flash: Add optional verify-after-write feature

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_FLASH_VERIFY in your board config header.

Please note that this option is useless in nearly all cases,
since such flash programming errors usually are detected earlier
while unprotecting/erasing/programming. Please only enable
this option if you really know what you are doing.

Signed-off-by: Stefan Roese <sr@denx.de>

diff --git a/README b/README
index 0bc0af570062451f195a7e01dbb387048d1c134b..862bb3e6c12d43d3c93eead4d772dd1f8d9eca68 100644 (file)
--- a/README
+++ b/README
@@ -3248,6 +3248,15 @@ Configuration Settings:
                digits and dots.  Recommended value: 45 (9..1) for 80
                column displays, 15 (3..1) for 40 column displays.
 
+- CONFIG_FLASH_VERIFY
+               If defined, the content of the flash (destination) is compared
+               against the source after the write operation. An error message
+               will be printed when the contents are not identical.
+               Please note that this option is useless in nearly all cases,
+               since such flash programming errors usually are detected earlier
+               while unprotecting/erasing/programming. Please only enable
+               this option if you really know what you are doing.
+
 - CONFIG_SYS_RX_ETH_BUFFER:
                Defines the number of Ethernet receive buffers. On some
                Ethernet controllers it is recommended to set this value

diff --git a/common/flash.c b/common/flash.c
index 8244ba2ddde65b029cb5b5f8af9f8236129ddcb7..0c57a3fcdde9b6bc777e6501721e1b0d4bc1f5c1 100644 (file)
--- 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_FLASH_VERIFY)
+       if (memcmp(src_orig, addr_orig, cnt_orig)) {
+               printf("\nVerify failed!\n");
+               return ERR_PROG_ERROR;
+       }
+#endif /* CONFIG_SYS_FLASH_VERIFY_AFTER_WRITE */
+
        return (ERR_OK);
 #endif /* CONFIG_SPD823TS */
 }