xref: /openbmc/linux/drivers/usb/class/cdc-wdm.c (revision 54525552)
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 const 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 #define WDM_RESPONDING		7
56 #define WDM_SUSPENDING		8
57 
58 #define WDM_MAX			16
59 
60 
61 static DEFINE_MUTEX(wdm_mutex);
62 
63 /* --- method tables --- */
64 
65 struct wdm_device {
66 	u8			*inbuf; /* buffer for response */
67 	u8			*outbuf; /* buffer for command */
68 	u8			*sbuf; /* buffer for status */
69 	u8			*ubuf; /* buffer for copy to user space */
70 
71 	struct urb		*command;
72 	struct urb		*response;
73 	struct urb		*validity;
74 	struct usb_interface	*intf;
75 	struct usb_ctrlrequest	*orq;
76 	struct usb_ctrlrequest	*irq;
77 	spinlock_t		iuspin;
78 
79 	unsigned long		flags;
80 	u16			bufsize;
81 	u16			wMaxCommand;
82 	u16			wMaxPacketSize;
83 	u16			bMaxPacketSize0;
84 	__le16			inum;
85 	int			reslength;
86 	int			length;
87 	int			read;
88 	int			count;
89 	dma_addr_t		shandle;
90 	dma_addr_t		ihandle;
91 	struct mutex		lock;
92 	wait_queue_head_t	wait;
93 	struct work_struct	rxwork;
94 	int			werr;
95 	int			rerr;
96 };
97 
98 static struct usb_driver wdm_driver;
99 
100 /* --- callbacks --- */
101 static void wdm_out_callback(struct urb *urb)
102 {
103 	struct wdm_device *desc;
104 	desc = urb->context;
105 	spin_lock(&desc->iuspin);
106 	desc->werr = urb->status;
107 	spin_unlock(&desc->iuspin);
108 	clear_bit(WDM_IN_USE, &desc->flags);
109 	kfree(desc->outbuf);
110 	wake_up(&desc->wait);
111 }
112 
113 static void wdm_in_callback(struct urb *urb)
114 {
115 	struct wdm_device *desc = urb->context;
116 	int status = urb->status;
117 
118 	spin_lock(&desc->iuspin);
119 	clear_bit(WDM_RESPONDING, &desc->flags);
120 
121 	if (status) {
122 		switch (status) {
123 		case -ENOENT:
124 			dev_dbg(&desc->intf->dev,
125 				"nonzero urb status received: -ENOENT");
126 			goto skip_error;
127 		case -ECONNRESET:
128 			dev_dbg(&desc->intf->dev,
129 				"nonzero urb status received: -ECONNRESET");
130 			goto skip_error;
131 		case -ESHUTDOWN:
132 			dev_dbg(&desc->intf->dev,
133 				"nonzero urb status received: -ESHUTDOWN");
134 			goto skip_error;
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 skip_error:
151 	wake_up(&desc->wait);
152 
153 	set_bit(WDM_READ, &desc->flags);
154 	spin_unlock(&desc->iuspin);
155 }
156 
157 static void wdm_int_callback(struct urb *urb)
158 {
159 	int rv = 0;
160 	int status = urb->status;
161 	struct wdm_device *desc;
162 	struct usb_ctrlrequest *req;
163 	struct usb_cdc_notification *dr;
164 
165 	desc = urb->context;
166 	req = desc->irq;
167 	dr = (struct usb_cdc_notification *)desc->sbuf;
168 
169 	if (status) {
170 		switch (status) {
171 		case -ESHUTDOWN:
172 		case -ENOENT:
173 		case -ECONNRESET:
174 			return; /* unplug */
175 		case -EPIPE:
176 			set_bit(WDM_INT_STALL, &desc->flags);
177 			dev_err(&desc->intf->dev, "Stall on int endpoint\n");
178 			goto sw; /* halt is cleared in work */
179 		default:
180 			dev_err(&desc->intf->dev,
181 				"nonzero urb status received: %d\n", status);
182 			break;
183 		}
184 	}
185 
186 	if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
187 		dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
188 			urb->actual_length);
189 		goto exit;
190 	}
191 
192 	switch (dr->bNotificationType) {
193 	case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
194 		dev_dbg(&desc->intf->dev,
195 			"NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
196 			dr->wIndex, dr->wLength);
197 		break;
198 
199 	case USB_CDC_NOTIFY_NETWORK_CONNECTION:
200 
201 		dev_dbg(&desc->intf->dev,
202 			"NOTIFY_NETWORK_CONNECTION %s network",
203 			dr->wValue ? "connected to" : "disconnected from");
204 		goto exit;
205 	default:
206 		clear_bit(WDM_POLL_RUNNING, &desc->flags);
207 		dev_err(&desc->intf->dev,
208 			"unknown notification %d received: index %d len %d\n",
209 			dr->bNotificationType, dr->wIndex, dr->wLength);
210 		goto exit;
211 	}
212 
213 	req->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
214 	req->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
215 	req->wValue = 0;
216 	req->wIndex = desc->inum;
217 	req->wLength = cpu_to_le16(desc->wMaxCommand);
218 
219 	usb_fill_control_urb(
220 		desc->response,
221 		interface_to_usbdev(desc->intf),
222 		/* using common endpoint 0 */
223 		usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
224 		(unsigned char *)req,
225 		desc->inbuf,
226 		desc->wMaxCommand,
227 		wdm_in_callback,
228 		desc
229 	);
230 	desc->response->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
231 	spin_lock(&desc->iuspin);
232 	clear_bit(WDM_READ, &desc->flags);
233 	set_bit(WDM_RESPONDING, &desc->flags);
234 	if (!test_bit(WDM_DISCONNECTING, &desc->flags)
235 		&& !test_bit(WDM_SUSPENDING, &desc->flags)) {
236 		rv = usb_submit_urb(desc->response, GFP_ATOMIC);
237 		dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
238 			__func__, rv);
239 	}
240 	spin_unlock(&desc->iuspin);
241 	if (rv < 0) {
242 		clear_bit(WDM_RESPONDING, &desc->flags);
243 		if (rv == -EPERM)
244 			return;
245 		if (rv == -ENOMEM) {
246 sw:
247 			rv = schedule_work(&desc->rxwork);
248 			if (rv)
249 				dev_err(&desc->intf->dev,
250 					"Cannot schedule work\n");
251 		}
252 	}
253 exit:
254 	rv = usb_submit_urb(urb, GFP_ATOMIC);
255 	if (rv)
256 		dev_err(&desc->intf->dev,
257 			"%s - usb_submit_urb failed with result %d\n",
258 			__func__, rv);
259 
260 }
261 
262 static void kill_urbs(struct wdm_device *desc)
263 {
264 	/* the order here is essential */
265 	usb_kill_urb(desc->command);
266 	usb_kill_urb(desc->validity);
267 	usb_kill_urb(desc->response);
268 }
269 
270 static void free_urbs(struct wdm_device *desc)
271 {
272 	usb_free_urb(desc->validity);
273 	usb_free_urb(desc->response);
274 	usb_free_urb(desc->command);
275 }
276 
277 static void cleanup(struct wdm_device *desc)
278 {
279 	usb_free_coherent(interface_to_usbdev(desc->intf),
280 			  desc->wMaxPacketSize,
281 			  desc->sbuf,
282 			  desc->validity->transfer_dma);
283 	usb_free_coherent(interface_to_usbdev(desc->intf),
284 			  desc->bMaxPacketSize0,
285 			  desc->inbuf,
286 			  desc->response->transfer_dma);
287 	kfree(desc->orq);
288 	kfree(desc->irq);
289 	kfree(desc->ubuf);
290 	free_urbs(desc);
291 	kfree(desc);
292 }
293 
294 static ssize_t wdm_write
295 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
296 {
297 	u8 *buf;
298 	int rv = -EMSGSIZE, r, we;
299 	struct wdm_device *desc = file->private_data;
300 	struct usb_ctrlrequest *req;
301 
302 	if (count > desc->wMaxCommand)
303 		count = desc->wMaxCommand;
304 
305 	spin_lock_irq(&desc->iuspin);
306 	we = desc->werr;
307 	desc->werr = 0;
308 	spin_unlock_irq(&desc->iuspin);
309 	if (we < 0)
310 		return -EIO;
311 
312 	desc->outbuf = buf = kmalloc(count, GFP_KERNEL);
313 	if (!buf) {
314 		rv = -ENOMEM;
315 		goto outnl;
316 	}
317 
318 	r = copy_from_user(buf, buffer, count);
319 	if (r > 0) {
320 		kfree(buf);
321 		rv = -EFAULT;
322 		goto outnl;
323 	}
324 
325 	/* concurrent writes and disconnect */
326 	r = mutex_lock_interruptible(&desc->lock);
327 	rv = -ERESTARTSYS;
328 	if (r) {
329 		kfree(buf);
330 		goto outnl;
331 	}
332 
333 	if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
334 		kfree(buf);
335 		rv = -ENODEV;
336 		goto outnp;
337 	}
338 
339 	r = usb_autopm_get_interface(desc->intf);
340 	if (r < 0) {
341 		kfree(buf);
342 		goto outnp;
343 	}
344 
345 	if (!(file->f_flags & O_NONBLOCK))
346 		r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
347 								&desc->flags));
348 	else
349 		if (test_bit(WDM_IN_USE, &desc->flags))
350 			r = -EAGAIN;
351 	if (r < 0) {
352 		kfree(buf);
353 		goto out;
354 	}
355 
356 	req = desc->orq;
357 	usb_fill_control_urb(
358 		desc->command,
359 		interface_to_usbdev(desc->intf),
360 		/* using common endpoint 0 */
361 		usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
362 		(unsigned char *)req,
363 		buf,
364 		count,
365 		wdm_out_callback,
366 		desc
367 	);
368 
369 	req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
370 			     USB_RECIP_INTERFACE);
371 	req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
372 	req->wValue = 0;
373 	req->wIndex = desc->inum;
374 	req->wLength = cpu_to_le16(count);
375 	set_bit(WDM_IN_USE, &desc->flags);
376 
377 	rv = usb_submit_urb(desc->command, GFP_KERNEL);
378 	if (rv < 0) {
379 		kfree(buf);
380 		clear_bit(WDM_IN_USE, &desc->flags);
381 		dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
382 	} else {
383 		dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
384 			req->wIndex);
385 	}
386 out:
387 	usb_autopm_put_interface(desc->intf);
388 outnp:
389 	mutex_unlock(&desc->lock);
390 outnl:
391 	return rv < 0 ? rv : count;
392 }
393 
394 static ssize_t wdm_read
395 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
396 {
397 	int rv, cntr = 0;
398 	int i = 0;
399 	struct wdm_device *desc = file->private_data;
400 
401 
402 	rv = mutex_lock_interruptible(&desc->lock); /*concurrent reads */
403 	if (rv < 0)
404 		return -ERESTARTSYS;
405 
406 	if (desc->length == 0) {
407 		desc->read = 0;
408 retry:
409 		if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
410 			rv = -ENODEV;
411 			goto err;
412 		}
413 		i++;
414 		if (file->f_flags & O_NONBLOCK) {
415 			if (!test_bit(WDM_READ, &desc->flags)) {
416 				rv = cntr ? cntr : -EAGAIN;
417 				goto err;
418 			}
419 			rv = 0;
420 		} else {
421 			rv = wait_event_interruptible(desc->wait,
422 				test_bit(WDM_READ, &desc->flags));
423 		}
424 
425 		/* may have happened while we slept */
426 		if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
427 			rv = -ENODEV;
428 			goto err;
429 		}
430 		usb_mark_last_busy(interface_to_usbdev(desc->intf));
431 		if (rv < 0) {
432 			rv = -ERESTARTSYS;
433 			goto err;
434 		}
435 
436 		spin_lock_irq(&desc->iuspin);
437 
438 		if (desc->rerr) { /* read completed, error happened */
439 			desc->rerr = 0;
440 			spin_unlock_irq(&desc->iuspin);
441 			rv = -EIO;
442 			goto err;
443 		}
444 		/*
445 		 * recheck whether we've lost the race
446 		 * against the completion handler
447 		 */
448 		if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
449 			spin_unlock_irq(&desc->iuspin);
450 			goto retry;
451 		}
452 		if (!desc->reslength) { /* zero length read */
453 			spin_unlock_irq(&desc->iuspin);
454 			goto retry;
455 		}
456 		clear_bit(WDM_READ, &desc->flags);
457 		spin_unlock_irq(&desc->iuspin);
458 	}
459 
460 	cntr = count > desc->length ? desc->length : count;
461 	rv = copy_to_user(buffer, desc->ubuf, cntr);
462 	if (rv > 0) {
463 		rv = -EFAULT;
464 		goto err;
465 	}
466 
467 	for (i = 0; i < desc->length - cntr; i++)
468 		desc->ubuf[i] = desc->ubuf[i + cntr];
469 
470 	desc->length -= cntr;
471 	/* in case we had outstanding data */
472 	if (!desc->length)
473 		clear_bit(WDM_READ, &desc->flags);
474 	rv = cntr;
475 
476 err:
477 	mutex_unlock(&desc->lock);
478 	return rv;
479 }
480 
481 static int wdm_flush(struct file *file, fl_owner_t id)
482 {
483 	struct wdm_device *desc = file->private_data;
484 
485 	wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
486 	if (desc->werr < 0)
487 		dev_err(&desc->intf->dev, "Error in flush path: %d\n",
488 			desc->werr);
489 
490 	return desc->werr;
491 }
492 
493 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
494 {
495 	struct wdm_device *desc = file->private_data;
496 	unsigned long flags;
497 	unsigned int mask = 0;
498 
499 	spin_lock_irqsave(&desc->iuspin, flags);
500 	if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
501 		mask = POLLERR;
502 		spin_unlock_irqrestore(&desc->iuspin, flags);
503 		goto desc_out;
504 	}
505 	if (test_bit(WDM_READ, &desc->flags))
506 		mask = POLLIN | POLLRDNORM;
507 	if (desc->rerr || desc->werr)
508 		mask |= POLLERR;
509 	if (!test_bit(WDM_IN_USE, &desc->flags))
510 		mask |= POLLOUT | POLLWRNORM;
511 	spin_unlock_irqrestore(&desc->iuspin, flags);
512 
513 	poll_wait(file, &desc->wait, wait);
514 
515 desc_out:
516 	return mask;
517 }
518 
519 static int wdm_open(struct inode *inode, struct file *file)
520 {
521 	int minor = iminor(inode);
522 	int rv = -ENODEV;
523 	struct usb_interface *intf;
524 	struct wdm_device *desc;
525 
526 	mutex_lock(&wdm_mutex);
527 	intf = usb_find_interface(&wdm_driver, minor);
528 	if (!intf)
529 		goto out;
530 
531 	desc = usb_get_intfdata(intf);
532 	if (test_bit(WDM_DISCONNECTING, &desc->flags))
533 		goto out;
534 	file->private_data = desc;
535 
536 	rv = usb_autopm_get_interface(desc->intf);
537 	if (rv < 0) {
538 		dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
539 		goto out;
540 	}
541 	intf->needs_remote_wakeup = 1;
542 
543 	mutex_lock(&desc->lock);
544 	if (!desc->count++) {
545 		desc->werr = 0;
546 		desc->rerr = 0;
547 		rv = usb_submit_urb(desc->validity, GFP_KERNEL);
548 		if (rv < 0) {
549 			desc->count--;
550 			dev_err(&desc->intf->dev,
551 				"Error submitting int urb - %d\n", rv);
552 		}
553 	} else {
554 		rv = 0;
555 	}
556 	mutex_unlock(&desc->lock);
557 	usb_autopm_put_interface(desc->intf);
558 out:
559 	mutex_unlock(&wdm_mutex);
560 	return rv;
561 }
562 
563 static int wdm_release(struct inode *inode, struct file *file)
564 {
565 	struct wdm_device *desc = file->private_data;
566 
567 	mutex_lock(&wdm_mutex);
568 	mutex_lock(&desc->lock);
569 	desc->count--;
570 	mutex_unlock(&desc->lock);
571 
572 	if (!desc->count) {
573 		dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
574 		kill_urbs(desc);
575 		if (!test_bit(WDM_DISCONNECTING, &desc->flags))
576 			desc->intf->needs_remote_wakeup = 0;
577 	}
578 	mutex_unlock(&wdm_mutex);
579 	return 0;
580 }
581 
582 static const struct file_operations wdm_fops = {
583 	.owner =	THIS_MODULE,
584 	.read =		wdm_read,
585 	.write =	wdm_write,
586 	.open =		wdm_open,
587 	.flush =	wdm_flush,
588 	.release =	wdm_release,
589 	.poll =		wdm_poll,
590 	.llseek =	noop_llseek,
591 };
592 
593 static struct usb_class_driver wdm_class = {
594 	.name =		"cdc-wdm%d",
595 	.fops =		&wdm_fops,
596 	.minor_base =	WDM_MINOR_BASE,
597 };
598 
599 /* --- error handling --- */
600 static void wdm_rxwork(struct work_struct *work)
601 {
602 	struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
603 	unsigned long flags;
604 	int rv;
605 
606 	spin_lock_irqsave(&desc->iuspin, flags);
607 	if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
608 		spin_unlock_irqrestore(&desc->iuspin, flags);
609 	} else {
610 		spin_unlock_irqrestore(&desc->iuspin, flags);
611 		rv = usb_submit_urb(desc->response, GFP_KERNEL);
612 		if (rv < 0 && rv != -EPERM) {
613 			spin_lock_irqsave(&desc->iuspin, flags);
614 			if (!test_bit(WDM_DISCONNECTING, &desc->flags))
615 				schedule_work(&desc->rxwork);
616 			spin_unlock_irqrestore(&desc->iuspin, flags);
617 		}
618 	}
619 }
620 
621 /* --- hotplug --- */
622 
623 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
624 {
625 	int rv = -EINVAL;
626 	struct usb_device *udev = interface_to_usbdev(intf);
627 	struct wdm_device *desc;
628 	struct usb_host_interface *iface;
629 	struct usb_endpoint_descriptor *ep;
630 	struct usb_cdc_dmm_desc *dmhd;
631 	u8 *buffer = intf->altsetting->extra;
632 	int buflen = intf->altsetting->extralen;
633 	u16 maxcom = 0;
634 
635 	if (!buffer)
636 		goto out;
637 
638 	while (buflen > 2) {
639 		if (buffer [1] != USB_DT_CS_INTERFACE) {
640 			dev_err(&intf->dev, "skipping garbage\n");
641 			goto next_desc;
642 		}
643 
644 		switch (buffer [2]) {
645 		case USB_CDC_HEADER_TYPE:
646 			break;
647 		case USB_CDC_DMM_TYPE:
648 			dmhd = (struct usb_cdc_dmm_desc *)buffer;
649 			maxcom = le16_to_cpu(dmhd->wMaxCommand);
650 			dev_dbg(&intf->dev,
651 				"Finding maximum buffer length: %d", maxcom);
652 			break;
653 		default:
654 			dev_err(&intf->dev,
655 				"Ignoring extra header, type %d, length %d\n",
656 				buffer[2], buffer[0]);
657 			break;
658 		}
659 next_desc:
660 		buflen -= buffer[0];
661 		buffer += buffer[0];
662 	}
663 
664 	rv = -ENOMEM;
665 	desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
666 	if (!desc)
667 		goto out;
668 	mutex_init(&desc->lock);
669 	spin_lock_init(&desc->iuspin);
670 	init_waitqueue_head(&desc->wait);
671 	desc->wMaxCommand = maxcom;
672 	/* this will be expanded and needed in hardware endianness */
673 	desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
674 	desc->intf = intf;
675 	INIT_WORK(&desc->rxwork, wdm_rxwork);
676 
677 	rv = -EINVAL;
678 	iface = intf->cur_altsetting;
679 	if (iface->desc.bNumEndpoints != 1)
680 		goto err;
681 	ep = &iface->endpoint[0].desc;
682 	if (!ep || !usb_endpoint_is_int_in(ep))
683 		goto err;
684 
685 	desc->wMaxPacketSize = le16_to_cpu(ep->wMaxPacketSize);
686 	desc->bMaxPacketSize0 = udev->descriptor.bMaxPacketSize0;
687 
688 	desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
689 	if (!desc->orq)
690 		goto err;
691 	desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
692 	if (!desc->irq)
693 		goto err;
694 
695 	desc->validity = usb_alloc_urb(0, GFP_KERNEL);
696 	if (!desc->validity)
697 		goto err;
698 
699 	desc->response = usb_alloc_urb(0, GFP_KERNEL);
700 	if (!desc->response)
701 		goto err;
702 
703 	desc->command = usb_alloc_urb(0, GFP_KERNEL);
704 	if (!desc->command)
705 		goto err;
706 
707 	desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
708 	if (!desc->ubuf)
709 		goto err;
710 
711 	desc->sbuf = usb_alloc_coherent(interface_to_usbdev(intf),
712 					desc->wMaxPacketSize,
713 					GFP_KERNEL,
714 					&desc->validity->transfer_dma);
715 	if (!desc->sbuf)
716 		goto err;
717 
718 	desc->inbuf = usb_alloc_coherent(interface_to_usbdev(intf),
719 					 desc->bMaxPacketSize0,
720 					 GFP_KERNEL,
721 					 &desc->response->transfer_dma);
722 	if (!desc->inbuf)
723 		goto err2;
724 
725 	usb_fill_int_urb(
726 		desc->validity,
727 		interface_to_usbdev(intf),
728 		usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
729 		desc->sbuf,
730 		desc->wMaxPacketSize,
731 		wdm_int_callback,
732 		desc,
733 		ep->bInterval
734 	);
735 	desc->validity->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
736 
737 	usb_set_intfdata(intf, desc);
738 	rv = usb_register_dev(intf, &wdm_class);
739 	if (rv < 0)
740 		goto err3;
741 	else
742 		dev_info(&intf->dev, "cdc-wdm%d: USB WDM device\n",
743 			intf->minor - WDM_MINOR_BASE);
744 out:
745 	return rv;
746 err3:
747 	usb_set_intfdata(intf, NULL);
748 	usb_free_coherent(interface_to_usbdev(desc->intf),
749 			  desc->bMaxPacketSize0,
750 			desc->inbuf,
751 			desc->response->transfer_dma);
752 err2:
753 	usb_free_coherent(interface_to_usbdev(desc->intf),
754 			  desc->wMaxPacketSize,
755 			  desc->sbuf,
756 			  desc->validity->transfer_dma);
757 err:
758 	free_urbs(desc);
759 	kfree(desc->ubuf);
760 	kfree(desc->orq);
761 	kfree(desc->irq);
762 	kfree(desc);
763 	return rv;
764 }
765 
766 static void wdm_disconnect(struct usb_interface *intf)
767 {
768 	struct wdm_device *desc;
769 	unsigned long flags;
770 
771 	usb_deregister_dev(intf, &wdm_class);
772 	mutex_lock(&wdm_mutex);
773 	desc = usb_get_intfdata(intf);
774 
775 	/* the spinlock makes sure no new urbs are generated in the callbacks */
776 	spin_lock_irqsave(&desc->iuspin, flags);
777 	set_bit(WDM_DISCONNECTING, &desc->flags);
778 	set_bit(WDM_READ, &desc->flags);
779 	/* to terminate pending flushes */
780 	clear_bit(WDM_IN_USE, &desc->flags);
781 	spin_unlock_irqrestore(&desc->iuspin, flags);
782 	mutex_lock(&desc->lock);
783 	kill_urbs(desc);
784 	cancel_work_sync(&desc->rxwork);
785 	mutex_unlock(&desc->lock);
786 	wake_up_all(&desc->wait);
787 	if (!desc->count)
788 		cleanup(desc);
789 	mutex_unlock(&wdm_mutex);
790 }
791 
792 #ifdef CONFIG_PM
793 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
794 {
795 	struct wdm_device *desc = usb_get_intfdata(intf);
796 	int rv = 0;
797 
798 	dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
799 
800 	/* if this is an autosuspend the caller does the locking */
801 	if (!(message.event & PM_EVENT_AUTO))
802 		mutex_lock(&desc->lock);
803 	spin_lock_irq(&desc->iuspin);
804 
805 	if ((message.event & PM_EVENT_AUTO) &&
806 			(test_bit(WDM_IN_USE, &desc->flags)
807 			|| test_bit(WDM_RESPONDING, &desc->flags))) {
808 		spin_unlock_irq(&desc->iuspin);
809 		rv = -EBUSY;
810 	} else {
811 
812 		set_bit(WDM_SUSPENDING, &desc->flags);
813 		spin_unlock_irq(&desc->iuspin);
814 		/* callback submits work - order is essential */
815 		kill_urbs(desc);
816 		cancel_work_sync(&desc->rxwork);
817 	}
818 	if (!(message.event & PM_EVENT_AUTO))
819 		mutex_unlock(&desc->lock);
820 
821 	return rv;
822 }
823 #endif
824 
825 static int recover_from_urb_loss(struct wdm_device *desc)
826 {
827 	int rv = 0;
828 
829 	if (desc->count) {
830 		rv = usb_submit_urb(desc->validity, GFP_NOIO);
831 		if (rv < 0)
832 			dev_err(&desc->intf->dev,
833 				"Error resume submitting int urb - %d\n", rv);
834 	}
835 	return rv;
836 }
837 
838 #ifdef CONFIG_PM
839 static int wdm_resume(struct usb_interface *intf)
840 {
841 	struct wdm_device *desc = usb_get_intfdata(intf);
842 	int rv;
843 
844 	dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
845 
846 	clear_bit(WDM_SUSPENDING, &desc->flags);
847 	rv = recover_from_urb_loss(desc);
848 
849 	return rv;
850 }
851 #endif
852 
853 static int wdm_pre_reset(struct usb_interface *intf)
854 {
855 	struct wdm_device *desc = usb_get_intfdata(intf);
856 
857 	mutex_lock(&desc->lock);
858 	kill_urbs(desc);
859 
860 	/*
861 	 * we notify everybody using poll of
862 	 * an exceptional situation
863 	 * must be done before recovery lest a spontaneous
864 	 * message from the device is lost
865 	 */
866 	spin_lock_irq(&desc->iuspin);
867 	desc->rerr = -EINTR;
868 	spin_unlock_irq(&desc->iuspin);
869 	wake_up_all(&desc->wait);
870 	return 0;
871 }
872 
873 static int wdm_post_reset(struct usb_interface *intf)
874 {
875 	struct wdm_device *desc = usb_get_intfdata(intf);
876 	int rv;
877 
878 	rv = recover_from_urb_loss(desc);
879 	mutex_unlock(&desc->lock);
880 	return 0;
881 }
882 
883 static struct usb_driver wdm_driver = {
884 	.name =		"cdc_wdm",
885 	.probe =	wdm_probe,
886 	.disconnect =	wdm_disconnect,
887 #ifdef CONFIG_PM
888 	.suspend =	wdm_suspend,
889 	.resume =	wdm_resume,
890 	.reset_resume =	wdm_resume,
891 #endif
892 	.pre_reset =	wdm_pre_reset,
893 	.post_reset =	wdm_post_reset,
894 	.id_table =	wdm_ids,
895 	.supports_autosuspend = 1,
896 };
897 
898 /* --- low level module stuff --- */
899 
900 static int __init wdm_init(void)
901 {
902 	int rv;
903 
904 	rv = usb_register(&wdm_driver);
905 
906 	return rv;
907 }
908 
909 static void __exit wdm_exit(void)
910 {
911 	usb_deregister(&wdm_driver);
912 }
913 
914 module_init(wdm_init);
915 module_exit(wdm_exit);
916 
917 MODULE_AUTHOR(DRIVER_AUTHOR);
918 MODULE_DESCRIPTION(DRIVER_DESC);
919 MODULE_LICENSE("GPL");
920