4 files changed, 158 insertions, 0 deletions
diff --git a/src/drivers/intel/usb4/retimer/Kconfig b/src/drivers/intel/usb4/retimer/Kconfig
new file mode 100644
index 0000000000..eee8fe1bed
--- /dev/null
+++ b/src/drivers/intel/usb4/retimer/Kconfig
@@ -0,0 +1,8 @@
+config DRIVERS_INTEL_USB4_RETIMER
+	bool
+	depends on HAVE_ACPI_TABLES
+	help
+	   A retimer is a device that retransmits a fresh copy of the signal it
+	   receives, by doing CDR and retransmitting the data (i.e., it is
+	   protocol-aware). If your mainboard has a USB4 retimer (usually
+	   located close to the USB4 ports), then select this driver.
diff --git a/src/drivers/intel/usb4/retimer/Makefile.inc b/src/drivers/intel/usb4/retimer/Makefile.inc
new file mode 100644
index 0000000000..bca23aa3bf
--- /dev/null
+++ b/src/drivers/intel/usb4/retimer/Makefile.inc
@@ -0,0 +1 @@
+ramstage-$(CONFIG_DRIVERS_INTEL_USB4_RETIMER) += retimer.c
diff --git a/src/drivers/intel/usb4/retimer/chip.h b/src/drivers/intel/usb4/retimer/chip.h
new file mode 100644
index 0000000000..789d824a81
--- /dev/null
+++ b/src/drivers/intel/usb4/retimer/chip.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __DRIVERS_INTEL_USB4_RETIMER_H__
+#define __DRIVERS_INTEL_USB4_RETIMER_H__
+
+#include <acpi/acpi_device.h>
+
+struct drivers_intel_usb4_retimer_config {
+	/* GPIO used to control power of retimer device. */
+	struct acpi_gpio power_gpio;
+};
+
+#endif /* __DRIVERS_INTEL_USB4_RETIMER_H__ */
diff --git a/src/drivers/intel/usb4/retimer/retimer.c b/src/drivers/intel/usb4/retimer/retimer.c
new file mode 100644
index 0000000000..be9ec35230
--- /dev/null
+++ b/src/drivers/intel/usb4/retimer/retimer.c
@@ -0,0 +1,136 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <acpi/acpigen.h>
+#include <acpi/acpi_device.h>
+#include <console/console.h>
+#include <device/device.h>
+#include <device/path.h>
+#include <gpio.h>
+#include <string.h>
+#include "chip.h"
+
+/* Unique ID for the retimer _DSM. */
+#define INTEL_USB4_RETIMER_DSM_UUID	"61788900-C470-42BB-80F0-23A313864593"
+
+/*
+ * Arg0: UUID
+ * Arg1: Revision ID (set to 1)
+ * Arg2: Function Index
+ *       0: Query command implemented
+ *       1: Query force power enable state
+ *       2: Set force power state
+ * Arg3: A package containing parameters for the function specified
+ *       by the UUID, revision ID and function index.
+ */
+
+static void usb4_retimer_cb_standard_query(void *arg)
+{
+	/*
+	 * ToInteger (Arg1, Local2)
+	 * If (Local2 == 1) {
+	 *     Return(Buffer() {0x07})
+	 * }
+	 * Return (Buffer() {0x01})
+	 */
+	acpigen_write_to_integer(ARG1_OP, LOCAL2_OP);
+
+	/* Revision 1 supports 2 Functions beyond the standard query */
+	acpigen_write_if_lequal_op_int(LOCAL2_OP, 1);
+	acpigen_write_return_singleton_buffer(0x07);
+	acpigen_pop_len(); /* If */
+
+	/* Other revisions support no additional functions */
+	acpigen_write_return_singleton_buffer(0);
+}
+
+static void usb4_retimer_cb_get_power_state(void *arg)
+{
+	struct acpi_gpio *power_gpio = arg;
+
+	/*
+	 * // Read power gpio into Local0
+	 * Store (\_SB.PCI0.GTXS (power_gpio), Local0)
+	 * Return (Local0)
+	 */
+	acpigen_get_tx_gpio(power_gpio);
+	acpigen_write_return_op(LOCAL0_OP);
+}
+
+static void usb4_retimer_cb_set_power_state(void *arg)
+{
+	struct acpi_gpio *power_gpio = arg;
+
+	/*
+	 * // Get argument for on/off from Arg3[0]
+	 * Local0 = DeRefOf (Arg3[0])
+	 */
+	acpigen_get_package_op_element(ARG3_OP, 0, LOCAL0_OP);
+
+	/*
+	 * If (Local0 == 0) {
+	 *     // Turn power off
+	 *     \_SB.PCI0.CTXS (power_gpio)
+	 * }
+	 */
+	acpigen_write_if_lequal_op_int(LOCAL0_OP, 0);
+	acpigen_disable_tx_gpio(power_gpio);
+	acpigen_pop_len(); /* If */
+
+	/*
+	 * Else {
+	 *     // Turn power on
+	 *     \_SB.PCI0.STXS (power_gpio)
+	 * }
+	 */
+	acpigen_write_else();
+	acpigen_enable_tx_gpio(power_gpio);
+	acpigen_pop_len();
+
+	/* Return (Zero) */
+	acpigen_write_return_integer(0);
+}
+
+static void (*usb4_retimer_callbacks[3])(void *) = {
+	usb4_retimer_cb_standard_query,		/* Function 0 */
+	usb4_retimer_cb_get_power_state,	/* Function 1 */
+	usb4_retimer_cb_set_power_state,	/* Function 2 */
+};
+
+static void usb4_retimer_fill_ssdt(const struct device *dev)
+{
+	const struct drivers_intel_usb4_retimer_config *config = dev->chip_info;
+	const char *scope = acpi_device_scope(dev);
+
+	if (!dev->enabled || !scope || !config)
+		return;
+
+	if (!config->power_gpio.pin_count) {
+		printk(BIOS_ERR, "%s: Power GPIO required for %s\n", __func__, dev_path(dev));
+		return;
+	}
+
+	/* Write the _DSM that toggles power with provided GPIO. */
+	acpigen_write_scope(scope);
+	acpigen_write_dsm(INTEL_USB4_RETIMER_DSM_UUID, usb4_retimer_callbacks,
+			  ARRAY_SIZE(usb4_retimer_callbacks), (void *)&config->power_gpio);
+	acpigen_pop_len(); /* Scope */
+
+	printk(BIOS_INFO, "%s: %s at %s\n", acpi_device_path(dev), dev->chip_ops->name,
+	       dev_path(dev));
+}
+
+static struct device_operations usb4_retimer_dev_ops = {
+	.read_resources	= noop_read_resources,
+	.set_resources	= noop_set_resources,
+	.acpi_fill_ssdt	= usb4_retimer_fill_ssdt,
+};
+
+static void usb4_retimer_enable(struct device *dev)
+{
+	dev->ops = &usb4_retimer_dev_ops;
+}
+
+struct chip_operations drivers_intel_usb4_retimer_ops = {
+	CHIP_NAME("Intel USB4 Retimer")
+	.enable_dev = usb4_retimer_enable
+};