mt8173: dram: Add more sample points to improve dram timing margin

BRANCH=none
BUG=chrome-os-partner:52959
TEST=verified on elm-EVT SKU1/SKU2, Oak-rev5 2GB/4GB models.

Change-Id: I228c629d9a3d6cd8fc5c4e8ba24cc52d5283b4e6
Signed-off-by: Martin Roth <martinroth@chromium.org>
Original-Commit-Id: 3c19e7d
Original-Change-Id: I22356aa8d196c4c126742cfc7e85cc693acd9b39
Original-Signed-off-by: PH Hsu <ph.hsu@mediatek.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/347716
Original-Commit-Ready: Yidi Lin <yidi.lin@mediatek.com>
Original-Tested-by: Yidi Lin <yidi.lin@mediatek.com>
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/15115
Tested-by: build bot (Jenkins)
Reviewed-by: Furquan Shaikh <furquan@google.com>

2 files changed, 25 insertions, 22 deletions

diff --git a/src/soc/mediatek/mt8173/dramc_pi_basic_api.c b/src/soc/mediatek/mt8173/dramc_pi_basic_api.c
index ac28373a39..e3efec9cf8 100644
--- a/src/soc/mediatek/mt8173/dramc_pi_basic_api.c
+++ b/src/soc/mediatek/mt8173/dramc_pi_basic_api.c
@@ -539,8 +539,11 @@ void dramc_init(u32 channel, const struct mt8173_sdram_params *sdram_params)
 	write32(&ch[channel].ao_regs->conf1,
 		sdram_params->ac_timing.conf1);
 
+	/* bit 17,18 would bypass some dummy path */
 	write32(&ch[channel].ddrphy_regs->dqsgctl, 0x1 << 31 |
 						   0x1 << 30 |
+						   0x1 << 17 |
+						   0x1 << 18 |
 						   0x1 << 4  |
 						   0x1 << 0);
 
@@ -691,6 +694,9 @@ void dramc_phy_reset(u32 channel)
 void dramc_runtime_config(u32 channel,
 			  const struct mt8173_sdram_params *sdram_params)
 {
+	setbits_le32(&ch[channel].ddrphy_regs->dqsgctl,
+		BIT(17)|BIT(18));
+
 	/* enable hw gating */
 	setbits_le32(&ch[channel].ao_regs->dqscal0,
 		     1 << DQSCAL0_STBCALEN_SHIFT);
diff --git a/src/soc/mediatek/mt8173/dramc_pi_calibration_api.c b/src/soc/mediatek/mt8173/dramc_pi_calibration_api.c
index 1237b2e0ba..fa69f2e4c2 100644
--- a/src/soc/mediatek/mt8173/dramc_pi_calibration_api.c
+++ b/src/soc/mediatek/mt8173/dramc_pi_calibration_api.c
@@ -13,9 +13,9 @@
  * GNU General Public License for more details.
  */
 
-#include <delay.h>
-#include <boardid.h>
 #include <arch/io.h>
+#include <assert.h>
+#include <delay.h>
 #include <stdlib.h>
 #include <soc/addressmap.h>
 #include <soc/dramc_common.h>
@@ -305,32 +305,28 @@ static int dqs_gw_test(u32 channel)
 static u8 dqs_gw_fine_tune_calib(u32 channel, u8 fine_val)
 {
 	u8 i, opt_fine_val;
-	s8 gw_ret[3], delta[3] = {0, -16, 16};
+	s8 delta[7] = {-48, -32, -16, 0, 16, 32, 48};
+	int matches = 0, sum = 0;
 
-	for (i = 0; i < 3; i++) {
-		/* adjust gw fine tune */
+	/* fine tune range from 0 to 127 */
+	fine_val = min(max(fine_val, 0 - delta[0]), 127 - delta[6]);
+
+	/* test gw fine tune */
+	for (i = 0; i < ARRAY_SIZE(delta); i++) {
 		opt_fine_val = fine_val + delta[i];
 		set_gw_fine_factor(channel, opt_fine_val, 0);
-		/* get gw test result */
-		gw_ret[i] = dqs_gw_test(channel);
+		if (dqs_gw_test(channel)) {
+			matches++;
+			sum += delta[i];
+		}
 	}
 
-	/* start fine tune adjustment from default fine value */
-	opt_fine_val = fine_val;
-
-	if (gw_ret[0] && gw_ret[1] && gw_ret[2]) {
-		opt_fine_val += ((delta[0] + delta[1] + delta[2]) / 3);
-	}
-	else if (gw_ret[0] && gw_ret[1]) {
-		opt_fine_val += ((delta[0] + delta[1]) / 2);
-	}
-	else if (gw_ret[0] && gw_ret[2]) {
-		opt_fine_val += ((delta[0] + delta[2]) / 2);
-	}
-	else {  /* abnormal test result, set to default fine tune value */
-		printk(BIOS_ERR, "[GW] ERROR, No found fine tune!!!\n");
+	if (matches == 0) {
+		die("[GW] ERROR, Fine-Tuning failed.\n");
 	}
 
+	opt_fine_val = fine_val + (sum / matches);
+
 	return opt_fine_val;
 }
 
@@ -737,7 +733,8 @@ u8 rx_datlat_cal(u32 channel, u8 rank,
 
 	if (err[0]) {
 		/* dle test error */
-		printk(BIOS_ERR, "[DLE] calibration ERROR!\n");
+		printk(BIOS_ERR, "[DLE] CH:%d calibration ERROR CMP_ERR =%xh,\n",
+			channel, err[0]);
 	} else {
 		/* judge dle test result */
 		for (i = 0; i < DLE_TEST_NUM; i++) {