USB: Fix a bug on appledisplay.c regarding signedness
[linux-2.6.git] / 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 __func__
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 __func__
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 mutex            lock;           /* 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 static char *legousbtower_devnode(struct device *dev, mode_t *mode)
270 {
271         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
272 }
273
274 /*
275  * usb class driver info in order to get a minor number from the usb core,
276  * and to have the device registered with the driver core
277  */
278 static struct usb_class_driver tower_class = {
279         .name =         "legousbtower%d",
280         .devnode =      legousbtower_devnode,
281         .fops =         &tower_fops,
282         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
283 };
284
285
286 /* usb specific object needed to register this driver with the usb subsystem */
287 static struct usb_driver tower_driver = {
288         .name =         "legousbtower",
289         .probe =        tower_probe,
290         .disconnect =   tower_disconnect,
291         .id_table =     tower_table,
292 };
293
294
295 /**
296  *      lego_usb_tower_debug_data
297  */
298 static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
299 {
300         int i;
301
302         if (debug < level)
303                 return;
304
305         printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
306         for (i = 0; i < size; ++i) {
307                 printk ("%.2x ", data[i]);
308         }
309         printk ("\n");
310 }
311
312
313 /**
314  *      tower_delete
315  */
316 static inline void tower_delete (struct lego_usb_tower *dev)
317 {
318         dbg(2, "%s: enter", __func__);
319
320         tower_abort_transfers (dev);
321
322         /* free data structures */
323         usb_free_urb(dev->interrupt_in_urb);
324         usb_free_urb(dev->interrupt_out_urb);
325         kfree (dev->read_buffer);
326         kfree (dev->interrupt_in_buffer);
327         kfree (dev->interrupt_out_buffer);
328         kfree (dev);
329
330         dbg(2, "%s: leave", __func__);
331 }
332
333
334 /**
335  *      tower_open
336  */
337 static int tower_open (struct inode *inode, struct file *file)
338 {
339         struct lego_usb_tower *dev = NULL;
340         int subminor;
341         int retval = 0;
342         struct usb_interface *interface;
343         struct tower_reset_reply reset_reply;
344         int result;
345
346         dbg(2, "%s: enter", __func__);
347
348         nonseekable_open(inode, file);
349         subminor = iminor(inode);
350
351         interface = usb_find_interface (&tower_driver, subminor);
352
353         if (!interface) {
354                 err ("%s - error, can't find device for minor %d",
355                      __func__, subminor);
356                 retval = -ENODEV;
357                 goto exit;
358         }
359
360         mutex_lock(&open_disc_mutex);
361         dev = usb_get_intfdata(interface);
362
363         if (!dev) {
364                 mutex_unlock(&open_disc_mutex);
365                 retval = -ENODEV;
366                 goto exit;
367         }
368
369         /* lock this device */
370         if (mutex_lock_interruptible(&dev->lock)) {
371                 mutex_unlock(&open_disc_mutex);
372                 retval = -ERESTARTSYS;
373                 goto exit;
374         }
375
376
377         /* allow opening only once */
378         if (dev->open_count) {
379                 mutex_unlock(&open_disc_mutex);
380                 retval = -EBUSY;
381                 goto unlock_exit;
382         }
383         dev->open_count = 1;
384         mutex_unlock(&open_disc_mutex);
385
386         /* reset the tower */
387         result = usb_control_msg (dev->udev,
388                                   usb_rcvctrlpipe(dev->udev, 0),
389                                   LEGO_USB_TOWER_REQUEST_RESET,
390                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
391                                   0,
392                                   0,
393                                   &reset_reply,
394                                   sizeof(reset_reply),
395                                   1000);
396         if (result < 0) {
397                 err("LEGO USB Tower reset control request failed");
398                 retval = result;
399                 goto unlock_exit;
400         }
401
402         /* initialize in direction */
403         dev->read_buffer_length = 0;
404         dev->read_packet_length = 0;
405         usb_fill_int_urb (dev->interrupt_in_urb,
406                           dev->udev,
407                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
408                           dev->interrupt_in_buffer,
409                           le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
410                           tower_interrupt_in_callback,
411                           dev,
412                           dev->interrupt_in_interval);
413
414         dev->interrupt_in_running = 1;
415         dev->interrupt_in_done = 0;
416         mb();
417
418         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
419         if (retval) {
420                 err("Couldn't submit interrupt_in_urb %d", retval);
421                 dev->interrupt_in_running = 0;
422                 dev->open_count = 0;
423                 goto unlock_exit;
424         }
425
426         /* save device in the file's private structure */
427         file->private_data = dev;
428
429 unlock_exit:
430         mutex_unlock(&dev->lock);
431
432 exit:
433         dbg(2, "%s: leave, return value %d ", __func__, retval);
434
435         return retval;
436 }
437
438 /**
439  *      tower_release
440  */
441 static int tower_release (struct inode *inode, struct file *file)
442 {
443         struct lego_usb_tower *dev;
444         int retval = 0;
445
446         dbg(2, "%s: enter", __func__);
447
448         dev = (struct lego_usb_tower *)file->private_data;
449
450         if (dev == NULL) {
451                 dbg(1, "%s: object is NULL", __func__);
452                 retval = -ENODEV;
453                 goto exit_nolock;
454         }
455
456         mutex_lock(&open_disc_mutex);
457         if (mutex_lock_interruptible(&dev->lock)) {
458                 retval = -ERESTARTSYS;
459                 goto exit;
460         }
461
462         if (dev->open_count != 1) {
463                 dbg(1, "%s: device not opened exactly once", __func__);
464                 retval = -ENODEV;
465                 goto unlock_exit;
466         }
467         if (dev->udev == NULL) {
468                 /* the device was unplugged before the file was released */
469
470                 /* unlock here as tower_delete frees dev */
471                 mutex_unlock(&dev->lock);
472                 tower_delete (dev);
473                 goto exit;
474         }
475
476         /* wait until write transfer is finished */
477         if (dev->interrupt_out_busy) {
478                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
479         }
480         tower_abort_transfers (dev);
481         dev->open_count = 0;
482
483 unlock_exit:
484         mutex_unlock(&dev->lock);
485
486 exit:
487         mutex_unlock(&open_disc_mutex);
488 exit_nolock:
489         dbg(2, "%s: leave, return value %d", __func__, retval);
490         return retval;
491 }
492
493
494 /**
495  *      tower_abort_transfers
496  *      aborts transfers and frees associated data structures
497  */
498 static void tower_abort_transfers (struct lego_usb_tower *dev)
499 {
500         dbg(2, "%s: enter", __func__);
501
502         if (dev == NULL) {
503                 dbg(1, "%s: dev is null", __func__);
504                 goto exit;
505         }
506
507         /* shutdown transfer */
508         if (dev->interrupt_in_running) {
509                 dev->interrupt_in_running = 0;
510                 mb();
511                 if (dev->udev)
512                         usb_kill_urb (dev->interrupt_in_urb);
513         }
514         if (dev->interrupt_out_busy && dev->udev)
515                 usb_kill_urb(dev->interrupt_out_urb);
516
517 exit:
518         dbg(2, "%s: leave", __func__);
519 }
520
521
522 /**
523  *      tower_check_for_read_packet
524  *
525  *      To get correct semantics for signals and non-blocking I/O
526  *      with packetizing we pretend not to see any data in the read buffer
527  *      until it has been there unchanged for at least
528  *      dev->packet_timeout_jiffies, or until the buffer is full.
529  */
530 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
531 {
532         spin_lock_irq (&dev->read_buffer_lock);
533         if (!packet_timeout
534             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
535             || dev->read_buffer_length == read_buffer_size) {
536                 dev->read_packet_length = dev->read_buffer_length;
537         }
538         dev->interrupt_in_done = 0;
539         spin_unlock_irq (&dev->read_buffer_lock);
540 }
541
542
543 /**
544  *      tower_poll
545  */
546 static unsigned int tower_poll (struct file *file, poll_table *wait)
547 {
548         struct lego_usb_tower *dev;
549         unsigned int mask = 0;
550
551         dbg(2, "%s: enter", __func__);
552
553         dev = file->private_data;
554
555         if (!dev->udev)
556                 return POLLERR | POLLHUP;
557
558         poll_wait(file, &dev->read_wait, wait);
559         poll_wait(file, &dev->write_wait, wait);
560
561         tower_check_for_read_packet(dev);
562         if (dev->read_packet_length > 0) {
563                 mask |= POLLIN | POLLRDNORM;
564         }
565         if (!dev->interrupt_out_busy) {
566                 mask |= POLLOUT | POLLWRNORM;
567         }
568
569         dbg(2, "%s: leave, mask = %d", __func__, mask);
570
571         return mask;
572 }
573
574
575 /**
576  *      tower_llseek
577  */
578 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
579 {
580         return -ESPIPE;         /* unseekable */
581 }
582
583
584 /**
585  *      tower_read
586  */
587 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
588 {
589         struct lego_usb_tower *dev;
590         size_t bytes_to_read;
591         int i;
592         int retval = 0;
593         unsigned long timeout = 0;
594
595         dbg(2, "%s: enter, count = %Zd", __func__, count);
596
597         dev = (struct lego_usb_tower *)file->private_data;
598
599         /* lock this object */
600         if (mutex_lock_interruptible(&dev->lock)) {
601                 retval = -ERESTARTSYS;
602                 goto exit;
603         }
604
605         /* verify that the device wasn't unplugged */
606         if (dev->udev == NULL) {
607                 retval = -ENODEV;
608                 err("No device or device unplugged %d", retval);
609                 goto unlock_exit;
610         }
611
612         /* verify that we actually have some data to read */
613         if (count == 0) {
614                 dbg(1, "%s: read request of 0 bytes", __func__);
615                 goto unlock_exit;
616         }
617
618         if (read_timeout) {
619                 timeout = jiffies + read_timeout * HZ / 1000;
620         }
621
622         /* wait for data */
623         tower_check_for_read_packet (dev);
624         while (dev->read_packet_length == 0) {
625                 if (file->f_flags & O_NONBLOCK) {
626                         retval = -EAGAIN;
627                         goto unlock_exit;
628                 }
629                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
630                 if (retval < 0) {
631                         goto unlock_exit;
632                 }
633
634                 /* reset read timeout during read or write activity */
635                 if (read_timeout
636                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
637                         timeout = jiffies + read_timeout * HZ / 1000;
638                 }
639                 /* check for read timeout */
640                 if (read_timeout && time_after (jiffies, timeout)) {
641                         retval = -ETIMEDOUT;
642                         goto unlock_exit;
643                 }
644                 tower_check_for_read_packet (dev);
645         }
646
647         /* copy the data from read_buffer into userspace */
648         bytes_to_read = min(count, dev->read_packet_length);
649
650         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
651                 retval = -EFAULT;
652                 goto unlock_exit;
653         }
654
655         spin_lock_irq (&dev->read_buffer_lock);
656         dev->read_buffer_length -= bytes_to_read;
657         dev->read_packet_length -= bytes_to_read;
658         for (i=0; i<dev->read_buffer_length; i++) {
659                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
660         }
661         spin_unlock_irq (&dev->read_buffer_lock);
662
663         retval = bytes_to_read;
664
665 unlock_exit:
666         /* unlock the device */
667         mutex_unlock(&dev->lock);
668
669 exit:
670         dbg(2, "%s: leave, return value %d", __func__, retval);
671         return retval;
672 }
673
674
675 /**
676  *      tower_write
677  */
678 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
679 {
680         struct lego_usb_tower *dev;
681         size_t bytes_to_write;
682         int retval = 0;
683
684         dbg(2, "%s: enter, count = %Zd", __func__, count);
685
686         dev = (struct lego_usb_tower *)file->private_data;
687
688         /* lock this object */
689         if (mutex_lock_interruptible(&dev->lock)) {
690                 retval = -ERESTARTSYS;
691                 goto exit;
692         }
693
694         /* verify that the device wasn't unplugged */
695         if (dev->udev == NULL) {
696                 retval = -ENODEV;
697                 err("No device or device unplugged %d", retval);
698                 goto unlock_exit;
699         }
700
701         /* verify that we actually have some data to write */
702         if (count == 0) {
703                 dbg(1, "%s: write request of 0 bytes", __func__);
704                 goto unlock_exit;
705         }
706
707         /* wait until previous transfer is finished */
708         while (dev->interrupt_out_busy) {
709                 if (file->f_flags & O_NONBLOCK) {
710                         retval = -EAGAIN;
711                         goto unlock_exit;
712                 }
713                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
714                 if (retval) {
715                         goto unlock_exit;
716                 }
717         }
718
719         /* write the data into interrupt_out_buffer from userspace */
720         bytes_to_write = min_t(int, count, write_buffer_size);
721         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __func__, count, bytes_to_write);
722
723         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
724                 retval = -EFAULT;
725                 goto unlock_exit;
726         }
727
728         /* send off the urb */
729         usb_fill_int_urb(dev->interrupt_out_urb,
730                          dev->udev,
731                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
732                          dev->interrupt_out_buffer,
733                          bytes_to_write,
734                          tower_interrupt_out_callback,
735                          dev,
736                          dev->interrupt_out_interval);
737
738         dev->interrupt_out_busy = 1;
739         wmb();
740
741         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
742         if (retval) {
743                 dev->interrupt_out_busy = 0;
744                 err("Couldn't submit interrupt_out_urb %d", retval);
745                 goto unlock_exit;
746         }
747         retval = bytes_to_write;
748
749 unlock_exit:
750         /* unlock the device */
751         mutex_unlock(&dev->lock);
752
753 exit:
754         dbg(2, "%s: leave, return value %d", __func__, retval);
755
756         return retval;
757 }
758
759
760 /**
761  *      tower_interrupt_in_callback
762  */
763 static void tower_interrupt_in_callback (struct urb *urb)
764 {
765         struct lego_usb_tower *dev = urb->context;
766         int status = urb->status;
767         int retval;
768
769         dbg(4, "%s: enter, status %d", __func__, status);
770
771         lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
772
773         if (status) {
774                 if (status == -ENOENT ||
775                     status == -ECONNRESET ||
776                     status == -ESHUTDOWN) {
777                         goto exit;
778                 } else {
779                         dbg(1, "%s: nonzero status received: %d", __func__, status);
780                         goto resubmit; /* maybe we can recover */
781                 }
782         }
783
784         if (urb->actual_length > 0) {
785                 spin_lock (&dev->read_buffer_lock);
786                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
787                         memcpy (dev->read_buffer + dev->read_buffer_length,
788                                 dev->interrupt_in_buffer,
789                                 urb->actual_length);
790                         dev->read_buffer_length += urb->actual_length;
791                         dev->read_last_arrival = jiffies;
792                         dbg(3, "%s: received %d bytes", __func__, urb->actual_length);
793                 } else {
794                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __func__, urb->actual_length);
795                 }
796                 spin_unlock (&dev->read_buffer_lock);
797         }
798
799 resubmit:
800         /* resubmit if we're still running */
801         if (dev->interrupt_in_running && dev->udev) {
802                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
803                 if (retval) {
804                         err("%s: usb_submit_urb failed (%d)", __func__, retval);
805                 }
806         }
807
808 exit:
809         dev->interrupt_in_done = 1;
810         wake_up_interruptible (&dev->read_wait);
811
812         lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
813         dbg(4, "%s: leave, status %d", __func__, status);
814 }
815
816
817 /**
818  *      tower_interrupt_out_callback
819  */
820 static void tower_interrupt_out_callback (struct urb *urb)
821 {
822         struct lego_usb_tower *dev = urb->context;
823         int status = urb->status;
824
825         dbg(4, "%s: enter, status %d", __func__, status);
826         lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
827
828         /* sync/async unlink faults aren't errors */
829         if (status && !(status == -ENOENT ||
830                         status == -ECONNRESET ||
831                         status == -ESHUTDOWN)) {
832                 dbg(1, "%s - nonzero write bulk status received: %d",
833                     __func__, status);
834         }
835
836         dev->interrupt_out_busy = 0;
837         wake_up_interruptible(&dev->write_wait);
838
839         lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
840         dbg(4, "%s: leave, status %d", __func__, status);
841 }
842
843
844 /**
845  *      tower_probe
846  *
847  *      Called by the usb core when a new device is connected that it thinks
848  *      this driver might be interested in.
849  */
850 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
851 {
852         struct usb_device *udev = interface_to_usbdev(interface);
853         struct lego_usb_tower *dev = NULL;
854         struct usb_host_interface *iface_desc;
855         struct usb_endpoint_descriptor* endpoint;
856         struct tower_get_version_reply get_version_reply;
857         int i;
858         int retval = -ENOMEM;
859         int result;
860
861         dbg(2, "%s: enter", __func__);
862
863         if (udev == NULL)
864                 dev_info(&interface->dev, "udev is NULL.\n");
865
866         /* allocate memory for our device state and initialize it */
867
868         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
869
870         if (dev == NULL) {
871                 err ("Out of memory");
872                 goto exit;
873         }
874
875         mutex_init(&dev->lock);
876
877         dev->udev = udev;
878         dev->open_count = 0;
879
880         dev->read_buffer = NULL;
881         dev->read_buffer_length = 0;
882         dev->read_packet_length = 0;
883         spin_lock_init (&dev->read_buffer_lock);
884         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
885         dev->read_last_arrival = jiffies;
886
887         init_waitqueue_head (&dev->read_wait);
888         init_waitqueue_head (&dev->write_wait);
889
890         dev->interrupt_in_buffer = NULL;
891         dev->interrupt_in_endpoint = NULL;
892         dev->interrupt_in_urb = NULL;
893         dev->interrupt_in_running = 0;
894         dev->interrupt_in_done = 0;
895
896         dev->interrupt_out_buffer = NULL;
897         dev->interrupt_out_endpoint = NULL;
898         dev->interrupt_out_urb = NULL;
899         dev->interrupt_out_busy = 0;
900
901         iface_desc = interface->cur_altsetting;
902
903         /* set up the endpoint information */
904         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
905                 endpoint = &iface_desc->endpoint[i].desc;
906
907                 if (usb_endpoint_xfer_int(endpoint)) {
908                         if (usb_endpoint_dir_in(endpoint))
909                                 dev->interrupt_in_endpoint = endpoint;
910                         else
911                                 dev->interrupt_out_endpoint = endpoint;
912                 }
913         }
914         if(dev->interrupt_in_endpoint == NULL) {
915                 err("interrupt in endpoint not found");
916                 goto error;
917         }
918         if (dev->interrupt_out_endpoint == NULL) {
919                 err("interrupt out endpoint not found");
920                 goto error;
921         }
922
923         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
924         if (!dev->read_buffer) {
925                 err("Couldn't allocate read_buffer");
926                 goto error;
927         }
928         dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
929         if (!dev->interrupt_in_buffer) {
930                 err("Couldn't allocate interrupt_in_buffer");
931                 goto error;
932         }
933         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
934         if (!dev->interrupt_in_urb) {
935                 err("Couldn't allocate interrupt_in_urb");
936                 goto error;
937         }
938         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
939         if (!dev->interrupt_out_buffer) {
940                 err("Couldn't allocate interrupt_out_buffer");
941                 goto error;
942         }
943         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
944         if (!dev->interrupt_out_urb) {
945                 err("Couldn't allocate interrupt_out_urb");
946                 goto error;
947         }
948         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
949         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
950
951         /* we can register the device now, as it is ready */
952         usb_set_intfdata (interface, dev);
953
954         retval = usb_register_dev (interface, &tower_class);
955
956         if (retval) {
957                 /* something prevented us from registering this driver */
958                 err ("Not able to get a minor for this device.");
959                 usb_set_intfdata (interface, NULL);
960                 goto error;
961         }
962         dev->minor = interface->minor;
963
964         /* let the user know what node this device is now attached to */
965         dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
966                  "%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
967                  USB_MAJOR, dev->minor);
968
969         /* get the firmware version and log it */
970         result = usb_control_msg (udev,
971                                   usb_rcvctrlpipe(udev, 0),
972                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
973                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
974                                   0,
975                                   0,
976                                   &get_version_reply,
977                                   sizeof(get_version_reply),
978                                   1000);
979         if (result < 0) {
980                 err("LEGO USB Tower get version control request failed");
981                 retval = result;
982                 goto error;
983         }
984         dev_info(&interface->dev, "LEGO USB Tower firmware version is %d.%d "
985                  "build %d\n", get_version_reply.major,
986                  get_version_reply.minor,
987                  le16_to_cpu(get_version_reply.build_no));
988
989
990 exit:
991         dbg(2, "%s: leave, return value 0x%.8lx (dev)", __func__, (long) dev);
992
993         return retval;
994
995 error:
996         tower_delete(dev);
997         return retval;
998 }
999
1000
1001 /**
1002  *      tower_disconnect
1003  *
1004  *      Called by the usb core when the device is removed from the system.
1005  */
1006 static void tower_disconnect (struct usb_interface *interface)
1007 {
1008         struct lego_usb_tower *dev;
1009         int minor;
1010
1011         dbg(2, "%s: enter", __func__);
1012
1013         dev = usb_get_intfdata (interface);
1014         mutex_lock(&open_disc_mutex);
1015         usb_set_intfdata (interface, NULL);
1016
1017         minor = dev->minor;
1018
1019         /* give back our minor */
1020         usb_deregister_dev (interface, &tower_class);
1021
1022         mutex_lock(&dev->lock);
1023         mutex_unlock(&open_disc_mutex);
1024
1025         /* if the device is not opened, then we clean up right now */
1026         if (!dev->open_count) {
1027                 mutex_unlock(&dev->lock);
1028                 tower_delete (dev);
1029         } else {
1030                 dev->udev = NULL;
1031                 /* wake up pollers */
1032                 wake_up_interruptible_all(&dev->read_wait);
1033                 wake_up_interruptible_all(&dev->write_wait);
1034                 mutex_unlock(&dev->lock);
1035         }
1036
1037         dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
1038                  (minor - LEGO_USB_TOWER_MINOR_BASE));
1039
1040         dbg(2, "%s: leave", __func__);
1041 }
1042
1043
1044
1045 /**
1046  *      lego_usb_tower_init
1047  */
1048 static int __init lego_usb_tower_init(void)
1049 {
1050         int result;
1051         int retval = 0;
1052
1053         dbg(2, "%s: enter", __func__);
1054
1055         /* register this driver with the USB subsystem */
1056         result = usb_register(&tower_driver);
1057         if (result < 0) {
1058                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1059                 retval = -1;
1060                 goto exit;
1061         }
1062
1063         printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
1064                DRIVER_DESC "\n");
1065
1066 exit:
1067         dbg(2, "%s: leave, return value %d", __func__, retval);
1068
1069         return retval;
1070 }
1071
1072
1073 /**
1074  *      lego_usb_tower_exit
1075  */
1076 static void __exit lego_usb_tower_exit(void)
1077 {
1078         dbg(2, "%s: enter", __func__);
1079
1080         /* deregister this driver with the USB subsystem */
1081         usb_deregister (&tower_driver);
1082
1083         dbg(2, "%s: leave", __func__);
1084 }
1085
1086 module_init (lego_usb_tower_init);
1087 module_exit (lego_usb_tower_exit);
1088
1089 MODULE_AUTHOR(DRIVER_AUTHOR);
1090 MODULE_DESCRIPTION(DRIVER_DESC);
1091 #ifdef MODULE_LICENSE
1092 MODULE_LICENSE("GPL");
1093 #endif