nb/intel/sandybridge: Use bitfield for GDCRCMDPICODING

This register's layout makes no sense, so use bitfields for clarity.

Tested on Asus P8H61-M PRO, still boots.

Change-Id: I61efc7349badc2c3297c9b71535dceecaba509d0
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47571
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

2 files changed, 31 insertions, 7 deletions

diff --git a/src/northbridge/intel/sandybridge/raminit_common.c b/src/northbridge/intel/sandybridge/raminit_common.c
index d18e302de0..60f9e1fdd6 100644
--- a/src/northbridge/intel/sandybridge/raminit_common.c
+++ b/src/northbridge/intel/sandybridge/raminit_common.c
@@ -917,7 +917,7 @@ static const u32 lane_base[] = {
 
 void program_timings(ramctr_timing *ctrl, int channel)
 {
-	u32 reg32, reg_roundtrip_latency, reg_pi_code, reg_logic_delay, reg_io_latency;
+	u32 reg_roundtrip_latency, reg_pi_code, reg_logic_delay, reg_io_latency;
 	int lane;
 	int slotrank, slot;
 	int full_shift = 0;
@@ -950,13 +950,18 @@ void program_timings(ramctr_timing *ctrl, int channel)
 		}
 
 	/* Enable CMD XOVER */
-	reg32 = get_XOVER_CMD(ctrl->rankmap[channel]);
-	reg32 |= (pi_coding_ctrl[0] & 0x3f) <<  6;
-	reg32 |= (pi_coding_ctrl[0] & 0x40) <<  9;
-	reg32 |= (pi_coding_ctrl[1] & 0x7f) << 18;
-	reg32 |= (full_shift & 0x3f) | ((full_shift & 0x40) << 6);
+	union gdcr_cmd_pi_coding_reg cmd_pi_coding = {
+		.raw = get_XOVER_CMD(ctrl->rankmap[channel]),
+	};
+	cmd_pi_coding.cmd_pi_code = full_shift & 0x3f;
+	cmd_pi_coding.cmd_logic_delay = !!(full_shift & 0x40);
+
+	cmd_pi_coding.ctl_pi_code_d0 = pi_coding_ctrl[0] & 0x3f;
+	cmd_pi_coding.ctl_pi_code_d1 = pi_coding_ctrl[1] & 0x3f;
+	cmd_pi_coding.ctl_logic_delay_d0 = !!(pi_coding_ctrl[0] & 0x40);
+	cmd_pi_coding.ctl_logic_delay_d1 = !!(pi_coding_ctrl[1] & 0x40);
 
-	MCHBAR32(GDCRCMDPICODING_ch(channel)) = reg32;
+	MCHBAR32(GDCRCMDPICODING_ch(channel)) = cmd_pi_coding.raw;
 
 	/* Enable CLK XOVER */
 	reg_pi_code = get_XOVER_CLK(ctrl->rankmap[channel]);
diff --git a/src/northbridge/intel/sandybridge/raminit_common.h b/src/northbridge/intel/sandybridge/raminit_common.h
index 0aa687da70..798b4828e5 100644
--- a/src/northbridge/intel/sandybridge/raminit_common.h
+++ b/src/northbridge/intel/sandybridge/raminit_common.h
@@ -98,6 +98,25 @@ struct iosav_ssq {
 	} addr_update;
 };
 
+union gdcr_cmd_pi_coding_reg {
+	struct {
+		u32 cmd_pi_code         : 6; /* [ 5.. 0] */
+		u32 ctl_pi_code_d0      : 6; /* [11.. 6] */
+		u32 cmd_logic_delay     : 1; /* [12..12] */
+		u32 cmd_phase_delay     : 1; /* [13..13] */
+		u32 cmd_xover_enable    : 1; /* [14..14] */
+		u32 ctl_logic_delay_d0  : 1; /* [15..15] */
+		u32 ctl_phase_delay_d0  : 1; /* [16..16] */
+		u32 ctl_xover_enable_d0 : 1; /* [17..17] */
+		u32 ctl_pi_code_d1      : 6; /* [23..18] */
+		u32 ctl_logic_delay_d1  : 1; /* [24..24] */
+		u32 ctl_phase_delay_d1  : 1; /* [25..25] */
+		u32 ctl_xover_enable_d1 : 1; /* [26..26] */
+		u32                     : 5;
+	};
+	u32 raw;
+};
+
 union tc_dbp_reg {
 	struct {
 		u32 tRCD : 4; /* [ 3.. 0] */