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 void urb_destroy(struct kref
*kref
)
15 struct urb
*urb
= to_urb(kref
);
17 if (urb
->transfer_flags
& URB_FREE_BUFFER
)
18 kfree(urb
->transfer_buffer
);
24 * usb_init_urb - initializes a urb so that it can be used by a USB driver
25 * @urb: pointer to the urb to initialize
27 * Initializes a urb so that the USB subsystem can use it properly.
29 * If a urb is created with a call to usb_alloc_urb() it is not
30 * necessary to call this function. Only use this if you allocate the
31 * space for a struct urb on your own. If you call this function, be
32 * careful when freeing the memory for your urb that it is no longer in
33 * use by the USB core.
35 * Only use this function if you _really_ understand what you are doing.
37 void usb_init_urb(struct urb
*urb
)
40 memset(urb
, 0, sizeof(*urb
));
41 kref_init(&urb
->kref
);
42 INIT_LIST_HEAD(&urb
->anchor_list
);
45 EXPORT_SYMBOL_GPL(usb_init_urb
);
48 * usb_alloc_urb - creates a new urb for a USB driver to use
49 * @iso_packets: number of iso packets for this urb
50 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
51 * valid options for this.
53 * Creates an urb for the USB driver to use, initializes a few internal
54 * structures, incrementes the usage counter, and returns a pointer to it.
56 * If no memory is available, NULL is returned.
58 * If the driver want to use this urb for interrupt, control, or bulk
59 * endpoints, pass '0' as the number of iso packets.
61 * The driver must call usb_free_urb() when it is finished with the urb.
63 struct urb
*usb_alloc_urb(int iso_packets
, gfp_t mem_flags
)
67 urb
= kmalloc(sizeof(struct urb
) +
68 iso_packets
* sizeof(struct usb_iso_packet_descriptor
),
71 err("alloc_urb: kmalloc failed");
77 EXPORT_SYMBOL_GPL(usb_alloc_urb
);
80 * usb_free_urb - frees the memory used by a urb when all users of it are finished
81 * @urb: pointer to the urb to free, may be NULL
83 * Must be called when a user of a urb is finished with it. When the last user
84 * of the urb calls this function, the memory of the urb is freed.
86 * Note: The transfer buffer associated with the urb is not freed, that must be
89 void usb_free_urb(struct urb
*urb
)
92 kref_put(&urb
->kref
, urb_destroy
);
94 EXPORT_SYMBOL_GPL(usb_free_urb
);
97 * usb_get_urb - increments the reference count of the urb
98 * @urb: pointer to the urb to modify, may be NULL
100 * This must be called whenever a urb is transferred from a device driver to a
101 * host controller driver. This allows proper reference counting to happen
104 * A pointer to the urb with the incremented reference counter is returned.
106 struct urb
* usb_get_urb(struct urb
*urb
)
109 kref_get(&urb
->kref
);
112 EXPORT_SYMBOL_GPL(usb_get_urb
);
115 * usb_anchor_urb - anchors an URB while it is processed
116 * @urb: pointer to the urb to anchor
117 * @anchor: pointer to the anchor
119 * This can be called to have access to URBs which are to be executed
120 * without bothering to track them
122 void usb_anchor_urb(struct urb
*urb
, struct usb_anchor
*anchor
)
126 spin_lock_irqsave(&anchor
->lock
, flags
);
128 list_add_tail(&urb
->anchor_list
, &anchor
->urb_list
);
129 urb
->anchor
= anchor
;
130 spin_unlock_irqrestore(&anchor
->lock
, flags
);
132 EXPORT_SYMBOL_GPL(usb_anchor_urb
);
135 * usb_unanchor_urb - unanchors an URB
136 * @urb: pointer to the urb to anchor
138 * Call this to stop the system keeping track of this URB
140 void usb_unanchor_urb(struct urb
*urb
)
143 struct usb_anchor
*anchor
;
148 anchor
= urb
->anchor
;
152 spin_lock_irqsave(&anchor
->lock
, flags
);
153 if (unlikely(anchor
!= urb
->anchor
)) {
154 /* we've lost the race to another thread */
155 spin_unlock_irqrestore(&anchor
->lock
, flags
);
159 list_del(&urb
->anchor_list
);
160 spin_unlock_irqrestore(&anchor
->lock
, flags
);
162 if (list_empty(&anchor
->urb_list
))
163 wake_up(&anchor
->wait
);
165 EXPORT_SYMBOL_GPL(usb_unanchor_urb
);
167 /*-------------------------------------------------------------------*/
170 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
171 * @urb: pointer to the urb describing the request
172 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
173 * of valid options for this.
175 * This submits a transfer request, and transfers control of the URB
176 * describing that request to the USB subsystem. Request completion will
177 * be indicated later, asynchronously, by calling the completion handler.
178 * The three types of completion are success, error, and unlink
179 * (a software-induced fault, also called "request cancellation").
181 * URBs may be submitted in interrupt context.
183 * The caller must have correctly initialized the URB before submitting
184 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
185 * available to ensure that most fields are correctly initialized, for
186 * the particular kind of transfer, although they will not initialize
187 * any transfer flags.
189 * Successful submissions return 0; otherwise this routine returns a
190 * negative error number. If the submission is successful, the complete()
191 * callback from the URB will be called exactly once, when the USB core and
192 * Host Controller Driver (HCD) are finished with the URB. When the completion
193 * function is called, control of the URB is returned to the device
194 * driver which issued the request. The completion handler may then
195 * immediately free or reuse that URB.
197 * With few exceptions, USB device drivers should never access URB fields
198 * provided by usbcore or the HCD until its complete() is called.
199 * The exceptions relate to periodic transfer scheduling. For both
200 * interrupt and isochronous urbs, as part of successful URB submission
201 * urb->interval is modified to reflect the actual transfer period used
202 * (normally some power of two units). And for isochronous urbs,
203 * urb->start_frame is modified to reflect when the URB's transfers were
204 * scheduled to start. Not all isochronous transfer scheduling policies
205 * will work, but most host controller drivers should easily handle ISO
206 * queues going from now until 10-200 msec into the future.
208 * For control endpoints, the synchronous usb_control_msg() call is
209 * often used (in non-interrupt context) instead of this call.
210 * That is often used through convenience wrappers, for the requests
211 * that are standardized in the USB 2.0 specification. For bulk
212 * endpoints, a synchronous usb_bulk_msg() call is available.
216 * URBs may be submitted to endpoints before previous ones complete, to
217 * minimize the impact of interrupt latencies and system overhead on data
218 * throughput. With that queuing policy, an endpoint's queue would never
219 * be empty. This is required for continuous isochronous data streams,
220 * and may also be required for some kinds of interrupt transfers. Such
221 * queuing also maximizes bandwidth utilization by letting USB controllers
222 * start work on later requests before driver software has finished the
223 * completion processing for earlier (successful) requests.
225 * As of Linux 2.6, all USB endpoint transfer queues support depths greater
226 * than one. This was previously a HCD-specific behavior, except for ISO
227 * transfers. Non-isochronous endpoint queues are inactive during cleanup
228 * after faults (transfer errors or cancellation).
230 * Reserved Bandwidth Transfers:
232 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
233 * using the interval specified in the urb. Submitting the first urb to
234 * the endpoint reserves the bandwidth necessary to make those transfers.
235 * If the USB subsystem can't allocate sufficient bandwidth to perform
236 * the periodic request, submitting such a periodic request should fail.
238 * Device drivers must explicitly request that repetition, by ensuring that
239 * some URB is always on the endpoint's queue (except possibly for short
240 * periods during completion callacks). When there is no longer an urb
241 * queued, the endpoint's bandwidth reservation is canceled. This means
242 * drivers can use their completion handlers to ensure they keep bandwidth
243 * they need, by reinitializing and resubmitting the just-completed urb
244 * until the driver longer needs that periodic bandwidth.
248 * The general rules for how to decide which mem_flags to use
249 * are the same as for kmalloc. There are four
250 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
253 * GFP_NOFS is not ever used, as it has not been implemented yet.
255 * GFP_ATOMIC is used when
256 * (a) you are inside a completion handler, an interrupt, bottom half,
257 * tasklet or timer, or
258 * (b) you are holding a spinlock or rwlock (does not apply to
260 * (c) current->state != TASK_RUNNING, this is the case only after
263 * GFP_NOIO is used in the block io path and error handling of storage
266 * All other situations use GFP_KERNEL.
268 * Some more specific rules for mem_flags can be inferred, such as
269 * (1) start_xmit, timeout, and receive methods of network drivers must
270 * use GFP_ATOMIC (they are called with a spinlock held);
271 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
272 * called with a spinlock held);
273 * (3) If you use a kernel thread with a network driver you must use
274 * GFP_NOIO, unless (b) or (c) apply;
275 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
276 * apply or your are in a storage driver's block io path;
277 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
278 * (6) changing firmware on a running storage or net device uses
279 * GFP_NOIO, unless b) or c) apply
282 int usb_submit_urb(struct urb
*urb
, gfp_t mem_flags
)
285 struct usb_device
*dev
;
286 struct usb_host_endpoint
*ep
;
289 if (!urb
|| urb
->hcpriv
|| !urb
->complete
)
291 if (!(dev
= urb
->dev
) || dev
->state
< USB_STATE_DEFAULT
)
294 /* For now, get the endpoint from the pipe. Eventually drivers
295 * will be required to set urb->ep directly and we will eliminate
298 ep
= (usb_pipein(urb
->pipe
) ? dev
->ep_in
: dev
->ep_out
)
299 [usb_pipeendpoint(urb
->pipe
)];
304 urb
->status
= -EINPROGRESS
;
305 urb
->actual_length
= 0;
307 /* Lots of sanity checks, so HCDs can rely on clean data
308 * and don't need to duplicate tests
310 xfertype
= usb_endpoint_type(&ep
->desc
);
311 if (xfertype
== USB_ENDPOINT_XFER_CONTROL
) {
312 struct usb_ctrlrequest
*setup
=
313 (struct usb_ctrlrequest
*) urb
->setup_packet
;
317 is_out
= !(setup
->bRequestType
& USB_DIR_IN
) ||
320 is_out
= usb_endpoint_dir_out(&ep
->desc
);
323 /* Cache the direction for later use */
324 urb
->transfer_flags
= (urb
->transfer_flags
& ~URB_DIR_MASK
) |
325 (is_out
? URB_DIR_OUT
: URB_DIR_IN
);
327 if (xfertype
!= USB_ENDPOINT_XFER_CONTROL
&&
328 dev
->state
< USB_STATE_CONFIGURED
)
331 max
= le16_to_cpu(ep
->desc
.wMaxPacketSize
);
334 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
335 usb_endpoint_num(&ep
->desc
), is_out
? "out" : "in",
340 /* periodic transfers limit size per frame/uframe,
341 * but drivers only control those sizes for ISO.
342 * while we're checking, initialize return status.
344 if (xfertype
== USB_ENDPOINT_XFER_ISOC
) {
347 /* "high bandwidth" mode, 1-3 packets/uframe? */
348 if (dev
->speed
== USB_SPEED_HIGH
) {
349 int mult
= 1 + ((max
>> 11) & 0x03);
354 if (urb
->number_of_packets
<= 0)
356 for (n
= 0; n
< urb
->number_of_packets
; n
++) {
357 len
= urb
->iso_frame_desc
[n
].length
;
358 if (len
< 0 || len
> max
)
360 urb
->iso_frame_desc
[n
].status
= -EXDEV
;
361 urb
->iso_frame_desc
[n
].actual_length
= 0;
365 /* the I/O buffer must be mapped/unmapped, except when length=0 */
366 if (urb
->transfer_buffer_length
< 0)
370 /* stuff that drivers shouldn't do, but which shouldn't
371 * cause problems in HCDs if they get it wrong.
374 unsigned int orig_flags
= urb
->transfer_flags
;
375 unsigned int allowed
;
377 /* enforce simple/standard policy */
378 allowed
= (URB_NO_TRANSFER_DMA_MAP
| URB_NO_SETUP_DMA_MAP
|
379 URB_NO_INTERRUPT
| URB_DIR_MASK
| URB_FREE_BUFFER
);
381 case USB_ENDPOINT_XFER_BULK
:
383 allowed
|= URB_ZERO_PACKET
;
385 case USB_ENDPOINT_XFER_CONTROL
:
386 allowed
|= URB_NO_FSBR
; /* only affects UHCI */
388 default: /* all non-iso endpoints */
390 allowed
|= URB_SHORT_NOT_OK
;
392 case USB_ENDPOINT_XFER_ISOC
:
393 allowed
|= URB_ISO_ASAP
;
396 urb
->transfer_flags
&= allowed
;
398 /* fail if submitter gave bogus flags */
399 if (urb
->transfer_flags
!= orig_flags
) {
400 err("BOGUS urb flags, %x --> %x",
401 orig_flags
, urb
->transfer_flags
);
407 * Force periodic transfer intervals to be legal values that are
408 * a power of two (so HCDs don't need to).
410 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
411 * supports different values... this uses EHCI/UHCI defaults (and
412 * EHCI can use smaller non-default values).
415 case USB_ENDPOINT_XFER_ISOC
:
416 case USB_ENDPOINT_XFER_INT
:
418 if (urb
->interval
<= 0)
421 switch (dev
->speed
) {
422 case USB_SPEED_HIGH
: /* units are microframes */
423 // NOTE usb handles 2^15
424 if (urb
->interval
> (1024 * 8))
425 urb
->interval
= 1024 * 8;
428 case USB_SPEED_FULL
: /* units are frames/msec */
430 if (xfertype
== USB_ENDPOINT_XFER_INT
) {
431 if (urb
->interval
> 255)
433 // NOTE ohci only handles up to 32
436 if (urb
->interval
> 1024)
437 urb
->interval
= 1024;
438 // NOTE usb and ohci handle up to 2^15
445 /* Round down to a power of 2, no more than max */
446 urb
->interval
= min(max
, 1 << ilog2(urb
->interval
));
449 return usb_hcd_submit_urb(urb
, mem_flags
);
451 EXPORT_SYMBOL_GPL(usb_submit_urb
);
453 /*-------------------------------------------------------------------*/
456 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
457 * @urb: pointer to urb describing a previously submitted request,
460 * This routine cancels an in-progress request. URBs complete only once
461 * per submission, and may be canceled only once per submission.
462 * Successful cancellation means termination of @urb will be expedited
463 * and the completion handler will be called with a status code
464 * indicating that the request has been canceled (rather than any other
467 * This request is always asynchronous. Success is indicated by
468 * returning -EINPROGRESS, at which time the URB will probably not yet
469 * have been given back to the device driver. When it is eventually
470 * called, the completion function will see @urb->status == -ECONNRESET.
471 * Failure is indicated by usb_unlink_urb() returning any other value.
472 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
473 * never submitted, or it was unlinked before, or the hardware is already
474 * finished with it), even if the completion handler has not yet run.
476 * Unlinking and Endpoint Queues:
478 * [The behaviors and guarantees described below do not apply to virtual
479 * root hubs but only to endpoint queues for physical USB devices.]
481 * Host Controller Drivers (HCDs) place all the URBs for a particular
482 * endpoint in a queue. Normally the queue advances as the controller
483 * hardware processes each request. But when an URB terminates with an
484 * error its queue generally stops (see below), at least until that URB's
485 * completion routine returns. It is guaranteed that a stopped queue
486 * will not restart until all its unlinked URBs have been fully retired,
487 * with their completion routines run, even if that's not until some time
488 * after the original completion handler returns. The same behavior and
489 * guarantee apply when an URB terminates because it was unlinked.
491 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
492 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
493 * and -EREMOTEIO. Control endpoint queues behave the same way except
494 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
495 * for isochronous endpoints are treated differently, because they must
496 * advance at fixed rates. Such queues do not stop when an URB
497 * encounters an error or is unlinked. An unlinked isochronous URB may
498 * leave a gap in the stream of packets; it is undefined whether such
499 * gaps can be filled in.
501 * Note that early termination of an URB because a short packet was
502 * received will generate a -EREMOTEIO error if and only if the
503 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
504 * drivers can build deep queues for large or complex bulk transfers
505 * and clean them up reliably after any sort of aborted transfer by
506 * unlinking all pending URBs at the first fault.
508 * When a control URB terminates with an error other than -EREMOTEIO, it
509 * is quite likely that the status stage of the transfer will not take
512 int usb_unlink_urb(struct urb
*urb
)
520 return usb_hcd_unlink_urb(urb
, -ECONNRESET
);
522 EXPORT_SYMBOL_GPL(usb_unlink_urb
);
525 * usb_kill_urb - cancel a transfer request and wait for it to finish
526 * @urb: pointer to URB describing a previously submitted request,
529 * This routine cancels an in-progress request. It is guaranteed that
530 * upon return all completion handlers will have finished and the URB
531 * will be totally idle and available for reuse. These features make
532 * this an ideal way to stop I/O in a disconnect() callback or close()
533 * function. If the request has not already finished or been unlinked
534 * the completion handler will see urb->status == -ENOENT.
536 * While the routine is running, attempts to resubmit the URB will fail
537 * with error -EPERM. Thus even if the URB's completion handler always
538 * tries to resubmit, it will not succeed and the URB will become idle.
540 * This routine may not be used in an interrupt context (such as a bottom
541 * half or a completion handler), or when holding a spinlock, or in other
542 * situations where the caller can't schedule().
544 void usb_kill_urb(struct urb
*urb
)
546 static DEFINE_MUTEX(reject_mutex
);
549 if (!(urb
&& urb
->dev
&& urb
->ep
))
551 mutex_lock(&reject_mutex
);
553 mutex_unlock(&reject_mutex
);
555 usb_hcd_unlink_urb(urb
, -ENOENT
);
556 wait_event(usb_kill_urb_queue
, atomic_read(&urb
->use_count
) == 0);
558 mutex_lock(&reject_mutex
);
560 mutex_unlock(&reject_mutex
);
562 EXPORT_SYMBOL_GPL(usb_kill_urb
);
565 * usb_kill_anchored_urbs - cancel transfer requests en masse
566 * @anchor: anchor the requests are bound to
568 * this allows all outstanding URBs to be killed starting
569 * from the back of the queue
571 void usb_kill_anchored_urbs(struct usb_anchor
*anchor
)
575 spin_lock_irq(&anchor
->lock
);
576 while (!list_empty(&anchor
->urb_list
)) {
577 victim
= list_entry(anchor
->urb_list
.prev
, struct urb
, anchor_list
);
578 /* we must make sure the URB isn't freed before we kill it*/
580 spin_unlock_irq(&anchor
->lock
);
581 /* this will unanchor the URB */
582 usb_kill_urb(victim
);
584 spin_lock_irq(&anchor
->lock
);
586 spin_unlock_irq(&anchor
->lock
);
588 EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs
);
591 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
592 * @anchor: the anchor you want to become unused
593 * @timeout: how long you are willing to wait in milliseconds
595 * Call this is you want to be sure all an anchor's
598 int usb_wait_anchor_empty_timeout(struct usb_anchor
*anchor
,
599 unsigned int timeout
)
601 return wait_event_timeout(anchor
->wait
, list_empty(&anchor
->urb_list
),
602 msecs_to_jiffies(timeout
));
604 EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout
);