1 /* 2 * cdc-wdm.c 3 * 4 * This driver supports USB CDC WCM Device Management. 5 * 6 * Copyright (c) 2007-2009 Oliver Neukum 7 * 8 * Some code taken from cdc-acm.c 9 * 10 * Released under the GPLv2. 11 * 12 * Many thanks to Carl Nordbeck 13 */ 14 #include <linux/kernel.h> 15 #include <linux/errno.h> 16 #include <linux/slab.h> 17 #include <linux/module.h> 18 #include <linux/mutex.h> 19 #include <linux/uaccess.h> 20 #include <linux/bitops.h> 21 #include <linux/poll.h> 22 #include <linux/usb.h> 23 #include <linux/usb/cdc.h> 24 #include <asm/byteorder.h> 25 #include <asm/unaligned.h> 26 #include <linux/usb/cdc-wdm.h> 27 28 /* 29 * Version Information 30 */ 31 #define DRIVER_VERSION "v0.03" 32 #define DRIVER_AUTHOR "Oliver Neukum" 33 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management" 34 35 static const struct usb_device_id wdm_ids[] = { 36 { 37 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS | 38 USB_DEVICE_ID_MATCH_INT_SUBCLASS, 39 .bInterfaceClass = USB_CLASS_COMM, 40 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM 41 }, 42 { } 43 }; 44 45 MODULE_DEVICE_TABLE (usb, wdm_ids); 46 47 #define WDM_MINOR_BASE 176 48 49 50 #define WDM_IN_USE 1 51 #define WDM_DISCONNECTING 2 52 #define WDM_RESULT 3 53 #define WDM_READ 4 54 #define WDM_INT_STALL 5 55 #define WDM_POLL_RUNNING 6 56 #define WDM_RESPONDING 7 57 #define WDM_SUSPENDING 8 58 #define WDM_RESETTING 9 59 #define WDM_OVERFLOW 10 60 61 #define WDM_MAX 16 62 63 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */ 64 #define WDM_DEFAULT_BUFSIZE 256 65 66 static DEFINE_MUTEX(wdm_mutex); 67 static DEFINE_SPINLOCK(wdm_device_list_lock); 68 static LIST_HEAD(wdm_device_list); 69 70 /* --- method tables --- */ 71 72 struct wdm_device { 73 u8 *inbuf; /* buffer for response */ 74 u8 *outbuf; /* buffer for command */ 75 u8 *sbuf; /* buffer for status */ 76 u8 *ubuf; /* buffer for copy to user space */ 77 78 struct urb *command; 79 struct urb *response; 80 struct urb *validity; 81 struct usb_interface *intf; 82 struct usb_ctrlrequest *orq; 83 struct usb_ctrlrequest *irq; 84 spinlock_t iuspin; 85 86 unsigned long flags; 87 u16 bufsize; 88 u16 wMaxCommand; 89 u16 wMaxPacketSize; 90 __le16 inum; 91 int reslength; 92 int length; 93 int read; 94 int count; 95 dma_addr_t shandle; 96 dma_addr_t ihandle; 97 struct mutex wlock; 98 struct mutex rlock; 99 wait_queue_head_t wait; 100 struct work_struct rxwork; 101 int werr; 102 int rerr; 103 104 struct list_head device_list; 105 int (*manage_power)(struct usb_interface *, int); 106 }; 107 108 static struct usb_driver wdm_driver; 109 110 /* return intfdata if we own the interface, else look up intf in the list */ 111 static struct wdm_device *wdm_find_device(struct usb_interface *intf) 112 { 113 struct wdm_device *desc; 114 115 spin_lock(&wdm_device_list_lock); 116 list_for_each_entry(desc, &wdm_device_list, device_list) 117 if (desc->intf == intf) 118 goto found; 119 desc = NULL; 120 found: 121 spin_unlock(&wdm_device_list_lock); 122 123 return desc; 124 } 125 126 static struct wdm_device *wdm_find_device_by_minor(int minor) 127 { 128 struct wdm_device *desc; 129 130 spin_lock(&wdm_device_list_lock); 131 list_for_each_entry(desc, &wdm_device_list, device_list) 132 if (desc->intf->minor == minor) 133 goto found; 134 desc = NULL; 135 found: 136 spin_unlock(&wdm_device_list_lock); 137 138 return desc; 139 } 140 141 /* --- callbacks --- */ 142 static void wdm_out_callback(struct urb *urb) 143 { 144 struct wdm_device *desc; 145 desc = urb->context; 146 spin_lock(&desc->iuspin); 147 desc->werr = urb->status; 148 spin_unlock(&desc->iuspin); 149 kfree(desc->outbuf); 150 desc->outbuf = NULL; 151 clear_bit(WDM_IN_USE, &desc->flags); 152 wake_up(&desc->wait); 153 } 154 155 static void wdm_in_callback(struct urb *urb) 156 { 157 struct wdm_device *desc = urb->context; 158 int status = urb->status; 159 int length = urb->actual_length; 160 161 spin_lock(&desc->iuspin); 162 clear_bit(WDM_RESPONDING, &desc->flags); 163 164 if (status) { 165 switch (status) { 166 case -ENOENT: 167 dev_dbg(&desc->intf->dev, 168 "nonzero urb status received: -ENOENT"); 169 goto skip_error; 170 case -ECONNRESET: 171 dev_dbg(&desc->intf->dev, 172 "nonzero urb status received: -ECONNRESET"); 173 goto skip_error; 174 case -ESHUTDOWN: 175 dev_dbg(&desc->intf->dev, 176 "nonzero urb status received: -ESHUTDOWN"); 177 goto skip_error; 178 case -EPIPE: 179 dev_err(&desc->intf->dev, 180 "nonzero urb status received: -EPIPE\n"); 181 break; 182 default: 183 dev_err(&desc->intf->dev, 184 "Unexpected error %d\n", status); 185 break; 186 } 187 } 188 189 desc->rerr = status; 190 if (length + desc->length > desc->wMaxCommand) { 191 /* The buffer would overflow */ 192 set_bit(WDM_OVERFLOW, &desc->flags); 193 } else { 194 /* we may already be in overflow */ 195 if (!test_bit(WDM_OVERFLOW, &desc->flags)) { 196 memmove(desc->ubuf + desc->length, desc->inbuf, length); 197 desc->length += length; 198 desc->reslength = length; 199 } 200 } 201 skip_error: 202 wake_up(&desc->wait); 203 204 set_bit(WDM_READ, &desc->flags); 205 spin_unlock(&desc->iuspin); 206 } 207 208 static void wdm_int_callback(struct urb *urb) 209 { 210 int rv = 0; 211 int status = urb->status; 212 struct wdm_device *desc; 213 struct usb_cdc_notification *dr; 214 215 desc = urb->context; 216 dr = (struct usb_cdc_notification *)desc->sbuf; 217 218 if (status) { 219 switch (status) { 220 case -ESHUTDOWN: 221 case -ENOENT: 222 case -ECONNRESET: 223 return; /* unplug */ 224 case -EPIPE: 225 set_bit(WDM_INT_STALL, &desc->flags); 226 dev_err(&desc->intf->dev, "Stall on int endpoint\n"); 227 goto sw; /* halt is cleared in work */ 228 default: 229 dev_err(&desc->intf->dev, 230 "nonzero urb status received: %d\n", status); 231 break; 232 } 233 } 234 235 if (urb->actual_length < sizeof(struct usb_cdc_notification)) { 236 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n", 237 urb->actual_length); 238 goto exit; 239 } 240 241 switch (dr->bNotificationType) { 242 case USB_CDC_NOTIFY_RESPONSE_AVAILABLE: 243 dev_dbg(&desc->intf->dev, 244 "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d", 245 dr->wIndex, dr->wLength); 246 break; 247 248 case USB_CDC_NOTIFY_NETWORK_CONNECTION: 249 250 dev_dbg(&desc->intf->dev, 251 "NOTIFY_NETWORK_CONNECTION %s network", 252 dr->wValue ? "connected to" : "disconnected from"); 253 goto exit; 254 default: 255 clear_bit(WDM_POLL_RUNNING, &desc->flags); 256 dev_err(&desc->intf->dev, 257 "unknown notification %d received: index %d len %d\n", 258 dr->bNotificationType, dr->wIndex, dr->wLength); 259 goto exit; 260 } 261 262 spin_lock(&desc->iuspin); 263 clear_bit(WDM_READ, &desc->flags); 264 set_bit(WDM_RESPONDING, &desc->flags); 265 if (!test_bit(WDM_DISCONNECTING, &desc->flags) 266 && !test_bit(WDM_SUSPENDING, &desc->flags)) { 267 rv = usb_submit_urb(desc->response, GFP_ATOMIC); 268 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d", 269 __func__, rv); 270 } 271 spin_unlock(&desc->iuspin); 272 if (rv < 0) { 273 clear_bit(WDM_RESPONDING, &desc->flags); 274 if (rv == -EPERM) 275 return; 276 if (rv == -ENOMEM) { 277 sw: 278 rv = schedule_work(&desc->rxwork); 279 if (rv) 280 dev_err(&desc->intf->dev, 281 "Cannot schedule work\n"); 282 } 283 } 284 exit: 285 rv = usb_submit_urb(urb, GFP_ATOMIC); 286 if (rv) 287 dev_err(&desc->intf->dev, 288 "%s - usb_submit_urb failed with result %d\n", 289 __func__, rv); 290 291 } 292 293 static void kill_urbs(struct wdm_device *desc) 294 { 295 /* the order here is essential */ 296 usb_kill_urb(desc->command); 297 usb_kill_urb(desc->validity); 298 usb_kill_urb(desc->response); 299 } 300 301 static void free_urbs(struct wdm_device *desc) 302 { 303 usb_free_urb(desc->validity); 304 usb_free_urb(desc->response); 305 usb_free_urb(desc->command); 306 } 307 308 static void cleanup(struct wdm_device *desc) 309 { 310 kfree(desc->sbuf); 311 kfree(desc->inbuf); 312 kfree(desc->orq); 313 kfree(desc->irq); 314 kfree(desc->ubuf); 315 free_urbs(desc); 316 kfree(desc); 317 } 318 319 static ssize_t wdm_write 320 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos) 321 { 322 u8 *buf; 323 int rv = -EMSGSIZE, r, we; 324 struct wdm_device *desc = file->private_data; 325 struct usb_ctrlrequest *req; 326 327 if (count > desc->wMaxCommand) 328 count = desc->wMaxCommand; 329 330 spin_lock_irq(&desc->iuspin); 331 we = desc->werr; 332 desc->werr = 0; 333 spin_unlock_irq(&desc->iuspin); 334 if (we < 0) 335 return -EIO; 336 337 buf = kmalloc(count, GFP_KERNEL); 338 if (!buf) { 339 rv = -ENOMEM; 340 goto outnl; 341 } 342 343 r = copy_from_user(buf, buffer, count); 344 if (r > 0) { 345 kfree(buf); 346 rv = -EFAULT; 347 goto outnl; 348 } 349 350 /* concurrent writes and disconnect */ 351 r = mutex_lock_interruptible(&desc->wlock); 352 rv = -ERESTARTSYS; 353 if (r) { 354 kfree(buf); 355 goto outnl; 356 } 357 358 if (test_bit(WDM_DISCONNECTING, &desc->flags)) { 359 kfree(buf); 360 rv = -ENODEV; 361 goto outnp; 362 } 363 364 r = usb_autopm_get_interface(desc->intf); 365 if (r < 0) { 366 kfree(buf); 367 rv = usb_translate_errors(r); 368 goto outnp; 369 } 370 371 if (!(file->f_flags & O_NONBLOCK)) 372 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE, 373 &desc->flags)); 374 else 375 if (test_bit(WDM_IN_USE, &desc->flags)) 376 r = -EAGAIN; 377 378 if (test_bit(WDM_RESETTING, &desc->flags)) 379 r = -EIO; 380 381 if (r < 0) { 382 kfree(buf); 383 rv = r; 384 goto out; 385 } 386 387 req = desc->orq; 388 usb_fill_control_urb( 389 desc->command, 390 interface_to_usbdev(desc->intf), 391 /* using common endpoint 0 */ 392 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0), 393 (unsigned char *)req, 394 buf, 395 count, 396 wdm_out_callback, 397 desc 398 ); 399 400 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS | 401 USB_RECIP_INTERFACE); 402 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND; 403 req->wValue = 0; 404 req->wIndex = desc->inum; 405 req->wLength = cpu_to_le16(count); 406 set_bit(WDM_IN_USE, &desc->flags); 407 desc->outbuf = buf; 408 409 rv = usb_submit_urb(desc->command, GFP_KERNEL); 410 if (rv < 0) { 411 kfree(buf); 412 desc->outbuf = NULL; 413 clear_bit(WDM_IN_USE, &desc->flags); 414 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv); 415 rv = usb_translate_errors(rv); 416 } else { 417 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d", 418 req->wIndex); 419 } 420 out: 421 usb_autopm_put_interface(desc->intf); 422 outnp: 423 mutex_unlock(&desc->wlock); 424 outnl: 425 return rv < 0 ? rv : count; 426 } 427 428 static ssize_t wdm_read 429 (struct file *file, char __user *buffer, size_t count, loff_t *ppos) 430 { 431 int rv, cntr; 432 int i = 0; 433 struct wdm_device *desc = file->private_data; 434 435 436 rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */ 437 if (rv < 0) 438 return -ERESTARTSYS; 439 440 cntr = ACCESS_ONCE(desc->length); 441 if (cntr == 0) { 442 desc->read = 0; 443 retry: 444 if (test_bit(WDM_DISCONNECTING, &desc->flags)) { 445 rv = -ENODEV; 446 goto err; 447 } 448 if (test_bit(WDM_OVERFLOW, &desc->flags)) { 449 clear_bit(WDM_OVERFLOW, &desc->flags); 450 rv = -ENOBUFS; 451 goto err; 452 } 453 i++; 454 if (file->f_flags & O_NONBLOCK) { 455 if (!test_bit(WDM_READ, &desc->flags)) { 456 rv = cntr ? cntr : -EAGAIN; 457 goto err; 458 } 459 rv = 0; 460 } else { 461 rv = wait_event_interruptible(desc->wait, 462 test_bit(WDM_READ, &desc->flags)); 463 } 464 465 /* may have happened while we slept */ 466 if (test_bit(WDM_DISCONNECTING, &desc->flags)) { 467 rv = -ENODEV; 468 goto err; 469 } 470 if (test_bit(WDM_RESETTING, &desc->flags)) { 471 rv = -EIO; 472 goto err; 473 } 474 usb_mark_last_busy(interface_to_usbdev(desc->intf)); 475 if (rv < 0) { 476 rv = -ERESTARTSYS; 477 goto err; 478 } 479 480 spin_lock_irq(&desc->iuspin); 481 482 if (desc->rerr) { /* read completed, error happened */ 483 desc->rerr = 0; 484 spin_unlock_irq(&desc->iuspin); 485 rv = -EIO; 486 goto err; 487 } 488 /* 489 * recheck whether we've lost the race 490 * against the completion handler 491 */ 492 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */ 493 spin_unlock_irq(&desc->iuspin); 494 goto retry; 495 } 496 497 if (!desc->reslength) { /* zero length read */ 498 dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__); 499 clear_bit(WDM_READ, &desc->flags); 500 spin_unlock_irq(&desc->iuspin); 501 goto retry; 502 } 503 cntr = desc->length; 504 spin_unlock_irq(&desc->iuspin); 505 } 506 507 if (cntr > count) 508 cntr = count; 509 rv = copy_to_user(buffer, desc->ubuf, cntr); 510 if (rv > 0) { 511 rv = -EFAULT; 512 goto err; 513 } 514 515 spin_lock_irq(&desc->iuspin); 516 517 for (i = 0; i < desc->length - cntr; i++) 518 desc->ubuf[i] = desc->ubuf[i + cntr]; 519 520 desc->length -= cntr; 521 /* in case we had outstanding data */ 522 if (!desc->length) 523 clear_bit(WDM_READ, &desc->flags); 524 525 spin_unlock_irq(&desc->iuspin); 526 527 rv = cntr; 528 529 err: 530 mutex_unlock(&desc->rlock); 531 return rv; 532 } 533 534 static int wdm_flush(struct file *file, fl_owner_t id) 535 { 536 struct wdm_device *desc = file->private_data; 537 538 wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags)); 539 540 /* cannot dereference desc->intf if WDM_DISCONNECTING */ 541 if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags)) 542 dev_err(&desc->intf->dev, "Error in flush path: %d\n", 543 desc->werr); 544 545 return usb_translate_errors(desc->werr); 546 } 547 548 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait) 549 { 550 struct wdm_device *desc = file->private_data; 551 unsigned long flags; 552 unsigned int mask = 0; 553 554 spin_lock_irqsave(&desc->iuspin, flags); 555 if (test_bit(WDM_DISCONNECTING, &desc->flags)) { 556 mask = POLLHUP | POLLERR; 557 spin_unlock_irqrestore(&desc->iuspin, flags); 558 goto desc_out; 559 } 560 if (test_bit(WDM_READ, &desc->flags)) 561 mask = POLLIN | POLLRDNORM; 562 if (desc->rerr || desc->werr) 563 mask |= POLLERR; 564 if (!test_bit(WDM_IN_USE, &desc->flags)) 565 mask |= POLLOUT | POLLWRNORM; 566 spin_unlock_irqrestore(&desc->iuspin, flags); 567 568 poll_wait(file, &desc->wait, wait); 569 570 desc_out: 571 return mask; 572 } 573 574 static int wdm_open(struct inode *inode, struct file *file) 575 { 576 int minor = iminor(inode); 577 int rv = -ENODEV; 578 struct usb_interface *intf; 579 struct wdm_device *desc; 580 581 mutex_lock(&wdm_mutex); 582 desc = wdm_find_device_by_minor(minor); 583 if (!desc) 584 goto out; 585 586 intf = desc->intf; 587 if (test_bit(WDM_DISCONNECTING, &desc->flags)) 588 goto out; 589 file->private_data = desc; 590 591 rv = usb_autopm_get_interface(desc->intf); 592 if (rv < 0) { 593 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv); 594 goto out; 595 } 596 597 /* using write lock to protect desc->count */ 598 mutex_lock(&desc->wlock); 599 if (!desc->count++) { 600 desc->werr = 0; 601 desc->rerr = 0; 602 rv = usb_submit_urb(desc->validity, GFP_KERNEL); 603 if (rv < 0) { 604 desc->count--; 605 dev_err(&desc->intf->dev, 606 "Error submitting int urb - %d\n", rv); 607 rv = usb_translate_errors(rv); 608 } 609 } else { 610 rv = 0; 611 } 612 mutex_unlock(&desc->wlock); 613 if (desc->count == 1) 614 desc->manage_power(intf, 1); 615 usb_autopm_put_interface(desc->intf); 616 out: 617 mutex_unlock(&wdm_mutex); 618 return rv; 619 } 620 621 static int wdm_release(struct inode *inode, struct file *file) 622 { 623 struct wdm_device *desc = file->private_data; 624 625 mutex_lock(&wdm_mutex); 626 627 /* using write lock to protect desc->count */ 628 mutex_lock(&desc->wlock); 629 desc->count--; 630 mutex_unlock(&desc->wlock); 631 632 if (!desc->count) { 633 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) { 634 dev_dbg(&desc->intf->dev, "wdm_release: cleanup"); 635 kill_urbs(desc); 636 desc->manage_power(desc->intf, 0); 637 } else { 638 /* must avoid dev_printk here as desc->intf is invalid */ 639 pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__); 640 cleanup(desc); 641 } 642 } 643 mutex_unlock(&wdm_mutex); 644 return 0; 645 } 646 647 static const struct file_operations wdm_fops = { 648 .owner = THIS_MODULE, 649 .read = wdm_read, 650 .write = wdm_write, 651 .open = wdm_open, 652 .flush = wdm_flush, 653 .release = wdm_release, 654 .poll = wdm_poll, 655 .llseek = noop_llseek, 656 }; 657 658 static struct usb_class_driver wdm_class = { 659 .name = "cdc-wdm%d", 660 .fops = &wdm_fops, 661 .minor_base = WDM_MINOR_BASE, 662 }; 663 664 /* --- error handling --- */ 665 static void wdm_rxwork(struct work_struct *work) 666 { 667 struct wdm_device *desc = container_of(work, struct wdm_device, rxwork); 668 unsigned long flags; 669 int rv; 670 671 spin_lock_irqsave(&desc->iuspin, flags); 672 if (test_bit(WDM_DISCONNECTING, &desc->flags)) { 673 spin_unlock_irqrestore(&desc->iuspin, flags); 674 } else { 675 spin_unlock_irqrestore(&desc->iuspin, flags); 676 rv = usb_submit_urb(desc->response, GFP_KERNEL); 677 if (rv < 0 && rv != -EPERM) { 678 spin_lock_irqsave(&desc->iuspin, flags); 679 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) 680 schedule_work(&desc->rxwork); 681 spin_unlock_irqrestore(&desc->iuspin, flags); 682 } 683 } 684 } 685 686 /* --- hotplug --- */ 687 688 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep, 689 u16 bufsize, int (*manage_power)(struct usb_interface *, int)) 690 { 691 int rv = -ENOMEM; 692 struct wdm_device *desc; 693 694 desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL); 695 if (!desc) 696 goto out; 697 INIT_LIST_HEAD(&desc->device_list); 698 mutex_init(&desc->rlock); 699 mutex_init(&desc->wlock); 700 spin_lock_init(&desc->iuspin); 701 init_waitqueue_head(&desc->wait); 702 desc->wMaxCommand = bufsize; 703 /* this will be expanded and needed in hardware endianness */ 704 desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber); 705 desc->intf = intf; 706 INIT_WORK(&desc->rxwork, wdm_rxwork); 707 708 rv = -EINVAL; 709 if (!usb_endpoint_is_int_in(ep)) 710 goto err; 711 712 desc->wMaxPacketSize = usb_endpoint_maxp(ep); 713 714 desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL); 715 if (!desc->orq) 716 goto err; 717 desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL); 718 if (!desc->irq) 719 goto err; 720 721 desc->validity = usb_alloc_urb(0, GFP_KERNEL); 722 if (!desc->validity) 723 goto err; 724 725 desc->response = usb_alloc_urb(0, GFP_KERNEL); 726 if (!desc->response) 727 goto err; 728 729 desc->command = usb_alloc_urb(0, GFP_KERNEL); 730 if (!desc->command) 731 goto err; 732 733 desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL); 734 if (!desc->ubuf) 735 goto err; 736 737 desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL); 738 if (!desc->sbuf) 739 goto err; 740 741 desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL); 742 if (!desc->inbuf) 743 goto err; 744 745 usb_fill_int_urb( 746 desc->validity, 747 interface_to_usbdev(intf), 748 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress), 749 desc->sbuf, 750 desc->wMaxPacketSize, 751 wdm_int_callback, 752 desc, 753 ep->bInterval 754 ); 755 756 desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE); 757 desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE; 758 desc->irq->wValue = 0; 759 desc->irq->wIndex = desc->inum; 760 desc->irq->wLength = cpu_to_le16(desc->wMaxCommand); 761 762 usb_fill_control_urb( 763 desc->response, 764 interface_to_usbdev(intf), 765 /* using common endpoint 0 */ 766 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0), 767 (unsigned char *)desc->irq, 768 desc->inbuf, 769 desc->wMaxCommand, 770 wdm_in_callback, 771 desc 772 ); 773 774 desc->manage_power = manage_power; 775 776 spin_lock(&wdm_device_list_lock); 777 list_add(&desc->device_list, &wdm_device_list); 778 spin_unlock(&wdm_device_list_lock); 779 780 rv = usb_register_dev(intf, &wdm_class); 781 if (rv < 0) 782 goto err; 783 else 784 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev)); 785 out: 786 return rv; 787 err: 788 spin_lock(&wdm_device_list_lock); 789 list_del(&desc->device_list); 790 spin_unlock(&wdm_device_list_lock); 791 cleanup(desc); 792 return rv; 793 } 794 795 static int wdm_manage_power(struct usb_interface *intf, int on) 796 { 797 /* need autopm_get/put here to ensure the usbcore sees the new value */ 798 int rv = usb_autopm_get_interface(intf); 799 if (rv < 0) 800 goto err; 801 802 intf->needs_remote_wakeup = on; 803 usb_autopm_put_interface(intf); 804 err: 805 return rv; 806 } 807 808 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id) 809 { 810 int rv = -EINVAL; 811 struct usb_host_interface *iface; 812 struct usb_endpoint_descriptor *ep; 813 struct usb_cdc_dmm_desc *dmhd; 814 u8 *buffer = intf->altsetting->extra; 815 int buflen = intf->altsetting->extralen; 816 u16 maxcom = WDM_DEFAULT_BUFSIZE; 817 818 if (!buffer) 819 goto err; 820 while (buflen > 2) { 821 if (buffer[1] != USB_DT_CS_INTERFACE) { 822 dev_err(&intf->dev, "skipping garbage\n"); 823 goto next_desc; 824 } 825 826 switch (buffer[2]) { 827 case USB_CDC_HEADER_TYPE: 828 break; 829 case USB_CDC_DMM_TYPE: 830 dmhd = (struct usb_cdc_dmm_desc *)buffer; 831 maxcom = le16_to_cpu(dmhd->wMaxCommand); 832 dev_dbg(&intf->dev, 833 "Finding maximum buffer length: %d", maxcom); 834 break; 835 default: 836 dev_err(&intf->dev, 837 "Ignoring extra header, type %d, length %d\n", 838 buffer[2], buffer[0]); 839 break; 840 } 841 next_desc: 842 buflen -= buffer[0]; 843 buffer += buffer[0]; 844 } 845 846 iface = intf->cur_altsetting; 847 if (iface->desc.bNumEndpoints != 1) 848 goto err; 849 ep = &iface->endpoint[0].desc; 850 851 rv = wdm_create(intf, ep, maxcom, &wdm_manage_power); 852 853 err: 854 return rv; 855 } 856 857 /** 858 * usb_cdc_wdm_register - register a WDM subdriver 859 * @intf: usb interface the subdriver will associate with 860 * @ep: interrupt endpoint to monitor for notifications 861 * @bufsize: maximum message size to support for read/write 862 * 863 * Create WDM usb class character device and associate it with intf 864 * without binding, allowing another driver to manage the interface. 865 * 866 * The subdriver will manage the given interrupt endpoint exclusively 867 * and will issue control requests referring to the given intf. It 868 * will otherwise avoid interferring, and in particular not do 869 * usb_set_intfdata/usb_get_intfdata on intf. 870 * 871 * The return value is a pointer to the subdriver's struct usb_driver. 872 * The registering driver is responsible for calling this subdriver's 873 * disconnect, suspend, resume, pre_reset and post_reset methods from 874 * its own. 875 */ 876 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf, 877 struct usb_endpoint_descriptor *ep, 878 int bufsize, 879 int (*manage_power)(struct usb_interface *, int)) 880 { 881 int rv = -EINVAL; 882 883 rv = wdm_create(intf, ep, bufsize, manage_power); 884 if (rv < 0) 885 goto err; 886 887 return &wdm_driver; 888 err: 889 return ERR_PTR(rv); 890 } 891 EXPORT_SYMBOL(usb_cdc_wdm_register); 892 893 static void wdm_disconnect(struct usb_interface *intf) 894 { 895 struct wdm_device *desc; 896 unsigned long flags; 897 898 usb_deregister_dev(intf, &wdm_class); 899 desc = wdm_find_device(intf); 900 mutex_lock(&wdm_mutex); 901 902 /* the spinlock makes sure no new urbs are generated in the callbacks */ 903 spin_lock_irqsave(&desc->iuspin, flags); 904 set_bit(WDM_DISCONNECTING, &desc->flags); 905 set_bit(WDM_READ, &desc->flags); 906 /* to terminate pending flushes */ 907 clear_bit(WDM_IN_USE, &desc->flags); 908 spin_unlock_irqrestore(&desc->iuspin, flags); 909 wake_up_all(&desc->wait); 910 mutex_lock(&desc->rlock); 911 mutex_lock(&desc->wlock); 912 kill_urbs(desc); 913 cancel_work_sync(&desc->rxwork); 914 mutex_unlock(&desc->wlock); 915 mutex_unlock(&desc->rlock); 916 917 /* the desc->intf pointer used as list key is now invalid */ 918 spin_lock(&wdm_device_list_lock); 919 list_del(&desc->device_list); 920 spin_unlock(&wdm_device_list_lock); 921 922 if (!desc->count) 923 cleanup(desc); 924 else 925 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count); 926 mutex_unlock(&wdm_mutex); 927 } 928 929 #ifdef CONFIG_PM 930 static int wdm_suspend(struct usb_interface *intf, pm_message_t message) 931 { 932 struct wdm_device *desc = wdm_find_device(intf); 933 int rv = 0; 934 935 dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor); 936 937 /* if this is an autosuspend the caller does the locking */ 938 if (!PMSG_IS_AUTO(message)) { 939 mutex_lock(&desc->rlock); 940 mutex_lock(&desc->wlock); 941 } 942 spin_lock_irq(&desc->iuspin); 943 944 if (PMSG_IS_AUTO(message) && 945 (test_bit(WDM_IN_USE, &desc->flags) 946 || test_bit(WDM_RESPONDING, &desc->flags))) { 947 spin_unlock_irq(&desc->iuspin); 948 rv = -EBUSY; 949 } else { 950 951 set_bit(WDM_SUSPENDING, &desc->flags); 952 spin_unlock_irq(&desc->iuspin); 953 /* callback submits work - order is essential */ 954 kill_urbs(desc); 955 cancel_work_sync(&desc->rxwork); 956 } 957 if (!PMSG_IS_AUTO(message)) { 958 mutex_unlock(&desc->wlock); 959 mutex_unlock(&desc->rlock); 960 } 961 962 return rv; 963 } 964 #endif 965 966 static int recover_from_urb_loss(struct wdm_device *desc) 967 { 968 int rv = 0; 969 970 if (desc->count) { 971 rv = usb_submit_urb(desc->validity, GFP_NOIO); 972 if (rv < 0) 973 dev_err(&desc->intf->dev, 974 "Error resume submitting int urb - %d\n", rv); 975 } 976 return rv; 977 } 978 979 #ifdef CONFIG_PM 980 static int wdm_resume(struct usb_interface *intf) 981 { 982 struct wdm_device *desc = wdm_find_device(intf); 983 int rv; 984 985 dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor); 986 987 clear_bit(WDM_SUSPENDING, &desc->flags); 988 rv = recover_from_urb_loss(desc); 989 990 return rv; 991 } 992 #endif 993 994 static int wdm_pre_reset(struct usb_interface *intf) 995 { 996 struct wdm_device *desc = wdm_find_device(intf); 997 998 /* 999 * we notify everybody using poll of 1000 * an exceptional situation 1001 * must be done before recovery lest a spontaneous 1002 * message from the device is lost 1003 */ 1004 spin_lock_irq(&desc->iuspin); 1005 set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */ 1006 set_bit(WDM_READ, &desc->flags); /* unblock read */ 1007 clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */ 1008 desc->rerr = -EINTR; 1009 spin_unlock_irq(&desc->iuspin); 1010 wake_up_all(&desc->wait); 1011 mutex_lock(&desc->rlock); 1012 mutex_lock(&desc->wlock); 1013 kill_urbs(desc); 1014 cancel_work_sync(&desc->rxwork); 1015 return 0; 1016 } 1017 1018 static int wdm_post_reset(struct usb_interface *intf) 1019 { 1020 struct wdm_device *desc = wdm_find_device(intf); 1021 int rv; 1022 1023 clear_bit(WDM_OVERFLOW, &desc->flags); 1024 clear_bit(WDM_RESETTING, &desc->flags); 1025 rv = recover_from_urb_loss(desc); 1026 mutex_unlock(&desc->wlock); 1027 mutex_unlock(&desc->rlock); 1028 return 0; 1029 } 1030 1031 static struct usb_driver wdm_driver = { 1032 .name = "cdc_wdm", 1033 .probe = wdm_probe, 1034 .disconnect = wdm_disconnect, 1035 #ifdef CONFIG_PM 1036 .suspend = wdm_suspend, 1037 .resume = wdm_resume, 1038 .reset_resume = wdm_resume, 1039 #endif 1040 .pre_reset = wdm_pre_reset, 1041 .post_reset = wdm_post_reset, 1042 .id_table = wdm_ids, 1043 .supports_autosuspend = 1, 1044 .disable_hub_initiated_lpm = 1, 1045 }; 1046 1047 module_usb_driver(wdm_driver); 1048 1049 MODULE_AUTHOR(DRIVER_AUTHOR); 1050 MODULE_DESCRIPTION(DRIVER_DESC); 1051 MODULE_LICENSE("GPL"); 1052