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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/usb.h>
25#include <linux/usb/cdc.h>
26#include <asm/byteorder.h>
27#include <asm/unaligned.h>
28#include <linux/usb/cdc-wdm.h>
29
30#define DRIVER_AUTHOR "Oliver Neukum"
31#define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
32
33static const struct usb_device_id wdm_ids[] = {
34 {
35 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
36 USB_DEVICE_ID_MATCH_INT_SUBCLASS,
37 .bInterfaceClass = USB_CLASS_COMM,
38 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
39 },
40 { }
41};
42
43MODULE_DEVICE_TABLE (usb, wdm_ids);
44
45#define WDM_MINOR_BASE 176
46
47
48#define WDM_IN_USE 1
49#define WDM_DISCONNECTING 2
50#define WDM_RESULT 3
51#define WDM_READ 4
52#define WDM_INT_STALL 5
53#define WDM_POLL_RUNNING 6
54#define WDM_RESPONDING 7
55#define WDM_SUSPENDING 8
56#define WDM_RESETTING 9
57#define WDM_OVERFLOW 10
58
59#define WDM_MAX 16
60
61/* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
62#define WDM_DEFAULT_BUFSIZE 256
63
64static DEFINE_MUTEX(wdm_mutex);
65static DEFINE_SPINLOCK(wdm_device_list_lock);
66static LIST_HEAD(wdm_device_list);
67
68/* --- method tables --- */
69
70struct wdm_device {
71 u8 *inbuf; /* buffer for response */
72 u8 *outbuf; /* buffer for command */
73 u8 *sbuf; /* buffer for status */
74 u8 *ubuf; /* buffer for copy to user space */
75
76 struct urb *command;
77 struct urb *response;
78 struct urb *validity;
79 struct usb_interface *intf;
80 struct usb_ctrlrequest *orq;
81 struct usb_ctrlrequest *irq;
82 spinlock_t iuspin;
83
84 unsigned long flags;
85 u16 bufsize;
86 u16 wMaxCommand;
87 u16 wMaxPacketSize;
88 __le16 inum;
89 int reslength;
90 int length;
91 int read;
92 int count;
93 dma_addr_t shandle;
94 dma_addr_t ihandle;
95 struct mutex wlock;
96 struct mutex rlock;
97 wait_queue_head_t wait;
98 struct work_struct rxwork;
99 struct work_struct service_outs_intr;
100 int werr;
101 int rerr;
102 int resp_count;
103
104 struct list_head device_list;
105 int (*manage_power)(struct usb_interface *, int);
106};
107
108static struct usb_driver wdm_driver;
109
110/* return intfdata if we own the interface, else look up intf in the list */
111static 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;
120found:
121 spin_unlock(&wdm_device_list_lock);
122
123 return desc;
124}
125
126static 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;
135found:
136 spin_unlock(&wdm_device_list_lock);
137
138 return desc;
139}
140
141/* --- callbacks --- */
142static void wdm_out_callback(struct urb *urb)
143{
144 struct wdm_device *desc;
145 unsigned long flags;
146
147 desc = urb->context;
148 spin_lock_irqsave(&desc->iuspin, flags);
149 desc->werr = urb->status;
150 spin_unlock_irqrestore(&desc->iuspin, flags);
151 kfree(desc->outbuf);
152 desc->outbuf = NULL;
153 clear_bit(WDM_IN_USE, &desc->flags);
154 wake_up(&desc->wait);
155}
156
157static void wdm_in_callback(struct urb *urb)
158{
159 unsigned long flags;
160 struct wdm_device *desc = urb->context;
161 int status = urb->status;
162 int length = urb->actual_length;
163
164 spin_lock_irqsave(&desc->iuspin, flags);
165 clear_bit(WDM_RESPONDING, &desc->flags);
166
167 if (status) {
168 switch (status) {
169 case -ENOENT:
170 dev_dbg(&desc->intf->dev,
171 "nonzero urb status received: -ENOENT\n");
172 goto skip_error;
173 case -ECONNRESET:
174 dev_dbg(&desc->intf->dev,
175 "nonzero urb status received: -ECONNRESET\n");
176 goto skip_error;
177 case -ESHUTDOWN:
178 dev_dbg(&desc->intf->dev,
179 "nonzero urb status received: -ESHUTDOWN\n");
180 goto skip_error;
181 case -EPIPE:
182 dev_err(&desc->intf->dev,
183 "nonzero urb status received: -EPIPE\n");
184 break;
185 default:
186 dev_err(&desc->intf->dev,
187 "Unexpected error %d\n", status);
188 break;
189 }
190 }
191
192 /*
193 * only set a new error if there is no previous error.
194 * Errors are only cleared during read/open
195 * Avoid propagating -EPIPE (stall) to userspace since it is
196 * better handled as an empty read
197 */
198 if (desc->rerr == 0 && status != -EPIPE)
199 desc->rerr = status;
200
201 if (length + desc->length > desc->wMaxCommand) {
202 /* The buffer would overflow */
203 set_bit(WDM_OVERFLOW, &desc->flags);
204 } else {
205 /* we may already be in overflow */
206 if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
207 memmove(desc->ubuf + desc->length, desc->inbuf, length);
208 desc->length += length;
209 desc->reslength = length;
210 }
211 }
212skip_error:
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 schedule_work(&desc->service_outs_intr);
222 } else {
223 set_bit(WDM_READ, &desc->flags);
224 wake_up(&desc->wait);
225 }
226 spin_unlock_irqrestore(&desc->iuspin, flags);
227}
228
229static void wdm_int_callback(struct urb *urb)
230{
231 unsigned long flags;
232 int rv = 0;
233 int responding;
234 int status = urb->status;
235 struct wdm_device *desc;
236 struct usb_cdc_notification *dr;
237
238 desc = urb->context;
239 dr = (struct usb_cdc_notification *)desc->sbuf;
240
241 if (status) {
242 switch (status) {
243 case -ESHUTDOWN:
244 case -ENOENT:
245 case -ECONNRESET:
246 return; /* unplug */
247 case -EPIPE:
248 set_bit(WDM_INT_STALL, &desc->flags);
249 dev_err(&desc->intf->dev, "Stall on int endpoint\n");
250 goto sw; /* halt is cleared in work */
251 default:
252 dev_err(&desc->intf->dev,
253 "nonzero urb status received: %d\n", status);
254 break;
255 }
256 }
257
258 if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
259 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
260 urb->actual_length);
261 goto exit;
262 }
263
264 switch (dr->bNotificationType) {
265 case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
266 dev_dbg(&desc->intf->dev,
267 "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d\n",
268 le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength));
269 break;
270
271 case USB_CDC_NOTIFY_NETWORK_CONNECTION:
272
273 dev_dbg(&desc->intf->dev,
274 "NOTIFY_NETWORK_CONNECTION %s network\n",
275 dr->wValue ? "connected to" : "disconnected from");
276 goto exit;
277 case USB_CDC_NOTIFY_SPEED_CHANGE:
278 dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)\n",
279 urb->actual_length);
280 goto exit;
281 default:
282 clear_bit(WDM_POLL_RUNNING, &desc->flags);
283 dev_err(&desc->intf->dev,
284 "unknown notification %d received: index %d len %d\n",
285 dr->bNotificationType,
286 le16_to_cpu(dr->wIndex),
287 le16_to_cpu(dr->wLength));
288 goto exit;
289 }
290
291 spin_lock_irqsave(&desc->iuspin, flags);
292 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
293 if (!desc->resp_count++ && !responding
294 && !test_bit(WDM_DISCONNECTING, &desc->flags)
295 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
296 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
297 dev_dbg(&desc->intf->dev, "submit response URB %d\n", rv);
298 }
299 spin_unlock_irqrestore(&desc->iuspin, flags);
300 if (rv < 0) {
301 clear_bit(WDM_RESPONDING, &desc->flags);
302 if (rv == -EPERM)
303 return;
304 if (rv == -ENOMEM) {
305sw:
306 rv = schedule_work(&desc->rxwork);
307 if (rv)
308 dev_err(&desc->intf->dev,
309 "Cannot schedule work\n");
310 }
311 }
312exit:
313 rv = usb_submit_urb(urb, GFP_ATOMIC);
314 if (rv)
315 dev_err(&desc->intf->dev,
316 "%s - usb_submit_urb failed with result %d\n",
317 __func__, rv);
318
319}
320
321static void kill_urbs(struct wdm_device *desc)
322{
323 /* the order here is essential */
324 usb_kill_urb(desc->command);
325 usb_kill_urb(desc->validity);
326 usb_kill_urb(desc->response);
327}
328
329static void free_urbs(struct wdm_device *desc)
330{
331 usb_free_urb(desc->validity);
332 usb_free_urb(desc->response);
333 usb_free_urb(desc->command);
334}
335
336static void cleanup(struct wdm_device *desc)
337{
338 kfree(desc->sbuf);
339 kfree(desc->inbuf);
340 kfree(desc->orq);
341 kfree(desc->irq);
342 kfree(desc->ubuf);
343 free_urbs(desc);
344 kfree(desc);
345}
346
347static ssize_t wdm_write
348(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
349{
350 u8 *buf;
351 int rv = -EMSGSIZE, r, we;
352 struct wdm_device *desc = file->private_data;
353 struct usb_ctrlrequest *req;
354
355 if (count > desc->wMaxCommand)
356 count = desc->wMaxCommand;
357
358 spin_lock_irq(&desc->iuspin);
359 we = desc->werr;
360 desc->werr = 0;
361 spin_unlock_irq(&desc->iuspin);
362 if (we < 0)
363 return usb_translate_errors(we);
364
365 buf = memdup_user(buffer, count);
366 if (IS_ERR(buf))
367 return PTR_ERR(buf);
368
369 /* concurrent writes and disconnect */
370 r = mutex_lock_interruptible(&desc->wlock);
371 rv = -ERESTARTSYS;
372 if (r)
373 goto out_free_mem;
374
375 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
376 rv = -ENODEV;
377 goto out_free_mem_lock;
378 }
379
380 r = usb_autopm_get_interface(desc->intf);
381 if (r < 0) {
382 rv = usb_translate_errors(r);
383 goto out_free_mem_lock;
384 }
385
386 if (!(file->f_flags & O_NONBLOCK))
387 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
388 &desc->flags));
389 else
390 if (test_bit(WDM_IN_USE, &desc->flags))
391 r = -EAGAIN;
392
393 if (test_bit(WDM_RESETTING, &desc->flags))
394 r = -EIO;
395
396 if (r < 0) {
397 rv = r;
398 goto out_free_mem_pm;
399 }
400
401 req = desc->orq;
402 usb_fill_control_urb(
403 desc->command,
404 interface_to_usbdev(desc->intf),
405 /* using common endpoint 0 */
406 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
407 (unsigned char *)req,
408 buf,
409 count,
410 wdm_out_callback,
411 desc
412 );
413
414 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
415 USB_RECIP_INTERFACE);
416 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
417 req->wValue = 0;
418 req->wIndex = desc->inum; /* already converted */
419 req->wLength = cpu_to_le16(count);
420 set_bit(WDM_IN_USE, &desc->flags);
421 desc->outbuf = buf;
422
423 rv = usb_submit_urb(desc->command, GFP_KERNEL);
424 if (rv < 0) {
425 desc->outbuf = NULL;
426 clear_bit(WDM_IN_USE, &desc->flags);
427 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
428 rv = usb_translate_errors(rv);
429 goto out_free_mem_pm;
430 } else {
431 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d\n",
432 le16_to_cpu(req->wIndex));
433 }
434
435 usb_autopm_put_interface(desc->intf);
436 mutex_unlock(&desc->wlock);
437 return count;
438
439out_free_mem_pm:
440 usb_autopm_put_interface(desc->intf);
441out_free_mem_lock:
442 mutex_unlock(&desc->wlock);
443out_free_mem:
444 kfree(buf);
445 return rv;
446}
447
448/*
449 * Submit the read urb if resp_count is non-zero.
450 *
451 * Called with desc->iuspin locked
452 */
453static int service_outstanding_interrupt(struct wdm_device *desc)
454{
455 int rv = 0;
456
457 /* submit read urb only if the device is waiting for it */
458 if (!desc->resp_count || !--desc->resp_count)
459 goto out;
460
461 set_bit(WDM_RESPONDING, &desc->flags);
462 spin_unlock_irq(&desc->iuspin);
463 rv = usb_submit_urb(desc->response, GFP_KERNEL);
464 spin_lock_irq(&desc->iuspin);
465 if (rv) {
466 dev_err(&desc->intf->dev,
467 "usb_submit_urb failed with result %d\n", rv);
468
469 /* make sure the next notification trigger a submit */
470 clear_bit(WDM_RESPONDING, &desc->flags);
471 desc->resp_count = 0;
472 }
473out:
474 return rv;
475}
476
477static ssize_t wdm_read
478(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
479{
480 int rv, cntr;
481 int i = 0;
482 struct wdm_device *desc = file->private_data;
483
484
485 rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
486 if (rv < 0)
487 return -ERESTARTSYS;
488
489 cntr = READ_ONCE(desc->length);
490 if (cntr == 0) {
491 desc->read = 0;
492retry:
493 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
494 rv = -ENODEV;
495 goto err;
496 }
497 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
498 clear_bit(WDM_OVERFLOW, &desc->flags);
499 rv = -ENOBUFS;
500 goto err;
501 }
502 i++;
503 if (file->f_flags & O_NONBLOCK) {
504 if (!test_bit(WDM_READ, &desc->flags)) {
505 rv = -EAGAIN;
506 goto err;
507 }
508 rv = 0;
509 } else {
510 rv = wait_event_interruptible(desc->wait,
511 test_bit(WDM_READ, &desc->flags));
512 }
513
514 /* may have happened while we slept */
515 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
516 rv = -ENODEV;
517 goto err;
518 }
519 if (test_bit(WDM_RESETTING, &desc->flags)) {
520 rv = -EIO;
521 goto err;
522 }
523 usb_mark_last_busy(interface_to_usbdev(desc->intf));
524 if (rv < 0) {
525 rv = -ERESTARTSYS;
526 goto err;
527 }
528
529 spin_lock_irq(&desc->iuspin);
530
531 if (desc->rerr) { /* read completed, error happened */
532 rv = usb_translate_errors(desc->rerr);
533 desc->rerr = 0;
534 spin_unlock_irq(&desc->iuspin);
535 goto err;
536 }
537 /*
538 * recheck whether we've lost the race
539 * against the completion handler
540 */
541 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
542 spin_unlock_irq(&desc->iuspin);
543 goto retry;
544 }
545
546 if (!desc->reslength) { /* zero length read */
547 dev_dbg(&desc->intf->dev, "zero length - clearing WDM_READ\n");
548 clear_bit(WDM_READ, &desc->flags);
549 rv = service_outstanding_interrupt(desc);
550 spin_unlock_irq(&desc->iuspin);
551 if (rv < 0)
552 goto err;
553 goto retry;
554 }
555 cntr = desc->length;
556 spin_unlock_irq(&desc->iuspin);
557 }
558
559 if (cntr > count)
560 cntr = count;
561 rv = copy_to_user(buffer, desc->ubuf, cntr);
562 if (rv > 0) {
563 rv = -EFAULT;
564 goto err;
565 }
566
567 spin_lock_irq(&desc->iuspin);
568
569 for (i = 0; i < desc->length - cntr; i++)
570 desc->ubuf[i] = desc->ubuf[i + cntr];
571
572 desc->length -= cntr;
573 /* in case we had outstanding data */
574 if (!desc->length) {
575 clear_bit(WDM_READ, &desc->flags);
576 service_outstanding_interrupt(desc);
577 }
578 spin_unlock_irq(&desc->iuspin);
579 rv = cntr;
580
581err:
582 mutex_unlock(&desc->rlock);
583 return rv;
584}
585
586static int wdm_flush(struct file *file, fl_owner_t id)
587{
588 struct wdm_device *desc = file->private_data;
589
590 wait_event(desc->wait,
591 /*
592 * needs both flags. We cannot do with one
593 * because resetting it would cause a race
594 * with write() yet we need to signal
595 * a disconnect
596 */
597 !test_bit(WDM_IN_USE, &desc->flags) ||
598 test_bit(WDM_DISCONNECTING, &desc->flags));
599
600 /* cannot dereference desc->intf if WDM_DISCONNECTING */
601 if (test_bit(WDM_DISCONNECTING, &desc->flags))
602 return -ENODEV;
603 if (desc->werr < 0)
604 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
605 desc->werr);
606
607 return usb_translate_errors(desc->werr);
608}
609
610static __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait)
611{
612 struct wdm_device *desc = file->private_data;
613 unsigned long flags;
614 __poll_t mask = 0;
615
616 spin_lock_irqsave(&desc->iuspin, flags);
617 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
618 mask = EPOLLHUP | EPOLLERR;
619 spin_unlock_irqrestore(&desc->iuspin, flags);
620 goto desc_out;
621 }
622 if (test_bit(WDM_READ, &desc->flags))
623 mask = EPOLLIN | EPOLLRDNORM;
624 if (desc->rerr || desc->werr)
625 mask |= EPOLLERR;
626 if (!test_bit(WDM_IN_USE, &desc->flags))
627 mask |= EPOLLOUT | EPOLLWRNORM;
628 spin_unlock_irqrestore(&desc->iuspin, flags);
629
630 poll_wait(file, &desc->wait, wait);
631
632desc_out:
633 return mask;
634}
635
636static int wdm_open(struct inode *inode, struct file *file)
637{
638 int minor = iminor(inode);
639 int rv = -ENODEV;
640 struct usb_interface *intf;
641 struct wdm_device *desc;
642
643 mutex_lock(&wdm_mutex);
644 desc = wdm_find_device_by_minor(minor);
645 if (!desc)
646 goto out;
647
648 intf = desc->intf;
649 if (test_bit(WDM_DISCONNECTING, &desc->flags))
650 goto out;
651 file->private_data = desc;
652
653 rv = usb_autopm_get_interface(desc->intf);
654 if (rv < 0) {
655 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
656 goto out;
657 }
658
659 /* using write lock to protect desc->count */
660 mutex_lock(&desc->wlock);
661 if (!desc->count++) {
662 desc->werr = 0;
663 desc->rerr = 0;
664 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
665 if (rv < 0) {
666 desc->count--;
667 dev_err(&desc->intf->dev,
668 "Error submitting int urb - %d\n", rv);
669 rv = usb_translate_errors(rv);
670 }
671 } else {
672 rv = 0;
673 }
674 mutex_unlock(&desc->wlock);
675 if (desc->count == 1)
676 desc->manage_power(intf, 1);
677 usb_autopm_put_interface(desc->intf);
678out:
679 mutex_unlock(&wdm_mutex);
680 return rv;
681}
682
683static int wdm_release(struct inode *inode, struct file *file)
684{
685 struct wdm_device *desc = file->private_data;
686
687 mutex_lock(&wdm_mutex);
688
689 /* using write lock to protect desc->count */
690 mutex_lock(&desc->wlock);
691 desc->count--;
692 mutex_unlock(&desc->wlock);
693
694 if (!desc->count) {
695 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
696 dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n");
697 kill_urbs(desc);
698 spin_lock_irq(&desc->iuspin);
699 desc->resp_count = 0;
700 spin_unlock_irq(&desc->iuspin);
701 desc->manage_power(desc->intf, 0);
702 } else {
703 /* must avoid dev_printk here as desc->intf is invalid */
704 pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
705 cleanup(desc);
706 }
707 }
708 mutex_unlock(&wdm_mutex);
709 return 0;
710}
711
712static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
713{
714 struct wdm_device *desc = file->private_data;
715 int rv = 0;
716
717 switch (cmd) {
718 case IOCTL_WDM_MAX_COMMAND:
719 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
720 rv = -EFAULT;
721 break;
722 default:
723 rv = -ENOTTY;
724 }
725 return rv;
726}
727
728static const struct file_operations wdm_fops = {
729 .owner = THIS_MODULE,
730 .read = wdm_read,
731 .write = wdm_write,
732 .open = wdm_open,
733 .flush = wdm_flush,
734 .release = wdm_release,
735 .poll = wdm_poll,
736 .unlocked_ioctl = wdm_ioctl,
737 .compat_ioctl = compat_ptr_ioctl,
738 .llseek = noop_llseek,
739};
740
741static struct usb_class_driver wdm_class = {
742 .name = "cdc-wdm%d",
743 .fops = &wdm_fops,
744 .minor_base = WDM_MINOR_BASE,
745};
746
747/* --- error handling --- */
748static void wdm_rxwork(struct work_struct *work)
749{
750 struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
751 unsigned long flags;
752 int rv = 0;
753 int responding;
754
755 spin_lock_irqsave(&desc->iuspin, flags);
756 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
757 spin_unlock_irqrestore(&desc->iuspin, flags);
758 } else {
759 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
760 spin_unlock_irqrestore(&desc->iuspin, flags);
761 if (!responding)
762 rv = usb_submit_urb(desc->response, GFP_KERNEL);
763 if (rv < 0 && rv != -EPERM) {
764 spin_lock_irqsave(&desc->iuspin, flags);
765 clear_bit(WDM_RESPONDING, &desc->flags);
766 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
767 schedule_work(&desc->rxwork);
768 spin_unlock_irqrestore(&desc->iuspin, flags);
769 }
770 }
771}
772
773static void service_interrupt_work(struct work_struct *work)
774{
775 struct wdm_device *desc;
776
777 desc = container_of(work, struct wdm_device, service_outs_intr);
778
779 spin_lock_irq(&desc->iuspin);
780 service_outstanding_interrupt(desc);
781 if (!desc->resp_count) {
782 set_bit(WDM_READ, &desc->flags);
783 wake_up(&desc->wait);
784 }
785 spin_unlock_irq(&desc->iuspin);
786}
787
788/* --- hotplug --- */
789
790static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
791 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
792{
793 int rv = -ENOMEM;
794 struct wdm_device *desc;
795
796 desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
797 if (!desc)
798 goto out;
799 INIT_LIST_HEAD(&desc->device_list);
800 mutex_init(&desc->rlock);
801 mutex_init(&desc->wlock);
802 spin_lock_init(&desc->iuspin);
803 init_waitqueue_head(&desc->wait);
804 desc->wMaxCommand = bufsize;
805 /* this will be expanded and needed in hardware endianness */
806 desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
807 desc->intf = intf;
808 INIT_WORK(&desc->rxwork, wdm_rxwork);
809 INIT_WORK(&desc->service_outs_intr, service_interrupt_work);
810
811 rv = -EINVAL;
812 if (!usb_endpoint_is_int_in(ep))
813 goto err;
814
815 desc->wMaxPacketSize = usb_endpoint_maxp(ep);
816
817 desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
818 if (!desc->orq)
819 goto err;
820 desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
821 if (!desc->irq)
822 goto err;
823
824 desc->validity = usb_alloc_urb(0, GFP_KERNEL);
825 if (!desc->validity)
826 goto err;
827
828 desc->response = usb_alloc_urb(0, GFP_KERNEL);
829 if (!desc->response)
830 goto err;
831
832 desc->command = usb_alloc_urb(0, GFP_KERNEL);
833 if (!desc->command)
834 goto err;
835
836 desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
837 if (!desc->ubuf)
838 goto err;
839
840 desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
841 if (!desc->sbuf)
842 goto err;
843
844 desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
845 if (!desc->inbuf)
846 goto err;
847
848 usb_fill_int_urb(
849 desc->validity,
850 interface_to_usbdev(intf),
851 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
852 desc->sbuf,
853 desc->wMaxPacketSize,
854 wdm_int_callback,
855 desc,
856 ep->bInterval
857 );
858
859 desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
860 desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
861 desc->irq->wValue = 0;
862 desc->irq->wIndex = desc->inum; /* already converted */
863 desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
864
865 usb_fill_control_urb(
866 desc->response,
867 interface_to_usbdev(intf),
868 /* using common endpoint 0 */
869 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
870 (unsigned char *)desc->irq,
871 desc->inbuf,
872 desc->wMaxCommand,
873 wdm_in_callback,
874 desc
875 );
876
877 desc->manage_power = manage_power;
878
879 spin_lock(&wdm_device_list_lock);
880 list_add(&desc->device_list, &wdm_device_list);
881 spin_unlock(&wdm_device_list_lock);
882
883 rv = usb_register_dev(intf, &wdm_class);
884 if (rv < 0)
885 goto err;
886 else
887 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
888out:
889 return rv;
890err:
891 spin_lock(&wdm_device_list_lock);
892 list_del(&desc->device_list);
893 spin_unlock(&wdm_device_list_lock);
894 cleanup(desc);
895 return rv;
896}
897
898static int wdm_manage_power(struct usb_interface *intf, int on)
899{
900 /* need autopm_get/put here to ensure the usbcore sees the new value */
901 int rv = usb_autopm_get_interface(intf);
902
903 intf->needs_remote_wakeup = on;
904 if (!rv)
905 usb_autopm_put_interface(intf);
906 return 0;
907}
908
909static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
910{
911 int rv = -EINVAL;
912 struct usb_host_interface *iface;
913 struct usb_endpoint_descriptor *ep;
914 struct usb_cdc_parsed_header hdr;
915 u8 *buffer = intf->altsetting->extra;
916 int buflen = intf->altsetting->extralen;
917 u16 maxcom = WDM_DEFAULT_BUFSIZE;
918
919 if (!buffer)
920 goto err;
921
922 cdc_parse_cdc_header(&hdr, intf, buffer, buflen);
923
924 if (hdr.usb_cdc_dmm_desc)
925 maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand);
926
927 iface = intf->cur_altsetting;
928 if (iface->desc.bNumEndpoints != 1)
929 goto err;
930 ep = &iface->endpoint[0].desc;
931
932 rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
933
934err:
935 return rv;
936}
937
938/**
939 * usb_cdc_wdm_register - register a WDM subdriver
940 * @intf: usb interface the subdriver will associate with
941 * @ep: interrupt endpoint to monitor for notifications
942 * @bufsize: maximum message size to support for read/write
943 * @manage_power: call-back invoked during open and release to
944 * manage the device's power
945 * Create WDM usb class character device and associate it with intf
946 * without binding, allowing another driver to manage the interface.
947 *
948 * The subdriver will manage the given interrupt endpoint exclusively
949 * and will issue control requests referring to the given intf. It
950 * will otherwise avoid interferring, and in particular not do
951 * usb_set_intfdata/usb_get_intfdata on intf.
952 *
953 * The return value is a pointer to the subdriver's struct usb_driver.
954 * The registering driver is responsible for calling this subdriver's
955 * disconnect, suspend, resume, pre_reset and post_reset methods from
956 * its own.
957 */
958struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
959 struct usb_endpoint_descriptor *ep,
960 int bufsize,
961 int (*manage_power)(struct usb_interface *, int))
962{
963 int rv;
964
965 rv = wdm_create(intf, ep, bufsize, manage_power);
966 if (rv < 0)
967 goto err;
968
969 return &wdm_driver;
970err:
971 return ERR_PTR(rv);
972}
973EXPORT_SYMBOL(usb_cdc_wdm_register);
974
975static void wdm_disconnect(struct usb_interface *intf)
976{
977 struct wdm_device *desc;
978 unsigned long flags;
979
980 usb_deregister_dev(intf, &wdm_class);
981 desc = wdm_find_device(intf);
982 mutex_lock(&wdm_mutex);
983
984 /* the spinlock makes sure no new urbs are generated in the callbacks */
985 spin_lock_irqsave(&desc->iuspin, flags);
986 set_bit(WDM_DISCONNECTING, &desc->flags);
987 set_bit(WDM_READ, &desc->flags);
988 spin_unlock_irqrestore(&desc->iuspin, flags);
989 wake_up_all(&desc->wait);
990 mutex_lock(&desc->rlock);
991 mutex_lock(&desc->wlock);
992 kill_urbs(desc);
993 cancel_work_sync(&desc->rxwork);
994 cancel_work_sync(&desc->service_outs_intr);
995 mutex_unlock(&desc->wlock);
996 mutex_unlock(&desc->rlock);
997
998 /* the desc->intf pointer used as list key is now invalid */
999 spin_lock(&wdm_device_list_lock);
1000 list_del(&desc->device_list);
1001 spin_unlock(&wdm_device_list_lock);
1002
1003 if (!desc->count)
1004 cleanup(desc);
1005 else
1006 dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count);
1007 mutex_unlock(&wdm_mutex);
1008}
1009
1010#ifdef CONFIG_PM
1011static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
1012{
1013 struct wdm_device *desc = wdm_find_device(intf);
1014 int rv = 0;
1015
1016 dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
1017
1018 /* if this is an autosuspend the caller does the locking */
1019 if (!PMSG_IS_AUTO(message)) {
1020 mutex_lock(&desc->rlock);
1021 mutex_lock(&desc->wlock);
1022 }
1023 spin_lock_irq(&desc->iuspin);
1024
1025 if (PMSG_IS_AUTO(message) &&
1026 (test_bit(WDM_IN_USE, &desc->flags)
1027 || test_bit(WDM_RESPONDING, &desc->flags))) {
1028 spin_unlock_irq(&desc->iuspin);
1029 rv = -EBUSY;
1030 } else {
1031
1032 set_bit(WDM_SUSPENDING, &desc->flags);
1033 spin_unlock_irq(&desc->iuspin);
1034 /* callback submits work - order is essential */
1035 kill_urbs(desc);
1036 cancel_work_sync(&desc->rxwork);
1037 cancel_work_sync(&desc->service_outs_intr);
1038 }
1039 if (!PMSG_IS_AUTO(message)) {
1040 mutex_unlock(&desc->wlock);
1041 mutex_unlock(&desc->rlock);
1042 }
1043
1044 return rv;
1045}
1046#endif
1047
1048static int recover_from_urb_loss(struct wdm_device *desc)
1049{
1050 int rv = 0;
1051
1052 if (desc->count) {
1053 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1054 if (rv < 0)
1055 dev_err(&desc->intf->dev,
1056 "Error resume submitting int urb - %d\n", rv);
1057 }
1058 return rv;
1059}
1060
1061#ifdef CONFIG_PM
1062static int wdm_resume(struct usb_interface *intf)
1063{
1064 struct wdm_device *desc = wdm_find_device(intf);
1065 int rv;
1066
1067 dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1068
1069 clear_bit(WDM_SUSPENDING, &desc->flags);
1070 rv = recover_from_urb_loss(desc);
1071
1072 return rv;
1073}
1074#endif
1075
1076static int wdm_pre_reset(struct usb_interface *intf)
1077{
1078 struct wdm_device *desc = wdm_find_device(intf);
1079
1080 /*
1081 * we notify everybody using poll of
1082 * an exceptional situation
1083 * must be done before recovery lest a spontaneous
1084 * message from the device is lost
1085 */
1086 spin_lock_irq(&desc->iuspin);
1087 set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */
1088 set_bit(WDM_READ, &desc->flags); /* unblock read */
1089 clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */
1090 desc->rerr = -EINTR;
1091 spin_unlock_irq(&desc->iuspin);
1092 wake_up_all(&desc->wait);
1093 mutex_lock(&desc->rlock);
1094 mutex_lock(&desc->wlock);
1095 kill_urbs(desc);
1096 cancel_work_sync(&desc->rxwork);
1097 cancel_work_sync(&desc->service_outs_intr);
1098 return 0;
1099}
1100
1101static int wdm_post_reset(struct usb_interface *intf)
1102{
1103 struct wdm_device *desc = wdm_find_device(intf);
1104 int rv;
1105
1106 clear_bit(WDM_OVERFLOW, &desc->flags);
1107 clear_bit(WDM_RESETTING, &desc->flags);
1108 rv = recover_from_urb_loss(desc);
1109 mutex_unlock(&desc->wlock);
1110 mutex_unlock(&desc->rlock);
1111 return rv;
1112}
1113
1114static struct usb_driver wdm_driver = {
1115 .name = "cdc_wdm",
1116 .probe = wdm_probe,
1117 .disconnect = wdm_disconnect,
1118#ifdef CONFIG_PM
1119 .suspend = wdm_suspend,
1120 .resume = wdm_resume,
1121 .reset_resume = wdm_resume,
1122#endif
1123 .pre_reset = wdm_pre_reset,
1124 .post_reset = wdm_post_reset,
1125 .id_table = wdm_ids,
1126 .supports_autosuspend = 1,
1127 .disable_hub_initiated_lpm = 1,
1128};
1129
1130module_usb_driver(wdm_driver);
1131
1132MODULE_AUTHOR(DRIVER_AUTHOR);
1133MODULE_DESCRIPTION(DRIVER_DESC);
1134MODULE_LICENSE("GPL");
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/usb.h>
25#include <linux/usb/cdc.h>
26#include <asm/byteorder.h>
27#include <asm/unaligned.h>
28#include <linux/usb/cdc-wdm.h>
29
30#define DRIVER_AUTHOR "Oliver Neukum"
31#define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
32
33static const struct usb_device_id wdm_ids[] = {
34 {
35 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
36 USB_DEVICE_ID_MATCH_INT_SUBCLASS,
37 .bInterfaceClass = USB_CLASS_COMM,
38 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
39 },
40 { }
41};
42
43MODULE_DEVICE_TABLE (usb, wdm_ids);
44
45#define WDM_MINOR_BASE 176
46
47
48#define WDM_IN_USE 1
49#define WDM_DISCONNECTING 2
50#define WDM_RESULT 3
51#define WDM_READ 4
52#define WDM_INT_STALL 5
53#define WDM_POLL_RUNNING 6
54#define WDM_RESPONDING 7
55#define WDM_SUSPENDING 8
56#define WDM_RESETTING 9
57#define WDM_OVERFLOW 10
58
59#define WDM_MAX 16
60
61/* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
62#define WDM_DEFAULT_BUFSIZE 256
63
64static DEFINE_MUTEX(wdm_mutex);
65static DEFINE_SPINLOCK(wdm_device_list_lock);
66static LIST_HEAD(wdm_device_list);
67
68/* --- method tables --- */
69
70struct wdm_device {
71 u8 *inbuf; /* buffer for response */
72 u8 *outbuf; /* buffer for command */
73 u8 *sbuf; /* buffer for status */
74 u8 *ubuf; /* buffer for copy to user space */
75
76 struct urb *command;
77 struct urb *response;
78 struct urb *validity;
79 struct usb_interface *intf;
80 struct usb_ctrlrequest *orq;
81 struct usb_ctrlrequest *irq;
82 spinlock_t iuspin;
83
84 unsigned long flags;
85 u16 bufsize;
86 u16 wMaxCommand;
87 u16 wMaxPacketSize;
88 __le16 inum;
89 int reslength;
90 int length;
91 int read;
92 int count;
93 dma_addr_t shandle;
94 dma_addr_t ihandle;
95 struct mutex wlock;
96 struct mutex rlock;
97 wait_queue_head_t wait;
98 struct work_struct rxwork;
99 int werr;
100 int rerr;
101 int resp_count;
102
103 struct list_head device_list;
104 int (*manage_power)(struct usb_interface *, int);
105};
106
107static struct usb_driver wdm_driver;
108
109/* return intfdata if we own the interface, else look up intf in the list */
110static struct wdm_device *wdm_find_device(struct usb_interface *intf)
111{
112 struct wdm_device *desc;
113
114 spin_lock(&wdm_device_list_lock);
115 list_for_each_entry(desc, &wdm_device_list, device_list)
116 if (desc->intf == intf)
117 goto found;
118 desc = NULL;
119found:
120 spin_unlock(&wdm_device_list_lock);
121
122 return desc;
123}
124
125static struct wdm_device *wdm_find_device_by_minor(int minor)
126{
127 struct wdm_device *desc;
128
129 spin_lock(&wdm_device_list_lock);
130 list_for_each_entry(desc, &wdm_device_list, device_list)
131 if (desc->intf->minor == minor)
132 goto found;
133 desc = NULL;
134found:
135 spin_unlock(&wdm_device_list_lock);
136
137 return desc;
138}
139
140/* --- callbacks --- */
141static void wdm_out_callback(struct urb *urb)
142{
143 struct wdm_device *desc;
144 desc = urb->context;
145 spin_lock(&desc->iuspin);
146 desc->werr = urb->status;
147 spin_unlock(&desc->iuspin);
148 kfree(desc->outbuf);
149 desc->outbuf = NULL;
150 clear_bit(WDM_IN_USE, &desc->flags);
151 wake_up(&desc->wait);
152}
153
154/* forward declaration */
155static int service_outstanding_interrupt(struct wdm_device *desc);
156
157static void wdm_in_callback(struct urb *urb)
158{
159 struct wdm_device *desc = urb->context;
160 int status = urb->status;
161 int length = urb->actual_length;
162
163 spin_lock(&desc->iuspin);
164 clear_bit(WDM_RESPONDING, &desc->flags);
165
166 if (status) {
167 switch (status) {
168 case -ENOENT:
169 dev_dbg(&desc->intf->dev,
170 "nonzero urb status received: -ENOENT\n");
171 goto skip_error;
172 case -ECONNRESET:
173 dev_dbg(&desc->intf->dev,
174 "nonzero urb status received: -ECONNRESET\n");
175 goto skip_error;
176 case -ESHUTDOWN:
177 dev_dbg(&desc->intf->dev,
178 "nonzero urb status received: -ESHUTDOWN\n");
179 goto skip_error;
180 case -EPIPE:
181 dev_err(&desc->intf->dev,
182 "nonzero urb status received: -EPIPE\n");
183 break;
184 default:
185 dev_err(&desc->intf->dev,
186 "Unexpected error %d\n", status);
187 break;
188 }
189 }
190
191 /*
192 * only set a new error if there is no previous error.
193 * Errors are only cleared during read/open
194 * Avoid propagating -EPIPE (stall) to userspace since it is
195 * better handled as an empty read
196 */
197 if (desc->rerr == 0 && status != -EPIPE)
198 desc->rerr = status;
199
200 if (length + desc->length > desc->wMaxCommand) {
201 /* The buffer would overflow */
202 set_bit(WDM_OVERFLOW, &desc->flags);
203 } else {
204 /* we may already be in overflow */
205 if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
206 memmove(desc->ubuf + desc->length, desc->inbuf, length);
207 desc->length += length;
208 desc->reslength = length;
209 }
210 }
211skip_error:
212 set_bit(WDM_READ, &desc->flags);
213 wake_up(&desc->wait);
214
215 if (desc->rerr) {
216 /*
217 * Since there was an error, userspace may decide to not read
218 * any data after poll'ing.
219 * We should respond to further attempts from the device to send
220 * data, so that we can get unstuck.
221 */
222 service_outstanding_interrupt(desc);
223 }
224
225 spin_unlock(&desc->iuspin);
226}
227
228static void wdm_int_callback(struct urb *urb)
229{
230 int rv = 0;
231 int responding;
232 int status = urb->status;
233 struct wdm_device *desc;
234 struct usb_cdc_notification *dr;
235
236 desc = urb->context;
237 dr = (struct usb_cdc_notification *)desc->sbuf;
238
239 if (status) {
240 switch (status) {
241 case -ESHUTDOWN:
242 case -ENOENT:
243 case -ECONNRESET:
244 return; /* unplug */
245 case -EPIPE:
246 set_bit(WDM_INT_STALL, &desc->flags);
247 dev_err(&desc->intf->dev, "Stall on int endpoint\n");
248 goto sw; /* halt is cleared in work */
249 default:
250 dev_err(&desc->intf->dev,
251 "nonzero urb status received: %d\n", status);
252 break;
253 }
254 }
255
256 if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
257 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
258 urb->actual_length);
259 goto exit;
260 }
261
262 switch (dr->bNotificationType) {
263 case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
264 dev_dbg(&desc->intf->dev,
265 "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d\n",
266 le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength));
267 break;
268
269 case USB_CDC_NOTIFY_NETWORK_CONNECTION:
270
271 dev_dbg(&desc->intf->dev,
272 "NOTIFY_NETWORK_CONNECTION %s network\n",
273 dr->wValue ? "connected to" : "disconnected from");
274 goto exit;
275 case USB_CDC_NOTIFY_SPEED_CHANGE:
276 dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)\n",
277 urb->actual_length);
278 goto exit;
279 default:
280 clear_bit(WDM_POLL_RUNNING, &desc->flags);
281 dev_err(&desc->intf->dev,
282 "unknown notification %d received: index %d len %d\n",
283 dr->bNotificationType,
284 le16_to_cpu(dr->wIndex),
285 le16_to_cpu(dr->wLength));
286 goto exit;
287 }
288
289 spin_lock(&desc->iuspin);
290 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
291 if (!desc->resp_count++ && !responding
292 && !test_bit(WDM_DISCONNECTING, &desc->flags)
293 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
294 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
295 dev_dbg(&desc->intf->dev, "submit response URB %d\n", rv);
296 }
297 spin_unlock(&desc->iuspin);
298 if (rv < 0) {
299 clear_bit(WDM_RESPONDING, &desc->flags);
300 if (rv == -EPERM)
301 return;
302 if (rv == -ENOMEM) {
303sw:
304 rv = schedule_work(&desc->rxwork);
305 if (rv)
306 dev_err(&desc->intf->dev,
307 "Cannot schedule work\n");
308 }
309 }
310exit:
311 rv = usb_submit_urb(urb, GFP_ATOMIC);
312 if (rv)
313 dev_err(&desc->intf->dev,
314 "%s - usb_submit_urb failed with result %d\n",
315 __func__, rv);
316
317}
318
319static void kill_urbs(struct wdm_device *desc)
320{
321 /* the order here is essential */
322 usb_kill_urb(desc->command);
323 usb_kill_urb(desc->validity);
324 usb_kill_urb(desc->response);
325}
326
327static void free_urbs(struct wdm_device *desc)
328{
329 usb_free_urb(desc->validity);
330 usb_free_urb(desc->response);
331 usb_free_urb(desc->command);
332}
333
334static void cleanup(struct wdm_device *desc)
335{
336 kfree(desc->sbuf);
337 kfree(desc->inbuf);
338 kfree(desc->orq);
339 kfree(desc->irq);
340 kfree(desc->ubuf);
341 free_urbs(desc);
342 kfree(desc);
343}
344
345static ssize_t wdm_write
346(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
347{
348 u8 *buf;
349 int rv = -EMSGSIZE, r, we;
350 struct wdm_device *desc = file->private_data;
351 struct usb_ctrlrequest *req;
352
353 if (count > desc->wMaxCommand)
354 count = desc->wMaxCommand;
355
356 spin_lock_irq(&desc->iuspin);
357 we = desc->werr;
358 desc->werr = 0;
359 spin_unlock_irq(&desc->iuspin);
360 if (we < 0)
361 return usb_translate_errors(we);
362
363 buf = memdup_user(buffer, count);
364 if (IS_ERR(buf))
365 return PTR_ERR(buf);
366
367 /* concurrent writes and disconnect */
368 r = mutex_lock_interruptible(&desc->wlock);
369 rv = -ERESTARTSYS;
370 if (r)
371 goto out_free_mem;
372
373 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
374 rv = -ENODEV;
375 goto out_free_mem_lock;
376 }
377
378 r = usb_autopm_get_interface(desc->intf);
379 if (r < 0) {
380 rv = usb_translate_errors(r);
381 goto out_free_mem_lock;
382 }
383
384 if (!(file->f_flags & O_NONBLOCK))
385 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
386 &desc->flags));
387 else
388 if (test_bit(WDM_IN_USE, &desc->flags))
389 r = -EAGAIN;
390
391 if (test_bit(WDM_RESETTING, &desc->flags))
392 r = -EIO;
393
394 if (r < 0) {
395 rv = r;
396 goto out_free_mem_pm;
397 }
398
399 req = desc->orq;
400 usb_fill_control_urb(
401 desc->command,
402 interface_to_usbdev(desc->intf),
403 /* using common endpoint 0 */
404 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
405 (unsigned char *)req,
406 buf,
407 count,
408 wdm_out_callback,
409 desc
410 );
411
412 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
413 USB_RECIP_INTERFACE);
414 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
415 req->wValue = 0;
416 req->wIndex = desc->inum; /* already converted */
417 req->wLength = cpu_to_le16(count);
418 set_bit(WDM_IN_USE, &desc->flags);
419 desc->outbuf = buf;
420
421 rv = usb_submit_urb(desc->command, GFP_KERNEL);
422 if (rv < 0) {
423 desc->outbuf = NULL;
424 clear_bit(WDM_IN_USE, &desc->flags);
425 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
426 rv = usb_translate_errors(rv);
427 goto out_free_mem_pm;
428 } else {
429 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d\n",
430 le16_to_cpu(req->wIndex));
431 }
432
433 usb_autopm_put_interface(desc->intf);
434 mutex_unlock(&desc->wlock);
435 return count;
436
437out_free_mem_pm:
438 usb_autopm_put_interface(desc->intf);
439out_free_mem_lock:
440 mutex_unlock(&desc->wlock);
441out_free_mem:
442 kfree(buf);
443 return rv;
444}
445
446/*
447 * Submit the read urb if resp_count is non-zero.
448 *
449 * Called with desc->iuspin locked
450 */
451static int service_outstanding_interrupt(struct wdm_device *desc)
452{
453 int rv = 0;
454
455 /* submit read urb only if the device is waiting for it */
456 if (!desc->resp_count || !--desc->resp_count)
457 goto out;
458
459 set_bit(WDM_RESPONDING, &desc->flags);
460 spin_unlock_irq(&desc->iuspin);
461 rv = usb_submit_urb(desc->response, GFP_KERNEL);
462 spin_lock_irq(&desc->iuspin);
463 if (rv) {
464 dev_err(&desc->intf->dev,
465 "usb_submit_urb failed with result %d\n", rv);
466
467 /* make sure the next notification trigger a submit */
468 clear_bit(WDM_RESPONDING, &desc->flags);
469 desc->resp_count = 0;
470 }
471out:
472 return rv;
473}
474
475static ssize_t wdm_read
476(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
477{
478 int rv, cntr;
479 int i = 0;
480 struct wdm_device *desc = file->private_data;
481
482
483 rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
484 if (rv < 0)
485 return -ERESTARTSYS;
486
487 cntr = READ_ONCE(desc->length);
488 if (cntr == 0) {
489 desc->read = 0;
490retry:
491 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
492 rv = -ENODEV;
493 goto err;
494 }
495 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
496 clear_bit(WDM_OVERFLOW, &desc->flags);
497 rv = -ENOBUFS;
498 goto err;
499 }
500 i++;
501 if (file->f_flags & O_NONBLOCK) {
502 if (!test_bit(WDM_READ, &desc->flags)) {
503 rv = -EAGAIN;
504 goto err;
505 }
506 rv = 0;
507 } else {
508 rv = wait_event_interruptible(desc->wait,
509 test_bit(WDM_READ, &desc->flags));
510 }
511
512 /* may have happened while we slept */
513 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
514 rv = -ENODEV;
515 goto err;
516 }
517 if (test_bit(WDM_RESETTING, &desc->flags)) {
518 rv = -EIO;
519 goto err;
520 }
521 usb_mark_last_busy(interface_to_usbdev(desc->intf));
522 if (rv < 0) {
523 rv = -ERESTARTSYS;
524 goto err;
525 }
526
527 spin_lock_irq(&desc->iuspin);
528
529 if (desc->rerr) { /* read completed, error happened */
530 rv = usb_translate_errors(desc->rerr);
531 desc->rerr = 0;
532 spin_unlock_irq(&desc->iuspin);
533 goto err;
534 }
535 /*
536 * recheck whether we've lost the race
537 * against the completion handler
538 */
539 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
540 spin_unlock_irq(&desc->iuspin);
541 goto retry;
542 }
543
544 if (!desc->reslength) { /* zero length read */
545 dev_dbg(&desc->intf->dev, "zero length - clearing WDM_READ\n");
546 clear_bit(WDM_READ, &desc->flags);
547 rv = service_outstanding_interrupt(desc);
548 spin_unlock_irq(&desc->iuspin);
549 if (rv < 0)
550 goto err;
551 goto retry;
552 }
553 cntr = desc->length;
554 spin_unlock_irq(&desc->iuspin);
555 }
556
557 if (cntr > count)
558 cntr = count;
559 rv = copy_to_user(buffer, desc->ubuf, cntr);
560 if (rv > 0) {
561 rv = -EFAULT;
562 goto err;
563 }
564
565 spin_lock_irq(&desc->iuspin);
566
567 for (i = 0; i < desc->length - cntr; i++)
568 desc->ubuf[i] = desc->ubuf[i + cntr];
569
570 desc->length -= cntr;
571 /* in case we had outstanding data */
572 if (!desc->length) {
573 clear_bit(WDM_READ, &desc->flags);
574 service_outstanding_interrupt(desc);
575 }
576 spin_unlock_irq(&desc->iuspin);
577 rv = cntr;
578
579err:
580 mutex_unlock(&desc->rlock);
581 return rv;
582}
583
584static int wdm_flush(struct file *file, fl_owner_t id)
585{
586 struct wdm_device *desc = file->private_data;
587
588 wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
589
590 /* cannot dereference desc->intf if WDM_DISCONNECTING */
591 if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
592 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
593 desc->werr);
594
595 return usb_translate_errors(desc->werr);
596}
597
598static __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait)
599{
600 struct wdm_device *desc = file->private_data;
601 unsigned long flags;
602 __poll_t mask = 0;
603
604 spin_lock_irqsave(&desc->iuspin, flags);
605 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
606 mask = EPOLLHUP | EPOLLERR;
607 spin_unlock_irqrestore(&desc->iuspin, flags);
608 goto desc_out;
609 }
610 if (test_bit(WDM_READ, &desc->flags))
611 mask = EPOLLIN | EPOLLRDNORM;
612 if (desc->rerr || desc->werr)
613 mask |= EPOLLERR;
614 if (!test_bit(WDM_IN_USE, &desc->flags))
615 mask |= EPOLLOUT | EPOLLWRNORM;
616 spin_unlock_irqrestore(&desc->iuspin, flags);
617
618 poll_wait(file, &desc->wait, wait);
619
620desc_out:
621 return mask;
622}
623
624static int wdm_open(struct inode *inode, struct file *file)
625{
626 int minor = iminor(inode);
627 int rv = -ENODEV;
628 struct usb_interface *intf;
629 struct wdm_device *desc;
630
631 mutex_lock(&wdm_mutex);
632 desc = wdm_find_device_by_minor(minor);
633 if (!desc)
634 goto out;
635
636 intf = desc->intf;
637 if (test_bit(WDM_DISCONNECTING, &desc->flags))
638 goto out;
639 file->private_data = desc;
640
641 rv = usb_autopm_get_interface(desc->intf);
642 if (rv < 0) {
643 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
644 goto out;
645 }
646
647 /* using write lock to protect desc->count */
648 mutex_lock(&desc->wlock);
649 if (!desc->count++) {
650 desc->werr = 0;
651 desc->rerr = 0;
652 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
653 if (rv < 0) {
654 desc->count--;
655 dev_err(&desc->intf->dev,
656 "Error submitting int urb - %d\n", rv);
657 rv = usb_translate_errors(rv);
658 }
659 } else {
660 rv = 0;
661 }
662 mutex_unlock(&desc->wlock);
663 if (desc->count == 1)
664 desc->manage_power(intf, 1);
665 usb_autopm_put_interface(desc->intf);
666out:
667 mutex_unlock(&wdm_mutex);
668 return rv;
669}
670
671static int wdm_release(struct inode *inode, struct file *file)
672{
673 struct wdm_device *desc = file->private_data;
674
675 mutex_lock(&wdm_mutex);
676
677 /* using write lock to protect desc->count */
678 mutex_lock(&desc->wlock);
679 desc->count--;
680 mutex_unlock(&desc->wlock);
681
682 if (!desc->count) {
683 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
684 dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n");
685 kill_urbs(desc);
686 spin_lock_irq(&desc->iuspin);
687 desc->resp_count = 0;
688 spin_unlock_irq(&desc->iuspin);
689 desc->manage_power(desc->intf, 0);
690 } else {
691 /* must avoid dev_printk here as desc->intf is invalid */
692 pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
693 cleanup(desc);
694 }
695 }
696 mutex_unlock(&wdm_mutex);
697 return 0;
698}
699
700static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
701{
702 struct wdm_device *desc = file->private_data;
703 int rv = 0;
704
705 switch (cmd) {
706 case IOCTL_WDM_MAX_COMMAND:
707 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
708 rv = -EFAULT;
709 break;
710 default:
711 rv = -ENOTTY;
712 }
713 return rv;
714}
715
716static const struct file_operations wdm_fops = {
717 .owner = THIS_MODULE,
718 .read = wdm_read,
719 .write = wdm_write,
720 .open = wdm_open,
721 .flush = wdm_flush,
722 .release = wdm_release,
723 .poll = wdm_poll,
724 .unlocked_ioctl = wdm_ioctl,
725 .compat_ioctl = wdm_ioctl,
726 .llseek = noop_llseek,
727};
728
729static struct usb_class_driver wdm_class = {
730 .name = "cdc-wdm%d",
731 .fops = &wdm_fops,
732 .minor_base = WDM_MINOR_BASE,
733};
734
735/* --- error handling --- */
736static void wdm_rxwork(struct work_struct *work)
737{
738 struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
739 unsigned long flags;
740 int rv = 0;
741 int responding;
742
743 spin_lock_irqsave(&desc->iuspin, flags);
744 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
745 spin_unlock_irqrestore(&desc->iuspin, flags);
746 } else {
747 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
748 spin_unlock_irqrestore(&desc->iuspin, flags);
749 if (!responding)
750 rv = usb_submit_urb(desc->response, GFP_KERNEL);
751 if (rv < 0 && rv != -EPERM) {
752 spin_lock_irqsave(&desc->iuspin, flags);
753 clear_bit(WDM_RESPONDING, &desc->flags);
754 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
755 schedule_work(&desc->rxwork);
756 spin_unlock_irqrestore(&desc->iuspin, flags);
757 }
758 }
759}
760
761/* --- hotplug --- */
762
763static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
764 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
765{
766 int rv = -ENOMEM;
767 struct wdm_device *desc;
768
769 desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
770 if (!desc)
771 goto out;
772 INIT_LIST_HEAD(&desc->device_list);
773 mutex_init(&desc->rlock);
774 mutex_init(&desc->wlock);
775 spin_lock_init(&desc->iuspin);
776 init_waitqueue_head(&desc->wait);
777 desc->wMaxCommand = bufsize;
778 /* this will be expanded and needed in hardware endianness */
779 desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
780 desc->intf = intf;
781 INIT_WORK(&desc->rxwork, wdm_rxwork);
782
783 rv = -EINVAL;
784 if (!usb_endpoint_is_int_in(ep))
785 goto err;
786
787 desc->wMaxPacketSize = usb_endpoint_maxp(ep);
788
789 desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
790 if (!desc->orq)
791 goto err;
792 desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
793 if (!desc->irq)
794 goto err;
795
796 desc->validity = usb_alloc_urb(0, GFP_KERNEL);
797 if (!desc->validity)
798 goto err;
799
800 desc->response = usb_alloc_urb(0, GFP_KERNEL);
801 if (!desc->response)
802 goto err;
803
804 desc->command = usb_alloc_urb(0, GFP_KERNEL);
805 if (!desc->command)
806 goto err;
807
808 desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
809 if (!desc->ubuf)
810 goto err;
811
812 desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
813 if (!desc->sbuf)
814 goto err;
815
816 desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
817 if (!desc->inbuf)
818 goto err;
819
820 usb_fill_int_urb(
821 desc->validity,
822 interface_to_usbdev(intf),
823 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
824 desc->sbuf,
825 desc->wMaxPacketSize,
826 wdm_int_callback,
827 desc,
828 ep->bInterval
829 );
830
831 desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
832 desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
833 desc->irq->wValue = 0;
834 desc->irq->wIndex = desc->inum; /* already converted */
835 desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
836
837 usb_fill_control_urb(
838 desc->response,
839 interface_to_usbdev(intf),
840 /* using common endpoint 0 */
841 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
842 (unsigned char *)desc->irq,
843 desc->inbuf,
844 desc->wMaxCommand,
845 wdm_in_callback,
846 desc
847 );
848
849 desc->manage_power = manage_power;
850
851 spin_lock(&wdm_device_list_lock);
852 list_add(&desc->device_list, &wdm_device_list);
853 spin_unlock(&wdm_device_list_lock);
854
855 rv = usb_register_dev(intf, &wdm_class);
856 if (rv < 0)
857 goto err;
858 else
859 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
860out:
861 return rv;
862err:
863 spin_lock(&wdm_device_list_lock);
864 list_del(&desc->device_list);
865 spin_unlock(&wdm_device_list_lock);
866 cleanup(desc);
867 return rv;
868}
869
870static int wdm_manage_power(struct usb_interface *intf, int on)
871{
872 /* need autopm_get/put here to ensure the usbcore sees the new value */
873 int rv = usb_autopm_get_interface(intf);
874
875 intf->needs_remote_wakeup = on;
876 if (!rv)
877 usb_autopm_put_interface(intf);
878 return 0;
879}
880
881static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
882{
883 int rv = -EINVAL;
884 struct usb_host_interface *iface;
885 struct usb_endpoint_descriptor *ep;
886 struct usb_cdc_parsed_header hdr;
887 u8 *buffer = intf->altsetting->extra;
888 int buflen = intf->altsetting->extralen;
889 u16 maxcom = WDM_DEFAULT_BUFSIZE;
890
891 if (!buffer)
892 goto err;
893
894 cdc_parse_cdc_header(&hdr, intf, buffer, buflen);
895
896 if (hdr.usb_cdc_dmm_desc)
897 maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand);
898
899 iface = intf->cur_altsetting;
900 if (iface->desc.bNumEndpoints != 1)
901 goto err;
902 ep = &iface->endpoint[0].desc;
903
904 rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
905
906err:
907 return rv;
908}
909
910/**
911 * usb_cdc_wdm_register - register a WDM subdriver
912 * @intf: usb interface the subdriver will associate with
913 * @ep: interrupt endpoint to monitor for notifications
914 * @bufsize: maximum message size to support for read/write
915 *
916 * Create WDM usb class character device and associate it with intf
917 * without binding, allowing another driver to manage the interface.
918 *
919 * The subdriver will manage the given interrupt endpoint exclusively
920 * and will issue control requests referring to the given intf. It
921 * will otherwise avoid interferring, and in particular not do
922 * usb_set_intfdata/usb_get_intfdata on intf.
923 *
924 * The return value is a pointer to the subdriver's struct usb_driver.
925 * The registering driver is responsible for calling this subdriver's
926 * disconnect, suspend, resume, pre_reset and post_reset methods from
927 * its own.
928 */
929struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
930 struct usb_endpoint_descriptor *ep,
931 int bufsize,
932 int (*manage_power)(struct usb_interface *, int))
933{
934 int rv = -EINVAL;
935
936 rv = wdm_create(intf, ep, bufsize, manage_power);
937 if (rv < 0)
938 goto err;
939
940 return &wdm_driver;
941err:
942 return ERR_PTR(rv);
943}
944EXPORT_SYMBOL(usb_cdc_wdm_register);
945
946static void wdm_disconnect(struct usb_interface *intf)
947{
948 struct wdm_device *desc;
949 unsigned long flags;
950
951 usb_deregister_dev(intf, &wdm_class);
952 desc = wdm_find_device(intf);
953 mutex_lock(&wdm_mutex);
954
955 /* the spinlock makes sure no new urbs are generated in the callbacks */
956 spin_lock_irqsave(&desc->iuspin, flags);
957 set_bit(WDM_DISCONNECTING, &desc->flags);
958 set_bit(WDM_READ, &desc->flags);
959 /* to terminate pending flushes */
960 clear_bit(WDM_IN_USE, &desc->flags);
961 spin_unlock_irqrestore(&desc->iuspin, flags);
962 wake_up_all(&desc->wait);
963 mutex_lock(&desc->rlock);
964 mutex_lock(&desc->wlock);
965 kill_urbs(desc);
966 cancel_work_sync(&desc->rxwork);
967 mutex_unlock(&desc->wlock);
968 mutex_unlock(&desc->rlock);
969
970 /* the desc->intf pointer used as list key is now invalid */
971 spin_lock(&wdm_device_list_lock);
972 list_del(&desc->device_list);
973 spin_unlock(&wdm_device_list_lock);
974
975 if (!desc->count)
976 cleanup(desc);
977 else
978 dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count);
979 mutex_unlock(&wdm_mutex);
980}
981
982#ifdef CONFIG_PM
983static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
984{
985 struct wdm_device *desc = wdm_find_device(intf);
986 int rv = 0;
987
988 dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
989
990 /* if this is an autosuspend the caller does the locking */
991 if (!PMSG_IS_AUTO(message)) {
992 mutex_lock(&desc->rlock);
993 mutex_lock(&desc->wlock);
994 }
995 spin_lock_irq(&desc->iuspin);
996
997 if (PMSG_IS_AUTO(message) &&
998 (test_bit(WDM_IN_USE, &desc->flags)
999 || test_bit(WDM_RESPONDING, &desc->flags))) {
1000 spin_unlock_irq(&desc->iuspin);
1001 rv = -EBUSY;
1002 } else {
1003
1004 set_bit(WDM_SUSPENDING, &desc->flags);
1005 spin_unlock_irq(&desc->iuspin);
1006 /* callback submits work - order is essential */
1007 kill_urbs(desc);
1008 cancel_work_sync(&desc->rxwork);
1009 }
1010 if (!PMSG_IS_AUTO(message)) {
1011 mutex_unlock(&desc->wlock);
1012 mutex_unlock(&desc->rlock);
1013 }
1014
1015 return rv;
1016}
1017#endif
1018
1019static int recover_from_urb_loss(struct wdm_device *desc)
1020{
1021 int rv = 0;
1022
1023 if (desc->count) {
1024 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1025 if (rv < 0)
1026 dev_err(&desc->intf->dev,
1027 "Error resume submitting int urb - %d\n", rv);
1028 }
1029 return rv;
1030}
1031
1032#ifdef CONFIG_PM
1033static int wdm_resume(struct usb_interface *intf)
1034{
1035 struct wdm_device *desc = wdm_find_device(intf);
1036 int rv;
1037
1038 dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1039
1040 clear_bit(WDM_SUSPENDING, &desc->flags);
1041 rv = recover_from_urb_loss(desc);
1042
1043 return rv;
1044}
1045#endif
1046
1047static int wdm_pre_reset(struct usb_interface *intf)
1048{
1049 struct wdm_device *desc = wdm_find_device(intf);
1050
1051 /*
1052 * we notify everybody using poll of
1053 * an exceptional situation
1054 * must be done before recovery lest a spontaneous
1055 * message from the device is lost
1056 */
1057 spin_lock_irq(&desc->iuspin);
1058 set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */
1059 set_bit(WDM_READ, &desc->flags); /* unblock read */
1060 clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */
1061 desc->rerr = -EINTR;
1062 spin_unlock_irq(&desc->iuspin);
1063 wake_up_all(&desc->wait);
1064 mutex_lock(&desc->rlock);
1065 mutex_lock(&desc->wlock);
1066 kill_urbs(desc);
1067 cancel_work_sync(&desc->rxwork);
1068 return 0;
1069}
1070
1071static int wdm_post_reset(struct usb_interface *intf)
1072{
1073 struct wdm_device *desc = wdm_find_device(intf);
1074 int rv;
1075
1076 clear_bit(WDM_OVERFLOW, &desc->flags);
1077 clear_bit(WDM_RESETTING, &desc->flags);
1078 rv = recover_from_urb_loss(desc);
1079 mutex_unlock(&desc->wlock);
1080 mutex_unlock(&desc->rlock);
1081 return 0;
1082}
1083
1084static struct usb_driver wdm_driver = {
1085 .name = "cdc_wdm",
1086 .probe = wdm_probe,
1087 .disconnect = wdm_disconnect,
1088#ifdef CONFIG_PM
1089 .suspend = wdm_suspend,
1090 .resume = wdm_resume,
1091 .reset_resume = wdm_resume,
1092#endif
1093 .pre_reset = wdm_pre_reset,
1094 .post_reset = wdm_post_reset,
1095 .id_table = wdm_ids,
1096 .supports_autosuspend = 1,
1097 .disable_hub_initiated_lpm = 1,
1098};
1099
1100module_usb_driver(wdm_driver);
1101
1102MODULE_AUTHOR(DRIVER_AUTHOR);
1103MODULE_DESCRIPTION(DRIVER_DESC);
1104MODULE_LICENSE("GPL");