Allow a slice of RAM to be mapped to a blkmap. This means that RAM can now be accessed as if it was a block device, meaning that existing filesystem drivers can now be used to access ramdisks.
Signed-off-by: Tobias Waldekranz tobias@waldekranz.com --- drivers/block/blkmap.c | 105 +++++++++++++++++++++++++++++++++++++++++ include/blkmap.h | 29 ++++++++++++ 2 files changed, 134 insertions(+)
diff --git a/drivers/block/blkmap.c b/drivers/block/blkmap.c index acfc002ceb..6d6eed889e 100644 --- a/drivers/block/blkmap.c +++ b/drivers/block/blkmap.c @@ -130,6 +130,111 @@ static int blkmap_slice_add(struct blkmap *bm, struct blkmap_slice *new) return 0; }
+/** + * struct blkmap_mem - Memory mapping + * + * @slice: Common map data + * @addr: Target memory region of this mapping + * @remapped: True if @addr is backed by a physical to virtual memory + * mapping that must be torn down at the end of this mapping's + * lifetime. + */ +struct blkmap_mem { + struct blkmap_slice slice; + void *addr; + bool remapped; +}; + +static ulong blkmap_mem_read(struct blkmap *bm, struct blkmap_slice *bms, + lbaint_t blknr, lbaint_t blkcnt, void *buffer) +{ + struct blkmap_mem *bmm = container_of(bms, struct blkmap_mem, slice); + struct blk_desc *bd = dev_get_uclass_plat(bm->blk); + char *src; + + src = bmm->addr + (blknr << bd->log2blksz); + memcpy(buffer, src, blkcnt << bd->log2blksz); + return blkcnt; +} + +static ulong blkmap_mem_write(struct blkmap *bm, struct blkmap_slice *bms, + lbaint_t blknr, lbaint_t blkcnt, + const void *buffer) +{ + struct blkmap_mem *bmm = container_of(bms, struct blkmap_mem, slice); + struct blk_desc *bd = dev_get_uclass_plat(bm->blk); + char *dst; + + dst = bmm->addr + (blknr << bd->log2blksz); + memcpy(dst, buffer, blkcnt << bd->log2blksz); + return blkcnt; +} + +static void blkmap_mem_destroy(struct blkmap *bm, struct blkmap_slice *bms) +{ + struct blkmap_mem *bmm = container_of(bms, struct blkmap_mem, slice); + + if (bmm->remapped) + unmap_sysmem(bmm->addr); +} + +int __blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt, + void *addr, bool remapped) +{ + struct blkmap *bm = dev_get_plat(dev); + struct blkmap_mem *bmm; + int err; + + bmm = malloc(sizeof(*bmm)); + if (!bmm) + return -ENOMEM; + + *bmm = (struct blkmap_mem) { + .slice = { + .blknr = blknr, + .blkcnt = blkcnt, + + .read = blkmap_mem_read, + .write = blkmap_mem_write, + .destroy = blkmap_mem_destroy, + }, + + .addr = addr, + .remapped = remapped, + }; + + err = blkmap_slice_add(bm, &bmm->slice); + if (err) + free(bmm); + + return err; +} + +int blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt, + void *addr) +{ + return __blkmap_map_mem(dev, blknr, blkcnt, addr, false); +} + +int blkmap_map_pmem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt, + phys_addr_t paddr) +{ + struct blkmap *bm = dev_get_plat(dev); + struct blk_desc *bd = dev_get_uclass_plat(bm->blk); + void *addr; + int err; + + addr = map_sysmem(paddr, blkcnt << bd->log2blksz); + if (!addr) + return -ENOMEM; + + err = __blkmap_map_mem(dev, blknr, blkcnt, addr, true); + if (err) + unmap_sysmem(addr); + + return err; +} + static ulong blkmap_blk_read_slice(struct blkmap *bm, struct blkmap_slice *bms, lbaint_t blknr, lbaint_t blkcnt, void *buffer) diff --git a/include/blkmap.h b/include/blkmap.h index 3c7e36efab..74baeb19f8 100644 --- a/include/blkmap.h +++ b/include/blkmap.h @@ -7,6 +7,35 @@ #ifndef _BLKMAP_H #define _BLKMAP_H
+/** + * blkmap_map_mem() - Map region of memory + * + * @dev: Blkmap to create the mapping on + * @blknr: Start block number of the mapping + * @blkcnt: Number of blocks to map + * @addr: The target memory address of the mapping + * Returns: 0 on success, negative error code on failure + */ +int blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt, + void *addr); + +/** + * blkmap_map_pmem() - Map region of physical memory + * + * Ensures that a valid physical to virtual memory mapping for the + * requested region is valid for the lifetime of the mapping, on + * architectures that require it (sandbox). + * + * @dev: Blkmap to create the mapping on + * @blknr: Start block number of the mapping + * @blkcnt: Number of blocks to map + * @paddr: The target physical memory address of the mapping + * Returns: 0 on success, negative error code on failure + */ +int blkmap_map_pmem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt, + phys_addr_t paddr); + + /** * blkmap_from_label() - Find blkmap from label *