Change in coreboot[master]: vc/mediatek/mt8195: Optimize DRAM init time by limiting frequency count

[Hung-Te Lin (Code Review)]

Hung-Te Lin has submitted this change. ( https://review.coreboot.org/c/coreboot/+/56849 )

Change subject: vc/mediatek/mt8195: Optimize DRAM init time by limiting frequency count
......................................................................

vc/mediatek/mt8195: Optimize DRAM init time by limiting frequency count

Support the config MEDIATEK_DRAM_DVFS_LIMIT_FREQ_CNT to limit DRAM
frequency counts to reduce DRAM initialization time by about 100ms.

BUG=b:195274787

Signed-off-by: Ryan Chuang 
Change-Id: Ibcb9a50c24f428358ef682b64946d4c91ebd81d2
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56849
Tested-by: build bot (Jenkins) 
Reviewed-by: Rex-BC Chen 
Reviewed-by: Yu-Ping Wu 
---
M src/vendorcode/mediatek/mt8195/dramc/dramc_pi_main.c
1 file changed, 3 insertions(+), 0 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Yu-Ping Wu: Looks good to me, approved
  Rex-BC Chen: Looks good to me, but someone else must approve

diff --git a/src/vendorcode/mediatek/mt8195/dramc/dramc_pi_main.c b/src/vendorcode/mediatek/mt8195/dramc/dramc_pi_main.c
index b5de592..b5b9ae1 100644
--- a/src/vendorcode/mediatek/mt8195/dramc/dramc_pi_main.c
+++ b/src/vendorcode/mediatek/mt8195/dramc/dramc_pi_main.c
@@ -1882,6 +1882,9 @@
     ett_fix_freq = 1; /* only 1600 & 4266 */
 #endif

+    if (CONFIG(MEDIATEK_DRAM_DVFS_LIMIT_FREQ_CNT))
+        ett_fix_freq = 0x1; // 4266, 1600
+
     if (ett_fix_freq != 0xff)
         gAndroid_DVFS_en = FALSE;