1 /* 2 * message.c - synchronous message handling 3 */ 4 5 #include <linux/pci.h> /* for scatterlist macros */ 6 #include <linux/usb.h> 7 #include <linux/module.h> 8 #include <linux/slab.h> 9 #include <linux/init.h> 10 #include <linux/mm.h> 11 #include <linux/timer.h> 12 #include <linux/ctype.h> 13 #include <linux/nls.h> 14 #include <linux/device.h> 15 #include <linux/scatterlist.h> 16 #include <linux/usb/quirks.h> 17 #include <linux/usb/hcd.h> /* for usbcore internals */ 18 #include <asm/byteorder.h> 19 20 #include "usb.h" 21 22 static void cancel_async_set_config(struct usb_device *udev); 23 24 struct api_context { 25 struct completion done; 26 int status; 27 }; 28 29 static void usb_api_blocking_completion(struct urb *urb) 30 { 31 struct api_context *ctx = urb->context; 32 33 ctx->status = urb->status; 34 complete(&ctx->done); 35 } 36 37 38 /* 39 * Starts urb and waits for completion or timeout. Note that this call 40 * is NOT interruptible. Many device driver i/o requests should be 41 * interruptible and therefore these drivers should implement their 42 * own interruptible routines. 43 */ 44 static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length) 45 { 46 struct api_context ctx; 47 unsigned long expire; 48 int retval; 49 50 init_completion(&ctx.done); 51 urb->context = &ctx; 52 urb->actual_length = 0; 53 retval = usb_submit_urb(urb, GFP_NOIO); 54 if (unlikely(retval)) 55 goto out; 56 57 expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT; 58 if (!wait_for_completion_timeout(&ctx.done, expire)) { 59 usb_kill_urb(urb); 60 retval = (ctx.status == -ENOENT ? -ETIMEDOUT : ctx.status); 61 62 dev_dbg(&urb->dev->dev, 63 "%s timed out on ep%d%s len=%u/%u\n", 64 current->comm, 65 usb_endpoint_num(&urb->ep->desc), 66 usb_urb_dir_in(urb) ? "in" : "out", 67 urb->actual_length, 68 urb->transfer_buffer_length); 69 } else 70 retval = ctx.status; 71 out: 72 if (actual_length) 73 *actual_length = urb->actual_length; 74 75 usb_free_urb(urb); 76 return retval; 77 } 78 79 /*-------------------------------------------------------------------*/ 80 /* returns status (negative) or length (positive) */ 81 static int usb_internal_control_msg(struct usb_device *usb_dev, 82 unsigned int pipe, 83 struct usb_ctrlrequest *cmd, 84 void *data, int len, int timeout) 85 { 86 struct urb *urb; 87 int retv; 88 int length; 89 90 urb = usb_alloc_urb(0, GFP_NOIO); 91 if (!urb) 92 return -ENOMEM; 93 94 usb_fill_control_urb(urb, usb_dev, pipe, (unsigned char *)cmd, data, 95 len, usb_api_blocking_completion, NULL); 96 97 retv = usb_start_wait_urb(urb, timeout, &length); 98 if (retv < 0) 99 return retv; 100 else 101 return length; 102 } 103 104 /** 105 * usb_control_msg - Builds a control urb, sends it off and waits for completion 106 * @dev: pointer to the usb device to send the message to 107 * @pipe: endpoint "pipe" to send the message to 108 * @request: USB message request value 109 * @requesttype: USB message request type value 110 * @value: USB message value 111 * @index: USB message index value 112 * @data: pointer to the data to send 113 * @size: length in bytes of the data to send 114 * @timeout: time in msecs to wait for the message to complete before timing 115 * out (if 0 the wait is forever) 116 * 117 * Context: !in_interrupt () 118 * 119 * This function sends a simple control message to a specified endpoint and 120 * waits for the message to complete, or timeout. 121 * 122 * If successful, it returns the number of bytes transferred, otherwise a 123 * negative error number. 124 * 125 * Don't use this function from within an interrupt context, like a bottom half 126 * handler. If you need an asynchronous message, or need to send a message 127 * from within interrupt context, use usb_submit_urb(). 128 * If a thread in your driver uses this call, make sure your disconnect() 129 * method can wait for it to complete. Since you don't have a handle on the 130 * URB used, you can't cancel the request. 131 */ 132 int usb_control_msg(struct usb_device *dev, unsigned int pipe, __u8 request, 133 __u8 requesttype, __u16 value, __u16 index, void *data, 134 __u16 size, int timeout) 135 { 136 struct usb_ctrlrequest *dr; 137 int ret; 138 139 dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_NOIO); 140 if (!dr) 141 return -ENOMEM; 142 143 dr->bRequestType = requesttype; 144 dr->bRequest = request; 145 dr->wValue = cpu_to_le16(value); 146 dr->wIndex = cpu_to_le16(index); 147 dr->wLength = cpu_to_le16(size); 148 149 ret = usb_internal_control_msg(dev, pipe, dr, data, size, timeout); 150 151 kfree(dr); 152 153 return ret; 154 } 155 EXPORT_SYMBOL_GPL(usb_control_msg); 156 157 /** 158 * usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for completion 159 * @usb_dev: pointer to the usb device to send the message to 160 * @pipe: endpoint "pipe" to send the message to 161 * @data: pointer to the data to send 162 * @len: length in bytes of the data to send 163 * @actual_length: pointer to a location to put the actual length transferred 164 * in bytes 165 * @timeout: time in msecs to wait for the message to complete before 166 * timing out (if 0 the wait is forever) 167 * 168 * Context: !in_interrupt () 169 * 170 * This function sends a simple interrupt message to a specified endpoint and 171 * waits for the message to complete, or timeout. 172 * 173 * If successful, it returns 0, otherwise a negative error number. The number 174 * of actual bytes transferred will be stored in the actual_length paramater. 175 * 176 * Don't use this function from within an interrupt context, like a bottom half 177 * handler. If you need an asynchronous message, or need to send a message 178 * from within interrupt context, use usb_submit_urb() If a thread in your 179 * driver uses this call, make sure your disconnect() method can wait for it to 180 * complete. Since you don't have a handle on the URB used, you can't cancel 181 * the request. 182 */ 183 int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe, 184 void *data, int len, int *actual_length, int timeout) 185 { 186 return usb_bulk_msg(usb_dev, pipe, data, len, actual_length, timeout); 187 } 188 EXPORT_SYMBOL_GPL(usb_interrupt_msg); 189 190 /** 191 * usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion 192 * @usb_dev: pointer to the usb device to send the message to 193 * @pipe: endpoint "pipe" to send the message to 194 * @data: pointer to the data to send 195 * @len: length in bytes of the data to send 196 * @actual_length: pointer to a location to put the actual length transferred 197 * in bytes 198 * @timeout: time in msecs to wait for the message to complete before 199 * timing out (if 0 the wait is forever) 200 * 201 * Context: !in_interrupt () 202 * 203 * This function sends a simple bulk message to a specified endpoint 204 * and waits for the message to complete, or timeout. 205 * 206 * If successful, it returns 0, otherwise a negative error number. The number 207 * of actual bytes transferred will be stored in the actual_length paramater. 208 * 209 * Don't use this function from within an interrupt context, like a bottom half 210 * handler. If you need an asynchronous message, or need to send a message 211 * from within interrupt context, use usb_submit_urb() If a thread in your 212 * driver uses this call, make sure your disconnect() method can wait for it to 213 * complete. Since you don't have a handle on the URB used, you can't cancel 214 * the request. 215 * 216 * Because there is no usb_interrupt_msg() and no USBDEVFS_INTERRUPT ioctl, 217 * users are forced to abuse this routine by using it to submit URBs for 218 * interrupt endpoints. We will take the liberty of creating an interrupt URB 219 * (with the default interval) if the target is an interrupt endpoint. 220 */ 221 int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe, 222 void *data, int len, int *actual_length, int timeout) 223 { 224 struct urb *urb; 225 struct usb_host_endpoint *ep; 226 227 ep = usb_pipe_endpoint(usb_dev, pipe); 228 if (!ep || len < 0) 229 return -EINVAL; 230 231 urb = usb_alloc_urb(0, GFP_KERNEL); 232 if (!urb) 233 return -ENOMEM; 234 235 if ((ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == 236 USB_ENDPOINT_XFER_INT) { 237 pipe = (pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30); 238 usb_fill_int_urb(urb, usb_dev, pipe, data, len, 239 usb_api_blocking_completion, NULL, 240 ep->desc.bInterval); 241 } else 242 usb_fill_bulk_urb(urb, usb_dev, pipe, data, len, 243 usb_api_blocking_completion, NULL); 244 245 return usb_start_wait_urb(urb, timeout, actual_length); 246 } 247 EXPORT_SYMBOL_GPL(usb_bulk_msg); 248 249 /*-------------------------------------------------------------------*/ 250 251 static void sg_clean(struct usb_sg_request *io) 252 { 253 if (io->urbs) { 254 while (io->entries--) 255 usb_free_urb(io->urbs [io->entries]); 256 kfree(io->urbs); 257 io->urbs = NULL; 258 } 259 io->dev = NULL; 260 } 261 262 static void sg_complete(struct urb *urb) 263 { 264 struct usb_sg_request *io = urb->context; 265 int status = urb->status; 266 267 spin_lock(&io->lock); 268 269 /* In 2.5 we require hcds' endpoint queues not to progress after fault 270 * reports, until the completion callback (this!) returns. That lets 271 * device driver code (like this routine) unlink queued urbs first, 272 * if it needs to, since the HC won't work on them at all. So it's 273 * not possible for page N+1 to overwrite page N, and so on. 274 * 275 * That's only for "hard" faults; "soft" faults (unlinks) sometimes 276 * complete before the HCD can get requests away from hardware, 277 * though never during cleanup after a hard fault. 278 */ 279 if (io->status 280 && (io->status != -ECONNRESET 281 || status != -ECONNRESET) 282 && urb->actual_length) { 283 dev_err(io->dev->bus->controller, 284 "dev %s ep%d%s scatterlist error %d/%d\n", 285 io->dev->devpath, 286 usb_endpoint_num(&urb->ep->desc), 287 usb_urb_dir_in(urb) ? "in" : "out", 288 status, io->status); 289 /* BUG (); */ 290 } 291 292 if (io->status == 0 && status && status != -ECONNRESET) { 293 int i, found, retval; 294 295 io->status = status; 296 297 /* the previous urbs, and this one, completed already. 298 * unlink pending urbs so they won't rx/tx bad data. 299 * careful: unlink can sometimes be synchronous... 300 */ 301 spin_unlock(&io->lock); 302 for (i = 0, found = 0; i < io->entries; i++) { 303 if (!io->urbs [i] || !io->urbs [i]->dev) 304 continue; 305 if (found) { 306 retval = usb_unlink_urb(io->urbs [i]); 307 if (retval != -EINPROGRESS && 308 retval != -ENODEV && 309 retval != -EBUSY && 310 retval != -EIDRM) 311 dev_err(&io->dev->dev, 312 "%s, unlink --> %d\n", 313 __func__, retval); 314 } else if (urb == io->urbs [i]) 315 found = 1; 316 } 317 spin_lock(&io->lock); 318 } 319 320 /* on the last completion, signal usb_sg_wait() */ 321 io->bytes += urb->actual_length; 322 io->count--; 323 if (!io->count) 324 complete(&io->complete); 325 326 spin_unlock(&io->lock); 327 } 328 329 330 /** 331 * usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request 332 * @io: request block being initialized. until usb_sg_wait() returns, 333 * treat this as a pointer to an opaque block of memory, 334 * @dev: the usb device that will send or receive the data 335 * @pipe: endpoint "pipe" used to transfer the data 336 * @period: polling rate for interrupt endpoints, in frames or 337 * (for high speed endpoints) microframes; ignored for bulk 338 * @sg: scatterlist entries 339 * @nents: how many entries in the scatterlist 340 * @length: how many bytes to send from the scatterlist, or zero to 341 * send every byte identified in the list. 342 * @mem_flags: SLAB_* flags affecting memory allocations in this call 343 * 344 * Returns zero for success, else a negative errno value. This initializes a 345 * scatter/gather request, allocating resources such as I/O mappings and urb 346 * memory (except maybe memory used by USB controller drivers). 347 * 348 * The request must be issued using usb_sg_wait(), which waits for the I/O to 349 * complete (or to be canceled) and then cleans up all resources allocated by 350 * usb_sg_init(). 351 * 352 * The request may be canceled with usb_sg_cancel(), either before or after 353 * usb_sg_wait() is called. 354 */ 355 int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev, 356 unsigned pipe, unsigned period, struct scatterlist *sg, 357 int nents, size_t length, gfp_t mem_flags) 358 { 359 int i; 360 int urb_flags; 361 int use_sg; 362 363 if (!io || !dev || !sg 364 || usb_pipecontrol(pipe) 365 || usb_pipeisoc(pipe) 366 || nents <= 0) 367 return -EINVAL; 368 369 spin_lock_init(&io->lock); 370 io->dev = dev; 371 io->pipe = pipe; 372 373 if (dev->bus->sg_tablesize > 0) { 374 use_sg = true; 375 io->entries = 1; 376 } else { 377 use_sg = false; 378 io->entries = nents; 379 } 380 381 /* initialize all the urbs we'll use */ 382 io->urbs = kmalloc(io->entries * sizeof *io->urbs, mem_flags); 383 if (!io->urbs) 384 goto nomem; 385 386 urb_flags = URB_NO_INTERRUPT; 387 if (usb_pipein(pipe)) 388 urb_flags |= URB_SHORT_NOT_OK; 389 390 for_each_sg(sg, sg, io->entries, i) { 391 struct urb *urb; 392 unsigned len; 393 394 urb = usb_alloc_urb(0, mem_flags); 395 if (!urb) { 396 io->entries = i; 397 goto nomem; 398 } 399 io->urbs[i] = urb; 400 401 urb->dev = NULL; 402 urb->pipe = pipe; 403 urb->interval = period; 404 urb->transfer_flags = urb_flags; 405 urb->complete = sg_complete; 406 urb->context = io; 407 urb->sg = sg; 408 409 if (use_sg) { 410 /* There is no single transfer buffer */ 411 urb->transfer_buffer = NULL; 412 urb->num_sgs = nents; 413 414 /* A length of zero means transfer the whole sg list */ 415 len = length; 416 if (len == 0) { 417 struct scatterlist *sg2; 418 int j; 419 420 for_each_sg(sg, sg2, nents, j) 421 len += sg2->length; 422 } 423 } else { 424 /* 425 * Some systems can't use DMA; they use PIO instead. 426 * For their sakes, transfer_buffer is set whenever 427 * possible. 428 */ 429 if (!PageHighMem(sg_page(sg))) 430 urb->transfer_buffer = sg_virt(sg); 431 else 432 urb->transfer_buffer = NULL; 433 434 len = sg->length; 435 if (length) { 436 len = min_t(size_t, len, length); 437 length -= len; 438 if (length == 0) 439 io->entries = i + 1; 440 } 441 } 442 urb->transfer_buffer_length = len; 443 } 444 io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT; 445 446 /* transaction state */ 447 io->count = io->entries; 448 io->status = 0; 449 io->bytes = 0; 450 init_completion(&io->complete); 451 return 0; 452 453 nomem: 454 sg_clean(io); 455 return -ENOMEM; 456 } 457 EXPORT_SYMBOL_GPL(usb_sg_init); 458 459 /** 460 * usb_sg_wait - synchronously execute scatter/gather request 461 * @io: request block handle, as initialized with usb_sg_init(). 462 * some fields become accessible when this call returns. 463 * Context: !in_interrupt () 464 * 465 * This function blocks until the specified I/O operation completes. It 466 * leverages the grouping of the related I/O requests to get good transfer 467 * rates, by queueing the requests. At higher speeds, such queuing can 468 * significantly improve USB throughput. 469 * 470 * There are three kinds of completion for this function. 471 * (1) success, where io->status is zero. The number of io->bytes 472 * transferred is as requested. 473 * (2) error, where io->status is a negative errno value. The number 474 * of io->bytes transferred before the error is usually less 475 * than requested, and can be nonzero. 476 * (3) cancellation, a type of error with status -ECONNRESET that 477 * is initiated by usb_sg_cancel(). 478 * 479 * When this function returns, all memory allocated through usb_sg_init() or 480 * this call will have been freed. The request block parameter may still be 481 * passed to usb_sg_cancel(), or it may be freed. It could also be 482 * reinitialized and then reused. 483 * 484 * Data Transfer Rates: 485 * 486 * Bulk transfers are valid for full or high speed endpoints. 487 * The best full speed data rate is 19 packets of 64 bytes each 488 * per frame, or 1216 bytes per millisecond. 489 * The best high speed data rate is 13 packets of 512 bytes each 490 * per microframe, or 52 KBytes per millisecond. 491 * 492 * The reason to use interrupt transfers through this API would most likely 493 * be to reserve high speed bandwidth, where up to 24 KBytes per millisecond 494 * could be transferred. That capability is less useful for low or full 495 * speed interrupt endpoints, which allow at most one packet per millisecond, 496 * of at most 8 or 64 bytes (respectively). 497 * 498 * It is not necessary to call this function to reserve bandwidth for devices 499 * under an xHCI host controller, as the bandwidth is reserved when the 500 * configuration or interface alt setting is selected. 501 */ 502 void usb_sg_wait(struct usb_sg_request *io) 503 { 504 int i; 505 int entries = io->entries; 506 507 /* queue the urbs. */ 508 spin_lock_irq(&io->lock); 509 i = 0; 510 while (i < entries && !io->status) { 511 int retval; 512 513 io->urbs[i]->dev = io->dev; 514 retval = usb_submit_urb(io->urbs [i], GFP_ATOMIC); 515 516 /* after we submit, let completions or cancelations fire; 517 * we handshake using io->status. 518 */ 519 spin_unlock_irq(&io->lock); 520 switch (retval) { 521 /* maybe we retrying will recover */ 522 case -ENXIO: /* hc didn't queue this one */ 523 case -EAGAIN: 524 case -ENOMEM: 525 retval = 0; 526 yield(); 527 break; 528 529 /* no error? continue immediately. 530 * 531 * NOTE: to work better with UHCI (4K I/O buffer may 532 * need 3K of TDs) it may be good to limit how many 533 * URBs are queued at once; N milliseconds? 534 */ 535 case 0: 536 ++i; 537 cpu_relax(); 538 break; 539 540 /* fail any uncompleted urbs */ 541 default: 542 io->urbs[i]->status = retval; 543 dev_dbg(&io->dev->dev, "%s, submit --> %d\n", 544 __func__, retval); 545 usb_sg_cancel(io); 546 } 547 spin_lock_irq(&io->lock); 548 if (retval && (io->status == 0 || io->status == -ECONNRESET)) 549 io->status = retval; 550 } 551 io->count -= entries - i; 552 if (io->count == 0) 553 complete(&io->complete); 554 spin_unlock_irq(&io->lock); 555 556 /* OK, yes, this could be packaged as non-blocking. 557 * So could the submit loop above ... but it's easier to 558 * solve neither problem than to solve both! 559 */ 560 wait_for_completion(&io->complete); 561 562 sg_clean(io); 563 } 564 EXPORT_SYMBOL_GPL(usb_sg_wait); 565 566 /** 567 * usb_sg_cancel - stop scatter/gather i/o issued by usb_sg_wait() 568 * @io: request block, initialized with usb_sg_init() 569 * 570 * This stops a request after it has been started by usb_sg_wait(). 571 * It can also prevents one initialized by usb_sg_init() from starting, 572 * so that call just frees resources allocated to the request. 573 */ 574 void usb_sg_cancel(struct usb_sg_request *io) 575 { 576 unsigned long flags; 577 578 spin_lock_irqsave(&io->lock, flags); 579 580 /* shut everything down, if it didn't already */ 581 if (!io->status) { 582 int i; 583 584 io->status = -ECONNRESET; 585 spin_unlock(&io->lock); 586 for (i = 0; i < io->entries; i++) { 587 int retval; 588 589 if (!io->urbs [i]->dev) 590 continue; 591 retval = usb_unlink_urb(io->urbs [i]); 592 if (retval != -EINPROGRESS 593 && retval != -ENODEV 594 && retval != -EBUSY 595 && retval != -EIDRM) 596 dev_warn(&io->dev->dev, "%s, unlink --> %d\n", 597 __func__, retval); 598 } 599 spin_lock(&io->lock); 600 } 601 spin_unlock_irqrestore(&io->lock, flags); 602 } 603 EXPORT_SYMBOL_GPL(usb_sg_cancel); 604 605 /*-------------------------------------------------------------------*/ 606 607 /** 608 * usb_get_descriptor - issues a generic GET_DESCRIPTOR request 609 * @dev: the device whose descriptor is being retrieved 610 * @type: the descriptor type (USB_DT_*) 611 * @index: the number of the descriptor 612 * @buf: where to put the descriptor 613 * @size: how big is "buf"? 614 * Context: !in_interrupt () 615 * 616 * Gets a USB descriptor. Convenience functions exist to simplify 617 * getting some types of descriptors. Use 618 * usb_get_string() or usb_string() for USB_DT_STRING. 619 * Device (USB_DT_DEVICE) and configuration descriptors (USB_DT_CONFIG) 620 * are part of the device structure. 621 * In addition to a number of USB-standard descriptors, some 622 * devices also use class-specific or vendor-specific descriptors. 623 * 624 * This call is synchronous, and may not be used in an interrupt context. 625 * 626 * Returns the number of bytes received on success, or else the status code 627 * returned by the underlying usb_control_msg() call. 628 */ 629 int usb_get_descriptor(struct usb_device *dev, unsigned char type, 630 unsigned char index, void *buf, int size) 631 { 632 int i; 633 int result; 634 635 memset(buf, 0, size); /* Make sure we parse really received data */ 636 637 for (i = 0; i < 3; ++i) { 638 /* retry on length 0 or error; some devices are flakey */ 639 result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), 640 USB_REQ_GET_DESCRIPTOR, USB_DIR_IN, 641 (type << 8) + index, 0, buf, size, 642 USB_CTRL_GET_TIMEOUT); 643 if (result <= 0 && result != -ETIMEDOUT) 644 continue; 645 if (result > 1 && ((u8 *)buf)[1] != type) { 646 result = -ENODATA; 647 continue; 648 } 649 break; 650 } 651 return result; 652 } 653 EXPORT_SYMBOL_GPL(usb_get_descriptor); 654 655 /** 656 * usb_get_string - gets a string descriptor 657 * @dev: the device whose string descriptor is being retrieved 658 * @langid: code for language chosen (from string descriptor zero) 659 * @index: the number of the descriptor 660 * @buf: where to put the string 661 * @size: how big is "buf"? 662 * Context: !in_interrupt () 663 * 664 * Retrieves a string, encoded using UTF-16LE (Unicode, 16 bits per character, 665 * in little-endian byte order). 666 * The usb_string() function will often be a convenient way to turn 667 * these strings into kernel-printable form. 668 * 669 * Strings may be referenced in device, configuration, interface, or other 670 * descriptors, and could also be used in vendor-specific ways. 671 * 672 * This call is synchronous, and may not be used in an interrupt context. 673 * 674 * Returns the number of bytes received on success, or else the status code 675 * returned by the underlying usb_control_msg() call. 676 */ 677 static int usb_get_string(struct usb_device *dev, unsigned short langid, 678 unsigned char index, void *buf, int size) 679 { 680 int i; 681 int result; 682 683 for (i = 0; i < 3; ++i) { 684 /* retry on length 0 or stall; some devices are flakey */ 685 result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), 686 USB_REQ_GET_DESCRIPTOR, USB_DIR_IN, 687 (USB_DT_STRING << 8) + index, langid, buf, size, 688 USB_CTRL_GET_TIMEOUT); 689 if (result == 0 || result == -EPIPE) 690 continue; 691 if (result > 1 && ((u8 *) buf)[1] != USB_DT_STRING) { 692 result = -ENODATA; 693 continue; 694 } 695 break; 696 } 697 return result; 698 } 699 700 static void usb_try_string_workarounds(unsigned char *buf, int *length) 701 { 702 int newlength, oldlength = *length; 703 704 for (newlength = 2; newlength + 1 < oldlength; newlength += 2) 705 if (!isprint(buf[newlength]) || buf[newlength + 1]) 706 break; 707 708 if (newlength > 2) { 709 buf[0] = newlength; 710 *length = newlength; 711 } 712 } 713 714 static int usb_string_sub(struct usb_device *dev, unsigned int langid, 715 unsigned int index, unsigned char *buf) 716 { 717 int rc; 718 719 /* Try to read the string descriptor by asking for the maximum 720 * possible number of bytes */ 721 if (dev->quirks & USB_QUIRK_STRING_FETCH_255) 722 rc = -EIO; 723 else 724 rc = usb_get_string(dev, langid, index, buf, 255); 725 726 /* If that failed try to read the descriptor length, then 727 * ask for just that many bytes */ 728 if (rc < 2) { 729 rc = usb_get_string(dev, langid, index, buf, 2); 730 if (rc == 2) 731 rc = usb_get_string(dev, langid, index, buf, buf[0]); 732 } 733 734 if (rc >= 2) { 735 if (!buf[0] && !buf[1]) 736 usb_try_string_workarounds(buf, &rc); 737 738 /* There might be extra junk at the end of the descriptor */ 739 if (buf[0] < rc) 740 rc = buf[0]; 741 742 rc = rc - (rc & 1); /* force a multiple of two */ 743 } 744 745 if (rc < 2) 746 rc = (rc < 0 ? rc : -EINVAL); 747 748 return rc; 749 } 750 751 static int usb_get_langid(struct usb_device *dev, unsigned char *tbuf) 752 { 753 int err; 754 755 if (dev->have_langid) 756 return 0; 757 758 if (dev->string_langid < 0) 759 return -EPIPE; 760 761 err = usb_string_sub(dev, 0, 0, tbuf); 762 763 /* If the string was reported but is malformed, default to english 764 * (0x0409) */ 765 if (err == -ENODATA || (err > 0 && err < 4)) { 766 dev->string_langid = 0x0409; 767 dev->have_langid = 1; 768 dev_err(&dev->dev, 769 "string descriptor 0 malformed (err = %d), " 770 "defaulting to 0x%04x\n", 771 err, dev->string_langid); 772 return 0; 773 } 774 775 /* In case of all other errors, we assume the device is not able to 776 * deal with strings at all. Set string_langid to -1 in order to 777 * prevent any string to be retrieved from the device */ 778 if (err < 0) { 779 dev_err(&dev->dev, "string descriptor 0 read error: %d\n", 780 err); 781 dev->string_langid = -1; 782 return -EPIPE; 783 } 784 785 /* always use the first langid listed */ 786 dev->string_langid = tbuf[2] | (tbuf[3] << 8); 787 dev->have_langid = 1; 788 dev_dbg(&dev->dev, "default language 0x%04x\n", 789 dev->string_langid); 790 return 0; 791 } 792 793 /** 794 * usb_string - returns UTF-8 version of a string descriptor 795 * @dev: the device whose string descriptor is being retrieved 796 * @index: the number of the descriptor 797 * @buf: where to put the string 798 * @size: how big is "buf"? 799 * Context: !in_interrupt () 800 * 801 * This converts the UTF-16LE encoded strings returned by devices, from 802 * usb_get_string_descriptor(), to null-terminated UTF-8 encoded ones 803 * that are more usable in most kernel contexts. Note that this function 804 * chooses strings in the first language supported by the device. 805 * 806 * This call is synchronous, and may not be used in an interrupt context. 807 * 808 * Returns length of the string (>= 0) or usb_control_msg status (< 0). 809 */ 810 int usb_string(struct usb_device *dev, int index, char *buf, size_t size) 811 { 812 unsigned char *tbuf; 813 int err; 814 815 if (dev->state == USB_STATE_SUSPENDED) 816 return -EHOSTUNREACH; 817 if (size <= 0 || !buf || !index) 818 return -EINVAL; 819 buf[0] = 0; 820 tbuf = kmalloc(256, GFP_NOIO); 821 if (!tbuf) 822 return -ENOMEM; 823 824 err = usb_get_langid(dev, tbuf); 825 if (err < 0) 826 goto errout; 827 828 err = usb_string_sub(dev, dev->string_langid, index, tbuf); 829 if (err < 0) 830 goto errout; 831 832 size--; /* leave room for trailing NULL char in output buffer */ 833 err = utf16s_to_utf8s((wchar_t *) &tbuf[2], (err - 2) / 2, 834 UTF16_LITTLE_ENDIAN, buf, size); 835 buf[err] = 0; 836 837 if (tbuf[1] != USB_DT_STRING) 838 dev_dbg(&dev->dev, 839 "wrong descriptor type %02x for string %d (\"%s\")\n", 840 tbuf[1], index, buf); 841 842 errout: 843 kfree(tbuf); 844 return err; 845 } 846 EXPORT_SYMBOL_GPL(usb_string); 847 848 /* one UTF-8-encoded 16-bit character has at most three bytes */ 849 #define MAX_USB_STRING_SIZE (127 * 3 + 1) 850 851 /** 852 * usb_cache_string - read a string descriptor and cache it for later use 853 * @udev: the device whose string descriptor is being read 854 * @index: the descriptor index 855 * 856 * Returns a pointer to a kmalloc'ed buffer containing the descriptor string, 857 * or NULL if the index is 0 or the string could not be read. 858 */ 859 char *usb_cache_string(struct usb_device *udev, int index) 860 { 861 char *buf; 862 char *smallbuf = NULL; 863 int len; 864 865 if (index <= 0) 866 return NULL; 867 868 buf = kmalloc(MAX_USB_STRING_SIZE, GFP_NOIO); 869 if (buf) { 870 len = usb_string(udev, index, buf, MAX_USB_STRING_SIZE); 871 if (len > 0) { 872 smallbuf = kmalloc(++len, GFP_NOIO); 873 if (!smallbuf) 874 return buf; 875 memcpy(smallbuf, buf, len); 876 } 877 kfree(buf); 878 } 879 return smallbuf; 880 } 881 882 /* 883 * usb_get_device_descriptor - (re)reads the device descriptor (usbcore) 884 * @dev: the device whose device descriptor is being updated 885 * @size: how much of the descriptor to read 886 * Context: !in_interrupt () 887 * 888 * Updates the copy of the device descriptor stored in the device structure, 889 * which dedicates space for this purpose. 890 * 891 * Not exported, only for use by the core. If drivers really want to read 892 * the device descriptor directly, they can call usb_get_descriptor() with 893 * type = USB_DT_DEVICE and index = 0. 894 * 895 * This call is synchronous, and may not be used in an interrupt context. 896 * 897 * Returns the number of bytes received on success, or else the status code 898 * returned by the underlying usb_control_msg() call. 899 */ 900 int usb_get_device_descriptor(struct usb_device *dev, unsigned int size) 901 { 902 struct usb_device_descriptor *desc; 903 int ret; 904 905 if (size > sizeof(*desc)) 906 return -EINVAL; 907 desc = kmalloc(sizeof(*desc), GFP_NOIO); 908 if (!desc) 909 return -ENOMEM; 910 911 ret = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, size); 912 if (ret >= 0) 913 memcpy(&dev->descriptor, desc, size); 914 kfree(desc); 915 return ret; 916 } 917 918 /** 919 * usb_get_status - issues a GET_STATUS call 920 * @dev: the device whose status is being checked 921 * @type: USB_RECIP_*; for device, interface, or endpoint 922 * @target: zero (for device), else interface or endpoint number 923 * @data: pointer to two bytes of bitmap data 924 * Context: !in_interrupt () 925 * 926 * Returns device, interface, or endpoint status. Normally only of 927 * interest to see if the device is self powered, or has enabled the 928 * remote wakeup facility; or whether a bulk or interrupt endpoint 929 * is halted ("stalled"). 930 * 931 * Bits in these status bitmaps are set using the SET_FEATURE request, 932 * and cleared using the CLEAR_FEATURE request. The usb_clear_halt() 933 * function should be used to clear halt ("stall") status. 934 * 935 * This call is synchronous, and may not be used in an interrupt context. 936 * 937 * Returns the number of bytes received on success, or else the status code 938 * returned by the underlying usb_control_msg() call. 939 */ 940 int usb_get_status(struct usb_device *dev, int type, int target, void *data) 941 { 942 int ret; 943 u16 *status = kmalloc(sizeof(*status), GFP_KERNEL); 944 945 if (!status) 946 return -ENOMEM; 947 948 ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), 949 USB_REQ_GET_STATUS, USB_DIR_IN | type, 0, target, status, 950 sizeof(*status), USB_CTRL_GET_TIMEOUT); 951 952 *(u16 *)data = *status; 953 kfree(status); 954 return ret; 955 } 956 EXPORT_SYMBOL_GPL(usb_get_status); 957 958 /** 959 * usb_clear_halt - tells device to clear endpoint halt/stall condition 960 * @dev: device whose endpoint is halted 961 * @pipe: endpoint "pipe" being cleared 962 * Context: !in_interrupt () 963 * 964 * This is used to clear halt conditions for bulk and interrupt endpoints, 965 * as reported by URB completion status. Endpoints that are halted are 966 * sometimes referred to as being "stalled". Such endpoints are unable 967 * to transmit or receive data until the halt status is cleared. Any URBs 968 * queued for such an endpoint should normally be unlinked by the driver 969 * before clearing the halt condition, as described in sections 5.7.5 970 * and 5.8.5 of the USB 2.0 spec. 971 * 972 * Note that control and isochronous endpoints don't halt, although control 973 * endpoints report "protocol stall" (for unsupported requests) using the 974 * same status code used to report a true stall. 975 * 976 * This call is synchronous, and may not be used in an interrupt context. 977 * 978 * Returns zero on success, or else the status code returned by the 979 * underlying usb_control_msg() call. 980 */ 981 int usb_clear_halt(struct usb_device *dev, int pipe) 982 { 983 int result; 984 int endp = usb_pipeendpoint(pipe); 985 986 if (usb_pipein(pipe)) 987 endp |= USB_DIR_IN; 988 989 /* we don't care if it wasn't halted first. in fact some devices 990 * (like some ibmcam model 1 units) seem to expect hosts to make 991 * this request for iso endpoints, which can't halt! 992 */ 993 result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), 994 USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT, 995 USB_ENDPOINT_HALT, endp, NULL, 0, 996 USB_CTRL_SET_TIMEOUT); 997 998 /* don't un-halt or force to DATA0 except on success */ 999 if (result < 0) 1000 return result; 1001 1002 /* NOTE: seems like Microsoft and Apple don't bother verifying 1003 * the clear "took", so some devices could lock up if you check... 1004 * such as the Hagiwara FlashGate DUAL. So we won't bother. 1005 * 1006 * NOTE: make sure the logic here doesn't diverge much from 1007 * the copy in usb-storage, for as long as we need two copies. 1008 */ 1009 1010 usb_reset_endpoint(dev, endp); 1011 1012 return 0; 1013 } 1014 EXPORT_SYMBOL_GPL(usb_clear_halt); 1015 1016 static int create_intf_ep_devs(struct usb_interface *intf) 1017 { 1018 struct usb_device *udev = interface_to_usbdev(intf); 1019 struct usb_host_interface *alt = intf->cur_altsetting; 1020 int i; 1021 1022 if (intf->ep_devs_created || intf->unregistering) 1023 return 0; 1024 1025 for (i = 0; i < alt->desc.bNumEndpoints; ++i) 1026 (void) usb_create_ep_devs(&intf->dev, &alt->endpoint[i], udev); 1027 intf->ep_devs_created = 1; 1028 return 0; 1029 } 1030 1031 static void remove_intf_ep_devs(struct usb_interface *intf) 1032 { 1033 struct usb_host_interface *alt = intf->cur_altsetting; 1034 int i; 1035 1036 if (!intf->ep_devs_created) 1037 return; 1038 1039 for (i = 0; i < alt->desc.bNumEndpoints; ++i) 1040 usb_remove_ep_devs(&alt->endpoint[i]); 1041 intf->ep_devs_created = 0; 1042 } 1043 1044 /** 1045 * usb_disable_endpoint -- Disable an endpoint by address 1046 * @dev: the device whose endpoint is being disabled 1047 * @epaddr: the endpoint's address. Endpoint number for output, 1048 * endpoint number + USB_DIR_IN for input 1049 * @reset_hardware: flag to erase any endpoint state stored in the 1050 * controller hardware 1051 * 1052 * Disables the endpoint for URB submission and nukes all pending URBs. 1053 * If @reset_hardware is set then also deallocates hcd/hardware state 1054 * for the endpoint. 1055 */ 1056 void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr, 1057 bool reset_hardware) 1058 { 1059 unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK; 1060 struct usb_host_endpoint *ep; 1061 1062 if (!dev) 1063 return; 1064 1065 if (usb_endpoint_out(epaddr)) { 1066 ep = dev->ep_out[epnum]; 1067 if (reset_hardware) 1068 dev->ep_out[epnum] = NULL; 1069 } else { 1070 ep = dev->ep_in[epnum]; 1071 if (reset_hardware) 1072 dev->ep_in[epnum] = NULL; 1073 } 1074 if (ep) { 1075 ep->enabled = 0; 1076 usb_hcd_flush_endpoint(dev, ep); 1077 if (reset_hardware) 1078 usb_hcd_disable_endpoint(dev, ep); 1079 } 1080 } 1081 1082 /** 1083 * usb_reset_endpoint - Reset an endpoint's state. 1084 * @dev: the device whose endpoint is to be reset 1085 * @epaddr: the endpoint's address. Endpoint number for output, 1086 * endpoint number + USB_DIR_IN for input 1087 * 1088 * Resets any host-side endpoint state such as the toggle bit, 1089 * sequence number or current window. 1090 */ 1091 void usb_reset_endpoint(struct usb_device *dev, unsigned int epaddr) 1092 { 1093 unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK; 1094 struct usb_host_endpoint *ep; 1095 1096 if (usb_endpoint_out(epaddr)) 1097 ep = dev->ep_out[epnum]; 1098 else 1099 ep = dev->ep_in[epnum]; 1100 if (ep) 1101 usb_hcd_reset_endpoint(dev, ep); 1102 } 1103 EXPORT_SYMBOL_GPL(usb_reset_endpoint); 1104 1105 1106 /** 1107 * usb_disable_interface -- Disable all endpoints for an interface 1108 * @dev: the device whose interface is being disabled 1109 * @intf: pointer to the interface descriptor 1110 * @reset_hardware: flag to erase any endpoint state stored in the 1111 * controller hardware 1112 * 1113 * Disables all the endpoints for the interface's current altsetting. 1114 */ 1115 void usb_disable_interface(struct usb_device *dev, struct usb_interface *intf, 1116 bool reset_hardware) 1117 { 1118 struct usb_host_interface *alt = intf->cur_altsetting; 1119 int i; 1120 1121 for (i = 0; i < alt->desc.bNumEndpoints; ++i) { 1122 usb_disable_endpoint(dev, 1123 alt->endpoint[i].desc.bEndpointAddress, 1124 reset_hardware); 1125 } 1126 } 1127 1128 /** 1129 * usb_disable_device - Disable all the endpoints for a USB device 1130 * @dev: the device whose endpoints are being disabled 1131 * @skip_ep0: 0 to disable endpoint 0, 1 to skip it. 1132 * 1133 * Disables all the device's endpoints, potentially including endpoint 0. 1134 * Deallocates hcd/hardware state for the endpoints (nuking all or most 1135 * pending urbs) and usbcore state for the interfaces, so that usbcore 1136 * must usb_set_configuration() before any interfaces could be used. 1137 */ 1138 void usb_disable_device(struct usb_device *dev, int skip_ep0) 1139 { 1140 int i; 1141 struct usb_hcd *hcd = bus_to_hcd(dev->bus); 1142 1143 /* getting rid of interfaces will disconnect 1144 * any drivers bound to them (a key side effect) 1145 */ 1146 if (dev->actconfig) { 1147 /* 1148 * FIXME: In order to avoid self-deadlock involving the 1149 * bandwidth_mutex, we have to mark all the interfaces 1150 * before unregistering any of them. 1151 */ 1152 for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) 1153 dev->actconfig->interface[i]->unregistering = 1; 1154 1155 for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) { 1156 struct usb_interface *interface; 1157 1158 /* remove this interface if it has been registered */ 1159 interface = dev->actconfig->interface[i]; 1160 if (!device_is_registered(&interface->dev)) 1161 continue; 1162 dev_dbg(&dev->dev, "unregistering interface %s\n", 1163 dev_name(&interface->dev)); 1164 remove_intf_ep_devs(interface); 1165 device_del(&interface->dev); 1166 } 1167 1168 /* Now that the interfaces are unbound, nobody should 1169 * try to access them. 1170 */ 1171 for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) { 1172 put_device(&dev->actconfig->interface[i]->dev); 1173 dev->actconfig->interface[i] = NULL; 1174 } 1175 usb_unlocked_disable_lpm(dev); 1176 usb_disable_ltm(dev); 1177 dev->actconfig = NULL; 1178 if (dev->state == USB_STATE_CONFIGURED) 1179 usb_set_device_state(dev, USB_STATE_ADDRESS); 1180 } 1181 1182 dev_dbg(&dev->dev, "%s nuking %s URBs\n", __func__, 1183 skip_ep0 ? "non-ep0" : "all"); 1184 if (hcd->driver->check_bandwidth) { 1185 /* First pass: Cancel URBs, leave endpoint pointers intact. */ 1186 for (i = skip_ep0; i < 16; ++i) { 1187 usb_disable_endpoint(dev, i, false); 1188 usb_disable_endpoint(dev, i + USB_DIR_IN, false); 1189 } 1190 /* Remove endpoints from the host controller internal state */ 1191 mutex_lock(hcd->bandwidth_mutex); 1192 usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL); 1193 mutex_unlock(hcd->bandwidth_mutex); 1194 /* Second pass: remove endpoint pointers */ 1195 } 1196 for (i = skip_ep0; i < 16; ++i) { 1197 usb_disable_endpoint(dev, i, true); 1198 usb_disable_endpoint(dev, i + USB_DIR_IN, true); 1199 } 1200 } 1201 1202 /** 1203 * usb_enable_endpoint - Enable an endpoint for USB communications 1204 * @dev: the device whose interface is being enabled 1205 * @ep: the endpoint 1206 * @reset_ep: flag to reset the endpoint state 1207 * 1208 * Resets the endpoint state if asked, and sets dev->ep_{in,out} pointers. 1209 * For control endpoints, both the input and output sides are handled. 1210 */ 1211 void usb_enable_endpoint(struct usb_device *dev, struct usb_host_endpoint *ep, 1212 bool reset_ep) 1213 { 1214 int epnum = usb_endpoint_num(&ep->desc); 1215 int is_out = usb_endpoint_dir_out(&ep->desc); 1216 int is_control = usb_endpoint_xfer_control(&ep->desc); 1217 1218 if (reset_ep) 1219 usb_hcd_reset_endpoint(dev, ep); 1220 if (is_out || is_control) 1221 dev->ep_out[epnum] = ep; 1222 if (!is_out || is_control) 1223 dev->ep_in[epnum] = ep; 1224 ep->enabled = 1; 1225 } 1226 1227 /** 1228 * usb_enable_interface - Enable all the endpoints for an interface 1229 * @dev: the device whose interface is being enabled 1230 * @intf: pointer to the interface descriptor 1231 * @reset_eps: flag to reset the endpoints' state 1232 * 1233 * Enables all the endpoints for the interface's current altsetting. 1234 */ 1235 void usb_enable_interface(struct usb_device *dev, 1236 struct usb_interface *intf, bool reset_eps) 1237 { 1238 struct usb_host_interface *alt = intf->cur_altsetting; 1239 int i; 1240 1241 for (i = 0; i < alt->desc.bNumEndpoints; ++i) 1242 usb_enable_endpoint(dev, &alt->endpoint[i], reset_eps); 1243 } 1244 1245 /** 1246 * usb_set_interface - Makes a particular alternate setting be current 1247 * @dev: the device whose interface is being updated 1248 * @interface: the interface being updated 1249 * @alternate: the setting being chosen. 1250 * Context: !in_interrupt () 1251 * 1252 * This is used to enable data transfers on interfaces that may not 1253 * be enabled by default. Not all devices support such configurability. 1254 * Only the driver bound to an interface may change its setting. 1255 * 1256 * Within any given configuration, each interface may have several 1257 * alternative settings. These are often used to control levels of 1258 * bandwidth consumption. For example, the default setting for a high 1259 * speed interrupt endpoint may not send more than 64 bytes per microframe, 1260 * while interrupt transfers of up to 3KBytes per microframe are legal. 1261 * Also, isochronous endpoints may never be part of an 1262 * interface's default setting. To access such bandwidth, alternate 1263 * interface settings must be made current. 1264 * 1265 * Note that in the Linux USB subsystem, bandwidth associated with 1266 * an endpoint in a given alternate setting is not reserved until an URB 1267 * is submitted that needs that bandwidth. Some other operating systems 1268 * allocate bandwidth early, when a configuration is chosen. 1269 * 1270 * This call is synchronous, and may not be used in an interrupt context. 1271 * Also, drivers must not change altsettings while urbs are scheduled for 1272 * endpoints in that interface; all such urbs must first be completed 1273 * (perhaps forced by unlinking). 1274 * 1275 * Returns zero on success, or else the status code returned by the 1276 * underlying usb_control_msg() call. 1277 */ 1278 int usb_set_interface(struct usb_device *dev, int interface, int alternate) 1279 { 1280 struct usb_interface *iface; 1281 struct usb_host_interface *alt; 1282 struct usb_hcd *hcd = bus_to_hcd(dev->bus); 1283 int ret; 1284 int manual = 0; 1285 unsigned int epaddr; 1286 unsigned int pipe; 1287 1288 if (dev->state == USB_STATE_SUSPENDED) 1289 return -EHOSTUNREACH; 1290 1291 iface = usb_ifnum_to_if(dev, interface); 1292 if (!iface) { 1293 dev_dbg(&dev->dev, "selecting invalid interface %d\n", 1294 interface); 1295 return -EINVAL; 1296 } 1297 if (iface->unregistering) 1298 return -ENODEV; 1299 1300 alt = usb_altnum_to_altsetting(iface, alternate); 1301 if (!alt) { 1302 dev_warn(&dev->dev, "selecting invalid altsetting %d\n", 1303 alternate); 1304 return -EINVAL; 1305 } 1306 1307 /* Make sure we have enough bandwidth for this alternate interface. 1308 * Remove the current alt setting and add the new alt setting. 1309 */ 1310 mutex_lock(hcd->bandwidth_mutex); 1311 /* Disable LPM, and re-enable it once the new alt setting is installed, 1312 * so that the xHCI driver can recalculate the U1/U2 timeouts. 1313 */ 1314 if (usb_disable_lpm(dev)) { 1315 dev_err(&iface->dev, "%s Failed to disable LPM\n.", __func__); 1316 mutex_unlock(hcd->bandwidth_mutex); 1317 return -ENOMEM; 1318 } 1319 ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt); 1320 if (ret < 0) { 1321 dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n", 1322 alternate); 1323 usb_enable_lpm(dev); 1324 mutex_unlock(hcd->bandwidth_mutex); 1325 return ret; 1326 } 1327 1328 if (dev->quirks & USB_QUIRK_NO_SET_INTF) 1329 ret = -EPIPE; 1330 else 1331 ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), 1332 USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE, 1333 alternate, interface, NULL, 0, 5000); 1334 1335 /* 9.4.10 says devices don't need this and are free to STALL the 1336 * request if the interface only has one alternate setting. 1337 */ 1338 if (ret == -EPIPE && iface->num_altsetting == 1) { 1339 dev_dbg(&dev->dev, 1340 "manual set_interface for iface %d, alt %d\n", 1341 interface, alternate); 1342 manual = 1; 1343 } else if (ret < 0) { 1344 /* Re-instate the old alt setting */ 1345 usb_hcd_alloc_bandwidth(dev, NULL, alt, iface->cur_altsetting); 1346 usb_enable_lpm(dev); 1347 mutex_unlock(hcd->bandwidth_mutex); 1348 return ret; 1349 } 1350 mutex_unlock(hcd->bandwidth_mutex); 1351 1352 /* FIXME drivers shouldn't need to replicate/bugfix the logic here 1353 * when they implement async or easily-killable versions of this or 1354 * other "should-be-internal" functions (like clear_halt). 1355 * should hcd+usbcore postprocess control requests? 1356 */ 1357 1358 /* prevent submissions using previous endpoint settings */ 1359 if (iface->cur_altsetting != alt) { 1360 remove_intf_ep_devs(iface); 1361 usb_remove_sysfs_intf_files(iface); 1362 } 1363 usb_disable_interface(dev, iface, true); 1364 1365 iface->cur_altsetting = alt; 1366 1367 /* Now that the interface is installed, re-enable LPM. */ 1368 usb_unlocked_enable_lpm(dev); 1369 1370 /* If the interface only has one altsetting and the device didn't 1371 * accept the request, we attempt to carry out the equivalent action 1372 * by manually clearing the HALT feature for each endpoint in the 1373 * new altsetting. 1374 */ 1375 if (manual) { 1376 int i; 1377 1378 for (i = 0; i < alt->desc.bNumEndpoints; i++) { 1379 epaddr = alt->endpoint[i].desc.bEndpointAddress; 1380 pipe = __create_pipe(dev, 1381 USB_ENDPOINT_NUMBER_MASK & epaddr) | 1382 (usb_endpoint_out(epaddr) ? 1383 USB_DIR_OUT : USB_DIR_IN); 1384 1385 usb_clear_halt(dev, pipe); 1386 } 1387 } 1388 1389 /* 9.1.1.5: reset toggles for all endpoints in the new altsetting 1390 * 1391 * Note: 1392 * Despite EP0 is always present in all interfaces/AS, the list of 1393 * endpoints from the descriptor does not contain EP0. Due to its 1394 * omnipresence one might expect EP0 being considered "affected" by 1395 * any SetInterface request and hence assume toggles need to be reset. 1396 * However, EP0 toggles are re-synced for every individual transfer 1397 * during the SETUP stage - hence EP0 toggles are "don't care" here. 1398 * (Likewise, EP0 never "halts" on well designed devices.) 1399 */ 1400 usb_enable_interface(dev, iface, true); 1401 if (device_is_registered(&iface->dev)) { 1402 usb_create_sysfs_intf_files(iface); 1403 create_intf_ep_devs(iface); 1404 } 1405 return 0; 1406 } 1407 EXPORT_SYMBOL_GPL(usb_set_interface); 1408 1409 /** 1410 * usb_reset_configuration - lightweight device reset 1411 * @dev: the device whose configuration is being reset 1412 * 1413 * This issues a standard SET_CONFIGURATION request to the device using 1414 * the current configuration. The effect is to reset most USB-related 1415 * state in the device, including interface altsettings (reset to zero), 1416 * endpoint halts (cleared), and endpoint state (only for bulk and interrupt 1417 * endpoints). Other usbcore state is unchanged, including bindings of 1418 * usb device drivers to interfaces. 1419 * 1420 * Because this affects multiple interfaces, avoid using this with composite 1421 * (multi-interface) devices. Instead, the driver for each interface may 1422 * use usb_set_interface() on the interfaces it claims. Be careful though; 1423 * some devices don't support the SET_INTERFACE request, and others won't 1424 * reset all the interface state (notably endpoint state). Resetting the whole 1425 * configuration would affect other drivers' interfaces. 1426 * 1427 * The caller must own the device lock. 1428 * 1429 * Returns zero on success, else a negative error code. 1430 */ 1431 int usb_reset_configuration(struct usb_device *dev) 1432 { 1433 int i, retval; 1434 struct usb_host_config *config; 1435 struct usb_hcd *hcd = bus_to_hcd(dev->bus); 1436 1437 if (dev->state == USB_STATE_SUSPENDED) 1438 return -EHOSTUNREACH; 1439 1440 /* caller must have locked the device and must own 1441 * the usb bus readlock (so driver bindings are stable); 1442 * calls during probe() are fine 1443 */ 1444 1445 for (i = 1; i < 16; ++i) { 1446 usb_disable_endpoint(dev, i, true); 1447 usb_disable_endpoint(dev, i + USB_DIR_IN, true); 1448 } 1449 1450 config = dev->actconfig; 1451 retval = 0; 1452 mutex_lock(hcd->bandwidth_mutex); 1453 /* Disable LPM, and re-enable it once the configuration is reset, so 1454 * that the xHCI driver can recalculate the U1/U2 timeouts. 1455 */ 1456 if (usb_disable_lpm(dev)) { 1457 dev_err(&dev->dev, "%s Failed to disable LPM\n.", __func__); 1458 mutex_unlock(hcd->bandwidth_mutex); 1459 return -ENOMEM; 1460 } 1461 /* Make sure we have enough bandwidth for each alternate setting 0 */ 1462 for (i = 0; i < config->desc.bNumInterfaces; i++) { 1463 struct usb_interface *intf = config->interface[i]; 1464 struct usb_host_interface *alt; 1465 1466 alt = usb_altnum_to_altsetting(intf, 0); 1467 if (!alt) 1468 alt = &intf->altsetting[0]; 1469 if (alt != intf->cur_altsetting) 1470 retval = usb_hcd_alloc_bandwidth(dev, NULL, 1471 intf->cur_altsetting, alt); 1472 if (retval < 0) 1473 break; 1474 } 1475 /* If not, reinstate the old alternate settings */ 1476 if (retval < 0) { 1477 reset_old_alts: 1478 for (i--; i >= 0; i--) { 1479 struct usb_interface *intf = config->interface[i]; 1480 struct usb_host_interface *alt; 1481 1482 alt = usb_altnum_to_altsetting(intf, 0); 1483 if (!alt) 1484 alt = &intf->altsetting[0]; 1485 if (alt != intf->cur_altsetting) 1486 usb_hcd_alloc_bandwidth(dev, NULL, 1487 alt, intf->cur_altsetting); 1488 } 1489 usb_enable_lpm(dev); 1490 mutex_unlock(hcd->bandwidth_mutex); 1491 return retval; 1492 } 1493 retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), 1494 USB_REQ_SET_CONFIGURATION, 0, 1495 config->desc.bConfigurationValue, 0, 1496 NULL, 0, USB_CTRL_SET_TIMEOUT); 1497 if (retval < 0) 1498 goto reset_old_alts; 1499 mutex_unlock(hcd->bandwidth_mutex); 1500 1501 /* re-init hc/hcd interface/endpoint state */ 1502 for (i = 0; i < config->desc.bNumInterfaces; i++) { 1503 struct usb_interface *intf = config->interface[i]; 1504 struct usb_host_interface *alt; 1505 1506 alt = usb_altnum_to_altsetting(intf, 0); 1507 1508 /* No altsetting 0? We'll assume the first altsetting. 1509 * We could use a GetInterface call, but if a device is 1510 * so non-compliant that it doesn't have altsetting 0 1511 * then I wouldn't trust its reply anyway. 1512 */ 1513 if (!alt) 1514 alt = &intf->altsetting[0]; 1515 1516 if (alt != intf->cur_altsetting) { 1517 remove_intf_ep_devs(intf); 1518 usb_remove_sysfs_intf_files(intf); 1519 } 1520 intf->cur_altsetting = alt; 1521 usb_enable_interface(dev, intf, true); 1522 if (device_is_registered(&intf->dev)) { 1523 usb_create_sysfs_intf_files(intf); 1524 create_intf_ep_devs(intf); 1525 } 1526 } 1527 /* Now that the interfaces are installed, re-enable LPM. */ 1528 usb_unlocked_enable_lpm(dev); 1529 return 0; 1530 } 1531 EXPORT_SYMBOL_GPL(usb_reset_configuration); 1532 1533 static void usb_release_interface(struct device *dev) 1534 { 1535 struct usb_interface *intf = to_usb_interface(dev); 1536 struct usb_interface_cache *intfc = 1537 altsetting_to_usb_interface_cache(intf->altsetting); 1538 1539 kref_put(&intfc->ref, usb_release_interface_cache); 1540 kfree(intf); 1541 } 1542 1543 #ifdef CONFIG_HOTPLUG 1544 static int usb_if_uevent(struct device *dev, struct kobj_uevent_env *env) 1545 { 1546 struct usb_device *usb_dev; 1547 struct usb_interface *intf; 1548 struct usb_host_interface *alt; 1549 1550 intf = to_usb_interface(dev); 1551 usb_dev = interface_to_usbdev(intf); 1552 alt = intf->cur_altsetting; 1553 1554 if (add_uevent_var(env, "INTERFACE=%d/%d/%d", 1555 alt->desc.bInterfaceClass, 1556 alt->desc.bInterfaceSubClass, 1557 alt->desc.bInterfaceProtocol)) 1558 return -ENOMEM; 1559 1560 if (add_uevent_var(env, 1561 "MODALIAS=usb:" 1562 "v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02Xin%02X", 1563 le16_to_cpu(usb_dev->descriptor.idVendor), 1564 le16_to_cpu(usb_dev->descriptor.idProduct), 1565 le16_to_cpu(usb_dev->descriptor.bcdDevice), 1566 usb_dev->descriptor.bDeviceClass, 1567 usb_dev->descriptor.bDeviceSubClass, 1568 usb_dev->descriptor.bDeviceProtocol, 1569 alt->desc.bInterfaceClass, 1570 alt->desc.bInterfaceSubClass, 1571 alt->desc.bInterfaceProtocol, 1572 alt->desc.bInterfaceNumber)) 1573 return -ENOMEM; 1574 1575 return 0; 1576 } 1577 1578 #else 1579 1580 static int usb_if_uevent(struct device *dev, struct kobj_uevent_env *env) 1581 { 1582 return -ENODEV; 1583 } 1584 #endif /* CONFIG_HOTPLUG */ 1585 1586 struct device_type usb_if_device_type = { 1587 .name = "usb_interface", 1588 .release = usb_release_interface, 1589 .uevent = usb_if_uevent, 1590 }; 1591 1592 static struct usb_interface_assoc_descriptor *find_iad(struct usb_device *dev, 1593 struct usb_host_config *config, 1594 u8 inum) 1595 { 1596 struct usb_interface_assoc_descriptor *retval = NULL; 1597 struct usb_interface_assoc_descriptor *intf_assoc; 1598 int first_intf; 1599 int last_intf; 1600 int i; 1601 1602 for (i = 0; (i < USB_MAXIADS && config->intf_assoc[i]); i++) { 1603 intf_assoc = config->intf_assoc[i]; 1604 if (intf_assoc->bInterfaceCount == 0) 1605 continue; 1606 1607 first_intf = intf_assoc->bFirstInterface; 1608 last_intf = first_intf + (intf_assoc->bInterfaceCount - 1); 1609 if (inum >= first_intf && inum <= last_intf) { 1610 if (!retval) 1611 retval = intf_assoc; 1612 else 1613 dev_err(&dev->dev, "Interface #%d referenced" 1614 " by multiple IADs\n", inum); 1615 } 1616 } 1617 1618 return retval; 1619 } 1620 1621 1622 /* 1623 * Internal function to queue a device reset 1624 * 1625 * This is initialized into the workstruct in 'struct 1626 * usb_device->reset_ws' that is launched by 1627 * message.c:usb_set_configuration() when initializing each 'struct 1628 * usb_interface'. 1629 * 1630 * It is safe to get the USB device without reference counts because 1631 * the life cycle of @iface is bound to the life cycle of @udev. Then, 1632 * this function will be ran only if @iface is alive (and before 1633 * freeing it any scheduled instances of it will have been cancelled). 1634 * 1635 * We need to set a flag (usb_dev->reset_running) because when we call 1636 * the reset, the interfaces might be unbound. The current interface 1637 * cannot try to remove the queued work as it would cause a deadlock 1638 * (you cannot remove your work from within your executing 1639 * workqueue). This flag lets it know, so that 1640 * usb_cancel_queued_reset() doesn't try to do it. 1641 * 1642 * See usb_queue_reset_device() for more details 1643 */ 1644 static void __usb_queue_reset_device(struct work_struct *ws) 1645 { 1646 int rc; 1647 struct usb_interface *iface = 1648 container_of(ws, struct usb_interface, reset_ws); 1649 struct usb_device *udev = interface_to_usbdev(iface); 1650 1651 rc = usb_lock_device_for_reset(udev, iface); 1652 if (rc >= 0) { 1653 iface->reset_running = 1; 1654 usb_reset_device(udev); 1655 iface->reset_running = 0; 1656 usb_unlock_device(udev); 1657 } 1658 } 1659 1660 1661 /* 1662 * usb_set_configuration - Makes a particular device setting be current 1663 * @dev: the device whose configuration is being updated 1664 * @configuration: the configuration being chosen. 1665 * Context: !in_interrupt(), caller owns the device lock 1666 * 1667 * This is used to enable non-default device modes. Not all devices 1668 * use this kind of configurability; many devices only have one 1669 * configuration. 1670 * 1671 * @configuration is the value of the configuration to be installed. 1672 * According to the USB spec (e.g. section 9.1.1.5), configuration values 1673 * must be non-zero; a value of zero indicates that the device in 1674 * unconfigured. However some devices erroneously use 0 as one of their 1675 * configuration values. To help manage such devices, this routine will 1676 * accept @configuration = -1 as indicating the device should be put in 1677 * an unconfigured state. 1678 * 1679 * USB device configurations may affect Linux interoperability, 1680 * power consumption and the functionality available. For example, 1681 * the default configuration is limited to using 100mA of bus power, 1682 * so that when certain device functionality requires more power, 1683 * and the device is bus powered, that functionality should be in some 1684 * non-default device configuration. Other device modes may also be 1685 * reflected as configuration options, such as whether two ISDN 1686 * channels are available independently; and choosing between open 1687 * standard device protocols (like CDC) or proprietary ones. 1688 * 1689 * Note that a non-authorized device (dev->authorized == 0) will only 1690 * be put in unconfigured mode. 1691 * 1692 * Note that USB has an additional level of device configurability, 1693 * associated with interfaces. That configurability is accessed using 1694 * usb_set_interface(). 1695 * 1696 * This call is synchronous. The calling context must be able to sleep, 1697 * must own the device lock, and must not hold the driver model's USB 1698 * bus mutex; usb interface driver probe() methods cannot use this routine. 1699 * 1700 * Returns zero on success, or else the status code returned by the 1701 * underlying call that failed. On successful completion, each interface 1702 * in the original device configuration has been destroyed, and each one 1703 * in the new configuration has been probed by all relevant usb device 1704 * drivers currently known to the kernel. 1705 */ 1706 int usb_set_configuration(struct usb_device *dev, int configuration) 1707 { 1708 int i, ret; 1709 struct usb_host_config *cp = NULL; 1710 struct usb_interface **new_interfaces = NULL; 1711 struct usb_hcd *hcd = bus_to_hcd(dev->bus); 1712 int n, nintf; 1713 1714 if (dev->authorized == 0 || configuration == -1) 1715 configuration = 0; 1716 else { 1717 for (i = 0; i < dev->descriptor.bNumConfigurations; i++) { 1718 if (dev->config[i].desc.bConfigurationValue == 1719 configuration) { 1720 cp = &dev->config[i]; 1721 break; 1722 } 1723 } 1724 } 1725 if ((!cp && configuration != 0)) 1726 return -EINVAL; 1727 1728 /* The USB spec says configuration 0 means unconfigured. 1729 * But if a device includes a configuration numbered 0, 1730 * we will accept it as a correctly configured state. 1731 * Use -1 if you really want to unconfigure the device. 1732 */ 1733 if (cp && configuration == 0) 1734 dev_warn(&dev->dev, "config 0 descriptor??\n"); 1735 1736 /* Allocate memory for new interfaces before doing anything else, 1737 * so that if we run out then nothing will have changed. */ 1738 n = nintf = 0; 1739 if (cp) { 1740 nintf = cp->desc.bNumInterfaces; 1741 new_interfaces = kmalloc(nintf * sizeof(*new_interfaces), 1742 GFP_NOIO); 1743 if (!new_interfaces) { 1744 dev_err(&dev->dev, "Out of memory\n"); 1745 return -ENOMEM; 1746 } 1747 1748 for (; n < nintf; ++n) { 1749 new_interfaces[n] = kzalloc( 1750 sizeof(struct usb_interface), 1751 GFP_NOIO); 1752 if (!new_interfaces[n]) { 1753 dev_err(&dev->dev, "Out of memory\n"); 1754 ret = -ENOMEM; 1755 free_interfaces: 1756 while (--n >= 0) 1757 kfree(new_interfaces[n]); 1758 kfree(new_interfaces); 1759 return ret; 1760 } 1761 } 1762 1763 i = dev->bus_mA - cp->desc.bMaxPower * 2; 1764 if (i < 0) 1765 dev_warn(&dev->dev, "new config #%d exceeds power " 1766 "limit by %dmA\n", 1767 configuration, -i); 1768 } 1769 1770 /* Wake up the device so we can send it the Set-Config request */ 1771 ret = usb_autoresume_device(dev); 1772 if (ret) 1773 goto free_interfaces; 1774 1775 /* if it's already configured, clear out old state first. 1776 * getting rid of old interfaces means unbinding their drivers. 1777 */ 1778 if (dev->state != USB_STATE_ADDRESS) 1779 usb_disable_device(dev, 1); /* Skip ep0 */ 1780 1781 /* Get rid of pending async Set-Config requests for this device */ 1782 cancel_async_set_config(dev); 1783 1784 /* Make sure we have bandwidth (and available HCD resources) for this 1785 * configuration. Remove endpoints from the schedule if we're dropping 1786 * this configuration to set configuration 0. After this point, the 1787 * host controller will not allow submissions to dropped endpoints. If 1788 * this call fails, the device state is unchanged. 1789 */ 1790 mutex_lock(hcd->bandwidth_mutex); 1791 /* Disable LPM, and re-enable it once the new configuration is 1792 * installed, so that the xHCI driver can recalculate the U1/U2 1793 * timeouts. 1794 */ 1795 if (dev->actconfig && usb_disable_lpm(dev)) { 1796 dev_err(&dev->dev, "%s Failed to disable LPM\n.", __func__); 1797 mutex_unlock(hcd->bandwidth_mutex); 1798 return -ENOMEM; 1799 } 1800 ret = usb_hcd_alloc_bandwidth(dev, cp, NULL, NULL); 1801 if (ret < 0) { 1802 if (dev->actconfig) 1803 usb_enable_lpm(dev); 1804 mutex_unlock(hcd->bandwidth_mutex); 1805 usb_autosuspend_device(dev); 1806 goto free_interfaces; 1807 } 1808 1809 ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), 1810 USB_REQ_SET_CONFIGURATION, 0, configuration, 0, 1811 NULL, 0, USB_CTRL_SET_TIMEOUT); 1812 if (ret < 0) { 1813 /* All the old state is gone, so what else can we do? 1814 * The device is probably useless now anyway. 1815 */ 1816 cp = NULL; 1817 } 1818 1819 dev->actconfig = cp; 1820 if (!cp) { 1821 usb_set_device_state(dev, USB_STATE_ADDRESS); 1822 usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL); 1823 /* Leave LPM disabled while the device is unconfigured. */ 1824 mutex_unlock(hcd->bandwidth_mutex); 1825 usb_autosuspend_device(dev); 1826 goto free_interfaces; 1827 } 1828 mutex_unlock(hcd->bandwidth_mutex); 1829 usb_set_device_state(dev, USB_STATE_CONFIGURED); 1830 1831 /* Initialize the new interface structures and the 1832 * hc/hcd/usbcore interface/endpoint state. 1833 */ 1834 for (i = 0; i < nintf; ++i) { 1835 struct usb_interface_cache *intfc; 1836 struct usb_interface *intf; 1837 struct usb_host_interface *alt; 1838 1839 cp->interface[i] = intf = new_interfaces[i]; 1840 intfc = cp->intf_cache[i]; 1841 intf->altsetting = intfc->altsetting; 1842 intf->num_altsetting = intfc->num_altsetting; 1843 kref_get(&intfc->ref); 1844 1845 alt = usb_altnum_to_altsetting(intf, 0); 1846 1847 /* No altsetting 0? We'll assume the first altsetting. 1848 * We could use a GetInterface call, but if a device is 1849 * so non-compliant that it doesn't have altsetting 0 1850 * then I wouldn't trust its reply anyway. 1851 */ 1852 if (!alt) 1853 alt = &intf->altsetting[0]; 1854 1855 intf->intf_assoc = 1856 find_iad(dev, cp, alt->desc.bInterfaceNumber); 1857 intf->cur_altsetting = alt; 1858 usb_enable_interface(dev, intf, true); 1859 intf->dev.parent = &dev->dev; 1860 intf->dev.driver = NULL; 1861 intf->dev.bus = &usb_bus_type; 1862 intf->dev.type = &usb_if_device_type; 1863 intf->dev.groups = usb_interface_groups; 1864 intf->dev.dma_mask = dev->dev.dma_mask; 1865 INIT_WORK(&intf->reset_ws, __usb_queue_reset_device); 1866 intf->minor = -1; 1867 device_initialize(&intf->dev); 1868 pm_runtime_no_callbacks(&intf->dev); 1869 dev_set_name(&intf->dev, "%d-%s:%d.%d", 1870 dev->bus->busnum, dev->devpath, 1871 configuration, alt->desc.bInterfaceNumber); 1872 } 1873 kfree(new_interfaces); 1874 1875 if (cp->string == NULL && 1876 !(dev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS)) 1877 cp->string = usb_cache_string(dev, cp->desc.iConfiguration); 1878 1879 /* Now that the interfaces are installed, re-enable LPM. */ 1880 usb_unlocked_enable_lpm(dev); 1881 /* Enable LTM if it was turned off by usb_disable_device. */ 1882 usb_enable_ltm(dev); 1883 1884 /* Now that all the interfaces are set up, register them 1885 * to trigger binding of drivers to interfaces. probe() 1886 * routines may install different altsettings and may 1887 * claim() any interfaces not yet bound. Many class drivers 1888 * need that: CDC, audio, video, etc. 1889 */ 1890 for (i = 0; i < nintf; ++i) { 1891 struct usb_interface *intf = cp->interface[i]; 1892 1893 dev_dbg(&dev->dev, 1894 "adding %s (config #%d, interface %d)\n", 1895 dev_name(&intf->dev), configuration, 1896 intf->cur_altsetting->desc.bInterfaceNumber); 1897 device_enable_async_suspend(&intf->dev); 1898 ret = device_add(&intf->dev); 1899 if (ret != 0) { 1900 dev_err(&dev->dev, "device_add(%s) --> %d\n", 1901 dev_name(&intf->dev), ret); 1902 continue; 1903 } 1904 create_intf_ep_devs(intf); 1905 } 1906 1907 usb_autosuspend_device(dev); 1908 return 0; 1909 } 1910 1911 static LIST_HEAD(set_config_list); 1912 static DEFINE_SPINLOCK(set_config_lock); 1913 1914 struct set_config_request { 1915 struct usb_device *udev; 1916 int config; 1917 struct work_struct work; 1918 struct list_head node; 1919 }; 1920 1921 /* Worker routine for usb_driver_set_configuration() */ 1922 static void driver_set_config_work(struct work_struct *work) 1923 { 1924 struct set_config_request *req = 1925 container_of(work, struct set_config_request, work); 1926 struct usb_device *udev = req->udev; 1927 1928 usb_lock_device(udev); 1929 spin_lock(&set_config_lock); 1930 list_del(&req->node); 1931 spin_unlock(&set_config_lock); 1932 1933 if (req->config >= -1) /* Is req still valid? */ 1934 usb_set_configuration(udev, req->config); 1935 usb_unlock_device(udev); 1936 usb_put_dev(udev); 1937 kfree(req); 1938 } 1939 1940 /* Cancel pending Set-Config requests for a device whose configuration 1941 * was just changed 1942 */ 1943 static void cancel_async_set_config(struct usb_device *udev) 1944 { 1945 struct set_config_request *req; 1946 1947 spin_lock(&set_config_lock); 1948 list_for_each_entry(req, &set_config_list, node) { 1949 if (req->udev == udev) 1950 req->config = -999; /* Mark as cancelled */ 1951 } 1952 spin_unlock(&set_config_lock); 1953 } 1954 1955 /** 1956 * usb_driver_set_configuration - Provide a way for drivers to change device configurations 1957 * @udev: the device whose configuration is being updated 1958 * @config: the configuration being chosen. 1959 * Context: In process context, must be able to sleep 1960 * 1961 * Device interface drivers are not allowed to change device configurations. 1962 * This is because changing configurations will destroy the interface the 1963 * driver is bound to and create new ones; it would be like a floppy-disk 1964 * driver telling the computer to replace the floppy-disk drive with a 1965 * tape drive! 1966 * 1967 * Still, in certain specialized circumstances the need may arise. This 1968 * routine gets around the normal restrictions by using a work thread to 1969 * submit the change-config request. 1970 * 1971 * Returns 0 if the request was successfully queued, error code otherwise. 1972 * The caller has no way to know whether the queued request will eventually 1973 * succeed. 1974 */ 1975 int usb_driver_set_configuration(struct usb_device *udev, int config) 1976 { 1977 struct set_config_request *req; 1978 1979 req = kmalloc(sizeof(*req), GFP_KERNEL); 1980 if (!req) 1981 return -ENOMEM; 1982 req->udev = udev; 1983 req->config = config; 1984 INIT_WORK(&req->work, driver_set_config_work); 1985 1986 spin_lock(&set_config_lock); 1987 list_add(&req->node, &set_config_list); 1988 spin_unlock(&set_config_lock); 1989 1990 usb_get_dev(udev); 1991 schedule_work(&req->work); 1992 return 0; 1993 } 1994 EXPORT_SYMBOL_GPL(usb_driver_set_configuration); 1995