1/*
   2 * message.c - synchronous message handling
   3 */
   4
   5#include <linux/pci.h>	/* for scatterlist macros */
   6#include <linux/usb.h>
   7#include <linux/module.h>
   8#include <linux/slab.h>
 
   9#include <linux/mm.h>
  10#include <linux/timer.h>
  11#include <linux/ctype.h>
  12#include <linux/nls.h>
  13#include <linux/device.h>
  14#include <linux/scatterlist.h>
  15#include <linux/usb/quirks.h>
  16#include <linux/usb/hcd.h>	/* for usbcore internals */
  17#include <asm/byteorder.h>
  18
  19#include "usb.h"
  20
  21static void cancel_async_set_config(struct usb_device *udev);
  22
  23struct api_context {
  24	struct completion	done;
  25	int			status;
  26};
  27
  28static void usb_api_blocking_completion(struct urb *urb)
  29{
  30	struct api_context *ctx = urb->context;
  31
  32	ctx->status = urb->status;
  33	complete(&ctx->done);
  34}
  35
  36
  37/*
  38 * Starts urb and waits for completion or timeout. Note that this call
  39 * is NOT interruptible. Many device driver i/o requests should be
  40 * interruptible and therefore these drivers should implement their
  41 * own interruptible routines.
  42 */
  43static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)
  44{
  45	struct api_context ctx;
  46	unsigned long expire;
  47	int retval;
  48
  49	init_completion(&ctx.done);
  50	urb->context = &ctx;
  51	urb->actual_length = 0;
  52	retval = usb_submit_urb(urb, GFP_NOIO);
  53	if (unlikely(retval))
  54		goto out;
  55
  56	expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT;
  57	if (!wait_for_completion_timeout(&ctx.done, expire)) {
  58		usb_kill_urb(urb);
  59		retval = (ctx.status == -ENOENT ? -ETIMEDOUT : ctx.status);
  60
  61		dev_dbg(&urb->dev->dev,
  62			"%s timed out on ep%d%s len=%u/%u\n",
  63			current->comm,
  64			usb_endpoint_num(&urb->ep->desc),
  65			usb_urb_dir_in(urb) ? "in" : "out",
  66			urb->actual_length,
  67			urb->transfer_buffer_length);
  68	} else
  69		retval = ctx.status;
  70out:
  71	if (actual_length)
  72		*actual_length = urb->actual_length;
  73
  74	usb_free_urb(urb);
  75	return retval;
  76}
  77
  78/*-------------------------------------------------------------------*/
  79/* returns status (negative) or length (positive) */
  80static int usb_internal_control_msg(struct usb_device *usb_dev,
  81				    unsigned int pipe,
  82				    struct usb_ctrlrequest *cmd,
  83				    void *data, int len, int timeout)
  84{
  85	struct urb *urb;
  86	int retv;
  87	int length;
  88
  89	urb = usb_alloc_urb(0, GFP_NOIO);
  90	if (!urb)
  91		return -ENOMEM;
  92
  93	usb_fill_control_urb(urb, usb_dev, pipe, (unsigned char *)cmd, data,
  94			     len, usb_api_blocking_completion, NULL);
  95
  96	retv = usb_start_wait_urb(urb, timeout, &length);
  97	if (retv < 0)
  98		return retv;
  99	else
 100		return length;
 101}
 102
 103/**
 104 * usb_control_msg - Builds a control urb, sends it off and waits for completion
 105 * @dev: pointer to the usb device to send the message to
 106 * @pipe: endpoint "pipe" to send the message to
 107 * @request: USB message request value
 108 * @requesttype: USB message request type value
 109 * @value: USB message value
 110 * @index: USB message index value
 111 * @data: pointer to the data to send
 112 * @size: length in bytes of the data to send
 113 * @timeout: time in msecs to wait for the message to complete before timing
 114 *	out (if 0 the wait is forever)
 115 *
 116 * Context: !in_interrupt ()
 117 *
 118 * This function sends a simple control message to a specified endpoint and
 119 * waits for the message to complete, or timeout.
 120 *
 
 
 
 121 * Don't use this function from within an interrupt context, like a bottom half
 122 * handler.  If you need an asynchronous message, or need to send a message
 123 * from within interrupt context, use usb_submit_urb().
 124 * If a thread in your driver uses this call, make sure your disconnect()
 125 * method can wait for it to complete.  Since you don't have a handle on the
 126 * URB used, you can't cancel the request.
 127 *
 128 * Return: If successful, the number of bytes transferred. Otherwise, a negative
 129 * error number.
 130 */
 131int usb_control_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
 132		    __u8 requesttype, __u16 value, __u16 index, void *data,
 133		    __u16 size, int timeout)
 134{
 135	struct usb_ctrlrequest *dr;
 136	int ret;
 137
 138	dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_NOIO);
 139	if (!dr)
 140		return -ENOMEM;
 141
 142	dr->bRequestType = requesttype;
 143	dr->bRequest = request;
 144	dr->wValue = cpu_to_le16(value);
 145	dr->wIndex = cpu_to_le16(index);
 146	dr->wLength = cpu_to_le16(size);
 147
 
 
 148	ret = usb_internal_control_msg(dev, pipe, dr, data, size, timeout);
 149
 150	kfree(dr);
 151
 152	return ret;
 153}
 154EXPORT_SYMBOL_GPL(usb_control_msg);
 155
 156/**
 157 * usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for completion
 158 * @usb_dev: pointer to the usb device to send the message to
 159 * @pipe: endpoint "pipe" to send the message to
 160 * @data: pointer to the data to send
 161 * @len: length in bytes of the data to send
 162 * @actual_length: pointer to a location to put the actual length transferred
 163 *	in bytes
 164 * @timeout: time in msecs to wait for the message to complete before
 165 *	timing out (if 0 the wait is forever)
 166 *
 167 * Context: !in_interrupt ()
 168 *
 169 * This function sends a simple interrupt message to a specified endpoint and
 170 * waits for the message to complete, or timeout.
 171 *
 
 
 
 172 * Don't use this function from within an interrupt context, like a bottom half
 173 * handler.  If you need an asynchronous message, or need to send a message
 174 * from within interrupt context, use usb_submit_urb() If a thread in your
 175 * driver uses this call, make sure your disconnect() method can wait for it to
 176 * complete.  Since you don't have a handle on the URB used, you can't cancel
 177 * the request.
 178 *
 179 * Return:
 180 * If successful, 0. Otherwise a negative error number. The number of actual
 181 * bytes transferred will be stored in the @actual_length parameter.
 182 */
 183int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe,
 184		      void *data, int len, int *actual_length, int timeout)
 185{
 186	return usb_bulk_msg(usb_dev, pipe, data, len, actual_length, timeout);
 187}
 188EXPORT_SYMBOL_GPL(usb_interrupt_msg);
 189
 190/**
 191 * usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion
 192 * @usb_dev: pointer to the usb device to send the message to
 193 * @pipe: endpoint "pipe" to send the message to
 194 * @data: pointer to the data to send
 195 * @len: length in bytes of the data to send
 196 * @actual_length: pointer to a location to put the actual length transferred
 197 *	in bytes
 198 * @timeout: time in msecs to wait for the message to complete before
 199 *	timing out (if 0 the wait is forever)
 200 *
 201 * Context: !in_interrupt ()
 202 *
 203 * This function sends a simple bulk message to a specified endpoint
 204 * and waits for the message to complete, or timeout.
 205 *
 
 
 
 206 * Don't use this function from within an interrupt context, like a bottom half
 207 * handler.  If you need an asynchronous message, or need to send a message
 208 * from within interrupt context, use usb_submit_urb() If a thread in your
 209 * driver uses this call, make sure your disconnect() method can wait for it to
 210 * complete.  Since you don't have a handle on the URB used, you can't cancel
 211 * the request.
 212 *
 213 * Because there is no usb_interrupt_msg() and no USBDEVFS_INTERRUPT ioctl,
 214 * users are forced to abuse this routine by using it to submit URBs for
 215 * interrupt endpoints.  We will take the liberty of creating an interrupt URB
 216 * (with the default interval) if the target is an interrupt endpoint.
 217 *
 218 * Return:
 219 * If successful, 0. Otherwise a negative error number. The number of actual
 220 * bytes transferred will be stored in the @actual_length parameter.
 221 *
 222 */
 223int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe,
 224		 void *data, int len, int *actual_length, int timeout)
 225{
 226	struct urb *urb;
 227	struct usb_host_endpoint *ep;
 228
 229	ep = usb_pipe_endpoint(usb_dev, pipe);
 230	if (!ep || len < 0)
 231		return -EINVAL;
 232
 233	urb = usb_alloc_urb(0, GFP_KERNEL);
 234	if (!urb)
 235		return -ENOMEM;
 236
 237	if ((ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
 238			USB_ENDPOINT_XFER_INT) {
 239		pipe = (pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30);
 240		usb_fill_int_urb(urb, usb_dev, pipe, data, len,
 241				usb_api_blocking_completion, NULL,
 242				ep->desc.bInterval);
 243	} else
 244		usb_fill_bulk_urb(urb, usb_dev, pipe, data, len,
 245				usb_api_blocking_completion, NULL);
 246
 247	return usb_start_wait_urb(urb, timeout, actual_length);
 248}
 249EXPORT_SYMBOL_GPL(usb_bulk_msg);
 250
 251/*-------------------------------------------------------------------*/
 252
 253static void sg_clean(struct usb_sg_request *io)
 254{
 255	if (io->urbs) {
 256		while (io->entries--)
 257			usb_free_urb(io->urbs[io->entries]);
 258		kfree(io->urbs);
 259		io->urbs = NULL;
 260	}
 261	io->dev = NULL;
 262}
 263
 264static void sg_complete(struct urb *urb)
 265{
 266	struct usb_sg_request *io = urb->context;
 267	int status = urb->status;
 268
 269	spin_lock(&io->lock);
 270
 271	/* In 2.5 we require hcds' endpoint queues not to progress after fault
 272	 * reports, until the completion callback (this!) returns.  That lets
 273	 * device driver code (like this routine) unlink queued urbs first,
 274	 * if it needs to, since the HC won't work on them at all.  So it's
 275	 * not possible for page N+1 to overwrite page N, and so on.
 276	 *
 277	 * That's only for "hard" faults; "soft" faults (unlinks) sometimes
 278	 * complete before the HCD can get requests away from hardware,
 279	 * though never during cleanup after a hard fault.
 280	 */
 281	if (io->status
 282			&& (io->status != -ECONNRESET
 283				|| status != -ECONNRESET)
 284			&& urb->actual_length) {
 285		dev_err(io->dev->bus->controller,
 286			"dev %s ep%d%s scatterlist error %d/%d\n",
 287			io->dev->devpath,
 288			usb_endpoint_num(&urb->ep->desc),
 289			usb_urb_dir_in(urb) ? "in" : "out",
 290			status, io->status);
 291		/* BUG (); */
 292	}
 293
 294	if (io->status == 0 && status && status != -ECONNRESET) {
 295		int i, found, retval;
 296
 297		io->status = status;
 298
 299		/* the previous urbs, and this one, completed already.
 300		 * unlink pending urbs so they won't rx/tx bad data.
 301		 * careful: unlink can sometimes be synchronous...
 302		 */
 303		spin_unlock(&io->lock);
 304		for (i = 0, found = 0; i < io->entries; i++) {
 305			if (!io->urbs[i] || !io->urbs[i]->dev)
 306				continue;
 307			if (found) {
 308				retval = usb_unlink_urb(io->urbs[i]);
 309				if (retval != -EINPROGRESS &&
 310				    retval != -ENODEV &&
 311				    retval != -EBUSY &&
 312				    retval != -EIDRM)
 313					dev_err(&io->dev->dev,
 314						"%s, unlink --> %d\n",
 315						__func__, retval);
 316			} else if (urb == io->urbs[i])
 317				found = 1;
 318		}
 319		spin_lock(&io->lock);
 320	}
 321
 322	/* on the last completion, signal usb_sg_wait() */
 323	io->bytes += urb->actual_length;
 324	io->count--;
 325	if (!io->count)
 326		complete(&io->complete);
 327
 328	spin_unlock(&io->lock);
 329}
 330
 331
 332/**
 333 * usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request
 334 * @io: request block being initialized.  until usb_sg_wait() returns,
 335 *	treat this as a pointer to an opaque block of memory,
 336 * @dev: the usb device that will send or receive the data
 337 * @pipe: endpoint "pipe" used to transfer the data
 338 * @period: polling rate for interrupt endpoints, in frames or
 339 * 	(for high speed endpoints) microframes; ignored for bulk
 340 * @sg: scatterlist entries
 341 * @nents: how many entries in the scatterlist
 342 * @length: how many bytes to send from the scatterlist, or zero to
 343 * 	send every byte identified in the list.
 344 * @mem_flags: SLAB_* flags affecting memory allocations in this call
 345 *
 346 * This initializes a scatter/gather request, allocating resources such as
 347 * I/O mappings and urb memory (except maybe memory used by USB controller
 348 * drivers).
 349 *
 350 * The request must be issued using usb_sg_wait(), which waits for the I/O to
 351 * complete (or to be canceled) and then cleans up all resources allocated by
 352 * usb_sg_init().
 353 *
 354 * The request may be canceled with usb_sg_cancel(), either before or after
 355 * usb_sg_wait() is called.
 356 *
 357 * Return: Zero for success, else a negative errno value.
 358 */
 359int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
 360		unsigned pipe, unsigned	period, struct scatterlist *sg,
 361		int nents, size_t length, gfp_t mem_flags)
 362{
 363	int i;
 364	int urb_flags;
 365	int use_sg;
 366
 367	if (!io || !dev || !sg
 368			|| usb_pipecontrol(pipe)
 369			|| usb_pipeisoc(pipe)
 370			|| nents <= 0)
 371		return -EINVAL;
 372
 373	spin_lock_init(&io->lock);
 374	io->dev = dev;
 375	io->pipe = pipe;
 376
 377	if (dev->bus->sg_tablesize > 0) {
 378		use_sg = true;
 379		io->entries = 1;
 380	} else {
 381		use_sg = false;
 382		io->entries = nents;
 383	}
 384
 385	/* initialize all the urbs we'll use */
 386	io->urbs = kmalloc(io->entries * sizeof(*io->urbs), mem_flags);
 387	if (!io->urbs)
 388		goto nomem;
 389
 390	urb_flags = URB_NO_INTERRUPT;
 391	if (usb_pipein(pipe))
 392		urb_flags |= URB_SHORT_NOT_OK;
 393
 394	for_each_sg(sg, sg, io->entries, i) {
 395		struct urb *urb;
 396		unsigned len;
 397
 398		urb = usb_alloc_urb(0, mem_flags);
 399		if (!urb) {
 400			io->entries = i;
 401			goto nomem;
 402		}
 403		io->urbs[i] = urb;
 404
 405		urb->dev = NULL;
 406		urb->pipe = pipe;
 407		urb->interval = period;
 408		urb->transfer_flags = urb_flags;
 409		urb->complete = sg_complete;
 410		urb->context = io;
 411		urb->sg = sg;
 412
 413		if (use_sg) {
 414			/* There is no single transfer buffer */
 415			urb->transfer_buffer = NULL;
 416			urb->num_sgs = nents;
 417
 418			/* A length of zero means transfer the whole sg list */
 419			len = length;
 420			if (len == 0) {
 421				struct scatterlist	*sg2;
 422				int			j;
 423
 424				for_each_sg(sg, sg2, nents, j)
 425					len += sg2->length;
 426			}
 427		} else {
 428			/*
 429			 * Some systems can't use DMA; they use PIO instead.
 430			 * For their sakes, transfer_buffer is set whenever
 431			 * possible.
 432			 */
 433			if (!PageHighMem(sg_page(sg)))
 434				urb->transfer_buffer = sg_virt(sg);
 435			else
 436				urb->transfer_buffer = NULL;
 437
 438			len = sg->length;
 439			if (length) {
 440				len = min_t(size_t, len, length);
 441				length -= len;
 442				if (length == 0)
 443					io->entries = i + 1;
 444			}
 445		}
 446		urb->transfer_buffer_length = len;
 447	}
 448	io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT;
 449
 450	/* transaction state */
 451	io->count = io->entries;
 452	io->status = 0;
 453	io->bytes = 0;
 454	init_completion(&io->complete);
 455	return 0;
 456
 457nomem:
 458	sg_clean(io);
 459	return -ENOMEM;
 460}
 461EXPORT_SYMBOL_GPL(usb_sg_init);
 462
 463/**
 464 * usb_sg_wait - synchronously execute scatter/gather request
 465 * @io: request block handle, as initialized with usb_sg_init().
 466 * 	some fields become accessible when this call returns.
 467 * Context: !in_interrupt ()
 468 *
 469 * This function blocks until the specified I/O operation completes.  It
 470 * leverages the grouping of the related I/O requests to get good transfer
 471 * rates, by queueing the requests.  At higher speeds, such queuing can
 472 * significantly improve USB throughput.
 473 *
 474 * There are three kinds of completion for this function.
 475 * (1) success, where io->status is zero.  The number of io->bytes
 476 *     transferred is as requested.
 477 * (2) error, where io->status is a negative errno value.  The number
 478 *     of io->bytes transferred before the error is usually less
 479 *     than requested, and can be nonzero.
 480 * (3) cancellation, a type of error with status -ECONNRESET that
 481 *     is initiated by usb_sg_cancel().
 482 *
 483 * When this function returns, all memory allocated through usb_sg_init() or
 484 * this call will have been freed.  The request block parameter may still be
 485 * passed to usb_sg_cancel(), or it may be freed.  It could also be
 486 * reinitialized and then reused.
 487 *
 488 * Data Transfer Rates:
 489 *
 490 * Bulk transfers are valid for full or high speed endpoints.
 491 * The best full speed data rate is 19 packets of 64 bytes each
 492 * per frame, or 1216 bytes per millisecond.
 493 * The best high speed data rate is 13 packets of 512 bytes each
 494 * per microframe, or 52 KBytes per millisecond.
 495 *
 496 * The reason to use interrupt transfers through this API would most likely
 497 * be to reserve high speed bandwidth, where up to 24 KBytes per millisecond
 498 * could be transferred.  That capability is less useful for low or full
 499 * speed interrupt endpoints, which allow at most one packet per millisecond,
 500 * of at most 8 or 64 bytes (respectively).
 501 *
 502 * It is not necessary to call this function to reserve bandwidth for devices
 503 * under an xHCI host controller, as the bandwidth is reserved when the
 504 * configuration or interface alt setting is selected.
 505 */
 506void usb_sg_wait(struct usb_sg_request *io)
 507{
 508	int i;
 509	int entries = io->entries;
 510
 511	/* queue the urbs.  */
 512	spin_lock_irq(&io->lock);
 513	i = 0;
 514	while (i < entries && !io->status) {
 515		int retval;
 516
 517		io->urbs[i]->dev = io->dev;
 518		retval = usb_submit_urb(io->urbs[i], GFP_ATOMIC);
 519
 520		/* after we submit, let completions or cancellations fire;
 521		 * we handshake using io->status.
 522		 */
 523		spin_unlock_irq(&io->lock);
 524		switch (retval) {
 525			/* maybe we retrying will recover */
 526		case -ENXIO:	/* hc didn't queue this one */
 527		case -EAGAIN:
 528		case -ENOMEM:
 529			retval = 0;
 530			yield();
 531			break;
 532
 533			/* no error? continue immediately.
 534			 *
 535			 * NOTE: to work better with UHCI (4K I/O buffer may
 536			 * need 3K of TDs) it may be good to limit how many
 537			 * URBs are queued at once; N milliseconds?
 538			 */
 539		case 0:
 540			++i;
 541			cpu_relax();
 542			break;
 543
 544			/* fail any uncompleted urbs */
 545		default:
 546			io->urbs[i]->status = retval;
 547			dev_dbg(&io->dev->dev, "%s, submit --> %d\n",
 548				__func__, retval);
 549			usb_sg_cancel(io);
 550		}
 551		spin_lock_irq(&io->lock);
 552		if (retval && (io->status == 0 || io->status == -ECONNRESET))
 553			io->status = retval;
 554	}
 555	io->count -= entries - i;
 556	if (io->count == 0)
 557		complete(&io->complete);
 558	spin_unlock_irq(&io->lock);
 559
 560	/* OK, yes, this could be packaged as non-blocking.
 561	 * So could the submit loop above ... but it's easier to
 562	 * solve neither problem than to solve both!
 563	 */
 564	wait_for_completion(&io->complete);
 565
 566	sg_clean(io);
 567}
 568EXPORT_SYMBOL_GPL(usb_sg_wait);
 569
 570/**
 571 * usb_sg_cancel - stop scatter/gather i/o issued by usb_sg_wait()
 572 * @io: request block, initialized with usb_sg_init()
 573 *
 574 * This stops a request after it has been started by usb_sg_wait().
 575 * It can also prevents one initialized by usb_sg_init() from starting,
 576 * so that call just frees resources allocated to the request.
 577 */
 578void usb_sg_cancel(struct usb_sg_request *io)
 579{
 580	unsigned long flags;
 581
 582	spin_lock_irqsave(&io->lock, flags);
 583
 584	/* shut everything down, if it didn't already */
 585	if (!io->status) {
 586		int i;
 587
 588		io->status = -ECONNRESET;
 589		spin_unlock(&io->lock);
 590		for (i = 0; i < io->entries; i++) {
 591			int retval;
 592
 593			if (!io->urbs[i]->dev)
 594				continue;
 595			retval = usb_unlink_urb(io->urbs[i]);
 596			if (retval != -EINPROGRESS
 597					&& retval != -ENODEV
 598					&& retval != -EBUSY
 599					&& retval != -EIDRM)
 600				dev_warn(&io->dev->dev, "%s, unlink --> %d\n",
 601					__func__, retval);
 602		}
 603		spin_lock(&io->lock);
 604	}
 605	spin_unlock_irqrestore(&io->lock, flags);
 606}
 607EXPORT_SYMBOL_GPL(usb_sg_cancel);
 608
 609/*-------------------------------------------------------------------*/
 610
 611/**
 612 * usb_get_descriptor - issues a generic GET_DESCRIPTOR request
 613 * @dev: the device whose descriptor is being retrieved
 614 * @type: the descriptor type (USB_DT_*)
 615 * @index: the number of the descriptor
 616 * @buf: where to put the descriptor
 617 * @size: how big is "buf"?
 618 * Context: !in_interrupt ()
 619 *
 620 * Gets a USB descriptor.  Convenience functions exist to simplify
 621 * getting some types of descriptors.  Use
 622 * usb_get_string() or usb_string() for USB_DT_STRING.
 623 * Device (USB_DT_DEVICE) and configuration descriptors (USB_DT_CONFIG)
 624 * are part of the device structure.
 625 * In addition to a number of USB-standard descriptors, some
 626 * devices also use class-specific or vendor-specific descriptors.
 627 *
 628 * This call is synchronous, and may not be used in an interrupt context.
 629 *
 630 * Return: The number of bytes received on success, or else the status code
 631 * returned by the underlying usb_control_msg() call.
 632 */
 633int usb_get_descriptor(struct usb_device *dev, unsigned char type,
 634		       unsigned char index, void *buf, int size)
 635{
 636	int i;
 637	int result;
 638
 639	memset(buf, 0, size);	/* Make sure we parse really received data */
 640
 641	for (i = 0; i < 3; ++i) {
 642		/* retry on length 0 or error; some devices are flakey */
 643		result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
 644				USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
 645				(type << 8) + index, 0, buf, size,
 646				USB_CTRL_GET_TIMEOUT);
 647		if (result <= 0 && result != -ETIMEDOUT)
 648			continue;
 649		if (result > 1 && ((u8 *)buf)[1] != type) {
 650			result = -ENODATA;
 651			continue;
 652		}
 653		break;
 654	}
 655	return result;
 656}
 657EXPORT_SYMBOL_GPL(usb_get_descriptor);
 658
 659/**
 660 * usb_get_string - gets a string descriptor
 661 * @dev: the device whose string descriptor is being retrieved
 662 * @langid: code for language chosen (from string descriptor zero)
 663 * @index: the number of the descriptor
 664 * @buf: where to put the string
 665 * @size: how big is "buf"?
 666 * Context: !in_interrupt ()
 667 *
 668 * Retrieves a string, encoded using UTF-16LE (Unicode, 16 bits per character,
 669 * in little-endian byte order).
 670 * The usb_string() function will often be a convenient way to turn
 671 * these strings into kernel-printable form.
 672 *
 673 * Strings may be referenced in device, configuration, interface, or other
 674 * descriptors, and could also be used in vendor-specific ways.
 675 *
 676 * This call is synchronous, and may not be used in an interrupt context.
 677 *
 678 * Return: The number of bytes received on success, or else the status code
 679 * returned by the underlying usb_control_msg() call.
 680 */
 681static int usb_get_string(struct usb_device *dev, unsigned short langid,
 682			  unsigned char index, void *buf, int size)
 683{
 684	int i;
 685	int result;
 686
 687	for (i = 0; i < 3; ++i) {
 688		/* retry on length 0 or stall; some devices are flakey */
 689		result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
 690			USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
 691			(USB_DT_STRING << 8) + index, langid, buf, size,
 692			USB_CTRL_GET_TIMEOUT);
 693		if (result == 0 || result == -EPIPE)
 694			continue;
 695		if (result > 1 && ((u8 *) buf)[1] != USB_DT_STRING) {
 696			result = -ENODATA;
 697			continue;
 698		}
 699		break;
 700	}
 701	return result;
 702}
 703
 704static void usb_try_string_workarounds(unsigned char *buf, int *length)
 705{
 706	int newlength, oldlength = *length;
 707
 708	for (newlength = 2; newlength + 1 < oldlength; newlength += 2)
 709		if (!isprint(buf[newlength]) || buf[newlength + 1])
 710			break;
 711
 712	if (newlength > 2) {
 713		buf[0] = newlength;
 714		*length = newlength;
 715	}
 716}
 717
 718static int usb_string_sub(struct usb_device *dev, unsigned int langid,
 719			  unsigned int index, unsigned char *buf)
 720{
 721	int rc;
 722
 723	/* Try to read the string descriptor by asking for the maximum
 724	 * possible number of bytes */
 725	if (dev->quirks & USB_QUIRK_STRING_FETCH_255)
 726		rc = -EIO;
 727	else
 728		rc = usb_get_string(dev, langid, index, buf, 255);
 729
 730	/* If that failed try to read the descriptor length, then
 731	 * ask for just that many bytes */
 732	if (rc < 2) {
 733		rc = usb_get_string(dev, langid, index, buf, 2);
 734		if (rc == 2)
 735			rc = usb_get_string(dev, langid, index, buf, buf[0]);
 736	}
 737
 738	if (rc >= 2) {
 739		if (!buf[0] && !buf[1])
 740			usb_try_string_workarounds(buf, &rc);
 741
 742		/* There might be extra junk at the end of the descriptor */
 743		if (buf[0] < rc)
 744			rc = buf[0];
 745
 746		rc = rc - (rc & 1); /* force a multiple of two */
 747	}
 748
 749	if (rc < 2)
 750		rc = (rc < 0 ? rc : -EINVAL);
 751
 752	return rc;
 753}
 754
 755static int usb_get_langid(struct usb_device *dev, unsigned char *tbuf)
 756{
 757	int err;
 758
 759	if (dev->have_langid)
 760		return 0;
 761
 762	if (dev->string_langid < 0)
 763		return -EPIPE;
 764
 765	err = usb_string_sub(dev, 0, 0, tbuf);
 766
 767	/* If the string was reported but is malformed, default to english
 768	 * (0x0409) */
 769	if (err == -ENODATA || (err > 0 && err < 4)) {
 770		dev->string_langid = 0x0409;
 771		dev->have_langid = 1;
 772		dev_err(&dev->dev,
 773			"language id specifier not provided by device, defaulting to English\n");
 
 
 774		return 0;
 775	}
 776
 777	/* In case of all other errors, we assume the device is not able to
 778	 * deal with strings at all. Set string_langid to -1 in order to
 779	 * prevent any string to be retrieved from the device */
 780	if (err < 0) {
 781		dev_err(&dev->dev, "string descriptor 0 read error: %d\n",
 782					err);
 783		dev->string_langid = -1;
 784		return -EPIPE;
 785	}
 786
 787	/* always use the first langid listed */
 788	dev->string_langid = tbuf[2] | (tbuf[3] << 8);
 789	dev->have_langid = 1;
 790	dev_dbg(&dev->dev, "default language 0x%04x\n",
 791				dev->string_langid);
 792	return 0;
 793}
 794
 795/**
 796 * usb_string - returns UTF-8 version of a string descriptor
 797 * @dev: the device whose string descriptor is being retrieved
 798 * @index: the number of the descriptor
 799 * @buf: where to put the string
 800 * @size: how big is "buf"?
 801 * Context: !in_interrupt ()
 802 *
 803 * This converts the UTF-16LE encoded strings returned by devices, from
 804 * usb_get_string_descriptor(), to null-terminated UTF-8 encoded ones
 805 * that are more usable in most kernel contexts.  Note that this function
 806 * chooses strings in the first language supported by the device.
 807 *
 808 * This call is synchronous, and may not be used in an interrupt context.
 809 *
 810 * Return: length of the string (>= 0) or usb_control_msg status (< 0).
 811 */
 812int usb_string(struct usb_device *dev, int index, char *buf, size_t size)
 813{
 814	unsigned char *tbuf;
 815	int err;
 816
 817	if (dev->state == USB_STATE_SUSPENDED)
 818		return -EHOSTUNREACH;
 819	if (size <= 0 || !buf || !index)
 820		return -EINVAL;
 821	buf[0] = 0;
 822	tbuf = kmalloc(256, GFP_NOIO);
 823	if (!tbuf)
 824		return -ENOMEM;
 825
 826	err = usb_get_langid(dev, tbuf);
 827	if (err < 0)
 828		goto errout;
 829
 830	err = usb_string_sub(dev, dev->string_langid, index, tbuf);
 831	if (err < 0)
 832		goto errout;
 833
 834	size--;		/* leave room for trailing NULL char in output buffer */
 835	err = utf16s_to_utf8s((wchar_t *) &tbuf[2], (err - 2) / 2,
 836			UTF16_LITTLE_ENDIAN, buf, size);
 837	buf[err] = 0;
 838
 839	if (tbuf[1] != USB_DT_STRING)
 840		dev_dbg(&dev->dev,
 841			"wrong descriptor type %02x for string %d (\"%s\")\n",
 842			tbuf[1], index, buf);
 843
 844 errout:
 845	kfree(tbuf);
 846	return err;
 847}
 848EXPORT_SYMBOL_GPL(usb_string);
 849
 850/* one UTF-8-encoded 16-bit character has at most three bytes */
 851#define MAX_USB_STRING_SIZE (127 * 3 + 1)
 852
 853/**
 854 * usb_cache_string - read a string descriptor and cache it for later use
 855 * @udev: the device whose string descriptor is being read
 856 * @index: the descriptor index
 857 *
 858 * Return: A pointer to a kmalloc'ed buffer containing the descriptor string,
 859 * or %NULL if the index is 0 or the string could not be read.
 860 */
 861char *usb_cache_string(struct usb_device *udev, int index)
 862{
 863	char *buf;
 864	char *smallbuf = NULL;
 865	int len;
 866
 867	if (index <= 0)
 868		return NULL;
 869
 870	buf = kmalloc(MAX_USB_STRING_SIZE, GFP_NOIO);
 871	if (buf) {
 872		len = usb_string(udev, index, buf, MAX_USB_STRING_SIZE);
 873		if (len > 0) {
 874			smallbuf = kmalloc(++len, GFP_NOIO);
 875			if (!smallbuf)
 876				return buf;
 877			memcpy(smallbuf, buf, len);
 878		}
 879		kfree(buf);
 880	}
 881	return smallbuf;
 882}
 883
 884/*
 885 * usb_get_device_descriptor - (re)reads the device descriptor (usbcore)
 886 * @dev: the device whose device descriptor is being updated
 887 * @size: how much of the descriptor to read
 888 * Context: !in_interrupt ()
 889 *
 890 * Updates the copy of the device descriptor stored in the device structure,
 891 * which dedicates space for this purpose.
 892 *
 893 * Not exported, only for use by the core.  If drivers really want to read
 894 * the device descriptor directly, they can call usb_get_descriptor() with
 895 * type = USB_DT_DEVICE and index = 0.
 896 *
 897 * This call is synchronous, and may not be used in an interrupt context.
 898 *
 899 * Return: The number of bytes received on success, or else the status code
 900 * returned by the underlying usb_control_msg() call.
 901 */
 902int usb_get_device_descriptor(struct usb_device *dev, unsigned int size)
 903{
 904	struct usb_device_descriptor *desc;
 905	int ret;
 906
 907	if (size > sizeof(*desc))
 908		return -EINVAL;
 909	desc = kmalloc(sizeof(*desc), GFP_NOIO);
 910	if (!desc)
 911		return -ENOMEM;
 912
 913	ret = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, size);
 914	if (ret >= 0)
 915		memcpy(&dev->descriptor, desc, size);
 916	kfree(desc);
 917	return ret;
 918}
 919
 920/**
 921 * usb_get_status - issues a GET_STATUS call
 922 * @dev: the device whose status is being checked
 923 * @type: USB_RECIP_*; for device, interface, or endpoint
 924 * @target: zero (for device), else interface or endpoint number
 925 * @data: pointer to two bytes of bitmap data
 926 * Context: !in_interrupt ()
 927 *
 928 * Returns device, interface, or endpoint status.  Normally only of
 929 * interest to see if the device is self powered, or has enabled the
 930 * remote wakeup facility; or whether a bulk or interrupt endpoint
 931 * is halted ("stalled").
 932 *
 933 * Bits in these status bitmaps are set using the SET_FEATURE request,
 934 * and cleared using the CLEAR_FEATURE request.  The usb_clear_halt()
 935 * function should be used to clear halt ("stall") status.
 936 *
 937 * This call is synchronous, and may not be used in an interrupt context.
 938 *
 939 * Returns 0 and the status value in *@data (in host byte order) on success,
 940 * or else the status code from the underlying usb_control_msg() call.
 941 */
 942int usb_get_status(struct usb_device *dev, int type, int target, void *data)
 943{
 944	int ret;
 945	__le16 *status = kmalloc(sizeof(*status), GFP_KERNEL);
 946
 947	if (!status)
 948		return -ENOMEM;
 949
 950	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
 951		USB_REQ_GET_STATUS, USB_DIR_IN | type, 0, target, status,
 952		sizeof(*status), USB_CTRL_GET_TIMEOUT);
 953
 954	if (ret == 2) {
 955		*(u16 *) data = le16_to_cpu(*status);
 956		ret = 0;
 957	} else if (ret >= 0) {
 958		ret = -EIO;
 959	}
 960	kfree(status);
 961	return ret;
 962}
 963EXPORT_SYMBOL_GPL(usb_get_status);
 964
 965/**
 966 * usb_clear_halt - tells device to clear endpoint halt/stall condition
 967 * @dev: device whose endpoint is halted
 968 * @pipe: endpoint "pipe" being cleared
 969 * Context: !in_interrupt ()
 970 *
 971 * This is used to clear halt conditions for bulk and interrupt endpoints,
 972 * as reported by URB completion status.  Endpoints that are halted are
 973 * sometimes referred to as being "stalled".  Such endpoints are unable
 974 * to transmit or receive data until the halt status is cleared.  Any URBs
 975 * queued for such an endpoint should normally be unlinked by the driver
 976 * before clearing the halt condition, as described in sections 5.7.5
 977 * and 5.8.5 of the USB 2.0 spec.
 978 *
 979 * Note that control and isochronous endpoints don't halt, although control
 980 * endpoints report "protocol stall" (for unsupported requests) using the
 981 * same status code used to report a true stall.
 982 *
 983 * This call is synchronous, and may not be used in an interrupt context.
 984 *
 985 * Return: Zero on success, or else the status code returned by the
 986 * underlying usb_control_msg() call.
 987 */
 988int usb_clear_halt(struct usb_device *dev, int pipe)
 989{
 990	int result;
 991	int endp = usb_pipeendpoint(pipe);
 992
 993	if (usb_pipein(pipe))
 994		endp |= USB_DIR_IN;
 995
 996	/* we don't care if it wasn't halted first. in fact some devices
 997	 * (like some ibmcam model 1 units) seem to expect hosts to make
 998	 * this request for iso endpoints, which can't halt!
 999	 */
1000	result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
1001		USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
1002		USB_ENDPOINT_HALT, endp, NULL, 0,
1003		USB_CTRL_SET_TIMEOUT);
1004
1005	/* don't un-halt or force to DATA0 except on success */
1006	if (result < 0)
1007		return result;
1008
1009	/* NOTE:  seems like Microsoft and Apple don't bother verifying
1010	 * the clear "took", so some devices could lock up if you check...
1011	 * such as the Hagiwara FlashGate DUAL.  So we won't bother.
1012	 *
1013	 * NOTE:  make sure the logic here doesn't diverge much from
1014	 * the copy in usb-storage, for as long as we need two copies.
1015	 */
1016
1017	usb_reset_endpoint(dev, endp);
1018
1019	return 0;
1020}
1021EXPORT_SYMBOL_GPL(usb_clear_halt);
1022
1023static int create_intf_ep_devs(struct usb_interface *intf)
1024{
1025	struct usb_device *udev = interface_to_usbdev(intf);
1026	struct usb_host_interface *alt = intf->cur_altsetting;
1027	int i;
1028
1029	if (intf->ep_devs_created || intf->unregistering)
1030		return 0;
1031
1032	for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1033		(void) usb_create_ep_devs(&intf->dev, &alt->endpoint[i], udev);
1034	intf->ep_devs_created = 1;
1035	return 0;
1036}
1037
1038static void remove_intf_ep_devs(struct usb_interface *intf)
1039{
1040	struct usb_host_interface *alt = intf->cur_altsetting;
1041	int i;
1042
1043	if (!intf->ep_devs_created)
1044		return;
1045
1046	for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1047		usb_remove_ep_devs(&alt->endpoint[i]);
1048	intf->ep_devs_created = 0;
1049}
1050
1051/**
1052 * usb_disable_endpoint -- Disable an endpoint by address
1053 * @dev: the device whose endpoint is being disabled
1054 * @epaddr: the endpoint's address.  Endpoint number for output,
1055 *	endpoint number + USB_DIR_IN for input
1056 * @reset_hardware: flag to erase any endpoint state stored in the
1057 *	controller hardware
1058 *
1059 * Disables the endpoint for URB submission and nukes all pending URBs.
1060 * If @reset_hardware is set then also deallocates hcd/hardware state
1061 * for the endpoint.
1062 */
1063void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr,
1064		bool reset_hardware)
1065{
1066	unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
1067	struct usb_host_endpoint *ep;
1068
1069	if (!dev)
1070		return;
1071
1072	if (usb_endpoint_out(epaddr)) {
1073		ep = dev->ep_out[epnum];
1074		if (reset_hardware)
1075			dev->ep_out[epnum] = NULL;
1076	} else {
1077		ep = dev->ep_in[epnum];
1078		if (reset_hardware)
1079			dev->ep_in[epnum] = NULL;
1080	}
1081	if (ep) {
1082		ep->enabled = 0;
1083		usb_hcd_flush_endpoint(dev, ep);
1084		if (reset_hardware)
1085			usb_hcd_disable_endpoint(dev, ep);
1086	}
1087}
1088
1089/**
1090 * usb_reset_endpoint - Reset an endpoint's state.
1091 * @dev: the device whose endpoint is to be reset
1092 * @epaddr: the endpoint's address.  Endpoint number for output,
1093 *	endpoint number + USB_DIR_IN for input
1094 *
1095 * Resets any host-side endpoint state such as the toggle bit,
1096 * sequence number or current window.
1097 */
1098void usb_reset_endpoint(struct usb_device *dev, unsigned int epaddr)
1099{
1100	unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
1101	struct usb_host_endpoint *ep;
1102
1103	if (usb_endpoint_out(epaddr))
1104		ep = dev->ep_out[epnum];
1105	else
1106		ep = dev->ep_in[epnum];
1107	if (ep)
1108		usb_hcd_reset_endpoint(dev, ep);
1109}
1110EXPORT_SYMBOL_GPL(usb_reset_endpoint);
1111
1112
1113/**
1114 * usb_disable_interface -- Disable all endpoints for an interface
1115 * @dev: the device whose interface is being disabled
1116 * @intf: pointer to the interface descriptor
1117 * @reset_hardware: flag to erase any endpoint state stored in the
1118 *	controller hardware
1119 *
1120 * Disables all the endpoints for the interface's current altsetting.
1121 */
1122void usb_disable_interface(struct usb_device *dev, struct usb_interface *intf,
1123		bool reset_hardware)
1124{
1125	struct usb_host_interface *alt = intf->cur_altsetting;
1126	int i;
1127
1128	for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
1129		usb_disable_endpoint(dev,
1130				alt->endpoint[i].desc.bEndpointAddress,
1131				reset_hardware);
1132	}
1133}
1134
1135/**
1136 * usb_disable_device - Disable all the endpoints for a USB device
1137 * @dev: the device whose endpoints are being disabled
1138 * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
1139 *
1140 * Disables all the device's endpoints, potentially including endpoint 0.
1141 * Deallocates hcd/hardware state for the endpoints (nuking all or most
1142 * pending urbs) and usbcore state for the interfaces, so that usbcore
1143 * must usb_set_configuration() before any interfaces could be used.
1144 */
1145void usb_disable_device(struct usb_device *dev, int skip_ep0)
1146{
1147	int i;
1148	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1149
1150	/* getting rid of interfaces will disconnect
1151	 * any drivers bound to them (a key side effect)
1152	 */
1153	if (dev->actconfig) {
1154		/*
1155		 * FIXME: In order to avoid self-deadlock involving the
1156		 * bandwidth_mutex, we have to mark all the interfaces
1157		 * before unregistering any of them.
1158		 */
1159		for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++)
1160			dev->actconfig->interface[i]->unregistering = 1;
1161
1162		for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
1163			struct usb_interface	*interface;
1164
1165			/* remove this interface if it has been registered */
1166			interface = dev->actconfig->interface[i];
1167			if (!device_is_registered(&interface->dev))
1168				continue;
1169			dev_dbg(&dev->dev, "unregistering interface %s\n",
1170				dev_name(&interface->dev));
1171			remove_intf_ep_devs(interface);
1172			device_del(&interface->dev);
1173		}
1174
1175		/* Now that the interfaces are unbound, nobody should
1176		 * try to access them.
1177		 */
1178		for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
1179			put_device(&dev->actconfig->interface[i]->dev);
1180			dev->actconfig->interface[i] = NULL;
1181		}
1182
1183		if (dev->usb2_hw_lpm_enabled == 1)
1184			usb_set_usb2_hardware_lpm(dev, 0);
1185		usb_unlocked_disable_lpm(dev);
1186		usb_disable_ltm(dev);
1187
1188		dev->actconfig = NULL;
1189		if (dev->state == USB_STATE_CONFIGURED)
1190			usb_set_device_state(dev, USB_STATE_ADDRESS);
1191	}
1192
1193	dev_dbg(&dev->dev, "%s nuking %s URBs\n", __func__,
1194		skip_ep0 ? "non-ep0" : "all");
1195	if (hcd->driver->check_bandwidth) {
1196		/* First pass: Cancel URBs, leave endpoint pointers intact. */
1197		for (i = skip_ep0; i < 16; ++i) {
1198			usb_disable_endpoint(dev, i, false);
1199			usb_disable_endpoint(dev, i + USB_DIR_IN, false);
1200		}
1201		/* Remove endpoints from the host controller internal state */
1202		mutex_lock(hcd->bandwidth_mutex);
1203		usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
1204		mutex_unlock(hcd->bandwidth_mutex);
1205		/* Second pass: remove endpoint pointers */
1206	}
1207	for (i = skip_ep0; i < 16; ++i) {
1208		usb_disable_endpoint(dev, i, true);
1209		usb_disable_endpoint(dev, i + USB_DIR_IN, true);
1210	}
1211}
1212
1213/**
1214 * usb_enable_endpoint - Enable an endpoint for USB communications
1215 * @dev: the device whose interface is being enabled
1216 * @ep: the endpoint
1217 * @reset_ep: flag to reset the endpoint state
1218 *
1219 * Resets the endpoint state if asked, and sets dev->ep_{in,out} pointers.
1220 * For control endpoints, both the input and output sides are handled.
1221 */
1222void usb_enable_endpoint(struct usb_device *dev, struct usb_host_endpoint *ep,
1223		bool reset_ep)
1224{
1225	int epnum = usb_endpoint_num(&ep->desc);
1226	int is_out = usb_endpoint_dir_out(&ep->desc);
1227	int is_control = usb_endpoint_xfer_control(&ep->desc);
1228
1229	if (reset_ep)
1230		usb_hcd_reset_endpoint(dev, ep);
1231	if (is_out || is_control)
1232		dev->ep_out[epnum] = ep;
1233	if (!is_out || is_control)
1234		dev->ep_in[epnum] = ep;
1235	ep->enabled = 1;
1236}
1237
1238/**
1239 * usb_enable_interface - Enable all the endpoints for an interface
1240 * @dev: the device whose interface is being enabled
1241 * @intf: pointer to the interface descriptor
1242 * @reset_eps: flag to reset the endpoints' state
1243 *
1244 * Enables all the endpoints for the interface's current altsetting.
1245 */
1246void usb_enable_interface(struct usb_device *dev,
1247		struct usb_interface *intf, bool reset_eps)
1248{
1249	struct usb_host_interface *alt = intf->cur_altsetting;
1250	int i;
1251
1252	for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1253		usb_enable_endpoint(dev, &alt->endpoint[i], reset_eps);
1254}
1255
1256/**
1257 * usb_set_interface - Makes a particular alternate setting be current
1258 * @dev: the device whose interface is being updated
1259 * @interface: the interface being updated
1260 * @alternate: the setting being chosen.
1261 * Context: !in_interrupt ()
1262 *
1263 * This is used to enable data transfers on interfaces that may not
1264 * be enabled by default.  Not all devices support such configurability.
1265 * Only the driver bound to an interface may change its setting.
1266 *
1267 * Within any given configuration, each interface may have several
1268 * alternative settings.  These are often used to control levels of
1269 * bandwidth consumption.  For example, the default setting for a high
1270 * speed interrupt endpoint may not send more than 64 bytes per microframe,
1271 * while interrupt transfers of up to 3KBytes per microframe are legal.
1272 * Also, isochronous endpoints may never be part of an
1273 * interface's default setting.  To access such bandwidth, alternate
1274 * interface settings must be made current.
1275 *
1276 * Note that in the Linux USB subsystem, bandwidth associated with
1277 * an endpoint in a given alternate setting is not reserved until an URB
1278 * is submitted that needs that bandwidth.  Some other operating systems
1279 * allocate bandwidth early, when a configuration is chosen.
1280 *
1281 * This call is synchronous, and may not be used in an interrupt context.
1282 * Also, drivers must not change altsettings while urbs are scheduled for
1283 * endpoints in that interface; all such urbs must first be completed
1284 * (perhaps forced by unlinking).
1285 *
1286 * Return: Zero on success, or else the status code returned by the
1287 * underlying usb_control_msg() call.
1288 */
1289int usb_set_interface(struct usb_device *dev, int interface, int alternate)
1290{
1291	struct usb_interface *iface;
1292	struct usb_host_interface *alt;
1293	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1294	int i, ret, manual = 0;
 
1295	unsigned int epaddr;
1296	unsigned int pipe;
1297
1298	if (dev->state == USB_STATE_SUSPENDED)
1299		return -EHOSTUNREACH;
1300
1301	iface = usb_ifnum_to_if(dev, interface);
1302	if (!iface) {
1303		dev_dbg(&dev->dev, "selecting invalid interface %d\n",
1304			interface);
1305		return -EINVAL;
1306	}
1307	if (iface->unregistering)
1308		return -ENODEV;
1309
1310	alt = usb_altnum_to_altsetting(iface, alternate);
1311	if (!alt) {
1312		dev_warn(&dev->dev, "selecting invalid altsetting %d\n",
1313			 alternate);
1314		return -EINVAL;
1315	}
1316
1317	/* Make sure we have enough bandwidth for this alternate interface.
1318	 * Remove the current alt setting and add the new alt setting.
1319	 */
1320	mutex_lock(hcd->bandwidth_mutex);
1321	/* Disable LPM, and re-enable it once the new alt setting is installed,
1322	 * so that the xHCI driver can recalculate the U1/U2 timeouts.
1323	 */
1324	if (usb_disable_lpm(dev)) {
1325		dev_err(&iface->dev, "%s Failed to disable LPM\n.", __func__);
1326		mutex_unlock(hcd->bandwidth_mutex);
1327		return -ENOMEM;
1328	}
1329	/* Changing alt-setting also frees any allocated streams */
1330	for (i = 0; i < iface->cur_altsetting->desc.bNumEndpoints; i++)
1331		iface->cur_altsetting->endpoint[i].streams = 0;
1332
1333	ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt);
1334	if (ret < 0) {
1335		dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n",
1336				alternate);
1337		usb_enable_lpm(dev);
1338		mutex_unlock(hcd->bandwidth_mutex);
1339		return ret;
1340	}
1341
1342	if (dev->quirks & USB_QUIRK_NO_SET_INTF)
1343		ret = -EPIPE;
1344	else
1345		ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
1346				   USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE,
1347				   alternate, interface, NULL, 0, 5000);
1348
1349	/* 9.4.10 says devices don't need this and are free to STALL the
1350	 * request if the interface only has one alternate setting.
1351	 */
1352	if (ret == -EPIPE && iface->num_altsetting == 1) {
1353		dev_dbg(&dev->dev,
1354			"manual set_interface for iface %d, alt %d\n",
1355			interface, alternate);
1356		manual = 1;
1357	} else if (ret < 0) {
1358		/* Re-instate the old alt setting */
1359		usb_hcd_alloc_bandwidth(dev, NULL, alt, iface->cur_altsetting);
1360		usb_enable_lpm(dev);
1361		mutex_unlock(hcd->bandwidth_mutex);
1362		return ret;
1363	}
1364	mutex_unlock(hcd->bandwidth_mutex);
1365
1366	/* FIXME drivers shouldn't need to replicate/bugfix the logic here
1367	 * when they implement async or easily-killable versions of this or
1368	 * other "should-be-internal" functions (like clear_halt).
1369	 * should hcd+usbcore postprocess control requests?
1370	 */
1371
1372	/* prevent submissions using previous endpoint settings */
1373	if (iface->cur_altsetting != alt) {
1374		remove_intf_ep_devs(iface);
1375		usb_remove_sysfs_intf_files(iface);
1376	}
1377	usb_disable_interface(dev, iface, true);
1378
1379	iface->cur_altsetting = alt;
1380
1381	/* Now that the interface is installed, re-enable LPM. */
1382	usb_unlocked_enable_lpm(dev);
1383
1384	/* If the interface only has one altsetting and the device didn't
1385	 * accept the request, we attempt to carry out the equivalent action
1386	 * by manually clearing the HALT feature for each endpoint in the
1387	 * new altsetting.
1388	 */
1389	if (manual) {
 
 
1390		for (i = 0; i < alt->desc.bNumEndpoints; i++) {
1391			epaddr = alt->endpoint[i].desc.bEndpointAddress;
1392			pipe = __create_pipe(dev,
1393					USB_ENDPOINT_NUMBER_MASK & epaddr) |
1394					(usb_endpoint_out(epaddr) ?
1395					USB_DIR_OUT : USB_DIR_IN);
1396
1397			usb_clear_halt(dev, pipe);
1398		}
1399	}
1400
1401	/* 9.1.1.5: reset toggles for all endpoints in the new altsetting
1402	 *
1403	 * Note:
1404	 * Despite EP0 is always present in all interfaces/AS, the list of
1405	 * endpoints from the descriptor does not contain EP0. Due to its
1406	 * omnipresence one might expect EP0 being considered "affected" by
1407	 * any SetInterface request and hence assume toggles need to be reset.
1408	 * However, EP0 toggles are re-synced for every individual transfer
1409	 * during the SETUP stage - hence EP0 toggles are "don't care" here.
1410	 * (Likewise, EP0 never "halts" on well designed devices.)
1411	 */
1412	usb_enable_interface(dev, iface, true);
1413	if (device_is_registered(&iface->dev)) {
1414		usb_create_sysfs_intf_files(iface);
1415		create_intf_ep_devs(iface);
1416	}
1417	return 0;
1418}
1419EXPORT_SYMBOL_GPL(usb_set_interface);
1420
1421/**
1422 * usb_reset_configuration - lightweight device reset
1423 * @dev: the device whose configuration is being reset
1424 *
1425 * This issues a standard SET_CONFIGURATION request to the device using
1426 * the current configuration.  The effect is to reset most USB-related
1427 * state in the device, including interface altsettings (reset to zero),
1428 * endpoint halts (cleared), and endpoint state (only for bulk and interrupt
1429 * endpoints).  Other usbcore state is unchanged, including bindings of
1430 * usb device drivers to interfaces.
1431 *
1432 * Because this affects multiple interfaces, avoid using this with composite
1433 * (multi-interface) devices.  Instead, the driver for each interface may
1434 * use usb_set_interface() on the interfaces it claims.  Be careful though;
1435 * some devices don't support the SET_INTERFACE request, and others won't
1436 * reset all the interface state (notably endpoint state).  Resetting the whole
1437 * configuration would affect other drivers' interfaces.
1438 *
1439 * The caller must own the device lock.
1440 *
1441 * Return: Zero on success, else a negative error code.
1442 */
1443int usb_reset_configuration(struct usb_device *dev)
1444{
1445	int			i, retval;
1446	struct usb_host_config	*config;
1447	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1448
1449	if (dev->state == USB_STATE_SUSPENDED)
1450		return -EHOSTUNREACH;
1451
1452	/* caller must have locked the device and must own
1453	 * the usb bus readlock (so driver bindings are stable);
1454	 * calls during probe() are fine
1455	 */
1456
1457	for (i = 1; i < 16; ++i) {
1458		usb_disable_endpoint(dev, i, true);
1459		usb_disable_endpoint(dev, i + USB_DIR_IN, true);
1460	}
1461
1462	config = dev->actconfig;
1463	retval = 0;
1464	mutex_lock(hcd->bandwidth_mutex);
1465	/* Disable LPM, and re-enable it once the configuration is reset, so
1466	 * that the xHCI driver can recalculate the U1/U2 timeouts.
1467	 */
1468	if (usb_disable_lpm(dev)) {
1469		dev_err(&dev->dev, "%s Failed to disable LPM\n.", __func__);
1470		mutex_unlock(hcd->bandwidth_mutex);
1471		return -ENOMEM;
1472	}
1473	/* Make sure we have enough bandwidth for each alternate setting 0 */
1474	for (i = 0; i < config->desc.bNumInterfaces; i++) {
1475		struct usb_interface *intf = config->interface[i];
1476		struct usb_host_interface *alt;
1477
1478		alt = usb_altnum_to_altsetting(intf, 0);
1479		if (!alt)
1480			alt = &intf->altsetting[0];
1481		if (alt != intf->cur_altsetting)
1482			retval = usb_hcd_alloc_bandwidth(dev, NULL,
1483					intf->cur_altsetting, alt);
1484		if (retval < 0)
1485			break;
1486	}
1487	/* If not, reinstate the old alternate settings */
1488	if (retval < 0) {
1489reset_old_alts:
1490		for (i--; i >= 0; i--) {
1491			struct usb_interface *intf = config->interface[i];
1492			struct usb_host_interface *alt;
1493
1494			alt = usb_altnum_to_altsetting(intf, 0);
1495			if (!alt)
1496				alt = &intf->altsetting[0];
1497			if (alt != intf->cur_altsetting)
1498				usb_hcd_alloc_bandwidth(dev, NULL,
1499						alt, intf->cur_altsetting);
1500		}
1501		usb_enable_lpm(dev);
1502		mutex_unlock(hcd->bandwidth_mutex);
1503		return retval;
1504	}
1505	retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
1506			USB_REQ_SET_CONFIGURATION, 0,
1507			config->desc.bConfigurationValue, 0,
1508			NULL, 0, USB_CTRL_SET_TIMEOUT);
1509	if (retval < 0)
1510		goto reset_old_alts;
1511	mutex_unlock(hcd->bandwidth_mutex);
1512
1513	/* re-init hc/hcd interface/endpoint state */
1514	for (i = 0; i < config->desc.bNumInterfaces; i++) {
1515		struct usb_interface *intf = config->interface[i];
1516		struct usb_host_interface *alt;
1517
1518		alt = usb_altnum_to_altsetting(intf, 0);
1519
1520		/* No altsetting 0?  We'll assume the first altsetting.
1521		 * We could use a GetInterface call, but if a device is
1522		 * so non-compliant that it doesn't have altsetting 0
1523		 * then I wouldn't trust its reply anyway.
1524		 */
1525		if (!alt)
1526			alt = &intf->altsetting[0];
1527
1528		if (alt != intf->cur_altsetting) {
1529			remove_intf_ep_devs(intf);
1530			usb_remove_sysfs_intf_files(intf);
1531		}
1532		intf->cur_altsetting = alt;
1533		usb_enable_interface(dev, intf, true);
1534		if (device_is_registered(&intf->dev)) {
1535			usb_create_sysfs_intf_files(intf);
1536			create_intf_ep_devs(intf);
1537		}
1538	}
1539	/* Now that the interfaces are installed, re-enable LPM. */
1540	usb_unlocked_enable_lpm(dev);
1541	return 0;
1542}
1543EXPORT_SYMBOL_GPL(usb_reset_configuration);
1544
1545static void usb_release_interface(struct device *dev)
1546{
1547	struct usb_interface *intf = to_usb_interface(dev);
1548	struct usb_interface_cache *intfc =
1549			altsetting_to_usb_interface_cache(intf->altsetting);
1550
1551	kref_put(&intfc->ref, usb_release_interface_cache);
1552	usb_put_dev(interface_to_usbdev(intf));
1553	kfree(intf);
1554}
1555
1556/*
1557 * usb_deauthorize_interface - deauthorize an USB interface
1558 *
1559 * @intf: USB interface structure
1560 */
1561void usb_deauthorize_interface(struct usb_interface *intf)
1562{
1563	struct device *dev = &intf->dev;
1564
1565	device_lock(dev->parent);
1566
1567	if (intf->authorized) {
1568		device_lock(dev);
1569		intf->authorized = 0;
1570		device_unlock(dev);
1571
1572		usb_forced_unbind_intf(intf);
1573	}
1574
1575	device_unlock(dev->parent);
1576}
1577
1578/*
1579 * usb_authorize_interface - authorize an USB interface
1580 *
1581 * @intf: USB interface structure
1582 */
1583void usb_authorize_interface(struct usb_interface *intf)
1584{
1585	struct device *dev = &intf->dev;
1586
1587	if (!intf->authorized) {
1588		device_lock(dev);
1589		intf->authorized = 1; /* authorize interface */
1590		device_unlock(dev);
1591	}
1592}
1593
1594static int usb_if_uevent(struct device *dev, struct kobj_uevent_env *env)
1595{
1596	struct usb_device *usb_dev;
1597	struct usb_interface *intf;
1598	struct usb_host_interface *alt;
1599
1600	intf = to_usb_interface(dev);
1601	usb_dev = interface_to_usbdev(intf);
1602	alt = intf->cur_altsetting;
1603
1604	if (add_uevent_var(env, "INTERFACE=%d/%d/%d",
1605		   alt->desc.bInterfaceClass,
1606		   alt->desc.bInterfaceSubClass,
1607		   alt->desc.bInterfaceProtocol))
1608		return -ENOMEM;
1609
1610	if (add_uevent_var(env,
1611		   "MODALIAS=usb:"
1612		   "v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02Xin%02X",
1613		   le16_to_cpu(usb_dev->descriptor.idVendor),
1614		   le16_to_cpu(usb_dev->descriptor.idProduct),
1615		   le16_to_cpu(usb_dev->descriptor.bcdDevice),
1616		   usb_dev->descriptor.bDeviceClass,
1617		   usb_dev->descriptor.bDeviceSubClass,
1618		   usb_dev->descriptor.bDeviceProtocol,
1619		   alt->desc.bInterfaceClass,
1620		   alt->desc.bInterfaceSubClass,
1621		   alt->desc.bInterfaceProtocol,
1622		   alt->desc.bInterfaceNumber))
1623		return -ENOMEM;
1624
1625	return 0;
1626}
1627
 
 
 
 
 
 
 
 
1628struct device_type usb_if_device_type = {
1629	.name =		"usb_interface",
1630	.release =	usb_release_interface,
1631	.uevent =	usb_if_uevent,
1632};
1633
1634static struct usb_interface_assoc_descriptor *find_iad(struct usb_device *dev,
1635						struct usb_host_config *config,
1636						u8 inum)
1637{
1638	struct usb_interface_assoc_descriptor *retval = NULL;
1639	struct usb_interface_assoc_descriptor *intf_assoc;
1640	int first_intf;
1641	int last_intf;
1642	int i;
1643
1644	for (i = 0; (i < USB_MAXIADS && config->intf_assoc[i]); i++) {
1645		intf_assoc = config->intf_assoc[i];
1646		if (intf_assoc->bInterfaceCount == 0)
1647			continue;
1648
1649		first_intf = intf_assoc->bFirstInterface;
1650		last_intf = first_intf + (intf_assoc->bInterfaceCount - 1);
1651		if (inum >= first_intf && inum <= last_intf) {
1652			if (!retval)
1653				retval = intf_assoc;
1654			else
1655				dev_err(&dev->dev, "Interface #%d referenced"
1656					" by multiple IADs\n", inum);
1657		}
1658	}
1659
1660	return retval;
1661}
1662
1663
1664/*
1665 * Internal function to queue a device reset
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1666 * See usb_queue_reset_device() for more details
1667 */
1668static void __usb_queue_reset_device(struct work_struct *ws)
1669{
1670	int rc;
1671	struct usb_interface *iface =
1672		container_of(ws, struct usb_interface, reset_ws);
1673	struct usb_device *udev = interface_to_usbdev(iface);
1674
1675	rc = usb_lock_device_for_reset(udev, iface);
1676	if (rc >= 0) {
 
1677		usb_reset_device(udev);
 
1678		usb_unlock_device(udev);
1679	}
1680	usb_put_intf(iface);	/* Undo _get_ in usb_queue_reset_device() */
1681}
1682
1683
1684/*
1685 * usb_set_configuration - Makes a particular device setting be current
1686 * @dev: the device whose configuration is being updated
1687 * @configuration: the configuration being chosen.
1688 * Context: !in_interrupt(), caller owns the device lock
1689 *
1690 * This is used to enable non-default device modes.  Not all devices
1691 * use this kind of configurability; many devices only have one
1692 * configuration.
1693 *
1694 * @configuration is the value of the configuration to be installed.
1695 * According to the USB spec (e.g. section 9.1.1.5), configuration values
1696 * must be non-zero; a value of zero indicates that the device in
1697 * unconfigured.  However some devices erroneously use 0 as one of their
1698 * configuration values.  To help manage such devices, this routine will
1699 * accept @configuration = -1 as indicating the device should be put in
1700 * an unconfigured state.
1701 *
1702 * USB device configurations may affect Linux interoperability,
1703 * power consumption and the functionality available.  For example,
1704 * the default configuration is limited to using 100mA of bus power,
1705 * so that when certain device functionality requires more power,
1706 * and the device is bus powered, that functionality should be in some
1707 * non-default device configuration.  Other device modes may also be
1708 * reflected as configuration options, such as whether two ISDN
1709 * channels are available independently; and choosing between open
1710 * standard device protocols (like CDC) or proprietary ones.
1711 *
1712 * Note that a non-authorized device (dev->authorized == 0) will only
1713 * be put in unconfigured mode.
1714 *
1715 * Note that USB has an additional level of device configurability,
1716 * associated with interfaces.  That configurability is accessed using
1717 * usb_set_interface().
1718 *
1719 * This call is synchronous. The calling context must be able to sleep,
1720 * must own the device lock, and must not hold the driver model's USB
1721 * bus mutex; usb interface driver probe() methods cannot use this routine.
1722 *
1723 * Returns zero on success, or else the status code returned by the
1724 * underlying call that failed.  On successful completion, each interface
1725 * in the original device configuration has been destroyed, and each one
1726 * in the new configuration has been probed by all relevant usb device
1727 * drivers currently known to the kernel.
1728 */
1729int usb_set_configuration(struct usb_device *dev, int configuration)
1730{
1731	int i, ret;
1732	struct usb_host_config *cp = NULL;
1733	struct usb_interface **new_interfaces = NULL;
1734	struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1735	int n, nintf;
1736
1737	if (dev->authorized == 0 || configuration == -1)
1738		configuration = 0;
1739	else {
1740		for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
1741			if (dev->config[i].desc.bConfigurationValue ==
1742					configuration) {
1743				cp = &dev->config[i];
1744				break;
1745			}
1746		}
1747	}
1748	if ((!cp && configuration != 0))
1749		return -EINVAL;
1750
1751	/* The USB spec says configuration 0 means unconfigured.
1752	 * But if a device includes a configuration numbered 0,
1753	 * we will accept it as a correctly configured state.
1754	 * Use -1 if you really want to unconfigure the device.
1755	 */
1756	if (cp && configuration == 0)
1757		dev_warn(&dev->dev, "config 0 descriptor??\n");
1758
1759	/* Allocate memory for new interfaces before doing anything else,
1760	 * so that if we run out then nothing will have changed. */
1761	n = nintf = 0;
1762	if (cp) {
1763		nintf = cp->desc.bNumInterfaces;
1764		new_interfaces = kmalloc(nintf * sizeof(*new_interfaces),
1765				GFP_NOIO);
1766		if (!new_interfaces) {
1767			dev_err(&dev->dev, "Out of memory\n");
1768			return -ENOMEM;
1769		}
1770
1771		for (; n < nintf; ++n) {
1772			new_interfaces[n] = kzalloc(
1773					sizeof(struct usb_interface),
1774					GFP_NOIO);
1775			if (!new_interfaces[n]) {
1776				dev_err(&dev->dev, "Out of memory\n");
1777				ret = -ENOMEM;
1778free_interfaces:
1779				while (--n >= 0)
1780					kfree(new_interfaces[n]);
1781				kfree(new_interfaces);
1782				return ret;
1783			}
1784		}
1785
1786		i = dev->bus_mA - usb_get_max_power(dev, cp);
1787		if (i < 0)
1788			dev_warn(&dev->dev, "new config #%d exceeds power "
1789					"limit by %dmA\n",
1790					configuration, -i);
1791	}
1792
1793	/* Wake up the device so we can send it the Set-Config request */
1794	ret = usb_autoresume_device(dev);
1795	if (ret)
1796		goto free_interfaces;
1797
1798	/* if it's already configured, clear out old state first.
1799	 * getting rid of old interfaces means unbinding their drivers.
1800	 */
1801	if (dev->state != USB_STATE_ADDRESS)
1802		usb_disable_device(dev, 1);	/* Skip ep0 */
1803
1804	/* Get rid of pending async Set-Config requests for this device */
1805	cancel_async_set_config(dev);
1806
1807	/* Make sure we have bandwidth (and available HCD resources) for this
1808	 * configuration.  Remove endpoints from the schedule if we're dropping
1809	 * this configuration to set configuration 0.  After this point, the
1810	 * host controller will not allow submissions to dropped endpoints.  If
1811	 * this call fails, the device state is unchanged.
1812	 */
1813	mutex_lock(hcd->bandwidth_mutex);
1814	/* Disable LPM, and re-enable it once the new configuration is
1815	 * installed, so that the xHCI driver can recalculate the U1/U2
1816	 * timeouts.
1817	 */
1818	if (dev->actconfig && usb_disable_lpm(dev)) {
1819		dev_err(&dev->dev, "%s Failed to disable LPM\n.", __func__);
1820		mutex_unlock(hcd->bandwidth_mutex);
1821		ret = -ENOMEM;
1822		goto free_interfaces;
1823	}
1824	ret = usb_hcd_alloc_bandwidth(dev, cp, NULL, NULL);
1825	if (ret < 0) {
1826		if (dev->actconfig)
1827			usb_enable_lpm(dev);
1828		mutex_unlock(hcd->bandwidth_mutex);
1829		usb_autosuspend_device(dev);
1830		goto free_interfaces;
1831	}
1832
1833	/*
1834	 * Initialize the new interface structures and the
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1835	 * hc/hcd/usbcore interface/endpoint state.
1836	 */
1837	for (i = 0; i < nintf; ++i) {
1838		struct usb_interface_cache *intfc;
1839		struct usb_interface *intf;
1840		struct usb_host_interface *alt;
1841
1842		cp->interface[i] = intf = new_interfaces[i];
1843		intfc = cp->intf_cache[i];
1844		intf->altsetting = intfc->altsetting;
1845		intf->num_altsetting = intfc->num_altsetting;
1846		intf->authorized = !!HCD_INTF_AUTHORIZED(hcd);
1847		kref_get(&intfc->ref);
1848
1849		alt = usb_altnum_to_altsetting(intf, 0);
1850
1851		/* No altsetting 0?  We'll assume the first altsetting.
1852		 * We could use a GetInterface call, but if a device is
1853		 * so non-compliant that it doesn't have altsetting 0
1854		 * then I wouldn't trust its reply anyway.
1855		 */
1856		if (!alt)
1857			alt = &intf->altsetting[0];
1858
1859		intf->intf_assoc =
1860			find_iad(dev, cp, alt->desc.bInterfaceNumber);
1861		intf->cur_altsetting = alt;
1862		usb_enable_interface(dev, intf, true);
1863		intf->dev.parent = &dev->dev;
1864		intf->dev.driver = NULL;
1865		intf->dev.bus = &usb_bus_type;
1866		intf->dev.type = &usb_if_device_type;
1867		intf->dev.groups = usb_interface_groups;
1868		intf->dev.dma_mask = dev->dev.dma_mask;
1869		INIT_WORK(&intf->reset_ws, __usb_queue_reset_device);
1870		intf->minor = -1;
1871		device_initialize(&intf->dev);
1872		pm_runtime_no_callbacks(&intf->dev);
1873		dev_set_name(&intf->dev, "%d-%s:%d.%d",
1874			dev->bus->busnum, dev->devpath,
1875			configuration, alt->desc.bInterfaceNumber);
1876		usb_get_dev(dev);
1877	}
1878	kfree(new_interfaces);
1879
1880	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
1881			      USB_REQ_SET_CONFIGURATION, 0, configuration, 0,
1882			      NULL, 0, USB_CTRL_SET_TIMEOUT);
1883	if (ret < 0 && cp) {
1884		/*
1885		 * All the old state is gone, so what else can we do?
1886		 * The device is probably useless now anyway.
1887		 */
1888		usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
1889		for (i = 0; i < nintf; ++i) {
1890			usb_disable_interface(dev, cp->interface[i], true);
1891			put_device(&cp->interface[i]->dev);
1892			cp->interface[i] = NULL;
1893		}
1894		cp = NULL;
1895	}
1896
1897	dev->actconfig = cp;
1898	mutex_unlock(hcd->bandwidth_mutex);
1899
1900	if (!cp) {
1901		usb_set_device_state(dev, USB_STATE_ADDRESS);
1902
1903		/* Leave LPM disabled while the device is unconfigured. */
1904		usb_autosuspend_device(dev);
1905		return ret;
1906	}
1907	usb_set_device_state(dev, USB_STATE_CONFIGURED);
1908
1909	if (cp->string == NULL &&
1910			!(dev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS))
1911		cp->string = usb_cache_string(dev, cp->desc.iConfiguration);
1912
1913	/* Now that the interfaces are installed, re-enable LPM. */
1914	usb_unlocked_enable_lpm(dev);
1915	/* Enable LTM if it was turned off by usb_disable_device. */
1916	usb_enable_ltm(dev);
1917
1918	/* Now that all the interfaces are set up, register them
1919	 * to trigger binding of drivers to interfaces.  probe()
1920	 * routines may install different altsettings and may
1921	 * claim() any interfaces not yet bound.  Many class drivers
1922	 * need that: CDC, audio, video, etc.
1923	 */
1924	for (i = 0; i < nintf; ++i) {
1925		struct usb_interface *intf = cp->interface[i];
1926
1927		dev_dbg(&dev->dev,
1928			"adding %s (config #%d, interface %d)\n",
1929			dev_name(&intf->dev), configuration,
1930			intf->cur_altsetting->desc.bInterfaceNumber);
1931		device_enable_async_suspend(&intf->dev);
1932		ret = device_add(&intf->dev);
1933		if (ret != 0) {
1934			dev_err(&dev->dev, "device_add(%s) --> %d\n",
1935				dev_name(&intf->dev), ret);
1936			continue;
1937		}
1938		create_intf_ep_devs(intf);
1939	}
1940
1941	usb_autosuspend_device(dev);
1942	return 0;
1943}
1944EXPORT_SYMBOL_GPL(usb_set_configuration);
1945
1946static LIST_HEAD(set_config_list);
1947static DEFINE_SPINLOCK(set_config_lock);
1948
1949struct set_config_request {
1950	struct usb_device	*udev;
1951	int			config;
1952	struct work_struct	work;
1953	struct list_head	node;
1954};
1955
1956/* Worker routine for usb_driver_set_configuration() */
1957static void driver_set_config_work(struct work_struct *work)
1958{
1959	struct set_config_request *req =
1960		container_of(work, struct set_config_request, work);
1961	struct usb_device *udev = req->udev;
1962
1963	usb_lock_device(udev);
1964	spin_lock(&set_config_lock);
1965	list_del(&req->node);
1966	spin_unlock(&set_config_lock);
1967
1968	if (req->config >= -1)		/* Is req still valid? */
1969		usb_set_configuration(udev, req->config);
1970	usb_unlock_device(udev);
1971	usb_put_dev(udev);
1972	kfree(req);
1973}
1974
1975/* Cancel pending Set-Config requests for a device whose configuration
1976 * was just changed
1977 */
1978static void cancel_async_set_config(struct usb_device *udev)
1979{
1980	struct set_config_request *req;
1981
1982	spin_lock(&set_config_lock);
1983	list_for_each_entry(req, &set_config_list, node) {
1984		if (req->udev == udev)
1985			req->config = -999;	/* Mark as cancelled */
1986	}
1987	spin_unlock(&set_config_lock);
1988}
1989
1990/**
1991 * usb_driver_set_configuration - Provide a way for drivers to change device configurations
1992 * @udev: the device whose configuration is being updated
1993 * @config: the configuration being chosen.
1994 * Context: In process context, must be able to sleep
1995 *
1996 * Device interface drivers are not allowed to change device configurations.
1997 * This is because changing configurations will destroy the interface the
1998 * driver is bound to and create new ones; it would be like a floppy-disk
1999 * driver telling the computer to replace the floppy-disk drive with a
2000 * tape drive!
2001 *
2002 * Still, in certain specialized circumstances the need may arise.  This
2003 * routine gets around the normal restrictions by using a work thread to
2004 * submit the change-config request.
2005 *
2006 * Return: 0 if the request was successfully queued, error code otherwise.
2007 * The caller has no way to know whether the queued request will eventually
2008 * succeed.
2009 */
2010int usb_driver_set_configuration(struct usb_device *udev, int config)
2011{
2012	struct set_config_request *req;
2013
2014	req = kmalloc(sizeof(*req), GFP_KERNEL);
2015	if (!req)
2016		return -ENOMEM;
2017	req->udev = udev;
2018	req->config = config;
2019	INIT_WORK(&req->work, driver_set_config_work);
2020
2021	spin_lock(&set_config_lock);
2022	list_add(&req->node, &set_config_list);
2023	spin_unlock(&set_config_lock);
2024
2025	usb_get_dev(udev);
2026	schedule_work(&req->work);
2027	return 0;
2028}
2029EXPORT_SYMBOL_GPL(usb_driver_set_configuration);