nb/intel/sandybridge/raminit: Find CMD rate per channel

No need to find the same CMD rate for all channels.
Allow different CMD rates for every channel.

Tested on Lenovo T420 with different modules on each channel.
No regressions found.

Change-Id: I7036275ae89335dd3549ec392fa64824355b3cbf
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/17472
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

1 files changed, 53 insertions, 53 deletions

diff --git a/src/northbridge/intel/sandybridge/raminit.c b/src/northbridge/intel/sandybridge/raminit.c
index a07e8a126d..33c88f3f07 100644
--- a/src/northbridge/intel/sandybridge/raminit.c
+++ b/src/northbridge/intel/sandybridge/raminit.c
@@ -2971,23 +2971,24 @@ static void reprogram_320c(ramctr_timing * ctrl)
 
 #define MIN_C320C_LEN 13
 
-static int try_cmd_stretch(ramctr_timing *ctrl, int cmd_stretch)
+static int try_cmd_stretch(ramctr_timing *ctrl, int channel, int cmd_stretch)
 {
 	struct ram_rank_timings saved_timings[NUM_CHANNELS][NUM_SLOTRANKS];
-	int channel, slotrank;
+	int slotrank;
 	int c320c;
 	int stat[NUM_SLOTRANKS][256];
+	int delta = 0;
 
-	FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
-		saved_timings[channel][slotrank] = ctrl->timings[channel][slotrank];
-	}
+	printram("Trying cmd_stretch %d on channel %d\n", cmd_stretch, channel);
 
-	FOR_ALL_POPULATED_CHANNELS {
-		ctrl->cmd_stretch[channel] = cmd_stretch;
+	FOR_ALL_POPULATED_RANKS {
+		saved_timings[channel][slotrank] =
+			ctrl->timings[channel][slotrank];
 	}
 
-	FOR_ALL_POPULATED_CHANNELS
-	    MCHBAR32(0x4004 + 0x400 * channel) =
+	ctrl->cmd_stretch[channel] = cmd_stretch;
+
+	MCHBAR32(0x4004 + 0x400 * channel) =
 		ctrl->tRRD
 		| (ctrl->tRTP << 4)
 		| (ctrl->tCKE << 8)
@@ -2996,50 +2997,46 @@ static int try_cmd_stretch(ramctr_timing *ctrl, int cmd_stretch)
 		| (ctrl->tWR << 24)
 		| (ctrl->cmd_stretch[channel] << 30);
 
+	if (ctrl->cmd_stretch[channel] == 2)
+		delta = 2;
+	else if (ctrl->cmd_stretch[channel] == 0)
+		delta = 4;
 
-	FOR_ALL_CHANNELS {
-		int delta = 0;
-		if (ctrl->cmd_stretch[channel] == 2)
-			delta = 2;
-		else if (ctrl->cmd_stretch[channel] == 0)
-			delta = 4;
+	FOR_ALL_POPULATED_RANKS {
+		ctrl->timings[channel][slotrank].val_4024 -= delta;
+	}
 
+	for (c320c = -127; c320c <= 127; c320c++) {
+		FOR_ALL_POPULATED_RANKS {
+			ctrl->timings[channel][slotrank].val_320c = c320c;
+		}
+		program_timings(ctrl, channel);
+		reprogram_320c(ctrl);
 		FOR_ALL_POPULATED_RANKS {
-			ctrl->timings[channel][slotrank].val_4024 -= delta;
+			stat[slotrank][c320c + 127] =
+				test_320c(ctrl, channel, slotrank);
+			printram("3stat: %d, %d, %d: %x\n",
+				   channel, slotrank, c320c,
+				   stat[slotrank][c320c + 127]);
 		}
 	}
-
-	FOR_ALL_POPULATED_CHANNELS {
-		for (c320c = -127; c320c <= 127; c320c++) {
-			FOR_ALL_POPULATED_RANKS {
-				ctrl->timings[channel][slotrank].val_320c = c320c;
-			}
-			program_timings(ctrl, channel);
-			reprogram_320c(ctrl);
+	FOR_ALL_POPULATED_RANKS {
+		struct run rn =
+			get_longest_zero_run(stat[slotrank], 255);
+		ctrl->timings[channel][slotrank].val_320c =
+			rn.middle - 127;
+		printram("3val: %d, %d: %d\n", channel,
+			   slotrank,
+			   ctrl->timings[channel][slotrank].val_320c);
+		if (rn.all || rn.length < MIN_C320C_LEN) {
 			FOR_ALL_POPULATED_RANKS {
-				stat[slotrank][c320c + 127] =
-				    test_320c(ctrl, channel, slotrank);
-				printram("3stat: %d, %d, %d: %x\n",
-				       channel, slotrank, c320c,
-				       stat[slotrank][c320c + 127]);
-			}
-		}
-		FOR_ALL_POPULATED_RANKS {
-			struct run rn =
-			    get_longest_zero_run(stat[slotrank], 255);
-			ctrl->timings[channel][slotrank].val_320c =
-			    rn.middle - 127;
-			printram("3val: %d, %d: %d\n", channel,
-			       slotrank,
-			       ctrl->timings[channel][slotrank].val_320c);
-			if (rn.all || rn.length < MIN_C320C_LEN) {
-				FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
-					ctrl->timings[channel][slotrank] = saved_timings[channel][slotrank];
-				}
-				return MAKE_ERR;
+				ctrl->timings[channel][slotrank] =
+					saved_timings[channel][slotrank];
 			}
+			return MAKE_ERR;
 		}
 	}
+
 	return 0;
 }
 
@@ -3056,19 +3053,22 @@ static int command_training(ramctr_timing *ctrl)
 		write32(DEFAULT_MCHBAR + 0x4288 + 0x400 * channel, 0x1f);
 	}
 
-	/* try command rate 1T and 2T */
-	err = try_cmd_stretch(ctrl, 0);
-	if (err) {
-		err = try_cmd_stretch(ctrl, 2);
+	FOR_ALL_POPULATED_CHANNELS {
+		/* try command rate 1T and 2T */
+		err = try_cmd_stretch(ctrl, channel, 0);
 		if (err) {
-			printk(BIOS_EMERG, "c320c discovery failed\n");
-			return 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);
 	}
 
-	FOR_ALL_POPULATED_CHANNELS {
+	FOR_ALL_POPULATED_CHANNELS
 		program_timings(ctrl, channel);
-	}
 
 	reprogram_320c(ctrl);
 	return 0;