Allow a slice of an existing block device to be mapped to a blkmap. This means that filesystems that are not stored at exact partition boundaries can be accessed by remapping a slice of the existing device to a blkmap device.
Signed-off-by: Tobias Waldekranz <[email protected]> --- drivers/block/blkmap.c | 71 ++++++++++++++++++++++++++++++++++++++++++ include/blkmap.h | 2 ++ 2 files changed, 73 insertions(+) diff --git a/drivers/block/blkmap.c b/drivers/block/blkmap.c index c8c2dcac11..14d2ec3f78 100644 --- a/drivers/block/blkmap.c +++ b/drivers/block/blkmap.c @@ -94,6 +94,77 @@ static int blkmap_add(struct blkmap *bm, struct blkmap_slice *new) return 0; } +struct blkmap_linear { + struct blkmap_slice slice; + + struct blk_desc *bd; + lbaint_t blknr; +}; + +static ulong blkmap_linear_read(struct blkmap *bm, struct blkmap_slice *bms, + lbaint_t blknr, lbaint_t blkcnt, void *buffer) +{ + struct blkmap_linear *bml = container_of(bms, struct blkmap_linear, slice); + + return blk_dread(bml->bd, bml->blknr + blknr, blkcnt, buffer); +} + +static ulong blkmap_linear_write(struct blkmap *bm, struct blkmap_slice *bms, + lbaint_t blknr, lbaint_t blkcnt, + const void *buffer) +{ + struct blkmap_linear *bml = container_of(bms, struct blkmap_linear, slice); + + return blk_dwrite(bml->bd, bml->blknr + blknr, blkcnt, buffer); +} + +int blkmap_map_linear(int devnum, lbaint_t blknr, lbaint_t blkcnt, + enum uclass_id lcls, int ldevnum, lbaint_t lblknr) +{ + struct blkmap_linear *linear; + struct blk_desc *bd, *lbd; + struct blkmap *bm; + int err; + + bm = blkmap_from_devnum(devnum); + if (!bm) + return -ENODEV; + + bd = dev_get_uclass_plat(bm->dev); + lbd = blk_get_devnum_by_uclass_id(lcls, ldevnum); + if (!lbd) + return -ENODEV; + + if (lbd->blksz != bd->blksz) + /* We could support block size translation, but we + * don't yet. + */ + return -EINVAL; + + linear = malloc(sizeof(*linear)); + if (!linear) + return -ENOMEM; + + *linear = (struct blkmap_linear) { + .slice = { + .blknr = blknr, + .blkcnt = blkcnt, + + .read = blkmap_linear_read, + .write = blkmap_linear_write, + }, + + .bd = lbd, + .blknr = lblknr, + }; + + err = blkmap_add(bm, &linear->slice); + if (err) + free(linear); + + return err; +} + struct blkmap_mem { struct blkmap_slice slice; void *addr; diff --git a/include/blkmap.h b/include/blkmap.h index a93611ff62..dca6e3fe6a 100644 --- a/include/blkmap.h +++ b/include/blkmap.h @@ -9,6 +9,8 @@ #include <stdbool.h> +int blkmap_map_linear(int devnum, lbaint_t blknr, lbaint_t blkcnt, + enum uclass_id lcls, int ldevnum, lbaint_t lblknr); int blkmap_map_mem(int devnum, lbaint_t blknr, lbaint_t blkcnt, void *addr); int blkmap_map_pmem(int devnum, lbaint_t blknr, lbaint_t blkcnt, phys_addr_t paddr); -- 2.34.1
