Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6 | #include <linux/usb.h> |
Oliver Neukum | 51a2f07 | 2007-05-25 13:40:56 +0200 | [diff] [blame] | 7 | #include <linux/wait.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | #include "hcd.h" |
| 9 | |
| 10 | #define to_urb(d) container_of(d, struct urb, kref) |
| 11 | |
| 12 | static void urb_destroy(struct kref *kref) |
| 13 | { |
| 14 | struct urb *urb = to_urb(kref); |
Oliver Neukum | 51a2f07 | 2007-05-25 13:40:56 +0200 | [diff] [blame] | 15 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | kfree(urb); |
| 17 | } |
| 18 | |
| 19 | /** |
| 20 | * usb_init_urb - initializes a urb so that it can be used by a USB driver |
| 21 | * @urb: pointer to the urb to initialize |
| 22 | * |
| 23 | * Initializes a urb so that the USB subsystem can use it properly. |
| 24 | * |
| 25 | * If a urb is created with a call to usb_alloc_urb() it is not |
| 26 | * necessary to call this function. Only use this if you allocate the |
| 27 | * space for a struct urb on your own. If you call this function, be |
| 28 | * careful when freeing the memory for your urb that it is no longer in |
| 29 | * use by the USB core. |
| 30 | * |
| 31 | * Only use this function if you _really_ understand what you are doing. |
| 32 | */ |
| 33 | void usb_init_urb(struct urb *urb) |
| 34 | { |
| 35 | if (urb) { |
| 36 | memset(urb, 0, sizeof(*urb)); |
| 37 | kref_init(&urb->kref); |
| 38 | spin_lock_init(&urb->lock); |
Oliver Neukum | 51a2f07 | 2007-05-25 13:40:56 +0200 | [diff] [blame] | 39 | INIT_LIST_HEAD(&urb->anchor_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | } |
| 41 | } |
| 42 | |
| 43 | /** |
| 44 | * usb_alloc_urb - creates a new urb for a USB driver to use |
| 45 | * @iso_packets: number of iso packets for this urb |
| 46 | * @mem_flags: the type of memory to allocate, see kmalloc() for a list of |
| 47 | * valid options for this. |
| 48 | * |
| 49 | * Creates an urb for the USB driver to use, initializes a few internal |
| 50 | * structures, incrementes the usage counter, and returns a pointer to it. |
| 51 | * |
| 52 | * If no memory is available, NULL is returned. |
| 53 | * |
| 54 | * If the driver want to use this urb for interrupt, control, or bulk |
| 55 | * endpoints, pass '0' as the number of iso packets. |
| 56 | * |
| 57 | * The driver must call usb_free_urb() when it is finished with the urb. |
| 58 | */ |
Al Viro | 55016f1 | 2005-10-21 03:21:58 -0400 | [diff] [blame] | 59 | struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | { |
| 61 | struct urb *urb; |
| 62 | |
Tobias Klauser | ec17cf1 | 2006-09-13 21:38:41 +0200 | [diff] [blame] | 63 | urb = kmalloc(sizeof(struct urb) + |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | iso_packets * sizeof(struct usb_iso_packet_descriptor), |
| 65 | mem_flags); |
| 66 | if (!urb) { |
| 67 | err("alloc_urb: kmalloc failed"); |
| 68 | return NULL; |
| 69 | } |
| 70 | usb_init_urb(urb); |
| 71 | return urb; |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * usb_free_urb - frees the memory used by a urb when all users of it are finished |
| 76 | * @urb: pointer to the urb to free, may be NULL |
| 77 | * |
| 78 | * Must be called when a user of a urb is finished with it. When the last user |
| 79 | * of the urb calls this function, the memory of the urb is freed. |
| 80 | * |
| 81 | * Note: The transfer buffer associated with the urb is not freed, that must be |
| 82 | * done elsewhere. |
| 83 | */ |
| 84 | void usb_free_urb(struct urb *urb) |
| 85 | { |
| 86 | if (urb) |
| 87 | kref_put(&urb->kref, urb_destroy); |
| 88 | } |
| 89 | |
| 90 | /** |
| 91 | * usb_get_urb - increments the reference count of the urb |
| 92 | * @urb: pointer to the urb to modify, may be NULL |
| 93 | * |
| 94 | * This must be called whenever a urb is transferred from a device driver to a |
| 95 | * host controller driver. This allows proper reference counting to happen |
| 96 | * for urbs. |
| 97 | * |
| 98 | * A pointer to the urb with the incremented reference counter is returned. |
| 99 | */ |
| 100 | struct urb * usb_get_urb(struct urb *urb) |
| 101 | { |
| 102 | if (urb) |
| 103 | kref_get(&urb->kref); |
| 104 | return urb; |
| 105 | } |
Oliver Neukum | 51a2f07 | 2007-05-25 13:40:56 +0200 | [diff] [blame] | 106 | |
| 107 | /** |
| 108 | * usb_anchor_urb - anchors an URB while it is processed |
| 109 | * @urb: pointer to the urb to anchor |
| 110 | * @anchor: pointer to the anchor |
| 111 | * |
| 112 | * This can be called to have access to URBs which are to be executed |
| 113 | * without bothering to track them |
| 114 | */ |
| 115 | void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor) |
| 116 | { |
| 117 | unsigned long flags; |
| 118 | |
| 119 | spin_lock_irqsave(&anchor->lock, flags); |
| 120 | usb_get_urb(urb); |
| 121 | list_add_tail(&urb->anchor_list, &anchor->urb_list); |
| 122 | urb->anchor = anchor; |
| 123 | spin_unlock_irqrestore(&anchor->lock, flags); |
| 124 | } |
| 125 | EXPORT_SYMBOL_GPL(usb_anchor_urb); |
| 126 | |
| 127 | /** |
| 128 | * usb_unanchor_urb - unanchors an URB |
| 129 | * @urb: pointer to the urb to anchor |
| 130 | * |
| 131 | * Call this to stop the system keeping track of this URB |
| 132 | */ |
| 133 | void usb_unanchor_urb(struct urb *urb) |
| 134 | { |
| 135 | unsigned long flags; |
| 136 | struct usb_anchor *anchor; |
| 137 | |
| 138 | if (!urb) |
| 139 | return; |
| 140 | |
| 141 | anchor = urb->anchor; |
| 142 | if (!anchor) |
| 143 | return; |
| 144 | |
| 145 | spin_lock_irqsave(&anchor->lock, flags); |
| 146 | if (unlikely(anchor != urb->anchor)) { |
| 147 | /* we've lost the race to another thread */ |
| 148 | spin_unlock_irqrestore(&anchor->lock, flags); |
| 149 | return; |
| 150 | } |
| 151 | urb->anchor = NULL; |
| 152 | list_del(&urb->anchor_list); |
| 153 | spin_unlock_irqrestore(&anchor->lock, flags); |
| 154 | usb_put_urb(urb); |
| 155 | if (list_empty(&anchor->urb_list)) |
| 156 | wake_up(&anchor->wait); |
| 157 | } |
| 158 | EXPORT_SYMBOL_GPL(usb_unanchor_urb); |
| 159 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | /*-------------------------------------------------------------------*/ |
| 161 | |
| 162 | /** |
| 163 | * usb_submit_urb - issue an asynchronous transfer request for an endpoint |
| 164 | * @urb: pointer to the urb describing the request |
| 165 | * @mem_flags: the type of memory to allocate, see kmalloc() for a list |
| 166 | * of valid options for this. |
| 167 | * |
| 168 | * This submits a transfer request, and transfers control of the URB |
| 169 | * describing that request to the USB subsystem. Request completion will |
| 170 | * be indicated later, asynchronously, by calling the completion handler. |
| 171 | * The three types of completion are success, error, and unlink |
Steven Cole | 093cf72 | 2005-05-03 19:07:24 -0600 | [diff] [blame] | 172 | * (a software-induced fault, also called "request cancellation"). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | * |
| 174 | * URBs may be submitted in interrupt context. |
| 175 | * |
| 176 | * The caller must have correctly initialized the URB before submitting |
| 177 | * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are |
| 178 | * available to ensure that most fields are correctly initialized, for |
| 179 | * the particular kind of transfer, although they will not initialize |
| 180 | * any transfer flags. |
| 181 | * |
| 182 | * Successful submissions return 0; otherwise this routine returns a |
| 183 | * negative error number. If the submission is successful, the complete() |
| 184 | * callback from the URB will be called exactly once, when the USB core and |
| 185 | * Host Controller Driver (HCD) are finished with the URB. When the completion |
| 186 | * function is called, control of the URB is returned to the device |
| 187 | * driver which issued the request. The completion handler may then |
| 188 | * immediately free or reuse that URB. |
| 189 | * |
| 190 | * With few exceptions, USB device drivers should never access URB fields |
| 191 | * provided by usbcore or the HCD until its complete() is called. |
| 192 | * The exceptions relate to periodic transfer scheduling. For both |
| 193 | * interrupt and isochronous urbs, as part of successful URB submission |
| 194 | * urb->interval is modified to reflect the actual transfer period used |
| 195 | * (normally some power of two units). And for isochronous urbs, |
| 196 | * urb->start_frame is modified to reflect when the URB's transfers were |
| 197 | * scheduled to start. Not all isochronous transfer scheduling policies |
| 198 | * will work, but most host controller drivers should easily handle ISO |
| 199 | * queues going from now until 10-200 msec into the future. |
| 200 | * |
| 201 | * For control endpoints, the synchronous usb_control_msg() call is |
| 202 | * often used (in non-interrupt context) instead of this call. |
| 203 | * That is often used through convenience wrappers, for the requests |
| 204 | * that are standardized in the USB 2.0 specification. For bulk |
| 205 | * endpoints, a synchronous usb_bulk_msg() call is available. |
| 206 | * |
| 207 | * Request Queuing: |
| 208 | * |
| 209 | * URBs may be submitted to endpoints before previous ones complete, to |
| 210 | * minimize the impact of interrupt latencies and system overhead on data |
| 211 | * throughput. With that queuing policy, an endpoint's queue would never |
| 212 | * be empty. This is required for continuous isochronous data streams, |
| 213 | * and may also be required for some kinds of interrupt transfers. Such |
| 214 | * queuing also maximizes bandwidth utilization by letting USB controllers |
| 215 | * start work on later requests before driver software has finished the |
| 216 | * completion processing for earlier (successful) requests. |
| 217 | * |
| 218 | * As of Linux 2.6, all USB endpoint transfer queues support depths greater |
| 219 | * than one. This was previously a HCD-specific behavior, except for ISO |
| 220 | * transfers. Non-isochronous endpoint queues are inactive during cleanup |
Steven Cole | 093cf72 | 2005-05-03 19:07:24 -0600 | [diff] [blame] | 221 | * after faults (transfer errors or cancellation). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | * |
| 223 | * Reserved Bandwidth Transfers: |
| 224 | * |
| 225 | * Periodic transfers (interrupt or isochronous) are performed repeatedly, |
| 226 | * using the interval specified in the urb. Submitting the first urb to |
| 227 | * the endpoint reserves the bandwidth necessary to make those transfers. |
| 228 | * If the USB subsystem can't allocate sufficient bandwidth to perform |
| 229 | * the periodic request, submitting such a periodic request should fail. |
| 230 | * |
| 231 | * Device drivers must explicitly request that repetition, by ensuring that |
| 232 | * some URB is always on the endpoint's queue (except possibly for short |
| 233 | * periods during completion callacks). When there is no longer an urb |
| 234 | * queued, the endpoint's bandwidth reservation is canceled. This means |
| 235 | * drivers can use their completion handlers to ensure they keep bandwidth |
| 236 | * they need, by reinitializing and resubmitting the just-completed urb |
| 237 | * until the driver longer needs that periodic bandwidth. |
| 238 | * |
| 239 | * Memory Flags: |
| 240 | * |
| 241 | * The general rules for how to decide which mem_flags to use |
| 242 | * are the same as for kmalloc. There are four |
| 243 | * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and |
| 244 | * GFP_ATOMIC. |
| 245 | * |
| 246 | * GFP_NOFS is not ever used, as it has not been implemented yet. |
| 247 | * |
| 248 | * GFP_ATOMIC is used when |
| 249 | * (a) you are inside a completion handler, an interrupt, bottom half, |
| 250 | * tasklet or timer, or |
| 251 | * (b) you are holding a spinlock or rwlock (does not apply to |
| 252 | * semaphores), or |
| 253 | * (c) current->state != TASK_RUNNING, this is the case only after |
| 254 | * you've changed it. |
| 255 | * |
| 256 | * GFP_NOIO is used in the block io path and error handling of storage |
| 257 | * devices. |
| 258 | * |
| 259 | * All other situations use GFP_KERNEL. |
| 260 | * |
| 261 | * Some more specific rules for mem_flags can be inferred, such as |
| 262 | * (1) start_xmit, timeout, and receive methods of network drivers must |
| 263 | * use GFP_ATOMIC (they are called with a spinlock held); |
| 264 | * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also |
| 265 | * called with a spinlock held); |
| 266 | * (3) If you use a kernel thread with a network driver you must use |
| 267 | * GFP_NOIO, unless (b) or (c) apply; |
| 268 | * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c) |
| 269 | * apply or your are in a storage driver's block io path; |
| 270 | * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and |
| 271 | * (6) changing firmware on a running storage or net device uses |
| 272 | * GFP_NOIO, unless b) or c) apply |
| 273 | * |
| 274 | */ |
Al Viro | 55016f1 | 2005-10-21 03:21:58 -0400 | [diff] [blame] | 275 | int usb_submit_urb(struct urb *urb, gfp_t mem_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | { |
| 277 | int pipe, temp, max; |
| 278 | struct usb_device *dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | int is_out; |
| 280 | |
| 281 | if (!urb || urb->hcpriv || !urb->complete) |
| 282 | return -EINVAL; |
| 283 | if (!(dev = urb->dev) || |
| 284 | (dev->state < USB_STATE_DEFAULT) || |
| 285 | (!dev->bus) || (dev->devnum <= 0)) |
| 286 | return -ENODEV; |
David Brownell | b13296c | 2005-09-27 10:38:54 -0700 | [diff] [blame] | 287 | if (dev->bus->controller->power.power_state.event != PM_EVENT_ON |
| 288 | || dev->state == USB_STATE_SUSPENDED) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 289 | return -EHOSTUNREACH; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | |
| 291 | urb->status = -EINPROGRESS; |
| 292 | urb->actual_length = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 293 | |
| 294 | /* Lots of sanity checks, so HCDs can rely on clean data |
| 295 | * and don't need to duplicate tests |
| 296 | */ |
| 297 | pipe = urb->pipe; |
Oliver Neukum | 9251644 | 2007-01-23 15:55:28 -0500 | [diff] [blame] | 298 | temp = usb_pipetype(pipe); |
| 299 | is_out = usb_pipeout(pipe); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 300 | |
Oliver Neukum | 9251644 | 2007-01-23 15:55:28 -0500 | [diff] [blame] | 301 | if (!usb_pipecontrol(pipe) && dev->state < USB_STATE_CONFIGURED) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 302 | return -ENODEV; |
| 303 | |
| 304 | /* FIXME there should be a sharable lock protecting us against |
| 305 | * config/altsetting changes and disconnects, kicking in here. |
| 306 | * (here == before maxpacket, and eventually endpoint type, |
| 307 | * checks get made.) |
| 308 | */ |
| 309 | |
Oliver Neukum | 9251644 | 2007-01-23 15:55:28 -0500 | [diff] [blame] | 310 | max = usb_maxpacket(dev, pipe, is_out); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 311 | if (max <= 0) { |
| 312 | dev_dbg(&dev->dev, |
| 313 | "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n", |
Oliver Neukum | 9251644 | 2007-01-23 15:55:28 -0500 | [diff] [blame] | 314 | usb_pipeendpoint(pipe), is_out ? "out" : "in", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 315 | __FUNCTION__, max); |
| 316 | return -EMSGSIZE; |
| 317 | } |
| 318 | |
| 319 | /* periodic transfers limit size per frame/uframe, |
| 320 | * but drivers only control those sizes for ISO. |
| 321 | * while we're checking, initialize return status. |
| 322 | */ |
| 323 | if (temp == PIPE_ISOCHRONOUS) { |
| 324 | int n, len; |
| 325 | |
| 326 | /* "high bandwidth" mode, 1-3 packets/uframe? */ |
| 327 | if (dev->speed == USB_SPEED_HIGH) { |
| 328 | int mult = 1 + ((max >> 11) & 0x03); |
| 329 | max &= 0x07ff; |
| 330 | max *= mult; |
| 331 | } |
| 332 | |
| 333 | if (urb->number_of_packets <= 0) |
| 334 | return -EINVAL; |
| 335 | for (n = 0; n < urb->number_of_packets; n++) { |
Oliver Neukum | 9251644 | 2007-01-23 15:55:28 -0500 | [diff] [blame] | 336 | len = urb->iso_frame_desc[n].length; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 | if (len < 0 || len > max) |
| 338 | return -EMSGSIZE; |
Oliver Neukum | 9251644 | 2007-01-23 15:55:28 -0500 | [diff] [blame] | 339 | urb->iso_frame_desc[n].status = -EXDEV; |
| 340 | urb->iso_frame_desc[n].actual_length = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 341 | } |
| 342 | } |
| 343 | |
| 344 | /* the I/O buffer must be mapped/unmapped, except when length=0 */ |
| 345 | if (urb->transfer_buffer_length < 0) |
| 346 | return -EMSGSIZE; |
| 347 | |
| 348 | #ifdef DEBUG |
| 349 | /* stuff that drivers shouldn't do, but which shouldn't |
| 350 | * cause problems in HCDs if they get it wrong. |
| 351 | */ |
| 352 | { |
| 353 | unsigned int orig_flags = urb->transfer_flags; |
| 354 | unsigned int allowed; |
| 355 | |
| 356 | /* enforce simple/standard policy */ |
Alan Stern | b375a04 | 2005-07-29 16:11:07 -0400 | [diff] [blame] | 357 | allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_SETUP_DMA_MAP | |
| 358 | URB_NO_INTERRUPT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | switch (temp) { |
| 360 | case PIPE_BULK: |
| 361 | if (is_out) |
| 362 | allowed |= URB_ZERO_PACKET; |
| 363 | /* FALLTHROUGH */ |
| 364 | case PIPE_CONTROL: |
| 365 | allowed |= URB_NO_FSBR; /* only affects UHCI */ |
| 366 | /* FALLTHROUGH */ |
| 367 | default: /* all non-iso endpoints */ |
| 368 | if (!is_out) |
| 369 | allowed |= URB_SHORT_NOT_OK; |
| 370 | break; |
| 371 | case PIPE_ISOCHRONOUS: |
| 372 | allowed |= URB_ISO_ASAP; |
| 373 | break; |
| 374 | } |
| 375 | urb->transfer_flags &= allowed; |
| 376 | |
| 377 | /* fail if submitter gave bogus flags */ |
| 378 | if (urb->transfer_flags != orig_flags) { |
Oliver Neukum | 9251644 | 2007-01-23 15:55:28 -0500 | [diff] [blame] | 379 | err("BOGUS urb flags, %x --> %x", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 380 | orig_flags, urb->transfer_flags); |
| 381 | return -EINVAL; |
| 382 | } |
| 383 | } |
| 384 | #endif |
| 385 | /* |
| 386 | * Force periodic transfer intervals to be legal values that are |
| 387 | * a power of two (so HCDs don't need to). |
| 388 | * |
| 389 | * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC |
| 390 | * supports different values... this uses EHCI/UHCI defaults (and |
| 391 | * EHCI can use smaller non-default values). |
| 392 | */ |
| 393 | switch (temp) { |
| 394 | case PIPE_ISOCHRONOUS: |
| 395 | case PIPE_INTERRUPT: |
| 396 | /* too small? */ |
| 397 | if (urb->interval <= 0) |
| 398 | return -EINVAL; |
| 399 | /* too big? */ |
| 400 | switch (dev->speed) { |
| 401 | case USB_SPEED_HIGH: /* units are microframes */ |
| 402 | // NOTE usb handles 2^15 |
| 403 | if (urb->interval > (1024 * 8)) |
| 404 | urb->interval = 1024 * 8; |
| 405 | temp = 1024 * 8; |
| 406 | break; |
| 407 | case USB_SPEED_FULL: /* units are frames/msec */ |
| 408 | case USB_SPEED_LOW: |
| 409 | if (temp == PIPE_INTERRUPT) { |
| 410 | if (urb->interval > 255) |
| 411 | return -EINVAL; |
| 412 | // NOTE ohci only handles up to 32 |
| 413 | temp = 128; |
| 414 | } else { |
| 415 | if (urb->interval > 1024) |
| 416 | urb->interval = 1024; |
| 417 | // NOTE usb and ohci handle up to 2^15 |
| 418 | temp = 1024; |
| 419 | } |
| 420 | break; |
| 421 | default: |
| 422 | return -EINVAL; |
| 423 | } |
| 424 | /* power of two? */ |
| 425 | while (temp > urb->interval) |
| 426 | temp >>= 1; |
| 427 | urb->interval = temp; |
| 428 | } |
| 429 | |
Oliver Neukum | 9251644 | 2007-01-23 15:55:28 -0500 | [diff] [blame] | 430 | return usb_hcd_submit_urb(urb, mem_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | } |
| 432 | |
| 433 | /*-------------------------------------------------------------------*/ |
| 434 | |
| 435 | /** |
| 436 | * usb_unlink_urb - abort/cancel a transfer request for an endpoint |
| 437 | * @urb: pointer to urb describing a previously submitted request, |
| 438 | * may be NULL |
| 439 | * |
| 440 | * This routine cancels an in-progress request. URBs complete only |
| 441 | * once per submission, and may be canceled only once per submission. |
Steven Cole | 093cf72 | 2005-05-03 19:07:24 -0600 | [diff] [blame] | 442 | * Successful cancellation means the requests's completion handler will |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 443 | * be called with a status code indicating that the request has been |
| 444 | * canceled (rather than any other code) and will quickly be removed |
| 445 | * from host controller data structures. |
| 446 | * |
Alan Stern | b375a04 | 2005-07-29 16:11:07 -0400 | [diff] [blame] | 447 | * This request is always asynchronous. |
| 448 | * Success is indicated by returning -EINPROGRESS, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 449 | * at which time the URB will normally have been unlinked but not yet |
| 450 | * given back to the device driver. When it is called, the completion |
| 451 | * function will see urb->status == -ECONNRESET. Failure is indicated |
| 452 | * by any other return value. Unlinking will fail when the URB is not |
| 453 | * currently "linked" (i.e., it was never submitted, or it was unlinked |
| 454 | * before, or the hardware is already finished with it), even if the |
| 455 | * completion handler has not yet run. |
| 456 | * |
| 457 | * Unlinking and Endpoint Queues: |
| 458 | * |
| 459 | * Host Controller Drivers (HCDs) place all the URBs for a particular |
| 460 | * endpoint in a queue. Normally the queue advances as the controller |
Alan Stern | 8835f66 | 2005-04-18 17:39:30 -0700 | [diff] [blame] | 461 | * hardware processes each request. But when an URB terminates with an |
| 462 | * error its queue stops, at least until that URB's completion routine |
| 463 | * returns. It is guaranteed that the queue will not restart until all |
| 464 | * its unlinked URBs have been fully retired, with their completion |
| 465 | * routines run, even if that's not until some time after the original |
| 466 | * completion handler returns. Normally the same behavior and guarantees |
| 467 | * apply when an URB terminates because it was unlinked; however if an |
| 468 | * URB is unlinked before the hardware has started to execute it, then |
| 469 | * its queue is not guaranteed to stop until all the preceding URBs have |
| 470 | * completed. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 471 | * |
| 472 | * This means that USB device drivers can safely build deep queues for |
| 473 | * large or complex transfers, and clean them up reliably after any sort |
| 474 | * of aborted transfer by unlinking all pending URBs at the first fault. |
| 475 | * |
| 476 | * Note that an URB terminating early because a short packet was received |
| 477 | * will count as an error if and only if the URB_SHORT_NOT_OK flag is set. |
| 478 | * Also, that all unlinks performed in any URB completion handler must |
| 479 | * be asynchronous. |
| 480 | * |
| 481 | * Queues for isochronous endpoints are treated differently, because they |
| 482 | * advance at fixed rates. Such queues do not stop when an URB is unlinked. |
| 483 | * An unlinked URB may leave a gap in the stream of packets. It is undefined |
| 484 | * whether such gaps can be filled in. |
| 485 | * |
| 486 | * When a control URB terminates with an error, it is likely that the |
| 487 | * status stage of the transfer will not take place, even if it is merely |
| 488 | * a soft error resulting from a short-packet with URB_SHORT_NOT_OK set. |
| 489 | */ |
| 490 | int usb_unlink_urb(struct urb *urb) |
| 491 | { |
| 492 | if (!urb) |
| 493 | return -EINVAL; |
Alan Stern | a6d2bb9 | 2006-08-30 11:27:36 -0400 | [diff] [blame] | 494 | if (!(urb->dev && urb->dev->bus)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 495 | return -ENODEV; |
Alan Stern | a6d2bb9 | 2006-08-30 11:27:36 -0400 | [diff] [blame] | 496 | return usb_hcd_unlink_urb(urb, -ECONNRESET); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | } |
| 498 | |
| 499 | /** |
| 500 | * usb_kill_urb - cancel a transfer request and wait for it to finish |
| 501 | * @urb: pointer to URB describing a previously submitted request, |
| 502 | * may be NULL |
| 503 | * |
| 504 | * This routine cancels an in-progress request. It is guaranteed that |
| 505 | * upon return all completion handlers will have finished and the URB |
| 506 | * will be totally idle and available for reuse. These features make |
| 507 | * this an ideal way to stop I/O in a disconnect() callback or close() |
| 508 | * function. If the request has not already finished or been unlinked |
| 509 | * the completion handler will see urb->status == -ENOENT. |
| 510 | * |
| 511 | * While the routine is running, attempts to resubmit the URB will fail |
| 512 | * with error -EPERM. Thus even if the URB's completion handler always |
| 513 | * tries to resubmit, it will not succeed and the URB will become idle. |
| 514 | * |
| 515 | * This routine may not be used in an interrupt context (such as a bottom |
| 516 | * half or a completion handler), or when holding a spinlock, or in other |
| 517 | * situations where the caller can't schedule(). |
| 518 | */ |
| 519 | void usb_kill_urb(struct urb *urb) |
| 520 | { |
Greg Kroah-Hartman | e9aa795 | 2006-01-23 17:17:21 -0500 | [diff] [blame] | 521 | might_sleep(); |
Alan Stern | a6d2bb9 | 2006-08-30 11:27:36 -0400 | [diff] [blame] | 522 | if (!(urb && urb->dev && urb->dev->bus)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | return; |
| 524 | spin_lock_irq(&urb->lock); |
| 525 | ++urb->reject; |
| 526 | spin_unlock_irq(&urb->lock); |
| 527 | |
Alan Stern | a6d2bb9 | 2006-08-30 11:27:36 -0400 | [diff] [blame] | 528 | usb_hcd_unlink_urb(urb, -ENOENT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 529 | wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); |
| 530 | |
| 531 | spin_lock_irq(&urb->lock); |
| 532 | --urb->reject; |
| 533 | spin_unlock_irq(&urb->lock); |
| 534 | } |
| 535 | |
Oliver Neukum | 51a2f07 | 2007-05-25 13:40:56 +0200 | [diff] [blame] | 536 | /** |
| 537 | * usb_kill_anchored_urbs - cancel transfer requests en masse |
| 538 | * @anchor: anchor the requests are bound to |
| 539 | * |
| 540 | * this allows all outstanding URBs to be killed starting |
| 541 | * from the back of the queue |
| 542 | */ |
| 543 | void usb_kill_anchored_urbs(struct usb_anchor *anchor) |
| 544 | { |
| 545 | struct urb *victim; |
| 546 | |
| 547 | spin_lock_irq(&anchor->lock); |
| 548 | while (!list_empty(&anchor->urb_list)) { |
| 549 | victim = list_entry(anchor->urb_list.prev, struct urb, anchor_list); |
| 550 | /* we must make sure the URB isn't freed before we kill it*/ |
| 551 | usb_get_urb(victim); |
| 552 | spin_unlock_irq(&anchor->lock); |
| 553 | /* this will unanchor the URB */ |
| 554 | usb_kill_urb(victim); |
| 555 | usb_put_urb(victim); |
| 556 | spin_lock_irq(&anchor->lock); |
| 557 | } |
| 558 | spin_unlock_irq(&anchor->lock); |
| 559 | } |
| 560 | EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs); |
| 561 | |
| 562 | /** |
| 563 | * usb_wait_anchor_empty_timeout - wait for an anchor to be unused |
| 564 | * @anchor: the anchor you want to become unused |
| 565 | * @timeout: how long you are willing to wait in milliseconds |
| 566 | * |
| 567 | * Call this is you want to be sure all an anchor's |
| 568 | * URBs have finished |
| 569 | */ |
| 570 | int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor, |
| 571 | unsigned int timeout) |
| 572 | { |
| 573 | return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list), |
| 574 | msecs_to_jiffies(timeout)); |
| 575 | } |
| 576 | EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout); |
| 577 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 578 | EXPORT_SYMBOL(usb_init_urb); |
| 579 | EXPORT_SYMBOL(usb_alloc_urb); |
| 580 | EXPORT_SYMBOL(usb_free_urb); |
| 581 | EXPORT_SYMBOL(usb_get_urb); |
| 582 | EXPORT_SYMBOL(usb_submit_urb); |
| 583 | EXPORT_SYMBOL(usb_unlink_urb); |
| 584 | EXPORT_SYMBOL(usb_kill_urb); |