mb/nissa/var/meliks: Support x32 memory configuration

Use GPP_E7 level to determine whether x32 memory configuration is
supported.

BUG=None
BRANCH=nissa
TEST=FW_NAME=meliks emerge-nissa coreboot

Change-Id: Iedaf3c4ff1b025a4d69eca1db32ef743066a4478
Signed-off-by: Seunghwan Kim <sh_.kim@samsung.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/86804
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Eric Lai <ericllai@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/brya/Kconfig

@@ -363,6 +363,7 @@ config BOARD_GOOGLE_MELIKS
 	select BOARD_GOOGLE_BASEBOARD_NISSA
 	select DRIVERS_I2C_DA7219
 	select DRIVERS_INTEL_MIPI_CAMERA
+	select ENFORCE_MEM_CHANNEL_DISABLE
 	select SOC_INTEL_TWINLAKE
 
 config BOARD_GOOGLE_MITHRAX

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

@@ -22,6 +22,8 @@ static const struct pad_config override_gpio_table[] = {
 	/* D8  : SD_CLKREQ_ODL ==> NC */
 	PAD_NC(GPP_D8, NONE),
 
+	/* E7 : NC ==> GPP_E7_STRAP */
+	PAD_CFG_GPI_LOCK(GPP_E7, NONE, LOCK_CONFIG),
 	/* E14 : EDP_HPD ==> NC */
 	PAD_NC(GPP_E14, NONE),
 	/* E20 : HDMI_DDC_SCL ==> NC */

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

@@ -95,3 +95,17 @@ int variant_memory_sku(void)
 
 	return gpio_base2_value(spd_gpios, ARRAY_SIZE(spd_gpios));
 }
+
+uint8_t mb_get_channel_disable_mask(void)
+{
+	/*
+	 * GPP_E7 High -> One RAM Chip
+	 * GPP_E7 Low  -> Two RAM Chip
+	 */
+	if (gpio_get(GPP_E7)) {
+		/* Disable all other channels except first two on each controller */
+		return (BIT(2) | BIT(3));
+	}
+
+	return 0;
+}