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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 | ||
6a2839be | 13 | |
1da177e4 LT |
14 | static void urb_destroy(struct kref *kref) |
15 | { | |
16 | struct urb *urb = to_urb(kref); | |
51a2f077 | 17 | |
8b3b01c8 MH |
18 | if (urb->transfer_flags & URB_FREE_BUFFER) |
19 | kfree(urb->transfer_buffer); | |
20 | ||
1da177e4 LT |
21 | kfree(urb); |
22 | } | |
23 | ||
24 | /** | |
25 | * usb_init_urb - initializes a urb so that it can be used by a USB driver | |
26 | * @urb: pointer to the urb to initialize | |
27 | * | |
28 | * Initializes a urb so that the USB subsystem can use it properly. | |
29 | * | |
30 | * If a urb is created with a call to usb_alloc_urb() it is not | |
31 | * necessary to call this function. Only use this if you allocate the | |
32 | * space for a struct urb on your own. If you call this function, be | |
33 | * careful when freeing the memory for your urb that it is no longer in | |
34 | * use by the USB core. | |
35 | * | |
36 | * Only use this function if you _really_ understand what you are doing. | |
37 | */ | |
38 | void usb_init_urb(struct urb *urb) | |
39 | { | |
40 | if (urb) { | |
41 | memset(urb, 0, sizeof(*urb)); | |
42 | kref_init(&urb->kref); | |
51a2f077 | 43 | INIT_LIST_HEAD(&urb->anchor_list); |
1da177e4 LT |
44 | } |
45 | } | |
782e70c6 | 46 | EXPORT_SYMBOL_GPL(usb_init_urb); |
1da177e4 LT |
47 | |
48 | /** | |
49 | * usb_alloc_urb - creates a new urb for a USB driver to use | |
50 | * @iso_packets: number of iso packets for this urb | |
51 | * @mem_flags: the type of memory to allocate, see kmalloc() for a list of | |
52 | * valid options for this. | |
53 | * | |
54 | * Creates an urb for the USB driver to use, initializes a few internal | |
55 | * structures, incrementes the usage counter, and returns a pointer to it. | |
56 | * | |
57 | * If no memory is available, NULL is returned. | |
58 | * | |
59 | * If the driver want to use this urb for interrupt, control, or bulk | |
60 | * endpoints, pass '0' as the number of iso packets. | |
61 | * | |
62 | * The driver must call usb_free_urb() when it is finished with the urb. | |
63 | */ | |
55016f10 | 64 | struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags) |
1da177e4 LT |
65 | { |
66 | struct urb *urb; | |
67 | ||
ec17cf1c | 68 | urb = kmalloc(sizeof(struct urb) + |
1da177e4 LT |
69 | iso_packets * sizeof(struct usb_iso_packet_descriptor), |
70 | mem_flags); | |
71 | if (!urb) { | |
69a85942 | 72 | printk(KERN_ERR "alloc_urb: kmalloc failed\n"); |
1da177e4 LT |
73 | return NULL; |
74 | } | |
75 | usb_init_urb(urb); | |
76 | return urb; | |
77 | } | |
782e70c6 | 78 | EXPORT_SYMBOL_GPL(usb_alloc_urb); |
1da177e4 LT |
79 | |
80 | /** | |
81 | * usb_free_urb - frees the memory used by a urb when all users of it are finished | |
82 | * @urb: pointer to the urb to free, may be NULL | |
83 | * | |
84 | * Must be called when a user of a urb is finished with it. When the last user | |
85 | * of the urb calls this function, the memory of the urb is freed. | |
86 | * | |
2870fde7 RV |
87 | * Note: The transfer buffer associated with the urb is not freed unless the |
88 | * URB_FREE_BUFFER transfer flag is set. | |
1da177e4 LT |
89 | */ |
90 | void usb_free_urb(struct urb *urb) | |
91 | { | |
92 | if (urb) | |
93 | kref_put(&urb->kref, urb_destroy); | |
94 | } | |
782e70c6 | 95 | EXPORT_SYMBOL_GPL(usb_free_urb); |
1da177e4 LT |
96 | |
97 | /** | |
98 | * usb_get_urb - increments the reference count of the urb | |
99 | * @urb: pointer to the urb to modify, may be NULL | |
100 | * | |
101 | * This must be called whenever a urb is transferred from a device driver to a | |
102 | * host controller driver. This allows proper reference counting to happen | |
103 | * for urbs. | |
104 | * | |
105 | * A pointer to the urb with the incremented reference counter is returned. | |
106 | */ | |
2c044a48 | 107 | struct urb *usb_get_urb(struct urb *urb) |
1da177e4 LT |
108 | { |
109 | if (urb) | |
110 | kref_get(&urb->kref); | |
111 | return urb; | |
112 | } | |
782e70c6 | 113 | EXPORT_SYMBOL_GPL(usb_get_urb); |
51a2f077 ON |
114 | |
115 | /** | |
116 | * usb_anchor_urb - anchors an URB while it is processed | |
117 | * @urb: pointer to the urb to anchor | |
118 | * @anchor: pointer to the anchor | |
119 | * | |
120 | * This can be called to have access to URBs which are to be executed | |
121 | * without bothering to track them | |
122 | */ | |
123 | void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor) | |
124 | { | |
125 | unsigned long flags; | |
126 | ||
127 | spin_lock_irqsave(&anchor->lock, flags); | |
128 | usb_get_urb(urb); | |
129 | list_add_tail(&urb->anchor_list, &anchor->urb_list); | |
130 | urb->anchor = anchor; | |
6a2839be ON |
131 | |
132 | if (unlikely(anchor->poisoned)) { | |
49367d8f | 133 | atomic_inc(&urb->reject); |
6a2839be ON |
134 | } |
135 | ||
51a2f077 ON |
136 | spin_unlock_irqrestore(&anchor->lock, flags); |
137 | } | |
138 | EXPORT_SYMBOL_GPL(usb_anchor_urb); | |
139 | ||
140 | /** | |
141 | * usb_unanchor_urb - unanchors an URB | |
142 | * @urb: pointer to the urb to anchor | |
143 | * | |
144 | * Call this to stop the system keeping track of this URB | |
145 | */ | |
146 | void usb_unanchor_urb(struct urb *urb) | |
147 | { | |
148 | unsigned long flags; | |
149 | struct usb_anchor *anchor; | |
150 | ||
151 | if (!urb) | |
152 | return; | |
153 | ||
154 | anchor = urb->anchor; | |
155 | if (!anchor) | |
156 | return; | |
157 | ||
158 | spin_lock_irqsave(&anchor->lock, flags); | |
159 | if (unlikely(anchor != urb->anchor)) { | |
160 | /* we've lost the race to another thread */ | |
161 | spin_unlock_irqrestore(&anchor->lock, flags); | |
162 | return; | |
163 | } | |
164 | urb->anchor = NULL; | |
165 | list_del(&urb->anchor_list); | |
166 | spin_unlock_irqrestore(&anchor->lock, flags); | |
167 | usb_put_urb(urb); | |
168 | if (list_empty(&anchor->urb_list)) | |
169 | wake_up(&anchor->wait); | |
170 | } | |
171 | EXPORT_SYMBOL_GPL(usb_unanchor_urb); | |
172 | ||
1da177e4 LT |
173 | /*-------------------------------------------------------------------*/ |
174 | ||
175 | /** | |
176 | * usb_submit_urb - issue an asynchronous transfer request for an endpoint | |
177 | * @urb: pointer to the urb describing the request | |
178 | * @mem_flags: the type of memory to allocate, see kmalloc() for a list | |
179 | * of valid options for this. | |
180 | * | |
181 | * This submits a transfer request, and transfers control of the URB | |
182 | * describing that request to the USB subsystem. Request completion will | |
183 | * be indicated later, asynchronously, by calling the completion handler. | |
184 | * The three types of completion are success, error, and unlink | |
2c044a48 | 185 | * (a software-induced fault, also called "request cancellation"). |
1da177e4 LT |
186 | * |
187 | * URBs may be submitted in interrupt context. | |
188 | * | |
189 | * The caller must have correctly initialized the URB before submitting | |
190 | * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are | |
191 | * available to ensure that most fields are correctly initialized, for | |
192 | * the particular kind of transfer, although they will not initialize | |
193 | * any transfer flags. | |
194 | * | |
195 | * Successful submissions return 0; otherwise this routine returns a | |
196 | * negative error number. If the submission is successful, the complete() | |
197 | * callback from the URB will be called exactly once, when the USB core and | |
198 | * Host Controller Driver (HCD) are finished with the URB. When the completion | |
199 | * function is called, control of the URB is returned to the device | |
200 | * driver which issued the request. The completion handler may then | |
201 | * immediately free or reuse that URB. | |
202 | * | |
203 | * With few exceptions, USB device drivers should never access URB fields | |
204 | * provided by usbcore or the HCD until its complete() is called. | |
205 | * The exceptions relate to periodic transfer scheduling. For both | |
206 | * interrupt and isochronous urbs, as part of successful URB submission | |
207 | * urb->interval is modified to reflect the actual transfer period used | |
208 | * (normally some power of two units). And for isochronous urbs, | |
209 | * urb->start_frame is modified to reflect when the URB's transfers were | |
210 | * scheduled to start. Not all isochronous transfer scheduling policies | |
211 | * will work, but most host controller drivers should easily handle ISO | |
212 | * queues going from now until 10-200 msec into the future. | |
213 | * | |
214 | * For control endpoints, the synchronous usb_control_msg() call is | |
215 | * often used (in non-interrupt context) instead of this call. | |
216 | * That is often used through convenience wrappers, for the requests | |
217 | * that are standardized in the USB 2.0 specification. For bulk | |
218 | * endpoints, a synchronous usb_bulk_msg() call is available. | |
219 | * | |
220 | * Request Queuing: | |
221 | * | |
222 | * URBs may be submitted to endpoints before previous ones complete, to | |
223 | * minimize the impact of interrupt latencies and system overhead on data | |
224 | * throughput. With that queuing policy, an endpoint's queue would never | |
225 | * be empty. This is required for continuous isochronous data streams, | |
226 | * and may also be required for some kinds of interrupt transfers. Such | |
227 | * queuing also maximizes bandwidth utilization by letting USB controllers | |
228 | * start work on later requests before driver software has finished the | |
229 | * completion processing for earlier (successful) requests. | |
230 | * | |
231 | * As of Linux 2.6, all USB endpoint transfer queues support depths greater | |
232 | * than one. This was previously a HCD-specific behavior, except for ISO | |
233 | * transfers. Non-isochronous endpoint queues are inactive during cleanup | |
093cf723 | 234 | * after faults (transfer errors or cancellation). |
1da177e4 LT |
235 | * |
236 | * Reserved Bandwidth Transfers: | |
237 | * | |
238 | * Periodic transfers (interrupt or isochronous) are performed repeatedly, | |
239 | * using the interval specified in the urb. Submitting the first urb to | |
240 | * the endpoint reserves the bandwidth necessary to make those transfers. | |
241 | * If the USB subsystem can't allocate sufficient bandwidth to perform | |
242 | * the periodic request, submitting such a periodic request should fail. | |
243 | * | |
244 | * Device drivers must explicitly request that repetition, by ensuring that | |
245 | * some URB is always on the endpoint's queue (except possibly for short | |
246 | * periods during completion callacks). When there is no longer an urb | |
247 | * queued, the endpoint's bandwidth reservation is canceled. This means | |
248 | * drivers can use their completion handlers to ensure they keep bandwidth | |
249 | * they need, by reinitializing and resubmitting the just-completed urb | |
250 | * until the driver longer needs that periodic bandwidth. | |
251 | * | |
252 | * Memory Flags: | |
253 | * | |
254 | * The general rules for how to decide which mem_flags to use | |
255 | * are the same as for kmalloc. There are four | |
256 | * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and | |
257 | * GFP_ATOMIC. | |
258 | * | |
259 | * GFP_NOFS is not ever used, as it has not been implemented yet. | |
260 | * | |
261 | * GFP_ATOMIC is used when | |
262 | * (a) you are inside a completion handler, an interrupt, bottom half, | |
263 | * tasklet or timer, or | |
264 | * (b) you are holding a spinlock or rwlock (does not apply to | |
265 | * semaphores), or | |
266 | * (c) current->state != TASK_RUNNING, this is the case only after | |
267 | * you've changed it. | |
2c044a48 | 268 | * |
1da177e4 LT |
269 | * GFP_NOIO is used in the block io path and error handling of storage |
270 | * devices. | |
271 | * | |
272 | * All other situations use GFP_KERNEL. | |
273 | * | |
274 | * Some more specific rules for mem_flags can be inferred, such as | |
275 | * (1) start_xmit, timeout, and receive methods of network drivers must | |
276 | * use GFP_ATOMIC (they are called with a spinlock held); | |
277 | * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also | |
278 | * called with a spinlock held); | |
279 | * (3) If you use a kernel thread with a network driver you must use | |
280 | * GFP_NOIO, unless (b) or (c) apply; | |
281 | * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c) | |
282 | * apply or your are in a storage driver's block io path; | |
283 | * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and | |
284 | * (6) changing firmware on a running storage or net device uses | |
285 | * GFP_NOIO, unless b) or c) apply | |
286 | * | |
287 | */ | |
55016f10 | 288 | int usb_submit_urb(struct urb *urb, gfp_t mem_flags) |
1da177e4 | 289 | { |
5b653c79 AS |
290 | int xfertype, max; |
291 | struct usb_device *dev; | |
292 | struct usb_host_endpoint *ep; | |
293 | int is_out; | |
1da177e4 LT |
294 | |
295 | if (!urb || urb->hcpriv || !urb->complete) | |
296 | return -EINVAL; | |
2c044a48 | 297 | dev = urb->dev; |
6da9c990 | 298 | if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED)) |
1da177e4 | 299 | return -ENODEV; |
1da177e4 | 300 | |
5b653c79 AS |
301 | /* For now, get the endpoint from the pipe. Eventually drivers |
302 | * will be required to set urb->ep directly and we will eliminate | |
303 | * urb->pipe. | |
304 | */ | |
305 | ep = (usb_pipein(urb->pipe) ? dev->ep_in : dev->ep_out) | |
306 | [usb_pipeendpoint(urb->pipe)]; | |
307 | if (!ep) | |
308 | return -ENOENT; | |
309 | ||
310 | urb->ep = ep; | |
1da177e4 LT |
311 | urb->status = -EINPROGRESS; |
312 | urb->actual_length = 0; | |
1da177e4 LT |
313 | |
314 | /* Lots of sanity checks, so HCDs can rely on clean data | |
315 | * and don't need to duplicate tests | |
316 | */ | |
5b653c79 | 317 | xfertype = usb_endpoint_type(&ep->desc); |
fea34091 AS |
318 | if (xfertype == USB_ENDPOINT_XFER_CONTROL) { |
319 | struct usb_ctrlrequest *setup = | |
320 | (struct usb_ctrlrequest *) urb->setup_packet; | |
321 | ||
322 | if (!setup) | |
323 | return -ENOEXEC; | |
324 | is_out = !(setup->bRequestType & USB_DIR_IN) || | |
325 | !setup->wLength; | |
326 | } else { | |
327 | is_out = usb_endpoint_dir_out(&ep->desc); | |
328 | } | |
329 | ||
330 | /* Cache the direction for later use */ | |
331 | urb->transfer_flags = (urb->transfer_flags & ~URB_DIR_MASK) | | |
332 | (is_out ? URB_DIR_OUT : URB_DIR_IN); | |
1da177e4 | 333 | |
5b653c79 AS |
334 | if (xfertype != USB_ENDPOINT_XFER_CONTROL && |
335 | dev->state < USB_STATE_CONFIGURED) | |
1da177e4 LT |
336 | return -ENODEV; |
337 | ||
5b653c79 | 338 | max = le16_to_cpu(ep->desc.wMaxPacketSize); |
1da177e4 LT |
339 | if (max <= 0) { |
340 | dev_dbg(&dev->dev, | |
341 | "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n", | |
5b653c79 | 342 | usb_endpoint_num(&ep->desc), is_out ? "out" : "in", |
441b62c1 | 343 | __func__, max); |
1da177e4 LT |
344 | return -EMSGSIZE; |
345 | } | |
346 | ||
347 | /* periodic transfers limit size per frame/uframe, | |
348 | * but drivers only control those sizes for ISO. | |
349 | * while we're checking, initialize return status. | |
350 | */ | |
5b653c79 | 351 | if (xfertype == USB_ENDPOINT_XFER_ISOC) { |
1da177e4 LT |
352 | int n, len; |
353 | ||
354 | /* "high bandwidth" mode, 1-3 packets/uframe? */ | |
355 | if (dev->speed == USB_SPEED_HIGH) { | |
356 | int mult = 1 + ((max >> 11) & 0x03); | |
357 | max &= 0x07ff; | |
358 | max *= mult; | |
359 | } | |
360 | ||
2c044a48 | 361 | if (urb->number_of_packets <= 0) |
1da177e4 LT |
362 | return -EINVAL; |
363 | for (n = 0; n < urb->number_of_packets; n++) { | |
9251644a | 364 | len = urb->iso_frame_desc[n].length; |
2c044a48 | 365 | if (len < 0 || len > max) |
1da177e4 | 366 | return -EMSGSIZE; |
9251644a ON |
367 | urb->iso_frame_desc[n].status = -EXDEV; |
368 | urb->iso_frame_desc[n].actual_length = 0; | |
1da177e4 LT |
369 | } |
370 | } | |
371 | ||
372 | /* the I/O buffer must be mapped/unmapped, except when length=0 */ | |
71d2718f | 373 | if (urb->transfer_buffer_length > INT_MAX) |
1da177e4 LT |
374 | return -EMSGSIZE; |
375 | ||
376 | #ifdef DEBUG | |
377 | /* stuff that drivers shouldn't do, but which shouldn't | |
378 | * cause problems in HCDs if they get it wrong. | |
379 | */ | |
380 | { | |
381 | unsigned int orig_flags = urb->transfer_flags; | |
382 | unsigned int allowed; | |
383 | ||
384 | /* enforce simple/standard policy */ | |
b375a049 | 385 | allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_SETUP_DMA_MAP | |
0b28baaf | 386 | URB_NO_INTERRUPT | URB_DIR_MASK | URB_FREE_BUFFER); |
5b653c79 AS |
387 | switch (xfertype) { |
388 | case USB_ENDPOINT_XFER_BULK: | |
1da177e4 LT |
389 | if (is_out) |
390 | allowed |= URB_ZERO_PACKET; | |
391 | /* FALLTHROUGH */ | |
5b653c79 | 392 | case USB_ENDPOINT_XFER_CONTROL: |
1da177e4 LT |
393 | allowed |= URB_NO_FSBR; /* only affects UHCI */ |
394 | /* FALLTHROUGH */ | |
395 | default: /* all non-iso endpoints */ | |
396 | if (!is_out) | |
397 | allowed |= URB_SHORT_NOT_OK; | |
398 | break; | |
5b653c79 | 399 | case USB_ENDPOINT_XFER_ISOC: |
1da177e4 LT |
400 | allowed |= URB_ISO_ASAP; |
401 | break; | |
402 | } | |
403 | urb->transfer_flags &= allowed; | |
404 | ||
405 | /* fail if submitter gave bogus flags */ | |
406 | if (urb->transfer_flags != orig_flags) { | |
69a85942 | 407 | dev_err(&dev->dev, "BOGUS urb flags, %x --> %x\n", |
1da177e4 LT |
408 | orig_flags, urb->transfer_flags); |
409 | return -EINVAL; | |
410 | } | |
411 | } | |
412 | #endif | |
413 | /* | |
414 | * Force periodic transfer intervals to be legal values that are | |
415 | * a power of two (so HCDs don't need to). | |
416 | * | |
417 | * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC | |
418 | * supports different values... this uses EHCI/UHCI defaults (and | |
419 | * EHCI can use smaller non-default values). | |
420 | */ | |
5b653c79 AS |
421 | switch (xfertype) { |
422 | case USB_ENDPOINT_XFER_ISOC: | |
423 | case USB_ENDPOINT_XFER_INT: | |
1da177e4 LT |
424 | /* too small? */ |
425 | if (urb->interval <= 0) | |
426 | return -EINVAL; | |
427 | /* too big? */ | |
428 | switch (dev->speed) { | |
429 | case USB_SPEED_HIGH: /* units are microframes */ | |
2c044a48 | 430 | /* NOTE usb handles 2^15 */ |
1da177e4 LT |
431 | if (urb->interval > (1024 * 8)) |
432 | urb->interval = 1024 * 8; | |
5b653c79 | 433 | max = 1024 * 8; |
1da177e4 LT |
434 | break; |
435 | case USB_SPEED_FULL: /* units are frames/msec */ | |
436 | case USB_SPEED_LOW: | |
5b653c79 | 437 | if (xfertype == USB_ENDPOINT_XFER_INT) { |
1da177e4 LT |
438 | if (urb->interval > 255) |
439 | return -EINVAL; | |
2c044a48 | 440 | /* NOTE ohci only handles up to 32 */ |
5b653c79 | 441 | max = 128; |
1da177e4 LT |
442 | } else { |
443 | if (urb->interval > 1024) | |
444 | urb->interval = 1024; | |
2c044a48 | 445 | /* NOTE usb and ohci handle up to 2^15 */ |
5b653c79 | 446 | max = 1024; |
1da177e4 LT |
447 | } |
448 | break; | |
449 | default: | |
450 | return -EINVAL; | |
451 | } | |
d617bc83 AS |
452 | /* Round down to a power of 2, no more than max */ |
453 | urb->interval = min(max, 1 << ilog2(urb->interval)); | |
1da177e4 LT |
454 | } |
455 | ||
9251644a | 456 | return usb_hcd_submit_urb(urb, mem_flags); |
1da177e4 | 457 | } |
782e70c6 | 458 | EXPORT_SYMBOL_GPL(usb_submit_urb); |
1da177e4 LT |
459 | |
460 | /*-------------------------------------------------------------------*/ | |
461 | ||
462 | /** | |
463 | * usb_unlink_urb - abort/cancel a transfer request for an endpoint | |
464 | * @urb: pointer to urb describing a previously submitted request, | |
465 | * may be NULL | |
466 | * | |
beafef07 AS |
467 | * This routine cancels an in-progress request. URBs complete only once |
468 | * per submission, and may be canceled only once per submission. | |
469 | * Successful cancellation means termination of @urb will be expedited | |
470 | * and the completion handler will be called with a status code | |
471 | * indicating that the request has been canceled (rather than any other | |
472 | * code). | |
473 | * | |
cde217a5 AS |
474 | * Drivers should not call this routine or related routines, such as |
475 | * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect | |
476 | * method has returned. The disconnect function should synchronize with | |
477 | * a driver's I/O routines to insure that all URB-related activity has | |
478 | * completed before it returns. | |
479 | * | |
beafef07 AS |
480 | * This request is always asynchronous. Success is indicated by |
481 | * returning -EINPROGRESS, at which time the URB will probably not yet | |
482 | * have been given back to the device driver. When it is eventually | |
483 | * called, the completion function will see @urb->status == -ECONNRESET. | |
484 | * Failure is indicated by usb_unlink_urb() returning any other value. | |
485 | * Unlinking will fail when @urb is not currently "linked" (i.e., it was | |
486 | * never submitted, or it was unlinked before, or the hardware is already | |
487 | * finished with it), even if the completion handler has not yet run. | |
1da177e4 LT |
488 | * |
489 | * Unlinking and Endpoint Queues: | |
490 | * | |
beafef07 AS |
491 | * [The behaviors and guarantees described below do not apply to virtual |
492 | * root hubs but only to endpoint queues for physical USB devices.] | |
493 | * | |
1da177e4 LT |
494 | * Host Controller Drivers (HCDs) place all the URBs for a particular |
495 | * endpoint in a queue. Normally the queue advances as the controller | |
8835f665 | 496 | * hardware processes each request. But when an URB terminates with an |
beafef07 AS |
497 | * error its queue generally stops (see below), at least until that URB's |
498 | * completion routine returns. It is guaranteed that a stopped queue | |
499 | * will not restart until all its unlinked URBs have been fully retired, | |
500 | * with their completion routines run, even if that's not until some time | |
501 | * after the original completion handler returns. The same behavior and | |
502 | * guarantee apply when an URB terminates because it was unlinked. | |
503 | * | |
504 | * Bulk and interrupt endpoint queues are guaranteed to stop whenever an | |
505 | * URB terminates with any sort of error, including -ECONNRESET, -ENOENT, | |
506 | * and -EREMOTEIO. Control endpoint queues behave the same way except | |
507 | * that they are not guaranteed to stop for -EREMOTEIO errors. Queues | |
508 | * for isochronous endpoints are treated differently, because they must | |
509 | * advance at fixed rates. Such queues do not stop when an URB | |
510 | * encounters an error or is unlinked. An unlinked isochronous URB may | |
511 | * leave a gap in the stream of packets; it is undefined whether such | |
512 | * gaps can be filled in. | |
513 | * | |
514 | * Note that early termination of an URB because a short packet was | |
515 | * received will generate a -EREMOTEIO error if and only if the | |
516 | * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device | |
517 | * drivers can build deep queues for large or complex bulk transfers | |
518 | * and clean them up reliably after any sort of aborted transfer by | |
519 | * unlinking all pending URBs at the first fault. | |
520 | * | |
521 | * When a control URB terminates with an error other than -EREMOTEIO, it | |
522 | * is quite likely that the status stage of the transfer will not take | |
523 | * place. | |
1da177e4 LT |
524 | */ |
525 | int usb_unlink_urb(struct urb *urb) | |
526 | { | |
527 | if (!urb) | |
528 | return -EINVAL; | |
d617bc83 | 529 | if (!urb->dev) |
1da177e4 | 530 | return -ENODEV; |
d617bc83 AS |
531 | if (!urb->ep) |
532 | return -EIDRM; | |
a6d2bb9f | 533 | return usb_hcd_unlink_urb(urb, -ECONNRESET); |
1da177e4 | 534 | } |
782e70c6 | 535 | EXPORT_SYMBOL_GPL(usb_unlink_urb); |
1da177e4 LT |
536 | |
537 | /** | |
538 | * usb_kill_urb - cancel a transfer request and wait for it to finish | |
539 | * @urb: pointer to URB describing a previously submitted request, | |
540 | * may be NULL | |
541 | * | |
542 | * This routine cancels an in-progress request. It is guaranteed that | |
543 | * upon return all completion handlers will have finished and the URB | |
544 | * will be totally idle and available for reuse. These features make | |
545 | * this an ideal way to stop I/O in a disconnect() callback or close() | |
546 | * function. If the request has not already finished or been unlinked | |
547 | * the completion handler will see urb->status == -ENOENT. | |
548 | * | |
549 | * While the routine is running, attempts to resubmit the URB will fail | |
550 | * with error -EPERM. Thus even if the URB's completion handler always | |
551 | * tries to resubmit, it will not succeed and the URB will become idle. | |
552 | * | |
553 | * This routine may not be used in an interrupt context (such as a bottom | |
554 | * half or a completion handler), or when holding a spinlock, or in other | |
555 | * situations where the caller can't schedule(). | |
cde217a5 AS |
556 | * |
557 | * This routine should not be called by a driver after its disconnect | |
558 | * method has returned. | |
1da177e4 LT |
559 | */ |
560 | void usb_kill_urb(struct urb *urb) | |
561 | { | |
e9aa795a | 562 | might_sleep(); |
d617bc83 | 563 | if (!(urb && urb->dev && urb->ep)) |
1da177e4 | 564 | return; |
49367d8f | 565 | atomic_inc(&urb->reject); |
1da177e4 | 566 | |
a6d2bb9f | 567 | usb_hcd_unlink_urb(urb, -ENOENT); |
1da177e4 LT |
568 | wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); |
569 | ||
49367d8f | 570 | atomic_dec(&urb->reject); |
1da177e4 | 571 | } |
782e70c6 | 572 | EXPORT_SYMBOL_GPL(usb_kill_urb); |
1da177e4 | 573 | |
55b447bf ON |
574 | /** |
575 | * usb_poison_urb - reliably kill a transfer and prevent further use of an URB | |
576 | * @urb: pointer to URB describing a previously submitted request, | |
577 | * may be NULL | |
578 | * | |
579 | * This routine cancels an in-progress request. It is guaranteed that | |
580 | * upon return all completion handlers will have finished and the URB | |
581 | * will be totally idle and cannot be reused. These features make | |
582 | * this an ideal way to stop I/O in a disconnect() callback. | |
583 | * If the request has not already finished or been unlinked | |
584 | * the completion handler will see urb->status == -ENOENT. | |
585 | * | |
586 | * After and while the routine runs, attempts to resubmit the URB will fail | |
587 | * with error -EPERM. Thus even if the URB's completion handler always | |
588 | * tries to resubmit, it will not succeed and the URB will become idle. | |
589 | * | |
590 | * This routine may not be used in an interrupt context (such as a bottom | |
591 | * half or a completion handler), or when holding a spinlock, or in other | |
592 | * situations where the caller can't schedule(). | |
cde217a5 AS |
593 | * |
594 | * This routine should not be called by a driver after its disconnect | |
595 | * method has returned. | |
55b447bf ON |
596 | */ |
597 | void usb_poison_urb(struct urb *urb) | |
598 | { | |
599 | might_sleep(); | |
600 | if (!(urb && urb->dev && urb->ep)) | |
601 | return; | |
49367d8f | 602 | atomic_inc(&urb->reject); |
55b447bf ON |
603 | |
604 | usb_hcd_unlink_urb(urb, -ENOENT); | |
605 | wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); | |
606 | } | |
607 | EXPORT_SYMBOL_GPL(usb_poison_urb); | |
608 | ||
609 | void usb_unpoison_urb(struct urb *urb) | |
610 | { | |
611 | if (!urb) | |
612 | return; | |
613 | ||
49367d8f | 614 | atomic_dec(&urb->reject); |
55b447bf ON |
615 | } |
616 | EXPORT_SYMBOL_GPL(usb_unpoison_urb); | |
617 | ||
51a2f077 ON |
618 | /** |
619 | * usb_kill_anchored_urbs - cancel transfer requests en masse | |
620 | * @anchor: anchor the requests are bound to | |
621 | * | |
622 | * this allows all outstanding URBs to be killed starting | |
623 | * from the back of the queue | |
cde217a5 AS |
624 | * |
625 | * This routine should not be called by a driver after its disconnect | |
626 | * method has returned. | |
51a2f077 ON |
627 | */ |
628 | void usb_kill_anchored_urbs(struct usb_anchor *anchor) | |
629 | { | |
630 | struct urb *victim; | |
631 | ||
632 | spin_lock_irq(&anchor->lock); | |
633 | while (!list_empty(&anchor->urb_list)) { | |
2c044a48 GKH |
634 | victim = list_entry(anchor->urb_list.prev, struct urb, |
635 | anchor_list); | |
51a2f077 ON |
636 | /* we must make sure the URB isn't freed before we kill it*/ |
637 | usb_get_urb(victim); | |
638 | spin_unlock_irq(&anchor->lock); | |
639 | /* this will unanchor the URB */ | |
640 | usb_kill_urb(victim); | |
641 | usb_put_urb(victim); | |
642 | spin_lock_irq(&anchor->lock); | |
643 | } | |
644 | spin_unlock_irq(&anchor->lock); | |
645 | } | |
646 | EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs); | |
647 | ||
6a2839be ON |
648 | |
649 | /** | |
650 | * usb_poison_anchored_urbs - cease all traffic from an anchor | |
651 | * @anchor: anchor the requests are bound to | |
652 | * | |
653 | * this allows all outstanding URBs to be poisoned starting | |
654 | * from the back of the queue. Newly added URBs will also be | |
655 | * poisoned | |
cde217a5 AS |
656 | * |
657 | * This routine should not be called by a driver after its disconnect | |
658 | * method has returned. | |
6a2839be ON |
659 | */ |
660 | void usb_poison_anchored_urbs(struct usb_anchor *anchor) | |
661 | { | |
662 | struct urb *victim; | |
663 | ||
664 | spin_lock_irq(&anchor->lock); | |
665 | anchor->poisoned = 1; | |
666 | while (!list_empty(&anchor->urb_list)) { | |
667 | victim = list_entry(anchor->urb_list.prev, struct urb, | |
668 | anchor_list); | |
669 | /* we must make sure the URB isn't freed before we kill it*/ | |
670 | usb_get_urb(victim); | |
671 | spin_unlock_irq(&anchor->lock); | |
672 | /* this will unanchor the URB */ | |
673 | usb_poison_urb(victim); | |
674 | usb_put_urb(victim); | |
675 | spin_lock_irq(&anchor->lock); | |
676 | } | |
677 | spin_unlock_irq(&anchor->lock); | |
678 | } | |
679 | EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs); | |
cde217a5 | 680 | |
856395d6 ON |
681 | /** |
682 | * usb_unpoison_anchored_urbs - let an anchor be used successfully again | |
683 | * @anchor: anchor the requests are bound to | |
684 | * | |
685 | * Reverses the effect of usb_poison_anchored_urbs | |
686 | * the anchor can be used normally after it returns | |
687 | */ | |
688 | void usb_unpoison_anchored_urbs(struct usb_anchor *anchor) | |
689 | { | |
690 | unsigned long flags; | |
691 | struct urb *lazarus; | |
692 | ||
693 | spin_lock_irqsave(&anchor->lock, flags); | |
694 | list_for_each_entry(lazarus, &anchor->urb_list, anchor_list) { | |
695 | usb_unpoison_urb(lazarus); | |
696 | } | |
697 | anchor->poisoned = 0; | |
698 | spin_unlock_irqrestore(&anchor->lock, flags); | |
699 | } | |
700 | EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs); | |
eda76959 ON |
701 | /** |
702 | * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse | |
703 | * @anchor: anchor the requests are bound to | |
704 | * | |
705 | * this allows all outstanding URBs to be unlinked starting | |
706 | * from the back of the queue. This function is asynchronous. | |
707 | * The unlinking is just tiggered. It may happen after this | |
708 | * function has returned. | |
cde217a5 AS |
709 | * |
710 | * This routine should not be called by a driver after its disconnect | |
711 | * method has returned. | |
eda76959 ON |
712 | */ |
713 | void usb_unlink_anchored_urbs(struct usb_anchor *anchor) | |
714 | { | |
715 | struct urb *victim; | |
77571f05 | 716 | unsigned long flags; |
eda76959 | 717 | |
77571f05 | 718 | spin_lock_irqsave(&anchor->lock, flags); |
eda76959 ON |
719 | while (!list_empty(&anchor->urb_list)) { |
720 | victim = list_entry(anchor->urb_list.prev, struct urb, | |
721 | anchor_list); | |
77571f05 ON |
722 | usb_get_urb(victim); |
723 | spin_unlock_irqrestore(&anchor->lock, flags); | |
eda76959 ON |
724 | /* this will unanchor the URB */ |
725 | usb_unlink_urb(victim); | |
77571f05 ON |
726 | usb_put_urb(victim); |
727 | spin_lock_irqsave(&anchor->lock, flags); | |
eda76959 | 728 | } |
77571f05 | 729 | spin_unlock_irqrestore(&anchor->lock, flags); |
eda76959 ON |
730 | } |
731 | EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs); | |
732 | ||
51a2f077 ON |
733 | /** |
734 | * usb_wait_anchor_empty_timeout - wait for an anchor to be unused | |
735 | * @anchor: the anchor you want to become unused | |
736 | * @timeout: how long you are willing to wait in milliseconds | |
737 | * | |
738 | * Call this is you want to be sure all an anchor's | |
739 | * URBs have finished | |
740 | */ | |
741 | int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor, | |
742 | unsigned int timeout) | |
743 | { | |
744 | return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list), | |
745 | msecs_to_jiffies(timeout)); | |
746 | } | |
747 | EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout); | |
19876252 ON |
748 | |
749 | /** | |
750 | * usb_get_from_anchor - get an anchor's oldest urb | |
751 | * @anchor: the anchor whose urb you want | |
752 | * | |
753 | * this will take the oldest urb from an anchor, | |
754 | * unanchor and return it | |
755 | */ | |
756 | struct urb *usb_get_from_anchor(struct usb_anchor *anchor) | |
757 | { | |
758 | struct urb *victim; | |
759 | unsigned long flags; | |
760 | ||
761 | spin_lock_irqsave(&anchor->lock, flags); | |
762 | if (!list_empty(&anchor->urb_list)) { | |
763 | victim = list_entry(anchor->urb_list.next, struct urb, | |
764 | anchor_list); | |
765 | usb_get_urb(victim); | |
766 | spin_unlock_irqrestore(&anchor->lock, flags); | |
767 | usb_unanchor_urb(victim); | |
768 | } else { | |
769 | spin_unlock_irqrestore(&anchor->lock, flags); | |
770 | victim = NULL; | |
771 | } | |
772 | ||
773 | return victim; | |
774 | } | |
775 | ||
776 | EXPORT_SYMBOL_GPL(usb_get_from_anchor); | |
777 | ||
778 | /** | |
779 | * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs | |
780 | * @anchor: the anchor whose urbs you want to unanchor | |
781 | * | |
782 | * use this to get rid of all an anchor's urbs | |
783 | */ | |
784 | void usb_scuttle_anchored_urbs(struct usb_anchor *anchor) | |
785 | { | |
786 | struct urb *victim; | |
787 | unsigned long flags; | |
788 | ||
789 | spin_lock_irqsave(&anchor->lock, flags); | |
790 | while (!list_empty(&anchor->urb_list)) { | |
791 | victim = list_entry(anchor->urb_list.prev, struct urb, | |
792 | anchor_list); | |
793 | usb_get_urb(victim); | |
794 | spin_unlock_irqrestore(&anchor->lock, flags); | |
795 | /* this may free the URB */ | |
796 | usb_unanchor_urb(victim); | |
797 | usb_put_urb(victim); | |
798 | spin_lock_irqsave(&anchor->lock, flags); | |
799 | } | |
800 | spin_unlock_irqrestore(&anchor->lock, flags); | |
801 | } | |
802 | ||
803 | EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs); | |
804 | ||
805 | /** | |
806 | * usb_anchor_empty - is an anchor empty | |
807 | * @anchor: the anchor you want to query | |
808 | * | |
809 | * returns 1 if the anchor has no urbs associated with it | |
810 | */ | |
811 | int usb_anchor_empty(struct usb_anchor *anchor) | |
812 | { | |
813 | return list_empty(&anchor->urb_list); | |
814 | } | |
815 | ||
816 | EXPORT_SYMBOL_GPL(usb_anchor_empty); | |
817 |