Merge git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog
[linux-2.6] / drivers / usb / misc / legousbtower.c
1 /*
2  * LEGO USB Tower driver
3  *
4  * Copyright (C) 2003 David Glance <davidgsf@sourceforge.net>
5  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
6  *
7  *      This program is free software; you can redistribute it and/or
8  *      modify it under the terms of the GNU General Public License as
9  *      published by the Free Software Foundation; either version 2 of
10  *      the License, or (at your option) any later version.
11  *
12  * derived from USB Skeleton driver - 0.5
13  * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
14  *
15  * History:
16  *
17  * 2001-10-13 - 0.1 js
18  *   - first version
19  * 2001-11-03 - 0.2 js
20  *   - simplified buffering, one-shot URBs for writing
21  * 2001-11-10 - 0.3 js
22  *   - removed IOCTL (setting power/mode is more complicated, postponed)
23  * 2001-11-28 - 0.4 js
24  *   - added vendor commands for mode of operation and power level in open
25  * 2001-12-04 - 0.5 js
26  *   - set IR mode by default (by oversight 0.4 set VLL mode)
27  * 2002-01-11 - 0.5? pcchan
28  *   - make read buffer reusable and work around bytes_to_write issue between
29  *     uhci and legusbtower
30  * 2002-09-23 - 0.52 david (david@csse.uwa.edu.au)
31  *   - imported into lejos project
32  *   - changed wake_up to wake_up_interruptible
33  *   - changed to use lego0 rather than tower0
34  *   - changed dbg() to use __func__ rather than deprecated __FUNCTION__
35  * 2003-01-12 - 0.53 david (david@csse.uwa.edu.au)
36  *   - changed read and write to write everything or
37  *     timeout (from a patch by Chris Riesen and Brett Thaeler driver)
38  *   - added ioctl functionality to set timeouts
39  * 2003-07-18 - 0.54 davidgsf (david@csse.uwa.edu.au)
40  *   - initial import into LegoUSB project
41  *   - merge of existing LegoUSB.c driver
42  * 2003-07-18 - 0.56 davidgsf (david@csse.uwa.edu.au)
43  *   - port to 2.6 style driver
44  * 2004-02-29 - 0.6 Juergen Stuber <starblue@users.sourceforge.net>
45  *   - fix locking
46  *   - unlink read URBs which are no longer needed
47  *   - allow increased buffer size, eliminates need for timeout on write
48  *   - have read URB running continuously
49  *   - added poll
50  *   - forbid seeking
51  *   - added nonblocking I/O
52  *   - changed back __func__ to __FUNCTION__
53  *   - read and log tower firmware version
54  *   - reset tower on probe, avoids failure of first write
55  * 2004-03-09 - 0.7 Juergen Stuber <starblue@users.sourceforge.net>
56  *   - timeout read now only after inactivity, shorten default accordingly
57  * 2004-03-11 - 0.8 Juergen Stuber <starblue@users.sourceforge.net>
58  *   - log major, minor instead of possibly confusing device filename
59  *   - whitespace cleanup
60  * 2004-03-12 - 0.9 Juergen Stuber <starblue@users.sourceforge.net>
61  *   - normalize whitespace in debug messages
62  *   - take care about endianness in control message responses
63  * 2004-03-13 - 0.91 Juergen Stuber <starblue@users.sourceforge.net>
64  *   - make default intervals longer to accommodate current EHCI driver
65  * 2004-03-19 - 0.92 Juergen Stuber <starblue@users.sourceforge.net>
66  *   - replaced atomic_t by memory barriers
67  * 2004-04-21 - 0.93 Juergen Stuber <starblue@users.sourceforge.net>
68  *   - wait for completion of write urb in release (needed for remotecontrol)
69  *   - corrected poll for write direction (missing negation)
70  * 2004-04-22 - 0.94 Juergen Stuber <starblue@users.sourceforge.net>
71  *   - make device locking interruptible
72  * 2004-04-30 - 0.95 Juergen Stuber <starblue@users.sourceforge.net>
73  *   - check for valid udev on resubmitting and unlinking urbs
74  * 2004-08-03 - 0.96 Juergen Stuber <starblue@users.sourceforge.net>
75  *   - move reset into open to clean out spurious data
76  */
77
78 #include <linux/kernel.h>
79 #include <linux/errno.h>
80 #include <linux/init.h>
81 #include <linux/slab.h>
82 #include <linux/module.h>
83 #include <linux/completion.h>
84 #include <linux/mutex.h>
85 #include <asm/uaccess.h>
86 #include <linux/usb.h>
87 #include <linux/poll.h>
88
89
90 #ifdef CONFIG_USB_DEBUG
91         static int debug = 4;
92 #else
93         static int debug = 0;
94 #endif
95
96 /* Use our own dbg macro */
97 #undef dbg
98 #define dbg(lvl, format, arg...) do { if (debug >= lvl) printk(KERN_DEBUG  __FILE__ ": " format "\n", ## arg); } while (0)
99
100
101 /* Version Information */
102 #define DRIVER_VERSION "v0.96"
103 #define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
104 #define DRIVER_DESC "LEGO USB Tower Driver"
105
106 /* Module parameters */
107 module_param(debug, int, S_IRUGO | S_IWUSR);
108 MODULE_PARM_DESC(debug, "Debug enabled or not");
109
110 /* The defaults are chosen to work with the latest versions of leJOS and NQC.
111  */
112
113 /* Some legacy software likes to receive packets in one piece.
114  * In this case read_buffer_size should exceed the maximal packet length
115  * (417 for datalog uploads), and packet_timeout should be set.
116  */
117 static int read_buffer_size = 480;
118 module_param(read_buffer_size, int, 0);
119 MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
120
121 /* Some legacy software likes to send packets in one piece.
122  * In this case write_buffer_size should exceed the maximal packet length
123  * (417 for firmware and program downloads).
124  * A problem with long writes is that the following read may time out
125  * if the software is not prepared to wait long enough.
126  */
127 static int write_buffer_size = 480;
128 module_param(write_buffer_size, int, 0);
129 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
130
131 /* Some legacy software expects reads to contain whole LASM packets.
132  * To achieve this, characters which arrive before a packet timeout
133  * occurs will be returned in a single read operation.
134  * A problem with long reads is that the software may time out
135  * if it is not prepared to wait long enough.
136  * The packet timeout should be greater than the time between the
137  * reception of subsequent characters, which should arrive about
138  * every 5ms for the standard 2400 baud.
139  * Set it to 0 to disable.
140  */
141 static int packet_timeout = 50;
142 module_param(packet_timeout, int, 0);
143 MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
144
145 /* Some legacy software expects blocking reads to time out.
146  * Timeout occurs after the specified time of read and write inactivity.
147  * Set it to 0 to disable.
148  */
149 static int read_timeout = 200;
150 module_param(read_timeout, int, 0);
151 MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
152
153 /* As of kernel version 2.6.4 ehci-hcd uses an
154  * "only one interrupt transfer per frame" shortcut
155  * to simplify the scheduling of periodic transfers.
156  * This conflicts with our standard 1ms intervals for in and out URBs.
157  * We use default intervals of 2ms for in and 8ms for out transfers,
158  * which is fast enough for 2400 baud and allows a small additional load.
159  * Increase the interval to allow more devices that do interrupt transfers,
160  * or set to 0 to use the standard interval from the endpoint descriptors.
161  */
162 static int interrupt_in_interval = 2;
163 module_param(interrupt_in_interval, int, 0);
164 MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
165
166 static int interrupt_out_interval = 8;
167 module_param(interrupt_out_interval, int, 0);
168 MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
169
170 /* Define these values to match your device */
171 #define LEGO_USB_TOWER_VENDOR_ID        0x0694
172 #define LEGO_USB_TOWER_PRODUCT_ID       0x0001
173
174 /* Vendor requests */
175 #define LEGO_USB_TOWER_REQUEST_RESET            0x04
176 #define LEGO_USB_TOWER_REQUEST_GET_VERSION      0xFD
177
178 struct tower_reset_reply {
179         __le16 size;            /* little-endian */
180         __u8 err_code;
181         __u8 spare;
182 } __attribute__ ((packed));
183
184 struct tower_get_version_reply {
185         __le16 size;            /* little-endian */
186         __u8 err_code;
187         __u8 spare;
188         __u8 major;
189         __u8 minor;
190         __le16 build_no;                /* little-endian */
191 } __attribute__ ((packed));
192
193
194 /* table of devices that work with this driver */
195 static struct usb_device_id tower_table [] = {
196         { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
197         { }                                     /* Terminating entry */
198 };
199
200 MODULE_DEVICE_TABLE (usb, tower_table);
201 static DEFINE_MUTEX(open_disc_mutex);
202
203 #define LEGO_USB_TOWER_MINOR_BASE       160
204
205
206 /* Structure to hold all of our device specific stuff */
207 struct lego_usb_tower {
208         struct semaphore        sem;            /* locks this structure */
209         struct usb_device*      udev;           /* save off the usb device pointer */
210         unsigned char           minor;          /* the starting minor number for this device */
211
212         int                     open_count;     /* number of times this port has been opened */
213
214         char*                   read_buffer;
215         size_t                  read_buffer_length; /* this much came in */
216         size_t                  read_packet_length; /* this much will be returned on read */
217         spinlock_t              read_buffer_lock;
218         int                     packet_timeout_jiffies;
219         unsigned long           read_last_arrival;
220
221         wait_queue_head_t       read_wait;
222         wait_queue_head_t       write_wait;
223
224         char*                   interrupt_in_buffer;
225         struct usb_endpoint_descriptor* interrupt_in_endpoint;
226         struct urb*             interrupt_in_urb;
227         int                     interrupt_in_interval;
228         int                     interrupt_in_running;
229         int                     interrupt_in_done;
230
231         char*                   interrupt_out_buffer;
232         struct usb_endpoint_descriptor* interrupt_out_endpoint;
233         struct urb*             interrupt_out_urb;
234         int                     interrupt_out_interval;
235         int                     interrupt_out_busy;
236
237 };
238
239
240 /* local function prototypes */
241 static ssize_t tower_read       (struct file *file, char __user *buffer, size_t count, loff_t *ppos);
242 static ssize_t tower_write      (struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
243 static inline void tower_delete (struct lego_usb_tower *dev);
244 static int tower_open           (struct inode *inode, struct file *file);
245 static int tower_release        (struct inode *inode, struct file *file);
246 static unsigned int tower_poll  (struct file *file, poll_table *wait);
247 static loff_t tower_llseek      (struct file *file, loff_t off, int whence);
248
249 static void tower_abort_transfers (struct lego_usb_tower *dev);
250 static void tower_check_for_read_packet (struct lego_usb_tower *dev);
251 static void tower_interrupt_in_callback (struct urb *urb);
252 static void tower_interrupt_out_callback (struct urb *urb);
253
254 static int  tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
255 static void tower_disconnect    (struct usb_interface *interface);
256
257
258 /* file operations needed when we register this driver */
259 static const struct file_operations tower_fops = {
260         .owner =        THIS_MODULE,
261         .read  =        tower_read,
262         .write =        tower_write,
263         .open =         tower_open,
264         .release =      tower_release,
265         .poll =         tower_poll,
266         .llseek =       tower_llseek,
267 };
268
269 /*
270  * usb class driver info in order to get a minor number from the usb core,
271  * and to have the device registered with the driver core
272  */
273 static struct usb_class_driver tower_class = {
274         .name =         "legousbtower%d",
275         .fops =         &tower_fops,
276         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
277 };
278
279
280 /* usb specific object needed to register this driver with the usb subsystem */
281 static struct usb_driver tower_driver = {
282         .name =         "legousbtower",
283         .probe =        tower_probe,
284         .disconnect =   tower_disconnect,
285         .id_table =     tower_table,
286 };
287
288
289 /**
290  *      lego_usb_tower_debug_data
291  */
292 static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
293 {
294         int i;
295
296         if (debug < level)
297                 return;
298
299         printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
300         for (i = 0; i < size; ++i) {
301                 printk ("%.2x ", data[i]);
302         }
303         printk ("\n");
304 }
305
306
307 /**
308  *      tower_delete
309  */
310 static inline void tower_delete (struct lego_usb_tower *dev)
311 {
312         dbg(2, "%s: enter", __FUNCTION__);
313
314         tower_abort_transfers (dev);
315
316         /* free data structures */
317         usb_free_urb(dev->interrupt_in_urb);
318         usb_free_urb(dev->interrupt_out_urb);
319         kfree (dev->read_buffer);
320         kfree (dev->interrupt_in_buffer);
321         kfree (dev->interrupt_out_buffer);
322         kfree (dev);
323
324         dbg(2, "%s: leave", __FUNCTION__);
325 }
326
327
328 /**
329  *      tower_open
330  */
331 static int tower_open (struct inode *inode, struct file *file)
332 {
333         struct lego_usb_tower *dev = NULL;
334         int subminor;
335         int retval = 0;
336         struct usb_interface *interface;
337         struct tower_reset_reply reset_reply;
338         int result;
339
340         dbg(2, "%s: enter", __FUNCTION__);
341
342         nonseekable_open(inode, file);
343         subminor = iminor(inode);
344
345         interface = usb_find_interface (&tower_driver, subminor);
346
347         if (!interface) {
348                 err ("%s - error, can't find device for minor %d",
349                      __FUNCTION__, subminor);
350                 retval = -ENODEV;
351                 goto exit;
352         }
353
354         mutex_lock(&open_disc_mutex);
355         dev = usb_get_intfdata(interface);
356
357         if (!dev) {
358                 mutex_unlock(&open_disc_mutex);
359                 retval = -ENODEV;
360                 goto exit;
361         }
362
363         /* lock this device */
364         if (down_interruptible (&dev->sem)) {
365                 mutex_unlock(&open_disc_mutex);
366                 retval = -ERESTARTSYS;
367                 goto exit;
368         }
369
370
371         /* allow opening only once */
372         if (dev->open_count) {
373                 mutex_unlock(&open_disc_mutex);
374                 retval = -EBUSY;
375                 goto unlock_exit;
376         }
377         dev->open_count = 1;
378         mutex_unlock(&open_disc_mutex);
379
380         /* reset the tower */
381         result = usb_control_msg (dev->udev,
382                                   usb_rcvctrlpipe(dev->udev, 0),
383                                   LEGO_USB_TOWER_REQUEST_RESET,
384                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
385                                   0,
386                                   0,
387                                   &reset_reply,
388                                   sizeof(reset_reply),
389                                   1000);
390         if (result < 0) {
391                 err("LEGO USB Tower reset control request failed");
392                 retval = result;
393                 goto unlock_exit;
394         }
395
396         /* initialize in direction */
397         dev->read_buffer_length = 0;
398         dev->read_packet_length = 0;
399         usb_fill_int_urb (dev->interrupt_in_urb,
400                           dev->udev,
401                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
402                           dev->interrupt_in_buffer,
403                           le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
404                           tower_interrupt_in_callback,
405                           dev,
406                           dev->interrupt_in_interval);
407
408         dev->interrupt_in_running = 1;
409         dev->interrupt_in_done = 0;
410         mb();
411
412         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
413         if (retval) {
414                 err("Couldn't submit interrupt_in_urb %d", retval);
415                 dev->interrupt_in_running = 0;
416                 dev->open_count = 0;
417                 goto unlock_exit;
418         }
419
420         /* save device in the file's private structure */
421         file->private_data = dev;
422
423 unlock_exit:
424         up (&dev->sem);
425
426 exit:
427         dbg(2, "%s: leave, return value %d ", __FUNCTION__, retval);
428
429         return retval;
430 }
431
432 /**
433  *      tower_release
434  */
435 static int tower_release (struct inode *inode, struct file *file)
436 {
437         struct lego_usb_tower *dev;
438         int retval = 0;
439
440         dbg(2, "%s: enter", __FUNCTION__);
441
442         dev = (struct lego_usb_tower *)file->private_data;
443
444         if (dev == NULL) {
445                 dbg(1, "%s: object is NULL", __FUNCTION__);
446                 retval = -ENODEV;
447                 goto exit_nolock;
448         }
449
450         mutex_lock(&open_disc_mutex);
451         if (down_interruptible (&dev->sem)) {
452                 retval = -ERESTARTSYS;
453                 goto exit;
454         }
455
456         if (dev->open_count != 1) {
457                 dbg(1, "%s: device not opened exactly once", __FUNCTION__);
458                 retval = -ENODEV;
459                 goto unlock_exit;
460         }
461         if (dev->udev == NULL) {
462                 /* the device was unplugged before the file was released */
463                 up (&dev->sem); /* unlock here as tower_delete frees dev */
464                 tower_delete (dev);
465                 goto exit;
466         }
467
468         /* wait until write transfer is finished */
469         if (dev->interrupt_out_busy) {
470                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
471         }
472         tower_abort_transfers (dev);
473         dev->open_count = 0;
474
475 unlock_exit:
476         up (&dev->sem);
477
478 exit:
479         mutex_unlock(&open_disc_mutex);
480 exit_nolock:
481         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
482         return retval;
483 }
484
485
486 /**
487  *      tower_abort_transfers
488  *      aborts transfers and frees associated data structures
489  */
490 static void tower_abort_transfers (struct lego_usb_tower *dev)
491 {
492         dbg(2, "%s: enter", __FUNCTION__);
493
494         if (dev == NULL) {
495                 dbg(1, "%s: dev is null", __FUNCTION__);
496                 goto exit;
497         }
498
499         /* shutdown transfer */
500         if (dev->interrupt_in_running) {
501                 dev->interrupt_in_running = 0;
502                 mb();
503                 if (dev->udev)
504                         usb_kill_urb (dev->interrupt_in_urb);
505         }
506         if (dev->interrupt_out_busy && dev->udev)
507                 usb_kill_urb(dev->interrupt_out_urb);
508
509 exit:
510         dbg(2, "%s: leave", __FUNCTION__);
511 }
512
513
514 /**
515  *      tower_check_for_read_packet
516  *
517  *      To get correct semantics for signals and non-blocking I/O
518  *      with packetizing we pretend not to see any data in the read buffer
519  *      until it has been there unchanged for at least
520  *      dev->packet_timeout_jiffies, or until the buffer is full.
521  */
522 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
523 {
524         spin_lock_irq (&dev->read_buffer_lock);
525         if (!packet_timeout
526             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
527             || dev->read_buffer_length == read_buffer_size) {
528                 dev->read_packet_length = dev->read_buffer_length;
529         }
530         dev->interrupt_in_done = 0;
531         spin_unlock_irq (&dev->read_buffer_lock);
532 }
533
534
535 /**
536  *      tower_poll
537  */
538 static unsigned int tower_poll (struct file *file, poll_table *wait)
539 {
540         struct lego_usb_tower *dev;
541         unsigned int mask = 0;
542
543         dbg(2, "%s: enter", __FUNCTION__);
544
545         dev = file->private_data;
546
547         poll_wait(file, &dev->read_wait, wait);
548         poll_wait(file, &dev->write_wait, wait);
549
550         tower_check_for_read_packet(dev);
551         if (dev->read_packet_length > 0) {
552                 mask |= POLLIN | POLLRDNORM;
553         }
554         if (!dev->interrupt_out_busy) {
555                 mask |= POLLOUT | POLLWRNORM;
556         }
557
558         dbg(2, "%s: leave, mask = %d", __FUNCTION__, mask);
559
560         return mask;
561 }
562
563
564 /**
565  *      tower_llseek
566  */
567 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
568 {
569         return -ESPIPE;         /* unseekable */
570 }
571
572
573 /**
574  *      tower_read
575  */
576 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
577 {
578         struct lego_usb_tower *dev;
579         size_t bytes_to_read;
580         int i;
581         int retval = 0;
582         unsigned long timeout = 0;
583
584         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
585
586         dev = (struct lego_usb_tower *)file->private_data;
587
588         /* lock this object */
589         if (down_interruptible (&dev->sem)) {
590                 retval = -ERESTARTSYS;
591                 goto exit;
592         }
593
594         /* verify that the device wasn't unplugged */
595         if (dev->udev == NULL) {
596                 retval = -ENODEV;
597                 err("No device or device unplugged %d", retval);
598                 goto unlock_exit;
599         }
600
601         /* verify that we actually have some data to read */
602         if (count == 0) {
603                 dbg(1, "%s: read request of 0 bytes", __FUNCTION__);
604                 goto unlock_exit;
605         }
606
607         if (read_timeout) {
608                 timeout = jiffies + read_timeout * HZ / 1000;
609         }
610
611         /* wait for data */
612         tower_check_for_read_packet (dev);
613         while (dev->read_packet_length == 0) {
614                 if (file->f_flags & O_NONBLOCK) {
615                         retval = -EAGAIN;
616                         goto unlock_exit;
617                 }
618                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
619                 if (retval < 0) {
620                         goto unlock_exit;
621                 }
622
623                 /* reset read timeout during read or write activity */
624                 if (read_timeout
625                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
626                         timeout = jiffies + read_timeout * HZ / 1000;
627                 }
628                 /* check for read timeout */
629                 if (read_timeout && time_after (jiffies, timeout)) {
630                         retval = -ETIMEDOUT;
631                         goto unlock_exit;
632                 }
633                 tower_check_for_read_packet (dev);
634         }
635
636         /* copy the data from read_buffer into userspace */
637         bytes_to_read = min(count, dev->read_packet_length);
638
639         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
640                 retval = -EFAULT;
641                 goto unlock_exit;
642         }
643
644         spin_lock_irq (&dev->read_buffer_lock);
645         dev->read_buffer_length -= bytes_to_read;
646         dev->read_packet_length -= bytes_to_read;
647         for (i=0; i<dev->read_buffer_length; i++) {
648                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
649         }
650         spin_unlock_irq (&dev->read_buffer_lock);
651
652         retval = bytes_to_read;
653
654 unlock_exit:
655         /* unlock the device */
656         up (&dev->sem);
657
658 exit:
659         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
660         return retval;
661 }
662
663
664 /**
665  *      tower_write
666  */
667 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
668 {
669         struct lego_usb_tower *dev;
670         size_t bytes_to_write;
671         int retval = 0;
672
673         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
674
675         dev = (struct lego_usb_tower *)file->private_data;
676
677         /* lock this object */
678         if (down_interruptible (&dev->sem)) {
679                 retval = -ERESTARTSYS;
680                 goto exit;
681         }
682
683         /* verify that the device wasn't unplugged */
684         if (dev->udev == NULL) {
685                 retval = -ENODEV;
686                 err("No device or device unplugged %d", retval);
687                 goto unlock_exit;
688         }
689
690         /* verify that we actually have some data to write */
691         if (count == 0) {
692                 dbg(1, "%s: write request of 0 bytes", __FUNCTION__);
693                 goto unlock_exit;
694         }
695
696         /* wait until previous transfer is finished */
697         while (dev->interrupt_out_busy) {
698                 if (file->f_flags & O_NONBLOCK) {
699                         retval = -EAGAIN;
700                         goto unlock_exit;
701                 }
702                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
703                 if (retval) {
704                         goto unlock_exit;
705                 }
706         }
707
708         /* write the data into interrupt_out_buffer from userspace */
709         bytes_to_write = min_t(int, count, write_buffer_size);
710         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __FUNCTION__, count, bytes_to_write);
711
712         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
713                 retval = -EFAULT;
714                 goto unlock_exit;
715         }
716
717         /* send off the urb */
718         usb_fill_int_urb(dev->interrupt_out_urb,
719                          dev->udev,
720                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
721                          dev->interrupt_out_buffer,
722                          bytes_to_write,
723                          tower_interrupt_out_callback,
724                          dev,
725                          dev->interrupt_out_interval);
726
727         dev->interrupt_out_busy = 1;
728         wmb();
729
730         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
731         if (retval) {
732                 dev->interrupt_out_busy = 0;
733                 err("Couldn't submit interrupt_out_urb %d", retval);
734                 goto unlock_exit;
735         }
736         retval = bytes_to_write;
737
738 unlock_exit:
739         /* unlock the device */
740         up (&dev->sem);
741
742 exit:
743         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
744
745         return retval;
746 }
747
748
749 /**
750  *      tower_interrupt_in_callback
751  */
752 static void tower_interrupt_in_callback (struct urb *urb)
753 {
754         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
755         int status = urb->status;
756         int retval;
757
758         dbg(4, "%s: enter, status %d", __FUNCTION__, status);
759
760         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
761
762         if (status) {
763                 if (status == -ENOENT ||
764                     status == -ECONNRESET ||
765                     status == -ESHUTDOWN) {
766                         goto exit;
767                 } else {
768                         dbg(1, "%s: nonzero status received: %d", __FUNCTION__, status);
769                         goto resubmit; /* maybe we can recover */
770                 }
771         }
772
773         if (urb->actual_length > 0) {
774                 spin_lock (&dev->read_buffer_lock);
775                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
776                         memcpy (dev->read_buffer + dev->read_buffer_length,
777                                 dev->interrupt_in_buffer,
778                                 urb->actual_length);
779                         dev->read_buffer_length += urb->actual_length;
780                         dev->read_last_arrival = jiffies;
781                         dbg(3, "%s: received %d bytes", __FUNCTION__, urb->actual_length);
782                 } else {
783                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __FUNCTION__, urb->actual_length);
784                 }
785                 spin_unlock (&dev->read_buffer_lock);
786         }
787
788 resubmit:
789         /* resubmit if we're still running */
790         if (dev->interrupt_in_running && dev->udev) {
791                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
792                 if (retval) {
793                         err("%s: usb_submit_urb failed (%d)", __FUNCTION__, retval);
794                 }
795         }
796
797 exit:
798         dev->interrupt_in_done = 1;
799         wake_up_interruptible (&dev->read_wait);
800
801         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
802         dbg(4, "%s: leave, status %d", __FUNCTION__, status);
803 }
804
805
806 /**
807  *      tower_interrupt_out_callback
808  */
809 static void tower_interrupt_out_callback (struct urb *urb)
810 {
811         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
812         int status = urb->status;
813
814         dbg(4, "%s: enter, status %d", __FUNCTION__, status);
815         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
816
817         /* sync/async unlink faults aren't errors */
818         if (status && !(status == -ENOENT ||
819                         status == -ECONNRESET ||
820                         status == -ESHUTDOWN)) {
821                 dbg(1, "%s - nonzero write bulk status received: %d",
822                     __FUNCTION__, status);
823         }
824
825         dev->interrupt_out_busy = 0;
826         wake_up_interruptible(&dev->write_wait);
827
828         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
829         dbg(4, "%s: leave, status %d", __FUNCTION__, status);
830 }
831
832
833 /**
834  *      tower_probe
835  *
836  *      Called by the usb core when a new device is connected that it thinks
837  *      this driver might be interested in.
838  */
839 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
840 {
841         struct usb_device *udev = interface_to_usbdev(interface);
842         struct lego_usb_tower *dev = NULL;
843         struct usb_host_interface *iface_desc;
844         struct usb_endpoint_descriptor* endpoint;
845         struct tower_get_version_reply get_version_reply;
846         int i;
847         int retval = -ENOMEM;
848         int result;
849
850         dbg(2, "%s: enter", __FUNCTION__);
851
852         if (udev == NULL) {
853                 info ("udev is NULL.");
854         }
855
856         /* allocate memory for our device state and initialize it */
857
858         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
859
860         if (dev == NULL) {
861                 err ("Out of memory");
862                 goto exit;
863         }
864
865         init_MUTEX (&dev->sem);
866
867         dev->udev = udev;
868         dev->open_count = 0;
869
870         dev->read_buffer = NULL;
871         dev->read_buffer_length = 0;
872         dev->read_packet_length = 0;
873         spin_lock_init (&dev->read_buffer_lock);
874         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
875         dev->read_last_arrival = jiffies;
876
877         init_waitqueue_head (&dev->read_wait);
878         init_waitqueue_head (&dev->write_wait);
879
880         dev->interrupt_in_buffer = NULL;
881         dev->interrupt_in_endpoint = NULL;
882         dev->interrupt_in_urb = NULL;
883         dev->interrupt_in_running = 0;
884         dev->interrupt_in_done = 0;
885
886         dev->interrupt_out_buffer = NULL;
887         dev->interrupt_out_endpoint = NULL;
888         dev->interrupt_out_urb = NULL;
889         dev->interrupt_out_busy = 0;
890
891         iface_desc = interface->cur_altsetting;
892
893         /* set up the endpoint information */
894         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
895                 endpoint = &iface_desc->endpoint[i].desc;
896
897                 if (usb_endpoint_xfer_int(endpoint)) {
898                         if (usb_endpoint_dir_in(endpoint))
899                                 dev->interrupt_in_endpoint = endpoint;
900                         else
901                                 dev->interrupt_out_endpoint = endpoint;
902                 }
903         }
904         if(dev->interrupt_in_endpoint == NULL) {
905                 err("interrupt in endpoint not found");
906                 goto error;
907         }
908         if (dev->interrupt_out_endpoint == NULL) {
909                 err("interrupt out endpoint not found");
910                 goto error;
911         }
912
913         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
914         if (!dev->read_buffer) {
915                 err("Couldn't allocate read_buffer");
916                 goto error;
917         }
918         dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
919         if (!dev->interrupt_in_buffer) {
920                 err("Couldn't allocate interrupt_in_buffer");
921                 goto error;
922         }
923         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
924         if (!dev->interrupt_in_urb) {
925                 err("Couldn't allocate interrupt_in_urb");
926                 goto error;
927         }
928         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
929         if (!dev->interrupt_out_buffer) {
930                 err("Couldn't allocate interrupt_out_buffer");
931                 goto error;
932         }
933         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
934         if (!dev->interrupt_out_urb) {
935                 err("Couldn't allocate interrupt_out_urb");
936                 goto error;
937         }
938         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
939         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
940
941         /* we can register the device now, as it is ready */
942         usb_set_intfdata (interface, dev);
943
944         retval = usb_register_dev (interface, &tower_class);
945
946         if (retval) {
947                 /* something prevented us from registering this driver */
948                 err ("Not able to get a minor for this device.");
949                 usb_set_intfdata (interface, NULL);
950                 goto error;
951         }
952         dev->minor = interface->minor;
953
954         /* let the user know what node this device is now attached to */
955         info ("LEGO USB Tower #%d now attached to major %d minor %d", (dev->minor - LEGO_USB_TOWER_MINOR_BASE), USB_MAJOR, dev->minor);
956
957         /* get the firmware version and log it */
958         result = usb_control_msg (udev,
959                                   usb_rcvctrlpipe(udev, 0),
960                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
961                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
962                                   0,
963                                   0,
964                                   &get_version_reply,
965                                   sizeof(get_version_reply),
966                                   1000);
967         if (result < 0) {
968                 err("LEGO USB Tower get version control request failed");
969                 retval = result;
970                 goto error;
971         }
972         info("LEGO USB Tower firmware version is %d.%d build %d",
973              get_version_reply.major,
974              get_version_reply.minor,
975              le16_to_cpu(get_version_reply.build_no));
976
977
978 exit:
979         dbg(2, "%s: leave, return value 0x%.8lx (dev)", __FUNCTION__, (long) dev);
980
981         return retval;
982
983 error:
984         tower_delete(dev);
985         return retval;
986 }
987
988
989 /**
990  *      tower_disconnect
991  *
992  *      Called by the usb core when the device is removed from the system.
993  */
994 static void tower_disconnect (struct usb_interface *interface)
995 {
996         struct lego_usb_tower *dev;
997         int minor;
998
999         dbg(2, "%s: enter", __FUNCTION__);
1000
1001         dev = usb_get_intfdata (interface);
1002         mutex_lock(&open_disc_mutex);
1003         usb_set_intfdata (interface, NULL);
1004
1005         minor = dev->minor;
1006
1007         /* give back our minor */
1008         usb_deregister_dev (interface, &tower_class);
1009
1010         down (&dev->sem);
1011         mutex_unlock(&open_disc_mutex);
1012
1013         /* if the device is not opened, then we clean up right now */
1014         if (!dev->open_count) {
1015                 up (&dev->sem);
1016                 tower_delete (dev);
1017         } else {
1018                 dev->udev = NULL;
1019                 up (&dev->sem);
1020         }
1021
1022         info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));
1023
1024         dbg(2, "%s: leave", __FUNCTION__);
1025 }
1026
1027
1028
1029 /**
1030  *      lego_usb_tower_init
1031  */
1032 static int __init lego_usb_tower_init(void)
1033 {
1034         int result;
1035         int retval = 0;
1036
1037         dbg(2, "%s: enter", __FUNCTION__);
1038
1039         /* register this driver with the USB subsystem */
1040         result = usb_register(&tower_driver);
1041         if (result < 0) {
1042                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1043                 retval = -1;
1044                 goto exit;
1045         }
1046
1047         info(DRIVER_DESC " " DRIVER_VERSION);
1048
1049 exit:
1050         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
1051
1052         return retval;
1053 }
1054
1055
1056 /**
1057  *      lego_usb_tower_exit
1058  */
1059 static void __exit lego_usb_tower_exit(void)
1060 {
1061         dbg(2, "%s: enter", __FUNCTION__);
1062
1063         /* deregister this driver with the USB subsystem */
1064         usb_deregister (&tower_driver);
1065
1066         dbg(2, "%s: leave", __FUNCTION__);
1067 }
1068
1069 module_init (lego_usb_tower_init);
1070 module_exit (lego_usb_tower_exit);
1071
1072 MODULE_AUTHOR(DRIVER_AUTHOR);
1073 MODULE_DESCRIPTION(DRIVER_DESC);
1074 #ifdef MODULE_LICENSE
1075 MODULE_LICENSE("GPL");
1076 #endif