New patch to review for coreboot: nb/amd/mct_ddr3: Require minumum training quality for both read and write

[Timothy Pearson]

Timothy Pearson ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/13993

-gerrit

commit 422e64eec6d7d18bb5b5f773514c0b6d0ff25ad3
Author: Timothy Pearson 
Date:   Tue Mar 8 16:44:39 2016 -0600

nb/amd/mct_ddr3: Require minumum training quality for both read and write

The existing MCT code proceeded to the next DRAM training phase if
    the minimum lane quality standard passed for either the read or
    write direction.  Ensure that both pass for a given set of delay
    values before proceeding to the next training phase.

Change-Id: I2316ca639f58a23cf64bea56290e9422e02edf1c
    Signed-off-by: Timothy Pearson 
---
 src/northbridge/amd/amdmct/mct_ddr3/mctdqs_d.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/northbridge/amd/amdmct/mct_ddr3/mctdqs_d.c b/src/northbridge/amd/amdmct/mct_ddr3/mctdqs_d.c
index 19a7acb..d2ecefa 100644
--- a/src/northbridge/amd/amdmct/mct_ddr3/mctdqs_d.c
+++ b/src/northbridge/amd/amdmct/mct_ddr3/mctdqs_d.c
@@ -1318,6 +1318,8 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
    uint8_t write_iter;
    uint8_t read_iter;
    uint8_t check_antiphase;
+	uint8_t passing_read_dqs_delay_found;
+	uint8_t passing_write_dqs_delay_found;
    uint16_t initial_write_dqs_delay[MAX_BYTE_LANES];
    uint16_t initial_read_dqs_delay[MAX_BYTE_LANES];
    uint16_t initial_write_data_timing[MAX_BYTE_LANES];
@@ -1385,6 +1387,9 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
    	memcpy(current_write_data_delay, initial_write_data_timing, sizeof(current_write_data_delay));

for (lane = lane_start; lane < lane_end; lane++) {
+			passing_read_dqs_delay_found = 0;
+			passing_write_dqs_delay_found = 0;
+
    		/* 2.10.5.8.4 (2)
    		 * For each Write Data Delay value from Write DQS Delay to Write DQS Delay + 1 UI
    		 */
@@ -1510,7 +1515,7 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,

/* Program the Read DQS Timing Control register with the center of the passing window */
    			current_read_dqs_delay[lane] = region_center << 1;
-				passing_dqs_delay_found[lane] = 1;
+				passing_read_dqs_delay_found = 1;

/* Commit the current Read DQS Timing Control settings to the hardware registers */
    			write_dqs_read_data_timing_registers(current_read_dqs_delay, dev, dct, dimm, index_reg);
@@ -1560,7 +1565,7 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
    				current_write_dqs_delay[lane] = ((best_pos + initial_write_dqs_delay[lane]) + (best_count / 3));
    			else
    				current_write_dqs_delay[lane] = ((best_pos + initial_write_dqs_delay[lane]) + (best_count / 2));
-				passing_dqs_delay_found[lane] = 1;
+				passing_write_dqs_delay_found = 1;

/* Commit the current Write DQS Timing Control settings to the hardware registers */
    			write_dqs_write_data_timing_registers(current_write_dqs_delay, dev, dct, dimm, index_reg);
@@ -1574,6 +1579,9 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
    			/* Reprogram the Write DQS Timing Control register with the original settings */
    			write_dqs_write_data_timing_registers(current_write_dqs_delay, dev, dct, dimm, index_reg);
    		}
+
+			if (passing_read_dqs_delay_found && passing_write_dqs_delay_found)
+				passing_dqs_delay_found[lane] = 1;
    	}

#ifdef PRINT_PASS_FAIL_BITMAPS