usb.c

usb driver for 2.6.17

/*
 * drivers/usb/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/config.h>
#include <linux/module.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/smp_lock.h>
#include <linux/usb.h>
#include <linux/mutex.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 */


/**
 * 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(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(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;
}

/**
 * usb_driver_claim_interface - bind a driver to an interface
 * @driver: the driver to be bound
 * @iface: the interface to which it will be bound; must be in the
 *	usb device's active configuration
 * @priv: driver data associated with that interface
 *
 * This is used by usb device drivers that need to claim more than one
 * interface on a device when probing (audio and acm are current examples).
 * No device driver should directly modify internal usb_interface or
 * usb_device structure members.
 *
 * Few drivers should need to use this routine, since the most natural
 * way to bind to an interface is to return the private data from
 * the driver's probe() method.
 *
 * Callers must own the device lock and the driver model's usb_bus_type.subsys
 * writelock.  So driver probe() entries don't need extra locking,
 * but other call contexts may need to explicitly claim those locks.
 */
int usb_driver_claim_interface(struct usb_driver *driver,
				struct usb_interface *iface, void* priv)
{
	struct device *dev = &iface->dev;

	if (dev->driver)
		return -EBUSY;

	dev->driver = &driver->driver;
	usb_set_intfdata(iface, priv);
	iface->condition = USB_INTERFACE_BOUND;
	mark_active(iface);

	/* if interface was already added, bind now; else let
	 * the future device_add() bind it, bypassing probe()
	 */
	if (device_is_registered(dev))
		device_bind_driver(dev);

	return 0;
}

/**
 * usb_driver_release_interface - unbind a driver from an interface
 * @driver: the driver to be unbound
 * @iface: the interface from which it will be unbound
 *
 * This can be used by drivers to release an interface without waiting
 * for their disconnect() methods to be called.  In typical cases this
 * also causes the driver disconnect() method to be called.
 *
 * This call is synchronous, and may not be used in an interrupt context.
 * Callers must own the device lock and the driver model's usb_bus_type.subsys
 * writelock.  So driver disconnect() entries don't need extra locking,
 * but other call contexts may need to explicitly claim those locks.
 */
void usb_driver_release_interface(struct usb_driver *driver,
					struct usb_interface *iface)
{
	struct device *dev = &iface->dev;

	/* this should never happen, don't release something that's not ours */
	if (!dev->driver || dev->driver != &driver->driver)
		return;

	/* don't release from within disconnect() */
	if (iface->condition != USB_INTERFACE_BOUND)
		return;

	/* don't release if the interface hasn't been added yet */
	if (device_is_registered(dev)) {
		iface->condition = USB_INTERFACE_UNBINDING;
		device_release_driver(dev);
	}

	dev->driver = NULL;
	usb_set_intfdata(iface, NULL);
	iface->condition = USB_INTERFACE_UNBOUND;
	mark_quiesced(iface);
}

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 (dev->driver == &usb_generic_driver)
		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;

	argb.minor = minor;
	argb.interface = NULL;
	driver_for_each_device(&drv->driver, NULL, &argb, __find_interface);
	return argb.interface;
}

#ifdef	CONFIG_HOTPLUG

/*
 * This sends an uevent to userspace, typically helping to load driver
 * or other modules, configure the device, and more.  Drivers can provide
 * a MODULE_DEVICE_TABLE to help with module loading subtasks.
 *
 * We're called either from khubd (the typical case) or from root hub
 * (init, kapmd, modprobe, rmmod, etc), but the agents need to handle
 * delays in event delivery.  Use sysfs (and DEVPATH) to make sure the
 * device (and this configuration!) are still present.
 */
static int usb_uevent(struct device *dev, char **envp, int num_envp,
		      char *buffer, int buffer_size)
{
	struct usb_interface *intf;
	struct usb_device *usb_dev;
	struct usb_host_interface *alt;
	int i = 0;
	int length = 0;

	if (!dev)
		return -ENODEV;

	/* driver is often null here; dev_dbg() would oops */
	pr_debug ("usb %s: uevent\n", dev->bus_id);

	/* Must check driver_data here, as on remove driver is always NULL */
	if ((dev->driver == &usb_generic_driver) || 
	    (dev->driver_data == &usb_generic_driver_data))
		return 0;

	intf = to_usb_interface(dev);
	usb_dev = interface_to_usbdev (intf);
	alt = intf->cur_altsetting;

	if (usb_dev->devnum < 0) {
		pr_debug ("usb %s: already deleted?\n", dev->bus_id);
		return -ENODEV;
	}
	if (!usb_dev->bus) {
		pr_debug ("usb %s: bus removed?\n", dev->bus_id);
		return -ENODEV;
	}

#ifdef	CONFIG_USB_DEVICEFS
	/* If this is available, userspace programs can directly read
	 * all the device descriptors we don't tell them about.  Or
	 * even act as usermode drivers.
	 *
	 * FIXME reduce hardwired intelligence here
	 */
	if (add_uevent_var(envp, num_envp, &i,
			   buffer, buffer_size, &length,
			   "DEVICE=/proc/bus/usb/%03d/%03d",
			   usb_dev->bus->busnum, usb_dev->devnum))
		return -ENOMEM;
#endif

	/* per-device configurations are common */
	if (add_uevent_var(envp, num_envp, &i,
			   buffer, buffer_size, &length,
			   "PRODUCT=%x/%x/%x",
			   le16_to_cpu(usb_dev->descriptor.idVendor),
			   le16_to_cpu(usb_dev->descriptor.idProduct),
			   le16_to_cpu(usb_dev->descriptor.bcdDevice)))
		return -ENOMEM;

	/* class-based driver binding models */
	if (add_uevent_var(envp, num_envp, &i,
			   buffer, buffer_size, &length,
			   "TYPE=%d/%d/%d",
			   usb_dev->descriptor.bDeviceClass,
			   usb_dev->descriptor.bDeviceSubClass,
			   usb_dev->descriptor.bDeviceProtocol))
		return -ENOMEM;

	if (add_uevent_var(envp, num_envp, &i,
			   buffer, buffer_size, &length,
			   "INTERFACE=%d/%d/%d",
			   alt->desc.bInterfaceClass,
			   alt->desc.bInterfaceSubClass,
			   alt->desc.bInterfaceProtocol))
		return -ENOMEM;

	if (add_uevent_var(envp, num_envp, &i,
			   buffer, buffer_size, &length,
			   "MODALIAS=usb:v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02X",
			   le16_to_cpu(usb_dev->descriptor.idVendor),
			   le16_to_cpu(usb_dev->descriptor.idProduct),
			   le16_to_cpu(usb_dev->descriptor.bcdDevice),
			   usb_dev->descriptor.bDeviceClass,
			   usb_dev->descriptor.bDeviceSubClass,
			   usb_dev->descriptor.bDeviceProtocol,
			   alt->desc.bInterfaceClass,
			   alt->desc.bInterfaceSubClass,
			   alt->desc.bInterfaceProtocol))
		return -ENOMEM;

	envp[i] = NULL;

	return 0;
}

#else

static int usb_uevent(struct device *dev, char **envp,
			int num_envp, char *buffer, int buffer_size)
{
	return -ENODEV;
}

#endif	/* CONFIG_HOTPLUG */

/**
 * 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_bus_put(udev->bus);
	kfree(udev->product);
	kfree(udev->manufacturer);
	kfree(udev->serial);
	kfree(udev);
}

/**
 * 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;

	bus = usb_bus_get(bus);
	if (!bus) {
		kfree(dev);
		return NULL;
	}

	device_initialize(&dev->dev);
	dev->dev.bus = &usb_bus_type;
	dev->dev.dma_mask = bus->controller->dma_mask;
	dev->dev.driver_data = &usb_generic_driver_data;
	dev->dev.driver = &usb_generic_driver;
	dev->dev.release = usb_release_dev;
	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 */