[U-Boot] [PATCH] flash: Add optional verify-after-write feature

[Stefan Roese <sr@denx.de>]

Sometimes it might make sense to verify the written data to NOR flash.
This patch adds this feature. To enable this verify-after-write, you
need to define CONFIG_SYS_FLASH_VERIFY_AFTER_WRITE in your board
config header.

Signed-off-by: Stefan Roese <sr@denx.de>
---
 common/flash.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/common/flash.c b/common/flash.c
index 8244ba2..3ae3c9a 100644
--- a/common/flash.c
+++ b/common/flash.c
@@ -149,6 +149,9 @@ flash_write (char *src, ulong addr, ulong cnt)
 	flash_info_t *info_first = addr2info (addr);
 	flash_info_t *info_last  = addr2info (end );
 	flash_info_t *info;
+	__maybe_unused char *src_orig = src;
+	__maybe_unused char *addr_orig = (char *)addr;
+	__maybe_unused ulong cnt_orig = cnt;
 
 	if (cnt == 0) {
 		return (ERR_OK);
@@ -185,6 +188,14 @@ flash_write (char *src, ulong addr, ulong cnt)
 		addr += len;
 		src  += len;
 	}
+
+#if defined(CONFIG_SYS_FLASH_VERIFY_AFTER_WRITE)
+	if (memcmp(src_orig, addr_orig, cnt_orig)) {
+		printf("\nVerify-after-write failed!\n");
+		return ERR_PROG_ERROR;
+	}
+#endif /* CONFIG_SYS_FLASH_VERIFY_AFTER_WRITE */
+
 	return (ERR_OK);
 #endif /* CONFIG_SPD823TS */
 }
-- 
1.8.2