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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>
7#include <linux/usb.h>
8#include <linux/wait.h>
9#include <linux/usb/hcd.h>
10
11#define to_urb(d) container_of(d, struct urb, kref)
12
13
14static void urb_destroy(struct kref *kref)
15{
16 struct urb *urb = to_urb(kref);
17
18 if (urb->transfer_flags & URB_FREE_BUFFER)
19 kfree(urb->transfer_buffer);
20
21 kfree(urb);
22}
23
24/**
25 * usb_init_urb - initializes a urb so that it can be used by a USB driver
26 * @urb: pointer to the urb to initialize
27 *
28 * Initializes a urb so that the USB subsystem can use it properly.
29 *
30 * If a urb is created with a call to usb_alloc_urb() it is not
31 * necessary to call this function. Only use this if you allocate the
32 * space for a struct urb on your own. If you call this function, be
33 * careful when freeing the memory for your urb that it is no longer in
34 * use by the USB core.
35 *
36 * Only use this function if you _really_ understand what you are doing.
37 */
38void usb_init_urb(struct urb *urb)
39{
40 if (urb) {
41 memset(urb, 0, sizeof(*urb));
42 kref_init(&urb->kref);
43 INIT_LIST_HEAD(&urb->anchor_list);
44 }
45}
46EXPORT_SYMBOL_GPL(usb_init_urb);
47
48/**
49 * usb_alloc_urb - creates a new urb for a USB driver to use
50 * @iso_packets: number of iso packets for this urb
51 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
52 * valid options for this.
53 *
54 * Creates an urb for the USB driver to use, initializes a few internal
55 * structures, incrementes the usage counter, and returns a pointer to it.
56 *
57 * If no memory is available, NULL is returned.
58 *
59 * If the driver want to use this urb for interrupt, control, or bulk
60 * endpoints, pass '0' as the number of iso packets.
61 *
62 * The driver must call usb_free_urb() when it is finished with the urb.
63 */
64struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags)
65{
66 struct urb *urb;
67
68 urb = kmalloc(sizeof(struct urb) +
69 iso_packets * sizeof(struct usb_iso_packet_descriptor),
70 mem_flags);
71 if (!urb) {
72 printk(KERN_ERR "alloc_urb: kmalloc failed\n");
73 return NULL;
74 }
75 usb_init_urb(urb);
76 return urb;
77}
78EXPORT_SYMBOL_GPL(usb_alloc_urb);
79
80/**
81 * usb_free_urb - frees the memory used by a urb when all users of it are finished
82 * @urb: pointer to the urb to free, may be NULL
83 *
84 * Must be called when a user of a urb is finished with it. When the last user
85 * of the urb calls this function, the memory of the urb is freed.
86 *
87 * Note: The transfer buffer associated with the urb is not freed unless the
88 * URB_FREE_BUFFER transfer flag is set.
89 */
90void usb_free_urb(struct urb *urb)
91{
92 if (urb)
93 kref_put(&urb->kref, urb_destroy);
94}
95EXPORT_SYMBOL_GPL(usb_free_urb);
96
97/**
98 * usb_get_urb - increments the reference count of the urb
99 * @urb: pointer to the urb to modify, may be NULL
100 *
101 * This must be called whenever a urb is transferred from a device driver to a
102 * host controller driver. This allows proper reference counting to happen
103 * for urbs.
104 *
105 * A pointer to the urb with the incremented reference counter is returned.
106 */
107struct urb *usb_get_urb(struct urb *urb)
108{
109 if (urb)
110 kref_get(&urb->kref);
111 return urb;
112}
113EXPORT_SYMBOL_GPL(usb_get_urb);
114
115/**
116 * usb_anchor_urb - anchors an URB while it is processed
117 * @urb: pointer to the urb to anchor
118 * @anchor: pointer to the anchor
119 *
120 * This can be called to have access to URBs which are to be executed
121 * without bothering to track them
122 */
123void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor)
124{
125 unsigned long flags;
126
127 spin_lock_irqsave(&anchor->lock, flags);
128 usb_get_urb(urb);
129 list_add_tail(&urb->anchor_list, &anchor->urb_list);
130 urb->anchor = anchor;
131
132 if (unlikely(anchor->poisoned)) {
133 atomic_inc(&urb->reject);
134 }
135
136 spin_unlock_irqrestore(&anchor->lock, flags);
137}
138EXPORT_SYMBOL_GPL(usb_anchor_urb);
139
140/* Callers must hold anchor->lock */
141static void __usb_unanchor_urb(struct urb *urb, struct usb_anchor *anchor)
142{
143 urb->anchor = NULL;
144 list_del(&urb->anchor_list);
145 usb_put_urb(urb);
146 if (list_empty(&anchor->urb_list))
147 wake_up(&anchor->wait);
148}
149
150/**
151 * usb_unanchor_urb - unanchors an URB
152 * @urb: pointer to the urb to anchor
153 *
154 * Call this to stop the system keeping track of this URB
155 */
156void usb_unanchor_urb(struct urb *urb)
157{
158 unsigned long flags;
159 struct usb_anchor *anchor;
160
161 if (!urb)
162 return;
163
164 anchor = urb->anchor;
165 if (!anchor)
166 return;
167
168 spin_lock_irqsave(&anchor->lock, flags);
169 /*
170 * At this point, we could be competing with another thread which
171 * has the same intention. To protect the urb from being unanchored
172 * twice, only the winner of the race gets the job.
173 */
174 if (likely(anchor == urb->anchor))
175 __usb_unanchor_urb(urb, anchor);
176 spin_unlock_irqrestore(&anchor->lock, flags);
177}
178EXPORT_SYMBOL_GPL(usb_unanchor_urb);
179
180/*-------------------------------------------------------------------*/
181
182/**
183 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
184 * @urb: pointer to the urb describing the request
185 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
186 * of valid options for this.
187 *
188 * This submits a transfer request, and transfers control of the URB
189 * describing that request to the USB subsystem. Request completion will
190 * be indicated later, asynchronously, by calling the completion handler.
191 * The three types of completion are success, error, and unlink
192 * (a software-induced fault, also called "request cancellation").
193 *
194 * URBs may be submitted in interrupt context.
195 *
196 * The caller must have correctly initialized the URB before submitting
197 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
198 * available to ensure that most fields are correctly initialized, for
199 * the particular kind of transfer, although they will not initialize
200 * any transfer flags.
201 *
202 * Successful submissions return 0; otherwise this routine returns a
203 * negative error number. If the submission is successful, the complete()
204 * callback from the URB will be called exactly once, when the USB core and
205 * Host Controller Driver (HCD) are finished with the URB. When the completion
206 * function is called, control of the URB is returned to the device
207 * driver which issued the request. The completion handler may then
208 * immediately free or reuse that URB.
209 *
210 * With few exceptions, USB device drivers should never access URB fields
211 * provided by usbcore or the HCD until its complete() is called.
212 * The exceptions relate to periodic transfer scheduling. For both
213 * interrupt and isochronous urbs, as part of successful URB submission
214 * urb->interval is modified to reflect the actual transfer period used
215 * (normally some power of two units). And for isochronous urbs,
216 * urb->start_frame is modified to reflect when the URB's transfers were
217 * scheduled to start. Not all isochronous transfer scheduling policies
218 * will work, but most host controller drivers should easily handle ISO
219 * queues going from now until 10-200 msec into the future.
220 *
221 * For control endpoints, the synchronous usb_control_msg() call is
222 * often used (in non-interrupt context) instead of this call.
223 * That is often used through convenience wrappers, for the requests
224 * that are standardized in the USB 2.0 specification. For bulk
225 * endpoints, a synchronous usb_bulk_msg() call is available.
226 *
227 * Request Queuing:
228 *
229 * URBs may be submitted to endpoints before previous ones complete, to
230 * minimize the impact of interrupt latencies and system overhead on data
231 * throughput. With that queuing policy, an endpoint's queue would never
232 * be empty. This is required for continuous isochronous data streams,
233 * and may also be required for some kinds of interrupt transfers. Such
234 * queuing also maximizes bandwidth utilization by letting USB controllers
235 * start work on later requests before driver software has finished the
236 * completion processing for earlier (successful) requests.
237 *
238 * As of Linux 2.6, all USB endpoint transfer queues support depths greater
239 * than one. This was previously a HCD-specific behavior, except for ISO
240 * transfers. Non-isochronous endpoint queues are inactive during cleanup
241 * after faults (transfer errors or cancellation).
242 *
243 * Reserved Bandwidth Transfers:
244 *
245 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
246 * using the interval specified in the urb. Submitting the first urb to
247 * the endpoint reserves the bandwidth necessary to make those transfers.
248 * If the USB subsystem can't allocate sufficient bandwidth to perform
249 * the periodic request, submitting such a periodic request should fail.
250 *
251 * For devices under xHCI, the bandwidth is reserved at configuration time, or
252 * when the alt setting is selected. If there is not enough bus bandwidth, the
253 * configuration/alt setting request will fail. Therefore, submissions to
254 * periodic endpoints on devices under xHCI should never fail due to bandwidth
255 * constraints.
256 *
257 * Device drivers must explicitly request that repetition, by ensuring that
258 * some URB is always on the endpoint's queue (except possibly for short
259 * periods during completion callacks). When there is no longer an urb
260 * queued, the endpoint's bandwidth reservation is canceled. This means
261 * drivers can use their completion handlers to ensure they keep bandwidth
262 * they need, by reinitializing and resubmitting the just-completed urb
263 * until the driver longer needs that periodic bandwidth.
264 *
265 * Memory Flags:
266 *
267 * The general rules for how to decide which mem_flags to use
268 * are the same as for kmalloc. There are four
269 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
270 * GFP_ATOMIC.
271 *
272 * GFP_NOFS is not ever used, as it has not been implemented yet.
273 *
274 * GFP_ATOMIC is used when
275 * (a) you are inside a completion handler, an interrupt, bottom half,
276 * tasklet or timer, or
277 * (b) you are holding a spinlock or rwlock (does not apply to
278 * semaphores), or
279 * (c) current->state != TASK_RUNNING, this is the case only after
280 * you've changed it.
281 *
282 * GFP_NOIO is used in the block io path and error handling of storage
283 * devices.
284 *
285 * All other situations use GFP_KERNEL.
286 *
287 * Some more specific rules for mem_flags can be inferred, such as
288 * (1) start_xmit, timeout, and receive methods of network drivers must
289 * use GFP_ATOMIC (they are called with a spinlock held);
290 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
291 * called with a spinlock held);
292 * (3) If you use a kernel thread with a network driver you must use
293 * GFP_NOIO, unless (b) or (c) apply;
294 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
295 * apply or your are in a storage driver's block io path;
296 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
297 * (6) changing firmware on a running storage or net device uses
298 * GFP_NOIO, unless b) or c) apply
299 *
300 */
301int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
302{
303 int xfertype, max;
304 struct usb_device *dev;
305 struct usb_host_endpoint *ep;
306 int is_out;
307
308 if (!urb || urb->hcpriv || !urb->complete)
309 return -EINVAL;
310 dev = urb->dev;
311 if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED))
312 return -ENODEV;
313
314 /* For now, get the endpoint from the pipe. Eventually drivers
315 * will be required to set urb->ep directly and we will eliminate
316 * urb->pipe.
317 */
318 ep = usb_pipe_endpoint(dev, urb->pipe);
319 if (!ep)
320 return -ENOENT;
321
322 urb->ep = ep;
323 urb->status = -EINPROGRESS;
324 urb->actual_length = 0;
325
326 /* Lots of sanity checks, so HCDs can rely on clean data
327 * and don't need to duplicate tests
328 */
329 xfertype = usb_endpoint_type(&ep->desc);
330 if (xfertype == USB_ENDPOINT_XFER_CONTROL) {
331 struct usb_ctrlrequest *setup =
332 (struct usb_ctrlrequest *) urb->setup_packet;
333
334 if (!setup)
335 return -ENOEXEC;
336 is_out = !(setup->bRequestType & USB_DIR_IN) ||
337 !setup->wLength;
338 } else {
339 is_out = usb_endpoint_dir_out(&ep->desc);
340 }
341
342 /* Clear the internal flags and cache the direction for later use */
343 urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE |
344 URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL |
345 URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL |
346 URB_DMA_SG_COMBINED);
347 urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN);
348
349 if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
350 dev->state < USB_STATE_CONFIGURED)
351 return -ENODEV;
352
353 max = le16_to_cpu(ep->desc.wMaxPacketSize);
354 if (max <= 0) {
355 dev_dbg(&dev->dev,
356 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
357 usb_endpoint_num(&ep->desc), is_out ? "out" : "in",
358 __func__, max);
359 return -EMSGSIZE;
360 }
361
362 /* periodic transfers limit size per frame/uframe,
363 * but drivers only control those sizes for ISO.
364 * while we're checking, initialize return status.
365 */
366 if (xfertype == USB_ENDPOINT_XFER_ISOC) {
367 int n, len;
368
369 /* SuperSpeed isoc endpoints have up to 16 bursts of up to
370 * 3 packets each
371 */
372 if (dev->speed == USB_SPEED_SUPER) {
373 int burst = 1 + ep->ss_ep_comp.bMaxBurst;
374 int mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes);
375 max *= burst;
376 max *= mult;
377 }
378
379 /* "high bandwidth" mode, 1-3 packets/uframe? */
380 if (dev->speed == USB_SPEED_HIGH) {
381 int mult = 1 + ((max >> 11) & 0x03);
382 max &= 0x07ff;
383 max *= mult;
384 }
385
386 if (urb->number_of_packets <= 0)
387 return -EINVAL;
388 for (n = 0; n < urb->number_of_packets; n++) {
389 len = urb->iso_frame_desc[n].length;
390 if (len < 0 || len > max)
391 return -EMSGSIZE;
392 urb->iso_frame_desc[n].status = -EXDEV;
393 urb->iso_frame_desc[n].actual_length = 0;
394 }
395 }
396
397 /* the I/O buffer must be mapped/unmapped, except when length=0 */
398 if (urb->transfer_buffer_length > INT_MAX)
399 return -EMSGSIZE;
400
401#ifdef DEBUG
402 /* stuff that drivers shouldn't do, but which shouldn't
403 * cause problems in HCDs if they get it wrong.
404 */
405 {
406 unsigned int orig_flags = urb->transfer_flags;
407 unsigned int allowed;
408 static int pipetypes[4] = {
409 PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT
410 };
411
412 /* Check that the pipe's type matches the endpoint's type */
413 if (usb_pipetype(urb->pipe) != pipetypes[xfertype]) {
414 dev_err(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n",
415 usb_pipetype(urb->pipe), pipetypes[xfertype]);
416 return -EPIPE; /* The most suitable error code :-) */
417 }
418
419 /* enforce simple/standard policy */
420 allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK |
421 URB_FREE_BUFFER);
422 switch (xfertype) {
423 case USB_ENDPOINT_XFER_BULK:
424 if (is_out)
425 allowed |= URB_ZERO_PACKET;
426 /* FALLTHROUGH */
427 case USB_ENDPOINT_XFER_CONTROL:
428 allowed |= URB_NO_FSBR; /* only affects UHCI */
429 /* FALLTHROUGH */
430 default: /* all non-iso endpoints */
431 if (!is_out)
432 allowed |= URB_SHORT_NOT_OK;
433 break;
434 case USB_ENDPOINT_XFER_ISOC:
435 allowed |= URB_ISO_ASAP;
436 break;
437 }
438 urb->transfer_flags &= allowed;
439
440 /* fail if submitter gave bogus flags */
441 if (urb->transfer_flags != orig_flags) {
442 dev_err(&dev->dev, "BOGUS urb flags, %x --> %x\n",
443 orig_flags, urb->transfer_flags);
444 return -EINVAL;
445 }
446 }
447#endif
448 /*
449 * Force periodic transfer intervals to be legal values that are
450 * a power of two (so HCDs don't need to).
451 *
452 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
453 * supports different values... this uses EHCI/UHCI defaults (and
454 * EHCI can use smaller non-default values).
455 */
456 switch (xfertype) {
457 case USB_ENDPOINT_XFER_ISOC:
458 case USB_ENDPOINT_XFER_INT:
459 /* too small? */
460 switch (dev->speed) {
461 case USB_SPEED_WIRELESS:
462 if (urb->interval < 6)
463 return -EINVAL;
464 break;
465 default:
466 if (urb->interval <= 0)
467 return -EINVAL;
468 break;
469 }
470 /* too big? */
471 switch (dev->speed) {
472 case USB_SPEED_SUPER: /* units are 125us */
473 /* Handle up to 2^(16-1) microframes */
474 if (urb->interval > (1 << 15))
475 return -EINVAL;
476 max = 1 << 15;
477 break;
478 case USB_SPEED_WIRELESS:
479 if (urb->interval > 16)
480 return -EINVAL;
481 break;
482 case USB_SPEED_HIGH: /* units are microframes */
483 /* NOTE usb handles 2^15 */
484 if (urb->interval > (1024 * 8))
485 urb->interval = 1024 * 8;
486 max = 1024 * 8;
487 break;
488 case USB_SPEED_FULL: /* units are frames/msec */
489 case USB_SPEED_LOW:
490 if (xfertype == USB_ENDPOINT_XFER_INT) {
491 if (urb->interval > 255)
492 return -EINVAL;
493 /* NOTE ohci only handles up to 32 */
494 max = 128;
495 } else {
496 if (urb->interval > 1024)
497 urb->interval = 1024;
498 /* NOTE usb and ohci handle up to 2^15 */
499 max = 1024;
500 }
501 break;
502 default:
503 return -EINVAL;
504 }
505 if (dev->speed != USB_SPEED_WIRELESS) {
506 /* Round down to a power of 2, no more than max */
507 urb->interval = min(max, 1 << ilog2(urb->interval));
508 }
509 }
510
511 return usb_hcd_submit_urb(urb, mem_flags);
512}
513EXPORT_SYMBOL_GPL(usb_submit_urb);
514
515/*-------------------------------------------------------------------*/
516
517/**
518 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
519 * @urb: pointer to urb describing a previously submitted request,
520 * may be NULL
521 *
522 * This routine cancels an in-progress request. URBs complete only once
523 * per submission, and may be canceled only once per submission.
524 * Successful cancellation means termination of @urb will be expedited
525 * and the completion handler will be called with a status code
526 * indicating that the request has been canceled (rather than any other
527 * code).
528 *
529 * Drivers should not call this routine or related routines, such as
530 * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect
531 * method has returned. The disconnect function should synchronize with
532 * a driver's I/O routines to insure that all URB-related activity has
533 * completed before it returns.
534 *
535 * This request is always asynchronous. Success is indicated by
536 * returning -EINPROGRESS, at which time the URB will probably not yet
537 * have been given back to the device driver. When it is eventually
538 * called, the completion function will see @urb->status == -ECONNRESET.
539 * Failure is indicated by usb_unlink_urb() returning any other value.
540 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
541 * never submitted, or it was unlinked before, or the hardware is already
542 * finished with it), even if the completion handler has not yet run.
543 *
544 * Unlinking and Endpoint Queues:
545 *
546 * [The behaviors and guarantees described below do not apply to virtual
547 * root hubs but only to endpoint queues for physical USB devices.]
548 *
549 * Host Controller Drivers (HCDs) place all the URBs for a particular
550 * endpoint in a queue. Normally the queue advances as the controller
551 * hardware processes each request. But when an URB terminates with an
552 * error its queue generally stops (see below), at least until that URB's
553 * completion routine returns. It is guaranteed that a stopped queue
554 * will not restart until all its unlinked URBs have been fully retired,
555 * with their completion routines run, even if that's not until some time
556 * after the original completion handler returns. The same behavior and
557 * guarantee apply when an URB terminates because it was unlinked.
558 *
559 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
560 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
561 * and -EREMOTEIO. Control endpoint queues behave the same way except
562 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
563 * for isochronous endpoints are treated differently, because they must
564 * advance at fixed rates. Such queues do not stop when an URB
565 * encounters an error or is unlinked. An unlinked isochronous URB may
566 * leave a gap in the stream of packets; it is undefined whether such
567 * gaps can be filled in.
568 *
569 * Note that early termination of an URB because a short packet was
570 * received will generate a -EREMOTEIO error if and only if the
571 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
572 * drivers can build deep queues for large or complex bulk transfers
573 * and clean them up reliably after any sort of aborted transfer by
574 * unlinking all pending URBs at the first fault.
575 *
576 * When a control URB terminates with an error other than -EREMOTEIO, it
577 * is quite likely that the status stage of the transfer will not take
578 * place.
579 */
580int usb_unlink_urb(struct urb *urb)
581{
582 if (!urb)
583 return -EINVAL;
584 if (!urb->dev)
585 return -ENODEV;
586 if (!urb->ep)
587 return -EIDRM;
588 return usb_hcd_unlink_urb(urb, -ECONNRESET);
589}
590EXPORT_SYMBOL_GPL(usb_unlink_urb);
591
592/**
593 * usb_kill_urb - cancel a transfer request and wait for it to finish
594 * @urb: pointer to URB describing a previously submitted request,
595 * may be NULL
596 *
597 * This routine cancels an in-progress request. It is guaranteed that
598 * upon return all completion handlers will have finished and the URB
599 * will be totally idle and available for reuse. These features make
600 * this an ideal way to stop I/O in a disconnect() callback or close()
601 * function. If the request has not already finished or been unlinked
602 * the completion handler will see urb->status == -ENOENT.
603 *
604 * While the routine is running, attempts to resubmit the URB will fail
605 * with error -EPERM. Thus even if the URB's completion handler always
606 * tries to resubmit, it will not succeed and the URB will become idle.
607 *
608 * This routine may not be used in an interrupt context (such as a bottom
609 * half or a completion handler), or when holding a spinlock, or in other
610 * situations where the caller can't schedule().
611 *
612 * This routine should not be called by a driver after its disconnect
613 * method has returned.
614 */
615void usb_kill_urb(struct urb *urb)
616{
617 might_sleep();
618 if (!(urb && urb->dev && urb->ep))
619 return;
620 atomic_inc(&urb->reject);
621
622 usb_hcd_unlink_urb(urb, -ENOENT);
623 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
624
625 atomic_dec(&urb->reject);
626}
627EXPORT_SYMBOL_GPL(usb_kill_urb);
628
629/**
630 * usb_poison_urb - reliably kill a transfer and prevent further use of an URB
631 * @urb: pointer to URB describing a previously submitted request,
632 * may be NULL
633 *
634 * This routine cancels an in-progress request. It is guaranteed that
635 * upon return all completion handlers will have finished and the URB
636 * will be totally idle and cannot be reused. These features make
637 * this an ideal way to stop I/O in a disconnect() callback.
638 * If the request has not already finished or been unlinked
639 * the completion handler will see urb->status == -ENOENT.
640 *
641 * After and while the routine runs, attempts to resubmit the URB will fail
642 * with error -EPERM. Thus even if the URB's completion handler always
643 * tries to resubmit, it will not succeed and the URB will become idle.
644 *
645 * This routine may not be used in an interrupt context (such as a bottom
646 * half or a completion handler), or when holding a spinlock, or in other
647 * situations where the caller can't schedule().
648 *
649 * This routine should not be called by a driver after its disconnect
650 * method has returned.
651 */
652void usb_poison_urb(struct urb *urb)
653{
654 might_sleep();
655 if (!(urb && urb->dev && urb->ep))
656 return;
657 atomic_inc(&urb->reject);
658
659 usb_hcd_unlink_urb(urb, -ENOENT);
660 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
661}
662EXPORT_SYMBOL_GPL(usb_poison_urb);
663
664void usb_unpoison_urb(struct urb *urb)
665{
666 if (!urb)
667 return;
668
669 atomic_dec(&urb->reject);
670}
671EXPORT_SYMBOL_GPL(usb_unpoison_urb);
672
673/**
674 * usb_kill_anchored_urbs - cancel transfer requests en masse
675 * @anchor: anchor the requests are bound to
676 *
677 * this allows all outstanding URBs to be killed starting
678 * from the back of the queue
679 *
680 * This routine should not be called by a driver after its disconnect
681 * method has returned.
682 */
683void usb_kill_anchored_urbs(struct usb_anchor *anchor)
684{
685 struct urb *victim;
686
687 spin_lock_irq(&anchor->lock);
688 while (!list_empty(&anchor->urb_list)) {
689 victim = list_entry(anchor->urb_list.prev, struct urb,
690 anchor_list);
691 /* we must make sure the URB isn't freed before we kill it*/
692 usb_get_urb(victim);
693 spin_unlock_irq(&anchor->lock);
694 /* this will unanchor the URB */
695 usb_kill_urb(victim);
696 usb_put_urb(victim);
697 spin_lock_irq(&anchor->lock);
698 }
699 spin_unlock_irq(&anchor->lock);
700}
701EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs);
702
703
704/**
705 * usb_poison_anchored_urbs - cease all traffic from an anchor
706 * @anchor: anchor the requests are bound to
707 *
708 * this allows all outstanding URBs to be poisoned starting
709 * from the back of the queue. Newly added URBs will also be
710 * poisoned
711 *
712 * This routine should not be called by a driver after its disconnect
713 * method has returned.
714 */
715void usb_poison_anchored_urbs(struct usb_anchor *anchor)
716{
717 struct urb *victim;
718
719 spin_lock_irq(&anchor->lock);
720 anchor->poisoned = 1;
721 while (!list_empty(&anchor->urb_list)) {
722 victim = list_entry(anchor->urb_list.prev, struct urb,
723 anchor_list);
724 /* we must make sure the URB isn't freed before we kill it*/
725 usb_get_urb(victim);
726 spin_unlock_irq(&anchor->lock);
727 /* this will unanchor the URB */
728 usb_poison_urb(victim);
729 usb_put_urb(victim);
730 spin_lock_irq(&anchor->lock);
731 }
732 spin_unlock_irq(&anchor->lock);
733}
734EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs);
735
736/**
737 * usb_unpoison_anchored_urbs - let an anchor be used successfully again
738 * @anchor: anchor the requests are bound to
739 *
740 * Reverses the effect of usb_poison_anchored_urbs
741 * the anchor can be used normally after it returns
742 */
743void usb_unpoison_anchored_urbs(struct usb_anchor *anchor)
744{
745 unsigned long flags;
746 struct urb *lazarus;
747
748 spin_lock_irqsave(&anchor->lock, flags);
749 list_for_each_entry(lazarus, &anchor->urb_list, anchor_list) {
750 usb_unpoison_urb(lazarus);
751 }
752 anchor->poisoned = 0;
753 spin_unlock_irqrestore(&anchor->lock, flags);
754}
755EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs);
756/**
757 * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse
758 * @anchor: anchor the requests are bound to
759 *
760 * this allows all outstanding URBs to be unlinked starting
761 * from the back of the queue. This function is asynchronous.
762 * The unlinking is just tiggered. It may happen after this
763 * function has returned.
764 *
765 * This routine should not be called by a driver after its disconnect
766 * method has returned.
767 */
768void usb_unlink_anchored_urbs(struct usb_anchor *anchor)
769{
770 struct urb *victim;
771
772 while ((victim = usb_get_from_anchor(anchor)) != NULL) {
773 usb_unlink_urb(victim);
774 usb_put_urb(victim);
775 }
776}
777EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs);
778
779/**
780 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
781 * @anchor: the anchor you want to become unused
782 * @timeout: how long you are willing to wait in milliseconds
783 *
784 * Call this is you want to be sure all an anchor's
785 * URBs have finished
786 */
787int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
788 unsigned int timeout)
789{
790 return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list),
791 msecs_to_jiffies(timeout));
792}
793EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout);
794
795/**
796 * usb_get_from_anchor - get an anchor's oldest urb
797 * @anchor: the anchor whose urb you want
798 *
799 * this will take the oldest urb from an anchor,
800 * unanchor and return it
801 */
802struct urb *usb_get_from_anchor(struct usb_anchor *anchor)
803{
804 struct urb *victim;
805 unsigned long flags;
806
807 spin_lock_irqsave(&anchor->lock, flags);
808 if (!list_empty(&anchor->urb_list)) {
809 victim = list_entry(anchor->urb_list.next, struct urb,
810 anchor_list);
811 usb_get_urb(victim);
812 __usb_unanchor_urb(victim, anchor);
813 } else {
814 victim = NULL;
815 }
816 spin_unlock_irqrestore(&anchor->lock, flags);
817
818 return victim;
819}
820
821EXPORT_SYMBOL_GPL(usb_get_from_anchor);
822
823/**
824 * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs
825 * @anchor: the anchor whose urbs you want to unanchor
826 *
827 * use this to get rid of all an anchor's urbs
828 */
829void usb_scuttle_anchored_urbs(struct usb_anchor *anchor)
830{
831 struct urb *victim;
832 unsigned long flags;
833
834 spin_lock_irqsave(&anchor->lock, flags);
835 while (!list_empty(&anchor->urb_list)) {
836 victim = list_entry(anchor->urb_list.prev, struct urb,
837 anchor_list);
838 __usb_unanchor_urb(victim, anchor);
839 }
840 spin_unlock_irqrestore(&anchor->lock, flags);
841}
842
843EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs);
844
845/**
846 * usb_anchor_empty - is an anchor empty
847 * @anchor: the anchor you want to query
848 *
849 * returns 1 if the anchor has no urbs associated with it
850 */
851int usb_anchor_empty(struct usb_anchor *anchor)
852{
853 return list_empty(&anchor->urb_list);
854}
855
856EXPORT_SYMBOL_GPL(usb_anchor_empty);
857
1#include <linux/module.h>
2#include <linux/string.h>
3#include <linux/bitops.h>
4#include <linux/slab.h>
5#include <linux/log2.h>
6#include <linux/usb.h>
7#include <linux/wait.h>
8#include <linux/usb/hcd.h>
9#include <linux/scatterlist.h>
10
11#define to_urb(d) container_of(d, struct urb, kref)
12
13
14static void urb_destroy(struct kref *kref)
15{
16 struct urb *urb = to_urb(kref);
17
18 if (urb->transfer_flags & URB_FREE_BUFFER)
19 kfree(urb->transfer_buffer);
20
21 kfree(urb);
22}
23
24/**
25 * usb_init_urb - initializes a urb so that it can be used by a USB driver
26 * @urb: pointer to the urb to initialize
27 *
28 * Initializes a urb so that the USB subsystem can use it properly.
29 *
30 * If a urb is created with a call to usb_alloc_urb() it is not
31 * necessary to call this function. Only use this if you allocate the
32 * space for a struct urb on your own. If you call this function, be
33 * careful when freeing the memory for your urb that it is no longer in
34 * use by the USB core.
35 *
36 * Only use this function if you _really_ understand what you are doing.
37 */
38void usb_init_urb(struct urb *urb)
39{
40 if (urb) {
41 memset(urb, 0, sizeof(*urb));
42 kref_init(&urb->kref);
43 INIT_LIST_HEAD(&urb->anchor_list);
44 }
45}
46EXPORT_SYMBOL_GPL(usb_init_urb);
47
48/**
49 * usb_alloc_urb - creates a new urb for a USB driver to use
50 * @iso_packets: number of iso packets for this urb
51 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
52 * valid options for this.
53 *
54 * Creates an urb for the USB driver to use, initializes a few internal
55 * structures, increments the usage counter, and returns a pointer to it.
56 *
57 * If the driver want to use this urb for interrupt, control, or bulk
58 * endpoints, pass '0' as the number of iso packets.
59 *
60 * The driver must call usb_free_urb() when it is finished with the urb.
61 *
62 * Return: A pointer to the new urb, or %NULL if no memory is available.
63 */
64struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags)
65{
66 struct urb *urb;
67
68 urb = kmalloc(sizeof(struct urb) +
69 iso_packets * sizeof(struct usb_iso_packet_descriptor),
70 mem_flags);
71 if (!urb) {
72 printk(KERN_ERR "alloc_urb: kmalloc failed\n");
73 return NULL;
74 }
75 usb_init_urb(urb);
76 return urb;
77}
78EXPORT_SYMBOL_GPL(usb_alloc_urb);
79
80/**
81 * usb_free_urb - frees the memory used by a urb when all users of it are finished
82 * @urb: pointer to the urb to free, may be NULL
83 *
84 * Must be called when a user of a urb is finished with it. When the last user
85 * of the urb calls this function, the memory of the urb is freed.
86 *
87 * Note: The transfer buffer associated with the urb is not freed unless the
88 * URB_FREE_BUFFER transfer flag is set.
89 */
90void usb_free_urb(struct urb *urb)
91{
92 if (urb)
93 kref_put(&urb->kref, urb_destroy);
94}
95EXPORT_SYMBOL_GPL(usb_free_urb);
96
97/**
98 * usb_get_urb - increments the reference count of the urb
99 * @urb: pointer to the urb to modify, may be NULL
100 *
101 * This must be called whenever a urb is transferred from a device driver to a
102 * host controller driver. This allows proper reference counting to happen
103 * for urbs.
104 *
105 * Return: A pointer to the urb with the incremented reference counter.
106 */
107struct urb *usb_get_urb(struct urb *urb)
108{
109 if (urb)
110 kref_get(&urb->kref);
111 return urb;
112}
113EXPORT_SYMBOL_GPL(usb_get_urb);
114
115/**
116 * usb_anchor_urb - anchors an URB while it is processed
117 * @urb: pointer to the urb to anchor
118 * @anchor: pointer to the anchor
119 *
120 * This can be called to have access to URBs which are to be executed
121 * without bothering to track them
122 */
123void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor)
124{
125 unsigned long flags;
126
127 spin_lock_irqsave(&anchor->lock, flags);
128 usb_get_urb(urb);
129 list_add_tail(&urb->anchor_list, &anchor->urb_list);
130 urb->anchor = anchor;
131
132 if (unlikely(anchor->poisoned)) {
133 atomic_inc(&urb->reject);
134 }
135
136 spin_unlock_irqrestore(&anchor->lock, flags);
137}
138EXPORT_SYMBOL_GPL(usb_anchor_urb);
139
140static int usb_anchor_check_wakeup(struct usb_anchor *anchor)
141{
142 return atomic_read(&anchor->suspend_wakeups) == 0 &&
143 list_empty(&anchor->urb_list);
144}
145
146/* Callers must hold anchor->lock */
147static void __usb_unanchor_urb(struct urb *urb, struct usb_anchor *anchor)
148{
149 urb->anchor = NULL;
150 list_del(&urb->anchor_list);
151 usb_put_urb(urb);
152 if (usb_anchor_check_wakeup(anchor))
153 wake_up(&anchor->wait);
154}
155
156/**
157 * usb_unanchor_urb - unanchors an URB
158 * @urb: pointer to the urb to anchor
159 *
160 * Call this to stop the system keeping track of this URB
161 */
162void usb_unanchor_urb(struct urb *urb)
163{
164 unsigned long flags;
165 struct usb_anchor *anchor;
166
167 if (!urb)
168 return;
169
170 anchor = urb->anchor;
171 if (!anchor)
172 return;
173
174 spin_lock_irqsave(&anchor->lock, flags);
175 /*
176 * At this point, we could be competing with another thread which
177 * has the same intention. To protect the urb from being unanchored
178 * twice, only the winner of the race gets the job.
179 */
180 if (likely(anchor == urb->anchor))
181 __usb_unanchor_urb(urb, anchor);
182 spin_unlock_irqrestore(&anchor->lock, flags);
183}
184EXPORT_SYMBOL_GPL(usb_unanchor_urb);
185
186/*-------------------------------------------------------------------*/
187
188/**
189 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
190 * @urb: pointer to the urb describing the request
191 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
192 * of valid options for this.
193 *
194 * This submits a transfer request, and transfers control of the URB
195 * describing that request to the USB subsystem. Request completion will
196 * be indicated later, asynchronously, by calling the completion handler.
197 * The three types of completion are success, error, and unlink
198 * (a software-induced fault, also called "request cancellation").
199 *
200 * URBs may be submitted in interrupt context.
201 *
202 * The caller must have correctly initialized the URB before submitting
203 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
204 * available to ensure that most fields are correctly initialized, for
205 * the particular kind of transfer, although they will not initialize
206 * any transfer flags.
207 *
208 * If the submission is successful, the complete() callback from the URB
209 * will be called exactly once, when the USB core and Host Controller Driver
210 * (HCD) are finished with the URB. When the completion function is called,
211 * control of the URB is returned to the device driver which issued the
212 * request. The completion handler may then immediately free or reuse that
213 * URB.
214 *
215 * With few exceptions, USB device drivers should never access URB fields
216 * provided by usbcore or the HCD until its complete() is called.
217 * The exceptions relate to periodic transfer scheduling. For both
218 * interrupt and isochronous urbs, as part of successful URB submission
219 * urb->interval is modified to reflect the actual transfer period used
220 * (normally some power of two units). And for isochronous urbs,
221 * urb->start_frame is modified to reflect when the URB's transfers were
222 * scheduled to start.
223 *
224 * Not all isochronous transfer scheduling policies will work, but most
225 * host controller drivers should easily handle ISO queues going from now
226 * until 10-200 msec into the future. Drivers should try to keep at
227 * least one or two msec of data in the queue; many controllers require
228 * that new transfers start at least 1 msec in the future when they are
229 * added. If the driver is unable to keep up and the queue empties out,
230 * the behavior for new submissions is governed by the URB_ISO_ASAP flag.
231 * If the flag is set, or if the queue is idle, then the URB is always
232 * assigned to the first available (and not yet expired) slot in the
233 * endpoint's schedule. If the flag is not set and the queue is active
234 * then the URB is always assigned to the next slot in the schedule
235 * following the end of the endpoint's previous URB, even if that slot is
236 * in the past. When a packet is assigned in this way to a slot that has
237 * already expired, the packet is not transmitted and the corresponding
238 * usb_iso_packet_descriptor's status field will return -EXDEV. If this
239 * would happen to all the packets in the URB, submission fails with a
240 * -EXDEV error code.
241 *
242 * For control endpoints, the synchronous usb_control_msg() call is
243 * often used (in non-interrupt context) instead of this call.
244 * That is often used through convenience wrappers, for the requests
245 * that are standardized in the USB 2.0 specification. For bulk
246 * endpoints, a synchronous usb_bulk_msg() call is available.
247 *
248 * Return:
249 * 0 on successful submissions. A negative error number otherwise.
250 *
251 * Request Queuing:
252 *
253 * URBs may be submitted to endpoints before previous ones complete, to
254 * minimize the impact of interrupt latencies and system overhead on data
255 * throughput. With that queuing policy, an endpoint's queue would never
256 * be empty. This is required for continuous isochronous data streams,
257 * and may also be required for some kinds of interrupt transfers. Such
258 * queuing also maximizes bandwidth utilization by letting USB controllers
259 * start work on later requests before driver software has finished the
260 * completion processing for earlier (successful) requests.
261 *
262 * As of Linux 2.6, all USB endpoint transfer queues support depths greater
263 * than one. This was previously a HCD-specific behavior, except for ISO
264 * transfers. Non-isochronous endpoint queues are inactive during cleanup
265 * after faults (transfer errors or cancellation).
266 *
267 * Reserved Bandwidth Transfers:
268 *
269 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
270 * using the interval specified in the urb. Submitting the first urb to
271 * the endpoint reserves the bandwidth necessary to make those transfers.
272 * If the USB subsystem can't allocate sufficient bandwidth to perform
273 * the periodic request, submitting such a periodic request should fail.
274 *
275 * For devices under xHCI, the bandwidth is reserved at configuration time, or
276 * when the alt setting is selected. If there is not enough bus bandwidth, the
277 * configuration/alt setting request will fail. Therefore, submissions to
278 * periodic endpoints on devices under xHCI should never fail due to bandwidth
279 * constraints.
280 *
281 * Device drivers must explicitly request that repetition, by ensuring that
282 * some URB is always on the endpoint's queue (except possibly for short
283 * periods during completion callbacks). When there is no longer an urb
284 * queued, the endpoint's bandwidth reservation is canceled. This means
285 * drivers can use their completion handlers to ensure they keep bandwidth
286 * they need, by reinitializing and resubmitting the just-completed urb
287 * until the driver longer needs that periodic bandwidth.
288 *
289 * Memory Flags:
290 *
291 * The general rules for how to decide which mem_flags to use
292 * are the same as for kmalloc. There are four
293 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
294 * GFP_ATOMIC.
295 *
296 * GFP_NOFS is not ever used, as it has not been implemented yet.
297 *
298 * GFP_ATOMIC is used when
299 * (a) you are inside a completion handler, an interrupt, bottom half,
300 * tasklet or timer, or
301 * (b) you are holding a spinlock or rwlock (does not apply to
302 * semaphores), or
303 * (c) current->state != TASK_RUNNING, this is the case only after
304 * you've changed it.
305 *
306 * GFP_NOIO is used in the block io path and error handling of storage
307 * devices.
308 *
309 * All other situations use GFP_KERNEL.
310 *
311 * Some more specific rules for mem_flags can be inferred, such as
312 * (1) start_xmit, timeout, and receive methods of network drivers must
313 * use GFP_ATOMIC (they are called with a spinlock held);
314 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
315 * called with a spinlock held);
316 * (3) If you use a kernel thread with a network driver you must use
317 * GFP_NOIO, unless (b) or (c) apply;
318 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
319 * apply or your are in a storage driver's block io path;
320 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
321 * (6) changing firmware on a running storage or net device uses
322 * GFP_NOIO, unless b) or c) apply
323 *
324 */
325int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
326{
327 static int pipetypes[4] = {
328 PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT
329 };
330 int xfertype, max;
331 struct usb_device *dev;
332 struct usb_host_endpoint *ep;
333 int is_out;
334 unsigned int allowed;
335
336 if (!urb || !urb->complete)
337 return -EINVAL;
338 if (urb->hcpriv) {
339 WARN_ONCE(1, "URB %p submitted while active\n", urb);
340 return -EBUSY;
341 }
342
343 dev = urb->dev;
344 if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED))
345 return -ENODEV;
346
347 /* For now, get the endpoint from the pipe. Eventually drivers
348 * will be required to set urb->ep directly and we will eliminate
349 * urb->pipe.
350 */
351 ep = usb_pipe_endpoint(dev, urb->pipe);
352 if (!ep)
353 return -ENOENT;
354
355 urb->ep = ep;
356 urb->status = -EINPROGRESS;
357 urb->actual_length = 0;
358
359 /* Lots of sanity checks, so HCDs can rely on clean data
360 * and don't need to duplicate tests
361 */
362 xfertype = usb_endpoint_type(&ep->desc);
363 if (xfertype == USB_ENDPOINT_XFER_CONTROL) {
364 struct usb_ctrlrequest *setup =
365 (struct usb_ctrlrequest *) urb->setup_packet;
366
367 if (!setup)
368 return -ENOEXEC;
369 is_out = !(setup->bRequestType & USB_DIR_IN) ||
370 !setup->wLength;
371 } else {
372 is_out = usb_endpoint_dir_out(&ep->desc);
373 }
374
375 /* Clear the internal flags and cache the direction for later use */
376 urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE |
377 URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL |
378 URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL |
379 URB_DMA_SG_COMBINED);
380 urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN);
381
382 if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
383 dev->state < USB_STATE_CONFIGURED)
384 return -ENODEV;
385
386 max = usb_endpoint_maxp(&ep->desc);
387 if (max <= 0) {
388 dev_dbg(&dev->dev,
389 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
390 usb_endpoint_num(&ep->desc), is_out ? "out" : "in",
391 __func__, max);
392 return -EMSGSIZE;
393 }
394
395 /* periodic transfers limit size per frame/uframe,
396 * but drivers only control those sizes for ISO.
397 * while we're checking, initialize return status.
398 */
399 if (xfertype == USB_ENDPOINT_XFER_ISOC) {
400 int n, len;
401
402 /* SuperSpeed isoc endpoints have up to 16 bursts of up to
403 * 3 packets each
404 */
405 if (dev->speed == USB_SPEED_SUPER) {
406 int burst = 1 + ep->ss_ep_comp.bMaxBurst;
407 int mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes);
408 max *= burst;
409 max *= mult;
410 }
411
412 /* "high bandwidth" mode, 1-3 packets/uframe? */
413 if (dev->speed == USB_SPEED_HIGH) {
414 int mult = 1 + ((max >> 11) & 0x03);
415 max &= 0x07ff;
416 max *= mult;
417 }
418
419 if (urb->number_of_packets <= 0)
420 return -EINVAL;
421 for (n = 0; n < urb->number_of_packets; n++) {
422 len = urb->iso_frame_desc[n].length;
423 if (len < 0 || len > max)
424 return -EMSGSIZE;
425 urb->iso_frame_desc[n].status = -EXDEV;
426 urb->iso_frame_desc[n].actual_length = 0;
427 }
428 } else if (urb->num_sgs && !urb->dev->bus->no_sg_constraint &&
429 dev->speed != USB_SPEED_WIRELESS) {
430 struct scatterlist *sg;
431 int i;
432
433 for_each_sg(urb->sg, sg, urb->num_sgs - 1, i)
434 if (sg->length % max)
435 return -EINVAL;
436 }
437
438 /* the I/O buffer must be mapped/unmapped, except when length=0 */
439 if (urb->transfer_buffer_length > INT_MAX)
440 return -EMSGSIZE;
441
442 /*
443 * stuff that drivers shouldn't do, but which shouldn't
444 * cause problems in HCDs if they get it wrong.
445 */
446
447 /* Check that the pipe's type matches the endpoint's type */
448 if (usb_pipetype(urb->pipe) != pipetypes[xfertype])
449 dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n",
450 usb_pipetype(urb->pipe), pipetypes[xfertype]);
451
452 /* Check against a simple/standard policy */
453 allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK |
454 URB_FREE_BUFFER);
455 switch (xfertype) {
456 case USB_ENDPOINT_XFER_BULK:
457 if (is_out)
458 allowed |= URB_ZERO_PACKET;
459 /* FALLTHROUGH */
460 case USB_ENDPOINT_XFER_CONTROL:
461 allowed |= URB_NO_FSBR; /* only affects UHCI */
462 /* FALLTHROUGH */
463 default: /* all non-iso endpoints */
464 if (!is_out)
465 allowed |= URB_SHORT_NOT_OK;
466 break;
467 case USB_ENDPOINT_XFER_ISOC:
468 allowed |= URB_ISO_ASAP;
469 break;
470 }
471 allowed &= urb->transfer_flags;
472
473 /* warn if submitter gave bogus flags */
474 if (allowed != urb->transfer_flags)
475 dev_WARN(&dev->dev, "BOGUS urb flags, %x --> %x\n",
476 urb->transfer_flags, allowed);
477
478 /*
479 * Force periodic transfer intervals to be legal values that are
480 * a power of two (so HCDs don't need to).
481 *
482 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
483 * supports different values... this uses EHCI/UHCI defaults (and
484 * EHCI can use smaller non-default values).
485 */
486 switch (xfertype) {
487 case USB_ENDPOINT_XFER_ISOC:
488 case USB_ENDPOINT_XFER_INT:
489 /* too small? */
490 switch (dev->speed) {
491 case USB_SPEED_WIRELESS:
492 if ((urb->interval < 6)
493 && (xfertype == USB_ENDPOINT_XFER_INT))
494 return -EINVAL;
495 default:
496 if (urb->interval <= 0)
497 return -EINVAL;
498 break;
499 }
500 /* too big? */
501 switch (dev->speed) {
502 case USB_SPEED_SUPER: /* units are 125us */
503 /* Handle up to 2^(16-1) microframes */
504 if (urb->interval > (1 << 15))
505 return -EINVAL;
506 max = 1 << 15;
507 break;
508 case USB_SPEED_WIRELESS:
509 if (urb->interval > 16)
510 return -EINVAL;
511 break;
512 case USB_SPEED_HIGH: /* units are microframes */
513 /* NOTE usb handles 2^15 */
514 if (urb->interval > (1024 * 8))
515 urb->interval = 1024 * 8;
516 max = 1024 * 8;
517 break;
518 case USB_SPEED_FULL: /* units are frames/msec */
519 case USB_SPEED_LOW:
520 if (xfertype == USB_ENDPOINT_XFER_INT) {
521 if (urb->interval > 255)
522 return -EINVAL;
523 /* NOTE ohci only handles up to 32 */
524 max = 128;
525 } else {
526 if (urb->interval > 1024)
527 urb->interval = 1024;
528 /* NOTE usb and ohci handle up to 2^15 */
529 max = 1024;
530 }
531 break;
532 default:
533 return -EINVAL;
534 }
535 if (dev->speed != USB_SPEED_WIRELESS) {
536 /* Round down to a power of 2, no more than max */
537 urb->interval = min(max, 1 << ilog2(urb->interval));
538 }
539 }
540
541 return usb_hcd_submit_urb(urb, mem_flags);
542}
543EXPORT_SYMBOL_GPL(usb_submit_urb);
544
545/*-------------------------------------------------------------------*/
546
547/**
548 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
549 * @urb: pointer to urb describing a previously submitted request,
550 * may be NULL
551 *
552 * This routine cancels an in-progress request. URBs complete only once
553 * per submission, and may be canceled only once per submission.
554 * Successful cancellation means termination of @urb will be expedited
555 * and the completion handler will be called with a status code
556 * indicating that the request has been canceled (rather than any other
557 * code).
558 *
559 * Drivers should not call this routine or related routines, such as
560 * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect
561 * method has returned. The disconnect function should synchronize with
562 * a driver's I/O routines to insure that all URB-related activity has
563 * completed before it returns.
564 *
565 * This request is asynchronous, however the HCD might call the ->complete()
566 * callback during unlink. Therefore when drivers call usb_unlink_urb(), they
567 * must not hold any locks that may be taken by the completion function.
568 * Success is indicated by returning -EINPROGRESS, at which time the URB will
569 * probably not yet have been given back to the device driver. When it is
570 * eventually called, the completion function will see @urb->status ==
571 * -ECONNRESET.
572 * Failure is indicated by usb_unlink_urb() returning any other value.
573 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
574 * never submitted, or it was unlinked before, or the hardware is already
575 * finished with it), even if the completion handler has not yet run.
576 *
577 * The URB must not be deallocated while this routine is running. In
578 * particular, when a driver calls this routine, it must insure that the
579 * completion handler cannot deallocate the URB.
580 *
581 * Return: -EINPROGRESS on success. See description for other values on
582 * failure.
583 *
584 * Unlinking and Endpoint Queues:
585 *
586 * [The behaviors and guarantees described below do not apply to virtual
587 * root hubs but only to endpoint queues for physical USB devices.]
588 *
589 * Host Controller Drivers (HCDs) place all the URBs for a particular
590 * endpoint in a queue. Normally the queue advances as the controller
591 * hardware processes each request. But when an URB terminates with an
592 * error its queue generally stops (see below), at least until that URB's
593 * completion routine returns. It is guaranteed that a stopped queue
594 * will not restart until all its unlinked URBs have been fully retired,
595 * with their completion routines run, even if that's not until some time
596 * after the original completion handler returns. The same behavior and
597 * guarantee apply when an URB terminates because it was unlinked.
598 *
599 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
600 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
601 * and -EREMOTEIO. Control endpoint queues behave the same way except
602 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
603 * for isochronous endpoints are treated differently, because they must
604 * advance at fixed rates. Such queues do not stop when an URB
605 * encounters an error or is unlinked. An unlinked isochronous URB may
606 * leave a gap in the stream of packets; it is undefined whether such
607 * gaps can be filled in.
608 *
609 * Note that early termination of an URB because a short packet was
610 * received will generate a -EREMOTEIO error if and only if the
611 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
612 * drivers can build deep queues for large or complex bulk transfers
613 * and clean them up reliably after any sort of aborted transfer by
614 * unlinking all pending URBs at the first fault.
615 *
616 * When a control URB terminates with an error other than -EREMOTEIO, it
617 * is quite likely that the status stage of the transfer will not take
618 * place.
619 */
620int usb_unlink_urb(struct urb *urb)
621{
622 if (!urb)
623 return -EINVAL;
624 if (!urb->dev)
625 return -ENODEV;
626 if (!urb->ep)
627 return -EIDRM;
628 return usb_hcd_unlink_urb(urb, -ECONNRESET);
629}
630EXPORT_SYMBOL_GPL(usb_unlink_urb);
631
632/**
633 * usb_kill_urb - cancel a transfer request and wait for it to finish
634 * @urb: pointer to URB describing a previously submitted request,
635 * may be NULL
636 *
637 * This routine cancels an in-progress request. It is guaranteed that
638 * upon return all completion handlers will have finished and the URB
639 * will be totally idle and available for reuse. These features make
640 * this an ideal way to stop I/O in a disconnect() callback or close()
641 * function. If the request has not already finished or been unlinked
642 * the completion handler will see urb->status == -ENOENT.
643 *
644 * While the routine is running, attempts to resubmit the URB will fail
645 * with error -EPERM. Thus even if the URB's completion handler always
646 * tries to resubmit, it will not succeed and the URB will become idle.
647 *
648 * The URB must not be deallocated while this routine is running. In
649 * particular, when a driver calls this routine, it must insure that the
650 * completion handler cannot deallocate the URB.
651 *
652 * This routine may not be used in an interrupt context (such as a bottom
653 * half or a completion handler), or when holding a spinlock, or in other
654 * situations where the caller can't schedule().
655 *
656 * This routine should not be called by a driver after its disconnect
657 * method has returned.
658 */
659void usb_kill_urb(struct urb *urb)
660{
661 might_sleep();
662 if (!(urb && urb->dev && urb->ep))
663 return;
664 atomic_inc(&urb->reject);
665
666 usb_hcd_unlink_urb(urb, -ENOENT);
667 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
668
669 atomic_dec(&urb->reject);
670}
671EXPORT_SYMBOL_GPL(usb_kill_urb);
672
673/**
674 * usb_poison_urb - reliably kill a transfer and prevent further use of an URB
675 * @urb: pointer to URB describing a previously submitted request,
676 * may be NULL
677 *
678 * This routine cancels an in-progress request. It is guaranteed that
679 * upon return all completion handlers will have finished and the URB
680 * will be totally idle and cannot be reused. These features make
681 * this an ideal way to stop I/O in a disconnect() callback.
682 * If the request has not already finished or been unlinked
683 * the completion handler will see urb->status == -ENOENT.
684 *
685 * After and while the routine runs, attempts to resubmit the URB will fail
686 * with error -EPERM. Thus even if the URB's completion handler always
687 * tries to resubmit, it will not succeed and the URB will become idle.
688 *
689 * The URB must not be deallocated while this routine is running. In
690 * particular, when a driver calls this routine, it must insure that the
691 * completion handler cannot deallocate the URB.
692 *
693 * This routine may not be used in an interrupt context (such as a bottom
694 * half or a completion handler), or when holding a spinlock, or in other
695 * situations where the caller can't schedule().
696 *
697 * This routine should not be called by a driver after its disconnect
698 * method has returned.
699 */
700void usb_poison_urb(struct urb *urb)
701{
702 might_sleep();
703 if (!urb)
704 return;
705 atomic_inc(&urb->reject);
706
707 if (!urb->dev || !urb->ep)
708 return;
709
710 usb_hcd_unlink_urb(urb, -ENOENT);
711 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
712}
713EXPORT_SYMBOL_GPL(usb_poison_urb);
714
715void usb_unpoison_urb(struct urb *urb)
716{
717 if (!urb)
718 return;
719
720 atomic_dec(&urb->reject);
721}
722EXPORT_SYMBOL_GPL(usb_unpoison_urb);
723
724/**
725 * usb_block_urb - reliably prevent further use of an URB
726 * @urb: pointer to URB to be blocked, may be NULL
727 *
728 * After the routine has run, attempts to resubmit the URB will fail
729 * with error -EPERM. Thus even if the URB's completion handler always
730 * tries to resubmit, it will not succeed and the URB will become idle.
731 *
732 * The URB must not be deallocated while this routine is running. In
733 * particular, when a driver calls this routine, it must insure that the
734 * completion handler cannot deallocate the URB.
735 */
736void usb_block_urb(struct urb *urb)
737{
738 if (!urb)
739 return;
740
741 atomic_inc(&urb->reject);
742}
743EXPORT_SYMBOL_GPL(usb_block_urb);
744
745/**
746 * usb_kill_anchored_urbs - cancel transfer requests en masse
747 * @anchor: anchor the requests are bound to
748 *
749 * this allows all outstanding URBs to be killed starting
750 * from the back of the queue
751 *
752 * This routine should not be called by a driver after its disconnect
753 * method has returned.
754 */
755void usb_kill_anchored_urbs(struct usb_anchor *anchor)
756{
757 struct urb *victim;
758
759 spin_lock_irq(&anchor->lock);
760 while (!list_empty(&anchor->urb_list)) {
761 victim = list_entry(anchor->urb_list.prev, struct urb,
762 anchor_list);
763 /* we must make sure the URB isn't freed before we kill it*/
764 usb_get_urb(victim);
765 spin_unlock_irq(&anchor->lock);
766 /* this will unanchor the URB */
767 usb_kill_urb(victim);
768 usb_put_urb(victim);
769 spin_lock_irq(&anchor->lock);
770 }
771 spin_unlock_irq(&anchor->lock);
772}
773EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs);
774
775
776/**
777 * usb_poison_anchored_urbs - cease all traffic from an anchor
778 * @anchor: anchor the requests are bound to
779 *
780 * this allows all outstanding URBs to be poisoned starting
781 * from the back of the queue. Newly added URBs will also be
782 * poisoned
783 *
784 * This routine should not be called by a driver after its disconnect
785 * method has returned.
786 */
787void usb_poison_anchored_urbs(struct usb_anchor *anchor)
788{
789 struct urb *victim;
790
791 spin_lock_irq(&anchor->lock);
792 anchor->poisoned = 1;
793 while (!list_empty(&anchor->urb_list)) {
794 victim = list_entry(anchor->urb_list.prev, struct urb,
795 anchor_list);
796 /* we must make sure the URB isn't freed before we kill it*/
797 usb_get_urb(victim);
798 spin_unlock_irq(&anchor->lock);
799 /* this will unanchor the URB */
800 usb_poison_urb(victim);
801 usb_put_urb(victim);
802 spin_lock_irq(&anchor->lock);
803 }
804 spin_unlock_irq(&anchor->lock);
805}
806EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs);
807
808/**
809 * usb_unpoison_anchored_urbs - let an anchor be used successfully again
810 * @anchor: anchor the requests are bound to
811 *
812 * Reverses the effect of usb_poison_anchored_urbs
813 * the anchor can be used normally after it returns
814 */
815void usb_unpoison_anchored_urbs(struct usb_anchor *anchor)
816{
817 unsigned long flags;
818 struct urb *lazarus;
819
820 spin_lock_irqsave(&anchor->lock, flags);
821 list_for_each_entry(lazarus, &anchor->urb_list, anchor_list) {
822 usb_unpoison_urb(lazarus);
823 }
824 anchor->poisoned = 0;
825 spin_unlock_irqrestore(&anchor->lock, flags);
826}
827EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs);
828/**
829 * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse
830 * @anchor: anchor the requests are bound to
831 *
832 * this allows all outstanding URBs to be unlinked starting
833 * from the back of the queue. This function is asynchronous.
834 * The unlinking is just triggered. It may happen after this
835 * function has returned.
836 *
837 * This routine should not be called by a driver after its disconnect
838 * method has returned.
839 */
840void usb_unlink_anchored_urbs(struct usb_anchor *anchor)
841{
842 struct urb *victim;
843
844 while ((victim = usb_get_from_anchor(anchor)) != NULL) {
845 usb_unlink_urb(victim);
846 usb_put_urb(victim);
847 }
848}
849EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs);
850
851/**
852 * usb_anchor_suspend_wakeups
853 * @anchor: the anchor you want to suspend wakeups on
854 *
855 * Call this to stop the last urb being unanchored from waking up any
856 * usb_wait_anchor_empty_timeout waiters. This is used in the hcd urb give-
857 * back path to delay waking up until after the completion handler has run.
858 */
859void usb_anchor_suspend_wakeups(struct usb_anchor *anchor)
860{
861 if (anchor)
862 atomic_inc(&anchor->suspend_wakeups);
863}
864EXPORT_SYMBOL_GPL(usb_anchor_suspend_wakeups);
865
866/**
867 * usb_anchor_resume_wakeups
868 * @anchor: the anchor you want to resume wakeups on
869 *
870 * Allow usb_wait_anchor_empty_timeout waiters to be woken up again, and
871 * wake up any current waiters if the anchor is empty.
872 */
873void usb_anchor_resume_wakeups(struct usb_anchor *anchor)
874{
875 if (!anchor)
876 return;
877
878 atomic_dec(&anchor->suspend_wakeups);
879 if (usb_anchor_check_wakeup(anchor))
880 wake_up(&anchor->wait);
881}
882EXPORT_SYMBOL_GPL(usb_anchor_resume_wakeups);
883
884/**
885 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
886 * @anchor: the anchor you want to become unused
887 * @timeout: how long you are willing to wait in milliseconds
888 *
889 * Call this is you want to be sure all an anchor's
890 * URBs have finished
891 *
892 * Return: Non-zero if the anchor became unused. Zero on timeout.
893 */
894int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
895 unsigned int timeout)
896{
897 return wait_event_timeout(anchor->wait,
898 usb_anchor_check_wakeup(anchor),
899 msecs_to_jiffies(timeout));
900}
901EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout);
902
903/**
904 * usb_get_from_anchor - get an anchor's oldest urb
905 * @anchor: the anchor whose urb you want
906 *
907 * This will take the oldest urb from an anchor,
908 * unanchor and return it
909 *
910 * Return: The oldest urb from @anchor, or %NULL if @anchor has no
911 * urbs associated with it.
912 */
913struct urb *usb_get_from_anchor(struct usb_anchor *anchor)
914{
915 struct urb *victim;
916 unsigned long flags;
917
918 spin_lock_irqsave(&anchor->lock, flags);
919 if (!list_empty(&anchor->urb_list)) {
920 victim = list_entry(anchor->urb_list.next, struct urb,
921 anchor_list);
922 usb_get_urb(victim);
923 __usb_unanchor_urb(victim, anchor);
924 } else {
925 victim = NULL;
926 }
927 spin_unlock_irqrestore(&anchor->lock, flags);
928
929 return victim;
930}
931
932EXPORT_SYMBOL_GPL(usb_get_from_anchor);
933
934/**
935 * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs
936 * @anchor: the anchor whose urbs you want to unanchor
937 *
938 * use this to get rid of all an anchor's urbs
939 */
940void usb_scuttle_anchored_urbs(struct usb_anchor *anchor)
941{
942 struct urb *victim;
943 unsigned long flags;
944
945 spin_lock_irqsave(&anchor->lock, flags);
946 while (!list_empty(&anchor->urb_list)) {
947 victim = list_entry(anchor->urb_list.prev, struct urb,
948 anchor_list);
949 __usb_unanchor_urb(victim, anchor);
950 }
951 spin_unlock_irqrestore(&anchor->lock, flags);
952}
953
954EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs);
955
956/**
957 * usb_anchor_empty - is an anchor empty
958 * @anchor: the anchor you want to query
959 *
960 * Return: 1 if the anchor has no urbs associated with it.
961 */
962int usb_anchor_empty(struct usb_anchor *anchor)
963{
964 return list_empty(&anchor->urb_list);
965}
966
967EXPORT_SYMBOL_GPL(usb_anchor_empty);
968