driver core: move the deferred probe pointer into the private area
[linux-2.6.git] / drivers / base / dd.c
index 20febc0..9fa888e 100644 (file)
  *
  * 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 "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;
+
+/**
+ * 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);
+               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(&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.
+ */
+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);
+       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();
+       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",
                        __func__, kobject_name(&dev->kobj));
                return;
        }
 
-       pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->bus_id,
+       pr_debug("driver: '%s': %s: bound to device '%s'\n", dev_name(dev),
                 __func__, dev->driver->name);
 
+       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 +223,7 @@ 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)
 {
@@ -104,13 +245,13 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 
        atomic_inc(&probe_count);
        pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
-                drv->bus->name, __func__, 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 (driver_sysfs_add(dev)) {
                printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
-                       __func__, dev->bus_id);
+                       __func__, dev_name(dev));
                goto probe_failed;
        }
 
@@ -127,7 +268,7 @@ 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, __func__, dev->bus_id, drv->name);
+                drv->bus->name, __func__, dev_name(dev), drv->name);
        goto done;
 
 probe_failed:
@@ -135,11 +276,18 @@ probe_failed:
        driver_sysfs_remove(dev);
        dev->driver = NULL;
 
-       if (ret != -ENODEV && ret != -ENXIO) {
+       if (ret == -EPROBE_DEFER) {
+               /* Driver requested deferred probing */
+               dev_info(dev, "Driver %s requests probe deferral\n", drv->name);
+               driver_deferred_probe_add(dev);
+       } 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
@@ -168,21 +316,27 @@ 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 -ENODEV if the device is not registered,
+ * 1 if the device is bound successfully and 0 otherwise.
  *
- * This function returns 1 if a match is found, -ENODEV if the device is
- * not registered, 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 +344,25 @@ 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, __func__, dev->bus_id, drv->name);
+                drv->bus->name, __func__, dev_name(dev), drv->name);
 
+       pm_runtime_get_noresume(dev);
+       pm_runtime_barrier(dev);
        ret = really_probe(dev, drv);
+       pm_runtime_put_sync(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 +375,21 @@ 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;
@@ -236,9 +398,12 @@ int device_attach(struct device *dev)
                        ret = 0;
                }
        } else {
+               pm_runtime_get_noresume(dev);
                ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
+               pm_runtime_put_sync(dev);
        }
-       up(&dev->sem);
+out_unlock:
+       device_unlock(dev);
        return ret;
 }
 EXPORT_SYMBOL_GPL(device_attach);
@@ -257,17 +422,17 @@ static int __driver_attach(struct device *dev, void *data)
         * is an error.
         */
 
-       if (drv->bus->match && !drv->bus->match(dev, drv))
+       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;
 }
@@ -288,8 +453,8 @@ 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)
 {
@@ -297,21 +462,29 @@ 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);
+               klist_remove(&dev->p->knode_driver);
+               if (dev->bus)
+                       blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
+                                                    BUS_NOTIFY_UNBOUND_DRIVER,
+                                                    dev);
+
        }
 }
 
@@ -320,7 +493,7 @@ 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)
 {
@@ -329,9 +502,9 @@ 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);
 
@@ -341,6 +514,7 @@ EXPORT_SYMBOL_GPL(device_release_driver);
  */
 void driver_detach(struct device_driver *drv)
 {
+       struct device_private *dev_prv;
        struct device *dev;
 
        for (;;) {
@@ -349,19 +523,47 @@ 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);
        }
 }
+
+/*
+ * These exports can't be _GPL due to .h files using this within them, and it
+ * might break something that was previously working...
+ */
+void *dev_get_drvdata(const struct device *dev)
+{
+       if (dev && dev->p)
+               return dev->p->driver_data;
+       return NULL;
+}
+EXPORT_SYMBOL(dev_get_drvdata);
+
+int dev_set_drvdata(struct device *dev, void *data)
+{
+       int error;
+
+       if (!dev->p) {
+               error = device_private_init(dev);
+               if (error)
+                       return error;
+       }
+       dev->p->driver_data = data;
+       return 0;
+}
+EXPORT_SYMBOL(dev_set_drvdata);