2 * drivers/base/dd.c - The core device/driver interactions.
4 * This file contains the (sometimes tricky) code that controls the
5 * interactions between devices and drivers, which primarily includes
6 * driver binding and unbinding.
8 * All of this code used to exist in drivers/base/bus.c, but was
9 * relocated to here in the name of compartmentalization (since it wasn't
10 * strictly code just for the 'struct bus_type'.
12 * Copyright (c) 2002-5 Patrick Mochel
13 * Copyright (c) 2002-3 Open Source Development Labs
15 * This file is released under the GPLv2
18 #include <linux/device.h>
19 #include <linux/module.h>
20 #include <linux/kthread.h>
21 #include <linux/wait.h>
24 #include "power/power.h"
26 #define to_drv(node) container_of(node, struct device_driver, kobj.entry)
29 static void driver_bound(struct device
*dev
)
31 if (klist_node_attached(&dev
->knode_driver
)) {
32 printk(KERN_WARNING
"%s: device %s already bound\n",
33 __FUNCTION__
, kobject_name(&dev
->kobj
));
37 pr_debug("bound device '%s' to driver '%s'\n",
38 dev
->bus_id
, dev
->driver
->name
);
41 blocking_notifier_call_chain(&dev
->bus
->bus_notifier
,
42 BUS_NOTIFY_BOUND_DRIVER
, dev
);
44 klist_add_tail(&dev
->knode_driver
, &dev
->driver
->klist_devices
);
47 static int driver_sysfs_add(struct device
*dev
)
51 ret
= sysfs_create_link(&dev
->driver
->kobj
, &dev
->kobj
,
52 kobject_name(&dev
->kobj
));
54 ret
= sysfs_create_link(&dev
->kobj
, &dev
->driver
->kobj
,
57 sysfs_remove_link(&dev
->driver
->kobj
,
58 kobject_name(&dev
->kobj
));
63 static void driver_sysfs_remove(struct device
*dev
)
65 struct device_driver
*drv
= dev
->driver
;
68 sysfs_remove_link(&drv
->kobj
, kobject_name(&dev
->kobj
));
69 sysfs_remove_link(&dev
->kobj
, "driver");
74 * device_bind_driver - bind a driver to one device.
77 * Allow manual attachment of a driver to a device.
78 * Caller must have already set @dev->driver.
80 * Note that this does not modify the bus reference count
81 * nor take the bus's rwsem. Please verify those are accounted
82 * for before calling this. (It is ok to call with no other effort
83 * from a driver's probe() method.)
85 * This function must be called with @dev->sem held.
87 int device_bind_driver(struct device
*dev
)
90 return driver_sysfs_add(dev
);
93 struct stupid_thread_structure
{
94 struct device_driver
*drv
;
98 static atomic_t probe_count
= ATOMIC_INIT(0);
99 static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue
);
101 static int really_probe(void *void_data
)
103 struct stupid_thread_structure
*data
= void_data
;
104 struct device_driver
*drv
= data
->drv
;
105 struct device
*dev
= data
->dev
;
108 atomic_inc(&probe_count
);
109 pr_debug("%s: Probing driver %s with device %s\n",
110 drv
->bus
->name
, drv
->name
, dev
->bus_id
);
113 if (driver_sysfs_add(dev
)) {
114 printk(KERN_ERR
"%s: driver_sysfs_add(%s) failed\n",
115 __FUNCTION__
, dev
->bus_id
);
119 if (dev
->bus
->probe
) {
120 ret
= dev
->bus
->probe(dev
);
123 } else if (drv
->probe
) {
124 ret
= drv
->probe(dev
);
131 pr_debug("%s: Bound Device %s to Driver %s\n",
132 drv
->bus
->name
, dev
->bus_id
, drv
->name
);
136 driver_sysfs_remove(dev
);
139 if (ret
!= -ENODEV
&& ret
!= -ENXIO
) {
140 /* driver matched but the probe failed */
142 "%s: probe of %s failed with error %d\n",
143 drv
->name
, dev
->bus_id
, ret
);
146 * Ignore errors returned by ->probe so that the next driver can try
152 atomic_dec(&probe_count
);
153 wake_up(&probe_waitqueue
);
159 * Determine if the probe sequence is finished or not.
161 * Should somehow figure out how to use a semaphore, not an atomic variable...
163 int driver_probe_done(void)
165 pr_debug("%s: probe_count = %d\n", __FUNCTION__
,
166 atomic_read(&probe_count
));
167 if (atomic_read(&probe_count
))
173 * driver_probe_device - attempt to bind device & driver together
174 * @drv: driver to bind a device to
175 * @dev: device to try to bind to the driver
177 * First, we call the bus's match function, if one present, which should
178 * compare the device IDs the driver supports with the device IDs of the
179 * device. Note we don't do this ourselves because we don't know the
180 * format of the ID structures, nor what is to be considered a match and
183 * This function returns 1 if a match is found, an error if one occurs
184 * (that is not -ENODEV or -ENXIO), and 0 otherwise.
186 * This function must be called with @dev->sem held. When called for a
187 * USB interface, @dev->parent->sem must be held as well.
189 int driver_probe_device(struct device_driver
* drv
, struct device
* dev
)
191 struct stupid_thread_structure
*data
;
192 struct task_struct
*probe_task
;
195 if (!device_is_registered(dev
))
197 if (drv
->bus
->match
&& !drv
->bus
->match(dev
, drv
))
200 pr_debug("%s: Matched Device %s with Driver %s\n",
201 drv
->bus
->name
, dev
->bus_id
, drv
->name
);
203 data
= kmalloc(sizeof(*data
), GFP_KERNEL
);
209 if (drv
->multithread_probe
) {
210 probe_task
= kthread_run(really_probe
, data
,
211 "probe-%s", dev
->bus_id
);
212 if (IS_ERR(probe_task
))
213 ret
= really_probe(data
);
215 ret
= really_probe(data
);
221 static int __device_attach(struct device_driver
* drv
, void * data
)
223 struct device
* dev
= data
;
224 return driver_probe_device(drv
, dev
);
228 * device_attach - try to attach device to a driver.
231 * Walk the list of drivers that the bus has and call
232 * driver_probe_device() for each pair. If a compatible
233 * pair is found, break out and return.
235 * Returns 1 if the device was bound to a driver;
236 * 0 if no matching device was found; error code otherwise.
238 * When called for a USB interface, @dev->parent->sem must be held.
240 int device_attach(struct device
* dev
)
246 ret
= device_bind_driver(dev
);
250 ret
= bus_for_each_drv(dev
->bus
, NULL
, dev
, __device_attach
);
255 static int __driver_attach(struct device
* dev
, void * data
)
257 struct device_driver
* drv
= data
;
260 * Lock device and try to bind to it. We drop the error
261 * here and always return 0, because we need to keep trying
262 * to bind to devices and some drivers will return an error
263 * simply if it didn't support the device.
265 * driver_probe_device() will spit a warning if there
269 if (dev
->parent
) /* Needed for USB */
270 down(&dev
->parent
->sem
);
273 driver_probe_device(drv
, dev
);
276 up(&dev
->parent
->sem
);
282 * driver_attach - try to bind driver to devices.
285 * Walk the list of devices that the bus has on it and try to
286 * match the driver with each one. If driver_probe_device()
287 * returns 0 and the @dev->driver is set, we've found a
290 int driver_attach(struct device_driver
* drv
)
292 return bus_for_each_dev(drv
->bus
, NULL
, drv
, __driver_attach
);
296 * device_release_driver - manually detach device from driver.
299 * Manually detach device from driver.
301 * __device_release_driver() must be called with @dev->sem held.
302 * When called for a USB interface, @dev->parent->sem must be held
306 static void __device_release_driver(struct device
* dev
)
308 struct device_driver
* drv
;
313 driver_sysfs_remove(dev
);
314 sysfs_remove_link(&dev
->kobj
, "driver");
315 klist_remove(&dev
->knode_driver
);
318 blocking_notifier_call_chain(&dev
->bus
->bus_notifier
,
319 BUS_NOTIFY_UNBIND_DRIVER
,
322 if (dev
->bus
&& dev
->bus
->remove
)
323 dev
->bus
->remove(dev
);
324 else if (drv
->remove
)
331 void device_release_driver(struct device
* dev
)
334 * If anyone calls device_release_driver() recursively from
335 * within their ->remove callback for the same device, they
336 * will deadlock right here.
339 __device_release_driver(dev
);
345 * driver_detach - detach driver from all devices it controls.
348 void driver_detach(struct device_driver
* drv
)
353 spin_lock(&drv
->klist_devices
.k_lock
);
354 if (list_empty(&drv
->klist_devices
.k_list
)) {
355 spin_unlock(&drv
->klist_devices
.k_lock
);
358 dev
= list_entry(drv
->klist_devices
.k_list
.prev
,
359 struct device
, knode_driver
.n_node
);
361 spin_unlock(&drv
->klist_devices
.k_lock
);
363 if (dev
->parent
) /* Needed for USB */
364 down(&dev
->parent
->sem
);
366 if (dev
->driver
== drv
)
367 __device_release_driver(dev
);
370 up(&dev
->parent
->sem
);
375 #ifdef CONFIG_PCI_MULTITHREAD_PROBE
376 static int __init
wait_for_probes(void)
380 printk(KERN_INFO
"%s: waiting for %d threads\n", __FUNCTION__
,
381 atomic_read(&probe_count
));
382 if (!atomic_read(&probe_count
))
384 while (atomic_read(&probe_count
)) {
385 prepare_to_wait(&probe_waitqueue
, &wait
, TASK_UNINTERRUPTIBLE
);
386 if (atomic_read(&probe_count
))
389 finish_wait(&probe_waitqueue
, &wait
);
393 core_initcall_sync(wait_for_probes
);
394 postcore_initcall_sync(wait_for_probes
);
395 arch_initcall_sync(wait_for_probes
);
396 subsys_initcall_sync(wait_for_probes
);
397 fs_initcall_sync(wait_for_probes
);
398 device_initcall_sync(wait_for_probes
);
399 late_initcall_sync(wait_for_probes
);
402 EXPORT_SYMBOL_GPL(device_bind_driver
);
403 EXPORT_SYMBOL_GPL(device_release_driver
);
404 EXPORT_SYMBOL_GPL(device_attach
);
405 EXPORT_SYMBOL_GPL(driver_attach
);