1 files changed, 276 insertions, 51 deletions

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index a5cde94bb98..e4ffbcf2f51 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -11,43 +11,220 @@
  *
  * Copyright (c) 2002-5 Patrick Mochel
  * Copyright (c) 2002-3 Open Source Development Labs
- * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
- * Copyright (c) 2007 Novell Inc.
+ * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
+ * Copyright (c) 2007-2009 Novell Inc.
  *
  * This file is released under the GPLv2
  */
 
 #include <linux/device.h>
+#include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include <linux/wait.h>
+#include <linux/async.h>
+#include <linux/pm_runtime.h>
+#include <linux/pinctrl/devinfo.h>
 
 #include "base.h"
 #include "power/power.h"
 
+/*
+ * Deferred Probe infrastructure.
+ *
+ * Sometimes driver probe order matters, but the kernel doesn't always have
+ * dependency information which means some drivers will get probed before a
+ * resource it depends on is available.  For example, an SDHCI driver may
+ * first need a GPIO line from an i2c GPIO controller before it can be
+ * initialized.  If a required resource is not available yet, a driver can
+ * request probing to be deferred by returning -EPROBE_DEFER from its probe hook
+ *
+ * Deferred probe maintains two lists of devices, a pending list and an active
+ * list.  A driver returning -EPROBE_DEFER causes the device to be added to the
+ * pending list.  A successful driver probe will trigger moving all devices
+ * from the pending to the active list so that the workqueue will eventually
+ * retry them.
+ *
+ * The deferred_probe_mutex must be held any time the deferred_probe_*_list
+ * of the (struct device*)->p->deferred_probe pointers are manipulated
+ */
+static DEFINE_MUTEX(deferred_probe_mutex);
+static LIST_HEAD(deferred_probe_pending_list);
+static LIST_HEAD(deferred_probe_active_list);
+static struct workqueue_struct *deferred_wq;
+static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
+
+/**
+ * deferred_probe_work_func() - Retry probing devices in the active list.
+ */
+static void deferred_probe_work_func(struct work_struct *work)
+{
+	struct device *dev;
+	struct device_private *private;
+	/*
+	 * This block processes every device in the deferred 'active' list.
+	 * Each device is removed from the active list and passed to
+	 * bus_probe_device() to re-attempt the probe.  The loop continues
+	 * until every device in the active list is removed and retried.
+	 *
+	 * Note: Once the device is removed from the list and the mutex is
+	 * released, it is possible for the device get freed by another thread
+	 * and cause a illegal pointer dereference.  This code uses
+	 * get/put_device() to ensure the device structure cannot disappear
+	 * from under our feet.
+	 */
+	mutex_lock(&deferred_probe_mutex);
+	while (!list_empty(&deferred_probe_active_list)) {
+		private = list_first_entry(&deferred_probe_active_list,
+					typeof(*dev->p), deferred_probe);
+		dev = private->device;
+		list_del_init(&private->deferred_probe);
+
+		get_device(dev);
+
+		/*
+		 * Drop the mutex while probing each device; the probe path may
+		 * manipulate the deferred list
+		 */
+		mutex_unlock(&deferred_probe_mutex);
+
+		/*
+		 * Force the device to the end of the dpm_list since
+		 * the PM code assumes that the order we add things to
+		 * the list is a good order for suspend but deferred
+		 * probe makes that very unsafe.
+		 */
+		device_pm_lock();
+		device_pm_move_last(dev);
+		device_pm_unlock();
+
+		dev_dbg(dev, "Retrying from deferred list\n");
+		bus_probe_device(dev);
+
+		mutex_lock(&deferred_probe_mutex);
+
+		put_device(dev);
+	}
+	mutex_unlock(&deferred_probe_mutex);
+}
+static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
+
+static void driver_deferred_probe_add(struct device *dev)
+{
+	mutex_lock(&deferred_probe_mutex);
+	if (list_empty(&dev->p->deferred_probe)) {
+		dev_dbg(dev, "Added to deferred list\n");
+		list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
+	}
+	mutex_unlock(&deferred_probe_mutex);
+}
+
+void driver_deferred_probe_del(struct device *dev)
+{
+	mutex_lock(&deferred_probe_mutex);
+	if (!list_empty(&dev->p->deferred_probe)) {
+		dev_dbg(dev, "Removed from deferred list\n");
+		list_del_init(&dev->p->deferred_probe);
+	}
+	mutex_unlock(&deferred_probe_mutex);
+}
+
+static bool driver_deferred_probe_enable = false;
+/**
+ * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
+ *
+ * This functions moves all devices from the pending list to the active
+ * list and schedules the deferred probe workqueue to process them.  It
+ * should be called anytime a driver is successfully bound to a device.
+ *
+ * Note, there is a race condition in multi-threaded probe. In the case where
+ * more than one device is probing at the same time, it is possible for one
+ * probe to complete successfully while another is about to defer. If the second
+ * depends on the first, then it will get put on the pending list after the
+ * trigger event has already occured and will be stuck there.
+ *
+ * The atomic 'deferred_trigger_count' is used to determine if a successful
+ * trigger has occurred in the midst of probing a driver. If the trigger count
+ * changes in the midst of a probe, then deferred processing should be triggered
+ * again.
+ */
+static void driver_deferred_probe_trigger(void)
+{
+	if (!driver_deferred_probe_enable)
+		return;
+
+	/*
+	 * A successful probe means that all the devices in the pending list
+	 * should be triggered to be reprobed.  Move all the deferred devices
+	 * into the active list so they can be retried by the workqueue
+	 */
+	mutex_lock(&deferred_probe_mutex);
+	atomic_inc(&deferred_trigger_count);
+	list_splice_tail_init(&deferred_probe_pending_list,
+			      &deferred_probe_active_list);
+	mutex_unlock(&deferred_probe_mutex);
+
+	/*
+	 * Kick the re-probe thread.  It may already be scheduled, but it is
+	 * safe to kick it again.
+	 */
+	queue_work(deferred_wq, &deferred_probe_work);
+}
+
+/**
+ * deferred_probe_initcall() - Enable probing of deferred devices
+ *
+ * We don't want to get in the way when the bulk of drivers are getting probed.
+ * Instead, this initcall makes sure that deferred probing is delayed until
+ * late_initcall time.
+ */
+static int deferred_probe_initcall(void)
+{
+	deferred_wq = create_singlethread_workqueue("deferwq");
+	if (WARN_ON(!deferred_wq))
+		return -ENOMEM;
+
+	driver_deferred_probe_enable = true;
+	driver_deferred_probe_trigger();
+	/* Sort as many dependencies as possible before exiting initcalls */
+	flush_workqueue(deferred_wq);
+	return 0;
+}
+late_initcall(deferred_probe_initcall);
 
 static void driver_bound(struct device *dev)
 {
-	if (klist_node_attached(&dev->knode_driver)) {
+	if (klist_node_attached(&dev->p->knode_driver)) {
 		printk(KERN_WARNING "%s: device %s already bound\n",
-			__FUNCTION__, kobject_name(&dev->kobj));
+			__func__, kobject_name(&dev->kobj));
 		return;
 	}
 
-	pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->bus_id,
-		 __FUNCTION__, dev->driver->name);
+	pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name,
+		 __func__, dev_name(dev));
+
+	klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
+
+	/*
+	 * Make sure the device is no longer in one of the deferred lists and
+	 * kick off retrying all pending devices
+	 */
+	driver_deferred_probe_del(dev);
+	driver_deferred_probe_trigger();
 
 	if (dev->bus)
 		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 					     BUS_NOTIFY_BOUND_DRIVER, dev);
-
-	klist_add_tail(&dev->knode_driver, &dev->driver->p->klist_devices);
 }
 
 static int driver_sysfs_add(struct device *dev)
 {
 	int ret;
 
+	if (dev->bus)
+		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
+					     BUS_NOTIFY_BIND_DRIVER, dev);
+
 	ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
 			  kobject_name(&dev->kobj));
 	if (ret == 0) {
@@ -82,7 +259,7 @@ static void driver_sysfs_remove(struct device *dev)
  * for before calling this. (It is ok to call with no other effort
  * from a driver's probe() method.)
  *
- * This function must be called with @dev->sem held.
+ * This function must be called with the device lock held.
  */
 int device_bind_driver(struct device *dev)
 {
@@ -101,16 +278,23 @@ static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
 static int really_probe(struct device *dev, struct device_driver *drv)
 {
 	int ret = 0;
+	int local_trigger_count = atomic_read(&deferred_trigger_count);
 
 	atomic_inc(&probe_count);
 	pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
-		 drv->bus->name, __FUNCTION__, drv->name, dev->bus_id);
+		 drv->bus->name, __func__, drv->name, dev_name(dev));
 	WARN_ON(!list_empty(&dev->devres_head));
 
 	dev->driver = drv;
+
+	/* If using pinctrl, bind pins now before probing */
+	ret = pinctrl_bind_pins(dev);
+	if (ret)
+		goto probe_failed;
+
 	if (driver_sysfs_add(dev)) {
 		printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
-			__FUNCTION__, dev->bus_id);
+			__func__, dev_name(dev));
 		goto probe_failed;
 	}
 
@@ -127,19 +311,30 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 	driver_bound(dev);
 	ret = 1;
 	pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
-		 drv->bus->name, __FUNCTION__, dev->bus_id, drv->name);
+		 drv->bus->name, __func__, dev_name(dev), drv->name);
 	goto done;
 
 probe_failed:
 	devres_release_all(dev);
 	driver_sysfs_remove(dev);
 	dev->driver = NULL;
-
-	if (ret != -ENODEV && ret != -ENXIO) {
+	dev_set_drvdata(dev, NULL);
+
+	if (ret == -EPROBE_DEFER) {
+		/* Driver requested deferred probing */
+		dev_info(dev, "Driver %s requests probe deferral\n", drv->name);
+		driver_deferred_probe_add(dev);
+		/* Did a trigger occur while probing? Need to re-trigger if yes */
+		if (local_trigger_count != atomic_read(&deferred_trigger_count))
+			driver_deferred_probe_trigger();
+	} else if (ret != -ENODEV && ret != -ENXIO) {
 		/* driver matched but the probe failed */
 		printk(KERN_WARNING
 		       "%s: probe of %s failed with error %d\n",
-		       drv->name, dev->bus_id, ret);
+		       drv->name, dev_name(dev), ret);
+	} else {
+		pr_debug("%s: probe of %s rejects match %d\n",
+		       drv->name, dev_name(dev), ret);
 	}
 	/*
 	 * Ignore errors returned by ->probe so that the next driver can try
@@ -160,7 +355,7 @@ done:
  */
 int driver_probe_done(void)
 {
-	pr_debug("%s: probe_count = %d\n", __FUNCTION__,
+	pr_debug("%s: probe_count = %d\n", __func__,
 		 atomic_read(&probe_count));
 	if (atomic_read(&probe_count))
 		return -EBUSY;
@@ -168,21 +363,27 @@ int driver_probe_done(void)
 }
 
 /**
+ * wait_for_device_probe
+ * Wait for device probing to be completed.
+ */
+void wait_for_device_probe(void)
+{
+	/* wait for the known devices to complete their probing */
+	wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
+	async_synchronize_full();
+}
+EXPORT_SYMBOL_GPL(wait_for_device_probe);
+
+/**
  * driver_probe_device - attempt to bind device & driver together
  * @drv: driver to bind a device to
  * @dev: device to try to bind to the driver
  *
- * First, we call the bus's match function, if one present, which should
- * compare the device IDs the driver supports with the device IDs of the
- * device. Note we don't do this ourselves because we don't know the
- * format of the ID structures, nor what is to be considered a match and
- * what is not.
- *
- * This function returns 1 if a match is found, -ENODEV if the device is
- * not registered, and 0 otherwise.
+ * This function returns -ENODEV if the device is not registered,
+ * 1 if the device is bound successfully and 0 otherwise.
  *
- * This function must be called with @dev->sem held.  When called for a
- * USB interface, @dev->parent->sem must be held as well.
+ * This function must be called with @dev lock held.  When called for a
+ * USB interface, @dev->parent lock must be held as well.
  */
 int driver_probe_device(struct device_driver *drv, struct device *dev)
 {
@@ -190,21 +391,24 @@ int driver_probe_device(struct device_driver *drv, struct device *dev)
 
 	if (!device_is_registered(dev))
 		return -ENODEV;
-	if (drv->bus->match && !drv->bus->match(dev, drv))
-		goto done;
 
 	pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
-		 drv->bus->name, __FUNCTION__, dev->bus_id, drv->name);
+		 drv->bus->name, __func__, dev_name(dev), drv->name);
 
+	pm_runtime_barrier(dev);
 	ret = really_probe(dev, drv);
+	pm_request_idle(dev);
 
-done:
 	return ret;
 }
 
 static int __device_attach(struct device_driver *drv, void *data)
 {
 	struct device *dev = data;
+
+	if (!driver_match_device(drv, dev))
+		return 0;
+
 	return driver_probe_device(drv, dev);
 }
 
@@ -217,17 +421,21 @@ static int __device_attach(struct device_driver *drv, void *data)
  * pair is found, break out and return.
  *
  * Returns 1 if the device was bound to a driver;
- * 0 if no matching device was found;
+ * 0 if no matching driver was found;
  * -ENODEV if the device is not registered.
  *
- * When called for a USB interface, @dev->parent->sem must be held.
+ * When called for a USB interface, @dev->parent lock must be held.
  */
 int device_attach(struct device *dev)
 {
 	int ret = 0;
 
-	down(&dev->sem);
+	device_lock(dev);
 	if (dev->driver) {
+		if (klist_node_attached(&dev->p->knode_driver)) {
+			ret = 1;
+			goto out_unlock;
+		}
 		ret = device_bind_driver(dev);
 		if (ret == 0)
 			ret = 1;
@@ -237,8 +445,10 @@ int device_attach(struct device *dev)
 		}
 	} else {
 		ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
+		pm_request_idle(dev);
 	}
-	up(&dev->sem);
+out_unlock:
+	device_unlock(dev);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(device_attach);
@@ -257,14 +467,17 @@ static int __driver_attach(struct device *dev, void *data)
 	 * is an error.
 	 */
 
+	if (!driver_match_device(drv, dev))
+		return 0;
+
 	if (dev->parent)	/* Needed for USB */
-		down(&dev->parent->sem);
-	down(&dev->sem);
+		device_lock(dev->parent);
+	device_lock(dev);
 	if (!dev->driver)
 		driver_probe_device(drv, dev);
-	up(&dev->sem);
+	device_unlock(dev);
 	if (dev->parent)
-		up(&dev->parent->sem);
+		device_unlock(dev->parent);
 
 	return 0;
 }
@@ -285,8 +498,8 @@ int driver_attach(struct device_driver *drv)
 EXPORT_SYMBOL_GPL(driver_attach);
 
 /*
- * __device_release_driver() must be called with @dev->sem held.
- * When called for a USB interface, @dev->parent->sem must be held as well.
+ * __device_release_driver() must be called with @dev lock held.
+ * When called for a USB interface, @dev->parent lock must be held as well.
  */
 static void __device_release_driver(struct device *dev)
 {
@@ -294,21 +507,30 @@ static void __device_release_driver(struct device *dev)
 
 	drv = dev->driver;
 	if (drv) {
+		pm_runtime_get_sync(dev);
+
 		driver_sysfs_remove(dev);
-		sysfs_remove_link(&dev->kobj, "driver");
 
 		if (dev->bus)
 			blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 						     BUS_NOTIFY_UNBIND_DRIVER,
 						     dev);
 
+		pm_runtime_put_sync(dev);
+
 		if (dev->bus && dev->bus->remove)
 			dev->bus->remove(dev);
 		else if (drv->remove)
 			drv->remove(dev);
 		devres_release_all(dev);
 		dev->driver = NULL;
-		klist_remove(&dev->knode_driver);
+		dev_set_drvdata(dev, NULL);
+		klist_remove(&dev->p->knode_driver);
+		if (dev->bus)
+			blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
+						     BUS_NOTIFY_UNBOUND_DRIVER,
+						     dev);
+
 	}
 }
 
@@ -317,7 +539,7 @@ static void __device_release_driver(struct device *dev)
  * @dev: device.
  *
  * Manually detach device from driver.
- * When called for a USB interface, @dev->parent->sem must be held.
+ * When called for a USB interface, @dev->parent lock must be held.
  */
 void device_release_driver(struct device *dev)
 {
@@ -326,9 +548,9 @@ void device_release_driver(struct device *dev)
 	 * within their ->remove callback for the same device, they
 	 * will deadlock right here.
 	 */
-	down(&dev->sem);
+	device_lock(dev);
 	__device_release_driver(dev);
-	up(&dev->sem);
+	device_unlock(dev);
 }
 EXPORT_SYMBOL_GPL(device_release_driver);
 
@@ -338,6 +560,7 @@ EXPORT_SYMBOL_GPL(device_release_driver);
  */
 void driver_detach(struct device_driver *drv)
 {
+	struct device_private *dev_prv;
 	struct device *dev;
 
 	for (;;) {
@@ -346,19 +569,21 @@ void driver_detach(struct device_driver *drv)
 			spin_unlock(&drv->p->klist_devices.k_lock);
 			break;
 		}
-		dev = list_entry(drv->p->klist_devices.k_list.prev,
-				struct device, knode_driver.n_node);
+		dev_prv = list_entry(drv->p->klist_devices.k_list.prev,
+				     struct device_private,
+				     knode_driver.n_node);
+		dev = dev_prv->device;
 		get_device(dev);
 		spin_unlock(&drv->p->klist_devices.k_lock);
 
 		if (dev->parent)	/* Needed for USB */
-			down(&dev->parent->sem);
-		down(&dev->sem);
+			device_lock(dev->parent);
+		device_lock(dev);
 		if (dev->driver == drv)
 			__device_release_driver(dev);
-		up(&dev->sem);
+		device_unlock(dev);
 		if (dev->parent)
-			up(&dev->parent->sem);
+			device_unlock(dev->parent);
 		put_device(dev);
 	}
 }