[coreboot-gerrit] New patch to review for coreboot: 0557680 intel/gm45: Refactor DDR3 write training

[Nico Huber]

Nico Huber ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/3255

-gerrit

commit 055768012a10ce061860fafc4b4ba21fdd527ea8
Author: Nico Huber 
Date:   Tue May 14 11:58:44 2013 +0200

intel/gm45: Refactor DDR3 write training

Split some code in individual functions. It's the refactoring part of
    a bigger change, following...

Change-Id: Id19be4588ad8984935040d9bcba4d7c5f2e1114f
    Signed-off-by: Nico Huber 
---
 .../intel/gm45/raminit_read_write_training.c       | 85 ++++++++++++++--------
 1 file changed, 54 insertions(+), 31 deletions(-)

diff --git a/src/northbridge/intel/gm45/raminit_read_write_training.c b/src/northbridge/intel/gm45/raminit_read_write_training.c
index 948956a..733b087 100644
--- a/src/northbridge/intel/gm45/raminit_read_write_training.c
+++ b/src/northbridge/intel/gm45/raminit_read_write_training.c
@@ -425,6 +425,46 @@ _bad_timing_out:

return ret;
 }
+static void write_training_find_lower(const int ch, const int group,
+				      const address_bunch_t *const addresses,
+				      const u32 masks[][2], const int memclk1067,
+				      write_timing_t *const lower)
+{
+	program_write_timing(ch, group, lower, memclk1067);
+	/* Coarse search for good t. */
+	while (!write_training_test(addresses, masks[group])) {
+		++lower->t;
+		program_write_timing(ch, group, lower, memclk1067);
+	}
+	/* Fine search for good p. */
+	--lower->t;
+	program_write_timing(ch, group, lower, memclk1067);
+	while (!write_training_test(addresses, masks[group])) {
+		++lower->p;
+		program_write_timing(ch, group, lower, memclk1067);
+	}
+}
+static void write_training_find_upper(const int ch, const int group,
+				      const address_bunch_t *const addresses,
+				      const u32 masks[][2], const int memclk1067,
+				      write_timing_t *const upper)
+{
+	program_write_timing(ch, group, upper, memclk1067);
+	if (!write_training_test(addresses, masks[group]))
+		die("Write training failed; limits too narrow.\n");
+	/* Coarse search for good t. */
+	while (write_training_test(addresses, masks[group])) {
+		++upper->t;
+		program_write_timing(ch, group, upper, memclk1067);
+	}
+	/* Fine search for good p. */
+	--upper->t;
+	program_write_timing(ch, group, upper, memclk1067);
+	while (write_training_test(addresses, masks[group])) {
+		++upper->p;
+		program_write_timing(ch, group, upper, memclk1067);
+	}
+}
 static void write_training_per_group(const int ch, const int group,
    			     const address_bunch_t *const addresses,
    			     const u32 masks[][2], const int memclk1067)
@@ -433,46 +473,29 @@ static void write_training_per_group(const int ch, const int group,
    write_timing_t lower = { 0, 0, t_bound, 0 },
    	       upper = { 0, 0, t_bound, 0 };

-	/* Search lower bound. */
+	/*** Search lower bound. ***/
+
+	/* Start at -1f from current values. */
    const u32 reg = MCHBAR32(CxWRTy_MCHBAR(ch, group));
    lower.t =  (reg >> 12) & 0xf;
    lower.p =  (reg >>  8) & 0x7;
    lower.f = ((reg >>  2) & 0x3) - 1;
-	program_write_timing(ch, group, &lower, memclk1067);
-	/* Coarse search for good t. */
-	while (!write_training_test(addresses, masks[group])) {
-		++lower.t;
-		program_write_timing(ch, group, &lower, memclk1067);
-	}
-	/* Fine search for good p. */
-	--lower.t;
-	program_write_timing(ch, group, &lower, memclk1067);
-	while (!write_training_test(addresses, masks[group])) {
-		++lower.p;
-		program_write_timing(ch, group, &lower, memclk1067);
-	}

-	/* Search upper bound. */
+	write_training_find_lower(ch, group, addresses,
+				  masks, memclk1067, &lower);
+
+	/*** Search upper bound. ***/
+
+	/* Start at lower + 3t. */
    upper.t = lower.t + 3;
    upper.p = lower.p;
    upper.f = lower.f;
-	program_write_timing(ch, group, &upper, memclk1067);
-	if (!write_training_test(addresses, masks[group]))
-		die("Write training failed; limits too narrow.\n");
-	/* Coarse search for good t. */
-	while (write_training_test(addresses, masks[group])) {
-		++upper.t;
-		program_write_timing(ch, group, &upper, memclk1067);
-	}
-	/* Fine search for good p. */
-	--upper.t;
-	program_write_timing(ch, group, &upper, memclk1067);
-	while (write_training_test(addresses, masks[group])) {
-		++upper.p;
-		program_write_timing(ch, group, &upper, memclk1067);
-	}

-	/* Calculate and program mean value. */
+	write_training_find_upper(ch, group, addresses,
+				  masks, memclk1067, &upper);
+
+	/*** Calculate and program mean value. ***/
+
    lower.t += lower.f * lower.t_bound;
    lower.p += lower.t << WRITE_TIMING_P_SHIFT;
    upper.t += upper.f * upper.t_bound;