From b588e2d813c85a2ecbaf3d64269dfde4bb735917 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 22 Jan 2024 16:34:10 +0100 Subject: [PATCH] nvmem: include bit index in cell sysfs file name MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Rafał Miłecki Cc: Chen-Yu Tsai Cc: Srinivas Kandagatla Cc: Greg Kroah-Hartman Cc: asahi@lists.linux.dev Cc: Sven Peter Signed-off-by: Arnd Bergmann Signed-off-by: Srinivas Kandagatla --- Documentation/ABI/testing/sysfs-nvmem-cells | 16 ++++++++-------- drivers/nvmem/core.c | 5 +++-- 2 files changed, 11 insertions(+), 10 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-nvmem-cells b/Documentation/ABI/testing/sysfs-nvmem-cells index 7af70adf3690e3..c7c9444f92a880 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 Description: The "cells" folder contains one file per cell exposed by the - NVMEM device. The name of the file is: @, with - being the cell name and 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: "@,", + with being the cell name and 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 diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 980123fb4dde05..eb357ac2e54a2a 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -460,8 +460,9 @@ static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem) list_for_each_entry(entry, &nvmem->cells, node) { sysfs_bin_attr_init(&attrs[i]); attrs[i].attr.name = devm_kasprintf(&nvmem->dev, GFP_KERNEL, - "%s@%x", entry->name, - entry->offset); + "%s@%x,%x", entry->name, + entry->offset, + entry->bit_offset); attrs[i].attr.mode = 0444; attrs[i].size = entry->bytes; attrs[i].read = &nvmem_cell_attr_read;