mb/google/nissa/var/rull: Support x32 memory configuration

Use GPP_E19 level to determine whether x32 memory configuration is
supported.

BUG=b:480003949
TEST=emerge-nissa coreboot chromeos-bootimage

Change-Id: I68d9060686f6b48c2fd7a296cd78346233265e24
Signed-off-by: Qinghong Zeng <zengqinghong@huaqin.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/91003
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Eric Lai <ericllai@google.com>

src/mainboard/google/brya/Kconfig

@@ -605,6 +605,7 @@ config BOARD_GOOGLE_RULL
 	select CHROMEOS_WIFI_SAR if CHROMEOS
 	select DRIVERS_GENERIC_BAYHUB_LV2
 	select DRIVERS_GENERIC_GPIO_KEYS
+	select ENFORCE_MEM_CHANNEL_DISABLE
 	select MAINBOARD_HAS_GOOGLE_STRAUSS_KEYBOARD
 	select SOC_INTEL_TWINLAKE
 

src/mainboard/google/brya/variants/rull/Makefile.mk

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 bootblock-y += gpio.c
 
+romstage-y += memory.c
 romstage-y += gpio.c
 
 ramstage-y += gpio.c

src/mainboard/google/brya/variants/rull/gpio.c

@@ -90,6 +90,9 @@ static const struct pad_config override_gpio_table[] = {
 	/* R7 : DMIC_DATA_1A ==> DMIC_WCAM_DATA */
 	PAD_CFG_NF(GPP_R7, NONE, DEEP, NF3),
 
+	/* E19 : DDP1_CTRLDATA ==> GPP_E19_STRAP */
+	PAD_CFG_GPI_LOCK(GPP_E19, DN_20K, LOCK_CONFIG),
+
 	/* Configure the virtual CNVi Bluetooth I2S GPIO pads */
 	/* BT_I2S_BCLK */
 	PAD_CFG_NF(GPP_VGPIO_30, NONE, DEEP, NF3),
@@ -138,6 +141,8 @@ static const struct pad_config early_gpio_table[] = {
 	PAD_CFG_NF(GPP_H11, NONE, DEEP, NF2),
     /* H20 : IMGCLKOUT1 ==> WLAN_PERST_L */
 	PAD_CFG_GPO(GPP_H20, 0, DEEP),
+	/* E19 : DDP1_CTRLDATA ==> GPP_E19_STRAP */
+	PAD_CFG_GPI(GPP_E19, DN_20K, DEEP),
 };
 
 static const struct pad_config romstage_gpio_table[] = {

src/mainboard/google/brya/variants/rull/memory.c

@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <baseboard/gpio.h>
+#include <baseboard/variants.h>
+#include <gpio.h>
+#include <soc/romstage.h>
+
+uint8_t mb_get_channel_disable_mask(void)
+{
+	/*
+	 * GPP_E19 High -> One RAM Chip
+	 * GPP_E19 Low  -> Two RAM Chip
+	 * Disable all other channels except first two on each controller
+	 */
+	if (gpio_get(GPP_E19))
+		return (BIT(2) | BIT(3));
+
+	return 0;
+}