1 #include <linux/module.h>
2 #include <linux/string.h>
3 #include <linux/bitops.h>
4 #include <linux/slab.h>
5 #include <linux/init.h>
6 #include <linux/log2.h>
8 #include <linux/wait.h>
11 #define to_urb(d) container_of(d, struct urb, kref)
13 static DEFINE_SPINLOCK(usb_reject_lock
);
15 static void urb_destroy(struct kref
*kref
)
17 struct urb
*urb
= to_urb(kref
);
19 if (urb
->transfer_flags
& URB_FREE_BUFFER
)
20 kfree(urb
->transfer_buffer
);
26 * usb_init_urb - initializes a urb so that it can be used by a USB driver
27 * @urb: pointer to the urb to initialize
29 * Initializes a urb so that the USB subsystem can use it properly.
31 * If a urb is created with a call to usb_alloc_urb() it is not
32 * necessary to call this function. Only use this if you allocate the
33 * space for a struct urb on your own. If you call this function, be
34 * careful when freeing the memory for your urb that it is no longer in
35 * use by the USB core.
37 * Only use this function if you _really_ understand what you are doing.
39 void usb_init_urb(struct urb
*urb
)
42 memset(urb
, 0, sizeof(*urb
));
43 kref_init(&urb
->kref
);
44 INIT_LIST_HEAD(&urb
->anchor_list
);
47 EXPORT_SYMBOL_GPL(usb_init_urb
);
50 * usb_alloc_urb - creates a new urb for a USB driver to use
51 * @iso_packets: number of iso packets for this urb
52 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
53 * valid options for this.
55 * Creates an urb for the USB driver to use, initializes a few internal
56 * structures, incrementes the usage counter, and returns a pointer to it.
58 * If no memory is available, NULL is returned.
60 * If the driver want to use this urb for interrupt, control, or bulk
61 * endpoints, pass '0' as the number of iso packets.
63 * The driver must call usb_free_urb() when it is finished with the urb.
65 struct urb
*usb_alloc_urb(int iso_packets
, gfp_t mem_flags
)
69 urb
= kmalloc(sizeof(struct urb
) +
70 iso_packets
* sizeof(struct usb_iso_packet_descriptor
),
73 err("alloc_urb: kmalloc failed");
79 EXPORT_SYMBOL_GPL(usb_alloc_urb
);
82 * usb_free_urb - frees the memory used by a urb when all users of it are finished
83 * @urb: pointer to the urb to free, may be NULL
85 * Must be called when a user of a urb is finished with it. When the last user
86 * of the urb calls this function, the memory of the urb is freed.
88 * Note: The transfer buffer associated with the urb is not freed, that must be
91 void usb_free_urb(struct urb
*urb
)
94 kref_put(&urb
->kref
, urb_destroy
);
96 EXPORT_SYMBOL_GPL(usb_free_urb
);
99 * usb_get_urb - increments the reference count of the urb
100 * @urb: pointer to the urb to modify, may be NULL
102 * This must be called whenever a urb is transferred from a device driver to a
103 * host controller driver. This allows proper reference counting to happen
106 * A pointer to the urb with the incremented reference counter is returned.
108 struct urb
*usb_get_urb(struct urb
*urb
)
111 kref_get(&urb
->kref
);
114 EXPORT_SYMBOL_GPL(usb_get_urb
);
117 * usb_anchor_urb - anchors an URB while it is processed
118 * @urb: pointer to the urb to anchor
119 * @anchor: pointer to the anchor
121 * This can be called to have access to URBs which are to be executed
122 * without bothering to track them
124 void usb_anchor_urb(struct urb
*urb
, struct usb_anchor
*anchor
)
128 spin_lock_irqsave(&anchor
->lock
, flags
);
130 list_add_tail(&urb
->anchor_list
, &anchor
->urb_list
);
131 urb
->anchor
= anchor
;
133 if (unlikely(anchor
->poisoned
)) {
134 spin_lock(&usb_reject_lock
);
136 spin_unlock(&usb_reject_lock
);
139 spin_unlock_irqrestore(&anchor
->lock
, flags
);
141 EXPORT_SYMBOL_GPL(usb_anchor_urb
);
144 * usb_unanchor_urb - unanchors an URB
145 * @urb: pointer to the urb to anchor
147 * Call this to stop the system keeping track of this URB
149 void usb_unanchor_urb(struct urb
*urb
)
152 struct usb_anchor
*anchor
;
157 anchor
= urb
->anchor
;
161 spin_lock_irqsave(&anchor
->lock
, flags
);
162 if (unlikely(anchor
!= urb
->anchor
)) {
163 /* we've lost the race to another thread */
164 spin_unlock_irqrestore(&anchor
->lock
, flags
);
168 list_del(&urb
->anchor_list
);
169 spin_unlock_irqrestore(&anchor
->lock
, flags
);
171 if (list_empty(&anchor
->urb_list
))
172 wake_up(&anchor
->wait
);
174 EXPORT_SYMBOL_GPL(usb_unanchor_urb
);
176 /*-------------------------------------------------------------------*/
179 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
180 * @urb: pointer to the urb describing the request
181 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
182 * of valid options for this.
184 * This submits a transfer request, and transfers control of the URB
185 * describing that request to the USB subsystem. Request completion will
186 * be indicated later, asynchronously, by calling the completion handler.
187 * The three types of completion are success, error, and unlink
188 * (a software-induced fault, also called "request cancellation").
190 * URBs may be submitted in interrupt context.
192 * The caller must have correctly initialized the URB before submitting
193 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
194 * available to ensure that most fields are correctly initialized, for
195 * the particular kind of transfer, although they will not initialize
196 * any transfer flags.
198 * Successful submissions return 0; otherwise this routine returns a
199 * negative error number. If the submission is successful, the complete()
200 * callback from the URB will be called exactly once, when the USB core and
201 * Host Controller Driver (HCD) are finished with the URB. When the completion
202 * function is called, control of the URB is returned to the device
203 * driver which issued the request. The completion handler may then
204 * immediately free or reuse that URB.
206 * With few exceptions, USB device drivers should never access URB fields
207 * provided by usbcore or the HCD until its complete() is called.
208 * The exceptions relate to periodic transfer scheduling. For both
209 * interrupt and isochronous urbs, as part of successful URB submission
210 * urb->interval is modified to reflect the actual transfer period used
211 * (normally some power of two units). And for isochronous urbs,
212 * urb->start_frame is modified to reflect when the URB's transfers were
213 * scheduled to start. Not all isochronous transfer scheduling policies
214 * will work, but most host controller drivers should easily handle ISO
215 * queues going from now until 10-200 msec into the future.
217 * For control endpoints, the synchronous usb_control_msg() call is
218 * often used (in non-interrupt context) instead of this call.
219 * That is often used through convenience wrappers, for the requests
220 * that are standardized in the USB 2.0 specification. For bulk
221 * endpoints, a synchronous usb_bulk_msg() call is available.
225 * URBs may be submitted to endpoints before previous ones complete, to
226 * minimize the impact of interrupt latencies and system overhead on data
227 * throughput. With that queuing policy, an endpoint's queue would never
228 * be empty. This is required for continuous isochronous data streams,
229 * and may also be required for some kinds of interrupt transfers. Such
230 * queuing also maximizes bandwidth utilization by letting USB controllers
231 * start work on later requests before driver software has finished the
232 * completion processing for earlier (successful) requests.
234 * As of Linux 2.6, all USB endpoint transfer queues support depths greater
235 * than one. This was previously a HCD-specific behavior, except for ISO
236 * transfers. Non-isochronous endpoint queues are inactive during cleanup
237 * after faults (transfer errors or cancellation).
239 * Reserved Bandwidth Transfers:
241 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
242 * using the interval specified in the urb. Submitting the first urb to
243 * the endpoint reserves the bandwidth necessary to make those transfers.
244 * If the USB subsystem can't allocate sufficient bandwidth to perform
245 * the periodic request, submitting such a periodic request should fail.
247 * Device drivers must explicitly request that repetition, by ensuring that
248 * some URB is always on the endpoint's queue (except possibly for short
249 * periods during completion callacks). When there is no longer an urb
250 * queued, the endpoint's bandwidth reservation is canceled. This means
251 * drivers can use their completion handlers to ensure they keep bandwidth
252 * they need, by reinitializing and resubmitting the just-completed urb
253 * until the driver longer needs that periodic bandwidth.
257 * The general rules for how to decide which mem_flags to use
258 * are the same as for kmalloc. There are four
259 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
262 * GFP_NOFS is not ever used, as it has not been implemented yet.
264 * GFP_ATOMIC is used when
265 * (a) you are inside a completion handler, an interrupt, bottom half,
266 * tasklet or timer, or
267 * (b) you are holding a spinlock or rwlock (does not apply to
269 * (c) current->state != TASK_RUNNING, this is the case only after
272 * GFP_NOIO is used in the block io path and error handling of storage
275 * All other situations use GFP_KERNEL.
277 * Some more specific rules for mem_flags can be inferred, such as
278 * (1) start_xmit, timeout, and receive methods of network drivers must
279 * use GFP_ATOMIC (they are called with a spinlock held);
280 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
281 * called with a spinlock held);
282 * (3) If you use a kernel thread with a network driver you must use
283 * GFP_NOIO, unless (b) or (c) apply;
284 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
285 * apply or your are in a storage driver's block io path;
286 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
287 * (6) changing firmware on a running storage or net device uses
288 * GFP_NOIO, unless b) or c) apply
291 int usb_submit_urb(struct urb
*urb
, gfp_t mem_flags
)
294 struct usb_device
*dev
;
295 struct usb_host_endpoint
*ep
;
298 if (!urb
|| urb
->hcpriv
|| !urb
->complete
)
301 if ((!dev
) || (dev
->state
< USB_STATE_DEFAULT
))
304 /* For now, get the endpoint from the pipe. Eventually drivers
305 * will be required to set urb->ep directly and we will eliminate
308 ep
= (usb_pipein(urb
->pipe
) ? dev
->ep_in
: dev
->ep_out
)
309 [usb_pipeendpoint(urb
->pipe
)];
314 urb
->status
= -EINPROGRESS
;
315 urb
->actual_length
= 0;
317 /* Lots of sanity checks, so HCDs can rely on clean data
318 * and don't need to duplicate tests
320 xfertype
= usb_endpoint_type(&ep
->desc
);
321 if (xfertype
== USB_ENDPOINT_XFER_CONTROL
) {
322 struct usb_ctrlrequest
*setup
=
323 (struct usb_ctrlrequest
*) urb
->setup_packet
;
327 is_out
= !(setup
->bRequestType
& USB_DIR_IN
) ||
330 is_out
= usb_endpoint_dir_out(&ep
->desc
);
333 /* Cache the direction for later use */
334 urb
->transfer_flags
= (urb
->transfer_flags
& ~URB_DIR_MASK
) |
335 (is_out
? URB_DIR_OUT
: URB_DIR_IN
);
337 if (xfertype
!= USB_ENDPOINT_XFER_CONTROL
&&
338 dev
->state
< USB_STATE_CONFIGURED
)
341 max
= le16_to_cpu(ep
->desc
.wMaxPacketSize
);
344 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
345 usb_endpoint_num(&ep
->desc
), is_out
? "out" : "in",
350 /* periodic transfers limit size per frame/uframe,
351 * but drivers only control those sizes for ISO.
352 * while we're checking, initialize return status.
354 if (xfertype
== USB_ENDPOINT_XFER_ISOC
) {
357 /* "high bandwidth" mode, 1-3 packets/uframe? */
358 if (dev
->speed
== USB_SPEED_HIGH
) {
359 int mult
= 1 + ((max
>> 11) & 0x03);
364 if (urb
->number_of_packets
<= 0)
366 for (n
= 0; n
< urb
->number_of_packets
; n
++) {
367 len
= urb
->iso_frame_desc
[n
].length
;
368 if (len
< 0 || len
> max
)
370 urb
->iso_frame_desc
[n
].status
= -EXDEV
;
371 urb
->iso_frame_desc
[n
].actual_length
= 0;
375 /* the I/O buffer must be mapped/unmapped, except when length=0 */
376 if (urb
->transfer_buffer_length
< 0)
380 /* stuff that drivers shouldn't do, but which shouldn't
381 * cause problems in HCDs if they get it wrong.
384 unsigned int orig_flags
= urb
->transfer_flags
;
385 unsigned int allowed
;
387 /* enforce simple/standard policy */
388 allowed
= (URB_NO_TRANSFER_DMA_MAP
| URB_NO_SETUP_DMA_MAP
|
389 URB_NO_INTERRUPT
| URB_DIR_MASK
| URB_FREE_BUFFER
);
391 case USB_ENDPOINT_XFER_BULK
:
393 allowed
|= URB_ZERO_PACKET
;
395 case USB_ENDPOINT_XFER_CONTROL
:
396 allowed
|= URB_NO_FSBR
; /* only affects UHCI */
398 default: /* all non-iso endpoints */
400 allowed
|= URB_SHORT_NOT_OK
;
402 case USB_ENDPOINT_XFER_ISOC
:
403 allowed
|= URB_ISO_ASAP
;
406 urb
->transfer_flags
&= allowed
;
408 /* fail if submitter gave bogus flags */
409 if (urb
->transfer_flags
!= orig_flags
) {
410 err("BOGUS urb flags, %x --> %x",
411 orig_flags
, urb
->transfer_flags
);
417 * Force periodic transfer intervals to be legal values that are
418 * a power of two (so HCDs don't need to).
420 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
421 * supports different values... this uses EHCI/UHCI defaults (and
422 * EHCI can use smaller non-default values).
425 case USB_ENDPOINT_XFER_ISOC
:
426 case USB_ENDPOINT_XFER_INT
:
428 if (urb
->interval
<= 0)
431 switch (dev
->speed
) {
432 case USB_SPEED_HIGH
: /* units are microframes */
433 /* NOTE usb handles 2^15 */
434 if (urb
->interval
> (1024 * 8))
435 urb
->interval
= 1024 * 8;
438 case USB_SPEED_FULL
: /* units are frames/msec */
440 if (xfertype
== USB_ENDPOINT_XFER_INT
) {
441 if (urb
->interval
> 255)
443 /* NOTE ohci only handles up to 32 */
446 if (urb
->interval
> 1024)
447 urb
->interval
= 1024;
448 /* NOTE usb and ohci handle up to 2^15 */
455 /* Round down to a power of 2, no more than max */
456 urb
->interval
= min(max
, 1 << ilog2(urb
->interval
));
459 return usb_hcd_submit_urb(urb
, mem_flags
);
461 EXPORT_SYMBOL_GPL(usb_submit_urb
);
463 /*-------------------------------------------------------------------*/
466 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
467 * @urb: pointer to urb describing a previously submitted request,
470 * This routine cancels an in-progress request. URBs complete only once
471 * per submission, and may be canceled only once per submission.
472 * Successful cancellation means termination of @urb will be expedited
473 * and the completion handler will be called with a status code
474 * indicating that the request has been canceled (rather than any other
477 * This request is always asynchronous. Success is indicated by
478 * returning -EINPROGRESS, at which time the URB will probably not yet
479 * have been given back to the device driver. When it is eventually
480 * called, the completion function will see @urb->status == -ECONNRESET.
481 * Failure is indicated by usb_unlink_urb() returning any other value.
482 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
483 * never submitted, or it was unlinked before, or the hardware is already
484 * finished with it), even if the completion handler has not yet run.
486 * Unlinking and Endpoint Queues:
488 * [The behaviors and guarantees described below do not apply to virtual
489 * root hubs but only to endpoint queues for physical USB devices.]
491 * Host Controller Drivers (HCDs) place all the URBs for a particular
492 * endpoint in a queue. Normally the queue advances as the controller
493 * hardware processes each request. But when an URB terminates with an
494 * error its queue generally stops (see below), at least until that URB's
495 * completion routine returns. It is guaranteed that a stopped queue
496 * will not restart until all its unlinked URBs have been fully retired,
497 * with their completion routines run, even if that's not until some time
498 * after the original completion handler returns. The same behavior and
499 * guarantee apply when an URB terminates because it was unlinked.
501 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
502 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
503 * and -EREMOTEIO. Control endpoint queues behave the same way except
504 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
505 * for isochronous endpoints are treated differently, because they must
506 * advance at fixed rates. Such queues do not stop when an URB
507 * encounters an error or is unlinked. An unlinked isochronous URB may
508 * leave a gap in the stream of packets; it is undefined whether such
509 * gaps can be filled in.
511 * Note that early termination of an URB because a short packet was
512 * received will generate a -EREMOTEIO error if and only if the
513 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
514 * drivers can build deep queues for large or complex bulk transfers
515 * and clean them up reliably after any sort of aborted transfer by
516 * unlinking all pending URBs at the first fault.
518 * When a control URB terminates with an error other than -EREMOTEIO, it
519 * is quite likely that the status stage of the transfer will not take
522 int usb_unlink_urb(struct urb
*urb
)
530 return usb_hcd_unlink_urb(urb
, -ECONNRESET
);
532 EXPORT_SYMBOL_GPL(usb_unlink_urb
);
535 * usb_kill_urb - cancel a transfer request and wait for it to finish
536 * @urb: pointer to URB describing a previously submitted request,
539 * This routine cancels an in-progress request. It is guaranteed that
540 * upon return all completion handlers will have finished and the URB
541 * will be totally idle and available for reuse. These features make
542 * this an ideal way to stop I/O in a disconnect() callback or close()
543 * function. If the request has not already finished or been unlinked
544 * the completion handler will see urb->status == -ENOENT.
546 * While the routine is running, attempts to resubmit the URB will fail
547 * with error -EPERM. Thus even if the URB's completion handler always
548 * tries to resubmit, it will not succeed and the URB will become idle.
550 * This routine may not be used in an interrupt context (such as a bottom
551 * half or a completion handler), or when holding a spinlock, or in other
552 * situations where the caller can't schedule().
554 void usb_kill_urb(struct urb
*urb
)
557 if (!(urb
&& urb
->dev
&& urb
->ep
))
559 spin_lock_irq(&usb_reject_lock
);
561 spin_unlock_irq(&usb_reject_lock
);
563 usb_hcd_unlink_urb(urb
, -ENOENT
);
564 wait_event(usb_kill_urb_queue
, atomic_read(&urb
->use_count
) == 0);
566 spin_lock_irq(&usb_reject_lock
);
568 spin_unlock_irq(&usb_reject_lock
);
570 EXPORT_SYMBOL_GPL(usb_kill_urb
);
573 * usb_poison_urb - reliably kill a transfer and prevent further use of an URB
574 * @urb: pointer to URB describing a previously submitted request,
577 * This routine cancels an in-progress request. It is guaranteed that
578 * upon return all completion handlers will have finished and the URB
579 * will be totally idle and cannot be reused. These features make
580 * this an ideal way to stop I/O in a disconnect() callback.
581 * If the request has not already finished or been unlinked
582 * the completion handler will see urb->status == -ENOENT.
584 * After and while the routine runs, attempts to resubmit the URB will fail
585 * with error -EPERM. Thus even if the URB's completion handler always
586 * tries to resubmit, it will not succeed and the URB will become idle.
588 * This routine may not be used in an interrupt context (such as a bottom
589 * half or a completion handler), or when holding a spinlock, or in other
590 * situations where the caller can't schedule().
592 void usb_poison_urb(struct urb
*urb
)
595 if (!(urb
&& urb
->dev
&& urb
->ep
))
597 spin_lock_irq(&usb_reject_lock
);
599 spin_unlock_irq(&usb_reject_lock
);
601 usb_hcd_unlink_urb(urb
, -ENOENT
);
602 wait_event(usb_kill_urb_queue
, atomic_read(&urb
->use_count
) == 0);
604 EXPORT_SYMBOL_GPL(usb_poison_urb
);
606 void usb_unpoison_urb(struct urb
*urb
)
613 spin_lock_irqsave(&usb_reject_lock
, flags
);
615 spin_unlock_irqrestore(&usb_reject_lock
, flags
);
617 EXPORT_SYMBOL_GPL(usb_unpoison_urb
);
620 * usb_kill_anchored_urbs - cancel transfer requests en masse
621 * @anchor: anchor the requests are bound to
623 * this allows all outstanding URBs to be killed starting
624 * from the back of the queue
626 void usb_kill_anchored_urbs(struct usb_anchor
*anchor
)
630 spin_lock_irq(&anchor
->lock
);
631 while (!list_empty(&anchor
->urb_list
)) {
632 victim
= list_entry(anchor
->urb_list
.prev
, struct urb
,
634 /* we must make sure the URB isn't freed before we kill it*/
636 spin_unlock_irq(&anchor
->lock
);
637 /* this will unanchor the URB */
638 usb_kill_urb(victim
);
640 spin_lock_irq(&anchor
->lock
);
642 spin_unlock_irq(&anchor
->lock
);
644 EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs
);
648 * usb_poison_anchored_urbs - cease all traffic from an anchor
649 * @anchor: anchor the requests are bound to
651 * this allows all outstanding URBs to be poisoned starting
652 * from the back of the queue. Newly added URBs will also be
655 void usb_poison_anchored_urbs(struct usb_anchor
*anchor
)
659 spin_lock_irq(&anchor
->lock
);
660 anchor
->poisoned
= 1;
661 while (!list_empty(&anchor
->urb_list
)) {
662 victim
= list_entry(anchor
->urb_list
.prev
, struct urb
,
664 /* we must make sure the URB isn't freed before we kill it*/
666 spin_unlock_irq(&anchor
->lock
);
667 /* this will unanchor the URB */
668 usb_poison_urb(victim
);
670 spin_lock_irq(&anchor
->lock
);
672 spin_unlock_irq(&anchor
->lock
);
674 EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs
);
676 * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse
677 * @anchor: anchor the requests are bound to
679 * this allows all outstanding URBs to be unlinked starting
680 * from the back of the queue. This function is asynchronous.
681 * The unlinking is just tiggered. It may happen after this
682 * function has returned.
684 void usb_unlink_anchored_urbs(struct usb_anchor
*anchor
)
689 spin_lock_irqsave(&anchor
->lock
, flags
);
690 while (!list_empty(&anchor
->urb_list
)) {
691 victim
= list_entry(anchor
->urb_list
.prev
, struct urb
,
694 spin_unlock_irqrestore(&anchor
->lock
, flags
);
695 /* this will unanchor the URB */
696 usb_unlink_urb(victim
);
698 spin_lock_irqsave(&anchor
->lock
, flags
);
700 spin_unlock_irqrestore(&anchor
->lock
, flags
);
702 EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs
);
705 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
706 * @anchor: the anchor you want to become unused
707 * @timeout: how long you are willing to wait in milliseconds
709 * Call this is you want to be sure all an anchor's
712 int usb_wait_anchor_empty_timeout(struct usb_anchor
*anchor
,
713 unsigned int timeout
)
715 return wait_event_timeout(anchor
->wait
, list_empty(&anchor
->urb_list
),
716 msecs_to_jiffies(timeout
));
718 EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout
);