Merge branch '2023-04-05-blkmap-composable-virtual-block-devices'

To quote the author:
Block maps are a way of looking at various sources of data through the
lens of a regular block device. It lets you treat devices that are not
block devices, like RAM, as if they were. It also lets you export a
slice of an existing block device, which does not have to correspond to
a partition boundary, as a new block device.

This is primarily useful because U-Boot's filesystem drivers only
operate on block devices, so a block map lets you access filesystems
wherever they might be located.

The implementation is loosely modeled on Linux's "Device Mapper"
subsystem, see the kernel documentation [1] for more information.

The primary use-cases are to access filesystem images stored in RAM, and
within FIT images stored on disk. See doc/usage/blkmap.rst for more
details.

The architecture is pluggable, so adding other types of mappings should
be quite easy.

[1]: https://docs.kernel.org/admin-guide/device-mapper/index.html

1 files changed, 11 insertions, 4 deletions

diff --git a/cmd/blk_common.c b/cmd/blk_common.c
index 75a072caf5..9f9d4327a9 100644
--- a/cmd/blk_common.c
+++ b/cmd/blk_common.c
@@ -11,6 +11,7 @@
 #include <common.h>
 #include <blk.h>
 #include <command.h>
+#include <mapmem.h>
 
 int blk_common_cmd(int argc, char *const argv[], enum uclass_id uclass_id,
 		   int *cur_devnump)
@@ -63,31 +64,37 @@ int blk_common_cmd(int argc, char *const argv[], enum uclass_id uclass_id,
 
 	default: /* at least 4 args */
 		if (strcmp(argv[1], "read") == 0) {
-			ulong addr = hextoul(argv[2], NULL);
+			phys_addr_t paddr = hextoul(argv[2], NULL);
 			lbaint_t blk = hextoul(argv[3], NULL);
 			ulong cnt = hextoul(argv[4], NULL);
+			void *vaddr;
 			ulong n;
 
 			printf("\n%s read: device %d block # "LBAFU", count %lu ... ",
 			       if_name, *cur_devnump, blk, cnt);
 
+			vaddr = map_sysmem(paddr, 512 * cnt);
 			n = blk_read_devnum(uclass_id, *cur_devnump, blk, cnt,
-					    (ulong *)addr);
+					    vaddr);
+			unmap_sysmem(vaddr);
 
 			printf("%ld blocks read: %s\n", n,
 			       n == cnt ? "OK" : "ERROR");
 			return n == cnt ? 0 : 1;
 		} else if (strcmp(argv[1], "write") == 0) {
-			ulong addr = hextoul(argv[2], NULL);
+			phys_addr_t paddr = hextoul(argv[2], NULL);
 			lbaint_t blk = hextoul(argv[3], NULL);
 			ulong cnt = hextoul(argv[4], NULL);
+			void *vaddr;
 			ulong n;
 
 			printf("\n%s write: device %d block # "LBAFU", count %lu ... ",
 			       if_name, *cur_devnump, blk, cnt);
 
+			vaddr = map_sysmem(paddr, 512 * cnt);
 			n = blk_write_devnum(uclass_id, *cur_devnump, blk, cnt,
-					     (ulong *)addr);
+					     vaddr);
+			unmap_sysmem(vaddr);
 
 			printf("%ld blocks written: %s\n", n,
 			       n == cnt ? "OK" : "ERROR");