2 * message.c - synchronous message handling
5 #include <linux/pci.h> /* for scatterlist macros */
7 #include <linux/module.h>
8 #include <linux/slab.h>
9 #include <linux/init.h>
11 #include <linux/timer.h>
12 #include <linux/ctype.h>
13 #include <linux/device.h>
14 #include <linux/scatterlist.h>
15 #include <linux/usb/quirks.h>
16 #include <asm/byteorder.h>
18 #include "hcd.h" /* for usbcore internals */
21 static void cancel_async_set_config(struct usb_device
*udev
);
24 struct completion done
;
28 static void usb_api_blocking_completion(struct urb
*urb
)
30 struct api_context
*ctx
= urb
->context
;
32 ctx
->status
= urb
->status
;
38 * Starts urb and waits for completion or timeout. Note that this call
39 * is NOT interruptible. Many device driver i/o requests should be
40 * interruptible and therefore these drivers should implement their
41 * own interruptible routines.
43 static int usb_start_wait_urb(struct urb
*urb
, int timeout
, int *actual_length
)
45 struct api_context ctx
;
49 init_completion(&ctx
.done
);
51 urb
->actual_length
= 0;
52 retval
= usb_submit_urb(urb
, GFP_NOIO
);
56 expire
= timeout
? msecs_to_jiffies(timeout
) : MAX_SCHEDULE_TIMEOUT
;
57 if (!wait_for_completion_timeout(&ctx
.done
, expire
)) {
59 retval
= (ctx
.status
== -ENOENT
? -ETIMEDOUT
: ctx
.status
);
61 dev_dbg(&urb
->dev
->dev
,
62 "%s timed out on ep%d%s len=%d/%d\n",
64 usb_endpoint_num(&urb
->ep
->desc
),
65 usb_urb_dir_in(urb
) ? "in" : "out",
67 urb
->transfer_buffer_length
);
72 *actual_length
= urb
->actual_length
;
78 /*-------------------------------------------------------------------*/
79 /* returns status (negative) or length (positive) */
80 static int usb_internal_control_msg(struct usb_device
*usb_dev
,
82 struct usb_ctrlrequest
*cmd
,
83 void *data
, int len
, int timeout
)
89 urb
= usb_alloc_urb(0, GFP_NOIO
);
93 usb_fill_control_urb(urb
, usb_dev
, pipe
, (unsigned char *)cmd
, data
,
94 len
, usb_api_blocking_completion
, NULL
);
96 retv
= usb_start_wait_urb(urb
, timeout
, &length
);
104 * usb_control_msg - Builds a control urb, sends it off and waits for completion
105 * @dev: pointer to the usb device to send the message to
106 * @pipe: endpoint "pipe" to send the message to
107 * @request: USB message request value
108 * @requesttype: USB message request type value
109 * @value: USB message value
110 * @index: USB message index value
111 * @data: pointer to the data to send
112 * @size: length in bytes of the data to send
113 * @timeout: time in msecs to wait for the message to complete before timing
114 * out (if 0 the wait is forever)
116 * Context: !in_interrupt ()
118 * This function sends a simple control message to a specified endpoint and
119 * waits for the message to complete, or timeout.
121 * If successful, it returns the number of bytes transferred, otherwise a
122 * negative error number.
124 * Don't use this function from within an interrupt context, like a bottom half
125 * handler. If you need an asynchronous message, or need to send a message
126 * from within interrupt context, use usb_submit_urb().
127 * If a thread in your driver uses this call, make sure your disconnect()
128 * method can wait for it to complete. Since you don't have a handle on the
129 * URB used, you can't cancel the request.
131 int usb_control_msg(struct usb_device
*dev
, unsigned int pipe
, __u8 request
,
132 __u8 requesttype
, __u16 value
, __u16 index
, void *data
,
133 __u16 size
, int timeout
)
135 struct usb_ctrlrequest
*dr
;
138 dr
= kmalloc(sizeof(struct usb_ctrlrequest
), GFP_NOIO
);
142 dr
->bRequestType
= requesttype
;
143 dr
->bRequest
= request
;
144 dr
->wValue
= cpu_to_le16(value
);
145 dr
->wIndex
= cpu_to_le16(index
);
146 dr
->wLength
= cpu_to_le16(size
);
148 /* dbg("usb_control_msg"); */
150 ret
= usb_internal_control_msg(dev
, pipe
, dr
, data
, size
, timeout
);
156 EXPORT_SYMBOL_GPL(usb_control_msg
);
159 * usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for completion
160 * @usb_dev: pointer to the usb device to send the message to
161 * @pipe: endpoint "pipe" to send the message to
162 * @data: pointer to the data to send
163 * @len: length in bytes of the data to send
164 * @actual_length: pointer to a location to put the actual length transferred
166 * @timeout: time in msecs to wait for the message to complete before
167 * timing out (if 0 the wait is forever)
169 * Context: !in_interrupt ()
171 * This function sends a simple interrupt message to a specified endpoint and
172 * waits for the message to complete, or timeout.
174 * If successful, it returns 0, otherwise a negative error number. The number
175 * of actual bytes transferred will be stored in the actual_length paramater.
177 * Don't use this function from within an interrupt context, like a bottom half
178 * handler. If you need an asynchronous message, or need to send a message
179 * from within interrupt context, use usb_submit_urb() If a thread in your
180 * driver uses this call, make sure your disconnect() method can wait for it to
181 * complete. Since you don't have a handle on the URB used, you can't cancel
184 int usb_interrupt_msg(struct usb_device
*usb_dev
, unsigned int pipe
,
185 void *data
, int len
, int *actual_length
, int timeout
)
187 return usb_bulk_msg(usb_dev
, pipe
, data
, len
, actual_length
, timeout
);
189 EXPORT_SYMBOL_GPL(usb_interrupt_msg
);
192 * usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion
193 * @usb_dev: pointer to the usb device to send the message to
194 * @pipe: endpoint "pipe" to send the message to
195 * @data: pointer to the data to send
196 * @len: length in bytes of the data to send
197 * @actual_length: pointer to a location to put the actual length transferred
199 * @timeout: time in msecs to wait for the message to complete before
200 * timing out (if 0 the wait is forever)
202 * Context: !in_interrupt ()
204 * This function sends a simple bulk message to a specified endpoint
205 * and waits for the message to complete, or timeout.
207 * If successful, it returns 0, otherwise a negative error number. The number
208 * of actual bytes transferred will be stored in the actual_length paramater.
210 * Don't use this function from within an interrupt context, like a bottom half
211 * handler. If you need an asynchronous message, or need to send a message
212 * from within interrupt context, use usb_submit_urb() If a thread in your
213 * driver uses this call, make sure your disconnect() method can wait for it to
214 * complete. Since you don't have a handle on the URB used, you can't cancel
217 * Because there is no usb_interrupt_msg() and no USBDEVFS_INTERRUPT ioctl,
218 * users are forced to abuse this routine by using it to submit URBs for
219 * interrupt endpoints. We will take the liberty of creating an interrupt URB
220 * (with the default interval) if the target is an interrupt endpoint.
222 int usb_bulk_msg(struct usb_device
*usb_dev
, unsigned int pipe
,
223 void *data
, int len
, int *actual_length
, int timeout
)
226 struct usb_host_endpoint
*ep
;
228 ep
= (usb_pipein(pipe
) ? usb_dev
->ep_in
: usb_dev
->ep_out
)
229 [usb_pipeendpoint(pipe
)];
233 urb
= usb_alloc_urb(0, GFP_KERNEL
);
237 if ((ep
->desc
.bmAttributes
& USB_ENDPOINT_XFERTYPE_MASK
) ==
238 USB_ENDPOINT_XFER_INT
) {
239 pipe
= (pipe
& ~(3 << 30)) | (PIPE_INTERRUPT
<< 30);
240 usb_fill_int_urb(urb
, usb_dev
, pipe
, data
, len
,
241 usb_api_blocking_completion
, NULL
,
244 usb_fill_bulk_urb(urb
, usb_dev
, pipe
, data
, len
,
245 usb_api_blocking_completion
, NULL
);
247 return usb_start_wait_urb(urb
, timeout
, actual_length
);
249 EXPORT_SYMBOL_GPL(usb_bulk_msg
);
251 /*-------------------------------------------------------------------*/
253 static void sg_clean(struct usb_sg_request
*io
)
256 while (io
->entries
--)
257 usb_free_urb(io
->urbs
[io
->entries
]);
261 if (io
->dev
->dev
.dma_mask
!= NULL
)
262 usb_buffer_unmap_sg(io
->dev
, usb_pipein(io
->pipe
),
267 static void sg_complete(struct urb
*urb
)
269 struct usb_sg_request
*io
= urb
->context
;
270 int status
= urb
->status
;
272 spin_lock(&io
->lock
);
274 /* In 2.5 we require hcds' endpoint queues not to progress after fault
275 * reports, until the completion callback (this!) returns. That lets
276 * device driver code (like this routine) unlink queued urbs first,
277 * if it needs to, since the HC won't work on them at all. So it's
278 * not possible for page N+1 to overwrite page N, and so on.
280 * That's only for "hard" faults; "soft" faults (unlinks) sometimes
281 * complete before the HCD can get requests away from hardware,
282 * though never during cleanup after a hard fault.
285 && (io
->status
!= -ECONNRESET
286 || status
!= -ECONNRESET
)
287 && urb
->actual_length
) {
288 dev_err(io
->dev
->bus
->controller
,
289 "dev %s ep%d%s scatterlist error %d/%d\n",
291 usb_endpoint_num(&urb
->ep
->desc
),
292 usb_urb_dir_in(urb
) ? "in" : "out",
297 if (io
->status
== 0 && status
&& status
!= -ECONNRESET
) {
298 int i
, found
, retval
;
302 /* the previous urbs, and this one, completed already.
303 * unlink pending urbs so they won't rx/tx bad data.
304 * careful: unlink can sometimes be synchronous...
306 spin_unlock(&io
->lock
);
307 for (i
= 0, found
= 0; i
< io
->entries
; i
++) {
308 if (!io
->urbs
[i
] || !io
->urbs
[i
]->dev
)
311 retval
= usb_unlink_urb(io
->urbs
[i
]);
312 if (retval
!= -EINPROGRESS
&&
315 dev_err(&io
->dev
->dev
,
316 "%s, unlink --> %d\n",
318 } else if (urb
== io
->urbs
[i
])
321 spin_lock(&io
->lock
);
325 /* on the last completion, signal usb_sg_wait() */
326 io
->bytes
+= urb
->actual_length
;
329 complete(&io
->complete
);
331 spin_unlock(&io
->lock
);
336 * usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request
337 * @io: request block being initialized. until usb_sg_wait() returns,
338 * treat this as a pointer to an opaque block of memory,
339 * @dev: the usb device that will send or receive the data
340 * @pipe: endpoint "pipe" used to transfer the data
341 * @period: polling rate for interrupt endpoints, in frames or
342 * (for high speed endpoints) microframes; ignored for bulk
343 * @sg: scatterlist entries
344 * @nents: how many entries in the scatterlist
345 * @length: how many bytes to send from the scatterlist, or zero to
346 * send every byte identified in the list.
347 * @mem_flags: SLAB_* flags affecting memory allocations in this call
349 * Returns zero for success, else a negative errno value. This initializes a
350 * scatter/gather request, allocating resources such as I/O mappings and urb
351 * memory (except maybe memory used by USB controller drivers).
353 * The request must be issued using usb_sg_wait(), which waits for the I/O to
354 * complete (or to be canceled) and then cleans up all resources allocated by
357 * The request may be canceled with usb_sg_cancel(), either before or after
358 * usb_sg_wait() is called.
360 int usb_sg_init(struct usb_sg_request
*io
, struct usb_device
*dev
,
361 unsigned pipe
, unsigned period
, struct scatterlist
*sg
,
362 int nents
, size_t length
, gfp_t mem_flags
)
368 if (!io
|| !dev
|| !sg
369 || usb_pipecontrol(pipe
)
370 || usb_pipeisoc(pipe
)
374 spin_lock_init(&io
->lock
);
380 /* not all host controllers use DMA (like the mainstream pci ones);
381 * they can use PIO (sl811) or be software over another transport.
383 dma
= (dev
->dev
.dma_mask
!= NULL
);
385 io
->entries
= usb_buffer_map_sg(dev
, usb_pipein(pipe
),
390 /* initialize all the urbs we'll use */
391 if (io
->entries
<= 0)
394 io
->urbs
= kmalloc(io
->entries
* sizeof *io
->urbs
, mem_flags
);
398 urb_flags
= URB_NO_INTERRUPT
;
400 urb_flags
|= URB_NO_TRANSFER_DMA_MAP
;
401 if (usb_pipein(pipe
))
402 urb_flags
|= URB_SHORT_NOT_OK
;
404 for_each_sg(sg
, sg
, io
->entries
, i
) {
407 io
->urbs
[i
] = usb_alloc_urb(0, mem_flags
);
413 io
->urbs
[i
]->dev
= NULL
;
414 io
->urbs
[i
]->pipe
= pipe
;
415 io
->urbs
[i
]->interval
= period
;
416 io
->urbs
[i
]->transfer_flags
= urb_flags
;
418 io
->urbs
[i
]->complete
= sg_complete
;
419 io
->urbs
[i
]->context
= io
;
422 * Some systems need to revert to PIO when DMA is temporarily
423 * unavailable. For their sakes, both transfer_buffer and
424 * transfer_dma are set when possible. However this can only
425 * work on systems without:
427 * - HIGHMEM, since DMA buffers located in high memory are
428 * not directly addressable by the CPU for PIO;
430 * - IOMMU, since dma_map_sg() is allowed to use an IOMMU to
431 * make virtually discontiguous buffers be "dma-contiguous"
432 * so that PIO and DMA need diferent numbers of URBs.
434 * So when HIGHMEM or IOMMU are in use, transfer_buffer is NULL
435 * to prevent stale pointers and to help spot bugs.
438 io
->urbs
[i
]->transfer_dma
= sg_dma_address(sg
);
439 len
= sg_dma_len(sg
);
440 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_GART_IOMMU)
441 io
->urbs
[i
]->transfer_buffer
= NULL
;
443 io
->urbs
[i
]->transfer_buffer
= sg_virt(sg
);
446 /* hc may use _only_ transfer_buffer */
447 io
->urbs
[i
]->transfer_buffer
= sg_virt(sg
);
452 len
= min_t(unsigned, len
, length
);
457 io
->urbs
[i
]->transfer_buffer_length
= len
;
459 io
->urbs
[--i
]->transfer_flags
&= ~URB_NO_INTERRUPT
;
461 /* transaction state */
462 io
->count
= io
->entries
;
465 init_completion(&io
->complete
);
472 EXPORT_SYMBOL_GPL(usb_sg_init
);
475 * usb_sg_wait - synchronously execute scatter/gather request
476 * @io: request block handle, as initialized with usb_sg_init().
477 * some fields become accessible when this call returns.
478 * Context: !in_interrupt ()
480 * This function blocks until the specified I/O operation completes. It
481 * leverages the grouping of the related I/O requests to get good transfer
482 * rates, by queueing the requests. At higher speeds, such queuing can
483 * significantly improve USB throughput.
485 * There are three kinds of completion for this function.
486 * (1) success, where io->status is zero. The number of io->bytes
487 * transferred is as requested.
488 * (2) error, where io->status is a negative errno value. The number
489 * of io->bytes transferred before the error is usually less
490 * than requested, and can be nonzero.
491 * (3) cancellation, a type of error with status -ECONNRESET that
492 * is initiated by usb_sg_cancel().
494 * When this function returns, all memory allocated through usb_sg_init() or
495 * this call will have been freed. The request block parameter may still be
496 * passed to usb_sg_cancel(), or it may be freed. It could also be
497 * reinitialized and then reused.
499 * Data Transfer Rates:
501 * Bulk transfers are valid for full or high speed endpoints.
502 * The best full speed data rate is 19 packets of 64 bytes each
503 * per frame, or 1216 bytes per millisecond.
504 * The best high speed data rate is 13 packets of 512 bytes each
505 * per microframe, or 52 KBytes per millisecond.
507 * The reason to use interrupt transfers through this API would most likely
508 * be to reserve high speed bandwidth, where up to 24 KBytes per millisecond
509 * could be transferred. That capability is less useful for low or full
510 * speed interrupt endpoints, which allow at most one packet per millisecond,
511 * of at most 8 or 64 bytes (respectively).
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 retval
= usb_submit_urb(io
->urbs
[i
], GFP_ATOMIC
);
527 /* after we submit, let completions or cancelations fire;
528 * we handshake using io->status.
530 spin_unlock_irq(&io
->lock
);
532 /* maybe we retrying will recover */
533 case -ENXIO
: /* hc didn't queue this one */
536 io
->urbs
[i
]->dev
= NULL
;
541 /* no error? continue immediately.
543 * NOTE: to work better with UHCI (4K I/O buffer may
544 * need 3K of TDs) it may be good to limit how many
545 * URBs are queued at once; N milliseconds?
552 /* fail any uncompleted urbs */
554 io
->urbs
[i
]->dev
= NULL
;
555 io
->urbs
[i
]->status
= retval
;
556 dev_dbg(&io
->dev
->dev
, "%s, submit --> %d\n",
560 spin_lock_irq(&io
->lock
);
561 if (retval
&& (io
->status
== 0 || io
->status
== -ECONNRESET
))
564 io
->count
-= entries
- i
;
566 complete(&io
->complete
);
567 spin_unlock_irq(&io
->lock
);
569 /* OK, yes, this could be packaged as non-blocking.
570 * So could the submit loop above ... but it's easier to
571 * solve neither problem than to solve both!
573 wait_for_completion(&io
->complete
);
577 EXPORT_SYMBOL_GPL(usb_sg_wait
);
580 * usb_sg_cancel - stop scatter/gather i/o issued by usb_sg_wait()
581 * @io: request block, initialized with usb_sg_init()
583 * This stops a request after it has been started by usb_sg_wait().
584 * It can also prevents one initialized by usb_sg_init() from starting,
585 * so that call just frees resources allocated to the request.
587 void usb_sg_cancel(struct usb_sg_request
*io
)
591 spin_lock_irqsave(&io
->lock
, flags
);
593 /* shut everything down, if it didn't already */
597 io
->status
= -ECONNRESET
;
598 spin_unlock(&io
->lock
);
599 for (i
= 0; i
< io
->entries
; i
++) {
602 if (!io
->urbs
[i
]->dev
)
604 retval
= usb_unlink_urb(io
->urbs
[i
]);
605 if (retval
!= -EINPROGRESS
&& retval
!= -EBUSY
)
606 dev_warn(&io
->dev
->dev
, "%s, unlink --> %d\n",
609 spin_lock(&io
->lock
);
611 spin_unlock_irqrestore(&io
->lock
, flags
);
613 EXPORT_SYMBOL_GPL(usb_sg_cancel
);
615 /*-------------------------------------------------------------------*/
618 * usb_get_descriptor - issues a generic GET_DESCRIPTOR request
619 * @dev: the device whose descriptor is being retrieved
620 * @type: the descriptor type (USB_DT_*)
621 * @index: the number of the descriptor
622 * @buf: where to put the descriptor
623 * @size: how big is "buf"?
624 * Context: !in_interrupt ()
626 * Gets a USB descriptor. Convenience functions exist to simplify
627 * getting some types of descriptors. Use
628 * usb_get_string() or usb_string() for USB_DT_STRING.
629 * Device (USB_DT_DEVICE) and configuration descriptors (USB_DT_CONFIG)
630 * are part of the device structure.
631 * In addition to a number of USB-standard descriptors, some
632 * devices also use class-specific or vendor-specific descriptors.
634 * This call is synchronous, and may not be used in an interrupt context.
636 * Returns the number of bytes received on success, or else the status code
637 * returned by the underlying usb_control_msg() call.
639 int usb_get_descriptor(struct usb_device
*dev
, unsigned char type
,
640 unsigned char index
, void *buf
, int size
)
645 memset(buf
, 0, size
); /* Make sure we parse really received data */
647 for (i
= 0; i
< 3; ++i
) {
648 /* retry on length 0 or error; some devices are flakey */
649 result
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0),
650 USB_REQ_GET_DESCRIPTOR
, USB_DIR_IN
,
651 (type
<< 8) + index
, 0, buf
, size
,
652 USB_CTRL_GET_TIMEOUT
);
653 if (result
<= 0 && result
!= -ETIMEDOUT
)
655 if (result
> 1 && ((u8
*)buf
)[1] != type
) {
663 EXPORT_SYMBOL_GPL(usb_get_descriptor
);
666 * usb_get_string - gets a string descriptor
667 * @dev: the device whose string descriptor is being retrieved
668 * @langid: code for language chosen (from string descriptor zero)
669 * @index: the number of the descriptor
670 * @buf: where to put the string
671 * @size: how big is "buf"?
672 * Context: !in_interrupt ()
674 * Retrieves a string, encoded using UTF-16LE (Unicode, 16 bits per character,
675 * in little-endian byte order).
676 * The usb_string() function will often be a convenient way to turn
677 * these strings into kernel-printable form.
679 * Strings may be referenced in device, configuration, interface, or other
680 * descriptors, and could also be used in vendor-specific ways.
682 * This call is synchronous, and may not be used in an interrupt context.
684 * Returns the number of bytes received on success, or else the status code
685 * returned by the underlying usb_control_msg() call.
687 static int usb_get_string(struct usb_device
*dev
, unsigned short langid
,
688 unsigned char index
, void *buf
, int size
)
693 for (i
= 0; i
< 3; ++i
) {
694 /* retry on length 0 or stall; some devices are flakey */
695 result
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0),
696 USB_REQ_GET_DESCRIPTOR
, USB_DIR_IN
,
697 (USB_DT_STRING
<< 8) + index
, langid
, buf
, size
,
698 USB_CTRL_GET_TIMEOUT
);
699 if (result
== 0 || result
== -EPIPE
)
701 if (result
> 1 && ((u8
*) buf
)[1] != USB_DT_STRING
) {
710 static void usb_try_string_workarounds(unsigned char *buf
, int *length
)
712 int newlength
, oldlength
= *length
;
714 for (newlength
= 2; newlength
+ 1 < oldlength
; newlength
+= 2)
715 if (!isprint(buf
[newlength
]) || buf
[newlength
+ 1])
724 static int usb_string_sub(struct usb_device
*dev
, unsigned int langid
,
725 unsigned int index
, unsigned char *buf
)
729 /* Try to read the string descriptor by asking for the maximum
730 * possible number of bytes */
731 if (dev
->quirks
& USB_QUIRK_STRING_FETCH_255
)
734 rc
= usb_get_string(dev
, langid
, index
, buf
, 255);
736 /* If that failed try to read the descriptor length, then
737 * ask for just that many bytes */
739 rc
= usb_get_string(dev
, langid
, index
, buf
, 2);
741 rc
= usb_get_string(dev
, langid
, index
, buf
, buf
[0]);
745 if (!buf
[0] && !buf
[1])
746 usb_try_string_workarounds(buf
, &rc
);
748 /* There might be extra junk at the end of the descriptor */
752 rc
= rc
- (rc
& 1); /* force a multiple of two */
756 rc
= (rc
< 0 ? rc
: -EINVAL
);
762 * usb_string - returns ISO 8859-1 version of a string descriptor
763 * @dev: the device whose string descriptor is being retrieved
764 * @index: the number of the descriptor
765 * @buf: where to put the string
766 * @size: how big is "buf"?
767 * Context: !in_interrupt ()
769 * This converts the UTF-16LE encoded strings returned by devices, from
770 * usb_get_string_descriptor(), to null-terminated ISO-8859-1 encoded ones
771 * that are more usable in most kernel contexts. Note that all characters
772 * in the chosen descriptor that can't be encoded using ISO-8859-1
773 * are converted to the question mark ("?") character, and this function
774 * chooses strings in the first language supported by the device.
776 * The ASCII (or, redundantly, "US-ASCII") character set is the seven-bit
777 * subset of ISO 8859-1. ISO-8859-1 is the eight-bit subset of Unicode,
778 * and is appropriate for use many uses of English and several other
779 * Western European languages. (But it doesn't include the "Euro" symbol.)
781 * This call is synchronous, and may not be used in an interrupt context.
783 * Returns length of the string (>= 0) or usb_control_msg status (< 0).
785 int usb_string(struct usb_device
*dev
, int index
, char *buf
, size_t size
)
791 if (dev
->state
== USB_STATE_SUSPENDED
)
792 return -EHOSTUNREACH
;
793 if (size
<= 0 || !buf
|| !index
)
796 tbuf
= kmalloc(256, GFP_NOIO
);
800 /* get langid for strings if it's not yet known */
801 if (!dev
->have_langid
) {
802 err
= usb_string_sub(dev
, 0, 0, tbuf
);
805 "string descriptor 0 read error: %d\n",
808 } else if (err
< 4) {
809 dev_err(&dev
->dev
, "string descriptor 0 too short\n");
813 dev
->have_langid
= 1;
814 dev
->string_langid
= tbuf
[2] | (tbuf
[3] << 8);
815 /* always use the first langid listed */
816 dev_dbg(&dev
->dev
, "default language 0x%04x\n",
821 err
= usb_string_sub(dev
, dev
->string_langid
, index
, tbuf
);
825 size
--; /* leave room for trailing NULL char in output buffer */
826 for (idx
= 0, u
= 2; u
< err
; u
+= 2) {
829 if (tbuf
[u
+1]) /* high byte */
830 buf
[idx
++] = '?'; /* non ISO-8859-1 character */
832 buf
[idx
++] = tbuf
[u
];
837 if (tbuf
[1] != USB_DT_STRING
)
839 "wrong descriptor type %02x for string %d (\"%s\")\n",
840 tbuf
[1], index
, buf
);
846 EXPORT_SYMBOL_GPL(usb_string
);
849 * usb_cache_string - read a string descriptor and cache it for later use
850 * @udev: the device whose string descriptor is being read
851 * @index: the descriptor index
853 * Returns a pointer to a kmalloc'ed buffer containing the descriptor string,
854 * or NULL if the index is 0 or the string could not be read.
856 char *usb_cache_string(struct usb_device
*udev
, int index
)
859 char *smallbuf
= NULL
;
865 buf
= kmalloc(256, GFP_KERNEL
);
867 len
= usb_string(udev
, index
, buf
, 256);
869 smallbuf
= kmalloc(++len
, GFP_KERNEL
);
872 memcpy(smallbuf
, buf
, len
);
880 * usb_get_device_descriptor - (re)reads the device descriptor (usbcore)
881 * @dev: the device whose device descriptor is being updated
882 * @size: how much of the descriptor to read
883 * Context: !in_interrupt ()
885 * Updates the copy of the device descriptor stored in the device structure,
886 * which dedicates space for this purpose.
888 * Not exported, only for use by the core. If drivers really want to read
889 * the device descriptor directly, they can call usb_get_descriptor() with
890 * type = USB_DT_DEVICE and index = 0.
892 * This call is synchronous, and may not be used in an interrupt context.
894 * Returns the number of bytes received on success, or else the status code
895 * returned by the underlying usb_control_msg() call.
897 int usb_get_device_descriptor(struct usb_device
*dev
, unsigned int size
)
899 struct usb_device_descriptor
*desc
;
902 if (size
> sizeof(*desc
))
904 desc
= kmalloc(sizeof(*desc
), GFP_NOIO
);
908 ret
= usb_get_descriptor(dev
, USB_DT_DEVICE
, 0, desc
, size
);
910 memcpy(&dev
->descriptor
, desc
, size
);
916 * usb_get_status - issues a GET_STATUS call
917 * @dev: the device whose status is being checked
918 * @type: USB_RECIP_*; for device, interface, or endpoint
919 * @target: zero (for device), else interface or endpoint number
920 * @data: pointer to two bytes of bitmap data
921 * Context: !in_interrupt ()
923 * Returns device, interface, or endpoint status. Normally only of
924 * interest to see if the device is self powered, or has enabled the
925 * remote wakeup facility; or whether a bulk or interrupt endpoint
926 * is halted ("stalled").
928 * Bits in these status bitmaps are set using the SET_FEATURE request,
929 * and cleared using the CLEAR_FEATURE request. The usb_clear_halt()
930 * function should be used to clear halt ("stall") status.
932 * This call is synchronous, and may not be used in an interrupt context.
934 * Returns the number of bytes received on success, or else the status code
935 * returned by the underlying usb_control_msg() call.
937 int usb_get_status(struct usb_device
*dev
, int type
, int target
, void *data
)
940 u16
*status
= kmalloc(sizeof(*status
), GFP_KERNEL
);
945 ret
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0),
946 USB_REQ_GET_STATUS
, USB_DIR_IN
| type
, 0, target
, status
,
947 sizeof(*status
), USB_CTRL_GET_TIMEOUT
);
949 *(u16
*)data
= *status
;
953 EXPORT_SYMBOL_GPL(usb_get_status
);
956 * usb_clear_halt - tells device to clear endpoint halt/stall condition
957 * @dev: device whose endpoint is halted
958 * @pipe: endpoint "pipe" being cleared
959 * Context: !in_interrupt ()
961 * This is used to clear halt conditions for bulk and interrupt endpoints,
962 * as reported by URB completion status. Endpoints that are halted are
963 * sometimes referred to as being "stalled". Such endpoints are unable
964 * to transmit or receive data until the halt status is cleared. Any URBs
965 * queued for such an endpoint should normally be unlinked by the driver
966 * before clearing the halt condition, as described in sections 5.7.5
967 * and 5.8.5 of the USB 2.0 spec.
969 * Note that control and isochronous endpoints don't halt, although control
970 * endpoints report "protocol stall" (for unsupported requests) using the
971 * same status code used to report a true stall.
973 * This call is synchronous, and may not be used in an interrupt context.
975 * Returns zero on success, or else the status code returned by the
976 * underlying usb_control_msg() call.
978 int usb_clear_halt(struct usb_device
*dev
, int pipe
)
981 int endp
= usb_pipeendpoint(pipe
);
983 if (usb_pipein(pipe
))
986 /* we don't care if it wasn't halted first. in fact some devices
987 * (like some ibmcam model 1 units) seem to expect hosts to make
988 * this request for iso endpoints, which can't halt!
990 result
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
991 USB_REQ_CLEAR_FEATURE
, USB_RECIP_ENDPOINT
,
992 USB_ENDPOINT_HALT
, endp
, NULL
, 0,
993 USB_CTRL_SET_TIMEOUT
);
995 /* don't un-halt or force to DATA0 except on success */
999 /* NOTE: seems like Microsoft and Apple don't bother verifying
1000 * the clear "took", so some devices could lock up if you check...
1001 * such as the Hagiwara FlashGate DUAL. So we won't bother.
1003 * NOTE: make sure the logic here doesn't diverge much from
1004 * the copy in usb-storage, for as long as we need two copies.
1007 /* toggle was reset by the clear */
1008 usb_settoggle(dev
, usb_pipeendpoint(pipe
), usb_pipeout(pipe
), 0);
1012 EXPORT_SYMBOL_GPL(usb_clear_halt
);
1014 static int create_intf_ep_devs(struct usb_interface
*intf
)
1016 struct usb_device
*udev
= interface_to_usbdev(intf
);
1017 struct usb_host_interface
*alt
= intf
->cur_altsetting
;
1020 if (intf
->ep_devs_created
|| intf
->unregistering
)
1023 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; ++i
)
1024 (void) usb_create_ep_devs(&intf
->dev
, &alt
->endpoint
[i
], udev
);
1025 intf
->ep_devs_created
= 1;
1029 static void remove_intf_ep_devs(struct usb_interface
*intf
)
1031 struct usb_host_interface
*alt
= intf
->cur_altsetting
;
1034 if (!intf
->ep_devs_created
)
1037 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; ++i
)
1038 usb_remove_ep_devs(&alt
->endpoint
[i
]);
1039 intf
->ep_devs_created
= 0;
1043 * usb_disable_endpoint -- Disable an endpoint by address
1044 * @dev: the device whose endpoint is being disabled
1045 * @epaddr: the endpoint's address. Endpoint number for output,
1046 * endpoint number + USB_DIR_IN for input
1047 * @reset_hardware: flag to erase any endpoint state stored in the
1048 * controller hardware
1050 * Disables the endpoint for URB submission and nukes all pending URBs.
1051 * If @reset_hardware is set then also deallocates hcd/hardware state
1054 void usb_disable_endpoint(struct usb_device
*dev
, unsigned int epaddr
,
1055 bool reset_hardware
)
1057 unsigned int epnum
= epaddr
& USB_ENDPOINT_NUMBER_MASK
;
1058 struct usb_host_endpoint
*ep
;
1063 if (usb_endpoint_out(epaddr
)) {
1064 ep
= dev
->ep_out
[epnum
];
1066 dev
->ep_out
[epnum
] = NULL
;
1068 ep
= dev
->ep_in
[epnum
];
1070 dev
->ep_in
[epnum
] = NULL
;
1074 usb_hcd_flush_endpoint(dev
, ep
);
1076 usb_hcd_disable_endpoint(dev
, ep
);
1081 * usb_disable_interface -- Disable all endpoints for an interface
1082 * @dev: the device whose interface is being disabled
1083 * @intf: pointer to the interface descriptor
1084 * @reset_hardware: flag to erase any endpoint state stored in the
1085 * controller hardware
1087 * Disables all the endpoints for the interface's current altsetting.
1089 void usb_disable_interface(struct usb_device
*dev
, struct usb_interface
*intf
,
1090 bool reset_hardware
)
1092 struct usb_host_interface
*alt
= intf
->cur_altsetting
;
1095 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; ++i
) {
1096 usb_disable_endpoint(dev
,
1097 alt
->endpoint
[i
].desc
.bEndpointAddress
,
1103 * usb_disable_device - Disable all the endpoints for a USB device
1104 * @dev: the device whose endpoints are being disabled
1105 * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
1107 * Disables all the device's endpoints, potentially including endpoint 0.
1108 * Deallocates hcd/hardware state for the endpoints (nuking all or most
1109 * pending urbs) and usbcore state for the interfaces, so that usbcore
1110 * must usb_set_configuration() before any interfaces could be used.
1112 void usb_disable_device(struct usb_device
*dev
, int skip_ep0
)
1116 dev_dbg(&dev
->dev
, "%s nuking %s URBs\n", __func__
,
1117 skip_ep0
? "non-ep0" : "all");
1118 for (i
= skip_ep0
; i
< 16; ++i
) {
1119 usb_disable_endpoint(dev
, i
, true);
1120 usb_disable_endpoint(dev
, i
+ USB_DIR_IN
, true);
1122 dev
->toggle
[0] = dev
->toggle
[1] = 0;
1124 /* getting rid of interfaces will disconnect
1125 * any drivers bound to them (a key side effect)
1127 if (dev
->actconfig
) {
1128 for (i
= 0; i
< dev
->actconfig
->desc
.bNumInterfaces
; i
++) {
1129 struct usb_interface
*interface
;
1131 /* remove this interface if it has been registered */
1132 interface
= dev
->actconfig
->interface
[i
];
1133 if (!device_is_registered(&interface
->dev
))
1135 dev_dbg(&dev
->dev
, "unregistering interface %s\n",
1136 dev_name(&interface
->dev
));
1137 interface
->unregistering
= 1;
1138 remove_intf_ep_devs(interface
);
1139 device_del(&interface
->dev
);
1142 /* Now that the interfaces are unbound, nobody should
1143 * try to access them.
1145 for (i
= 0; i
< dev
->actconfig
->desc
.bNumInterfaces
; i
++) {
1146 put_device(&dev
->actconfig
->interface
[i
]->dev
);
1147 dev
->actconfig
->interface
[i
] = NULL
;
1149 dev
->actconfig
= NULL
;
1150 if (dev
->state
== USB_STATE_CONFIGURED
)
1151 usb_set_device_state(dev
, USB_STATE_ADDRESS
);
1156 * usb_enable_endpoint - Enable an endpoint for USB communications
1157 * @dev: the device whose interface is being enabled
1159 * @reset_toggle: flag to set the endpoint's toggle back to 0
1161 * Resets the endpoint toggle if asked, and sets dev->ep_{in,out} pointers.
1162 * For control endpoints, both the input and output sides are handled.
1164 void usb_enable_endpoint(struct usb_device
*dev
, struct usb_host_endpoint
*ep
,
1167 int epnum
= usb_endpoint_num(&ep
->desc
);
1168 int is_out
= usb_endpoint_dir_out(&ep
->desc
);
1169 int is_control
= usb_endpoint_xfer_control(&ep
->desc
);
1171 if (is_out
|| is_control
) {
1173 usb_settoggle(dev
, epnum
, 1, 0);
1174 dev
->ep_out
[epnum
] = ep
;
1176 if (!is_out
|| is_control
) {
1178 usb_settoggle(dev
, epnum
, 0, 0);
1179 dev
->ep_in
[epnum
] = ep
;
1185 * usb_enable_interface - Enable all the endpoints for an interface
1186 * @dev: the device whose interface is being enabled
1187 * @intf: pointer to the interface descriptor
1188 * @reset_toggles: flag to set the endpoints' toggles back to 0
1190 * Enables all the endpoints for the interface's current altsetting.
1192 void usb_enable_interface(struct usb_device
*dev
,
1193 struct usb_interface
*intf
, bool reset_toggles
)
1195 struct usb_host_interface
*alt
= intf
->cur_altsetting
;
1198 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; ++i
)
1199 usb_enable_endpoint(dev
, &alt
->endpoint
[i
], reset_toggles
);
1203 * usb_set_interface - Makes a particular alternate setting be current
1204 * @dev: the device whose interface is being updated
1205 * @interface: the interface being updated
1206 * @alternate: the setting being chosen.
1207 * Context: !in_interrupt ()
1209 * This is used to enable data transfers on interfaces that may not
1210 * be enabled by default. Not all devices support such configurability.
1211 * Only the driver bound to an interface may change its setting.
1213 * Within any given configuration, each interface may have several
1214 * alternative settings. These are often used to control levels of
1215 * bandwidth consumption. For example, the default setting for a high
1216 * speed interrupt endpoint may not send more than 64 bytes per microframe,
1217 * while interrupt transfers of up to 3KBytes per microframe are legal.
1218 * Also, isochronous endpoints may never be part of an
1219 * interface's default setting. To access such bandwidth, alternate
1220 * interface settings must be made current.
1222 * Note that in the Linux USB subsystem, bandwidth associated with
1223 * an endpoint in a given alternate setting is not reserved until an URB
1224 * is submitted that needs that bandwidth. Some other operating systems
1225 * allocate bandwidth early, when a configuration is chosen.
1227 * This call is synchronous, and may not be used in an interrupt context.
1228 * Also, drivers must not change altsettings while urbs are scheduled for
1229 * endpoints in that interface; all such urbs must first be completed
1230 * (perhaps forced by unlinking).
1232 * Returns zero on success, or else the status code returned by the
1233 * underlying usb_control_msg() call.
1235 int usb_set_interface(struct usb_device
*dev
, int interface
, int alternate
)
1237 struct usb_interface
*iface
;
1238 struct usb_host_interface
*alt
;
1241 unsigned int epaddr
;
1244 if (dev
->state
== USB_STATE_SUSPENDED
)
1245 return -EHOSTUNREACH
;
1247 iface
= usb_ifnum_to_if(dev
, interface
);
1249 dev_dbg(&dev
->dev
, "selecting invalid interface %d\n",
1254 alt
= usb_altnum_to_altsetting(iface
, alternate
);
1256 dev_warn(&dev
->dev
, "selecting invalid altsetting %d",
1261 if (dev
->quirks
& USB_QUIRK_NO_SET_INTF
)
1264 ret
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
1265 USB_REQ_SET_INTERFACE
, USB_RECIP_INTERFACE
,
1266 alternate
, interface
, NULL
, 0, 5000);
1268 /* 9.4.10 says devices don't need this and are free to STALL the
1269 * request if the interface only has one alternate setting.
1271 if (ret
== -EPIPE
&& iface
->num_altsetting
== 1) {
1273 "manual set_interface for iface %d, alt %d\n",
1274 interface
, alternate
);
1279 /* FIXME drivers shouldn't need to replicate/bugfix the logic here
1280 * when they implement async or easily-killable versions of this or
1281 * other "should-be-internal" functions (like clear_halt).
1282 * should hcd+usbcore postprocess control requests?
1285 /* prevent submissions using previous endpoint settings */
1286 if (iface
->cur_altsetting
!= alt
) {
1287 remove_intf_ep_devs(iface
);
1288 usb_remove_sysfs_intf_files(iface
);
1290 usb_disable_interface(dev
, iface
, true);
1292 iface
->cur_altsetting
= alt
;
1294 /* If the interface only has one altsetting and the device didn't
1295 * accept the request, we attempt to carry out the equivalent action
1296 * by manually clearing the HALT feature for each endpoint in the
1302 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; i
++) {
1303 epaddr
= alt
->endpoint
[i
].desc
.bEndpointAddress
;
1304 pipe
= __create_pipe(dev
,
1305 USB_ENDPOINT_NUMBER_MASK
& epaddr
) |
1306 (usb_endpoint_out(epaddr
) ?
1307 USB_DIR_OUT
: USB_DIR_IN
);
1309 usb_clear_halt(dev
, pipe
);
1313 /* 9.1.1.5: reset toggles for all endpoints in the new altsetting
1316 * Despite EP0 is always present in all interfaces/AS, the list of
1317 * endpoints from the descriptor does not contain EP0. Due to its
1318 * omnipresence one might expect EP0 being considered "affected" by
1319 * any SetInterface request and hence assume toggles need to be reset.
1320 * However, EP0 toggles are re-synced for every individual transfer
1321 * during the SETUP stage - hence EP0 toggles are "don't care" here.
1322 * (Likewise, EP0 never "halts" on well designed devices.)
1324 usb_enable_interface(dev
, iface
, true);
1325 if (device_is_registered(&iface
->dev
)) {
1326 usb_create_sysfs_intf_files(iface
);
1327 create_intf_ep_devs(iface
);
1331 EXPORT_SYMBOL_GPL(usb_set_interface
);
1334 * usb_reset_configuration - lightweight device reset
1335 * @dev: the device whose configuration is being reset
1337 * This issues a standard SET_CONFIGURATION request to the device using
1338 * the current configuration. The effect is to reset most USB-related
1339 * state in the device, including interface altsettings (reset to zero),
1340 * endpoint halts (cleared), and data toggle (only for bulk and interrupt
1341 * endpoints). Other usbcore state is unchanged, including bindings of
1342 * usb device drivers to interfaces.
1344 * Because this affects multiple interfaces, avoid using this with composite
1345 * (multi-interface) devices. Instead, the driver for each interface may
1346 * use usb_set_interface() on the interfaces it claims. Be careful though;
1347 * some devices don't support the SET_INTERFACE request, and others won't
1348 * reset all the interface state (notably data toggles). Resetting the whole
1349 * configuration would affect other drivers' interfaces.
1351 * The caller must own the device lock.
1353 * Returns zero on success, else a negative error code.
1355 int usb_reset_configuration(struct usb_device
*dev
)
1358 struct usb_host_config
*config
;
1360 if (dev
->state
== USB_STATE_SUSPENDED
)
1361 return -EHOSTUNREACH
;
1363 /* caller must have locked the device and must own
1364 * the usb bus readlock (so driver bindings are stable);
1365 * calls during probe() are fine
1368 for (i
= 1; i
< 16; ++i
) {
1369 usb_disable_endpoint(dev
, i
, true);
1370 usb_disable_endpoint(dev
, i
+ USB_DIR_IN
, true);
1373 config
= dev
->actconfig
;
1374 retval
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
1375 USB_REQ_SET_CONFIGURATION
, 0,
1376 config
->desc
.bConfigurationValue
, 0,
1377 NULL
, 0, USB_CTRL_SET_TIMEOUT
);
1381 dev
->toggle
[0] = dev
->toggle
[1] = 0;
1383 /* re-init hc/hcd interface/endpoint state */
1384 for (i
= 0; i
< config
->desc
.bNumInterfaces
; i
++) {
1385 struct usb_interface
*intf
= config
->interface
[i
];
1386 struct usb_host_interface
*alt
;
1388 alt
= usb_altnum_to_altsetting(intf
, 0);
1390 /* No altsetting 0? We'll assume the first altsetting.
1391 * We could use a GetInterface call, but if a device is
1392 * so non-compliant that it doesn't have altsetting 0
1393 * then I wouldn't trust its reply anyway.
1396 alt
= &intf
->altsetting
[0];
1398 if (alt
!= intf
->cur_altsetting
) {
1399 remove_intf_ep_devs(intf
);
1400 usb_remove_sysfs_intf_files(intf
);
1402 intf
->cur_altsetting
= alt
;
1403 usb_enable_interface(dev
, intf
, true);
1404 if (device_is_registered(&intf
->dev
)) {
1405 usb_create_sysfs_intf_files(intf
);
1406 create_intf_ep_devs(intf
);
1411 EXPORT_SYMBOL_GPL(usb_reset_configuration
);
1413 static void usb_release_interface(struct device
*dev
)
1415 struct usb_interface
*intf
= to_usb_interface(dev
);
1416 struct usb_interface_cache
*intfc
=
1417 altsetting_to_usb_interface_cache(intf
->altsetting
);
1419 kref_put(&intfc
->ref
, usb_release_interface_cache
);
1423 #ifdef CONFIG_HOTPLUG
1424 static int usb_if_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
1426 struct usb_device
*usb_dev
;
1427 struct usb_interface
*intf
;
1428 struct usb_host_interface
*alt
;
1430 intf
= to_usb_interface(dev
);
1431 usb_dev
= interface_to_usbdev(intf
);
1432 alt
= intf
->cur_altsetting
;
1434 if (add_uevent_var(env
, "INTERFACE=%d/%d/%d",
1435 alt
->desc
.bInterfaceClass
,
1436 alt
->desc
.bInterfaceSubClass
,
1437 alt
->desc
.bInterfaceProtocol
))
1440 if (add_uevent_var(env
,
1442 "v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02X",
1443 le16_to_cpu(usb_dev
->descriptor
.idVendor
),
1444 le16_to_cpu(usb_dev
->descriptor
.idProduct
),
1445 le16_to_cpu(usb_dev
->descriptor
.bcdDevice
),
1446 usb_dev
->descriptor
.bDeviceClass
,
1447 usb_dev
->descriptor
.bDeviceSubClass
,
1448 usb_dev
->descriptor
.bDeviceProtocol
,
1449 alt
->desc
.bInterfaceClass
,
1450 alt
->desc
.bInterfaceSubClass
,
1451 alt
->desc
.bInterfaceProtocol
))
1459 static int usb_if_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
1463 #endif /* CONFIG_HOTPLUG */
1465 struct device_type usb_if_device_type
= {
1466 .name
= "usb_interface",
1467 .release
= usb_release_interface
,
1468 .uevent
= usb_if_uevent
,
1471 static struct usb_interface_assoc_descriptor
*find_iad(struct usb_device
*dev
,
1472 struct usb_host_config
*config
,
1475 struct usb_interface_assoc_descriptor
*retval
= NULL
;
1476 struct usb_interface_assoc_descriptor
*intf_assoc
;
1481 for (i
= 0; (i
< USB_MAXIADS
&& config
->intf_assoc
[i
]); i
++) {
1482 intf_assoc
= config
->intf_assoc
[i
];
1483 if (intf_assoc
->bInterfaceCount
== 0)
1486 first_intf
= intf_assoc
->bFirstInterface
;
1487 last_intf
= first_intf
+ (intf_assoc
->bInterfaceCount
- 1);
1488 if (inum
>= first_intf
&& inum
<= last_intf
) {
1490 retval
= intf_assoc
;
1492 dev_err(&dev
->dev
, "Interface #%d referenced"
1493 " by multiple IADs\n", inum
);
1502 * Internal function to queue a device reset
1504 * This is initialized into the workstruct in 'struct
1505 * usb_device->reset_ws' that is launched by
1506 * message.c:usb_set_configuration() when initializing each 'struct
1509 * It is safe to get the USB device without reference counts because
1510 * the life cycle of @iface is bound to the life cycle of @udev. Then,
1511 * this function will be ran only if @iface is alive (and before
1512 * freeing it any scheduled instances of it will have been cancelled).
1514 * We need to set a flag (usb_dev->reset_running) because when we call
1515 * the reset, the interfaces might be unbound. The current interface
1516 * cannot try to remove the queued work as it would cause a deadlock
1517 * (you cannot remove your work from within your executing
1518 * workqueue). This flag lets it know, so that
1519 * usb_cancel_queued_reset() doesn't try to do it.
1521 * See usb_queue_reset_device() for more details
1523 void __usb_queue_reset_device(struct work_struct
*ws
)
1526 struct usb_interface
*iface
=
1527 container_of(ws
, struct usb_interface
, reset_ws
);
1528 struct usb_device
*udev
= interface_to_usbdev(iface
);
1530 rc
= usb_lock_device_for_reset(udev
, iface
);
1532 iface
->reset_running
= 1;
1533 usb_reset_device(udev
);
1534 iface
->reset_running
= 0;
1535 usb_unlock_device(udev
);
1541 * usb_set_configuration - Makes a particular device setting be current
1542 * @dev: the device whose configuration is being updated
1543 * @configuration: the configuration being chosen.
1544 * Context: !in_interrupt(), caller owns the device lock
1546 * This is used to enable non-default device modes. Not all devices
1547 * use this kind of configurability; many devices only have one
1550 * @configuration is the value of the configuration to be installed.
1551 * According to the USB spec (e.g. section 9.1.1.5), configuration values
1552 * must be non-zero; a value of zero indicates that the device in
1553 * unconfigured. However some devices erroneously use 0 as one of their
1554 * configuration values. To help manage such devices, this routine will
1555 * accept @configuration = -1 as indicating the device should be put in
1556 * an unconfigured state.
1558 * USB device configurations may affect Linux interoperability,
1559 * power consumption and the functionality available. For example,
1560 * the default configuration is limited to using 100mA of bus power,
1561 * so that when certain device functionality requires more power,
1562 * and the device is bus powered, that functionality should be in some
1563 * non-default device configuration. Other device modes may also be
1564 * reflected as configuration options, such as whether two ISDN
1565 * channels are available independently; and choosing between open
1566 * standard device protocols (like CDC) or proprietary ones.
1568 * Note that a non-authorized device (dev->authorized == 0) will only
1569 * be put in unconfigured mode.
1571 * Note that USB has an additional level of device configurability,
1572 * associated with interfaces. That configurability is accessed using
1573 * usb_set_interface().
1575 * This call is synchronous. The calling context must be able to sleep,
1576 * must own the device lock, and must not hold the driver model's USB
1577 * bus mutex; usb interface driver probe() methods cannot use this routine.
1579 * Returns zero on success, or else the status code returned by the
1580 * underlying call that failed. On successful completion, each interface
1581 * in the original device configuration has been destroyed, and each one
1582 * in the new configuration has been probed by all relevant usb device
1583 * drivers currently known to the kernel.
1585 int usb_set_configuration(struct usb_device
*dev
, int configuration
)
1588 struct usb_host_config
*cp
= NULL
;
1589 struct usb_interface
**new_interfaces
= NULL
;
1592 if (dev
->authorized
== 0 || configuration
== -1)
1595 for (i
= 0; i
< dev
->descriptor
.bNumConfigurations
; i
++) {
1596 if (dev
->config
[i
].desc
.bConfigurationValue
==
1598 cp
= &dev
->config
[i
];
1603 if ((!cp
&& configuration
!= 0))
1606 /* The USB spec says configuration 0 means unconfigured.
1607 * But if a device includes a configuration numbered 0,
1608 * we will accept it as a correctly configured state.
1609 * Use -1 if you really want to unconfigure the device.
1611 if (cp
&& configuration
== 0)
1612 dev_warn(&dev
->dev
, "config 0 descriptor??\n");
1614 /* Allocate memory for new interfaces before doing anything else,
1615 * so that if we run out then nothing will have changed. */
1618 nintf
= cp
->desc
.bNumInterfaces
;
1619 new_interfaces
= kmalloc(nintf
* sizeof(*new_interfaces
),
1621 if (!new_interfaces
) {
1622 dev_err(&dev
->dev
, "Out of memory\n");
1626 for (; n
< nintf
; ++n
) {
1627 new_interfaces
[n
] = kzalloc(
1628 sizeof(struct usb_interface
),
1630 if (!new_interfaces
[n
]) {
1631 dev_err(&dev
->dev
, "Out of memory\n");
1635 kfree(new_interfaces
[n
]);
1636 kfree(new_interfaces
);
1641 i
= dev
->bus_mA
- cp
->desc
.bMaxPower
* 2;
1643 dev_warn(&dev
->dev
, "new config #%d exceeds power "
1648 /* Wake up the device so we can send it the Set-Config request */
1649 ret
= usb_autoresume_device(dev
);
1651 goto free_interfaces
;
1653 /* if it's already configured, clear out old state first.
1654 * getting rid of old interfaces means unbinding their drivers.
1656 if (dev
->state
!= USB_STATE_ADDRESS
)
1657 usb_disable_device(dev
, 1); /* Skip ep0 */
1659 /* Get rid of pending async Set-Config requests for this device */
1660 cancel_async_set_config(dev
);
1662 ret
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
1663 USB_REQ_SET_CONFIGURATION
, 0, configuration
, 0,
1664 NULL
, 0, USB_CTRL_SET_TIMEOUT
);
1666 /* All the old state is gone, so what else can we do?
1667 * The device is probably useless now anyway.
1672 dev
->actconfig
= cp
;
1674 usb_set_device_state(dev
, USB_STATE_ADDRESS
);
1675 usb_autosuspend_device(dev
);
1676 goto free_interfaces
;
1678 usb_set_device_state(dev
, USB_STATE_CONFIGURED
);
1680 /* Initialize the new interface structures and the
1681 * hc/hcd/usbcore interface/endpoint state.
1683 for (i
= 0; i
< nintf
; ++i
) {
1684 struct usb_interface_cache
*intfc
;
1685 struct usb_interface
*intf
;
1686 struct usb_host_interface
*alt
;
1688 cp
->interface
[i
] = intf
= new_interfaces
[i
];
1689 intfc
= cp
->intf_cache
[i
];
1690 intf
->altsetting
= intfc
->altsetting
;
1691 intf
->num_altsetting
= intfc
->num_altsetting
;
1692 intf
->intf_assoc
= find_iad(dev
, cp
, i
);
1693 kref_get(&intfc
->ref
);
1695 alt
= usb_altnum_to_altsetting(intf
, 0);
1697 /* No altsetting 0? We'll assume the first altsetting.
1698 * We could use a GetInterface call, but if a device is
1699 * so non-compliant that it doesn't have altsetting 0
1700 * then I wouldn't trust its reply anyway.
1703 alt
= &intf
->altsetting
[0];
1705 intf
->cur_altsetting
= alt
;
1706 usb_enable_interface(dev
, intf
, true);
1707 intf
->dev
.parent
= &dev
->dev
;
1708 intf
->dev
.driver
= NULL
;
1709 intf
->dev
.bus
= &usb_bus_type
;
1710 intf
->dev
.type
= &usb_if_device_type
;
1711 intf
->dev
.groups
= usb_interface_groups
;
1712 intf
->dev
.dma_mask
= dev
->dev
.dma_mask
;
1713 INIT_WORK(&intf
->reset_ws
, __usb_queue_reset_device
);
1714 device_initialize(&intf
->dev
);
1715 mark_quiesced(intf
);
1716 dev_set_name(&intf
->dev
, "%d-%s:%d.%d",
1717 dev
->bus
->busnum
, dev
->devpath
,
1718 configuration
, alt
->desc
.bInterfaceNumber
);
1720 kfree(new_interfaces
);
1722 if (cp
->string
== NULL
)
1723 cp
->string
= usb_cache_string(dev
, cp
->desc
.iConfiguration
);
1725 /* Now that all the interfaces are set up, register them
1726 * to trigger binding of drivers to interfaces. probe()
1727 * routines may install different altsettings and may
1728 * claim() any interfaces not yet bound. Many class drivers
1729 * need that: CDC, audio, video, etc.
1731 for (i
= 0; i
< nintf
; ++i
) {
1732 struct usb_interface
*intf
= cp
->interface
[i
];
1735 "adding %s (config #%d, interface %d)\n",
1736 dev_name(&intf
->dev
), configuration
,
1737 intf
->cur_altsetting
->desc
.bInterfaceNumber
);
1738 ret
= device_add(&intf
->dev
);
1740 dev_err(&dev
->dev
, "device_add(%s) --> %d\n",
1741 dev_name(&intf
->dev
), ret
);
1744 create_intf_ep_devs(intf
);
1747 usb_autosuspend_device(dev
);
1751 static LIST_HEAD(set_config_list
);
1752 static DEFINE_SPINLOCK(set_config_lock
);
1754 struct set_config_request
{
1755 struct usb_device
*udev
;
1757 struct work_struct work
;
1758 struct list_head node
;
1761 /* Worker routine for usb_driver_set_configuration() */
1762 static void driver_set_config_work(struct work_struct
*work
)
1764 struct set_config_request
*req
=
1765 container_of(work
, struct set_config_request
, work
);
1766 struct usb_device
*udev
= req
->udev
;
1768 usb_lock_device(udev
);
1769 spin_lock(&set_config_lock
);
1770 list_del(&req
->node
);
1771 spin_unlock(&set_config_lock
);
1773 if (req
->config
>= -1) /* Is req still valid? */
1774 usb_set_configuration(udev
, req
->config
);
1775 usb_unlock_device(udev
);
1780 /* Cancel pending Set-Config requests for a device whose configuration
1783 static void cancel_async_set_config(struct usb_device
*udev
)
1785 struct set_config_request
*req
;
1787 spin_lock(&set_config_lock
);
1788 list_for_each_entry(req
, &set_config_list
, node
) {
1789 if (req
->udev
== udev
)
1790 req
->config
= -999; /* Mark as cancelled */
1792 spin_unlock(&set_config_lock
);
1796 * usb_driver_set_configuration - Provide a way for drivers to change device configurations
1797 * @udev: the device whose configuration is being updated
1798 * @config: the configuration being chosen.
1799 * Context: In process context, must be able to sleep
1801 * Device interface drivers are not allowed to change device configurations.
1802 * This is because changing configurations will destroy the interface the
1803 * driver is bound to and create new ones; it would be like a floppy-disk
1804 * driver telling the computer to replace the floppy-disk drive with a
1807 * Still, in certain specialized circumstances the need may arise. This
1808 * routine gets around the normal restrictions by using a work thread to
1809 * submit the change-config request.
1811 * Returns 0 if the request was succesfully queued, error code otherwise.
1812 * The caller has no way to know whether the queued request will eventually
1815 int usb_driver_set_configuration(struct usb_device
*udev
, int config
)
1817 struct set_config_request
*req
;
1819 req
= kmalloc(sizeof(*req
), GFP_KERNEL
);
1823 req
->config
= config
;
1824 INIT_WORK(&req
->work
, driver_set_config_work
);
1826 spin_lock(&set_config_lock
);
1827 list_add(&req
->node
, &set_config_list
);
1828 spin_unlock(&set_config_lock
);
1831 schedule_work(&req
->work
);
1834 EXPORT_SYMBOL_GPL(usb_driver_set_configuration
);