201 lines
5.2 KiB
C
201 lines
5.2 KiB
C
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/*
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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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*
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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/module.h>
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#include "base.h"
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#include "power/power.h"
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#define to_drv(node) container_of(node, struct device_driver, kobj.entry)
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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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void device_bind_driver(struct device * dev)
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{
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pr_debug("bound device '%s' to driver '%s'\n",
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dev->bus_id, dev->driver->name);
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list_add_tail(&dev->driver_list, &dev->driver->devices);
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sysfs_create_link(&dev->driver->kobj, &dev->kobj,
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kobject_name(&dev->kobj));
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sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver");
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}
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/**
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* driver_probe_device - attempt to bind device & driver.
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* @drv: driver.
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* @dev: device.
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*
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* First, we call the bus's match function, if one present, which
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* should compare the device IDs the driver supports with the
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* device IDs of the device. Note we don't do this ourselves
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* because we don't know the format of the ID structures, nor what
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* is to be considered a match and what is not.
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*
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* If we find a match, we call @drv->probe(@dev) if it exists, and
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* call device_bind_driver() above.
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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 error = 0;
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if (drv->bus->match && !drv->bus->match(dev, drv))
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return -ENODEV;
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down(&dev->sem);
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dev->driver = drv;
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if (drv->probe) {
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error = drv->probe(dev);
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if (error) {
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dev->driver = NULL;
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up(&dev->sem);
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return error;
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}
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}
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up(&dev->sem);
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device_bind_driver(dev);
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return 0;
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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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int device_attach(struct device * dev)
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{
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struct bus_type * bus = dev->bus;
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struct list_head * entry;
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int error;
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if (dev->driver) {
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device_bind_driver(dev);
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return 1;
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}
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if (bus->match) {
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list_for_each(entry, &bus->drivers.list) {
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struct device_driver * drv = to_drv(entry);
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error = driver_probe_device(drv, dev);
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if (!error)
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/* success, driver matched */
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return 1;
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if (error != -ENODEV && error != -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->bus_id, error);
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}
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}
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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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* Note that we ignore the -ENODEV error from driver_probe_device(),
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* since it's perfectly valid for a driver not to bind to any devices.
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*/
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void driver_attach(struct device_driver * drv)
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{
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struct bus_type * bus = drv->bus;
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struct list_head * entry;
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int error;
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if (!bus->match)
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return;
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list_for_each(entry, &bus->devices.list) {
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struct device * dev = container_of(entry, struct device, bus_list);
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if (!dev->driver) {
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error = driver_probe_device(drv, dev);
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if (error && (error != -ENODEV))
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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->bus_id, error);
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}
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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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* Note that this is called without incrementing the bus
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* reference count nor taking the bus's rwsem. Be sure that
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* those are accounted for before calling this function.
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*/
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void device_release_driver(struct device * dev)
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{
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struct device_driver * drv;
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down(&dev->sem);
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drv = dev->driver;
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if (drv) {
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sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
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sysfs_remove_link(&dev->kobj, "driver");
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list_del_init(&dev->driver_list);
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if (drv->remove)
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drv->remove(dev);
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dev->driver = NULL;
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}
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up(&dev->sem);
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}
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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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while (!list_empty(&drv->devices)) {
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struct device * dev = container_of(drv->devices.next, struct device, driver_list);
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device_release_driver(dev);
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}
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}
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EXPORT_SYMBOL_GPL(driver_probe_device);
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EXPORT_SYMBOL_GPL(device_bind_driver);
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EXPORT_SYMBOL_GPL(device_release_driver);
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EXPORT_SYMBOL_GPL(device_attach);
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EXPORT_SYMBOL_GPL(driver_attach);
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