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8ca3246081
linux
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drivers
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nvmem
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internals.h
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nvmem: Create a header for internal sharing Before adding all the NVMEM layout bus infrastructure to the core, let's move the main nvmem_device structure in an internal header, only available to the core. This way all the additional code can be added in a dedicated file in order to keep the current core file tidy. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20231215111536.316972-4-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-15 11:15:29 +00:00
nvmem: Move and rename ->fixup_cell_info() 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 <miquel.raynal@bootlin.com> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20231215111536.316972-6-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-15 11:15:31 +00:00
nvmem: Create a header for internal sharing Before adding all the NVMEM layout bus infrastructure to the core, let's move the main nvmem_device structure in an internal header, only available to the core. This way all the additional code can be added in a dedicated file in order to keep the current core file tidy. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20231215111536.316972-4-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-15 11:15:29 +00:00
nvmem: core: Expose cells through sysfs 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 <miquel.raynal@bootlin.com> Tested-by: Rafał Miłecki <rafal@milecki.pl> Tested-by: Chen-Yu Tsai <wenst@chromium.org> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20231215111536.316972-9-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-15 11:15:34 +00:00
nvmem: Create a header for internal sharing Before adding all the NVMEM layout bus infrastructure to the core, let's move the main nvmem_device structure in an internal header, only available to the core. This way all the additional code can be added in a dedicated file in order to keep the current core file tidy. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20231215111536.316972-4-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-15 11:15:29 +00:00
nvmem: core: Rework layouts to become regular devices 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 <miquel.raynal@bootlin.com> Tested-by: Rafał Miłecki <rafal@milecki.pl> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20231215111536.316972-7-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-15 11:15:32 +00:00
nvmem: Create a header for internal sharing Before adding all the NVMEM layout bus infrastructure to the core, let's move the main nvmem_device structure in an internal header, only available to the core. This way all the additional code can be added in a dedicated file in order to keep the current core file tidy. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20231215111536.316972-4-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-15 11:15:29 +00:00
