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bios/sdram: iterate multiple time for write leveling and add vote to eliminate transcients

This commit is contained in:
Florent Kermarrec 2018-11-05 18:44:28 +01:00
parent 09f962fdc4
commit fc0d5c3963
1 changed files with 17 additions and 6 deletions
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23
litex/soc/software/bios/sdram.c
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@ -229,7 +229,7 @@ void sdrwloff(void)
int write_level(void)
{
int i, j;
int i, j, k;
int dq_address;
unsigned char dq;
@ -269,11 +269,22 @@ int write_level(void)
#endif
/* scan taps */
for(j=0;j<err_ddrphy_wdly;j++) {
ddrphy_wlevel_strobe_write(1);
cdelay(10);
dq = MMPTR(dq_address);
printf("%d", dq != 0);
taps_scan[j] = (dq != 0);
int zero_count = 0;
int one_count = 0;
for (k=0; k<128; k++) {
ddrphy_wlevel_strobe_write(1);
cdelay(10);
dq = MMPTR(dq_address);
if (dq != 0)
one_count++;
else
zero_count++;
}
if (one_count > zero_count)
taps_scan[j] = 1;
else
taps_scan[j] = 0;
printf("%d", taps_scan[j]);
ddrphy_wdly_dq_inc_write(1);
ddrphy_wdly_dqs_inc_write(1);
cdelay(10);