On Tue Feb 17, 2026 at 4:51 PM IST, Anurag Dutta wrote:
> From: Santhosh Kumar K <[email protected]>
>
> Implement bad block skipping functionality in SPL MTD loader to ensure
> reliable boot from flash devices with bad blocks. Without this, the
> SPL would fail to load images if bad blocks were encountered.
>
> Signed-off-by: Santhosh Kumar K <[email protected]>
> Signed-off-by: Anurag Dutta <[email protected]>
> ---
> common/spl/spl_mtd.c | 78 ++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 68 insertions(+), 10 deletions(-)
>
> diff --git a/common/spl/spl_mtd.c b/common/spl/spl_mtd.c
> index 95c0c8ce8cd..d635aa2b476 100644
> --- a/common/spl/spl_mtd.c
> +++ b/common/spl/spl_mtd.c
> @@ -17,15 +17,64 @@ uint32_t __weak spl_mtd_get_uboot_offs(void)
> return CONFIG_SYS_MTD_U_BOOT_OFFS;
> }
>
> +static ulong spl_mtd_read_skip_bad(struct mtd_info *mtd, loff_t offs,
> + size_t size, void *dst)
> +{
> + size_t remaining = size;
> + size_t ret_len;
> + loff_t current_offs = offs;
NIT: Do we really need to have a current_offs here when we aren't gonna
use offs later anyway? Would be more clear to use offs directly imo.
> + loff_t block_aligned_offs, next_block;
> + u_char *buf = (u_char *)dst;
> + int err;
> +
> + while (remaining > 0) {
> + size_t read_size;
> + size_t block_remaining;
> +
> + block_aligned_offs = current_offs & ~(mtd->erasesize - 1);
We could make use of ALIGN macro here.
> +
> + if (mtd_block_isbad(mtd, block_aligned_offs)) {
> + debug("SPL: Skipping bad block at 0x%llx, jumping to
> 0x%llx\n",
> + block_aligned_offs, next_block);
On the first bad bock, next_block would be uninitialized data and
printing it here doesn't make sense.
> +
> + next_block = block_aligned_offs + mtd->erasesize;
> + current_offs = next_block;
> + continue;
> + }
> +
> + block_remaining = mtd->erasesize -
> + (current_offs & (mtd->erasesize - 1));
> + read_size = remaining < block_remaining ? remaining :
> block_remaining;
We could instead do 'read_size = min(remaining, block_remaining).
> +
> + err = mtd_read(mtd, current_offs, read_size, &ret_len, buf);
> + if (err) {
> + printf("SPL: Read error at offset 0x%llx: %d\n",
> + current_offs, err);
> + return size - remaining;
> + }
> +
> + buf += ret_len;
> + current_offs += ret_len;
> + remaining -= ret_len;
> +
> + if (current_offs >= mtd->size) {
> + printf("SPL: Reached end of device, read %zu/%zu
> bytes\n",
> + size - remaining, size);
> + break;
> + }
> + }
> +
> + return size - remaining;
> +}
> +
> static ulong spl_mtd_fit_read(struct spl_load_info *load, ulong offs,
> ulong size, void *dst)
> {
> struct mtd_info *mtd = load->priv;
> - int err;
> size_t ret_len;
>
> - err = mtd_read(mtd, offs, size, &ret_len, dst);
> - if (!err)
> + ret_len = spl_mtd_read_skip_bad(mtd, offs, size, dst);
> + if (ret_len > 0)
> return ret_len;
>
> return 0;
> @@ -52,17 +101,19 @@ struct mtd_info *spl_prepare_mtd(uint boot_device)
> int spl_mtd_load(struct spl_image_info *spl_image,
> struct mtd_info *mtd, struct spl_boot_device *bootdev)
> {
> - int err;
> + int err = 0;
> struct legacy_img_hdr *header;
> __maybe_unused struct spl_load_info load;
> size_t ret_len;
>
> header = spl_get_load_buffer(0, sizeof(*header));
> -
> - err = mtd_read(mtd, spl_mtd_get_uboot_offs(), sizeof(*header),
> - &ret_len, (void *)header);
> - if (err)
> + ret_len = spl_mtd_read_skip_bad(mtd, spl_mtd_get_uboot_offs(),
> + sizeof(*header), (void *)header);
> + if (ret_len != sizeof(*header)) {
> + printf("SPL: Failed to read image header\n");
> + err = -EIO;
> goto out_err;
> + }
>
> if (IS_ENABLED(CONFIG_SPL_LOAD_FIT) &&
> image_get_magic(header) == FDT_MAGIC) {
> @@ -82,8 +133,15 @@ int spl_mtd_load(struct spl_image_info *spl_image,
> err = spl_parse_image_header(spl_image, bootdev, header);
> if (err)
> goto out_err;
> - err = mtd_read(mtd, spl_mtd_get_uboot_offs(), spl_image->size,
> - &ret_len, (void *)(ulong)spl_image->load_addr);
> +
> + ret_len = spl_mtd_read_skip_bad(mtd, spl_mtd_get_uboot_offs(),
> + spl_image->size,
> + (void
> *)(ulong)spl_image->load_addr);
> + if (ret_len != spl_image->size) {
> + printf("SPL: Failed to read full image: %zu/%u bytes\n",
> + ret_len, spl_image->size);
> + err = -EIO;
> + }
> }
>
> out_err:
