kernel/drivers/mtd/ubi/nvmem.c, branch linux-rolling-stable

mtd: ubi: remove redundant check on bytes_left at end of function

2024-11-14T18:54:27Z

In function ubi_nvmem_reg_read the while-loop can only be exiting of bytes_left is zero or an error has occurred. There is an exit return path if an error occurs, so the bytes_left can only be zero after that point. Hence the check for a non-zero bytes_left at the end of the function is redundant and can be removed. Remove the check and just return 0. Signed-off-by: Colin Ian King Reviewed-by: Zhihao Cheng Signed-off-by: Richard Weinberger

mtd: ubi: avoid expensive do_div() on 32-bit machines

2024-07-12T17:46:21Z

The use of do_div() in ubi_nvmem_reg_read() makes calling it on 32-bit machines rather expensive. Since the 'from' variable is known to be a 32-bit quantity, it is clearly never needed and can be optimized into a regular division operation. Fixes: b8a77b9a5f9c ("mtd: ubi: fix NVMEM over UBI volumes on 32-bit systems") Fixes: 3ce485803da1 ("mtd: ubi: provide NVMEM layer over UBI volumes") Signed-off-by: Arnd Bergmann Reviewed-by: Zhihao Cheng Signed-off-by: Richard Weinberger

mtd: ubi: fix NVMEM over UBI volumes on 32-bit systems

2024-03-10T21:14:28Z

A compiler warning related to sizeof(int) != 8 when calling do_div() is triggered when building on 32-bit platforms. Address this by using integer types having a well-defined size. Fixes: 3ce485803da1 ("mtd: ubi: provide NVMEM layer over UBI volumes") Signed-off-by: Daniel Golle Reviewed-by: Zhihao Cheng Tested-by: Randy Dunlap Signed-off-by: Richard Weinberger

mtd: ubi: provide NVMEM layer over UBI volumes

2024-02-25T21:42:23Z

In an ideal world we would like UBI to be used where ever possible on a NAND chip. And with UBI support in ARM Trusted Firmware and U-Boot it is possible to achieve an (almost-)all-UBI flash layout. Hence the need for a way to also use UBI volumes to store board-level constants, such as MAC addresses and calibration data of wireless interfaces. Add UBI volume NVMEM driver module exposing UBI volumes as NVMEM providers. Allow UBI devices to have a "volumes" firmware subnode with volumes which may be compatible with "nvmem-cells". Access to UBI volumes via the NVMEM interface at this point is read-only, and it is slow, opening and closing the UBI volume for each access due to limitations of the NVMEM provider API. Signed-off-by: Daniel Golle Signed-off-by: Richard Weinberger