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nb/amd/mct_ddr3: Use antiphase to better center DQS window 

The BKDG recommends the use of an antiphase window detection
algorithm to ensure that the DQS data eye is properly centered.

TEST: Booted both with DIMMs known to move the data eye into the
prior clock phase and DIMMs known to keep the data eye in the
current clock phase.

Change-Id: I1d85fddd45197ca82dcaa46fe863e64589712d1f
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: https://review.coreboot.org/12059
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <edward.ocallaghan@koparo.com>
Reviewed-by: Martin Roth <martinroth@google.com>
This commit is contained in:
Timothy Pearson 2015-08-27 15:10:19 -05:00 committed by Martin Roth
parent 323c7db204
commit 01b9f8e4c2
1 changed files with 40 additions and 17 deletions
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57
src/northbridge/amd/amdmct/mct_ddr3/mctdqs_d.c
View File

@ -1300,7 +1300,7 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
uint16_t current_read_dqs_delay[MAX_BYTE_LANES];
uint16_t current_write_dqs_delay[MAX_BYTE_LANES];
uint8_t passing_dqs_delay_found[MAX_BYTE_LANES];
uint8_t dqs_results_array[2][(lane_end - lane_start)][32][32]; /* [rank][lane][write step][read step] */
uint8_t dqs_results_array[2][(lane_end - lane_start)][32][48]; /* [rank][lane][write step][read step + 16] */
uint8_t last_pos = 0;
uint8_t cur_count = 0;
@ -1400,16 +1400,24 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
*/
dword = Get_NB32_DCT(dev, dct, 0x268) & 0x3ffff;
if (dword & (0x3 << (lane * 2)))
dqs_results_array[Receiver & 0x1][lane - lane_start][current_write_data_delay[lane] - initial_write_dqs_delay[lane]][current_read_dqs_delay[lane] >> 1] = 0; /* Fail */
dqs_results_array[Receiver & 0x1][lane - lane_start][current_write_data_delay[lane] - initial_write_dqs_delay[lane]][(current_read_dqs_delay[lane] >> 1) + 16] = 0; /* Fail */
else
dqs_results_array[Receiver & 0x1][lane - lane_start][current_write_data_delay[lane] - initial_write_dqs_delay[lane]][current_read_dqs_delay[lane] >> 1] = 1; /* Pass */
dqs_results_array[Receiver & 0x1][lane - lane_start][current_write_data_delay[lane] - initial_write_dqs_delay[lane]][(current_read_dqs_delay[lane] >> 1) + 16] = 1; /* Pass */
if ((current_read_dqs_delay[lane] >> 1) >= (32 - 16)) {
/* Check antiphase results */
dword = Get_NB32_DCT(dev, dct, 0x26c) & 0x3ffff;
if (dword & (0x3 << (lane * 2)))
dqs_results_array[Receiver & 0x1][lane - lane_start][current_write_data_delay[lane] - initial_write_dqs_delay[lane]][16 - (32 - (current_read_dqs_delay[lane] >> 1))] = 0; /* Fail */
else
dqs_results_array[Receiver & 0x1][lane - lane_start][current_write_data_delay[lane] - initial_write_dqs_delay[lane]][16 - (32 - (current_read_dqs_delay[lane] >> 1))] = 1; /* Pass */
}
}
}
if (dual_rank && (Receiver & 0x1)) {
/* Overlay the previous rank test results with the current rank */
for (write_iter = 0; write_iter < 32; write_iter++) {
for (read_iter = 0; read_iter < 32; read_iter++) {
for (read_iter = 0; read_iter < 48; read_iter++) {
if ((dqs_results_array[0][lane - lane_start][write_iter][read_iter])
&& (dqs_results_array[1][lane - lane_start][write_iter][read_iter]))
dqs_results_array[1][lane - lane_start][write_iter][read_iter] = 1;
@ -1427,8 +1435,8 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
best_pos = 0;
best_count = 0;
for (write_iter = 0; write_iter < 32; write_iter++) {
for (read_iter = 0; read_iter < 32; read_iter++) {
if ((dqs_results_array[Receiver & 0x1][lane - lane_start][write_iter][read_iter]) && (read_iter < 31)) {
for (read_iter = 0; read_iter < 48; read_iter++) {
if ((dqs_results_array[Receiver & 0x1][lane - lane_start][write_iter][read_iter]) && (read_iter < 47)) {
/* Pass */
cur_count++;
} else {
@ -1438,18 +1446,28 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
best_pos = last_pos;
}
cur_count = 0;
last_pos = read_iter;
last_pos = read_iter + 1;
}
}
last_pos = 0;
}
if (best_count > 2) {
uint16_t region_center = (best_pos + (best_count / 2));
if (region_center < 16) {
printk(BIOS_WARNING, "TrainDQSRdWrPos: negative DQS recovery delay detected!"
" Attempting to continue but your system may be unstable...\n");
region_center = 0;
} else {
region_center -= 16;
}
/* Restore current settings of other (previously trained) lanes to the active array */
memcpy(current_read_dqs_delay, initial_read_dqs_delay, sizeof(current_read_dqs_delay));
/* Program the Read DQS Timing Control register with the center of the passing window */
current_read_dqs_delay[lane] = ((best_pos << 1) + ((best_count << 1) / 2));
current_read_dqs_delay[lane] = region_center << 1;
passing_dqs_delay_found[lane] = 1;
/* Commit the current Read DQS Timing Control settings to the hardware registers */
@ -1460,6 +1478,7 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
print_debug_dqs("\t\t\t\tTrainDQSRdWrPos: 142 largest read passing region ", best_count, 4);
print_debug_dqs("\t\t\t\tTrainDQSRdWrPos: 143 largest read passing region start ", best_pos, 4);
print_debug_dqs("\t\t\t\tTrainDQSRdWrPos: 144 largest read passing region center (raw hardware value) ", region_center, 4);
} else {
/* Reprogram the Read DQS Timing Control register with the original settings */
write_dqs_read_data_timing_registers(initial_read_dqs_delay, dev, dct, dimm, index_reg);
@ -1472,7 +1491,7 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
cur_count = 0;
best_pos = 0;
best_count = 0;
for (read_iter = 0; read_iter < 32; read_iter++) {
for (read_iter = 0; read_iter < 48; read_iter++) {
for (write_iter = 0; write_iter < 32; write_iter++) {
if ((dqs_results_array[Receiver & 0x1][lane - lane_start][write_iter][read_iter]) && (write_iter < 31)) {
/* Pass */
@ -1484,7 +1503,7 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
best_pos = last_pos;
}
cur_count = 0;
last_pos = write_iter;
last_pos = write_iter + 1;
}
}
last_pos = 0;
@ -1507,8 +1526,8 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
/* Save the final Write Data Timing settings for later use */
pDCTstat->CH_D_DIR_B_DQS[dct][Receiver >> 1][DQS_WRITEDIR][lane] = current_write_dqs_delay[lane];
print_debug_dqs("\t\t\t\tTrainDQSRdWrPos: 144 largest write passing region ", best_count, 4);
print_debug_dqs("\t\t\t\tTrainDQSRdWrPos: 145 largest write passing region start ", best_pos, 4);
print_debug_dqs("\t\t\t\tTrainDQSRdWrPos: 145 largest write passing region ", best_count, 4);
print_debug_dqs("\t\t\t\tTrainDQSRdWrPos: 146 largest write passing region start ", best_pos, 4);
} else {
/* 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);
@ -1517,12 +1536,16 @@ static uint8_t TrainDQSRdWrPos_D_Fam15(struct MCTStatStruc *pMCTstat,
#ifdef PRINT_PASS_FAIL_BITMAPS
for (lane = lane_start; lane < lane_end; lane++) {
for (read_iter = 0; read_iter < 32; read_iter++) {
for (write_iter = 0; write_iter < 32; write_iter++) {
if (dqs_results_array[Receiver & 0x1][lane - lane_start][write_iter][read_iter])
for (write_iter = 0; write_iter < 32; write_iter++) {
for (read_iter = 0; read_iter < 48; read_iter++) {
if (dqs_results_array[Receiver & 0x1][lane - lane_start][write_iter][read_iter]) {
printk(BIOS_DEBUG, "+");
else
printk(BIOS_DEBUG, ".");
} else {
if (read_iter < 16)
printk(BIOS_DEBUG, "°");
else
printk(BIOS_DEBUG, ".");
}
}
printk(BIOS_DEBUG, "\n");
}