[U-Boot] [PATCH v2] dfu: mmc: add support for in-partition offset

[Marek Szyprowski]

Add possibility to define a part of partition as a separate DFU entity.
This allows to have more than one items on the given partition.

The real use case for this option is TM2 board. It can use u-boot stored
as Linux kernel on the defined partition (as RAW data) and load the real
kernel from the same partition, but stored under the certain offset.

Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
Acked-by: Lukasz Majewski <lukma at denx.de>
---
Changelog:
- fixed minor coding style issue
- made it a stand alone patch, independent from the main patchset:
https://patchwork.ozlabs.org/cover/994309/
---
 drivers/dfu/dfu_mmc.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/dfu/dfu_mmc.c b/drivers/dfu/dfu_mmc.c
index 403fd5351d..5b551f6ae1 100644
--- a/drivers/dfu/dfu_mmc.c
+++ b/drivers/dfu/dfu_mmc.c
@@ -352,6 +352,7 @@ int dfu_fill_entity_mmc(struct dfu_entity *dfu, char *devstr, char *s)
 		struct blk_desc *blk_dev = mmc_get_blk_desc(mmc);
 		int mmcdev = second_arg;
 		int mmcpart = third_arg;
+		int offset = 0;
 
 		if (part_get_info(blk_dev, mmcpart, &partinfo) != 0) {
 			pr_err("Couldn't find part #%d on mmc device #%d\n",
@@ -359,9 +360,17 @@ int dfu_fill_entity_mmc(struct dfu_entity *dfu, char *devstr, char *s)
 			return -ENODEV;
 		}
 
+		/*
+		 * Check for an extra entry at dfu_alt_info env variable
+		 * specifying the mmc HW defined partition number
+		 */
+		if (s)
+			if (!strcmp(strsep(&s, " "), "offset"))
+				offset = simple_strtoul(s, NULL, 0);
+
 		dfu->layout			= DFU_RAW_ADDR;
-		dfu->data.mmc.lba_start		= partinfo.start;
-		dfu->data.mmc.lba_size		= partinfo.size;
+		dfu->data.mmc.lba_start		= partinfo.start + offset;
+		dfu->data.mmc.lba_size		= partinfo.size-offset;
 		dfu->data.mmc.lba_blk_size	= partinfo.blksz;
 	} else if (!strcmp(entity_type, "fat")) {
 		dfu->layout = DFU_FS_FAT;
-- 
2.17.1