2 * message.c - synchronous message handling
5 #include <linux/config.h>
6 #include <linux/pci.h> /* for scatterlist macros */
8 #include <linux/module.h>
9 #include <linux/slab.h>
10 #include <linux/init.h>
12 #include <linux/timer.h>
13 #include <linux/ctype.h>
14 #include <linux/device.h>
15 #include <asm/byteorder.h>
16 #include <asm/scatterlist.h>
18 #include "hcd.h" /* for usbcore internals */
21 static void usb_api_blocking_completion(struct urb
*urb
, struct pt_regs
*regs
)
23 complete((struct completion
*)urb
->context
);
27 static void timeout_kill(unsigned long data
)
29 struct urb
*urb
= (struct urb
*) data
;
34 // Starts urb and waits for completion or timeout
35 // note that this call is NOT interruptible, while
36 // many device driver i/o requests should be interruptible
37 static int usb_start_wait_urb(struct urb
*urb
, int timeout
, int* actual_length
)
39 struct completion done
;
40 struct timer_list timer
;
43 init_completion(&done
);
45 urb
->actual_length
= 0;
46 status
= usb_submit_urb(urb
, GFP_NOIO
);
51 timer
.expires
= jiffies
+ msecs_to_jiffies(timeout
);
52 timer
.data
= (unsigned long)urb
;
53 timer
.function
= timeout_kill
;
54 /* grr. timeout _should_ include submit delays. */
57 wait_for_completion(&done
);
59 /* note: HCDs return ETIMEDOUT for other reasons too */
60 if (status
== -ECONNRESET
) {
61 dev_dbg(&urb
->dev
->dev
,
62 "%s timed out on ep%d%s len=%d/%d\n",
64 usb_pipeendpoint(urb
->pipe
),
65 usb_pipein(urb
->pipe
) ? "in" : "out",
67 urb
->transfer_buffer_length
69 if (urb
->actual_length
> 0)
75 del_timer_sync(&timer
);
79 *actual_length
= urb
->actual_length
;
84 /*-------------------------------------------------------------------*/
85 // returns status (negative) or length (positive)
86 static int usb_internal_control_msg(struct usb_device
*usb_dev
,
88 struct usb_ctrlrequest
*cmd
,
89 void *data
, int len
, int timeout
)
95 urb
= usb_alloc_urb(0, GFP_NOIO
);
99 usb_fill_control_urb(urb
, usb_dev
, pipe
, (unsigned char *)cmd
, data
,
100 len
, usb_api_blocking_completion
, NULL
);
102 retv
= usb_start_wait_urb(urb
, timeout
, &length
);
110 * usb_control_msg - Builds a control urb, sends it off and waits for completion
111 * @dev: pointer to the usb device to send the message to
112 * @pipe: endpoint "pipe" to send the message to
113 * @request: USB message request value
114 * @requesttype: USB message request type value
115 * @value: USB message value
116 * @index: USB message index value
117 * @data: pointer to the data to send
118 * @size: length in bytes of the data to send
119 * @timeout: time in msecs to wait for the message to complete before
120 * timing out (if 0 the wait is forever)
121 * Context: !in_interrupt ()
123 * This function sends a simple control message to a specified endpoint
124 * and waits for the message to complete, or timeout.
126 * If successful, it returns the number of bytes transferred, otherwise a negative error number.
128 * Don't use this function from within an interrupt context, like a
129 * bottom half handler. If you need an asynchronous message, or need to send
130 * a message from within interrupt context, use usb_submit_urb()
131 * If a thread in your driver uses this call, make sure your disconnect()
132 * method can wait for it to complete. Since you don't have a handle on
133 * the URB used, you can't cancel the request.
135 int usb_control_msg(struct usb_device
*dev
, unsigned int pipe
, __u8 request
, __u8 requesttype
,
136 __u16 value
, __u16 index
, void *data
, __u16 size
, int timeout
)
138 struct usb_ctrlrequest
*dr
= kmalloc(sizeof(struct usb_ctrlrequest
), GFP_NOIO
);
144 dr
->bRequestType
= requesttype
;
145 dr
->bRequest
= request
;
146 dr
->wValue
= cpu_to_le16p(&value
);
147 dr
->wIndex
= cpu_to_le16p(&index
);
148 dr
->wLength
= cpu_to_le16p(&size
);
150 //dbg("usb_control_msg");
152 ret
= usb_internal_control_msg(dev
, pipe
, dr
, data
, size
, timeout
);
161 * usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion
162 * @usb_dev: pointer to the usb device to send the message to
163 * @pipe: endpoint "pipe" to send the message to
164 * @data: pointer to the data to send
165 * @len: length in bytes of the data to send
166 * @actual_length: pointer to a location to put the actual length transferred in bytes
167 * @timeout: time in msecs to wait for the message to complete before
168 * timing out (if 0 the wait is forever)
169 * Context: !in_interrupt ()
171 * This function sends a simple bulk message to a specified endpoint
172 * and waits for the message to complete, or timeout.
174 * If successful, it returns 0, otherwise a negative error number.
175 * The number of actual bytes transferred will be stored in the
176 * actual_length paramater.
178 * Don't use this function from within an interrupt context, like a
179 * bottom half handler. If you need an asynchronous message, or need to
180 * send a message from within interrupt context, use usb_submit_urb()
181 * If a thread in your driver uses this call, make sure your disconnect()
182 * method can wait for it to complete. Since you don't have a handle on
183 * the URB used, you can't cancel the request.
185 * Because there is no usb_interrupt_msg() and no USBDEVFS_INTERRUPT
186 * ioctl, users are forced to abuse this routine by using it to submit
187 * URBs for interrupt endpoints. We will take the liberty of creating
188 * an interrupt URB (with the default interval) if the target is an
189 * interrupt endpoint.
191 int usb_bulk_msg(struct usb_device
*usb_dev
, unsigned int pipe
,
192 void *data
, int len
, int *actual_length
, int timeout
)
195 struct usb_host_endpoint
*ep
;
197 ep
= (usb_pipein(pipe
) ? usb_dev
->ep_in
: usb_dev
->ep_out
)
198 [usb_pipeendpoint(pipe
)];
202 urb
= usb_alloc_urb(0, GFP_KERNEL
);
206 if ((ep
->desc
.bmAttributes
& USB_ENDPOINT_XFERTYPE_MASK
) ==
207 USB_ENDPOINT_XFER_INT
) {
208 pipe
= (pipe
& ~(3 << 30)) | (PIPE_INTERRUPT
<< 30);
209 usb_fill_int_urb(urb
, usb_dev
, pipe
, data
, len
,
210 usb_api_blocking_completion
, NULL
,
213 usb_fill_bulk_urb(urb
, usb_dev
, pipe
, data
, len
,
214 usb_api_blocking_completion
, NULL
);
216 return usb_start_wait_urb(urb
, timeout
, actual_length
);
219 /*-------------------------------------------------------------------*/
221 static void sg_clean (struct usb_sg_request
*io
)
224 while (io
->entries
--)
225 usb_free_urb (io
->urbs
[io
->entries
]);
229 if (io
->dev
->dev
.dma_mask
!= NULL
)
230 usb_buffer_unmap_sg (io
->dev
, io
->pipe
, io
->sg
, io
->nents
);
234 static void sg_complete (struct urb
*urb
, struct pt_regs
*regs
)
236 struct usb_sg_request
*io
= (struct usb_sg_request
*) urb
->context
;
238 spin_lock (&io
->lock
);
240 /* In 2.5 we require hcds' endpoint queues not to progress after fault
241 * reports, until the completion callback (this!) returns. That lets
242 * device driver code (like this routine) unlink queued urbs first,
243 * if it needs to, since the HC won't work on them at all. So it's
244 * not possible for page N+1 to overwrite page N, and so on.
246 * That's only for "hard" faults; "soft" faults (unlinks) sometimes
247 * complete before the HCD can get requests away from hardware,
248 * though never during cleanup after a hard fault.
251 && (io
->status
!= -ECONNRESET
252 || urb
->status
!= -ECONNRESET
)
253 && urb
->actual_length
) {
254 dev_err (io
->dev
->bus
->controller
,
255 "dev %s ep%d%s scatterlist error %d/%d\n",
257 usb_pipeendpoint (urb
->pipe
),
258 usb_pipein (urb
->pipe
) ? "in" : "out",
259 urb
->status
, io
->status
);
263 if (io
->status
== 0 && urb
->status
&& urb
->status
!= -ECONNRESET
) {
264 int i
, found
, status
;
266 io
->status
= urb
->status
;
268 /* the previous urbs, and this one, completed already.
269 * unlink pending urbs so they won't rx/tx bad data.
270 * careful: unlink can sometimes be synchronous...
272 spin_unlock (&io
->lock
);
273 for (i
= 0, found
= 0; i
< io
->entries
; i
++) {
274 if (!io
->urbs
[i
] || !io
->urbs
[i
]->dev
)
277 status
= usb_unlink_urb (io
->urbs
[i
]);
278 if (status
!= -EINPROGRESS
281 dev_err (&io
->dev
->dev
,
282 "%s, unlink --> %d\n",
283 __FUNCTION__
, status
);
284 } else if (urb
== io
->urbs
[i
])
287 spin_lock (&io
->lock
);
291 /* on the last completion, signal usb_sg_wait() */
292 io
->bytes
+= urb
->actual_length
;
295 complete (&io
->complete
);
297 spin_unlock (&io
->lock
);
302 * usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request
303 * @io: request block being initialized. until usb_sg_wait() returns,
304 * treat this as a pointer to an opaque block of memory,
305 * @dev: the usb device that will send or receive the data
306 * @pipe: endpoint "pipe" used to transfer the data
307 * @period: polling rate for interrupt endpoints, in frames or
308 * (for high speed endpoints) microframes; ignored for bulk
309 * @sg: scatterlist entries
310 * @nents: how many entries in the scatterlist
311 * @length: how many bytes to send from the scatterlist, or zero to
312 * send every byte identified in the list.
313 * @mem_flags: SLAB_* flags affecting memory allocations in this call
315 * Returns zero for success, else a negative errno value. This initializes a
316 * scatter/gather request, allocating resources such as I/O mappings and urb
317 * memory (except maybe memory used by USB controller drivers).
319 * The request must be issued using usb_sg_wait(), which waits for the I/O to
320 * complete (or to be canceled) and then cleans up all resources allocated by
323 * The request may be canceled with usb_sg_cancel(), either before or after
324 * usb_sg_wait() is called.
327 struct usb_sg_request
*io
,
328 struct usb_device
*dev
,
331 struct scatterlist
*sg
,
341 if (!io
|| !dev
|| !sg
342 || usb_pipecontrol (pipe
)
343 || usb_pipeisoc (pipe
)
347 spin_lock_init (&io
->lock
);
353 /* not all host controllers use DMA (like the mainstream pci ones);
354 * they can use PIO (sl811) or be software over another transport.
356 dma
= (dev
->dev
.dma_mask
!= NULL
);
358 io
->entries
= usb_buffer_map_sg (dev
, pipe
, sg
, nents
);
362 /* initialize all the urbs we'll use */
363 if (io
->entries
<= 0)
366 io
->count
= io
->entries
;
367 io
->urbs
= kmalloc (io
->entries
* sizeof *io
->urbs
, mem_flags
);
371 urb_flags
= URB_NO_TRANSFER_DMA_MAP
| URB_NO_INTERRUPT
;
372 if (usb_pipein (pipe
))
373 urb_flags
|= URB_SHORT_NOT_OK
;
375 for (i
= 0; i
< io
->entries
; i
++) {
378 io
->urbs
[i
] = usb_alloc_urb (0, mem_flags
);
384 io
->urbs
[i
]->dev
= NULL
;
385 io
->urbs
[i
]->pipe
= pipe
;
386 io
->urbs
[i
]->interval
= period
;
387 io
->urbs
[i
]->transfer_flags
= urb_flags
;
389 io
->urbs
[i
]->complete
= sg_complete
;
390 io
->urbs
[i
]->context
= io
;
391 io
->urbs
[i
]->status
= -EINPROGRESS
;
392 io
->urbs
[i
]->actual_length
= 0;
395 /* hc may use _only_ transfer_dma */
396 io
->urbs
[i
]->transfer_dma
= sg_dma_address (sg
+ i
);
397 len
= sg_dma_len (sg
+ i
);
399 /* hc may use _only_ transfer_buffer */
400 io
->urbs
[i
]->transfer_buffer
=
401 page_address (sg
[i
].page
) + sg
[i
].offset
;
406 len
= min_t (unsigned, len
, length
);
411 io
->urbs
[i
]->transfer_buffer_length
= len
;
413 io
->urbs
[--i
]->transfer_flags
&= ~URB_NO_INTERRUPT
;
415 /* transaction state */
418 init_completion (&io
->complete
);
428 * usb_sg_wait - synchronously execute scatter/gather request
429 * @io: request block handle, as initialized with usb_sg_init().
430 * some fields become accessible when this call returns.
431 * Context: !in_interrupt ()
433 * This function blocks until the specified I/O operation completes. It
434 * leverages the grouping of the related I/O requests to get good transfer
435 * rates, by queueing the requests. At higher speeds, such queuing can
436 * significantly improve USB throughput.
438 * There are three kinds of completion for this function.
439 * (1) success, where io->status is zero. The number of io->bytes
440 * transferred is as requested.
441 * (2) error, where io->status is a negative errno value. The number
442 * of io->bytes transferred before the error is usually less
443 * than requested, and can be nonzero.
444 * (3) cancellation, a type of error with status -ECONNRESET that
445 * is initiated by usb_sg_cancel().
447 * When this function returns, all memory allocated through usb_sg_init() or
448 * this call will have been freed. The request block parameter may still be
449 * passed to usb_sg_cancel(), or it may be freed. It could also be
450 * reinitialized and then reused.
452 * Data Transfer Rates:
454 * Bulk transfers are valid for full or high speed endpoints.
455 * The best full speed data rate is 19 packets of 64 bytes each
456 * per frame, or 1216 bytes per millisecond.
457 * The best high speed data rate is 13 packets of 512 bytes each
458 * per microframe, or 52 KBytes per millisecond.
460 * The reason to use interrupt transfers through this API would most likely
461 * be to reserve high speed bandwidth, where up to 24 KBytes per millisecond
462 * could be transferred. That capability is less useful for low or full
463 * speed interrupt endpoints, which allow at most one packet per millisecond,
464 * of at most 8 or 64 bytes (respectively).
466 void usb_sg_wait (struct usb_sg_request
*io
)
468 int i
, entries
= io
->entries
;
470 /* queue the urbs. */
471 spin_lock_irq (&io
->lock
);
472 for (i
= 0; i
< entries
&& !io
->status
; i
++) {
475 io
->urbs
[i
]->dev
= io
->dev
;
476 retval
= usb_submit_urb (io
->urbs
[i
], SLAB_ATOMIC
);
478 /* after we submit, let completions or cancelations fire;
479 * we handshake using io->status.
481 spin_unlock_irq (&io
->lock
);
483 /* maybe we retrying will recover */
484 case -ENXIO
: // hc didn't queue this one
487 io
->urbs
[i
]->dev
= NULL
;
493 /* no error? continue immediately.
495 * NOTE: to work better with UHCI (4K I/O buffer may
496 * need 3K of TDs) it may be good to limit how many
497 * URBs are queued at once; N milliseconds?
503 /* fail any uncompleted urbs */
505 io
->urbs
[i
]->dev
= NULL
;
506 io
->urbs
[i
]->status
= retval
;
507 dev_dbg (&io
->dev
->dev
, "%s, submit --> %d\n",
508 __FUNCTION__
, retval
);
511 spin_lock_irq (&io
->lock
);
512 if (retval
&& (io
->status
== 0 || io
->status
== -ECONNRESET
))
515 io
->count
-= entries
- i
;
517 complete (&io
->complete
);
518 spin_unlock_irq (&io
->lock
);
520 /* OK, yes, this could be packaged as non-blocking.
521 * So could the submit loop above ... but it's easier to
522 * solve neither problem than to solve both!
524 wait_for_completion (&io
->complete
);
530 * usb_sg_cancel - stop scatter/gather i/o issued by usb_sg_wait()
531 * @io: request block, initialized with usb_sg_init()
533 * This stops a request after it has been started by usb_sg_wait().
534 * It can also prevents one initialized by usb_sg_init() from starting,
535 * so that call just frees resources allocated to the request.
537 void usb_sg_cancel (struct usb_sg_request
*io
)
541 spin_lock_irqsave (&io
->lock
, flags
);
543 /* shut everything down, if it didn't already */
547 io
->status
= -ECONNRESET
;
548 spin_unlock (&io
->lock
);
549 for (i
= 0; i
< io
->entries
; i
++) {
552 if (!io
->urbs
[i
]->dev
)
554 retval
= usb_unlink_urb (io
->urbs
[i
]);
555 if (retval
!= -EINPROGRESS
&& retval
!= -EBUSY
)
556 dev_warn (&io
->dev
->dev
, "%s, unlink --> %d\n",
557 __FUNCTION__
, retval
);
559 spin_lock (&io
->lock
);
561 spin_unlock_irqrestore (&io
->lock
, flags
);
564 /*-------------------------------------------------------------------*/
567 * usb_get_descriptor - issues a generic GET_DESCRIPTOR request
568 * @dev: the device whose descriptor is being retrieved
569 * @type: the descriptor type (USB_DT_*)
570 * @index: the number of the descriptor
571 * @buf: where to put the descriptor
572 * @size: how big is "buf"?
573 * Context: !in_interrupt ()
575 * Gets a USB descriptor. Convenience functions exist to simplify
576 * getting some types of descriptors. Use
577 * usb_get_string() or usb_string() for USB_DT_STRING.
578 * Device (USB_DT_DEVICE) and configuration descriptors (USB_DT_CONFIG)
579 * are part of the device structure.
580 * In addition to a number of USB-standard descriptors, some
581 * devices also use class-specific or vendor-specific descriptors.
583 * This call is synchronous, and may not be used in an interrupt context.
585 * Returns the number of bytes received on success, or else the status code
586 * returned by the underlying usb_control_msg() call.
588 int usb_get_descriptor(struct usb_device
*dev
, unsigned char type
, unsigned char index
, void *buf
, int size
)
593 memset(buf
,0,size
); // Make sure we parse really received data
595 for (i
= 0; i
< 3; ++i
) {
596 /* retry on length 0 or stall; some devices are flakey */
597 result
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0),
598 USB_REQ_GET_DESCRIPTOR
, USB_DIR_IN
,
599 (type
<< 8) + index
, 0, buf
, size
,
600 USB_CTRL_GET_TIMEOUT
);
601 if (result
== 0 || result
== -EPIPE
)
603 if (result
> 1 && ((u8
*)buf
)[1] != type
) {
613 * usb_get_string - gets a string descriptor
614 * @dev: the device whose string descriptor is being retrieved
615 * @langid: code for language chosen (from string descriptor zero)
616 * @index: the number of the descriptor
617 * @buf: where to put the string
618 * @size: how big is "buf"?
619 * Context: !in_interrupt ()
621 * Retrieves a string, encoded using UTF-16LE (Unicode, 16 bits per character,
622 * in little-endian byte order).
623 * The usb_string() function will often be a convenient way to turn
624 * these strings into kernel-printable form.
626 * Strings may be referenced in device, configuration, interface, or other
627 * descriptors, and could also be used in vendor-specific ways.
629 * This call is synchronous, and may not be used in an interrupt context.
631 * Returns the number of bytes received on success, or else the status code
632 * returned by the underlying usb_control_msg() call.
634 static int usb_get_string(struct usb_device
*dev
, unsigned short langid
,
635 unsigned char index
, void *buf
, int size
)
640 for (i
= 0; i
< 3; ++i
) {
641 /* retry on length 0 or stall; some devices are flakey */
642 result
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0),
643 USB_REQ_GET_DESCRIPTOR
, USB_DIR_IN
,
644 (USB_DT_STRING
<< 8) + index
, langid
, buf
, size
,
645 USB_CTRL_GET_TIMEOUT
);
646 if (!(result
== 0 || result
== -EPIPE
))
652 static void usb_try_string_workarounds(unsigned char *buf
, int *length
)
654 int newlength
, oldlength
= *length
;
656 for (newlength
= 2; newlength
+ 1 < oldlength
; newlength
+= 2)
657 if (!isprint(buf
[newlength
]) || buf
[newlength
+ 1])
666 static int usb_string_sub(struct usb_device
*dev
, unsigned int langid
,
667 unsigned int index
, unsigned char *buf
)
671 /* Try to read the string descriptor by asking for the maximum
672 * possible number of bytes */
673 rc
= usb_get_string(dev
, langid
, index
, buf
, 255);
675 /* If that failed try to read the descriptor length, then
676 * ask for just that many bytes */
678 rc
= usb_get_string(dev
, langid
, index
, buf
, 2);
680 rc
= usb_get_string(dev
, langid
, index
, buf
, buf
[0]);
684 if (!buf
[0] && !buf
[1])
685 usb_try_string_workarounds(buf
, &rc
);
687 /* There might be extra junk at the end of the descriptor */
691 rc
= rc
- (rc
& 1); /* force a multiple of two */
695 rc
= (rc
< 0 ? rc
: -EINVAL
);
701 * usb_string - returns ISO 8859-1 version of a string descriptor
702 * @dev: the device whose string descriptor is being retrieved
703 * @index: the number of the descriptor
704 * @buf: where to put the string
705 * @size: how big is "buf"?
706 * Context: !in_interrupt ()
708 * This converts the UTF-16LE encoded strings returned by devices, from
709 * usb_get_string_descriptor(), to null-terminated ISO-8859-1 encoded ones
710 * that are more usable in most kernel contexts. Note that all characters
711 * in the chosen descriptor that can't be encoded using ISO-8859-1
712 * are converted to the question mark ("?") character, and this function
713 * chooses strings in the first language supported by the device.
715 * The ASCII (or, redundantly, "US-ASCII") character set is the seven-bit
716 * subset of ISO 8859-1. ISO-8859-1 is the eight-bit subset of Unicode,
717 * and is appropriate for use many uses of English and several other
718 * Western European languages. (But it doesn't include the "Euro" symbol.)
720 * This call is synchronous, and may not be used in an interrupt context.
722 * Returns length of the string (>= 0) or usb_control_msg status (< 0).
724 int usb_string(struct usb_device
*dev
, int index
, char *buf
, size_t size
)
730 if (dev
->state
== USB_STATE_SUSPENDED
)
731 return -EHOSTUNREACH
;
732 if (size
<= 0 || !buf
|| !index
)
735 tbuf
= kmalloc(256, GFP_KERNEL
);
739 /* get langid for strings if it's not yet known */
740 if (!dev
->have_langid
) {
741 err
= usb_string_sub(dev
, 0, 0, tbuf
);
744 "string descriptor 0 read error: %d\n",
747 } else if (err
< 4) {
748 dev_err (&dev
->dev
, "string descriptor 0 too short\n");
752 dev
->have_langid
= -1;
753 dev
->string_langid
= tbuf
[2] | (tbuf
[3]<< 8);
754 /* always use the first langid listed */
755 dev_dbg (&dev
->dev
, "default language 0x%04x\n",
760 err
= usb_string_sub(dev
, dev
->string_langid
, index
, tbuf
);
764 size
--; /* leave room for trailing NULL char in output buffer */
765 for (idx
= 0, u
= 2; u
< err
; u
+= 2) {
768 if (tbuf
[u
+1]) /* high byte */
769 buf
[idx
++] = '?'; /* non ISO-8859-1 character */
771 buf
[idx
++] = tbuf
[u
];
776 if (tbuf
[1] != USB_DT_STRING
)
777 dev_dbg(&dev
->dev
, "wrong descriptor type %02x for string %d (\"%s\")\n", tbuf
[1], index
, buf
);
785 * usb_cache_string - read a string descriptor and cache it for later use
786 * @udev: the device whose string descriptor is being read
787 * @index: the descriptor index
789 * Returns a pointer to a kmalloc'ed buffer containing the descriptor string,
790 * or NULL if the index is 0 or the string could not be read.
792 char *usb_cache_string(struct usb_device
*udev
, int index
)
795 char *smallbuf
= NULL
;
798 if (index
> 0 && (buf
= kmalloc(256, GFP_KERNEL
)) != NULL
) {
799 if ((len
= usb_string(udev
, index
, buf
, 256)) > 0) {
800 if ((smallbuf
= kmalloc(++len
, GFP_KERNEL
)) == NULL
)
802 memcpy(smallbuf
, buf
, len
);
810 * usb_get_device_descriptor - (re)reads the device descriptor (usbcore)
811 * @dev: the device whose device descriptor is being updated
812 * @size: how much of the descriptor to read
813 * Context: !in_interrupt ()
815 * Updates the copy of the device descriptor stored in the device structure,
816 * which dedicates space for this purpose. Note that several fields are
817 * converted to the host CPU's byte order: the USB version (bcdUSB), and
818 * vendors product and version fields (idVendor, idProduct, and bcdDevice).
819 * That lets device drivers compare against non-byteswapped constants.
821 * Not exported, only for use by the core. If drivers really want to read
822 * the device descriptor directly, they can call usb_get_descriptor() with
823 * type = USB_DT_DEVICE and index = 0.
825 * This call is synchronous, and may not be used in an interrupt context.
827 * Returns the number of bytes received on success, or else the status code
828 * returned by the underlying usb_control_msg() call.
830 int usb_get_device_descriptor(struct usb_device
*dev
, unsigned int size
)
832 struct usb_device_descriptor
*desc
;
835 if (size
> sizeof(*desc
))
837 desc
= kmalloc(sizeof(*desc
), GFP_NOIO
);
841 ret
= usb_get_descriptor(dev
, USB_DT_DEVICE
, 0, desc
, size
);
843 memcpy(&dev
->descriptor
, desc
, size
);
849 * usb_get_status - issues a GET_STATUS call
850 * @dev: the device whose status is being checked
851 * @type: USB_RECIP_*; for device, interface, or endpoint
852 * @target: zero (for device), else interface or endpoint number
853 * @data: pointer to two bytes of bitmap data
854 * Context: !in_interrupt ()
856 * Returns device, interface, or endpoint status. Normally only of
857 * interest to see if the device is self powered, or has enabled the
858 * remote wakeup facility; or whether a bulk or interrupt endpoint
859 * is halted ("stalled").
861 * Bits in these status bitmaps are set using the SET_FEATURE request,
862 * and cleared using the CLEAR_FEATURE request. The usb_clear_halt()
863 * function should be used to clear halt ("stall") status.
865 * This call is synchronous, and may not be used in an interrupt context.
867 * Returns the number of bytes received on success, or else the status code
868 * returned by the underlying usb_control_msg() call.
870 int usb_get_status(struct usb_device
*dev
, int type
, int target
, void *data
)
873 u16
*status
= kmalloc(sizeof(*status
), GFP_KERNEL
);
878 ret
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0),
879 USB_REQ_GET_STATUS
, USB_DIR_IN
| type
, 0, target
, status
,
880 sizeof(*status
), USB_CTRL_GET_TIMEOUT
);
882 *(u16
*)data
= *status
;
888 * usb_clear_halt - tells device to clear endpoint halt/stall condition
889 * @dev: device whose endpoint is halted
890 * @pipe: endpoint "pipe" being cleared
891 * Context: !in_interrupt ()
893 * This is used to clear halt conditions for bulk and interrupt endpoints,
894 * as reported by URB completion status. Endpoints that are halted are
895 * sometimes referred to as being "stalled". Such endpoints are unable
896 * to transmit or receive data until the halt status is cleared. Any URBs
897 * queued for such an endpoint should normally be unlinked by the driver
898 * before clearing the halt condition, as described in sections 5.7.5
899 * and 5.8.5 of the USB 2.0 spec.
901 * Note that control and isochronous endpoints don't halt, although control
902 * endpoints report "protocol stall" (for unsupported requests) using the
903 * same status code used to report a true stall.
905 * This call is synchronous, and may not be used in an interrupt context.
907 * Returns zero on success, or else the status code returned by the
908 * underlying usb_control_msg() call.
910 int usb_clear_halt(struct usb_device
*dev
, int pipe
)
913 int endp
= usb_pipeendpoint(pipe
);
915 if (usb_pipein (pipe
))
918 /* we don't care if it wasn't halted first. in fact some devices
919 * (like some ibmcam model 1 units) seem to expect hosts to make
920 * this request for iso endpoints, which can't halt!
922 result
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
923 USB_REQ_CLEAR_FEATURE
, USB_RECIP_ENDPOINT
,
924 USB_ENDPOINT_HALT
, endp
, NULL
, 0,
925 USB_CTRL_SET_TIMEOUT
);
927 /* don't un-halt or force to DATA0 except on success */
931 /* NOTE: seems like Microsoft and Apple don't bother verifying
932 * the clear "took", so some devices could lock up if you check...
933 * such as the Hagiwara FlashGate DUAL. So we won't bother.
935 * NOTE: make sure the logic here doesn't diverge much from
936 * the copy in usb-storage, for as long as we need two copies.
939 /* toggle was reset by the clear */
940 usb_settoggle(dev
, usb_pipeendpoint(pipe
), usb_pipeout(pipe
), 0);
946 * usb_disable_endpoint -- Disable an endpoint by address
947 * @dev: the device whose endpoint is being disabled
948 * @epaddr: the endpoint's address. Endpoint number for output,
949 * endpoint number + USB_DIR_IN for input
951 * Deallocates hcd/hardware state for this endpoint ... and nukes all
954 * If the HCD hasn't registered a disable() function, this sets the
955 * endpoint's maxpacket size to 0 to prevent further submissions.
957 void usb_disable_endpoint(struct usb_device
*dev
, unsigned int epaddr
)
959 unsigned int epnum
= epaddr
& USB_ENDPOINT_NUMBER_MASK
;
960 struct usb_host_endpoint
*ep
;
965 if (usb_endpoint_out(epaddr
)) {
966 ep
= dev
->ep_out
[epnum
];
967 dev
->ep_out
[epnum
] = NULL
;
969 ep
= dev
->ep_in
[epnum
];
970 dev
->ep_in
[epnum
] = NULL
;
972 if (ep
&& dev
->bus
&& dev
->bus
->op
&& dev
->bus
->op
->disable
)
973 dev
->bus
->op
->disable(dev
, ep
);
977 * usb_disable_interface -- Disable all endpoints for an interface
978 * @dev: the device whose interface is being disabled
979 * @intf: pointer to the interface descriptor
981 * Disables all the endpoints for the interface's current altsetting.
983 void usb_disable_interface(struct usb_device
*dev
, struct usb_interface
*intf
)
985 struct usb_host_interface
*alt
= intf
->cur_altsetting
;
988 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; ++i
) {
989 usb_disable_endpoint(dev
,
990 alt
->endpoint
[i
].desc
.bEndpointAddress
);
995 * usb_disable_device - Disable all the endpoints for a USB device
996 * @dev: the device whose endpoints are being disabled
997 * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
999 * Disables all the device's endpoints, potentially including endpoint 0.
1000 * Deallocates hcd/hardware state for the endpoints (nuking all or most
1001 * pending urbs) and usbcore state for the interfaces, so that usbcore
1002 * must usb_set_configuration() before any interfaces could be used.
1004 void usb_disable_device(struct usb_device
*dev
, int skip_ep0
)
1008 dev_dbg(&dev
->dev
, "%s nuking %s URBs\n", __FUNCTION__
,
1009 skip_ep0
? "non-ep0" : "all");
1010 for (i
= skip_ep0
; i
< 16; ++i
) {
1011 usb_disable_endpoint(dev
, i
);
1012 usb_disable_endpoint(dev
, i
+ USB_DIR_IN
);
1014 dev
->toggle
[0] = dev
->toggle
[1] = 0;
1016 /* getting rid of interfaces will disconnect
1017 * any drivers bound to them (a key side effect)
1019 if (dev
->actconfig
) {
1020 for (i
= 0; i
< dev
->actconfig
->desc
.bNumInterfaces
; i
++) {
1021 struct usb_interface
*interface
;
1023 /* remove this interface if it has been registered */
1024 interface
= dev
->actconfig
->interface
[i
];
1025 if (!device_is_registered(&interface
->dev
))
1027 dev_dbg (&dev
->dev
, "unregistering interface %s\n",
1028 interface
->dev
.bus_id
);
1029 usb_remove_sysfs_intf_files(interface
);
1030 device_del (&interface
->dev
);
1033 /* Now that the interfaces are unbound, nobody should
1034 * try to access them.
1036 for (i
= 0; i
< dev
->actconfig
->desc
.bNumInterfaces
; i
++) {
1037 put_device (&dev
->actconfig
->interface
[i
]->dev
);
1038 dev
->actconfig
->interface
[i
] = NULL
;
1040 dev
->actconfig
= NULL
;
1041 if (dev
->state
== USB_STATE_CONFIGURED
)
1042 usb_set_device_state(dev
, USB_STATE_ADDRESS
);
1048 * usb_enable_endpoint - Enable an endpoint for USB communications
1049 * @dev: the device whose interface is being enabled
1052 * Resets the endpoint toggle, and sets dev->ep_{in,out} pointers.
1053 * For control endpoints, both the input and output sides are handled.
1056 usb_enable_endpoint(struct usb_device
*dev
, struct usb_host_endpoint
*ep
)
1058 unsigned int epaddr
= ep
->desc
.bEndpointAddress
;
1059 unsigned int epnum
= epaddr
& USB_ENDPOINT_NUMBER_MASK
;
1062 is_control
= ((ep
->desc
.bmAttributes
& USB_ENDPOINT_XFERTYPE_MASK
)
1063 == USB_ENDPOINT_XFER_CONTROL
);
1064 if (usb_endpoint_out(epaddr
) || is_control
) {
1065 usb_settoggle(dev
, epnum
, 1, 0);
1066 dev
->ep_out
[epnum
] = ep
;
1068 if (!usb_endpoint_out(epaddr
) || is_control
) {
1069 usb_settoggle(dev
, epnum
, 0, 0);
1070 dev
->ep_in
[epnum
] = ep
;
1075 * usb_enable_interface - Enable all the endpoints for an interface
1076 * @dev: the device whose interface is being enabled
1077 * @intf: pointer to the interface descriptor
1079 * Enables all the endpoints for the interface's current altsetting.
1081 static void usb_enable_interface(struct usb_device
*dev
,
1082 struct usb_interface
*intf
)
1084 struct usb_host_interface
*alt
= intf
->cur_altsetting
;
1087 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; ++i
)
1088 usb_enable_endpoint(dev
, &alt
->endpoint
[i
]);
1092 * usb_set_interface - Makes a particular alternate setting be current
1093 * @dev: the device whose interface is being updated
1094 * @interface: the interface being updated
1095 * @alternate: the setting being chosen.
1096 * Context: !in_interrupt ()
1098 * This is used to enable data transfers on interfaces that may not
1099 * be enabled by default. Not all devices support such configurability.
1100 * Only the driver bound to an interface may change its setting.
1102 * Within any given configuration, each interface may have several
1103 * alternative settings. These are often used to control levels of
1104 * bandwidth consumption. For example, the default setting for a high
1105 * speed interrupt endpoint may not send more than 64 bytes per microframe,
1106 * while interrupt transfers of up to 3KBytes per microframe are legal.
1107 * Also, isochronous endpoints may never be part of an
1108 * interface's default setting. To access such bandwidth, alternate
1109 * interface settings must be made current.
1111 * Note that in the Linux USB subsystem, bandwidth associated with
1112 * an endpoint in a given alternate setting is not reserved until an URB
1113 * is submitted that needs that bandwidth. Some other operating systems
1114 * allocate bandwidth early, when a configuration is chosen.
1116 * This call is synchronous, and may not be used in an interrupt context.
1117 * Also, drivers must not change altsettings while urbs are scheduled for
1118 * endpoints in that interface; all such urbs must first be completed
1119 * (perhaps forced by unlinking).
1121 * Returns zero on success, or else the status code returned by the
1122 * underlying usb_control_msg() call.
1124 int usb_set_interface(struct usb_device
*dev
, int interface
, int alternate
)
1126 struct usb_interface
*iface
;
1127 struct usb_host_interface
*alt
;
1131 if (dev
->state
== USB_STATE_SUSPENDED
)
1132 return -EHOSTUNREACH
;
1134 iface
= usb_ifnum_to_if(dev
, interface
);
1136 dev_dbg(&dev
->dev
, "selecting invalid interface %d\n",
1141 alt
= usb_altnum_to_altsetting(iface
, alternate
);
1143 warn("selecting invalid altsetting %d", alternate
);
1147 ret
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
1148 USB_REQ_SET_INTERFACE
, USB_RECIP_INTERFACE
,
1149 alternate
, interface
, NULL
, 0, 5000);
1151 /* 9.4.10 says devices don't need this and are free to STALL the
1152 * request if the interface only has one alternate setting.
1154 if (ret
== -EPIPE
&& iface
->num_altsetting
== 1) {
1156 "manual set_interface for iface %d, alt %d\n",
1157 interface
, alternate
);
1162 /* FIXME drivers shouldn't need to replicate/bugfix the logic here
1163 * when they implement async or easily-killable versions of this or
1164 * other "should-be-internal" functions (like clear_halt).
1165 * should hcd+usbcore postprocess control requests?
1168 /* prevent submissions using previous endpoint settings */
1169 if (device_is_registered(&iface
->dev
))
1170 usb_remove_sysfs_intf_files(iface
);
1171 usb_disable_interface(dev
, iface
);
1173 iface
->cur_altsetting
= alt
;
1175 /* If the interface only has one altsetting and the device didn't
1176 * accept the request, we attempt to carry out the equivalent action
1177 * by manually clearing the HALT feature for each endpoint in the
1183 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; i
++) {
1184 unsigned int epaddr
=
1185 alt
->endpoint
[i
].desc
.bEndpointAddress
;
1187 __create_pipe(dev
, USB_ENDPOINT_NUMBER_MASK
& epaddr
)
1188 | (usb_endpoint_out(epaddr
) ? USB_DIR_OUT
: USB_DIR_IN
);
1190 usb_clear_halt(dev
, pipe
);
1194 /* 9.1.1.5: reset toggles for all endpoints in the new altsetting
1197 * Despite EP0 is always present in all interfaces/AS, the list of
1198 * endpoints from the descriptor does not contain EP0. Due to its
1199 * omnipresence one might expect EP0 being considered "affected" by
1200 * any SetInterface request and hence assume toggles need to be reset.
1201 * However, EP0 toggles are re-synced for every individual transfer
1202 * during the SETUP stage - hence EP0 toggles are "don't care" here.
1203 * (Likewise, EP0 never "halts" on well designed devices.)
1205 usb_enable_interface(dev
, iface
);
1206 if (device_is_registered(&iface
->dev
))
1207 usb_create_sysfs_intf_files(iface
);
1213 * usb_reset_configuration - lightweight device reset
1214 * @dev: the device whose configuration is being reset
1216 * This issues a standard SET_CONFIGURATION request to the device using
1217 * the current configuration. The effect is to reset most USB-related
1218 * state in the device, including interface altsettings (reset to zero),
1219 * endpoint halts (cleared), and data toggle (only for bulk and interrupt
1220 * endpoints). Other usbcore state is unchanged, including bindings of
1221 * usb device drivers to interfaces.
1223 * Because this affects multiple interfaces, avoid using this with composite
1224 * (multi-interface) devices. Instead, the driver for each interface may
1225 * use usb_set_interface() on the interfaces it claims. Be careful though;
1226 * some devices don't support the SET_INTERFACE request, and others won't
1227 * reset all the interface state (notably data toggles). Resetting the whole
1228 * configuration would affect other drivers' interfaces.
1230 * The caller must own the device lock.
1232 * Returns zero on success, else a negative error code.
1234 int usb_reset_configuration(struct usb_device
*dev
)
1237 struct usb_host_config
*config
;
1239 if (dev
->state
== USB_STATE_SUSPENDED
)
1240 return -EHOSTUNREACH
;
1242 /* caller must have locked the device and must own
1243 * the usb bus readlock (so driver bindings are stable);
1244 * calls during probe() are fine
1247 for (i
= 1; i
< 16; ++i
) {
1248 usb_disable_endpoint(dev
, i
);
1249 usb_disable_endpoint(dev
, i
+ USB_DIR_IN
);
1252 config
= dev
->actconfig
;
1253 retval
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
1254 USB_REQ_SET_CONFIGURATION
, 0,
1255 config
->desc
.bConfigurationValue
, 0,
1256 NULL
, 0, USB_CTRL_SET_TIMEOUT
);
1260 dev
->toggle
[0] = dev
->toggle
[1] = 0;
1262 /* re-init hc/hcd interface/endpoint state */
1263 for (i
= 0; i
< config
->desc
.bNumInterfaces
; i
++) {
1264 struct usb_interface
*intf
= config
->interface
[i
];
1265 struct usb_host_interface
*alt
;
1267 if (device_is_registered(&intf
->dev
))
1268 usb_remove_sysfs_intf_files(intf
);
1269 alt
= usb_altnum_to_altsetting(intf
, 0);
1271 /* No altsetting 0? We'll assume the first altsetting.
1272 * We could use a GetInterface call, but if a device is
1273 * so non-compliant that it doesn't have altsetting 0
1274 * then I wouldn't trust its reply anyway.
1277 alt
= &intf
->altsetting
[0];
1279 intf
->cur_altsetting
= alt
;
1280 usb_enable_interface(dev
, intf
);
1281 if (device_is_registered(&intf
->dev
))
1282 usb_create_sysfs_intf_files(intf
);
1287 static void release_interface(struct device
*dev
)
1289 struct usb_interface
*intf
= to_usb_interface(dev
);
1290 struct usb_interface_cache
*intfc
=
1291 altsetting_to_usb_interface_cache(intf
->altsetting
);
1293 kref_put(&intfc
->ref
, usb_release_interface_cache
);
1298 * usb_set_configuration - Makes a particular device setting be current
1299 * @dev: the device whose configuration is being updated
1300 * @configuration: the configuration being chosen.
1301 * Context: !in_interrupt(), caller owns the device lock
1303 * This is used to enable non-default device modes. Not all devices
1304 * use this kind of configurability; many devices only have one
1307 * USB device configurations may affect Linux interoperability,
1308 * power consumption and the functionality available. For example,
1309 * the default configuration is limited to using 100mA of bus power,
1310 * so that when certain device functionality requires more power,
1311 * and the device is bus powered, that functionality should be in some
1312 * non-default device configuration. Other device modes may also be
1313 * reflected as configuration options, such as whether two ISDN
1314 * channels are available independently; and choosing between open
1315 * standard device protocols (like CDC) or proprietary ones.
1317 * Note that USB has an additional level of device configurability,
1318 * associated with interfaces. That configurability is accessed using
1319 * usb_set_interface().
1321 * This call is synchronous. The calling context must be able to sleep,
1322 * must own the device lock, and must not hold the driver model's USB
1323 * bus rwsem; usb device driver probe() methods cannot use this routine.
1325 * Returns zero on success, or else the status code returned by the
1326 * underlying call that failed. On successful completion, each interface
1327 * in the original device configuration has been destroyed, and each one
1328 * in the new configuration has been probed by all relevant usb device
1329 * drivers currently known to the kernel.
1331 int usb_set_configuration(struct usb_device
*dev
, int configuration
)
1334 struct usb_host_config
*cp
= NULL
;
1335 struct usb_interface
**new_interfaces
= NULL
;
1338 for (i
= 0; i
< dev
->descriptor
.bNumConfigurations
; i
++) {
1339 if (dev
->config
[i
].desc
.bConfigurationValue
== configuration
) {
1340 cp
= &dev
->config
[i
];
1344 if ((!cp
&& configuration
!= 0))
1347 /* The USB spec says configuration 0 means unconfigured.
1348 * But if a device includes a configuration numbered 0,
1349 * we will accept it as a correctly configured state.
1351 if (cp
&& configuration
== 0)
1352 dev_warn(&dev
->dev
, "config 0 descriptor??\n");
1354 if (dev
->state
== USB_STATE_SUSPENDED
)
1355 return -EHOSTUNREACH
;
1357 /* Allocate memory for new interfaces before doing anything else,
1358 * so that if we run out then nothing will have changed. */
1361 nintf
= cp
->desc
.bNumInterfaces
;
1362 new_interfaces
= kmalloc(nintf
* sizeof(*new_interfaces
),
1364 if (!new_interfaces
) {
1365 dev_err(&dev
->dev
, "Out of memory");
1369 for (; n
< nintf
; ++n
) {
1370 new_interfaces
[n
] = kzalloc(
1371 sizeof(struct usb_interface
),
1373 if (!new_interfaces
[n
]) {
1374 dev_err(&dev
->dev
, "Out of memory");
1378 kfree(new_interfaces
[n
]);
1379 kfree(new_interfaces
);
1385 /* if it's already configured, clear out old state first.
1386 * getting rid of old interfaces means unbinding their drivers.
1388 if (dev
->state
!= USB_STATE_ADDRESS
)
1389 usb_disable_device (dev
, 1); // Skip ep0
1392 i
= dev
->bus_mA
- cp
->desc
.bMaxPower
* 2;
1394 dev_warn(&dev
->dev
, "new config #%d exceeds power "
1399 if ((ret
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
1400 USB_REQ_SET_CONFIGURATION
, 0, configuration
, 0,
1401 NULL
, 0, USB_CTRL_SET_TIMEOUT
)) < 0)
1402 goto free_interfaces
;
1404 dev
->actconfig
= cp
;
1406 usb_set_device_state(dev
, USB_STATE_ADDRESS
);
1408 usb_set_device_state(dev
, USB_STATE_CONFIGURED
);
1410 /* Initialize the new interface structures and the
1411 * hc/hcd/usbcore interface/endpoint state.
1413 for (i
= 0; i
< nintf
; ++i
) {
1414 struct usb_interface_cache
*intfc
;
1415 struct usb_interface
*intf
;
1416 struct usb_host_interface
*alt
;
1418 cp
->interface
[i
] = intf
= new_interfaces
[i
];
1419 intfc
= cp
->intf_cache
[i
];
1420 intf
->altsetting
= intfc
->altsetting
;
1421 intf
->num_altsetting
= intfc
->num_altsetting
;
1422 kref_get(&intfc
->ref
);
1424 alt
= usb_altnum_to_altsetting(intf
, 0);
1426 /* No altsetting 0? We'll assume the first altsetting.
1427 * We could use a GetInterface call, but if a device is
1428 * so non-compliant that it doesn't have altsetting 0
1429 * then I wouldn't trust its reply anyway.
1432 alt
= &intf
->altsetting
[0];
1434 intf
->cur_altsetting
= alt
;
1435 usb_enable_interface(dev
, intf
);
1436 intf
->dev
.parent
= &dev
->dev
;
1437 intf
->dev
.driver
= NULL
;
1438 intf
->dev
.bus
= &usb_bus_type
;
1439 intf
->dev
.dma_mask
= dev
->dev
.dma_mask
;
1440 intf
->dev
.release
= release_interface
;
1441 device_initialize (&intf
->dev
);
1442 mark_quiesced(intf
);
1443 sprintf (&intf
->dev
.bus_id
[0], "%d-%s:%d.%d",
1444 dev
->bus
->busnum
, dev
->devpath
,
1446 alt
->desc
.bInterfaceNumber
);
1448 kfree(new_interfaces
);
1450 if (cp
->string
== NULL
)
1451 cp
->string
= usb_cache_string(dev
,
1452 cp
->desc
.iConfiguration
);
1454 /* Now that all the interfaces are set up, register them
1455 * to trigger binding of drivers to interfaces. probe()
1456 * routines may install different altsettings and may
1457 * claim() any interfaces not yet bound. Many class drivers
1458 * need that: CDC, audio, video, etc.
1460 for (i
= 0; i
< nintf
; ++i
) {
1461 struct usb_interface
*intf
= cp
->interface
[i
];
1464 "adding %s (config #%d, interface %d)\n",
1465 intf
->dev
.bus_id
, configuration
,
1466 intf
->cur_altsetting
->desc
.bInterfaceNumber
);
1467 ret
= device_add (&intf
->dev
);
1470 "device_add(%s) --> %d\n",
1475 usb_create_sysfs_intf_files (intf
);
1482 // synchronous request completion model
1483 EXPORT_SYMBOL(usb_control_msg
);
1484 EXPORT_SYMBOL(usb_bulk_msg
);
1486 EXPORT_SYMBOL(usb_sg_init
);
1487 EXPORT_SYMBOL(usb_sg_cancel
);
1488 EXPORT_SYMBOL(usb_sg_wait
);
1490 // synchronous control message convenience routines
1491 EXPORT_SYMBOL(usb_get_descriptor
);
1492 EXPORT_SYMBOL(usb_get_status
);
1493 EXPORT_SYMBOL(usb_string
);
1495 // synchronous calls that also maintain usbcore state
1496 EXPORT_SYMBOL(usb_clear_halt
);
1497 EXPORT_SYMBOL(usb_reset_configuration
);
1498 EXPORT_SYMBOL(usb_set_interface
);