Changes in internals.h

0331c611 - nvmem: core: Expose cells through sysfs

Fri, 15 Dec 2023 11:15:34 +0000

nvmem: core: Expose cells through sysfsThe binary content of nvmem devices is available to the user so in theeasiest cases, finding the content of a cell is rather easy as it isjust a matter of looking at a known and fixed offset. However, nvmemlayouts have been recently introduced to cope with more advancedsituations, where the offset and size of the cells is not known inadvance or is dynamic. When using layouts, more advanced parsers areused by the kernel in order to give direct access to the content of eachcell, regardless of its position/size in the underlyingdevice. 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 thesesituations. Of course the relevant NVMEM sysfs Kconfig option must beenabled for this support to be available.Not all nvmem devices expose cells. Indeed, the .bin_attrs attributegroup member will be filled at runtime only when relevant and willremain empty otherwise. In this case, as the cells attribute group willbe empty, it will not lead to any additional folder/file creation.Exposed cells are read-only. There is, in practice, everything in thecore to support a write path, but as I don't see any need for that, Iprefer to keep the interface simple (and probably safer). The interfaceis documented as being in the "testing" state which means we can lateradd 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.orgSigned-off-by: Greg Kroah-Hartman List of files: /linux-6.15/drivers/nvmem/internals.h

fc29fd82 - nvmem: core: Rework layouts to become regular devices

Fri, 15 Dec 2023 11:15:32 +0000

nvmem: core: Rework layouts to become regular devicesCurrent layout support was initially written without modules support inmind. When the requirement for module support rose, the existing basewas improved to adopt modularization support, but kind of a design flawwas introduced. With the existing implementation, when a storage deviceregisters into NVMEM, the core tries to hook a layout (if any) andpopulates its cells immediately. This means, if the hardware descriptionexpects a layout to be hooked up, but no driver was provided for that,the storage medium will fail to probe and try later fromscratch. Even if we consider that the hardware description shall becorrect, we could still probe the storage device (especially if itcontains the rootfs).One way to overcome this situation is to consider the layouts asdevices, and leverage the native notifier mechanism. When a new NVMEMdevice 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 (thewaiting can be easily done with the NVMEM notifiers). If the layoutdriver is compiled as a module, it should automatically be loaded. Thisway, there is no strong order to enforce, any NVMEM device creationor NVMEM layout driver insertion will be observed as a new event whichmay lead to the creation of additional cells, without disturbing theprobes with costly (and sometimes endless) deferrals.In order to achieve that goal we create a new bus for the nvmem-layoutswith minimal logic to match nvmem-layout devices with nvmem-layoutdrivers. 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.orgSigned-off-by: Greg Kroah-Hartman List of files: /linux-6.15/drivers/nvmem/internals.h

1172460e - nvmem: Move and rename ->fixup_cell_info()

Fri, 15 Dec 2023 11:15:31 +0000

nvmem: Move and rename ->fixup_cell_info()This hook is meant to be used by any provider and instantiating a layoutjust for this is useless. Let's instead move this hook to the nvmemdevice and add it to the config structure to be easily shared by theproviders.While at moving this hook, rename it ->fixup_dt_cell_info() to clarifyits 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.orgSigned-off-by: Greg Kroah-Hartman List of files: /linux-6.15/drivers/nvmem/internals.h

ec9c08a1 - nvmem: Create a header for internal sharing

Fri, 15 Dec 2023 11:15:29 +0000

nvmem: Create a header for internal sharingBefore adding all the NVMEM layout bus infrastructure to the core, let'smove the main nvmem_device structure in an internal header, onlyavailable to the core. This way all the additional code can be added ina dedicated file in order to keep the current core file tidy.Signed-off-by: Miquel Raynal Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20231215111536.316972-4-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman List of files: /linux-6.15/drivers/nvmem/internals.h