| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <0abce5f8-2688-451d-8c70-8fc32c73f8be@linaro.org>
Date: Fri, 24 Nov 2023 21:53:52 +0200
From: Tudor Ambarus <tudor.ambarus@...aro.org>
To: pratyush@...nel.org, michael@...le.cc, bagasdotme@...il.com
Cc: linux-mtd@...ts.infradead.org, linux-doc@...r.kernel.org,
corbet@....net, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] docs: mtd: spi-nor: add sections about flash
additions and testing
On 24.11.2023 20:49, Tudor Ambarus wrote:
> Add sections about how to propose a new flash addition and about the
> minimum testing requirements.
>
> Signed-off-by: Tudor Ambarus <tudor.ambarus@...aro.org>
> Reviewed-by: Michael Walle <michael@...le.cc>
> Reviewed-by: Pratyush Yadav <pratyush@...nel.org>
> ---
> Documentation/driver-api/mtd/spi-nor.rst | 187 +++++++++++++++++++++++
> 1 file changed, 187 insertions(+)
>
> diff --git a/Documentation/driver-api/mtd/spi-nor.rst b/Documentation/driver-api/mtd/spi-nor.rst
> index c22f8c0f7950..3b2e1a6a88bf 100644
> --- a/Documentation/driver-api/mtd/spi-nor.rst
> +++ b/Documentation/driver-api/mtd/spi-nor.rst
> @@ -63,3 +63,190 @@ 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.
> +
> +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
it's not enough. If the flash comes erased by default, and erase opcode
is ignored, we won't catch it. Thus we'll need a second erase, after we
verify the write.
> +
> + 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
here again:
root@1:~# mtd_debug erase /dev/mtd0 0 2097152
root@1:~# mtd_debug read /dev/mtd0 0 2097152 spi_read
root@1:~# sha256sum spi_read
> +
> + 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
Powered by blists - more mailing lists