1 files changed, 229 insertions, 0 deletions
diff --git a/drivers/usb/roles/intel-xhci-usb-role-switch.c b/drivers/usb/roles/intel-xhci-usb-role-switch.c
new file mode 100644
index 000000000..5c96e929a
--- /dev/null
+++ b/drivers/usb/roles/intel-xhci-usb-role-switch.c
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Intel XHCI (Cherry Trail, Broxton and others) USB OTG role switch driver
+ *
+ * Copyright (c) 2016-2017 Hans de Goede <hdegoede@redhat.com>
+ *
+ * Loosely based on android x86 kernel code which is:
+ *
+ * Copyright (C) 2014 Intel Corp.
+ *
+ * Author: Wu, Hao
+ */
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/property.h>
+#include <linux/usb/role.h>
+
+/* register definition */
+#define DUAL_ROLE_CFG0			0x68
+#define SW_VBUS_VALID			BIT(24)
+#define SW_IDPIN_EN			BIT(21)
+#define SW_IDPIN			BIT(20)
+#define SW_SWITCH_EN			BIT(16)
+
+#define DRD_CONFIG_DYNAMIC		0
+#define DRD_CONFIG_STATIC_HOST		1
+#define DRD_CONFIG_STATIC_DEVICE	2
+#define DRD_CONFIG_MASK			3
+
+#define DUAL_ROLE_CFG1			0x6c
+#define HOST_MODE			BIT(29)
+
+#define DUAL_ROLE_CFG1_POLL_TIMEOUT	1000
+
+#define DRV_NAME			"intel_xhci_usb_sw"
+
+struct intel_xhci_usb_data {
+	struct device *dev;
+	struct usb_role_switch *role_sw;
+	void __iomem *base;
+	bool enable_sw_switch;
+};
+
+static const struct software_node intel_xhci_usb_node = {
+	"intel-xhci-usb-sw",
+};
+
+static int intel_xhci_usb_set_role(struct usb_role_switch *sw,
+				   enum usb_role role)
+{
+	struct intel_xhci_usb_data *data = usb_role_switch_get_drvdata(sw);
+	unsigned long timeout;
+	acpi_status status;
+	u32 glk, val;
+	u32 drd_config = DRD_CONFIG_DYNAMIC;
+
+	/*
+	 * On many CHT devices ACPI event (_AEI) handlers read / modify /
+	 * write the cfg0 register, just like we do. Take the ACPI lock
+	 * to avoid us racing with the AML code.
+	 */
+	status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
+	if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
+		dev_err(data->dev, "Error could not acquire lock\n");
+		return -EIO;
+	}
+
+	pm_runtime_get_sync(data->dev);
+
+	/*
+	 * Set idpin value as requested.
+	 * Since some devices rely on firmware setting DRD_CONFIG and
+	 * SW_SWITCH_EN bits to be zero for role switch,
+	 * do not set these bits for those devices.
+	 */
+	val = readl(data->base + DUAL_ROLE_CFG0);
+	switch (role) {
+	case USB_ROLE_NONE:
+		val |= SW_IDPIN;
+		val &= ~SW_VBUS_VALID;
+		drd_config = DRD_CONFIG_DYNAMIC;
+		break;
+	case USB_ROLE_HOST:
+		val &= ~SW_IDPIN;
+		val &= ~SW_VBUS_VALID;
+		drd_config = DRD_CONFIG_STATIC_HOST;
+		break;
+	case USB_ROLE_DEVICE:
+		val |= SW_IDPIN;
+		val |= SW_VBUS_VALID;
+		drd_config = DRD_CONFIG_STATIC_DEVICE;
+		break;
+	}
+	val |= SW_IDPIN_EN;
+	if (data->enable_sw_switch) {
+		val &= ~DRD_CONFIG_MASK;
+		val |= SW_SWITCH_EN | drd_config;
+	}
+	writel(val, data->base + DUAL_ROLE_CFG0);
+
+	acpi_release_global_lock(glk);
+
+	/* In most case it takes about 600ms to finish mode switching */
+	timeout = jiffies + msecs_to_jiffies(DUAL_ROLE_CFG1_POLL_TIMEOUT);
+
+	/* Polling on CFG1 register to confirm mode switch.*/
+	do {
+		val = readl(data->base + DUAL_ROLE_CFG1);
+		if (!!(val & HOST_MODE) == (role == USB_ROLE_HOST)) {
+			pm_runtime_put(data->dev);
+			return 0;
+		}
+
+		/* Interval for polling is set to about 5 - 10 ms */
+		usleep_range(5000, 10000);
+	} while (time_before(jiffies, timeout));
+
+	pm_runtime_put(data->dev);
+
+	dev_warn(data->dev, "Timeout waiting for role-switch\n");
+	return -ETIMEDOUT;
+}
+
+static enum usb_role intel_xhci_usb_get_role(struct usb_role_switch *sw)
+{
+	struct intel_xhci_usb_data *data = usb_role_switch_get_drvdata(sw);
+	enum usb_role role;
+	u32 val;
+
+	pm_runtime_get_sync(data->dev);
+	val = readl(data->base + DUAL_ROLE_CFG0);
+	pm_runtime_put(data->dev);
+
+	if (!(val & SW_IDPIN))
+		role = USB_ROLE_HOST;
+	else if (val & SW_VBUS_VALID)
+		role = USB_ROLE_DEVICE;
+	else
+		role = USB_ROLE_NONE;
+
+	return role;
+}
+
+static int intel_xhci_usb_probe(struct platform_device *pdev)
+{
+	struct usb_role_switch_desc sw_desc = { };
+	struct device *dev = &pdev->dev;
+	struct intel_xhci_usb_data *data;
+	struct resource *res;
+	int ret;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
+	data->base = devm_ioremap(dev, res->start, resource_size(res));
+	if (!data->base)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, data);
+
+	ret = software_node_register(&intel_xhci_usb_node);
+	if (ret)
+		return ret;
+
+	sw_desc.set = intel_xhci_usb_set_role,
+	sw_desc.get = intel_xhci_usb_get_role,
+	sw_desc.allow_userspace_control = true,
+	sw_desc.fwnode = software_node_fwnode(&intel_xhci_usb_node);
+	sw_desc.driver_data = data;
+
+	data->dev = dev;
+	data->enable_sw_switch = !device_property_read_bool(dev,
+						"sw_switch_disable");
+
+	data->role_sw = usb_role_switch_register(dev, &sw_desc);
+	if (IS_ERR(data->role_sw)) {
+		fwnode_handle_put(sw_desc.fwnode);
+		return PTR_ERR(data->role_sw);
+	}
+
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	return 0;
+}
+
+static int intel_xhci_usb_remove(struct platform_device *pdev)
+{
+	struct intel_xhci_usb_data *data = platform_get_drvdata(pdev);
+
+	pm_runtime_disable(&pdev->dev);
+
+	usb_role_switch_unregister(data->role_sw);
+	fwnode_handle_put(software_node_fwnode(&intel_xhci_usb_node));
+
+	return 0;
+}
+
+static const struct platform_device_id intel_xhci_usb_table[] = {
+	{ .name = DRV_NAME },
+	{}
+};
+MODULE_DEVICE_TABLE(platform, intel_xhci_usb_table);
+
+static struct platform_driver intel_xhci_usb_driver = {
+	.driver = {
+		.name = DRV_NAME,
+	},
+	.id_table = intel_xhci_usb_table,
+	.probe = intel_xhci_usb_probe,
+	.remove = intel_xhci_usb_remove,
+};
+
+module_platform_driver(intel_xhci_usb_driver);
+
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_DESCRIPTION("Intel XHCI USB role switch driver");
+MODULE_LICENSE("GPL");