2 * message.c - synchronous message handling
5 #include <linux/pci.h> /* for scatterlist macros */
7 #include <linux/module.h>
8 #include <linux/slab.h>
9 #include <linux/init.h>
11 #include <linux/timer.h>
12 #include <linux/ctype.h>
13 #include <linux/nls.h>
14 #include <linux/device.h>
15 #include <linux/scatterlist.h>
16 #include <linux/usb/quirks.h>
17 #include <linux/usb/hcd.h> /* for usbcore internals */
18 #include <asm/byteorder.h>
22 static void cancel_async_set_config(struct usb_device *udev);
25 struct completion done;
29 static void usb_api_blocking_completion(struct urb *urb)
31 struct api_context *ctx = urb->context;
33 ctx->status = urb->status;
39 * Starts urb and waits for completion or timeout. Note that this call
40 * is NOT interruptible. Many device driver i/o requests should be
41 * interruptible and therefore these drivers should implement their
42 * own interruptible routines.
44 static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)
46 struct api_context ctx;
50 init_completion(&ctx.done);
52 urb->actual_length = 0;
53 retval = usb_submit_urb(urb, GFP_NOIO);
57 expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT;
58 if (!wait_for_completion_timeout(&ctx.done, expire)) {
60 retval = (ctx.status == -ENOENT ? -ETIMEDOUT : ctx.status);
62 dev_dbg(&urb->dev->dev,
63 "%s timed out on ep%d%s len=%u/%u\n",
65 usb_endpoint_num(&urb->ep->desc),
66 usb_urb_dir_in(urb) ? "in" : "out",
68 urb->transfer_buffer_length);
73 *actual_length = urb->actual_length;
79 /*-------------------------------------------------------------------*/
80 /* returns status (negative) or length (positive) */
81 static int usb_internal_control_msg(struct usb_device *usb_dev,
83 struct usb_ctrlrequest *cmd,
84 void *data, int len, int timeout)
90 urb = usb_alloc_urb(0, GFP_NOIO);
94 usb_fill_control_urb(urb, usb_dev, pipe, (unsigned char *)cmd, data,
95 len, usb_api_blocking_completion, NULL);
97 retv = usb_start_wait_urb(urb, timeout, &length);
105 * usb_control_msg - Builds a control urb, sends it off and waits for completion
106 * @dev: pointer to the usb device to send the message to
107 * @pipe: endpoint "pipe" to send the message to
108 * @request: USB message request value
109 * @requesttype: USB message request type value
110 * @value: USB message value
111 * @index: USB message index value
112 * @data: pointer to the data to send
113 * @size: length in bytes of the data to send
114 * @timeout: time in msecs to wait for the message to complete before timing
115 * out (if 0 the wait is forever)
117 * Context: !in_interrupt ()
119 * This function sends a simple control message to a specified endpoint and
120 * waits for the message to complete, or timeout.
122 * If successful, it returns the number of bytes transferred, otherwise a
123 * negative error number.
125 * Don't use this function from within an interrupt context, like a bottom half
126 * handler. If you need an asynchronous message, or need to send a message
127 * from within interrupt context, use usb_submit_urb().
128 * If a thread in your driver uses this call, make sure your disconnect()
129 * method can wait for it to complete. Since you don't have a handle on the
130 * URB used, you can't cancel the request.
132 int usb_control_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
133 __u8 requesttype, __u16 value, __u16 index, void *data,
134 __u16 size, int timeout)
136 struct usb_ctrlrequest *dr;
139 dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_NOIO);
143 dr->bRequestType = requesttype;
144 dr->bRequest = request;
145 dr->wValue = cpu_to_le16(value);
146 dr->wIndex = cpu_to_le16(index);
147 dr->wLength = cpu_to_le16(size);
149 ret = usb_internal_control_msg(dev, pipe, dr, data, size, timeout);
155 EXPORT_SYMBOL_GPL(usb_control_msg);
158 * usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for completion
159 * @usb_dev: pointer to the usb device to send the message to
160 * @pipe: endpoint "pipe" to send the message to
161 * @data: pointer to the data to send
162 * @len: length in bytes of the data to send
163 * @actual_length: pointer to a location to put the actual length transferred
165 * @timeout: time in msecs to wait for the message to complete before
166 * timing out (if 0 the wait is forever)
168 * Context: !in_interrupt ()
170 * This function sends a simple interrupt message to a specified endpoint and
171 * waits for the message to complete, or timeout.
173 * If successful, it returns 0, otherwise a negative error number. The number
174 * of actual bytes transferred will be stored in the actual_length paramater.
176 * Don't use this function from within an interrupt context, like a bottom half
177 * handler. If you need an asynchronous message, or need to send a message
178 * from within interrupt context, use usb_submit_urb() If a thread in your
179 * driver uses this call, make sure your disconnect() method can wait for it to
180 * complete. Since you don't have a handle on the URB used, you can't cancel
183 int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe,
184 void *data, int len, int *actual_length, int timeout)
186 return usb_bulk_msg(usb_dev, pipe, data, len, actual_length, timeout);
188 EXPORT_SYMBOL_GPL(usb_interrupt_msg);
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
198 * @timeout: time in msecs to wait for the message to complete before
199 * timing out (if 0 the wait is forever)
201 * Context: !in_interrupt ()
203 * This function sends a simple bulk message to a specified endpoint
204 * and waits for the message to complete, or timeout.
206 * If successful, it returns 0, otherwise a negative error number. The number
207 * of actual bytes transferred will be stored in the actual_length paramater.
209 * Don't use this function from within an interrupt context, like a bottom half
210 * handler. If you need an asynchronous message, or need to send a message
211 * from within interrupt context, use usb_submit_urb() If a thread in your
212 * driver uses this call, make sure your disconnect() method can wait for it to
213 * complete. Since you don't have a handle on the URB used, you can't cancel
216 * Because there is no usb_interrupt_msg() and no USBDEVFS_INTERRUPT ioctl,
217 * users are forced to abuse this routine by using it to submit URBs for
218 * interrupt endpoints. We will take the liberty of creating an interrupt URB
219 * (with the default interval) if the target is an interrupt endpoint.
221 int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe,
222 void *data, int len, int *actual_length, int timeout)
225 struct usb_host_endpoint *ep;
227 ep = usb_pipe_endpoint(usb_dev, pipe);
231 urb = usb_alloc_urb(0, GFP_KERNEL);
235 if ((ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
236 USB_ENDPOINT_XFER_INT) {
237 pipe = (pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30);
238 usb_fill_int_urb(urb, usb_dev, pipe, data, len,
239 usb_api_blocking_completion, NULL,
242 usb_fill_bulk_urb(urb, usb_dev, pipe, data, len,
243 usb_api_blocking_completion, NULL);
245 return usb_start_wait_urb(urb, timeout, actual_length);
247 EXPORT_SYMBOL_GPL(usb_bulk_msg);
249 /*-------------------------------------------------------------------*/
251 static void sg_clean(struct usb_sg_request *io)
254 while (io->entries--)
255 usb_free_urb(io->urbs [io->entries]);
262 static void sg_complete(struct urb *urb)
264 struct usb_sg_request *io = urb->context;
265 int status = urb->status;
267 spin_lock(&io->lock);
269 /* In 2.5 we require hcds' endpoint queues not to progress after fault
270 * reports, until the completion callback (this!) returns. That lets
271 * device driver code (like this routine) unlink queued urbs first,
272 * if it needs to, since the HC won't work on them at all. So it's
273 * not possible for page N+1 to overwrite page N, and so on.
275 * That's only for "hard" faults; "soft" faults (unlinks) sometimes
276 * complete before the HCD can get requests away from hardware,
277 * though never during cleanup after a hard fault.
280 && (io->status != -ECONNRESET
281 || status != -ECONNRESET)
282 && urb->actual_length) {
283 dev_err(io->dev->bus->controller,
284 "dev %s ep%d%s scatterlist error %d/%d\n",
286 usb_endpoint_num(&urb->ep->desc),
287 usb_urb_dir_in(urb) ? "in" : "out",
292 if (io->status == 0 && status && status != -ECONNRESET) {
293 int i, found, retval;
297 /* the previous urbs, and this one, completed already.
298 * unlink pending urbs so they won't rx/tx bad data.
299 * careful: unlink can sometimes be synchronous...
301 spin_unlock(&io->lock);
302 for (i = 0, found = 0; i < io->entries; i++) {
303 if (!io->urbs [i] || !io->urbs [i]->dev)
306 retval = usb_unlink_urb(io->urbs [i]);
307 if (retval != -EINPROGRESS &&
311 dev_err(&io->dev->dev,
312 "%s, unlink --> %d\n",
314 } else if (urb == io->urbs [i])
317 spin_lock(&io->lock);
320 /* on the last completion, signal usb_sg_wait() */
321 io->bytes += urb->actual_length;
324 complete(&io->complete);
326 spin_unlock(&io->lock);
331 * usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request
332 * @io: request block being initialized. until usb_sg_wait() returns,
333 * treat this as a pointer to an opaque block of memory,
334 * @dev: the usb device that will send or receive the data
335 * @pipe: endpoint "pipe" used to transfer the data
336 * @period: polling rate for interrupt endpoints, in frames or
337 * (for high speed endpoints) microframes; ignored for bulk
338 * @sg: scatterlist entries
339 * @nents: how many entries in the scatterlist
340 * @length: how many bytes to send from the scatterlist, or zero to
341 * send every byte identified in the list.
342 * @mem_flags: SLAB_* flags affecting memory allocations in this call
344 * Returns zero for success, else a negative errno value. This initializes a
345 * scatter/gather request, allocating resources such as I/O mappings and urb
346 * memory (except maybe memory used by USB controller drivers).
348 * The request must be issued using usb_sg_wait(), which waits for the I/O to
349 * complete (or to be canceled) and then cleans up all resources allocated by
352 * The request may be canceled with usb_sg_cancel(), either before or after
353 * usb_sg_wait() is called.
355 int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
356 unsigned pipe, unsigned period, struct scatterlist *sg,
357 int nents, size_t length, gfp_t mem_flags)
363 if (!io || !dev || !sg
364 || usb_pipecontrol(pipe)
365 || usb_pipeisoc(pipe)
369 spin_lock_init(&io->lock);
373 if (dev->bus->sg_tablesize > 0) {
381 /* initialize all the urbs we'll use */
382 io->urbs = kmalloc(io->entries * sizeof *io->urbs, mem_flags);
386 urb_flags = URB_NO_INTERRUPT;
387 if (usb_pipein(pipe))
388 urb_flags |= URB_SHORT_NOT_OK;
390 for_each_sg(sg, sg, io->entries, i) {
394 urb = usb_alloc_urb(0, mem_flags);
403 urb->interval = period;
404 urb->transfer_flags = urb_flags;
405 urb->complete = sg_complete;
410 /* There is no single transfer buffer */
411 urb->transfer_buffer = NULL;
412 urb->num_sgs = nents;
414 /* A length of zero means transfer the whole sg list */
417 struct scatterlist *sg2;
420 for_each_sg(sg, sg2, nents, j)
425 * Some systems can't use DMA; they use PIO instead.
426 * For their sakes, transfer_buffer is set whenever
429 if (!PageHighMem(sg_page(sg)))
430 urb->transfer_buffer = sg_virt(sg);
432 urb->transfer_buffer = NULL;
436 len = min_t(size_t, len, length);
442 urb->transfer_buffer_length = len;
444 io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT;
446 /* transaction state */
447 io->count = io->entries;
450 init_completion(&io->complete);
457 EXPORT_SYMBOL_GPL(usb_sg_init);
460 * usb_sg_wait - synchronously execute scatter/gather request
461 * @io: request block handle, as initialized with usb_sg_init().
462 * some fields become accessible when this call returns.
463 * Context: !in_interrupt ()
465 * This function blocks until the specified I/O operation completes. It
466 * leverages the grouping of the related I/O requests to get good transfer
467 * rates, by queueing the requests. At higher speeds, such queuing can
468 * significantly improve USB throughput.
470 * There are three kinds of completion for this function.
471 * (1) success, where io->status is zero. The number of io->bytes
472 * transferred is as requested.
473 * (2) error, where io->status is a negative errno value. The number
474 * of io->bytes transferred before the error is usually less
475 * than requested, and can be nonzero.
476 * (3) cancellation, a type of error with status -ECONNRESET that
477 * is initiated by usb_sg_cancel().
479 * When this function returns, all memory allocated through usb_sg_init() or
480 * this call will have been freed. The request block parameter may still be
481 * passed to usb_sg_cancel(), or it may be freed. It could also be
482 * reinitialized and then reused.
484 * Data Transfer Rates:
486 * Bulk transfers are valid for full or high speed endpoints.
487 * The best full speed data rate is 19 packets of 64 bytes each
488 * per frame, or 1216 bytes per millisecond.
489 * The best high speed data rate is 13 packets of 512 bytes each
490 * per microframe, or 52 KBytes per millisecond.
492 * The reason to use interrupt transfers through this API would most likely
493 * be to reserve high speed bandwidth, where up to 24 KBytes per millisecond
494 * could be transferred. That capability is less useful for low or full
495 * speed interrupt endpoints, which allow at most one packet per millisecond,
496 * of at most 8 or 64 bytes (respectively).
498 * It is not necessary to call this function to reserve bandwidth for devices
499 * under an xHCI host controller, as the bandwidth is reserved when the
500 * configuration or interface alt setting is selected.
502 void usb_sg_wait(struct usb_sg_request *io)
505 int entries = io->entries;
507 /* queue the urbs. */
508 spin_lock_irq(&io->lock);
510 while (i < entries && !io->status) {
513 io->urbs[i]->dev = io->dev;
514 retval = usb_submit_urb(io->urbs [i], GFP_ATOMIC);
516 /* after we submit, let completions or cancelations fire;
517 * we handshake using io->status.
519 spin_unlock_irq(&io->lock);
521 /* maybe we retrying will recover */
522 case -ENXIO: /* hc didn't queue this one */
529 /* no error? continue immediately.
531 * NOTE: to work better with UHCI (4K I/O buffer may
532 * need 3K of TDs) it may be good to limit how many
533 * URBs are queued at once; N milliseconds?
540 /* fail any uncompleted urbs */
542 io->urbs[i]->status = retval;
543 dev_dbg(&io->dev->dev, "%s, submit --> %d\n",
547 spin_lock_irq(&io->lock);
548 if (retval && (io->status == 0 || io->status == -ECONNRESET))
551 io->count -= entries - i;
553 complete(&io->complete);
554 spin_unlock_irq(&io->lock);
556 /* OK, yes, this could be packaged as non-blocking.
557 * So could the submit loop above ... but it's easier to
558 * solve neither problem than to solve both!
560 wait_for_completion(&io->complete);
564 EXPORT_SYMBOL_GPL(usb_sg_wait);
567 * usb_sg_cancel - stop scatter/gather i/o issued by usb_sg_wait()
568 * @io: request block, initialized with usb_sg_init()
570 * This stops a request after it has been started by usb_sg_wait().
571 * It can also prevents one initialized by usb_sg_init() from starting,
572 * so that call just frees resources allocated to the request.
574 void usb_sg_cancel(struct usb_sg_request *io)
578 spin_lock_irqsave(&io->lock, flags);
580 /* shut everything down, if it didn't already */
584 io->status = -ECONNRESET;
585 spin_unlock(&io->lock);
586 for (i = 0; i < io->entries; i++) {
589 if (!io->urbs [i]->dev)
591 retval = usb_unlink_urb(io->urbs [i]);
592 if (retval != -EINPROGRESS
596 dev_warn(&io->dev->dev, "%s, unlink --> %d\n",
599 spin_lock(&io->lock);
601 spin_unlock_irqrestore(&io->lock, flags);
603 EXPORT_SYMBOL_GPL(usb_sg_cancel);
605 /*-------------------------------------------------------------------*/
608 * usb_get_descriptor - issues a generic GET_DESCRIPTOR request
609 * @dev: the device whose descriptor is being retrieved
610 * @type: the descriptor type (USB_DT_*)
611 * @index: the number of the descriptor
612 * @buf: where to put the descriptor
613 * @size: how big is "buf"?
614 * Context: !in_interrupt ()
616 * Gets a USB descriptor. Convenience functions exist to simplify
617 * getting some types of descriptors. Use
618 * usb_get_string() or usb_string() for USB_DT_STRING.
619 * Device (USB_DT_DEVICE) and configuration descriptors (USB_DT_CONFIG)
620 * are part of the device structure.
621 * In addition to a number of USB-standard descriptors, some
622 * devices also use class-specific or vendor-specific descriptors.
624 * This call is synchronous, and may not be used in an interrupt context.
626 * Returns the number of bytes received on success, or else the status code
627 * returned by the underlying usb_control_msg() call.
629 int usb_get_descriptor(struct usb_device *dev, unsigned char type,
630 unsigned char index, void *buf, int size)
635 memset(buf, 0, size); /* Make sure we parse really received data */
637 for (i = 0; i < 3; ++i) {
638 /* retry on length 0 or error; some devices are flakey */
639 result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
640 USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
641 (type << 8) + index, 0, buf, size,
642 USB_CTRL_GET_TIMEOUT);
643 if (result <= 0 && result != -ETIMEDOUT)
645 if (result > 1 && ((u8 *)buf)[1] != type) {
653 EXPORT_SYMBOL_GPL(usb_get_descriptor);
656 * usb_get_string - gets a string descriptor
657 * @dev: the device whose string descriptor is being retrieved
658 * @langid: code for language chosen (from string descriptor zero)
659 * @index: the number of the descriptor
660 * @buf: where to put the string
661 * @size: how big is "buf"?
662 * Context: !in_interrupt ()
664 * Retrieves a string, encoded using UTF-16LE (Unicode, 16 bits per character,
665 * in little-endian byte order).
666 * The usb_string() function will often be a convenient way to turn
667 * these strings into kernel-printable form.
669 * Strings may be referenced in device, configuration, interface, or other
670 * descriptors, and could also be used in vendor-specific ways.
672 * This call is synchronous, and may not be used in an interrupt context.
674 * Returns the number of bytes received on success, or else the status code
675 * returned by the underlying usb_control_msg() call.
677 static int usb_get_string(struct usb_device *dev, unsigned short langid,
678 unsigned char index, void *buf, int size)
683 for (i = 0; i < 3; ++i) {
684 /* retry on length 0 or stall; some devices are flakey */
685 result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
686 USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
687 (USB_DT_STRING << 8) + index, langid, buf, size,
688 USB_CTRL_GET_TIMEOUT);
689 if (result == 0 || result == -EPIPE)
691 if (result > 1 && ((u8 *) buf)[1] != USB_DT_STRING) {
700 static void usb_try_string_workarounds(unsigned char *buf, int *length)
702 int newlength, oldlength = *length;
704 for (newlength = 2; newlength + 1 < oldlength; newlength += 2)
705 if (!isprint(buf[newlength]) || buf[newlength + 1])
714 static int usb_string_sub(struct usb_device *dev, unsigned int langid,
715 unsigned int index, unsigned char *buf)
719 /* Try to read the string descriptor by asking for the maximum
720 * possible number of bytes */
721 if (dev->quirks & USB_QUIRK_STRING_FETCH_255)
724 rc = usb_get_string(dev, langid, index, buf, 255);
726 /* If that failed try to read the descriptor length, then
727 * ask for just that many bytes */
729 rc = usb_get_string(dev, langid, index, buf, 2);
731 rc = usb_get_string(dev, langid, index, buf, buf[0]);
735 if (!buf[0] && !buf[1])
736 usb_try_string_workarounds(buf, &rc);
738 /* There might be extra junk at the end of the descriptor */
742 rc = rc - (rc & 1); /* force a multiple of two */
746 rc = (rc < 0 ? rc : -EINVAL);
751 static int usb_get_langid(struct usb_device *dev, unsigned char *tbuf)
755 if (dev->have_langid)
758 if (dev->string_langid < 0)
761 err = usb_string_sub(dev, 0, 0, tbuf);
763 /* If the string was reported but is malformed, default to english
765 if (err == -ENODATA || (err > 0 && err < 4)) {
766 dev->string_langid = 0x0409;
767 dev->have_langid = 1;
769 "string descriptor 0 malformed (err = %d), "
770 "defaulting to 0x%04x\n",
771 err, dev->string_langid);
775 /* In case of all other errors, we assume the device is not able to
776 * deal with strings at all. Set string_langid to -1 in order to
777 * prevent any string to be retrieved from the device */
779 dev_err(&dev->dev, "string descriptor 0 read error: %d\n",
781 dev->string_langid = -1;
785 /* always use the first langid listed */
786 dev->string_langid = tbuf[2] | (tbuf[3] << 8);
787 dev->have_langid = 1;
788 dev_dbg(&dev->dev, "default language 0x%04x\n",
794 * usb_string - returns UTF-8 version of a string descriptor
795 * @dev: the device whose string descriptor is being retrieved
796 * @index: the number of the descriptor
797 * @buf: where to put the string
798 * @size: how big is "buf"?
799 * Context: !in_interrupt ()
801 * This converts the UTF-16LE encoded strings returned by devices, from
802 * usb_get_string_descriptor(), to null-terminated UTF-8 encoded ones
803 * that are more usable in most kernel contexts. Note that this function
804 * chooses strings in the first language supported by the device.
806 * This call is synchronous, and may not be used in an interrupt context.
808 * Returns length of the string (>= 0) or usb_control_msg status (< 0).
810 int usb_string(struct usb_device *dev, int index, char *buf, size_t size)
815 if (dev->state == USB_STATE_SUSPENDED)
816 return -EHOSTUNREACH;
817 if (size <= 0 || !buf || !index)
820 tbuf = kmalloc(256, GFP_NOIO);
824 err = usb_get_langid(dev, tbuf);
828 err = usb_string_sub(dev, dev->string_langid, index, tbuf);
832 size--; /* leave room for trailing NULL char in output buffer */
833 err = utf16s_to_utf8s((wchar_t *) &tbuf[2], (err - 2) / 2,
834 UTF16_LITTLE_ENDIAN, buf, size);
837 if (tbuf[1] != USB_DT_STRING)
839 "wrong descriptor type %02x for string %d (\"%s\")\n",
840 tbuf[1], index, buf);
846 EXPORT_SYMBOL_GPL(usb_string);
848 /* one UTF-8-encoded 16-bit character has at most three bytes */
849 #define MAX_USB_STRING_SIZE (127 * 3 + 1)
852 * usb_cache_string - read a string descriptor and cache it for later use
853 * @udev: the device whose string descriptor is being read
854 * @index: the descriptor index
856 * Returns a pointer to a kmalloc'ed buffer containing the descriptor string,
857 * or NULL if the index is 0 or the string could not be read.
859 char *usb_cache_string(struct usb_device *udev, int index)
862 char *smallbuf = NULL;
868 buf = kmalloc(MAX_USB_STRING_SIZE, GFP_NOIO);
870 len = usb_string(udev, index, buf, MAX_USB_STRING_SIZE);
872 smallbuf = kmalloc(++len, GFP_NOIO);
875 memcpy(smallbuf, buf, len);
883 * usb_get_device_descriptor - (re)reads the device descriptor (usbcore)
884 * @dev: the device whose device descriptor is being updated
885 * @size: how much of the descriptor to read
886 * Context: !in_interrupt ()
888 * Updates the copy of the device descriptor stored in the device structure,
889 * which dedicates space for this purpose.
891 * Not exported, only for use by the core. If drivers really want to read
892 * the device descriptor directly, they can call usb_get_descriptor() with
893 * type = USB_DT_DEVICE and index = 0.
895 * This call is synchronous, and may not be used in an interrupt context.
897 * Returns the number of bytes received on success, or else the status code
898 * returned by the underlying usb_control_msg() call.
900 int usb_get_device_descriptor(struct usb_device *dev, unsigned int size)
902 struct usb_device_descriptor *desc;
905 if (size > sizeof(*desc))
907 desc = kmalloc(sizeof(*desc), GFP_NOIO);
911 ret = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, size);
913 memcpy(&dev->descriptor, desc, size);
919 * usb_get_status - issues a GET_STATUS call
920 * @dev: the device whose status is being checked
921 * @type: USB_RECIP_*; for device, interface, or endpoint
922 * @target: zero (for device), else interface or endpoint number
923 * @data: pointer to two bytes of bitmap data
924 * Context: !in_interrupt ()
926 * Returns device, interface, or endpoint status. Normally only of
927 * interest to see if the device is self powered, or has enabled the
928 * remote wakeup facility; or whether a bulk or interrupt endpoint
929 * is halted ("stalled").
931 * Bits in these status bitmaps are set using the SET_FEATURE request,
932 * and cleared using the CLEAR_FEATURE request. The usb_clear_halt()
933 * function should be used to clear halt ("stall") status.
935 * This call is synchronous, and may not be used in an interrupt context.
937 * Returns the number of bytes received on success, or else the status code
938 * returned by the underlying usb_control_msg() call.
940 int usb_get_status(struct usb_device *dev, int type, int target, void *data)
943 u16 *status = kmalloc(sizeof(*status), GFP_KERNEL);
948 ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
949 USB_REQ_GET_STATUS, USB_DIR_IN | type, 0, target, status,
950 sizeof(*status), USB_CTRL_GET_TIMEOUT);
952 *(u16 *)data = *status;
956 EXPORT_SYMBOL_GPL(usb_get_status);
959 * usb_clear_halt - tells device to clear endpoint halt/stall condition
960 * @dev: device whose endpoint is halted
961 * @pipe: endpoint "pipe" being cleared
962 * Context: !in_interrupt ()
964 * This is used to clear halt conditions for bulk and interrupt endpoints,
965 * as reported by URB completion status. Endpoints that are halted are
966 * sometimes referred to as being "stalled". Such endpoints are unable
967 * to transmit or receive data until the halt status is cleared. Any URBs
968 * queued for such an endpoint should normally be unlinked by the driver
969 * before clearing the halt condition, as described in sections 5.7.5
970 * and 5.8.5 of the USB 2.0 spec.
972 * Note that control and isochronous endpoints don't halt, although control
973 * endpoints report "protocol stall" (for unsupported requests) using the
974 * same status code used to report a true stall.
976 * This call is synchronous, and may not be used in an interrupt context.
978 * Returns zero on success, or else the status code returned by the
979 * underlying usb_control_msg() call.
981 int usb_clear_halt(struct usb_device *dev, int pipe)
984 int endp = usb_pipeendpoint(pipe);
986 if (usb_pipein(pipe))
989 /* we don't care if it wasn't halted first. in fact some devices
990 * (like some ibmcam model 1 units) seem to expect hosts to make
991 * this request for iso endpoints, which can't halt!
993 result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
994 USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
995 USB_ENDPOINT_HALT, endp, NULL, 0,
996 USB_CTRL_SET_TIMEOUT);
998 /* don't un-halt or force to DATA0 except on success */
1002 /* NOTE: seems like Microsoft and Apple don't bother verifying
1003 * the clear "took", so some devices could lock up if you check...
1004 * such as the Hagiwara FlashGate DUAL. So we won't bother.
1006 * NOTE: make sure the logic here doesn't diverge much from
1007 * the copy in usb-storage, for as long as we need two copies.
1010 usb_reset_endpoint(dev, endp);
1014 EXPORT_SYMBOL_GPL(usb_clear_halt);
1016 static int create_intf_ep_devs(struct usb_interface *intf)
1018 struct usb_device *udev = interface_to_usbdev(intf);
1019 struct usb_host_interface *alt = intf->cur_altsetting;
1022 if (intf->ep_devs_created || intf->unregistering)
1025 for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1026 (void) usb_create_ep_devs(&intf->dev, &alt->endpoint[i], udev);
1027 intf->ep_devs_created = 1;
1031 static void remove_intf_ep_devs(struct usb_interface *intf)
1033 struct usb_host_interface *alt = intf->cur_altsetting;
1036 if (!intf->ep_devs_created)
1039 for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1040 usb_remove_ep_devs(&alt->endpoint[i]);
1041 intf->ep_devs_created = 0;
1045 * usb_disable_endpoint -- Disable an endpoint by address
1046 * @dev: the device whose endpoint is being disabled
1047 * @epaddr: the endpoint's address. Endpoint number for output,
1048 * endpoint number + USB_DIR_IN for input
1049 * @reset_hardware: flag to erase any endpoint state stored in the
1050 * controller hardware
1052 * Disables the endpoint for URB submission and nukes all pending URBs.
1053 * If @reset_hardware is set then also deallocates hcd/hardware state
1056 void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr,
1057 bool reset_hardware)
1059 unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
1060 struct usb_host_endpoint *ep;
1065 if (usb_endpoint_out(epaddr)) {
1066 ep = dev->ep_out[epnum];
1068 dev->ep_out[epnum] = NULL;
1070 ep = dev->ep_in[epnum];
1072 dev->ep_in[epnum] = NULL;
1076 usb_hcd_flush_endpoint(dev, ep);
1078 usb_hcd_disable_endpoint(dev, ep);
1083 * usb_reset_endpoint - Reset an endpoint's state.
1084 * @dev: the device whose endpoint is to be reset
1085 * @epaddr: the endpoint's address. Endpoint number for output,
1086 * endpoint number + USB_DIR_IN for input
1088 * Resets any host-side endpoint state such as the toggle bit,
1089 * sequence number or current window.
1091 void usb_reset_endpoint(struct usb_device *dev, unsigned int epaddr)
1093 unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
1094 struct usb_host_endpoint *ep;
1096 if (usb_endpoint_out(epaddr))
1097 ep = dev->ep_out[epnum];
1099 ep = dev->ep_in[epnum];
1101 usb_hcd_reset_endpoint(dev, ep);
1103 EXPORT_SYMBOL_GPL(usb_reset_endpoint);
1107 * usb_disable_interface -- Disable all endpoints for an interface
1108 * @dev: the device whose interface is being disabled
1109 * @intf: pointer to the interface descriptor
1110 * @reset_hardware: flag to erase any endpoint state stored in the
1111 * controller hardware
1113 * Disables all the endpoints for the interface's current altsetting.
1115 void usb_disable_interface(struct usb_device *dev, struct usb_interface *intf,
1116 bool reset_hardware)
1118 struct usb_host_interface *alt = intf->cur_altsetting;
1121 for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
1122 usb_disable_endpoint(dev,
1123 alt->endpoint[i].desc.bEndpointAddress,
1129 * usb_disable_device - Disable all the endpoints for a USB device
1130 * @dev: the device whose endpoints are being disabled
1131 * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
1133 * Disables all the device's endpoints, potentially including endpoint 0.
1134 * Deallocates hcd/hardware state for the endpoints (nuking all or most
1135 * pending urbs) and usbcore state for the interfaces, so that usbcore
1136 * must usb_set_configuration() before any interfaces could be used.
1138 void usb_disable_device(struct usb_device *dev, int skip_ep0)
1141 struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1143 /* getting rid of interfaces will disconnect
1144 * any drivers bound to them (a key side effect)
1146 if (dev->actconfig) {
1148 * FIXME: In order to avoid self-deadlock involving the
1149 * bandwidth_mutex, we have to mark all the interfaces
1150 * before unregistering any of them.
1152 for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++)
1153 dev->actconfig->interface[i]->unregistering = 1;
1155 for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
1156 struct usb_interface *interface;
1158 /* remove this interface if it has been registered */
1159 interface = dev->actconfig->interface[i];
1160 if (!device_is_registered(&interface->dev))
1162 dev_dbg(&dev->dev, "unregistering interface %s\n",
1163 dev_name(&interface->dev));
1164 remove_intf_ep_devs(interface);
1165 device_del(&interface->dev);
1168 /* Now that the interfaces are unbound, nobody should
1169 * try to access them.
1171 for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
1172 put_device(&dev->actconfig->interface[i]->dev);
1173 dev->actconfig->interface[i] = NULL;
1175 usb_unlocked_disable_lpm(dev);
1176 usb_disable_ltm(dev);
1177 dev->actconfig = NULL;
1178 if (dev->state == USB_STATE_CONFIGURED)
1179 usb_set_device_state(dev, USB_STATE_ADDRESS);
1182 dev_dbg(&dev->dev, "%s nuking %s URBs\n", __func__,
1183 skip_ep0 ? "non-ep0" : "all");
1184 if (hcd->driver->check_bandwidth) {
1185 /* First pass: Cancel URBs, leave endpoint pointers intact. */
1186 for (i = skip_ep0; i < 16; ++i) {
1187 usb_disable_endpoint(dev, i, false);
1188 usb_disable_endpoint(dev, i + USB_DIR_IN, false);
1190 /* Remove endpoints from the host controller internal state */
1191 mutex_lock(hcd->bandwidth_mutex);
1192 usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
1193 mutex_unlock(hcd->bandwidth_mutex);
1194 /* Second pass: remove endpoint pointers */
1196 for (i = skip_ep0; i < 16; ++i) {
1197 usb_disable_endpoint(dev, i, true);
1198 usb_disable_endpoint(dev, i + USB_DIR_IN, true);
1203 * usb_enable_endpoint - Enable an endpoint for USB communications
1204 * @dev: the device whose interface is being enabled
1206 * @reset_ep: flag to reset the endpoint state
1208 * Resets the endpoint state if asked, and sets dev->ep_{in,out} pointers.
1209 * For control endpoints, both the input and output sides are handled.
1211 void usb_enable_endpoint(struct usb_device *dev, struct usb_host_endpoint *ep,
1214 int epnum = usb_endpoint_num(&ep->desc);
1215 int is_out = usb_endpoint_dir_out(&ep->desc);
1216 int is_control = usb_endpoint_xfer_control(&ep->desc);
1219 usb_hcd_reset_endpoint(dev, ep);
1220 if (is_out || is_control)
1221 dev->ep_out[epnum] = ep;
1222 if (!is_out || is_control)
1223 dev->ep_in[epnum] = ep;
1228 * usb_enable_interface - Enable all the endpoints for an interface
1229 * @dev: the device whose interface is being enabled
1230 * @intf: pointer to the interface descriptor
1231 * @reset_eps: flag to reset the endpoints' state
1233 * Enables all the endpoints for the interface's current altsetting.
1235 void usb_enable_interface(struct usb_device *dev,
1236 struct usb_interface *intf, bool reset_eps)
1238 struct usb_host_interface *alt = intf->cur_altsetting;
1241 for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1242 usb_enable_endpoint(dev, &alt->endpoint[i], reset_eps);
1246 * usb_set_interface - Makes a particular alternate setting be current
1247 * @dev: the device whose interface is being updated
1248 * @interface: the interface being updated
1249 * @alternate: the setting being chosen.
1250 * Context: !in_interrupt ()
1252 * This is used to enable data transfers on interfaces that may not
1253 * be enabled by default. Not all devices support such configurability.
1254 * Only the driver bound to an interface may change its setting.
1256 * Within any given configuration, each interface may have several
1257 * alternative settings. These are often used to control levels of
1258 * bandwidth consumption. For example, the default setting for a high
1259 * speed interrupt endpoint may not send more than 64 bytes per microframe,
1260 * while interrupt transfers of up to 3KBytes per microframe are legal.
1261 * Also, isochronous endpoints may never be part of an
1262 * interface's default setting. To access such bandwidth, alternate
1263 * interface settings must be made current.
1265 * Note that in the Linux USB subsystem, bandwidth associated with
1266 * an endpoint in a given alternate setting is not reserved until an URB
1267 * is submitted that needs that bandwidth. Some other operating systems
1268 * allocate bandwidth early, when a configuration is chosen.
1270 * This call is synchronous, and may not be used in an interrupt context.
1271 * Also, drivers must not change altsettings while urbs are scheduled for
1272 * endpoints in that interface; all such urbs must first be completed
1273 * (perhaps forced by unlinking).
1275 * Returns zero on success, or else the status code returned by the
1276 * underlying usb_control_msg() call.
1278 int usb_set_interface(struct usb_device *dev, int interface, int alternate)
1280 struct usb_interface *iface;
1281 struct usb_host_interface *alt;
1282 struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1285 unsigned int epaddr;
1288 if (dev->state == USB_STATE_SUSPENDED)
1289 return -EHOSTUNREACH;
1291 iface = usb_ifnum_to_if(dev, interface);
1293 dev_dbg(&dev->dev, "selecting invalid interface %d\n",
1297 if (iface->unregistering)
1300 alt = usb_altnum_to_altsetting(iface, alternate);
1302 dev_warn(&dev->dev, "selecting invalid altsetting %d\n",
1307 /* Make sure we have enough bandwidth for this alternate interface.
1308 * Remove the current alt setting and add the new alt setting.
1310 mutex_lock(hcd->bandwidth_mutex);
1311 /* Disable LPM, and re-enable it once the new alt setting is installed,
1312 * so that the xHCI driver can recalculate the U1/U2 timeouts.
1314 if (usb_disable_lpm(dev)) {
1315 dev_err(&iface->dev, "%s Failed to disable LPM\n.", __func__);
1316 mutex_unlock(hcd->bandwidth_mutex);
1319 ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt);
1321 dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n",
1323 usb_enable_lpm(dev);
1324 mutex_unlock(hcd->bandwidth_mutex);
1328 if (dev->quirks & USB_QUIRK_NO_SET_INTF)
1331 ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
1332 USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE,
1333 alternate, interface, NULL, 0, 5000);
1335 /* 9.4.10 says devices don't need this and are free to STALL the
1336 * request if the interface only has one alternate setting.
1338 if (ret == -EPIPE && iface->num_altsetting == 1) {
1340 "manual set_interface for iface %d, alt %d\n",
1341 interface, alternate);
1343 } else if (ret < 0) {
1344 /* Re-instate the old alt setting */
1345 usb_hcd_alloc_bandwidth(dev, NULL, alt, iface->cur_altsetting);
1346 usb_enable_lpm(dev);
1347 mutex_unlock(hcd->bandwidth_mutex);
1350 mutex_unlock(hcd->bandwidth_mutex);
1352 /* FIXME drivers shouldn't need to replicate/bugfix the logic here
1353 * when they implement async or easily-killable versions of this or
1354 * other "should-be-internal" functions (like clear_halt).
1355 * should hcd+usbcore postprocess control requests?
1358 /* prevent submissions using previous endpoint settings */
1359 if (iface->cur_altsetting != alt) {
1360 remove_intf_ep_devs(iface);
1361 usb_remove_sysfs_intf_files(iface);
1363 usb_disable_interface(dev, iface, true);
1365 iface->cur_altsetting = alt;
1367 /* Now that the interface is installed, re-enable LPM. */
1368 usb_unlocked_enable_lpm(dev);
1370 /* If the interface only has one altsetting and the device didn't
1371 * accept the request, we attempt to carry out the equivalent action
1372 * by manually clearing the HALT feature for each endpoint in the
1378 for (i = 0; i < alt->desc.bNumEndpoints; i++) {
1379 epaddr = alt->endpoint[i].desc.bEndpointAddress;
1380 pipe = __create_pipe(dev,
1381 USB_ENDPOINT_NUMBER_MASK & epaddr) |
1382 (usb_endpoint_out(epaddr) ?
1383 USB_DIR_OUT : USB_DIR_IN);
1385 usb_clear_halt(dev, pipe);
1389 /* 9.1.1.5: reset toggles for all endpoints in the new altsetting
1392 * Despite EP0 is always present in all interfaces/AS, the list of
1393 * endpoints from the descriptor does not contain EP0. Due to its
1394 * omnipresence one might expect EP0 being considered "affected" by
1395 * any SetInterface request and hence assume toggles need to be reset.
1396 * However, EP0 toggles are re-synced for every individual transfer
1397 * during the SETUP stage - hence EP0 toggles are "don't care" here.
1398 * (Likewise, EP0 never "halts" on well designed devices.)
1400 usb_enable_interface(dev, iface, true);
1401 if (device_is_registered(&iface->dev)) {
1402 usb_create_sysfs_intf_files(iface);
1403 create_intf_ep_devs(iface);
1407 EXPORT_SYMBOL_GPL(usb_set_interface);
1410 * usb_reset_configuration - lightweight device reset
1411 * @dev: the device whose configuration is being reset
1413 * This issues a standard SET_CONFIGURATION request to the device using
1414 * the current configuration. The effect is to reset most USB-related
1415 * state in the device, including interface altsettings (reset to zero),
1416 * endpoint halts (cleared), and endpoint state (only for bulk and interrupt
1417 * endpoints). Other usbcore state is unchanged, including bindings of
1418 * usb device drivers to interfaces.
1420 * Because this affects multiple interfaces, avoid using this with composite
1421 * (multi-interface) devices. Instead, the driver for each interface may
1422 * use usb_set_interface() on the interfaces it claims. Be careful though;
1423 * some devices don't support the SET_INTERFACE request, and others won't
1424 * reset all the interface state (notably endpoint state). Resetting the whole
1425 * configuration would affect other drivers' interfaces.
1427 * The caller must own the device lock.
1429 * Returns zero on success, else a negative error code.
1431 int usb_reset_configuration(struct usb_device *dev)
1434 struct usb_host_config *config;
1435 struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1437 if (dev->state == USB_STATE_SUSPENDED)
1438 return -EHOSTUNREACH;
1440 /* caller must have locked the device and must own
1441 * the usb bus readlock (so driver bindings are stable);
1442 * calls during probe() are fine
1445 for (i = 1; i < 16; ++i) {
1446 usb_disable_endpoint(dev, i, true);
1447 usb_disable_endpoint(dev, i + USB_DIR_IN, true);
1450 config = dev->actconfig;
1452 mutex_lock(hcd->bandwidth_mutex);
1453 /* Disable LPM, and re-enable it once the configuration is reset, so
1454 * that the xHCI driver can recalculate the U1/U2 timeouts.
1456 if (usb_disable_lpm(dev)) {
1457 dev_err(&dev->dev, "%s Failed to disable LPM\n.", __func__);
1458 mutex_unlock(hcd->bandwidth_mutex);
1461 /* Make sure we have enough bandwidth for each alternate setting 0 */
1462 for (i = 0; i < config->desc.bNumInterfaces; i++) {
1463 struct usb_interface *intf = config->interface[i];
1464 struct usb_host_interface *alt;
1466 alt = usb_altnum_to_altsetting(intf, 0);
1468 alt = &intf->altsetting[0];
1469 if (alt != intf->cur_altsetting)
1470 retval = usb_hcd_alloc_bandwidth(dev, NULL,
1471 intf->cur_altsetting, alt);
1475 /* If not, reinstate the old alternate settings */
1478 for (i--; i >= 0; i--) {
1479 struct usb_interface *intf = config->interface[i];
1480 struct usb_host_interface *alt;
1482 alt = usb_altnum_to_altsetting(intf, 0);
1484 alt = &intf->altsetting[0];
1485 if (alt != intf->cur_altsetting)
1486 usb_hcd_alloc_bandwidth(dev, NULL,
1487 alt, intf->cur_altsetting);
1489 usb_enable_lpm(dev);
1490 mutex_unlock(hcd->bandwidth_mutex);
1493 retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
1494 USB_REQ_SET_CONFIGURATION, 0,
1495 config->desc.bConfigurationValue, 0,
1496 NULL, 0, USB_CTRL_SET_TIMEOUT);
1498 goto reset_old_alts;
1499 mutex_unlock(hcd->bandwidth_mutex);
1501 /* re-init hc/hcd interface/endpoint state */
1502 for (i = 0; i < config->desc.bNumInterfaces; i++) {
1503 struct usb_interface *intf = config->interface[i];
1504 struct usb_host_interface *alt;
1506 alt = usb_altnum_to_altsetting(intf, 0);
1508 /* No altsetting 0? We'll assume the first altsetting.
1509 * We could use a GetInterface call, but if a device is
1510 * so non-compliant that it doesn't have altsetting 0
1511 * then I wouldn't trust its reply anyway.
1514 alt = &intf->altsetting[0];
1516 if (alt != intf->cur_altsetting) {
1517 remove_intf_ep_devs(intf);
1518 usb_remove_sysfs_intf_files(intf);
1520 intf->cur_altsetting = alt;
1521 usb_enable_interface(dev, intf, true);
1522 if (device_is_registered(&intf->dev)) {
1523 usb_create_sysfs_intf_files(intf);
1524 create_intf_ep_devs(intf);
1527 /* Now that the interfaces are installed, re-enable LPM. */
1528 usb_unlocked_enable_lpm(dev);
1531 EXPORT_SYMBOL_GPL(usb_reset_configuration);
1533 static void usb_release_interface(struct device *dev)
1535 struct usb_interface *intf = to_usb_interface(dev);
1536 struct usb_interface_cache *intfc =
1537 altsetting_to_usb_interface_cache(intf->altsetting);
1539 kref_put(&intfc->ref, usb_release_interface_cache);
1543 static int usb_if_uevent(struct device *dev, struct kobj_uevent_env *env)
1545 struct usb_device *usb_dev;
1546 struct usb_interface *intf;
1547 struct usb_host_interface *alt;
1549 intf = to_usb_interface(dev);
1550 usb_dev = interface_to_usbdev(intf);
1551 alt = intf->cur_altsetting;
1553 if (add_uevent_var(env, "INTERFACE=%d/%d/%d",
1554 alt->desc.bInterfaceClass,
1555 alt->desc.bInterfaceSubClass,
1556 alt->desc.bInterfaceProtocol))
1559 if (add_uevent_var(env,
1561 "v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02Xin%02X",
1562 le16_to_cpu(usb_dev->descriptor.idVendor),
1563 le16_to_cpu(usb_dev->descriptor.idProduct),
1564 le16_to_cpu(usb_dev->descriptor.bcdDevice),
1565 usb_dev->descriptor.bDeviceClass,
1566 usb_dev->descriptor.bDeviceSubClass,
1567 usb_dev->descriptor.bDeviceProtocol,
1568 alt->desc.bInterfaceClass,
1569 alt->desc.bInterfaceSubClass,
1570 alt->desc.bInterfaceProtocol,
1571 alt->desc.bInterfaceNumber))
1577 struct device_type usb_if_device_type = {
1578 .name = "usb_interface",
1579 .release = usb_release_interface,
1580 .uevent = usb_if_uevent,
1583 static struct usb_interface_assoc_descriptor *find_iad(struct usb_device *dev,
1584 struct usb_host_config *config,
1587 struct usb_interface_assoc_descriptor *retval = NULL;
1588 struct usb_interface_assoc_descriptor *intf_assoc;
1593 for (i = 0; (i < USB_MAXIADS && config->intf_assoc[i]); i++) {
1594 intf_assoc = config->intf_assoc[i];
1595 if (intf_assoc->bInterfaceCount == 0)
1598 first_intf = intf_assoc->bFirstInterface;
1599 last_intf = first_intf + (intf_assoc->bInterfaceCount - 1);
1600 if (inum >= first_intf && inum <= last_intf) {
1602 retval = intf_assoc;
1604 dev_err(&dev->dev, "Interface #%d referenced"
1605 " by multiple IADs\n", inum);
1614 * Internal function to queue a device reset
1616 * This is initialized into the workstruct in 'struct
1617 * usb_device->reset_ws' that is launched by
1618 * message.c:usb_set_configuration() when initializing each 'struct
1621 * It is safe to get the USB device without reference counts because
1622 * the life cycle of @iface is bound to the life cycle of @udev. Then,
1623 * this function will be ran only if @iface is alive (and before
1624 * freeing it any scheduled instances of it will have been cancelled).
1626 * We need to set a flag (usb_dev->reset_running) because when we call
1627 * the reset, the interfaces might be unbound. The current interface
1628 * cannot try to remove the queued work as it would cause a deadlock
1629 * (you cannot remove your work from within your executing
1630 * workqueue). This flag lets it know, so that
1631 * usb_cancel_queued_reset() doesn't try to do it.
1633 * See usb_queue_reset_device() for more details
1635 static void __usb_queue_reset_device(struct work_struct *ws)
1638 struct usb_interface *iface =
1639 container_of(ws, struct usb_interface, reset_ws);
1640 struct usb_device *udev = interface_to_usbdev(iface);
1642 rc = usb_lock_device_for_reset(udev, iface);
1644 iface->reset_running = 1;
1645 usb_reset_device(udev);
1646 iface->reset_running = 0;
1647 usb_unlock_device(udev);
1653 * usb_set_configuration - Makes a particular device setting be current
1654 * @dev: the device whose configuration is being updated
1655 * @configuration: the configuration being chosen.
1656 * Context: !in_interrupt(), caller owns the device lock
1658 * This is used to enable non-default device modes. Not all devices
1659 * use this kind of configurability; many devices only have one
1662 * @configuration is the value of the configuration to be installed.
1663 * According to the USB spec (e.g. section 9.1.1.5), configuration values
1664 * must be non-zero; a value of zero indicates that the device in
1665 * unconfigured. However some devices erroneously use 0 as one of their
1666 * configuration values. To help manage such devices, this routine will
1667 * accept @configuration = -1 as indicating the device should be put in
1668 * an unconfigured state.
1670 * USB device configurations may affect Linux interoperability,
1671 * power consumption and the functionality available. For example,
1672 * the default configuration is limited to using 100mA of bus power,
1673 * so that when certain device functionality requires more power,
1674 * and the device is bus powered, that functionality should be in some
1675 * non-default device configuration. Other device modes may also be
1676 * reflected as configuration options, such as whether two ISDN
1677 * channels are available independently; and choosing between open
1678 * standard device protocols (like CDC) or proprietary ones.
1680 * Note that a non-authorized device (dev->authorized == 0) will only
1681 * be put in unconfigured mode.
1683 * Note that USB has an additional level of device configurability,
1684 * associated with interfaces. That configurability is accessed using
1685 * usb_set_interface().
1687 * This call is synchronous. The calling context must be able to sleep,
1688 * must own the device lock, and must not hold the driver model's USB
1689 * bus mutex; usb interface driver probe() methods cannot use this routine.
1691 * Returns zero on success, or else the status code returned by the
1692 * underlying call that failed. On successful completion, each interface
1693 * in the original device configuration has been destroyed, and each one
1694 * in the new configuration has been probed by all relevant usb device
1695 * drivers currently known to the kernel.
1697 int usb_set_configuration(struct usb_device *dev, int configuration)
1700 struct usb_host_config *cp = NULL;
1701 struct usb_interface **new_interfaces = NULL;
1702 struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1705 if (dev->authorized == 0 || configuration == -1)
1708 for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
1709 if (dev->config[i].desc.bConfigurationValue ==
1711 cp = &dev->config[i];
1716 if ((!cp && configuration != 0))
1719 /* The USB spec says configuration 0 means unconfigured.
1720 * But if a device includes a configuration numbered 0,
1721 * we will accept it as a correctly configured state.
1722 * Use -1 if you really want to unconfigure the device.
1724 if (cp && configuration == 0)
1725 dev_warn(&dev->dev, "config 0 descriptor??\n");
1727 /* Allocate memory for new interfaces before doing anything else,
1728 * so that if we run out then nothing will have changed. */
1731 nintf = cp->desc.bNumInterfaces;
1732 new_interfaces = kmalloc(nintf * sizeof(*new_interfaces),
1734 if (!new_interfaces) {
1735 dev_err(&dev->dev, "Out of memory\n");
1739 for (; n < nintf; ++n) {
1740 new_interfaces[n] = kzalloc(
1741 sizeof(struct usb_interface),
1743 if (!new_interfaces[n]) {
1744 dev_err(&dev->dev, "Out of memory\n");
1748 kfree(new_interfaces[n]);
1749 kfree(new_interfaces);
1754 i = dev->bus_mA - usb_get_max_power(dev, cp);
1756 dev_warn(&dev->dev, "new config #%d exceeds power "
1761 /* Wake up the device so we can send it the Set-Config request */
1762 ret = usb_autoresume_device(dev);
1764 goto free_interfaces;
1766 /* if it's already configured, clear out old state first.
1767 * getting rid of old interfaces means unbinding their drivers.
1769 if (dev->state != USB_STATE_ADDRESS)
1770 usb_disable_device(dev, 1); /* Skip ep0 */
1772 /* Get rid of pending async Set-Config requests for this device */
1773 cancel_async_set_config(dev);
1775 /* Make sure we have bandwidth (and available HCD resources) for this
1776 * configuration. Remove endpoints from the schedule if we're dropping
1777 * this configuration to set configuration 0. After this point, the
1778 * host controller will not allow submissions to dropped endpoints. If
1779 * this call fails, the device state is unchanged.
1781 mutex_lock(hcd->bandwidth_mutex);
1782 /* Disable LPM, and re-enable it once the new configuration is
1783 * installed, so that the xHCI driver can recalculate the U1/U2
1786 if (dev->actconfig && usb_disable_lpm(dev)) {
1787 dev_err(&dev->dev, "%s Failed to disable LPM\n.", __func__);
1788 mutex_unlock(hcd->bandwidth_mutex);
1790 goto free_interfaces;
1792 ret = usb_hcd_alloc_bandwidth(dev, cp, NULL, NULL);
1795 usb_enable_lpm(dev);
1796 mutex_unlock(hcd->bandwidth_mutex);
1797 usb_autosuspend_device(dev);
1798 goto free_interfaces;
1802 * Initialize the new interface structures and the
1803 * hc/hcd/usbcore interface/endpoint state.
1805 for (i = 0; i < nintf; ++i) {
1806 struct usb_interface_cache *intfc;
1807 struct usb_interface *intf;
1808 struct usb_host_interface *alt;
1810 cp->interface[i] = intf = new_interfaces[i];
1811 intfc = cp->intf_cache[i];
1812 intf->altsetting = intfc->altsetting;
1813 intf->num_altsetting = intfc->num_altsetting;
1814 kref_get(&intfc->ref);
1816 alt = usb_altnum_to_altsetting(intf, 0);
1818 /* No altsetting 0? We'll assume the first altsetting.
1819 * We could use a GetInterface call, but if a device is
1820 * so non-compliant that it doesn't have altsetting 0
1821 * then I wouldn't trust its reply anyway.
1824 alt = &intf->altsetting[0];
1827 find_iad(dev, cp, alt->desc.bInterfaceNumber);
1828 intf->cur_altsetting = alt;
1829 usb_enable_interface(dev, intf, true);
1830 intf->dev.parent = &dev->dev;
1831 intf->dev.driver = NULL;
1832 intf->dev.bus = &usb_bus_type;
1833 intf->dev.type = &usb_if_device_type;
1834 intf->dev.groups = usb_interface_groups;
1835 intf->dev.dma_mask = dev->dev.dma_mask;
1836 INIT_WORK(&intf->reset_ws, __usb_queue_reset_device);
1838 device_initialize(&intf->dev);
1839 pm_runtime_no_callbacks(&intf->dev);
1840 dev_set_name(&intf->dev, "%d-%s:%d.%d",
1841 dev->bus->busnum, dev->devpath,
1842 configuration, alt->desc.bInterfaceNumber);
1844 kfree(new_interfaces);
1846 ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
1847 USB_REQ_SET_CONFIGURATION, 0, configuration, 0,
1848 NULL, 0, USB_CTRL_SET_TIMEOUT);
1849 if (ret < 0 && cp) {
1851 * All the old state is gone, so what else can we do?
1852 * The device is probably useless now anyway.
1854 usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
1855 for (i = 0; i < nintf; ++i) {
1856 usb_disable_interface(dev, cp->interface[i], true);
1857 put_device(&cp->interface[i]->dev);
1858 cp->interface[i] = NULL;
1863 dev->actconfig = cp;
1864 mutex_unlock(hcd->bandwidth_mutex);
1867 usb_set_device_state(dev, USB_STATE_ADDRESS);
1869 /* Leave LPM disabled while the device is unconfigured. */
1870 usb_autosuspend_device(dev);
1873 usb_set_device_state(dev, USB_STATE_CONFIGURED);
1875 if (cp->string == NULL &&
1876 !(dev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS))
1877 cp->string = usb_cache_string(dev, cp->desc.iConfiguration);
1879 /* Now that the interfaces are installed, re-enable LPM. */
1880 usb_unlocked_enable_lpm(dev);
1881 /* Enable LTM if it was turned off by usb_disable_device. */
1882 usb_enable_ltm(dev);
1884 /* Now that all the interfaces are set up, register them
1885 * to trigger binding of drivers to interfaces. probe()
1886 * routines may install different altsettings and may
1887 * claim() any interfaces not yet bound. Many class drivers
1888 * need that: CDC, audio, video, etc.
1890 for (i = 0; i < nintf; ++i) {
1891 struct usb_interface *intf = cp->interface[i];
1894 "adding %s (config #%d, interface %d)\n",
1895 dev_name(&intf->dev), configuration,
1896 intf->cur_altsetting->desc.bInterfaceNumber);
1897 device_enable_async_suspend(&intf->dev);
1898 ret = device_add(&intf->dev);
1900 dev_err(&dev->dev, "device_add(%s) --> %d\n",
1901 dev_name(&intf->dev), ret);
1904 create_intf_ep_devs(intf);
1907 usb_autosuspend_device(dev);
1911 static LIST_HEAD(set_config_list);
1912 static DEFINE_SPINLOCK(set_config_lock);
1914 struct set_config_request {
1915 struct usb_device *udev;
1917 struct work_struct work;
1918 struct list_head node;
1921 /* Worker routine for usb_driver_set_configuration() */
1922 static void driver_set_config_work(struct work_struct *work)
1924 struct set_config_request *req =
1925 container_of(work, struct set_config_request, work);
1926 struct usb_device *udev = req->udev;
1928 usb_lock_device(udev);
1929 spin_lock(&set_config_lock);
1930 list_del(&req->node);
1931 spin_unlock(&set_config_lock);
1933 if (req->config >= -1) /* Is req still valid? */
1934 usb_set_configuration(udev, req->config);
1935 usb_unlock_device(udev);
1940 /* Cancel pending Set-Config requests for a device whose configuration
1943 static void cancel_async_set_config(struct usb_device *udev)
1945 struct set_config_request *req;
1947 spin_lock(&set_config_lock);
1948 list_for_each_entry(req, &set_config_list, node) {
1949 if (req->udev == udev)
1950 req->config = -999; /* Mark as cancelled */
1952 spin_unlock(&set_config_lock);
1956 * usb_driver_set_configuration - Provide a way for drivers to change device configurations
1957 * @udev: the device whose configuration is being updated
1958 * @config: the configuration being chosen.
1959 * Context: In process context, must be able to sleep
1961 * Device interface drivers are not allowed to change device configurations.
1962 * This is because changing configurations will destroy the interface the
1963 * driver is bound to and create new ones; it would be like a floppy-disk
1964 * driver telling the computer to replace the floppy-disk drive with a
1967 * Still, in certain specialized circumstances the need may arise. This
1968 * routine gets around the normal restrictions by using a work thread to
1969 * submit the change-config request.
1971 * Returns 0 if the request was successfully queued, error code otherwise.
1972 * The caller has no way to know whether the queued request will eventually
1975 int usb_driver_set_configuration(struct usb_device *udev, int config)
1977 struct set_config_request *req;
1979 req = kmalloc(sizeof(*req), GFP_KERNEL);
1983 req->config = config;
1984 INIT_WORK(&req->work, driver_set_config_work);
1986 spin_lock(&set_config_lock);
1987 list_add(&req->node, &set_config_list);
1988 spin_unlock(&set_config_lock);
1991 schedule_work(&req->work);
1994 EXPORT_SYMBOL_GPL(usb_driver_set_configuration);