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![Magnus Damm](/assets/img/avatar_default.png)
Add BUS_NOTIFY_BIND_DRIVER as a bus notifier event. For driver binding/unbinding we with this in place have the following bus notifier events: - BUS_NOTIFY_BIND_DRIVER - before ->probe() - BUS_NOTIFY_BOUND_DRIVER - after ->probe() - BUS_NOTIFY_UNBIND_DRIVER - before ->remove() - BUS_NOTIFY_UNBOUND_DRIVER - after ->remove() The event BUS_NOTIFY_BIND_DRIVER allows bus code to be notified that ->probe() is about to be called. Useful for bus code that needs to setup hardware before the driver gets to run. With this in place platform drivers can be loaded and unloaded as modules and the new BIND event allows bus code to control for instance device clocks that must be enabled before the driver can be executed. Without this patch there is no way for the bus code to get notified that a modular driver is about to be probed. Signed-off-by: Magnus Damm <damm@opensource.se> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
424 lines
10 KiB
C
424 lines
10 KiB
C
/*
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* drivers/base/dd.c - The core device/driver interactions.
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*
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* This file contains the (sometimes tricky) code that controls the
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* interactions between devices and drivers, which primarily includes
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* driver binding and unbinding.
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*
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* All of this code used to exist in drivers/base/bus.c, but was
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* relocated to here in the name of compartmentalization (since it wasn't
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* strictly code just for the 'struct bus_type'.
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*
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* Copyright (c) 2002-5 Patrick Mochel
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* Copyright (c) 2002-3 Open Source Development Labs
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* Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
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* Copyright (c) 2007-2009 Novell Inc.
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*
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* This file is released under the GPLv2
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*/
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#include <linux/device.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/kthread.h>
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#include <linux/wait.h>
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#include <linux/async.h>
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#include <linux/pm_runtime.h>
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#include "base.h"
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#include "power/power.h"
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static void driver_bound(struct device *dev)
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{
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if (klist_node_attached(&dev->p->knode_driver)) {
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printk(KERN_WARNING "%s: device %s already bound\n",
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__func__, kobject_name(&dev->kobj));
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return;
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}
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pr_debug("driver: '%s': %s: bound to device '%s'\n", dev_name(dev),
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__func__, dev->driver->name);
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klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
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if (dev->bus)
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blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
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BUS_NOTIFY_BOUND_DRIVER, dev);
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}
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static int driver_sysfs_add(struct device *dev)
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{
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int ret;
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if (dev->bus)
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blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
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BUS_NOTIFY_BIND_DRIVER, dev);
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ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
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kobject_name(&dev->kobj));
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if (ret == 0) {
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ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
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"driver");
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if (ret)
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sysfs_remove_link(&dev->driver->p->kobj,
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kobject_name(&dev->kobj));
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}
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return ret;
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}
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static void driver_sysfs_remove(struct device *dev)
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{
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struct device_driver *drv = dev->driver;
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if (drv) {
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sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
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sysfs_remove_link(&dev->kobj, "driver");
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}
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}
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/**
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* device_bind_driver - bind a driver to one device.
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* @dev: device.
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*
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* Allow manual attachment of a driver to a device.
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* Caller must have already set @dev->driver.
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*
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* Note that this does not modify the bus reference count
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* nor take the bus's rwsem. Please verify those are accounted
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* for before calling this. (It is ok to call with no other effort
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* from a driver's probe() method.)
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*
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* This function must be called with the device lock held.
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*/
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int device_bind_driver(struct device *dev)
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{
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int ret;
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ret = driver_sysfs_add(dev);
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if (!ret)
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driver_bound(dev);
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return ret;
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}
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EXPORT_SYMBOL_GPL(device_bind_driver);
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static atomic_t probe_count = ATOMIC_INIT(0);
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static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
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static int really_probe(struct device *dev, struct device_driver *drv)
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{
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int ret = 0;
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atomic_inc(&probe_count);
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pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
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drv->bus->name, __func__, drv->name, dev_name(dev));
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WARN_ON(!list_empty(&dev->devres_head));
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dev->driver = drv;
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if (driver_sysfs_add(dev)) {
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printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
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__func__, dev_name(dev));
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goto probe_failed;
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}
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if (dev->bus->probe) {
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ret = dev->bus->probe(dev);
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if (ret)
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goto probe_failed;
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} else if (drv->probe) {
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ret = drv->probe(dev);
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if (ret)
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goto probe_failed;
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}
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driver_bound(dev);
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ret = 1;
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pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
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drv->bus->name, __func__, dev_name(dev), drv->name);
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goto done;
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probe_failed:
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devres_release_all(dev);
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driver_sysfs_remove(dev);
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dev->driver = NULL;
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if (ret != -ENODEV && ret != -ENXIO) {
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/* driver matched but the probe failed */
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printk(KERN_WARNING
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"%s: probe of %s failed with error %d\n",
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drv->name, dev_name(dev), ret);
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}
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/*
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* Ignore errors returned by ->probe so that the next driver can try
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* its luck.
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*/
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ret = 0;
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done:
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atomic_dec(&probe_count);
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wake_up(&probe_waitqueue);
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return ret;
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}
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/**
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* driver_probe_done
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* Determine if the probe sequence is finished or not.
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*
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* Should somehow figure out how to use a semaphore, not an atomic variable...
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*/
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int driver_probe_done(void)
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{
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pr_debug("%s: probe_count = %d\n", __func__,
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atomic_read(&probe_count));
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if (atomic_read(&probe_count))
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return -EBUSY;
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return 0;
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}
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/**
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* wait_for_device_probe
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* Wait for device probing to be completed.
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*/
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void wait_for_device_probe(void)
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{
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/* wait for the known devices to complete their probing */
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wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
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async_synchronize_full();
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}
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EXPORT_SYMBOL_GPL(wait_for_device_probe);
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/**
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* driver_probe_device - attempt to bind device & driver together
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* @drv: driver to bind a device to
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* @dev: device to try to bind to the driver
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*
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* This function returns -ENODEV if the device is not registered,
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* 1 if the device is bound successfully and 0 otherwise.
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*
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* This function must be called with @dev lock held. When called for a
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* USB interface, @dev->parent lock must be held as well.
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*/
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int driver_probe_device(struct device_driver *drv, struct device *dev)
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{
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int ret = 0;
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if (!device_is_registered(dev))
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return -ENODEV;
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pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
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drv->bus->name, __func__, dev_name(dev), drv->name);
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pm_runtime_get_noresume(dev);
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pm_runtime_barrier(dev);
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ret = really_probe(dev, drv);
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pm_runtime_put_sync(dev);
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return ret;
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}
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static int __device_attach(struct device_driver *drv, void *data)
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{
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struct device *dev = data;
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if (!driver_match_device(drv, dev))
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return 0;
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return driver_probe_device(drv, dev);
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}
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/**
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* device_attach - try to attach device to a driver.
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* @dev: device.
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*
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* Walk the list of drivers that the bus has and call
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* driver_probe_device() for each pair. If a compatible
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* pair is found, break out and return.
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*
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* Returns 1 if the device was bound to a driver;
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* 0 if no matching driver was found;
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* -ENODEV if the device is not registered.
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*
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* When called for a USB interface, @dev->parent lock must be held.
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*/
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int device_attach(struct device *dev)
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{
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int ret = 0;
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device_lock(dev);
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if (dev->driver) {
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ret = device_bind_driver(dev);
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if (ret == 0)
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ret = 1;
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else {
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dev->driver = NULL;
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ret = 0;
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}
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} else {
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pm_runtime_get_noresume(dev);
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ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
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pm_runtime_put_sync(dev);
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}
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device_unlock(dev);
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return ret;
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}
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EXPORT_SYMBOL_GPL(device_attach);
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static int __driver_attach(struct device *dev, void *data)
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{
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struct device_driver *drv = data;
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/*
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* Lock device and try to bind to it. We drop the error
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* here and always return 0, because we need to keep trying
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* to bind to devices and some drivers will return an error
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* simply if it didn't support the device.
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*
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* driver_probe_device() will spit a warning if there
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* is an error.
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*/
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if (!driver_match_device(drv, dev))
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return 0;
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if (dev->parent) /* Needed for USB */
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device_lock(dev->parent);
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device_lock(dev);
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if (!dev->driver)
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driver_probe_device(drv, dev);
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device_unlock(dev);
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if (dev->parent)
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device_unlock(dev->parent);
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return 0;
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}
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/**
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* driver_attach - try to bind driver to devices.
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* @drv: driver.
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*
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* Walk the list of devices that the bus has on it and try to
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* match the driver with each one. If driver_probe_device()
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* returns 0 and the @dev->driver is set, we've found a
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* compatible pair.
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*/
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int driver_attach(struct device_driver *drv)
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{
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return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
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}
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EXPORT_SYMBOL_GPL(driver_attach);
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/*
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* __device_release_driver() must be called with @dev lock held.
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* When called for a USB interface, @dev->parent lock must be held as well.
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*/
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static void __device_release_driver(struct device *dev)
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{
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struct device_driver *drv;
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drv = dev->driver;
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if (drv) {
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pm_runtime_get_noresume(dev);
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pm_runtime_barrier(dev);
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driver_sysfs_remove(dev);
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if (dev->bus)
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blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
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BUS_NOTIFY_UNBIND_DRIVER,
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dev);
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if (dev->bus && dev->bus->remove)
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dev->bus->remove(dev);
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else if (drv->remove)
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drv->remove(dev);
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devres_release_all(dev);
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dev->driver = NULL;
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klist_remove(&dev->p->knode_driver);
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if (dev->bus)
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blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
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BUS_NOTIFY_UNBOUND_DRIVER,
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dev);
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pm_runtime_put_sync(dev);
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}
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}
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/**
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* device_release_driver - manually detach device from driver.
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* @dev: device.
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*
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* Manually detach device from driver.
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* When called for a USB interface, @dev->parent lock must be held.
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*/
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void device_release_driver(struct device *dev)
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{
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/*
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* If anyone calls device_release_driver() recursively from
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* within their ->remove callback for the same device, they
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* will deadlock right here.
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*/
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device_lock(dev);
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__device_release_driver(dev);
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device_unlock(dev);
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}
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EXPORT_SYMBOL_GPL(device_release_driver);
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/**
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* driver_detach - detach driver from all devices it controls.
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* @drv: driver.
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*/
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void driver_detach(struct device_driver *drv)
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{
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struct device_private *dev_prv;
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struct device *dev;
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for (;;) {
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spin_lock(&drv->p->klist_devices.k_lock);
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if (list_empty(&drv->p->klist_devices.k_list)) {
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spin_unlock(&drv->p->klist_devices.k_lock);
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break;
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}
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dev_prv = list_entry(drv->p->klist_devices.k_list.prev,
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struct device_private,
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knode_driver.n_node);
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dev = dev_prv->device;
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get_device(dev);
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spin_unlock(&drv->p->klist_devices.k_lock);
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if (dev->parent) /* Needed for USB */
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device_lock(dev->parent);
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device_lock(dev);
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if (dev->driver == drv)
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__device_release_driver(dev);
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device_unlock(dev);
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if (dev->parent)
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device_unlock(dev->parent);
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put_device(dev);
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}
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}
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/*
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* These exports can't be _GPL due to .h files using this within them, and it
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* might break something that was previously working...
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*/
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void *dev_get_drvdata(const struct device *dev)
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{
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if (dev && dev->p)
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return dev->p->driver_data;
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return NULL;
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}
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EXPORT_SYMBOL(dev_get_drvdata);
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void dev_set_drvdata(struct device *dev, void *data)
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{
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int error;
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if (!dev)
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return;
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if (!dev->p) {
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error = device_private_init(dev);
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if (error)
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return;
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}
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dev->p->driver_data = data;
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}
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EXPORT_SYMBOL(dev_set_drvdata);
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