Change in coreboot[master]: nb/intel/sandybridge/raminit: Set REFIx9 according to spec

[Patrick Rudolph (Code Review)]

Patrick Rudolph has uploaded this change for review. ( https://review.coreboot.org/22259

Change subject: nb/intel/sandybridge/raminit: Set REFIx9 according to spec
......................................................................

nb/intel/sandybridge/raminit: Set REFIx9 according to spec

Set tREFIx9 to 8.9*tREFI/1024 as suggested in
xeon-e3-1200v3-vol-2-datasheet.pdf chapter 4.2.15 or
2nd-gen-core-family-mobile-vol-2-datasheet chapter 2.14.1.

Use the minimum value of REFI*8.9 and tRASmax as suggested by
3rd-gen-core-desktop-vol-2-datasheet.pdf chapter 2.13.9.

Change-Id: Ifd32a70f28aa75418030b0e4d1fc7d539a315f83
Signed-off-by: Patrick Rudolph 
---
M src/northbridge/intel/sandybridge/raminit_common.c
1 file changed, 12 insertions(+), 10 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/59/22259/1

diff --git a/src/northbridge/intel/sandybridge/raminit_common.c b/src/northbridge/intel/sandybridge/raminit_common.c
index eaef5f7..88357f6 100644
--- a/src/northbridge/intel/sandybridge/raminit_common.c
+++ b/src/northbridge/intel/sandybridge/raminit_common.c
@@ -263,16 +263,18 @@

dram_odt_stretch(ctrl, channel);

-		// REFI
-		reg = 0;
-		val32 = ctrl->tREFI;
-		reg = (reg & ~0xffff) | val32;
-		val32 = ctrl->tRFC;
-		reg = (reg & ~0x1ff0000) | (val32 << 16);
-		val32 = (u32) (ctrl->tREFI * 9) / 1024;
-		reg = (reg & ~0xfe000000) | (val32 << 25);
-		printram("REFI [%x] = %x\n", 0x400 * channel + 0x4298,
-		       reg);
+		/*
+		 * TC—Refresh timing parameters
+		 * The tREFIx9 field should be programmed to minimum of
+		 * 8.9*tREFI (to allow for possible delays from ZQ or
+		 * isoc) and tRASmax (70us) divided by 1024.
+		 */
+		val32 = MIN((ctrl->tREFI * 89) / 10, (70000 << 8) / ctrl->tCK);
+
+		reg = ((ctrl->tREFI & 0xffff) << 0) |
+			((ctrl->tRFC & 0x1ff) << 16) |
+			(((val32 / 1024) & 0x7f) << 25);
+		printram("REFI [%x] = %x\n", 0x400 * channel + 0x4298, reg);
    	MCHBAR32(0x400 * channel + 0x4298) = reg;

MCHBAR32(0x400 * channel + 0x4294) |= 0xff;