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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc and other driver updates from Greg KH:
"Here is the big set of char/misc and other driver subsystem changes
for 6.8-rc1.
Other than lots of binder driver changes (as you can see by the merge
conflicts) included in here are:
- lots of iio driver updates and additions
- spmi driver updates
- eeprom driver updates
- firmware driver updates
- ocxl driver updates
- mhi driver updates
- w1 driver updates
- nvmem driver updates
- coresight driver updates
- platform driver remove callback api changes
- tags.sh script updates
- bus_type constant marking cleanups
- lots of other small driver updates
All of these have been in linux-next for a while with no reported
issues"
* tag 'char-misc-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (341 commits)
android: removed duplicate linux/errno
uio: Fix use-after-free in uio_open
drivers: soc: xilinx: add check for platform
firmware: xilinx: Export function to use in other module
scripts/tags.sh: remove find_sources
scripts/tags.sh: use -n to test archinclude
scripts/tags.sh: add local annotation
scripts/tags.sh: use more portable -path instead of -wholename
scripts/tags.sh: Update comment (addition of gtags)
firmware: zynqmp: Convert to platform remove callback returning void
firmware: turris-mox-rwtm: Convert to platform remove callback returning void
firmware: stratix10-svc: Convert to platform remove callback returning void
firmware: stratix10-rsu: Convert to platform remove callback returning void
firmware: raspberrypi: Convert to platform remove callback returning void
firmware: qemu_fw_cfg: Convert to platform remove callback returning void
firmware: mtk-adsp-ipc: Convert to platform remove callback returning void
firmware: imx-dsp: Convert to platform remove callback returning void
firmware: coreboot_table: Convert to platform remove callback returning void
firmware: arm_scpi: Convert to platform remove callback returning void
firmware: arm_scmi: Convert to platform remove callback returning void
...
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Now that the driver core can properly handle constant struct bus_type,
move the ssam_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.
It's also never used outside of
drivers/platform/surface/aggregator/bus.c so make it static and don't
export it as no one is using it.
Cc: Maximilian Luz <luzmaximilian@gmail.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Cc: <platform-driver-x86@vger.kernel.org>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/2023121957-tapered-upswing-8326@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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crc_ccitt_false() was introduced in commit 0d85adb5fbd33 ("lib/crc-ccitt:
Add CCITT-FALSE CRC16 variant"), but it is redundant with crc_itu_t().
Since the latter is more used, it is the one being kept.
Link: https://lkml.kernel.org/r/20231219131154.748577-1-Mathis.Marion@silabs.com
Signed-off-by: Mathis Marion <mathis.marion@silabs.com>
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>
Cc: Jérôme Pouiller <jerome.pouiller@silabs.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).
As found with Coccinelle[1], add __counted_by for struct ssam_event.
[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
Cc: Maximilian Luz <luzmaximilian@gmail.com>
Cc: platform-driver-x86@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20230922175436.work.031-kees@kernel.org
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
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Make to_ssam_device_driver() a bit safer by replacing container_of()
with container_of_const() to respect the constness of the passed in
pointer, instead of silently discarding any const specifications. This
change also makes it more similar to to_ssam_device(), which already
uses container_of_const().
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20230525205041.2774947-1-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here is the large set of driver core changes for 6.3-rc1.
There's a lot of changes this development cycle, most of the work
falls into two different categories:
- fw_devlink fixes and updates. This has gone through numerous review
cycles and lots of review and testing by lots of different devices.
Hopefully all should be good now, and Saravana will be keeping a
watch for any potential regression on odd embedded systems.
- driver core changes to work to make struct bus_type able to be
moved into read-only memory (i.e. const) The recent work with Rust
has pointed out a number of areas in the driver core where we are
passing around and working with structures that really do not have
to be dynamic at all, and they should be able to be read-only
making things safer overall. This is the contuation of that work
(started last release with kobject changes) in moving struct
bus_type to be constant. We didn't quite make it for this release,
but the remaining patches will be finished up for the release after
this one, but the groundwork has been laid for this effort.
Other than that we have in here:
- debugfs memory leak fixes in some subsystems
- error path cleanups and fixes for some never-able-to-be-hit
codepaths.
- cacheinfo rework and fixes
- Other tiny fixes, full details are in the shortlog
All of these have been in linux-next for a while with no reported
problems"
[ Geert Uytterhoeven points out that that last sentence isn't true, and
that there's a pending report that has a fix that is queued up - Linus ]
* tag 'driver-core-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (124 commits)
debugfs: drop inline constant formatting for ERR_PTR(-ERROR)
OPP: fix error checking in opp_migrate_dentry()
debugfs: update comment of debugfs_rename()
i3c: fix device.h kernel-doc warnings
dma-mapping: no need to pass a bus_type into get_arch_dma_ops()
driver core: class: move EXPORT_SYMBOL_GPL() lines to the correct place
Revert "driver core: add error handling for devtmpfs_create_node()"
Revert "devtmpfs: add debug info to handle()"
Revert "devtmpfs: remove return value of devtmpfs_delete_node()"
driver core: cpu: don't hand-override the uevent bus_type callback.
devtmpfs: remove return value of devtmpfs_delete_node()
devtmpfs: add debug info to handle()
driver core: add error handling for devtmpfs_create_node()
driver core: bus: update my copyright notice
driver core: bus: add bus_get_dev_root() function
driver core: bus: constify bus_unregister()
driver core: bus: constify some internal functions
driver core: bus: constify bus_get_kset()
driver core: bus: constify bus_register/unregister_notifier()
driver core: remove private pointer from struct bus_type
...
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ambiguities
We currently have a struct ssam_request_sync and a function
ssam_request_sync(). While this is valid C, there are some downsides to
it.
One of these is that current Sphinx versions (>= 3.0) cannot
disambiguate between the two (see disucssion and pull request linked
below). It instead emits a "WARNING: Duplicate C declaration" and links
for the struct and function in the resulting documentation link to the
same entry (i.e. both to either function or struct documentation)
instead of their respective own entries.
While we could just ignore that and wait for a fix, there's also a point
to be made that the current naming can be somewhat confusing when
searching (e.g. via grep) or trying to understand the levels of
abstraction at play:
We currently have struct ssam_request_sync and associated functions
ssam_request_sync_[alloc|free|init|wait|...]() operating on this struct.
However, function ssam_request_sync() is one abstraction level above
this. Similarly, ssam_request_sync_with_buffer() is not a function
operating on struct ssam_request_sync, but rather a sibling to
ssam_request_sync(), both using the struct under the hood.
Therefore, rename the top level request functions:
ssam_request_sync() -> ssam_request_do_sync()
ssam_request_sync_with_buffer() -> ssam_request_do_sync_with_buffer()
ssam_request_sync_onstack() -> ssam_request_do_sync_onstack()
Link: https://lore.kernel.org/all/085e0ada65c11da9303d07e70c510dc45f21315b.1656756450.git.mchehab@kernel.org/
Link: https://github.com/sphinx-doc/sphinx/pull/8313
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20221220175608.1436273-2-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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Similar to the target category (TC), the target ID (TID) can be one
value out of a small number of choices, given in enum ssam_ssh_tid.
In the device ID macros, SSAM_SDEV() and SSAM_VDEV() we already use text
expansion to, both, remove some textual clutter for the target category
values and enforce that the value belongs to the known set. Now that we
know the names for the target IDs, use the same trick for them as well.
Also rename the SSAM_ANY_x macros to SSAM_SSH_x_ANY to better fit in.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20221202223327.690880-9-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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target and source IDs
The `tid_in` and `tid_out` fields of the serial hub protocol command
struct (struct ssh_command) are actually source and target IDs,
indicating the peer from which the message originated and the peer for
which it is intended.
Change the naming of those fields accordingly and improve the protocol
documentation. Additionally, introduce an enum containing all currently
known peers, i.e. targets and sources.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20221202223327.690880-3-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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The driver core is changing to pass some pointers as const, so move
to_ssam_device() to use container_of_const() to handle this change.
to_ssam_device() now properly keeps the const-ness of the pointer passed
into it, while as before it could be lost.
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230111113018.459199-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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module
Move helper functions for client device registration to the core module.
This simplifies addition of future DT/OF support and also allows us to
split out the device hub drivers into their own module.
At the same time, also improve device node validation a bit by not
silently skipping devices with invalid device UID specifiers. Further,
ensure proper lifetime management for the firmware/software nodes
associated with the added devices.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220624205800.1355621-2-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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and return value
Add helper macros for synchronous stack-allocated Surface Aggregator
request with both argument and return value, similar to the current
argument-only and return-value-only ones.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220624183642.910893-2-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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With the introduction of the Surface Laptop Studio, more event- and
target categories have been added. Therefore, increase the number of
reserved events and extend the enum of know target categories to
accommodate this.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220614194117.4118897-1-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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The KIP subsystem (full name unknown, abbreviation has been obtained
through reverse engineering) handles detachable peripherals such as the
keyboard cover on the Surface Pro X and Surface Pro 8.
It is currently not entirely clear what this subsystem entails, but at
the very least it provides event notifications for when the keyboard
cover on the Surface Pro X and Surface Pro 8 have been detached or
re-attached, as well as the state that the keyboard cover is currently
in (e.g. folded-back, folded laptop-like, closed, etc.).
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220527023447.2460025-9-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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unregistering
When SSAM client devices have been (physically) hot-removed,
communication attempts with those devices may fail and time out. This
can even extend to event notifiers, due to which timeouts may occur
during device removal, slowing down that process.
Add a parameter to the notifier unregister function that allows skipping
communication with the EC to prevent this. Furthermore, add wrappers for
registering and unregistering notifiers belonging to SSAM client devices
that automatically check if the device has been marked as hot-removed
and communication should be avoided.
Note that non-SSAM client devices can generally not be hot-removed, so
also add a convenience wrapper for those, defaulting to allow
communication.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220527023447.2460025-4-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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Some SSAM devices, notably the keyboard cover (keyboard and touchpad) on
the Surface Pro 8, can be hot-removed. When this occurs, communication
with the device may fail and time out. This timeout can unnecessarily
block and slow down device removal and even cause issues when the
devices are detached and re-attached quickly. Thus, communication should
generally be avoided once hot-removal is detected.
While we already remove a device as soon as we detect its (hot-)removal,
the corresponding device driver may still attempt to communicate with
the device during teardown. This is especially critical as communication
failure may also extend to disabling of events, which is typically done
at that stage.
Add a flag to allow marking devices as hot-removed. This can then be
used during client driver teardown to check if any communication
attempts should be avoided.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220527023447.2460025-3-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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CONFIG_SURFACE_AGGREGATOR_BUS is disabled
In SSAM subsystem drivers that handle both ACPI and SSAM-native client
devices, we may want to check whether we have a SSAM (native) client
device. Further, we may want to do this even when instantiation thereof
cannot happen due to CONFIG_SURFACE_AGGREGATOR_BUS=n. Currently, doing
so causes an error due to an undefined reference error due to
ssam_device_type being placed in the bus source unit.
Therefore, if CONFIG_SURFACE_AGGREGATOR_BUS is not defined, simply let
is_ssam_device() return false to prevent this error.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220527023447.2460025-2-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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Currently, there are similar functions defined in the Aggregator
Registry and the controller core.
Make client device removal more generic and export it. We can then use
this function later on to remove client devices from device hubs as well
as the controller and avoid re-defining similar things.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20211028002243.1586083-2-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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Until now, we have only ever seen the REG-category registry being used
on devices addressed with target ID 2. In fact, we have only ever seen
Surface Aggregator Module (SAM) HID devices with target ID 2. For those
devices, the registry also has to be addressed with target ID 2.
Some devices, like the new Surface Laptop Studio, however, address their
HID devices on target ID 1. As a result of this, any target ID 2
commands time out. This includes event management commands addressed to
the target ID 2 REG-category registry. For these devices, the registry
has to be addressed via target ID 1 instead.
We therefore assume that the target ID of the registry to be used
depends on the target ID of the respective device. Implement this
accordingly.
Note that we currently allow the surface HID driver to only load against
devices with target ID 2, so these timeouts are not happening (yet).
This is just a preparation step before we allow the driver to load
against all target IDs.
Cc: stable@vger.kernel.org # 5.14+
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20211021130904.862610-3-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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It's 2021, update the copyright accordingly.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210604134755.535590-4-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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We can already enable and disable SAM events via one of two ways: either
via a (non-observer) notifier tied to a specific event group, or a
generic event enable/disable request. In some instances, however,
neither method may be desirable.
The first method will tie the event enable request to a specific
notifier, however, when we want to receive notifications for multiple
event groups of the same target category and forward this to the same
notifier callback, we may receive duplicate events, i.e. one event per
registered notifier. The second method will bypass the internal
reference counting mechanism, meaning that a disable request will
disable the event regardless of any other client driver using it, which
may break the functionality of that driver.
To address this problem, add new functions that allow enabling and
disabling of events via the event reference counting mechanism built
into the controller, without needing to register a notifier.
This can then be used in combination with observer notifiers to process
multiple events of the same target category without duplication in the
same callback function.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210604134755.535590-3-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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events
Currently, each SSAM event notifier is directly tied to one group of
events. This makes sense as registering a notifier will automatically
take care of enabling the corresponding event group and normally drivers
only need notifications for a very limited number of events, associated
with different callbacks for each group.
However, there are rare cases, especially for debugging, when we want to
get notifications for a whole event target category instead of just a
single group of events in that category. Registering multiple notifiers,
i.e. one per group, may be infeasible due to two issues: a) we might not
know every event enable/disable specification as some events are
auto-enabled by the EC and b) forwarding this to the same callback will
lead to duplicate events as we might not know the full event
specification to perform the appropriate filtering.
This commit introduces observer-notifiers, which are notifiers that are
not tied to a specific event group and do not attempt to manage any
events. In other words, they can be registered without enabling any
event group or incrementing the corresponding reference count and just
act as silent observers, listening to all currently/previously enabled
events based on their match-specification.
Essentially, this allows us to register one single notifier for a full
event target category, meaning that we can process all events of that
target category in a single callback without duplication. Specifically,
this will be used in the cdev debug interface to forward events to
user-space via a device file from which the events can be read.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210604134755.535590-2-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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Clang complains about the assignment of SSAM_ANY_IID to
ssam_device_uid->instance:
drivers/platform/surface/surface_aggregator_registry.c:478:25: error: implicit conversion from 'int' to '__u8' (aka 'unsigned char') changes value from 65535 to 255 [-Werror,-Wconstant-conversion]
{ SSAM_VDEV(HUB, 0x02, SSAM_ANY_IID, 0x00) },
~ ^~~~~~~~~~~~
include/linux/surface_aggregator/device.h:71:23: note: expanded from macro 'SSAM_ANY_IID'
#define SSAM_ANY_IID 0xffff
^~~~~~
include/linux/surface_aggregator/device.h:126:63: note: expanded from macro 'SSAM_VDEV'
SSAM_DEVICE(SSAM_DOMAIN_VIRTUAL, SSAM_VIRTUAL_TC_##cat, tid, iid, fun)
^~~
include/linux/surface_aggregator/device.h:102:41: note: expanded from macro 'SSAM_DEVICE'
.instance = ((iid) != SSAM_ANY_IID) ? (iid) : 0, \
^~~
The assignment doesn't actually happen, but clang checks the type limits
before checking whether this assignment is reached. Replace the ?:
operator with a __builtin_choose_expr() invocation that avoids the
warning for the untaken part.
Fixes: eb0e90a82098 ("platform/surface: aggregator: Add dedicated bus and device type")
Cc: platform-driver-x86@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210514200453.1542978-1-arnd@kernel.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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functions
The SSAM_DEFINE_SYNC_REQUEST_x() macros are intended to reduce
boiler-plate code for SSAM request definitions by defining a wrapper
function for the specified request. The client device variants of those
macros, i.e. SSAM_DEFINE_SYNC_REQUEST_CL_x() in particular rely on the
multi-device (MD) variants, e.g.:
#define SSAM_DEFINE_SYNC_REQUEST_CL_R(name, rtype, spec...) \
SSAM_DEFINE_SYNC_REQUEST_MD_R(__raw_##name, rtype, spec) \
int name(struct ssam_device *sdev, rtype *ret) \
{ \
return __raw_##name(sdev->ctrl, sdev->uid.target, \
sdev->uid.instance, ret); \
}
This now creates the problem that it is not possible to declare the
generated functions static via
static SSAM_DEFINE_SYNC_REQUEST_CL_R(...)
as this will only apply to the function defined by the multi-device
macro, i.e. SSAM_DEFINE_SYNC_REQUEST_MD_R(). Thus compiling with
`-Wmissing-prototypes' rightfully complains that there is a 'static'
keyword missing.
To solve this, make all SSAM_DEFINE_SYNC_REQUEST_x() macros define
static functions. Non-client-device macros are also changed for
consistency. In general, we expect those functions to be only used
locally in the respective drivers for the corresponding interfaces, so
having to define a wrapper function to be able to export this should be
the odd case out.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: b78b4982d763 ("platform/surface: Add platform profile driver")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210304190524.1172197-1-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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The Surface Aggregator EC provides varying functionality, depending on
the Surface device. To manage this functionality, we use dedicated
client devices for each subsystem or virtual device of the EC. While
some of these clients are described as standard devices in ACPI and the
corresponding client drivers can be implemented as platform drivers in
the kernel (making use of the controller API already present), many
devices, especially on newer Surface models, cannot be found there.
To simplify management of these devices, we introduce a new bus and
client device type for the Surface Aggregator subsystem. The new device
type takes care of managing the controller reference, essentially
guaranteeing its validity for as long as the client device exists, thus
alleviating the need to manually establish device links for that purpose
in the client driver (as has to be done with the platform devices).
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20201221183959.1186143-7-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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Add Surface System Aggregator Module core and Surface Serial Hub driver,
required for the embedded controller found on Microsoft Surface devices.
The Surface System Aggregator Module (SSAM, SAM or Surface Aggregator)
is an embedded controller (EC) found on 4th and later generation
Microsoft Surface devices, with the exception of the Surface Go series.
This EC provides various functionality, depending on the device in
question. This can include battery status and thermal reporting (5th and
later generations), but also HID keyboard (6th+) and touchpad input
(7th+) on Surface Laptop and Surface Book 3 series devices.
This patch provides the basic necessities for communication with the SAM
EC on 5th and later generation devices. On these devices, the EC
provides an interface that acts as serial device, called the Surface
Serial Hub (SSH). 4th generation devices, on which the EC interface is
provided via an HID-over-I2C device, are not supported by this patch.
Specifically, this patch adds a driver for the SSH device (device HID
MSHW0084 in ACPI), as well as a controller structure and associated API.
This represents the functional core of the Surface Aggregator kernel
subsystem, introduced with this patch, and will be expanded upon in
subsequent commits.
The SSH driver acts as the main attachment point for this subsystem and
sets-up and manages the controller structure. The controller in turn
provides a basic communication interface, allowing to send requests from
host to EC and receiving the corresponding responses, as well as
managing and receiving events, sent from EC to host. It is structured
into multiple layers, with the top layer presenting the API used by
other kernel drivers and the lower layers modeled after the serial
protocol used for communication.
Said other drivers are then responsible for providing the (Surface model
specific) functionality accessible through the EC (e.g. battery status
reporting, thermal information, ...) via said controller structure and
API, and will be added in future commits.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20201221183959.1186143-2-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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