diff options
Diffstat (limited to 'Documentation/driver-api/mtd')
| -rw-r--r-- | Documentation/driver-api/mtd/index.rst | 2 | ||||
| -rw-r--r-- | Documentation/driver-api/mtd/nand_ecc.rst | 2 | ||||
| -rw-r--r-- | Documentation/driver-api/mtd/spi-intel.rst (renamed from Documentation/driver-api/mtd/intel-spi.rst) | 12 | ||||
| -rw-r--r-- | Documentation/driver-api/mtd/spi-nor.rst | 263 |
4 files changed, 209 insertions, 70 deletions
diff --git a/Documentation/driver-api/mtd/index.rst b/Documentation/driver-api/mtd/index.rst index 436ba5a851d7..6a4278f409d7 100644 --- a/Documentation/driver-api/mtd/index.rst +++ b/Documentation/driver-api/mtd/index.rst @@ -7,6 +7,6 @@ Memory Technology Device (MTD) .. toctree:: :maxdepth: 1 - intel-spi + spi-intel nand_ecc spi-nor diff --git a/Documentation/driver-api/mtd/nand_ecc.rst b/Documentation/driver-api/mtd/nand_ecc.rst index e8d3c53a5056..74347c14a70b 100644 --- a/Documentation/driver-api/mtd/nand_ecc.rst +++ b/Documentation/driver-api/mtd/nand_ecc.rst @@ -5,7 +5,7 @@ NAND Error-correction Code Introduction ============ -Having looked at the linux mtd/nand driver and more specific at nand_ecc.c +Having looked at the linux mtd/nand Hamming software ECC engine driver I felt there was room for optimisation. I bashed the code for a few hours performing tricks like table lookup removing superfluous code etc. After that the speed was increased by 35-40%. diff --git a/Documentation/driver-api/mtd/intel-spi.rst b/Documentation/driver-api/mtd/spi-intel.rst index 0e6d9cd5388d..df854f20ead1 100644 --- a/Documentation/driver-api/mtd/intel-spi.rst +++ b/Documentation/driver-api/mtd/spi-intel.rst @@ -1,5 +1,5 @@ ============================== -Upgrading BIOS using intel-spi +Upgrading BIOS using spi-intel ============================== Many Intel CPUs like Baytrail and Braswell include SPI serial flash host @@ -11,12 +11,12 @@ avoid accidental (or on purpose) overwrite of the content. Not all manufacturers protect the SPI serial flash, mainly because it allows upgrading the BIOS image directly from an OS. -The intel-spi driver makes it possible to read and write the SPI serial +The spi-intel driver makes it possible to read and write the SPI serial flash, if certain protection bits are not set and locked. If it finds any of them set, the whole MTD device is made read-only to prevent partial overwrites. By default the driver exposes SPI serial flash contents as read-only but it can be changed from kernel command line, -passing "intel-spi.writeable=1". +passing "spi_intel.writeable=1". Please keep in mind that overwriting the BIOS image on SPI serial flash might render the machine unbootable and requires special equipment like @@ -32,7 +32,7 @@ Linux. serial flash. Distros like Debian and Fedora have this prepackaged with name "mtd-utils". - 3) Add "intel-spi.writeable=1" to the kernel command line and reboot + 3) Add "spi_intel.writeable=1" to the kernel command line and reboot the board (you can also reload the driver passing "writeable=1" as module parameter to modprobe). @@ -52,7 +52,7 @@ Linux. 16384+0 records out 8388608 bytes (8.4 MB) copied, 10.0269 s, 837 kB/s - 6) Verify the backup: + 6) Verify the backup:: # sha1sum /dev/mtd0ro bios.bak fdbb011920572ca6c991377c4b418a0502668b73 /dev/mtd0ro @@ -66,7 +66,7 @@ Linux. # flash_erase /dev/mtd0 0 0 Erasing 4 Kibyte @ 7ff000 -- 100 % complete - 8) Once completed without errors you can write the new BIOS image: + 8) Once completed without errors you can write the new BIOS image:: # dd if=MNW2MAX1.X64.0092.R01.1605221712.bin of=/dev/mtd0 diff --git a/Documentation/driver-api/mtd/spi-nor.rst b/Documentation/driver-api/mtd/spi-nor.rst index 1f0437676762..148fa4288760 100644 --- a/Documentation/driver-api/mtd/spi-nor.rst +++ b/Documentation/driver-api/mtd/spi-nor.rst @@ -2,65 +2,204 @@ SPI NOR framework ================= -Part I - Why do we need this framework? ---------------------------------------- - -SPI bus controllers (drivers/spi/) only deal with streams of bytes; the bus -controller operates agnostic of the specific device attached. However, some -controllers (such as Freescale's QuadSPI controller) cannot easily handle -arbitrary streams of bytes, but rather are designed specifically for SPI NOR. - -In particular, Freescale's QuadSPI controller must know the NOR commands to -find the right LUT sequence. Unfortunately, the SPI subsystem has no notion of -opcodes, addresses, or data payloads; a SPI controller simply knows to send or -receive bytes (Tx and Rx). Therefore, we must define a new layering scheme under -which the controller driver is aware of the opcodes, addressing, and other -details of the SPI NOR protocol. - -Part II - How does the framework work? --------------------------------------- - -This framework just adds a new layer between the MTD and the SPI bus driver. -With this new layer, the SPI NOR controller driver does not depend on the -m25p80 code anymore. - -Before this framework, the layer is like:: - - MTD - ------------------------ - m25p80 - ------------------------ - SPI bus driver - ------------------------ - SPI NOR chip - - After this framework, the layer is like: - MTD - ------------------------ - SPI NOR framework - ------------------------ - m25p80 - ------------------------ - SPI bus driver - ------------------------ - SPI NOR chip - - With the SPI NOR controller driver (Freescale QuadSPI), it looks like: - MTD - ------------------------ - SPI NOR framework - ------------------------ - fsl-quadSPI - ------------------------ - SPI NOR chip - -Part III - How can drivers use the framework? ---------------------------------------------- - -The main API is spi_nor_scan(). Before you call the hook, a driver should -initialize the necessary fields for spi_nor{}. Please see -drivers/mtd/spi-nor/spi-nor.c for detail. Please also refer to spi-fsl-qspi.c -when you want to write a new driver for a SPI NOR controller. -Another API is spi_nor_restore(), this is used to restore the status of SPI -flash chip such as addressing mode. Call it whenever detach the driver from -device or reboot the system. +How to propose a new flash addition +----------------------------------- + +Most SPI NOR flashes comply with the JEDEC JESD216 +Serial Flash Discoverable Parameter (SFDP) standard. SFDP describes +the functional and feature capabilities of serial flash devices in a +standard set of internal read-only parameter tables. + +The SPI NOR driver queries the SFDP tables in order to determine the +flash's parameters and settings. If the flash defines the SFDP tables +it's likely that you won't need a flash entry at all, and instead +rely on the generic flash driver which probes the flash solely based +on its SFDP data. All one has to do is to specify the "jedec,spi-nor" +compatible in the device tree. + +There are cases however where you need to define an explicit flash +entry. This typically happens when the flash has settings or support +that is not covered by the SFDP tables (e.g. Block Protection), or +when the flash contains mangled SFDP data. If the later, one needs +to implement the ``spi_nor_fixups`` hooks in order to amend the SFDP +parameters with the correct values. + +Minimum testing requirements +----------------------------- + +Do all the tests from below and paste them in the commit's comments +section, after the ``---`` marker. + +1) Specify the controller that you used to test the flash and specify + the frequency at which the flash was operated, e.g.:: + + This flash is populated on the X board and was tested at Y + frequency using the Z (put compatible) SPI controller. + +2) Dump the sysfs entries and print the md5/sha1/sha256 SFDP checksum:: + + root@1:~# cat /sys/bus/spi/devices/spi0.0/spi-nor/partname + sst26vf064b + root@1:~# cat /sys/bus/spi/devices/spi0.0/spi-nor/jedec_id + bf2643 + root@1:~# cat /sys/bus/spi/devices/spi0.0/spi-nor/manufacturer + sst + root@1:~# xxd -p /sys/bus/spi/devices/spi0.0/spi-nor/sfdp + 53464450060102ff00060110300000ff81000106000100ffbf0001180002 + 0001fffffffffffffffffffffffffffffffffd20f1ffffffff0344eb086b + 083b80bbfeffffffffff00ffffff440b0c200dd80fd810d820914824806f + 1d81ed0f773830b030b0f7ffffff29c25cfff030c080ffffffffffffffff + ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff + ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff + ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff + ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff + ffffffffffffffffffffffffffffffffff0004fff37f0000f57f0000f9ff + 7d00f57f0000f37f0000ffffffffffffffffffffffffffffffffffffffff + ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff + ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff + ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff + ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff + ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff + ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff + ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff + ffffbf2643ffb95ffdff30f260f332ff0a122346ff0f19320f1919ffffff + ffffffff00669938ff05013506040232b03072428de89888a585c09faf5a + ffff06ec060c0003080bffffffffff07ffff0202ff060300fdfd040700fc + 0300fefe0202070e + root@1:~# sha256sum /sys/bus/spi/devices/spi0.0/spi-nor/sfdp + 428f34d0461876f189ac97f93e68a05fa6428c6650b3b7baf736a921e5898ed1 /sys/bus/spi/devices/spi0.0/spi-nor/sfdp + + Please dump the SFDP tables using ``xxd -p``. It enables us to do + the reverse operation and convert the hexdump to binary with + ``xxd -rp``. Dumping the SFDP data with ``hexdump -Cv`` is accepted, + but less desirable. + +3) Dump debugfs data:: + + root@1:~# cat /sys/kernel/debug/spi-nor/spi0.0/capabilities + Supported read modes by the flash + 1S-1S-1S + opcode 0x03 + mode cycles 0 + dummy cycles 0 + 1S-1S-1S (fast read) + opcode 0x0b + mode cycles 0 + dummy cycles 8 + 1S-1S-2S + opcode 0x3b + mode cycles 0 + dummy cycles 8 + 1S-2S-2S + opcode 0xbb + mode cycles 4 + dummy cycles 0 + 1S-1S-4S + opcode 0x6b + mode cycles 0 + dummy cycles 8 + 1S-4S-4S + opcode 0xeb + mode cycles 2 + dummy cycles 4 + 4S-4S-4S + opcode 0x0b + mode cycles 2 + dummy cycles 4 + + Supported page program modes by the flash + 1S-1S-1S + opcode 0x02 + + root@1:~# cat /sys/kernel/debug/spi-nor/spi0.0/params + name sst26vf064b + id bf 26 43 bf 26 43 + size 8.00 MiB + write size 1 + page size 256 + address nbytes 3 + flags HAS_LOCK | HAS_16BIT_SR | SOFT_RESET | SWP_IS_VOLATILE + + opcodes + read 0xeb + dummy cycles 6 + erase 0x20 + program 0x02 + 8D extension none + + protocols + read 1S-4S-4S + write 1S-1S-1S + register 1S-1S-1S + + erase commands + 20 (4.00 KiB) [0] + d8 (8.00 KiB) [1] + d8 (32.0 KiB) [2] + d8 (64.0 KiB) [3] + c7 (8.00 MiB) + + sector map + region (in hex) | erase mask | flags + ------------------+------------+---------- + 00000000-00007fff | [01 ] | + 00008000-0000ffff | [0 2 ] | + 00010000-007effff | [0 3] | + 007f0000-007f7fff | [0 2 ] | + 007f8000-007fffff | [01 ] | + +4) Use `mtd-utils <https://git.infradead.org/mtd-utils.git>`__ + and verify that erase, read and page program operations work fine:: + + root@1:~# dd if=/dev/urandom of=./spi_test bs=1M count=2 + 2+0 records in + 2+0 records out + 2097152 bytes (2.1 MB, 2.0 MiB) copied, 0.848566 s, 2.5 MB/s + + root@1:~# mtd_debug erase /dev/mtd0 0 2097152 + Erased 2097152 bytes from address 0x00000000 in flash + + root@1:~# mtd_debug read /dev/mtd0 0 2097152 spi_read + Copied 2097152 bytes from address 0x00000000 in flash to spi_read + + root@1:~# hexdump spi_read + 0000000 ffff ffff ffff ffff ffff ffff ffff ffff + * + 0200000 + + root@1:~# sha256sum spi_read + 4bda3a28f4ffe603c0ec1258c0034d65a1a0d35ab7bd523a834608adabf03cc5 spi_read + + root@1:~# mtd_debug write /dev/mtd0 0 2097152 spi_test + Copied 2097152 bytes from spi_test to address 0x00000000 in flash + + root@1:~# mtd_debug read /dev/mtd0 0 2097152 spi_read + Copied 2097152 bytes from address 0x00000000 in flash to spi_read + + root@1:~# sha256sum spi* + c444216a6ba2a4a66cccd60a0dd062bce4b865dd52b200ef5e21838c4b899ac8 spi_read + c444216a6ba2a4a66cccd60a0dd062bce4b865dd52b200ef5e21838c4b899ac8 spi_test + + If the flash comes erased by default and the previous erase was ignored, + we won't catch it, thus test the erase again:: + + root@1:~# mtd_debug erase /dev/mtd0 0 2097152 + Erased 2097152 bytes from address 0x00000000 in flash + + root@1:~# mtd_debug read /dev/mtd0 0 2097152 spi_read + Copied 2097152 bytes from address 0x00000000 in flash to spi_read + + root@1:~# sha256sum spi* + 4bda3a28f4ffe603c0ec1258c0034d65a1a0d35ab7bd523a834608adabf03cc5 spi_read + c444216a6ba2a4a66cccd60a0dd062bce4b865dd52b200ef5e21838c4b899ac8 spi_test + + Dump some other relevant data:: + + root@1:~# mtd_debug info /dev/mtd0 + mtd.type = MTD_NORFLASH + mtd.flags = MTD_CAP_NORFLASH + mtd.size = 8388608 (8M) + mtd.erasesize = 4096 (4K) + mtd.writesize = 1 + mtd.oobsize = 0 + regions = 0 |