[PATCH 2/2] env: mmc : align erase address and size on erase_grp_size

[Patrick Delaunay]

On eMMC device, the erase_grp_size > 1 so the address and size for the
erase block command in env/mmc.c can be unaligned on erase group size and
some strange trace occurs and the result is not guarantee by MMC devices.

The SD-Card behavior doesn't change as erase_grp_size = 1 for SD-Card.

For example, on eMMC present on STM32MP15C-EV1 and before the patch:

  STM32MP> env erase

  Erasing Environment on MMC...

  Caution! Your devices Erase group is 0x400
  The erase range would be change to 0x2000~0x27ff

  16 blocks erased: OK

  Caution! Your devices Erase group is 0x400
  The erase range would be change to 0x2000~0x23ff

  16 blocks erased: OK
  OK

After this patch:
  STM32MP> env erase
  Erasing Environment on MMC...
  1024 blocks erased at 0x2000: OK
  1024 blocks erased at 0x2000: OK
  OK

Here the 2 copies of U-Boot environment are in the same devices Erase
group: it is erased twice.

Signed-off-by: Patrick Delaunay <patrick.delaunay at foss.st.com>
---

 env/mmc.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/env/mmc.c b/env/mmc.c
index 465b104559..0c498d9a46 100644
--- a/env/mmc.c
+++ b/env/mmc.c
@@ -257,12 +257,15 @@ static inline int erase_env(struct mmc *mmc, unsigned long size,
 {
 	uint blk_start, blk_cnt, n;
 	struct blk_desc *desc = mmc_get_blk_desc(mmc);
+	u32 erase_size;
 
-	blk_start	= ALIGN(offset, mmc->write_bl_len) / mmc->write_bl_len;
-	blk_cnt		= ALIGN(size, mmc->write_bl_len) / mmc->write_bl_len;
+	erase_size = mmc->erase_grp_size * desc->blksz;
+	blk_start = ALIGN_DOWN(offset, erase_size) / desc->blksz;
+	blk_cnt = ALIGN(size, erase_size) / desc->blksz;
 
 	n = blk_derase(desc, blk_start, blk_cnt);
-	printf("%d blocks erased: %s\n", n, (n == blk_cnt) ? "OK" : "ERROR");
+	printf("%d blocks erased at 0x%x: %s\n", n, blk_start,
+	       (n == blk_cnt) ? "OK" : "ERROR");
 
 	return (n == blk_cnt) ? 0 : 1;
 }
@@ -286,6 +289,7 @@ static int env_mmc_erase(void)
 		goto fini;
 	}
 
+	printf("\n");
 	ret = erase_env(mmc, CONFIG_ENV_SIZE, offset);
 
 #ifdef CONFIG_ENV_OFFSET_REDUND
-- 
2.25.1