nb/intel/sandybridge: Clean up `dram_mr2` function

Constify variables, and also remove pointless and-masks on mr2reg.

Tested on Asus P8H61-M PRO, still boots.

Change-Id: I3829012ff7d41f4308ee84d6fbf3b1f2803431af
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47569
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

1 files changed, 9 insertions, 12 deletions

diff --git a/src/northbridge/intel/sandybridge/raminit_common.c b/src/northbridge/intel/sandybridge/raminit_common.c
index 453222e59d..3ed1a3a335 100644
--- a/src/northbridge/intel/sandybridge/raminit_common.c
+++ b/src/northbridge/intel/sandybridge/raminit_common.c
@@ -757,22 +757,19 @@ static void dram_mr1(ramctr_timing *ctrl, u8 rank, int channel)
 
 static void dram_mr2(ramctr_timing *ctrl, u8 rank, int channel)
 {
-	u16 pasr, cwl, mr2reg;
-	odtmap odt;
-	int srt = 0;
-
-	pasr = 0;
-	cwl = ctrl->CWL - 5;
-	odt = get_ODT(ctrl, channel);
+	const u16 pasr = 0;
+	const u16 cwl = ctrl->CWL - 5;
+	const odtmap odt = get_ODT(ctrl, channel);
 
+	int srt = 0;
 	if (IS_IVY_CPU(ctrl->cpu) && ctrl->tCK >= TCK_1066MHZ)
 		srt = ctrl->extended_temperature_range && !ctrl->auto_self_refresh;
 
-	mr2reg = 0;
-	mr2reg = (mr2reg & ~0x07) | pasr;
-	mr2reg = (mr2reg & ~0x38) | (cwl << 3);
-	mr2reg = (mr2reg & ~0x40) | (ctrl->auto_self_refresh << 6);
-	mr2reg = (mr2reg & ~0x80) | (srt << 7);
+	u16 mr2reg = 0;
+	mr2reg |= pasr;
+	mr2reg |= cwl << 3;
+	mr2reg |= ctrl->auto_self_refresh << 6;
+	mr2reg |= srt << 7;
 	mr2reg |= (odt.rttwr / 60) << 9;
 
 	write_mrreg(ctrl, channel, rank, 2, mr2reg);