1 files changed, 143 insertions, 146 deletions

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index 85b194011a16..7886497253cc 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/list.h>
+#include <linux/idr.h>
 #include <linux/err.h>
 #include <linux/dma-mapping.h>
 #include <linux/sched/task_stack.h>
@@ -23,6 +24,10 @@
 
 #include "trace.h"
 
+static DEFINE_IDA(gadget_id_numbers);
+
+static struct bus_type gadget_bus_type;
+
 /**
  * struct usb_udc - describes one usb device controller
  * @driver: the gadget driver pointer. For use by the class code
@@ -47,11 +52,9 @@ struct usb_udc {
 
 static struct class *udc_class;
 static LIST_HEAD(udc_list);
-static LIST_HEAD(gadget_driver_pending_list);
-static DEFINE_MUTEX(udc_lock);
 
-static int udc_bind_to_driver(struct usb_udc *udc,
-		struct usb_gadget_driver *driver);
+/* Protects udc_list, udc->driver, driver->is_bound, and related calls */
+static DEFINE_MUTEX(udc_lock);
 
 /* ------------------------------------------------------------------------- */
 
@@ -1238,38 +1241,16 @@ static void usb_udc_nop_release(struct device *dev)
 	dev_vdbg(dev, "%s\n", __func__);
 }
 
-/* should be called with udc_lock held */
-static int check_pending_gadget_drivers(struct usb_udc *udc)
-{
-	struct usb_gadget_driver *driver;
-	int ret = 0;
-
-	list_for_each_entry(driver, &gadget_driver_pending_list, pending)
-		if (!driver->udc_name || strcmp(driver->udc_name,
-						dev_name(&udc->dev)) == 0) {
-			ret = udc_bind_to_driver(udc, driver);
-			if (ret != -EPROBE_DEFER)
-				list_del_init(&driver->pending);
-			break;
-		}
-
-	return ret;
-}
-
 /**
  * usb_initialize_gadget - initialize a gadget and its embedded struct device
  * @parent: the parent device to this udc. Usually the controller driver's
  * device.
  * @gadget: the gadget to be initialized.
  * @release: a gadget release function.
- *
- * Returns zero on success, negative errno otherwise.
- * Calls the gadget release function in the latter case.
  */
 void usb_initialize_gadget(struct device *parent, struct usb_gadget *gadget,
 		void (*release)(struct device *dev))
 {
-	dev_set_name(&gadget->dev, "gadget");
 	INIT_WORK(&gadget->work, usb_gadget_state_work);
 	gadget->dev.parent = parent;
 
@@ -1279,6 +1260,7 @@ void usb_initialize_gadget(struct device *parent, struct usb_gadget *gadget,
 		gadget->dev.release = usb_udc_nop_release;
 
 	device_initialize(&gadget->dev);
+	gadget->dev.bus = &gadget_bus_type;
 }
 EXPORT_SYMBOL_GPL(usb_initialize_gadget);
 
@@ -1308,10 +1290,6 @@ int usb_add_gadget(struct usb_gadget *gadget)
 	if (ret)
 		goto err_put_udc;
 
-	ret = device_add(&gadget->dev);
-	if (ret)
-		goto err_put_udc;
-
 	udc->gadget = gadget;
 	gadget->udc = udc;
 
@@ -1319,6 +1297,7 @@ int usb_add_gadget(struct usb_gadget *gadget)
 
 	mutex_lock(&udc_lock);
 	list_add_tail(&udc->list, &udc_list);
+	mutex_unlock(&udc_lock);
 
 	ret = device_add(&udc->dev);
 	if (ret)
@@ -1327,25 +1306,30 @@ int usb_add_gadget(struct usb_gadget *gadget)
 	usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED);
 	udc->vbus = true;
 
-	/* pick up one of pending gadget drivers */
-	ret = check_pending_gadget_drivers(udc);
-	if (ret)
+	ret = ida_alloc(&gadget_id_numbers, GFP_KERNEL);
+	if (ret < 0)
 		goto err_del_udc;
+	gadget->id_number = ret;
+	dev_set_name(&gadget->dev, "gadget.%d", ret);
 
-	mutex_unlock(&udc_lock);
+	ret = device_add(&gadget->dev);
+	if (ret)
+		goto err_free_id;
 
 	return 0;
 
+ err_free_id:
+	ida_free(&gadget_id_numbers, gadget->id_number);
+
  err_del_udc:
 	flush_work(&gadget->work);
 	device_del(&udc->dev);
 
  err_unlist_udc:
+	mutex_lock(&udc_lock);
 	list_del(&udc->list);
 	mutex_unlock(&udc_lock);
 
-	device_del(&gadget->dev);
-
  err_put_udc:
 	put_device(&udc->dev);
 
@@ -1421,30 +1405,11 @@ int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget)
 }
 EXPORT_SYMBOL_GPL(usb_add_gadget_udc);
 
-static void usb_gadget_remove_driver(struct usb_udc *udc)
-{
-	dev_dbg(&udc->dev, "unregistering UDC driver [%s]\n",
-			udc->driver->function);
-
-	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
-
-	usb_gadget_disconnect(udc->gadget);
-	usb_gadget_disable_async_callbacks(udc);
-	if (udc->gadget->irq)
-		synchronize_irq(udc->gadget->irq);
-	udc->driver->unbind(udc->gadget);
-	usb_gadget_udc_stop(udc);
-
-	udc->driver = NULL;
-	udc->gadget->dev.driver = NULL;
-}
-
 /**
- * usb_del_gadget - deletes @udc from udc_list
- * @gadget: the gadget to be removed.
+ * usb_del_gadget - deletes a gadget and unregisters its udc
+ * @gadget: the gadget to be deleted.
  *
- * This will call usb_gadget_unregister_driver() if
- * the @udc is still busy.
+ * This will unbind @gadget, if it is bound.
  * It will not do a final usb_put_gadget().
  */
 void usb_del_gadget(struct usb_gadget *gadget)
@@ -1458,25 +1423,19 @@ void usb_del_gadget(struct usb_gadget *gadget)
 
 	mutex_lock(&udc_lock);
 	list_del(&udc->list);
-
-	if (udc->driver) {
-		struct usb_gadget_driver *driver = udc->driver;
-
-		usb_gadget_remove_driver(udc);
-		list_add(&driver->pending, &gadget_driver_pending_list);
-	}
 	mutex_unlock(&udc_lock);
 
 	kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
 	flush_work(&gadget->work);
-	device_unregister(&udc->dev);
 	device_del(&gadget->dev);
+	ida_free(&gadget_id_numbers, gadget->id_number);
+	device_unregister(&udc->dev);
 }
 EXPORT_SYMBOL_GPL(usb_del_gadget);
 
 /**
- * usb_del_gadget_udc - deletes @udc from udc_list
- * @gadget: the gadget to be removed.
+ * usb_del_gadget_udc - unregisters a gadget
+ * @gadget: the gadget to be unregistered.
  *
  * Calls usb_del_gadget() and does a final usb_put_gadget().
  */
@@ -1489,123 +1448,147 @@ EXPORT_SYMBOL_GPL(usb_del_gadget_udc);
 
 /* ------------------------------------------------------------------------- */
 
-static int udc_bind_to_driver(struct usb_udc *udc, struct usb_gadget_driver *driver)
+static int gadget_match_driver(struct device *dev, struct device_driver *drv)
 {
-	int ret;
+	struct usb_gadget *gadget = dev_to_usb_gadget(dev);
+	struct usb_udc *udc = gadget->udc;
+	struct usb_gadget_driver *driver = container_of(drv,
+			struct usb_gadget_driver, driver);
 
-	dev_dbg(&udc->dev, "registering UDC driver [%s]\n",
-			driver->function);
+	/* If the driver specifies a udc_name, it must match the UDC's name */
+	if (driver->udc_name &&
+			strcmp(driver->udc_name, dev_name(&udc->dev)) != 0)
+		return 0;
+
+	/* If the driver is already bound to a gadget, it doesn't match */
+	if (driver->is_bound)
+		return 0;
+
+	/* Otherwise any gadget driver matches any UDC */
+	return 1;
+}
 
+static int gadget_bind_driver(struct device *dev)
+{
+	struct usb_gadget *gadget = dev_to_usb_gadget(dev);
+	struct usb_udc *udc = gadget->udc;
+	struct usb_gadget_driver *driver = container_of(dev->driver,
+			struct usb_gadget_driver, driver);
+	int ret = 0;
+
+	mutex_lock(&udc_lock);
+	if (driver->is_bound) {
+		mutex_unlock(&udc_lock);
+		return -ENXIO;		/* Driver binds to only one gadget */
+	}
+	driver->is_bound = true;
 	udc->driver = driver;
-	udc->gadget->dev.driver = &driver->driver;
+	mutex_unlock(&udc_lock);
+
+	dev_dbg(&udc->dev, "binding gadget driver [%s]\n", driver->function);
 
 	usb_gadget_udc_set_speed(udc, driver->max_speed);
 
+	mutex_lock(&udc_lock);
 	ret = driver->bind(udc->gadget, driver);
 	if (ret)
-		goto err1;
+		goto err_bind;
+
 	ret = usb_gadget_udc_start(udc);
-	if (ret) {
-		driver->unbind(udc->gadget);
-		goto err1;
-	}
+	if (ret)
+		goto err_start;
 	usb_gadget_enable_async_callbacks(udc);
 	usb_udc_connect_control(udc);
+	mutex_unlock(&udc_lock);
 
 	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
 	return 0;
-err1:
+
+ err_start:
+	driver->unbind(udc->gadget);
+
+ err_bind:
 	if (ret != -EISNAM)
 		dev_err(&udc->dev, "failed to start %s: %d\n",
-			udc->driver->function, ret);
+			driver->function, ret);
+
 	udc->driver = NULL;
-	udc->gadget->dev.driver = NULL;
+	driver->is_bound = false;
+	mutex_unlock(&udc_lock);
+
 	return ret;
 }
 
-int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
+static void gadget_unbind_driver(struct device *dev)
 {
-	struct usb_udc		*udc = NULL, *iter;
-	int			ret = -ENODEV;
+	struct usb_gadget *gadget = dev_to_usb_gadget(dev);
+	struct usb_udc *udc = gadget->udc;
+	struct usb_gadget_driver *driver = udc->driver;
+
+	dev_dbg(&udc->dev, "unbinding gadget driver [%s]\n", driver->function);
+
+	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
+
+	mutex_lock(&udc_lock);
+	usb_gadget_disconnect(gadget);
+	usb_gadget_disable_async_callbacks(udc);
+	if (gadget->irq)
+		synchronize_irq(gadget->irq);
+	udc->driver->unbind(gadget);
+	usb_gadget_udc_stop(udc);
+
+	driver->is_bound = false;
+	udc->driver = NULL;
+	mutex_unlock(&udc_lock);
+}
+
+/* ------------------------------------------------------------------------- */
+
+int usb_gadget_register_driver_owner(struct usb_gadget_driver *driver,
+		struct module *owner, const char *mod_name)
+{
+	int ret;
 
 	if (!driver || !driver->bind || !driver->setup)
 		return -EINVAL;
 
+	driver->driver.bus = &gadget_bus_type;
+	driver->driver.owner = owner;
+	driver->driver.mod_name = mod_name;
+	ret = driver_register(&driver->driver);
+	if (ret) {
+		pr_warn("%s: driver registration failed: %d\n",
+				driver->function, ret);
+		return ret;
+	}
+
 	mutex_lock(&udc_lock);
-	if (driver->udc_name) {
-		list_for_each_entry(iter, &udc_list, list) {
-			ret = strcmp(driver->udc_name, dev_name(&iter->dev));
-			if (ret)
-				continue;
-			udc = iter;
-			break;
-		}
-		if (ret)
-			ret = -ENODEV;
-		else if (udc->driver)
+	if (!driver->is_bound) {
+		if (driver->match_existing_only) {
+			pr_warn("%s: couldn't find an available UDC or it's busy\n",
+					driver->function);
 			ret = -EBUSY;
-		else
-			goto found;
-	} else {
-		list_for_each_entry(iter, &udc_list, list) {
-			/* For now we take the first one */
-			if (iter->driver)
-				continue;
-			udc = iter;
-			goto found;
+		} else {
+			pr_info("%s: couldn't find an available UDC\n",
+					driver->function);
+			ret = 0;
 		}
 	}
-
-	if (!driver->match_existing_only) {
-		list_add_tail(&driver->pending, &gadget_driver_pending_list);
-		pr_info("couldn't find an available UDC - added [%s] to list of pending drivers\n",
-			driver->function);
-		ret = 0;
-	}
-
 	mutex_unlock(&udc_lock);
+
 	if (ret)
-		pr_warn("couldn't find an available UDC or it's busy: %d\n", ret);
-	return ret;
-found:
-	ret = udc_bind_to_driver(udc, driver);
-	mutex_unlock(&udc_lock);
+		driver_unregister(&driver->driver);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(usb_gadget_probe_driver);
+EXPORT_SYMBOL_GPL(usb_gadget_register_driver_owner);
 
 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
 {
-	struct usb_udc		*udc = NULL;
-	int			ret = -ENODEV;
-
 	if (!driver || !driver->unbind)
 		return -EINVAL;
 
-	mutex_lock(&udc_lock);
-	list_for_each_entry(udc, &udc_list, list) {
-		if (udc->driver == driver) {
-			usb_gadget_remove_driver(udc);
-			usb_gadget_set_state(udc->gadget,
-					     USB_STATE_NOTATTACHED);
-
-			/* Maybe there is someone waiting for this UDC? */
-			check_pending_gadget_drivers(udc);
-			/*
-			 * For now we ignore bind errors as probably it's
-			 * not a valid reason to fail other's gadget unbind
-			 */
-			ret = 0;
-			break;
-		}
-	}
-
-	if (ret) {
-		list_del(&driver->pending);
-		ret = 0;
-	}
-	mutex_unlock(&udc_lock);
-	return ret;
+	driver_unregister(&driver->driver);
+	return 0;
 }
 EXPORT_SYMBOL_GPL(usb_gadget_unregister_driver);
 
@@ -1757,8 +1740,17 @@ static int usb_udc_uevent(struct device *dev, struct kobj_uevent_env *env)
 	return 0;
 }
 
+static struct bus_type gadget_bus_type = {
+	.name = "gadget",
+	.probe = gadget_bind_driver,
+	.remove = gadget_unbind_driver,
+	.match = gadget_match_driver,
+};
+
 static int __init usb_udc_init(void)
 {
+	int rc;
+
 	udc_class = class_create(THIS_MODULE, "udc");
 	if (IS_ERR(udc_class)) {
 		pr_err("failed to create udc class --> %ld\n",
@@ -1767,12 +1759,17 @@ static int __init usb_udc_init(void)
 	}
 
 	udc_class->dev_uevent = usb_udc_uevent;
-	return 0;
+
+	rc = bus_register(&gadget_bus_type);
+	if (rc)
+		class_destroy(udc_class);
+	return rc;
 }
 subsys_initcall(usb_udc_init);
 
 static void __exit usb_udc_exit(void)
 {
+	bus_unregister(&gadget_bus_type);
 	class_destroy(udc_class);
 }
 module_exit(usb_udc_exit);