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Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
[karo-tx-linux.git] / drivers / usb / usb-skeleton.c
1 /*
2  * USB Skeleton driver - 2.2
3  *
4  * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
5  *
6  *      This program is free software; you can redistribute it and/or
7  *      modify it under the terms of the GNU General Public License as
8  *      published by the Free Software Foundation, version 2.
9  *
10  * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
11  * but has been rewritten to be easier to read and use.
12  *
13  */
14
15 #include <linux/kernel.h>
16 #include <linux/errno.h>
17 #include <linux/slab.h>
18 #include <linux/module.h>
19 #include <linux/kref.h>
20 #include <linux/uaccess.h>
21 #include <linux/usb.h>
22 #include <linux/mutex.h>
23
24
25 /* Define these values to match your devices */
26 #define USB_SKEL_VENDOR_ID      0xfff0
27 #define USB_SKEL_PRODUCT_ID     0xfff0
28
29 /* table of devices that work with this driver */
30 static const struct usb_device_id skel_table[] = {
31         { USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
32         { }                                     /* Terminating entry */
33 };
34 MODULE_DEVICE_TABLE(usb, skel_table);
35
36
37 /* Get a minor range for your devices from the usb maintainer */
38 #define USB_SKEL_MINOR_BASE     192
39
40 /* our private defines. if this grows any larger, use your own .h file */
41 #define MAX_TRANSFER            (PAGE_SIZE - 512)
42 /* MAX_TRANSFER is chosen so that the VM is not stressed by
43    allocations > PAGE_SIZE and the number of packets in a page
44    is an integer 512 is the largest possible packet on EHCI */
45 #define WRITES_IN_FLIGHT        8
46 /* arbitrarily chosen */
47
48 /* Structure to hold all of our device specific stuff */
49 struct usb_skel {
50         struct usb_device       *udev;                  /* the usb device for this device */
51         struct usb_interface    *interface;             /* the interface for this device */
52         struct semaphore        limit_sem;              /* limiting the number of writes in progress */
53         struct usb_anchor       submitted;              /* in case we need to retract our submissions */
54         struct urb              *bulk_in_urb;           /* the urb to read data with */
55         unsigned char           *bulk_in_buffer;        /* the buffer to receive data */
56         size_t                  bulk_in_size;           /* the size of the receive buffer */
57         size_t                  bulk_in_filled;         /* number of bytes in the buffer */
58         size_t                  bulk_in_copied;         /* already copied to user space */
59         __u8                    bulk_in_endpointAddr;   /* the address of the bulk in endpoint */
60         __u8                    bulk_out_endpointAddr;  /* the address of the bulk out endpoint */
61         int                     errors;                 /* the last request tanked */
62         bool                    ongoing_read;           /* a read is going on */
63         spinlock_t              err_lock;               /* lock for errors */
64         struct kref             kref;
65         struct mutex            io_mutex;               /* synchronize I/O with disconnect */
66         wait_queue_head_t       bulk_in_wait;           /* to wait for an ongoing read */
67 };
68 #define to_skel_dev(d) container_of(d, struct usb_skel, kref)
69
70 static struct usb_driver skel_driver;
71 static void skel_draw_down(struct usb_skel *dev);
72
73 static void skel_delete(struct kref *kref)
74 {
75         struct usb_skel *dev = to_skel_dev(kref);
76
77         usb_free_urb(dev->bulk_in_urb);
78         usb_put_dev(dev->udev);
79         kfree(dev->bulk_in_buffer);
80         kfree(dev);
81 }
82
83 static int skel_open(struct inode *inode, struct file *file)
84 {
85         struct usb_skel *dev;
86         struct usb_interface *interface;
87         int subminor;
88         int retval = 0;
89
90         subminor = iminor(inode);
91
92         interface = usb_find_interface(&skel_driver, subminor);
93         if (!interface) {
94                 pr_err("%s - error, can't find device for minor %d\n",
95                         __func__, subminor);
96                 retval = -ENODEV;
97                 goto exit;
98         }
99
100         dev = usb_get_intfdata(interface);
101         if (!dev) {
102                 retval = -ENODEV;
103                 goto exit;
104         }
105
106         retval = usb_autopm_get_interface(interface);
107         if (retval)
108                 goto exit;
109
110         /* increment our usage count for the device */
111         kref_get(&dev->kref);
112
113         /* save our object in the file's private structure */
114         file->private_data = dev;
115
116 exit:
117         return retval;
118 }
119
120 static int skel_release(struct inode *inode, struct file *file)
121 {
122         struct usb_skel *dev;
123
124         dev = file->private_data;
125         if (dev == NULL)
126                 return -ENODEV;
127
128         /* allow the device to be autosuspended */
129         mutex_lock(&dev->io_mutex);
130         if (dev->interface)
131                 usb_autopm_put_interface(dev->interface);
132         mutex_unlock(&dev->io_mutex);
133
134         /* decrement the count on our device */
135         kref_put(&dev->kref, skel_delete);
136         return 0;
137 }
138
139 static int skel_flush(struct file *file, fl_owner_t id)
140 {
141         struct usb_skel *dev;
142         int res;
143
144         dev = file->private_data;
145         if (dev == NULL)
146                 return -ENODEV;
147
148         /* wait for io to stop */
149         mutex_lock(&dev->io_mutex);
150         skel_draw_down(dev);
151
152         /* read out errors, leave subsequent opens a clean slate */
153         spin_lock_irq(&dev->err_lock);
154         res = dev->errors ? (dev->errors == -EPIPE ? -EPIPE : -EIO) : 0;
155         dev->errors = 0;
156         spin_unlock_irq(&dev->err_lock);
157
158         mutex_unlock(&dev->io_mutex);
159
160         return res;
161 }
162
163 static void skel_read_bulk_callback(struct urb *urb)
164 {
165         struct usb_skel *dev;
166
167         dev = urb->context;
168
169         spin_lock(&dev->err_lock);
170         /* sync/async unlink faults aren't errors */
171         if (urb->status) {
172                 if (!(urb->status == -ENOENT ||
173                     urb->status == -ECONNRESET ||
174                     urb->status == -ESHUTDOWN))
175                         dev_err(&dev->interface->dev,
176                                 "%s - nonzero write bulk status received: %d\n",
177                                 __func__, urb->status);
178
179                 dev->errors = urb->status;
180         } else {
181                 dev->bulk_in_filled = urb->actual_length;
182         }
183         dev->ongoing_read = 0;
184         spin_unlock(&dev->err_lock);
185
186         wake_up_interruptible(&dev->bulk_in_wait);
187 }
188
189 static int skel_do_read_io(struct usb_skel *dev, size_t count)
190 {
191         int rv;
192
193         /* prepare a read */
194         usb_fill_bulk_urb(dev->bulk_in_urb,
195                         dev->udev,
196                         usb_rcvbulkpipe(dev->udev,
197                                 dev->bulk_in_endpointAddr),
198                         dev->bulk_in_buffer,
199                         min(dev->bulk_in_size, count),
200                         skel_read_bulk_callback,
201                         dev);
202         /* tell everybody to leave the URB alone */
203         spin_lock_irq(&dev->err_lock);
204         dev->ongoing_read = 1;
205         spin_unlock_irq(&dev->err_lock);
206
207         /* submit bulk in urb, which means no data to deliver */
208         dev->bulk_in_filled = 0;
209         dev->bulk_in_copied = 0;
210
211         /* do it */
212         rv = usb_submit_urb(dev->bulk_in_urb, GFP_KERNEL);
213         if (rv < 0) {
214                 dev_err(&dev->interface->dev,
215                         "%s - failed submitting read urb, error %d\n",
216                         __func__, rv);
217                 rv = (rv == -ENOMEM) ? rv : -EIO;
218                 spin_lock_irq(&dev->err_lock);
219                 dev->ongoing_read = 0;
220                 spin_unlock_irq(&dev->err_lock);
221         }
222
223         return rv;
224 }
225
226 static ssize_t skel_read(struct file *file, char *buffer, size_t count,
227                          loff_t *ppos)
228 {
229         struct usb_skel *dev;
230         int rv;
231         bool ongoing_io;
232
233         dev = file->private_data;
234
235         /* if we cannot read at all, return EOF */
236         if (!dev->bulk_in_urb || !count)
237                 return 0;
238
239         /* no concurrent readers */
240         rv = mutex_lock_interruptible(&dev->io_mutex);
241         if (rv < 0)
242                 return rv;
243
244         if (!dev->interface) {          /* disconnect() was called */
245                 rv = -ENODEV;
246                 goto exit;
247         }
248
249         /* if IO is under way, we must not touch things */
250 retry:
251         spin_lock_irq(&dev->err_lock);
252         ongoing_io = dev->ongoing_read;
253         spin_unlock_irq(&dev->err_lock);
254
255         if (ongoing_io) {
256                 /* nonblocking IO shall not wait */
257                 if (file->f_flags & O_NONBLOCK) {
258                         rv = -EAGAIN;
259                         goto exit;
260                 }
261                 /*
262                  * IO may take forever
263                  * hence wait in an interruptible state
264                  */
265                 rv = wait_event_interruptible(dev->bulk_in_wait, (!dev->ongoing_read));
266                 if (rv < 0)
267                         goto exit;
268         }
269
270         /* errors must be reported */
271         rv = dev->errors;
272         if (rv < 0) {
273                 /* any error is reported once */
274                 dev->errors = 0;
275                 /* to preserve notifications about reset */
276                 rv = (rv == -EPIPE) ? rv : -EIO;
277                 /* report it */
278                 goto exit;
279         }
280
281         /*
282          * if the buffer is filled we may satisfy the read
283          * else we need to start IO
284          */
285
286         if (dev->bulk_in_filled) {
287                 /* we had read data */
288                 size_t available = dev->bulk_in_filled - dev->bulk_in_copied;
289                 size_t chunk = min(available, count);
290
291                 if (!available) {
292                         /*
293                          * all data has been used
294                          * actual IO needs to be done
295                          */
296                         rv = skel_do_read_io(dev, count);
297                         if (rv < 0)
298                                 goto exit;
299                         else
300                                 goto retry;
301                 }
302                 /*
303                  * data is available
304                  * chunk tells us how much shall be copied
305                  */
306
307                 if (copy_to_user(buffer,
308                                  dev->bulk_in_buffer + dev->bulk_in_copied,
309                                  chunk))
310                         rv = -EFAULT;
311                 else
312                         rv = chunk;
313
314                 dev->bulk_in_copied += chunk;
315
316                 /*
317                  * if we are asked for more than we have,
318                  * we start IO but don't wait
319                  */
320                 if (available < count)
321                         skel_do_read_io(dev, count - chunk);
322         } else {
323                 /* no data in the buffer */
324                 rv = skel_do_read_io(dev, count);
325                 if (rv < 0)
326                         goto exit;
327                 else
328                         goto retry;
329         }
330 exit:
331         mutex_unlock(&dev->io_mutex);
332         return rv;
333 }
334
335 static void skel_write_bulk_callback(struct urb *urb)
336 {
337         struct usb_skel *dev;
338
339         dev = urb->context;
340
341         /* sync/async unlink faults aren't errors */
342         if (urb->status) {
343                 if (!(urb->status == -ENOENT ||
344                     urb->status == -ECONNRESET ||
345                     urb->status == -ESHUTDOWN))
346                         dev_err(&dev->interface->dev,
347                                 "%s - nonzero write bulk status received: %d\n",
348                                 __func__, urb->status);
349
350                 spin_lock(&dev->err_lock);
351                 dev->errors = urb->status;
352                 spin_unlock(&dev->err_lock);
353         }
354
355         /* free up our allocated buffer */
356         usb_free_coherent(urb->dev, urb->transfer_buffer_length,
357                           urb->transfer_buffer, urb->transfer_dma);
358         up(&dev->limit_sem);
359 }
360
361 static ssize_t skel_write(struct file *file, const char *user_buffer,
362                           size_t count, loff_t *ppos)
363 {
364         struct usb_skel *dev;
365         int retval = 0;
366         struct urb *urb = NULL;
367         char *buf = NULL;
368         size_t writesize = min(count, (size_t)MAX_TRANSFER);
369
370         dev = file->private_data;
371
372         /* verify that we actually have some data to write */
373         if (count == 0)
374                 goto exit;
375
376         /*
377          * limit the number of URBs in flight to stop a user from using up all
378          * RAM
379          */
380         if (!(file->f_flags & O_NONBLOCK)) {
381                 if (down_interruptible(&dev->limit_sem)) {
382                         retval = -ERESTARTSYS;
383                         goto exit;
384                 }
385         } else {
386                 if (down_trylock(&dev->limit_sem)) {
387                         retval = -EAGAIN;
388                         goto exit;
389                 }
390         }
391
392         spin_lock_irq(&dev->err_lock);
393         retval = dev->errors;
394         if (retval < 0) {
395                 /* any error is reported once */
396                 dev->errors = 0;
397                 /* to preserve notifications about reset */
398                 retval = (retval == -EPIPE) ? retval : -EIO;
399         }
400         spin_unlock_irq(&dev->err_lock);
401         if (retval < 0)
402                 goto error;
403
404         /* create a urb, and a buffer for it, and copy the data to the urb */
405         urb = usb_alloc_urb(0, GFP_KERNEL);
406         if (!urb) {
407                 retval = -ENOMEM;
408                 goto error;
409         }
410
411         buf = usb_alloc_coherent(dev->udev, writesize, GFP_KERNEL,
412                                  &urb->transfer_dma);
413         if (!buf) {
414                 retval = -ENOMEM;
415                 goto error;
416         }
417
418         if (copy_from_user(buf, user_buffer, writesize)) {
419                 retval = -EFAULT;
420                 goto error;
421         }
422
423         /* this lock makes sure we don't submit URBs to gone devices */
424         mutex_lock(&dev->io_mutex);
425         if (!dev->interface) {          /* disconnect() was called */
426                 mutex_unlock(&dev->io_mutex);
427                 retval = -ENODEV;
428                 goto error;
429         }
430
431         /* initialize the urb properly */
432         usb_fill_bulk_urb(urb, dev->udev,
433                           usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
434                           buf, writesize, skel_write_bulk_callback, dev);
435         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
436         usb_anchor_urb(urb, &dev->submitted);
437
438         /* send the data out the bulk port */
439         retval = usb_submit_urb(urb, GFP_KERNEL);
440         mutex_unlock(&dev->io_mutex);
441         if (retval) {
442                 dev_err(&dev->interface->dev,
443                         "%s - failed submitting write urb, error %d\n",
444                         __func__, retval);
445                 goto error_unanchor;
446         }
447
448         /*
449          * release our reference to this urb, the USB core will eventually free
450          * it entirely
451          */
452         usb_free_urb(urb);
453
454
455         return writesize;
456
457 error_unanchor:
458         usb_unanchor_urb(urb);
459 error:
460         if (urb) {
461                 usb_free_coherent(dev->udev, writesize, buf, urb->transfer_dma);
462                 usb_free_urb(urb);
463         }
464         up(&dev->limit_sem);
465
466 exit:
467         return retval;
468 }
469
470 static const struct file_operations skel_fops = {
471         .owner =        THIS_MODULE,
472         .read =         skel_read,
473         .write =        skel_write,
474         .open =         skel_open,
475         .release =      skel_release,
476         .flush =        skel_flush,
477         .llseek =       noop_llseek,
478 };
479
480 /*
481  * usb class driver info in order to get a minor number from the usb core,
482  * and to have the device registered with the driver core
483  */
484 static struct usb_class_driver skel_class = {
485         .name =         "skel%d",
486         .fops =         &skel_fops,
487         .minor_base =   USB_SKEL_MINOR_BASE,
488 };
489
490 static int skel_probe(struct usb_interface *interface,
491                       const struct usb_device_id *id)
492 {
493         struct usb_skel *dev;
494         struct usb_endpoint_descriptor *bulk_in, *bulk_out;
495         int retval;
496
497         /* allocate memory for our device state and initialize it */
498         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
499         if (!dev)
500                 return -ENOMEM;
501
502         kref_init(&dev->kref);
503         sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
504         mutex_init(&dev->io_mutex);
505         spin_lock_init(&dev->err_lock);
506         init_usb_anchor(&dev->submitted);
507         init_waitqueue_head(&dev->bulk_in_wait);
508
509         dev->udev = usb_get_dev(interface_to_usbdev(interface));
510         dev->interface = interface;
511
512         /* set up the endpoint information */
513         /* use only the first bulk-in and bulk-out endpoints */
514         retval = usb_find_common_endpoints(interface->cur_altsetting,
515                         &bulk_in, &bulk_out, NULL, NULL);
516         if (retval) {
517                 dev_err(&interface->dev,
518                         "Could not find both bulk-in and bulk-out endpoints\n");
519                 goto error;
520         }
521
522         dev->bulk_in_size = usb_endpoint_maxp(bulk_in);
523         dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress;
524         dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL);
525         if (!dev->bulk_in_buffer) {
526                 retval = -ENOMEM;
527                 goto error;
528         }
529         dev->bulk_in_urb = usb_alloc_urb(0, GFP_KERNEL);
530         if (!dev->bulk_in_urb) {
531                 retval = -ENOMEM;
532                 goto error;
533         }
534
535         dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress;
536
537         /* save our data pointer in this interface device */
538         usb_set_intfdata(interface, dev);
539
540         /* we can register the device now, as it is ready */
541         retval = usb_register_dev(interface, &skel_class);
542         if (retval) {
543                 /* something prevented us from registering this driver */
544                 dev_err(&interface->dev,
545                         "Not able to get a minor for this device.\n");
546                 usb_set_intfdata(interface, NULL);
547                 goto error;
548         }
549
550         /* let the user know what node this device is now attached to */
551         dev_info(&interface->dev,
552                  "USB Skeleton device now attached to USBSkel-%d",
553                  interface->minor);
554         return 0;
555
556 error:
557         /* this frees allocated memory */
558         kref_put(&dev->kref, skel_delete);
559
560         return retval;
561 }
562
563 static void skel_disconnect(struct usb_interface *interface)
564 {
565         struct usb_skel *dev;
566         int minor = interface->minor;
567
568         dev = usb_get_intfdata(interface);
569         usb_set_intfdata(interface, NULL);
570
571         /* give back our minor */
572         usb_deregister_dev(interface, &skel_class);
573
574         /* prevent more I/O from starting */
575         mutex_lock(&dev->io_mutex);
576         dev->interface = NULL;
577         mutex_unlock(&dev->io_mutex);
578
579         usb_kill_anchored_urbs(&dev->submitted);
580
581         /* decrement our usage count */
582         kref_put(&dev->kref, skel_delete);
583
584         dev_info(&interface->dev, "USB Skeleton #%d now disconnected", minor);
585 }
586
587 static void skel_draw_down(struct usb_skel *dev)
588 {
589         int time;
590
591         time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
592         if (!time)
593                 usb_kill_anchored_urbs(&dev->submitted);
594         usb_kill_urb(dev->bulk_in_urb);
595 }
596
597 static int skel_suspend(struct usb_interface *intf, pm_message_t message)
598 {
599         struct usb_skel *dev = usb_get_intfdata(intf);
600
601         if (!dev)
602                 return 0;
603         skel_draw_down(dev);
604         return 0;
605 }
606
607 static int skel_resume(struct usb_interface *intf)
608 {
609         return 0;
610 }
611
612 static int skel_pre_reset(struct usb_interface *intf)
613 {
614         struct usb_skel *dev = usb_get_intfdata(intf);
615
616         mutex_lock(&dev->io_mutex);
617         skel_draw_down(dev);
618
619         return 0;
620 }
621
622 static int skel_post_reset(struct usb_interface *intf)
623 {
624         struct usb_skel *dev = usb_get_intfdata(intf);
625
626         /* we are sure no URBs are active - no locking needed */
627         dev->errors = -EPIPE;
628         mutex_unlock(&dev->io_mutex);
629
630         return 0;
631 }
632
633 static struct usb_driver skel_driver = {
634         .name =         "skeleton",
635         .probe =        skel_probe,
636         .disconnect =   skel_disconnect,
637         .suspend =      skel_suspend,
638         .resume =       skel_resume,
639         .pre_reset =    skel_pre_reset,
640         .post_reset =   skel_post_reset,
641         .id_table =     skel_table,
642         .supports_autosuspend = 1,
643 };
644
645 module_usb_driver(skel_driver);
646
647 MODULE_LICENSE("GPL");