blob: 9801d08edacf8db26056175116d28df45af985ed [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -07006#include <linux/usb.h>
7#include "hcd.h"
8
9#define to_urb(d) container_of(d, struct urb, kref)
10
11static void urb_destroy(struct kref *kref)
12{
13 struct urb *urb = to_urb(kref);
14 kfree(urb);
15}
16
17/**
18 * usb_init_urb - initializes a urb so that it can be used by a USB driver
19 * @urb: pointer to the urb to initialize
20 *
21 * Initializes a urb so that the USB subsystem can use it properly.
22 *
23 * If a urb is created with a call to usb_alloc_urb() it is not
24 * necessary to call this function. Only use this if you allocate the
25 * space for a struct urb on your own. If you call this function, be
26 * careful when freeing the memory for your urb that it is no longer in
27 * use by the USB core.
28 *
29 * Only use this function if you _really_ understand what you are doing.
30 */
31void usb_init_urb(struct urb *urb)
32{
33 if (urb) {
34 memset(urb, 0, sizeof(*urb));
35 kref_init(&urb->kref);
36 spin_lock_init(&urb->lock);
37 }
38}
39
40/**
41 * usb_alloc_urb - creates a new urb for a USB driver to use
42 * @iso_packets: number of iso packets for this urb
43 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
44 * valid options for this.
45 *
46 * Creates an urb for the USB driver to use, initializes a few internal
47 * structures, incrementes the usage counter, and returns a pointer to it.
48 *
49 * If no memory is available, NULL is returned.
50 *
51 * If the driver want to use this urb for interrupt, control, or bulk
52 * endpoints, pass '0' as the number of iso packets.
53 *
54 * The driver must call usb_free_urb() when it is finished with the urb.
55 */
Al Viro55016f12005-10-21 03:21:58 -040056struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -070057{
58 struct urb *urb;
59
Tobias Klauserec17cf12006-09-13 21:38:41 +020060 urb = kmalloc(sizeof(struct urb) +
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 iso_packets * sizeof(struct usb_iso_packet_descriptor),
62 mem_flags);
63 if (!urb) {
64 err("alloc_urb: kmalloc failed");
65 return NULL;
66 }
67 usb_init_urb(urb);
68 return urb;
69}
70
71/**
72 * usb_free_urb - frees the memory used by a urb when all users of it are finished
73 * @urb: pointer to the urb to free, may be NULL
74 *
75 * Must be called when a user of a urb is finished with it. When the last user
76 * of the urb calls this function, the memory of the urb is freed.
77 *
78 * Note: The transfer buffer associated with the urb is not freed, that must be
79 * done elsewhere.
80 */
81void usb_free_urb(struct urb *urb)
82{
83 if (urb)
84 kref_put(&urb->kref, urb_destroy);
85}
86
87/**
88 * usb_get_urb - increments the reference count of the urb
89 * @urb: pointer to the urb to modify, may be NULL
90 *
91 * This must be called whenever a urb is transferred from a device driver to a
92 * host controller driver. This allows proper reference counting to happen
93 * for urbs.
94 *
95 * A pointer to the urb with the incremented reference counter is returned.
96 */
97struct urb * usb_get_urb(struct urb *urb)
98{
99 if (urb)
100 kref_get(&urb->kref);
101 return urb;
102}
103
104
105/*-------------------------------------------------------------------*/
106
107/**
108 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
109 * @urb: pointer to the urb describing the request
110 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
111 * of valid options for this.
112 *
113 * This submits a transfer request, and transfers control of the URB
114 * describing that request to the USB subsystem. Request completion will
115 * be indicated later, asynchronously, by calling the completion handler.
116 * The three types of completion are success, error, and unlink
Steven Cole093cf722005-05-03 19:07:24 -0600117 * (a software-induced fault, also called "request cancellation").
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 *
119 * URBs may be submitted in interrupt context.
120 *
121 * The caller must have correctly initialized the URB before submitting
122 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
123 * available to ensure that most fields are correctly initialized, for
124 * the particular kind of transfer, although they will not initialize
125 * any transfer flags.
126 *
127 * Successful submissions return 0; otherwise this routine returns a
128 * negative error number. If the submission is successful, the complete()
129 * callback from the URB will be called exactly once, when the USB core and
130 * Host Controller Driver (HCD) are finished with the URB. When the completion
131 * function is called, control of the URB is returned to the device
132 * driver which issued the request. The completion handler may then
133 * immediately free or reuse that URB.
134 *
135 * With few exceptions, USB device drivers should never access URB fields
136 * provided by usbcore or the HCD until its complete() is called.
137 * The exceptions relate to periodic transfer scheduling. For both
138 * interrupt and isochronous urbs, as part of successful URB submission
139 * urb->interval is modified to reflect the actual transfer period used
140 * (normally some power of two units). And for isochronous urbs,
141 * urb->start_frame is modified to reflect when the URB's transfers were
142 * scheduled to start. Not all isochronous transfer scheduling policies
143 * will work, but most host controller drivers should easily handle ISO
144 * queues going from now until 10-200 msec into the future.
145 *
146 * For control endpoints, the synchronous usb_control_msg() call is
147 * often used (in non-interrupt context) instead of this call.
148 * That is often used through convenience wrappers, for the requests
149 * that are standardized in the USB 2.0 specification. For bulk
150 * endpoints, a synchronous usb_bulk_msg() call is available.
151 *
152 * Request Queuing:
153 *
154 * URBs may be submitted to endpoints before previous ones complete, to
155 * minimize the impact of interrupt latencies and system overhead on data
156 * throughput. With that queuing policy, an endpoint's queue would never
157 * be empty. This is required for continuous isochronous data streams,
158 * and may also be required for some kinds of interrupt transfers. Such
159 * queuing also maximizes bandwidth utilization by letting USB controllers
160 * start work on later requests before driver software has finished the
161 * completion processing for earlier (successful) requests.
162 *
163 * As of Linux 2.6, all USB endpoint transfer queues support depths greater
164 * than one. This was previously a HCD-specific behavior, except for ISO
165 * transfers. Non-isochronous endpoint queues are inactive during cleanup
Steven Cole093cf722005-05-03 19:07:24 -0600166 * after faults (transfer errors or cancellation).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 *
168 * Reserved Bandwidth Transfers:
169 *
170 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
171 * using the interval specified in the urb. Submitting the first urb to
172 * the endpoint reserves the bandwidth necessary to make those transfers.
173 * If the USB subsystem can't allocate sufficient bandwidth to perform
174 * the periodic request, submitting such a periodic request should fail.
175 *
176 * Device drivers must explicitly request that repetition, by ensuring that
177 * some URB is always on the endpoint's queue (except possibly for short
178 * periods during completion callacks). When there is no longer an urb
179 * queued, the endpoint's bandwidth reservation is canceled. This means
180 * drivers can use their completion handlers to ensure they keep bandwidth
181 * they need, by reinitializing and resubmitting the just-completed urb
182 * until the driver longer needs that periodic bandwidth.
183 *
184 * Memory Flags:
185 *
186 * The general rules for how to decide which mem_flags to use
187 * are the same as for kmalloc. There are four
188 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
189 * GFP_ATOMIC.
190 *
191 * GFP_NOFS is not ever used, as it has not been implemented yet.
192 *
193 * GFP_ATOMIC is used when
194 * (a) you are inside a completion handler, an interrupt, bottom half,
195 * tasklet or timer, or
196 * (b) you are holding a spinlock or rwlock (does not apply to
197 * semaphores), or
198 * (c) current->state != TASK_RUNNING, this is the case only after
199 * you've changed it.
200 *
201 * GFP_NOIO is used in the block io path and error handling of storage
202 * devices.
203 *
204 * All other situations use GFP_KERNEL.
205 *
206 * Some more specific rules for mem_flags can be inferred, such as
207 * (1) start_xmit, timeout, and receive methods of network drivers must
208 * use GFP_ATOMIC (they are called with a spinlock held);
209 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
210 * called with a spinlock held);
211 * (3) If you use a kernel thread with a network driver you must use
212 * GFP_NOIO, unless (b) or (c) apply;
213 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
214 * apply or your are in a storage driver's block io path;
215 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
216 * (6) changing firmware on a running storage or net device uses
217 * GFP_NOIO, unless b) or c) apply
218 *
219 */
Al Viro55016f12005-10-21 03:21:58 -0400220int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221{
222 int pipe, temp, max;
223 struct usb_device *dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 int is_out;
225
226 if (!urb || urb->hcpriv || !urb->complete)
227 return -EINVAL;
228 if (!(dev = urb->dev) ||
229 (dev->state < USB_STATE_DEFAULT) ||
230 (!dev->bus) || (dev->devnum <= 0))
231 return -ENODEV;
David Brownellb13296c2005-09-27 10:38:54 -0700232 if (dev->bus->controller->power.power_state.event != PM_EVENT_ON
233 || dev->state == USB_STATE_SUSPENDED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 return -EHOSTUNREACH;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
236 urb->status = -EINPROGRESS;
237 urb->actual_length = 0;
238 urb->bandwidth = 0;
239
240 /* Lots of sanity checks, so HCDs can rely on clean data
241 * and don't need to duplicate tests
242 */
243 pipe = urb->pipe;
244 temp = usb_pipetype (pipe);
245 is_out = usb_pipeout (pipe);
246
247 if (!usb_pipecontrol (pipe) && dev->state < USB_STATE_CONFIGURED)
248 return -ENODEV;
249
250 /* FIXME there should be a sharable lock protecting us against
251 * config/altsetting changes and disconnects, kicking in here.
252 * (here == before maxpacket, and eventually endpoint type,
253 * checks get made.)
254 */
255
256 max = usb_maxpacket (dev, pipe, is_out);
257 if (max <= 0) {
258 dev_dbg(&dev->dev,
259 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
260 usb_pipeendpoint (pipe), is_out ? "out" : "in",
261 __FUNCTION__, max);
262 return -EMSGSIZE;
263 }
264
265 /* periodic transfers limit size per frame/uframe,
266 * but drivers only control those sizes for ISO.
267 * while we're checking, initialize return status.
268 */
269 if (temp == PIPE_ISOCHRONOUS) {
270 int n, len;
271
272 /* "high bandwidth" mode, 1-3 packets/uframe? */
273 if (dev->speed == USB_SPEED_HIGH) {
274 int mult = 1 + ((max >> 11) & 0x03);
275 max &= 0x07ff;
276 max *= mult;
277 }
278
279 if (urb->number_of_packets <= 0)
280 return -EINVAL;
281 for (n = 0; n < urb->number_of_packets; n++) {
282 len = urb->iso_frame_desc [n].length;
283 if (len < 0 || len > max)
284 return -EMSGSIZE;
285 urb->iso_frame_desc [n].status = -EXDEV;
286 urb->iso_frame_desc [n].actual_length = 0;
287 }
288 }
289
290 /* the I/O buffer must be mapped/unmapped, except when length=0 */
291 if (urb->transfer_buffer_length < 0)
292 return -EMSGSIZE;
293
294#ifdef DEBUG
295 /* stuff that drivers shouldn't do, but which shouldn't
296 * cause problems in HCDs if they get it wrong.
297 */
298 {
299 unsigned int orig_flags = urb->transfer_flags;
300 unsigned int allowed;
301
302 /* enforce simple/standard policy */
Alan Sternb375a042005-07-29 16:11:07 -0400303 allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_SETUP_DMA_MAP |
304 URB_NO_INTERRUPT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 switch (temp) {
306 case PIPE_BULK:
307 if (is_out)
308 allowed |= URB_ZERO_PACKET;
309 /* FALLTHROUGH */
310 case PIPE_CONTROL:
311 allowed |= URB_NO_FSBR; /* only affects UHCI */
312 /* FALLTHROUGH */
313 default: /* all non-iso endpoints */
314 if (!is_out)
315 allowed |= URB_SHORT_NOT_OK;
316 break;
317 case PIPE_ISOCHRONOUS:
318 allowed |= URB_ISO_ASAP;
319 break;
320 }
321 urb->transfer_flags &= allowed;
322
323 /* fail if submitter gave bogus flags */
324 if (urb->transfer_flags != orig_flags) {
325 err ("BOGUS urb flags, %x --> %x",
326 orig_flags, urb->transfer_flags);
327 return -EINVAL;
328 }
329 }
330#endif
331 /*
332 * Force periodic transfer intervals to be legal values that are
333 * a power of two (so HCDs don't need to).
334 *
335 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
336 * supports different values... this uses EHCI/UHCI defaults (and
337 * EHCI can use smaller non-default values).
338 */
339 switch (temp) {
340 case PIPE_ISOCHRONOUS:
341 case PIPE_INTERRUPT:
342 /* too small? */
343 if (urb->interval <= 0)
344 return -EINVAL;
345 /* too big? */
346 switch (dev->speed) {
347 case USB_SPEED_HIGH: /* units are microframes */
348 // NOTE usb handles 2^15
349 if (urb->interval > (1024 * 8))
350 urb->interval = 1024 * 8;
351 temp = 1024 * 8;
352 break;
353 case USB_SPEED_FULL: /* units are frames/msec */
354 case USB_SPEED_LOW:
355 if (temp == PIPE_INTERRUPT) {
356 if (urb->interval > 255)
357 return -EINVAL;
358 // NOTE ohci only handles up to 32
359 temp = 128;
360 } else {
361 if (urb->interval > 1024)
362 urb->interval = 1024;
363 // NOTE usb and ohci handle up to 2^15
364 temp = 1024;
365 }
366 break;
367 default:
368 return -EINVAL;
369 }
370 /* power of two? */
371 while (temp > urb->interval)
372 temp >>= 1;
373 urb->interval = temp;
374 }
375
Alan Sterna6d2bb92006-08-30 11:27:36 -0400376 return usb_hcd_submit_urb (urb, mem_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377}
378
379/*-------------------------------------------------------------------*/
380
381/**
382 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
383 * @urb: pointer to urb describing a previously submitted request,
384 * may be NULL
385 *
386 * This routine cancels an in-progress request. URBs complete only
387 * once per submission, and may be canceled only once per submission.
Steven Cole093cf722005-05-03 19:07:24 -0600388 * Successful cancellation means the requests's completion handler will
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 * be called with a status code indicating that the request has been
390 * canceled (rather than any other code) and will quickly be removed
391 * from host controller data structures.
392 *
Alan Sternb375a042005-07-29 16:11:07 -0400393 * This request is always asynchronous.
394 * Success is indicated by returning -EINPROGRESS,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 * at which time the URB will normally have been unlinked but not yet
396 * given back to the device driver. When it is called, the completion
397 * function will see urb->status == -ECONNRESET. Failure is indicated
398 * by any other return value. Unlinking will fail when the URB is not
399 * currently "linked" (i.e., it was never submitted, or it was unlinked
400 * before, or the hardware is already finished with it), even if the
401 * completion handler has not yet run.
402 *
403 * Unlinking and Endpoint Queues:
404 *
405 * Host Controller Drivers (HCDs) place all the URBs for a particular
406 * endpoint in a queue. Normally the queue advances as the controller
Alan Stern8835f662005-04-18 17:39:30 -0700407 * hardware processes each request. But when an URB terminates with an
408 * error its queue stops, at least until that URB's completion routine
409 * returns. It is guaranteed that the queue will not restart until all
410 * its unlinked URBs have been fully retired, with their completion
411 * routines run, even if that's not until some time after the original
412 * completion handler returns. Normally the same behavior and guarantees
413 * apply when an URB terminates because it was unlinked; however if an
414 * URB is unlinked before the hardware has started to execute it, then
415 * its queue is not guaranteed to stop until all the preceding URBs have
416 * completed.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 *
418 * This means that USB device drivers can safely build deep queues for
419 * large or complex transfers, and clean them up reliably after any sort
420 * of aborted transfer by unlinking all pending URBs at the first fault.
421 *
422 * Note that an URB terminating early because a short packet was received
423 * will count as an error if and only if the URB_SHORT_NOT_OK flag is set.
424 * Also, that all unlinks performed in any URB completion handler must
425 * be asynchronous.
426 *
427 * Queues for isochronous endpoints are treated differently, because they
428 * advance at fixed rates. Such queues do not stop when an URB is unlinked.
429 * An unlinked URB may leave a gap in the stream of packets. It is undefined
430 * whether such gaps can be filled in.
431 *
432 * When a control URB terminates with an error, it is likely that the
433 * status stage of the transfer will not take place, even if it is merely
434 * a soft error resulting from a short-packet with URB_SHORT_NOT_OK set.
435 */
436int usb_unlink_urb(struct urb *urb)
437{
438 if (!urb)
439 return -EINVAL;
Alan Sterna6d2bb92006-08-30 11:27:36 -0400440 if (!(urb->dev && urb->dev->bus))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 return -ENODEV;
Alan Sterna6d2bb92006-08-30 11:27:36 -0400442 return usb_hcd_unlink_urb(urb, -ECONNRESET);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443}
444
445/**
446 * usb_kill_urb - cancel a transfer request and wait for it to finish
447 * @urb: pointer to URB describing a previously submitted request,
448 * may be NULL
449 *
450 * This routine cancels an in-progress request. It is guaranteed that
451 * upon return all completion handlers will have finished and the URB
452 * will be totally idle and available for reuse. These features make
453 * this an ideal way to stop I/O in a disconnect() callback or close()
454 * function. If the request has not already finished or been unlinked
455 * the completion handler will see urb->status == -ENOENT.
456 *
457 * While the routine is running, attempts to resubmit the URB will fail
458 * with error -EPERM. Thus even if the URB's completion handler always
459 * tries to resubmit, it will not succeed and the URB will become idle.
460 *
461 * This routine may not be used in an interrupt context (such as a bottom
462 * half or a completion handler), or when holding a spinlock, or in other
463 * situations where the caller can't schedule().
464 */
465void usb_kill_urb(struct urb *urb)
466{
Greg Kroah-Hartmane9aa7952006-01-23 17:17:21 -0500467 might_sleep();
Alan Sterna6d2bb92006-08-30 11:27:36 -0400468 if (!(urb && urb->dev && urb->dev->bus))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 return;
470 spin_lock_irq(&urb->lock);
471 ++urb->reject;
472 spin_unlock_irq(&urb->lock);
473
Alan Sterna6d2bb92006-08-30 11:27:36 -0400474 usb_hcd_unlink_urb(urb, -ENOENT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
476
477 spin_lock_irq(&urb->lock);
478 --urb->reject;
479 spin_unlock_irq(&urb->lock);
480}
481
482EXPORT_SYMBOL(usb_init_urb);
483EXPORT_SYMBOL(usb_alloc_urb);
484EXPORT_SYMBOL(usb_free_urb);
485EXPORT_SYMBOL(usb_get_urb);
486EXPORT_SYMBOL(usb_submit_urb);
487EXPORT_SYMBOL(usb_unlink_urb);
488EXPORT_SYMBOL(usb_kill_urb);
489