Only the SPI-NAND bind path currently creates an mtd_blk block device, so a bare NOR (parallel NOR, SPI-NOR, ...) has no block-device access at all. Bind an mtd_blk device for every non-NAND MTD master when CONFIG_MTD_BLOCK is enabled, so its partitions become reachable through the block layer (and thus by bootstd, imagemap, ...).
NAND is excluded on purpose: it needs UBI, which brings its own block device. Partitions inherit the master's block device via the "mtd" partition type, so only masters are bound. mtd_bind() keeps a pointer to the passed mtd_info pointer (SPI-NAND fills it after bind), so the generic caller provides a small heap slot that lives as long as the block device; an MTD master is never removed in practice. Signed-off-by: Daniel Golle <[email protected]> --- drivers/mtd/mtdcore.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 3bfa5aebbc6..e0d0b5ae2e9 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -494,6 +494,30 @@ int add_mtd_device(struct mtd_info *mtd) #endif mutex_unlock(&mtd_table_mutex); + + if (IS_ENABLED(CONFIG_MTD_BLOCK) && mtd->dev && + !mtd_is_partition(mtd) && !mtd_type_is_nand(mtd)) { + /* + * Expose a non-NAND MTD master (parallel NOR, SPI-NOR, ...) as + * a mtd_blk block device, so its partitions are reachable + * through the block layer (and thus by imagemap, bootstd, ...). + * NAND is excluded: it needs UBI, which brings its own block + * device. Partitions inherit the master's block device via the + * "mtd" partition type, so only masters are bound. + * + * mtd_bind() keeps a pointer to the passed mtd_info pointer, so + * it needs storage that lives as long as the block device; the + * MTD master is never removed in practice, so a small heap slot + * is fine. + */ + struct mtd_info **mtdp = kmalloc(sizeof(*mtdp), GFP_KERNEL); + + if (mtdp) { + *mtdp = mtd; + mtd_bind(mtd->dev, mtdp); + } + } + /* We _know_ we aren't being removed, because our caller is still holding us here. So none of this try_ nonsense, and no bitching about it -- 2.55.0
