@@ -20,11 +20,23 @@ static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot,
unsigned int magic)
{
int ret;
+ u8 *magic_ptr = (u8 *) &magic;
+ size_t cell_size;
struct nvmem_reboot_mode *nvmem_rbm;
nvmem_rbm = container_of(reboot, struct nvmem_reboot_mode, reboot);
- ret = nvmem_cell_write(nvmem_rbm->cell, &magic, sizeof(magic));
+ ret = nvmem_cell_get_size(nvmem_rbm->cell, &cell_size, NULL);
+ if (ret < 0) {
+ dev_err(reboot->dev, "failed to get reboot mode nvmem cell size\n");
+ return ret;
+ }
+
+ /* Use magic's low-order bytes when writing to a smaller cell. */
+ if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) && cell_size < sizeof(magic))
+ magic_ptr += sizeof(magic) - cell_size;
+
+ ret = nvmem_cell_write(nvmem_rbm->cell, magic_ptr, MIN(cell_size, sizeof(magic)));
if (ret < 0)
dev_err(reboot->dev, "update reboot mode bits failed\n");
Some devices, such as Qualcomm sa8775p, have an nvmem reboot mode cell that is only 1 byte, which resulted in nvmem_reboot_mode_write() failing when it attempts to write a 4-byte magic. Checking the nvmem cell size and writing only the lower bits of the reboot mode magic is needed for these devices. Signed-off-by: Jennifer Berringer <jberring@redhat.com> --- This patch depends on [1]. [1] https://lore.kernel.org/all/20250318094716.3053546-5-o.rempel@pengutronix.de/ Changes v5: - Switch to using nvmem_cell_get_size() from the above linked patch instead of introducing another function with the same purpose. --- drivers/power/reset/nvmem-reboot-mode.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)