2 * message.c - synchronous message handling
5 #include <linux/pci.h> /* for scatterlist macros */
7 #include <linux/module.h>
8 #include <linux/slab.h>
9 #include <linux/init.h>
11 #include <linux/timer.h>
12 #include <linux/ctype.h>
13 #include <linux/nls.h>
14 #include <linux/device.h>
15 #include <linux/scatterlist.h>
16 #include <linux/usb/quirks.h>
17 #include <asm/byteorder.h>
19 #include "hcd.h" /* for usbcore internals */
22 static void cancel_async_set_config(struct usb_device
*udev
);
25 struct completion done
;
29 static void usb_api_blocking_completion(struct urb
*urb
)
31 struct api_context
*ctx
= urb
->context
;
33 ctx
->status
= urb
->status
;
39 * Starts urb and waits for completion or timeout. Note that this call
40 * is NOT interruptible. Many device driver i/o requests should be
41 * interruptible and therefore these drivers should implement their
42 * own interruptible routines.
44 static int usb_start_wait_urb(struct urb
*urb
, int timeout
, int *actual_length
)
46 struct api_context ctx
;
50 init_completion(&ctx
.done
);
52 urb
->actual_length
= 0;
53 retval
= usb_submit_urb(urb
, GFP_NOIO
);
57 expire
= timeout
? msecs_to_jiffies(timeout
) : MAX_SCHEDULE_TIMEOUT
;
58 if (!wait_for_completion_timeout(&ctx
.done
, expire
)) {
60 retval
= (ctx
.status
== -ENOENT
? -ETIMEDOUT
: ctx
.status
);
62 dev_dbg(&urb
->dev
->dev
,
63 "%s timed out on ep%d%s len=%u/%u\n",
65 usb_endpoint_num(&urb
->ep
->desc
),
66 usb_urb_dir_in(urb
) ? "in" : "out",
68 urb
->transfer_buffer_length
);
73 *actual_length
= urb
->actual_length
;
79 /*-------------------------------------------------------------------*/
80 /* returns status (negative) or length (positive) */
81 static int usb_internal_control_msg(struct usb_device
*usb_dev
,
83 struct usb_ctrlrequest
*cmd
,
84 void *data
, int len
, int timeout
)
90 urb
= usb_alloc_urb(0, GFP_NOIO
);
94 usb_fill_control_urb(urb
, usb_dev
, pipe
, (unsigned char *)cmd
, data
,
95 len
, usb_api_blocking_completion
, NULL
);
97 retv
= usb_start_wait_urb(urb
, timeout
, &length
);
105 * usb_control_msg - Builds a control urb, sends it off and waits for completion
106 * @dev: pointer to the usb device to send the message to
107 * @pipe: endpoint "pipe" to send the message to
108 * @request: USB message request value
109 * @requesttype: USB message request type value
110 * @value: USB message value
111 * @index: USB message index value
112 * @data: pointer to the data to send
113 * @size: length in bytes of the data to send
114 * @timeout: time in msecs to wait for the message to complete before timing
115 * out (if 0 the wait is forever)
117 * Context: !in_interrupt ()
119 * This function sends a simple control message to a specified endpoint and
120 * waits for the message to complete, or timeout.
122 * If successful, it returns the number of bytes transferred, otherwise a
123 * negative error number.
125 * Don't use this function from within an interrupt context, like a bottom half
126 * handler. If you need an asynchronous message, or need to send a message
127 * from within interrupt context, use usb_submit_urb().
128 * If a thread in your driver uses this call, make sure your disconnect()
129 * method can wait for it to complete. Since you don't have a handle on the
130 * URB used, you can't cancel the request.
132 int usb_control_msg(struct usb_device
*dev
, unsigned int pipe
, __u8 request
,
133 __u8 requesttype
, __u16 value
, __u16 index
, void *data
,
134 __u16 size
, int timeout
)
136 struct usb_ctrlrequest
*dr
;
139 dr
= kmalloc(sizeof(struct usb_ctrlrequest
), GFP_NOIO
);
143 dr
->bRequestType
= requesttype
;
144 dr
->bRequest
= request
;
145 dr
->wValue
= cpu_to_le16(value
);
146 dr
->wIndex
= cpu_to_le16(index
);
147 dr
->wLength
= cpu_to_le16(size
);
149 /* dbg("usb_control_msg"); */
151 ret
= usb_internal_control_msg(dev
, pipe
, dr
, data
, size
, timeout
);
157 EXPORT_SYMBOL_GPL(usb_control_msg
);
160 * usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for completion
161 * @usb_dev: pointer to the usb device to send the message to
162 * @pipe: endpoint "pipe" to send the message to
163 * @data: pointer to the data to send
164 * @len: length in bytes of the data to send
165 * @actual_length: pointer to a location to put the actual length transferred
167 * @timeout: time in msecs to wait for the message to complete before
168 * timing out (if 0 the wait is forever)
170 * Context: !in_interrupt ()
172 * This function sends a simple interrupt message to a specified endpoint and
173 * waits for the message to complete, or timeout.
175 * If successful, it returns 0, otherwise a negative error number. The number
176 * of actual bytes transferred will be stored in the actual_length paramater.
178 * Don't use this function from within an interrupt context, like a bottom half
179 * handler. If you need an asynchronous message, or need to send a message
180 * from within interrupt context, use usb_submit_urb() If a thread in your
181 * driver uses this call, make sure your disconnect() method can wait for it to
182 * complete. Since you don't have a handle on the URB used, you can't cancel
185 int usb_interrupt_msg(struct usb_device
*usb_dev
, unsigned int pipe
,
186 void *data
, int len
, int *actual_length
, int timeout
)
188 return usb_bulk_msg(usb_dev
, pipe
, data
, len
, actual_length
, timeout
);
190 EXPORT_SYMBOL_GPL(usb_interrupt_msg
);
193 * usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion
194 * @usb_dev: pointer to the usb device to send the message to
195 * @pipe: endpoint "pipe" to send the message to
196 * @data: pointer to the data to send
197 * @len: length in bytes of the data to send
198 * @actual_length: pointer to a location to put the actual length transferred
200 * @timeout: time in msecs to wait for the message to complete before
201 * timing out (if 0 the wait is forever)
203 * Context: !in_interrupt ()
205 * This function sends a simple bulk message to a specified endpoint
206 * and waits for the message to complete, or timeout.
208 * If successful, it returns 0, otherwise a negative error number. The number
209 * of actual bytes transferred will be stored in the actual_length paramater.
211 * Don't use this function from within an interrupt context, like a bottom half
212 * handler. If you need an asynchronous message, or need to send a message
213 * from within interrupt context, use usb_submit_urb() If a thread in your
214 * driver uses this call, make sure your disconnect() method can wait for it to
215 * complete. Since you don't have a handle on the URB used, you can't cancel
218 * Because there is no usb_interrupt_msg() and no USBDEVFS_INTERRUPT ioctl,
219 * users are forced to abuse this routine by using it to submit URBs for
220 * interrupt endpoints. We will take the liberty of creating an interrupt URB
221 * (with the default interval) if the target is an interrupt endpoint.
223 int usb_bulk_msg(struct usb_device
*usb_dev
, unsigned int pipe
,
224 void *data
, int len
, int *actual_length
, int timeout
)
227 struct usb_host_endpoint
*ep
;
229 ep
= (usb_pipein(pipe
) ? usb_dev
->ep_in
: usb_dev
->ep_out
)
230 [usb_pipeendpoint(pipe
)];
234 urb
= usb_alloc_urb(0, GFP_KERNEL
);
238 if ((ep
->desc
.bmAttributes
& USB_ENDPOINT_XFERTYPE_MASK
) ==
239 USB_ENDPOINT_XFER_INT
) {
240 pipe
= (pipe
& ~(3 << 30)) | (PIPE_INTERRUPT
<< 30);
241 usb_fill_int_urb(urb
, usb_dev
, pipe
, data
, len
,
242 usb_api_blocking_completion
, NULL
,
245 usb_fill_bulk_urb(urb
, usb_dev
, pipe
, data
, len
,
246 usb_api_blocking_completion
, NULL
);
248 return usb_start_wait_urb(urb
, timeout
, actual_length
);
250 EXPORT_SYMBOL_GPL(usb_bulk_msg
);
252 /*-------------------------------------------------------------------*/
254 static void sg_clean(struct usb_sg_request
*io
)
257 while (io
->entries
--)
258 usb_free_urb(io
->urbs
[io
->entries
]);
262 if (io
->dev
->dev
.dma_mask
!= NULL
)
263 usb_buffer_unmap_sg(io
->dev
, usb_pipein(io
->pipe
),
268 static void sg_complete(struct urb
*urb
)
270 struct usb_sg_request
*io
= urb
->context
;
271 int status
= urb
->status
;
273 spin_lock(&io
->lock
);
275 /* In 2.5 we require hcds' endpoint queues not to progress after fault
276 * reports, until the completion callback (this!) returns. That lets
277 * device driver code (like this routine) unlink queued urbs first,
278 * if it needs to, since the HC won't work on them at all. So it's
279 * not possible for page N+1 to overwrite page N, and so on.
281 * That's only for "hard" faults; "soft" faults (unlinks) sometimes
282 * complete before the HCD can get requests away from hardware,
283 * though never during cleanup after a hard fault.
286 && (io
->status
!= -ECONNRESET
287 || status
!= -ECONNRESET
)
288 && urb
->actual_length
) {
289 dev_err(io
->dev
->bus
->controller
,
290 "dev %s ep%d%s scatterlist error %d/%d\n",
292 usb_endpoint_num(&urb
->ep
->desc
),
293 usb_urb_dir_in(urb
) ? "in" : "out",
298 if (io
->status
== 0 && status
&& status
!= -ECONNRESET
) {
299 int i
, found
, retval
;
303 /* the previous urbs, and this one, completed already.
304 * unlink pending urbs so they won't rx/tx bad data.
305 * careful: unlink can sometimes be synchronous...
307 spin_unlock(&io
->lock
);
308 for (i
= 0, found
= 0; i
< io
->entries
; i
++) {
309 if (!io
->urbs
[i
] || !io
->urbs
[i
]->dev
)
312 retval
= usb_unlink_urb(io
->urbs
[i
]);
313 if (retval
!= -EINPROGRESS
&&
316 dev_err(&io
->dev
->dev
,
317 "%s, unlink --> %d\n",
319 } else if (urb
== io
->urbs
[i
])
322 spin_lock(&io
->lock
);
326 /* on the last completion, signal usb_sg_wait() */
327 io
->bytes
+= urb
->actual_length
;
330 complete(&io
->complete
);
332 spin_unlock(&io
->lock
);
337 * usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request
338 * @io: request block being initialized. until usb_sg_wait() returns,
339 * treat this as a pointer to an opaque block of memory,
340 * @dev: the usb device that will send or receive the data
341 * @pipe: endpoint "pipe" used to transfer the data
342 * @period: polling rate for interrupt endpoints, in frames or
343 * (for high speed endpoints) microframes; ignored for bulk
344 * @sg: scatterlist entries
345 * @nents: how many entries in the scatterlist
346 * @length: how many bytes to send from the scatterlist, or zero to
347 * send every byte identified in the list.
348 * @mem_flags: SLAB_* flags affecting memory allocations in this call
350 * Returns zero for success, else a negative errno value. This initializes a
351 * scatter/gather request, allocating resources such as I/O mappings and urb
352 * memory (except maybe memory used by USB controller drivers).
354 * The request must be issued using usb_sg_wait(), which waits for the I/O to
355 * complete (or to be canceled) and then cleans up all resources allocated by
358 * The request may be canceled with usb_sg_cancel(), either before or after
359 * usb_sg_wait() is called.
361 int usb_sg_init(struct usb_sg_request
*io
, struct usb_device
*dev
,
362 unsigned pipe
, unsigned period
, struct scatterlist
*sg
,
363 int nents
, size_t length
, gfp_t mem_flags
)
369 if (!io
|| !dev
|| !sg
370 || usb_pipecontrol(pipe
)
371 || usb_pipeisoc(pipe
)
375 spin_lock_init(&io
->lock
);
381 /* not all host controllers use DMA (like the mainstream pci ones);
382 * they can use PIO (sl811) or be software over another transport.
384 dma
= (dev
->dev
.dma_mask
!= NULL
);
386 io
->entries
= usb_buffer_map_sg(dev
, usb_pipein(pipe
),
391 /* initialize all the urbs we'll use */
392 if (io
->entries
<= 0)
395 io
->urbs
= kmalloc(io
->entries
* sizeof *io
->urbs
, mem_flags
);
399 urb_flags
= URB_NO_INTERRUPT
;
401 urb_flags
|= URB_NO_TRANSFER_DMA_MAP
;
402 if (usb_pipein(pipe
))
403 urb_flags
|= URB_SHORT_NOT_OK
;
405 for_each_sg(sg
, sg
, io
->entries
, i
) {
408 io
->urbs
[i
] = usb_alloc_urb(0, mem_flags
);
414 io
->urbs
[i
]->dev
= NULL
;
415 io
->urbs
[i
]->pipe
= pipe
;
416 io
->urbs
[i
]->interval
= period
;
417 io
->urbs
[i
]->transfer_flags
= urb_flags
;
419 io
->urbs
[i
]->complete
= sg_complete
;
420 io
->urbs
[i
]->context
= io
;
423 * Some systems need to revert to PIO when DMA is temporarily
424 * unavailable. For their sakes, both transfer_buffer and
425 * transfer_dma are set when possible. However this can only
426 * work on systems without:
428 * - HIGHMEM, since DMA buffers located in high memory are
429 * not directly addressable by the CPU for PIO;
431 * - IOMMU, since dma_map_sg() is allowed to use an IOMMU to
432 * make virtually discontiguous buffers be "dma-contiguous"
433 * so that PIO and DMA need diferent numbers of URBs.
435 * So when HIGHMEM or IOMMU are in use, transfer_buffer is NULL
436 * to prevent stale pointers and to help spot bugs.
439 io
->urbs
[i
]->transfer_dma
= sg_dma_address(sg
);
440 len
= sg_dma_len(sg
);
441 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_GART_IOMMU)
442 io
->urbs
[i
]->transfer_buffer
= NULL
;
444 io
->urbs
[i
]->transfer_buffer
= sg_virt(sg
);
447 /* hc may use _only_ transfer_buffer */
448 io
->urbs
[i
]->transfer_buffer
= sg_virt(sg
);
453 len
= min_t(unsigned, len
, length
);
458 io
->urbs
[i
]->transfer_buffer_length
= len
;
460 io
->urbs
[--i
]->transfer_flags
&= ~URB_NO_INTERRUPT
;
462 /* transaction state */
463 io
->count
= io
->entries
;
466 init_completion(&io
->complete
);
473 EXPORT_SYMBOL_GPL(usb_sg_init
);
476 * usb_sg_wait - synchronously execute scatter/gather request
477 * @io: request block handle, as initialized with usb_sg_init().
478 * some fields become accessible when this call returns.
479 * Context: !in_interrupt ()
481 * This function blocks until the specified I/O operation completes. It
482 * leverages the grouping of the related I/O requests to get good transfer
483 * rates, by queueing the requests. At higher speeds, such queuing can
484 * significantly improve USB throughput.
486 * There are three kinds of completion for this function.
487 * (1) success, where io->status is zero. The number of io->bytes
488 * transferred is as requested.
489 * (2) error, where io->status is a negative errno value. The number
490 * of io->bytes transferred before the error is usually less
491 * than requested, and can be nonzero.
492 * (3) cancellation, a type of error with status -ECONNRESET that
493 * is initiated by usb_sg_cancel().
495 * When this function returns, all memory allocated through usb_sg_init() or
496 * this call will have been freed. The request block parameter may still be
497 * passed to usb_sg_cancel(), or it may be freed. It could also be
498 * reinitialized and then reused.
500 * Data Transfer Rates:
502 * Bulk transfers are valid for full or high speed endpoints.
503 * The best full speed data rate is 19 packets of 64 bytes each
504 * per frame, or 1216 bytes per millisecond.
505 * The best high speed data rate is 13 packets of 512 bytes each
506 * per microframe, or 52 KBytes per millisecond.
508 * The reason to use interrupt transfers through this API would most likely
509 * be to reserve high speed bandwidth, where up to 24 KBytes per millisecond
510 * could be transferred. That capability is less useful for low or full
511 * speed interrupt endpoints, which allow at most one packet per millisecond,
512 * of at most 8 or 64 bytes (respectively).
514 void usb_sg_wait(struct usb_sg_request
*io
)
517 int entries
= io
->entries
;
519 /* queue the urbs. */
520 spin_lock_irq(&io
->lock
);
522 while (i
< entries
&& !io
->status
) {
525 io
->urbs
[i
]->dev
= io
->dev
;
526 retval
= usb_submit_urb(io
->urbs
[i
], GFP_ATOMIC
);
528 /* after we submit, let completions or cancelations fire;
529 * we handshake using io->status.
531 spin_unlock_irq(&io
->lock
);
533 /* maybe we retrying will recover */
534 case -ENXIO
: /* hc didn't queue this one */
537 io
->urbs
[i
]->dev
= NULL
;
542 /* no error? continue immediately.
544 * NOTE: to work better with UHCI (4K I/O buffer may
545 * need 3K of TDs) it may be good to limit how many
546 * URBs are queued at once; N milliseconds?
553 /* fail any uncompleted urbs */
555 io
->urbs
[i
]->dev
= NULL
;
556 io
->urbs
[i
]->status
= retval
;
557 dev_dbg(&io
->dev
->dev
, "%s, submit --> %d\n",
561 spin_lock_irq(&io
->lock
);
562 if (retval
&& (io
->status
== 0 || io
->status
== -ECONNRESET
))
565 io
->count
-= entries
- i
;
567 complete(&io
->complete
);
568 spin_unlock_irq(&io
->lock
);
570 /* OK, yes, this could be packaged as non-blocking.
571 * So could the submit loop above ... but it's easier to
572 * solve neither problem than to solve both!
574 wait_for_completion(&io
->complete
);
578 EXPORT_SYMBOL_GPL(usb_sg_wait
);
581 * usb_sg_cancel - stop scatter/gather i/o issued by usb_sg_wait()
582 * @io: request block, initialized with usb_sg_init()
584 * This stops a request after it has been started by usb_sg_wait().
585 * It can also prevents one initialized by usb_sg_init() from starting,
586 * so that call just frees resources allocated to the request.
588 void usb_sg_cancel(struct usb_sg_request
*io
)
592 spin_lock_irqsave(&io
->lock
, flags
);
594 /* shut everything down, if it didn't already */
598 io
->status
= -ECONNRESET
;
599 spin_unlock(&io
->lock
);
600 for (i
= 0; i
< io
->entries
; i
++) {
603 if (!io
->urbs
[i
]->dev
)
605 retval
= usb_unlink_urb(io
->urbs
[i
]);
606 if (retval
!= -EINPROGRESS
&& retval
!= -EBUSY
)
607 dev_warn(&io
->dev
->dev
, "%s, unlink --> %d\n",
610 spin_lock(&io
->lock
);
612 spin_unlock_irqrestore(&io
->lock
, flags
);
614 EXPORT_SYMBOL_GPL(usb_sg_cancel
);
616 /*-------------------------------------------------------------------*/
619 * usb_get_descriptor - issues a generic GET_DESCRIPTOR request
620 * @dev: the device whose descriptor is being retrieved
621 * @type: the descriptor type (USB_DT_*)
622 * @index: the number of the descriptor
623 * @buf: where to put the descriptor
624 * @size: how big is "buf"?
625 * Context: !in_interrupt ()
627 * Gets a USB descriptor. Convenience functions exist to simplify
628 * getting some types of descriptors. Use
629 * usb_get_string() or usb_string() for USB_DT_STRING.
630 * Device (USB_DT_DEVICE) and configuration descriptors (USB_DT_CONFIG)
631 * are part of the device structure.
632 * In addition to a number of USB-standard descriptors, some
633 * devices also use class-specific or vendor-specific descriptors.
635 * This call is synchronous, and may not be used in an interrupt context.
637 * Returns the number of bytes received on success, or else the status code
638 * returned by the underlying usb_control_msg() call.
640 int usb_get_descriptor(struct usb_device
*dev
, unsigned char type
,
641 unsigned char index
, void *buf
, int size
)
646 memset(buf
, 0, size
); /* Make sure we parse really received data */
648 for (i
= 0; i
< 3; ++i
) {
649 /* retry on length 0 or error; some devices are flakey */
650 result
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0),
651 USB_REQ_GET_DESCRIPTOR
, USB_DIR_IN
,
652 (type
<< 8) + index
, 0, buf
, size
,
653 USB_CTRL_GET_TIMEOUT
);
654 if (result
<= 0 && result
!= -ETIMEDOUT
)
656 if (result
> 1 && ((u8
*)buf
)[1] != type
) {
664 EXPORT_SYMBOL_GPL(usb_get_descriptor
);
667 * usb_get_string - gets a string descriptor
668 * @dev: the device whose string descriptor is being retrieved
669 * @langid: code for language chosen (from string descriptor zero)
670 * @index: the number of the descriptor
671 * @buf: where to put the string
672 * @size: how big is "buf"?
673 * Context: !in_interrupt ()
675 * Retrieves a string, encoded using UTF-16LE (Unicode, 16 bits per character,
676 * in little-endian byte order).
677 * The usb_string() function will often be a convenient way to turn
678 * these strings into kernel-printable form.
680 * Strings may be referenced in device, configuration, interface, or other
681 * descriptors, and could also be used in vendor-specific ways.
683 * This call is synchronous, and may not be used in an interrupt context.
685 * Returns the number of bytes received on success, or else the status code
686 * returned by the underlying usb_control_msg() call.
688 static int usb_get_string(struct usb_device
*dev
, unsigned short langid
,
689 unsigned char index
, void *buf
, int size
)
694 for (i
= 0; i
< 3; ++i
) {
695 /* retry on length 0 or stall; some devices are flakey */
696 result
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0),
697 USB_REQ_GET_DESCRIPTOR
, USB_DIR_IN
,
698 (USB_DT_STRING
<< 8) + index
, langid
, buf
, size
,
699 USB_CTRL_GET_TIMEOUT
);
700 if (result
== 0 || result
== -EPIPE
)
702 if (result
> 1 && ((u8
*) buf
)[1] != USB_DT_STRING
) {
711 static void usb_try_string_workarounds(unsigned char *buf
, int *length
)
713 int newlength
, oldlength
= *length
;
715 for (newlength
= 2; newlength
+ 1 < oldlength
; newlength
+= 2)
716 if (!isprint(buf
[newlength
]) || buf
[newlength
+ 1])
725 static int usb_string_sub(struct usb_device
*dev
, unsigned int langid
,
726 unsigned int index
, unsigned char *buf
)
730 /* Try to read the string descriptor by asking for the maximum
731 * possible number of bytes */
732 if (dev
->quirks
& USB_QUIRK_STRING_FETCH_255
)
735 rc
= usb_get_string(dev
, langid
, index
, buf
, 255);
737 /* If that failed try to read the descriptor length, then
738 * ask for just that many bytes */
740 rc
= usb_get_string(dev
, langid
, index
, buf
, 2);
742 rc
= usb_get_string(dev
, langid
, index
, buf
, buf
[0]);
746 if (!buf
[0] && !buf
[1])
747 usb_try_string_workarounds(buf
, &rc
);
749 /* There might be extra junk at the end of the descriptor */
753 rc
= rc
- (rc
& 1); /* force a multiple of two */
757 rc
= (rc
< 0 ? rc
: -EINVAL
);
763 * usb_string - returns UTF-8 version of a string descriptor
764 * @dev: the device whose string descriptor is being retrieved
765 * @index: the number of the descriptor
766 * @buf: where to put the string
767 * @size: how big is "buf"?
768 * Context: !in_interrupt ()
770 * This converts the UTF-16LE encoded strings returned by devices, from
771 * usb_get_string_descriptor(), to null-terminated UTF-8 encoded ones
772 * that are more usable in most kernel contexts. Note that this function
773 * chooses strings in the first language supported by the device.
775 * This call is synchronous, and may not be used in an interrupt context.
777 * Returns length of the string (>= 0) or usb_control_msg status (< 0).
779 int usb_string(struct usb_device
*dev
, int index
, char *buf
, size_t size
)
784 if (dev
->state
== USB_STATE_SUSPENDED
)
785 return -EHOSTUNREACH
;
786 if (size
<= 0 || !buf
|| !index
)
789 tbuf
= kmalloc(256, GFP_NOIO
);
793 /* get langid for strings if it's not yet known */
794 if (!dev
->have_langid
) {
795 err
= usb_string_sub(dev
, 0, 0, tbuf
);
798 "string descriptor 0 read error: %d\n",
800 } else if (err
< 4) {
801 dev_err(&dev
->dev
, "string descriptor 0 too short\n");
803 dev
->string_langid
= tbuf
[2] | (tbuf
[3] << 8);
804 /* always use the first langid listed */
805 dev_dbg(&dev
->dev
, "default language 0x%04x\n",
809 dev
->have_langid
= 1;
812 err
= usb_string_sub(dev
, dev
->string_langid
, index
, tbuf
);
816 size
--; /* leave room for trailing NULL char in output buffer */
817 err
= utf16s_to_utf8s((wchar_t *) &tbuf
[2], (err
- 2) / 2,
818 UTF16_LITTLE_ENDIAN
, buf
, size
);
821 if (tbuf
[1] != USB_DT_STRING
)
823 "wrong descriptor type %02x for string %d (\"%s\")\n",
824 tbuf
[1], index
, buf
);
830 EXPORT_SYMBOL_GPL(usb_string
);
832 /* one UTF-8-encoded 16-bit character has at most three bytes */
833 #define MAX_USB_STRING_SIZE (127 * 3 + 1)
836 * usb_cache_string - read a string descriptor and cache it for later use
837 * @udev: the device whose string descriptor is being read
838 * @index: the descriptor index
840 * Returns a pointer to a kmalloc'ed buffer containing the descriptor string,
841 * or NULL if the index is 0 or the string could not be read.
843 char *usb_cache_string(struct usb_device
*udev
, int index
)
846 char *smallbuf
= NULL
;
852 buf
= kmalloc(MAX_USB_STRING_SIZE
, GFP_KERNEL
);
854 len
= usb_string(udev
, index
, buf
, MAX_USB_STRING_SIZE
);
856 smallbuf
= kmalloc(++len
, GFP_KERNEL
);
859 memcpy(smallbuf
, buf
, len
);
867 * usb_get_device_descriptor - (re)reads the device descriptor (usbcore)
868 * @dev: the device whose device descriptor is being updated
869 * @size: how much of the descriptor to read
870 * Context: !in_interrupt ()
872 * Updates the copy of the device descriptor stored in the device structure,
873 * which dedicates space for this purpose.
875 * Not exported, only for use by the core. If drivers really want to read
876 * the device descriptor directly, they can call usb_get_descriptor() with
877 * type = USB_DT_DEVICE and index = 0.
879 * This call is synchronous, and may not be used in an interrupt context.
881 * Returns the number of bytes received on success, or else the status code
882 * returned by the underlying usb_control_msg() call.
884 int usb_get_device_descriptor(struct usb_device
*dev
, unsigned int size
)
886 struct usb_device_descriptor
*desc
;
889 if (size
> sizeof(*desc
))
891 desc
= kmalloc(sizeof(*desc
), GFP_NOIO
);
895 ret
= usb_get_descriptor(dev
, USB_DT_DEVICE
, 0, desc
, size
);
897 memcpy(&dev
->descriptor
, desc
, size
);
903 * usb_get_status - issues a GET_STATUS call
904 * @dev: the device whose status is being checked
905 * @type: USB_RECIP_*; for device, interface, or endpoint
906 * @target: zero (for device), else interface or endpoint number
907 * @data: pointer to two bytes of bitmap data
908 * Context: !in_interrupt ()
910 * Returns device, interface, or endpoint status. Normally only of
911 * interest to see if the device is self powered, or has enabled the
912 * remote wakeup facility; or whether a bulk or interrupt endpoint
913 * is halted ("stalled").
915 * Bits in these status bitmaps are set using the SET_FEATURE request,
916 * and cleared using the CLEAR_FEATURE request. The usb_clear_halt()
917 * function should be used to clear halt ("stall") status.
919 * This call is synchronous, and may not be used in an interrupt context.
921 * Returns the number of bytes received on success, or else the status code
922 * returned by the underlying usb_control_msg() call.
924 int usb_get_status(struct usb_device
*dev
, int type
, int target
, void *data
)
927 u16
*status
= kmalloc(sizeof(*status
), GFP_KERNEL
);
932 ret
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0),
933 USB_REQ_GET_STATUS
, USB_DIR_IN
| type
, 0, target
, status
,
934 sizeof(*status
), USB_CTRL_GET_TIMEOUT
);
936 *(u16
*)data
= *status
;
940 EXPORT_SYMBOL_GPL(usb_get_status
);
943 * usb_clear_halt - tells device to clear endpoint halt/stall condition
944 * @dev: device whose endpoint is halted
945 * @pipe: endpoint "pipe" being cleared
946 * Context: !in_interrupt ()
948 * This is used to clear halt conditions for bulk and interrupt endpoints,
949 * as reported by URB completion status. Endpoints that are halted are
950 * sometimes referred to as being "stalled". Such endpoints are unable
951 * to transmit or receive data until the halt status is cleared. Any URBs
952 * queued for such an endpoint should normally be unlinked by the driver
953 * before clearing the halt condition, as described in sections 5.7.5
954 * and 5.8.5 of the USB 2.0 spec.
956 * Note that control and isochronous endpoints don't halt, although control
957 * endpoints report "protocol stall" (for unsupported requests) using the
958 * same status code used to report a true stall.
960 * This call is synchronous, and may not be used in an interrupt context.
962 * Returns zero on success, or else the status code returned by the
963 * underlying usb_control_msg() call.
965 int usb_clear_halt(struct usb_device
*dev
, int pipe
)
968 int endp
= usb_pipeendpoint(pipe
);
970 if (usb_pipein(pipe
))
973 /* we don't care if it wasn't halted first. in fact some devices
974 * (like some ibmcam model 1 units) seem to expect hosts to make
975 * this request for iso endpoints, which can't halt!
977 result
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
978 USB_REQ_CLEAR_FEATURE
, USB_RECIP_ENDPOINT
,
979 USB_ENDPOINT_HALT
, endp
, NULL
, 0,
980 USB_CTRL_SET_TIMEOUT
);
982 /* don't un-halt or force to DATA0 except on success */
986 /* NOTE: seems like Microsoft and Apple don't bother verifying
987 * the clear "took", so some devices could lock up if you check...
988 * such as the Hagiwara FlashGate DUAL. So we won't bother.
990 * NOTE: make sure the logic here doesn't diverge much from
991 * the copy in usb-storage, for as long as we need two copies.
994 usb_reset_endpoint(dev
, endp
);
998 EXPORT_SYMBOL_GPL(usb_clear_halt
);
1000 static int create_intf_ep_devs(struct usb_interface
*intf
)
1002 struct usb_device
*udev
= interface_to_usbdev(intf
);
1003 struct usb_host_interface
*alt
= intf
->cur_altsetting
;
1006 if (intf
->ep_devs_created
|| intf
->unregistering
)
1009 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; ++i
)
1010 (void) usb_create_ep_devs(&intf
->dev
, &alt
->endpoint
[i
], udev
);
1011 intf
->ep_devs_created
= 1;
1015 static void remove_intf_ep_devs(struct usb_interface
*intf
)
1017 struct usb_host_interface
*alt
= intf
->cur_altsetting
;
1020 if (!intf
->ep_devs_created
)
1023 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; ++i
)
1024 usb_remove_ep_devs(&alt
->endpoint
[i
]);
1025 intf
->ep_devs_created
= 0;
1029 * usb_disable_endpoint -- Disable an endpoint by address
1030 * @dev: the device whose endpoint is being disabled
1031 * @epaddr: the endpoint's address. Endpoint number for output,
1032 * endpoint number + USB_DIR_IN for input
1033 * @reset_hardware: flag to erase any endpoint state stored in the
1034 * controller hardware
1036 * Disables the endpoint for URB submission and nukes all pending URBs.
1037 * If @reset_hardware is set then also deallocates hcd/hardware state
1040 void usb_disable_endpoint(struct usb_device
*dev
, unsigned int epaddr
,
1041 bool reset_hardware
)
1043 unsigned int epnum
= epaddr
& USB_ENDPOINT_NUMBER_MASK
;
1044 struct usb_host_endpoint
*ep
;
1049 if (usb_endpoint_out(epaddr
)) {
1050 ep
= dev
->ep_out
[epnum
];
1052 dev
->ep_out
[epnum
] = NULL
;
1054 ep
= dev
->ep_in
[epnum
];
1056 dev
->ep_in
[epnum
] = NULL
;
1060 usb_hcd_flush_endpoint(dev
, ep
);
1062 usb_hcd_disable_endpoint(dev
, ep
);
1067 * usb_reset_endpoint - Reset an endpoint's state.
1068 * @dev: the device whose endpoint is to be reset
1069 * @epaddr: the endpoint's address. Endpoint number for output,
1070 * endpoint number + USB_DIR_IN for input
1072 * Resets any host-side endpoint state such as the toggle bit,
1073 * sequence number or current window.
1075 void usb_reset_endpoint(struct usb_device
*dev
, unsigned int epaddr
)
1077 unsigned int epnum
= epaddr
& USB_ENDPOINT_NUMBER_MASK
;
1078 struct usb_host_endpoint
*ep
;
1080 if (usb_endpoint_out(epaddr
))
1081 ep
= dev
->ep_out
[epnum
];
1083 ep
= dev
->ep_in
[epnum
];
1085 usb_hcd_reset_endpoint(dev
, ep
);
1087 EXPORT_SYMBOL_GPL(usb_reset_endpoint
);
1091 * usb_disable_interface -- Disable all endpoints for an interface
1092 * @dev: the device whose interface is being disabled
1093 * @intf: pointer to the interface descriptor
1094 * @reset_hardware: flag to erase any endpoint state stored in the
1095 * controller hardware
1097 * Disables all the endpoints for the interface's current altsetting.
1099 void usb_disable_interface(struct usb_device
*dev
, struct usb_interface
*intf
,
1100 bool reset_hardware
)
1102 struct usb_host_interface
*alt
= intf
->cur_altsetting
;
1105 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; ++i
) {
1106 usb_disable_endpoint(dev
,
1107 alt
->endpoint
[i
].desc
.bEndpointAddress
,
1113 * usb_disable_device - Disable all the endpoints for a USB device
1114 * @dev: the device whose endpoints are being disabled
1115 * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
1117 * Disables all the device's endpoints, potentially including endpoint 0.
1118 * Deallocates hcd/hardware state for the endpoints (nuking all or most
1119 * pending urbs) and usbcore state for the interfaces, so that usbcore
1120 * must usb_set_configuration() before any interfaces could be used.
1122 void usb_disable_device(struct usb_device
*dev
, int skip_ep0
)
1126 dev_dbg(&dev
->dev
, "%s nuking %s URBs\n", __func__
,
1127 skip_ep0
? "non-ep0" : "all");
1128 for (i
= skip_ep0
; i
< 16; ++i
) {
1129 usb_disable_endpoint(dev
, i
, true);
1130 usb_disable_endpoint(dev
, i
+ USB_DIR_IN
, true);
1133 /* getting rid of interfaces will disconnect
1134 * any drivers bound to them (a key side effect)
1136 if (dev
->actconfig
) {
1137 for (i
= 0; i
< dev
->actconfig
->desc
.bNumInterfaces
; i
++) {
1138 struct usb_interface
*interface
;
1140 /* remove this interface if it has been registered */
1141 interface
= dev
->actconfig
->interface
[i
];
1142 if (!device_is_registered(&interface
->dev
))
1144 dev_dbg(&dev
->dev
, "unregistering interface %s\n",
1145 dev_name(&interface
->dev
));
1146 interface
->unregistering
= 1;
1147 remove_intf_ep_devs(interface
);
1148 device_del(&interface
->dev
);
1151 /* Now that the interfaces are unbound, nobody should
1152 * try to access them.
1154 for (i
= 0; i
< dev
->actconfig
->desc
.bNumInterfaces
; i
++) {
1155 put_device(&dev
->actconfig
->interface
[i
]->dev
);
1156 dev
->actconfig
->interface
[i
] = NULL
;
1158 dev
->actconfig
= NULL
;
1159 if (dev
->state
== USB_STATE_CONFIGURED
)
1160 usb_set_device_state(dev
, USB_STATE_ADDRESS
);
1165 * usb_enable_endpoint - Enable an endpoint for USB communications
1166 * @dev: the device whose interface is being enabled
1168 * @reset_ep: flag to reset the endpoint state
1170 * Resets the endpoint state if asked, and sets dev->ep_{in,out} pointers.
1171 * For control endpoints, both the input and output sides are handled.
1173 void usb_enable_endpoint(struct usb_device
*dev
, struct usb_host_endpoint
*ep
,
1176 int epnum
= usb_endpoint_num(&ep
->desc
);
1177 int is_out
= usb_endpoint_dir_out(&ep
->desc
);
1178 int is_control
= usb_endpoint_xfer_control(&ep
->desc
);
1181 usb_hcd_reset_endpoint(dev
, ep
);
1182 if (is_out
|| is_control
)
1183 dev
->ep_out
[epnum
] = ep
;
1184 if (!is_out
|| is_control
)
1185 dev
->ep_in
[epnum
] = ep
;
1190 * usb_enable_interface - Enable all the endpoints for an interface
1191 * @dev: the device whose interface is being enabled
1192 * @intf: pointer to the interface descriptor
1193 * @reset_eps: flag to reset the endpoints' state
1195 * Enables all the endpoints for the interface's current altsetting.
1197 void usb_enable_interface(struct usb_device
*dev
,
1198 struct usb_interface
*intf
, bool reset_eps
)
1200 struct usb_host_interface
*alt
= intf
->cur_altsetting
;
1203 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; ++i
)
1204 usb_enable_endpoint(dev
, &alt
->endpoint
[i
], reset_eps
);
1208 * usb_set_interface - Makes a particular alternate setting be current
1209 * @dev: the device whose interface is being updated
1210 * @interface: the interface being updated
1211 * @alternate: the setting being chosen.
1212 * Context: !in_interrupt ()
1214 * This is used to enable data transfers on interfaces that may not
1215 * be enabled by default. Not all devices support such configurability.
1216 * Only the driver bound to an interface may change its setting.
1218 * Within any given configuration, each interface may have several
1219 * alternative settings. These are often used to control levels of
1220 * bandwidth consumption. For example, the default setting for a high
1221 * speed interrupt endpoint may not send more than 64 bytes per microframe,
1222 * while interrupt transfers of up to 3KBytes per microframe are legal.
1223 * Also, isochronous endpoints may never be part of an
1224 * interface's default setting. To access such bandwidth, alternate
1225 * interface settings must be made current.
1227 * Note that in the Linux USB subsystem, bandwidth associated with
1228 * an endpoint in a given alternate setting is not reserved until an URB
1229 * is submitted that needs that bandwidth. Some other operating systems
1230 * allocate bandwidth early, when a configuration is chosen.
1232 * This call is synchronous, and may not be used in an interrupt context.
1233 * Also, drivers must not change altsettings while urbs are scheduled for
1234 * endpoints in that interface; all such urbs must first be completed
1235 * (perhaps forced by unlinking).
1237 * Returns zero on success, or else the status code returned by the
1238 * underlying usb_control_msg() call.
1240 int usb_set_interface(struct usb_device
*dev
, int interface
, int alternate
)
1242 struct usb_interface
*iface
;
1243 struct usb_host_interface
*alt
;
1246 unsigned int epaddr
;
1249 if (dev
->state
== USB_STATE_SUSPENDED
)
1250 return -EHOSTUNREACH
;
1252 iface
= usb_ifnum_to_if(dev
, interface
);
1254 dev_dbg(&dev
->dev
, "selecting invalid interface %d\n",
1259 alt
= usb_altnum_to_altsetting(iface
, alternate
);
1261 dev_warn(&dev
->dev
, "selecting invalid altsetting %d",
1266 if (dev
->quirks
& USB_QUIRK_NO_SET_INTF
)
1269 ret
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
1270 USB_REQ_SET_INTERFACE
, USB_RECIP_INTERFACE
,
1271 alternate
, interface
, NULL
, 0, 5000);
1273 /* 9.4.10 says devices don't need this and are free to STALL the
1274 * request if the interface only has one alternate setting.
1276 if (ret
== -EPIPE
&& iface
->num_altsetting
== 1) {
1278 "manual set_interface for iface %d, alt %d\n",
1279 interface
, alternate
);
1284 /* FIXME drivers shouldn't need to replicate/bugfix the logic here
1285 * when they implement async or easily-killable versions of this or
1286 * other "should-be-internal" functions (like clear_halt).
1287 * should hcd+usbcore postprocess control requests?
1290 /* prevent submissions using previous endpoint settings */
1291 if (iface
->cur_altsetting
!= alt
) {
1292 remove_intf_ep_devs(iface
);
1293 usb_remove_sysfs_intf_files(iface
);
1295 usb_disable_interface(dev
, iface
, true);
1297 iface
->cur_altsetting
= alt
;
1299 /* If the interface only has one altsetting and the device didn't
1300 * accept the request, we attempt to carry out the equivalent action
1301 * by manually clearing the HALT feature for each endpoint in the
1307 for (i
= 0; i
< alt
->desc
.bNumEndpoints
; i
++) {
1308 epaddr
= alt
->endpoint
[i
].desc
.bEndpointAddress
;
1309 pipe
= __create_pipe(dev
,
1310 USB_ENDPOINT_NUMBER_MASK
& epaddr
) |
1311 (usb_endpoint_out(epaddr
) ?
1312 USB_DIR_OUT
: USB_DIR_IN
);
1314 usb_clear_halt(dev
, pipe
);
1318 /* 9.1.1.5: reset toggles for all endpoints in the new altsetting
1321 * Despite EP0 is always present in all interfaces/AS, the list of
1322 * endpoints from the descriptor does not contain EP0. Due to its
1323 * omnipresence one might expect EP0 being considered "affected" by
1324 * any SetInterface request and hence assume toggles need to be reset.
1325 * However, EP0 toggles are re-synced for every individual transfer
1326 * during the SETUP stage - hence EP0 toggles are "don't care" here.
1327 * (Likewise, EP0 never "halts" on well designed devices.)
1329 usb_enable_interface(dev
, iface
, true);
1330 if (device_is_registered(&iface
->dev
)) {
1331 usb_create_sysfs_intf_files(iface
);
1332 create_intf_ep_devs(iface
);
1336 EXPORT_SYMBOL_GPL(usb_set_interface
);
1339 * usb_reset_configuration - lightweight device reset
1340 * @dev: the device whose configuration is being reset
1342 * This issues a standard SET_CONFIGURATION request to the device using
1343 * the current configuration. The effect is to reset most USB-related
1344 * state in the device, including interface altsettings (reset to zero),
1345 * endpoint halts (cleared), and endpoint state (only for bulk and interrupt
1346 * endpoints). Other usbcore state is unchanged, including bindings of
1347 * usb device drivers to interfaces.
1349 * Because this affects multiple interfaces, avoid using this with composite
1350 * (multi-interface) devices. Instead, the driver for each interface may
1351 * use usb_set_interface() on the interfaces it claims. Be careful though;
1352 * some devices don't support the SET_INTERFACE request, and others won't
1353 * reset all the interface state (notably endpoint state). Resetting the whole
1354 * configuration would affect other drivers' interfaces.
1356 * The caller must own the device lock.
1358 * Returns zero on success, else a negative error code.
1360 int usb_reset_configuration(struct usb_device
*dev
)
1363 struct usb_host_config
*config
;
1365 if (dev
->state
== USB_STATE_SUSPENDED
)
1366 return -EHOSTUNREACH
;
1368 /* caller must have locked the device and must own
1369 * the usb bus readlock (so driver bindings are stable);
1370 * calls during probe() are fine
1373 for (i
= 1; i
< 16; ++i
) {
1374 usb_disable_endpoint(dev
, i
, true);
1375 usb_disable_endpoint(dev
, i
+ USB_DIR_IN
, true);
1378 config
= dev
->actconfig
;
1379 retval
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
1380 USB_REQ_SET_CONFIGURATION
, 0,
1381 config
->desc
.bConfigurationValue
, 0,
1382 NULL
, 0, USB_CTRL_SET_TIMEOUT
);
1386 /* re-init hc/hcd interface/endpoint state */
1387 for (i
= 0; i
< config
->desc
.bNumInterfaces
; i
++) {
1388 struct usb_interface
*intf
= config
->interface
[i
];
1389 struct usb_host_interface
*alt
;
1391 alt
= usb_altnum_to_altsetting(intf
, 0);
1393 /* No altsetting 0? We'll assume the first altsetting.
1394 * We could use a GetInterface call, but if a device is
1395 * so non-compliant that it doesn't have altsetting 0
1396 * then I wouldn't trust its reply anyway.
1399 alt
= &intf
->altsetting
[0];
1401 if (alt
!= intf
->cur_altsetting
) {
1402 remove_intf_ep_devs(intf
);
1403 usb_remove_sysfs_intf_files(intf
);
1405 intf
->cur_altsetting
= alt
;
1406 usb_enable_interface(dev
, intf
, true);
1407 if (device_is_registered(&intf
->dev
)) {
1408 usb_create_sysfs_intf_files(intf
);
1409 create_intf_ep_devs(intf
);
1414 EXPORT_SYMBOL_GPL(usb_reset_configuration
);
1416 static void usb_release_interface(struct device
*dev
)
1418 struct usb_interface
*intf
= to_usb_interface(dev
);
1419 struct usb_interface_cache
*intfc
=
1420 altsetting_to_usb_interface_cache(intf
->altsetting
);
1422 kref_put(&intfc
->ref
, usb_release_interface_cache
);
1426 #ifdef CONFIG_HOTPLUG
1427 static int usb_if_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
1429 struct usb_device
*usb_dev
;
1430 struct usb_interface
*intf
;
1431 struct usb_host_interface
*alt
;
1433 intf
= to_usb_interface(dev
);
1434 usb_dev
= interface_to_usbdev(intf
);
1435 alt
= intf
->cur_altsetting
;
1437 if (add_uevent_var(env
, "INTERFACE=%d/%d/%d",
1438 alt
->desc
.bInterfaceClass
,
1439 alt
->desc
.bInterfaceSubClass
,
1440 alt
->desc
.bInterfaceProtocol
))
1443 if (add_uevent_var(env
,
1445 "v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02X",
1446 le16_to_cpu(usb_dev
->descriptor
.idVendor
),
1447 le16_to_cpu(usb_dev
->descriptor
.idProduct
),
1448 le16_to_cpu(usb_dev
->descriptor
.bcdDevice
),
1449 usb_dev
->descriptor
.bDeviceClass
,
1450 usb_dev
->descriptor
.bDeviceSubClass
,
1451 usb_dev
->descriptor
.bDeviceProtocol
,
1452 alt
->desc
.bInterfaceClass
,
1453 alt
->desc
.bInterfaceSubClass
,
1454 alt
->desc
.bInterfaceProtocol
))
1462 static int usb_if_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
1466 #endif /* CONFIG_HOTPLUG */
1468 struct device_type usb_if_device_type
= {
1469 .name
= "usb_interface",
1470 .release
= usb_release_interface
,
1471 .uevent
= usb_if_uevent
,
1474 static struct usb_interface_assoc_descriptor
*find_iad(struct usb_device
*dev
,
1475 struct usb_host_config
*config
,
1478 struct usb_interface_assoc_descriptor
*retval
= NULL
;
1479 struct usb_interface_assoc_descriptor
*intf_assoc
;
1484 for (i
= 0; (i
< USB_MAXIADS
&& config
->intf_assoc
[i
]); i
++) {
1485 intf_assoc
= config
->intf_assoc
[i
];
1486 if (intf_assoc
->bInterfaceCount
== 0)
1489 first_intf
= intf_assoc
->bFirstInterface
;
1490 last_intf
= first_intf
+ (intf_assoc
->bInterfaceCount
- 1);
1491 if (inum
>= first_intf
&& inum
<= last_intf
) {
1493 retval
= intf_assoc
;
1495 dev_err(&dev
->dev
, "Interface #%d referenced"
1496 " by multiple IADs\n", inum
);
1505 * Internal function to queue a device reset
1507 * This is initialized into the workstruct in 'struct
1508 * usb_device->reset_ws' that is launched by
1509 * message.c:usb_set_configuration() when initializing each 'struct
1512 * It is safe to get the USB device without reference counts because
1513 * the life cycle of @iface is bound to the life cycle of @udev. Then,
1514 * this function will be ran only if @iface is alive (and before
1515 * freeing it any scheduled instances of it will have been cancelled).
1517 * We need to set a flag (usb_dev->reset_running) because when we call
1518 * the reset, the interfaces might be unbound. The current interface
1519 * cannot try to remove the queued work as it would cause a deadlock
1520 * (you cannot remove your work from within your executing
1521 * workqueue). This flag lets it know, so that
1522 * usb_cancel_queued_reset() doesn't try to do it.
1524 * See usb_queue_reset_device() for more details
1526 void __usb_queue_reset_device(struct work_struct
*ws
)
1529 struct usb_interface
*iface
=
1530 container_of(ws
, struct usb_interface
, reset_ws
);
1531 struct usb_device
*udev
= interface_to_usbdev(iface
);
1533 rc
= usb_lock_device_for_reset(udev
, iface
);
1535 iface
->reset_running
= 1;
1536 usb_reset_device(udev
);
1537 iface
->reset_running
= 0;
1538 usb_unlock_device(udev
);
1544 * usb_set_configuration - Makes a particular device setting be current
1545 * @dev: the device whose configuration is being updated
1546 * @configuration: the configuration being chosen.
1547 * Context: !in_interrupt(), caller owns the device lock
1549 * This is used to enable non-default device modes. Not all devices
1550 * use this kind of configurability; many devices only have one
1553 * @configuration is the value of the configuration to be installed.
1554 * According to the USB spec (e.g. section 9.1.1.5), configuration values
1555 * must be non-zero; a value of zero indicates that the device in
1556 * unconfigured. However some devices erroneously use 0 as one of their
1557 * configuration values. To help manage such devices, this routine will
1558 * accept @configuration = -1 as indicating the device should be put in
1559 * an unconfigured state.
1561 * USB device configurations may affect Linux interoperability,
1562 * power consumption and the functionality available. For example,
1563 * the default configuration is limited to using 100mA of bus power,
1564 * so that when certain device functionality requires more power,
1565 * and the device is bus powered, that functionality should be in some
1566 * non-default device configuration. Other device modes may also be
1567 * reflected as configuration options, such as whether two ISDN
1568 * channels are available independently; and choosing between open
1569 * standard device protocols (like CDC) or proprietary ones.
1571 * Note that a non-authorized device (dev->authorized == 0) will only
1572 * be put in unconfigured mode.
1574 * Note that USB has an additional level of device configurability,
1575 * associated with interfaces. That configurability is accessed using
1576 * usb_set_interface().
1578 * This call is synchronous. The calling context must be able to sleep,
1579 * must own the device lock, and must not hold the driver model's USB
1580 * bus mutex; usb interface driver probe() methods cannot use this routine.
1582 * Returns zero on success, or else the status code returned by the
1583 * underlying call that failed. On successful completion, each interface
1584 * in the original device configuration has been destroyed, and each one
1585 * in the new configuration has been probed by all relevant usb device
1586 * drivers currently known to the kernel.
1588 int usb_set_configuration(struct usb_device
*dev
, int configuration
)
1591 struct usb_host_config
*cp
= NULL
;
1592 struct usb_interface
**new_interfaces
= NULL
;
1595 if (dev
->authorized
== 0 || configuration
== -1)
1598 for (i
= 0; i
< dev
->descriptor
.bNumConfigurations
; i
++) {
1599 if (dev
->config
[i
].desc
.bConfigurationValue
==
1601 cp
= &dev
->config
[i
];
1606 if ((!cp
&& configuration
!= 0))
1609 /* The USB spec says configuration 0 means unconfigured.
1610 * But if a device includes a configuration numbered 0,
1611 * we will accept it as a correctly configured state.
1612 * Use -1 if you really want to unconfigure the device.
1614 if (cp
&& configuration
== 0)
1615 dev_warn(&dev
->dev
, "config 0 descriptor??\n");
1617 /* Allocate memory for new interfaces before doing anything else,
1618 * so that if we run out then nothing will have changed. */
1621 nintf
= cp
->desc
.bNumInterfaces
;
1622 new_interfaces
= kmalloc(nintf
* sizeof(*new_interfaces
),
1624 if (!new_interfaces
) {
1625 dev_err(&dev
->dev
, "Out of memory\n");
1629 for (; n
< nintf
; ++n
) {
1630 new_interfaces
[n
] = kzalloc(
1631 sizeof(struct usb_interface
),
1633 if (!new_interfaces
[n
]) {
1634 dev_err(&dev
->dev
, "Out of memory\n");
1638 kfree(new_interfaces
[n
]);
1639 kfree(new_interfaces
);
1644 i
= dev
->bus_mA
- cp
->desc
.bMaxPower
* 2;
1646 dev_warn(&dev
->dev
, "new config #%d exceeds power "
1651 /* Wake up the device so we can send it the Set-Config request */
1652 ret
= usb_autoresume_device(dev
);
1654 goto free_interfaces
;
1656 /* if it's already configured, clear out old state first.
1657 * getting rid of old interfaces means unbinding their drivers.
1659 if (dev
->state
!= USB_STATE_ADDRESS
)
1660 usb_disable_device(dev
, 1); /* Skip ep0 */
1662 /* Get rid of pending async Set-Config requests for this device */
1663 cancel_async_set_config(dev
);
1665 ret
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0),
1666 USB_REQ_SET_CONFIGURATION
, 0, configuration
, 0,
1667 NULL
, 0, USB_CTRL_SET_TIMEOUT
);
1669 /* All the old state is gone, so what else can we do?
1670 * The device is probably useless now anyway.
1675 dev
->actconfig
= cp
;
1677 usb_set_device_state(dev
, USB_STATE_ADDRESS
);
1678 usb_autosuspend_device(dev
);
1679 goto free_interfaces
;
1681 usb_set_device_state(dev
, USB_STATE_CONFIGURED
);
1683 /* Initialize the new interface structures and the
1684 * hc/hcd/usbcore interface/endpoint state.
1686 for (i
= 0; i
< nintf
; ++i
) {
1687 struct usb_interface_cache
*intfc
;
1688 struct usb_interface
*intf
;
1689 struct usb_host_interface
*alt
;
1691 cp
->interface
[i
] = intf
= new_interfaces
[i
];
1692 intfc
= cp
->intf_cache
[i
];
1693 intf
->altsetting
= intfc
->altsetting
;
1694 intf
->num_altsetting
= intfc
->num_altsetting
;
1695 intf
->intf_assoc
= find_iad(dev
, cp
, i
);
1696 kref_get(&intfc
->ref
);
1698 alt
= usb_altnum_to_altsetting(intf
, 0);
1700 /* No altsetting 0? We'll assume the first altsetting.
1701 * We could use a GetInterface call, but if a device is
1702 * so non-compliant that it doesn't have altsetting 0
1703 * then I wouldn't trust its reply anyway.
1706 alt
= &intf
->altsetting
[0];
1708 intf
->cur_altsetting
= alt
;
1709 usb_enable_interface(dev
, intf
, true);
1710 intf
->dev
.parent
= &dev
->dev
;
1711 intf
->dev
.driver
= NULL
;
1712 intf
->dev
.bus
= &usb_bus_type
;
1713 intf
->dev
.type
= &usb_if_device_type
;
1714 intf
->dev
.groups
= usb_interface_groups
;
1715 intf
->dev
.dma_mask
= dev
->dev
.dma_mask
;
1716 INIT_WORK(&intf
->reset_ws
, __usb_queue_reset_device
);
1717 device_initialize(&intf
->dev
);
1718 mark_quiesced(intf
);
1719 dev_set_name(&intf
->dev
, "%d-%s:%d.%d",
1720 dev
->bus
->busnum
, dev
->devpath
,
1721 configuration
, alt
->desc
.bInterfaceNumber
);
1723 kfree(new_interfaces
);
1725 if (cp
->string
== NULL
&&
1726 !(dev
->quirks
& USB_QUIRK_CONFIG_INTF_STRINGS
))
1727 cp
->string
= usb_cache_string(dev
, cp
->desc
.iConfiguration
);
1729 /* Now that all the interfaces are set up, register them
1730 * to trigger binding of drivers to interfaces. probe()
1731 * routines may install different altsettings and may
1732 * claim() any interfaces not yet bound. Many class drivers
1733 * need that: CDC, audio, video, etc.
1735 for (i
= 0; i
< nintf
; ++i
) {
1736 struct usb_interface
*intf
= cp
->interface
[i
];
1739 "adding %s (config #%d, interface %d)\n",
1740 dev_name(&intf
->dev
), configuration
,
1741 intf
->cur_altsetting
->desc
.bInterfaceNumber
);
1742 ret
= device_add(&intf
->dev
);
1744 dev_err(&dev
->dev
, "device_add(%s) --> %d\n",
1745 dev_name(&intf
->dev
), ret
);
1748 create_intf_ep_devs(intf
);
1751 usb_autosuspend_device(dev
);
1755 static LIST_HEAD(set_config_list
);
1756 static DEFINE_SPINLOCK(set_config_lock
);
1758 struct set_config_request
{
1759 struct usb_device
*udev
;
1761 struct work_struct work
;
1762 struct list_head node
;
1765 /* Worker routine for usb_driver_set_configuration() */
1766 static void driver_set_config_work(struct work_struct
*work
)
1768 struct set_config_request
*req
=
1769 container_of(work
, struct set_config_request
, work
);
1770 struct usb_device
*udev
= req
->udev
;
1772 usb_lock_device(udev
);
1773 spin_lock(&set_config_lock
);
1774 list_del(&req
->node
);
1775 spin_unlock(&set_config_lock
);
1777 if (req
->config
>= -1) /* Is req still valid? */
1778 usb_set_configuration(udev
, req
->config
);
1779 usb_unlock_device(udev
);
1784 /* Cancel pending Set-Config requests for a device whose configuration
1787 static void cancel_async_set_config(struct usb_device
*udev
)
1789 struct set_config_request
*req
;
1791 spin_lock(&set_config_lock
);
1792 list_for_each_entry(req
, &set_config_list
, node
) {
1793 if (req
->udev
== udev
)
1794 req
->config
= -999; /* Mark as cancelled */
1796 spin_unlock(&set_config_lock
);
1800 * usb_driver_set_configuration - Provide a way for drivers to change device configurations
1801 * @udev: the device whose configuration is being updated
1802 * @config: the configuration being chosen.
1803 * Context: In process context, must be able to sleep
1805 * Device interface drivers are not allowed to change device configurations.
1806 * This is because changing configurations will destroy the interface the
1807 * driver is bound to and create new ones; it would be like a floppy-disk
1808 * driver telling the computer to replace the floppy-disk drive with a
1811 * Still, in certain specialized circumstances the need may arise. This
1812 * routine gets around the normal restrictions by using a work thread to
1813 * submit the change-config request.
1815 * Returns 0 if the request was succesfully queued, error code otherwise.
1816 * The caller has no way to know whether the queued request will eventually
1819 int usb_driver_set_configuration(struct usb_device
*udev
, int config
)
1821 struct set_config_request
*req
;
1823 req
= kmalloc(sizeof(*req
), GFP_KERNEL
);
1827 req
->config
= config
;
1828 INIT_WORK(&req
->work
, driver_set_config_work
);
1830 spin_lock(&set_config_lock
);
1831 list_add(&req
->node
, &set_config_list
);
1832 spin_unlock(&set_config_lock
);
1835 schedule_work(&req
->work
);
1838 EXPORT_SYMBOL_GPL(usb_driver_set_configuration
);