Merge git://github.com/herbertx/crypto
[pandora-kernel.git] / drivers / usb / misc / ldusb.c
1 /**
2  * Generic USB driver for report based interrupt in/out devices
3  * like LD Didactic's USB devices. LD Didactic's USB devices are
4  * HID devices which do not use HID report definitons (they use
5  * raw interrupt in and our reports only for communication).
6  *
7  * This driver uses a ring buffer for time critical reading of
8  * interrupt in reports and provides read and write methods for
9  * raw interrupt reports (similar to the Windows HID driver).
10  * Devices based on the book USB COMPLETE by Jan Axelson may need
11  * such a compatibility to the Windows HID driver.
12  *
13  * Copyright (C) 2005 Michael Hund <mhund@ld-didactic.de>
14  *
15  *      This program is free software; you can redistribute it and/or
16  *      modify it under the terms of the GNU General Public License as
17  *      published by the Free Software Foundation; either version 2 of
18  *      the License, or (at your option) any later version.
19  *
20  * Derived from Lego USB Tower driver
21  * Copyright (C) 2003 David Glance <advidgsf@sourceforge.net>
22  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
23  */
24
25 #include <linux/kernel.h>
26 #include <linux/errno.h>
27 #include <linux/init.h>
28 #include <linux/slab.h>
29 #include <linux/module.h>
30 #include <linux/mutex.h>
31
32 #include <asm/uaccess.h>
33 #include <linux/input.h>
34 #include <linux/usb.h>
35 #include <linux/poll.h>
36
37 /* Define these values to match your devices */
38 #define USB_VENDOR_ID_LD                0x0f11  /* USB Vendor ID of LD Didactic GmbH */
39 #define USB_DEVICE_ID_LD_CASSY          0x1000  /* USB Product ID of CASSY-S modules with 8 bytes endpoint size */
40 #define USB_DEVICE_ID_LD_CASSY2         0x1001  /* USB Product ID of CASSY-S modules with 64 bytes endpoint size */
41 #define USB_DEVICE_ID_LD_POCKETCASSY    0x1010  /* USB Product ID of Pocket-CASSY */
42 #define USB_DEVICE_ID_LD_POCKETCASSY2   0x1011  /* USB Product ID of Pocket-CASSY 2 (reserved) */
43 #define USB_DEVICE_ID_LD_MOBILECASSY    0x1020  /* USB Product ID of Mobile-CASSY */
44 #define USB_DEVICE_ID_LD_MOBILECASSY2   0x1021  /* USB Product ID of Mobile-CASSY 2 (reserved) */
45 #define USB_DEVICE_ID_LD_MICROCASSYVOLTAGE      0x1031  /* USB Product ID of Micro-CASSY Voltage */
46 #define USB_DEVICE_ID_LD_MICROCASSYCURRENT      0x1032  /* USB Product ID of Micro-CASSY Current */
47 #define USB_DEVICE_ID_LD_MICROCASSYTIME         0x1033  /* USB Product ID of Micro-CASSY Time (reserved) */
48 #define USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE  0x1035  /* USB Product ID of Micro-CASSY Temperature */
49 #define USB_DEVICE_ID_LD_MICROCASSYPH           0x1038  /* USB Product ID of Micro-CASSY pH */
50 #define USB_DEVICE_ID_LD_JWM            0x1080  /* USB Product ID of Joule and Wattmeter */
51 #define USB_DEVICE_ID_LD_DMMP           0x1081  /* USB Product ID of Digital Multimeter P (reserved) */
52 #define USB_DEVICE_ID_LD_UMIP           0x1090  /* USB Product ID of UMI P */
53 #define USB_DEVICE_ID_LD_UMIC           0x10A0  /* USB Product ID of UMI C */
54 #define USB_DEVICE_ID_LD_UMIB           0x10B0  /* USB Product ID of UMI B */
55 #define USB_DEVICE_ID_LD_XRAY           0x1100  /* USB Product ID of X-Ray Apparatus 55481 */
56 #define USB_DEVICE_ID_LD_XRAY2          0x1101  /* USB Product ID of X-Ray Apparatus 554800 */
57 #define USB_DEVICE_ID_LD_XRAYCT         0x1110  /* USB Product ID of X-Ray Apparatus CT 554821*/
58 #define USB_DEVICE_ID_LD_VIDEOCOM       0x1200  /* USB Product ID of VideoCom */
59 #define USB_DEVICE_ID_LD_MOTOR          0x1210  /* USB Product ID of Motor (reserved) */
60 #define USB_DEVICE_ID_LD_COM3LAB        0x2000  /* USB Product ID of COM3LAB */
61 #define USB_DEVICE_ID_LD_TELEPORT       0x2010  /* USB Product ID of Terminal Adapter */
62 #define USB_DEVICE_ID_LD_NETWORKANALYSER 0x2020 /* USB Product ID of Network Analyser */
63 #define USB_DEVICE_ID_LD_POWERCONTROL   0x2030  /* USB Product ID of Converter Control Unit */
64 #define USB_DEVICE_ID_LD_MACHINETEST    0x2040  /* USB Product ID of Machine Test System */
65 #define USB_DEVICE_ID_LD_MOSTANALYSER   0x2050  /* USB Product ID of MOST Protocol Analyser */
66 #define USB_DEVICE_ID_LD_MOSTANALYSER2  0x2051  /* USB Product ID of MOST Protocol Analyser 2 */
67 #define USB_DEVICE_ID_LD_ABSESP         0x2060  /* USB Product ID of ABS ESP */
68 #define USB_DEVICE_ID_LD_AUTODATABUS    0x2070  /* USB Product ID of Automotive Data Buses */
69 #define USB_DEVICE_ID_LD_MCT            0x2080  /* USB Product ID of Microcontroller technique */
70 #define USB_DEVICE_ID_LD_HYBRID         0x2090  /* USB Product ID of Automotive Hybrid */
71 #define USB_DEVICE_ID_LD_HEATCONTROL    0x20A0  /* USB Product ID of Heat control */
72
73 #define USB_VENDOR_ID_VERNIER           0x08f7
74 #define USB_DEVICE_ID_VERNIER_GOTEMP    0x0002
75 #define USB_DEVICE_ID_VERNIER_SKIP      0x0003
76 #define USB_DEVICE_ID_VERNIER_CYCLOPS   0x0004
77 #define USB_DEVICE_ID_VERNIER_LCSPEC    0x0006
78
79 #ifdef CONFIG_USB_DYNAMIC_MINORS
80 #define USB_LD_MINOR_BASE       0
81 #else
82 #define USB_LD_MINOR_BASE       176
83 #endif
84
85 /* table of devices that work with this driver */
86 static const struct usb_device_id ld_usb_table[] = {
87         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY) },
88         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_CASSY2) },
89         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY) },
90         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POCKETCASSY2) },
91         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY) },
92         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOBILECASSY2) },
93         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYVOLTAGE) },
94         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYCURRENT) },
95         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTIME) },
96         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYTEMPERATURE) },
97         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MICROCASSYPH) },
98         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_JWM) },
99         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_DMMP) },
100         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIP) },
101         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIC) },
102         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_UMIB) },
103         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY) },
104         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_XRAY2) },
105         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_VIDEOCOM) },
106         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOTOR) },
107         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_COM3LAB) },
108         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_TELEPORT) },
109         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_NETWORKANALYSER) },
110         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_POWERCONTROL) },
111         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MACHINETEST) },
112         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER) },
113         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MOSTANALYSER2) },
114         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_ABSESP) },
115         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_AUTODATABUS) },
116         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_MCT) },
117         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HYBRID) },
118         { USB_DEVICE(USB_VENDOR_ID_LD, USB_DEVICE_ID_LD_HEATCONTROL) },
119         { USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_GOTEMP) },
120         { USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_SKIP) },
121         { USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_CYCLOPS) },
122         { USB_DEVICE(USB_VENDOR_ID_VERNIER, USB_DEVICE_ID_VERNIER_LCSPEC) },
123         { }                                     /* Terminating entry */
124 };
125 MODULE_DEVICE_TABLE(usb, ld_usb_table);
126 MODULE_VERSION("V0.14");
127 MODULE_AUTHOR("Michael Hund <mhund@ld-didactic.de>");
128 MODULE_DESCRIPTION("LD USB Driver");
129 MODULE_LICENSE("GPL");
130 MODULE_SUPPORTED_DEVICE("LD USB Devices");
131
132 #ifdef CONFIG_USB_DEBUG
133         static int debug = 1;
134 #else
135         static int debug = 0;
136 #endif
137
138 /* Use our own dbg macro */
139 #define dbg_info(dev, format, arg...) do { if (debug) dev_info(dev , format , ## arg); } while (0)
140
141 /* Module parameters */
142 module_param(debug, int, S_IRUGO | S_IWUSR);
143 MODULE_PARM_DESC(debug, "Debug enabled or not");
144
145 /* All interrupt in transfers are collected in a ring buffer to
146  * avoid racing conditions and get better performance of the driver.
147  */
148 static int ring_buffer_size = 128;
149 module_param(ring_buffer_size, int, 0);
150 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size in reports");
151
152 /* The write_buffer can contain more than one interrupt out transfer.
153  */
154 static int write_buffer_size = 10;
155 module_param(write_buffer_size, int, 0);
156 MODULE_PARM_DESC(write_buffer_size, "Write buffer size in reports");
157
158 /* As of kernel version 2.6.4 ehci-hcd uses an
159  * "only one interrupt transfer per frame" shortcut
160  * to simplify the scheduling of periodic transfers.
161  * This conflicts with our standard 1ms intervals for in and out URBs.
162  * We use default intervals of 2ms for in and 2ms for out transfers,
163  * which should be fast enough.
164  * Increase the interval to allow more devices that do interrupt transfers,
165  * or set to 1 to use the standard interval from the endpoint descriptors.
166  */
167 static int min_interrupt_in_interval = 2;
168 module_param(min_interrupt_in_interval, int, 0);
169 MODULE_PARM_DESC(min_interrupt_in_interval, "Minimum interrupt in interval in ms");
170
171 static int min_interrupt_out_interval = 2;
172 module_param(min_interrupt_out_interval, int, 0);
173 MODULE_PARM_DESC(min_interrupt_out_interval, "Minimum interrupt out interval in ms");
174
175 /* Structure to hold all of our device specific stuff */
176 struct ld_usb {
177         struct mutex            mutex;          /* locks this structure */
178         struct usb_interface*   intf;           /* save off the usb interface pointer */
179
180         int                     open_count;     /* number of times this port has been opened */
181
182         char*                   ring_buffer;
183         unsigned int            ring_head;
184         unsigned int            ring_tail;
185
186         wait_queue_head_t       read_wait;
187         wait_queue_head_t       write_wait;
188
189         char*                   interrupt_in_buffer;
190         struct usb_endpoint_descriptor* interrupt_in_endpoint;
191         struct urb*             interrupt_in_urb;
192         int                     interrupt_in_interval;
193         size_t                  interrupt_in_endpoint_size;
194         int                     interrupt_in_running;
195         int                     interrupt_in_done;
196         int                     buffer_overflow;
197         spinlock_t              rbsl;
198
199         char*                   interrupt_out_buffer;
200         struct usb_endpoint_descriptor* interrupt_out_endpoint;
201         struct urb*             interrupt_out_urb;
202         int                     interrupt_out_interval;
203         size_t                  interrupt_out_endpoint_size;
204         int                     interrupt_out_busy;
205 };
206
207 static struct usb_driver ld_usb_driver;
208
209 /**
210  *      ld_usb_abort_transfers
211  *      aborts transfers and frees associated data structures
212  */
213 static void ld_usb_abort_transfers(struct ld_usb *dev)
214 {
215         /* shutdown transfer */
216         if (dev->interrupt_in_running) {
217                 dev->interrupt_in_running = 0;
218                 if (dev->intf)
219                         usb_kill_urb(dev->interrupt_in_urb);
220         }
221         if (dev->interrupt_out_busy)
222                 if (dev->intf)
223                         usb_kill_urb(dev->interrupt_out_urb);
224 }
225
226 /**
227  *      ld_usb_delete
228  */
229 static void ld_usb_delete(struct ld_usb *dev)
230 {
231         ld_usb_abort_transfers(dev);
232
233         /* free data structures */
234         usb_free_urb(dev->interrupt_in_urb);
235         usb_free_urb(dev->interrupt_out_urb);
236         kfree(dev->ring_buffer);
237         kfree(dev->interrupt_in_buffer);
238         kfree(dev->interrupt_out_buffer);
239         kfree(dev);
240 }
241
242 /**
243  *      ld_usb_interrupt_in_callback
244  */
245 static void ld_usb_interrupt_in_callback(struct urb *urb)
246 {
247         struct ld_usb *dev = urb->context;
248         size_t *actual_buffer;
249         unsigned int next_ring_head;
250         int status = urb->status;
251         int retval;
252
253         if (status) {
254                 if (status == -ENOENT ||
255                     status == -ECONNRESET ||
256                     status == -ESHUTDOWN) {
257                         goto exit;
258                 } else {
259                         dbg_info(&dev->intf->dev, "%s: nonzero status received: %d\n",
260                                  __func__, status);
261                         spin_lock(&dev->rbsl);
262                         goto resubmit; /* maybe we can recover */
263                 }
264         }
265
266         spin_lock(&dev->rbsl);
267         if (urb->actual_length > 0) {
268                 next_ring_head = (dev->ring_head+1) % ring_buffer_size;
269                 if (next_ring_head != dev->ring_tail) {
270                         actual_buffer = (size_t*)(dev->ring_buffer + dev->ring_head*(sizeof(size_t)+dev->interrupt_in_endpoint_size));
271                         /* actual_buffer gets urb->actual_length + interrupt_in_buffer */
272                         *actual_buffer = urb->actual_length;
273                         memcpy(actual_buffer+1, dev->interrupt_in_buffer, urb->actual_length);
274                         dev->ring_head = next_ring_head;
275                         dbg_info(&dev->intf->dev, "%s: received %d bytes\n",
276                                  __func__, urb->actual_length);
277                 } else {
278                         dev_warn(&dev->intf->dev,
279                                  "Ring buffer overflow, %d bytes dropped\n",
280                                  urb->actual_length);
281                         dev->buffer_overflow = 1;
282                 }
283         }
284
285 resubmit:
286         /* resubmit if we're still running */
287         if (dev->interrupt_in_running && !dev->buffer_overflow && dev->intf) {
288                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
289                 if (retval) {
290                         dev_err(&dev->intf->dev,
291                                 "usb_submit_urb failed (%d)\n", retval);
292                         dev->buffer_overflow = 1;
293                 }
294         }
295         spin_unlock(&dev->rbsl);
296 exit:
297         dev->interrupt_in_done = 1;
298         wake_up_interruptible(&dev->read_wait);
299 }
300
301 /**
302  *      ld_usb_interrupt_out_callback
303  */
304 static void ld_usb_interrupt_out_callback(struct urb *urb)
305 {
306         struct ld_usb *dev = urb->context;
307         int status = urb->status;
308
309         /* sync/async unlink faults aren't errors */
310         if (status && !(status == -ENOENT ||
311                         status == -ECONNRESET ||
312                         status == -ESHUTDOWN))
313                 dbg_info(&dev->intf->dev,
314                          "%s - nonzero write interrupt status received: %d\n",
315                          __func__, status);
316
317         dev->interrupt_out_busy = 0;
318         wake_up_interruptible(&dev->write_wait);
319 }
320
321 /**
322  *      ld_usb_open
323  */
324 static int ld_usb_open(struct inode *inode, struct file *file)
325 {
326         struct ld_usb *dev;
327         int subminor;
328         int retval;
329         struct usb_interface *interface;
330
331         nonseekable_open(inode, file);
332         subminor = iminor(inode);
333
334         interface = usb_find_interface(&ld_usb_driver, subminor);
335
336         if (!interface) {
337                 err("%s - error, can't find device for minor %d\n",
338                      __func__, subminor);
339                 return -ENODEV;
340         }
341
342         dev = usb_get_intfdata(interface);
343
344         if (!dev)
345                 return -ENODEV;
346
347         /* lock this device */
348         if (mutex_lock_interruptible(&dev->mutex))
349                 return -ERESTARTSYS;
350
351         /* allow opening only once */
352         if (dev->open_count) {
353                 retval = -EBUSY;
354                 goto unlock_exit;
355         }
356         dev->open_count = 1;
357
358         /* initialize in direction */
359         dev->ring_head = 0;
360         dev->ring_tail = 0;
361         dev->buffer_overflow = 0;
362         usb_fill_int_urb(dev->interrupt_in_urb,
363                          interface_to_usbdev(interface),
364                          usb_rcvintpipe(interface_to_usbdev(interface),
365                                         dev->interrupt_in_endpoint->bEndpointAddress),
366                          dev->interrupt_in_buffer,
367                          dev->interrupt_in_endpoint_size,
368                          ld_usb_interrupt_in_callback,
369                          dev,
370                          dev->interrupt_in_interval);
371
372         dev->interrupt_in_running = 1;
373         dev->interrupt_in_done = 0;
374
375         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
376         if (retval) {
377                 dev_err(&interface->dev, "Couldn't submit interrupt_in_urb %d\n", retval);
378                 dev->interrupt_in_running = 0;
379                 dev->open_count = 0;
380                 goto unlock_exit;
381         }
382
383         /* save device in the file's private structure */
384         file->private_data = dev;
385
386 unlock_exit:
387         mutex_unlock(&dev->mutex);
388
389         return retval;
390 }
391
392 /**
393  *      ld_usb_release
394  */
395 static int ld_usb_release(struct inode *inode, struct file *file)
396 {
397         struct ld_usb *dev;
398         int retval = 0;
399
400         dev = file->private_data;
401
402         if (dev == NULL) {
403                 retval = -ENODEV;
404                 goto exit;
405         }
406
407         if (mutex_lock_interruptible(&dev->mutex)) {
408                 retval = -ERESTARTSYS;
409                 goto exit;
410         }
411
412         if (dev->open_count != 1) {
413                 retval = -ENODEV;
414                 goto unlock_exit;
415         }
416         if (dev->intf == NULL) {
417                 /* the device was unplugged before the file was released */
418                 mutex_unlock(&dev->mutex);
419                 /* unlock here as ld_usb_delete frees dev */
420                 ld_usb_delete(dev);
421                 goto exit;
422         }
423
424         /* wait until write transfer is finished */
425         if (dev->interrupt_out_busy)
426                 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
427         ld_usb_abort_transfers(dev);
428         dev->open_count = 0;
429
430 unlock_exit:
431         mutex_unlock(&dev->mutex);
432
433 exit:
434         return retval;
435 }
436
437 /**
438  *      ld_usb_poll
439  */
440 static unsigned int ld_usb_poll(struct file *file, poll_table *wait)
441 {
442         struct ld_usb *dev;
443         unsigned int mask = 0;
444
445         dev = file->private_data;
446
447         if (!dev->intf)
448                 return POLLERR | POLLHUP;
449
450         poll_wait(file, &dev->read_wait, wait);
451         poll_wait(file, &dev->write_wait, wait);
452
453         if (dev->ring_head != dev->ring_tail)
454                 mask |= POLLIN | POLLRDNORM;
455         if (!dev->interrupt_out_busy)
456                 mask |= POLLOUT | POLLWRNORM;
457
458         return mask;
459 }
460
461 /**
462  *      ld_usb_read
463  */
464 static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count,
465                            loff_t *ppos)
466 {
467         struct ld_usb *dev;
468         size_t *actual_buffer;
469         size_t bytes_to_read;
470         int retval = 0;
471         int rv;
472
473         dev = file->private_data;
474
475         /* verify that we actually have some data to read */
476         if (count == 0)
477                 goto exit;
478
479         /* lock this object */
480         if (mutex_lock_interruptible(&dev->mutex)) {
481                 retval = -ERESTARTSYS;
482                 goto exit;
483         }
484
485         /* verify that the device wasn't unplugged */
486         if (dev->intf == NULL) {
487                 retval = -ENODEV;
488                 err("No device or device unplugged %d\n", retval);
489                 goto unlock_exit;
490         }
491
492         /* wait for data */
493         spin_lock_irq(&dev->rbsl);
494         if (dev->ring_head == dev->ring_tail) {
495                 dev->interrupt_in_done = 0;
496                 spin_unlock_irq(&dev->rbsl);
497                 if (file->f_flags & O_NONBLOCK) {
498                         retval = -EAGAIN;
499                         goto unlock_exit;
500                 }
501                 retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done);
502                 if (retval < 0)
503                         goto unlock_exit;
504         } else {
505                 spin_unlock_irq(&dev->rbsl);
506         }
507
508         /* actual_buffer contains actual_length + interrupt_in_buffer */
509         actual_buffer = (size_t*)(dev->ring_buffer + dev->ring_tail*(sizeof(size_t)+dev->interrupt_in_endpoint_size));
510         bytes_to_read = min(count, *actual_buffer);
511         if (bytes_to_read < *actual_buffer)
512                 dev_warn(&dev->intf->dev, "Read buffer overflow, %zd bytes dropped\n",
513                          *actual_buffer-bytes_to_read);
514
515         /* copy one interrupt_in_buffer from ring_buffer into userspace */
516         if (copy_to_user(buffer, actual_buffer+1, bytes_to_read)) {
517                 retval = -EFAULT;
518                 goto unlock_exit;
519         }
520         dev->ring_tail = (dev->ring_tail+1) % ring_buffer_size;
521
522         retval = bytes_to_read;
523
524         spin_lock_irq(&dev->rbsl);
525         if (dev->buffer_overflow) {
526                 dev->buffer_overflow = 0;
527                 spin_unlock_irq(&dev->rbsl);
528                 rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
529                 if (rv < 0)
530                         dev->buffer_overflow = 1;
531         } else {
532                 spin_unlock_irq(&dev->rbsl);
533         }
534
535 unlock_exit:
536         /* unlock the device */
537         mutex_unlock(&dev->mutex);
538
539 exit:
540         return retval;
541 }
542
543 /**
544  *      ld_usb_write
545  */
546 static ssize_t ld_usb_write(struct file *file, const char __user *buffer,
547                             size_t count, loff_t *ppos)
548 {
549         struct ld_usb *dev;
550         size_t bytes_to_write;
551         int retval = 0;
552
553         dev = file->private_data;
554
555         /* verify that we actually have some data to write */
556         if (count == 0)
557                 goto exit;
558
559         /* lock this object */
560         if (mutex_lock_interruptible(&dev->mutex)) {
561                 retval = -ERESTARTSYS;
562                 goto exit;
563         }
564
565         /* verify that the device wasn't unplugged */
566         if (dev->intf == NULL) {
567                 retval = -ENODEV;
568                 err("No device or device unplugged %d\n", retval);
569                 goto unlock_exit;
570         }
571
572         /* wait until previous transfer is finished */
573         if (dev->interrupt_out_busy) {
574                 if (file->f_flags & O_NONBLOCK) {
575                         retval = -EAGAIN;
576                         goto unlock_exit;
577                 }
578                 retval = wait_event_interruptible(dev->write_wait, !dev->interrupt_out_busy);
579                 if (retval < 0) {
580                         goto unlock_exit;
581                 }
582         }
583
584         /* write the data into interrupt_out_buffer from userspace */
585         bytes_to_write = min(count, write_buffer_size*dev->interrupt_out_endpoint_size);
586         if (bytes_to_write < count)
587                 dev_warn(&dev->intf->dev, "Write buffer overflow, %zd bytes dropped\n",count-bytes_to_write);
588         dbg_info(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n", __func__, count, bytes_to_write);
589
590         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
591                 retval = -EFAULT;
592                 goto unlock_exit;
593         }
594
595         if (dev->interrupt_out_endpoint == NULL) {
596                 /* try HID_REQ_SET_REPORT=9 on control_endpoint instead of interrupt_out_endpoint */
597                 retval = usb_control_msg(interface_to_usbdev(dev->intf),
598                                          usb_sndctrlpipe(interface_to_usbdev(dev->intf), 0),
599                                          9,
600                                          USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
601                                          1 << 8, 0,
602                                          dev->interrupt_out_buffer,
603                                          bytes_to_write,
604                                          USB_CTRL_SET_TIMEOUT * HZ);
605                 if (retval < 0)
606                         err("Couldn't submit HID_REQ_SET_REPORT %d\n", retval);
607                 goto unlock_exit;
608         }
609
610         /* send off the urb */
611         usb_fill_int_urb(dev->interrupt_out_urb,
612                          interface_to_usbdev(dev->intf),
613                          usb_sndintpipe(interface_to_usbdev(dev->intf),
614                                         dev->interrupt_out_endpoint->bEndpointAddress),
615                          dev->interrupt_out_buffer,
616                          bytes_to_write,
617                          ld_usb_interrupt_out_callback,
618                          dev,
619                          dev->interrupt_out_interval);
620
621         dev->interrupt_out_busy = 1;
622         wmb();
623
624         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
625         if (retval) {
626                 dev->interrupt_out_busy = 0;
627                 err("Couldn't submit interrupt_out_urb %d\n", retval);
628                 goto unlock_exit;
629         }
630         retval = bytes_to_write;
631
632 unlock_exit:
633         /* unlock the device */
634         mutex_unlock(&dev->mutex);
635
636 exit:
637         return retval;
638 }
639
640 /* file operations needed when we register this driver */
641 static const struct file_operations ld_usb_fops = {
642         .owner =        THIS_MODULE,
643         .read  =        ld_usb_read,
644         .write =        ld_usb_write,
645         .open =         ld_usb_open,
646         .release =      ld_usb_release,
647         .poll =         ld_usb_poll,
648         .llseek =       no_llseek,
649 };
650
651 /*
652  * usb class driver info in order to get a minor number from the usb core,
653  * and to have the device registered with the driver core
654  */
655 static struct usb_class_driver ld_usb_class = {
656         .name =         "ldusb%d",
657         .fops =         &ld_usb_fops,
658         .minor_base =   USB_LD_MINOR_BASE,
659 };
660
661 /**
662  *      ld_usb_probe
663  *
664  *      Called by the usb core when a new device is connected that it thinks
665  *      this driver might be interested in.
666  */
667 static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
668 {
669         struct usb_device *udev = interface_to_usbdev(intf);
670         struct ld_usb *dev = NULL;
671         struct usb_host_interface *iface_desc;
672         struct usb_endpoint_descriptor *endpoint;
673         char *buffer;
674         int i;
675         int retval = -ENOMEM;
676
677         /* allocate memory for our device state and initialize it */
678
679         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
680         if (dev == NULL) {
681                 dev_err(&intf->dev, "Out of memory\n");
682                 goto exit;
683         }
684         mutex_init(&dev->mutex);
685         spin_lock_init(&dev->rbsl);
686         dev->intf = intf;
687         init_waitqueue_head(&dev->read_wait);
688         init_waitqueue_head(&dev->write_wait);
689
690         /* workaround for early firmware versions on fast computers */
691         if ((le16_to_cpu(udev->descriptor.idVendor) == USB_VENDOR_ID_LD) &&
692             ((le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_CASSY) ||
693              (le16_to_cpu(udev->descriptor.idProduct) == USB_DEVICE_ID_LD_COM3LAB)) &&
694             (le16_to_cpu(udev->descriptor.bcdDevice) <= 0x103)) {
695                 buffer = kmalloc(256, GFP_KERNEL);
696                 if (buffer == NULL) {
697                         dev_err(&intf->dev, "Couldn't allocate string buffer\n");
698                         goto error;
699                 }
700                 /* usb_string makes SETUP+STALL to leave always ControlReadLoop */
701                 usb_string(udev, 255, buffer, 256);
702                 kfree(buffer);
703         }
704
705         iface_desc = intf->cur_altsetting;
706
707         /* set up the endpoint information */
708         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
709                 endpoint = &iface_desc->endpoint[i].desc;
710
711                 if (usb_endpoint_is_int_in(endpoint))
712                         dev->interrupt_in_endpoint = endpoint;
713
714                 if (usb_endpoint_is_int_out(endpoint))
715                         dev->interrupt_out_endpoint = endpoint;
716         }
717         if (dev->interrupt_in_endpoint == NULL) {
718                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
719                 goto error;
720         }
721         if (dev->interrupt_out_endpoint == NULL)
722                 dev_warn(&intf->dev, "Interrupt out endpoint not found (using control endpoint instead)\n");
723
724         dev->interrupt_in_endpoint_size = usb_endpoint_maxp(dev->interrupt_in_endpoint);
725         dev->ring_buffer = kmalloc(ring_buffer_size*(sizeof(size_t)+dev->interrupt_in_endpoint_size), GFP_KERNEL);
726         if (!dev->ring_buffer) {
727                 dev_err(&intf->dev, "Couldn't allocate ring_buffer\n");
728                 goto error;
729         }
730         dev->interrupt_in_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
731         if (!dev->interrupt_in_buffer) {
732                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_buffer\n");
733                 goto error;
734         }
735         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
736         if (!dev->interrupt_in_urb) {
737                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n");
738                 goto error;
739         }
740         dev->interrupt_out_endpoint_size = dev->interrupt_out_endpoint ? usb_endpoint_maxp(dev->interrupt_out_endpoint) :
741                                                                          udev->descriptor.bMaxPacketSize0;
742         dev->interrupt_out_buffer = kmalloc(write_buffer_size*dev->interrupt_out_endpoint_size, GFP_KERNEL);
743         if (!dev->interrupt_out_buffer) {
744                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_buffer\n");
745                 goto error;
746         }
747         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
748         if (!dev->interrupt_out_urb) {
749                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n");
750                 goto error;
751         }
752         dev->interrupt_in_interval = min_interrupt_in_interval > dev->interrupt_in_endpoint->bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
753         if (dev->interrupt_out_endpoint)
754                 dev->interrupt_out_interval = min_interrupt_out_interval > dev->interrupt_out_endpoint->bInterval ? min_interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
755
756         /* we can register the device now, as it is ready */
757         usb_set_intfdata(intf, dev);
758
759         retval = usb_register_dev(intf, &ld_usb_class);
760         if (retval) {
761                 /* something prevented us from registering this driver */
762                 dev_err(&intf->dev, "Not able to get a minor for this device.\n");
763                 usb_set_intfdata(intf, NULL);
764                 goto error;
765         }
766
767         /* let the user know what node this device is now attached to */
768         dev_info(&intf->dev, "LD USB Device #%d now attached to major %d minor %d\n",
769                 (intf->minor - USB_LD_MINOR_BASE), USB_MAJOR, intf->minor);
770
771 exit:
772         return retval;
773
774 error:
775         ld_usb_delete(dev);
776
777         return retval;
778 }
779
780 /**
781  *      ld_usb_disconnect
782  *
783  *      Called by the usb core when the device is removed from the system.
784  */
785 static void ld_usb_disconnect(struct usb_interface *intf)
786 {
787         struct ld_usb *dev;
788         int minor;
789
790         dev = usb_get_intfdata(intf);
791         usb_set_intfdata(intf, NULL);
792
793         minor = intf->minor;
794
795         /* give back our minor */
796         usb_deregister_dev(intf, &ld_usb_class);
797
798         mutex_lock(&dev->mutex);
799
800         /* if the device is not opened, then we clean up right now */
801         if (!dev->open_count) {
802                 mutex_unlock(&dev->mutex);
803                 ld_usb_delete(dev);
804         } else {
805                 dev->intf = NULL;
806                 /* wake up pollers */
807                 wake_up_interruptible_all(&dev->read_wait);
808                 wake_up_interruptible_all(&dev->write_wait);
809                 mutex_unlock(&dev->mutex);
810         }
811
812         dev_info(&intf->dev, "LD USB Device #%d now disconnected\n",
813                  (minor - USB_LD_MINOR_BASE));
814 }
815
816 /* usb specific object needed to register this driver with the usb subsystem */
817 static struct usb_driver ld_usb_driver = {
818         .name =         "ldusb",
819         .probe =        ld_usb_probe,
820         .disconnect =   ld_usb_disconnect,
821         .id_table =     ld_usb_table,
822 };
823
824 /**
825  *      ld_usb_init
826  */
827 static int __init ld_usb_init(void)
828 {
829         int retval;
830
831         /* register this driver with the USB subsystem */
832         retval = usb_register(&ld_usb_driver);
833         if (retval)
834                 err("usb_register failed for the %s driver. Error number %d\n", __FILE__, retval);
835
836         return retval;
837 }
838
839 /**
840  *      ld_usb_exit
841  */
842 static void __exit ld_usb_exit(void)
843 {
844         /* deregister this driver with the USB subsystem */
845         usb_deregister(&ld_usb_driver);
846 }
847
848 module_init(ld_usb_init);
849 module_exit(ld_usb_exit);
850