New patch to review for coreboot: 60a3cdc baytrail: mrc_cache: check region erased before erasing

[Aaron Durbin]

Aaron Durbin ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/5043

-gerrit

commit 60a3cdc69519eda0216b905f5764876081de888c
Author: Aaron Durbin 
Date:   Mon Jan 13 11:34:51 2014 -0600

baytrail: mrc_cache: check region erased before erasing

On a firmware update the MRC cache is destroyed. On the
    subsequent boot the MRC region was attempted to be erased
    even if it was already erased. This led to spi part taking
    longer than it should have for an unnecessary erase
    operation. Therefore, check that the region is erased
    before issuing the erease command.

BUG=chrome-os-partner:24916
    BRANCH=baytrail
    TEST=Booted after chromeos-firmeareupdate. Noted no
         error messages in this path.

Change-Id: I6fadeb6bc5fc178abb0a7e3f0898855e481add2e
    Signed-off-by: Aaron Durbin 
    Reviewed-on: https://chromium-review.googlesource.com/182153
    Reviewed-by: Duncan Laurie 
---
 src/soc/intel/baytrail/mrc_cache.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/soc/intel/baytrail/mrc_cache.c b/src/soc/intel/baytrail/mrc_cache.c
index 0ba1408..9f7676b 100644
--- a/src/soc/intel/baytrail/mrc_cache.c
+++ b/src/soc/intel/baytrail/mrc_cache.c
@@ -279,9 +279,12 @@ static void update_mrc_cache(void *unused)
    next_slot = mrc_cache_next_slot(&region, current_saved);

if (!mrc_slot_valid(&region, next_slot, current_boot)) {
-		if (nvm_erase(region.base, region.size) < 0) {
-			printk(BIOS_DEBUG, "Could not erase MRC region.\n");
-			return;
+		printk(BIOS_DEBUG, "Slot @ %p is invalid.\n", next_slot);
+		if (!nvm_is_erased(region.base, region.size)) {
+			if (nvm_erase(region.base, region.size) < 0) {
+				printk(BIOS_DEBUG, "Failure erasing region.\n");
+				return;
+			}
    	}
    	next_slot = region.base;
    }