[coreboot-gerrit] Change in coreboot[master]: mb/ocp/deltalake: Disable ISOC vi UPD to improve MLC performance

[Johnny Lin (Code Review)]

Johnny Lin has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/48738 )

Change subject: mb/ocp/deltalake: Disable ISOC vi UPD to improve MLC performance
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mb/ocp/deltalake: Disable ISOC vi UPD to improve MLC performance

UEFI disables ISOC, after disabling it MLC (memory latency checker)
can have the same performance as UEFI.

Tested=On OCP Delta Lake, mlc performance is improved and on par
with UEFI BIOS.

Change-Id: I08c22ee001b601e607452b3f23fad969ecb484b4
Signed-off-by: Johnny Lin 
---
M src/mainboard/ocp/deltalake/romstage.c
1 file changed, 1 insertion(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/38/48738/1

diff --git a/src/mainboard/ocp/deltalake/romstage.c b/src/mainboard/ocp/deltalake/romstage.c
index f0cdd3d..9d83d1c 100644
--- a/src/mainboard/ocp/deltalake/romstage.c
+++ b/src/mainboard/ocp/deltalake/romstage.c
@@ -75,6 +75,7 @@
    	printk(BIOS_DEBUG, "Setting MemRefreshWatermark %d from VPD\n", val);
    	mupd->FspmConfig.UnusedUpdSpace0[0] = val;
    }
+	mupd->FspmConfig.isocEn = 0;
 }

/* Update bifurcation settings according to different Configs */