From 0814b122281d2e4f10e40c2a8d5085f810e2730e Mon Sep 17 00:00:00 2001
From: Marshall Dawson <marshalldawson3rd@gmail.com>
Date: Wed, 10 Jan 2018 11:35:24 -0700
Subject: amd/stoneyridge: Keep SPI flash cacheable during POST

A side effect of using the common MTRR assignment code is the flash
device loses its WP setting and is no longer cacheable.  After MTRR
setup, reenable the setting for the duration of POST.

TEST=Run on Kahlee and inspect MTRRs prior to AmdInitLate()
BUG=b:70536683

Change-Id: Ib4924e96e2876e1e92121bb52d1931ead723d730
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/23205
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Richard Spiegel <richard.spiegel@silverbackltd.com>
---
 src/soc/amd/stoneyridge/cpu.c | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'src/soc/amd/stoneyridge/cpu.c')

diff --git a/src/soc/amd/stoneyridge/cpu.c b/src/soc/amd/stoneyridge/cpu.c
index 0490137988..86429e207e 100644
--- a/src/soc/amd/stoneyridge/cpu.c
+++ b/src/soc/amd/stoneyridge/cpu.c
@@ -24,6 +24,7 @@
 #include <soc/cpu.h>
 #include <soc/northbridge.h>
 #include <soc/smi.h>
+#include <soc/iomap.h>
 #include <console/console.h>
 
 /*
@@ -47,6 +48,10 @@ static struct smm_relocation_attrs relo_attrs;
 static void pre_mp_init(void)
 {
 	x86_setup_mtrrs_with_detect();
+
+	/* The flash is now no longer cacheable. Reset to WP for performance. */
+	mtrr_use_temp_range(FLASH_BASE_ADDR, CONFIG_ROM_SIZE, MTRR_TYPE_WRPROT);
+
 	x86_mtrr_check();
 }
 
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