[coreboot-gerrit] Change in coreboot[master]: nb/intel/sandybridge: Clarify IOSAV_DATA_CTL_ch usage

[Angel Pons (Code Review)]

Angel Pons has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/47484 )

Change subject: nb/intel/sandybridge: Clarify IOSAV_DATA_CTL_ch usage
......................................................................

nb/intel/sandybridge: Clarify IOSAV_DATA_CTL_ch usage

It is usually written to right after programming a pattern, because its
lower byte contains the number of cachelines of the programmed pattern.
The other cases merely reset the WDB data write and compare pointers.

Change-Id: I97196d404bf70542db28499e0d2e24b7cdab07b6
Signed-off-by: Angel Pons 
---
M src/northbridge/intel/sandybridge/raminit_common.c
1 file changed, 14 insertions(+), 10 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/84/47484/1

diff --git a/src/northbridge/intel/sandybridge/raminit_common.c b/src/northbridge/intel/sandybridge/raminit_common.c
index 3527c8e..3ab8df2 100644
--- a/src/northbridge/intel/sandybridge/raminit_common.c
+++ b/src/northbridge/intel/sandybridge/raminit_common.c
@@ -1953,6 +1953,12 @@
    return ret;
 }

+/* Each cacheline is 64 bits long */
+static void program_wdb_pattern_length(int channel, const unsigned int num_cachelines)
+{
+	MCHBAR8(IOSAV_DATA_CTL_ch(channel)) = num_cachelines / 8 - 1;
+}
+
 static void fill_pattern0(ramctr_timing *ctrl, int channel, u32 a, u32 b)
 {
    unsigned int j;
@@ -1962,6 +1968,8 @@
    	write32((void *)(0x04000000 + channel_offset + 4 * j), j & 2 ? b : a);

sfence();
+
+	program_wdb_pattern_length(channel, 8);
 }

static int num_of_channels(const ramctr_timing *ctrl)
@@ -1985,6 +1993,8 @@
    	write32((void *)(0x04000000 + channel_offset + channel_step + j * 4), 0);

sfence();
+
+	program_wdb_pattern_length(channel, 16);
 }

static void precharge(ramctr_timing *ctrl)
@@ -2370,10 +2380,10 @@
    MCHBAR32(GDCRTRAININGMOD) = 0x200;
    FOR_ALL_POPULATED_CHANNELS {
    	fill_pattern1(ctrl, channel);
-		MCHBAR32(IOSAV_DATA_CTL_ch(channel)) = 1;
    }
    FOR_ALL_POPULATED_CHANNELS FOR_ALL_POPULATED_RANKS {

+		/* Reset read and write WDB pointers */
    	MCHBAR32(IOSAV_DATA_CTL_ch(channel)) = 0x10001;

wait_for_iosav(channel);
@@ -2728,7 +2738,6 @@

FOR_ALL_POPULATED_CHANNELS {
    	fill_pattern0(ctrl, channel, 0xaaaaaaaa, 0x55555555);
-		MCHBAR32(IOSAV_DATA_CTL_ch(channel)) = 0;
    }

FOR_ALL_CHANNELS FOR_ALL_POPULATED_RANKS {
@@ -2770,6 +2779,7 @@
    		MCHBAR32(IOSAV_By_ERROR_COUNT(lane)) = 0;
    	}

+		/* Reset read WDB pointer */
    	MCHBAR32(IOSAV_DATA_CTL_ch(channel)) = 0x1f;

wait_for_iosav(channel);
@@ -2937,6 +2947,8 @@
    	}
    	sfence();
    }
+
+	program_wdb_pattern_length(channel, 256);
 }

static void reprogram_320c(ramctr_timing *ctrl)
@@ -3104,7 +3116,6 @@

FOR_ALL_POPULATED_CHANNELS {
    	fill_pattern5(ctrl, channel, 0);
-		MCHBAR32(IOSAV_DATA_CTL_ch(channel)) = 0x1f;
    }

FOR_ALL_POPULATED_CHANNELS {
@@ -3312,7 +3323,6 @@

FOR_ALL_POPULATED_CHANNELS {
    	fill_pattern0(ctrl, channel, 0, 0);
-		MCHBAR32(IOSAV_DATA_CTL_ch(channel)) = 0;
    	FOR_ALL_LANES {
    		MCHBAR32(IOSAV_By_BW_SERROR_C_ch(channel, lane));
    	}
@@ -3563,7 +3573,6 @@
    	}

fill_pattern0(ctrl, channel, 0, 0xffffffff);
-		MCHBAR32(IOSAV_DATA_CTL_ch(channel)) = 0;
    }

/*
@@ -3631,7 +3640,6 @@

for (pat = 0; pat < NUM_PATTERNS; pat++) {
    		fill_pattern5(ctrl, channel, pat);
-			MCHBAR32(IOSAV_DATA_CTL_ch(channel)) = 0x1f;
    		printram("using pattern %d\n", pat);

for (edge = 0; edge <= MAX_EDGE_TIMING; edge++) {
@@ -4000,7 +4008,6 @@
    				stats[MAX_TIMC] = 1;

fill_pattern5(ctrl, channel, pat);
-					MCHBAR32(IOSAV_DATA_CTL_ch(channel)) = 0x1f;

for (timC = 0; timC < MAX_TIMC; timC++) {
    					FOR_ALL_LANES {
@@ -4130,8 +4137,6 @@
    	}
    FOR_ALL_POPULATED_CHANNELS {
    	fill_pattern0(ctrl, channel, 0x12345678, 0x98765432);
-
-		MCHBAR32(IOSAV_DATA_CTL_ch(channel)) = 0;
    }

for (slotrank = 0; slotrank < 4; slotrank++)
@@ -4272,7 +4277,6 @@
    FOR_ALL_POPULATED_CHANNELS {
    	wait_for_iosav(channel);
    	fill_pattern0(ctrl, channel, 0, 0);
-		MCHBAR32(IOSAV_DATA_CTL_ch(channel)) = 0;
    }

/*