[v6,02/35] component: Introduce the aggregate bus_type

diff --git a/drivers/base/component.c b/drivers/base/component.c
index 34f9e0802719..dc748ef0b23b 100644
--- a/drivers/base/component.c
+++ b/drivers/base/component.c
@@ -4,10 +4,14 @@ 
  */
 #include <linux/component.h>
 #include <linux/device.h>
+#include <linux/idr.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/debugfs.h>
+#include <linux/pm_runtime.h>
+
+#include "base.h"
 
 /**
  * DOC: overview
@@ -31,8 +35,8 @@ 
  *
  * Aggregate drivers first assemble a component match list of what they need
  * using component_match_add(). This is then registered as an aggregate driver
- * using component_master_add_with_match(), and unregistered using
- * component_master_del().
+ * using component_aggregate_register(), and unregistered using
+ * component_aggregate_unregister().
  */
 
 struct component;
@@ -53,14 +57,20 @@  struct component_match {
 };
 
 struct aggregate_device {
-	struct list_head node;
-	bool bound;
-
 	const struct component_master_ops *ops;
 	struct device *parent;
+	struct device dev;
 	struct component_match *match;
+	struct aggregate_driver *adrv;
+
+	int id;
 };
 
+static inline struct aggregate_device *to_aggregate_device(struct device *d)
+{
+	return container_of(d, struct aggregate_device, dev);
+}
+
 struct component {
 	struct list_head node;
 	struct aggregate_device *adev;
@@ -69,11 +79,12 @@  struct component {
 	const struct component_ops *ops;
 	int subcomponent;
 	struct device *dev;
+	struct device_link *link;
 };
 
 static DEFINE_MUTEX(component_mutex);
 static LIST_HEAD(component_list);
-static LIST_HEAD(aggregate_devices);
+static DEFINE_IDA(aggregate_ida);
 
 #ifdef CONFIG_DEBUG_FS
 
@@ -89,7 +100,7 @@  static int component_devices_show(struct seq_file *s, void *data)
 	seq_printf(s, "%-40s %20s\n", "aggregate_device name", "status");
 	seq_puts(s, "-------------------------------------------------------------\n");
 	seq_printf(s, "%-40s %20s\n\n",
-		   dev_name(m->parent), m->bound ? "bound" : "not bound");
+		   dev_name(m->parent), m->dev.driver ? "bound" : "not bound");
 
 	seq_printf(s, "%-40s %20s\n", "device name", "status");
 	seq_puts(s, "-------------------------------------------------------------\n");
@@ -137,16 +148,21 @@  static void component_debugfs_del(struct aggregate_device *m)
 
 #endif
 
-static struct aggregate_device *__aggregate_find(struct device *parent,
-	const struct component_master_ops *ops)
+struct aggregate_bus_find_data {
+	const struct component_master_ops *ops;
+	struct device *parent;
+};
+
+static int aggregate_bus_find_match(struct device *dev, const void *_data)
 {
-	struct aggregate_device *m;
+	struct aggregate_device *adev = to_aggregate_device(dev);
+	const struct aggregate_bus_find_data *data = _data;
 
-	list_for_each_entry(m, &aggregate_devices, node)
-		if (m->parent == parent && (!ops || m->ops == ops))
-			return m;
+	if (adev->parent == data->parent &&
+	    (!data->ops || adev->ops == data->ops))
+		return 1;
 
-	return NULL;
+	return 0;
 }
 
 static struct component *find_component(struct aggregate_device *adev,
@@ -173,7 +189,6 @@  static int find_components(struct aggregate_device *adev)
 {
 	struct component_match *match = adev->match;
 	size_t i;
-	int ret = 0;
 
 	/*
 	 * Scan the array of match functions and attach
@@ -182,6 +197,7 @@  static int find_components(struct aggregate_device *adev)
 	for (i = 0; i < match->num; i++) {
 		struct component_match_array *mc = &match->compare[i];
 		struct component *c;
+		bool duplicate;
 
 		dev_dbg(adev->parent, "Looking for component %zu\n", i);
 
@@ -189,20 +205,27 @@  static int find_components(struct aggregate_device *adev)
 			continue;
 
 		c = find_component(adev, mc);
-		if (!c) {
-			ret = -ENXIO;
-			break;
-		}
+		if (!c)
+			return 0;
 
+		duplicate = !!c->adev;
 		dev_dbg(adev->parent, "found component %s, duplicate %u\n",
-			dev_name(c->dev), !!c->adev);
+			dev_name(c->dev), duplicate);
 
 		/* Attach this component to the adev */
-		match->compare[i].duplicate = !!c->adev;
+		match->compare[i].duplicate = duplicate;
 		match->compare[i].component = c;
+		if (duplicate)
+			continue;
+
+		/* Matches put in component_del() */
+		get_device(&adev->dev);
+		c->link = device_link_add(&adev->dev, c->dev,
+					  DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME);
 		c->adev = adev;
 	}
-	return ret;
+
+	return 1;
 }
 
 /* Detach component from associated aggregate_device */
@@ -216,73 +239,6 @@  static void remove_component(struct aggregate_device *adev, struct component *c)
 			adev->match->compare[i].component = NULL;
 }
 
-/*
- * Try to bring up an aggregate device.  If component is NULL, we're interested
- * in this aggregate device, otherwise it's a component which must be present
- * to try and bring up the aggregate device.
- *
- * Returns 1 for successful bringup, 0 if not ready, or -ve errno.
- */
-static int try_to_bring_up_aggregate_device(struct aggregate_device *adev,
-	struct component *component)
-{
-	int ret;
-
-	dev_dbg(adev->parent, "trying to bring up adev\n");
-
-	if (find_components(adev)) {
-		dev_dbg(adev->parent, "master has incomplete components\n");
-		return 0;
-	}
-
-	if (component && component->adev != adev) {
-		dev_dbg(adev->parent, "master is not for this component (%s)\n",
-			dev_name(component->dev));
-		return 0;
-	}
-
-	if (!devres_open_group(adev->parent, adev, GFP_KERNEL))
-		return -ENOMEM;
-
-	/* Found all components */
-	ret = adev->ops->bind(adev->parent);
-	if (ret < 0) {
-		devres_release_group(adev->parent, NULL);
-		if (ret != -EPROBE_DEFER)
-			dev_info(adev->parent, "adev bind failed: %d\n", ret);
-		return ret;
-	}
-
-	devres_close_group(adev->parent, NULL);
-	adev->bound = true;
-	return 1;
-}
-
-static int try_to_bring_up_masters(struct component *component)
-{
-	struct aggregate_device *adev;
-	int ret = 0;
-
-	list_for_each_entry(adev, &aggregate_devices, node) {
-		if (!adev->bound) {
-			ret = try_to_bring_up_aggregate_device(adev, component);
-			if (ret != 0)
-				break;
-		}
-	}
-
-	return ret;
-}
-
-static void take_down_aggregate_device(struct aggregate_device *adev)
-{
-	if (adev->bound) {
-		adev->ops->unbind(adev->parent);
-		devres_release_group(adev->parent, adev);
-		adev->bound = false;
-	}
-}
-
 static void devm_component_match_release(struct device *parent, void *res)
 {
 	struct component_match *match = res;
@@ -426,7 +382,6 @@  static void free_aggregate_device(struct aggregate_device *adev)
 	int i;
 
 	component_debugfs_del(adev);
-	list_del(&adev->node);
 
 	if (match) {
 		for (i = 0; i < match->num; i++) {
@@ -436,9 +391,201 @@  static void free_aggregate_device(struct aggregate_device *adev)
 		}
 	}
 
+	ida_free(&aggregate_ida, adev->id);
 	kfree(adev);
 }
 
+static void aggregate_device_release(struct device *dev)
+{
+	struct aggregate_device *adev = to_aggregate_device(dev);
+
+	free_aggregate_device(adev);
+}
+
+static int aggregate_device_match(struct device *dev, struct device_driver *drv)
+{
+	const struct aggregate_driver *adrv = to_aggregate_driver(drv);
+	struct aggregate_device *adev = to_aggregate_device(dev);
+	int ret;
+
+	/* Is this driver associated with this device */
+	if (adrv != adev->adrv)
+		return 0;
+
+	/* Should we start to assemble? */
+	mutex_lock(&component_mutex);
+	ret = find_components(adev);
+	mutex_unlock(&component_mutex);
+
+	return ret;
+}
+
+/* TODO: Remove once all aggregate drivers use component_aggregate_register() */
+static int component_probe_bind(struct aggregate_device *adev)
+{
+	return adev->ops->bind(adev->parent);
+}
+
+static void component_remove_unbind(struct aggregate_device *adev)
+{
+	adev->ops->unbind(adev->parent);
+}
+
+static int aggregate_driver_probe(struct device *dev)
+{
+	const struct aggregate_driver *adrv = to_aggregate_driver(dev->driver);
+	struct aggregate_device *adev = to_aggregate_device(dev);
+	bool modern = adrv->probe != component_probe_bind;
+	int ret;
+
+	/* Only do runtime PM when drivers migrate */
+	if (modern) {
+		pm_runtime_get_noresume(dev);
+		pm_runtime_set_active(dev);
+		pm_runtime_enable(dev);
+	}
+
+	mutex_lock(&component_mutex);
+	if (devres_open_group(adev->parent, adev, GFP_KERNEL)) {
+		ret = adrv->probe(adev);
+		if (ret)
+			devres_release_group(adev->parent, NULL);
+	} else {
+		ret = -ENOMEM;
+	}
+	devres_close_group(adev->parent, NULL);
+	mutex_unlock(&component_mutex);
+
+	if (ret && modern) {
+		pm_runtime_disable(dev);
+		pm_runtime_set_suspended(dev);
+		pm_runtime_put_noidle(dev);
+	}
+
+	return ret;
+}
+
+static void aggregate_driver_remove(struct device *dev)
+{
+	const struct aggregate_driver *adrv = to_aggregate_driver(dev->driver);
+	struct aggregate_device *adev = to_aggregate_device(dev);
+	bool modern = adrv->remove != component_remove_unbind;
+
+	/* Only do runtime PM when drivers migrate */
+	if (modern)
+		pm_runtime_get_sync(dev);
+	adrv->remove(to_aggregate_device(dev));
+	devres_release_group(adev->parent, adev);
+	if (!modern)
+		return;
+
+	pm_runtime_put_noidle(dev);
+
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_put_noidle(dev);
+}
+
+static void aggregate_driver_shutdown(struct device *dev)
+{
+	const struct aggregate_driver *adrv = to_aggregate_driver(dev->driver);
+
+	if (adrv && adrv->shutdown)
+		adrv->shutdown(to_aggregate_device(dev));
+}
+
+static struct bus_type aggregate_bus_type = {
+	.name		= "aggregate",
+	.match		= aggregate_device_match,
+	.probe		= aggregate_driver_probe,
+	.remove		= aggregate_driver_remove,
+	.shutdown	= aggregate_driver_shutdown,
+};
+
+/* Callers take ownership of return value, should call put_device() */
+static struct aggregate_device *__aggregate_find(struct device *parent,
+	const struct component_master_ops *ops)
+{
+	struct device *dev;
+	struct aggregate_bus_find_data data = {
+		.ops = ops,
+		.parent = parent,
+	};
+
+	dev = bus_find_device(&aggregate_bus_type, NULL, &data,
+			      aggregate_bus_find_match);
+
+	return dev ? to_aggregate_device(dev) : NULL;
+}
+
+static DEFINE_MUTEX(aggregate_mutex);
+
+static int aggregate_driver_register(struct aggregate_driver *adrv)
+{
+	int ret = 0;
+
+	mutex_lock(&aggregate_mutex);
+	if (!refcount_inc_not_zero(&adrv->count)) {
+		adrv->driver.bus = &aggregate_bus_type;
+		ret = driver_register(&adrv->driver);
+		if (!ret)
+			refcount_set(&adrv->count, 1);
+	}
+	mutex_unlock(&aggregate_mutex);
+
+	return ret;
+}
+
+static void aggregate_driver_unregister(struct aggregate_driver *adrv)
+{
+	if (refcount_dec_and_mutex_lock(&adrv->count, &aggregate_mutex)) {
+		driver_unregister(&adrv->driver);
+		mutex_unlock(&aggregate_mutex);
+	}
+}
+
+static struct aggregate_device *aggregate_device_add(struct device *parent,
+	const struct component_master_ops *ops, struct aggregate_driver *adrv,
+	struct component_match *match)
+{
+	struct aggregate_device *adev;
+	int ret, id;
+
+	/* Reallocate the match array for its true size */
+	ret = component_match_realloc(match, match->num);
+	if (ret)
+		return ERR_PTR(ret);
+
+	adev = kzalloc(sizeof(*adev), GFP_KERNEL);
+	if (!adev)
+		return ERR_PTR(-ENOMEM);
+
+	id = ida_alloc(&aggregate_ida, GFP_KERNEL);
+	if (id < 0) {
+		kfree(adev);
+		return ERR_PTR(id);
+	}
+
+	adev->id = id;
+	adev->parent = parent;
+	adev->dev.bus = &aggregate_bus_type;
+	adev->dev.release = aggregate_device_release;
+	adev->ops = ops;
+	adev->match = match;
+	adev->adrv = adrv;
+	dev_set_name(&adev->dev, "aggregate%d", id);
+
+	ret = device_register(&adev->dev);
+	if (ret) {
+		put_device(&adev->dev);
+		return ERR_PTR(ret);
+	}
+
+	component_debugfs_add(adev);
+
+	return adev;
+}
+
 /**
  * component_master_add_with_match - register an aggregate driver
  * @parent: parent device of the aggregate driver
@@ -450,42 +597,70 @@  static void free_aggregate_device(struct aggregate_device *adev)
  * @match are available, it will be assembled by calling
  * &component_master_ops.bind from @ops. Must be unregistered by calling
  * component_master_del().
+ *
+ * Deprecated: Use component_aggregate_register() instead.
  */
 int component_master_add_with_match(struct device *parent,
 	const struct component_master_ops *ops,
 	struct component_match *match)
 {
+	struct aggregate_driver *adrv;
 	struct aggregate_device *adev;
-	int ret;
-
-	/* Reallocate the match array for its true size */
-	ret = component_match_realloc(match, match->num);
-	if (ret)
-		return ret;
+	int ret = 0;
 
-	adev = kzalloc(sizeof(*adev), GFP_KERNEL);
-	if (!adev)
+	adrv = kzalloc(sizeof(*adrv), GFP_KERNEL);
+	if (!adrv)
 		return -ENOMEM;
 
-	adev->parent = parent;
-	adev->ops = ops;
-	adev->match = match;
+	adev = aggregate_device_add(parent, ops, adrv, match);
+	if (IS_ERR(adev)) {
+		ret = PTR_ERR(adev);
+		goto err;
+	}
 
-	component_debugfs_add(adev);
-	/* Add to the list of available aggregate devices. */
-	mutex_lock(&component_mutex);
-	list_add(&adev->node, &aggregate_devices);
+	adrv->probe = component_probe_bind;
+	adrv->remove = component_remove_unbind;
+	adrv->driver.owner = THIS_MODULE;
+	adrv->driver.name = dev_name(&adev->dev);
 
-	ret = try_to_bring_up_aggregate_device(adev, NULL);
+	ret = aggregate_driver_register(adrv);
+	if (!ret)
+		return 0;
 
-	if (ret < 0)
-		free_aggregate_device(adev);
+	put_device(&adev->dev);
+err:
+	kfree(adrv);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(component_master_add_with_match);
 
-	mutex_unlock(&component_mutex);
+/**
+ * component_aggregate_register - register an aggregate driver
+ * @parent: parent device of the aggregate driver
+ * @adrv: aggregate driver to register
+ *
+ * Registers a new aggregate driver consisting of the components added to @adrv.match
+ * by calling one of the component_match_add() functions. Once all components in
+ * @match are available, the aggregate driver will be assembled by calling
+ * &adrv.bind. Must be unregistered by calling component_aggregate_unregister().
+ */
+int component_aggregate_register(struct device *parent,
+	struct aggregate_driver *adrv, struct component_match *match)
+{
+	struct aggregate_device *adev;
+	int ret;
+
+	adev = aggregate_device_add(parent, NULL, adrv, match);
+	if (IS_ERR(adev))
+		return PTR_ERR(adev);
+
+	ret = aggregate_driver_register(adrv);
+	if (ret)
+		put_device(&adev->dev);
 
-	return ret < 0 ? ret : 0;
+	return ret;
 }
-EXPORT_SYMBOL_GPL(component_master_add_with_match);
+EXPORT_SYMBOL_GPL(component_aggregate_register);
 
 /**
  * component_master_del - unregister an aggregate driver
@@ -495,22 +670,60 @@  EXPORT_SYMBOL_GPL(component_master_add_with_match);
  * Unregisters an aggregate driver registered with
  * component_master_add_with_match(). If necessary the aggregate driver is first
  * disassembled by calling &component_master_ops.unbind from @ops.
+ *
+ * Deprecated: Use component_aggregate_unregister() instead.
  */
 void component_master_del(struct device *parent,
 	const struct component_master_ops *ops)
 {
 	struct aggregate_device *adev;
+	struct aggregate_driver *adrv;
+	struct device_driver *drv;
 
 	mutex_lock(&component_mutex);
 	adev = __aggregate_find(parent, ops);
+	mutex_unlock(&component_mutex);
+
 	if (adev) {
-		take_down_aggregate_device(adev);
-		free_aggregate_device(adev);
+		drv = adev->dev.driver;
+		if (drv) {
+			adrv = to_aggregate_driver(drv);
+			aggregate_driver_unregister(adrv);
+			kfree(adrv);
+		}
+
+		device_unregister(&adev->dev);
 	}
-	mutex_unlock(&component_mutex);
+	put_device(&adev->dev);
 }
 EXPORT_SYMBOL_GPL(component_master_del);
 
+/**
+ * component_aggregate_unregister - unregister an aggregate driver
+ * @parent: parent device of the aggregate driver
+ * @adrv: registered aggregate driver
+ *
+ * Unregisters an aggregate driver registered with
+ * component_aggregate_register(). If necessary the aggregate driver is first
+ * disassembled.
+ */
+void component_aggregate_unregister(struct device *parent,
+	struct aggregate_driver *adrv)
+{
+	struct aggregate_device *adev;
+
+	mutex_lock(&component_mutex);
+	adev = __aggregate_find(parent, NULL);
+	mutex_unlock(&component_mutex);
+
+	if (adev)
+		device_unregister(&adev->dev);
+	put_device(&adev->dev);
+
+	aggregate_driver_unregister(adrv);
+}
+EXPORT_SYMBOL_GPL(component_aggregate_unregister);
+
 static void component_unbind(struct component *component,
 	struct aggregate_device *adev, void *data)
 {
@@ -551,6 +764,8 @@  void component_unbind_all(struct device *parent, void *data)
 			c = adev->match->compare[i].component;
 			component_unbind(c, adev, data);
 		}
+
+	put_device(&adev->dev);
 }
 EXPORT_SYMBOL_GPL(component_unbind_all);
 
@@ -645,6 +860,7 @@  int component_bind_all(struct device *parent, void *data)
 				component_unbind(c, adev, data);
 			}
 	}
+	put_device(&adev->dev);
 
 	return ret;
 }
@@ -668,18 +884,22 @@  static int __component_add(struct device *dev, const struct component_ops *ops,
 
 	mutex_lock(&component_mutex);
 	list_add_tail(&component->node, &component_list);
-
-	ret = try_to_bring_up_masters(component);
-	if (ret < 0) {
-		if (component->adev)
-			remove_component(component->adev, component);
-		list_del(&component->node);
-
-		kfree(component);
-	}
 	mutex_unlock(&component_mutex);
 
-	return ret < 0 ? ret : 0;
+	/*
+	 * Try to bind.
+	 *
+	 * Note: we don't check the return value here because component devices
+	 * don't care that the aggregate device can actually probe or not. They
+	 * only care about adding themselves to the component_list and then
+	 * waiting for their component_ops::bind_component callback to be
+	 * called.
+	 */
+	ret = bus_rescan_devices(&aggregate_bus_type);
+	if (ret)
+		dev_dbg(dev, "rescan returned %d\n", ret);
+
+	return 0;
 }
 
 /**
@@ -743,6 +963,7 @@  EXPORT_SYMBOL_GPL(component_add);
  */
 void component_del(struct device *dev, const struct component_ops *ops)
 {
+	struct aggregate_device *adev = NULL;
 	struct component *c, *component = NULL;
 
 	mutex_lock(&component_mutex);
@@ -754,13 +975,26 @@  void component_del(struct device *dev, const struct component_ops *ops)
 		}
 
 	if (component && component->adev) {
-		take_down_aggregate_device(component->adev);
-		remove_component(component->adev, component);
+		adev = component->adev;
+		remove_component(adev, component);
 	}
 
 	mutex_unlock(&component_mutex);
 
+	if (adev) {
+		/* Force unbind */
+		device_driver_detach(&adev->dev);
+		device_link_del(component->link);
+		put_device(&adev->dev);
+	}
+
 	WARN_ON(!component);
 	kfree(component);
 }
 EXPORT_SYMBOL_GPL(component_del);
+
+static int __init aggregate_bus_init(void)
+{
+	return bus_register(&aggregate_bus_type);
+}
+postcore_initcall(aggregate_bus_init);
diff --git a/include/linux/component.h b/include/linux/component.h
index 7012569c6546..aa69ea0401d3 100644
--- a/include/linux/component.h
+++ b/include/linux/component.h
@@ -3,7 +3,8 @@ 
 #define COMPONENT_H
 
 #include <linux/stddef.h>
-
+#include <linux/device/driver.h>
+#include <linux/refcount.h>
 
 struct device;
 
@@ -82,11 +83,66 @@  struct component_master_ops {
 	void (*unbind)(struct device *master);
 };
 
+/**
+ * struct aggregate_driver - Aggregate driver (made up of other drivers)
+ * @count: driver registration refcount
+ * @driver: device driver
+ */
+struct aggregate_driver {
+	/**
+	 * @probe:
+	 *
+	 * Called when all components or the aggregate driver, as specified in
+	 * the aggregate_device's match list are
+	 * ready. Usually there are 3 steps to bind an aggregate driver:
+	 *
+	 * 1. Allocate a struct aggregate_driver.
+	 *
+	 * 2. Bind all components to the aggregate driver by calling
+	 *    component_bind_all() with the aggregate driver structure as opaque
+	 *    pointer data.
+	 *
+	 * 3. Register the aggregate driver with the subsystem to publish its
+	 *    interfaces.
+	 */
+	int (*probe)(struct aggregate_device *adev);
+	/**
+	 * @remove:
+	 *
+	 * Called when either the aggregate driver, using
+	 * component_aggregate_unregister(), or one of its components, using
+	 * component_del(), is unregistered.
+	 */
+	void (*remove)(struct aggregate_device *adev);
+	/**
+	 * @shutdown:
+	 *
+	 * Called when the system is shutting down.
+	 */
+	void (*shutdown)(struct aggregate_device *adev);
+
+	refcount_t		count;
+	struct device_driver	driver;
+};
+
+static inline struct aggregate_driver *to_aggregate_driver(struct device_driver *d)
+{
+	if (!d)
+		return NULL;
+
+	return container_of(d, struct aggregate_driver, driver);
+}
+
 void component_master_del(struct device *,
 	const struct component_master_ops *);
 
 struct component_match;
 
+int component_aggregate_register(struct device *parent,
+	struct aggregate_driver *adrv, struct component_match *match);
+void component_aggregate_unregister(struct device *parent,
+	struct aggregate_driver *adrv);
+
 int component_master_add_with_match(struct device *,
 	const struct component_master_ops *, struct component_match *);
 void component_match_add_release(struct device *parent,