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1da177e4 LT |
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> | |
d617bc83 | 6 | #include <linux/log2.h> |
1da177e4 | 7 | #include <linux/usb.h> |
51a2f077 | 8 | #include <linux/wait.h> |
1da177e4 LT |
9 | #include "hcd.h" |
10 | ||
11 | #define to_urb(d) container_of(d, struct urb, kref) | |
12 | ||
13 | static void urb_destroy(struct kref *kref) | |
14 | { | |
15 | struct urb *urb = to_urb(kref); | |
51a2f077 | 16 | |
8b3b01c8 MH |
17 | if (urb->transfer_flags & URB_FREE_BUFFER) |
18 | kfree(urb->transfer_buffer); | |
19 | ||
1da177e4 LT |
20 | 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 | */ | |
37 | void usb_init_urb(struct urb *urb) | |
38 | { | |
39 | if (urb) { | |
40 | memset(urb, 0, sizeof(*urb)); | |
41 | kref_init(&urb->kref); | |
51a2f077 | 42 | INIT_LIST_HEAD(&urb->anchor_list); |
1da177e4 LT |
43 | } |
44 | } | |
782e70c6 | 45 | EXPORT_SYMBOL_GPL(usb_init_urb); |
1da177e4 LT |
46 | |
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 | */ | |
55016f10 | 63 | struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags) |
1da177e4 LT |
64 | { |
65 | struct urb *urb; | |
66 | ||
ec17cf1c | 67 | urb = kmalloc(sizeof(struct urb) + |
1da177e4 LT |
68 | 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 | } | |
782e70c6 | 77 | EXPORT_SYMBOL_GPL(usb_alloc_urb); |
1da177e4 LT |
78 | |
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 | */ | |
89 | void usb_free_urb(struct urb *urb) | |
90 | { | |
91 | if (urb) | |
92 | kref_put(&urb->kref, urb_destroy); | |
93 | } | |
782e70c6 | 94 | EXPORT_SYMBOL_GPL(usb_free_urb); |
1da177e4 LT |
95 | |
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 | */ | |
106 | struct urb * usb_get_urb(struct urb *urb) | |
107 | { | |
108 | if (urb) | |
109 | kref_get(&urb->kref); | |
110 | return urb; | |
111 | } | |
782e70c6 | 112 | EXPORT_SYMBOL_GPL(usb_get_urb); |
51a2f077 ON |
113 | |
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 | */ | |
122 | void 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 | } | |
132 | EXPORT_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 | */ | |
140 | void 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 | } | |
165 | EXPORT_SYMBOL_GPL(usb_unanchor_urb); | |
166 | ||
1da177e4 LT |
167 | /*-------------------------------------------------------------------*/ |
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 | |
093cf723 | 179 | * (a software-induced fault, also called "request cancellation"). |
1da177e4 LT |
180 | * |
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 | |
093cf723 | 228 | * after faults (transfer errors or cancellation). |
1da177e4 LT |
229 | * |
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. | |
262 | * | |
263 | * 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 | */ | |
55016f10 | 282 | int usb_submit_urb(struct urb *urb, gfp_t mem_flags) |
1da177e4 | 283 | { |
5b653c79 AS |
284 | int xfertype, max; |
285 | struct usb_device *dev; | |
286 | struct usb_host_endpoint *ep; | |
287 | int is_out; | |
1da177e4 LT |
288 | |
289 | if (!urb || urb->hcpriv || !urb->complete) | |
290 | return -EINVAL; | |
4326ed0b | 291 | if (!(dev = urb->dev) || dev->state < USB_STATE_DEFAULT) |
1da177e4 | 292 | return -ENODEV; |
1da177e4 | 293 | |
5b653c79 AS |
294 | /* For now, get the endpoint from the pipe. Eventually drivers |
295 | * will be required to set urb->ep directly and we will eliminate | |
296 | * urb->pipe. | |
297 | */ | |
298 | ep = (usb_pipein(urb->pipe) ? dev->ep_in : dev->ep_out) | |
299 | [usb_pipeendpoint(urb->pipe)]; | |
300 | if (!ep) | |
301 | return -ENOENT; | |
302 | ||
303 | urb->ep = ep; | |
1da177e4 LT |
304 | urb->status = -EINPROGRESS; |
305 | urb->actual_length = 0; | |
1da177e4 LT |
306 | |
307 | /* Lots of sanity checks, so HCDs can rely on clean data | |
308 | * and don't need to duplicate tests | |
309 | */ | |
5b653c79 | 310 | xfertype = usb_endpoint_type(&ep->desc); |
fea34091 AS |
311 | if (xfertype == USB_ENDPOINT_XFER_CONTROL) { |
312 | struct usb_ctrlrequest *setup = | |
313 | (struct usb_ctrlrequest *) urb->setup_packet; | |
314 | ||
315 | if (!setup) | |
316 | return -ENOEXEC; | |
317 | is_out = !(setup->bRequestType & USB_DIR_IN) || | |
318 | !setup->wLength; | |
319 | } else { | |
320 | is_out = usb_endpoint_dir_out(&ep->desc); | |
321 | } | |
322 | ||
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); | |
1da177e4 | 326 | |
5b653c79 AS |
327 | if (xfertype != USB_ENDPOINT_XFER_CONTROL && |
328 | dev->state < USB_STATE_CONFIGURED) | |
1da177e4 LT |
329 | return -ENODEV; |
330 | ||
5b653c79 | 331 | max = le16_to_cpu(ep->desc.wMaxPacketSize); |
1da177e4 LT |
332 | if (max <= 0) { |
333 | dev_dbg(&dev->dev, | |
334 | "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n", | |
5b653c79 | 335 | usb_endpoint_num(&ep->desc), is_out ? "out" : "in", |
1da177e4 LT |
336 | __FUNCTION__, max); |
337 | return -EMSGSIZE; | |
338 | } | |
339 | ||
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. | |
343 | */ | |
5b653c79 | 344 | if (xfertype == USB_ENDPOINT_XFER_ISOC) { |
1da177e4 LT |
345 | int n, len; |
346 | ||
347 | /* "high bandwidth" mode, 1-3 packets/uframe? */ | |
348 | if (dev->speed == USB_SPEED_HIGH) { | |
349 | int mult = 1 + ((max >> 11) & 0x03); | |
350 | max &= 0x07ff; | |
351 | max *= mult; | |
352 | } | |
353 | ||
354 | if (urb->number_of_packets <= 0) | |
355 | return -EINVAL; | |
356 | for (n = 0; n < urb->number_of_packets; n++) { | |
9251644a | 357 | len = urb->iso_frame_desc[n].length; |
1da177e4 LT |
358 | if (len < 0 || len > max) |
359 | return -EMSGSIZE; | |
9251644a ON |
360 | urb->iso_frame_desc[n].status = -EXDEV; |
361 | urb->iso_frame_desc[n].actual_length = 0; | |
1da177e4 LT |
362 | } |
363 | } | |
364 | ||
365 | /* the I/O buffer must be mapped/unmapped, except when length=0 */ | |
366 | if (urb->transfer_buffer_length < 0) | |
367 | return -EMSGSIZE; | |
368 | ||
369 | #ifdef DEBUG | |
370 | /* stuff that drivers shouldn't do, but which shouldn't | |
371 | * cause problems in HCDs if they get it wrong. | |
372 | */ | |
373 | { | |
374 | unsigned int orig_flags = urb->transfer_flags; | |
375 | unsigned int allowed; | |
376 | ||
377 | /* enforce simple/standard policy */ | |
b375a049 | 378 | allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_SETUP_DMA_MAP | |
0b28baaf | 379 | URB_NO_INTERRUPT | URB_DIR_MASK | URB_FREE_BUFFER); |
5b653c79 AS |
380 | switch (xfertype) { |
381 | case USB_ENDPOINT_XFER_BULK: | |
1da177e4 LT |
382 | if (is_out) |
383 | allowed |= URB_ZERO_PACKET; | |
384 | /* FALLTHROUGH */ | |
5b653c79 | 385 | case USB_ENDPOINT_XFER_CONTROL: |
1da177e4 LT |
386 | allowed |= URB_NO_FSBR; /* only affects UHCI */ |
387 | /* FALLTHROUGH */ | |
388 | default: /* all non-iso endpoints */ | |
389 | if (!is_out) | |
390 | allowed |= URB_SHORT_NOT_OK; | |
391 | break; | |
5b653c79 | 392 | case USB_ENDPOINT_XFER_ISOC: |
1da177e4 LT |
393 | allowed |= URB_ISO_ASAP; |
394 | break; | |
395 | } | |
396 | urb->transfer_flags &= allowed; | |
397 | ||
398 | /* fail if submitter gave bogus flags */ | |
399 | if (urb->transfer_flags != orig_flags) { | |
9251644a | 400 | err("BOGUS urb flags, %x --> %x", |
1da177e4 LT |
401 | orig_flags, urb->transfer_flags); |
402 | return -EINVAL; | |
403 | } | |
404 | } | |
405 | #endif | |
406 | /* | |
407 | * Force periodic transfer intervals to be legal values that are | |
408 | * a power of two (so HCDs don't need to). | |
409 | * | |
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). | |
413 | */ | |
5b653c79 AS |
414 | switch (xfertype) { |
415 | case USB_ENDPOINT_XFER_ISOC: | |
416 | case USB_ENDPOINT_XFER_INT: | |
1da177e4 LT |
417 | /* too small? */ |
418 | if (urb->interval <= 0) | |
419 | return -EINVAL; | |
420 | /* too big? */ | |
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; | |
5b653c79 | 426 | max = 1024 * 8; |
1da177e4 LT |
427 | break; |
428 | case USB_SPEED_FULL: /* units are frames/msec */ | |
429 | case USB_SPEED_LOW: | |
5b653c79 | 430 | if (xfertype == USB_ENDPOINT_XFER_INT) { |
1da177e4 LT |
431 | if (urb->interval > 255) |
432 | return -EINVAL; | |
433 | // NOTE ohci only handles up to 32 | |
5b653c79 | 434 | max = 128; |
1da177e4 LT |
435 | } else { |
436 | if (urb->interval > 1024) | |
437 | urb->interval = 1024; | |
438 | // NOTE usb and ohci handle up to 2^15 | |
5b653c79 | 439 | max = 1024; |
1da177e4 LT |
440 | } |
441 | break; | |
442 | default: | |
443 | return -EINVAL; | |
444 | } | |
d617bc83 AS |
445 | /* Round down to a power of 2, no more than max */ |
446 | urb->interval = min(max, 1 << ilog2(urb->interval)); | |
1da177e4 LT |
447 | } |
448 | ||
9251644a | 449 | return usb_hcd_submit_urb(urb, mem_flags); |
1da177e4 | 450 | } |
782e70c6 | 451 | EXPORT_SYMBOL_GPL(usb_submit_urb); |
1da177e4 LT |
452 | |
453 | /*-------------------------------------------------------------------*/ | |
454 | ||
455 | /** | |
456 | * usb_unlink_urb - abort/cancel a transfer request for an endpoint | |
457 | * @urb: pointer to urb describing a previously submitted request, | |
458 | * may be NULL | |
459 | * | |
beafef07 AS |
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 | |
465 | * code). | |
466 | * | |
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. | |
1da177e4 LT |
475 | * |
476 | * Unlinking and Endpoint Queues: | |
477 | * | |
beafef07 AS |
478 | * [The behaviors and guarantees described below do not apply to virtual |
479 | * root hubs but only to endpoint queues for physical USB devices.] | |
480 | * | |
1da177e4 LT |
481 | * Host Controller Drivers (HCDs) place all the URBs for a particular |
482 | * endpoint in a queue. Normally the queue advances as the controller | |
8835f665 | 483 | * hardware processes each request. But when an URB terminates with an |
beafef07 AS |
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. | |
490 | * | |
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. | |
500 | * | |
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. | |
507 | * | |
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 | |
510 | * place. | |
1da177e4 LT |
511 | */ |
512 | int usb_unlink_urb(struct urb *urb) | |
513 | { | |
514 | if (!urb) | |
515 | return -EINVAL; | |
d617bc83 | 516 | if (!urb->dev) |
1da177e4 | 517 | return -ENODEV; |
d617bc83 AS |
518 | if (!urb->ep) |
519 | return -EIDRM; | |
a6d2bb9f | 520 | return usb_hcd_unlink_urb(urb, -ECONNRESET); |
1da177e4 | 521 | } |
782e70c6 | 522 | EXPORT_SYMBOL_GPL(usb_unlink_urb); |
1da177e4 LT |
523 | |
524 | /** | |
525 | * usb_kill_urb - cancel a transfer request and wait for it to finish | |
526 | * @urb: pointer to URB describing a previously submitted request, | |
527 | * may be NULL | |
528 | * | |
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. | |
535 | * | |
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. | |
539 | * | |
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(). | |
543 | */ | |
544 | void usb_kill_urb(struct urb *urb) | |
545 | { | |
1431d2a4 AS |
546 | static DEFINE_MUTEX(reject_mutex); |
547 | ||
e9aa795a | 548 | might_sleep(); |
d617bc83 | 549 | if (!(urb && urb->dev && urb->ep)) |
1da177e4 | 550 | return; |
1431d2a4 | 551 | mutex_lock(&reject_mutex); |
1da177e4 | 552 | ++urb->reject; |
1431d2a4 | 553 | mutex_unlock(&reject_mutex); |
1da177e4 | 554 | |
a6d2bb9f | 555 | usb_hcd_unlink_urb(urb, -ENOENT); |
1da177e4 LT |
556 | wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); |
557 | ||
1431d2a4 | 558 | mutex_lock(&reject_mutex); |
1da177e4 | 559 | --urb->reject; |
1431d2a4 | 560 | mutex_unlock(&reject_mutex); |
1da177e4 | 561 | } |
782e70c6 | 562 | EXPORT_SYMBOL_GPL(usb_kill_urb); |
1da177e4 | 563 | |
51a2f077 ON |
564 | /** |
565 | * usb_kill_anchored_urbs - cancel transfer requests en masse | |
566 | * @anchor: anchor the requests are bound to | |
567 | * | |
568 | * this allows all outstanding URBs to be killed starting | |
569 | * from the back of the queue | |
570 | */ | |
571 | void usb_kill_anchored_urbs(struct usb_anchor *anchor) | |
572 | { | |
573 | struct urb *victim; | |
574 | ||
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*/ | |
579 | usb_get_urb(victim); | |
580 | spin_unlock_irq(&anchor->lock); | |
581 | /* this will unanchor the URB */ | |
582 | usb_kill_urb(victim); | |
583 | usb_put_urb(victim); | |
584 | spin_lock_irq(&anchor->lock); | |
585 | } | |
586 | spin_unlock_irq(&anchor->lock); | |
587 | } | |
588 | EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs); | |
589 | ||
590 | /** | |
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 | |
594 | * | |
595 | * Call this is you want to be sure all an anchor's | |
596 | * URBs have finished | |
597 | */ | |
598 | int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor, | |
599 | unsigned int timeout) | |
600 | { | |
601 | return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list), | |
602 | msecs_to_jiffies(timeout)); | |
603 | } | |
604 | EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout); |