/* *	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. * *	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 * *	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",			__FUNCTION__, kobject_name(&dev->kobj));		return;	} 	pr_debug("bound device '%s' to driver '%s'\n",		 dev->bus_id, dev->driver->name); 	if (dev->bus)		blocking_notifier_call_chain(&dev->bus->bus_notifier,					     BUS_NOTIFY_BOUND_DRIVER, dev); 	klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices);} static int driver_sysfs_add(struct device *dev){	int ret; 	ret = sysfs_create_link(&dev->driver->kobj, &dev->kobj,			  kobject_name(&dev->kobj));	if (ret == 0) {		ret = sysfs_create_link(&dev->kobj, &dev->driver->kobj,					"driver");		if (ret)			sysfs_remove_link(&dev->driver->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->kobj, kobject_name(&dev->kobj));		sysfs_remove_link(&dev->kobj, "driver");	}} /** *	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. * *	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. */int device_bind_driver(struct device *dev){	int ret; 	ret = driver_sysfs_add(dev);	if (!ret)		driver_bound(dev);	return ret;} struct stupid_thread_structure {	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(void *void_data){	struct stupid_thread_structure *data = void_data;	struct device_driver *drv = data->drv;	struct device *dev = data->dev;	int ret = 0; 	atomic_inc(&probe_count);	pr_debug("%s: Probing driver %s with device %s\n",		 drv->bus->name, drv->name, dev->bus_id);	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",			__FUNCTION__, dev->bus_id);		goto probe_failed;	} 	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;	} 	driver_bound(dev);	ret = 1;	pr_debug("%s: Bound Device %s to Driver %s\n",		 drv->bus->name, dev->bus_id, drv->name);	goto done; 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, ret);	}	/*	 * Ignore errors returned by ->probe so that the next driver can try	 * its luck.	 */	ret = 0;done:	kfree(data);	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", __FUNCTION__,		 atomic_read(&probe_count));	if (atomic_read(&probe_count))		return -EBUSY;	return 0;} /** * 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, an error if one occurs * (that is not -ENODEV or -ENXIO), 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 driver_probe_device(struct device_driver * drv, struct device * dev){	struct stupid_thread_structure *data;	struct task_struct *probe_task;	int ret = 0; 	if (!device_is_registered(dev))		return -ENODEV;	if (drv->bus->match && !drv->bus->match(dev, drv))		goto done; 	pr_debug("%s: Matched Device %s with Driver %s\n",		 drv->bus->name, dev->bus_id, drv->name); 	data = kmalloc(sizeof(*data), GFP_KERNEL);	if (!data)		return -ENOMEM;	data->drv = drv;	data->dev = dev; 	if (drv->multithread_probe) {		probe_task = kthread_run(really_probe, data,					 "probe-%s", dev->bus_id);		if (IS_ERR(probe_task))			ret = really_probe(data);	} else		ret = really_probe(data); done:	return ret;} static int __device_attach(struct device_driver * drv, void * data){	struct device * dev = data;	return driver_probe_device(drv, dev);} /** *	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. * *	Returns 1 if the device was bound to a driver; *	0 if no matching device was found; error code otherwise. * *	When called for a USB interface, @dev->parent->sem must be held. */int device_attach(struct device * dev){	int ret = 0; 	down(&dev->sem);	if (dev->driver) {		ret = device_bind_driver(dev);		if (ret == 0)			ret = 1;	} else		ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);	up(&dev->sem);	return ret;} static int __driver_attach(struct device * dev, void * data){	struct device_driver * drv = data; 	/*	 * 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.	 */ 	if (dev->parent)	/* Needed for USB */		down(&dev->parent->sem);	down(&dev->sem);	if (!dev->driver)		driver_probe_device(drv, dev);	up(&dev->sem);	if (dev->parent)		up(&dev->parent->sem); 	return 0;} /** *	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. */int driver_attach(struct device_driver * drv){	return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);} /** *	device_release_driver - manually detach device from driver. *	@dev:	device. * *	Manually detach device from driver. * *	__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) {		get_driver(drv);		driver_sysfs_remove(dev);		sysfs_remove_link(&dev->kobj, "driver");		klist_remove(&dev->knode_driver); 		if (dev->bus)			blocking_notifier_call_chain(&dev->bus->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;		put_driver(drv);	}} 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);}  /** * 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->klist_devices.k_lock);		if (list_empty(&drv->klist_devices.k_list)) {			spin_unlock(&drv->klist_devices.k_lock);			break;		}		dev = list_entry(drv->klist_devices.k_list.prev,				struct device, knode_driver.n_node);		get_device(dev);		spin_unlock(&drv->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);	}} #ifdef CONFIG_PCI_MULTITHREAD_PROBEstatic int __init wait_for_probes(void){	DEFINE_WAIT(wait); 	printk(KERN_INFO "%s: waiting for %d threads\n", __FUNCTION__,			atomic_read(&probe_count));	if (!atomic_read(&probe_count))		return 0;	while (atomic_read(&probe_count)) {		prepare_to_wait(&probe_waitqueue, &wait, TASK_UNINTERRUPTIBLE);		if (atomic_read(&probe_count))			schedule();	}	finish_wait(&probe_waitqueue, &wait);	return 0;} core_initcall_sync(wait_for_probes);postcore_initcall_sync(wait_for_probes);arch_initcall_sync(wait_for_probes);subsys_initcall_sync(wait_for_probes);fs_initcall_sync(wait_for_probes);device_initcall_sync(wait_for_probes);late_initcall_sync(wait_for_probes);#endif EXPORT_SYMBOL_GPL(device_bind_driver);EXPORT_SYMBOL_GPL(device_release_driver);EXPORT_SYMBOL_GPL(device_attach);EXPORT_SYMBOL_GPL(driver_attach);