1// SPDX-License-Identifier: GPL-2.0
2/*
3 * cdc-wdm.c
4 *
5 * This driver supports USB CDC WCM Device Management.
6 *
7 * Copyright (c) 2007-2009 Oliver Neukum
8 *
9 * Some code taken from cdc-acm.c
10 *
11 * Released under the GPLv2.
12 *
13 * Many thanks to Carl Nordbeck
14 */
15#include <linux/kernel.h>
16#include <linux/errno.h>
17#include <linux/ioctl.h>
18#include <linux/slab.h>
19#include <linux/module.h>
20#include <linux/mutex.h>
21#include <linux/uaccess.h>
22#include <linux/bitops.h>
23#include <linux/poll.h>
24#include <linux/skbuff.h>
25#include <linux/usb.h>
26#include <linux/usb/cdc.h>
27#include <linux/wwan.h>
28#include <asm/byteorder.h>
29#include <linux/unaligned.h>
30#include <linux/usb/cdc-wdm.h>
31
32#define DRIVER_AUTHOR "Oliver Neukum"
33#define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
34
35static 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
45MODULE_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#define WDM_WWAN_IN_USE 11
61
62#define WDM_MAX 16
63
64/* we cannot wait forever at flush() */
65#define WDM_FLUSH_TIMEOUT (30 * HZ)
66
67/* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
68#define WDM_DEFAULT_BUFSIZE 256
69
70static DEFINE_MUTEX(wdm_mutex);
71static DEFINE_SPINLOCK(wdm_device_list_lock);
72static LIST_HEAD(wdm_device_list);
73
74/* --- method tables --- */
75
76struct wdm_device {
77 u8 *inbuf; /* buffer for response */
78 u8 *outbuf; /* buffer for command */
79 u8 *sbuf; /* buffer for status */
80 u8 *ubuf; /* buffer for copy to user space */
81
82 struct urb *command;
83 struct urb *response;
84 struct urb *validity;
85 struct usb_interface *intf;
86 struct usb_ctrlrequest *orq;
87 struct usb_ctrlrequest *irq;
88 spinlock_t iuspin;
89
90 unsigned long flags;
91 u16 bufsize;
92 u16 wMaxCommand;
93 u16 wMaxPacketSize;
94 __le16 inum;
95 int length;
96 int read;
97 int count;
98 dma_addr_t shandle;
99 dma_addr_t ihandle;
100 struct mutex wlock;
101 struct mutex rlock;
102 wait_queue_head_t wait;
103 struct work_struct rxwork;
104 struct work_struct service_outs_intr;
105 int werr;
106 int rerr;
107 int resp_count;
108
109 struct list_head device_list;
110 int (*manage_power)(struct usb_interface *, int);
111
112 enum wwan_port_type wwanp_type;
113 struct wwan_port *wwanp;
114};
115
116static struct usb_driver wdm_driver;
117
118/* return intfdata if we own the interface, else look up intf in the list */
119static struct wdm_device *wdm_find_device(struct usb_interface *intf)
120{
121 struct wdm_device *desc;
122
123 spin_lock(lock: &wdm_device_list_lock);
124 list_for_each_entry(desc, &wdm_device_list, device_list)
125 if (desc->intf == intf)
126 goto found;
127 desc = NULL;
128found:
129 spin_unlock(lock: &wdm_device_list_lock);
130
131 return desc;
132}
133
134static struct wdm_device *wdm_find_device_by_minor(int minor)
135{
136 struct wdm_device *desc;
137
138 spin_lock(lock: &wdm_device_list_lock);
139 list_for_each_entry(desc, &wdm_device_list, device_list)
140 if (desc->intf->minor == minor)
141 goto found;
142 desc = NULL;
143found:
144 spin_unlock(lock: &wdm_device_list_lock);
145
146 return desc;
147}
148
149/* --- callbacks --- */
150static void wdm_out_callback(struct urb *urb)
151{
152 struct wdm_device *desc;
153 unsigned long flags;
154
155 desc = urb->context;
156 spin_lock_irqsave(&desc->iuspin, flags);
157 desc->werr = urb->status;
158 spin_unlock_irqrestore(lock: &desc->iuspin, flags);
159 kfree(objp: desc->outbuf);
160 desc->outbuf = NULL;
161 clear_bit(WDM_IN_USE, addr: &desc->flags);
162 wake_up_all(&desc->wait);
163}
164
165static void wdm_wwan_rx(struct wdm_device *desc, int length);
166
167static void wdm_in_callback(struct urb *urb)
168{
169 unsigned long flags;
170 struct wdm_device *desc = urb->context;
171 int status = urb->status;
172 int length = urb->actual_length;
173
174 spin_lock_irqsave(&desc->iuspin, flags);
175 clear_bit(WDM_RESPONDING, addr: &desc->flags);
176
177 if (status) {
178 switch (status) {
179 case -ENOENT:
180 dev_dbg(&desc->intf->dev,
181 "nonzero urb status received: -ENOENT\n");
182 goto skip_error;
183 case -ECONNRESET:
184 dev_dbg(&desc->intf->dev,
185 "nonzero urb status received: -ECONNRESET\n");
186 goto skip_error;
187 case -ESHUTDOWN:
188 dev_dbg(&desc->intf->dev,
189 "nonzero urb status received: -ESHUTDOWN\n");
190 goto skip_error;
191 case -EPIPE:
192 dev_err(&desc->intf->dev,
193 "nonzero urb status received: -EPIPE\n");
194 break;
195 default:
196 dev_err(&desc->intf->dev,
197 "Unexpected error %d\n", status);
198 break;
199 }
200 }
201
202 if (test_bit(WDM_WWAN_IN_USE, &desc->flags)) {
203 wdm_wwan_rx(desc, length);
204 goto out;
205 }
206
207 /*
208 * only set a new error if there is no previous error.
209 * Errors are only cleared during read/open
210 * Avoid propagating -EPIPE (stall) to userspace since it is
211 * better handled as an empty read
212 */
213 if (desc->rerr == 0 && status != -EPIPE)
214 desc->rerr = status;
215
216 if (length == 0) {
217 dev_dbg(&desc->intf->dev, "received ZLP\n");
218 goto skip_zlp;
219 }
220
221 if (length + desc->length > desc->wMaxCommand) {
222 /* The buffer would overflow */
223 set_bit(WDM_OVERFLOW, addr: &desc->flags);
224 } else {
225 /* we may already be in overflow */
226 if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
227 memmove(desc->ubuf + desc->length, desc->inbuf, length);
228 desc->length += length;
229 }
230 }
231skip_error:
232
233 if (desc->rerr) {
234 /*
235 * If there was a ZLP or an error, userspace may decide to not
236 * read any data after poll'ing.
237 * We should respond to further attempts from the device to send
238 * data, so that we can get unstuck.
239 */
240skip_zlp:
241 schedule_work(work: &desc->service_outs_intr);
242 } else {
243 set_bit(WDM_READ, addr: &desc->flags);
244 wake_up(&desc->wait);
245 }
246out:
247 spin_unlock_irqrestore(lock: &desc->iuspin, flags);
248}
249
250static void wdm_int_callback(struct urb *urb)
251{
252 unsigned long flags;
253 int rv = 0;
254 int responding;
255 int status = urb->status;
256 struct wdm_device *desc;
257 struct usb_cdc_notification *dr;
258
259 desc = urb->context;
260 dr = (struct usb_cdc_notification *)desc->sbuf;
261
262 if (status) {
263 switch (status) {
264 case -ESHUTDOWN:
265 case -ENOENT:
266 case -ECONNRESET:
267 return; /* unplug */
268 case -EPIPE:
269 set_bit(WDM_INT_STALL, addr: &desc->flags);
270 dev_err(&desc->intf->dev, "Stall on int endpoint\n");
271 goto sw; /* halt is cleared in work */
272 default:
273 dev_err_ratelimited(&desc->intf->dev,
274 "nonzero urb status received: %d\n", status);
275 break;
276 }
277 }
278
279 if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
280 dev_err_ratelimited(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
281 urb->actual_length);
282 goto exit;
283 }
284
285 switch (dr->bNotificationType) {
286 case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
287 dev_dbg(&desc->intf->dev,
288 "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d\n",
289 le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength));
290 break;
291
292 case USB_CDC_NOTIFY_NETWORK_CONNECTION:
293
294 dev_dbg(&desc->intf->dev,
295 "NOTIFY_NETWORK_CONNECTION %s network\n",
296 dr->wValue ? "connected to" : "disconnected from");
297 goto exit;
298 case USB_CDC_NOTIFY_SPEED_CHANGE:
299 dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)\n",
300 urb->actual_length);
301 goto exit;
302 default:
303 clear_bit(WDM_POLL_RUNNING, addr: &desc->flags);
304 dev_err(&desc->intf->dev,
305 "unknown notification %d received: index %d len %d\n",
306 dr->bNotificationType,
307 le16_to_cpu(dr->wIndex),
308 le16_to_cpu(dr->wLength));
309 goto exit;
310 }
311
312 spin_lock_irqsave(&desc->iuspin, flags);
313 responding = test_and_set_bit(WDM_RESPONDING, addr: &desc->flags);
314 if (!desc->resp_count++ && !responding
315 && !test_bit(WDM_DISCONNECTING, &desc->flags)
316 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
317 rv = usb_submit_urb(urb: desc->response, GFP_ATOMIC);
318 dev_dbg(&desc->intf->dev, "submit response URB %d\n", rv);
319 }
320 spin_unlock_irqrestore(lock: &desc->iuspin, flags);
321 if (rv < 0) {
322 clear_bit(WDM_RESPONDING, addr: &desc->flags);
323 if (rv == -EPERM)
324 return;
325 if (rv == -ENOMEM) {
326sw:
327 rv = schedule_work(work: &desc->rxwork);
328 if (rv)
329 dev_err(&desc->intf->dev,
330 "Cannot schedule work\n");
331 }
332 }
333exit:
334 rv = usb_submit_urb(urb, GFP_ATOMIC);
335 if (rv)
336 dev_err(&desc->intf->dev,
337 "%s - usb_submit_urb failed with result %d\n",
338 __func__, rv);
339
340}
341
342static void poison_urbs(struct wdm_device *desc)
343{
344 /* the order here is essential */
345 usb_poison_urb(urb: desc->command);
346 usb_poison_urb(urb: desc->validity);
347 usb_poison_urb(urb: desc->response);
348}
349
350static void unpoison_urbs(struct wdm_device *desc)
351{
352 /*
353 * the order here is not essential
354 * it is symmetrical just to be nice
355 */
356 usb_unpoison_urb(urb: desc->response);
357 usb_unpoison_urb(urb: desc->validity);
358 usb_unpoison_urb(urb: desc->command);
359}
360
361static void free_urbs(struct wdm_device *desc)
362{
363 usb_free_urb(urb: desc->validity);
364 usb_free_urb(urb: desc->response);
365 usb_free_urb(urb: desc->command);
366}
367
368static void cleanup(struct wdm_device *desc)
369{
370 kfree(objp: desc->sbuf);
371 kfree(objp: desc->inbuf);
372 kfree(objp: desc->orq);
373 kfree(objp: desc->irq);
374 kfree(objp: desc->ubuf);
375 free_urbs(desc);
376 kfree(objp: desc);
377}
378
379static ssize_t wdm_write
380(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
381{
382 u8 *buf;
383 int rv = -EMSGSIZE, r, we;
384 struct wdm_device *desc = file->private_data;
385 struct usb_ctrlrequest *req;
386
387 if (count > desc->wMaxCommand)
388 count = desc->wMaxCommand;
389
390 spin_lock_irq(lock: &desc->iuspin);
391 we = desc->werr;
392 desc->werr = 0;
393 spin_unlock_irq(lock: &desc->iuspin);
394 if (we < 0)
395 return usb_translate_errors(error_code: we);
396
397 buf = memdup_user(buffer, count);
398 if (IS_ERR(ptr: buf))
399 return PTR_ERR(ptr: buf);
400
401 /* concurrent writes and disconnect */
402 r = mutex_lock_interruptible(&desc->wlock);
403 rv = -ERESTARTSYS;
404 if (r)
405 goto out_free_mem;
406
407 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
408 rv = -ENODEV;
409 goto out_free_mem_lock;
410 }
411
412 r = usb_autopm_get_interface(intf: desc->intf);
413 if (r < 0) {
414 rv = usb_translate_errors(error_code: r);
415 goto out_free_mem_lock;
416 }
417
418 if (!(file->f_flags & O_NONBLOCK))
419 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
420 &desc->flags));
421 else
422 if (test_bit(WDM_IN_USE, &desc->flags))
423 r = -EAGAIN;
424
425 if (test_bit(WDM_RESETTING, &desc->flags))
426 r = -EIO;
427
428 if (test_bit(WDM_DISCONNECTING, &desc->flags))
429 r = -ENODEV;
430
431 if (r < 0) {
432 rv = r;
433 goto out_free_mem_pm;
434 }
435
436 req = desc->orq;
437 usb_fill_control_urb(
438 urb: desc->command,
439 interface_to_usbdev(desc->intf),
440 /* using common endpoint 0 */
441 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
442 setup_packet: (unsigned char *)req,
443 transfer_buffer: buf,
444 buffer_length: count,
445 complete_fn: wdm_out_callback,
446 context: desc
447 );
448
449 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
450 USB_RECIP_INTERFACE);
451 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
452 req->wValue = 0;
453 req->wIndex = desc->inum; /* already converted */
454 req->wLength = cpu_to_le16(count);
455 set_bit(WDM_IN_USE, addr: &desc->flags);
456 desc->outbuf = buf;
457
458 rv = usb_submit_urb(urb: desc->command, GFP_KERNEL);
459 if (rv < 0) {
460 desc->outbuf = NULL;
461 clear_bit(WDM_IN_USE, addr: &desc->flags);
462 wake_up_all(&desc->wait); /* for wdm_wait_for_response() */
463 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
464 rv = usb_translate_errors(error_code: rv);
465 goto out_free_mem_pm;
466 } else {
467 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d\n",
468 le16_to_cpu(req->wIndex));
469 }
470
471 usb_autopm_put_interface(intf: desc->intf);
472 mutex_unlock(lock: &desc->wlock);
473 return count;
474
475out_free_mem_pm:
476 usb_autopm_put_interface(intf: desc->intf);
477out_free_mem_lock:
478 mutex_unlock(lock: &desc->wlock);
479out_free_mem:
480 kfree(objp: buf);
481 return rv;
482}
483
484/*
485 * Submit the read urb if resp_count is non-zero.
486 *
487 * Called with desc->iuspin locked
488 */
489static int service_outstanding_interrupt(struct wdm_device *desc)
490{
491 int rv = 0;
492
493 /* submit read urb only if the device is waiting for it */
494 if (!desc->resp_count || !--desc->resp_count)
495 goto out;
496
497 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
498 rv = -ENODEV;
499 goto out;
500 }
501 if (test_bit(WDM_RESETTING, &desc->flags)) {
502 rv = -EIO;
503 goto out;
504 }
505
506 set_bit(WDM_RESPONDING, addr: &desc->flags);
507 spin_unlock_irq(lock: &desc->iuspin);
508 rv = usb_submit_urb(urb: desc->response, GFP_KERNEL);
509 spin_lock_irq(lock: &desc->iuspin);
510 if (rv) {
511 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
512 dev_err(&desc->intf->dev,
513 "usb_submit_urb failed with result %d\n", rv);
514
515 /* make sure the next notification trigger a submit */
516 clear_bit(WDM_RESPONDING, addr: &desc->flags);
517 desc->resp_count = 0;
518 }
519out:
520 return rv;
521}
522
523static ssize_t wdm_read
524(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
525{
526 int rv, cntr;
527 int i = 0;
528 struct wdm_device *desc = file->private_data;
529
530
531 rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
532 if (rv < 0)
533 return -ERESTARTSYS;
534
535 cntr = READ_ONCE(desc->length);
536 if (cntr == 0) {
537 desc->read = 0;
538retry:
539 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
540 rv = -ENODEV;
541 goto err;
542 }
543 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
544 clear_bit(WDM_OVERFLOW, addr: &desc->flags);
545 rv = -ENOBUFS;
546 goto err;
547 }
548 i++;
549 if (file->f_flags & O_NONBLOCK) {
550 if (!test_bit(WDM_READ, &desc->flags)) {
551 rv = -EAGAIN;
552 goto err;
553 }
554 rv = 0;
555 } else {
556 rv = wait_event_interruptible(desc->wait,
557 test_bit(WDM_READ, &desc->flags));
558 }
559
560 /* may have happened while we slept */
561 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
562 rv = -ENODEV;
563 goto err;
564 }
565 if (test_bit(WDM_RESETTING, &desc->flags)) {
566 rv = -EIO;
567 goto err;
568 }
569 usb_mark_last_busy(interface_to_usbdev(desc->intf));
570 if (rv < 0) {
571 rv = -ERESTARTSYS;
572 goto err;
573 }
574
575 spin_lock_irq(lock: &desc->iuspin);
576
577 if (desc->rerr) { /* read completed, error happened */
578 rv = usb_translate_errors(error_code: desc->rerr);
579 desc->rerr = 0;
580 spin_unlock_irq(lock: &desc->iuspin);
581 goto err;
582 }
583 /*
584 * recheck whether we've lost the race
585 * against the completion handler
586 */
587 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
588 spin_unlock_irq(lock: &desc->iuspin);
589 goto retry;
590 }
591
592 cntr = desc->length;
593 spin_unlock_irq(lock: &desc->iuspin);
594 }
595
596 if (cntr > count)
597 cntr = count;
598 rv = copy_to_user(to: buffer, from: desc->ubuf, n: cntr);
599 if (rv > 0) {
600 rv = -EFAULT;
601 goto err;
602 }
603
604 spin_lock_irq(lock: &desc->iuspin);
605
606 for (i = 0; i < desc->length - cntr; i++)
607 desc->ubuf[i] = desc->ubuf[i + cntr];
608
609 desc->length -= cntr;
610 /* in case we had outstanding data */
611 if (!desc->length) {
612 clear_bit(WDM_READ, addr: &desc->flags);
613 service_outstanding_interrupt(desc);
614 }
615 spin_unlock_irq(lock: &desc->iuspin);
616 rv = cntr;
617
618err:
619 mutex_unlock(lock: &desc->rlock);
620 return rv;
621}
622
623static int wdm_wait_for_response(struct file *file, long timeout)
624{
625 struct wdm_device *desc = file->private_data;
626 long rv; /* Use long here because (int) MAX_SCHEDULE_TIMEOUT < 0. */
627
628 /*
629 * Needs both flags. We cannot do with one because resetting it would
630 * cause a race with write() yet we need to signal a disconnect.
631 */
632 rv = wait_event_interruptible_timeout(desc->wait,
633 !test_bit(WDM_IN_USE, &desc->flags) ||
634 test_bit(WDM_DISCONNECTING, &desc->flags),
635 timeout);
636
637 /*
638 * To report the correct error. This is best effort.
639 * We are inevitably racing with the hardware.
640 */
641 if (test_bit(WDM_DISCONNECTING, &desc->flags))
642 return -ENODEV;
643 if (!rv)
644 return -EIO;
645 if (rv < 0)
646 return -EINTR;
647
648 spin_lock_irq(lock: &desc->iuspin);
649 rv = desc->werr;
650 desc->werr = 0;
651 spin_unlock_irq(lock: &desc->iuspin);
652
653 return usb_translate_errors(error_code: rv);
654
655}
656
657/*
658 * You need to send a signal when you react to malicious or defective hardware.
659 * Also, don't abort when fsync() returned -EINVAL, for older kernels which do
660 * not implement wdm_flush() will return -EINVAL.
661 */
662static int wdm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
663{
664 return wdm_wait_for_response(file, MAX_SCHEDULE_TIMEOUT);
665}
666
667/*
668 * Same with wdm_fsync(), except it uses finite timeout in order to react to
669 * malicious or defective hardware which ceased communication after close() was
670 * implicitly called due to process termination.
671 */
672static int wdm_flush(struct file *file, fl_owner_t id)
673{
674 return wdm_wait_for_response(file, WDM_FLUSH_TIMEOUT);
675}
676
677static __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait)
678{
679 struct wdm_device *desc = file->private_data;
680 unsigned long flags;
681 __poll_t mask = 0;
682
683 spin_lock_irqsave(&desc->iuspin, flags);
684 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
685 mask = EPOLLHUP | EPOLLERR;
686 spin_unlock_irqrestore(lock: &desc->iuspin, flags);
687 goto desc_out;
688 }
689 if (test_bit(WDM_READ, &desc->flags))
690 mask = EPOLLIN | EPOLLRDNORM;
691 if (desc->rerr || desc->werr)
692 mask |= EPOLLERR;
693 if (!test_bit(WDM_IN_USE, &desc->flags))
694 mask |= EPOLLOUT | EPOLLWRNORM;
695 spin_unlock_irqrestore(lock: &desc->iuspin, flags);
696
697 poll_wait(filp: file, wait_address: &desc->wait, p: wait);
698
699desc_out:
700 return mask;
701}
702
703static int wdm_open(struct inode *inode, struct file *file)
704{
705 int minor = iminor(inode);
706 int rv = -ENODEV;
707 struct usb_interface *intf;
708 struct wdm_device *desc;
709
710 mutex_lock(&wdm_mutex);
711 desc = wdm_find_device_by_minor(minor);
712 if (!desc)
713 goto out;
714
715 intf = desc->intf;
716 if (test_bit(WDM_DISCONNECTING, &desc->flags))
717 goto out;
718 file->private_data = desc;
719
720 if (test_bit(WDM_WWAN_IN_USE, &desc->flags)) {
721 rv = -EBUSY;
722 goto out;
723 }
724 smp_rmb(); /* ordered against wdm_wwan_port_stop() */
725 rv = usb_autopm_get_interface(intf: desc->intf);
726 if (rv < 0) {
727 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
728 goto out;
729 }
730
731 /* using write lock to protect desc->count */
732 mutex_lock(&desc->wlock);
733 if (!desc->count++) {
734 desc->werr = 0;
735 desc->rerr = 0;
736 rv = usb_submit_urb(urb: desc->validity, GFP_KERNEL);
737 if (rv < 0) {
738 desc->count--;
739 dev_err(&desc->intf->dev,
740 "Error submitting int urb - %d\n", rv);
741 rv = usb_translate_errors(error_code: rv);
742 }
743 } else {
744 rv = 0;
745 }
746 mutex_unlock(lock: &desc->wlock);
747 if (desc->count == 1)
748 desc->manage_power(intf, 1);
749 usb_autopm_put_interface(intf: desc->intf);
750out:
751 mutex_unlock(lock: &wdm_mutex);
752 return rv;
753}
754
755static int wdm_release(struct inode *inode, struct file *file)
756{
757 struct wdm_device *desc = file->private_data;
758
759 mutex_lock(&wdm_mutex);
760
761 /* using write lock to protect desc->count */
762 mutex_lock(&desc->wlock);
763 desc->count--;
764 mutex_unlock(lock: &desc->wlock);
765
766 if (!desc->count) {
767 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
768 dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n");
769 poison_urbs(desc);
770 spin_lock_irq(lock: &desc->iuspin);
771 desc->resp_count = 0;
772 clear_bit(WDM_RESPONDING, addr: &desc->flags);
773 spin_unlock_irq(lock: &desc->iuspin);
774 desc->manage_power(desc->intf, 0);
775 unpoison_urbs(desc);
776 } else {
777 /* must avoid dev_printk here as desc->intf is invalid */
778 pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
779 cleanup(desc);
780 }
781 }
782 mutex_unlock(lock: &wdm_mutex);
783 return 0;
784}
785
786static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
787{
788 struct wdm_device *desc = file->private_data;
789 int rv = 0;
790
791 switch (cmd) {
792 case IOCTL_WDM_MAX_COMMAND:
793 if (copy_to_user(to: (void __user *)arg, from: &desc->wMaxCommand, n: sizeof(desc->wMaxCommand)))
794 rv = -EFAULT;
795 break;
796 default:
797 rv = -ENOTTY;
798 }
799 return rv;
800}
801
802static const struct file_operations wdm_fops = {
803 .owner = THIS_MODULE,
804 .read = wdm_read,
805 .write = wdm_write,
806 .fsync = wdm_fsync,
807 .open = wdm_open,
808 .flush = wdm_flush,
809 .release = wdm_release,
810 .poll = wdm_poll,
811 .unlocked_ioctl = wdm_ioctl,
812 .compat_ioctl = compat_ptr_ioctl,
813 .llseek = noop_llseek,
814};
815
816static struct usb_class_driver wdm_class = {
817 .name = "cdc-wdm%d",
818 .fops = &wdm_fops,
819 .minor_base = WDM_MINOR_BASE,
820};
821
822/* --- WWAN framework integration --- */
823#ifdef CONFIG_WWAN
824static int wdm_wwan_port_start(struct wwan_port *port)
825{
826 struct wdm_device *desc = wwan_port_get_drvdata(port);
827 int rv;
828
829 /* The interface is both exposed via the WWAN framework and as a
830 * legacy usbmisc chardev. If chardev is already open, just fail
831 * to prevent concurrent usage. Otherwise, switch to WWAN mode.
832 */
833 mutex_lock(&wdm_mutex);
834 if (desc->count) {
835 mutex_unlock(lock: &wdm_mutex);
836 return -EBUSY;
837 }
838 set_bit(WDM_WWAN_IN_USE, addr: &desc->flags);
839 mutex_unlock(lock: &wdm_mutex);
840
841 desc->manage_power(desc->intf, 1);
842
843 /* tx is allowed */
844 wwan_port_txon(port);
845
846 /* Start getting events */
847 rv = usb_submit_urb(urb: desc->validity, GFP_KERNEL);
848 if (rv < 0) {
849 wwan_port_txoff(port);
850 desc->manage_power(desc->intf, 0);
851 /* this must be last lest we race with chardev open */
852 clear_bit(WDM_WWAN_IN_USE, addr: &desc->flags);
853 }
854
855 return rv;
856}
857
858static void wdm_wwan_port_stop(struct wwan_port *port)
859{
860 struct wdm_device *desc = wwan_port_get_drvdata(port);
861
862 /* Stop all transfers and disable WWAN mode */
863 poison_urbs(desc);
864 desc->manage_power(desc->intf, 0);
865 clear_bit(WDM_READ, addr: &desc->flags);
866 unpoison_urbs(desc);
867 smp_wmb(); /* ordered against wdm_open() */
868 /* this must be last lest we open a poisoned device */
869 clear_bit(WDM_WWAN_IN_USE, addr: &desc->flags);
870}
871
872static void wdm_wwan_port_tx_complete(struct urb *urb)
873{
874 struct sk_buff *skb = urb->context;
875 struct wdm_device *desc = skb_shinfo(skb)->destructor_arg;
876
877 usb_autopm_put_interface_async(intf: desc->intf);
878 wwan_port_txon(port: desc->wwanp);
879 kfree_skb(skb);
880}
881
882static int wdm_wwan_port_tx(struct wwan_port *port, struct sk_buff *skb)
883{
884 struct wdm_device *desc = wwan_port_get_drvdata(port);
885 struct usb_interface *intf = desc->intf;
886 struct usb_ctrlrequest *req = desc->orq;
887 int rv;
888
889 rv = usb_autopm_get_interface(intf);
890 if (rv)
891 return rv;
892
893 usb_fill_control_urb(
894 urb: desc->command,
895 interface_to_usbdev(intf),
896 usb_sndctrlpipe(interface_to_usbdev(intf), 0),
897 setup_packet: (unsigned char *)req,
898 transfer_buffer: skb->data,
899 buffer_length: skb->len,
900 complete_fn: wdm_wwan_port_tx_complete,
901 context: skb
902 );
903
904 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
905 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
906 req->wValue = 0;
907 req->wIndex = desc->inum; /* already converted */
908 req->wLength = cpu_to_le16(skb->len);
909
910 skb_shinfo(skb)->destructor_arg = desc;
911
912 rv = usb_submit_urb(urb: desc->command, GFP_KERNEL);
913 if (rv)
914 usb_autopm_put_interface(intf);
915 else /* One transfer at a time, stop TX until URB completion */
916 wwan_port_txoff(port);
917
918 return rv;
919}
920
921static const struct wwan_port_ops wdm_wwan_port_ops = {
922 .start = wdm_wwan_port_start,
923 .stop = wdm_wwan_port_stop,
924 .tx = wdm_wwan_port_tx,
925};
926
927static void wdm_wwan_init(struct wdm_device *desc)
928{
929 struct usb_interface *intf = desc->intf;
930 struct wwan_port *port;
931
932 /* Only register to WWAN core if protocol/type is known */
933 if (desc->wwanp_type == WWAN_PORT_UNKNOWN) {
934 dev_info(&intf->dev, "Unknown control protocol\n");
935 return;
936 }
937
938 port = wwan_create_port(parent: &intf->dev, type: desc->wwanp_type, ops: &wdm_wwan_port_ops,
939 NULL, drvdata: desc);
940 if (IS_ERR(ptr: port)) {
941 dev_err(&intf->dev, "%s: Unable to create WWAN port\n",
942 dev_name(intf->usb_dev));
943 return;
944 }
945
946 desc->wwanp = port;
947}
948
949static void wdm_wwan_deinit(struct wdm_device *desc)
950{
951 if (!desc->wwanp)
952 return;
953
954 wwan_remove_port(port: desc->wwanp);
955 desc->wwanp = NULL;
956}
957
958static void wdm_wwan_rx(struct wdm_device *desc, int length)
959{
960 struct wwan_port *port = desc->wwanp;
961 struct sk_buff *skb;
962
963 /* Forward data to WWAN port */
964 skb = alloc_skb(size: length, GFP_ATOMIC);
965 if (!skb)
966 return;
967
968 skb_put_data(skb, data: desc->inbuf, len: length);
969 wwan_port_rx(port, skb);
970
971 /* inbuf has been copied, it is safe to check for outstanding data */
972 schedule_work(work: &desc->service_outs_intr);
973}
974#else /* CONFIG_WWAN */
975static void wdm_wwan_init(struct wdm_device *desc) {}
976static void wdm_wwan_deinit(struct wdm_device *desc) {}
977static void wdm_wwan_rx(struct wdm_device *desc, int length) {}
978#endif /* CONFIG_WWAN */
979
980/* --- error handling --- */
981static void wdm_rxwork(struct work_struct *work)
982{
983 struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
984 unsigned long flags;
985 int rv = 0;
986 int responding;
987
988 spin_lock_irqsave(&desc->iuspin, flags);
989 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
990 spin_unlock_irqrestore(lock: &desc->iuspin, flags);
991 } else {
992 responding = test_and_set_bit(WDM_RESPONDING, addr: &desc->flags);
993 spin_unlock_irqrestore(lock: &desc->iuspin, flags);
994 if (!responding)
995 rv = usb_submit_urb(urb: desc->response, GFP_KERNEL);
996 if (rv < 0 && rv != -EPERM) {
997 spin_lock_irqsave(&desc->iuspin, flags);
998 clear_bit(WDM_RESPONDING, addr: &desc->flags);
999 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
1000 schedule_work(work: &desc->rxwork);
1001 spin_unlock_irqrestore(lock: &desc->iuspin, flags);
1002 }
1003 }
1004}
1005
1006static void service_interrupt_work(struct work_struct *work)
1007{
1008 struct wdm_device *desc;
1009
1010 desc = container_of(work, struct wdm_device, service_outs_intr);
1011
1012 spin_lock_irq(lock: &desc->iuspin);
1013 service_outstanding_interrupt(desc);
1014 if (!desc->resp_count && (desc->length || desc->rerr)) {
1015 set_bit(WDM_READ, addr: &desc->flags);
1016 wake_up(&desc->wait);
1017 }
1018 spin_unlock_irq(lock: &desc->iuspin);
1019}
1020
1021/* --- hotplug --- */
1022
1023static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
1024 u16 bufsize, enum wwan_port_type type,
1025 int (*manage_power)(struct usb_interface *, int))
1026{
1027 int rv = -ENOMEM;
1028 struct wdm_device *desc;
1029
1030 desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
1031 if (!desc)
1032 goto out;
1033 INIT_LIST_HEAD(list: &desc->device_list);
1034 mutex_init(&desc->rlock);
1035 mutex_init(&desc->wlock);
1036 spin_lock_init(&desc->iuspin);
1037 init_waitqueue_head(&desc->wait);
1038 desc->wMaxCommand = bufsize;
1039 /* this will be expanded and needed in hardware endianness */
1040 desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
1041 desc->intf = intf;
1042 desc->wwanp_type = type;
1043 INIT_WORK(&desc->rxwork, wdm_rxwork);
1044 INIT_WORK(&desc->service_outs_intr, service_interrupt_work);
1045
1046 if (!usb_endpoint_is_int_in(epd: ep)) {
1047 rv = -EINVAL;
1048 goto err;
1049 }
1050
1051 desc->wMaxPacketSize = usb_endpoint_maxp(epd: ep);
1052
1053 desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
1054 if (!desc->orq)
1055 goto err;
1056 desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
1057 if (!desc->irq)
1058 goto err;
1059
1060 desc->validity = usb_alloc_urb(iso_packets: 0, GFP_KERNEL);
1061 if (!desc->validity)
1062 goto err;
1063
1064 desc->response = usb_alloc_urb(iso_packets: 0, GFP_KERNEL);
1065 if (!desc->response)
1066 goto err;
1067
1068 desc->command = usb_alloc_urb(iso_packets: 0, GFP_KERNEL);
1069 if (!desc->command)
1070 goto err;
1071
1072 desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
1073 if (!desc->ubuf)
1074 goto err;
1075
1076 desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
1077 if (!desc->sbuf)
1078 goto err;
1079
1080 desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
1081 if (!desc->inbuf)
1082 goto err;
1083
1084 usb_fill_int_urb(
1085 urb: desc->validity,
1086 interface_to_usbdev(intf),
1087 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
1088 transfer_buffer: desc->sbuf,
1089 buffer_length: desc->wMaxPacketSize,
1090 complete_fn: wdm_int_callback,
1091 context: desc,
1092 interval: ep->bInterval
1093 );
1094
1095 desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
1096 desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
1097 desc->irq->wValue = 0;
1098 desc->irq->wIndex = desc->inum; /* already converted */
1099 desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
1100
1101 usb_fill_control_urb(
1102 urb: desc->response,
1103 interface_to_usbdev(intf),
1104 /* using common endpoint 0 */
1105 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
1106 setup_packet: (unsigned char *)desc->irq,
1107 transfer_buffer: desc->inbuf,
1108 buffer_length: desc->wMaxCommand,
1109 complete_fn: wdm_in_callback,
1110 context: desc
1111 );
1112
1113 desc->manage_power = manage_power;
1114
1115 spin_lock(lock: &wdm_device_list_lock);
1116 list_add(new: &desc->device_list, head: &wdm_device_list);
1117 spin_unlock(lock: &wdm_device_list_lock);
1118
1119 rv = usb_register_dev(intf, class_driver: &wdm_class);
1120 if (rv < 0)
1121 goto err;
1122 else
1123 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
1124
1125 wdm_wwan_init(desc);
1126
1127out:
1128 return rv;
1129err:
1130 spin_lock(lock: &wdm_device_list_lock);
1131 list_del(entry: &desc->device_list);
1132 spin_unlock(lock: &wdm_device_list_lock);
1133 cleanup(desc);
1134 return rv;
1135}
1136
1137static int wdm_manage_power(struct usb_interface *intf, int on)
1138{
1139 /* need autopm_get/put here to ensure the usbcore sees the new value */
1140 int rv = usb_autopm_get_interface(intf);
1141
1142 intf->needs_remote_wakeup = on;
1143 if (!rv)
1144 usb_autopm_put_interface(intf);
1145 return 0;
1146}
1147
1148static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
1149{
1150 int rv = -EINVAL;
1151 struct usb_host_interface *iface;
1152 struct usb_endpoint_descriptor *ep;
1153 struct usb_cdc_parsed_header hdr;
1154 u8 *buffer = intf->altsetting->extra;
1155 int buflen = intf->altsetting->extralen;
1156 u16 maxcom = WDM_DEFAULT_BUFSIZE;
1157
1158 if (!buffer)
1159 goto err;
1160
1161 cdc_parse_cdc_header(hdr: &hdr, intf, buffer, buflen);
1162
1163 if (hdr.usb_cdc_dmm_desc)
1164 maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand);
1165
1166 iface = intf->cur_altsetting;
1167 if (iface->desc.bNumEndpoints != 1)
1168 goto err;
1169 ep = &iface->endpoint[0].desc;
1170
1171 rv = wdm_create(intf, ep, bufsize: maxcom, type: WWAN_PORT_UNKNOWN, manage_power: &wdm_manage_power);
1172
1173err:
1174 return rv;
1175}
1176
1177/**
1178 * usb_cdc_wdm_register - register a WDM subdriver
1179 * @intf: usb interface the subdriver will associate with
1180 * @ep: interrupt endpoint to monitor for notifications
1181 * @bufsize: maximum message size to support for read/write
1182 * @type: Type/protocol of the transported data (MBIM, QMI...)
1183 * @manage_power: call-back invoked during open and release to
1184 * manage the device's power
1185 * Create WDM usb class character device and associate it with intf
1186 * without binding, allowing another driver to manage the interface.
1187 *
1188 * The subdriver will manage the given interrupt endpoint exclusively
1189 * and will issue control requests referring to the given intf. It
1190 * will otherwise avoid interferring, and in particular not do
1191 * usb_set_intfdata/usb_get_intfdata on intf.
1192 *
1193 * The return value is a pointer to the subdriver's struct usb_driver.
1194 * The registering driver is responsible for calling this subdriver's
1195 * disconnect, suspend, resume, pre_reset and post_reset methods from
1196 * its own.
1197 */
1198struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
1199 struct usb_endpoint_descriptor *ep,
1200 int bufsize, enum wwan_port_type type,
1201 int (*manage_power)(struct usb_interface *, int))
1202{
1203 int rv;
1204
1205 rv = wdm_create(intf, ep, bufsize, type, manage_power);
1206 if (rv < 0)
1207 goto err;
1208
1209 return &wdm_driver;
1210err:
1211 return ERR_PTR(error: rv);
1212}
1213EXPORT_SYMBOL(usb_cdc_wdm_register);
1214
1215static void wdm_disconnect(struct usb_interface *intf)
1216{
1217 struct wdm_device *desc;
1218 unsigned long flags;
1219
1220 usb_deregister_dev(intf, class_driver: &wdm_class);
1221 desc = wdm_find_device(intf);
1222 mutex_lock(&wdm_mutex);
1223
1224 wdm_wwan_deinit(desc);
1225
1226 /* the spinlock makes sure no new urbs are generated in the callbacks */
1227 spin_lock_irqsave(&desc->iuspin, flags);
1228 set_bit(WDM_DISCONNECTING, addr: &desc->flags);
1229 set_bit(WDM_READ, addr: &desc->flags);
1230 spin_unlock_irqrestore(lock: &desc->iuspin, flags);
1231 wake_up_all(&desc->wait);
1232 mutex_lock(&desc->rlock);
1233 mutex_lock(&desc->wlock);
1234 poison_urbs(desc);
1235 cancel_work_sync(work: &desc->rxwork);
1236 cancel_work_sync(work: &desc->service_outs_intr);
1237 mutex_unlock(lock: &desc->wlock);
1238 mutex_unlock(lock: &desc->rlock);
1239
1240 /* the desc->intf pointer used as list key is now invalid */
1241 spin_lock(lock: &wdm_device_list_lock);
1242 list_del(entry: &desc->device_list);
1243 spin_unlock(lock: &wdm_device_list_lock);
1244
1245 if (!desc->count)
1246 cleanup(desc);
1247 else
1248 dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count);
1249 mutex_unlock(lock: &wdm_mutex);
1250}
1251
1252#ifdef CONFIG_PM
1253static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
1254{
1255 struct wdm_device *desc = wdm_find_device(intf);
1256 int rv = 0;
1257
1258 dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
1259
1260 /* if this is an autosuspend the caller does the locking */
1261 if (!PMSG_IS_AUTO(message)) {
1262 mutex_lock(&desc->rlock);
1263 mutex_lock(&desc->wlock);
1264 }
1265 spin_lock_irq(lock: &desc->iuspin);
1266
1267 if (PMSG_IS_AUTO(message) &&
1268 (test_bit(WDM_IN_USE, &desc->flags)
1269 || test_bit(WDM_RESPONDING, &desc->flags))) {
1270 spin_unlock_irq(lock: &desc->iuspin);
1271 rv = -EBUSY;
1272 } else {
1273
1274 set_bit(WDM_SUSPENDING, addr: &desc->flags);
1275 spin_unlock_irq(lock: &desc->iuspin);
1276 /* callback submits work - order is essential */
1277 poison_urbs(desc);
1278 cancel_work_sync(work: &desc->rxwork);
1279 cancel_work_sync(work: &desc->service_outs_intr);
1280 unpoison_urbs(desc);
1281 }
1282 if (!PMSG_IS_AUTO(message)) {
1283 mutex_unlock(lock: &desc->wlock);
1284 mutex_unlock(lock: &desc->rlock);
1285 }
1286
1287 return rv;
1288}
1289#endif
1290
1291static int recover_from_urb_loss(struct wdm_device *desc)
1292{
1293 int rv = 0;
1294
1295 if (desc->count) {
1296 rv = usb_submit_urb(urb: desc->validity, GFP_NOIO);
1297 if (rv < 0)
1298 dev_err(&desc->intf->dev,
1299 "Error resume submitting int urb - %d\n", rv);
1300 }
1301 return rv;
1302}
1303
1304#ifdef CONFIG_PM
1305static int wdm_resume(struct usb_interface *intf)
1306{
1307 struct wdm_device *desc = wdm_find_device(intf);
1308 int rv;
1309
1310 dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1311
1312 clear_bit(WDM_SUSPENDING, addr: &desc->flags);
1313 rv = recover_from_urb_loss(desc);
1314
1315 return rv;
1316}
1317#endif
1318
1319static int wdm_pre_reset(struct usb_interface *intf)
1320{
1321 struct wdm_device *desc = wdm_find_device(intf);
1322
1323 /*
1324 * we notify everybody using poll of
1325 * an exceptional situation
1326 * must be done before recovery lest a spontaneous
1327 * message from the device is lost
1328 */
1329 spin_lock_irq(lock: &desc->iuspin);
1330 set_bit(WDM_RESETTING, addr: &desc->flags); /* inform read/write */
1331 set_bit(WDM_READ, addr: &desc->flags); /* unblock read */
1332 clear_bit(WDM_IN_USE, addr: &desc->flags); /* unblock write */
1333 desc->rerr = -EINTR;
1334 spin_unlock_irq(lock: &desc->iuspin);
1335 wake_up_all(&desc->wait);
1336 mutex_lock(&desc->rlock);
1337 mutex_lock(&desc->wlock);
1338 poison_urbs(desc);
1339 cancel_work_sync(work: &desc->rxwork);
1340 cancel_work_sync(work: &desc->service_outs_intr);
1341 return 0;
1342}
1343
1344static int wdm_post_reset(struct usb_interface *intf)
1345{
1346 struct wdm_device *desc = wdm_find_device(intf);
1347 int rv;
1348
1349 unpoison_urbs(desc);
1350 clear_bit(WDM_OVERFLOW, addr: &desc->flags);
1351 clear_bit(WDM_RESETTING, addr: &desc->flags);
1352 rv = recover_from_urb_loss(desc);
1353 mutex_unlock(lock: &desc->wlock);
1354 mutex_unlock(lock: &desc->rlock);
1355 return rv;
1356}
1357
1358static struct usb_driver wdm_driver = {
1359 .name = "cdc_wdm",
1360 .probe = wdm_probe,
1361 .disconnect = wdm_disconnect,
1362#ifdef CONFIG_PM
1363 .suspend = wdm_suspend,
1364 .resume = wdm_resume,
1365 .reset_resume = wdm_resume,
1366#endif
1367 .pre_reset = wdm_pre_reset,
1368 .post_reset = wdm_post_reset,
1369 .id_table = wdm_ids,
1370 .supports_autosuspend = 1,
1371 .disable_hub_initiated_lpm = 1,
1372};
1373
1374module_usb_driver(wdm_driver);
1375
1376MODULE_AUTHOR(DRIVER_AUTHOR);
1377MODULE_DESCRIPTION(DRIVER_DESC);
1378MODULE_LICENSE("GPL");
1379

source code of linux/drivers/usb/class/cdc-wdm.c