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-rw-r--r--src/northbridge/intel/sandybridge/raminit_common.c39
1 files changed, 28 insertions, 11 deletions
diff --git a/src/northbridge/intel/sandybridge/raminit_common.c b/src/northbridge/intel/sandybridge/raminit_common.c
index be0589dd8b..c6ff551fbf 100644
--- a/src/northbridge/intel/sandybridge/raminit_common.c
+++ b/src/northbridge/intel/sandybridge/raminit_common.c
@@ -2342,7 +2342,6 @@ static int try_cmd_stretch(ramctr_timing *ctrl, int channel, int cmd_stretch)
int command_training(ramctr_timing *ctrl)
{
int channel;
- int err;
FOR_ALL_POPULATED_CHANNELS {
fill_pattern5(ctrl, channel, 0);
@@ -2350,17 +2349,35 @@ int command_training(ramctr_timing *ctrl)
}
FOR_ALL_POPULATED_CHANNELS {
- /* try command rate 1T and 2T */
- err = try_cmd_stretch(ctrl, channel, 0);
+ int cmdrate, err;
+
+ /*
+ * Dual DIMM per channel:
+ * Issue: While c320c discovery seems to succeed raminit
+ * will fail in write training.
+ * Workaround: Skip 1T in dual DIMM mode, that's only
+ * supported by a few DIMMs.
+ * TODO: How to detect "1T" DIMMs ?
+ *
+ * Single DIMM per channel:
+ * Try command rate 1T and 2T
+ */
+ cmdrate = ((ctrl->rankmap[channel] & 0x5) == 0x5);
+
+ for(; cmdrate < 2; cmdrate++) {
+ err = try_cmd_stretch(ctrl, channel, cmdrate << 1);
+
+ if (!err)
+ break;
+ }
+
if (err) {
- err = try_cmd_stretch(ctrl, channel, 2);
- if (err) {
- printk(BIOS_EMERG, "c320c discovery failed\n");
- return err;
- }
- printram("Using CMD rate 2T on channel %u\n", channel);
- } else
- printram("Using CMD rate 1T on channel %u\n", channel);
+ printk(BIOS_EMERG, "c320c discovery failed\n");
+ return err;
+ }
+
+ printram("Using CMD rate %uT on channel %u\n",
+ cmdrate + 1, channel);
}
FOR_ALL_POPULATED_CHANNELS