kernel/drivers/nvmem/core.c, branch linux-6.9.y

nvmem: core: limit cell sysfs permissions to main attribute ones

2024-07-18T11:22:50Z

commit 6bef98bafd82903a8d461463f9594f19f1fd6a85 upstream. The cell sysfs attribute should not provide more access to the nvmem data than the main attribute itself. For example if nvme_config::root_only was set, the cell attribute would still provide read access to everybody. Mask out permissions not available on the main attribute. Fixes: 0331c611949f ("nvmem: core: Expose cells through sysfs") Cc: stable@vger.kernel.org Signed-off-by: Thomas Weißschuh Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20240628113704.13742-5-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

nvmem: core: only change name to fram for current attribute

2024-07-18T11:22:49Z

commit 0ba424c934fd43dccf0d597e1ae8851f07cb2edf upstream. bin_attr_nvmem_eeprom_compat is the template from which all future compat attributes are created. Changing it means to change all subsquent compat attributes, too. Instead only use the "fram" name for the currently registered attribute. Fixes: fd307a4ad332 ("nvmem: prepare basics for FRAM support") Cc: stable@vger.kernel.org Signed-off-by: Thomas Weißschuh Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20240628113704.13742-4-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

nvmem: core: Print error on wrong bits DT property

2024-03-07T20:21:53Z

The algorithms in nvmem core are built with the constraint that bit_offset < 8. If bit_offset is greater the results are wrong. Print an error if the devicetree 'bits' property is outside of the valid range and abort parsing. Signed-off-by: Markus Schneider-Pargmann Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20240224114516.86365-12-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

nvmem: include bit index in cell sysfs file name

2024-02-14T15:28:16Z

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: Cc: Miquel Raynal Cc: Rafał Miłecki Cc: Chen-Yu Tsai Cc: Srinivas Kandagatla Cc: Greg Kroah-Hartman Cc: Cc: Sven Peter Signed-off-by: Arnd Bergmann Signed-off-by: Srinivas Kandagatla Reviewed-by: Eric Curtin Reviewed-by: Miquel Raynal Link: https://lore.kernel.org/r/20240209163454.98051-1-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

nvmem: core: add nvmem_dev_size() helper

2024-01-04T16:01:13Z

This is required by layouts that need to read whole NVMEM content. It's especially useful for NVMEM devices without hardcoded layout (like U-Boot environment data block). Signed-off-by: Rafał Miłecki Reviewed-by: Miquel Raynal Link: https://lore.kernel.org/r/20231221173421.13737-2-zajec5@gmail.com Signed-off-by: Greg Kroah-Hartman

nvmem: drop nvmem_layout_get_match_data()

2024-01-04T16:01:13Z

Thanks for layouts refactoring we now have "struct device" associated with layout. Also its OF pointer points directly to the "nvmem-layout" DT node. All it takes to get match data is a generic of_device_get_match_data(). Signed-off-by: Rafał Miłecki Reviewed-by: Miquel Raynal Reviewed-by: Michael Walle Link: https://lore.kernel.org/r/20231219120104.3422-2-zajec5@gmail.com Signed-off-by: Greg Kroah-Hartman

nvmem: layouts: refactor .add_cells() callback arguments

2024-01-04T16:01:13Z

Simply pass whole "struct nvmem_layout" instead of single variables. There is nothing in "struct nvmem_layout" that we have to hide from layout drivers. They also access it during .probe() and .remove(). Thanks to this change: 1. API gets more consistent All layouts drivers callbacks get the same argument 2. Layouts get correct device Before this change NVMEM core code was passing NVMEM device instead of layout device. That resulted in: * Confusing prints * Calling devm_*() helpers on wrong device * Helpers like of_device_get_match_data() dereferencing NULLs 3. It gets possible to get match data First of all nvmem_layout_get_match_data() requires passing "struct nvmem_layout" which .add_cells() callback didn't have before this. It doesn't matter much as it's rather useless now anyway (and will be dropped). What's more important however is that of_device_get_match_data() can be used now thanks to owning a proper device pointer. Signed-off-by: Rafał Miłecki Reviewed-by: Miquel Raynal Reviewed-by: Michael Walle Link: https://lore.kernel.org/r/20231219120104.3422-1-zajec5@gmail.com Signed-off-by: Greg Kroah-Hartman

nvmem: core: Expose cells through sysfs

2023-12-15T12:30:08Z

The binary content of nvmem devices is available to the user so in the easiest cases, finding the content of a cell is rather easy as it is just a matter of looking at a known and fixed offset. However, nvmem layouts have been recently introduced to cope with more advanced situations, where the offset and size of the cells is not known in advance or is dynamic. When using layouts, more advanced parsers are used by the kernel in order to give direct access to the content of each cell, regardless of its position/size in the underlying device. Unfortunately, these information are not accessible by users, unless by fully re-implementing the parser logic in userland. Let's expose the cells and their content through sysfs to avoid these situations. Of course the relevant NVMEM sysfs Kconfig option must be enabled for this support to be available. Not all nvmem devices expose cells. Indeed, the .bin_attrs attribute group member will be filled at runtime only when relevant and will remain empty otherwise. In this case, as the cells attribute group will be empty, it will not lead to any additional folder/file creation. Exposed cells are read-only. There is, in practice, everything in the core to support a write path, but as I don't see any need for that, I prefer to keep the interface simple (and probably safer). The interface is documented as being in the "testing" state which means we can later add a write attribute if though relevant. Signed-off-by: Miquel Raynal Tested-by: Rafał Miłecki Tested-by: Chen-Yu Tsai Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20231215111536.316972-9-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

nvmem: core: Rework layouts to become regular devices

2023-12-15T12:30:07Z

Current layout support was initially written without modules support in mind. When the requirement for module support rose, the existing base was improved to adopt modularization support, but kind of a design flaw was introduced. With the existing implementation, when a storage device registers into NVMEM, the core tries to hook a layout (if any) and populates its cells immediately. This means, if the hardware description expects a layout to be hooked up, but no driver was provided for that, the storage medium will fail to probe and try later from scratch. Even if we consider that the hardware description shall be correct, we could still probe the storage device (especially if it contains the rootfs). One way to overcome this situation is to consider the layouts as devices, and leverage the native notifier mechanism. When a new NVMEM device is registered, we can populate its nvmem-layout child, if any, and wait for the matching to be done in order to get the cells (the waiting can be easily done with the NVMEM notifiers). If the layout driver is compiled as a module, it should automatically be loaded. This way, there is no strong order to enforce, any NVMEM device creation or NVMEM layout driver insertion will be observed as a new event which may lead to the creation of additional cells, without disturbing the probes with costly (and sometimes endless) deferrals. In order to achieve that goal we create a new bus for the nvmem-layouts with minimal logic to match nvmem-layout devices with nvmem-layout drivers. All this infrastructure code is created in the layouts.c file. Signed-off-by: Miquel Raynal Tested-by: Rafał Miłecki Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20231215111536.316972-7-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman

nvmem: Move and rename ->fixup_cell_info()

2023-12-15T12:30:07Z

This hook is meant to be used by any provider and instantiating a layout just for this is useless. Let's instead move this hook to the nvmem device and add it to the config structure to be easily shared by the providers. While at moving this hook, rename it ->fixup_dt_cell_info() to clarify its main intended purpose. Signed-off-by: Miquel Raynal Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20231215111536.316972-6-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman