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authorArnd Bergmann <arnd@arndb.de>2024-02-09 16:34:54 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-02-14 16:28:16 +0100
commite20f378d993b1034eebe3ae78e67f3ed10e75356 (patch)
tree4cd371c28eb13169ee0073e453868e80748b4bdb /Documentation/ABI
parent23d62fb5d368b56fbfede3757c061d5de410a9b8 (diff)
nvmem: include bit index in cell sysfs file name
Creating sysfs files for all Cells caused a boot failure for linux-6.8-rc1 on Apple M1, which (in downstream dts files) has multiple nvmem cells that use the same byte address. This causes the device probe to fail with [ 0.605336] sysfs: cannot create duplicate filename '/devices/platform/soc@200000000/2922bc000.efuse/apple_efuses_nvmem0/cells/efuse@a10' [ 0.605347] CPU: 7 PID: 1 Comm: swapper/0 Tainted: G S 6.8.0-rc1-arnd-5+ #133 [ 0.605355] Hardware name: Apple Mac Studio (M1 Ultra, 2022) (DT) [ 0.605362] Call trace: [ 0.605365] show_stack+0x18/0x2c [ 0.605374] dump_stack_lvl+0x60/0x80 [ 0.605383] dump_stack+0x18/0x24 [ 0.605388] sysfs_warn_dup+0x64/0x80 [ 0.605395] sysfs_add_bin_file_mode_ns+0xb0/0xd4 [ 0.605402] internal_create_group+0x268/0x404 [ 0.605409] sysfs_create_groups+0x38/0x94 [ 0.605415] devm_device_add_groups+0x50/0x94 [ 0.605572] nvmem_populate_sysfs_cells+0x180/0x1b0 [ 0.605682] nvmem_register+0x38c/0x470 [ 0.605789] devm_nvmem_register+0x1c/0x6c [ 0.605895] apple_efuses_probe+0xe4/0x120 [ 0.606000] platform_probe+0xa8/0xd0 As far as I can tell, this is a problem for any device with multiple cells on different bits of the same address. Avoid the issue by changing the file name to include the first bit number. Fixes: 0331c611949f ("nvmem: core: Expose cells through sysfs") Link: https://github.com/AsahiLinux/linux/blob/bd0a1a7d4/arch/arm64/boot/dts/apple/t600x-dieX.dtsi#L156 Cc: <regressions@lists.linux.dev> Cc: Miquel Raynal <miquel.raynal@bootlin.com> Cc: Rafał Miłecki <rafal@milecki.pl> Cc: Chen-Yu Tsai <wenst@chromium.org> Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: <asahi@lists.linux.dev> Cc: Sven Peter <sven@svenpeter.dev> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Reviewed-by: Eric Curtin <ecurtin@redhat.com> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20240209163454.98051-1-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/sysfs-nvmem-cells16
1 files changed, 8 insertions, 8 deletions
diff --git a/Documentation/ABI/testing/sysfs-nvmem-cells b/Documentation/ABI/testing/sysfs-nvmem-cells
index 7af70adf3690..c7c9444f92a8 100644
--- a/Documentation/ABI/testing/sysfs-nvmem-cells
+++ b/Documentation/ABI/testing/sysfs-nvmem-cells
@@ -4,18 +4,18 @@ KernelVersion: 6.5
Contact: Miquel Raynal <miquel.raynal@bootlin.com>
Description:
The "cells" folder contains one file per cell exposed by the
- NVMEM device. The name of the file is: <name>@<where>, with
- <name> being the cell name and <where> its location in the NVMEM
- device, in hexadecimal (without the '0x' prefix, to mimic device
- tree node names). The length of the file is the size of the cell
- (when known). The content of the file is the binary content of
- the cell (may sometimes be ASCII, likely without trailing
- character).
+ NVMEM device. The name of the file is: "<name>@<byte>,<bit>",
+ with <name> being the cell name and <where> its location in
+ the NVMEM device, in hexadecimal bytes and bits (without the
+ '0x' prefix, to mimic device tree node names). The length of
+ the file is the size of the cell (when known). The content of
+ the file is the binary content of the cell (may sometimes be
+ ASCII, likely without trailing character).
Note: This file is only present if CONFIG_NVMEM_SYSFS
is enabled.
Example::
- hexdump -C /sys/bus/nvmem/devices/1-00563/cells/product-name@d
+ hexdump -C /sys/bus/nvmem/devices/1-00563/cells/product-name@d,0
00000000 54 4e 34 38 4d 2d 50 2d 44 4e |TN48M-P-DN|
0000000a