2 * message.c - synchronous message handling
4 * Released under the GPLv2 only.
5 * SPDX-License-Identifier: GPL-2.0
8 #include <linux/pci.h> /* for scatterlist macros */
10 #include <linux/module.h>
11 #include <linux/slab.h>
13 #include <linux/timer.h>
14 #include <linux/ctype.h>
15 #include <linux/nls.h>
16 #include <linux/device.h>
17 #include <linux/scatterlist.h>
18 #include <linux/usb/cdc.h>
19 #include <linux/usb/quirks.h>
20 #include <linux/usb/hcd.h> /* for usbcore internals */
21 #include <asm/byteorder.h>
25 static void cancel_async_set_config(struct usb_device *udev);
28 struct completion done;
32 static void usb_api_blocking_completion(struct urb *urb)
34 struct api_context *ctx = urb->context;
36 ctx->status = urb->status;
42 * Starts urb and waits for completion or timeout. Note that this call
43 * is NOT interruptible. Many device driver i/o requests should be
44 * interruptible and therefore these drivers should implement their
45 * own interruptible routines.
47 static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)
49 struct api_context ctx;
53 init_completion(&ctx.done);
55 urb->actual_length = 0;
56 retval = usb_submit_urb(urb, GFP_NOIO);
60 expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT;
61 if (!wait_for_completion_timeout(&ctx.done, expire)) {
63 retval = (ctx.status == -ENOENT ? -ETIMEDOUT : ctx.status);
65 dev_dbg(&urb->dev->dev,
66 "%s timed out on ep%d%s len=%u/%u\n",
68 usb_endpoint_num(&urb->ep->desc),
69 usb_urb_dir_in(urb) ? "in" : "out",
71 urb->transfer_buffer_length);
76 *actual_length = urb->actual_length;
82 /*-------------------------------------------------------------------*/
83 /* returns status (negative) or length (positive) */
84 static int usb_internal_control_msg(struct usb_device *usb_dev,
86 struct usb_ctrlrequest *cmd,
87 void *data, int len, int timeout)
93 urb = usb_alloc_urb(0, GFP_NOIO);
97 usb_fill_control_urb(urb, usb_dev, pipe, (unsigned char *)cmd, data,
98 len, usb_api_blocking_completion, NULL);
100 retv = usb_start_wait_urb(urb, timeout, &length);
108 * usb_control_msg - Builds a control urb, sends it off and waits for completion
109 * @dev: pointer to the usb device to send the message to
110 * @pipe: endpoint "pipe" to send the message to
111 * @request: USB message request value
112 * @requesttype: USB message request type value
113 * @value: USB message value
114 * @index: USB message index value
115 * @data: pointer to the data to send
116 * @size: length in bytes of the data to send
117 * @timeout: time in msecs to wait for the message to complete before timing
118 * out (if 0 the wait is forever)
120 * Context: !in_interrupt ()
122 * This function sends a simple control message to a specified endpoint and
123 * waits for the message to complete, or timeout.
125 * Don't use this function from within an interrupt context. If you need
126 * an asynchronous message, or need to send a message from within interrupt
127 * context, use usb_submit_urb(). If a thread in your driver uses this call,
128 * make sure your disconnect() method can wait for it to complete. Since you
129 * don't have a handle on the URB used, you can't cancel the request.
131 * Return: If successful, the number of bytes transferred. Otherwise, a negative
134 int usb_control_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
135 __u8 requesttype, __u16 value, __u16 index, void *data,
136 __u16 size, int timeout)
138 struct usb_ctrlrequest *dr;
141 dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_NOIO);
145 dr->bRequestType = requesttype;
146 dr->bRequest = request;
147 dr->wValue = cpu_to_le16(value);
148 dr->wIndex = cpu_to_le16(index);
149 dr->wLength = cpu_to_le16(size);
151 ret = usb_internal_control_msg(dev, pipe, dr, data, size, timeout);
153 /* Linger a bit, prior to the next control message. */
154 if (dev->quirks & USB_QUIRK_DELAY_CTRL_MSG)
161 EXPORT_SYMBOL_GPL(usb_control_msg);
164 * usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for completion
165 * @usb_dev: pointer to the usb device to send the message to
166 * @pipe: endpoint "pipe" to send the message to
167 * @data: pointer to the data to send
168 * @len: length in bytes of the data to send
169 * @actual_length: pointer to a location to put the actual length transferred
171 * @timeout: time in msecs to wait for the message to complete before
172 * timing out (if 0 the wait is forever)
174 * Context: !in_interrupt ()
176 * This function sends a simple interrupt message to a specified endpoint and
177 * waits for the message to complete, or timeout.
179 * Don't use this function from within an interrupt context. If you need
180 * an asynchronous message, or need to send a message from within interrupt
181 * context, use usb_submit_urb() If a thread in your driver uses this call,
182 * make sure your disconnect() method can wait for it to complete. Since you
183 * don't have a handle on the URB used, you can't cancel the request.
186 * If successful, 0. Otherwise a negative error number. The number of actual
187 * bytes transferred will be stored in the @actual_length parameter.
189 int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe,
190 void *data, int len, int *actual_length, int timeout)
192 return usb_bulk_msg(usb_dev, pipe, data, len, actual_length, timeout);
194 EXPORT_SYMBOL_GPL(usb_interrupt_msg);
197 * usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion
198 * @usb_dev: pointer to the usb device to send the message to
199 * @pipe: endpoint "pipe" to send the message to
200 * @data: pointer to the data to send
201 * @len: length in bytes of the data to send
202 * @actual_length: pointer to a location to put the actual length transferred
204 * @timeout: time in msecs to wait for the message to complete before
205 * timing out (if 0 the wait is forever)
207 * Context: !in_interrupt ()
209 * This function sends a simple bulk message to a specified endpoint
210 * and waits for the message to complete, or timeout.
212 * Don't use this function from within an interrupt context. If you need
213 * an asynchronous message, or need to send a message from within interrupt
214 * context, use usb_submit_urb() If a thread in your driver uses this call,
215 * make sure your disconnect() method can wait for it to complete. Since you
216 * don't have a handle on the URB used, you can't cancel the request.
218 * Because there is no usb_interrupt_msg() and no USBDEVFS_INTERRUPT ioctl,
219 * users are forced to abuse this routine by using it to submit URBs for
220 * interrupt endpoints. We will take the liberty of creating an interrupt URB
221 * (with the default interval) if the target is an interrupt endpoint.
224 * If successful, 0. Otherwise a negative error number. The number of actual
225 * bytes transferred will be stored in the @actual_length parameter.
228 int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe,
229 void *data, int len, int *actual_length, int timeout)
232 struct usb_host_endpoint *ep;
234 ep = usb_pipe_endpoint(usb_dev, pipe);
238 urb = usb_alloc_urb(0, GFP_KERNEL);
242 if ((ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
243 USB_ENDPOINT_XFER_INT) {
244 pipe = (pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30);
245 usb_fill_int_urb(urb, usb_dev, pipe, data, len,
246 usb_api_blocking_completion, NULL,
249 usb_fill_bulk_urb(urb, usb_dev, pipe, data, len,
250 usb_api_blocking_completion, NULL);
252 return usb_start_wait_urb(urb, timeout, actual_length);
254 EXPORT_SYMBOL_GPL(usb_bulk_msg);
256 /*-------------------------------------------------------------------*/
258 static void sg_clean(struct usb_sg_request *io)
261 while (io->entries--)
262 usb_free_urb(io->urbs[io->entries]);
269 static void sg_complete(struct urb *urb)
271 struct usb_sg_request *io = urb->context;
272 int status = urb->status;
274 spin_lock(&io->lock);
276 /* In 2.5 we require hcds' endpoint queues not to progress after fault
277 * reports, until the completion callback (this!) returns. That lets
278 * device driver code (like this routine) unlink queued urbs first,
279 * if it needs to, since the HC won't work on them at all. So it's
280 * not possible for page N+1 to overwrite page N, and so on.
282 * That's only for "hard" faults; "soft" faults (unlinks) sometimes
283 * complete before the HCD can get requests away from hardware,
284 * though never during cleanup after a hard fault.
287 && (io->status != -ECONNRESET
288 || status != -ECONNRESET)
289 && urb->actual_length) {
290 dev_err(io->dev->bus->controller,
291 "dev %s ep%d%s scatterlist error %d/%d\n",
293 usb_endpoint_num(&urb->ep->desc),
294 usb_urb_dir_in(urb) ? "in" : "out",
299 if (io->status == 0 && status && status != -ECONNRESET) {
300 int i, found, retval;
304 /* the previous urbs, and this one, completed already.
305 * unlink pending urbs so they won't rx/tx bad data.
306 * careful: unlink can sometimes be synchronous...
308 spin_unlock(&io->lock);
309 for (i = 0, found = 0; i < io->entries; i++) {
313 usb_block_urb(io->urbs[i]);
314 retval = usb_unlink_urb(io->urbs[i]);
315 if (retval != -EINPROGRESS &&
319 dev_err(&io->dev->dev,
320 "%s, unlink --> %d\n",
322 } else if (urb == io->urbs[i])
325 spin_lock(&io->lock);
328 /* on the last completion, signal usb_sg_wait() */
329 io->bytes += urb->actual_length;
332 complete(&io->complete);
334 spin_unlock(&io->lock);
339 * usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request
340 * @io: request block being initialized. until usb_sg_wait() returns,
341 * treat this as a pointer to an opaque block of memory,
342 * @dev: the usb device that will send or receive the data
343 * @pipe: endpoint "pipe" used to transfer the data
344 * @period: polling rate for interrupt endpoints, in frames or
345 * (for high speed endpoints) microframes; ignored for bulk
346 * @sg: scatterlist entries
347 * @nents: how many entries in the scatterlist
348 * @length: how many bytes to send from the scatterlist, or zero to
349 * send every byte identified in the list.
350 * @mem_flags: SLAB_* flags affecting memory allocations in this call
352 * This initializes a scatter/gather request, allocating resources such as
353 * I/O mappings and urb memory (except maybe memory used by USB controller
356 * The request must be issued using usb_sg_wait(), which waits for the I/O to
357 * complete (or to be canceled) and then cleans up all resources allocated by
360 * The request may be canceled with usb_sg_cancel(), either before or after
361 * usb_sg_wait() is called.
363 * Return: Zero for success, else a negative errno value.
365 int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
366 unsigned pipe, unsigned period, struct scatterlist *sg,
367 int nents, size_t length, gfp_t mem_flags)
373 if (!io || !dev || !sg
374 || usb_pipecontrol(pipe)
375 || usb_pipeisoc(pipe)
379 spin_lock_init(&io->lock);
383 if (dev->bus->sg_tablesize > 0) {
391 /* initialize all the urbs we'll use */
392 io->urbs = kmalloc(io->entries * sizeof(*io->urbs), mem_flags);
396 urb_flags = URB_NO_INTERRUPT;
397 if (usb_pipein(pipe))
398 urb_flags |= URB_SHORT_NOT_OK;
400 for_each_sg(sg, sg, io->entries, i) {
404 urb = usb_alloc_urb(0, mem_flags);
413 urb->interval = period;
414 urb->transfer_flags = urb_flags;
415 urb->complete = sg_complete;
420 /* There is no single transfer buffer */
421 urb->transfer_buffer = NULL;
422 urb->num_sgs = nents;
424 /* A length of zero means transfer the whole sg list */
427 struct scatterlist *sg2;
430 for_each_sg(sg, sg2, nents, j)
435 * Some systems can't use DMA; they use PIO instead.
436 * For their sakes, transfer_buffer is set whenever
439 if (!PageHighMem(sg_page(sg)))
440 urb->transfer_buffer = sg_virt(sg);
442 urb->transfer_buffer = NULL;
446 len = min_t(size_t, len, length);
452 urb->transfer_buffer_length = len;
454 io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT;
456 /* transaction state */
457 io->count = io->entries;
460 init_completion(&io->complete);
467 EXPORT_SYMBOL_GPL(usb_sg_init);
470 * usb_sg_wait - synchronously execute scatter/gather request
471 * @io: request block handle, as initialized with usb_sg_init().
472 * some fields become accessible when this call returns.
473 * Context: !in_interrupt ()
475 * This function blocks until the specified I/O operation completes. It
476 * leverages the grouping of the related I/O requests to get good transfer
477 * rates, by queueing the requests. At higher speeds, such queuing can
478 * significantly improve USB throughput.
480 * There are three kinds of completion for this function.
482 * (1) success, where io->status is zero. The number of io->bytes
483 * transferred is as requested.
484 * (2) error, where io->status is a negative errno value. The number
485 * of io->bytes transferred before the error is usually less
486 * than requested, and can be nonzero.
487 * (3) cancellation, a type of error with status -ECONNRESET that
488 * is initiated by usb_sg_cancel().
490 * When this function returns, all memory allocated through usb_sg_init() or
491 * this call will have been freed. The request block parameter may still be
492 * passed to usb_sg_cancel(), or it may be freed. It could also be
493 * reinitialized and then reused.
495 * Data Transfer Rates:
497 * Bulk transfers are valid for full or high speed endpoints.
498 * The best full speed data rate is 19 packets of 64 bytes each
499 * per frame, or 1216 bytes per millisecond.
500 * The best high speed data rate is 13 packets of 512 bytes each
501 * per microframe, or 52 KBytes per millisecond.
503 * The reason to use interrupt transfers through this API would most likely
504 * be to reserve high speed bandwidth, where up to 24 KBytes per millisecond
505 * could be transferred. That capability is less useful for low or full
506 * speed interrupt endpoints, which allow at most one packet per millisecond,
507 * of at most 8 or 64 bytes (respectively).
509 * It is not necessary to call this function to reserve bandwidth for devices
510 * under an xHCI host controller, as the bandwidth is reserved when the
511 * configuration or interface alt setting is selected.
513 void usb_sg_wait(struct usb_sg_request *io)
516 int entries = io->entries;
518 /* queue the urbs. */
519 spin_lock_irq(&io->lock);
521 while (i < entries && !io->status) {
524 io->urbs[i]->dev = io->dev;
525 spin_unlock_irq(&io->lock);
527 retval = usb_submit_urb(io->urbs[i], GFP_NOIO);
530 /* maybe we retrying will recover */
531 case -ENXIO: /* hc didn't queue this one */
538 /* no error? continue immediately.
540 * NOTE: to work better with UHCI (4K I/O buffer may
541 * need 3K of TDs) it may be good to limit how many
542 * URBs are queued at once; N milliseconds?
549 /* fail any uncompleted urbs */
551 io->urbs[i]->status = retval;
552 dev_dbg(&io->dev->dev, "%s, submit --> %d\n",
556 spin_lock_irq(&io->lock);
557 if (retval && (io->status == 0 || io->status == -ECONNRESET))
560 io->count -= entries - i;
562 complete(&io->complete);
563 spin_unlock_irq(&io->lock);
565 /* OK, yes, this could be packaged as non-blocking.
566 * So could the submit loop above ... but it's easier to
567 * solve neither problem than to solve both!
569 wait_for_completion(&io->complete);
573 EXPORT_SYMBOL_GPL(usb_sg_wait);
576 * usb_sg_cancel - stop scatter/gather i/o issued by usb_sg_wait()
577 * @io: request block, initialized with usb_sg_init()
579 * This stops a request after it has been started by usb_sg_wait().
580 * It can also prevents one initialized by usb_sg_init() from starting,
581 * so that call just frees resources allocated to the request.
583 void usb_sg_cancel(struct usb_sg_request *io)
588 spin_lock_irqsave(&io->lock, flags);
589 if (io->status || io->count == 0) {
590 spin_unlock_irqrestore(&io->lock, flags);
593 /* shut everything down */
594 io->status = -ECONNRESET;
595 io->count++; /* Keep the request alive until we're done */
596 spin_unlock_irqrestore(&io->lock, flags);
598 for (i = io->entries - 1; i >= 0; --i) {
599 usb_block_urb(io->urbs[i]);
601 retval = usb_unlink_urb(io->urbs[i]);
602 if (retval != -EINPROGRESS
606 dev_warn(&io->dev->dev, "%s, unlink --> %d\n",
610 spin_lock_irqsave(&io->lock, flags);
613 complete(&io->complete);
614 spin_unlock_irqrestore(&io->lock, flags);
616 EXPORT_SYMBOL_GPL(usb_sg_cancel);
618 /*-------------------------------------------------------------------*/
621 * usb_get_descriptor - issues a generic GET_DESCRIPTOR request
622 * @dev: the device whose descriptor is being retrieved
623 * @type: the descriptor type (USB_DT_*)
624 * @index: the number of the descriptor
625 * @buf: where to put the descriptor
626 * @size: how big is "buf"?
627 * Context: !in_interrupt ()
629 * Gets a USB descriptor. Convenience functions exist to simplify
630 * getting some types of descriptors. Use
631 * usb_get_string() or usb_string() for USB_DT_STRING.
632 * Device (USB_DT_DEVICE) and configuration descriptors (USB_DT_CONFIG)
633 * are part of the device structure.
634 * In addition to a number of USB-standard descriptors, some
635 * devices also use class-specific or vendor-specific descriptors.
637 * This call is synchronous, and may not be used in an interrupt context.
639 * Return: The number of bytes received on success, or else the status code
640 * returned by the underlying usb_control_msg() call.
642 int usb_get_descriptor(struct usb_device *dev, unsigned char type,
643 unsigned char index, void *buf, int size)
648 memset(buf, 0, size); /* Make sure we parse really received data */
650 for (i = 0; i < 3; ++i) {
651 /* retry on length 0 or error; some devices are flakey */
652 result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
653 USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
654 (type << 8) + index, 0, buf, size,
655 USB_CTRL_GET_TIMEOUT);
656 if (result <= 0 && result != -ETIMEDOUT)
658 if (result > 1 && ((u8 *)buf)[1] != type) {
666 EXPORT_SYMBOL_GPL(usb_get_descriptor);
669 * usb_get_string - gets a string descriptor
670 * @dev: the device whose string descriptor is being retrieved
671 * @langid: code for language chosen (from string descriptor zero)
672 * @index: the number of the descriptor
673 * @buf: where to put the string
674 * @size: how big is "buf"?
675 * Context: !in_interrupt ()
677 * Retrieves a string, encoded using UTF-16LE (Unicode, 16 bits per character,
678 * in little-endian byte order).
679 * The usb_string() function will often be a convenient way to turn
680 * these strings into kernel-printable form.
682 * Strings may be referenced in device, configuration, interface, or other
683 * descriptors, and could also be used in vendor-specific ways.
685 * This call is synchronous, and may not be used in an interrupt context.
687 * Return: The number of bytes received on success, or else the status code
688 * returned by the underlying usb_control_msg() call.
690 static int usb_get_string(struct usb_device *dev, unsigned short langid,
691 unsigned char index, void *buf, int size)
696 for (i = 0; i < 3; ++i) {
697 /* retry on length 0 or stall; some devices are flakey */
698 result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
699 USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
700 (USB_DT_STRING << 8) + index, langid, buf, size,
701 USB_CTRL_GET_TIMEOUT);
702 if (result == 0 || result == -EPIPE)
704 if (result > 1 && ((u8 *) buf)[1] != USB_DT_STRING) {
713 static void usb_try_string_workarounds(unsigned char *buf, int *length)
715 int newlength, oldlength = *length;
717 for (newlength = 2; newlength + 1 < oldlength; newlength += 2)
718 if (!isprint(buf[newlength]) || buf[newlength + 1])
727 static int usb_string_sub(struct usb_device *dev, unsigned int langid,
728 unsigned int index, unsigned char *buf)
732 /* Try to read the string descriptor by asking for the maximum
733 * possible number of bytes */
734 if (dev->quirks & USB_QUIRK_STRING_FETCH_255)
737 rc = usb_get_string(dev, langid, index, buf, 255);
739 /* If that failed try to read the descriptor length, then
740 * ask for just that many bytes */
742 rc = usb_get_string(dev, langid, index, buf, 2);
744 rc = usb_get_string(dev, langid, index, buf, buf[0]);
748 if (!buf[0] && !buf[1])
749 usb_try_string_workarounds(buf, &rc);
751 /* There might be extra junk at the end of the descriptor */
755 rc = rc - (rc & 1); /* force a multiple of two */
759 rc = (rc < 0 ? rc : -EINVAL);
764 static int usb_get_langid(struct usb_device *dev, unsigned char *tbuf)
768 if (dev->have_langid)
771 if (dev->string_langid < 0)
774 err = usb_string_sub(dev, 0, 0, tbuf);
776 /* If the string was reported but is malformed, default to english
778 if (err == -ENODATA || (err > 0 && err < 4)) {
779 dev->string_langid = 0x0409;
780 dev->have_langid = 1;
782 "language id specifier not provided by device, defaulting to English\n");
786 /* In case of all other errors, we assume the device is not able to
787 * deal with strings at all. Set string_langid to -1 in order to
788 * prevent any string to be retrieved from the device */
790 dev_err(&dev->dev, "string descriptor 0 read error: %d\n",
792 dev->string_langid = -1;
796 /* always use the first langid listed */
797 dev->string_langid = tbuf[2] | (tbuf[3] << 8);
798 dev->have_langid = 1;
799 dev_dbg(&dev->dev, "default language 0x%04x\n",
805 * usb_string - returns UTF-8 version of a string descriptor
806 * @dev: the device whose string descriptor is being retrieved
807 * @index: the number of the descriptor
808 * @buf: where to put the string
809 * @size: how big is "buf"?
810 * Context: !in_interrupt ()
812 * This converts the UTF-16LE encoded strings returned by devices, from
813 * usb_get_string_descriptor(), to null-terminated UTF-8 encoded ones
814 * that are more usable in most kernel contexts. Note that this function
815 * chooses strings in the first language supported by the device.
817 * This call is synchronous, and may not be used in an interrupt context.
819 * Return: length of the string (>= 0) or usb_control_msg status (< 0).
821 int usb_string(struct usb_device *dev, int index, char *buf, size_t size)
826 if (dev->state == USB_STATE_SUSPENDED)
827 return -EHOSTUNREACH;
828 if (size <= 0 || !buf)
831 if (index <= 0 || index >= 256)
833 tbuf = kmalloc(256, GFP_NOIO);
837 err = usb_get_langid(dev, tbuf);
841 err = usb_string_sub(dev, dev->string_langid, index, tbuf);
845 size--; /* leave room for trailing NULL char in output buffer */
846 err = utf16s_to_utf8s((wchar_t *) &tbuf[2], (err - 2) / 2,
847 UTF16_LITTLE_ENDIAN, buf, size);
850 if (tbuf[1] != USB_DT_STRING)
852 "wrong descriptor type %02x for string %d (\"%s\")\n",
853 tbuf[1], index, buf);
859 EXPORT_SYMBOL_GPL(usb_string);
861 /* one UTF-8-encoded 16-bit character has at most three bytes */
862 #define MAX_USB_STRING_SIZE (127 * 3 + 1)
865 * usb_cache_string - read a string descriptor and cache it for later use
866 * @udev: the device whose string descriptor is being read
867 * @index: the descriptor index
869 * Return: A pointer to a kmalloc'ed buffer containing the descriptor string,
870 * or %NULL if the index is 0 or the string could not be read.
872 char *usb_cache_string(struct usb_device *udev, int index)
875 char *smallbuf = NULL;
881 buf = kmalloc(MAX_USB_STRING_SIZE, GFP_NOIO);
883 len = usb_string(udev, index, buf, MAX_USB_STRING_SIZE);
885 smallbuf = kmalloc(++len, GFP_NOIO);
888 memcpy(smallbuf, buf, len);
896 * usb_get_device_descriptor - (re)reads the device descriptor (usbcore)
897 * @dev: the device whose device descriptor is being updated
898 * @size: how much of the descriptor to read
899 * Context: !in_interrupt ()
901 * Updates the copy of the device descriptor stored in the device structure,
902 * which dedicates space for this purpose.
904 * Not exported, only for use by the core. If drivers really want to read
905 * the device descriptor directly, they can call usb_get_descriptor() with
906 * type = USB_DT_DEVICE and index = 0.
908 * This call is synchronous, and may not be used in an interrupt context.
910 * Return: The number of bytes received on success, or else the status code
911 * returned by the underlying usb_control_msg() call.
913 int usb_get_device_descriptor(struct usb_device *dev, unsigned int size)
915 struct usb_device_descriptor *desc;
918 if (size > sizeof(*desc))
920 desc = kmalloc(sizeof(*desc), GFP_NOIO);
924 ret = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, size);
926 memcpy(&dev->descriptor, desc, size);
932 * usb_get_status - issues a GET_STATUS call
933 * @dev: the device whose status is being checked
934 * @type: USB_RECIP_*; for device, interface, or endpoint
935 * @target: zero (for device), else interface or endpoint number
936 * @data: pointer to two bytes of bitmap data
937 * Context: !in_interrupt ()
939 * Returns device, interface, or endpoint status. Normally only of
940 * interest to see if the device is self powered, or has enabled the
941 * remote wakeup facility; or whether a bulk or interrupt endpoint
942 * is halted ("stalled").
944 * Bits in these status bitmaps are set using the SET_FEATURE request,
945 * and cleared using the CLEAR_FEATURE request. The usb_clear_halt()
946 * function should be used to clear halt ("stall") status.
948 * This call is synchronous, and may not be used in an interrupt context.
950 * Returns 0 and the status value in *@data (in host byte order) on success,
951 * or else the status code from the underlying usb_control_msg() call.
953 int usb_get_status(struct usb_device *dev, int type, int target, void *data)
956 __le16 *status = kmalloc(sizeof(*status), GFP_KERNEL);
961 ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
962 USB_REQ_GET_STATUS, USB_DIR_IN | type, 0, target, status,
963 sizeof(*status), USB_CTRL_GET_TIMEOUT);
966 *(u16 *) data = le16_to_cpu(*status);
968 } else if (ret >= 0) {
974 EXPORT_SYMBOL_GPL(usb_get_status);
977 * usb_clear_halt - tells device to clear endpoint halt/stall condition
978 * @dev: device whose endpoint is halted
979 * @pipe: endpoint "pipe" being cleared
980 * Context: !in_interrupt ()
982 * This is used to clear halt conditions for bulk and interrupt endpoints,
983 * as reported by URB completion status. Endpoints that are halted are
984 * sometimes referred to as being "stalled". Such endpoints are unable
985 * to transmit or receive data until the halt status is cleared. Any URBs
986 * queued for such an endpoint should normally be unlinked by the driver
987 * before clearing the halt condition, as described in sections 5.7.5
988 * and 5.8.5 of the USB 2.0 spec.
990 * Note that control and isochronous endpoints don't halt, although control
991 * endpoints report "protocol stall" (for unsupported requests) using the
992 * same status code used to report a true stall.
994 * This call is synchronous, and may not be used in an interrupt context.
996 * Return: Zero on success, or else the status code returned by the
997 * underlying usb_control_msg() call.
999 int usb_clear_halt(struct usb_device *dev, int pipe)
1002 int endp = usb_pipeendpoint(pipe);
1004 if (usb_pipein(pipe))
1007 /* we don't care if it wasn't halted first. in fact some devices
1008 * (like some ibmcam model 1 units) seem to expect hosts to make
1009 * this request for iso endpoints, which can't halt!
1011 result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
1012 USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
1013 USB_ENDPOINT_HALT, endp, NULL, 0,
1014 USB_CTRL_SET_TIMEOUT);
1016 /* don't un-halt or force to DATA0 except on success */
1020 /* NOTE: seems like Microsoft and Apple don't bother verifying
1021 * the clear "took", so some devices could lock up if you check...
1022 * such as the Hagiwara FlashGate DUAL. So we won't bother.
1024 * NOTE: make sure the logic here doesn't diverge much from
1025 * the copy in usb-storage, for as long as we need two copies.
1028 usb_reset_endpoint(dev, endp);
1032 EXPORT_SYMBOL_GPL(usb_clear_halt);
1034 static int create_intf_ep_devs(struct usb_interface *intf)
1036 struct usb_device *udev = interface_to_usbdev(intf);
1037 struct usb_host_interface *alt = intf->cur_altsetting;
1040 if (intf->ep_devs_created || intf->unregistering)
1043 for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1044 (void) usb_create_ep_devs(&intf->dev, &alt->endpoint[i], udev);
1045 intf->ep_devs_created = 1;
1049 static void remove_intf_ep_devs(struct usb_interface *intf)
1051 struct usb_host_interface *alt = intf->cur_altsetting;
1054 if (!intf->ep_devs_created)
1057 for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1058 usb_remove_ep_devs(&alt->endpoint[i]);
1059 intf->ep_devs_created = 0;
1063 * usb_disable_endpoint -- Disable an endpoint by address
1064 * @dev: the device whose endpoint is being disabled
1065 * @epaddr: the endpoint's address. Endpoint number for output,
1066 * endpoint number + USB_DIR_IN for input
1067 * @reset_hardware: flag to erase any endpoint state stored in the
1068 * controller hardware
1070 * Disables the endpoint for URB submission and nukes all pending URBs.
1071 * If @reset_hardware is set then also deallocates hcd/hardware state
1074 void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr,
1075 bool reset_hardware)
1077 unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
1078 struct usb_host_endpoint *ep;
1083 if (usb_endpoint_out(epaddr)) {
1084 ep = dev->ep_out[epnum];
1085 if (reset_hardware && epnum != 0)
1086 dev->ep_out[epnum] = NULL;
1088 ep = dev->ep_in[epnum];
1089 if (reset_hardware && epnum != 0)
1090 dev->ep_in[epnum] = NULL;
1094 usb_hcd_flush_endpoint(dev, ep);
1096 usb_hcd_disable_endpoint(dev, ep);
1101 * usb_reset_endpoint - Reset an endpoint's state.
1102 * @dev: the device whose endpoint is to be reset
1103 * @epaddr: the endpoint's address. Endpoint number for output,
1104 * endpoint number + USB_DIR_IN for input
1106 * Resets any host-side endpoint state such as the toggle bit,
1107 * sequence number or current window.
1109 void usb_reset_endpoint(struct usb_device *dev, unsigned int epaddr)
1111 unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
1112 struct usb_host_endpoint *ep;
1114 if (usb_endpoint_out(epaddr))
1115 ep = dev->ep_out[epnum];
1117 ep = dev->ep_in[epnum];
1119 usb_hcd_reset_endpoint(dev, ep);
1121 EXPORT_SYMBOL_GPL(usb_reset_endpoint);
1125 * usb_disable_interface -- Disable all endpoints for an interface
1126 * @dev: the device whose interface is being disabled
1127 * @intf: pointer to the interface descriptor
1128 * @reset_hardware: flag to erase any endpoint state stored in the
1129 * controller hardware
1131 * Disables all the endpoints for the interface's current altsetting.
1133 void usb_disable_interface(struct usb_device *dev, struct usb_interface *intf,
1134 bool reset_hardware)
1136 struct usb_host_interface *alt = intf->cur_altsetting;
1139 for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
1140 usb_disable_endpoint(dev,
1141 alt->endpoint[i].desc.bEndpointAddress,
1147 * usb_disable_device_endpoints -- Disable all endpoints for a device
1148 * @dev: the device whose endpoints are being disabled
1149 * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
1151 static void usb_disable_device_endpoints(struct usb_device *dev, int skip_ep0)
1153 struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1156 if (hcd->driver->check_bandwidth) {
1157 /* First pass: Cancel URBs, leave endpoint pointers intact. */
1158 for (i = skip_ep0; i < 16; ++i) {
1159 usb_disable_endpoint(dev, i, false);
1160 usb_disable_endpoint(dev, i + USB_DIR_IN, false);
1162 /* Remove endpoints from the host controller internal state */
1163 mutex_lock(hcd->bandwidth_mutex);
1164 usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
1165 mutex_unlock(hcd->bandwidth_mutex);
1167 /* Second pass: remove endpoint pointers */
1168 for (i = skip_ep0; i < 16; ++i) {
1169 usb_disable_endpoint(dev, i, true);
1170 usb_disable_endpoint(dev, i + USB_DIR_IN, true);
1175 * usb_disable_device - Disable all the endpoints for a USB device
1176 * @dev: the device whose endpoints are being disabled
1177 * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
1179 * Disables all the device's endpoints, potentially including endpoint 0.
1180 * Deallocates hcd/hardware state for the endpoints (nuking all or most
1181 * pending urbs) and usbcore state for the interfaces, so that usbcore
1182 * must usb_set_configuration() before any interfaces could be used.
1184 void usb_disable_device(struct usb_device *dev, int skip_ep0)
1188 /* getting rid of interfaces will disconnect
1189 * any drivers bound to them (a key side effect)
1191 if (dev->actconfig) {
1193 * FIXME: In order to avoid self-deadlock involving the
1194 * bandwidth_mutex, we have to mark all the interfaces
1195 * before unregistering any of them.
1197 for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++)
1198 dev->actconfig->interface[i]->unregistering = 1;
1200 for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
1201 struct usb_interface *interface;
1203 /* remove this interface if it has been registered */
1204 interface = dev->actconfig->interface[i];
1205 if (!device_is_registered(&interface->dev))
1207 dev_dbg(&dev->dev, "unregistering interface %s\n",
1208 dev_name(&interface->dev));
1209 remove_intf_ep_devs(interface);
1210 device_del(&interface->dev);
1213 /* Now that the interfaces are unbound, nobody should
1214 * try to access them.
1216 for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
1217 put_device(&dev->actconfig->interface[i]->dev);
1218 dev->actconfig->interface[i] = NULL;
1221 usb_disable_usb2_hardware_lpm(dev);
1222 usb_unlocked_disable_lpm(dev);
1223 usb_disable_ltm(dev);
1225 dev->actconfig = NULL;
1226 if (dev->state == USB_STATE_CONFIGURED)
1227 usb_set_device_state(dev, USB_STATE_ADDRESS);
1230 dev_dbg(&dev->dev, "%s nuking %s URBs\n", __func__,
1231 skip_ep0 ? "non-ep0" : "all");
1233 usb_disable_device_endpoints(dev, skip_ep0);
1237 * usb_enable_endpoint - Enable an endpoint for USB communications
1238 * @dev: the device whose interface is being enabled
1240 * @reset_ep: flag to reset the endpoint state
1242 * Resets the endpoint state if asked, and sets dev->ep_{in,out} pointers.
1243 * For control endpoints, both the input and output sides are handled.
1245 void usb_enable_endpoint(struct usb_device *dev, struct usb_host_endpoint *ep,
1248 int epnum = usb_endpoint_num(&ep->desc);
1249 int is_out = usb_endpoint_dir_out(&ep->desc);
1250 int is_control = usb_endpoint_xfer_control(&ep->desc);
1253 usb_hcd_reset_endpoint(dev, ep);
1254 if (is_out || is_control)
1255 dev->ep_out[epnum] = ep;
1256 if (!is_out || is_control)
1257 dev->ep_in[epnum] = ep;
1262 * usb_enable_interface - Enable all the endpoints for an interface
1263 * @dev: the device whose interface is being enabled
1264 * @intf: pointer to the interface descriptor
1265 * @reset_eps: flag to reset the endpoints' state
1267 * Enables all the endpoints for the interface's current altsetting.
1269 void usb_enable_interface(struct usb_device *dev,
1270 struct usb_interface *intf, bool reset_eps)
1272 struct usb_host_interface *alt = intf->cur_altsetting;
1275 for (i = 0; i < alt->desc.bNumEndpoints; ++i)
1276 usb_enable_endpoint(dev, &alt->endpoint[i], reset_eps);
1280 * usb_set_interface - Makes a particular alternate setting be current
1281 * @dev: the device whose interface is being updated
1282 * @interface: the interface being updated
1283 * @alternate: the setting being chosen.
1284 * Context: !in_interrupt ()
1286 * This is used to enable data transfers on interfaces that may not
1287 * be enabled by default. Not all devices support such configurability.
1288 * Only the driver bound to an interface may change its setting.
1290 * Within any given configuration, each interface may have several
1291 * alternative settings. These are often used to control levels of
1292 * bandwidth consumption. For example, the default setting for a high
1293 * speed interrupt endpoint may not send more than 64 bytes per microframe,
1294 * while interrupt transfers of up to 3KBytes per microframe are legal.
1295 * Also, isochronous endpoints may never be part of an
1296 * interface's default setting. To access such bandwidth, alternate
1297 * interface settings must be made current.
1299 * Note that in the Linux USB subsystem, bandwidth associated with
1300 * an endpoint in a given alternate setting is not reserved until an URB
1301 * is submitted that needs that bandwidth. Some other operating systems
1302 * allocate bandwidth early, when a configuration is chosen.
1304 * xHCI reserves bandwidth and configures the alternate setting in
1305 * usb_hcd_alloc_bandwidth(). If it fails the original interface altsetting
1306 * may be disabled. Drivers cannot rely on any particular alternate
1307 * setting being in effect after a failure.
1309 * This call is synchronous, and may not be used in an interrupt context.
1310 * Also, drivers must not change altsettings while urbs are scheduled for
1311 * endpoints in that interface; all such urbs must first be completed
1312 * (perhaps forced by unlinking).
1314 * Return: Zero on success, or else the status code returned by the
1315 * underlying usb_control_msg() call.
1317 int usb_set_interface(struct usb_device *dev, int interface, int alternate)
1319 struct usb_interface *iface;
1320 struct usb_host_interface *alt;
1321 struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1322 int i, ret, manual = 0;
1323 unsigned int epaddr;
1326 if (dev->state == USB_STATE_SUSPENDED)
1327 return -EHOSTUNREACH;
1329 iface = usb_ifnum_to_if(dev, interface);
1331 dev_dbg(&dev->dev, "selecting invalid interface %d\n",
1335 if (iface->unregistering)
1338 alt = usb_altnum_to_altsetting(iface, alternate);
1340 dev_warn(&dev->dev, "selecting invalid altsetting %d\n",
1345 * usb3 hosts configure the interface in usb_hcd_alloc_bandwidth,
1346 * including freeing dropped endpoint ring buffers.
1347 * Make sure the interface endpoints are flushed before that
1349 usb_disable_interface(dev, iface, false);
1351 /* Make sure we have enough bandwidth for this alternate interface.
1352 * Remove the current alt setting and add the new alt setting.
1354 mutex_lock(hcd->bandwidth_mutex);
1355 /* Disable LPM, and re-enable it once the new alt setting is installed,
1356 * so that the xHCI driver can recalculate the U1/U2 timeouts.
1358 if (usb_disable_lpm(dev)) {
1359 dev_err(&iface->dev, "%s Failed to disable LPM\n.", __func__);
1360 mutex_unlock(hcd->bandwidth_mutex);
1363 /* Changing alt-setting also frees any allocated streams */
1364 for (i = 0; i < iface->cur_altsetting->desc.bNumEndpoints; i++)
1365 iface->cur_altsetting->endpoint[i].streams = 0;
1367 ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt);
1369 dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n",
1371 usb_enable_lpm(dev);
1372 mutex_unlock(hcd->bandwidth_mutex);
1376 if (dev->quirks & USB_QUIRK_NO_SET_INTF)
1379 ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
1380 USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE,
1381 alternate, interface, NULL, 0, 5000);
1383 /* 9.4.10 says devices don't need this and are free to STALL the
1384 * request if the interface only has one alternate setting.
1386 if (ret == -EPIPE && iface->num_altsetting == 1) {
1388 "manual set_interface for iface %d, alt %d\n",
1389 interface, alternate);
1391 } else if (ret < 0) {
1392 /* Re-instate the old alt setting */
1393 usb_hcd_alloc_bandwidth(dev, NULL, alt, iface->cur_altsetting);
1394 usb_enable_lpm(dev);
1395 mutex_unlock(hcd->bandwidth_mutex);
1398 mutex_unlock(hcd->bandwidth_mutex);
1400 /* FIXME drivers shouldn't need to replicate/bugfix the logic here
1401 * when they implement async or easily-killable versions of this or
1402 * other "should-be-internal" functions (like clear_halt).
1403 * should hcd+usbcore postprocess control requests?
1406 /* prevent submissions using previous endpoint settings */
1407 if (iface->cur_altsetting != alt) {
1408 remove_intf_ep_devs(iface);
1409 usb_remove_sysfs_intf_files(iface);
1411 usb_disable_interface(dev, iface, true);
1413 iface->cur_altsetting = alt;
1415 /* Now that the interface is installed, re-enable LPM. */
1416 usb_unlocked_enable_lpm(dev);
1418 /* If the interface only has one altsetting and the device didn't
1419 * accept the request, we attempt to carry out the equivalent action
1420 * by manually clearing the HALT feature for each endpoint in the
1424 for (i = 0; i < alt->desc.bNumEndpoints; i++) {
1425 epaddr = alt->endpoint[i].desc.bEndpointAddress;
1426 pipe = __create_pipe(dev,
1427 USB_ENDPOINT_NUMBER_MASK & epaddr) |
1428 (usb_endpoint_out(epaddr) ?
1429 USB_DIR_OUT : USB_DIR_IN);
1431 usb_clear_halt(dev, pipe);
1435 /* 9.1.1.5: reset toggles for all endpoints in the new altsetting
1438 * Despite EP0 is always present in all interfaces/AS, the list of
1439 * endpoints from the descriptor does not contain EP0. Due to its
1440 * omnipresence one might expect EP0 being considered "affected" by
1441 * any SetInterface request and hence assume toggles need to be reset.
1442 * However, EP0 toggles are re-synced for every individual transfer
1443 * during the SETUP stage - hence EP0 toggles are "don't care" here.
1444 * (Likewise, EP0 never "halts" on well designed devices.)
1446 usb_enable_interface(dev, iface, true);
1447 if (device_is_registered(&iface->dev)) {
1448 usb_create_sysfs_intf_files(iface);
1449 create_intf_ep_devs(iface);
1453 EXPORT_SYMBOL_GPL(usb_set_interface);
1456 * usb_reset_configuration - lightweight device reset
1457 * @dev: the device whose configuration is being reset
1459 * This issues a standard SET_CONFIGURATION request to the device using
1460 * the current configuration. The effect is to reset most USB-related
1461 * state in the device, including interface altsettings (reset to zero),
1462 * endpoint halts (cleared), and endpoint state (only for bulk and interrupt
1463 * endpoints). Other usbcore state is unchanged, including bindings of
1464 * usb device drivers to interfaces.
1466 * Because this affects multiple interfaces, avoid using this with composite
1467 * (multi-interface) devices. Instead, the driver for each interface may
1468 * use usb_set_interface() on the interfaces it claims. Be careful though;
1469 * some devices don't support the SET_INTERFACE request, and others won't
1470 * reset all the interface state (notably endpoint state). Resetting the whole
1471 * configuration would affect other drivers' interfaces.
1473 * The caller must own the device lock.
1475 * Return: Zero on success, else a negative error code.
1477 * If this routine fails the device will probably be in an unusable state
1478 * with endpoints disabled, and interfaces only partially enabled.
1480 int usb_reset_configuration(struct usb_device *dev)
1483 struct usb_host_config *config;
1484 struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1486 if (dev->state == USB_STATE_SUSPENDED)
1487 return -EHOSTUNREACH;
1489 /* caller must have locked the device and must own
1490 * the usb bus readlock (so driver bindings are stable);
1491 * calls during probe() are fine
1494 usb_disable_device_endpoints(dev, 1); /* skip ep0*/
1496 config = dev->actconfig;
1498 mutex_lock(hcd->bandwidth_mutex);
1499 /* Disable LPM, and re-enable it once the configuration is reset, so
1500 * that the xHCI driver can recalculate the U1/U2 timeouts.
1502 if (usb_disable_lpm(dev)) {
1503 dev_err(&dev->dev, "%s Failed to disable LPM\n.", __func__);
1504 mutex_unlock(hcd->bandwidth_mutex);
1508 /* xHCI adds all endpoints in usb_hcd_alloc_bandwidth */
1509 retval = usb_hcd_alloc_bandwidth(dev, config, NULL, NULL);
1511 usb_enable_lpm(dev);
1512 mutex_unlock(hcd->bandwidth_mutex);
1515 retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
1516 USB_REQ_SET_CONFIGURATION, 0,
1517 config->desc.bConfigurationValue, 0,
1518 NULL, 0, USB_CTRL_SET_TIMEOUT);
1520 usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
1521 usb_enable_lpm(dev);
1522 mutex_unlock(hcd->bandwidth_mutex);
1525 mutex_unlock(hcd->bandwidth_mutex);
1527 /* re-init hc/hcd interface/endpoint state */
1528 for (i = 0; i < config->desc.bNumInterfaces; i++) {
1529 struct usb_interface *intf = config->interface[i];
1530 struct usb_host_interface *alt;
1532 alt = usb_altnum_to_altsetting(intf, 0);
1534 /* No altsetting 0? We'll assume the first altsetting.
1535 * We could use a GetInterface call, but if a device is
1536 * so non-compliant that it doesn't have altsetting 0
1537 * then I wouldn't trust its reply anyway.
1540 alt = &intf->altsetting[0];
1542 if (alt != intf->cur_altsetting) {
1543 remove_intf_ep_devs(intf);
1544 usb_remove_sysfs_intf_files(intf);
1546 intf->cur_altsetting = alt;
1547 usb_enable_interface(dev, intf, true);
1548 if (device_is_registered(&intf->dev)) {
1549 usb_create_sysfs_intf_files(intf);
1550 create_intf_ep_devs(intf);
1553 /* Now that the interfaces are installed, re-enable LPM. */
1554 usb_unlocked_enable_lpm(dev);
1557 EXPORT_SYMBOL_GPL(usb_reset_configuration);
1559 static void usb_release_interface(struct device *dev)
1561 struct usb_interface *intf = to_usb_interface(dev);
1562 struct usb_interface_cache *intfc =
1563 altsetting_to_usb_interface_cache(intf->altsetting);
1565 kref_put(&intfc->ref, usb_release_interface_cache);
1566 usb_put_dev(interface_to_usbdev(intf));
1571 * usb_deauthorize_interface - deauthorize an USB interface
1573 * @intf: USB interface structure
1575 void usb_deauthorize_interface(struct usb_interface *intf)
1577 struct device *dev = &intf->dev;
1579 device_lock(dev->parent);
1581 if (intf->authorized) {
1583 intf->authorized = 0;
1586 usb_forced_unbind_intf(intf);
1589 device_unlock(dev->parent);
1593 * usb_authorize_interface - authorize an USB interface
1595 * @intf: USB interface structure
1597 void usb_authorize_interface(struct usb_interface *intf)
1599 struct device *dev = &intf->dev;
1601 if (!intf->authorized) {
1603 intf->authorized = 1; /* authorize interface */
1608 static int usb_if_uevent(struct device *dev, struct kobj_uevent_env *env)
1610 struct usb_device *usb_dev;
1611 struct usb_interface *intf;
1612 struct usb_host_interface *alt;
1614 intf = to_usb_interface(dev);
1615 usb_dev = interface_to_usbdev(intf);
1616 alt = intf->cur_altsetting;
1618 if (add_uevent_var(env, "INTERFACE=%d/%d/%d",
1619 alt->desc.bInterfaceClass,
1620 alt->desc.bInterfaceSubClass,
1621 alt->desc.bInterfaceProtocol))
1624 if (add_uevent_var(env,
1626 "v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02Xin%02X",
1627 le16_to_cpu(usb_dev->descriptor.idVendor),
1628 le16_to_cpu(usb_dev->descriptor.idProduct),
1629 le16_to_cpu(usb_dev->descriptor.bcdDevice),
1630 usb_dev->descriptor.bDeviceClass,
1631 usb_dev->descriptor.bDeviceSubClass,
1632 usb_dev->descriptor.bDeviceProtocol,
1633 alt->desc.bInterfaceClass,
1634 alt->desc.bInterfaceSubClass,
1635 alt->desc.bInterfaceProtocol,
1636 alt->desc.bInterfaceNumber))
1642 struct device_type usb_if_device_type = {
1643 .name = "usb_interface",
1644 .release = usb_release_interface,
1645 .uevent = usb_if_uevent,
1648 static struct usb_interface_assoc_descriptor *find_iad(struct usb_device *dev,
1649 struct usb_host_config *config,
1652 struct usb_interface_assoc_descriptor *retval = NULL;
1653 struct usb_interface_assoc_descriptor *intf_assoc;
1658 for (i = 0; (i < USB_MAXIADS && config->intf_assoc[i]); i++) {
1659 intf_assoc = config->intf_assoc[i];
1660 if (intf_assoc->bInterfaceCount == 0)
1663 first_intf = intf_assoc->bFirstInterface;
1664 last_intf = first_intf + (intf_assoc->bInterfaceCount - 1);
1665 if (inum >= first_intf && inum <= last_intf) {
1667 retval = intf_assoc;
1669 dev_err(&dev->dev, "Interface #%d referenced"
1670 " by multiple IADs\n", inum);
1679 * Internal function to queue a device reset
1680 * See usb_queue_reset_device() for more details
1682 static void __usb_queue_reset_device(struct work_struct *ws)
1685 struct usb_interface *iface =
1686 container_of(ws, struct usb_interface, reset_ws);
1687 struct usb_device *udev = interface_to_usbdev(iface);
1689 rc = usb_lock_device_for_reset(udev, iface);
1691 usb_reset_device(udev);
1692 usb_unlock_device(udev);
1694 usb_put_intf(iface); /* Undo _get_ in usb_queue_reset_device() */
1699 * usb_set_configuration - Makes a particular device setting be current
1700 * @dev: the device whose configuration is being updated
1701 * @configuration: the configuration being chosen.
1702 * Context: !in_interrupt(), caller owns the device lock
1704 * This is used to enable non-default device modes. Not all devices
1705 * use this kind of configurability; many devices only have one
1708 * @configuration is the value of the configuration to be installed.
1709 * According to the USB spec (e.g. section 9.1.1.5), configuration values
1710 * must be non-zero; a value of zero indicates that the device in
1711 * unconfigured. However some devices erroneously use 0 as one of their
1712 * configuration values. To help manage such devices, this routine will
1713 * accept @configuration = -1 as indicating the device should be put in
1714 * an unconfigured state.
1716 * USB device configurations may affect Linux interoperability,
1717 * power consumption and the functionality available. For example,
1718 * the default configuration is limited to using 100mA of bus power,
1719 * so that when certain device functionality requires more power,
1720 * and the device is bus powered, that functionality should be in some
1721 * non-default device configuration. Other device modes may also be
1722 * reflected as configuration options, such as whether two ISDN
1723 * channels are available independently; and choosing between open
1724 * standard device protocols (like CDC) or proprietary ones.
1726 * Note that a non-authorized device (dev->authorized == 0) will only
1727 * be put in unconfigured mode.
1729 * Note that USB has an additional level of device configurability,
1730 * associated with interfaces. That configurability is accessed using
1731 * usb_set_interface().
1733 * This call is synchronous. The calling context must be able to sleep,
1734 * must own the device lock, and must not hold the driver model's USB
1735 * bus mutex; usb interface driver probe() methods cannot use this routine.
1737 * Returns zero on success, or else the status code returned by the
1738 * underlying call that failed. On successful completion, each interface
1739 * in the original device configuration has been destroyed, and each one
1740 * in the new configuration has been probed by all relevant usb device
1741 * drivers currently known to the kernel.
1743 int usb_set_configuration(struct usb_device *dev, int configuration)
1746 struct usb_host_config *cp = NULL;
1747 struct usb_interface **new_interfaces = NULL;
1748 struct usb_hcd *hcd = bus_to_hcd(dev->bus);
1751 if (dev->authorized == 0 || configuration == -1)
1754 for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
1755 if (dev->config[i].desc.bConfigurationValue ==
1757 cp = &dev->config[i];
1762 if ((!cp && configuration != 0))
1765 /* The USB spec says configuration 0 means unconfigured.
1766 * But if a device includes a configuration numbered 0,
1767 * we will accept it as a correctly configured state.
1768 * Use -1 if you really want to unconfigure the device.
1770 if (cp && configuration == 0)
1771 dev_warn(&dev->dev, "config 0 descriptor??\n");
1773 /* Allocate memory for new interfaces before doing anything else,
1774 * so that if we run out then nothing will have changed. */
1777 nintf = cp->desc.bNumInterfaces;
1778 new_interfaces = kmalloc(nintf * sizeof(*new_interfaces),
1780 if (!new_interfaces)
1783 for (; n < nintf; ++n) {
1784 new_interfaces[n] = kzalloc(
1785 sizeof(struct usb_interface),
1787 if (!new_interfaces[n]) {
1791 kfree(new_interfaces[n]);
1792 kfree(new_interfaces);
1797 i = dev->bus_mA - usb_get_max_power(dev, cp);
1799 dev_warn(&dev->dev, "new config #%d exceeds power "
1804 /* Wake up the device so we can send it the Set-Config request */
1805 ret = usb_autoresume_device(dev);
1807 goto free_interfaces;
1809 /* if it's already configured, clear out old state first.
1810 * getting rid of old interfaces means unbinding their drivers.
1812 if (dev->state != USB_STATE_ADDRESS)
1813 usb_disable_device(dev, 1); /* Skip ep0 */
1815 /* Get rid of pending async Set-Config requests for this device */
1816 cancel_async_set_config(dev);
1818 /* Make sure we have bandwidth (and available HCD resources) for this
1819 * configuration. Remove endpoints from the schedule if we're dropping
1820 * this configuration to set configuration 0. After this point, the
1821 * host controller will not allow submissions to dropped endpoints. If
1822 * this call fails, the device state is unchanged.
1824 mutex_lock(hcd->bandwidth_mutex);
1825 /* Disable LPM, and re-enable it once the new configuration is
1826 * installed, so that the xHCI driver can recalculate the U1/U2
1829 if (dev->actconfig && usb_disable_lpm(dev)) {
1830 dev_err(&dev->dev, "%s Failed to disable LPM\n.", __func__);
1831 mutex_unlock(hcd->bandwidth_mutex);
1833 goto free_interfaces;
1835 ret = usb_hcd_alloc_bandwidth(dev, cp, NULL, NULL);
1838 usb_enable_lpm(dev);
1839 mutex_unlock(hcd->bandwidth_mutex);
1840 usb_autosuspend_device(dev);
1841 goto free_interfaces;
1845 * Initialize the new interface structures and the
1846 * hc/hcd/usbcore interface/endpoint state.
1848 for (i = 0; i < nintf; ++i) {
1849 struct usb_interface_cache *intfc;
1850 struct usb_interface *intf;
1851 struct usb_host_interface *alt;
1853 cp->interface[i] = intf = new_interfaces[i];
1854 intfc = cp->intf_cache[i];
1855 intf->altsetting = intfc->altsetting;
1856 intf->num_altsetting = intfc->num_altsetting;
1857 intf->authorized = !!HCD_INTF_AUTHORIZED(hcd);
1858 kref_get(&intfc->ref);
1860 alt = usb_altnum_to_altsetting(intf, 0);
1862 /* No altsetting 0? We'll assume the first altsetting.
1863 * We could use a GetInterface call, but if a device is
1864 * so non-compliant that it doesn't have altsetting 0
1865 * then I wouldn't trust its reply anyway.
1868 alt = &intf->altsetting[0];
1871 find_iad(dev, cp, alt->desc.bInterfaceNumber);
1872 intf->cur_altsetting = alt;
1873 usb_enable_interface(dev, intf, true);
1874 intf->dev.parent = &dev->dev;
1875 intf->dev.driver = NULL;
1876 intf->dev.bus = &usb_bus_type;
1877 intf->dev.type = &usb_if_device_type;
1878 intf->dev.groups = usb_interface_groups;
1880 * Please refer to usb_alloc_dev() to see why we set
1881 * dma_mask and dma_pfn_offset.
1883 intf->dev.dma_mask = dev->dev.dma_mask;
1884 intf->dev.dma_pfn_offset = dev->dev.dma_pfn_offset;
1885 INIT_WORK(&intf->reset_ws, __usb_queue_reset_device);
1887 device_initialize(&intf->dev);
1888 pm_runtime_no_callbacks(&intf->dev);
1889 dev_set_name(&intf->dev, "%d-%s:%d.%d",
1890 dev->bus->busnum, dev->devpath,
1891 configuration, alt->desc.bInterfaceNumber);
1894 kfree(new_interfaces);
1896 ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
1897 USB_REQ_SET_CONFIGURATION, 0, configuration, 0,
1898 NULL, 0, USB_CTRL_SET_TIMEOUT);
1899 if (ret < 0 && cp) {
1901 * All the old state is gone, so what else can we do?
1902 * The device is probably useless now anyway.
1904 usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
1905 for (i = 0; i < nintf; ++i) {
1906 usb_disable_interface(dev, cp->interface[i], true);
1907 put_device(&cp->interface[i]->dev);
1908 cp->interface[i] = NULL;
1913 dev->actconfig = cp;
1914 mutex_unlock(hcd->bandwidth_mutex);
1917 usb_set_device_state(dev, USB_STATE_ADDRESS);
1919 /* Leave LPM disabled while the device is unconfigured. */
1920 usb_autosuspend_device(dev);
1923 usb_set_device_state(dev, USB_STATE_CONFIGURED);
1925 if (cp->string == NULL &&
1926 !(dev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS))
1927 cp->string = usb_cache_string(dev, cp->desc.iConfiguration);
1929 /* Now that the interfaces are installed, re-enable LPM. */
1930 usb_unlocked_enable_lpm(dev);
1931 /* Enable LTM if it was turned off by usb_disable_device. */
1932 usb_enable_ltm(dev);
1934 /* Now that all the interfaces are set up, register them
1935 * to trigger binding of drivers to interfaces. probe()
1936 * routines may install different altsettings and may
1937 * claim() any interfaces not yet bound. Many class drivers
1938 * need that: CDC, audio, video, etc.
1940 for (i = 0; i < nintf; ++i) {
1941 struct usb_interface *intf = cp->interface[i];
1944 "adding %s (config #%d, interface %d)\n",
1945 dev_name(&intf->dev), configuration,
1946 intf->cur_altsetting->desc.bInterfaceNumber);
1947 device_enable_async_suspend(&intf->dev);
1948 ret = device_add(&intf->dev);
1950 dev_err(&dev->dev, "device_add(%s) --> %d\n",
1951 dev_name(&intf->dev), ret);
1954 create_intf_ep_devs(intf);
1957 usb_autosuspend_device(dev);
1960 EXPORT_SYMBOL_GPL(usb_set_configuration);
1962 static LIST_HEAD(set_config_list);
1963 static DEFINE_SPINLOCK(set_config_lock);
1965 struct set_config_request {
1966 struct usb_device *udev;
1968 struct work_struct work;
1969 struct list_head node;
1972 /* Worker routine for usb_driver_set_configuration() */
1973 static void driver_set_config_work(struct work_struct *work)
1975 struct set_config_request *req =
1976 container_of(work, struct set_config_request, work);
1977 struct usb_device *udev = req->udev;
1979 usb_lock_device(udev);
1980 spin_lock(&set_config_lock);
1981 list_del(&req->node);
1982 spin_unlock(&set_config_lock);
1984 if (req->config >= -1) /* Is req still valid? */
1985 usb_set_configuration(udev, req->config);
1986 usb_unlock_device(udev);
1991 /* Cancel pending Set-Config requests for a device whose configuration
1994 static void cancel_async_set_config(struct usb_device *udev)
1996 struct set_config_request *req;
1998 spin_lock(&set_config_lock);
1999 list_for_each_entry(req, &set_config_list, node) {
2000 if (req->udev == udev)
2001 req->config = -999; /* Mark as cancelled */
2003 spin_unlock(&set_config_lock);
2007 * usb_driver_set_configuration - Provide a way for drivers to change device configurations
2008 * @udev: the device whose configuration is being updated
2009 * @config: the configuration being chosen.
2010 * Context: In process context, must be able to sleep
2012 * Device interface drivers are not allowed to change device configurations.
2013 * This is because changing configurations will destroy the interface the
2014 * driver is bound to and create new ones; it would be like a floppy-disk
2015 * driver telling the computer to replace the floppy-disk drive with a
2018 * Still, in certain specialized circumstances the need may arise. This
2019 * routine gets around the normal restrictions by using a work thread to
2020 * submit the change-config request.
2022 * Return: 0 if the request was successfully queued, error code otherwise.
2023 * The caller has no way to know whether the queued request will eventually
2026 int usb_driver_set_configuration(struct usb_device *udev, int config)
2028 struct set_config_request *req;
2030 req = kmalloc(sizeof(*req), GFP_KERNEL);
2034 req->config = config;
2035 INIT_WORK(&req->work, driver_set_config_work);
2037 spin_lock(&set_config_lock);
2038 list_add(&req->node, &set_config_list);
2039 spin_unlock(&set_config_lock);
2042 schedule_work(&req->work);
2045 EXPORT_SYMBOL_GPL(usb_driver_set_configuration);
2048 * cdc_parse_cdc_header - parse the extra headers present in CDC devices
2049 * @hdr: the place to put the results of the parsing
2050 * @intf: the interface for which parsing is requested
2051 * @buffer: pointer to the extra headers to be parsed
2052 * @buflen: length of the extra headers
2054 * This evaluates the extra headers present in CDC devices which
2055 * bind the interfaces for data and control and provide details
2056 * about the capabilities of the device.
2058 * Return: number of descriptors parsed or -EINVAL
2059 * if the header is contradictory beyond salvage
2062 int cdc_parse_cdc_header(struct usb_cdc_parsed_header *hdr,
2063 struct usb_interface *intf,
2067 /* duplicates are ignored */
2068 struct usb_cdc_union_desc *union_header = NULL;
2070 /* duplicates are not tolerated */
2071 struct usb_cdc_header_desc *header = NULL;
2072 struct usb_cdc_ether_desc *ether = NULL;
2073 struct usb_cdc_mdlm_detail_desc *detail = NULL;
2074 struct usb_cdc_mdlm_desc *desc = NULL;
2076 unsigned int elength;
2079 memset(hdr, 0x00, sizeof(struct usb_cdc_parsed_header));
2080 hdr->phonet_magic_present = false;
2081 while (buflen > 0) {
2082 elength = buffer[0];
2084 dev_err(&intf->dev, "skipping garbage byte\n");
2088 if ((buflen < elength) || (elength < 3)) {
2089 dev_err(&intf->dev, "invalid descriptor buffer length\n");
2092 if (buffer[1] != USB_DT_CS_INTERFACE) {
2093 dev_err(&intf->dev, "skipping garbage\n");
2097 switch (buffer[2]) {
2098 case USB_CDC_UNION_TYPE: /* we've found it */
2099 if (elength < sizeof(struct usb_cdc_union_desc))
2102 dev_err(&intf->dev, "More than one union descriptor, skipping ...\n");
2105 union_header = (struct usb_cdc_union_desc *)buffer;
2107 case USB_CDC_COUNTRY_TYPE:
2108 if (elength < sizeof(struct usb_cdc_country_functional_desc))
2110 hdr->usb_cdc_country_functional_desc =
2111 (struct usb_cdc_country_functional_desc *)buffer;
2113 case USB_CDC_HEADER_TYPE:
2114 if (elength != sizeof(struct usb_cdc_header_desc))
2118 header = (struct usb_cdc_header_desc *)buffer;
2120 case USB_CDC_ACM_TYPE:
2121 if (elength < sizeof(struct usb_cdc_acm_descriptor))
2123 hdr->usb_cdc_acm_descriptor =
2124 (struct usb_cdc_acm_descriptor *)buffer;
2126 case USB_CDC_ETHERNET_TYPE:
2127 if (elength != sizeof(struct usb_cdc_ether_desc))
2131 ether = (struct usb_cdc_ether_desc *)buffer;
2133 case USB_CDC_CALL_MANAGEMENT_TYPE:
2134 if (elength < sizeof(struct usb_cdc_call_mgmt_descriptor))
2136 hdr->usb_cdc_call_mgmt_descriptor =
2137 (struct usb_cdc_call_mgmt_descriptor *)buffer;
2139 case USB_CDC_DMM_TYPE:
2140 if (elength < sizeof(struct usb_cdc_dmm_desc))
2142 hdr->usb_cdc_dmm_desc =
2143 (struct usb_cdc_dmm_desc *)buffer;
2145 case USB_CDC_MDLM_TYPE:
2146 if (elength < sizeof(struct usb_cdc_mdlm_desc))
2150 desc = (struct usb_cdc_mdlm_desc *)buffer;
2152 case USB_CDC_MDLM_DETAIL_TYPE:
2153 if (elength < sizeof(struct usb_cdc_mdlm_detail_desc))
2157 detail = (struct usb_cdc_mdlm_detail_desc *)buffer;
2159 case USB_CDC_NCM_TYPE:
2160 if (elength < sizeof(struct usb_cdc_ncm_desc))
2162 hdr->usb_cdc_ncm_desc = (struct usb_cdc_ncm_desc *)buffer;
2164 case USB_CDC_MBIM_TYPE:
2165 if (elength < sizeof(struct usb_cdc_mbim_desc))
2168 hdr->usb_cdc_mbim_desc = (struct usb_cdc_mbim_desc *)buffer;
2170 case USB_CDC_MBIM_EXTENDED_TYPE:
2171 if (elength < sizeof(struct usb_cdc_mbim_extended_desc))
2173 hdr->usb_cdc_mbim_extended_desc =
2174 (struct usb_cdc_mbim_extended_desc *)buffer;
2176 case CDC_PHONET_MAGIC_NUMBER:
2177 hdr->phonet_magic_present = true;
2181 * there are LOTS more CDC descriptors that
2182 * could legitimately be found here.
2184 dev_dbg(&intf->dev, "Ignoring descriptor: type %02x, length %ud\n",
2185 buffer[2], elength);
2193 hdr->usb_cdc_union_desc = union_header;
2194 hdr->usb_cdc_header_desc = header;
2195 hdr->usb_cdc_mdlm_detail_desc = detail;
2196 hdr->usb_cdc_mdlm_desc = desc;
2197 hdr->usb_cdc_ether_desc = ether;
2201 EXPORT_SYMBOL(cdc_parse_cdc_header);