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Merge tag 'trace-v5.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...
[linux/fpc-iii.git] / drivers / usb / class / cdc-wdm.c
blob508b1c3f8b731bae17acb90b39a9ab64f683adb0
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
33 static 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
43 MODULE_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 /* we cannot wait forever at flush() */
62 #define WDM_FLUSH_TIMEOUT (30 * HZ)
63
64 /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
65 #define WDM_DEFAULT_BUFSIZE 256
66
67 static DEFINE_MUTEX(wdm_mutex);
68 static DEFINE_SPINLOCK(wdm_device_list_lock);
69 static LIST_HEAD(wdm_device_list);
70
71 /* --- method tables --- */
72
73 struct wdm_device {
74 u8 *inbuf; /* buffer for response */
75 u8 *outbuf; /* buffer for command */
76 u8 *sbuf; /* buffer for status */
77 u8 *ubuf; /* buffer for copy to user space */
78
79 struct urb *command;
80 struct urb *response;
81 struct urb *validity;
82 struct usb_interface *intf;
83 struct usb_ctrlrequest *orq;
84 struct usb_ctrlrequest *irq;
85 spinlock_t iuspin;
86
87 unsigned long flags;
88 u16 bufsize;
89 u16 wMaxCommand;
90 u16 wMaxPacketSize;
91 __le16 inum;
92 int reslength;
93 int length;
94 int read;
95 int count;
96 dma_addr_t shandle;
97 dma_addr_t ihandle;
98 struct mutex wlock;
99 struct mutex rlock;
100 wait_queue_head_t wait;
101 struct work_struct rxwork;
102 struct work_struct service_outs_intr;
103 int werr;
104 int rerr;
105 int resp_count;
106
107 struct list_head device_list;
108 int (*manage_power)(struct usb_interface *, int);
109 };
110
111 static struct usb_driver wdm_driver;
112
113 /* return intfdata if we own the interface, else look up intf in the list */
114 static struct wdm_device *wdm_find_device(struct usb_interface *intf)
115 {
116 struct wdm_device *desc;
117
118 spin_lock(&wdm_device_list_lock);
119 list_for_each_entry(desc, &wdm_device_list, device_list)
120 if (desc->intf == intf)
121 goto found;
122 desc = NULL;
123 found:
124 spin_unlock(&wdm_device_list_lock);
125
126 return desc;
127 }
128
129 static struct wdm_device *wdm_find_device_by_minor(int minor)
130 {
131 struct wdm_device *desc;
132
133 spin_lock(&wdm_device_list_lock);
134 list_for_each_entry(desc, &wdm_device_list, device_list)
135 if (desc->intf->minor == minor)
136 goto found;
137 desc = NULL;
138 found:
139 spin_unlock(&wdm_device_list_lock);
140
141 return desc;
142 }
143
144 /* --- callbacks --- */
145 static void wdm_out_callback(struct urb *urb)
146 {
147 struct wdm_device *desc;
148 unsigned long flags;
149
150 desc = urb->context;
151 spin_lock_irqsave(&desc->iuspin, flags);
152 desc->werr = urb->status;
153 spin_unlock_irqrestore(&desc->iuspin, flags);
154 kfree(desc->outbuf);
155 desc->outbuf = NULL;
156 clear_bit(WDM_IN_USE, &desc->flags);
157 wake_up_all(&desc->wait);
158 }
159
160 static void wdm_in_callback(struct urb *urb)
161 {
162 unsigned long flags;
163 struct wdm_device *desc = urb->context;
164 int status = urb->status;
165 int length = urb->actual_length;
166
167 spin_lock_irqsave(&desc->iuspin, flags);
168 clear_bit(WDM_RESPONDING, &desc->flags);
169
170 if (status) {
171 switch (status) {
172 case -ENOENT:
173 dev_dbg(&desc->intf->dev,
174 "nonzero urb status received: -ENOENT\n");
175 goto skip_error;
176 case -ECONNRESET:
177 dev_dbg(&desc->intf->dev,
178 "nonzero urb status received: -ECONNRESET\n");
179 goto skip_error;
180 case -ESHUTDOWN:
181 dev_dbg(&desc->intf->dev,
182 "nonzero urb status received: -ESHUTDOWN\n");
183 goto skip_error;
184 case -EPIPE:
185 dev_err(&desc->intf->dev,
186 "nonzero urb status received: -EPIPE\n");
187 break;
188 default:
189 dev_err(&desc->intf->dev,
190 "Unexpected error %d\n", status);
191 break;
192 }
193 }
194
195 /*
196 * only set a new error if there is no previous error.
197 * Errors are only cleared during read/open
198 * Avoid propagating -EPIPE (stall) to userspace since it is
199 * better handled as an empty read
200 */
201 if (desc->rerr == 0 && status != -EPIPE)
202 desc->rerr = status;
203
204 if (length + desc->length > desc->wMaxCommand) {
205 /* The buffer would overflow */
206 set_bit(WDM_OVERFLOW, &desc->flags);
207 } else {
208 /* we may already be in overflow */
209 if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
210 memmove(desc->ubuf + desc->length, desc->inbuf, length);
211 desc->length += length;
212 desc->reslength = length;
213 }
214 }
215 skip_error:
216
217 if (desc->rerr) {
218 /*
219 * Since there was an error, userspace may decide to not read
220 * any data after poll'ing.
221 * We should respond to further attempts from the device to send
222 * data, so that we can get unstuck.
223 */
224 schedule_work(&desc->service_outs_intr);
225 } else {
226 set_bit(WDM_READ, &desc->flags);
227 wake_up(&desc->wait);
228 }
229 spin_unlock_irqrestore(&desc->iuspin, flags);
230 }
231
232 static void wdm_int_callback(struct urb *urb)
233 {
234 unsigned long flags;
235 int rv = 0;
236 int responding;
237 int status = urb->status;
238 struct wdm_device *desc;
239 struct usb_cdc_notification *dr;
240
241 desc = urb->context;
242 dr = (struct usb_cdc_notification *)desc->sbuf;
243
244 if (status) {
245 switch (status) {
246 case -ESHUTDOWN:
247 case -ENOENT:
248 case -ECONNRESET:
249 return; /* unplug */
250 case -EPIPE:
251 set_bit(WDM_INT_STALL, &desc->flags);
252 dev_err(&desc->intf->dev, "Stall on int endpoint\n");
253 goto sw; /* halt is cleared in work */
254 default:
255 dev_err(&desc->intf->dev,
256 "nonzero urb status received: %d\n", status);
257 break;
258 }
259 }
260
261 if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
262 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
263 urb->actual_length);
264 goto exit;
265 }
266
267 switch (dr->bNotificationType) {
268 case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
269 dev_dbg(&desc->intf->dev,
270 "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d\n",
271 le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength));
272 break;
273
274 case USB_CDC_NOTIFY_NETWORK_CONNECTION:
275
276 dev_dbg(&desc->intf->dev,
277 "NOTIFY_NETWORK_CONNECTION %s network\n",
278 dr->wValue ? "connected to" : "disconnected from");
279 goto exit;
280 case USB_CDC_NOTIFY_SPEED_CHANGE:
281 dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)\n",
282 urb->actual_length);
283 goto exit;
284 default:
285 clear_bit(WDM_POLL_RUNNING, &desc->flags);
286 dev_err(&desc->intf->dev,
287 "unknown notification %d received: index %d len %d\n",
288 dr->bNotificationType,
289 le16_to_cpu(dr->wIndex),
290 le16_to_cpu(dr->wLength));
291 goto exit;
292 }
293
294 spin_lock_irqsave(&desc->iuspin, flags);
295 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
296 if (!desc->resp_count++ && !responding
297 && !test_bit(WDM_DISCONNECTING, &desc->flags)
298 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
299 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
300 dev_dbg(&desc->intf->dev, "submit response URB %d\n", rv);
301 }
302 spin_unlock_irqrestore(&desc->iuspin, flags);
303 if (rv < 0) {
304 clear_bit(WDM_RESPONDING, &desc->flags);
305 if (rv == -EPERM)
306 return;
307 if (rv == -ENOMEM) {
308 sw:
309 rv = schedule_work(&desc->rxwork);
310 if (rv)
311 dev_err(&desc->intf->dev,
312 "Cannot schedule work\n");
313 }
314 }
315 exit:
316 rv = usb_submit_urb(urb, GFP_ATOMIC);
317 if (rv)
318 dev_err(&desc->intf->dev,
319 "%s - usb_submit_urb failed with result %d\n",
320 __func__, rv);
321
322 }
323
324 static void kill_urbs(struct wdm_device *desc)
325 {
326 /* the order here is essential */
327 usb_kill_urb(desc->command);
328 usb_kill_urb(desc->validity);
329 usb_kill_urb(desc->response);
330 }
331
332 static void free_urbs(struct wdm_device *desc)
333 {
334 usb_free_urb(desc->validity);
335 usb_free_urb(desc->response);
336 usb_free_urb(desc->command);
337 }
338
339 static void cleanup(struct wdm_device *desc)
340 {
341 kfree(desc->sbuf);
342 kfree(desc->inbuf);
343 kfree(desc->orq);
344 kfree(desc->irq);
345 kfree(desc->ubuf);
346 free_urbs(desc);
347 kfree(desc);
348 }
349
350 static ssize_t wdm_write
351 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
352 {
353 u8 *buf;
354 int rv = -EMSGSIZE, r, we;
355 struct wdm_device *desc = file->private_data;
356 struct usb_ctrlrequest *req;
357
358 if (count > desc->wMaxCommand)
359 count = desc->wMaxCommand;
360
361 spin_lock_irq(&desc->iuspin);
362 we = desc->werr;
363 desc->werr = 0;
364 spin_unlock_irq(&desc->iuspin);
365 if (we < 0)
366 return usb_translate_errors(we);
367
368 buf = memdup_user(buffer, count);
369 if (IS_ERR(buf))
370 return PTR_ERR(buf);
371
372 /* concurrent writes and disconnect */
373 r = mutex_lock_interruptible(&desc->wlock);
374 rv = -ERESTARTSYS;
375 if (r)
376 goto out_free_mem;
377
378 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
379 rv = -ENODEV;
380 goto out_free_mem_lock;
381 }
382
383 r = usb_autopm_get_interface(desc->intf);
384 if (r < 0) {
385 rv = usb_translate_errors(r);
386 goto out_free_mem_lock;
387 }
388
389 if (!(file->f_flags & O_NONBLOCK))
390 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
391 &desc->flags));
392 else
393 if (test_bit(WDM_IN_USE, &desc->flags))
394 r = -EAGAIN;
395
396 if (test_bit(WDM_RESETTING, &desc->flags))
397 r = -EIO;
398
399 if (test_bit(WDM_DISCONNECTING, &desc->flags))
400 r = -ENODEV;
401
402 if (r < 0) {
403 rv = r;
404 goto out_free_mem_pm;
405 }
406
407 req = desc->orq;
408 usb_fill_control_urb(
409 desc->command,
410 interface_to_usbdev(desc->intf),
411 /* using common endpoint 0 */
412 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
413 (unsigned char *)req,
414 buf,
415 count,
416 wdm_out_callback,
417 desc
418 );
419
420 req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
421 USB_RECIP_INTERFACE);
422 req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
423 req->wValue = 0;
424 req->wIndex = desc->inum; /* already converted */
425 req->wLength = cpu_to_le16(count);
426 set_bit(WDM_IN_USE, &desc->flags);
427 desc->outbuf = buf;
428
429 rv = usb_submit_urb(desc->command, GFP_KERNEL);
430 if (rv < 0) {
431 desc->outbuf = NULL;
432 clear_bit(WDM_IN_USE, &desc->flags);
433 wake_up_all(&desc->wait); /* for wdm_wait_for_response() */
434 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
435 rv = usb_translate_errors(rv);
436 goto out_free_mem_pm;
437 } else {
438 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d\n",
439 le16_to_cpu(req->wIndex));
440 }
441
442 usb_autopm_put_interface(desc->intf);
443 mutex_unlock(&desc->wlock);
444 return count;
445
446 out_free_mem_pm:
447 usb_autopm_put_interface(desc->intf);
448 out_free_mem_lock:
449 mutex_unlock(&desc->wlock);
450 out_free_mem:
451 kfree(buf);
452 return rv;
453 }
454
455 /*
456 * Submit the read urb if resp_count is non-zero.
457 *
458 * Called with desc->iuspin locked
459 */
460 static int service_outstanding_interrupt(struct wdm_device *desc)
461 {
462 int rv = 0;
463
464 /* submit read urb only if the device is waiting for it */
465 if (!desc->resp_count || !--desc->resp_count)
466 goto out;
467
468 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
469 rv = -ENODEV;
470 goto out;
471 }
472 if (test_bit(WDM_RESETTING, &desc->flags)) {
473 rv = -EIO;
474 goto out;
475 }
476
477 set_bit(WDM_RESPONDING, &desc->flags);
478 spin_unlock_irq(&desc->iuspin);
479 rv = usb_submit_urb(desc->response, GFP_KERNEL);
480 spin_lock_irq(&desc->iuspin);
481 if (rv) {
482 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
483 dev_err(&desc->intf->dev,
484 "usb_submit_urb failed with result %d\n", rv);
485
486 /* make sure the next notification trigger a submit */
487 clear_bit(WDM_RESPONDING, &desc->flags);
488 desc->resp_count = 0;
489 }
490 out:
491 return rv;
492 }
493
494 static ssize_t wdm_read
495 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
496 {
497 int rv, cntr;
498 int i = 0;
499 struct wdm_device *desc = file->private_data;
500
501
502 rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
503 if (rv < 0)
504 return -ERESTARTSYS;
505
506 cntr = READ_ONCE(desc->length);
507 if (cntr == 0) {
508 desc->read = 0;
509 retry:
510 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
511 rv = -ENODEV;
512 goto err;
513 }
514 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
515 clear_bit(WDM_OVERFLOW, &desc->flags);
516 rv = -ENOBUFS;
517 goto err;
518 }
519 i++;
520 if (file->f_flags & O_NONBLOCK) {
521 if (!test_bit(WDM_READ, &desc->flags)) {
522 rv = -EAGAIN;
523 goto err;
524 }
525 rv = 0;
526 } else {
527 rv = wait_event_interruptible(desc->wait,
528 test_bit(WDM_READ, &desc->flags));
529 }
530
531 /* may have happened while we slept */
532 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
533 rv = -ENODEV;
534 goto err;
535 }
536 if (test_bit(WDM_RESETTING, &desc->flags)) {
537 rv = -EIO;
538 goto err;
539 }
540 usb_mark_last_busy(interface_to_usbdev(desc->intf));
541 if (rv < 0) {
542 rv = -ERESTARTSYS;
543 goto err;
544 }
545
546 spin_lock_irq(&desc->iuspin);
547
548 if (desc->rerr) { /* read completed, error happened */
549 rv = usb_translate_errors(desc->rerr);
550 desc->rerr = 0;
551 spin_unlock_irq(&desc->iuspin);
552 goto err;
553 }
554 /*
555 * recheck whether we've lost the race
556 * against the completion handler
557 */
558 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
559 spin_unlock_irq(&desc->iuspin);
560 goto retry;
561 }
562
563 if (!desc->reslength) { /* zero length read */
564 dev_dbg(&desc->intf->dev, "zero length - clearing WDM_READ\n");
565 clear_bit(WDM_READ, &desc->flags);
566 rv = service_outstanding_interrupt(desc);
567 spin_unlock_irq(&desc->iuspin);
568 if (rv < 0)
569 goto err;
570 goto retry;
571 }
572 cntr = desc->length;
573 spin_unlock_irq(&desc->iuspin);
574 }
575
576 if (cntr > count)
577 cntr = count;
578 rv = copy_to_user(buffer, desc->ubuf, cntr);
579 if (rv > 0) {
580 rv = -EFAULT;
581 goto err;
582 }
583
584 spin_lock_irq(&desc->iuspin);
585
586 for (i = 0; i < desc->length - cntr; i++)
587 desc->ubuf[i] = desc->ubuf[i + cntr];
588
589 desc->length -= cntr;
590 /* in case we had outstanding data */
591 if (!desc->length) {
592 clear_bit(WDM_READ, &desc->flags);
593 service_outstanding_interrupt(desc);
594 }
595 spin_unlock_irq(&desc->iuspin);
596 rv = cntr;
597
598 err:
599 mutex_unlock(&desc->rlock);
600 return rv;
601 }
602
603 static int wdm_wait_for_response(struct file *file, long timeout)
604 {
605 struct wdm_device *desc = file->private_data;
606 long rv; /* Use long here because (int) MAX_SCHEDULE_TIMEOUT < 0. */
607
608 /*
609 * Needs both flags. We cannot do with one because resetting it would
610 * cause a race with write() yet we need to signal a disconnect.
611 */
612 rv = wait_event_interruptible_timeout(desc->wait,
613 !test_bit(WDM_IN_USE, &desc->flags) ||
614 test_bit(WDM_DISCONNECTING, &desc->flags),
615 timeout);
616
617 /*
618 * To report the correct error. This is best effort.
619 * We are inevitably racing with the hardware.
620 */
621 if (test_bit(WDM_DISCONNECTING, &desc->flags))
622 return -ENODEV;
623 if (!rv)
624 return -EIO;
625 if (rv < 0)
626 return -EINTR;
627
628 spin_lock_irq(&desc->iuspin);
629 rv = desc->werr;
630 desc->werr = 0;
631 spin_unlock_irq(&desc->iuspin);
632
633 return usb_translate_errors(rv);
634
635 }
636
637 /*
638 * You need to send a signal when you react to malicious or defective hardware.
639 * Also, don't abort when fsync() returned -EINVAL, for older kernels which do
640 * not implement wdm_flush() will return -EINVAL.
641 */
642 static int wdm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
643 {
644 return wdm_wait_for_response(file, MAX_SCHEDULE_TIMEOUT);
645 }
646
647 /*
648 * Same with wdm_fsync(), except it uses finite timeout in order to react to
649 * malicious or defective hardware which ceased communication after close() was
650 * implicitly called due to process termination.
651 */
652 static int wdm_flush(struct file *file, fl_owner_t id)
653 {
654 return wdm_wait_for_response(file, WDM_FLUSH_TIMEOUT);
655 }
656
657 static __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait)
658 {
659 struct wdm_device *desc = file->private_data;
660 unsigned long flags;
661 __poll_t mask = 0;
662
663 spin_lock_irqsave(&desc->iuspin, flags);
664 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
665 mask = EPOLLHUP | EPOLLERR;
666 spin_unlock_irqrestore(&desc->iuspin, flags);
667 goto desc_out;
668 }
669 if (test_bit(WDM_READ, &desc->flags))
670 mask = EPOLLIN | EPOLLRDNORM;
671 if (desc->rerr || desc->werr)
672 mask |= EPOLLERR;
673 if (!test_bit(WDM_IN_USE, &desc->flags))
674 mask |= EPOLLOUT | EPOLLWRNORM;
675 spin_unlock_irqrestore(&desc->iuspin, flags);
676
677 poll_wait(file, &desc->wait, wait);
678
679 desc_out:
680 return mask;
681 }
682
683 static int wdm_open(struct inode *inode, struct file *file)
684 {
685 int minor = iminor(inode);
686 int rv = -ENODEV;
687 struct usb_interface *intf;
688 struct wdm_device *desc;
689
690 mutex_lock(&wdm_mutex);
691 desc = wdm_find_device_by_minor(minor);
692 if (!desc)
693 goto out;
694
695 intf = desc->intf;
696 if (test_bit(WDM_DISCONNECTING, &desc->flags))
697 goto out;
698 file->private_data = desc;
699
700 rv = usb_autopm_get_interface(desc->intf);
701 if (rv < 0) {
702 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
703 goto out;
704 }
705
706 /* using write lock to protect desc->count */
707 mutex_lock(&desc->wlock);
708 if (!desc->count++) {
709 desc->werr = 0;
710 desc->rerr = 0;
711 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
712 if (rv < 0) {
713 desc->count--;
714 dev_err(&desc->intf->dev,
715 "Error submitting int urb - %d\n", rv);
716 rv = usb_translate_errors(rv);
717 }
718 } else {
719 rv = 0;
720 }
721 mutex_unlock(&desc->wlock);
722 if (desc->count == 1)
723 desc->manage_power(intf, 1);
724 usb_autopm_put_interface(desc->intf);
725 out:
726 mutex_unlock(&wdm_mutex);
727 return rv;
728 }
729
730 static int wdm_release(struct inode *inode, struct file *file)
731 {
732 struct wdm_device *desc = file->private_data;
733
734 mutex_lock(&wdm_mutex);
735
736 /* using write lock to protect desc->count */
737 mutex_lock(&desc->wlock);
738 desc->count--;
739 mutex_unlock(&desc->wlock);
740
741 if (!desc->count) {
742 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
743 dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n");
744 kill_urbs(desc);
745 spin_lock_irq(&desc->iuspin);
746 desc->resp_count = 0;
747 spin_unlock_irq(&desc->iuspin);
748 desc->manage_power(desc->intf, 0);
749 } else {
750 /* must avoid dev_printk here as desc->intf is invalid */
751 pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
752 cleanup(desc);
753 }
754 }
755 mutex_unlock(&wdm_mutex);
756 return 0;
757 }
758
759 static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
760 {
761 struct wdm_device *desc = file->private_data;
762 int rv = 0;
763
764 switch (cmd) {
765 case IOCTL_WDM_MAX_COMMAND:
766 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
767 rv = -EFAULT;
768 break;
769 default:
770 rv = -ENOTTY;
771 }
772 return rv;
773 }
774
775 static const struct file_operations wdm_fops = {
776 .owner = THIS_MODULE,
777 .read = wdm_read,
778 .write = wdm_write,
779 .fsync = wdm_fsync,
780 .open = wdm_open,
781 .flush = wdm_flush,
782 .release = wdm_release,
783 .poll = wdm_poll,
784 .unlocked_ioctl = wdm_ioctl,
785 .compat_ioctl = compat_ptr_ioctl,
786 .llseek = noop_llseek,
787 };
788
789 static struct usb_class_driver wdm_class = {
790 .name = "cdc-wdm%d",
791 .fops = &wdm_fops,
792 .minor_base = WDM_MINOR_BASE,
793 };
794
795 /* --- error handling --- */
796 static void wdm_rxwork(struct work_struct *work)
797 {
798 struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
799 unsigned long flags;
800 int rv = 0;
801 int responding;
802
803 spin_lock_irqsave(&desc->iuspin, flags);
804 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
805 spin_unlock_irqrestore(&desc->iuspin, flags);
806 } else {
807 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
808 spin_unlock_irqrestore(&desc->iuspin, flags);
809 if (!responding)
810 rv = usb_submit_urb(desc->response, GFP_KERNEL);
811 if (rv < 0 && rv != -EPERM) {
812 spin_lock_irqsave(&desc->iuspin, flags);
813 clear_bit(WDM_RESPONDING, &desc->flags);
814 if (!test_bit(WDM_DISCONNECTING, &desc->flags))
815 schedule_work(&desc->rxwork);
816 spin_unlock_irqrestore(&desc->iuspin, flags);
817 }
818 }
819 }
820
821 static void service_interrupt_work(struct work_struct *work)
822 {
823 struct wdm_device *desc;
824
825 desc = container_of(work, struct wdm_device, service_outs_intr);
826
827 spin_lock_irq(&desc->iuspin);
828 service_outstanding_interrupt(desc);
829 if (!desc->resp_count) {
830 set_bit(WDM_READ, &desc->flags);
831 wake_up(&desc->wait);
832 }
833 spin_unlock_irq(&desc->iuspin);
834 }
835
836 /* --- hotplug --- */
837
838 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
839 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
840 {
841 int rv = -ENOMEM;
842 struct wdm_device *desc;
843
844 desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
845 if (!desc)
846 goto out;
847 INIT_LIST_HEAD(&desc->device_list);
848 mutex_init(&desc->rlock);
849 mutex_init(&desc->wlock);
850 spin_lock_init(&desc->iuspin);
851 init_waitqueue_head(&desc->wait);
852 desc->wMaxCommand = bufsize;
853 /* this will be expanded and needed in hardware endianness */
854 desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
855 desc->intf = intf;
856 INIT_WORK(&desc->rxwork, wdm_rxwork);
857 INIT_WORK(&desc->service_outs_intr, service_interrupt_work);
858
859 rv = -EINVAL;
860 if (!usb_endpoint_is_int_in(ep))
861 goto err;
862
863 desc->wMaxPacketSize = usb_endpoint_maxp(ep);
864
865 desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
866 if (!desc->orq)
867 goto err;
868 desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
869 if (!desc->irq)
870 goto err;
871
872 desc->validity = usb_alloc_urb(0, GFP_KERNEL);
873 if (!desc->validity)
874 goto err;
875
876 desc->response = usb_alloc_urb(0, GFP_KERNEL);
877 if (!desc->response)
878 goto err;
879
880 desc->command = usb_alloc_urb(0, GFP_KERNEL);
881 if (!desc->command)
882 goto err;
883
884 desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
885 if (!desc->ubuf)
886 goto err;
887
888 desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
889 if (!desc->sbuf)
890 goto err;
891
892 desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
893 if (!desc->inbuf)
894 goto err;
895
896 usb_fill_int_urb(
897 desc->validity,
898 interface_to_usbdev(intf),
899 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
900 desc->sbuf,
901 desc->wMaxPacketSize,
902 wdm_int_callback,
903 desc,
904 ep->bInterval
905 );
906
907 desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
908 desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
909 desc->irq->wValue = 0;
910 desc->irq->wIndex = desc->inum; /* already converted */
911 desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
912
913 usb_fill_control_urb(
914 desc->response,
915 interface_to_usbdev(intf),
916 /* using common endpoint 0 */
917 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
918 (unsigned char *)desc->irq,
919 desc->inbuf,
920 desc->wMaxCommand,
921 wdm_in_callback,
922 desc
923 );
924
925 desc->manage_power = manage_power;
926
927 spin_lock(&wdm_device_list_lock);
928 list_add(&desc->device_list, &wdm_device_list);
929 spin_unlock(&wdm_device_list_lock);
930
931 rv = usb_register_dev(intf, &wdm_class);
932 if (rv < 0)
933 goto err;
934 else
935 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
936 out:
937 return rv;
938 err:
939 spin_lock(&wdm_device_list_lock);
940 list_del(&desc->device_list);
941 spin_unlock(&wdm_device_list_lock);
942 cleanup(desc);
943 return rv;
944 }
945
946 static int wdm_manage_power(struct usb_interface *intf, int on)
947 {
948 /* need autopm_get/put here to ensure the usbcore sees the new value */
949 int rv = usb_autopm_get_interface(intf);
950
951 intf->needs_remote_wakeup = on;
952 if (!rv)
953 usb_autopm_put_interface(intf);
954 return 0;
955 }
956
957 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
958 {
959 int rv = -EINVAL;
960 struct usb_host_interface *iface;
961 struct usb_endpoint_descriptor *ep;
962 struct usb_cdc_parsed_header hdr;
963 u8 *buffer = intf->altsetting->extra;
964 int buflen = intf->altsetting->extralen;
965 u16 maxcom = WDM_DEFAULT_BUFSIZE;
966
967 if (!buffer)
968 goto err;
969
970 cdc_parse_cdc_header(&hdr, intf, buffer, buflen);
971
972 if (hdr.usb_cdc_dmm_desc)
973 maxcom = le16_to_cpu(hdr.usb_cdc_dmm_desc->wMaxCommand);
974
975 iface = intf->cur_altsetting;
976 if (iface->desc.bNumEndpoints != 1)
977 goto err;
978 ep = &iface->endpoint[0].desc;
979
980 rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
981
982 err:
983 return rv;
984 }
985
986 /**
987 * usb_cdc_wdm_register - register a WDM subdriver
988 * @intf: usb interface the subdriver will associate with
989 * @ep: interrupt endpoint to monitor for notifications
990 * @bufsize: maximum message size to support for read/write
991 * @manage_power: call-back invoked during open and release to
992 * manage the device's power
993 * Create WDM usb class character device and associate it with intf
994 * without binding, allowing another driver to manage the interface.
995 *
996 * The subdriver will manage the given interrupt endpoint exclusively
997 * and will issue control requests referring to the given intf. It
998 * will otherwise avoid interferring, and in particular not do
999 * usb_set_intfdata/usb_get_intfdata on intf.
1000 *
1001 * The return value is a pointer to the subdriver's struct usb_driver.
1002 * The registering driver is responsible for calling this subdriver's
1003 * disconnect, suspend, resume, pre_reset and post_reset methods from
1004 * its own.
1005 */
1006 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
1007 struct usb_endpoint_descriptor *ep,
1008 int bufsize,
1009 int (*manage_power)(struct usb_interface *, int))
1010 {
1011 int rv;
1012
1013 rv = wdm_create(intf, ep, bufsize, manage_power);
1014 if (rv < 0)
1015 goto err;
1016
1017 return &wdm_driver;
1018 err:
1019 return ERR_PTR(rv);
1020 }
1021 EXPORT_SYMBOL(usb_cdc_wdm_register);
1022
1023 static void wdm_disconnect(struct usb_interface *intf)
1024 {
1025 struct wdm_device *desc;
1026 unsigned long flags;
1027
1028 usb_deregister_dev(intf, &wdm_class);
1029 desc = wdm_find_device(intf);
1030 mutex_lock(&wdm_mutex);
1031
1032 /* the spinlock makes sure no new urbs are generated in the callbacks */
1033 spin_lock_irqsave(&desc->iuspin, flags);
1034 set_bit(WDM_DISCONNECTING, &desc->flags);
1035 set_bit(WDM_READ, &desc->flags);
1036 spin_unlock_irqrestore(&desc->iuspin, flags);
1037 wake_up_all(&desc->wait);
1038 mutex_lock(&desc->rlock);
1039 mutex_lock(&desc->wlock);
1040 cancel_work_sync(&desc->rxwork);
1041 cancel_work_sync(&desc->service_outs_intr);
1042 kill_urbs(desc);
1043 mutex_unlock(&desc->wlock);
1044 mutex_unlock(&desc->rlock);
1045
1046 /* the desc->intf pointer used as list key is now invalid */
1047 spin_lock(&wdm_device_list_lock);
1048 list_del(&desc->device_list);
1049 spin_unlock(&wdm_device_list_lock);
1050
1051 if (!desc->count)
1052 cleanup(desc);
1053 else
1054 dev_dbg(&intf->dev, "%d open files - postponing cleanup\n", desc->count);
1055 mutex_unlock(&wdm_mutex);
1056 }
1057
1058 #ifdef CONFIG_PM
1059 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
1060 {
1061 struct wdm_device *desc = wdm_find_device(intf);
1062 int rv = 0;
1063
1064 dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
1065
1066 /* if this is an autosuspend the caller does the locking */
1067 if (!PMSG_IS_AUTO(message)) {
1068 mutex_lock(&desc->rlock);
1069 mutex_lock(&desc->wlock);
1070 }
1071 spin_lock_irq(&desc->iuspin);
1072
1073 if (PMSG_IS_AUTO(message) &&
1074 (test_bit(WDM_IN_USE, &desc->flags)
1075 || test_bit(WDM_RESPONDING, &desc->flags))) {
1076 spin_unlock_irq(&desc->iuspin);
1077 rv = -EBUSY;
1078 } else {
1079
1080 set_bit(WDM_SUSPENDING, &desc->flags);
1081 spin_unlock_irq(&desc->iuspin);
1082 /* callback submits work - order is essential */
1083 kill_urbs(desc);
1084 cancel_work_sync(&desc->rxwork);
1085 cancel_work_sync(&desc->service_outs_intr);
1086 }
1087 if (!PMSG_IS_AUTO(message)) {
1088 mutex_unlock(&desc->wlock);
1089 mutex_unlock(&desc->rlock);
1090 }
1091
1092 return rv;
1093 }
1094 #endif
1095
1096 static int recover_from_urb_loss(struct wdm_device *desc)
1097 {
1098 int rv = 0;
1099
1100 if (desc->count) {
1101 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1102 if (rv < 0)
1103 dev_err(&desc->intf->dev,
1104 "Error resume submitting int urb - %d\n", rv);
1105 }
1106 return rv;
1107 }
1108
1109 #ifdef CONFIG_PM
1110 static int wdm_resume(struct usb_interface *intf)
1111 {
1112 struct wdm_device *desc = wdm_find_device(intf);
1113 int rv;
1114
1115 dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1116
1117 clear_bit(WDM_SUSPENDING, &desc->flags);
1118 rv = recover_from_urb_loss(desc);
1119
1120 return rv;
1121 }
1122 #endif
1123
1124 static int wdm_pre_reset(struct usb_interface *intf)
1125 {
1126 struct wdm_device *desc = wdm_find_device(intf);
1127
1128 /*
1129 * we notify everybody using poll of
1130 * an exceptional situation
1131 * must be done before recovery lest a spontaneous
1132 * message from the device is lost
1133 */
1134 spin_lock_irq(&desc->iuspin);
1135 set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */
1136 set_bit(WDM_READ, &desc->flags); /* unblock read */
1137 clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */
1138 desc->rerr = -EINTR;
1139 spin_unlock_irq(&desc->iuspin);
1140 wake_up_all(&desc->wait);
1141 mutex_lock(&desc->rlock);
1142 mutex_lock(&desc->wlock);
1143 kill_urbs(desc);
1144 cancel_work_sync(&desc->rxwork);
1145 cancel_work_sync(&desc->service_outs_intr);
1146 return 0;
1147 }
1148
1149 static int wdm_post_reset(struct usb_interface *intf)
1150 {
1151 struct wdm_device *desc = wdm_find_device(intf);
1152 int rv;
1153
1154 clear_bit(WDM_OVERFLOW, &desc->flags);
1155 clear_bit(WDM_RESETTING, &desc->flags);
1156 rv = recover_from_urb_loss(desc);
1157 mutex_unlock(&desc->wlock);
1158 mutex_unlock(&desc->rlock);
1159 return rv;
1160 }
1161
1162 static struct usb_driver wdm_driver = {
1163 .name = "cdc_wdm",
1164 .probe = wdm_probe,
1165 .disconnect = wdm_disconnect,
1166 #ifdef CONFIG_PM
1167 .suspend = wdm_suspend,
1168 .resume = wdm_resume,
1169 .reset_resume = wdm_resume,
1170 #endif
1171 .pre_reset = wdm_pre_reset,
1172 .post_reset = wdm_post_reset,
1173 .id_table = wdm_ids,
1174 .supports_autosuspend = 1,
1175 .disable_hub_initiated_lpm = 1,
1176 };
1177
1178 module_usb_driver(wdm_driver);
1179
1180 MODULE_AUTHOR(DRIVER_AUTHOR);
1181 MODULE_DESCRIPTION(DRIVER_DESC);
1182 MODULE_LICENSE("GPL");
Linux with added FPC-III support