocketCAN +============================ + +The socketcan package is an implementation of CAN protocols +(Controller Area Network) for Linux. CAN is a networking technology +which has widespread use in automation, embedded devices, and +automotive fields. While there have been other CAN implementations +for Linux based on character devices, SocketCAN uses the Berkeley +socket API, the Linux network stack and implements the CAN device +drivers as network interfaces. The CAN socket API has been designed +as similar as possible to the TCP/IP protocols to allow programmers, +familiar with network programming, to easily learn how to use CAN +sockets. + + +.. _socketcan-motivation: + +Motivation / Why Using the Socket API +===================================== + +There have been CAN implementations for Linux before SocketCAN so the +question arises, why we have started another project. Most existing +implementations come as a device driver for some CAN hardware, they +are based on character devices and provide comparatively little +functionality. Usually, there is only a hardware-specific device +driver which provides a character device interface to send and +receive raw CAN frames, directly to/from the controller hardware. +Queueing of frames and higher-level transport protocols like ISO-TP +have to be implemented in user space applications. Also, most +character-device implementations support only one single process to +open the device at a time, similar to a serial interface. Exchanging +the CAN controller requires employment of another device driver and +often the need for adaption of large parts of the application to the +new driver's API. + +SocketCAN was designed to overcome all of these limitations. A new +protocol family has been implemented which provides a socket interface +to user space applications and which builds upon the Linux network +layer, enabling use all of the provided queueing functionality. A device +driver for CAN controller hardware registers itself with the Linux +network layer as a network device, so that CAN frames from the +controller can be passed up to the network layer and on to the CAN +protocol family module and also vice-versa. Also, the protocol family +module provides an API for transport protocol modules to register, so +that any number of transport protocols can be loaded or unloaded +dynamically. In fact, the can core module alone does not provide any +protocol and cannot be used without loading at least one additional +protocol module. Multiple sockets can be opened at the same time, +on different or the same protocol module and they can listen/send +frames on different or the same CAN IDs. Several sockets listening on +the same interface for frames with the same CAN ID are all passed the +same received matching CAN frames. An application wishing to +communicate using a specific transport protocol, e.g. ISO-TP, just +selects that protocol when opening the socket, and then can read and +write application data byte streams, without having to deal with +CAN-IDs, frames, etc. + +Similar functionality visible from user-space could be provided by a +character device, too, but this would lead to a technically inelegant +solution for a couple of reasons: + +* **Intricate usage:** Instead of passing a protocol argument to + socket(2) and using bind(2) to select a CAN interface and CAN ID, an + application would have to do all these operations using ioctl(2)s. + +* **Code duplication:** A character device cannot make use of the Linux + network queueing code, so all that code would have to be duplicated + for CAN networking. + +* **Abstraction:** In most existing character-device implementations, the + hardware-specific device driver for a CAN controller directly + provides the character device for the application to work with. + This is at least very unusual in Unix systems for both, char and + block devices. For example you don't have a character device for a + certain UART of a serial interface, a certain sound chip in your + computer, a SCSI or IDE controller providing access to your hard + disk or tape streamer device. Instead, you have abstraction layers + which provide a unified character or block device interface to the + application on the one hand, and a interface for hardware-specific + device drivers on the other hand. These abstractions are provided + by subsystems like the tty layer, the audio subsystem or the SCSI + and IDE subsystems for the devices mentioned above. + + The easiest way to implement a CAN device driver is as a character + device without such a (complete) abstraction layer, as is done by most + existing drivers. The right way, however, would be to add such a + layer with all the functionality like registering for certain CAN + IDs, supporting several open file descriptors and (de)multiplexing + CAN frames between them, (sophisticated) queueing of CAN frames, and + providing an API for device drivers to register with. However, then + it would be no more difficult, or may be even easier, to use the + networking framework provided by the Linux kernel, and this is what + SocketCAN does. + +The use of the networking framework of the Linux kernel is just the +natural and most appropriate way to implement CAN for Linux. + + +.. _socketcan-concept: + +SocketCAN Concept +================= + +As described in :ref:`socketcan-motivation` the main goal of SocketCAN is to +provide a socket interface to user space applications which builds +upon the Linux network layer. In contrast to the commonly known +TCP/IP and ethernet networking, the CAN bus is a broadcast-only(!) +medium that has no MAC-layer addressing like ethernet. The CAN-identifier +(can_id) is used for arbitration on the CAN-bus. Therefore the CAN-IDs +have to be chosen uniquely on the bus. When designing a CAN-ECU +network the CAN-IDs are mapped to be sent by a specific ECU. +For this reason a CAN-ID can be treated best as a kind of source address. + + +.. _socketcan-receive-lists: + +Receive Lists +------------- + +The network transparent access of multiple applications leads to the +problem that different applications may be interested in the same +CAN-IDs from the same CAN network interface. The SocketCAN core +module - which implements the protocol family CAN - provides several +high efficient receive lists for this reason. If e.g. a user space +application opens a CAN RAW socket, the raw protocol module itself +requests the (range of) CAN-IDs from the SocketCAN core that are +requested by the user. The subscription and unsubscription of +CAN-IDs can be done for specific CAN interfaces or for all(!) known +CAN interfaces with the can_rx_(un)register() functions provided to +CAN protocol modules by the SocketCAN core (see :ref:`socketcan-core-module`). +To optimize the CPU usage at runtime the receive lists are split up +into several specific lists per device that match the requested +filter complexity for a given use-case. + + +.. _socketcan-local-loopback1: + +Local Loopback of Sent Frames +----------------------------- + +As known from other networking concepts the data exchanging +applications may run on the same or different nodes without any +change (except for the according addressing information): + +.. code:: + + ___ ___ ___ _______ ___ + | _ | | _ | | _ | | _ _ | | _ | + ||A|| ||B|| ||C|| ||A| |B|| ||C|| + |___| |___| |___| |_______| |___| + | | | | | + -----------------(1)- CAN bus -(2)--------------- + +To ensure that application A receives the same information in the +example (2) as it would receive in example (1) there is need for +some kind of local loopback of the sent CAN frames on the appropriate +node. + +The Linux network devices (by default) just can handle the +transmission and reception of media dependent frames. Due to the +arbitration on the CAN bus the transmission of a low prio CAN-ID +may be delayed by the reception of a high prio CAN frame. To +reflect the correct [*]_ traffic on the node the loopback of the sent +data has to be performed right after a successful transmission. If +the CAN network interface is not capable of performing the loopback for +some reason the SocketCAN core can do this task as a fallback solution. +See :ref:`socketcan-local-loopback1` for details (recommended). + +The loopback functionality is enabled by default to reflect standard +networking behaviour for CAN applications. Due to some requests from +the RT-SocketCAN group the loopback optionally may be disabled for each +separate socket. See sockopts from the CAN RAW sockets in :ref:`socketcan-raw-sockets`. + +.. [*] you really like to have this when you're running analyser + tools like 'candump' or 'cansniffer' on the (same) node. + + +.. _socketcan-network-problem-notifications: + +Network Problem Notifications +----------------------------- + +The use of the CAN bus may lead to several problems on the physical +and media access control layer. Detecting and logging of these lower +layer problems is a vital requirement for CAN users to identify +hardware issues on the physical transceiver layer as well as +arbitration problems and error frames caused by the different +ECUs. The occurrence of detected errors are important for diagnosis +and have to be logged together with the exact timestamp. For this +reason the CAN interface driver can generate so called Error Message +Frames that can optionally be passed to the user application in the +same way as other CAN frames. Whenever an error on the physical layer +or the MAC layer is detected (e.g. by the CAN controller) the driver +creates an appropriate error message frame. Error messages frames can +be requested by the user application using the common CAN filter +mechanisms. Inside this filter definition the (interested) type of +errors may be selected. The reception of error messages is disabled +by default. The format of the CAN error message frame is briefly +described in the Linux header file "include/uapi/linux/can/error.h". + + +How to use SocketCAN +==================== + +Like TCP/IP, you first need to open a socket for communicating over a +CAN network. Since SocketCAN implements a new protocol family, you +need to pass PF_CAN as the first argument to the socket(2) system +call. Currently, there are two CAN protocols to choose from, the raw +socket protocol and the broadcast manager (BCM). So to open a socket, +you would write:: + + s = socket(PF_CAN, SOCK_RAW, CAN_RAW); + +and:: + + s = socket(PF_CAN, SOCK_DGRAM, CAN_BCM); + +respectively. After the successful creation of the socket, you would +normally use the bind(2) system call to bind the socket to a CAN +interface (which is different from TCP/IP due to different addressing +- see :ref:`socketcan-concept`). After binding (CAN_RAW) or connecting (CAN_BCM) +the socket, you can read(2) and write(2) from/to the socket or use +send(2), sendto(2), sendmsg(2) and the recv* counterpart operations +on the socket as usual. There are also CAN specific socket options +described below. + +The basic CAN frame structure and the sockaddr structure are defined +in include/linux/can.h: + +.. code-block:: C + + struct can_frame { + canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */ + __u8 can_dlc; /* frame payload length in byte (0 .. 8) */ + __u8 __pad; /* padding */ + __u8 __res0; /* reserved / padding */ + __u8 __res1; /* reserved / padding */ + __u8 data[8] __attribute__((aligned(8))); + }; + +The alignment of the (linear) payload data[] to a 64bit boundary +allows the user to define their own structs and unions to easily access +the CAN payload. There is no given byteorder on the CAN bus by +default. A read(2) system call on a CAN_RAW socket transfers a +struct can_frame to the user space. + +The sockaddr_can structure has an interface index like the +PF_PACKET socket, that also binds to a specific interface: + +.. code-block:: C + + struct sockaddr_can { + sa_family_t can_family; + int can_ifindex; + union { + /* transport protocol class address info (e.g. ISOTP) */ + struct { canid_t rx_id, tx_id; } tp; + + /* reserved for future CAN protocols address information */ + } can_addr; + }; + +To determine the interface index an appropriate ioctl() has to +be used (example for CAN_RAW sockets without error checking): + +.. code-block:: C + + int s; + struct sockaddr_can addr; + struct ifreq ifr; + + s = socket(PF_CAN, SOCK_RAW, CAN_RAW); + + strcpy(ifr.ifr_name, "can0" ); + ioctl(s, SIOCGIFINDEX, &ifr); + + addr.can_family = AF_CAN; + addr.can_ifindex = ifr.ifr_ifindex; + + bind(s, (struct sockaddr *)&addr, sizeof(addr)); + + (..) + +To bind a socket to all(!) CAN interfaces the interface index must +be 0 (zero). In this case the socket receives CAN frames from every +enabled CAN interface. To determine the originating CAN interface +the system call recvfrom(2) may be used instead of read(2). To send +on a socket that is bound to 'any' interface sendto(2) is needed to +specify the outgoing interface. + +Reading CAN frames from a bound CAN_RAW socket (see above) consists +of reading a struct can_frame: + +.. code-block:: C + + struct can_frame frame; + + nbytes = read(s, &frame, sizeof(struct can_frame)); + + if (nbytes < 0) { + perror("can raw socket read"); + return 1; + } + + /* paranoid check ... */ + if (nbytes < sizeof(struct can_frame)) { + fprintf(stderr, "read: incomplete CAN frame\n"); + return 1; + } + + /* do something with the received CAN frame */ + +Writing CAN frames can be done similarly, with the write(2) system call:: + + nbytes = write(s, &frame, sizeof(struct can_frame)); + +When the CAN interface is bound to 'any' existing CAN interface +(addr.can_ifindex = 0) it is recommended to use recvfrom(2) if the +information about the originating CAN interface is needed: + +.. code-block:: C + + struct sockaddr_can addr; + struct ifreq ifr; + socklen_t len = sizeof(addr); + struct can_frame frame; + + nbytes = recvfrom(s, &frame, sizeof(struct can_frame), + 0, (struct sockaddr*)&addr, &len); + + /* get interface name of the received CAN frame */ + ifr.ifr_ifindex = addr.can_ifindex; + ioctl(s, SIOCGIFNAME, &ifr); + printf("Received a CAN frame from interface %s", ifr.ifr_name); + +To write CAN frames on sockets bound to 'any' CAN interface the +outgoing interface has to be defined certainly: + +.. code-block:: C + + strcpy(ifr.ifr_name, "can0"); + ioctl(s, SIOCGIFINDEX, &ifr); + addr.can_ifindex = ifr.ifr_ifindex; + addr.can_family = AF_CAN; + + nbytes = sendto(s, &frame, sizeof(struct can_frame), + 0, (struct sockaddr*)&addr, sizeof(addr)); + +An accurate timestamp can be obtained with an ioctl(2) call after reading +a message from the socket: + +.. code-block:: C + + struct timeval tv; + ioctl(s, SIOCGSTAMP, &tv); + +The timestamp has a resolution of one microsecond and is set automatically +at the reception of a CAN frame. + +Remark about CAN FD (flexible data rate) support: + +Generally the handling of CAN FD is very similar to the formerly described +examples. The new CAN FD capable CAN controllers support two different +bitrates for the arbitration phase and the payload phase of the CAN FD frame +and up to 64 bytes of payload. This extended payload length breaks all the +kernel interfaces (ABI) which heavily rely on the CAN frame with fixed eight +bytes of payload (struct can_frame) like the CAN_RAW socket. Therefore e.g. +the CAN_RAW socket supports a new socket option CAN_RAW_FD_FRAMES that +switches the socket into a mode that allows the handling of CAN FD frames +and (legacy) CAN frames simultaneously (see :ref:`socketcan-rawfd`). + +The struct canfd_frame is defined in include/linux/can.h: + +.. code-block:: C + + struct canfd_frame { + canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */ + __u8 len; /* frame payload length in byte (0 .. 64) */ + __u8 flags; /* additional flags for CAN FD */ + __u8 __res0; /* reserved / padding */ + __u8 __res1; /* reserved / padding */ + __u8 data[64] __attribute__((aligned(8))); + }; + +The struct canfd_frame and the existing struct can_frame have the can_id, +the payload length and the payload data at the same offset inside their +structures. This allows to handle the different structures very similar. +When the content of a struct can_frame is copied into a struct canfd_frame +all structure elements can be used as-is - only the data[] becomes extended. + +When introducing the struct canfd_frame it turned out that the data length +code (DLC) of the struct can_frame was used as a length information as the +length and the DLC has a 1:1 mapping in the range of 0 .. 8. To preserve +the easy handling of the length information the canfd_frame.len element +contains a plain length value from 0 .. 64. So both canfd_frame.len and +can_frame.can_dlc are equal and contain a length information and no DLC. +For details about the distinction of CAN and CAN FD capable devices and +the mapping to the bus-relevant data length code (DLC), see :ref:`socketcan-can-fd-driver`. + +The length of the two CAN(FD) frame structures define the maximum transfer +unit (MTU) of the CAN(FD) network interface and skbuff data length. Two +definitions are specified for CAN specific MTUs in include/linux/can.h: + +.. code-block:: C + + #define CAN_MTU (sizeof(struct can_frame)) == 16 => 'legacy' CAN frame + #define CANFD_MTU (sizeof(struct canfd_frame)) == 72 => CAN FD frame + + +.. _socketcan-raw-sockets: + +RAW Protocol Sockets with can_filters (SOCK_RAW) +------------------------------------------------ + +Using CAN_RAW sockets is extensively comparable to the commonly +known access to CAN character devices. To meet the new possibilities +provided by the multi user SocketCAN approach, some reasonable +defaults are set at RAW socket binding time: + +- The filters are set to exactly one filter receiving everything +- The socket only receives valid data frames (=> no error message frames) +- The loopback of sent CAN frames is enabled (see :ref:`socketcan-local-loopback2`) +- The socket does not receive its own sent frames (in loopback mode) + +These default settings may be changed before or after binding the socket. +To use the referenced definitions of the socket options for CAN_RAW +sockets, include <linux/can/raw.h>. + + +.. _socketcan-rawfilter: + +RAW socket option CAN_RAW_FILTER +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The reception of CAN frames using CAN_RAW sockets can be controlled +by defining 0 .. n filters with the CAN_RAW_FILTER socket option. + +The CAN filter structure is defined in include/linux/can.h: + +.. code-block:: C + + struct can_filter { + canid_t can_id; + canid_t can_mask; + }; + +A filter matches, when: + +.. code-block:: C + + <received_can_id> & mask == can_id & mask + +which is analogous to known CAN controllers hardware filter semantics. +The filter can be inverted in this semantic, when the CAN_INV_FILTER +bit is set in can_id element of the can_filter structure. In +contrast to CAN controller hardware filters the user may set 0 .. n +receive filters for each open socket separately: + +.. code-block:: C + + struct can_filter rfilter[2]; + + rfilter[0].can_id = 0x123; + rfilter[0].can_mask = CAN_SFF_MASK; + rfilter[1].can_id = 0x200; + rfilter[1].can_mask = 0x700; + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, &rfilter, sizeof(rfilter)); + +To disable the reception of CAN frames on the selected CAN_RAW socket: + +.. code-block:: C + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, NULL, 0); + +To set the filters to zero filters is quite obsolete as to not read +data causes the raw socket to discard the received CAN frames. But +having this 'send only' use-case we may remove the receive list in the +Kernel to save a little (really a very little!) CPU usage. + +CAN Filter Usage Optimisation +............................. + +The CAN filters are processed in per-device filter lists at CAN frame +reception time. To reduce the number of checks that need to be performed +while walking through the filter lists the CAN core provides an optimized +filter handling when the filter subscription focusses on a single CAN ID. + +For the possible 2048 SFF CAN identifiers the identifier is used as an index +to access the corresponding subscription list without any further checks. +For the 2^29 possible EFF CAN identifiers a 10 bit XOR folding is used as +hash function to retrieve the EFF table index. + +To benefit from the optimized filters for single CAN identifiers the +CAN_SFF_MASK or CAN_EFF_MASK have to be set into can_filter.mask together +with set CAN_EFF_FLAG and CAN_RTR_FLAG bits. A set CAN_EFF_FLAG bit in the +can_filter.mask makes clear that it matters whether a SFF or EFF CAN ID is +subscribed. E.g. in the example from above: + +.. code-block:: C + + rfilter[0].can_id = 0x123; + rfilter[0].can_mask = CAN_SFF_MASK; + +both SFF frames with CAN ID 0x123 and EFF frames with 0xXXXXX123 can pass. + +To filter for only 0x123 (SFF) and 0x12345678 (EFF) CAN identifiers the +filter has to be defined in this way to benefit from the optimized filters: + +.. code-block:: C + + struct can_filter rfilter[2]; + + rfilter[0].can_id = 0x123; + rfilter[0].can_mask = (CAN_EFF_FLAG | CAN_RTR_FLAG | CAN_SFF_MASK); + rfilter[1].can_id = 0x12345678 | CAN_EFF_FLAG; + rfilter[1].can_mask = (CAN_EFF_FLAG | CAN_RTR_FLAG | CAN_EFF_MASK); + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, &rfilter, sizeof(rfilter)); + + +RAW Socket Option CAN_RAW_ERR_FILTER +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +As described in :ref:`socketcan-network-problem-notifications` the CAN interface driver can generate so +called Error Message Frames that can optionally be passed to the user +application in the same way as other CAN frames. The possible +errors are divided into different error classes that may be filtered +using the appropriate error mask. To register for every possible +error condition CAN_ERR_MASK can be used as value for the error mask. +The values for the error mask are defined in linux/can/error.h: + +.. code-block:: C + + can_err_mask_t err_mask = ( CAN_ERR_TX_TIMEOUT | CAN_ERR_BUSOFF ); + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_ERR_FILTER, + &err_mask, sizeof(err_mask)); + + +RAW Socket Option CAN_RAW_LOOPBACK +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +To meet multi user needs the local loopback is enabled by default +(see :ref:`socketcan-local-loopback1` for details). But in some embedded use-cases +(e.g. when only one application uses the CAN bus) this loopback +functionality can be disabled (separately for each socket): + +.. code-block:: C + + int loopback = 0; /* 0 = disabled, 1 = enabled (default) */ + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_LOOPBACK, &loopback, sizeof(loopback)); + + +RAW socket option CAN_RAW_RECV_OWN_MSGS +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +When the local loopback is enabled, all the sent CAN frames are +looped back to the open CAN sockets that registered for the CAN +frames' CAN-ID on this given interface to meet the multi user +needs. The reception of the CAN frames on the same socket that was +sending the CAN frame is assumed to be unwanted and therefore +disabled by default. This default behaviour may be changed on +demand: + +.. code-block:: C + + int recv_own_msgs = 1; /* 0 = disabled (default), 1 = enabled */ + + setsockopt(s, SOL_CAN_RAW, CAN_RAW_RECV_OWN_MSGS, + &recv_own_msgs, sizeof(recv_own_msgs)); + + +.. _socketcan-rawfd: + +RAW Socket Option CAN_RAW_FD_FRAMES +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +CAN FD support in CAN_RAW sockets can be enabled with a new socket option +CAN_RAW_FD_FRAMES which is off by default. When the new socket option is +not supported by the CAN_RAW socket (e.g. on older kernels), switching the +CAN_RAW_FD_FRAMES option returns the error -ENOPROTOOPT. + +Once CAN_RAW_FD_FRAMES is enabled the application can send both CAN frames +and CAN FD frames. OTOH the application has to handle CAN and CAN FD frames +when reading from the socket: + +.. code-block:: C + + CAN_RAW_FD_FRAMES enabled: CAN_MTU and CANFD_MTU are allowed + CAN_RAW_FD_FRAMES disabled: only CAN_MTU is allowed (default) + +Example: + +.. code-block:: C + + [ remember: CANFD_MTU == sizeof(struct canfd_frame) ] + + struct canfd_frame cfd; + + nbytes = read(s, &cfd, CANFD_MTU); + + if (nbytes == CANFD_MTU) { + printf("got CAN FD frame with length %d\n", cfd.len); + /* cfd.flags contains valid data */ + } else if (nbytes == CAN_MTU) { + printf("got legacy CAN frame with length %d\n", cfd.len); + /* cfd.flags is undefined */ + } else { + fprintf(stderr, "read: invalid CAN(FD) frame\n"); + return 1; + } + + /* the content can be handled independently from the received MTU size */ + + printf("can_id: %X data length: %d data: ", cfd.can_id, cfd.len); + for (i = 0; i < cfd.len; i++) + printf("%02X ", cfd.data[i]); + +When reading with size CANFD_MTU only returns CAN_MTU bytes that have +been received from the socket a legacy CAN frame has been read into the +provided CAN FD structure. Note that the canfd_frame.flags data field is +not specified in the struct can_frame and therefore it is only valid in +CANFD_MTU sized CAN FD frames. + +Implementation hint for new CAN applications: + +To build a CAN FD aware application use struct canfd_frame as basic CAN +data structure for CAN_RAW based applications. When the application is +executed on an older Linux kernel and switching the CAN_RAW_FD_FRAMES +socket option returns an error: No problem. You'll get legacy CAN frames +or CAN FD frames and can process them the same way. + +When sending to CAN devices make sure that the device is capable to handle +CAN FD frames by checking if the device maximum transfer unit is CANFD_MTU. +The CAN device MTU can be retrieved e.g. with a SIOCGIFMTU ioctl() syscall. + + +RAW socket option CAN_RAW_JOIN_FILTERS +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The CAN_RAW socket can set multiple CAN identifier specific filters that +lead to multiple filters in the af_can.c filter processing. These filters +are indenpendent from each other which leads to logical OR'ed filters when +applied (see :ref:`socketcan-rawfilter`). + +This socket option joines the given CAN filters in the way that only CAN +frames are passed to user space that matched *all* given CAN filters. The +semantic for the applied filters is therefore changed to a logical AND. + +This is useful especially when the filterset is a combination of filters +where the CAN_INV_FILTER flag is set in order to notch single CAN IDs or +CAN ID ranges from the incoming traffic. + + +RAW Socket Returned Message Flags +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +When using recvmsg() call, the msg->msg_flags may contain following flags: + +MSG_DONTROUTE: + set when the received frame was created on the local host. + +MSG_CONFIRM: + set when the frame was sent via the socket it is received on. + This flag can be interpreted as a 'transmission confirmation' when the + CAN driver supports the echo of frames on driver level, see + :ref:`socketcan-local-loopback1` and :ref:`socketcan-local-loopback2`. + In order to receive such messages, CAN_RAW_RECV_OWN_MSGS must be set. + + +Broadcast Manager Protocol Sockets (SOCK_DGRAM) +----------------------------------------------- + +The Broadcast Manager protocol provides a command based configuration +interface to filter and send (e.g. cyclic) CAN messages in kernel space. + +Receive filters can be used to down sample frequent messages; detect events +such as message contents changes, packet length changes, and do time-out +monitoring of received messages. + +Periodic transmission tasks of CAN frames or a sequence of CAN frames can be +created and modified at runtime; both the message content and the two +possible transmit intervals can be altered. + +A BCM socket is not intended for sending individual CAN frames using the +struct can_frame as known from the CAN_RAW socket. Instead a special BCM +configuration message is defined. The basic BCM configuration message used +to communicate with the broadcast manager and the available operations are +defined in the linux/can/bcm.h include. The BCM message consists of a +message header with a command ('opcode') followed by zero or more CAN frames. +The broadcast manager sends responses to user space in the same form: + +.. code-block:: C + + struct bcm_msg_head { + __u32 opcode; /* command */ + __u32 flags; /* special flags */ + __u32 count; /* run 'count' times with ival1 */ + struct timeval ival1, ival2; /* count and subsequent interval */ + canid_t can_id; /* unique can_id for task */ + __u32 nframes; /* number of can_frames following */ + struct can_frame frames[0]; + }; + +The aligned payload 'frames' uses the same basic CAN frame structure defined +at the beginning of :ref:`socketcan-rawfd` and in the include/linux/can.h include. All +messages to the broadcast manager from user space have this structure. + +Note a CAN_BCM socket must be connected instead of bound after socket +creation (example without error checking): + +.. code-block:: C + + int s; + struct sockaddr_can addr; + struct ifreq ifr; + + s = socket(PF_CAN, SOCK_DGRAM, CAN_BCM); + + strcpy(ifr.ifr_name, "can0"); + ioctl(s, SIOCGIFINDEX, &ifr); + + addr.can_family = AF_CAN; + addr.can_ifindex = ifr.ifr_ifindex; + + connect(s, (struct sockaddr *)&addr, sizeof(addr)); + + (..) + +The broadcast manager socket is able to handle any number of in flight +transmissions or receive filters concurrently. The different RX/TX jobs are +distinguished by the unique can_id in each BCM message. However additional +CAN_BCM sockets are recommended to communicate on multiple CAN interfaces. +When the broadcast manager socket is bound to 'any' CAN interface (=> the +interface index is set to zero) the configured receive filters apply to any +CAN interface unless the sendto() syscall is used to overrule the 'any' CAN +interface index. When using recvfrom() instead of read() to retrieve BCM +socket messages the originating CAN interface is provided in can_ifindex. + + +Broadcast Manager Operations +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The opcode defines the operation for the broadcast manager to carry out, +or details the broadcast managers response to several events, including +user requests. + +Transmit Operations (user space to broadcast manager): + +TX_SETUP: + Create (cyclic) transmission task. + +TX_DELETE: + Remove (cyclic) transmission task, requires only can_id. + +TX_READ: + Read properties of (cyclic) transmission task for can_id. + +TX_SEND: + Send one CAN frame. + +Transmit Responses (broadcast manager to user space): + +TX_STATUS: + Reply to TX_READ request (transmission task configuration). + +TX_EXPIRED: + Notification when counter finishes sending at initial interval + 'ival1'. Requires the TX_COUNTEVT flag to be set at TX_SETUP. + +Receive Operations (user space to broadcast manager): + +RX_SETUP: + Create RX content filter subscription. + +RX_DELETE: + Remove RX content filter subscription, requires only can_id. + +RX_READ: + Read properties of RX content filter subscription for can_id. + +Receive Responses (broadcast manager to user space): + +RX_STATUS: + Reply to RX_READ request (filter task configuration). + +RX_TIMEOUT: + Cyclic message is detected to be absent (timer ival1 expired). + +RX_CHANGED: + BCM message with updated CAN frame (detected content change). + Sent on first message received or on receipt of revised CAN messages. + + +Broadcast Manager Message Flags +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +When sending a message to the broadcast manager the 'flags' element may +contain the following flag definitions which influence the behaviour: + +SETTIMER: + Set the values of ival1, ival2 and count + +STARTTIMER: + Start the timer with the actual values of ival1, ival2 + and count. Starting the timer leads simultaneously to emit a CAN frame. + +TX_COUNTEVT: + Create the message TX_EXPIRED when count expires + +TX_ANNOUNCE: + A change of data by the process is emitted immediately. + +TX_CP_CAN_ID: + Copies the can_id from the message header to each + subsequent frame in frames. This is intended as usage simplification. For + TX tasks the unique can_id from the message header may differ from the + can_id(s) stored for transmission in the subsequent struct can_frame(s). + +RX_FILTER_ID: + Filter by can_id alone, no frames required (nframes=0). + +RX_CHECK_DLC: + A change of the DLC leads to an RX_CHANGED. + +RX_NO_AUTOTIMER: + Prevent automatically starting the timeout monitor. + +RX_ANNOUNCE_RESUME: + If passed at RX_SETUP and a receive timeout occurred, a + RX_CHANGED message will be generated when the (cyclic) receive restarts. + +TX_RESET_MULTI_IDX: + Reset the index for the multiple frame transmission. + +RX_RTR_FRAME: + Send reply for RTR-request (placed in op->frames[0]). + + +Broadcast Manager Transmission Timers +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Periodic transmission configurations may use up to two interval timers. +In this case the BCM sends a number of messages ('count') at an interval +'ival1', then continuing to send at another given interval 'ival2'. When +only one timer is needed 'count' is set to zero and only 'ival2' is used. +When SET_TIMER and START_TIMER flag were set the timers are activated. +The timer values can be altered at runtime when only SET_TIMER is set. + + +Broadcast Manager message sequence transmission +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Up to 256 CAN frames can be transmitted in a sequence in the case of a cyclic +TX task configuration. The number of CAN frames is provided in the 'nframes' +element of the BCM message head. The defined number of CAN frames are added +as array to the TX_SETUP BCM configuration message: + +.. code-block:: C + + /* create a struct to set up a sequence of four CAN frames */ + struct { + struct bcm_msg_head msg_head; + struct can_frame frame[4]; + } mytxmsg; + + (..) + mytxmsg.msg_head.nframes = 4; + (..) + + write(s, &mytxmsg, sizeof(mytxmsg)); + +With every transmission the index in the array of CAN frames is increased +and set to zero at index overflow. + + +Broadcast Manager Receive Filter Timers +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The timer values ival1 or ival2 may be set to non-zero values at RX_SETUP. +When the SET_TIMER flag is set the timers are enabled: + +ival1: + Send RX_TIMEOUT when a received message is not received again within + the given time. When START_TIMER is set at RX_SETUP the timeout detection + is activated directly - even without a former CAN frame reception. + +ival2: + Throttle the received message rate down to the value of ival2. This + is useful to reduce messages for the application when the signal inside the + CAN frame is stateless as state changes within the ival2 periode may get + lost. + +Broadcast Manager Multiplex Message Receive Filter +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +To filter for content changes in multiplex message sequences an array of more +than one CAN frames can be passed in a RX_SETUP configuration message. The +data bytes of the first CAN frame contain the mask of relevant bits that +have to match in the subsequent CAN frames with the received CAN frame. +If one of the subsequent CAN frames is matching the bits in that frame data +mark the relevant content to be compared with the previous received content. +Up to 257 CAN frames (multiplex filter bit mask CAN frame plus 256 CAN +filters) can be added as array to the TX_SETUP BCM configuration message: + +.. code-block:: C + + /* usually used to clear CAN frame data[] - beware of endian problems! */ + #define U64_DATA(p) (*(unsigned long long*)(p)->data) + + struct { + struct bcm_msg_head msg_head; + struct can_frame frame[5]; + } msg; + + msg.msg_head.opcode = RX_SETUP; + msg.msg_head.can_id = 0x42; + msg.msg_head.flags = 0; + msg.msg_head.nframes = 5; + U64_DATA(&msg.frame[0]) = 0xFF00000000000000ULL; /* MUX mask */ + U64_DATA(&msg.frame[1]) = 0x01000000000000FFULL; /* data mask (MUX 0x01) */ + U64_DATA(&msg.frame[2]) = 0x0200FFFF000000FFULL; /* data mask (MUX 0x02) */ + U64_DATA(&msg.frame[3]) = 0x330000FFFFFF0003ULL; /* data mask (MUX 0x33) */ + U64_DATA(&msg.frame[4]) = 0x4F07FC0FF0000000ULL; /* data mask (MUX 0x4F) */ + + write(s, &msg, sizeof(msg)); + + +Broadcast Manager CAN FD Support +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The programming API of the CAN_BCM depends on struct can_frame which is +given as array directly behind the bcm_msg_head structure. To follow this +schema for the CAN FD frames a new flag 'CAN_FD_FRAME' in the bcm_msg_head +flags indicates that the concatenated CAN frame structures behind the +bcm_msg_head are defined as struct canfd_frame: + +.. code-block:: C + + struct { + struct bcm_msg_head msg_head; + struct canfd_frame frame[5]; + } msg; + + msg.msg_head.opcode = RX_SETUP; + msg.msg_head.can_id = 0x42; + msg.msg_head.flags = CAN_FD_FRAME; + msg.msg_head.nframes = 5; + (..) + +When using CAN FD frames for multiplex filtering the MUX mask is still +expected in the first 64 bit of the struct canfd_frame data section. + + +Connected Transport Protocols (SOCK_SEQPACKET) +---------------------------------------------- + +(to be written) + + +Unconnected Transport Protocols (SOCK_DGRAM) +-------------------------------------------- + +(to be written) + + +.. _socketcan-core-module: + +SocketCAN Core Module +===================== + +The SocketCAN core module implements the protocol family +PF_CAN. CAN protocol modules are loaded by the core module at +runtime. The core module provides an interface for CAN protocol +modules to subscribe needed CAN IDs (see :ref:`socketcan-receive-lists`). + + +can.ko Module Params +-------------------- + +- **stats_timer**: + To calculate the SocketCAN core statistics + (e.g. current/maximum frames per second) this 1 second timer is + invoked at can.ko module start time by default. This timer can be + disabled by using stattimer=0 on the module commandline. + +- **debug**: + (removed since SocketCAN SVN r546) + + +procfs content +-------------- + +As described in :ref:`socketcan-receive-lists` the SocketCAN core uses several filter +lists to deliver received CAN frames to CAN protocol modules. These +receive lists, their filters and the count of filter matches can be +checked in the appropriate receive list. All entries contain the +device and a protocol module identifier:: + + foo@bar:~$ cat /proc/net/can/rcvlist_all + + receive list 'rx_all': + (vcan3: no entry) + (vcan2: no entry) + (vcan1: no entry) + device can_id can_mask function userdata matches ident + vcan0 000 00000000 f88e6370 f6c6f400 0 raw + (any: no entry) + +In this example an application requests any CAN traffic from vcan0:: + + rcvlist_all - list for unfiltered entries (no filter operations) + rcvlist_eff - list for single extended frame (EFF) entries + rcvlist_err - list for error message frames masks + rcvlist_fil - list for mask/value filters + rcvlist_inv - list for mask/value filters (inverse semantic) + rcvlist_sff - list for single standard frame (SFF) entries + +Additional procfs files in /proc/net/can:: + + stats - SocketCAN core statistics (rx/tx frames, match ratios, ...) + reset_stats - manual statistic reset + version - prints the SocketCAN core version and the ABI version + + +Writing Own CAN Protocol Modules +-------------------------------- + +To implement a new protocol in the protocol family PF_CAN a new +protocol has to be defined in include/linux/can.h . +The prototypes and definitions to use the SocketCAN core can be +accessed by including include/linux/can/core.h . +In addition to functions that register the CAN protocol and the +CAN device notifier chain there are functions to subscribe CAN +frames received by CAN interfaces and to send CAN frames:: + + can_rx_register - subscribe CAN frames from a specific interface + can_rx_unregister - unsubscribe CAN frames from a specific interface + can_send - transmit a CAN frame (optional with local loopback) + +For details see the kerneldoc documentation in net/can/af_can.c or +the source code of net/can/raw.c or net/can/bcm.c . + + +CAN Network Drivers +=================== + +Writing a CAN network device driver is much easier than writing a +CAN character device driver. Similar to other known network device +drivers you mainly have to deal with: + +- TX: Put the CAN frame from the socket buffer to the CAN controller. +- RX: Put the CAN frame from the CAN controller to the socket buffer. + +See e.g. at Documentation/networking/netdevices.txt . The differences +for writing CAN network device driver are described below: + + +General Settings +---------------- + +.. code-block:: C + + dev->type = ARPHRD_CAN; /* the netdevice hardware type */ + dev->flags = IFF_NOARP; /* CAN has no arp */ + + dev->mtu = CAN_MTU; /* sizeof(struct can_frame) -> legacy CAN interface */ + + or alternative, when the controller supports CAN with flexible data rate: + dev->mtu = CANFD_MTU; /* sizeof(struct canfd_frame) -> CAN FD interface */ + +The struct can_frame or struct canfd_frame is the payload of each socket +buffer (skbuff) in the protocol family PF_CAN. + + +.. _socketcan-local-loopback2: + +Local Loopback of Sent Frames +----------------------------- + +As described in :ref:`socketcan-local-loopback1` the CAN network device driver should +support a local loopback functionality similar to the local echo +e.g. of tty devices. In this case the driver flag IFF_ECHO has to be +set to prevent the PF_CAN core from locally echoing sent frames +(aka loopback) as fallback solution:: + + dev->flags = (IFF_NOARP | IFF_ECHO); + + +CAN Controller Hardware Filters +------------------------------- + +To reduce the interrupt load on deep embedded systems some CAN +controllers support the filtering of CAN IDs or ranges of CAN IDs. +These hardware filter capabilities vary from controller to +controller and have to be identified as not feasible in a multi-user +networking approach. The use of the very controller specific +hardware filters could make sense in a very dedicated use-case, as a +filter on driver level would affect all users in the multi-user +system. The high efficient filter sets inside the PF_CAN core allow +to set different multiple filters for each socket separately. +Therefore the use of hardware filters goes to the category 'handmade +tuning on deep embedded systems'. The author is running a MPC603e +@133MHz with four SJA1000 CAN controllers from 2002 under heavy bus +load without any problems ... + + +The Virtual CAN Driver (vcan) +----------------------------- + +Similar to the network loopback devices, vcan offers a virtual local +CAN interface. A full qualified address on CAN consists of + +- a unique CAN Identifier (CAN ID) +- the CAN bus this CAN ID is transmitted on (e.g. can0) + +so in common use cases more than one virtual CAN interface is needed. + +The virtual CAN interfaces allow the transmission and reception of CAN +frames without real CAN controller hardware. Virtual CAN network +devices are usually named 'vcanX', like vcan0 vcan1 vcan2 ... +When compiled as a module the virtual CAN driver module is called vcan.ko + +Since Linux Kernel version 2.6.24 the vcan driver supports the Kernel +netlink interface to create vcan network devices. The creation and +removal of vcan network devices can be managed with the ip(8) tool:: + + - Create a virtual CAN network interface: + $ ip link add type vcan + + - Create a virtual CAN network interface with a specific name 'vcan42': + $ ip link add dev vcan42 type vcan + + - Remove a (virtual CAN) network interface 'vcan42': + $ ip link del vcan42 + + +The CAN Network Device Driver Interface +--------------------------------------- + +The CAN network device driver interface provides a generic interface +to setup, configure and monitor CAN network devices. The user can then +configure the CAN device, like setting the bit-timing parameters, via +the netlink interface using the program "ip" from the "IPROUTE2" +utility suite. The following chapter describes briefly how to use it. +Furthermore, the interface uses a common data structure and exports a +set of common functions, which all real CAN network device drivers +should use. Please have a look to the SJA1000 or MSCAN driver to +understand how to use them. The name of the module is can-dev.ko. + + +Netlink interface to set/get devices properties +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The CAN device must be configured via netlink interface. The supported +netlink message types are defined and briefly described in +"include/linux/can/netlink.h". CAN link support for the program "ip" +of the IPROUTE2 utility suite is available and it can be used as shown +below: + +Setting CAN device properties:: + + $ ip link set can0 type can help + Usage: ip link set DEVICE type can + [ bitrate BITRATE [ sample-point SAMPLE-POINT] ] | + [ tq TQ prop-seg PROP_SEG phase-seg1 PHASE-SEG1 + phase-seg2 PHASE-SEG2 [ sjw SJW ] ] + + [ dbitrate BITRATE [ dsample-point SAMPLE-POINT] ] | + [ dtq TQ dprop-seg PROP_SEG dphase-seg1 PHASE-SEG1 + dphase-seg2 PHASE-SEG2 [ dsjw SJW ] ] + + [ loopback { on | off } ] + [ listen-only { on | off } ] + [ triple-sampling { on | off } ] + [ one-shot { on | off } ] + [ berr-reporting { on | off } ] + [ fd { on | off } ] + [ fd-non-iso { on | off } ] + [ presume-ack { on | off } ] + + [ restart-ms TIME-MS ] + [ restart ] + + Where: BITRATE := { 1..1000000 } + SAMPLE-POINT := { 0.000..0.999 } + TQ := { NUMBER } + PROP-SEG := { 1..8 } + PHASE-SEG1 := { 1..8 } + PHASE-SEG2 := { 1..8 } + SJW := { 1..4 } + RESTART-MS := { 0 | NUMBER } + +Display CAN device details and statistics:: + + $ ip -details -statistics link show can0 + 2: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UP qlen 10 + link/can + can <TRIPLE-SAMPLING> state ERROR-ACTIVE restart-ms 100 + bitrate 125000 sample_point 0.875 + tq 125 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1 + sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1 + clock 8000000 + re-started bus-errors arbit-lost error-warn error-pass bus-off + 41 17457 0 41 42 41 + RX: bytes packets errors dropped overrun mcast + 140859 17608 17457 0 0 0 + TX: bytes packets errors dropped carrier collsns + 861 112 0 41 0 0 + +More info to the above output: + +"<TRIPLE-SAMPLING>" + Shows the list of selected CAN controller modes: LOOPBACK, + LISTEN-ONLY, or TRIPLE-SAMPLING. + +"state ERROR-ACTIVE" + The current state of the CAN controller: "ERROR-ACTIVE", + "ERROR-WARNING", "ERROR-PASSIVE", "BUS-OFF" or "STOPPED" + +"restart-ms 100" + Automatic restart delay time. If set to a non-zero value, a + restart of the CAN controller will be triggered automatically + in case of a bus-off condition after the specified delay time + in milliseconds. By default it's off. + +"bitrate 125000 sample-point 0.875" + Shows the real bit-rate in bits/sec and the sample-point in the + range 0.000..0.999. If the calculation of bit-timing parameters + is enabled in the kernel (CONFIG_CAN_CALC_BITTIMING=y), the + bit-timing can be defined by setting the "bitrate" argument. + Optionally the "sample-point" can be specified. By default it's + 0.000 assuming CIA-recommended sample-points. + +"tq 125 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1" + Shows the time quanta in ns, propagation segment, phase buffer + segment 1 and 2 and the synchronisation jump width in units of + tq. They allow to define the CAN bit-timing in a hardware + independent format as proposed by the Bosch CAN 2.0 spec (see + chapter 8 of http://www.semiconductors.bosch.de/pdf/can2spec.pdf). + +"sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1 clock 8000000" + Shows the bit-timing constants of the CAN controller, here the + "sja1000". The minimum and maximum values of the time segment 1 + and 2, the synchronisation jump width in units of tq, the + bitrate pre-scaler and the CAN system clock frequency in Hz. + These constants could be used for user-defined (non-standard) + bit-timing calculation algorithms in user-space. + +"re-started bus-errors arbit-lost error-warn error-pass bus-off" + Shows the number of restarts, bus and arbitration lost errors, + and the state changes to the error-warning, error-passive and + bus-off state. RX overrun errors are listed in the "overrun" + field of the standard network statistics. + +Setting the CAN Bit-Timing +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The CAN bit-timing parameters can always be defined in a hardware +independent format as proposed in the Bosch CAN 2.0 specification +specifying the arguments "tq", "prop_seg", "phase_seg1", "phase_seg2" +and "sjw":: + + $ ip link set canX type can tq 125 prop-seg 6 \ + phase-seg1 7 phase-seg2 2 sjw 1 + +If the kernel option CONFIG_CAN_CALC_BITTIMING is enabled, CIA +recommended CAN bit-timing parameters will be calculated if the bit- +rate is specified with the argument "bitrate":: + + $ ip link set canX type can bitrate 125000 + +Note that this works fine for the most common CAN controllers with +standard bit-rates but may *fail* for exotic bit-rates or CAN system +clock frequencies. Disabling CONFIG_CAN_CALC_BITTIMING saves some +space and allows user-space tools to solely determine and set the +bit-timing parameters. The CAN controller specific bit-timing +constants can be used for that purpose. They are listed by the +following command:: + + $ ip -details link show can0 + ... + sja1000: clock 8000000 tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1 + + +Starting and Stopping the CAN Network Device +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +A CAN network device is started or stopped as usual with the command +"ifconfig canX up/down" or "ip link set canX up/down". Be aware that +you *must* define proper bit-timing parameters for real CAN devices +before you can start it to avoid error-prone default settings:: + + $ ip link set canX up type can bitrate 125000 + +A device may enter the "bus-off" state if too many errors occurred on +the CAN bus. Then no more messages are received or sent. An automatic +bus-off recovery can be enabled by setting the "restart-ms" to a +non-zero value, e.g.:: + + $ ip link set canX type can restart-ms 100 + +Alternatively, the application may realize the "bus-off" condition +by monitoring CAN error message frames and do a restart when +appropriate with the command:: + + $ ip link set canX type can restart + +Note that a restart will also create a CAN error message frame (see +also :ref:`socketcan-network-problem-notifications`). + + +.. _socketcan-can-fd-driver: + +CAN FD (Flexible Data Rate) Driver Support +------------------------------------------ + +CAN FD capable CAN controllers support two different bitrates for the +arbitration phase and the payload phase of the CAN FD frame. Therefore a +second bit timing has to be specified in order to enable the CAN FD bitrate. + +Additionally CAN FD capable CAN controllers support up to 64 bytes of +payload. The representation of this length in can_frame.can_dlc and +canfd_frame.len for userspace applications and inside the Linux network +layer is a plain value from 0 .. 64 instead of the CAN 'data length code'. +The data length code was a 1:1 mapping to the payload length in the legacy +CAN frames anyway. The payload length to the bus-relevant DLC mapping is +only performed inside the CAN drivers, preferably with the helper +functions can_dlc2len() and can_len2dlc(). + +The CAN netdevice driver capabilities can be distinguished by the network +devices maximum transfer unit (MTU):: + + MTU = 16 (CAN_MTU) => sizeof(struct can_frame) => 'legacy' CAN device + MTU = 72 (CANFD_MTU) => sizeof(struct canfd_frame) => CAN FD capable device + +The CAN device MTU can be retrieved e.g. with a SIOCGIFMTU ioctl() syscall. +N.B. CAN FD capable devices can also handle and send legacy CAN frames. + +When configuring CAN FD capable CAN controllers an additional 'data' bitrate +has to be set. This bitrate for the data phase of the CAN FD frame has to be +at least the bitrate which was configured for the arbitration phase. This +second bitrate is specified analogue to the first bitrate but the bitrate +setting keywords for the 'data' bitrate start with 'd' e.g. dbitrate, +dsample-point, dsjw or dtq and similar settings. When a data bitrate is set +within the configuration process the controller option "fd on" can be +specified to enable the CAN FD mode in the CAN controller. This controller +option also switches the device MTU to 72 (CANFD_MTU). + +The first CAN FD specification presented as whitepaper at the International +CAN Conference 2012 needed to be improved for data integrity reasons. +Therefore two CAN FD implementations have to be distinguished today: + +- ISO compliant: The ISO 11898-1:2015 CAN FD implementation (default) +- non-ISO compliant: The CAN FD implementation following the 2012 whitepaper + +Finally there are three types of CAN FD controllers: + +1. ISO compliant (fixed) +2. non-ISO compliant (fixed, like the M_CAN IP core v3.0.1 in m_can.c) +3. ISO/non-ISO CAN FD controllers (switchable, like the PEAK PCAN-USB FD) + +The current ISO/non-ISO mode is announced by the CAN controller driver via +netlink and displayed by the 'ip' tool (controller option FD-NON-ISO). +The ISO/non-ISO-mode can be altered by setting 'fd-non-iso {on|off}' for +switchable CAN FD controllers only. + +Example configuring 500 kbit/s arbitration bitrate and 4 Mbit/s data bitrate:: + + $ ip link set can0 up type can bitrate 500000 sample-point 0.75 \ + dbitrate 4000000 dsample-point 0.8 fd on + $ ip -details link show can0 + 5: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 72 qdisc pfifo_fast state UNKNOWN \ + mode DEFAULT group default qlen 10 + link/can promiscuity 0 + can <FD> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 + bitrate 500000 sample-point 0.750 + tq 50 prop-seg 14 phase-seg1 15 phase-seg2 10 sjw 1 + pcan_usb_pro_fd: tseg1 1..64 tseg2 1..16 sjw 1..16 brp 1..1024 \ + brp-inc 1 + dbitrate 4000000 dsample-point 0.800 + dtq 12 dprop-seg 7 dphase-seg1 8 dphase-seg2 4 dsjw 1 + pcan_usb_pro_fd: dtseg1 1..16 dtseg2 1..8 dsjw 1..4 dbrp 1..1024 \ + dbrp-inc 1 + clock 80000000 + +Example when 'fd-non-iso on' is added on this switchable CAN FD adapter:: + + can <FD,FD-NON-ISO> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 + + +Supported CAN Hardware +---------------------- + +Please check the "Kconfig" file in "drivers/net/can" to get an actual +list of the support CAN hardware. On the SocketCAN project website +(see :ref:`socketcan-resources`) there might be further drivers available, also for +older kernel versions. + + +.. _socketcan-resources: + +SocketCAN Resources +=================== + +The Linux CAN / SocketCAN project resources (project site / mailing list) +are referenced in the MAINTAINERS file in the Linux source tree. +Search for CAN NETWORK [LAYERS|DRIVERS]. + +Credits +======= + +- Oliver Hartkopp (PF_CAN core, filters, drivers, bcm, SJA1000 driver) +- Urs Thuermann (PF_CAN core, kernel integration, socket interfaces, raw, vcan) +- Jan Kizka (RT-SocketCAN core, Socket-API reconciliation) +- Wolfgang Grandegger (RT-SocketCAN core & drivers, Raw Socket-API reviews, CAN device driver interface, MSCAN driver) +- Robert Schwebel (design reviews, PTXdist integration) +- Marc Kleine-Budde (design reviews, Kernel 2.6 cleanups, drivers) +- Benedikt Spranger (reviews) +- Thomas Gleixner (LKML reviews, coding style, posting hints) +- Andrey Volkov (kernel subtree structure, ioctls, MSCAN driver) +- Matthias Brukner (first SJA1000 CAN netdevice implementation Q2/2003) +- Klaus Hitschler (PEAK driver integration) +- Uwe Koppe (CAN netdevices with PF_PACKET approach) +- Michael Schulze (driver layer loopback requirement, RT CAN drivers review) +- Pavel Pisa (Bit-timing calculation) +- Sascha Hauer (SJA1000 platform driver) +- Sebastian Haas (SJA1000 EMS PCI driver) +- Markus Plessing (SJA1000 EMS PCI driver) +- Per Dalen (SJA1000 Kvaser PCI driver) +- Sam Ravnborg (reviews, coding style, kbuild help) diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt deleted file mode 100644 index aa15b9ee2e70..000000000000 --- a/Documentation/networking/can.txt +++ /dev/null @@ -1,1308 +0,0 @@ -============================================================================ - -can.txt - -Readme file for the Controller Area Network Protocol Family (aka SocketCAN) - -This file contains - - 1 Overview / What is SocketCAN - - 2 Motivation / Why using the socket API - - 3 SocketCAN concept - 3.1 receive lists - 3.2 local loopback of sent frames - 3.3 network problem notifications - - 4 How to use SocketCAN - 4.1 RAW protocol sockets with can_filters (SOCK_RAW) - 4.1.1 RAW socket option CAN_RAW_FILTER - 4.1.2 RAW socket option CAN_RAW_ERR_FILTER - 4.1.3 RAW socket option CAN_RAW_LOOPBACK - 4.1.4 RAW socket option CAN_RAW_RECV_OWN_MSGS - 4.1.5 RAW socket option CAN_RAW_FD_FRAMES - 4.1.6 RAW socket option CAN_RAW_JOIN_FILTERS - 4.1.7 RAW socket returned message flags - 4.2 Broadcast Manager protocol sockets (SOCK_DGRAM) - 4.2.1 Broadcast Manager operations - 4.2.2 Broadcast Manager message flags - 4.2.3 Broadcast Manager transmission timers - 4.2.4 Broadcast Manager message sequence transmission - 4.2.5 Broadcast Manager receive filter timers - 4.2.6 Broadcast Manager multiplex message receive filter - 4.2.7 Broadcast Manager CAN FD support - 4.3 connected transport protocols (SOCK_SEQPACKET) - 4.4 unconnected transport protocols (SOCK_DGRAM) - - 5 SocketCAN core module - 5.1 can.ko module params - 5.2 procfs content - 5.3 writing own CAN protocol modules - - 6 CAN network drivers - 6.1 general settings - 6.2 local loopback of sent frames - 6.3 CAN controller hardware filters - 6.4 The virtual CAN driver (vcan) - 6.5 The CAN network device driver interface - 6.5.1 Netlink interface to set/get devices properties - 6.5.2 Setting the CAN bit-timing - 6.5.3 Starting and stopping the CAN network device - 6.6 CAN FD (flexible data rate) driver support - 6.7 supported CAN hardware - - 7 SocketCAN resources - - 8 Credits - -============================================================================ - -1. Overview / What is SocketCAN --------------------------------- - -The socketcan package is an implementation of CAN protocols -(Controller Area Network) for Linux. CAN is a networking technology -which has widespread use in automation, embedded devices, and -automotive fields. While there have been other CAN implementations -for Linux based on character devices, SocketCAN uses the Berkeley -socket API, the Linux network stack and implements the CAN device -drivers as network interfaces. The CAN socket API has been designed -as similar as possible to the TCP/IP protocols to allow programmers, -familiar with network programming, to easily learn how to use CAN -sockets. - -2. Motivation / Why using the socket API ----------------------------------------- - -There have been CAN implementations for Linux before SocketCAN so the -question arises, why we have started another project. Most existing -implementations come as a device driver for some CAN hardware, they -are based on character devices and provide comparatively little -functionality. Usually, there is only a hardware-specific device -driver which provides a character device interface to send and -receive raw CAN frames, directly to/from the controller hardware. -Queueing of frames and higher-level transport protocols like ISO-TP -have to be implemented in user space applications. Also, most -character-device implementations support only one single process to -open the device at a time, similar to a serial interface. Exchanging -the CAN controller requires employment of another device driver and -often the need for adaption of large parts of the application to the -new driver's API. - -SocketCAN was designed to overcome all of these limitations. A new -protocol family has been implemented which provides a socket interface -to user space applications and which builds upon the Linux network -layer, enabling use all of the provided queueing functionality. A device -driver for CAN controller hardware registers itself with the Linux -network layer as a network device, so that CAN frames from the -controller can be passed up to the network layer and on to the CAN -protocol family module and also vice-versa. Also, the protocol family -module provides an API for transport protocol modules to register, so -that any number of transport protocols can be loaded or unloaded -dynamically. In fact, the can core module alone does not provide any -protocol and cannot be used without loading at least one additional -protocol module. Multiple sockets can be opened at the same time, -on different or the same protocol module and they can listen/send -frames on different or the same CAN IDs. Several sockets listening on -the same interface for frames with the same CAN ID are all passed the -same received matching CAN frames. An application wishing to -communicate using a specific transport protocol, e.g. ISO-TP, just -selects that protocol when opening the socket, and then can read and -write application data byte streams, without having to deal with -CAN-IDs, frames, etc. - -Similar functionality visible from user-space could be provided by a -character device, too, but this would lead to a technically inelegant -solution for a couple of reasons: - -* Intricate usage. Instead of passing a protocol argument to - socket(2) and using bind(2) to select a CAN interface and CAN ID, an - application would have to do all these operations using ioctl(2)s. - -* Code duplication. A character device cannot make use of the Linux - network queueing code, so all that code would have to be duplicated - for CAN networking. - -* Abstraction. In most existing character-device implementations, the - hardware-specific device driver for a CAN controller directly - provides the character device for the application to work with. - This is at least very unusual in Unix systems for both, char and - block devices. For example you don't have a character device for a - certain UART of a serial interface, a certain sound chip in your - computer, a SCSI or IDE controller providing access to your hard - disk or tape streamer device. Instead, you have abstraction layers - which provide a unified character or block device interface to the - application on the one hand, and a interface for hardware-specific - device drivers on the other hand. These abstractions are provided - by subsystems like the tty layer, the audio subsystem or the SCSI - and IDE subsystems for the devices mentioned above. - - The easiest way to implement a CAN device driver is as a character - device without such a (complete) abstraction layer, as is done by most - existing drivers. The right way, however, would be to add such a - layer with all the functionality like registering for certain CAN - IDs, supporting several open file descriptors and (de)multiplexing - CAN frames between them, (sophisticated) queueing of CAN frames, and - providing an API for device drivers to register with. However, then - it would be no more difficult, or may be even easier, to use the - networking framework provided by the Linux kernel, and this is what - SocketCAN does. - - The use of the networking framework of the Linux kernel is just the - natural and most appropriate way to implement CAN for Linux. - -3. SocketCAN concept ---------------------- - - As described in chapter 2 it is the main goal of SocketCAN to - provide a socket interface to user space applications which builds - upon the Linux network layer. In contrast to the commonly known - TCP/IP and ethernet networking, the CAN bus is a broadcast-only(!) - medium that has no MAC-layer addressing like ethernet. The CAN-identifier - (can_id) is used for arbitration on the CAN-bus. Therefore the CAN-IDs - have to be chosen uniquely on the bus. When designing a CAN-ECU - network the CAN-IDs are mapped to be sent by a specific ECU. - For this reason a CAN-ID can be treated best as a kind of source address. - - 3.1 receive lists - - The network transparent access of multiple applications leads to the - problem that different applications may be interested in the same - CAN-IDs from the same CAN network interface. The SocketCAN core - module - which implements the protocol family CAN - provides several - high efficient receive lists for this reason. If e.g. a user space - application opens a CAN RAW socket, the raw protocol module itself - requests the (range of) CAN-IDs from the SocketCAN core that are - requested by the user. The subscription and unsubscription of - CAN-IDs can be done for specific CAN interfaces or for all(!) known - CAN interfaces with the can_rx_(un)register() functions provided to - CAN protocol modules by the SocketCAN core (see chapter 5). - To optimize the CPU usage at runtime the receive lists are split up - into several specific lists per device that match the requested - filter complexity for a given use-case. - - 3.2 local loopback of sent frames - - As known from other networking concepts the data exchanging - applications may run on the same or different nodes without any - change (except for the according addressing information): - - ___ ___ ___ _______ ___ - | _ | | _ | | _ | | _ _ | | _ | - ||A|| ||B|| ||C|| ||A| |B|| ||C|| - |___| |___| |___| |_______| |___| - | | | | | - -----------------(1)- CAN bus -(2)--------------- - - To ensure that application A receives the same information in the - example (2) as it would receive in example (1) there is need for - some kind of local loopback of the sent CAN frames on the appropriate - node. - - The Linux network devices (by default) just can handle the - transmission and reception of media dependent frames. Due to the - arbitration on the CAN bus the transmission of a low prio CAN-ID - may be delayed by the reception of a high prio CAN frame. To - reflect the correct* traffic on the node the loopback of the sent - data has to be performed right after a successful transmission. If - the CAN network interface is not capable of performing the loopback for - some reason the SocketCAN core can do this task as a fallback solution. - See chapter 6.2 for details (recommended). - - The loopback functionality is enabled by default to reflect standard - networking behaviour for CAN applications. Due to some requests from - the RT-SocketCAN group the loopback optionally may be disabled for each - separate socket. See sockopts from the CAN RAW sockets in chapter 4.1. - - * = you really like to have this when you're running analyser tools - like 'candump' or 'cansniffer' on the (same) node. - - 3.3 network problem notifications - - The use of the CAN bus may lead to several problems on the physical - and media access control layer. Detecting and logging of these lower - layer problems is a vital requirement for CAN users to identify - hardware issues on the physical transceiver layer as well as - arbitration problems and error frames caused by the different - ECUs. The occurrence of detected errors are important for diagnosis - and have to be logged together with the exact timestamp. For this - reason the CAN interface driver can generate so called Error Message - Frames that can optionally be passed to the user application in the - same way as other CAN frames. Whenever an error on the physical layer - or the MAC layer is detected (e.g. by the CAN controller) the driver - creates an appropriate error message frame. Error messages frames can - be requested by the user application using the common CAN filter - mechanisms. Inside this filter definition the (interested) type of - errors may be selected. The reception of error messages is disabled - by default. The format of the CAN error message frame is briefly - described in the Linux header file "include/uapi/linux/can/error.h". - -4. How to use SocketCAN ------------------------- - - Like TCP/IP, you first need to open a socket for communicating over a - CAN network. Since SocketCAN implements a new protocol family, you - need to pass PF_CAN as the first argument to the socket(2) system - call. Currently, there are two CAN protocols to choose from, the raw - socket protocol and the broadcast manager (BCM). So to open a socket, - you would write - - s = socket(PF_CAN, SOCK_RAW, CAN_RAW); - - and - - s = socket(PF_CAN, SOCK_DGRAM, CAN_BCM); - - respectively. After the successful creation of the socket, you would - normally use the bind(2) system call to bind the socket to a CAN - interface (which is different from TCP/IP due to different addressing - - see chapter 3). After binding (CAN_RAW) or connecting (CAN_BCM) - the socket, you can read(2) and write(2) from/to the socket or use - send(2), sendto(2), sendmsg(2) and the recv* counterpart operations - on the socket as usual. There are also CAN specific socket options - described below. - - The basic CAN frame structure and the sockaddr structure are defined - in include/linux/can.h: - - struct can_frame { - canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */ - __u8 can_dlc; /* frame payload length in byte (0 .. 8) */ - __u8 __pad; /* padding */ - __u8 __res0; /* reserved / padding */ - __u8 __res1; /* reserved / padding */ - __u8 data[8] __attribute__((aligned(8))); - }; - - The alignment of the (linear) payload data[] to a 64bit boundary - allows the user to define their own structs and unions to easily access - the CAN payload. There is no given byteorder on the CAN bus by - default. A read(2) system call on a CAN_RAW socket transfers a - struct can_frame to the user space. - - The sockaddr_can structure has an interface index like the - PF_PACKET socket, that also binds to a specific interface: - - struct sockaddr_can { - sa_family_t can_family; - int can_ifindex; - union { - /* transport protocol class address info (e.g. ISOTP) */ - struct { canid_t rx_id, tx_id; } tp; - - /* reserved for future CAN protocols address information */ - } can_addr; - }; - - To determine the interface index an appropriate ioctl() has to - be used (example for CAN_RAW sockets without error checking): - - int s; - struct sockaddr_can addr; - struct ifreq ifr; - - s = socket(PF_CAN, SOCK_RAW, CAN_RAW); - - strcpy(ifr.ifr_name, "can0" ); - ioctl(s, SIOCGIFINDEX, &ifr); - - addr.can_family = AF_CAN; - addr.can_ifindex = ifr.ifr_ifindex; - - bind(s, (struct sockaddr *)&addr, sizeof(addr)); - - (..) - - To bind a socket to all(!) CAN interfaces the interface index must - be 0 (zero). In this case the socket receives CAN frames from every - enabled CAN interface. To determine the originating CAN interface - the system call recvfrom(2) may be used instead of read(2). To send - on a socket that is bound to 'any' interface sendto(2) is needed to - specify the outgoing interface. - - Reading CAN frames from a bound CAN_RAW socket (see above) consists - of reading a struct can_frame: - - struct can_frame frame; - - nbytes = read(s, &frame, sizeof(struct can_frame)); - - if (nbytes < 0) { - perror("can raw socket read"); - return 1; - } - - /* paranoid check ... */ - if (nbytes < sizeof(struct can_frame)) { - fprintf(stderr, "read: incomplete CAN frame\n"); - return 1; - } - - /* do something with the received CAN frame */ - - Writing CAN frames can be done similarly, with the write(2) system call: - - nbytes = write(s, &frame, sizeof(struct can_frame)); - - When the CAN interface is bound to 'any' existing CAN interface - (addr.can_ifindex = 0) it is recommended to use recvfrom(2) if the - information about the originating CAN interface is needed: - - struct sockaddr_can addr; - struct ifreq ifr; - socklen_t len = sizeof(addr); - struct can_frame frame; - - nbytes = recvfrom(s, &frame, sizeof(struct can_frame), - 0, (struct sockaddr*)&addr, &len); - - /* get interface name of the received CAN frame */ - ifr.ifr_ifindex = addr.can_ifindex; - ioctl(s, SIOCGIFNAME, &ifr); - printf("Received a CAN frame from interface %s", ifr.ifr_name); - - To write CAN frames on sockets bound to 'any' CAN interface the - outgoing interface has to be defined certainly. - - strcpy(ifr.ifr_name, "can0"); - ioctl(s, SIOCGIFINDEX, &ifr); - addr.can_ifindex = ifr.ifr_ifindex; - addr.can_family = AF_CAN; - - nbytes = sendto(s, &frame, sizeof(struct can_frame), - 0, (struct sockaddr*)&addr, sizeof(addr)); - - An accurate timestamp can be obtained with an ioctl(2) call after reading - a message from the socket: - - struct timeval tv; - ioctl(s, SIOCGSTAMP, &tv); - - The timestamp has a resolution of one microsecond and is set automatically - at the reception of a CAN frame. - - Remark about CAN FD (flexible data rate) support: - - Generally the handling of CAN FD is very similar to the formerly described - examples. The new CAN FD capable CAN controllers support two different - bitrates for the arbitration phase and the payload phase of the CAN FD frame - and up to 64 bytes of payload. This extended payload length breaks all the - kernel interfaces (ABI) which heavily rely on the CAN frame with fixed eight - bytes of payload (struct can_frame) like the CAN_RAW socket. Therefore e.g. - the CAN_RAW socket supports a new socket option CAN_RAW_FD_FRAMES that - switches the socket into a mode that allows the handling of CAN FD frames - and (legacy) CAN frames simultaneously (see section 4.1.5). - - The struct canfd_frame is defined in include/linux/can.h: - - struct canfd_frame { - canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */ - __u8 len; /* frame payload length in byte (0 .. 64) */ - __u8 flags; /* additional flags for CAN FD */ - __u8 __res0; /* reserved / padding */ - __u8 __res1; /* reserved / padding */ - __u8 data[64] __attribute__((aligned(8))); - }; - - The struct canfd_frame and the existing struct can_frame have the can_id, - the payload length and the payload data at the same offset inside their - structures. This allows to handle the different structures very similar. - When the content of a struct can_frame is copied into a struct canfd_frame - all structure elements can be used as-is - only the data[] becomes extended. - - When introducing the struct canfd_frame it turned out that the data length - code (DLC) of the struct can_frame was used as a length information as the - length and the DLC has a 1:1 mapping in the range of 0 .. 8. To preserve - the easy handling of the length information the canfd_frame.len element - contains a plain length value from 0 .. 64. So both canfd_frame.len and - can_frame.can_dlc are equal and contain a length information and no DLC. - For details about the distinction of CAN and CAN FD capable devices and - the mapping to the bus-relevant data length code (DLC), see chapter 6.6. - - The length of the two CAN(FD) frame structures define the maximum transfer - unit (MTU) of the CAN(FD) network interface and skbuff data length. Two - definitions are specified for CAN specific MTUs in include/linux/can.h : - - #define CAN_MTU (sizeof(struct can_frame)) == 16 => 'legacy' CAN frame - #define CANFD_MTU (sizeof(struct canfd_frame)) == 72 => CAN FD frame - - 4.1 RAW protocol sockets with can_filters (SOCK_RAW) - - Using CAN_RAW sockets is extensively comparable to the commonly - known access to CAN character devices. To meet the new possibilities - provided by the multi user SocketCAN approach, some reasonable - defaults are set at RAW socket binding time: - - - The filters are set to exactly one filter receiving everything - - The socket only receives valid data frames (=> no error message frames) - - The loopback of sent CAN frames is enabled (see chapter 3.2) - - The socket does not receive its own sent frames (in loopback mode) - - These default settings may be changed before or after binding the socket. - To use the referenced definitions of the socket options for CAN_RAW - sockets, include <linux/can/raw.h>. - - 4.1.1 RAW socket option CAN_RAW_FILTER - - The reception of CAN frames using CAN_RAW sockets can be controlled - by defining 0 .. n filters with the CAN_RAW_FILTER socket option. - - The CAN filter structure is defined in include/linux/can.h: - - struct can_filter { - canid_t can_id; - canid_t can_mask; - }; - - A filter matches, when - - <received_can_id> & mask == can_id & mask - - which is analogous to known CAN controllers hardware filter semantics. - The filter can be inverted in this semantic, when the CAN_INV_FILTER - bit is set in can_id element of the can_filter structure. In - contrast to CAN controller hardware filters the user may set 0 .. n - receive filters for each open socket separately: - - struct can_filter rfilter[2]; - - rfilter[0].can_id = 0x123; - rfilter[0].can_mask = CAN_SFF_MASK; - rfilter[1].can_id = 0x200; - rfilter[1].can_mask = 0x700; - - setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, &rfilter, sizeof(rfilter)); - - To disable the reception of CAN frames on the selected CAN_RAW socket: - - setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, NULL, 0); - - To set the filters to zero filters is quite obsolete as to not read - data causes the raw socket to discard the received CAN frames. But - having this 'send only' use-case we may remove the receive list in the - Kernel to save a little (really a very little!) CPU usage. - - 4.1.1.1 CAN filter usage optimisation - - The CAN filters are processed in per-device filter lists at CAN frame - reception time. To reduce the number of checks that need to be performed - while walking through the filter lists the CAN core provides an optimized - filter handling when the filter subscription focusses on a single CAN ID. - - For the possible 2048 SFF CAN identifiers the identifier is used as an index - to access the corresponding subscription list without any further checks. - For the 2^29 possible EFF CAN identifiers a 10 bit XOR folding is used as - hash function to retrieve the EFF table index. - - To benefit from the optimized filters for single CAN identifiers the - CAN_SFF_MASK or CAN_EFF_MASK have to be set into can_filter.mask together - with set CAN_EFF_FLAG and CAN_RTR_FLAG bits. A set CAN_EFF_FLAG bit in the - can_filter.mask makes clear that it matters whether a SFF or EFF CAN ID is - subscribed. E.g. in the example from above - - rfilter[0].can_id = 0x123; - rfilter[0].can_mask = CAN_SFF_MASK; - - both SFF frames with CAN ID 0x123 and EFF frames with 0xXXXXX123 can pass. - - To filter for only 0x123 (SFF) and 0x12345678 (EFF) CAN identifiers the - filter has to be defined in this way to benefit from the optimized filters: - - struct can_filter rfilter[2]; - - rfilter[0].can_id = 0x123; - rfilter[0].can_mask = (CAN_EFF_FLAG | CAN_RTR_FLAG | CAN_SFF_MASK); - rfilter[1].can_id = 0x12345678 | CAN_EFF_FLAG; - rfilter[1].can_mask = (CAN_EFF_FLAG | CAN_RTR_FLAG | CAN_EFF_MASK); - - setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, &rfilter, sizeof(rfilter)); - - 4.1.2 RAW socket option CAN_RAW_ERR_FILTER - - As described in chapter 3.3 the CAN interface driver can generate so - called Error Message Frames that can optionally be passed to the user - application in the same way as other CAN frames. The possible - errors are divided into different error classes that may be filtered - using the appropriate error mask. To register for every possible - error condition CAN_ERR_MASK can be used as value for the error mask. - The values for the error mask are defined in linux/can/error.h . - - can_err_mask_t err_mask = ( CAN_ERR_TX_TIMEOUT | CAN_ERR_BUSOFF ); - - setsockopt(s, SOL_CAN_RAW, CAN_RAW_ERR_FILTER, - &err_mask, sizeof(err_mask)); - - 4.1.3 RAW socket option CAN_RAW_LOOPBACK - - To meet multi user needs the local loopback is enabled by default - (see chapter 3.2 for details). But in some embedded use-cases - (e.g. when only one application uses the CAN bus) this loopback - functionality can be disabled (separately for each socket): - - int loopback = 0; /* 0 = disabled, 1 = enabled (default) */ - - setsockopt(s, SOL_CAN_RAW, CAN_RAW_LOOPBACK, &loopback, sizeof(loopback)); - - 4.1.4 RAW socket option CAN_RAW_RECV_OWN_MSGS - - When the local loopback is enabled, all the sent CAN frames are - looped back to the open CAN sockets that registered for the CAN - frames' CAN-ID on this given interface to meet the multi user - needs. The reception of the CAN frames on the same socket that was - sending the CAN frame is assumed to be unwanted and therefore - disabled by default. This default behaviour may be changed on - demand: - - int recv_own_msgs = 1; /* 0 = disabled (default), 1 = enabled */ - - setsockopt(s, SOL_CAN_RAW, CAN_RAW_RECV_OWN_MSGS, - &recv_own_msgs, sizeof(recv_own_msgs)); - - 4.1.5 RAW socket option CAN_RAW_FD_FRAMES - - CAN FD support in CAN_RAW sockets can be enabled with a new socket option - CAN_RAW_FD_FRAMES which is off by default. When the new socket option is - not supported by the CAN_RAW socket (e.g. on older kernels), switching the - CAN_RAW_FD_FRAMES option returns the error -ENOPROTOOPT. - - Once CAN_RAW_FD_FRAMES is enabled the application can send both CAN frames - and CAN FD frames. OTOH the application has to handle CAN and CAN FD frames - when reading from the socket. - - CAN_RAW_FD_FRAMES enabled: CAN_MTU and CANFD_MTU are allowed - CAN_RAW_FD_FRAMES disabled: only CAN_MTU is allowed (default) - - Example: - [ remember: CANFD_MTU == sizeof(struct canfd_frame) ] - - struct canfd_frame cfd; - - nbytes = read(s, &cfd, CANFD_MTU); - - if (nbytes == CANFD_MTU) { - printf("got CAN FD frame with length %d\n", cfd.len); - /* cfd.flags contains valid data */ - } else if (nbytes == CAN_MTU) { - printf("got legacy CAN frame with length %d\n", cfd.len); - /* cfd.flags is undefined */ - } else { - fprintf(stderr, "read: invalid CAN(FD) frame\n"); - return 1; - } - - /* the content can be handled independently from the received MTU size */ - - printf("can_id: %X data length: %d data: ", cfd.can_id, cfd.len); - for (i = 0; i < cfd.len; i++) - printf("%02X ", cfd.data[i]); - - When reading with size CANFD_MTU only returns CAN_MTU bytes that have - been received from the socket a legacy CAN frame has been read into the - provided CAN FD structure. Note that the canfd_frame.flags data field is - not specified in the struct can_frame and therefore it is only valid in - CANFD_MTU sized CAN FD frames. - - Implementation hint for new CAN applications: - - To build a CAN FD aware application use struct canfd_frame as basic CAN - data structure for CAN_RAW based applications. When the application is - executed on an older Linux kernel and switching the CAN_RAW_FD_FRAMES - socket option returns an error: No problem. You'll get legacy CAN frames - or CAN FD frames and can process them the same way. - - When sending to CAN devices make sure that the device is capable to handle - CAN FD frames by checking if the device maximum transfer unit is CANFD_MTU. - The CAN device MTU can be retrieved e.g. with a SIOCGIFMTU ioctl() syscall. - - 4.1.6 RAW socket option CAN_RAW_JOIN_FILTERS - - The CAN_RAW socket can set multiple CAN identifier specific filters that - lead to multiple filters in the af_can.c filter processing. These filters - are indenpendent from each other which leads to logical OR'ed filters when - applied (see 4.1.1). - - This socket option joines the given CAN filters in the way that only CAN - frames are passed to user space that matched *all* given CAN filters. The - semantic for the applied filters is therefore changed to a logical AND. - - This is useful especially when the filterset is a combination of filters - where the CAN_INV_FILTER flag is set in order to notch single CAN IDs or - CAN ID ranges from the incoming traffic. - - 4.1.7 RAW socket returned message flags - - When using recvmsg() call, the msg->msg_flags may contain following flags: - - MSG_DONTROUTE: set when the received frame was created on the local host. - - MSG_CONFIRM: set when the frame was sent via the socket it is received on. - This flag can be interpreted as a 'transmission confirmation' when the - CAN driver supports the echo of frames on driver level, see 3.2 and 6.2. - In order to receive such messages, CAN_RAW_RECV_OWN_MSGS must be set. - - 4.2 Broadcast Manager protocol sockets (SOCK_DGRAM) - - The Broadcast Manager protocol provides a command based configuration - interface to filter and send (e.g. cyclic) CAN messages in kernel space. - - Receive filters can be used to down sample frequent messages; detect events - such as message contents changes, packet length changes, and do time-out - monitoring of received messages. - - Periodic transmission tasks of CAN frames or a sequence of CAN frames can be - created and modified at runtime; both the message content and the two - possible transmit intervals can be altered. - - A BCM socket is not intended for sending individual CAN frames using the - struct can_frame as known from the CAN_RAW socket. Instead a special BCM - configuration message is defined. The basic BCM configuration message used - to communicate with the broadcast manager and the available operations are - defined in the linux/can/bcm.h include. The BCM message consists of a - message header with a command ('opcode') followed by zero or more CAN frames. - The broadcast manager sends responses to user space in the same form: - - struct bcm_msg_head { - __u32 opcode; /* command */ - __u32 flags; /* special flags */ - __u32 count; /* run 'count' times with ival1 */ - struct timeval ival1, ival2; /* count and subsequent interval */ - canid_t can_id; /* unique can_id for task */ - __u32 nframes; /* number of can_frames following */ - struct can_frame frames[0]; - }; - - The aligned payload 'frames' uses the same basic CAN frame structure defined - at the beginning of section 4 and in the include/linux/can.h include. All - messages to the broadcast manager from user space have this structure. - - Note a CAN_BCM socket must be connected instead of bound after socket - creation (example without error checking): - - int s; - struct sockaddr_can addr; - struct ifreq ifr; - - s = socket(PF_CAN, SOCK_DGRAM, CAN_BCM); - - strcpy(ifr.ifr_name, "can0"); - ioctl(s, SIOCGIFINDEX, &ifr); - - addr.can_family = AF_CAN; - addr.can_ifindex = ifr.ifr_ifindex; - - connect(s, (struct sockaddr *)&addr, sizeof(addr)); - - (..) - - The broadcast manager socket is able to handle any number of in flight - transmissions or receive filters concurrently. The different RX/TX jobs are - distinguished by the unique can_id in each BCM message. However additional - CAN_BCM sockets are recommended to communicate on multiple CAN interfaces. - When the broadcast manager socket is bound to 'any' CAN interface (=> the - interface index is set to zero) the configured receive filters apply to any - CAN interface unless the sendto() syscall is used to overrule the 'any' CAN - interface index. When using recvfrom() instead of read() to retrieve BCM - socket messages the originating CAN interface is provided in can_ifindex. - - 4.2.1 Broadcast Manager operations - - The opcode defines the operation for the broadcast manager to carry out, - or details the broadcast managers response to several events, including - user requests. - - Transmit Operations (user space to broadcast manager): - - TX_SETUP: Create (cyclic) transmission task. - - TX_DELETE: Remove (cyclic) transmission task, requires only can_id. - - TX_READ: Read properties of (cyclic) transmission task for can_id. - - TX_SEND: Send one CAN frame. - - Transmit Responses (broadcast manager to user space): - - TX_STATUS: Reply to TX_READ request (transmission task configuration). - - TX_EXPIRED: Notification when counter finishes sending at initial interval - 'ival1'. Requires the TX_COUNTEVT flag to be set at TX_SETUP. - - Receive Operations (user space to broadcast manager): - - RX_SETUP: Create RX content filter subscription. - - RX_DELETE: Remove RX content filter subscription, requires only can_id. - - RX_READ: Read properties of RX content filter subscription for can_id. - - Receive Responses (broadcast manager to user space): - - RX_STATUS: Reply to RX_READ request (filter task configuration). - - RX_TIMEOUT: Cyclic message is detected to be absent (timer ival1 expired). - - RX_CHANGED: BCM message with updated CAN frame (detected content change). - Sent on first message received or on receipt of revised CAN messages. - - 4.2.2 Broadcast Manager message flags - - When sending a message to the broadcast manager the 'flags' element may - contain the following flag definitions which influence the behaviour: - - SETTIMER: Set the values of ival1, ival2 and count - - STARTTIMER: Start the timer with the actual values of ival1, ival2 - and count. Starting the timer leads simultaneously to emit a CAN frame. - - TX_COUNTEVT: Create the message TX_EXPIRED when count expires - - TX_ANNOUNCE: A change of data by the process is emitted immediately. - - TX_CP_CAN_ID: Copies the can_id from the message header to each - subsequent frame in frames. This is intended as usage simplification. For - TX tasks the unique can_id from the message header may differ from the - can_id(s) stored for transmission in the subsequent struct can_frame(s). - - RX_FILTER_ID: Filter by can_id alone, no frames required (nframes=0). - - RX_CHECK_DLC: A change of the DLC leads to an RX_CHANGED. - - RX_NO_AUTOTIMER: Prevent automatically starting the timeout monitor. - - RX_ANNOUNCE_RESUME: If passed at RX_SETUP and a receive timeout occurred, a - RX_CHANGED message will be generated when the (cyclic) receive restarts. - - TX_RESET_MULTI_IDX: Reset the index for the multiple frame transmission. - - RX_RTR_FRAME: Send reply for RTR-request (placed in op->frames[0]). - - 4.2.3 Broadcast Manager transmission timers - - Periodic transmission configurations may use up to two interval timers. - In this case the BCM sends a number of messages ('count') at an interval - 'ival1', then continuing to send at another given interval 'ival2'. When - only one timer is needed 'count' is set to zero and only 'ival2' is used. - When SET_TIMER and START_TIMER flag were set the timers are activated. - The timer values can be altered at runtime when only SET_TIMER is set. - - 4.2.4 Broadcast Manager message sequence transmission - - Up to 256 CAN frames can be transmitted in a sequence in the case of a cyclic - TX task configuration. The number of CAN frames is provided in the 'nframes' - element of the BCM message head. The defined number of CAN frames are added - as array to the TX_SETUP BCM configuration message. - - /* create a struct to set up a sequence of four CAN frames */ - struct { - struct bcm_msg_head msg_head; - struct can_frame frame[4]; - } mytxmsg; - - (..) - mytxmsg.msg_head.nframes = 4; - (..) - - write(s, &mytxmsg, sizeof(mytxmsg)); - - With every transmission the index in the array of CAN frames is increased - and set to zero at index overflow. - - 4.2.5 Broadcast Manager receive filter timers - - The timer values ival1 or ival2 may be set to non-zero values at RX_SETUP. - When the SET_TIMER flag is set the timers are enabled: - - ival1: Send RX_TIMEOUT when a received message is not received again within - the given time. When START_TIMER is set at RX_SETUP the timeout detection - is activated directly - even without a former CAN frame reception. - - ival2: Throttle the received message rate down to the value of ival2. This - is useful to reduce messages for the application when the signal inside the - CAN frame is stateless as state changes within the ival2 periode may get - lost. - - 4.2.6 Broadcast Manager multiplex message receive filter - - To filter for content changes in multiplex message sequences an array of more - than one CAN frames can be passed in a RX_SETUP configuration message. The - data bytes of the first CAN frame contain the mask of relevant bits that - have to match in the subsequent CAN frames with the received CAN frame. - If one of the subsequent CAN frames is matching the bits in that frame data - mark the relevant content to be compared with the previous received content. - Up to 257 CAN frames (multiplex filter bit mask CAN frame plus 256 CAN - filters) can be added as array to the TX_SETUP BCM configuration message. - - /* usually used to clear CAN frame data[] - beware of endian problems! */ - #define U64_DATA(p) (*(unsigned long long*)(p)->data) - - struct { - struct bcm_msg_head msg_head; - struct can_frame frame[5]; - } msg; - - msg.msg_head.opcode = RX_SETUP; - msg.msg_head.can_id = 0x42; - msg.msg_head.flags = 0; - msg.msg_head.nframes = 5; - U64_DATA(&msg.frame[0]) = 0xFF00000000000000ULL; /* MUX mask */ - U64_DATA(&msg.frame[1]) = 0x01000000000000FFULL; /* data mask (MUX 0x01) */ - U64_DATA(&msg.frame[2]) = 0x0200FFFF000000FFULL; /* data mask (MUX 0x02) */ - U64_DATA(&msg.frame[3]) = 0x330000FFFFFF0003ULL; /* data mask (MUX 0x33) */ - U64_DATA(&msg.frame[4]) = 0x4F07FC0FF0000000ULL; /* data mask (MUX 0x4F) */ - - write(s, &msg, sizeof(msg)); - - 4.2.7 Broadcast Manager CAN FD support - - The programming API of the CAN_BCM depends on struct can_frame which is - given as array directly behind the bcm_msg_head structure. To follow this - schema for the CAN FD frames a new flag 'CAN_FD_FRAME' in the bcm_msg_head - flags indicates that the concatenated CAN frame structures behind the - bcm_msg_head are defined as struct canfd_frame. - - struct { - struct bcm_msg_head msg_head; - struct canfd_frame frame[5]; - } msg; - - msg.msg_head.opcode = RX_SETUP; - msg.msg_head.can_id = 0x42; - msg.msg_head.flags = CAN_FD_FRAME; - msg.msg_head.nframes = 5; - (..) - - When using CAN FD frames for multiplex filtering the MUX mask is still - expected in the first 64 bit of the struct canfd_frame data section. - - 4.3 connected transport protocols (SOCK_SEQPACKET) - 4.4 unconnected transport protocols (SOCK_DGRAM) - - -5. SocketCAN core module -------------------------- - - The SocketCAN core module implements the protocol family - PF_CAN. CAN protocol modules are loaded by the core module at - runtime. The core module provides an interface for CAN protocol - modules to subscribe needed CAN IDs (see chapter 3.1). - - 5.1 can.ko module params - - - stats_timer: To calculate the SocketCAN core statistics - (e.g. current/maximum frames per second) this 1 second timer is - invoked at can.ko module start time by default. This timer can be - disabled by using stattimer=0 on the module commandline. - - - debug: (removed since SocketCAN SVN r546) - - 5.2 procfs content - - As described in chapter 3.1 the SocketCAN core uses several filter - lists to deliver received CAN frames to CAN protocol modules. These - receive lists, their filters and the count of filter matches can be - checked in the appropriate receive list. All entries contain the - device and a protocol module identifier: - - foo@bar:~$ cat /proc/net/can/rcvlist_all - - receive list 'rx_all': - (vcan3: no entry) - (vcan2: no entry) - (vcan1: no entry) - device can_id can_mask function userdata matches ident - vcan0 000 00000000 f88e6370 f6c6f400 0 raw - (any: no entry) - - In this example an application requests any CAN traffic from vcan0. - - rcvlist_all - list for unfiltered entries (no filter operations) - rcvlist_eff - list for single extended frame (EFF) entries - rcvlist_err - list for error message frames masks - rcvlist_fil - list for mask/value filters - rcvlist_inv - list for mask/value filters (inverse semantic) - rcvlist_sff - list for single standard frame (SFF) entries - - Additional procfs files in /proc/net/can - - stats - SocketCAN core statistics (rx/tx frames, match ratios, ...) - reset_stats - manual statistic reset - version - prints the SocketCAN core version and the ABI version - - 5.3 writing own CAN protocol modules - - To implement a new protocol in the protocol family PF_CAN a new - protocol has to be defined in include/linux/can.h . - The prototypes and definitions to use the SocketCAN core can be - accessed by including include/linux/can/core.h . - In addition to functions that register the CAN protocol and the - CAN device notifier chain there are functions to subscribe CAN - frames received by CAN interfaces and to send CAN frames: - - can_rx_register - subscribe CAN frames from a specific interface - can_rx_unregister - unsubscribe CAN frames from a specific interface - can_send - transmit a CAN frame (optional with local loopback) - - For details see the kerneldoc documentation in net/can/af_can.c or - the source code of net/can/raw.c or net/can/bcm.c . - -6. CAN network drivers ----------------------- - - Writing a CAN network device driver is much easier than writing a - CAN character device driver. Similar to other known network device - drivers you mainly have to deal with: - - - TX: Put the CAN frame from the socket buffer to the CAN controller. - - RX: Put the CAN frame from the CAN controller to the socket buffer. - - See e.g. at Documentation/networking/netdevices.txt . The differences - for writing CAN network device driver are described below: - - 6.1 general settings - - dev->type = ARPHRD_CAN; /* the netdevice hardware type */ - dev->flags = IFF_NOARP; /* CAN has no arp */ - - dev->mtu = CAN_MTU; /* sizeof(struct can_frame) -> legacy CAN interface */ - - or alternative, when the controller supports CAN with flexible data rate: - dev->mtu = CANFD_MTU; /* sizeof(struct canfd_frame) -> CAN FD interface */ - - The struct can_frame or struct canfd_frame is the payload of each socket - buffer (skbuff) in the protocol family PF_CAN. - - 6.2 local loopback of sent frames - - As described in chapter 3.2 the CAN network device driver should - support a local loopback functionality similar to the local echo - e.g. of tty devices. In this case the driver flag IFF_ECHO has to be - set to prevent the PF_CAN core from locally echoing sent frames - (aka loopback) as fallback solution: - - dev->flags = (IFF_NOARP | IFF_ECHO); - - 6.3 CAN controller hardware filters - - To reduce the interrupt load on deep embedded systems some CAN - controllers support the filtering of CAN IDs or ranges of CAN IDs. - These hardware filter capabilities vary from controller to - controller and have to be identified as not feasible in a multi-user - networking approach. The use of the very controller specific - hardware filters could make sense in a very dedicated use-case, as a - filter on driver level would affect all users in the multi-user - system. The high efficient filter sets inside the PF_CAN core allow - to set different multiple filters for each socket separately. - Therefore the use of hardware filters goes to the category 'handmade - tuning on deep embedded systems'. The author is running a MPC603e - @133MHz with four SJA1000 CAN controllers from 2002 under heavy bus - load without any problems ... - - 6.4 The virtual CAN driver (vcan) - - Similar to the network loopback devices, vcan offers a virtual local - CAN interface. A full qualified address on CAN consists of - - - a unique CAN Identifier (CAN ID) - - the CAN bus this CAN ID is transmitted on (e.g. can0) - - so in common use cases more than one virtual CAN interface is needed. - - The virtual CAN interfaces allow the transmission and reception of CAN - frames without real CAN controller hardware. Virtual CAN network - devices are usually named 'vcanX', like vcan0 vcan1 vcan2 ... - When compiled as a module the virtual CAN driver module is called vcan.ko - - Since Linux Kernel version 2.6.24 the vcan driver supports the Kernel - netlink interface to create vcan network devices. The creation and - removal of vcan network devices can be managed with the ip(8) tool: - - - Create a virtual CAN network interface: - $ ip link add type vcan - - - Create a virtual CAN network interface with a specific name 'vcan42': - $ ip link add dev vcan42 type vcan - - - Remove a (virtual CAN) network interface 'vcan42': - $ ip link del vcan42 - - 6.5 The CAN network device driver interface - - The CAN network device driver interface provides a generic interface - to setup, configure and monitor CAN network devices. The user can then - configure the CAN device, like setting the bit-timing parameters, via - the netlink interface using the program "ip" from the "IPROUTE2" - utility suite. The following chapter describes briefly how to use it. - Furthermore, the interface uses a common data structure and exports a - set of common functions, which all real CAN network device drivers - should use. Please have a look to the SJA1000 or MSCAN driver to - understand how to use them. The name of the module is can-dev.ko. - - 6.5.1 Netlink interface to set/get devices properties - - The CAN device must be configured via netlink interface. The supported - netlink message types are defined and briefly described in - "include/linux/can/netlink.h". CAN link support for the program "ip" - of the IPROUTE2 utility suite is available and it can be used as shown - below: - - - Setting CAN device properties: - - $ ip link set can0 type can help - Usage: ip link set DEVICE type can - [ bitrate BITRATE [ sample-point SAMPLE-POINT] ] | - [ tq TQ prop-seg PROP_SEG phase-seg1 PHASE-SEG1 - phase-seg2 PHASE-SEG2 [ sjw SJW ] ] - - [ dbitrate BITRATE [ dsample-point SAMPLE-POINT] ] | - [ dtq TQ dprop-seg PROP_SEG dphase-seg1 PHASE-SEG1 - dphase-seg2 PHASE-SEG2 [ dsjw SJW ] ] - - [ loopback { on | off } ] - [ listen-only { on | off } ] - [ triple-sampling { on | off } ] - [ one-shot { on | off } ] - [ berr-reporting { on | off } ] - [ fd { on | off } ] - [ fd-non-iso { on | off } ] - [ presume-ack { on | off } ] - - [ restart-ms TIME-MS ] - [ restart ] - - Where: BITRATE := { 1..1000000 } - SAMPLE-POINT := { 0.000..0.999 } - TQ := { NUMBER } - PROP-SEG := { 1..8 } - PHASE-SEG1 := { 1..8 } - PHASE-SEG2 := { 1..8 } - SJW := { 1..4 } - RESTART-MS := { 0 | NUMBER } - - - Display CAN device details and statistics: - - $ ip -details -statistics link show can0 - 2: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UP qlen 10 - link/can - can <TRIPLE-SAMPLING> state ERROR-ACTIVE restart-ms 100 - bitrate 125000 sample_point 0.875 - tq 125 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1 - sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1 - clock 8000000 - re-started bus-errors arbit-lost error-warn error-pass bus-off - 41 17457 0 41 42 41 - RX: bytes packets errors dropped overrun mcast - 140859 17608 17457 0 0 0 - TX: bytes packets errors dropped carrier collsns - 861 112 0 41 0 0 - - More info to the above output: - - "<TRIPLE-SAMPLING>" - Shows the list of selected CAN controller modes: LOOPBACK, - LISTEN-ONLY, or TRIPLE-SAMPLING. - - "state ERROR-ACTIVE" - The current state of the CAN controller: "ERROR-ACTIVE", - "ERROR-WARNING", "ERROR-PASSIVE", "BUS-OFF" or "STOPPED" - - "restart-ms 100" - Automatic restart delay time. If set to a non-zero value, a - restart of the CAN controller will be triggered automatically - in case of a bus-off condition after the specified delay time - in milliseconds. By default it's off. - - "bitrate 125000 sample-point 0.875" - Shows the real bit-rate in bits/sec and the sample-point in the - range 0.000..0.999. If the calculation of bit-timing parameters - is enabled in the kernel (CONFIG_CAN_CALC_BITTIMING=y), the - bit-timing can be defined by setting the "bitrate" argument. - Optionally the "sample-point" can be specified. By default it's - 0.000 assuming CIA-recommended sample-points. - - "tq 125 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1" - Shows the time quanta in ns, propagation segment, phase buffer - segment 1 and 2 and the synchronisation jump width in units of - tq. They allow to define the CAN bit-timing in a hardware - independent format as proposed by the Bosch CAN 2.0 spec (see - chapter 8 of http://www.semiconductors.bosch.de/pdf/can2spec.pdf). - - "sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1 - clock 8000000" - Shows the bit-timing constants of the CAN controller, here the - "sja1000". The minimum and maximum values of the time segment 1 - and 2, the synchronisation jump width in units of tq, the - bitrate pre-scaler and the CAN system clock frequency in Hz. - These constants could be used for user-defined (non-standard) - bit-timing calculation algorithms in user-space. - - "re-started bus-errors arbit-lost error-warn error-pass bus-off" - Shows the number of restarts, bus and arbitration lost errors, - and the state changes to the error-warning, error-passive and - bus-off state. RX overrun errors are listed in the "overrun" - field of the standard network statistics. - - 6.5.2 Setting the CAN bit-timing - - The CAN bit-timing parameters can always be defined in a hardware - independent format as proposed in the Bosch CAN 2.0 specification - specifying the arguments "tq", "prop_seg", "phase_seg1", "phase_seg2" - and "sjw": - - $ ip link set canX type can tq 125 prop-seg 6 \ - phase-seg1 7 phase-seg2 2 sjw 1 - - If the kernel option CONFIG_CAN_CALC_BITTIMING is enabled, CIA - recommended CAN bit-timing parameters will be calculated if the bit- - rate is specified with the argument "bitrate": - - $ ip link set canX type can bitrate 125000 - - Note that this works fine for the most common CAN controllers with - standard bit-rates but may *fail* for exotic bit-rates or CAN system - clock frequencies. Disabling CONFIG_CAN_CALC_BITTIMING saves some - space and allows user-space tools to solely determine and set the - bit-timing parameters. The CAN controller specific bit-timing - constants can be used for that purpose. They are listed by the - following command: - - $ ip -details link show can0 - ... - sja1000: clock 8000000 tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1 - - 6.5.3 Starting and stopping the CAN network device - - A CAN network device is started or stopped as usual with the command - "ifconfig canX up/down" or "ip link set canX up/down". Be aware that - you *must* define proper bit-timing parameters for real CAN devices - before you can start it to avoid error-prone default settings: - - $ ip link set canX up type can bitrate 125000 - - A device may enter the "bus-off" state if too many errors occurred on - the CAN bus. Then no more messages are received or sent. An automatic - bus-off recovery can be enabled by setting the "restart-ms" to a - non-zero value, e.g.: - - $ ip link set canX type can restart-ms 100 - - Alternatively, the application may realize the "bus-off" condition - by monitoring CAN error message frames and do a restart when - appropriate with the command: - - $ ip link set canX type can restart - - Note that a restart will also create a CAN error message frame (see - also chapter 3.3). - - 6.6 CAN FD (flexible data rate) driver support - - CAN FD capable CAN controllers support two different bitrates for the - arbitration phase and the payload phase of the CAN FD frame. Therefore a - second bit timing has to be specified in order to enable the CAN FD bitrate. - - Additionally CAN FD capable CAN controllers support up to 64 bytes of - payload. The representation of this length in can_frame.can_dlc and - canfd_frame.len for userspace applications and inside the Linux network - layer is a plain value from 0 .. 64 instead of the CAN 'data length code'. - The data length code was a 1:1 mapping to the payload length in the legacy - CAN frames anyway. The payload length to the bus-relevant DLC mapping is - only performed inside the CAN drivers, preferably with the helper - functions can_dlc2len() and can_len2dlc(). - - The CAN netdevice driver capabilities can be distinguished by the network - devices maximum transfer unit (MTU): - - MTU = 16 (CAN_MTU) => sizeof(struct can_frame) => 'legacy' CAN device - MTU = 72 (CANFD_MTU) => sizeof(struct canfd_frame) => CAN FD capable device - - The CAN device MTU can be retrieved e.g. with a SIOCGIFMTU ioctl() syscall. - N.B. CAN FD capable devices can also handle and send legacy CAN frames. - - When configuring CAN FD capable CAN controllers an additional 'data' bitrate - has to be set. This bitrate for the data phase of the CAN FD frame has to be - at least the bitrate which was configured for the arbitration phase. This - second bitrate is specified analogue to the first bitrate but the bitrate - setting keywords for the 'data' bitrate start with 'd' e.g. dbitrate, - dsample-point, dsjw or dtq and similar settings. When a data bitrate is set - within the configuration process the controller option "fd on" can be - specified to enable the CAN FD mode in the CAN controller. This controller - option also switches the device MTU to 72 (CANFD_MTU). - - The first CAN FD specification presented as whitepaper at the International - CAN Conference 2012 needed to be improved for data integrity reasons. - Therefore two CAN FD implementations have to be distinguished today: - - - ISO compliant: The ISO 11898-1:2015 CAN FD implementation (default) - - non-ISO compliant: The CAN FD implementation following the 2012 whitepaper - - Finally there are three types of CAN FD controllers: - - 1. ISO compliant (fixed) - 2. non-ISO compliant (fixed, like the M_CAN IP core v3.0.1 in m_can.c) - 3. ISO/non-ISO CAN FD controllers (switchable, like the PEAK PCAN-USB FD) - - The current ISO/non-ISO mode is announced by the CAN controller driver via - netlink and displayed by the 'ip' tool (controller option FD-NON-ISO). - The ISO/non-ISO-mode can be altered by setting 'fd-non-iso {on|off}' for - switchable CAN FD controllers only. - - Example configuring 500 kbit/s arbitration bitrate and 4 Mbit/s data bitrate: - - $ ip link set can0 up type can bitrate 500000 sample-point 0.75 \ - dbitrate 4000000 dsample-point 0.8 fd on - $ ip -details link show can0 - 5: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 72 qdisc pfifo_fast state UNKNOWN \ - mode DEFAULT group default qlen 10 - link/can promiscuity 0 - can <FD> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 - bitrate 500000 sample-point 0.750 - tq 50 prop-seg 14 phase-seg1 15 phase-seg2 10 sjw 1 - pcan_usb_pro_fd: tseg1 1..64 tseg2 1..16 sjw 1..16 brp 1..1024 \ - brp-inc 1 - dbitrate 4000000 dsample-point 0.800 - dtq 12 dprop-seg 7 dphase-seg1 8 dphase-seg2 4 dsjw 1 - pcan_usb_pro_fd: dtseg1 1..16 dtseg2 1..8 dsjw 1..4 dbrp 1..1024 \ - dbrp-inc 1 - clock 80000000 - - Example when 'fd-non-iso on' is added on this switchable CAN FD adapter: - can <FD,FD-NON-ISO> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 - - 6.7 Supported CAN hardware - - Please check the "Kconfig" file in "drivers/net/can" to get an actual - list of the support CAN hardware. On the SocketCAN project website - (see chapter 7) there might be further drivers available, also for - older kernel versions. - -7. SocketCAN resources ------------------------ - - The Linux CAN / SocketCAN project resources (project site / mailing list) - are referenced in the MAINTAINERS file in the Linux source tree. - Search for CAN NETWORK [LAYERS|DRIVERS]. - -8. Credits ----------- - - Oliver Hartkopp (PF_CAN core, filters, drivers, bcm, SJA1000 driver) - Urs Thuermann (PF_CAN core, kernel integration, socket interfaces, raw, vcan) - Jan Kizka (RT-SocketCAN core, Socket-API reconciliation) - Wolfgang Grandegger (RT-SocketCAN core & drivers, Raw Socket-API reviews, - CAN device driver interface, MSCAN driver) - Robert Schwebel (design reviews, PTXdist integration) - Marc Kleine-Budde (design reviews, Kernel 2.6 cleanups, drivers) - Benedikt Spranger (reviews) - Thomas Gleixner (LKML reviews, coding style, posting hints) - Andrey Volkov (kernel subtree structure, ioctls, MSCAN driver) - Matthias Brukner (first SJA1000 CAN netdevice implementation Q2/2003) - Klaus Hitschler (PEAK driver integration) - Uwe Koppe (CAN netdevices with PF_PACKET approach) - Michael Schulze (driver layer loopback requirement, RT CAN drivers review) - Pavel Pisa (Bit-timing calculation) - Sascha Hauer (SJA1000 platform driver) - Sebastian Haas (SJA1000 EMS PCI driver) - Markus Plessing (SJA1000 EMS PCI driver) - Per Dalen (SJA1000 Kvaser PCI driver) - Sam Ravnborg (reviews, coding style, kbuild help) diff --git a/Documentation/networking/dsa/dsa.txt b/Documentation/networking/dsa/dsa.txt index b8b40753133e..25170ad7d25b 100644 --- a/Documentation/networking/dsa/dsa.txt +++ b/Documentation/networking/dsa/dsa.txt @@ -385,11 +385,6 @@ Switch configuration avoid relying on what a previous software agent such as a bootloader/firmware may have previously configured. -- set_addr: Some switches require the programming of the management interface's - Ethernet MAC address, switch drivers can also disable ageing of MAC addresses - on the management interface and "hardcode"/"force" this MAC address for the - CPU/management interface as an optimization - PHY devices and link management ------------------------------- diff --git a/Documentation/networking/filter.txt b/Documentation/networking/filter.txt index 87814859cfc2..a4508ec1816b 100644 --- a/Documentation/networking/filter.txt +++ b/Documentation/networking/filter.txt @@ -1134,7 +1134,7 @@ The verifier's knowledge about the variable offset consists of: mask and value; no bit should ever be 1 in both. For example, if a byte is read into a register from memory, the register's top 56 bits are known zero, while the low 8 are unknown - which is represented as the tnum (0x0; 0xff). If we -then OR this with 0x40, we get (0x40; 0xcf), then if we add 1 we get (0x0; +then OR this with 0x40, we get (0x40; 0xbf), then if we add 1 we get (0x0; 0x1ff), because of potential carries. Besides arithmetic, the register state can also be updated by conditional branches. For instance, if a SCALAR_VALUE is compared > 8, in the 'true' branch diff --git a/Documentation/networking/ieee802154.txt b/Documentation/networking/ieee802154.txt index 057e9fdbfac9..e74d8e1da0e2 100644 --- a/Documentation/networking/ieee802154.txt +++ b/Documentation/networking/ieee802154.txt @@ -97,6 +97,46 @@ The include/net/mac802154.h defines following functions: - void ieee802154_unregister_hw(struct ieee802154_hw *hw): freeing registered PHY + - void ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, + u8 lqi): + telling 802.15.4 module there is a new received frame in the skb with + the RF Link Quality Indicator (LQI) from the hardware device + + - void ieee802154_xmit_complete(struct ieee802154_hw *hw, struct sk_buff *skb, + bool ifs_handling): + telling 802.15.4 module the frame in the skb is or going to be + transmitted through the hardware device + +The device driver must implement the following callbacks in the IEEE 802.15.4 +operations structure at least: +struct ieee802154_ops { + ... + int (*start)(struct ieee802154_hw *hw); + void (*stop)(struct ieee802154_hw *hw); + ... + int (*xmit_async)(struct ieee802154_hw *hw, struct sk_buff *skb); + int (*ed)(struct ieee802154_hw *hw, u8 *level); + int (*set_channel)(struct ieee802154_hw *hw, u8 page, u8 channel); + ... +}; + + - int start(struct ieee802154_hw *hw): + handler that 802.15.4 module calls for the hardware device initialization. + + - void stop(struct ieee802154_hw *hw): + handler that 802.15.4 module calls for the hardware device cleanup. + + - int xmit_async(struct ieee802154_hw *hw, struct sk_buff *skb): + handler that 802.15.4 module calls for each frame in the skb going to be + transmitted through the hardware device. + + - int ed(struct ieee802154_hw *hw, u8 *level): + handler that 802.15.4 module calls for Energy Detection from the hardware + device. + + - int set_channel(struct ieee802154_hw *hw, u8 page, u8 channel): + set radio for listening on specific channel of the hardware device. + Moreover IEEE 802.15.4 device operations structure should be filled. Fake drivers diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst index 7d4b15977d61..90966c2692d8 100644 --- a/Documentation/networking/index.rst +++ b/Documentation/networking/index.rst @@ -7,6 +7,7 @@ Contents: :maxdepth: 2 batman-adv + can kapi z8530book msg_zerocopy diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 46c7e1085efc..3f2c40d8e6aa 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -606,6 +606,7 @@ tcp_fastopen_blackhole_timeout_sec - INTEGER This time period will grow exponentially when more blackhole issues get detected right after Fastopen is re-enabled and will reset to initial value when the blackhole issue goes away. + 0 to disable the blackhole detection. By default, it is set to 1hr. tcp_syn_retries - INTEGER diff --git a/Documentation/networking/kapi.rst b/Documentation/networking/kapi.rst index 580289f345da..f03ae64be8bc 100644 --- a/Documentation/networking/kapi.rst +++ b/Documentation/networking/kapi.rst @@ -145,3 +145,27 @@ PHY Support .. kernel-doc:: drivers/net/phy/mdio_bus.c :internal: + +PHYLINK +------- + + PHYLINK interfaces traditional network drivers with PHYLIB, fixed-links, + and SFF modules (eg, hot-pluggable SFP) that may contain PHYs. PHYLINK + provides management of the link state and link modes. + +.. kernel-doc:: include/linux/phylink.h + :internal: + +.. kernel-doc:: drivers/net/phy/phylink.c + +SFP support +----------- + +.. kernel-doc:: drivers/net/phy/sfp-bus.c + :internal: + +.. kernel-doc:: include/linux/sfp.h + :internal: + +.. kernel-doc:: drivers/net/phy/sfp-bus.c + :export: diff --git a/Documentation/networking/netdev-features.txt b/Documentation/networking/netdev-features.txt index 7413eb05223b..c77f9d57eb91 100644 --- a/Documentation/networking/netdev-features.txt +++ b/Documentation/networking/netdev-features.txt @@ -163,3 +163,12 @@ This requests that the NIC receive all possible frames, including errored frames (such as bad FCS, etc). This can be helpful when sniffing a link with bad packets on it. Some NICs may receive more packets if also put into normal PROMISC mode. + +* rx-gro-hw + +This requests that the NIC enables Hardware GRO (generic receive offload). +Hardware GRO is basically the exact reverse of TSO, and is generally +stricter than Hardware LRO. A packet stream merged by Hardware GRO must +be re-segmentable by GSO or TSO back to the exact original packet stream. +Hardware GRO is dependent on RXCSUM since every packet successfully merged +by hardware must also have the checksum verified by hardware. diff --git a/Documentation/networking/pktgen.txt b/Documentation/networking/pktgen.txt index 2c4e3354e128..d2fd78f85aa4 100644 --- a/Documentation/networking/pktgen.txt +++ b/Documentation/networking/pktgen.txt @@ -12,8 +12,8 @@ suitable sample script and configure that. On a dual CPU: ps aux | grep pkt -root 129 0.3 0.0 0 0 ? SW 2003 523:20 [pktgen/0] -root 130 0.3 0.0 0 0 ? SW 2003 509:50 [pktgen/1] +root 129 0.3 0.0 0 0 ? SW 2003 523:20 [kpktgend_0] +root 130 0.3 0.0 0 0 ? SW 2003 509:50 [kpktgend_1] For monitoring and control pktgen creates: @@ -113,9 +113,16 @@ Configuring devices =================== This is done via the /proc interface, and most easily done via pgset as defined in the sample scripts. +You need to specify PGDEV environment variable to use functions from sample +scripts, i.e.: +export PGDEV=/proc/net/pktgen/eth4@0 +source samples/pktgen/functions.sh Examples: + pg_ctrl start starts injection. + pg_ctrl stop aborts injection. Also, ^C aborts generator. + pgset "clone_skb 1" sets the number of copies of the same packet pgset "clone_skb 0" use single SKB for all transmits pgset "burst 8" uses xmit_more API to queue 8 copies of the same @@ -165,8 +172,12 @@ Examples: IPSEC # IPsec encapsulation (needs CONFIG_XFRM) NODE_ALLOC # node specific memory allocation NO_TIMESTAMP # disable timestamping + pgset 'flag ![name]' Clear a flag to determine behaviour. + Note that you might need to use single quote in + interactive mode, so that your shell wouldn't expand + the specified flag as a history command. - pgset spi SPI_VALUE Set specific SA used to transform packet. + pgset "spi [SPI_VALUE]" Set specific SA used to transform packet. pgset "udp_src_min 9" set UDP source port min, If < udp_src_max, then cycle through the port range. @@ -207,8 +218,6 @@ Examples: pgset "tos XX" set former IPv4 TOS field (e.g. "tos 28" for AF11 no ECN, default 00) pgset "traffic_class XX" set former IPv6 TRAFFIC CLASS (e.g. "traffic_class B8" for EF no ECN, default 00) - pgset stop aborts injection. Also, ^C aborts generator. - pgset "rate 300M" set rate to 300 Mb/s pgset "ratep 1000000" set rate to 1Mpps diff --git a/Documentation/networking/xfrm_device.txt b/Documentation/networking/xfrm_device.txt new file mode 100644 index 000000000000..50c34ca65efe --- /dev/null +++ b/Documentation/networking/xfrm_device.txt @@ -0,0 +1,135 @@ + +=============================================== +XFRM device - offloading the IPsec computations +=============================================== +Shannon Nelson <shannon.nelson@oracle.com> + + +Overview +======== + +IPsec is a useful feature for securing network traffic, but the +computational cost is high: a 10Gbps link can easily be brought down +to under 1Gbps, depending on the traffic and link configuration. +Luckily, there are NICs that offer a hardware based IPsec offload which +can radically increase throughput and decrease CPU utilization. The XFRM +Device interface allows NIC drivers to offer to the stack access to the +hardware offload. + +Userland access to the offload is typically through a system such as +libreswan or KAME/raccoon, but the iproute2 'ip xfrm' command set can +be handy when experimenting. An example command might look something +like this: + + ip x s add proto esp dst 14.0.0.70 src 14.0.0.52 spi 0x07 mode transport \ + reqid 0x07 replay-window 32 \ + aead 'rfc4106(gcm(aes))' 0x44434241343332312423222114131211f4f3f2f1 128 \ + sel src 14.0.0.52/24 dst 14.0.0.70/24 proto tcp \ + offload dev eth4 dir in + +Yes, that's ugly, but that's what shell scripts and/or libreswan are for. + + + +Callbacks to implement +====================== + +/* from include/linux/netdevice.h */ +struct xfrmdev_ops { + int (*xdo_dev_state_add) (struct xfrm_state *x); + void (*xdo_dev_state_delete) (struct xfrm_state *x); + void (*xdo_dev_state_free) (struct xfrm_state *x); + bool (*xdo_dev_offload_ok) (struct sk_buff *skb, + struct xfrm_state *x); + void (*xdo_dev_state_advance_esn) (struct xfrm_state *x); +}; + +The NIC driver offering ipsec offload will need to implement these +callbacks to make the offload available to the network stack's +XFRM subsytem. Additionally, the feature bits NETIF_F_HW_ESP and +NETIF_F_HW_ESP_TX_CSUM will signal the availability of the offload. + + + +Flow +==== + +At probe time and before the call to register_netdev(), the driver should +set up local data structures and XFRM callbacks, and set the feature bits. +The XFRM code's listener will finish the setup on NETDEV_REGISTER. + + adapter->netdev->xfrmdev_ops = &ixgbe_xfrmdev_ops; + adapter->netdev->features |= NETIF_F_HW_ESP; + adapter->netdev->hw_enc_features |= NETIF_F_HW_ESP; + +When new SAs are set up with a request for "offload" feature, the +driver's xdo_dev_state_add() will be given the new SA to be offloaded +and an indication of whether it is for Rx or Tx. The driver should + - verify the algorithm is supported for offloads + - store the SA information (key, salt, target-ip, protocol, etc) + - enable the HW offload of the SA + +The driver can also set an offload_handle in the SA, an opaque void pointer +that can be used to convey context into the fast-path offload requests. + + xs->xso.offload_handle = context; + + +When the network stack is preparing an IPsec packet for an SA that has +been setup for offload, it first calls into xdo_dev_offload_ok() with +the skb and the intended offload state to ask the driver if the offload +will serviceable. This can check the packet information to be sure the +offload can be supported (e.g. IPv4 or IPv6, no IPv4 options, etc) and +return true of false to signify its support. + +When ready to send, the driver needs to inspect the Tx packet for the +offload information, including the opaque context, and set up the packet +send accordingly. + + xs = xfrm_input_state(skb); + context = xs->xso.offload_handle; + set up HW for send + +The stack has already inserted the appropriate IPsec headers in the +packet data, the offload just needs to do the encryption and fix up the +header values. + + +When a packet is received and the HW has indicated that it offloaded a +decryption, the driver needs to add a reference to the decoded SA into +the packet's skb. At this point the data should be decrypted but the +IPsec headers are still in the packet data; they are removed later up +the stack in xfrm_input(). + + find and hold the SA that was used to the Rx skb + get spi, protocol, and destination IP from packet headers + xs = find xs from (spi, protocol, dest_IP) + xfrm_state_hold(xs); + + store the state information into the skb + skb->sp = secpath_dup(skb->sp); + skb->sp->xvec[skb->sp->len++] = xs; + skb->sp->olen++; + + indicate the success and/or error status of the offload + xo = xfrm_offload(skb); + xo->flags = CRYPTO_DONE; + xo->status = crypto_status; + + hand the packet to napi_gro_receive() as usual + +In ESN mode, xdo_dev_state_advance_esn() is called from xfrm_replay_advance_esn(). +Driver will check packet seq number and update HW ESN state machine if needed. + +When the SA is removed by the user, the driver's xdo_dev_state_delete() +is asked to disable the offload. Later, xdo_dev_state_free() is called +from a garbage collection routine after all reference counts to the state +have been removed and any remaining resources can be cleared for the +offload state. How these are used by the driver will depend on specific +hardware needs. + +As a netdev is set to DOWN the XFRM stack's netdev listener will call +xdo_dev_state_delete() and xdo_dev_state_free() on any remaining offloaded +states. + + diff --git a/Documentation/networking/xfrm_proc.txt b/Documentation/networking/xfrm_proc.txt index d0d8bafa9016..2eae619ab67b 100644 --- a/Documentation/networking/xfrm_proc.txt +++ b/Documentation/networking/xfrm_proc.txt @@ -5,13 +5,15 @@ Masahide NAKAMURA <nakam@linux-ipv6.org> Transformation Statistics ------------------------- -xfrm_proc is a statistics shown factor dropped by transformation -for developer. -It is a counter designed from current transformation source code -and defined like linux private MIB. -Inbound statistics -~~~~~~~~~~~~~~~~~~ +The xfrm_proc code is a set of statistics showing numbers of packets +dropped by the transformation code and why. These counters are defined +as part of the linux private MIB. These counters can be viewed in +/proc/net/xfrm_stat. + + +Inbound errors +~~~~~~~~~~~~~~ XfrmInError: All errors which is not matched others XfrmInBufferError: @@ -46,6 +48,10 @@ XfrmInPolBlock: Policy discards XfrmInPolError: Policy error +XfrmAcquireError: + State hasn't been fully acquired before use +XfrmFwdHdrError: + Forward routing of a packet is not allowed Outbound errors ~~~~~~~~~~~~~~~ @@ -72,3 +78,5 @@ XfrmOutPolDead: Policy is dead XfrmOutPolError: Policy error +XfrmOutStateInvalid: + State is invalid, perhaps expired diff --git a/Documentation/sysctl/net.txt b/Documentation/sysctl/net.txt index b67044a2575f..35c62f522754 100644 --- a/Documentation/sysctl/net.txt +++ b/Documentation/sysctl/net.txt @@ -95,7 +95,9 @@ dev_weight -------------- The maximum number of packets that kernel can handle on a NAPI interrupt, -it's a Per-CPU variable. +it's a Per-CPU variable. For drivers that support LRO or GRO_HW, a hardware +aggregated packet is counted as one packet in this context. + Default: 64 dev_weight_rx_bias diff --git a/Documentation/w1/masters/w1-gpio b/Documentation/w1/masters/w1-gpio index af5d3b4aa851..623961d9e83f 100644 --- a/Documentation/w1/masters/w1-gpio +++ b/Documentation/w1/masters/w1-gpio @@ -8,17 +8,27 @@ Description ----------- GPIO 1-wire bus master driver. The driver uses the GPIO API to control the -wire and the GPIO pin can be specified using platform data. +wire and the GPIO pin can be specified using GPIO machine descriptor tables. +It is also possible to define the master using device tree, see +Documentation/devicetree/bindings/w1/w1-gpio.txt Example (mach-at91) ------------------- +#include <linux/gpio/machine.h> #include <linux/w1-gpio.h> +static struct gpiod_lookup_table foo_w1_gpiod_table = { + .dev_id = "w1-gpio", + .table = { + GPIO_LOOKUP_IDX("at91-gpio", AT91_PIN_PB20, NULL, 0, + GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN), + }, +}; + static struct w1_gpio_platform_data foo_w1_gpio_pdata = { - .pin = AT91_PIN_PB20, - .is_open_drain = 1, + .ext_pullup_enable_pin = -EINVAL, }; static struct platform_device foo_w1_device = { @@ -30,4 +40,5 @@ static struct platform_device foo_w1_device = { ... at91_set_GPIO_periph(foo_w1_gpio_pdata.pin, 1); at91_set_multi_drive(foo_w1_gpio_pdata.pin, 1); + gpiod_add_lookup_table(&foo_w1_gpiod_table); platform_device_register(&foo_w1_device); |