blob: 9d7e63292c01175647503b65e821cdd3b94dc381 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001#include <linux/module.h>
2#include <linux/string.h>
3#include <linux/bitops.h>
4#include <linux/slab.h>
5#include <linux/init.h>
Alan Sternd617bc82007-08-02 15:04:52 -04006#include <linux/log2.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007#include <linux/usb.h>
Oliver Neukum51a2f072007-05-25 13:40:56 +02008#include <linux/wait.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07009#include "hcd.h"
10
11#define to_urb(d) container_of(d, struct urb, kref)
12
13static void urb_destroy(struct kref *kref)
14{
15 struct urb *urb = to_urb(kref);
Oliver Neukum51a2f072007-05-25 13:40:56 +020016
Marcel Holtmann8b3b01c2007-06-13 08:02:11 +020017 if (urb->transfer_flags & URB_FREE_BUFFER)
18 kfree(urb->transfer_buffer);
19
Linus Torvalds1da177e2005-04-16 15:20:36 -070020 kfree(urb);
21}
22
23/**
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
26 *
27 * Initializes a urb so that the USB subsystem can use it properly.
28 *
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.
34 *
35 * Only use this function if you _really_ understand what you are doing.
36 */
37void usb_init_urb(struct urb *urb)
38{
39 if (urb) {
40 memset(urb, 0, sizeof(*urb));
41 kref_init(&urb->kref);
Oliver Neukum51a2f072007-05-25 13:40:56 +020042 INIT_LIST_HEAD(&urb->anchor_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 }
44}
Greg Kroah-Hartman782e70c2008-01-25 11:12:21 -060045EXPORT_SYMBOL_GPL(usb_init_urb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
47/**
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.
52 *
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.
55 *
56 * If no memory is available, NULL is returned.
57 *
58 * If the driver want to use this urb for interrupt, control, or bulk
59 * endpoints, pass '0' as the number of iso packets.
60 *
61 * The driver must call usb_free_urb() when it is finished with the urb.
62 */
Al Viro55016f12005-10-21 03:21:58 -040063struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -070064{
65 struct urb *urb;
66
Tobias Klauserec17cf12006-09-13 21:38:41 +020067 urb = kmalloc(sizeof(struct urb) +
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 iso_packets * sizeof(struct usb_iso_packet_descriptor),
69 mem_flags);
70 if (!urb) {
71 err("alloc_urb: kmalloc failed");
72 return NULL;
73 }
74 usb_init_urb(urb);
75 return urb;
76}
Greg Kroah-Hartman782e70c2008-01-25 11:12:21 -060077EXPORT_SYMBOL_GPL(usb_alloc_urb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
79/**
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
82 *
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.
85 *
86 * Note: The transfer buffer associated with the urb is not freed, that must be
87 * done elsewhere.
88 */
89void usb_free_urb(struct urb *urb)
90{
91 if (urb)
92 kref_put(&urb->kref, urb_destroy);
93}
Greg Kroah-Hartman782e70c2008-01-25 11:12:21 -060094EXPORT_SYMBOL_GPL(usb_free_urb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
96/**
97 * usb_get_urb - increments the reference count of the urb
98 * @urb: pointer to the urb to modify, may be NULL
99 *
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
102 * for urbs.
103 *
104 * A pointer to the urb with the incremented reference counter is returned.
105 */
Greg Kroah-Hartman2c044a42008-01-30 15:21:33 -0800106struct urb *usb_get_urb(struct urb *urb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107{
108 if (urb)
109 kref_get(&urb->kref);
110 return urb;
111}
Greg Kroah-Hartman782e70c2008-01-25 11:12:21 -0600112EXPORT_SYMBOL_GPL(usb_get_urb);
Oliver Neukum51a2f072007-05-25 13:40:56 +0200113
114/**
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
118 *
119 * This can be called to have access to URBs which are to be executed
120 * without bothering to track them
121 */
122void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor)
123{
124 unsigned long flags;
125
126 spin_lock_irqsave(&anchor->lock, flags);
127 usb_get_urb(urb);
128 list_add_tail(&urb->anchor_list, &anchor->urb_list);
129 urb->anchor = anchor;
130 spin_unlock_irqrestore(&anchor->lock, flags);
131}
132EXPORT_SYMBOL_GPL(usb_anchor_urb);
133
134/**
135 * usb_unanchor_urb - unanchors an URB
136 * @urb: pointer to the urb to anchor
137 *
138 * Call this to stop the system keeping track of this URB
139 */
140void usb_unanchor_urb(struct urb *urb)
141{
142 unsigned long flags;
143 struct usb_anchor *anchor;
144
145 if (!urb)
146 return;
147
148 anchor = urb->anchor;
149 if (!anchor)
150 return;
151
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);
156 return;
157 }
158 urb->anchor = NULL;
159 list_del(&urb->anchor_list);
160 spin_unlock_irqrestore(&anchor->lock, flags);
161 usb_put_urb(urb);
162 if (list_empty(&anchor->urb_list))
163 wake_up(&anchor->wait);
164}
165EXPORT_SYMBOL_GPL(usb_unanchor_urb);
166
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167/*-------------------------------------------------------------------*/
168
169/**
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.
174 *
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
Greg Kroah-Hartman2c044a42008-01-30 15:21:33 -0800179 * (a software-induced fault, also called "request cancellation").
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 *
181 * URBs may be submitted in interrupt context.
182 *
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.
188 *
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.
196 *
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.
207 *
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.
213 *
214 * Request Queuing:
215 *
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.
224 *
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
Steven Cole093cf722005-05-03 19:07:24 -0600228 * after faults (transfer errors or cancellation).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 *
230 * Reserved Bandwidth Transfers:
231 *
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.
237 *
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.
245 *
246 * Memory Flags:
247 *
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
251 * GFP_ATOMIC.
252 *
253 * GFP_NOFS is not ever used, as it has not been implemented yet.
254 *
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
259 * semaphores), or
260 * (c) current->state != TASK_RUNNING, this is the case only after
261 * you've changed it.
Greg Kroah-Hartman2c044a42008-01-30 15:21:33 -0800262 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 * GFP_NOIO is used in the block io path and error handling of storage
264 * devices.
265 *
266 * All other situations use GFP_KERNEL.
267 *
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
280 *
281 */
Al Viro55016f12005-10-21 03:21:58 -0400282int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283{
Alan Stern5b653c72007-07-30 17:04:37 -0400284 int xfertype, max;
285 struct usb_device *dev;
286 struct usb_host_endpoint *ep;
287 int is_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288
289 if (!urb || urb->hcpriv || !urb->complete)
290 return -EINVAL;
Greg Kroah-Hartman2c044a42008-01-30 15:21:33 -0800291 dev = urb->dev;
292 if ((!dev) || (dev->state < USB_STATE_DEFAULT))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294
Alan Stern5b653c72007-07-30 17:04:37 -0400295 /* For now, get the endpoint from the pipe. Eventually drivers
296 * will be required to set urb->ep directly and we will eliminate
297 * urb->pipe.
298 */
299 ep = (usb_pipein(urb->pipe) ? dev->ep_in : dev->ep_out)
300 [usb_pipeendpoint(urb->pipe)];
301 if (!ep)
302 return -ENOENT;
303
304 urb->ep = ep;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 urb->status = -EINPROGRESS;
306 urb->actual_length = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307
308 /* Lots of sanity checks, so HCDs can rely on clean data
309 * and don't need to duplicate tests
310 */
Alan Stern5b653c72007-07-30 17:04:37 -0400311 xfertype = usb_endpoint_type(&ep->desc);
Alan Sternfea34092007-07-30 17:06:16 -0400312 if (xfertype == USB_ENDPOINT_XFER_CONTROL) {
313 struct usb_ctrlrequest *setup =
314 (struct usb_ctrlrequest *) urb->setup_packet;
315
316 if (!setup)
317 return -ENOEXEC;
318 is_out = !(setup->bRequestType & USB_DIR_IN) ||
319 !setup->wLength;
320 } else {
321 is_out = usb_endpoint_dir_out(&ep->desc);
322 }
323
324 /* Cache the direction for later use */
325 urb->transfer_flags = (urb->transfer_flags & ~URB_DIR_MASK) |
326 (is_out ? URB_DIR_OUT : URB_DIR_IN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327
Alan Stern5b653c72007-07-30 17:04:37 -0400328 if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
329 dev->state < USB_STATE_CONFIGURED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 return -ENODEV;
331
Alan Stern5b653c72007-07-30 17:04:37 -0400332 max = le16_to_cpu(ep->desc.wMaxPacketSize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 if (max <= 0) {
334 dev_dbg(&dev->dev,
335 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
Alan Stern5b653c72007-07-30 17:04:37 -0400336 usb_endpoint_num(&ep->desc), is_out ? "out" : "in",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 __FUNCTION__, max);
338 return -EMSGSIZE;
339 }
340
341 /* periodic transfers limit size per frame/uframe,
342 * but drivers only control those sizes for ISO.
343 * while we're checking, initialize return status.
344 */
Alan Stern5b653c72007-07-30 17:04:37 -0400345 if (xfertype == USB_ENDPOINT_XFER_ISOC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 int n, len;
347
348 /* "high bandwidth" mode, 1-3 packets/uframe? */
349 if (dev->speed == USB_SPEED_HIGH) {
350 int mult = 1 + ((max >> 11) & 0x03);
351 max &= 0x07ff;
352 max *= mult;
353 }
354
Greg Kroah-Hartman2c044a42008-01-30 15:21:33 -0800355 if (urb->number_of_packets <= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 return -EINVAL;
357 for (n = 0; n < urb->number_of_packets; n++) {
Oliver Neukum92516442007-01-23 15:55:28 -0500358 len = urb->iso_frame_desc[n].length;
Greg Kroah-Hartman2c044a42008-01-30 15:21:33 -0800359 if (len < 0 || len > max)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 return -EMSGSIZE;
Oliver Neukum92516442007-01-23 15:55:28 -0500361 urb->iso_frame_desc[n].status = -EXDEV;
362 urb->iso_frame_desc[n].actual_length = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 }
364 }
365
366 /* the I/O buffer must be mapped/unmapped, except when length=0 */
367 if (urb->transfer_buffer_length < 0)
368 return -EMSGSIZE;
369
370#ifdef DEBUG
371 /* stuff that drivers shouldn't do, but which shouldn't
372 * cause problems in HCDs if they get it wrong.
373 */
374 {
375 unsigned int orig_flags = urb->transfer_flags;
376 unsigned int allowed;
377
378 /* enforce simple/standard policy */
Alan Sternb375a042005-07-29 16:11:07 -0400379 allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_SETUP_DMA_MAP |
Oliver Neukum0b28baa2007-10-17 14:37:54 +0200380 URB_NO_INTERRUPT | URB_DIR_MASK | URB_FREE_BUFFER);
Alan Stern5b653c72007-07-30 17:04:37 -0400381 switch (xfertype) {
382 case USB_ENDPOINT_XFER_BULK:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 if (is_out)
384 allowed |= URB_ZERO_PACKET;
385 /* FALLTHROUGH */
Alan Stern5b653c72007-07-30 17:04:37 -0400386 case USB_ENDPOINT_XFER_CONTROL:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 allowed |= URB_NO_FSBR; /* only affects UHCI */
388 /* FALLTHROUGH */
389 default: /* all non-iso endpoints */
390 if (!is_out)
391 allowed |= URB_SHORT_NOT_OK;
392 break;
Alan Stern5b653c72007-07-30 17:04:37 -0400393 case USB_ENDPOINT_XFER_ISOC:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 allowed |= URB_ISO_ASAP;
395 break;
396 }
397 urb->transfer_flags &= allowed;
398
399 /* fail if submitter gave bogus flags */
400 if (urb->transfer_flags != orig_flags) {
Oliver Neukum92516442007-01-23 15:55:28 -0500401 err("BOGUS urb flags, %x --> %x",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 orig_flags, urb->transfer_flags);
403 return -EINVAL;
404 }
405 }
406#endif
407 /*
408 * Force periodic transfer intervals to be legal values that are
409 * a power of two (so HCDs don't need to).
410 *
411 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
412 * supports different values... this uses EHCI/UHCI defaults (and
413 * EHCI can use smaller non-default values).
414 */
Alan Stern5b653c72007-07-30 17:04:37 -0400415 switch (xfertype) {
416 case USB_ENDPOINT_XFER_ISOC:
417 case USB_ENDPOINT_XFER_INT:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 /* too small? */
419 if (urb->interval <= 0)
420 return -EINVAL;
421 /* too big? */
422 switch (dev->speed) {
423 case USB_SPEED_HIGH: /* units are microframes */
Greg Kroah-Hartman2c044a42008-01-30 15:21:33 -0800424 /* NOTE usb handles 2^15 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 if (urb->interval > (1024 * 8))
426 urb->interval = 1024 * 8;
Alan Stern5b653c72007-07-30 17:04:37 -0400427 max = 1024 * 8;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 break;
429 case USB_SPEED_FULL: /* units are frames/msec */
430 case USB_SPEED_LOW:
Alan Stern5b653c72007-07-30 17:04:37 -0400431 if (xfertype == USB_ENDPOINT_XFER_INT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 if (urb->interval > 255)
433 return -EINVAL;
Greg Kroah-Hartman2c044a42008-01-30 15:21:33 -0800434 /* NOTE ohci only handles up to 32 */
Alan Stern5b653c72007-07-30 17:04:37 -0400435 max = 128;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 } else {
437 if (urb->interval > 1024)
438 urb->interval = 1024;
Greg Kroah-Hartman2c044a42008-01-30 15:21:33 -0800439 /* NOTE usb and ohci handle up to 2^15 */
Alan Stern5b653c72007-07-30 17:04:37 -0400440 max = 1024;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 }
442 break;
443 default:
444 return -EINVAL;
445 }
Alan Sternd617bc82007-08-02 15:04:52 -0400446 /* Round down to a power of 2, no more than max */
447 urb->interval = min(max, 1 << ilog2(urb->interval));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 }
449
Oliver Neukum92516442007-01-23 15:55:28 -0500450 return usb_hcd_submit_urb(urb, mem_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451}
Greg Kroah-Hartman782e70c2008-01-25 11:12:21 -0600452EXPORT_SYMBOL_GPL(usb_submit_urb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453
454/*-------------------------------------------------------------------*/
455
456/**
457 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
458 * @urb: pointer to urb describing a previously submitted request,
459 * may be NULL
460 *
Alan Sternbeafef02007-07-13 15:47:16 -0400461 * This routine cancels an in-progress request. URBs complete only once
462 * per submission, and may be canceled only once per submission.
463 * Successful cancellation means termination of @urb will be expedited
464 * and the completion handler will be called with a status code
465 * indicating that the request has been canceled (rather than any other
466 * code).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 *
Alan Sternbeafef02007-07-13 15:47:16 -0400468 * This request is always asynchronous. Success is indicated by
469 * returning -EINPROGRESS, at which time the URB will probably not yet
470 * have been given back to the device driver. When it is eventually
471 * called, the completion function will see @urb->status == -ECONNRESET.
472 * Failure is indicated by usb_unlink_urb() returning any other value.
473 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
474 * never submitted, or it was unlinked before, or the hardware is already
475 * finished with it), even if the completion handler has not yet run.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 *
477 * Unlinking and Endpoint Queues:
478 *
Alan Sternbeafef02007-07-13 15:47:16 -0400479 * [The behaviors and guarantees described below do not apply to virtual
480 * root hubs but only to endpoint queues for physical USB devices.]
481 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482 * Host Controller Drivers (HCDs) place all the URBs for a particular
483 * endpoint in a queue. Normally the queue advances as the controller
Alan Stern8835f662005-04-18 17:39:30 -0700484 * hardware processes each request. But when an URB terminates with an
Alan Sternbeafef02007-07-13 15:47:16 -0400485 * error its queue generally stops (see below), at least until that URB's
486 * completion routine returns. It is guaranteed that a stopped queue
487 * will not restart until all its unlinked URBs have been fully retired,
488 * with their completion routines run, even if that's not until some time
489 * after the original completion handler returns. The same behavior and
490 * guarantee apply when an URB terminates because it was unlinked.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 *
Alan Sternbeafef02007-07-13 15:47:16 -0400492 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
493 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
494 * and -EREMOTEIO. Control endpoint queues behave the same way except
495 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
496 * for isochronous endpoints are treated differently, because they must
497 * advance at fixed rates. Such queues do not stop when an URB
498 * encounters an error or is unlinked. An unlinked isochronous URB may
499 * leave a gap in the stream of packets; it is undefined whether such
500 * gaps can be filled in.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 *
Alan Sternbeafef02007-07-13 15:47:16 -0400502 * Note that early termination of an URB because a short packet was
503 * received will generate a -EREMOTEIO error if and only if the
504 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
505 * drivers can build deep queues for large or complex bulk transfers
506 * and clean them up reliably after any sort of aborted transfer by
507 * unlinking all pending URBs at the first fault.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 *
Alan Sternbeafef02007-07-13 15:47:16 -0400509 * When a control URB terminates with an error other than -EREMOTEIO, it
510 * is quite likely that the status stage of the transfer will not take
511 * place.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 */
513int usb_unlink_urb(struct urb *urb)
514{
515 if (!urb)
516 return -EINVAL;
Alan Sternd617bc82007-08-02 15:04:52 -0400517 if (!urb->dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 return -ENODEV;
Alan Sternd617bc82007-08-02 15:04:52 -0400519 if (!urb->ep)
520 return -EIDRM;
Alan Sterna6d2bb92006-08-30 11:27:36 -0400521 return usb_hcd_unlink_urb(urb, -ECONNRESET);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522}
Greg Kroah-Hartman782e70c2008-01-25 11:12:21 -0600523EXPORT_SYMBOL_GPL(usb_unlink_urb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524
525/**
526 * usb_kill_urb - cancel a transfer request and wait for it to finish
527 * @urb: pointer to URB describing a previously submitted request,
528 * may be NULL
529 *
530 * This routine cancels an in-progress request. It is guaranteed that
531 * upon return all completion handlers will have finished and the URB
532 * will be totally idle and available for reuse. These features make
533 * this an ideal way to stop I/O in a disconnect() callback or close()
534 * function. If the request has not already finished or been unlinked
535 * the completion handler will see urb->status == -ENOENT.
536 *
537 * While the routine is running, attempts to resubmit the URB will fail
538 * with error -EPERM. Thus even if the URB's completion handler always
539 * tries to resubmit, it will not succeed and the URB will become idle.
540 *
541 * This routine may not be used in an interrupt context (such as a bottom
542 * half or a completion handler), or when holding a spinlock, or in other
543 * situations where the caller can't schedule().
544 */
545void usb_kill_urb(struct urb *urb)
546{
Alan Stern1431d2a2007-08-24 15:42:39 -0400547 static DEFINE_MUTEX(reject_mutex);
548
Greg Kroah-Hartmane9aa7952006-01-23 17:17:21 -0500549 might_sleep();
Alan Sternd617bc82007-08-02 15:04:52 -0400550 if (!(urb && urb->dev && urb->ep))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 return;
Alan Stern1431d2a2007-08-24 15:42:39 -0400552 mutex_lock(&reject_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 ++urb->reject;
Alan Stern1431d2a2007-08-24 15:42:39 -0400554 mutex_unlock(&reject_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555
Alan Sterna6d2bb92006-08-30 11:27:36 -0400556 usb_hcd_unlink_urb(urb, -ENOENT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
558
Alan Stern1431d2a2007-08-24 15:42:39 -0400559 mutex_lock(&reject_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 --urb->reject;
Alan Stern1431d2a2007-08-24 15:42:39 -0400561 mutex_unlock(&reject_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562}
Greg Kroah-Hartman782e70c2008-01-25 11:12:21 -0600563EXPORT_SYMBOL_GPL(usb_kill_urb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564
Oliver Neukum51a2f072007-05-25 13:40:56 +0200565/**
566 * usb_kill_anchored_urbs - cancel transfer requests en masse
567 * @anchor: anchor the requests are bound to
568 *
569 * this allows all outstanding URBs to be killed starting
570 * from the back of the queue
571 */
572void usb_kill_anchored_urbs(struct usb_anchor *anchor)
573{
574 struct urb *victim;
575
576 spin_lock_irq(&anchor->lock);
577 while (!list_empty(&anchor->urb_list)) {
Greg Kroah-Hartman2c044a42008-01-30 15:21:33 -0800578 victim = list_entry(anchor->urb_list.prev, struct urb,
579 anchor_list);
Oliver Neukum51a2f072007-05-25 13:40:56 +0200580 /* we must make sure the URB isn't freed before we kill it*/
581 usb_get_urb(victim);
582 spin_unlock_irq(&anchor->lock);
583 /* this will unanchor the URB */
584 usb_kill_urb(victim);
585 usb_put_urb(victim);
586 spin_lock_irq(&anchor->lock);
587 }
588 spin_unlock_irq(&anchor->lock);
589}
590EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs);
591
592/**
593 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
594 * @anchor: the anchor you want to become unused
595 * @timeout: how long you are willing to wait in milliseconds
596 *
597 * Call this is you want to be sure all an anchor's
598 * URBs have finished
599 */
600int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
601 unsigned int timeout)
602{
603 return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list),
604 msecs_to_jiffies(timeout));
605}
606EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout);