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/ioctl.h> 17 #include <linux/slab.h> 18 #include <linux/module.h> 19 #include <linux/mutex.h> 20 #include <linux/uaccess.h> 21 #include <linux/bitops.h> 22 #include <linux/poll.h> 23 #include <linux/usb.h> 24 #include <linux/usb/cdc.h> 25 #include <asm/byteorder.h> 26 #include <asm/unaligned.h> 27 #include <linux/usb/cdc-wdm.h> 28 29 #define DRIVER_AUTHOR "Oliver Neukum" 30 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management" 31 32 static const struct usb_device_id wdm_ids[] = { 33 { 34 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS | 35 USB_DEVICE_ID_MATCH_INT_SUBCLASS, 36 .bInterfaceClass = USB_CLASS_COMM, 37 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM 38 }, 39 { } 40 }; 41 42 MODULE_DEVICE_TABLE (usb, wdm_ids); 43 44 #define WDM_MINOR_BASE 176 45 46 47 #define WDM_IN_USE 1 48 #define WDM_DISCONNECTING 2 49 #define WDM_RESULT 3 50 #define WDM_READ 4 51 #define WDM_INT_STALL 5 52 #define WDM_POLL_RUNNING 6 53 #define WDM_RESPONDING 7 54 #define WDM_SUSPENDING 8 55 #define WDM_RESETTING 9 56 #define WDM_OVERFLOW 10 57 58 #define WDM_MAX 16 59 60 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */ 61 #define WDM_DEFAULT_BUFSIZE 256 62 63 static DEFINE_MUTEX(wdm_mutex); 64 static DEFINE_SPINLOCK(wdm_device_list_lock); 65 static LIST_HEAD(wdm_device_list); 66 67 /* --- method tables --- */ 68 69 struct wdm_device { 70 u8 *inbuf; /* buffer for response */ 71 u8 *outbuf; /* buffer for command */ 72 u8 *sbuf; /* buffer for status */ 73 u8 *ubuf; /* buffer for copy to user space */ 74 75 struct urb *command; 76 struct urb *response; 77 struct urb *validity; 78 struct usb_interface *intf; 79 struct usb_ctrlrequest *orq; 80 struct usb_ctrlrequest *irq; 81 spinlock_t iuspin; 82 83 unsigned long flags; 84 u16 bufsize; 85 u16 wMaxCommand; 86 u16 wMaxPacketSize; 87 __le16 inum; 88 int reslength; 89 int length; 90 int read; 91 int count; 92 dma_addr_t shandle; 93 dma_addr_t ihandle; 94 struct mutex wlock; 95 struct mutex rlock; 96 wait_queue_head_t wait; 97 struct work_struct rxwork; 98 int werr; 99 int rerr; 100 int resp_count; 101 102 struct list_head device_list; 103 int (*manage_power)(struct usb_interface *, int); 104 }; 105 106 static struct usb_driver wdm_driver; 107 108 /* return intfdata if we own the interface, else look up intf in the list */ 109 static struct wdm_device *wdm_find_device(struct usb_interface *intf) 110 { 111 struct wdm_device *desc; 112 113 spin_lock(&wdm_device_list_lock); 114 list_for_each_entry(desc, &wdm_device_list, device_list) 115 if (desc->intf == intf) 116 goto found; 117 desc = NULL; 118 found: 119 spin_unlock(&wdm_device_list_lock); 120 121 return desc; 122 } 123 124 static struct wdm_device *wdm_find_device_by_minor(int minor) 125 { 126 struct wdm_device *desc; 127 128 spin_lock(&wdm_device_list_lock); 129 list_for_each_entry(desc, &wdm_device_list, device_list) 130 if (desc->intf->minor == minor) 131 goto found; 132 desc = NULL; 133 found: 134 spin_unlock(&wdm_device_list_lock); 135 136 return desc; 137 } 138 139 /* --- callbacks --- */ 140 static void wdm_out_callback(struct urb *urb) 141 { 142 struct wdm_device *desc; 143 desc = urb->context; 144 spin_lock(&desc->iuspin); 145 desc->werr = urb->status; 146 spin_unlock(&desc->iuspin); 147 kfree(desc->outbuf); 148 desc->outbuf = NULL; 149 clear_bit(WDM_IN_USE, &desc->flags); 150 wake_up(&desc->wait); 151 } 152 153 /* forward declaration */ 154 static int service_outstanding_interrupt(struct wdm_device *desc); 155 156 static void wdm_in_callback(struct urb *urb) 157 { 158 struct wdm_device *desc = urb->context; 159 int status = urb->status; 160 int length = urb->actual_length; 161 162 spin_lock(&desc->iuspin); 163 clear_bit(WDM_RESPONDING, &desc->flags); 164 165 if (status) { 166 switch (status) { 167 case -ENOENT: 168 dev_dbg(&desc->intf->dev, 169 "nonzero urb status received: -ENOENT\n"); 170 goto skip_error; 171 case -ECONNRESET: 172 dev_dbg(&desc->intf->dev, 173 "nonzero urb status received: -ECONNRESET\n"); 174 goto skip_error; 175 case -ESHUTDOWN: 176 dev_dbg(&desc->intf->dev, 177 "nonzero urb status received: -ESHUTDOWN\n"); 178 goto skip_error; 179 case -EPIPE: 180 dev_err(&desc->intf->dev, 181 "nonzero urb status received: -EPIPE\n"); 182 break; 183 default: 184 dev_err(&desc->intf->dev, 185 "Unexpected error %d\n", status); 186 break; 187 } 188 } 189 190 /* 191 * only set a new error if there is no previous error. 192 * Errors are only cleared during read/open 193 * Avoid propagating -EPIPE (stall) to userspace since it is 194 * better handled as an empty read 195 */ 196 if (desc->rerr == 0 && status != -EPIPE) 197 desc->rerr = status; 198 199 if (length + desc->length > desc->wMaxCommand) { 200 /* The buffer would overflow */ 201 set_bit(WDM_OVERFLOW, &desc->flags); 202 } else { 203 /* we may already be in overflow */ 204 if (!test_bit(WDM_OVERFLOW, &desc->flags)) { 205 memmove(desc->ubuf + desc->length, desc->inbuf, length); 206 desc->length += length; 207 desc->reslength = length; 208 } 209 } 210 skip_error: 211 set_bit(WDM_READ, &desc->flags); 212 wake_up(&desc->wait); 213 214 if (desc->rerr) { 215 /* 216 * Since there was an error, userspace may decide to not read 217 * any data after poll'ing. 218 * We should respond to further attempts from the device to send 219 * data, so that we can get unstuck. 220 */ 221 service_outstanding_interrupt(desc); 222 } 223 224 spin_unlock(&desc->iuspin); 225 } 226 227 static void wdm_int_callback(struct urb *urb) 228 { 229 int rv = 0; 230 int responding; 231 int status = urb->status; 232 struct wdm_device *desc; 233 struct usb_cdc_notification *dr; 234 235 desc = urb->context; 236 dr = (struct usb_cdc_notification *)desc->sbuf; 237 238 if (status) { 239 switch (status) { 240 case -ESHUTDOWN: 241 case -ENOENT: 242 case -ECONNRESET: 243 return; /* unplug */ 244 case -EPIPE: 245 set_bit(WDM_INT_STALL, &desc->flags); 246 dev_err(&desc->intf->dev, "Stall on int endpoint\n"); 247 goto sw; /* halt is cleared in work */ 248 default: 249 dev_err(&desc->intf->dev, 250 "nonzero urb status received: %d\n", status); 251 break; 252 } 253 } 254 255 if (urb->actual_length < sizeof(struct usb_cdc_notification)) { 256 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n", 257 urb->actual_length); 258 goto exit; 259 } 260 261 switch (dr->bNotificationType) { 262 case USB_CDC_NOTIFY_RESPONSE_AVAILABLE: 263 dev_dbg(&desc->intf->dev, 264 "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d\n", 265 le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength)); 266 break; 267 268 case USB_CDC_NOTIFY_NETWORK_CONNECTION: 269 270 dev_dbg(&desc->intf->dev, 271 "NOTIFY_NETWORK_CONNECTION %s network\n", 272 dr->wValue ? "connected to" : "disconnected from"); 273 goto exit; 274 case USB_CDC_NOTIFY_SPEED_CHANGE: 275 dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)\n", 276 urb->actual_length); 277 goto exit; 278 default: 279 clear_bit(WDM_POLL_RUNNING, &desc->flags); 280 dev_err(&desc->intf->dev, 281 "unknown notification %d received: index %d len %d\n", 282 dr->bNotificationType, 283 le16_to_cpu(dr->wIndex), 284 le16_to_cpu(dr->wLength)); 285 goto exit; 286 } 287 288 spin_lock(&desc->iuspin); 289 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags); 290 if (!desc->resp_count++ && !responding 291 && !test_bit(WDM_DISCONNECTING, &desc->flags) 292 && !test_bit(WDM_SUSPENDING, &desc->flags)) { 293 rv = usb_submit_urb(desc->response, GFP_ATOMIC); 294 dev_dbg(&desc->intf->dev, "submit response URB %d\n", rv); 295 } 296 spin_unlock(&desc->iuspin); 297 if (rv < 0) { 298 clear_bit(WDM_RESPONDING, &desc->flags); 299 if (rv == -EPERM) 300 return; 301 if (rv == -ENOMEM) { 302 sw: 303 rv = schedule_work(&desc->rxwork); 304 if (rv) 305 dev_err(&desc->intf->dev, 306 "Cannot schedule work\n"); 307 } 308 } 309 exit: 310 rv = usb_submit_urb(urb, GFP_ATOMIC); 311 if (rv) 312 dev_err(&desc->intf->dev, 313 "%s - usb_submit_urb failed with result %d\n", 314 __func__, rv); 315 316 } 317 318 static void kill_urbs(struct wdm_device *desc) 319 { 320 /* the order here is essential */ 321 usb_kill_urb(desc->command); 322 usb_kill_urb(desc->validity); 323 usb_kill_urb(desc->response); 324 } 325 326 static void free_urbs(struct wdm_device *desc) 327 { 328 usb_free_urb(desc->validity); 329 usb_free_urb(desc->response); 330 usb_free_urb(desc->command); 331 } 332 333 static void cleanup(struct wdm_device *desc) 334 { 335 kfree(desc->sbuf); 336 kfree(desc->inbuf); 337 kfree(desc->orq); 338 kfree(desc->irq); 339 kfree(desc->ubuf); 340 free_urbs(desc); 341 kfree(desc); 342 } 343 344 static ssize_t wdm_write 345 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos) 346 { 347 u8 *buf; 348 int rv = -EMSGSIZE, r, we; 349 struct wdm_device *desc = file->private_data; 350 struct usb_ctrlrequest *req; 351 352 if (count > desc->wMaxCommand) 353 count = desc->wMaxCommand; 354 355 spin_lock_irq(&desc->iuspin); 356 we = desc->werr; 357 desc->werr = 0; 358 spin_unlock_irq(&desc->iuspin); 359 if (we < 0) 360 return usb_translate_errors(we); 361 362 buf = memdup_user(buffer, count); 363 if (IS_ERR(buf)) 364 return PTR_ERR(buf); 365 366 /* concurrent writes and disconnect */ 367 r = mutex_lock_interruptible(&desc->wlock); 368 rv = -ERESTARTSYS; 369 if (r) 370 goto out_free_mem; 371 372 if (test_bit(WDM_DISCONNECTING, &desc->flags)) { 373 rv = -ENODEV; 374 goto out_free_mem_lock; 375 } 376 377 r = usb_autopm_get_interface(desc->intf); 378 if (r < 0) { 379 rv = usb_translate_errors(r); 380 goto out_free_mem_lock; 381 } 382 383 if (!(file->f_flags & O_NONBLOCK)) 384 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE, 385 &desc->flags)); 386 else 387 if (test_bit(WDM_IN_USE, &desc->flags)) 388 r = -EAGAIN; 389 390 if (test_bit(WDM_RESETTING, &desc->flags)) 391 r = -EIO; 392 393 if (r < 0) { 394 rv = r; 395 goto out_free_mem_pm; 396 } 397 398 req = desc->orq; 399 usb_fill_control_urb( 400 desc->command, 401 interface_to_usbdev(desc->intf), 402 /* using common endpoint 0 */ 403 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0), 404 (unsigned char *)req, 405 buf, 406 count, 407 wdm_out_callback, 408 desc 409 ); 410 411 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS | 412 USB_RECIP_INTERFACE); 413 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND; 414 req->wValue = 0; 415 req->wIndex = desc->inum; /* already converted */ 416 req->wLength = cpu_to_le16(count); 417 set_bit(WDM_IN_USE, &desc->flags); 418 desc->outbuf = buf; 419 420 rv = usb_submit_urb(desc->command, GFP_KERNEL); 421 if (rv < 0) { 422 desc->outbuf = NULL; 423 clear_bit(WDM_IN_USE, &desc->flags); 424 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv); 425 rv = usb_translate_errors(rv); 426 goto out_free_mem_pm; 427 } else { 428 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d\n", 429 le16_to_cpu(req->wIndex)); 430 } 431 432 usb_autopm_put_interface(desc->intf); 433 mutex_unlock(&desc->wlock); 434 return count; 435 436 out_free_mem_pm: 437 usb_autopm_put_interface(desc->intf); 438 out_free_mem_lock: 439 mutex_unlock(&desc->wlock); 440 out_free_mem: 441 kfree(buf); 442 return rv; 443 } 444 445 /* 446 * Submit the read urb if resp_count is non-zero. 447 * 448 * Called with desc->iuspin locked 449 */ 450 static int service_outstanding_interrupt(struct wdm_device *desc) 451 { 452 int rv = 0; 453 454 /* submit read urb only if the device is waiting for it */ 455 if (!desc->resp_count || !--desc->resp_count) 456 goto out; 457 458 set_bit(WDM_RESPONDING, &desc->flags); 459 spin_unlock_irq(&desc->iuspin); 460 rv = usb_submit_urb(desc->response, GFP_KERNEL); 461 spin_lock_irq(&desc->iuspin); 462 if (rv) { 463 dev_err(&desc->intf->dev, 464 "usb_submit_urb failed with result %d\n", rv); 465 466 /* make sure the next notification trigger a submit */ 467 clear_bit(WDM_RESPONDING, &desc->flags); 468 desc->resp_count = 0; 469 } 470 out: 471 return rv; 472 } 473 474 static ssize_t wdm_read 475 (struct file *file, char __user *buffer, size_t count, loff_t *ppos) 476 { 477 int rv, cntr; 478 int i = 0; 479 struct wdm_device *desc = file->private_data; 480 481 482 rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */ 483 if (rv < 0) 484 return -ERESTARTSYS; 485 486 cntr = ACCESS_ONCE(desc->length); 487 if (cntr == 0) { 488 desc->read = 0; 489 retry: 490 if (test_bit(WDM_DISCONNECTING, &desc->flags)) { 491 rv = -ENODEV; 492 goto err; 493 } 494 if (test_bit(WDM_OVERFLOW, &desc->flags)) { 495 clear_bit(WDM_OVERFLOW, &desc->flags); 496 rv = -ENOBUFS; 497 goto err; 498 } 499 i++; 500 if (file->f_flags & O_NONBLOCK) { 501 if (!test_bit(WDM_READ, &desc->flags)) { 502 rv = -EAGAIN; 503 goto err; 504 } 505 rv = 0; 506 } else { 507 rv = wait_event_interruptible(desc->wait, 508 test_bit(WDM_READ, &desc->flags)); 509 } 510 511 /* may have happened while we slept */ 512 if (test_bit(WDM_DISCONNECTING, &desc->flags)) { 513 rv = -ENODEV; 514 goto err; 515 } 516 if (test_bit(WDM_RESETTING, &desc->flags)) { 517 rv = -EIO; 518 goto err; 519 } 520 usb_mark_last_busy(interface_to_usbdev(desc->intf)); 521 if (rv < 0) { 522 rv = -ERESTARTSYS; 523 goto err; 524 } 525 526 spin_lock_irq(&desc->iuspin); 527 528 if (desc->rerr) { /* read completed, error happened */ 529 rv = usb_translate_errors(desc->rerr); 530 desc->rerr = 0; 531 spin_unlock_irq(&desc->iuspin); 532 goto err; 533 } 534 /* 535 * recheck whether we've lost the race 536 * against the completion handler 537 */ 538 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */ 539 spin_unlock_irq(&desc->iuspin); 540 goto retry; 541 } 542 543 if (!desc->reslength) { /* zero length read */ 544 dev_dbg(&desc->intf->dev, "zero length - clearing WDM_READ\n"); 545 clear_bit(WDM_READ, &desc->flags); 546 rv = service_outstanding_interrupt(desc); 547 spin_unlock_irq(&desc->iuspin); 548 if (rv < 0) 549 goto err; 550 goto retry; 551 } 552 cntr = desc->length; 553 spin_unlock_irq(&desc->iuspin); 554 } 555 556 if (cntr > count) 557 cntr = count; 558 rv = copy_to_user(buffer, desc->ubuf, cntr); 559 if (rv > 0) { 560 rv = -EFAULT; 561 goto err; 562 } 563 564 spin_lock_irq(&desc->iuspin); 565 566 for (i = 0; i < desc->length - cntr; i++) 567 desc->ubuf[i] = desc->ubuf[i + cntr]; 568 569 desc->length -= cntr; 570 /* in case we had outstanding data */ 571 if (!desc->length) { 572 clear_bit(WDM_READ, &desc->flags); 573 service_outstanding_interrupt(desc); 574 } 575 spin_unlock_irq(&desc->iuspin); 576 rv = cntr; 577 578 err: 579 mutex_unlock(&desc->rlock); 580 return rv; 581 } 582 583 static int wdm_flush(struct file *file, fl_owner_t id) 584 { 585 struct wdm_device *desc = file->private_data; 586 587 wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags)); 588 589 /* cannot dereference desc->intf if WDM_DISCONNECTING */ 590 if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags)) 591 dev_err(&desc->intf->dev, "Error in flush path: %d\n", 592 desc->werr); 593 594 return usb_translate_errors(desc->werr); 595 } 596 597 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait) 598 { 599 struct wdm_device *desc = file->private_data; 600 unsigned long flags; 601 unsigned int mask = 0; 602 603 spin_lock_irqsave(&desc->iuspin, flags); 604 if (test_bit(WDM_DISCONNECTING, &desc->flags)) { 605 mask = POLLHUP | POLLERR; 606 spin_unlock_irqrestore(&desc->iuspin, flags); 607 goto desc_out; 608 } 609 if (test_bit(WDM_READ, &desc->flags)) 610 mask = POLLIN | POLLRDNORM; 611 if (desc->rerr || desc->werr) 612 mask |= POLLERR; 613 if (!test_bit(WDM_IN_USE, &desc->flags)) 614 mask |= POLLOUT | POLLWRNORM; 615 spin_unlock_irqrestore(&desc->iuspin, flags); 616 617 poll_wait(file, &desc->wait, wait); 618 619 desc_out: 620 return mask; 621 } 622 623 static int wdm_open(struct inode *inode, struct file *file) 624 { 625 int minor = iminor(inode); 626 int rv = -ENODEV; 627 struct usb_interface *intf; 628 struct wdm_device *desc; 629 630 mutex_lock(&wdm_mutex); 631 desc = wdm_find_device_by_minor(minor); 632 if (!desc) 633 goto out; 634 635 intf = desc->intf; 636 if (test_bit(WDM_DISCONNECTING, &desc->flags)) 637 goto out; 638 file->private_data = desc; 639 640 rv = usb_autopm_get_interface(desc->intf); 641 if (rv < 0) { 642 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv); 643 goto out; 644 } 645 646 /* using write lock to protect desc->count */ 647 mutex_lock(&desc->wlock); 648 if (!desc->count++) { 649 desc->werr = 0; 650 desc->rerr = 0; 651 rv = usb_submit_urb(desc->validity, GFP_KERNEL); 652 if (rv < 0) { 653 desc->count--; 654 dev_err(&desc->intf->dev, 655 "Error submitting int urb - %d\n", rv); 656 rv = usb_translate_errors(rv); 657 } 658 } else { 659 rv = 0; 660 } 661 mutex_unlock(&desc->wlock); 662 if (desc->count == 1) 663 desc->manage_power(intf, 1); 664 usb_autopm_put_interface(desc->intf); 665 out: 666 mutex_unlock(&wdm_mutex); 667 return rv; 668 } 669 670 static int wdm_release(struct inode *inode, struct file *file) 671 { 672 struct wdm_device *desc = file->private_data; 673 674 mutex_lock(&wdm_mutex); 675 676 /* using write lock to protect desc->count */ 677 mutex_lock(&desc->wlock); 678 desc->count--; 679 mutex_unlock(&desc->wlock); 680 681 if (!desc->count) { 682 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) { 683 dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n"); 684 kill_urbs(desc); 685 spin_lock_irq(&desc->iuspin); 686 desc->resp_count = 0; 687 spin_unlock_irq(&desc->iuspin); 688 desc->manage_power(desc->intf, 0); 689 } else { 690 /* must avoid dev_printk here as desc->intf is invalid */ 691 pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__); 692 cleanup(desc); 693 } 694 } 695 mutex_unlock(&wdm_mutex); 696 return 0; 697 } 698 699 static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 700 { 701 struct wdm_device *desc = file->private_data; 702 int rv = 0; 703 704 switch (cmd) { 705 case IOCTL_WDM_MAX_COMMAND: 706 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand))) 707 rv = -EFAULT; 708 break; 709 default: 710 rv = -ENOTTY; 711 } 712 return rv; 713 } 714 715 static const struct file_operations wdm_fops = { 716 .owner = THIS_MODULE, 717 .read = wdm_read, 718 .write = wdm_write, 719 .open = wdm_open, 720 .flush = wdm_flush, 721 .release = wdm_release, 722 .poll = wdm_poll, 723 .unlocked_ioctl = wdm_ioctl, 724 .compat_ioctl = wdm_ioctl, 725 .llseek = noop_llseek, 726 }; 727 728 static struct usb_class_driver wdm_class = { 729 .name = "cdc-wdm%d", 730 .fops = &wdm_fops, 731 .minor_base = WDM_MINOR_BASE, 732 }; 733 734 /* --- error handling --- */ 735 static void wdm_rxwork(struct work_struct *work) 736 { 737 struct wdm_device *desc = container_of(work, struct wdm_device, rxwork); 738 unsigned long flags; 739 int rv = 0; 740 int responding; 741 742 spin_lock_irqsave(&desc->iuspin, flags); 743 if (test_bit(WDM_DISCONNECTING, &desc->flags)) { 744 spin_unlock_irqrestore(&desc->iuspin, flags); 745 } else { 746 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags); 747 spin_unlock_irqrestore(&desc->iuspin, flags); 748 if (!responding) 749 rv = usb_submit_urb(desc->response, GFP_KERNEL); 750 if (rv < 0 && rv != -EPERM) { 751 spin_lock_irqsave(&desc->iuspin, flags); 752 clear_bit(WDM_RESPONDING, &desc->flags); 753 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) 754 schedule_work(&desc->rxwork); 755 spin_unlock_irqrestore(&desc->iuspin, flags); 756 } 757 } 758 } 759 760 /* --- hotplug --- */ 761 762 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep, 763 u16 bufsize, int (*manage_power)(struct usb_interface *, int)) 764 { 765 int rv = -ENOMEM; 766 struct wdm_device *desc; 767 768 desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL); 769 if (!desc) 770 goto out; 771 INIT_LIST_HEAD(&desc->device_list); 772 mutex_init(&desc->rlock); 773 mutex_init(&desc->wlock); 774 spin_lock_init(&desc->iuspin); 775 init_waitqueue_head(&desc->wait); 776 desc->wMaxCommand = bufsize; 777 /* this will be expanded and needed in hardware endianness */ 778 desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber); 779 desc->intf = intf; 780 INIT_WORK(&desc->rxwork, wdm_rxwork); 781 782 rv = -EINVAL; 783 if (!usb_endpoint_is_int_in(ep)) 784 goto err; 785 786 desc->wMaxPacketSize = usb_endpoint_maxp(ep); 787 788 desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL); 789 if (!desc->orq) 790 goto err; 791 desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL); 792 if (!desc->irq) 793 goto err; 794 795 desc->validity = usb_alloc_urb(0, GFP_KERNEL); 796 if (!desc->validity) 797 goto err; 798 799 desc->response = usb_alloc_urb(0, GFP_KERNEL); 800 if (!desc->response) 801 goto err; 802 803 desc->command = usb_alloc_urb(0, GFP_KERNEL); 804 if (!desc->command) 805 goto err; 806 807 desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL); 808 if (!desc->ubuf) 809 goto err; 810 811 desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL); 812 if (!desc->sbuf) 813 goto err; 814 815 desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL); 816 if (!desc->inbuf) 817 goto err; 818 819 usb_fill_int_urb( 820 desc->validity, 821 interface_to_usbdev(intf), 822 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress), 823 desc->sbuf, 824 desc->wMaxPacketSize, 825 wdm_int_callback, 826 desc, 827 ep->bInterval 828 ); 829 830 desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE); 831 desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE; 832 desc->irq->wValue = 0; 833 desc->irq->wIndex = desc->inum; /* already converted */ 834 desc->irq->wLength = cpu_to_le16(desc->wMaxCommand); 835 836 usb_fill_control_urb( 837 desc->response, 838 interface_to_usbdev(intf), 839 /* using common endpoint 0 */ 840 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0), 841 (unsigned char *)desc->irq, 842 desc->inbuf, 843 desc->wMaxCommand, 844 wdm_in_callback, 845 desc 846 ); 847 848 desc->manage_power = manage_power; 849 850 spin_lock(&wdm_device_list_lock); 851 list_add(&desc->device_list, &wdm_device_list); 852 spin_unlock(&wdm_device_list_lock); 853 854 rv = usb_register_dev(intf, &wdm_class); 855 if (rv < 0) 856 goto err; 857 else 858 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev)); 859 out: 860 return rv; 861 err: 862 spin_lock(&wdm_device_list_lock); 863 list_del(&desc->device_list); 864 spin_unlock(&wdm_device_list_lock); 865 cleanup(desc); 866 return rv; 867 } 868 869 static int wdm_manage_power(struct usb_interface *intf, int on) 870 { 871 /* need autopm_get/put here to ensure the usbcore sees the new value */ 872 int rv = usb_autopm_get_interface(intf); 873 874 intf->needs_remote_wakeup = on; 875 if (!rv) 876 usb_autopm_put_interface(intf); 877 return 0; 878 } 879 880 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id) 881 { 882 int rv = -EINVAL; 883 struct usb_host_interface *iface; 884 struct usb_endpoint_descriptor *ep; 885 struct usb_cdc_parsed_header hdr; 886 u8 *buffer = intf->altsetting->extra; 887 int buflen = intf->altsetting->extralen; 888 u16 maxcom = WDM_DEFAULT_BUFSIZE; 889 890 if (!buffer) 891 goto err; 892 893 cdc_parse_cdc_header(&hdr, intf, buffer, buflen); 894 895 if (hdr.usb_cdc_dmm_desc) 896 maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand); 897 898 iface = intf->cur_altsetting; 899 if (iface->desc.bNumEndpoints != 1) 900 goto err; 901 ep = &iface->endpoint[0].desc; 902 903 rv = wdm_create(intf, ep, maxcom, &wdm_manage_power); 904 905 err: 906 return rv; 907 } 908 909 /** 910 * usb_cdc_wdm_register - register a WDM subdriver 911 * @intf: usb interface the subdriver will associate with 912 * @ep: interrupt endpoint to monitor for notifications 913 * @bufsize: maximum message size to support for read/write 914 * 915 * Create WDM usb class character device and associate it with intf 916 * without binding, allowing another driver to manage the interface. 917 * 918 * The subdriver will manage the given interrupt endpoint exclusively 919 * and will issue control requests referring to the given intf. It 920 * will otherwise avoid interferring, and in particular not do 921 * usb_set_intfdata/usb_get_intfdata on intf. 922 * 923 * The return value is a pointer to the subdriver's struct usb_driver. 924 * The registering driver is responsible for calling this subdriver's 925 * disconnect, suspend, resume, pre_reset and post_reset methods from 926 * its own. 927 */ 928 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf, 929 struct usb_endpoint_descriptor *ep, 930 int bufsize, 931 int (*manage_power)(struct usb_interface *, int)) 932 { 933 int rv = -EINVAL; 934 935 rv = wdm_create(intf, ep, bufsize, manage_power); 936 if (rv < 0) 937 goto err; 938 939 return &wdm_driver; 940 err: 941 return ERR_PTR(rv); 942 } 943 EXPORT_SYMBOL(usb_cdc_wdm_register); 944 945 static void wdm_disconnect(struct usb_interface *intf) 946 { 947 struct wdm_device *desc; 948 unsigned long flags; 949 950 usb_deregister_dev(intf, &wdm_class); 951 desc = wdm_find_device(intf); 952 mutex_lock(&wdm_mutex); 953 954 /* the spinlock makes sure no new urbs are generated in the callbacks */ 955 spin_lock_irqsave(&desc->iuspin, flags); 956 set_bit(WDM_DISCONNECTING, &desc->flags); 957 set_bit(WDM_READ, &desc->flags); 958 /* to terminate pending flushes */ 959 clear_bit(WDM_IN_USE, &desc->flags); 960 spin_unlock_irqrestore(&desc->iuspin, flags); 961 wake_up_all(&desc->wait); 962 mutex_lock(&desc->rlock); 963 mutex_lock(&desc->wlock); 964 kill_urbs(desc); 965 cancel_work_sync(&desc->rxwork); 966 mutex_unlock(&desc->wlock); 967 mutex_unlock(&desc->rlock); 968 969 /* the desc->intf pointer used as list key is now invalid */ 970 spin_lock(&wdm_device_list_lock); 971 list_del(&desc->device_list); 972 spin_unlock(&wdm_device_list_lock); 973 974 if (!desc->count) 975 cleanup(desc); 976 else 977 dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count); 978 mutex_unlock(&wdm_mutex); 979 } 980 981 #ifdef CONFIG_PM 982 static int wdm_suspend(struct usb_interface *intf, pm_message_t message) 983 { 984 struct wdm_device *desc = wdm_find_device(intf); 985 int rv = 0; 986 987 dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor); 988 989 /* if this is an autosuspend the caller does the locking */ 990 if (!PMSG_IS_AUTO(message)) { 991 mutex_lock(&desc->rlock); 992 mutex_lock(&desc->wlock); 993 } 994 spin_lock_irq(&desc->iuspin); 995 996 if (PMSG_IS_AUTO(message) && 997 (test_bit(WDM_IN_USE, &desc->flags) 998 || test_bit(WDM_RESPONDING, &desc->flags))) { 999 spin_unlock_irq(&desc->iuspin); 1000 rv = -EBUSY; 1001 } else { 1002 1003 set_bit(WDM_SUSPENDING, &desc->flags); 1004 spin_unlock_irq(&desc->iuspin); 1005 /* callback submits work - order is essential */ 1006 kill_urbs(desc); 1007 cancel_work_sync(&desc->rxwork); 1008 } 1009 if (!PMSG_IS_AUTO(message)) { 1010 mutex_unlock(&desc->wlock); 1011 mutex_unlock(&desc->rlock); 1012 } 1013 1014 return rv; 1015 } 1016 #endif 1017 1018 static int recover_from_urb_loss(struct wdm_device *desc) 1019 { 1020 int rv = 0; 1021 1022 if (desc->count) { 1023 rv = usb_submit_urb(desc->validity, GFP_NOIO); 1024 if (rv < 0) 1025 dev_err(&desc->intf->dev, 1026 "Error resume submitting int urb - %d\n", rv); 1027 } 1028 return rv; 1029 } 1030 1031 #ifdef CONFIG_PM 1032 static int wdm_resume(struct usb_interface *intf) 1033 { 1034 struct wdm_device *desc = wdm_find_device(intf); 1035 int rv; 1036 1037 dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor); 1038 1039 clear_bit(WDM_SUSPENDING, &desc->flags); 1040 rv = recover_from_urb_loss(desc); 1041 1042 return rv; 1043 } 1044 #endif 1045 1046 static int wdm_pre_reset(struct usb_interface *intf) 1047 { 1048 struct wdm_device *desc = wdm_find_device(intf); 1049 1050 /* 1051 * we notify everybody using poll of 1052 * an exceptional situation 1053 * must be done before recovery lest a spontaneous 1054 * message from the device is lost 1055 */ 1056 spin_lock_irq(&desc->iuspin); 1057 set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */ 1058 set_bit(WDM_READ, &desc->flags); /* unblock read */ 1059 clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */ 1060 desc->rerr = -EINTR; 1061 spin_unlock_irq(&desc->iuspin); 1062 wake_up_all(&desc->wait); 1063 mutex_lock(&desc->rlock); 1064 mutex_lock(&desc->wlock); 1065 kill_urbs(desc); 1066 cancel_work_sync(&desc->rxwork); 1067 return 0; 1068 } 1069 1070 static int wdm_post_reset(struct usb_interface *intf) 1071 { 1072 struct wdm_device *desc = wdm_find_device(intf); 1073 int rv; 1074 1075 clear_bit(WDM_OVERFLOW, &desc->flags); 1076 clear_bit(WDM_RESETTING, &desc->flags); 1077 rv = recover_from_urb_loss(desc); 1078 mutex_unlock(&desc->wlock); 1079 mutex_unlock(&desc->rlock); 1080 return 0; 1081 } 1082 1083 static struct usb_driver wdm_driver = { 1084 .name = "cdc_wdm", 1085 .probe = wdm_probe, 1086 .disconnect = wdm_disconnect, 1087 #ifdef CONFIG_PM 1088 .suspend = wdm_suspend, 1089 .resume = wdm_resume, 1090 .reset_resume = wdm_resume, 1091 #endif 1092 .pre_reset = wdm_pre_reset, 1093 .post_reset = wdm_post_reset, 1094 .id_table = wdm_ids, 1095 .supports_autosuspend = 1, 1096 .disable_hub_initiated_lpm = 1, 1097 }; 1098 1099 module_usb_driver(wdm_driver); 1100 1101 MODULE_AUTHOR(DRIVER_AUTHOR); 1102 MODULE_DESCRIPTION(DRIVER_DESC); 1103 MODULE_LICENSE("GPL"); 1104