Merge git://git.infradead.org/mtd-2.6
[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
202 #define LEGO_USB_TOWER_MINOR_BASE       160
203
204
205 /* Structure to hold all of our device specific stuff */
206 struct lego_usb_tower {
207         struct semaphore        sem;            /* locks this structure */
208         struct usb_device*      udev;           /* save off the usb device pointer */
209         unsigned char           minor;          /* the starting minor number for this device */
210
211         int                     open_count;     /* number of times this port has been opened */
212
213         char*                   read_buffer;
214         size_t                  read_buffer_length; /* this much came in */
215         size_t                  read_packet_length; /* this much will be returned on read */
216         spinlock_t              read_buffer_lock;
217         int                     packet_timeout_jiffies;
218         unsigned long           read_last_arrival;
219
220         wait_queue_head_t       read_wait;
221         wait_queue_head_t       write_wait;
222
223         char*                   interrupt_in_buffer;
224         struct usb_endpoint_descriptor* interrupt_in_endpoint;
225         struct urb*             interrupt_in_urb;
226         int                     interrupt_in_interval;
227         int                     interrupt_in_running;
228         int                     interrupt_in_done;
229
230         char*                   interrupt_out_buffer;
231         struct usb_endpoint_descriptor* interrupt_out_endpoint;
232         struct urb*             interrupt_out_urb;
233         int                     interrupt_out_interval;
234         int                     interrupt_out_busy;
235
236 };
237
238
239 /* local function prototypes */
240 static ssize_t tower_read       (struct file *file, char __user *buffer, size_t count, loff_t *ppos);
241 static ssize_t tower_write      (struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
242 static inline void tower_delete (struct lego_usb_tower *dev);
243 static int tower_open           (struct inode *inode, struct file *file);
244 static int tower_release        (struct inode *inode, struct file *file);
245 static unsigned int tower_poll  (struct file *file, poll_table *wait);
246 static loff_t tower_llseek      (struct file *file, loff_t off, int whence);
247
248 static void tower_abort_transfers (struct lego_usb_tower *dev);
249 static void tower_check_for_read_packet (struct lego_usb_tower *dev);
250 static void tower_interrupt_in_callback (struct urb *urb);
251 static void tower_interrupt_out_callback (struct urb *urb);
252
253 static int  tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
254 static void tower_disconnect    (struct usb_interface *interface);
255
256
257 /* prevent races between open() and disconnect */
258 static DEFINE_MUTEX (disconnect_mutex);
259
260 /* file operations needed when we register this driver */
261 static const struct file_operations tower_fops = {
262         .owner =        THIS_MODULE,
263         .read  =        tower_read,
264         .write =        tower_write,
265         .open =         tower_open,
266         .release =      tower_release,
267         .poll =         tower_poll,
268         .llseek =       tower_llseek,
269 };
270
271 /*
272  * usb class driver info in order to get a minor number from the usb core,
273  * and to have the device registered with the driver core
274  */
275 static struct usb_class_driver tower_class = {
276         .name =         "legousbtower%d",
277         .fops =         &tower_fops,
278         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
279 };
280
281
282 /* usb specific object needed to register this driver with the usb subsystem */
283 static struct usb_driver tower_driver = {
284         .name =         "legousbtower",
285         .probe =        tower_probe,
286         .disconnect =   tower_disconnect,
287         .id_table =     tower_table,
288 };
289
290
291 /**
292  *      lego_usb_tower_debug_data
293  */
294 static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
295 {
296         int i;
297
298         if (debug < level)
299                 return;
300
301         printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
302         for (i = 0; i < size; ++i) {
303                 printk ("%.2x ", data[i]);
304         }
305         printk ("\n");
306 }
307
308
309 /**
310  *      tower_delete
311  */
312 static inline void tower_delete (struct lego_usb_tower *dev)
313 {
314         dbg(2, "%s: enter", __FUNCTION__);
315
316         tower_abort_transfers (dev);
317
318         /* free data structures */
319         usb_free_urb(dev->interrupt_in_urb);
320         usb_free_urb(dev->interrupt_out_urb);
321         kfree (dev->read_buffer);
322         kfree (dev->interrupt_in_buffer);
323         kfree (dev->interrupt_out_buffer);
324         kfree (dev);
325
326         dbg(2, "%s: leave", __FUNCTION__);
327 }
328
329
330 /**
331  *      tower_open
332  */
333 static int tower_open (struct inode *inode, struct file *file)
334 {
335         struct lego_usb_tower *dev = NULL;
336         int subminor;
337         int retval = 0;
338         struct usb_interface *interface;
339         struct tower_reset_reply reset_reply;
340         int result;
341
342         dbg(2, "%s: enter", __FUNCTION__);
343
344         nonseekable_open(inode, file);
345         subminor = iminor(inode);
346
347         mutex_lock (&disconnect_mutex);
348
349         interface = usb_find_interface (&tower_driver, subminor);
350
351         if (!interface) {
352                 err ("%s - error, can't find device for minor %d",
353                      __FUNCTION__, subminor);
354                 retval = -ENODEV;
355                 goto unlock_disconnect_exit;
356         }
357
358         dev = usb_get_intfdata(interface);
359
360         if (!dev) {
361                 retval = -ENODEV;
362                 goto unlock_disconnect_exit;
363         }
364
365         /* lock this device */
366         if (down_interruptible (&dev->sem)) {
367                 retval = -ERESTARTSYS;
368                 goto unlock_disconnect_exit;
369         }
370
371         /* allow opening only once */
372         if (dev->open_count) {
373                 retval = -EBUSY;
374                 goto unlock_exit;
375         }
376         dev->open_count = 1;
377
378         /* reset the tower */
379         result = usb_control_msg (dev->udev,
380                                   usb_rcvctrlpipe(dev->udev, 0),
381                                   LEGO_USB_TOWER_REQUEST_RESET,
382                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
383                                   0,
384                                   0,
385                                   &reset_reply,
386                                   sizeof(reset_reply),
387                                   1000);
388         if (result < 0) {
389                 err("LEGO USB Tower reset control request failed");
390                 retval = result;
391                 goto unlock_exit;
392         }
393
394         /* initialize in direction */
395         dev->read_buffer_length = 0;
396         dev->read_packet_length = 0;
397         usb_fill_int_urb (dev->interrupt_in_urb,
398                           dev->udev,
399                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
400                           dev->interrupt_in_buffer,
401                           le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
402                           tower_interrupt_in_callback,
403                           dev,
404                           dev->interrupt_in_interval);
405
406         dev->interrupt_in_running = 1;
407         dev->interrupt_in_done = 0;
408         mb();
409
410         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
411         if (retval) {
412                 err("Couldn't submit interrupt_in_urb %d", retval);
413                 dev->interrupt_in_running = 0;
414                 dev->open_count = 0;
415                 goto unlock_exit;
416         }
417
418         /* save device in the file's private structure */
419         file->private_data = dev;
420
421 unlock_exit:
422         up (&dev->sem);
423
424 unlock_disconnect_exit:
425         mutex_unlock (&disconnect_mutex);
426
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;
448         }
449
450         if (down_interruptible (&dev->sem)) {
451                 retval = -ERESTARTSYS;
452                 goto exit;
453         }
454
455         if (dev->open_count != 1) {
456                 dbg(1, "%s: device not opened exactly once", __FUNCTION__);
457                 retval = -ENODEV;
458                 goto unlock_exit;
459         }
460         if (dev->udev == NULL) {
461                 /* the device was unplugged before the file was released */
462                 up (&dev->sem); /* unlock here as tower_delete frees dev */
463                 tower_delete (dev);
464                 goto exit;
465         }
466
467         /* wait until write transfer is finished */
468         if (dev->interrupt_out_busy) {
469                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
470         }
471         tower_abort_transfers (dev);
472         dev->open_count = 0;
473
474 unlock_exit:
475         up (&dev->sem);
476
477 exit:
478         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
479         return retval;
480 }
481
482
483 /**
484  *      tower_abort_transfers
485  *      aborts transfers and frees associated data structures
486  */
487 static void tower_abort_transfers (struct lego_usb_tower *dev)
488 {
489         dbg(2, "%s: enter", __FUNCTION__);
490
491         if (dev == NULL) {
492                 dbg(1, "%s: dev is null", __FUNCTION__);
493                 goto exit;
494         }
495
496         /* shutdown transfer */
497         if (dev->interrupt_in_running) {
498                 dev->interrupt_in_running = 0;
499                 mb();
500                 if (dev->udev)
501                         usb_kill_urb (dev->interrupt_in_urb);
502         }
503         if (dev->interrupt_out_busy && dev->udev)
504                 usb_kill_urb(dev->interrupt_out_urb);
505
506 exit:
507         dbg(2, "%s: leave", __FUNCTION__);
508 }
509
510
511 /**
512  *      tower_check_for_read_packet
513  *
514  *      To get correct semantics for signals and non-blocking I/O
515  *      with packetizing we pretend not to see any data in the read buffer
516  *      until it has been there unchanged for at least
517  *      dev->packet_timeout_jiffies, or until the buffer is full.
518  */
519 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
520 {
521         spin_lock_irq (&dev->read_buffer_lock);
522         if (!packet_timeout
523             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
524             || dev->read_buffer_length == read_buffer_size) {
525                 dev->read_packet_length = dev->read_buffer_length;
526         }
527         dev->interrupt_in_done = 0;
528         spin_unlock_irq (&dev->read_buffer_lock);
529 }
530
531
532 /**
533  *      tower_poll
534  */
535 static unsigned int tower_poll (struct file *file, poll_table *wait)
536 {
537         struct lego_usb_tower *dev;
538         unsigned int mask = 0;
539
540         dbg(2, "%s: enter", __FUNCTION__);
541
542         dev = file->private_data;
543
544         poll_wait(file, &dev->read_wait, wait);
545         poll_wait(file, &dev->write_wait, wait);
546
547         tower_check_for_read_packet(dev);
548         if (dev->read_packet_length > 0) {
549                 mask |= POLLIN | POLLRDNORM;
550         }
551         if (!dev->interrupt_out_busy) {
552                 mask |= POLLOUT | POLLWRNORM;
553         }
554
555         dbg(2, "%s: leave, mask = %d", __FUNCTION__, mask);
556
557         return mask;
558 }
559
560
561 /**
562  *      tower_llseek
563  */
564 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
565 {
566         return -ESPIPE;         /* unseekable */
567 }
568
569
570 /**
571  *      tower_read
572  */
573 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
574 {
575         struct lego_usb_tower *dev;
576         size_t bytes_to_read;
577         int i;
578         int retval = 0;
579         unsigned long timeout = 0;
580
581         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
582
583         dev = (struct lego_usb_tower *)file->private_data;
584
585         /* lock this object */
586         if (down_interruptible (&dev->sem)) {
587                 retval = -ERESTARTSYS;
588                 goto exit;
589         }
590
591         /* verify that the device wasn't unplugged */
592         if (dev->udev == NULL) {
593                 retval = -ENODEV;
594                 err("No device or device unplugged %d", retval);
595                 goto unlock_exit;
596         }
597
598         /* verify that we actually have some data to read */
599         if (count == 0) {
600                 dbg(1, "%s: read request of 0 bytes", __FUNCTION__);
601                 goto unlock_exit;
602         }
603
604         if (read_timeout) {
605                 timeout = jiffies + read_timeout * HZ / 1000;
606         }
607
608         /* wait for data */
609         tower_check_for_read_packet (dev);
610         while (dev->read_packet_length == 0) {
611                 if (file->f_flags & O_NONBLOCK) {
612                         retval = -EAGAIN;
613                         goto unlock_exit;
614                 }
615                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
616                 if (retval < 0) {
617                         goto unlock_exit;
618                 }
619
620                 /* reset read timeout during read or write activity */
621                 if (read_timeout
622                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
623                         timeout = jiffies + read_timeout * HZ / 1000;
624                 }
625                 /* check for read timeout */
626                 if (read_timeout && time_after (jiffies, timeout)) {
627                         retval = -ETIMEDOUT;
628                         goto unlock_exit;
629                 }
630                 tower_check_for_read_packet (dev);
631         }
632
633         /* copy the data from read_buffer into userspace */
634         bytes_to_read = min(count, dev->read_packet_length);
635
636         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
637                 retval = -EFAULT;
638                 goto unlock_exit;
639         }
640
641         spin_lock_irq (&dev->read_buffer_lock);
642         dev->read_buffer_length -= bytes_to_read;
643         dev->read_packet_length -= bytes_to_read;
644         for (i=0; i<dev->read_buffer_length; i++) {
645                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
646         }
647         spin_unlock_irq (&dev->read_buffer_lock);
648
649         retval = bytes_to_read;
650
651 unlock_exit:
652         /* unlock the device */
653         up (&dev->sem);
654
655 exit:
656         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
657         return retval;
658 }
659
660
661 /**
662  *      tower_write
663  */
664 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
665 {
666         struct lego_usb_tower *dev;
667         size_t bytes_to_write;
668         int retval = 0;
669
670         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
671
672         dev = (struct lego_usb_tower *)file->private_data;
673
674         /* lock this object */
675         if (down_interruptible (&dev->sem)) {
676                 retval = -ERESTARTSYS;
677                 goto exit;
678         }
679
680         /* verify that the device wasn't unplugged */
681         if (dev->udev == NULL) {
682                 retval = -ENODEV;
683                 err("No device or device unplugged %d", retval);
684                 goto unlock_exit;
685         }
686
687         /* verify that we actually have some data to write */
688         if (count == 0) {
689                 dbg(1, "%s: write request of 0 bytes", __FUNCTION__);
690                 goto unlock_exit;
691         }
692
693         /* wait until previous transfer is finished */
694         while (dev->interrupt_out_busy) {
695                 if (file->f_flags & O_NONBLOCK) {
696                         retval = -EAGAIN;
697                         goto unlock_exit;
698                 }
699                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
700                 if (retval) {
701                         goto unlock_exit;
702                 }
703         }
704
705         /* write the data into interrupt_out_buffer from userspace */
706         bytes_to_write = min_t(int, count, write_buffer_size);
707         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __FUNCTION__, count, bytes_to_write);
708
709         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
710                 retval = -EFAULT;
711                 goto unlock_exit;
712         }
713
714         /* send off the urb */
715         usb_fill_int_urb(dev->interrupt_out_urb,
716                          dev->udev,
717                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
718                          dev->interrupt_out_buffer,
719                          bytes_to_write,
720                          tower_interrupt_out_callback,
721                          dev,
722                          dev->interrupt_out_interval);
723
724         dev->interrupt_out_busy = 1;
725         wmb();
726
727         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
728         if (retval) {
729                 dev->interrupt_out_busy = 0;
730                 err("Couldn't submit interrupt_out_urb %d", retval);
731                 goto unlock_exit;
732         }
733         retval = bytes_to_write;
734
735 unlock_exit:
736         /* unlock the device */
737         up (&dev->sem);
738
739 exit:
740         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
741
742         return retval;
743 }
744
745
746 /**
747  *      tower_interrupt_in_callback
748  */
749 static void tower_interrupt_in_callback (struct urb *urb)
750 {
751         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
752         int retval;
753
754         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
755
756         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
757
758         if (urb->status) {
759                 if (urb->status == -ENOENT ||
760                     urb->status == -ECONNRESET ||
761                     urb->status == -ESHUTDOWN) {
762                         goto exit;
763                 } else {
764                         dbg(1, "%s: nonzero status received: %d", __FUNCTION__, urb->status);
765                         goto resubmit; /* maybe we can recover */
766                 }
767         }
768
769         if (urb->actual_length > 0) {
770                 spin_lock (&dev->read_buffer_lock);
771                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
772                         memcpy (dev->read_buffer + dev->read_buffer_length,
773                                 dev->interrupt_in_buffer,
774                                 urb->actual_length);
775                         dev->read_buffer_length += urb->actual_length;
776                         dev->read_last_arrival = jiffies;
777                         dbg(3, "%s: received %d bytes", __FUNCTION__, urb->actual_length);
778                 } else {
779                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __FUNCTION__, urb->actual_length);
780                 }
781                 spin_unlock (&dev->read_buffer_lock);
782         }
783
784 resubmit:
785         /* resubmit if we're still running */
786         if (dev->interrupt_in_running && dev->udev) {
787                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
788                 if (retval) {
789                         err("%s: usb_submit_urb failed (%d)", __FUNCTION__, retval);
790                 }
791         }
792
793 exit:
794         dev->interrupt_in_done = 1;
795         wake_up_interruptible (&dev->read_wait);
796
797         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
798         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
799 }
800
801
802 /**
803  *      tower_interrupt_out_callback
804  */
805 static void tower_interrupt_out_callback (struct urb *urb)
806 {
807         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
808
809         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
810         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
811
812         /* sync/async unlink faults aren't errors */
813         if (urb->status && !(urb->status == -ENOENT ||
814                              urb->status == -ECONNRESET ||
815                              urb->status == -ESHUTDOWN)) {
816                 dbg(1, "%s - nonzero write bulk status received: %d",
817                     __FUNCTION__, urb->status);
818         }
819
820         dev->interrupt_out_busy = 0;
821         wake_up_interruptible(&dev->write_wait);
822
823         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
824         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
825 }
826
827
828 /**
829  *      tower_probe
830  *
831  *      Called by the usb core when a new device is connected that it thinks
832  *      this driver might be interested in.
833  */
834 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
835 {
836         struct usb_device *udev = interface_to_usbdev(interface);
837         struct lego_usb_tower *dev = NULL;
838         struct usb_host_interface *iface_desc;
839         struct usb_endpoint_descriptor* endpoint;
840         struct tower_get_version_reply get_version_reply;
841         int i;
842         int retval = -ENOMEM;
843         int result;
844
845         dbg(2, "%s: enter", __FUNCTION__);
846
847         if (udev == NULL) {
848                 info ("udev is NULL.");
849         }
850
851         /* allocate memory for our device state and initialize it */
852
853         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
854
855         if (dev == NULL) {
856                 err ("Out of memory");
857                 goto exit;
858         }
859
860         init_MUTEX (&dev->sem);
861
862         dev->udev = udev;
863         dev->open_count = 0;
864
865         dev->read_buffer = NULL;
866         dev->read_buffer_length = 0;
867         dev->read_packet_length = 0;
868         spin_lock_init (&dev->read_buffer_lock);
869         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
870         dev->read_last_arrival = jiffies;
871
872         init_waitqueue_head (&dev->read_wait);
873         init_waitqueue_head (&dev->write_wait);
874
875         dev->interrupt_in_buffer = NULL;
876         dev->interrupt_in_endpoint = NULL;
877         dev->interrupt_in_urb = NULL;
878         dev->interrupt_in_running = 0;
879         dev->interrupt_in_done = 0;
880
881         dev->interrupt_out_buffer = NULL;
882         dev->interrupt_out_endpoint = NULL;
883         dev->interrupt_out_urb = NULL;
884         dev->interrupt_out_busy = 0;
885
886         iface_desc = interface->cur_altsetting;
887
888         /* set up the endpoint information */
889         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
890                 endpoint = &iface_desc->endpoint[i].desc;
891
892                 if (usb_endpoint_xfer_int(endpoint)) {
893                         if (usb_endpoint_dir_in(endpoint))
894                                 dev->interrupt_in_endpoint = endpoint;
895                         else
896                                 dev->interrupt_out_endpoint = endpoint;
897                 }
898         }
899         if(dev->interrupt_in_endpoint == NULL) {
900                 err("interrupt in endpoint not found");
901                 goto error;
902         }
903         if (dev->interrupt_out_endpoint == NULL) {
904                 err("interrupt out endpoint not found");
905                 goto error;
906         }
907
908         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
909         if (!dev->read_buffer) {
910                 err("Couldn't allocate read_buffer");
911                 goto error;
912         }
913         dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
914         if (!dev->interrupt_in_buffer) {
915                 err("Couldn't allocate interrupt_in_buffer");
916                 goto error;
917         }
918         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
919         if (!dev->interrupt_in_urb) {
920                 err("Couldn't allocate interrupt_in_urb");
921                 goto error;
922         }
923         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
924         if (!dev->interrupt_out_buffer) {
925                 err("Couldn't allocate interrupt_out_buffer");
926                 goto error;
927         }
928         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
929         if (!dev->interrupt_out_urb) {
930                 err("Couldn't allocate interrupt_out_urb");
931                 goto error;
932         }
933         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
934         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
935
936         /* we can register the device now, as it is ready */
937         usb_set_intfdata (interface, dev);
938
939         retval = usb_register_dev (interface, &tower_class);
940
941         if (retval) {
942                 /* something prevented us from registering this driver */
943                 err ("Not able to get a minor for this device.");
944                 usb_set_intfdata (interface, NULL);
945                 goto error;
946         }
947         dev->minor = interface->minor;
948
949         /* let the user know what node this device is now attached to */
950         info ("LEGO USB Tower #%d now attached to major %d minor %d", (dev->minor - LEGO_USB_TOWER_MINOR_BASE), USB_MAJOR, dev->minor);
951
952         /* get the firmware version and log it */
953         result = usb_control_msg (udev,
954                                   usb_rcvctrlpipe(udev, 0),
955                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
956                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
957                                   0,
958                                   0,
959                                   &get_version_reply,
960                                   sizeof(get_version_reply),
961                                   1000);
962         if (result < 0) {
963                 err("LEGO USB Tower get version control request failed");
964                 retval = result;
965                 goto error;
966         }
967         info("LEGO USB Tower firmware version is %d.%d build %d",
968              get_version_reply.major,
969              get_version_reply.minor,
970              le16_to_cpu(get_version_reply.build_no));
971
972
973 exit:
974         dbg(2, "%s: leave, return value 0x%.8lx (dev)", __FUNCTION__, (long) dev);
975
976         return retval;
977
978 error:
979         tower_delete(dev);
980         return retval;
981 }
982
983
984 /**
985  *      tower_disconnect
986  *
987  *      Called by the usb core when the device is removed from the system.
988  */
989 static void tower_disconnect (struct usb_interface *interface)
990 {
991         struct lego_usb_tower *dev;
992         int minor;
993
994         dbg(2, "%s: enter", __FUNCTION__);
995
996         mutex_lock (&disconnect_mutex);
997
998         dev = usb_get_intfdata (interface);
999         usb_set_intfdata (interface, NULL);
1000
1001
1002         down (&dev->sem);
1003
1004         minor = dev->minor;
1005
1006         /* give back our minor */
1007         usb_deregister_dev (interface, &tower_class);
1008
1009         /* if the device is not opened, then we clean up right now */
1010         if (!dev->open_count) {
1011                 up (&dev->sem);
1012                 tower_delete (dev);
1013         } else {
1014                 dev->udev = NULL;
1015                 up (&dev->sem);
1016         }
1017
1018         mutex_unlock (&disconnect_mutex);
1019
1020         info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));
1021
1022         dbg(2, "%s: leave", __FUNCTION__);
1023 }
1024
1025
1026
1027 /**
1028  *      lego_usb_tower_init
1029  */
1030 static int __init lego_usb_tower_init(void)
1031 {
1032         int result;
1033         int retval = 0;
1034
1035         dbg(2, "%s: enter", __FUNCTION__);
1036
1037         /* register this driver with the USB subsystem */
1038         result = usb_register(&tower_driver);
1039         if (result < 0) {
1040                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1041                 retval = -1;
1042                 goto exit;
1043         }
1044
1045         info(DRIVER_DESC " " DRIVER_VERSION);
1046
1047 exit:
1048         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
1049
1050         return retval;
1051 }
1052
1053
1054 /**
1055  *      lego_usb_tower_exit
1056  */
1057 static void __exit lego_usb_tower_exit(void)
1058 {
1059         dbg(2, "%s: enter", __FUNCTION__);
1060
1061         /* deregister this driver with the USB subsystem */
1062         usb_deregister (&tower_driver);
1063
1064         dbg(2, "%s: leave", __FUNCTION__);
1065 }
1066
1067 module_init (lego_usb_tower_init);
1068 module_exit (lego_usb_tower_exit);
1069
1070 MODULE_AUTHOR(DRIVER_AUTHOR);
1071 MODULE_DESCRIPTION(DRIVER_DESC);
1072 #ifdef MODULE_LICENSE
1073 MODULE_LICENSE("GPL");
1074 #endif