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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/*
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
34static 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
44MODULE_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
61static DEFINE_MUTEX(wdm_mutex);
62
63/* --- method tables --- */
64
65struct 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
98static struct usb_driver wdm_driver;
99
100/* --- callbacks --- */
101static 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
113static 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;
150skip_error:
151 wake_up(&desc->wait);
152
153 set_bit(WDM_READ, &desc->flags);
154 spin_unlock(&desc->iuspin);
155}
156
157static 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) {
246sw:
247 rv = schedule_work(&desc->rxwork);
248 if (rv)
249 dev_err(&desc->intf->dev,
250 "Cannot schedule work\n");
251 }
252 }
253exit:
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
262static 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
270static 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
277static 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
294static 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 }
386out:
387 usb_autopm_put_interface(desc->intf);
388outnp:
389 mutex_unlock(&desc->lock);
390outnl:
391 return rv < 0 ? rv : count;
392}
393
394static 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;
408retry:
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
476err:
477 mutex_unlock(&desc->lock);
478 return rv;
479}
480
481static 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
493static 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
515desc_out:
516 return mask;
517}
518
519static 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);
558out:
559 mutex_unlock(&wdm_mutex);
560 return rv;
561}
562
563static 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
582static 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
593static 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 --- */
600static 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
623static 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 }
659next_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);
744out:
745 return rv;
746err3:
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);
752err2:
753 usb_free_coherent(interface_to_usbdev(desc->intf),
754 desc->wMaxPacketSize,
755 desc->sbuf,
756 desc->validity->transfer_dma);
757err:
758 free_urbs(desc);
759 kfree(desc->ubuf);
760 kfree(desc->orq);
761 kfree(desc->irq);
762 kfree(desc);
763 return rv;
764}
765
766static 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
793static 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
825static 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
839static 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
853static 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
873static 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
883static 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
900static int __init wdm_init(void)
901{
902 int rv;
903
904 rv = usb_register(&wdm_driver);
905
906 return rv;
907}
908
909static void __exit wdm_exit(void)
910{
911 usb_deregister(&wdm_driver);
912}
913
914module_init(wdm_init);
915module_exit(wdm_exit);
916
917MODULE_AUTHOR(DRIVER_AUTHOR);
918MODULE_DESCRIPTION(DRIVER_DESC);
919MODULE_LICENSE("GPL");