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1da177e4 LT |
1 | #include <linux/config.h> |
2 | #include <linux/module.h> | |
3 | #include <linux/string.h> | |
4 | #include <linux/bitops.h> | |
5 | #include <linux/slab.h> | |
6 | #include <linux/init.h> | |
7 | ||
8 | #ifdef CONFIG_USB_DEBUG | |
9 | #define DEBUG | |
10 | #else | |
11 | #undef DEBUG | |
12 | #endif | |
13 | #include <linux/usb.h> | |
14 | #include "hcd.h" | |
15 | ||
16 | #define to_urb(d) container_of(d, struct urb, kref) | |
17 | ||
18 | static void urb_destroy(struct kref *kref) | |
19 | { | |
20 | struct urb *urb = to_urb(kref); | |
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); | |
43 | spin_lock_init(&urb->lock); | |
44 | } | |
45 | } | |
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 | */ | |
5db539e4 | 63 | struct urb *usb_alloc_urb(int iso_packets, unsigned mem_flags) |
1da177e4 LT |
64 | { |
65 | struct urb *urb; | |
66 | ||
67 | urb = (struct urb *)kmalloc(sizeof(struct urb) + | |
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 | } | |
77 | ||
78 | /** | |
79 | * usb_free_urb - frees the memory used by a urb when all users of it are finished | |
80 | * @urb: pointer to the urb to free, may be NULL | |
81 | * | |
82 | * Must be called when a user of a urb is finished with it. When the last user | |
83 | * of the urb calls this function, the memory of the urb is freed. | |
84 | * | |
85 | * Note: The transfer buffer associated with the urb is not freed, that must be | |
86 | * done elsewhere. | |
87 | */ | |
88 | void usb_free_urb(struct urb *urb) | |
89 | { | |
90 | if (urb) | |
91 | kref_put(&urb->kref, urb_destroy); | |
92 | } | |
93 | ||
94 | /** | |
95 | * usb_get_urb - increments the reference count of the urb | |
96 | * @urb: pointer to the urb to modify, may be NULL | |
97 | * | |
98 | * This must be called whenever a urb is transferred from a device driver to a | |
99 | * host controller driver. This allows proper reference counting to happen | |
100 | * for urbs. | |
101 | * | |
102 | * A pointer to the urb with the incremented reference counter is returned. | |
103 | */ | |
104 | struct urb * usb_get_urb(struct urb *urb) | |
105 | { | |
106 | if (urb) | |
107 | kref_get(&urb->kref); | |
108 | return urb; | |
109 | } | |
110 | ||
111 | ||
112 | /*-------------------------------------------------------------------*/ | |
113 | ||
114 | /** | |
115 | * usb_submit_urb - issue an asynchronous transfer request for an endpoint | |
116 | * @urb: pointer to the urb describing the request | |
117 | * @mem_flags: the type of memory to allocate, see kmalloc() for a list | |
118 | * of valid options for this. | |
119 | * | |
120 | * This submits a transfer request, and transfers control of the URB | |
121 | * describing that request to the USB subsystem. Request completion will | |
122 | * be indicated later, asynchronously, by calling the completion handler. | |
123 | * The three types of completion are success, error, and unlink | |
093cf723 | 124 | * (a software-induced fault, also called "request cancellation"). |
1da177e4 LT |
125 | * |
126 | * URBs may be submitted in interrupt context. | |
127 | * | |
128 | * The caller must have correctly initialized the URB before submitting | |
129 | * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are | |
130 | * available to ensure that most fields are correctly initialized, for | |
131 | * the particular kind of transfer, although they will not initialize | |
132 | * any transfer flags. | |
133 | * | |
134 | * Successful submissions return 0; otherwise this routine returns a | |
135 | * negative error number. If the submission is successful, the complete() | |
136 | * callback from the URB will be called exactly once, when the USB core and | |
137 | * Host Controller Driver (HCD) are finished with the URB. When the completion | |
138 | * function is called, control of the URB is returned to the device | |
139 | * driver which issued the request. The completion handler may then | |
140 | * immediately free or reuse that URB. | |
141 | * | |
142 | * With few exceptions, USB device drivers should never access URB fields | |
143 | * provided by usbcore or the HCD until its complete() is called. | |
144 | * The exceptions relate to periodic transfer scheduling. For both | |
145 | * interrupt and isochronous urbs, as part of successful URB submission | |
146 | * urb->interval is modified to reflect the actual transfer period used | |
147 | * (normally some power of two units). And for isochronous urbs, | |
148 | * urb->start_frame is modified to reflect when the URB's transfers were | |
149 | * scheduled to start. Not all isochronous transfer scheduling policies | |
150 | * will work, but most host controller drivers should easily handle ISO | |
151 | * queues going from now until 10-200 msec into the future. | |
152 | * | |
153 | * For control endpoints, the synchronous usb_control_msg() call is | |
154 | * often used (in non-interrupt context) instead of this call. | |
155 | * That is often used through convenience wrappers, for the requests | |
156 | * that are standardized in the USB 2.0 specification. For bulk | |
157 | * endpoints, a synchronous usb_bulk_msg() call is available. | |
158 | * | |
159 | * Request Queuing: | |
160 | * | |
161 | * URBs may be submitted to endpoints before previous ones complete, to | |
162 | * minimize the impact of interrupt latencies and system overhead on data | |
163 | * throughput. With that queuing policy, an endpoint's queue would never | |
164 | * be empty. This is required for continuous isochronous data streams, | |
165 | * and may also be required for some kinds of interrupt transfers. Such | |
166 | * queuing also maximizes bandwidth utilization by letting USB controllers | |
167 | * start work on later requests before driver software has finished the | |
168 | * completion processing for earlier (successful) requests. | |
169 | * | |
170 | * As of Linux 2.6, all USB endpoint transfer queues support depths greater | |
171 | * than one. This was previously a HCD-specific behavior, except for ISO | |
172 | * transfers. Non-isochronous endpoint queues are inactive during cleanup | |
093cf723 | 173 | * after faults (transfer errors or cancellation). |
1da177e4 LT |
174 | * |
175 | * Reserved Bandwidth Transfers: | |
176 | * | |
177 | * Periodic transfers (interrupt or isochronous) are performed repeatedly, | |
178 | * using the interval specified in the urb. Submitting the first urb to | |
179 | * the endpoint reserves the bandwidth necessary to make those transfers. | |
180 | * If the USB subsystem can't allocate sufficient bandwidth to perform | |
181 | * the periodic request, submitting such a periodic request should fail. | |
182 | * | |
183 | * Device drivers must explicitly request that repetition, by ensuring that | |
184 | * some URB is always on the endpoint's queue (except possibly for short | |
185 | * periods during completion callacks). When there is no longer an urb | |
186 | * queued, the endpoint's bandwidth reservation is canceled. This means | |
187 | * drivers can use their completion handlers to ensure they keep bandwidth | |
188 | * they need, by reinitializing and resubmitting the just-completed urb | |
189 | * until the driver longer needs that periodic bandwidth. | |
190 | * | |
191 | * Memory Flags: | |
192 | * | |
193 | * The general rules for how to decide which mem_flags to use | |
194 | * are the same as for kmalloc. There are four | |
195 | * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and | |
196 | * GFP_ATOMIC. | |
197 | * | |
198 | * GFP_NOFS is not ever used, as it has not been implemented yet. | |
199 | * | |
200 | * GFP_ATOMIC is used when | |
201 | * (a) you are inside a completion handler, an interrupt, bottom half, | |
202 | * tasklet or timer, or | |
203 | * (b) you are holding a spinlock or rwlock (does not apply to | |
204 | * semaphores), or | |
205 | * (c) current->state != TASK_RUNNING, this is the case only after | |
206 | * you've changed it. | |
207 | * | |
208 | * GFP_NOIO is used in the block io path and error handling of storage | |
209 | * devices. | |
210 | * | |
211 | * All other situations use GFP_KERNEL. | |
212 | * | |
213 | * Some more specific rules for mem_flags can be inferred, such as | |
214 | * (1) start_xmit, timeout, and receive methods of network drivers must | |
215 | * use GFP_ATOMIC (they are called with a spinlock held); | |
216 | * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also | |
217 | * called with a spinlock held); | |
218 | * (3) If you use a kernel thread with a network driver you must use | |
219 | * GFP_NOIO, unless (b) or (c) apply; | |
220 | * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c) | |
221 | * apply or your are in a storage driver's block io path; | |
222 | * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and | |
223 | * (6) changing firmware on a running storage or net device uses | |
224 | * GFP_NOIO, unless b) or c) apply | |
225 | * | |
226 | */ | |
5db539e4 | 227 | int usb_submit_urb(struct urb *urb, unsigned mem_flags) |
1da177e4 LT |
228 | { |
229 | int pipe, temp, max; | |
230 | struct usb_device *dev; | |
231 | struct usb_operations *op; | |
232 | int is_out; | |
233 | ||
234 | if (!urb || urb->hcpriv || !urb->complete) | |
235 | return -EINVAL; | |
236 | if (!(dev = urb->dev) || | |
237 | (dev->state < USB_STATE_DEFAULT) || | |
238 | (!dev->bus) || (dev->devnum <= 0)) | |
239 | return -ENODEV; | |
240 | if (dev->state == USB_STATE_SUSPENDED) | |
241 | return -EHOSTUNREACH; | |
242 | if (!(op = dev->bus->op) || !op->submit_urb) | |
243 | return -ENODEV; | |
244 | ||
245 | urb->status = -EINPROGRESS; | |
246 | urb->actual_length = 0; | |
247 | urb->bandwidth = 0; | |
248 | ||
249 | /* Lots of sanity checks, so HCDs can rely on clean data | |
250 | * and don't need to duplicate tests | |
251 | */ | |
252 | pipe = urb->pipe; | |
253 | temp = usb_pipetype (pipe); | |
254 | is_out = usb_pipeout (pipe); | |
255 | ||
256 | if (!usb_pipecontrol (pipe) && dev->state < USB_STATE_CONFIGURED) | |
257 | return -ENODEV; | |
258 | ||
259 | /* FIXME there should be a sharable lock protecting us against | |
260 | * config/altsetting changes and disconnects, kicking in here. | |
261 | * (here == before maxpacket, and eventually endpoint type, | |
262 | * checks get made.) | |
263 | */ | |
264 | ||
265 | max = usb_maxpacket (dev, pipe, is_out); | |
266 | if (max <= 0) { | |
267 | dev_dbg(&dev->dev, | |
268 | "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n", | |
269 | usb_pipeendpoint (pipe), is_out ? "out" : "in", | |
270 | __FUNCTION__, max); | |
271 | return -EMSGSIZE; | |
272 | } | |
273 | ||
274 | /* periodic transfers limit size per frame/uframe, | |
275 | * but drivers only control those sizes for ISO. | |
276 | * while we're checking, initialize return status. | |
277 | */ | |
278 | if (temp == PIPE_ISOCHRONOUS) { | |
279 | int n, len; | |
280 | ||
281 | /* "high bandwidth" mode, 1-3 packets/uframe? */ | |
282 | if (dev->speed == USB_SPEED_HIGH) { | |
283 | int mult = 1 + ((max >> 11) & 0x03); | |
284 | max &= 0x07ff; | |
285 | max *= mult; | |
286 | } | |
287 | ||
288 | if (urb->number_of_packets <= 0) | |
289 | return -EINVAL; | |
290 | for (n = 0; n < urb->number_of_packets; n++) { | |
291 | len = urb->iso_frame_desc [n].length; | |
292 | if (len < 0 || len > max) | |
293 | return -EMSGSIZE; | |
294 | urb->iso_frame_desc [n].status = -EXDEV; | |
295 | urb->iso_frame_desc [n].actual_length = 0; | |
296 | } | |
297 | } | |
298 | ||
299 | /* the I/O buffer must be mapped/unmapped, except when length=0 */ | |
300 | if (urb->transfer_buffer_length < 0) | |
301 | return -EMSGSIZE; | |
302 | ||
303 | #ifdef DEBUG | |
304 | /* stuff that drivers shouldn't do, but which shouldn't | |
305 | * cause problems in HCDs if they get it wrong. | |
306 | */ | |
307 | { | |
308 | unsigned int orig_flags = urb->transfer_flags; | |
309 | unsigned int allowed; | |
310 | ||
311 | /* enforce simple/standard policy */ | |
b375a049 AS |
312 | allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_SETUP_DMA_MAP | |
313 | URB_NO_INTERRUPT); | |
1da177e4 LT |
314 | switch (temp) { |
315 | case PIPE_BULK: | |
316 | if (is_out) | |
317 | allowed |= URB_ZERO_PACKET; | |
318 | /* FALLTHROUGH */ | |
319 | case PIPE_CONTROL: | |
320 | allowed |= URB_NO_FSBR; /* only affects UHCI */ | |
321 | /* FALLTHROUGH */ | |
322 | default: /* all non-iso endpoints */ | |
323 | if (!is_out) | |
324 | allowed |= URB_SHORT_NOT_OK; | |
325 | break; | |
326 | case PIPE_ISOCHRONOUS: | |
327 | allowed |= URB_ISO_ASAP; | |
328 | break; | |
329 | } | |
330 | urb->transfer_flags &= allowed; | |
331 | ||
332 | /* fail if submitter gave bogus flags */ | |
333 | if (urb->transfer_flags != orig_flags) { | |
334 | err ("BOGUS urb flags, %x --> %x", | |
335 | orig_flags, urb->transfer_flags); | |
336 | return -EINVAL; | |
337 | } | |
338 | } | |
339 | #endif | |
340 | /* | |
341 | * Force periodic transfer intervals to be legal values that are | |
342 | * a power of two (so HCDs don't need to). | |
343 | * | |
344 | * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC | |
345 | * supports different values... this uses EHCI/UHCI defaults (and | |
346 | * EHCI can use smaller non-default values). | |
347 | */ | |
348 | switch (temp) { | |
349 | case PIPE_ISOCHRONOUS: | |
350 | case PIPE_INTERRUPT: | |
351 | /* too small? */ | |
352 | if (urb->interval <= 0) | |
353 | return -EINVAL; | |
354 | /* too big? */ | |
355 | switch (dev->speed) { | |
356 | case USB_SPEED_HIGH: /* units are microframes */ | |
357 | // NOTE usb handles 2^15 | |
358 | if (urb->interval > (1024 * 8)) | |
359 | urb->interval = 1024 * 8; | |
360 | temp = 1024 * 8; | |
361 | break; | |
362 | case USB_SPEED_FULL: /* units are frames/msec */ | |
363 | case USB_SPEED_LOW: | |
364 | if (temp == PIPE_INTERRUPT) { | |
365 | if (urb->interval > 255) | |
366 | return -EINVAL; | |
367 | // NOTE ohci only handles up to 32 | |
368 | temp = 128; | |
369 | } else { | |
370 | if (urb->interval > 1024) | |
371 | urb->interval = 1024; | |
372 | // NOTE usb and ohci handle up to 2^15 | |
373 | temp = 1024; | |
374 | } | |
375 | break; | |
376 | default: | |
377 | return -EINVAL; | |
378 | } | |
379 | /* power of two? */ | |
380 | while (temp > urb->interval) | |
381 | temp >>= 1; | |
382 | urb->interval = temp; | |
383 | } | |
384 | ||
385 | return op->submit_urb (urb, mem_flags); | |
386 | } | |
387 | ||
388 | /*-------------------------------------------------------------------*/ | |
389 | ||
390 | /** | |
391 | * usb_unlink_urb - abort/cancel a transfer request for an endpoint | |
392 | * @urb: pointer to urb describing a previously submitted request, | |
393 | * may be NULL | |
394 | * | |
395 | * This routine cancels an in-progress request. URBs complete only | |
396 | * once per submission, and may be canceled only once per submission. | |
093cf723 | 397 | * Successful cancellation means the requests's completion handler will |
1da177e4 LT |
398 | * be called with a status code indicating that the request has been |
399 | * canceled (rather than any other code) and will quickly be removed | |
400 | * from host controller data structures. | |
401 | * | |
b375a049 AS |
402 | * This request is always asynchronous. |
403 | * Success is indicated by returning -EINPROGRESS, | |
1da177e4 LT |
404 | * at which time the URB will normally have been unlinked but not yet |
405 | * given back to the device driver. When it is called, the completion | |
406 | * function will see urb->status == -ECONNRESET. Failure is indicated | |
407 | * by any other return value. Unlinking will fail when the URB is not | |
408 | * currently "linked" (i.e., it was never submitted, or it was unlinked | |
409 | * before, or the hardware is already finished with it), even if the | |
410 | * completion handler has not yet run. | |
411 | * | |
412 | * Unlinking and Endpoint Queues: | |
413 | * | |
414 | * Host Controller Drivers (HCDs) place all the URBs for a particular | |
415 | * endpoint in a queue. Normally the queue advances as the controller | |
8835f665 AS |
416 | * hardware processes each request. But when an URB terminates with an |
417 | * error its queue stops, at least until that URB's completion routine | |
418 | * returns. It is guaranteed that the queue will not restart until all | |
419 | * its unlinked URBs have been fully retired, with their completion | |
420 | * routines run, even if that's not until some time after the original | |
421 | * completion handler returns. Normally the same behavior and guarantees | |
422 | * apply when an URB terminates because it was unlinked; however if an | |
423 | * URB is unlinked before the hardware has started to execute it, then | |
424 | * its queue is not guaranteed to stop until all the preceding URBs have | |
425 | * completed. | |
1da177e4 LT |
426 | * |
427 | * This means that USB device drivers can safely build deep queues for | |
428 | * large or complex transfers, and clean them up reliably after any sort | |
429 | * of aborted transfer by unlinking all pending URBs at the first fault. | |
430 | * | |
431 | * Note that an URB terminating early because a short packet was received | |
432 | * will count as an error if and only if the URB_SHORT_NOT_OK flag is set. | |
433 | * Also, that all unlinks performed in any URB completion handler must | |
434 | * be asynchronous. | |
435 | * | |
436 | * Queues for isochronous endpoints are treated differently, because they | |
437 | * advance at fixed rates. Such queues do not stop when an URB is unlinked. | |
438 | * An unlinked URB may leave a gap in the stream of packets. It is undefined | |
439 | * whether such gaps can be filled in. | |
440 | * | |
441 | * When a control URB terminates with an error, it is likely that the | |
442 | * status stage of the transfer will not take place, even if it is merely | |
443 | * a soft error resulting from a short-packet with URB_SHORT_NOT_OK set. | |
444 | */ | |
445 | int usb_unlink_urb(struct urb *urb) | |
446 | { | |
447 | if (!urb) | |
448 | return -EINVAL; | |
1da177e4 LT |
449 | if (!(urb->dev && urb->dev->bus && urb->dev->bus->op)) |
450 | return -ENODEV; | |
451 | return urb->dev->bus->op->unlink_urb(urb, -ECONNRESET); | |
452 | } | |
453 | ||
454 | /** | |
455 | * usb_kill_urb - cancel a transfer request and wait for it to finish | |
456 | * @urb: pointer to URB describing a previously submitted request, | |
457 | * may be NULL | |
458 | * | |
459 | * This routine cancels an in-progress request. It is guaranteed that | |
460 | * upon return all completion handlers will have finished and the URB | |
461 | * will be totally idle and available for reuse. These features make | |
462 | * this an ideal way to stop I/O in a disconnect() callback or close() | |
463 | * function. If the request has not already finished or been unlinked | |
464 | * the completion handler will see urb->status == -ENOENT. | |
465 | * | |
466 | * While the routine is running, attempts to resubmit the URB will fail | |
467 | * with error -EPERM. Thus even if the URB's completion handler always | |
468 | * tries to resubmit, it will not succeed and the URB will become idle. | |
469 | * | |
470 | * This routine may not be used in an interrupt context (such as a bottom | |
471 | * half or a completion handler), or when holding a spinlock, or in other | |
472 | * situations where the caller can't schedule(). | |
473 | */ | |
474 | void usb_kill_urb(struct urb *urb) | |
475 | { | |
476 | if (!(urb && urb->dev && urb->dev->bus && urb->dev->bus->op)) | |
477 | return; | |
478 | spin_lock_irq(&urb->lock); | |
479 | ++urb->reject; | |
480 | spin_unlock_irq(&urb->lock); | |
481 | ||
482 | urb->dev->bus->op->unlink_urb(urb, -ENOENT); | |
483 | wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); | |
484 | ||
485 | spin_lock_irq(&urb->lock); | |
486 | --urb->reject; | |
487 | spin_unlock_irq(&urb->lock); | |
488 | } | |
489 | ||
490 | EXPORT_SYMBOL(usb_init_urb); | |
491 | EXPORT_SYMBOL(usb_alloc_urb); | |
492 | EXPORT_SYMBOL(usb_free_urb); | |
493 | EXPORT_SYMBOL(usb_get_urb); | |
494 | EXPORT_SYMBOL(usb_submit_urb); | |
495 | EXPORT_SYMBOL(usb_unlink_urb); | |
496 | EXPORT_SYMBOL(usb_kill_urb); | |
497 |