[coreboot-gerrit] Patch set updated for coreboot: northbridge/amd/amdmct/mct_ddr3: Fix odd rank data corruption due to incorrect DQS training

[Timothy Pearson (tpearson@raptorengineeringinc.com)]

Timothy Pearson (tpearson at raptorengineeringinc.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/12058

-gerrit

commit e1da6392d60e4735e8b972fd20e009c2686ab638
Author: Timothy Pearson <tpearson at raptorengineeringinc.com>
Date:   Thu Aug 27 13:19:34 2015 -0500

    northbridge/amd/amdmct/mct_ddr3: Fix odd rank data corruption due to incorrect DQS training
    
    Change-Id: Ibc51f5052d5189e45b3d9aa98ca8febbfe13f178
    Signed-off-by: Timothy Pearson <tpearson at raptorengineeringinc.com>
---
 src/northbridge/amd/amdmct/mct_ddr3/mctdqs_d.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/src/northbridge/amd/amdmct/mct_ddr3/mctdqs_d.c b/src/northbridge/amd/amdmct/mct_ddr3/mctdqs_d.c
index c520515..739a893 100644
--- a/src/northbridge/amd/amdmct/mct_ddr3/mctdqs_d.c
+++ b/src/northbridge/amd/amdmct/mct_ddr3/mctdqs_d.c
@@ -1324,9 +1324,9 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
 		Receiver = receiver_start;
 
 	/* There are four receiver pairs, loosely associated with chipselects.
-	 * This is essentially looping over each DIMM.
+	 * This is essentially looping over each rank within each DIMM.
 	 */
-	for (; Receiver < receiver_end; Receiver += 2) {
+	for (; Receiver < receiver_end; Receiver++) {
 		dimm = (Receiver >> 1);
 		if ((Receiver & 0x1) == 0) {
 			/* Even rank of DIMM */
@@ -1340,18 +1340,27 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
 			continue;
 		}
 
+#if DQS_TRAIN_DEBUG > 0
+		printk(BIOS_DEBUG, "TrainDQSRdWrPos: Training DQS read/write position for receiver %d (DIMM %d)\n", Receiver, dimm);
+#endif
+
 		/* Initialize variables */
 		for (lane = lane_start; lane < lane_end; lane++) {
 			passing_dqs_delay_found[lane] = 0;
 		}
-		memset(dqs_results_array, 0, sizeof(dqs_results_array));
+		if ((Receiver & 0x1) == 0) {
+			/* Even rank of DIMM */
+			memset(dqs_results_array, 0, sizeof(dqs_results_array));
+
+			/* Read initial read / write DQS delays */
+			read_dqs_write_timing_control_registers(initial_write_dqs_delay, dev, dct, dimm, index_reg);
+			read_dqs_read_data_timing_registers(initial_read_dqs_delay, dev, dct, dimm, index_reg);
 
-		/* Read initial read / write DQS delays */
-		read_dqs_write_timing_control_registers(initial_write_dqs_delay, dev, dct, dimm, index_reg);
-		read_dqs_read_data_timing_registers(initial_read_dqs_delay, dev, dct, dimm, index_reg);
+			/* Read current settings of other (previously trained) lanes */
+			read_dqs_write_data_timing_registers(initial_write_data_timing, dev, dct, dimm, index_reg);
+		}
 
-		/* Read current settings of other (previously trained) lanes */
-		read_dqs_write_data_timing_registers(initial_write_data_timing, dev, dct, dimm, index_reg);
+		/* Initialize iterators */
 		memcpy(current_write_data_delay, initial_write_data_timing, sizeof(current_write_data_delay));
 
 		for (lane = lane_start; lane < lane_end; lane++) {