xref: /openbmc/linux/drivers/usb/class/cdc-wdm.c (revision e8e0929d)
1 /*
2  * cdc-wdm.c
3  *
4  * This driver supports USB CDC WCM Device Management.
5  *
6  * Copyright (c) 2007-2009 Oliver Neukum
7  *
8  * Some code taken from cdc-acm.c
9  *
10  * Released under the GPLv2.
11  *
12  * Many thanks to Carl Nordbeck
13  */
14 #include <linux/kernel.h>
15 #include <linux/errno.h>
16 #include <linux/slab.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19 #include <linux/uaccess.h>
20 #include <linux/bitops.h>
21 #include <linux/poll.h>
22 #include <linux/usb.h>
23 #include <linux/usb/cdc.h>
24 #include <asm/byteorder.h>
25 #include <asm/unaligned.h>
26 
27 /*
28  * Version Information
29  */
30 #define DRIVER_VERSION "v0.03"
31 #define DRIVER_AUTHOR "Oliver Neukum"
32 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
33 
34 static struct usb_device_id wdm_ids[] = {
35 	{
36 		.match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
37 				 USB_DEVICE_ID_MATCH_INT_SUBCLASS,
38 		.bInterfaceClass = USB_CLASS_COMM,
39 		.bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
40 	},
41 	{ }
42 };
43 
44 MODULE_DEVICE_TABLE (usb, wdm_ids);
45 
46 #define WDM_MINOR_BASE	176
47 
48 
49 #define WDM_IN_USE		1
50 #define WDM_DISCONNECTING	2
51 #define WDM_RESULT		3
52 #define WDM_READ		4
53 #define WDM_INT_STALL		5
54 #define WDM_POLL_RUNNING	6
55 
56 
57 #define WDM_MAX			16
58 
59 
60 static DEFINE_MUTEX(wdm_mutex);
61 
62 /* --- method tables --- */
63 
64 struct wdm_device {
65 	u8			*inbuf; /* buffer for response */
66 	u8			*outbuf; /* buffer for command */
67 	u8			*sbuf; /* buffer for status */
68 	u8			*ubuf; /* buffer for copy to user space */
69 
70 	struct urb		*command;
71 	struct urb		*response;
72 	struct urb		*validity;
73 	struct usb_interface	*intf;
74 	struct usb_ctrlrequest	*orq;
75 	struct usb_ctrlrequest	*irq;
76 	spinlock_t		iuspin;
77 
78 	unsigned long		flags;
79 	u16			bufsize;
80 	u16			wMaxCommand;
81 	u16			wMaxPacketSize;
82 	u16			bMaxPacketSize0;
83 	__le16			inum;
84 	int			reslength;
85 	int			length;
86 	int			read;
87 	int			count;
88 	dma_addr_t		shandle;
89 	dma_addr_t		ihandle;
90 	struct mutex		wlock;
91 	struct mutex		rlock;
92 	struct mutex		plock;
93 	wait_queue_head_t	wait;
94 	struct work_struct	rxwork;
95 	int			werr;
96 	int			rerr;
97 };
98 
99 static struct usb_driver wdm_driver;
100 
101 /* --- callbacks --- */
102 static void wdm_out_callback(struct urb *urb)
103 {
104 	struct wdm_device *desc;
105 	desc = urb->context;
106 	spin_lock(&desc->iuspin);
107 	desc->werr = urb->status;
108 	spin_unlock(&desc->iuspin);
109 	clear_bit(WDM_IN_USE, &desc->flags);
110 	kfree(desc->outbuf);
111 	wake_up(&desc->wait);
112 }
113 
114 static void wdm_in_callback(struct urb *urb)
115 {
116 	struct wdm_device *desc = urb->context;
117 	int status = urb->status;
118 
119 	spin_lock(&desc->iuspin);
120 
121 	if (status) {
122 		switch (status) {
123 		case -ENOENT:
124 			dev_dbg(&desc->intf->dev,
125 				"nonzero urb status received: -ENOENT");
126 			break;
127 		case -ECONNRESET:
128 			dev_dbg(&desc->intf->dev,
129 				"nonzero urb status received: -ECONNRESET");
130 			break;
131 		case -ESHUTDOWN:
132 			dev_dbg(&desc->intf->dev,
133 				"nonzero urb status received: -ESHUTDOWN");
134 			break;
135 		case -EPIPE:
136 			dev_err(&desc->intf->dev,
137 				"nonzero urb status received: -EPIPE\n");
138 			break;
139 		default:
140 			dev_err(&desc->intf->dev,
141 				"Unexpected error %d\n", status);
142 			break;
143 		}
144 	}
145 
146 	desc->rerr = status;
147 	desc->reslength = urb->actual_length;
148 	memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);
149 	desc->length += desc->reslength;
150 	wake_up(&desc->wait);
151 
152 	set_bit(WDM_READ, &desc->flags);
153 	spin_unlock(&desc->iuspin);
154 }
155 
156 static void wdm_int_callback(struct urb *urb)
157 {
158 	int rv = 0;
159 	int status = urb->status;
160 	struct wdm_device *desc;
161 	struct usb_ctrlrequest *req;
162 	struct usb_cdc_notification *dr;
163 
164 	desc = urb->context;
165 	req = desc->irq;
166 	dr = (struct usb_cdc_notification *)desc->sbuf;
167 
168 	if (status) {
169 		switch (status) {
170 		case -ESHUTDOWN:
171 		case -ENOENT:
172 		case -ECONNRESET:
173 			return; /* unplug */
174 		case -EPIPE:
175 			set_bit(WDM_INT_STALL, &desc->flags);
176 			dev_err(&desc->intf->dev, "Stall on int endpoint\n");
177 			goto sw; /* halt is cleared in work */
178 		default:
179 			dev_err(&desc->intf->dev,
180 				"nonzero urb status received: %d\n", status);
181 			break;
182 		}
183 	}
184 
185 	if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
186 		dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
187 			urb->actual_length);
188 		goto exit;
189 	}
190 
191 	switch (dr->bNotificationType) {
192 	case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
193 		dev_dbg(&desc->intf->dev,
194 			"NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
195 			dr->wIndex, dr->wLength);
196 		break;
197 
198 	case USB_CDC_NOTIFY_NETWORK_CONNECTION:
199 
200 		dev_dbg(&desc->intf->dev,
201 			"NOTIFY_NETWORK_CONNECTION %s network",
202 			dr->wValue ? "connected to" : "disconnected from");
203 		goto exit;
204 	default:
205 		clear_bit(WDM_POLL_RUNNING, &desc->flags);
206 		dev_err(&desc->intf->dev,
207 			"unknown notification %d received: index %d len %d\n",
208 			dr->bNotificationType, dr->wIndex, dr->wLength);
209 		goto exit;
210 	}
211 
212 	req->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
213 	req->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
214 	req->wValue = 0;
215 	req->wIndex = desc->inum;
216 	req->wLength = cpu_to_le16(desc->wMaxCommand);
217 
218 	usb_fill_control_urb(
219 		desc->response,
220 		interface_to_usbdev(desc->intf),
221 		/* using common endpoint 0 */
222 		usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
223 		(unsigned char *)req,
224 		desc->inbuf,
225 		desc->wMaxCommand,
226 		wdm_in_callback,
227 		desc
228 	);
229 	desc->response->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
230 	spin_lock(&desc->iuspin);
231 	clear_bit(WDM_READ, &desc->flags);
232 	if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
233 		rv = usb_submit_urb(desc->response, GFP_ATOMIC);
234 		dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
235 			__func__, rv);
236 	}
237 	spin_unlock(&desc->iuspin);
238 	if (rv < 0) {
239 		if (rv == -EPERM)
240 			return;
241 		if (rv == -ENOMEM) {
242 sw:
243 			rv = schedule_work(&desc->rxwork);
244 			if (rv)
245 				dev_err(&desc->intf->dev,
246 					"Cannot schedule work\n");
247 		}
248 	}
249 exit:
250 	rv = usb_submit_urb(urb, GFP_ATOMIC);
251 	if (rv)
252 		dev_err(&desc->intf->dev,
253 			"%s - usb_submit_urb failed with result %d\n",
254 			__func__, rv);
255 
256 }
257 
258 static void kill_urbs(struct wdm_device *desc)
259 {
260 	/* the order here is essential */
261 	usb_kill_urb(desc->command);
262 	usb_kill_urb(desc->validity);
263 	usb_kill_urb(desc->response);
264 }
265 
266 static void free_urbs(struct wdm_device *desc)
267 {
268 	usb_free_urb(desc->validity);
269 	usb_free_urb(desc->response);
270 	usb_free_urb(desc->command);
271 }
272 
273 static void cleanup(struct wdm_device *desc)
274 {
275 	usb_buffer_free(interface_to_usbdev(desc->intf),
276 			desc->wMaxPacketSize,
277 			desc->sbuf,
278 			desc->validity->transfer_dma);
279 	usb_buffer_free(interface_to_usbdev(desc->intf),
280 			desc->wMaxCommand,
281 			desc->inbuf,
282 			desc->response->transfer_dma);
283 	kfree(desc->orq);
284 	kfree(desc->irq);
285 	kfree(desc->ubuf);
286 	free_urbs(desc);
287 	kfree(desc);
288 }
289 
290 static ssize_t wdm_write
291 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
292 {
293 	u8 *buf;
294 	int rv = -EMSGSIZE, r, we;
295 	struct wdm_device *desc = file->private_data;
296 	struct usb_ctrlrequest *req;
297 
298 	if (count > desc->wMaxCommand)
299 		count = desc->wMaxCommand;
300 
301 	spin_lock_irq(&desc->iuspin);
302 	we = desc->werr;
303 	desc->werr = 0;
304 	spin_unlock_irq(&desc->iuspin);
305 	if (we < 0)
306 		return -EIO;
307 
308 	r = mutex_lock_interruptible(&desc->wlock); /* concurrent writes */
309 	rv = -ERESTARTSYS;
310 	if (r)
311 		goto outnl;
312 
313 	r = usb_autopm_get_interface(desc->intf);
314 	if (r < 0)
315 		goto outnp;
316 
317 	if (!file->f_flags && O_NONBLOCK)
318 		r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
319 								&desc->flags));
320 	else
321 		if (test_bit(WDM_IN_USE, &desc->flags))
322 			r = -EAGAIN;
323 	if (r < 0)
324 		goto out;
325 
326 	if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
327 		rv = -ENODEV;
328 		goto out;
329 	}
330 
331 	desc->outbuf = buf = kmalloc(count, GFP_KERNEL);
332 	if (!buf) {
333 		rv = -ENOMEM;
334 		goto out;
335 	}
336 
337 	r = copy_from_user(buf, buffer, count);
338 	if (r > 0) {
339 		kfree(buf);
340 		rv = -EFAULT;
341 		goto out;
342 	}
343 
344 	req = desc->orq;
345 	usb_fill_control_urb(
346 		desc->command,
347 		interface_to_usbdev(desc->intf),
348 		/* using common endpoint 0 */
349 		usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
350 		(unsigned char *)req,
351 		buf,
352 		count,
353 		wdm_out_callback,
354 		desc
355 	);
356 
357 	req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
358 			     USB_RECIP_INTERFACE);
359 	req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
360 	req->wValue = 0;
361 	req->wIndex = desc->inum;
362 	req->wLength = cpu_to_le16(count);
363 	set_bit(WDM_IN_USE, &desc->flags);
364 
365 	rv = usb_submit_urb(desc->command, GFP_KERNEL);
366 	if (rv < 0) {
367 		kfree(buf);
368 		clear_bit(WDM_IN_USE, &desc->flags);
369 		dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
370 	} else {
371 		dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
372 			req->wIndex);
373 	}
374 out:
375 	usb_autopm_put_interface(desc->intf);
376 outnp:
377 	mutex_unlock(&desc->wlock);
378 outnl:
379 	return rv < 0 ? rv : count;
380 }
381 
382 static ssize_t wdm_read
383 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
384 {
385 	int rv, cntr = 0;
386 	int i = 0;
387 	struct wdm_device *desc = file->private_data;
388 
389 
390 	rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
391 	if (rv < 0)
392 		return -ERESTARTSYS;
393 
394 	if (desc->length == 0) {
395 		desc->read = 0;
396 retry:
397 		if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
398 			rv = -ENODEV;
399 			goto err;
400 		}
401 		i++;
402 		if (file->f_flags & O_NONBLOCK) {
403 			if (!test_bit(WDM_READ, &desc->flags)) {
404 				rv = cntr ? cntr : -EAGAIN;
405 				goto err;
406 			}
407 			rv = 0;
408 		} else {
409 			rv = wait_event_interruptible(desc->wait,
410 				test_bit(WDM_READ, &desc->flags));
411 		}
412 
413 		/* may have happened while we slept */
414 		if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
415 			rv = -ENODEV;
416 			goto err;
417 		}
418 		usb_mark_last_busy(interface_to_usbdev(desc->intf));
419 		if (rv < 0) {
420 			rv = -ERESTARTSYS;
421 			goto err;
422 		}
423 
424 		spin_lock_irq(&desc->iuspin);
425 
426 		if (desc->rerr) { /* read completed, error happened */
427 			int t = desc->rerr;
428 			desc->rerr = 0;
429 			spin_unlock_irq(&desc->iuspin);
430 			dev_err(&desc->intf->dev,
431 				"reading had resulted in %d\n", t);
432 			rv = -EIO;
433 			goto err;
434 		}
435 		/*
436 		 * recheck whether we've lost the race
437 		 * against the completion handler
438 		 */
439 		if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
440 			spin_unlock_irq(&desc->iuspin);
441 			goto retry;
442 		}
443 		if (!desc->reslength) { /* zero length read */
444 			spin_unlock_irq(&desc->iuspin);
445 			goto retry;
446 		}
447 		clear_bit(WDM_READ, &desc->flags);
448 		spin_unlock_irq(&desc->iuspin);
449 	}
450 
451 	cntr = count > desc->length ? desc->length : count;
452 	rv = copy_to_user(buffer, desc->ubuf, cntr);
453 	if (rv > 0) {
454 		rv = -EFAULT;
455 		goto err;
456 	}
457 
458 	for (i = 0; i < desc->length - cntr; i++)
459 		desc->ubuf[i] = desc->ubuf[i + cntr];
460 
461 	desc->length -= cntr;
462 	/* in case we had outstanding data */
463 	if (!desc->length)
464 		clear_bit(WDM_READ, &desc->flags);
465 	rv = cntr;
466 
467 err:
468 	mutex_unlock(&desc->rlock);
469 	if (rv < 0 && rv != -EAGAIN)
470 		dev_err(&desc->intf->dev, "wdm_read: exit error\n");
471 	return rv;
472 }
473 
474 static int wdm_flush(struct file *file, fl_owner_t id)
475 {
476 	struct wdm_device *desc = file->private_data;
477 
478 	wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
479 	if (desc->werr < 0)
480 		dev_err(&desc->intf->dev, "Error in flush path: %d\n",
481 			desc->werr);
482 
483 	return desc->werr;
484 }
485 
486 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
487 {
488 	struct wdm_device *desc = file->private_data;
489 	unsigned long flags;
490 	unsigned int mask = 0;
491 
492 	spin_lock_irqsave(&desc->iuspin, flags);
493 	if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
494 		mask = POLLERR;
495 		spin_unlock_irqrestore(&desc->iuspin, flags);
496 		goto desc_out;
497 	}
498 	if (test_bit(WDM_READ, &desc->flags))
499 		mask = POLLIN | POLLRDNORM;
500 	if (desc->rerr || desc->werr)
501 		mask |= POLLERR;
502 	if (!test_bit(WDM_IN_USE, &desc->flags))
503 		mask |= POLLOUT | POLLWRNORM;
504 	spin_unlock_irqrestore(&desc->iuspin, flags);
505 
506 	poll_wait(file, &desc->wait, wait);
507 
508 desc_out:
509 	return mask;
510 }
511 
512 static int wdm_open(struct inode *inode, struct file *file)
513 {
514 	int minor = iminor(inode);
515 	int rv = -ENODEV;
516 	struct usb_interface *intf;
517 	struct wdm_device *desc;
518 
519 	mutex_lock(&wdm_mutex);
520 	intf = usb_find_interface(&wdm_driver, minor);
521 	if (!intf)
522 		goto out;
523 
524 	desc = usb_get_intfdata(intf);
525 	if (test_bit(WDM_DISCONNECTING, &desc->flags))
526 		goto out;
527 	file->private_data = desc;
528 
529 	rv = usb_autopm_get_interface(desc->intf);
530 	if (rv < 0) {
531 		dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
532 		goto out;
533 	}
534 	intf->needs_remote_wakeup = 1;
535 
536 	mutex_lock(&desc->plock);
537 	if (!desc->count++) {
538 		rv = usb_submit_urb(desc->validity, GFP_KERNEL);
539 		if (rv < 0) {
540 			desc->count--;
541 			dev_err(&desc->intf->dev,
542 				"Error submitting int urb - %d\n", rv);
543 		}
544 	} else {
545 		rv = 0;
546 	}
547 	mutex_unlock(&desc->plock);
548 	usb_autopm_put_interface(desc->intf);
549 out:
550 	mutex_unlock(&wdm_mutex);
551 	return rv;
552 }
553 
554 static int wdm_release(struct inode *inode, struct file *file)
555 {
556 	struct wdm_device *desc = file->private_data;
557 
558 	mutex_lock(&wdm_mutex);
559 	mutex_lock(&desc->plock);
560 	desc->count--;
561 	mutex_unlock(&desc->plock);
562 
563 	if (!desc->count) {
564 		dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
565 		kill_urbs(desc);
566 		if (!test_bit(WDM_DISCONNECTING, &desc->flags))
567 			desc->intf->needs_remote_wakeup = 0;
568 	}
569 	mutex_unlock(&wdm_mutex);
570 	return 0;
571 }
572 
573 static const struct file_operations wdm_fops = {
574 	.owner =	THIS_MODULE,
575 	.read =		wdm_read,
576 	.write =	wdm_write,
577 	.open =		wdm_open,
578 	.flush =	wdm_flush,
579 	.release =	wdm_release,
580 	.poll =		wdm_poll
581 };
582 
583 static struct usb_class_driver wdm_class = {
584 	.name =		"cdc-wdm%d",
585 	.fops =		&wdm_fops,
586 	.minor_base =	WDM_MINOR_BASE,
587 };
588 
589 /* --- error handling --- */
590 static void wdm_rxwork(struct work_struct *work)
591 {
592 	struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
593 	unsigned long flags;
594 	int rv;
595 
596 	spin_lock_irqsave(&desc->iuspin, flags);
597 	if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
598 		spin_unlock_irqrestore(&desc->iuspin, flags);
599 	} else {
600 		spin_unlock_irqrestore(&desc->iuspin, flags);
601 		rv = usb_submit_urb(desc->response, GFP_KERNEL);
602 		if (rv < 0 && rv != -EPERM) {
603 			spin_lock_irqsave(&desc->iuspin, flags);
604 			if (!test_bit(WDM_DISCONNECTING, &desc->flags))
605 				schedule_work(&desc->rxwork);
606 			spin_unlock_irqrestore(&desc->iuspin, flags);
607 		}
608 	}
609 }
610 
611 /* --- hotplug --- */
612 
613 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
614 {
615 	int rv = -EINVAL;
616 	struct usb_device *udev = interface_to_usbdev(intf);
617 	struct wdm_device *desc;
618 	struct usb_host_interface *iface;
619 	struct usb_endpoint_descriptor *ep;
620 	struct usb_cdc_dmm_desc *dmhd;
621 	u8 *buffer = intf->altsetting->extra;
622 	int buflen = intf->altsetting->extralen;
623 	u16 maxcom = 0;
624 
625 	if (!buffer)
626 		goto out;
627 
628 	while (buflen > 2) {
629 		if (buffer [1] != USB_DT_CS_INTERFACE) {
630 			dev_err(&intf->dev, "skipping garbage\n");
631 			goto next_desc;
632 		}
633 
634 		switch (buffer [2]) {
635 		case USB_CDC_HEADER_TYPE:
636 			break;
637 		case USB_CDC_DMM_TYPE:
638 			dmhd = (struct usb_cdc_dmm_desc *)buffer;
639 			maxcom = le16_to_cpu(dmhd->wMaxCommand);
640 			dev_dbg(&intf->dev,
641 				"Finding maximum buffer length: %d", maxcom);
642 			break;
643 		default:
644 			dev_err(&intf->dev,
645 				"Ignoring extra header, type %d, length %d\n",
646 				buffer[2], buffer[0]);
647 			break;
648 		}
649 next_desc:
650 		buflen -= buffer[0];
651 		buffer += buffer[0];
652 	}
653 
654 	rv = -ENOMEM;
655 	desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
656 	if (!desc)
657 		goto out;
658 	mutex_init(&desc->wlock);
659 	mutex_init(&desc->rlock);
660 	mutex_init(&desc->plock);
661 	spin_lock_init(&desc->iuspin);
662 	init_waitqueue_head(&desc->wait);
663 	desc->wMaxCommand = maxcom;
664 	/* this will be expanded and needed in hardware endianness */
665 	desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
666 	desc->intf = intf;
667 	INIT_WORK(&desc->rxwork, wdm_rxwork);
668 
669 	rv = -EINVAL;
670 	iface = intf->cur_altsetting;
671 	if (iface->desc.bNumEndpoints != 1)
672 		goto err;
673 	ep = &iface->endpoint[0].desc;
674 	if (!ep || !usb_endpoint_is_int_in(ep))
675 		goto err;
676 
677 	desc->wMaxPacketSize = le16_to_cpu(ep->wMaxPacketSize);
678 	desc->bMaxPacketSize0 = udev->descriptor.bMaxPacketSize0;
679 
680 	desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
681 	if (!desc->orq)
682 		goto err;
683 	desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
684 	if (!desc->irq)
685 		goto err;
686 
687 	desc->validity = usb_alloc_urb(0, GFP_KERNEL);
688 	if (!desc->validity)
689 		goto err;
690 
691 	desc->response = usb_alloc_urb(0, GFP_KERNEL);
692 	if (!desc->response)
693 		goto err;
694 
695 	desc->command = usb_alloc_urb(0, GFP_KERNEL);
696 	if (!desc->command)
697 		goto err;
698 
699 	desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
700 	if (!desc->ubuf)
701 		goto err;
702 
703 	desc->sbuf = usb_buffer_alloc(interface_to_usbdev(intf),
704 					desc->wMaxPacketSize,
705 					GFP_KERNEL,
706 					&desc->validity->transfer_dma);
707 	if (!desc->sbuf)
708 		goto err;
709 
710 	desc->inbuf = usb_buffer_alloc(interface_to_usbdev(intf),
711 					desc->bMaxPacketSize0,
712 					GFP_KERNEL,
713 					&desc->response->transfer_dma);
714 	if (!desc->inbuf)
715 		goto err2;
716 
717 	usb_fill_int_urb(
718 		desc->validity,
719 		interface_to_usbdev(intf),
720 		usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
721 		desc->sbuf,
722 		desc->wMaxPacketSize,
723 		wdm_int_callback,
724 		desc,
725 		ep->bInterval
726 	);
727 	desc->validity->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
728 
729 	usb_set_intfdata(intf, desc);
730 	rv = usb_register_dev(intf, &wdm_class);
731 	if (rv < 0)
732 		goto err3;
733 	else
734 		dev_info(&intf->dev, "cdc-wdm%d: USB WDM device\n",
735 			intf->minor - WDM_MINOR_BASE);
736 out:
737 	return rv;
738 err3:
739 	usb_set_intfdata(intf, NULL);
740 	usb_buffer_free(interface_to_usbdev(desc->intf),
741 			desc->bMaxPacketSize0,
742 			desc->inbuf,
743 			desc->response->transfer_dma);
744 err2:
745 	usb_buffer_free(interface_to_usbdev(desc->intf),
746 			desc->wMaxPacketSize,
747 			desc->sbuf,
748 			desc->validity->transfer_dma);
749 err:
750 	free_urbs(desc);
751 	kfree(desc->ubuf);
752 	kfree(desc->orq);
753 	kfree(desc->irq);
754 	kfree(desc);
755 	return rv;
756 }
757 
758 static void wdm_disconnect(struct usb_interface *intf)
759 {
760 	struct wdm_device *desc;
761 	unsigned long flags;
762 
763 	usb_deregister_dev(intf, &wdm_class);
764 	mutex_lock(&wdm_mutex);
765 	desc = usb_get_intfdata(intf);
766 
767 	/* the spinlock makes sure no new urbs are generated in the callbacks */
768 	spin_lock_irqsave(&desc->iuspin, flags);
769 	set_bit(WDM_DISCONNECTING, &desc->flags);
770 	set_bit(WDM_READ, &desc->flags);
771 	/* to terminate pending flushes */
772 	clear_bit(WDM_IN_USE, &desc->flags);
773 	spin_unlock_irqrestore(&desc->iuspin, flags);
774 	cancel_work_sync(&desc->rxwork);
775 	kill_urbs(desc);
776 	wake_up_all(&desc->wait);
777 	if (!desc->count)
778 		cleanup(desc);
779 	mutex_unlock(&wdm_mutex);
780 }
781 
782 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
783 {
784 	struct wdm_device *desc = usb_get_intfdata(intf);
785 	int rv = 0;
786 
787 	dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
788 
789 	mutex_lock(&desc->plock);
790 #ifdef CONFIG_PM
791 	if ((message.event & PM_EVENT_AUTO) &&
792 			test_bit(WDM_IN_USE, &desc->flags)) {
793 		rv = -EBUSY;
794 	} else {
795 #endif
796 		cancel_work_sync(&desc->rxwork);
797 		kill_urbs(desc);
798 #ifdef CONFIG_PM
799 	}
800 #endif
801 	mutex_unlock(&desc->plock);
802 
803 	return rv;
804 }
805 
806 static int recover_from_urb_loss(struct wdm_device *desc)
807 {
808 	int rv = 0;
809 
810 	if (desc->count) {
811 		rv = usb_submit_urb(desc->validity, GFP_NOIO);
812 		if (rv < 0)
813 			dev_err(&desc->intf->dev,
814 				"Error resume submitting int urb - %d\n", rv);
815 	}
816 	return rv;
817 }
818 static int wdm_resume(struct usb_interface *intf)
819 {
820 	struct wdm_device *desc = usb_get_intfdata(intf);
821 	int rv;
822 
823 	dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
824 	mutex_lock(&desc->plock);
825 	rv = recover_from_urb_loss(desc);
826 	mutex_unlock(&desc->plock);
827 	return rv;
828 }
829 
830 static int wdm_pre_reset(struct usb_interface *intf)
831 {
832 	struct wdm_device *desc = usb_get_intfdata(intf);
833 
834 	mutex_lock(&desc->plock);
835 	return 0;
836 }
837 
838 static int wdm_post_reset(struct usb_interface *intf)
839 {
840 	struct wdm_device *desc = usb_get_intfdata(intf);
841 	int rv;
842 
843 	rv = recover_from_urb_loss(desc);
844 	mutex_unlock(&desc->plock);
845 	return 0;
846 }
847 
848 static struct usb_driver wdm_driver = {
849 	.name =		"cdc_wdm",
850 	.probe =	wdm_probe,
851 	.disconnect =	wdm_disconnect,
852 	.suspend =	wdm_suspend,
853 	.resume =	wdm_resume,
854 	.reset_resume =	wdm_resume,
855 	.pre_reset =	wdm_pre_reset,
856 	.post_reset =	wdm_post_reset,
857 	.id_table =	wdm_ids,
858 	.supports_autosuspend = 1,
859 };
860 
861 /* --- low level module stuff --- */
862 
863 static int __init wdm_init(void)
864 {
865 	int rv;
866 
867 	rv = usb_register(&wdm_driver);
868 
869 	return rv;
870 }
871 
872 static void __exit wdm_exit(void)
873 {
874 	usb_deregister(&wdm_driver);
875 }
876 
877 module_init(wdm_init);
878 module_exit(wdm_exit);
879 
880 MODULE_AUTHOR(DRIVER_AUTHOR);
881 MODULE_DESCRIPTION(DRIVER_DESC);
882 MODULE_LICENSE("GPL");
883