Version:  2.0.40 2.2.26 2.4.37 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16

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

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us