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>
7 #include <linux/wait.h>
10 #define to_urb(d) container_of(d, struct urb, kref)
12 static void urb_destroy(struct kref
*kref
)
14 struct urb
*urb
= to_urb(kref
);
16 if (urb
->transfer_flags
& URB_FREE_BUFFER
)
17 kfree(urb
->transfer_buffer
);
23 * usb_init_urb - initializes a urb so that it can be used by a USB driver
24 * @urb: pointer to the urb to initialize
26 * Initializes a urb so that the USB subsystem can use it properly.
28 * If a urb is created with a call to usb_alloc_urb() it is not
29 * necessary to call this function. Only use this if you allocate the
30 * space for a struct urb on your own. If you call this function, be
31 * careful when freeing the memory for your urb that it is no longer in
32 * use by the USB core.
34 * Only use this function if you _really_ understand what you are doing.
36 void usb_init_urb(struct urb
*urb
)
39 memset(urb
, 0, sizeof(*urb
));
40 kref_init(&urb
->kref
);
41 spin_lock_init(&urb
->lock
);
42 INIT_LIST_HEAD(&urb
->anchor_list
);
47 * usb_alloc_urb - creates a new urb for a USB driver to use
48 * @iso_packets: number of iso packets for this urb
49 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
50 * valid options for this.
52 * Creates an urb for the USB driver to use, initializes a few internal
53 * structures, incrementes the usage counter, and returns a pointer to it.
55 * If no memory is available, NULL is returned.
57 * If the driver want to use this urb for interrupt, control, or bulk
58 * endpoints, pass '0' as the number of iso packets.
60 * The driver must call usb_free_urb() when it is finished with the urb.
62 struct urb
*usb_alloc_urb(int iso_packets
, gfp_t mem_flags
)
66 urb
= kmalloc(sizeof(struct urb
) +
67 iso_packets
* sizeof(struct usb_iso_packet_descriptor
),
70 err("alloc_urb: kmalloc failed");
78 * usb_free_urb - frees the memory used by a urb when all users of it are finished
79 * @urb: pointer to the urb to free, may be NULL
81 * Must be called when a user of a urb is finished with it. When the last user
82 * of the urb calls this function, the memory of the urb is freed.
84 * Note: The transfer buffer associated with the urb is not freed, that must be
87 void usb_free_urb(struct urb
*urb
)
90 kref_put(&urb
->kref
, urb_destroy
);
94 * usb_get_urb - increments the reference count of the urb
95 * @urb: pointer to the urb to modify, may be NULL
97 * This must be called whenever a urb is transferred from a device driver to a
98 * host controller driver. This allows proper reference counting to happen
101 * A pointer to the urb with the incremented reference counter is returned.
103 struct urb
* usb_get_urb(struct urb
*urb
)
106 kref_get(&urb
->kref
);
111 * usb_anchor_urb - anchors an URB while it is processed
112 * @urb: pointer to the urb to anchor
113 * @anchor: pointer to the anchor
115 * This can be called to have access to URBs which are to be executed
116 * without bothering to track them
118 void usb_anchor_urb(struct urb
*urb
, struct usb_anchor
*anchor
)
122 spin_lock_irqsave(&anchor
->lock
, flags
);
124 list_add_tail(&urb
->anchor_list
, &anchor
->urb_list
);
125 urb
->anchor
= anchor
;
126 spin_unlock_irqrestore(&anchor
->lock
, flags
);
128 EXPORT_SYMBOL_GPL(usb_anchor_urb
);
131 * usb_unanchor_urb - unanchors an URB
132 * @urb: pointer to the urb to anchor
134 * Call this to stop the system keeping track of this URB
136 void usb_unanchor_urb(struct urb
*urb
)
139 struct usb_anchor
*anchor
;
144 anchor
= urb
->anchor
;
148 spin_lock_irqsave(&anchor
->lock
, flags
);
149 if (unlikely(anchor
!= urb
->anchor
)) {
150 /* we've lost the race to another thread */
151 spin_unlock_irqrestore(&anchor
->lock
, flags
);
155 list_del(&urb
->anchor_list
);
156 spin_unlock_irqrestore(&anchor
->lock
, flags
);
158 if (list_empty(&anchor
->urb_list
))
159 wake_up(&anchor
->wait
);
161 EXPORT_SYMBOL_GPL(usb_unanchor_urb
);
163 /*-------------------------------------------------------------------*/
166 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
167 * @urb: pointer to the urb describing the request
168 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
169 * of valid options for this.
171 * This submits a transfer request, and transfers control of the URB
172 * describing that request to the USB subsystem. Request completion will
173 * be indicated later, asynchronously, by calling the completion handler.
174 * The three types of completion are success, error, and unlink
175 * (a software-induced fault, also called "request cancellation").
177 * URBs may be submitted in interrupt context.
179 * The caller must have correctly initialized the URB before submitting
180 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
181 * available to ensure that most fields are correctly initialized, for
182 * the particular kind of transfer, although they will not initialize
183 * any transfer flags.
185 * Successful submissions return 0; otherwise this routine returns a
186 * negative error number. If the submission is successful, the complete()
187 * callback from the URB will be called exactly once, when the USB core and
188 * Host Controller Driver (HCD) are finished with the URB. When the completion
189 * function is called, control of the URB is returned to the device
190 * driver which issued the request. The completion handler may then
191 * immediately free or reuse that URB.
193 * With few exceptions, USB device drivers should never access URB fields
194 * provided by usbcore or the HCD until its complete() is called.
195 * The exceptions relate to periodic transfer scheduling. For both
196 * interrupt and isochronous urbs, as part of successful URB submission
197 * urb->interval is modified to reflect the actual transfer period used
198 * (normally some power of two units). And for isochronous urbs,
199 * urb->start_frame is modified to reflect when the URB's transfers were
200 * scheduled to start. Not all isochronous transfer scheduling policies
201 * will work, but most host controller drivers should easily handle ISO
202 * queues going from now until 10-200 msec into the future.
204 * For control endpoints, the synchronous usb_control_msg() call is
205 * often used (in non-interrupt context) instead of this call.
206 * That is often used through convenience wrappers, for the requests
207 * that are standardized in the USB 2.0 specification. For bulk
208 * endpoints, a synchronous usb_bulk_msg() call is available.
212 * URBs may be submitted to endpoints before previous ones complete, to
213 * minimize the impact of interrupt latencies and system overhead on data
214 * throughput. With that queuing policy, an endpoint's queue would never
215 * be empty. This is required for continuous isochronous data streams,
216 * and may also be required for some kinds of interrupt transfers. Such
217 * queuing also maximizes bandwidth utilization by letting USB controllers
218 * start work on later requests before driver software has finished the
219 * completion processing for earlier (successful) requests.
221 * As of Linux 2.6, all USB endpoint transfer queues support depths greater
222 * than one. This was previously a HCD-specific behavior, except for ISO
223 * transfers. Non-isochronous endpoint queues are inactive during cleanup
224 * after faults (transfer errors or cancellation).
226 * Reserved Bandwidth Transfers:
228 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
229 * using the interval specified in the urb. Submitting the first urb to
230 * the endpoint reserves the bandwidth necessary to make those transfers.
231 * If the USB subsystem can't allocate sufficient bandwidth to perform
232 * the periodic request, submitting such a periodic request should fail.
234 * Device drivers must explicitly request that repetition, by ensuring that
235 * some URB is always on the endpoint's queue (except possibly for short
236 * periods during completion callacks). When there is no longer an urb
237 * queued, the endpoint's bandwidth reservation is canceled. This means
238 * drivers can use their completion handlers to ensure they keep bandwidth
239 * they need, by reinitializing and resubmitting the just-completed urb
240 * until the driver longer needs that periodic bandwidth.
244 * The general rules for how to decide which mem_flags to use
245 * are the same as for kmalloc. There are four
246 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
249 * GFP_NOFS is not ever used, as it has not been implemented yet.
251 * GFP_ATOMIC is used when
252 * (a) you are inside a completion handler, an interrupt, bottom half,
253 * tasklet or timer, or
254 * (b) you are holding a spinlock or rwlock (does not apply to
256 * (c) current->state != TASK_RUNNING, this is the case only after
259 * GFP_NOIO is used in the block io path and error handling of storage
262 * All other situations use GFP_KERNEL.
264 * Some more specific rules for mem_flags can be inferred, such as
265 * (1) start_xmit, timeout, and receive methods of network drivers must
266 * use GFP_ATOMIC (they are called with a spinlock held);
267 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
268 * called with a spinlock held);
269 * (3) If you use a kernel thread with a network driver you must use
270 * GFP_NOIO, unless (b) or (c) apply;
271 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
272 * apply or your are in a storage driver's block io path;
273 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
274 * (6) changing firmware on a running storage or net device uses
275 * GFP_NOIO, unless b) or c) apply
278 int usb_submit_urb(struct urb
*urb
, gfp_t mem_flags
)
281 struct usb_device
*dev
;
282 struct usb_host_endpoint
*ep
;
285 if (!urb
|| urb
->hcpriv
|| !urb
->complete
)
287 if (!(dev
= urb
->dev
) ||
288 (dev
->state
< USB_STATE_DEFAULT
) ||
289 (!dev
->bus
) || (dev
->devnum
<= 0))
291 if (dev
->bus
->controller
->power
.power_state
.event
!= PM_EVENT_ON
292 || dev
->state
== USB_STATE_SUSPENDED
)
293 return -EHOSTUNREACH
;
295 /* For now, get the endpoint from the pipe. Eventually drivers
296 * will be required to set urb->ep directly and we will eliminate
299 ep
= (usb_pipein(urb
->pipe
) ? dev
->ep_in
: dev
->ep_out
)
300 [usb_pipeendpoint(urb
->pipe
)];
305 urb
->status
= -EINPROGRESS
;
306 urb
->actual_length
= 0;
308 /* Lots of sanity checks, so HCDs can rely on clean data
309 * and don't need to duplicate tests
311 xfertype
= usb_endpoint_type(&ep
->desc
);
312 is_out
= usb_pipeout(urb
->pipe
);
314 if (xfertype
!= USB_ENDPOINT_XFER_CONTROL
&&
315 dev
->state
< USB_STATE_CONFIGURED
)
318 max
= le16_to_cpu(ep
->desc
.wMaxPacketSize
);
321 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
322 usb_endpoint_num(&ep
->desc
), is_out
? "out" : "in",
327 /* periodic transfers limit size per frame/uframe,
328 * but drivers only control those sizes for ISO.
329 * while we're checking, initialize return status.
331 if (xfertype
== USB_ENDPOINT_XFER_ISOC
) {
334 /* "high bandwidth" mode, 1-3 packets/uframe? */
335 if (dev
->speed
== USB_SPEED_HIGH
) {
336 int mult
= 1 + ((max
>> 11) & 0x03);
341 if (urb
->number_of_packets
<= 0)
343 for (n
= 0; n
< urb
->number_of_packets
; n
++) {
344 len
= urb
->iso_frame_desc
[n
].length
;
345 if (len
< 0 || len
> max
)
347 urb
->iso_frame_desc
[n
].status
= -EXDEV
;
348 urb
->iso_frame_desc
[n
].actual_length
= 0;
352 /* the I/O buffer must be mapped/unmapped, except when length=0 */
353 if (urb
->transfer_buffer_length
< 0)
357 /* stuff that drivers shouldn't do, but which shouldn't
358 * cause problems in HCDs if they get it wrong.
361 unsigned int orig_flags
= urb
->transfer_flags
;
362 unsigned int allowed
;
364 /* enforce simple/standard policy */
365 allowed
= (URB_NO_TRANSFER_DMA_MAP
| URB_NO_SETUP_DMA_MAP
|
368 case USB_ENDPOINT_XFER_BULK
:
370 allowed
|= URB_ZERO_PACKET
;
372 case USB_ENDPOINT_XFER_CONTROL
:
373 allowed
|= URB_NO_FSBR
; /* only affects UHCI */
375 default: /* all non-iso endpoints */
377 allowed
|= URB_SHORT_NOT_OK
;
379 case USB_ENDPOINT_XFER_ISOC
:
380 allowed
|= URB_ISO_ASAP
;
383 urb
->transfer_flags
&= allowed
;
385 /* fail if submitter gave bogus flags */
386 if (urb
->transfer_flags
!= orig_flags
) {
387 err("BOGUS urb flags, %x --> %x",
388 orig_flags
, urb
->transfer_flags
);
394 * Force periodic transfer intervals to be legal values that are
395 * a power of two (so HCDs don't need to).
397 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
398 * supports different values... this uses EHCI/UHCI defaults (and
399 * EHCI can use smaller non-default values).
402 case USB_ENDPOINT_XFER_ISOC
:
403 case USB_ENDPOINT_XFER_INT
:
405 if (urb
->interval
<= 0)
408 switch (dev
->speed
) {
409 case USB_SPEED_HIGH
: /* units are microframes */
410 // NOTE usb handles 2^15
411 if (urb
->interval
> (1024 * 8))
412 urb
->interval
= 1024 * 8;
415 case USB_SPEED_FULL
: /* units are frames/msec */
417 if (xfertype
== USB_ENDPOINT_XFER_INT
) {
418 if (urb
->interval
> 255)
420 // NOTE ohci only handles up to 32
423 if (urb
->interval
> 1024)
424 urb
->interval
= 1024;
425 // NOTE usb and ohci handle up to 2^15
433 while (max
> urb
->interval
)
438 return usb_hcd_submit_urb(urb
, mem_flags
);
441 /*-------------------------------------------------------------------*/
444 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
445 * @urb: pointer to urb describing a previously submitted request,
448 * This routine cancels an in-progress request. URBs complete only once
449 * per submission, and may be canceled only once per submission.
450 * Successful cancellation means termination of @urb will be expedited
451 * and the completion handler will be called with a status code
452 * indicating that the request has been canceled (rather than any other
455 * This request is always asynchronous. Success is indicated by
456 * returning -EINPROGRESS, at which time the URB will probably not yet
457 * have been given back to the device driver. When it is eventually
458 * called, the completion function will see @urb->status == -ECONNRESET.
459 * Failure is indicated by usb_unlink_urb() returning any other value.
460 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
461 * never submitted, or it was unlinked before, or the hardware is already
462 * finished with it), even if the completion handler has not yet run.
464 * Unlinking and Endpoint Queues:
466 * [The behaviors and guarantees described below do not apply to virtual
467 * root hubs but only to endpoint queues for physical USB devices.]
469 * Host Controller Drivers (HCDs) place all the URBs for a particular
470 * endpoint in a queue. Normally the queue advances as the controller
471 * hardware processes each request. But when an URB terminates with an
472 * error its queue generally stops (see below), at least until that URB's
473 * completion routine returns. It is guaranteed that a stopped queue
474 * will not restart until all its unlinked URBs have been fully retired,
475 * with their completion routines run, even if that's not until some time
476 * after the original completion handler returns. The same behavior and
477 * guarantee apply when an URB terminates because it was unlinked.
479 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
480 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
481 * and -EREMOTEIO. Control endpoint queues behave the same way except
482 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
483 * for isochronous endpoints are treated differently, because they must
484 * advance at fixed rates. Such queues do not stop when an URB
485 * encounters an error or is unlinked. An unlinked isochronous URB may
486 * leave a gap in the stream of packets; it is undefined whether such
487 * gaps can be filled in.
489 * Note that early termination of an URB because a short packet was
490 * received will generate a -EREMOTEIO error if and only if the
491 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
492 * drivers can build deep queues for large or complex bulk transfers
493 * and clean them up reliably after any sort of aborted transfer by
494 * unlinking all pending URBs at the first fault.
496 * When a control URB terminates with an error other than -EREMOTEIO, it
497 * is quite likely that the status stage of the transfer will not take
500 int usb_unlink_urb(struct urb
*urb
)
504 if (!(urb
->dev
&& urb
->dev
->bus
))
506 return usb_hcd_unlink_urb(urb
, -ECONNRESET
);
510 * usb_kill_urb - cancel a transfer request and wait for it to finish
511 * @urb: pointer to URB describing a previously submitted request,
514 * This routine cancels an in-progress request. It is guaranteed that
515 * upon return all completion handlers will have finished and the URB
516 * will be totally idle and available for reuse. These features make
517 * this an ideal way to stop I/O in a disconnect() callback or close()
518 * function. If the request has not already finished or been unlinked
519 * the completion handler will see urb->status == -ENOENT.
521 * While the routine is running, attempts to resubmit the URB will fail
522 * with error -EPERM. Thus even if the URB's completion handler always
523 * tries to resubmit, it will not succeed and the URB will become idle.
525 * This routine may not be used in an interrupt context (such as a bottom
526 * half or a completion handler), or when holding a spinlock, or in other
527 * situations where the caller can't schedule().
529 void usb_kill_urb(struct urb
*urb
)
532 if (!(urb
&& urb
->dev
&& urb
->dev
->bus
))
534 spin_lock_irq(&urb
->lock
);
536 spin_unlock_irq(&urb
->lock
);
538 usb_hcd_unlink_urb(urb
, -ENOENT
);
539 wait_event(usb_kill_urb_queue
, atomic_read(&urb
->use_count
) == 0);
541 spin_lock_irq(&urb
->lock
);
543 spin_unlock_irq(&urb
->lock
);
547 * usb_kill_anchored_urbs - cancel transfer requests en masse
548 * @anchor: anchor the requests are bound to
550 * this allows all outstanding URBs to be killed starting
551 * from the back of the queue
553 void usb_kill_anchored_urbs(struct usb_anchor
*anchor
)
557 spin_lock_irq(&anchor
->lock
);
558 while (!list_empty(&anchor
->urb_list
)) {
559 victim
= list_entry(anchor
->urb_list
.prev
, struct urb
, anchor_list
);
560 /* we must make sure the URB isn't freed before we kill it*/
562 spin_unlock_irq(&anchor
->lock
);
563 /* this will unanchor the URB */
564 usb_kill_urb(victim
);
566 spin_lock_irq(&anchor
->lock
);
568 spin_unlock_irq(&anchor
->lock
);
570 EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs
);
573 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
574 * @anchor: the anchor you want to become unused
575 * @timeout: how long you are willing to wait in milliseconds
577 * Call this is you want to be sure all an anchor's
580 int usb_wait_anchor_empty_timeout(struct usb_anchor
*anchor
,
581 unsigned int timeout
)
583 return wait_event_timeout(anchor
->wait
, list_empty(&anchor
->urb_list
),
584 msecs_to_jiffies(timeout
));
586 EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout
);
588 EXPORT_SYMBOL(usb_init_urb
);
589 EXPORT_SYMBOL(usb_alloc_urb
);
590 EXPORT_SYMBOL(usb_free_urb
);
591 EXPORT_SYMBOL(usb_get_urb
);
592 EXPORT_SYMBOL(usb_submit_urb
);
593 EXPORT_SYMBOL(usb_unlink_urb
);
594 EXPORT_SYMBOL(usb_kill_urb
);