Version:  2.0.40 2.2.26 2.4.37 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1

Linux/drivers/usb/class/cdc-wdm.c

  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/ioctl.h>
 17 #include <linux/slab.h>
 18 #include <linux/module.h>
 19 #include <linux/mutex.h>
 20 #include <linux/uaccess.h>
 21 #include <linux/bitops.h>
 22 #include <linux/poll.h>
 23 #include <linux/usb.h>
 24 #include <linux/usb/cdc.h>
 25 #include <asm/byteorder.h>
 26 #include <asm/unaligned.h>
 27 #include <linux/usb/cdc-wdm.h>
 28 
 29 /*
 30  * Version Information
 31  */
 32 #define DRIVER_VERSION "v0.03"
 33 #define DRIVER_AUTHOR "Oliver Neukum"
 34 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
 35 
 36 static const struct usb_device_id wdm_ids[] = {
 37         {
 38                 .match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
 39                                  USB_DEVICE_ID_MATCH_INT_SUBCLASS,
 40                 .bInterfaceClass = USB_CLASS_COMM,
 41                 .bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
 42         },
 43         { }
 44 };
 45 
 46 MODULE_DEVICE_TABLE (usb, wdm_ids);
 47 
 48 #define WDM_MINOR_BASE  176
 49 
 50 
 51 #define WDM_IN_USE              1
 52 #define WDM_DISCONNECTING       2
 53 #define WDM_RESULT              3
 54 #define WDM_READ                4
 55 #define WDM_INT_STALL           5
 56 #define WDM_POLL_RUNNING        6
 57 #define WDM_RESPONDING          7
 58 #define WDM_SUSPENDING          8
 59 #define WDM_RESETTING           9
 60 #define WDM_OVERFLOW            10
 61 
 62 #define WDM_MAX                 16
 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         int                     werr;
103         int                     rerr;
104         int                     resp_count;
105 
106         struct list_head        device_list;
107         int                     (*manage_power)(struct usb_interface *, int);
108 };
109 
110 static struct usb_driver wdm_driver;
111 
112 /* return intfdata if we own the interface, else look up intf in the list */
113 static struct wdm_device *wdm_find_device(struct usb_interface *intf)
114 {
115         struct wdm_device *desc;
116 
117         spin_lock(&wdm_device_list_lock);
118         list_for_each_entry(desc, &wdm_device_list, device_list)
119                 if (desc->intf == intf)
120                         goto found;
121         desc = NULL;
122 found:
123         spin_unlock(&wdm_device_list_lock);
124 
125         return desc;
126 }
127 
128 static struct wdm_device *wdm_find_device_by_minor(int minor)
129 {
130         struct wdm_device *desc;
131 
132         spin_lock(&wdm_device_list_lock);
133         list_for_each_entry(desc, &wdm_device_list, device_list)
134                 if (desc->intf->minor == minor)
135                         goto found;
136         desc = NULL;
137 found:
138         spin_unlock(&wdm_device_list_lock);
139 
140         return desc;
141 }
142 
143 /* --- callbacks --- */
144 static void wdm_out_callback(struct urb *urb)
145 {
146         struct wdm_device *desc;
147         desc = urb->context;
148         spin_lock(&desc->iuspin);
149         desc->werr = urb->status;
150         spin_unlock(&desc->iuspin);
151         kfree(desc->outbuf);
152         desc->outbuf = NULL;
153         clear_bit(WDM_IN_USE, &desc->flags);
154         wake_up(&desc->wait);
155 }
156 
157 static void wdm_in_callback(struct urb *urb)
158 {
159         struct wdm_device *desc = urb->context;
160         int status = urb->status;
161         int length = urb->actual_length;
162 
163         spin_lock(&desc->iuspin);
164         clear_bit(WDM_RESPONDING, &desc->flags);
165 
166         if (status) {
167                 switch (status) {
168                 case -ENOENT:
169                         dev_dbg(&desc->intf->dev,
170                                 "nonzero urb status received: -ENOENT");
171                         goto skip_error;
172                 case -ECONNRESET:
173                         dev_dbg(&desc->intf->dev,
174                                 "nonzero urb status received: -ECONNRESET");
175                         goto skip_error;
176                 case -ESHUTDOWN:
177                         dev_dbg(&desc->intf->dev,
178                                 "nonzero urb status received: -ESHUTDOWN");
179                         goto skip_error;
180                 case -EPIPE:
181                         dev_err(&desc->intf->dev,
182                                 "nonzero urb status received: -EPIPE\n");
183                         break;
184                 default:
185                         dev_err(&desc->intf->dev,
186                                 "Unexpected error %d\n", status);
187                         break;
188                 }
189         }
190 
191         desc->rerr = status;
192         if (length + desc->length > desc->wMaxCommand) {
193                 /* The buffer would overflow */
194                 set_bit(WDM_OVERFLOW, &desc->flags);
195         } else {
196                 /* we may already be in overflow */
197                 if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
198                         memmove(desc->ubuf + desc->length, desc->inbuf, length);
199                         desc->length += length;
200                         desc->reslength = length;
201                 }
202         }
203 skip_error:
204         wake_up(&desc->wait);
205 
206         set_bit(WDM_READ, &desc->flags);
207         spin_unlock(&desc->iuspin);
208 }
209 
210 static void wdm_int_callback(struct urb *urb)
211 {
212         int rv = 0;
213         int responding;
214         int status = urb->status;
215         struct wdm_device *desc;
216         struct usb_cdc_notification *dr;
217 
218         desc = urb->context;
219         dr = (struct usb_cdc_notification *)desc->sbuf;
220 
221         if (status) {
222                 switch (status) {
223                 case -ESHUTDOWN:
224                 case -ENOENT:
225                 case -ECONNRESET:
226                         return; /* unplug */
227                 case -EPIPE:
228                         set_bit(WDM_INT_STALL, &desc->flags);
229                         dev_err(&desc->intf->dev, "Stall on int endpoint\n");
230                         goto sw; /* halt is cleared in work */
231                 default:
232                         dev_err(&desc->intf->dev,
233                                 "nonzero urb status received: %d\n", status);
234                         break;
235                 }
236         }
237 
238         if (urb->actual_length < sizeof(struct usb_cdc_notification)) {
239                 dev_err(&desc->intf->dev, "wdm_int_callback - %d bytes\n",
240                         urb->actual_length);
241                 goto exit;
242         }
243 
244         switch (dr->bNotificationType) {
245         case USB_CDC_NOTIFY_RESPONSE_AVAILABLE:
246                 dev_dbg(&desc->intf->dev,
247                         "NOTIFY_RESPONSE_AVAILABLE received: index %d len %d",
248                         le16_to_cpu(dr->wIndex), le16_to_cpu(dr->wLength));
249                 break;
250 
251         case USB_CDC_NOTIFY_NETWORK_CONNECTION:
252 
253                 dev_dbg(&desc->intf->dev,
254                         "NOTIFY_NETWORK_CONNECTION %s network",
255                         dr->wValue ? "connected to" : "disconnected from");
256                 goto exit;
257         case USB_CDC_NOTIFY_SPEED_CHANGE:
258                 dev_dbg(&desc->intf->dev, "SPEED_CHANGE received (len %u)",
259                         urb->actual_length);
260                 goto exit;
261         default:
262                 clear_bit(WDM_POLL_RUNNING, &desc->flags);
263                 dev_err(&desc->intf->dev,
264                         "unknown notification %d received: index %d len %d\n",
265                         dr->bNotificationType,
266                         le16_to_cpu(dr->wIndex),
267                         le16_to_cpu(dr->wLength));
268                 goto exit;
269         }
270 
271         spin_lock(&desc->iuspin);
272         responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
273         if (!desc->resp_count++ && !responding
274                 && !test_bit(WDM_DISCONNECTING, &desc->flags)
275                 && !test_bit(WDM_SUSPENDING, &desc->flags)) {
276                 rv = usb_submit_urb(desc->response, GFP_ATOMIC);
277                 dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
278                         __func__, rv);
279         }
280         spin_unlock(&desc->iuspin);
281         if (rv < 0) {
282                 clear_bit(WDM_RESPONDING, &desc->flags);
283                 if (rv == -EPERM)
284                         return;
285                 if (rv == -ENOMEM) {
286 sw:
287                         rv = schedule_work(&desc->rxwork);
288                         if (rv)
289                                 dev_err(&desc->intf->dev,
290                                         "Cannot schedule work\n");
291                 }
292         }
293 exit:
294         rv = usb_submit_urb(urb, GFP_ATOMIC);
295         if (rv)
296                 dev_err(&desc->intf->dev,
297                         "%s - usb_submit_urb failed with result %d\n",
298                         __func__, rv);
299 
300 }
301 
302 static void kill_urbs(struct wdm_device *desc)
303 {
304         /* the order here is essential */
305         usb_kill_urb(desc->command);
306         usb_kill_urb(desc->validity);
307         usb_kill_urb(desc->response);
308 }
309 
310 static void free_urbs(struct wdm_device *desc)
311 {
312         usb_free_urb(desc->validity);
313         usb_free_urb(desc->response);
314         usb_free_urb(desc->command);
315 }
316 
317 static void cleanup(struct wdm_device *desc)
318 {
319         kfree(desc->sbuf);
320         kfree(desc->inbuf);
321         kfree(desc->orq);
322         kfree(desc->irq);
323         kfree(desc->ubuf);
324         free_urbs(desc);
325         kfree(desc);
326 }
327 
328 static ssize_t wdm_write
329 (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
330 {
331         u8 *buf;
332         int rv = -EMSGSIZE, r, we;
333         struct wdm_device *desc = file->private_data;
334         struct usb_ctrlrequest *req;
335 
336         if (count > desc->wMaxCommand)
337                 count = desc->wMaxCommand;
338 
339         spin_lock_irq(&desc->iuspin);
340         we = desc->werr;
341         desc->werr = 0;
342         spin_unlock_irq(&desc->iuspin);
343         if (we < 0)
344                 return usb_translate_errors(we);
345 
346         buf = kmalloc(count, GFP_KERNEL);
347         if (!buf) {
348                 rv = -ENOMEM;
349                 goto outnl;
350         }
351 
352         r = copy_from_user(buf, buffer, count);
353         if (r > 0) {
354                 rv = -EFAULT;
355                 goto out_free_mem;
356         }
357 
358         /* concurrent writes and disconnect */
359         r = mutex_lock_interruptible(&desc->wlock);
360         rv = -ERESTARTSYS;
361         if (r)
362                 goto out_free_mem;
363 
364         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
365                 rv = -ENODEV;
366                 goto out_free_mem_lock;
367         }
368 
369         r = usb_autopm_get_interface(desc->intf);
370         if (r < 0) {
371                 rv = usb_translate_errors(r);
372                 goto out_free_mem_lock;
373         }
374 
375         if (!(file->f_flags & O_NONBLOCK))
376                 r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
377                                                                 &desc->flags));
378         else
379                 if (test_bit(WDM_IN_USE, &desc->flags))
380                         r = -EAGAIN;
381 
382         if (test_bit(WDM_RESETTING, &desc->flags))
383                 r = -EIO;
384 
385         if (r < 0) {
386                 rv = r;
387                 goto out_free_mem_pm;
388         }
389 
390         req = desc->orq;
391         usb_fill_control_urb(
392                 desc->command,
393                 interface_to_usbdev(desc->intf),
394                 /* using common endpoint 0 */
395                 usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
396                 (unsigned char *)req,
397                 buf,
398                 count,
399                 wdm_out_callback,
400                 desc
401         );
402 
403         req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
404                              USB_RECIP_INTERFACE);
405         req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
406         req->wValue = 0;
407         req->wIndex = desc->inum; /* already converted */
408         req->wLength = cpu_to_le16(count);
409         set_bit(WDM_IN_USE, &desc->flags);
410         desc->outbuf = buf;
411 
412         rv = usb_submit_urb(desc->command, GFP_KERNEL);
413         if (rv < 0) {
414                 desc->outbuf = NULL;
415                 clear_bit(WDM_IN_USE, &desc->flags);
416                 dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
417                 rv = usb_translate_errors(rv);
418                 goto out_free_mem_pm;
419         } else {
420                 dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
421                         le16_to_cpu(req->wIndex));
422         }
423 
424         usb_autopm_put_interface(desc->intf);
425         mutex_unlock(&desc->wlock);
426 outnl:
427         return rv < 0 ? rv : count;
428 
429 out_free_mem_pm:
430         usb_autopm_put_interface(desc->intf);
431 out_free_mem_lock:
432         mutex_unlock(&desc->wlock);
433 out_free_mem:
434         kfree(buf);
435         return rv;
436 }
437 
438 /*
439  * clear WDM_READ flag and possibly submit the read urb if resp_count
440  * is non-zero.
441  *
442  * Called with desc->iuspin locked
443  */
444 static int clear_wdm_read_flag(struct wdm_device *desc)
445 {
446         int rv = 0;
447 
448         clear_bit(WDM_READ, &desc->flags);
449 
450         /* submit read urb only if the device is waiting for it */
451         if (!desc->resp_count || !--desc->resp_count)
452                 goto out;
453 
454         set_bit(WDM_RESPONDING, &desc->flags);
455         spin_unlock_irq(&desc->iuspin);
456         rv = usb_submit_urb(desc->response, GFP_KERNEL);
457         spin_lock_irq(&desc->iuspin);
458         if (rv) {
459                 dev_err(&desc->intf->dev,
460                         "usb_submit_urb failed with result %d\n", rv);
461 
462                 /* make sure the next notification trigger a submit */
463                 clear_bit(WDM_RESPONDING, &desc->flags);
464                 desc->resp_count = 0;
465         }
466 out:
467         return rv;
468 }
469 
470 static ssize_t wdm_read
471 (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
472 {
473         int rv, cntr;
474         int i = 0;
475         struct wdm_device *desc = file->private_data;
476 
477 
478         rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
479         if (rv < 0)
480                 return -ERESTARTSYS;
481 
482         cntr = ACCESS_ONCE(desc->length);
483         if (cntr == 0) {
484                 desc->read = 0;
485 retry:
486                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
487                         rv = -ENODEV;
488                         goto err;
489                 }
490                 if (test_bit(WDM_OVERFLOW, &desc->flags)) {
491                         clear_bit(WDM_OVERFLOW, &desc->flags);
492                         rv = -ENOBUFS;
493                         goto err;
494                 }
495                 i++;
496                 if (file->f_flags & O_NONBLOCK) {
497                         if (!test_bit(WDM_READ, &desc->flags)) {
498                                 rv = cntr ? cntr : -EAGAIN;
499                                 goto err;
500                         }
501                         rv = 0;
502                 } else {
503                         rv = wait_event_interruptible(desc->wait,
504                                 test_bit(WDM_READ, &desc->flags));
505                 }
506 
507                 /* may have happened while we slept */
508                 if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
509                         rv = -ENODEV;
510                         goto err;
511                 }
512                 if (test_bit(WDM_RESETTING, &desc->flags)) {
513                         rv = -EIO;
514                         goto err;
515                 }
516                 usb_mark_last_busy(interface_to_usbdev(desc->intf));
517                 if (rv < 0) {
518                         rv = -ERESTARTSYS;
519                         goto err;
520                 }
521 
522                 spin_lock_irq(&desc->iuspin);
523 
524                 if (desc->rerr) { /* read completed, error happened */
525                         rv = usb_translate_errors(desc->rerr);
526                         desc->rerr = 0;
527                         spin_unlock_irq(&desc->iuspin);
528                         goto err;
529                 }
530                 /*
531                  * recheck whether we've lost the race
532                  * against the completion handler
533                  */
534                 if (!test_bit(WDM_READ, &desc->flags)) { /* lost race */
535                         spin_unlock_irq(&desc->iuspin);
536                         goto retry;
537                 }
538 
539                 if (!desc->reslength) { /* zero length read */
540                         dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__);
541                         rv = clear_wdm_read_flag(desc);
542                         spin_unlock_irq(&desc->iuspin);
543                         if (rv < 0)
544                                 goto err;
545                         goto retry;
546                 }
547                 cntr = desc->length;
548                 spin_unlock_irq(&desc->iuspin);
549         }
550 
551         if (cntr > count)
552                 cntr = count;
553         rv = copy_to_user(buffer, desc->ubuf, cntr);
554         if (rv > 0) {
555                 rv = -EFAULT;
556                 goto err;
557         }
558 
559         spin_lock_irq(&desc->iuspin);
560 
561         for (i = 0; i < desc->length - cntr; i++)
562                 desc->ubuf[i] = desc->ubuf[i + cntr];
563 
564         desc->length -= cntr;
565         /* in case we had outstanding data */
566         if (!desc->length)
567                 clear_wdm_read_flag(desc);
568         spin_unlock_irq(&desc->iuspin);
569         rv = cntr;
570 
571 err:
572         mutex_unlock(&desc->rlock);
573         return rv;
574 }
575 
576 static int wdm_flush(struct file *file, fl_owner_t id)
577 {
578         struct wdm_device *desc = file->private_data;
579 
580         wait_event(desc->wait, !test_bit(WDM_IN_USE, &desc->flags));
581 
582         /* cannot dereference desc->intf if WDM_DISCONNECTING */
583         if (desc->werr < 0 && !test_bit(WDM_DISCONNECTING, &desc->flags))
584                 dev_err(&desc->intf->dev, "Error in flush path: %d\n",
585                         desc->werr);
586 
587         return usb_translate_errors(desc->werr);
588 }
589 
590 static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
591 {
592         struct wdm_device *desc = file->private_data;
593         unsigned long flags;
594         unsigned int mask = 0;
595 
596         spin_lock_irqsave(&desc->iuspin, flags);
597         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
598                 mask = POLLHUP | POLLERR;
599                 spin_unlock_irqrestore(&desc->iuspin, flags);
600                 goto desc_out;
601         }
602         if (test_bit(WDM_READ, &desc->flags))
603                 mask = POLLIN | POLLRDNORM;
604         if (desc->rerr || desc->werr)
605                 mask |= POLLERR;
606         if (!test_bit(WDM_IN_USE, &desc->flags))
607                 mask |= POLLOUT | POLLWRNORM;
608         spin_unlock_irqrestore(&desc->iuspin, flags);
609 
610         poll_wait(file, &desc->wait, wait);
611 
612 desc_out:
613         return mask;
614 }
615 
616 static int wdm_open(struct inode *inode, struct file *file)
617 {
618         int minor = iminor(inode);
619         int rv = -ENODEV;
620         struct usb_interface *intf;
621         struct wdm_device *desc;
622 
623         mutex_lock(&wdm_mutex);
624         desc = wdm_find_device_by_minor(minor);
625         if (!desc)
626                 goto out;
627 
628         intf = desc->intf;
629         if (test_bit(WDM_DISCONNECTING, &desc->flags))
630                 goto out;
631         file->private_data = desc;
632 
633         rv = usb_autopm_get_interface(desc->intf);
634         if (rv < 0) {
635                 dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
636                 goto out;
637         }
638 
639         /* using write lock to protect desc->count */
640         mutex_lock(&desc->wlock);
641         if (!desc->count++) {
642                 desc->werr = 0;
643                 desc->rerr = 0;
644                 rv = usb_submit_urb(desc->validity, GFP_KERNEL);
645                 if (rv < 0) {
646                         desc->count--;
647                         dev_err(&desc->intf->dev,
648                                 "Error submitting int urb - %d\n", rv);
649                         rv = usb_translate_errors(rv);
650                 }
651         } else {
652                 rv = 0;
653         }
654         mutex_unlock(&desc->wlock);
655         if (desc->count == 1)
656                 desc->manage_power(intf, 1);
657         usb_autopm_put_interface(desc->intf);
658 out:
659         mutex_unlock(&wdm_mutex);
660         return rv;
661 }
662 
663 static int wdm_release(struct inode *inode, struct file *file)
664 {
665         struct wdm_device *desc = file->private_data;
666 
667         mutex_lock(&wdm_mutex);
668 
669         /* using write lock to protect desc->count */
670         mutex_lock(&desc->wlock);
671         desc->count--;
672         mutex_unlock(&desc->wlock);
673 
674         if (!desc->count) {
675                 if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
676                         dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
677                         kill_urbs(desc);
678                         spin_lock_irq(&desc->iuspin);
679                         desc->resp_count = 0;
680                         spin_unlock_irq(&desc->iuspin);
681                         desc->manage_power(desc->intf, 0);
682                 } else {
683                         /* must avoid dev_printk here as desc->intf is invalid */
684                         pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
685                         cleanup(desc);
686                 }
687         }
688         mutex_unlock(&wdm_mutex);
689         return 0;
690 }
691 
692 static long wdm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
693 {
694         struct wdm_device *desc = file->private_data;
695         int rv = 0;
696 
697         switch (cmd) {
698         case IOCTL_WDM_MAX_COMMAND:
699                 if (copy_to_user((void __user *)arg, &desc->wMaxCommand, sizeof(desc->wMaxCommand)))
700                         rv = -EFAULT;
701                 break;
702         default:
703                 rv = -ENOTTY;
704         }
705         return rv;
706 }
707 
708 static const struct file_operations wdm_fops = {
709         .owner =        THIS_MODULE,
710         .read =         wdm_read,
711         .write =        wdm_write,
712         .open =         wdm_open,
713         .flush =        wdm_flush,
714         .release =      wdm_release,
715         .poll =         wdm_poll,
716         .unlocked_ioctl = wdm_ioctl,
717         .compat_ioctl = wdm_ioctl,
718         .llseek =       noop_llseek,
719 };
720 
721 static struct usb_class_driver wdm_class = {
722         .name =         "cdc-wdm%d",
723         .fops =         &wdm_fops,
724         .minor_base =   WDM_MINOR_BASE,
725 };
726 
727 /* --- error handling --- */
728 static void wdm_rxwork(struct work_struct *work)
729 {
730         struct wdm_device *desc = container_of(work, struct wdm_device, rxwork);
731         unsigned long flags;
732         int rv = 0;
733         int responding;
734 
735         spin_lock_irqsave(&desc->iuspin, flags);
736         if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
737                 spin_unlock_irqrestore(&desc->iuspin, flags);
738         } else {
739                 responding = test_and_set_bit(WDM_RESPONDING, &desc->flags);
740                 spin_unlock_irqrestore(&desc->iuspin, flags);
741                 if (!responding)
742                         rv = usb_submit_urb(desc->response, GFP_KERNEL);
743                 if (rv < 0 && rv != -EPERM) {
744                         spin_lock_irqsave(&desc->iuspin, flags);
745                         clear_bit(WDM_RESPONDING, &desc->flags);
746                         if (!test_bit(WDM_DISCONNECTING, &desc->flags))
747                                 schedule_work(&desc->rxwork);
748                         spin_unlock_irqrestore(&desc->iuspin, flags);
749                 }
750         }
751 }
752 
753 /* --- hotplug --- */
754 
755 static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
756                 u16 bufsize, int (*manage_power)(struct usb_interface *, int))
757 {
758         int rv = -ENOMEM;
759         struct wdm_device *desc;
760 
761         desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
762         if (!desc)
763                 goto out;
764         INIT_LIST_HEAD(&desc->device_list);
765         mutex_init(&desc->rlock);
766         mutex_init(&desc->wlock);
767         spin_lock_init(&desc->iuspin);
768         init_waitqueue_head(&desc->wait);
769         desc->wMaxCommand = bufsize;
770         /* this will be expanded and needed in hardware endianness */
771         desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
772         desc->intf = intf;
773         INIT_WORK(&desc->rxwork, wdm_rxwork);
774 
775         rv = -EINVAL;
776         if (!usb_endpoint_is_int_in(ep))
777                 goto err;
778 
779         desc->wMaxPacketSize = usb_endpoint_maxp(ep);
780 
781         desc->orq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
782         if (!desc->orq)
783                 goto err;
784         desc->irq = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
785         if (!desc->irq)
786                 goto err;
787 
788         desc->validity = usb_alloc_urb(0, GFP_KERNEL);
789         if (!desc->validity)
790                 goto err;
791 
792         desc->response = usb_alloc_urb(0, GFP_KERNEL);
793         if (!desc->response)
794                 goto err;
795 
796         desc->command = usb_alloc_urb(0, GFP_KERNEL);
797         if (!desc->command)
798                 goto err;
799 
800         desc->ubuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
801         if (!desc->ubuf)
802                 goto err;
803 
804         desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);
805         if (!desc->sbuf)
806                 goto err;
807 
808         desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);
809         if (!desc->inbuf)
810                 goto err;
811 
812         usb_fill_int_urb(
813                 desc->validity,
814                 interface_to_usbdev(intf),
815                 usb_rcvintpipe(interface_to_usbdev(intf), ep->bEndpointAddress),
816                 desc->sbuf,
817                 desc->wMaxPacketSize,
818                 wdm_int_callback,
819                 desc,
820                 ep->bInterval
821         );
822 
823         desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
824         desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
825         desc->irq->wValue = 0;
826         desc->irq->wIndex = desc->inum; /* already converted */
827         desc->irq->wLength = cpu_to_le16(desc->wMaxCommand);
828 
829         usb_fill_control_urb(
830                 desc->response,
831                 interface_to_usbdev(intf),
832                 /* using common endpoint 0 */
833                 usb_rcvctrlpipe(interface_to_usbdev(desc->intf), 0),
834                 (unsigned char *)desc->irq,
835                 desc->inbuf,
836                 desc->wMaxCommand,
837                 wdm_in_callback,
838                 desc
839         );
840 
841         desc->manage_power = manage_power;
842 
843         spin_lock(&wdm_device_list_lock);
844         list_add(&desc->device_list, &wdm_device_list);
845         spin_unlock(&wdm_device_list_lock);
846 
847         rv = usb_register_dev(intf, &wdm_class);
848         if (rv < 0)
849                 goto err;
850         else
851                 dev_info(&intf->dev, "%s: USB WDM device\n", dev_name(intf->usb_dev));
852 out:
853         return rv;
854 err:
855         spin_lock(&wdm_device_list_lock);
856         list_del(&desc->device_list);
857         spin_unlock(&wdm_device_list_lock);
858         cleanup(desc);
859         return rv;
860 }
861 
862 static int wdm_manage_power(struct usb_interface *intf, int on)
863 {
864         /* need autopm_get/put here to ensure the usbcore sees the new value */
865         int rv = usb_autopm_get_interface(intf);
866 
867         intf->needs_remote_wakeup = on;
868         if (!rv)
869                 usb_autopm_put_interface(intf);
870         return 0;
871 }
872 
873 static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id)
874 {
875         int rv = -EINVAL;
876         struct usb_host_interface *iface;
877         struct usb_endpoint_descriptor *ep;
878         struct usb_cdc_dmm_desc *dmhd;
879         u8 *buffer = intf->altsetting->extra;
880         int buflen = intf->altsetting->extralen;
881         u16 maxcom = WDM_DEFAULT_BUFSIZE;
882 
883         if (!buffer)
884                 goto err;
885         while (buflen > 2) {
886                 if (buffer[1] != USB_DT_CS_INTERFACE) {
887                         dev_err(&intf->dev, "skipping garbage\n");
888                         goto next_desc;
889                 }
890 
891                 switch (buffer[2]) {
892                 case USB_CDC_HEADER_TYPE:
893                         break;
894                 case USB_CDC_DMM_TYPE:
895                         dmhd = (struct usb_cdc_dmm_desc *)buffer;
896                         maxcom = le16_to_cpu(dmhd->wMaxCommand);
897                         dev_dbg(&intf->dev,
898                                 "Finding maximum buffer length: %d", maxcom);
899                         break;
900                 default:
901                         dev_err(&intf->dev,
902                                 "Ignoring extra header, type %d, length %d\n",
903                                 buffer[2], buffer[0]);
904                         break;
905                 }
906 next_desc:
907                 buflen -= buffer[0];
908                 buffer += buffer[0];
909         }
910 
911         iface = intf->cur_altsetting;
912         if (iface->desc.bNumEndpoints != 1)
913                 goto err;
914         ep = &iface->endpoint[0].desc;
915 
916         rv = wdm_create(intf, ep, maxcom, &wdm_manage_power);
917 
918 err:
919         return rv;
920 }
921 
922 /**
923  * usb_cdc_wdm_register - register a WDM subdriver
924  * @intf: usb interface the subdriver will associate with
925  * @ep: interrupt endpoint to monitor for notifications
926  * @bufsize: maximum message size to support for read/write
927  *
928  * Create WDM usb class character device and associate it with intf
929  * without binding, allowing another driver to manage the interface.
930  *
931  * The subdriver will manage the given interrupt endpoint exclusively
932  * and will issue control requests referring to the given intf. It
933  * will otherwise avoid interferring, and in particular not do
934  * usb_set_intfdata/usb_get_intfdata on intf.
935  *
936  * The return value is a pointer to the subdriver's struct usb_driver.
937  * The registering driver is responsible for calling this subdriver's
938  * disconnect, suspend, resume, pre_reset and post_reset methods from
939  * its own.
940  */
941 struct usb_driver *usb_cdc_wdm_register(struct usb_interface *intf,
942                                         struct usb_endpoint_descriptor *ep,
943                                         int bufsize,
944                                         int (*manage_power)(struct usb_interface *, int))
945 {
946         int rv = -EINVAL;
947 
948         rv = wdm_create(intf, ep, bufsize, manage_power);
949         if (rv < 0)
950                 goto err;
951 
952         return &wdm_driver;
953 err:
954         return ERR_PTR(rv);
955 }
956 EXPORT_SYMBOL(usb_cdc_wdm_register);
957 
958 static void wdm_disconnect(struct usb_interface *intf)
959 {
960         struct wdm_device *desc;
961         unsigned long flags;
962 
963         usb_deregister_dev(intf, &wdm_class);
964         desc = wdm_find_device(intf);
965         mutex_lock(&wdm_mutex);
966 
967         /* the spinlock makes sure no new urbs are generated in the callbacks */
968         spin_lock_irqsave(&desc->iuspin, flags);
969         set_bit(WDM_DISCONNECTING, &desc->flags);
970         set_bit(WDM_READ, &desc->flags);
971         /* to terminate pending flushes */
972         clear_bit(WDM_IN_USE, &desc->flags);
973         spin_unlock_irqrestore(&desc->iuspin, flags);
974         wake_up_all(&desc->wait);
975         mutex_lock(&desc->rlock);
976         mutex_lock(&desc->wlock);
977         kill_urbs(desc);
978         cancel_work_sync(&desc->rxwork);
979         mutex_unlock(&desc->wlock);
980         mutex_unlock(&desc->rlock);
981 
982         /* the desc->intf pointer used as list key is now invalid */
983         spin_lock(&wdm_device_list_lock);
984         list_del(&desc->device_list);
985         spin_unlock(&wdm_device_list_lock);
986 
987         if (!desc->count)
988                 cleanup(desc);
989         else
990                 dev_dbg(&intf->dev, "%s: %d open files - postponing cleanup\n", __func__, desc->count);
991         mutex_unlock(&wdm_mutex);
992 }
993 
994 #ifdef CONFIG_PM
995 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
996 {
997         struct wdm_device *desc = wdm_find_device(intf);
998         int rv = 0;
999 
1000         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
1001 
1002         /* if this is an autosuspend the caller does the locking */
1003         if (!PMSG_IS_AUTO(message)) {
1004                 mutex_lock(&desc->rlock);
1005                 mutex_lock(&desc->wlock);
1006         }
1007         spin_lock_irq(&desc->iuspin);
1008 
1009         if (PMSG_IS_AUTO(message) &&
1010                         (test_bit(WDM_IN_USE, &desc->flags)
1011                         || test_bit(WDM_RESPONDING, &desc->flags))) {
1012                 spin_unlock_irq(&desc->iuspin);
1013                 rv = -EBUSY;
1014         } else {
1015 
1016                 set_bit(WDM_SUSPENDING, &desc->flags);
1017                 spin_unlock_irq(&desc->iuspin);
1018                 /* callback submits work - order is essential */
1019                 kill_urbs(desc);
1020                 cancel_work_sync(&desc->rxwork);
1021         }
1022         if (!PMSG_IS_AUTO(message)) {
1023                 mutex_unlock(&desc->wlock);
1024                 mutex_unlock(&desc->rlock);
1025         }
1026 
1027         return rv;
1028 }
1029 #endif
1030 
1031 static int recover_from_urb_loss(struct wdm_device *desc)
1032 {
1033         int rv = 0;
1034 
1035         if (desc->count) {
1036                 rv = usb_submit_urb(desc->validity, GFP_NOIO);
1037                 if (rv < 0)
1038                         dev_err(&desc->intf->dev,
1039                                 "Error resume submitting int urb - %d\n", rv);
1040         }
1041         return rv;
1042 }
1043 
1044 #ifdef CONFIG_PM
1045 static int wdm_resume(struct usb_interface *intf)
1046 {
1047         struct wdm_device *desc = wdm_find_device(intf);
1048         int rv;
1049 
1050         dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
1051 
1052         clear_bit(WDM_SUSPENDING, &desc->flags);
1053         rv = recover_from_urb_loss(desc);
1054 
1055         return rv;
1056 }
1057 #endif
1058 
1059 static int wdm_pre_reset(struct usb_interface *intf)
1060 {
1061         struct wdm_device *desc = wdm_find_device(intf);
1062 
1063         /*
1064          * we notify everybody using poll of
1065          * an exceptional situation
1066          * must be done before recovery lest a spontaneous
1067          * message from the device is lost
1068          */
1069         spin_lock_irq(&desc->iuspin);
1070         set_bit(WDM_RESETTING, &desc->flags);   /* inform read/write */
1071         set_bit(WDM_READ, &desc->flags);        /* unblock read */
1072         clear_bit(WDM_IN_USE, &desc->flags);    /* unblock write */
1073         desc->rerr = -EINTR;
1074         spin_unlock_irq(&desc->iuspin);
1075         wake_up_all(&desc->wait);
1076         mutex_lock(&desc->rlock);
1077         mutex_lock(&desc->wlock);
1078         kill_urbs(desc);
1079         cancel_work_sync(&desc->rxwork);
1080         return 0;
1081 }
1082 
1083 static int wdm_post_reset(struct usb_interface *intf)
1084 {
1085         struct wdm_device *desc = wdm_find_device(intf);
1086         int rv;
1087 
1088         clear_bit(WDM_OVERFLOW, &desc->flags);
1089         clear_bit(WDM_RESETTING, &desc->flags);
1090         rv = recover_from_urb_loss(desc);
1091         mutex_unlock(&desc->wlock);
1092         mutex_unlock(&desc->rlock);
1093         return 0;
1094 }
1095 
1096 static struct usb_driver wdm_driver = {
1097         .name =         "cdc_wdm",
1098         .probe =        wdm_probe,
1099         .disconnect =   wdm_disconnect,
1100 #ifdef CONFIG_PM
1101         .suspend =      wdm_suspend,
1102         .resume =       wdm_resume,
1103         .reset_resume = wdm_resume,
1104 #endif
1105         .pre_reset =    wdm_pre_reset,
1106         .post_reset =   wdm_post_reset,
1107         .id_table =     wdm_ids,
1108         .supports_autosuspend = 1,
1109         .disable_hub_initiated_lpm = 1,
1110 };
1111 
1112 module_usb_driver(wdm_driver);
1113 
1114 MODULE_AUTHOR(DRIVER_AUTHOR);
1115 MODULE_DESCRIPTION(DRIVER_DESC);
1116 MODULE_LICENSE("GPL");
1117 

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