[coreboot-gerrit] Change in coreboot[master]: mrc_cache: Remove unnecessary data checksum calculation

[Shelley Chen (Code Review)]

Shelley Chen has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/46515 )

Change subject: mrc_cache: Remove unnecessary data checksum calculation
......................................................................

mrc_cache: Remove unnecessary data checksum calculation

When MRC_SAVE_HASH_IN_TPM is selected, we can just use the TPM hash to
verify the MRC_CACHE data.  Thus, we don't need to calculate the
checksum anymore in this case.

BUG=b:150502246
BRANCH=None
TEST=make sure memory training still works on nami

Change-Id: I1db4469da49755805b541f50c7ef2f9cdb749425
Signed-off-by: Shelley Chen 
---
M src/drivers/mrc_cache/mrc_cache.c
1 file changed, 10 insertions(+), 9 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/15/46515/1

diff --git a/src/drivers/mrc_cache/mrc_cache.c b/src/drivers/mrc_cache/mrc_cache.c
index 8124b24..068ce9e 100644
--- a/src/drivers/mrc_cache/mrc_cache.c
+++ b/src/drivers/mrc_cache/mrc_cache.c
@@ -194,18 +194,19 @@
    if (md->data_size != data_size)
    	return -1;

-	checksum = compute_ip_checksum(data, data_size);
+	if (hash_idx && CONFIG(MRC_SAVE_HASH_IN_TPM)) {
+		if (!mrc_cache_verify_hash(hash_idx, data, data_size))
+			return -1;
+	} else {
+		checksum = compute_ip_checksum(data, data_size);

-	if (md->data_checksum != checksum) {
-		printk(BIOS_ERR, "MRC: data checksum mismatch: %x vs %x\n",
-			md->data_checksum, checksum);
-		return -1;
+		if (md->data_checksum != checksum) {
+			printk(BIOS_ERR, "MRC: data checksum mismatch: %x vs %x\n",
+			       md->data_checksum, checksum);
+			return -1;
+		}
    }

-	if (hash_idx && CONFIG(MRC_SAVE_HASH_IN_TPM) &&
-	    !mrc_cache_verify_hash(hash_idx, data, data_size))
-		return -1;
-
    return 0;
 }