mb/google/hatch: Use MEM_CH_SEL to indicate single_channel sku

MEM_CH_SEL is used to indicate whether we are on a single or dual
channel device, where MEM_CH_SEL = 1 for single channel skus and
MEM_CH_SEL = 0 for dual channel skus.  Initialize single_channel field
(from GPP_F2), which will in turn initialize MemorySpdPtr pointers in
cannonlake soc code.  In the first build, we did not use GPP_F2, so we
need to add an internal pulldown as those early devices were all dual
channel devices.

BUG=b:123062346, b:122959294
BRANCH=None
TEST=Boot into current boards and ensure that we have 2 channels as expected
     Also, verify that GPP_F2 is set to 0.

Change-Id: I89d022793580be603a93d0b177d73ce968529b5c
Signed-off-by: Shelley Chen <shchen@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31358
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

1 files changed, 19 insertions, 2 deletions

diff --git a/src/mainboard/google/hatch/variants/baseboard/memory.c b/src/mainboard/google/hatch/variants/baseboard/memory.c
index 80f3ba4260..6ca98e4c7f 100644
--- a/src/mainboard/google/hatch/variants/baseboard/memory.c
+++ b/src/mainboard/google/hatch/variants/baseboard/memory.c
@@ -17,6 +17,7 @@
 #include <baseboard/gpio.h>
 #include <gpio.h>
 #include <soc/cnl_memcfg_init.h>
+#include <string.h>
 
 static const struct cnl_mb_cfg baseboard_memcfg = {
 	/*
@@ -42,9 +43,25 @@ static const struct cnl_mb_cfg baseboard_memcfg = {
 	.ect = 1,
 };
 
-const struct cnl_mb_cfg *__weak variant_memory_params(void)
+void __weak variant_memory_params(struct cnl_mb_cfg *bcfg)
 {
-	return &baseboard_memcfg;
+	memcpy(bcfg, &baseboard_memcfg, sizeof(baseboard_memcfg));
+	/*
+	 * GPP_F2 is the MEM_CH_SEL gpio, which is set to 1 for single
+	 * channel skus and 0 for dual channel skus.
+	 */
+	if (gpio_get(GPP_F2) == 1) {
+		/*
+		 * Single channel config: for Hatch, Channel 0 is
+		 * always populated.
+		 */
+		bcfg->channel_empty[0] = 0;
+		bcfg->channel_empty[1] = 1;
+	} else {
+		/* Dual channel config: both channels populated. */
+		bcfg->channel_empty[0] = 0;
+		bcfg->channel_empty[1] = 0;
+	}
 }
 
 int __weak variant_memory_sku(void)