usb.c

omap3 linux 2.6 用nocc去除了冗余代码

/*
 * drivers/usb/core/usb.c
 *
 * (C) Copyright Linus Torvalds 1999
 * (C) Copyright Johannes Erdfelt 1999-2001
 * (C) Copyright Andreas Gal 1999
 * (C) Copyright Gregory P. Smith 1999
 * (C) Copyright Deti Fliegl 1999 (new USB architecture)
 * (C) Copyright Randy Dunlap 2000
 * (C) Copyright David Brownell 2000-2004
 * (C) Copyright Yggdrasil Computing, Inc. 2000
 *     (usb_device_id matching changes by Adam J. Richter)
 * (C) Copyright Greg Kroah-Hartman 2002-2003
 *
 * NOTE! This is not actually a driver at all, rather this is
 * just a collection of helper routines that implement the
 * generic USB things that the real drivers can use..
 *
 * Think of this as a "USB library" rather than anything else.
 * It should be considered a slave, with no callbacks. Callbacks
 * are evil.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/string.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/interrupt.h>  /* for in_interrupt() */
#include <linux/kmod.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/usb.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>

#include <asm/io.h>
#include <asm/scatterlist.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>

#include "hcd.h"
#include "usb.h"


const char *usbcore_name = "usbcore";

static int nousb;	/* Disable USB when built into kernel image */

/* Workqueue for autosuspend and for remote wakeup of root hubs */
struct workqueue_struct *ksuspend_usb_wq;

static int usb_autosuspend_delay = 2;		/* Default delay value,
						 * in seconds */
module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
MODULE_PARM_DESC(autosuspend, "default autosuspend delay");



/**
 * usb_ifnum_to_if - get the interface object with a given interface number
 * @dev: the device whose current configuration is considered
 * @ifnum: the desired interface
 *
 * This walks the device descriptor for the currently active configuration
 * and returns a pointer to the interface with that particular interface
 * number, or null.
 *
 * Note that configuration descriptors are not required to assign interface
 * numbers sequentially, so that it would be incorrect to assume that
 * the first interface in that descriptor corresponds to interface zero.
 * This routine helps device drivers avoid such mistakes.
 * However, you should make sure that you do the right thing with any
 * alternate settings available for this interfaces.
 *
 * Don't call this function unless you are bound to one of the interfaces
 * on this device or you have locked the device!
 */
struct usb_interface *usb_ifnum_to_if(const struct usb_device *dev,
				      unsigned ifnum)
{
	struct usb_host_config *config = dev->actconfig;
	int i;

	if (!config)
		return NULL;
	for (i = 0; i < config->desc.bNumInterfaces; i++)
		if (config->interface[i]->altsetting[0]
				.desc.bInterfaceNumber == ifnum)
			return config->interface[i];

	return NULL;
}

/**
 * usb_altnum_to_altsetting - get the altsetting structure with a given
 *	alternate setting number.
 * @intf: the interface containing the altsetting in question
 * @altnum: the desired alternate setting number
 *
 * This searches the altsetting array of the specified interface for
 * an entry with the correct bAlternateSetting value and returns a pointer
 * to that entry, or null.
 *
 * Note that altsettings need not be stored sequentially by number, so
 * it would be incorrect to assume that the first altsetting entry in
 * the array corresponds to altsetting zero.  This routine helps device
 * drivers avoid such mistakes.
 *
 * Don't call this function unless you are bound to the intf interface
 * or you have locked the device!
 */
struct usb_host_interface *usb_altnum_to_altsetting(const struct usb_interface *intf,
						    unsigned int altnum)
{
	int i;

	for (i = 0; i < intf->num_altsetting; i++) {
		if (intf->altsetting[i].desc.bAlternateSetting == altnum)
			return &intf->altsetting[i];
	}
	return NULL;
}

struct find_interface_arg {
	int minor;
	struct usb_interface *interface;
};

static int __find_interface(struct device * dev, void * data)
{
	struct find_interface_arg *arg = data;
	struct usb_interface *intf;

	/* can't look at usb devices, only interfaces */
	if (is_usb_device(dev))
		return 0;

	intf = to_usb_interface(dev);
	if (intf->minor != -1 && intf->minor == arg->minor) {
		arg->interface = intf;
		return 1;
	}
	return 0;
}

/**
 * usb_find_interface - find usb_interface pointer for driver and device
 * @drv: the driver whose current configuration is considered
 * @minor: the minor number of the desired device
 *
 * This walks the driver device list and returns a pointer to the interface 
 * with the matching minor.  Note, this only works for devices that share the
 * USB major number.
 */
struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
{
	struct find_interface_arg argb;
	int retval;

	argb.minor = minor;
	argb.interface = NULL;
	/* eat the error, it will be in argb.interface */
	retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb,
					__find_interface);
	return argb.interface;
}

/**
 * usb_release_dev - free a usb device structure when all users of it are finished.
 * @dev: device that's been disconnected
 *
 * Will be called only by the device core when all users of this usb device are
 * done.
 */
static void usb_release_dev(struct device *dev)
{
	struct usb_device *udev;

	udev = to_usb_device(dev);

	usb_destroy_configuration(udev);
	usb_put_hcd(bus_to_hcd(udev->bus));
	kfree(udev->product);
	kfree(udev->manufacturer);
	kfree(udev->serial);
	kfree(udev);
}

struct device_type usb_device_type = {
	.name =		"usb_device",
	.release =	usb_release_dev,
};


static int ksuspend_usb_init(void)
{
	/* This workqueue is supposed to be both freezable and
	 * singlethreaded.  Its job doesn't justify running on more
	 * than one CPU.
	 */
	ksuspend_usb_wq = create_freezeable_workqueue("ksuspend_usbd");
	if (!ksuspend_usb_wq)
		return -ENOMEM;
	return 0;
}

static void ksuspend_usb_cleanup(void)
{
	destroy_workqueue(ksuspend_usb_wq);
}


/**
 * usb_alloc_dev - usb device constructor (usbcore-internal)
 * @parent: hub to which device is connected; null to allocate a root hub
 * @bus: bus used to access the device
 * @port1: one-based index of port; ignored for root hubs
 * Context: !in_interrupt()
 *
 * Only hub drivers (including virtual root hub drivers for host
 * controllers) should ever call this.
 *
 * This call may not be used in a non-sleeping context.
 */
struct usb_device *
usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1)
{
	struct usb_device *dev;

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev)
		return NULL;

	if (!usb_get_hcd(bus_to_hcd(bus))) {
		kfree(dev);
		return NULL;
	}

	device_initialize(&dev->dev);
	dev->dev.bus = &usb_bus_type;
	dev->dev.type = &usb_device_type;
	dev->dev.dma_mask = bus->controller->dma_mask;
	dev->state = USB_STATE_ATTACHED;

	INIT_LIST_HEAD(&dev->ep0.urb_list);
	dev->ep0.desc.bLength = USB_DT_ENDPOINT_SIZE;
	dev->ep0.desc.bDescriptorType = USB_DT_ENDPOINT;
	/* ep0 maxpacket comes later, from device descriptor */
	dev->ep_in[0] = dev->ep_out[0] = &dev->ep0;

	/* Save readable and stable topology id, distinguishing devices
	 * by location for diagnostics, tools, driver model, etc.  The
	 * string is a path along hub ports, from the root.  Each device's
	 * dev->devpath will be stable until USB is re-cabled, and hubs
	 * are often labeled with these port numbers.  The bus_id isn't
	 * as stable:  bus->busnum changes easily from modprobe order,
	 * cardbus or pci hotplugging, and so on.
	 */
	if (unlikely(!parent)) {
		dev->devpath[0] = '0';

		dev->dev.parent = bus->controller;
		sprintf(&dev->dev.bus_id[0], "usb%d", bus->busnum);
	} else {
		/* match any labeling on the hubs; it's one-based */
		if (parent->devpath[0] == '0')
			snprintf(dev->devpath, sizeof dev->devpath,
				"%d", port1);
		else
			snprintf(dev->devpath, sizeof dev->devpath,
				"%s.%d", parent->devpath, port1);

		dev->dev.parent = &parent->dev;
		sprintf(&dev->dev.bus_id[0], "%d-%s",
			bus->busnum, dev->devpath);

		/* hub driver sets up TT records */
	}

	dev->portnum = port1;
	dev->bus = bus;
	dev->parent = parent;
	INIT_LIST_HEAD(&dev->filelist);

	mutex_init(&dev->pm_mutex);
	INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work);
	dev->autosuspend_delay = usb_autosuspend_delay * HZ;
	return dev;
}

/**
 * usb_get_dev - increments the reference count of the usb device structure
 * @dev: the device being referenced
 *
 * Each live reference to a device should be refcounted.
 *
 * Drivers for USB interfaces should normally record such references in
 * their probe() methods, when they bind to an interface, and release
 * them by calling usb_put_dev(), in their disconnect() methods.
 *
 * A pointer to the device with the incremented reference counter is returned.
 */
struct usb_device *usb_get_dev(struct usb_device *dev)
{
	if (dev)
		get_device(&dev->dev);
	return dev;
}

/**
 * usb_put_dev - release a use of the usb device structure
 * @dev: device that's been disconnected
 *
 * Must be called when a user of a device is finished with it.  When the last
 * user of the device calls this function, the memory of the device is freed.
 */
void usb_put_dev(struct usb_device *dev)
{
	if (dev)
		put_device(&dev->dev);
}

/**
 * usb_get_intf - increments the reference count of the usb interface structure
 * @intf: the interface being referenced
 *
 * Each live reference to a interface must be refcounted.
 *
 * Drivers for USB interfaces should normally record such references in
 * their probe() methods, when they bind to an interface, and release
 * them by calling usb_put_intf(), in their disconnect() methods.
 *
 * A pointer to the interface with the incremented reference counter is
 * returned.
 */
struct usb_interface *usb_get_intf(struct usb_interface *intf)
{
	if (intf)
		get_device(&intf->dev);
	return intf;
}

/**
 * usb_put_intf - release a use of the usb interface structure
 * @intf: interface that's been decremented
 *
 * Must be called when a user of an interface is finished with it.  When the
 * last user of the interface calls this function, the memory of the interface
 * is freed.
 */
void usb_put_intf(struct usb_interface *intf)
{
	if (intf)
		put_device(&intf->dev);
}


/*			USB device locking
 *
 * USB devices and interfaces are locked using the semaphore in their
 * embedded struct device.  The hub driver guarantees that whenever a
 * device is connected or disconnected, drivers are called with the
 * USB device locked as well as their particular interface.
 *
 * Complications arise when several devices are to be locked at the same
 * time.  Only hub-aware drivers that are part of usbcore ever have to
 * do this; nobody else needs to worry about it.  The rule for locking
 * is simple:
 *
 *	When locking both a device and its parent, always lock the
 *	the parent first.
 */

/**
 * usb_lock_device_for_reset - cautiously acquire the lock for a
 *	usb device structure
 * @udev: device that's being locked
 * @iface: interface bound to the driver making the request (optional)
 *
 * Attempts to acquire the device lock, but fails if the device is
 * NOTATTACHED or SUSPENDED, or if iface is specified and the interface
 * is neither BINDING nor BOUND.  Rather than sleeping to wait for the
 * lock, the routine polls repeatedly.  This is to prevent deadlock with
 * disconnect; in some drivers (such as usb-storage) the disconnect()
 * or suspend() method will block waiting for a device reset to complete.
 *
 * Returns a negative error code for failure, otherwise 1 or 0 to indicate
 * that the device will or will not have to be unlocked.  (0 can be
 * returned when an interface is given and is BINDING, because in that
 * case the driver already owns the device lock.)
 */
int usb_lock_device_for_reset(struct usb_device *udev,
			      const struct usb_interface *iface)
{
	unsigned long jiffies_expire = jiffies + HZ;

	if (udev->state == USB_STATE_NOTATTACHED)
		return -ENODEV;
	if (udev->state == USB_STATE_SUSPENDED)
		return -EHOSTUNREACH;
	if (iface) {
		switch (iface->condition) {
		  case USB_INTERFACE_BINDING:
			return 0;
		  case USB_INTERFACE_BOUND:
			break;
		  default:
			return -EINTR;
		}
	}

	while (usb_trylock_device(udev) != 0) {

		/* If we can't acquire the lock after waiting one second,
		 * we're probably deadlocked */
		if (time_after(jiffies, jiffies_expire))
			return -EBUSY;

		msleep(15);
		if (udev->state == USB_STATE_NOTATTACHED)