4 files changed, 673 insertions, 0 deletions
diff --git a/drivers/usb/roles/Kconfig b/drivers/usb/roles/Kconfig
new file mode 100644
index 000000000..f8b31aa67
--- /dev/null
+++ b/drivers/usb/roles/Kconfig
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config USB_ROLE_SWITCH
+	tristate "USB Role Switch Support"
+	help
+	  USB Role Switch is a device that can select the USB role - host or
+	  device - for a USB port (connector). In most cases dual-role capable
+	  USB controller will also represent the switch, but on some platforms
+	  multiplexer/demultiplexer switch is used to route the data lines on
+	  the USB connector between separate USB host and device controllers.
+
+	  Say Y here if your USB connectors support both device and host roles.
+	  To compile the driver as module, choose M here: the module will be
+	  called roles.ko.
+
+if USB_ROLE_SWITCH
+
+config USB_ROLES_INTEL_XHCI
+	tristate "Intel XHCI USB Role Switch"
+	depends on ACPI && X86
+	help
+	  Driver for the internal USB role switch for switching the USB data
+	  lines between the xHCI host controller and the dwc3 gadget controller
+	  found on various Intel SoCs.
+
+	  To compile the driver as a module, choose M here: the module will
+	  be called intel-xhci-usb-role-switch.
+
+endif # USB_ROLE_SWITCH
diff --git a/drivers/usb/roles/Makefile b/drivers/usb/roles/Makefile
new file mode 100644
index 000000000..757a7d279
--- /dev/null
+++ b/drivers/usb/roles/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_USB_ROLE_SWITCH)		+= roles.o
+roles-y					:= class.o
+obj-$(CONFIG_USB_ROLES_INTEL_XHCI)	+= intel-xhci-usb-role-switch.o
diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
new file mode 100644
index 000000000..32e6d19f7
--- /dev/null
+++ b/drivers/usb/roles/class.c
@@ -0,0 +1,410 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB Role Switch Support
+ *
+ * Copyright (C) 2018 Intel Corporation
+ * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ *         Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include <linux/usb/role.h>
+#include <linux/property.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+
+static struct class *role_class;
+
+struct usb_role_switch {
+	struct device dev;
+	struct mutex lock; /* device lock*/
+	enum usb_role role;
+
+	/* From descriptor */
+	struct device *usb2_port;
+	struct device *usb3_port;
+	struct device *udc;
+	usb_role_switch_set_t set;
+	usb_role_switch_get_t get;
+	bool allow_userspace_control;
+};
+
+#define to_role_switch(d)	container_of(d, struct usb_role_switch, dev)
+
+/**
+ * usb_role_switch_set_role - Set USB role for a switch
+ * @sw: USB role switch
+ * @role: USB role to be switched to
+ *
+ * Set USB role @role for @sw.
+ */
+int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role)
+{
+	int ret;
+
+	if (IS_ERR_OR_NULL(sw))
+		return 0;
+
+	mutex_lock(&sw->lock);
+
+	ret = sw->set(sw, role);
+	if (!ret) {
+		sw->role = role;
+		kobject_uevent(&sw->dev.kobj, KOBJ_CHANGE);
+	}
+
+	mutex_unlock(&sw->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_set_role);
+
+/**
+ * usb_role_switch_get_role - Get the USB role for a switch
+ * @sw: USB role switch
+ *
+ * Depending on the role-switch-driver this function returns either a cached
+ * value of the last set role, or reads back the actual value from the hardware.
+ */
+enum usb_role usb_role_switch_get_role(struct usb_role_switch *sw)
+{
+	enum usb_role role;
+
+	if (IS_ERR_OR_NULL(sw))
+		return USB_ROLE_NONE;
+
+	mutex_lock(&sw->lock);
+
+	if (sw->get)
+		role = sw->get(sw);
+	else
+		role = sw->role;
+
+	mutex_unlock(&sw->lock);
+
+	return role;
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_get_role);
+
+static void *usb_role_switch_match(struct fwnode_handle *fwnode, const char *id,
+				   void *data)
+{
+	struct device *dev;
+
+	if (id && !fwnode_property_present(fwnode, id))
+		return NULL;
+
+	dev = class_find_device_by_fwnode(role_class, fwnode);
+
+	return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);
+}
+
+static struct usb_role_switch *
+usb_role_switch_is_parent(struct fwnode_handle *fwnode)
+{
+	struct fwnode_handle *parent = fwnode_get_parent(fwnode);
+	struct device *dev;
+
+	if (!fwnode_property_present(parent, "usb-role-switch")) {
+		fwnode_handle_put(parent);
+		return NULL;
+	}
+
+	dev = class_find_device_by_fwnode(role_class, parent);
+	fwnode_handle_put(parent);
+	return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);
+}
+
+/**
+ * usb_role_switch_get - Find USB role switch linked with the caller
+ * @dev: The caller device
+ *
+ * Finds and returns role switch linked with @dev. The reference count for the
+ * found switch is incremented.
+ */
+struct usb_role_switch *usb_role_switch_get(struct device *dev)
+{
+	struct usb_role_switch *sw;
+
+	sw = usb_role_switch_is_parent(dev_fwnode(dev));
+	if (!sw)
+		sw = device_connection_find_match(dev, "usb-role-switch", NULL,
+						  usb_role_switch_match);
+
+	if (!IS_ERR_OR_NULL(sw))
+		WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
+
+	return sw;
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_get);
+
+/**
+ * fwnode_usb_role_switch_get - Find USB role switch linked with the caller
+ * @fwnode: The caller device node
+ *
+ * This is similar to the usb_role_switch_get() function above, but it searches
+ * the switch using fwnode instead of device entry.
+ */
+struct usb_role_switch *fwnode_usb_role_switch_get(struct fwnode_handle *fwnode)
+{
+	struct usb_role_switch *sw;
+
+	sw = usb_role_switch_is_parent(fwnode);
+	if (!sw)
+		sw = fwnode_connection_find_match(fwnode, "usb-role-switch",
+						  NULL, usb_role_switch_match);
+	if (!IS_ERR_OR_NULL(sw))
+		WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
+
+	return sw;
+}
+EXPORT_SYMBOL_GPL(fwnode_usb_role_switch_get);
+
+/**
+ * usb_role_switch_put - Release handle to a switch
+ * @sw: USB Role Switch
+ *
+ * Decrement reference count for @sw.
+ */
+void usb_role_switch_put(struct usb_role_switch *sw)
+{
+	if (!IS_ERR_OR_NULL(sw)) {
+		module_put(sw->dev.parent->driver->owner);
+		put_device(&sw->dev);
+	}
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_put);
+
+/**
+ * usb_role_switch_find_by_fwnode - Find USB role switch with its fwnode
+ * @fwnode: fwnode of the USB Role Switch
+ *
+ * Finds and returns role switch with @fwnode. The reference count for the
+ * found switch is incremented.
+ */
+struct usb_role_switch *
+usb_role_switch_find_by_fwnode(const struct fwnode_handle *fwnode)
+{
+	struct device *dev;
+
+	if (!fwnode)
+		return NULL;
+
+	dev = class_find_device_by_fwnode(role_class, fwnode);
+	if (dev)
+		WARN_ON(!try_module_get(dev->parent->driver->owner));
+
+	return dev ? to_role_switch(dev) : NULL;
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_find_by_fwnode);
+
+static umode_t
+usb_role_switch_is_visible(struct kobject *kobj, struct attribute *attr, int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct usb_role_switch *sw = to_role_switch(dev);
+
+	if (sw->allow_userspace_control)
+		return attr->mode;
+
+	return 0;
+}
+
+static const char * const usb_roles[] = {
+	[USB_ROLE_NONE]		= "none",
+	[USB_ROLE_HOST]		= "host",
+	[USB_ROLE_DEVICE]	= "device",
+};
+
+const char *usb_role_string(enum usb_role role)
+{
+	if (role < 0 || role >= ARRAY_SIZE(usb_roles))
+		return "unknown";
+
+	return usb_roles[role];
+}
+EXPORT_SYMBOL_GPL(usb_role_string);
+
+static ssize_t
+role_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct usb_role_switch *sw = to_role_switch(dev);
+	enum usb_role role = usb_role_switch_get_role(sw);
+
+	return sprintf(buf, "%s\n", usb_roles[role]);
+}
+
+static ssize_t role_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t size)
+{
+	struct usb_role_switch *sw = to_role_switch(dev);
+	int ret;
+
+	ret = sysfs_match_string(usb_roles, buf);
+	if (ret < 0) {
+		bool res;
+
+		/* Extra check if the user wants to disable the switch */
+		ret = kstrtobool(buf, &res);
+		if (ret || res)
+			return -EINVAL;
+	}
+
+	ret = usb_role_switch_set_role(sw, ret);
+	if (ret)
+		return ret;
+
+	return size;
+}
+static DEVICE_ATTR_RW(role);
+
+static struct attribute *usb_role_switch_attrs[] = {
+	&dev_attr_role.attr,
+	NULL,
+};
+
+static const struct attribute_group usb_role_switch_group = {
+	.is_visible = usb_role_switch_is_visible,
+	.attrs = usb_role_switch_attrs,
+};
+
+static const struct attribute_group *usb_role_switch_groups[] = {
+	&usb_role_switch_group,
+	NULL,
+};
+
+static int
+usb_role_switch_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	int ret;
+
+	ret = add_uevent_var(env, "USB_ROLE_SWITCH=%s", dev_name(dev));
+	if (ret)
+		dev_err(dev, "failed to add uevent USB_ROLE_SWITCH\n");
+
+	return ret;
+}
+
+static void usb_role_switch_release(struct device *dev)
+{
+	struct usb_role_switch *sw = to_role_switch(dev);
+
+	kfree(sw);
+}
+
+static const struct device_type usb_role_dev_type = {
+	.name = "usb_role_switch",
+	.groups = usb_role_switch_groups,
+	.uevent = usb_role_switch_uevent,
+	.release = usb_role_switch_release,
+};
+
+/**
+ * usb_role_switch_register - Register USB Role Switch
+ * @parent: Parent device for the switch
+ * @desc: Description of the switch
+ *
+ * USB Role Switch is a device capable or choosing the role for USB connector.
+ * On platforms where the USB controller is dual-role capable, the controller
+ * driver will need to register the switch. On platforms where the USB host and
+ * USB device controllers behind the connector are separate, there will be a
+ * mux, and the driver for that mux will need to register the switch.
+ *
+ * Returns handle to a new role switch or ERR_PTR. The content of @desc is
+ * copied.
+ */
+struct usb_role_switch *
+usb_role_switch_register(struct device *parent,
+			 const struct usb_role_switch_desc *desc)
+{
+	struct usb_role_switch *sw;
+	int ret;
+
+	if (!desc || !desc->set)
+		return ERR_PTR(-EINVAL);
+
+	sw = kzalloc(sizeof(*sw), GFP_KERNEL);
+	if (!sw)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&sw->lock);
+
+	sw->allow_userspace_control = desc->allow_userspace_control;
+	sw->usb2_port = desc->usb2_port;
+	sw->usb3_port = desc->usb3_port;
+	sw->udc = desc->udc;
+	sw->set = desc->set;
+	sw->get = desc->get;
+
+	sw->dev.parent = parent;
+	sw->dev.fwnode = desc->fwnode;
+	sw->dev.class = role_class;
+	sw->dev.type = &usb_role_dev_type;
+	dev_set_drvdata(&sw->dev, desc->driver_data);
+	dev_set_name(&sw->dev, "%s-role-switch",
+		     desc->name ? desc->name : dev_name(parent));
+
+	ret = device_register(&sw->dev);
+	if (ret) {
+		put_device(&sw->dev);
+		return ERR_PTR(ret);
+	}
+
+	/* TODO: Symlinks for the host port and the device controller. */
+
+	return sw;
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_register);
+
+/**
+ * usb_role_switch_unregister - Unregsiter USB Role Switch
+ * @sw: USB Role Switch
+ *
+ * Unregister switch that was registered with usb_role_switch_register().
+ */
+void usb_role_switch_unregister(struct usb_role_switch *sw)
+{
+	if (!IS_ERR_OR_NULL(sw))
+		device_unregister(&sw->dev);
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_unregister);
+
+/**
+ * usb_role_switch_set_drvdata - Assign private data pointer to a switch
+ * @sw: USB Role Switch
+ * @data: Private data pointer
+ */
+void usb_role_switch_set_drvdata(struct usb_role_switch *sw, void *data)
+{
+	dev_set_drvdata(&sw->dev, data);
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_set_drvdata);
+
+/**
+ * usb_role_switch_get_drvdata - Get the private data pointer of a switch
+ * @sw: USB Role Switch
+ */
+void *usb_role_switch_get_drvdata(struct usb_role_switch *sw)
+{
+	return dev_get_drvdata(&sw->dev);
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_get_drvdata);
+
+static int __init usb_roles_init(void)
+{
+	role_class = class_create(THIS_MODULE, "usb_role");
+	return PTR_ERR_OR_ZERO(role_class);
+}
+subsys_initcall(usb_roles_init);
+
+static void __exit usb_roles_exit(void)
+{
+	class_destroy(role_class);
+}
+module_exit(usb_roles_exit);
+
+MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("USB Role Class");
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");