From 6822a647b94cb05869231251e5a29f9742bb3ce2 Mon Sep 17 00:00:00 2001
From: Joe Hershberger <joe.hershberger@ni.com>
Date: Fri, 17 Aug 2012 15:36:40 -0500
Subject: [PATCH] cfi: Check for blank before erase
Added an optional check in the CFI driver to evaluate if the sector is
already blank before issuing an erase command. Improves erase time by
over a factor of 10 if already blank.
Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Stefan Roese <sr@denx.de>
---
drivers/mtd/cfi_flash.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index f0f301a460..97a4fd7cfa 100644
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -1078,6 +1078,32 @@ int flash_erase (flash_info_t * info, int s_first, int s_last)
for (sect = s_first; sect <= s_last; sect++) {
if (info->protect[sect] == 0) { /* not protected */
+#ifdef CONFIG_SYS_FLASH_CHECK_BLANK_BEFORE_ERASE
+ int k;
+ int size;
+ int erased;
+ u32 *flash;
+
+ /*
+ * Check if whole sector is erased
+ */
+ size = flash_sector_size(info, sect);
+ erased = 1;
+ flash = (u32 *)info->start[sect];
+ /* divide by 4 for longword access */
+ size = size >> 2;
+ for (k = 0; k < size; k++) {
+ if (flash_read32(flash++) != 0xffffffff) {
+ erased = 0;
+ break;
+ }
+ }
+ if (erased) {
+ if (flash_verbose)
+ putc(',');
+ continue;
+ }
+#endif
switch (info->vendor) {
case CFI_CMDSET_INTEL_PROG_REGIONS:
case CFI_CMDSET_INTEL_STANDARD:
--
2.39.5