3 files changed, 100 insertions, 0 deletions
diff --git a/src/mainboard/google/skyrim/Kconfig b/src/mainboard/google/skyrim/Kconfig
index f44937be57..1eb6926826 100644
--- a/src/mainboard/google/skyrim/Kconfig
+++ b/src/mainboard/google/skyrim/Kconfig
@@ -126,6 +126,7 @@ config VARIANT_DIR
 config USE_VARIANT_DXIO_DESCRIPTOR
 	bool
 	default y if BOARD_GOOGLE_WINTERHOLD
+	default y if BOARD_GOOGLE_MARKARTH
 	default n
 	help
 	  Enable this to allow a variant to override the dxio descriptor values
diff --git a/src/mainboard/google/skyrim/variants/markarth/Makefile.inc b/src/mainboard/google/skyrim/variants/markarth/Makefile.inc
index 83f770047c..f9c705a4a6 100644
--- a/src/mainboard/google/skyrim/variants/markarth/Makefile.inc
+++ b/src/mainboard/google/skyrim/variants/markarth/Makefile.inc
@@ -1,4 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 
 subdirs-y += ./memory
+romstage-y += port_descriptors.c
 ramstage-y += gpio.c
+ramstage-y += port_descriptors.c
diff --git a/src/mainboard/google/skyrim/variants/markarth/port_descriptors.c b/src/mainboard/google/skyrim/variants/markarth/port_descriptors.c
new file mode 100644
index 0000000000..37edb0261a
--- /dev/null
+++ b/src/mainboard/google/skyrim/variants/markarth/port_descriptors.c
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <baseboard/variants.h>
+#include <console/console.h>
+#include <gpio.h>
+#include <soc/platform_descriptors.h>
+#include <types.h>
+
+static const fsp_dxio_descriptor emmc_dxio_descriptors[] = {
+	{
+		/* WLAN */
+		.engine_type = PCIE_ENGINE,
+		.port_present = true,
+		.start_logical_lane = 0,
+		.end_logical_lane = 0,
+		.device_number = PCI_SLOT(WLAN_DEVFN),
+		.function_number = PCI_FUNC(WLAN_DEVFN),
+		.link_speed_capability = GEN3,
+		.turn_off_unused_lanes = true,
+		.link_aspm = ASPM_L1,
+		.link_aspm_L1_1 = true,
+		.link_aspm_L1_2 = true,
+		.clk_req = CLK_REQ2,
+	},
+	{
+		/* eMMC */
+		.engine_type = PCIE_ENGINE,
+		.port_present = true,
+		.start_logical_lane = 1,
+		.end_logical_lane = 1,
+		.device_number = PCI_SLOT(SD_DEVFN),
+		.function_number = PCI_FUNC(SD_DEVFN),
+		.link_speed_capability = GEN3,
+		.turn_off_unused_lanes = true,
+		.link_aspm = ASPM_L1,
+		.link_aspm_L1_1 = true,
+		.link_aspm_L1_2 = true,
+		.gpio_group_id = GPIO_27,
+		.clk_req = CLK_REQ1,
+	},
+};
+
+static const fsp_dxio_descriptor nvme_dxio_descriptors[] = {
+	{
+		/* WLAN */
+		.engine_type = PCIE_ENGINE,
+		.port_present = true,
+		.start_logical_lane = 0,
+		.end_logical_lane = 0,
+		.device_number = PCI_SLOT(WLAN_DEVFN),
+		.function_number = PCI_FUNC(WLAN_DEVFN),
+		.link_speed_capability = GEN3,
+		.turn_off_unused_lanes = true,
+		.link_aspm = ASPM_L1,
+		.link_aspm_L1_1 = true,
+		.link_aspm_L1_2 = true,
+		.clk_req = CLK_REQ2,
+	},
+	{
+		/* SSD */
+		.engine_type = PCIE_ENGINE,
+		.port_present = true,
+		.start_logical_lane = 2,
+		.end_logical_lane = 3,
+		.device_number = PCI_SLOT(NVME_DEVFN),
+		.function_number = PCI_FUNC(NVME_DEVFN),
+		.link_speed_capability = GEN3,
+		.turn_off_unused_lanes = true,
+		.link_aspm = ASPM_L1,
+		.link_aspm_L1_1 = true,
+		.link_aspm_L1_2 = true,
+		.gpio_group_id = GPIO_6,
+		.clk_req = CLK_REQ0,
+	},
+};
+
+#define NVME_CLKREQ_GPIO 92
+void variant_get_dxio_descriptor(const fsp_dxio_descriptor **dxio_descs, size_t *dxio_num)
+{
+	/*
+	 * We can determine if a device is populated based on the state of the clkreq
+	 * signal. If the device is present, the clkreq is held low by the device. If
+	 * no device is present, clkreq is pulled high by an external pull-up.
+	 *
+	 * This allows checking the state of the NVMe device clkreq signal and enabling
+	 * either eMMC or NVMe based on that.
+	 */
+	if (gpio_get(NVME_CLKREQ_GPIO)) {
+		printk(BIOS_DEBUG, "Enabling eMMC.\n");
+		*dxio_num = ARRAY_SIZE(emmc_dxio_descriptors);
+		*dxio_descs = emmc_dxio_descriptors;
+	} else {
+		printk(BIOS_DEBUG, "Enabling NVMe.\n");
+		*dxio_num = ARRAY_SIZE(nvme_dxio_descriptors);
+		*dxio_descs = nvme_dxio_descriptors;
+	}
+}