/*
- * drivers/base/dd.c - The core device/driver interactions.
+ * drivers/base/dd.c - The core device/driver interactions.
*
- * This file contains the (sometimes tricky) code that controls the
- * interactions between devices and drivers, which primarily includes
- * driver binding and unbinding.
+ * This file contains the (sometimes tricky) code that controls the
+ * interactions between devices and drivers, which primarily includes
+ * driver binding and unbinding.
*
- * All of this code used to exist in drivers/base/bus.c, but was
- * relocated to here in the name of compartmentalization (since it wasn't
- * strictly code just for the 'struct bus_type'.
+ * All of this code used to exist in drivers/base/bus.c, but was
+ * relocated to here in the name of compartmentalization (since it wasn't
+ * strictly code just for the 'struct bus_type'.
*
- * Copyright (c) 2002-5 Patrick Mochel
- * Copyright (c) 2002-3 Open Source Development Labs
+ * 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.
*
- * This file is released under the GPLv2
+ * This file is released under the GPLv2
*/
#include <linux/device.h>
#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/wait.h>
#include "base.h"
#include "power/power.h"
-#define to_drv(node) container_of(node, struct device_driver, kobj.entry)
+static void driver_bound(struct device *dev)
+{
+ if (klist_node_attached(&dev->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,
+ __func__, dev->driver->name);
+
+ 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;
+
+ ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
+ kobject_name(&dev->kobj));
+ if (ret == 0) {
+ ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
+ "driver");
+ if (ret)
+ sysfs_remove_link(&dev->driver->p->kobj,
+ kobject_name(&dev->kobj));
+ }
+ return ret;
+}
+
+static void driver_sysfs_remove(struct device *dev)
+{
+ struct device_driver *drv = dev->driver;
+
+ if (drv) {
+ sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
+ sysfs_remove_link(&dev->kobj, "driver");
+ }
+}
/**
- * device_bind_driver - bind a driver to one device.
- * @dev: device.
+ * device_bind_driver - bind a driver to one device.
+ * @dev: device.
*
- * Allow manual attachment of a driver to a device.
- * Caller must have already set @dev->driver.
+ * Allow manual attachment of a driver to a device.
+ * Caller must have already set @dev->driver.
*
- * Note that this does not modify the bus reference count
- * nor take the bus's rwsem. Please verify those are accounted
- * for before calling this. (It is ok to call with no other effort
- * from a driver's probe() method.)
+ * Note that this does not modify the bus reference count
+ * nor take the bus's rwsem. Please verify those are accounted
+ * 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.
*/
-void device_bind_driver(struct device * dev)
+int device_bind_driver(struct device *dev)
{
- pr_debug("bound device '%s' to driver '%s'\n",
- dev->bus_id, dev->driver->name);
- klist_add_tail(&dev->driver->klist_devices, &dev->knode_driver);
- sysfs_create_link(&dev->driver->kobj, &dev->kobj,
- kobject_name(&dev->kobj));
- sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver");
+ int ret;
+
+ ret = driver_sysfs_add(dev);
+ if (!ret)
+ driver_bound(dev);
+ return ret;
}
+EXPORT_SYMBOL_GPL(device_bind_driver);
-/**
- * driver_probe_device - attempt to bind device & driver.
- * @drv: driver.
- * @dev: device.
- *
- * 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.
- *
- * If we find a match, we call @drv->probe(@dev) if it exists, and
- * call device_bind_driver() above.
- */
-int driver_probe_device(struct device_driver * drv, struct device * dev)
+static atomic_t probe_count = ATOMIC_INIT(0);
+static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
+
+static int really_probe(struct device *dev, struct device_driver *drv)
{
- int error = 0;
+ int ret = 0;
- if (drv->bus->match && !drv->bus->match(dev, drv))
- return -ENODEV;
+ 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);
+ WARN_ON(!list_empty(&dev->devres_head));
- down(&dev->sem);
dev->driver = drv;
- if (drv->probe) {
- error = drv->probe(dev);
- if (error) {
- dev->driver = NULL;
- up(&dev->sem);
- return error;
- }
+ if (driver_sysfs_add(dev)) {
+ printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
+ __func__, dev->bus_id);
+ goto probe_failed;
}
- up(&dev->sem);
- device_bind_driver(dev);
- return 0;
-}
-static int __device_attach(struct device_driver * drv, void * data)
-{
- struct device * dev = data;
- int error;
+ if (dev->bus->probe) {
+ ret = dev->bus->probe(dev);
+ if (ret)
+ goto probe_failed;
+ } else if (drv->probe) {
+ ret = drv->probe(dev);
+ if (ret)
+ goto probe_failed;
+ }
- error = driver_probe_device(drv, dev);
+ 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);
+ goto done;
- if (error == -ENODEV && error == -ENXIO) {
- /* Driver matched, but didn't support device
- * or device not found.
- * Not an error; keep going.
- */
- error = 0;
- } else {
+probe_failed:
+ devres_release_all(dev);
+ driver_sysfs_remove(dev);
+ dev->driver = NULL;
+
+ 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, error);
+ drv->name, dev->bus_id, ret);
}
+ /*
+ * Ignore errors returned by ->probe so that the next driver can try
+ * its luck.
+ */
+ ret = 0;
+done:
+ atomic_dec(&probe_count);
+ wake_up(&probe_waitqueue);
+ return ret;
+}
+
+/**
+ * driver_probe_done
+ * Determine if the probe sequence is finished or not.
+ *
+ * Should somehow figure out how to use a semaphore, not an atomic variable...
+ */
+int driver_probe_done(void)
+{
+ pr_debug("%s: probe_count = %d\n", __func__,
+ atomic_read(&probe_count));
+ if (atomic_read(&probe_count))
+ return -EBUSY;
return 0;
}
/**
- * device_attach - try to attach device to a driver.
- * @dev: device.
+ * 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
*
- * Walk the list of drivers that the bus has and call
- * driver_probe_device() for each pair. If a compatible
- * pair is found, break out and return.
+ * 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 must be called with @dev->sem held. When called for a
+ * USB interface, @dev->parent->sem must be held as well.
*/
-int device_attach(struct device * dev)
+int driver_probe_device(struct device_driver *drv, struct device *dev)
{
- if (dev->driver) {
- device_bind_driver(dev);
- return 1;
- }
+ int ret = 0;
+
+ 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);
+
+ ret = really_probe(dev, drv);
- return bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
+done:
+ return ret;
}
-static int __driver_attach(struct device * dev, void * data)
+static int __device_attach(struct device_driver *drv, void *data)
{
- struct device_driver * drv = data;
- int error = 0;
-
- if (!dev->driver) {
- error = driver_probe_device(drv, dev);
- if (error) {
- if (error != -ENODEV) {
- /* driver matched but the probe failed */
- printk(KERN_WARNING
- "%s: probe of %s failed with error %d\n",
- drv->name, dev->bus_id, error);
- } else
- error = 0;
- }
- }
- return 0;
+ struct device *dev = data;
+ return driver_probe_device(drv, dev);
}
/**
- * driver_attach - try to bind driver to devices.
- * @drv: driver.
+ * device_attach - try to attach device to a driver.
+ * @dev: device.
+ *
+ * Walk the list of drivers that the bus has and call
+ * driver_probe_device() for each pair. If a compatible
+ * pair is found, break out and return.
*
- * Walk the list of devices that the bus has on it and try to
- * match the driver with each one. If driver_probe_device()
- * returns 0 and the @dev->driver is set, we've found a
- * compatible pair.
+ * Returns 1 if the device was bound to a driver;
+ * 0 if no matching device was found;
+ * -ENODEV if the device is not registered.
*
- * Note that we ignore the -ENODEV error from driver_probe_device(),
- * since it's perfectly valid for a driver not to bind to any devices.
+ * When called for a USB interface, @dev->parent->sem must be held.
*/
-void driver_attach(struct device_driver * drv)
+int device_attach(struct device *dev)
{
- bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
+ int ret = 0;
+
+ down(&dev->sem);
+ if (dev->driver) {
+ ret = device_bind_driver(dev);
+ if (ret == 0)
+ ret = 1;
+ else {
+ dev->driver = NULL;
+ ret = 0;
+ }
+ } else {
+ ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
+ }
+ up(&dev->sem);
+ return ret;
}
+EXPORT_SYMBOL_GPL(device_attach);
-/**
- * device_release_driver - manually detach device from driver.
- * @dev: device.
- *
- * Manually detach device from driver.
- * Note that this is called without incrementing the bus
- * reference count nor taking the bus's rwsem. Be sure that
- * those are accounted for before calling this function.
- */
-void device_release_driver(struct device * dev)
+static int __driver_attach(struct device *dev, void *data)
{
- struct device_driver * drv = dev->driver;
+ struct device_driver *drv = data;
- if (!drv)
- return;
+ /*
+ * Lock device and try to bind to it. We drop the error
+ * here and always return 0, because we need to keep trying
+ * to bind to devices and some drivers will return an error
+ * simply if it didn't support the device.
+ *
+ * driver_probe_device() will spit a warning if there
+ * is an error.
+ */
- sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
- sysfs_remove_link(&dev->kobj, "driver");
- klist_remove(&dev->knode_driver);
+ if (drv->bus->match && !drv->bus->match(dev, drv))
+ return 0;
+ if (dev->parent) /* Needed for USB */
+ down(&dev->parent->sem);
down(&dev->sem);
- if (drv->remove)
- drv->remove(dev);
- dev->driver = NULL;
+ if (!dev->driver)
+ driver_probe_device(drv, dev);
up(&dev->sem);
-}
+ if (dev->parent)
+ up(&dev->parent->sem);
-static int __remove_driver(struct device * dev, void * unused)
-{
- device_release_driver(dev);
return 0;
}
/**
- * driver_detach - detach driver from all devices it controls.
+ * driver_attach - try to bind driver to devices.
* @drv: driver.
+ *
+ * Walk the list of devices that the bus has on it and try to
+ * match the driver with each one. If driver_probe_device()
+ * returns 0 and the @dev->driver is set, we've found a
+ * compatible pair.
*/
-void driver_detach(struct device_driver * drv)
+int driver_attach(struct device_driver *drv)
{
- driver_for_each_device(drv, NULL, NULL, __remove_driver);
+ return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
}
+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.
+ */
+static void __device_release_driver(struct device *dev)
+{
+ struct device_driver *drv;
+ drv = dev->driver;
+ if (drv) {
+ driver_sysfs_remove(dev);
+ sysfs_remove_link(&dev->kobj, "driver");
-EXPORT_SYMBOL_GPL(driver_probe_device);
-EXPORT_SYMBOL_GPL(device_bind_driver);
+ if (dev->bus)
+ blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
+ BUS_NOTIFY_UNBIND_DRIVER,
+ 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);
+ }
+}
+
+/**
+ * device_release_driver - manually detach device from driver.
+ * @dev: device.
+ *
+ * Manually detach device from driver.
+ * When called for a USB interface, @dev->parent->sem must be held.
+ */
+void device_release_driver(struct device *dev)
+{
+ /*
+ * If anyone calls device_release_driver() recursively from
+ * within their ->remove callback for the same device, they
+ * will deadlock right here.
+ */
+ down(&dev->sem);
+ __device_release_driver(dev);
+ up(&dev->sem);
+}
EXPORT_SYMBOL_GPL(device_release_driver);
-EXPORT_SYMBOL_GPL(device_attach);
-EXPORT_SYMBOL_GPL(driver_attach);
+/**
+ * driver_detach - detach driver from all devices it controls.
+ * @drv: driver.
+ */
+void driver_detach(struct device_driver *drv)
+{
+ struct device *dev;
+
+ for (;;) {
+ spin_lock(&drv->p->klist_devices.k_lock);
+ if (list_empty(&drv->p->klist_devices.k_list)) {
+ 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);
+ get_device(dev);
+ spin_unlock(&drv->p->klist_devices.k_lock);
+
+ if (dev->parent) /* Needed for USB */
+ down(&dev->parent->sem);
+ down(&dev->sem);
+ if (dev->driver == drv)
+ __device_release_driver(dev);
+ up(&dev->sem);
+ if (dev->parent)
+ up(&dev->parent->sem);
+ put_device(dev);
+ }
+}