Merge by hand (conflicts in scsi_lib.c)
[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/config.h>
79 #include <linux/kernel.h>
80 #include <linux/errno.h>
81 #include <linux/init.h>
82 #include <linux/slab.h>
83 #include <linux/module.h>
84 #include <linux/smp_lock.h>
85 #include <linux/completion.h>
86 #include <asm/uaccess.h>
87 #include <linux/usb.h>
88 #include <linux/poll.h>
89
90
91 #ifdef CONFIG_USB_DEBUG
92         static int debug = 4;
93 #else
94         static int debug = 0;
95 #endif
96
97 /* Use our own dbg macro */
98 #undef dbg
99 #define dbg(lvl, format, arg...) do { if (debug >= lvl) printk(KERN_DEBUG  __FILE__ ": " format "\n", ## arg); } while (0)
100
101
102 /* Version Information */
103 #define DRIVER_VERSION "v0.96"
104 #define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
105 #define DRIVER_DESC "LEGO USB Tower Driver"
106
107 /* Module parameters */
108 module_param(debug, int, S_IRUGO | S_IWUSR);
109 MODULE_PARM_DESC(debug, "Debug enabled or not");
110
111 /* The defaults are chosen to work with the latest versions of leJOS and NQC.
112  */
113
114 /* Some legacy software likes to receive packets in one piece.
115  * In this case read_buffer_size should exceed the maximal packet length
116  * (417 for datalog uploads), and packet_timeout should be set.
117  */
118 static int read_buffer_size = 480;
119 module_param(read_buffer_size, int, 0);
120 MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
121
122 /* Some legacy software likes to send packets in one piece.
123  * In this case write_buffer_size should exceed the maximal packet length
124  * (417 for firmware and program downloads).
125  * A problem with long writes is that the following read may time out
126  * if the software is not prepared to wait long enough.
127  */
128 static int write_buffer_size = 480;
129 module_param(write_buffer_size, int, 0);
130 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
131
132 /* Some legacy software expects reads to contain whole LASM packets.
133  * To achieve this, characters which arrive before a packet timeout
134  * occurs will be returned in a single read operation.
135  * A problem with long reads is that the software may time out
136  * if it is not prepared to wait long enough.
137  * The packet timeout should be greater than the time between the
138  * reception of subsequent characters, which should arrive about
139  * every 5ms for the standard 2400 baud.
140  * Set it to 0 to disable.
141  */
142 static int packet_timeout = 50;
143 module_param(packet_timeout, int, 0);
144 MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
145
146 /* Some legacy software expects blocking reads to time out.
147  * Timeout occurs after the specified time of read and write inactivity.
148  * Set it to 0 to disable.
149  */
150 static int read_timeout = 200;
151 module_param(read_timeout, int, 0);
152 MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
153
154 /* As of kernel version 2.6.4 ehci-hcd uses an
155  * "only one interrupt transfer per frame" shortcut
156  * to simplify the scheduling of periodic transfers.
157  * This conflicts with our standard 1ms intervals for in and out URBs.
158  * We use default intervals of 2ms for in and 8ms for out transfers,
159  * which is fast enough for 2400 baud and allows a small additional load.
160  * Increase the interval to allow more devices that do interrupt transfers,
161  * or set to 0 to use the standard interval from the endpoint descriptors.
162  */
163 static int interrupt_in_interval = 2;
164 module_param(interrupt_in_interval, int, 0);
165 MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
166
167 static int interrupt_out_interval = 8;
168 module_param(interrupt_out_interval, int, 0);
169 MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
170
171 /* Define these values to match your device */
172 #define LEGO_USB_TOWER_VENDOR_ID        0x0694
173 #define LEGO_USB_TOWER_PRODUCT_ID       0x0001
174
175 /* Vendor requests */
176 #define LEGO_USB_TOWER_REQUEST_RESET            0x04
177 #define LEGO_USB_TOWER_REQUEST_GET_VERSION      0xFD
178
179 struct tower_reset_reply {
180         __le16 size;            /* little-endian */
181         __u8 err_code;
182         __u8 spare;
183 } __attribute__ ((packed));
184
185 struct tower_get_version_reply {
186         __le16 size;            /* little-endian */
187         __u8 err_code;
188         __u8 spare;
189         __u8 major;
190         __u8 minor;
191         __le16 build_no;                /* little-endian */
192 } __attribute__ ((packed));
193
194
195 /* table of devices that work with this driver */
196 static struct usb_device_id tower_table [] = {
197         { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
198         { }                                     /* Terminating entry */
199 };
200
201 MODULE_DEVICE_TABLE (usb, tower_table);
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, struct pt_regs *regs);
252 static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs);
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 /* prevent races between open() and disconnect */
259 static DECLARE_MUTEX (disconnect_sem);
260
261 /* file operations needed when we register this driver */
262 static struct file_operations tower_fops = {
263         .owner =        THIS_MODULE,
264         .read  =        tower_read,
265         .write =        tower_write,
266         .open =         tower_open,
267         .release =      tower_release,
268         .poll =         tower_poll,
269         .llseek =       tower_llseek,
270 };
271
272 /*
273  * usb class driver info in order to get a minor number from the usb core,
274  * and to have the device registered with the driver core
275  */
276 static struct usb_class_driver tower_class = {
277         .name =         "legousbtower%d",
278         .fops =         &tower_fops,
279         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
280 };
281
282
283 /* usb specific object needed to register this driver with the usb subsystem */
284 static struct usb_driver tower_driver = {
285         .owner =        THIS_MODULE,
286         .name =         "legousbtower",
287         .probe =        tower_probe,
288         .disconnect =   tower_disconnect,
289         .id_table =     tower_table,
290 };
291
292
293 /**
294  *      lego_usb_tower_debug_data
295  */
296 static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
297 {
298         int i;
299
300         if (debug < level)
301                 return;
302
303         printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
304         for (i = 0; i < size; ++i) {
305                 printk ("%.2x ", data[i]);
306         }
307         printk ("\n");
308 }
309
310
311 /**
312  *      tower_delete
313  */
314 static inline void tower_delete (struct lego_usb_tower *dev)
315 {
316         dbg(2, "%s: enter", __FUNCTION__);
317
318         tower_abort_transfers (dev);
319
320         /* free data structures */
321         if (dev->interrupt_in_urb != NULL) {
322                 usb_free_urb (dev->interrupt_in_urb);
323         }
324         if (dev->interrupt_out_urb != NULL) {
325                 usb_free_urb (dev->interrupt_out_urb);
326         }
327         kfree (dev->read_buffer);
328         kfree (dev->interrupt_in_buffer);
329         kfree (dev->interrupt_out_buffer);
330         kfree (dev);
331
332         dbg(2, "%s: leave", __FUNCTION__);
333 }
334
335
336 /**
337  *      tower_open
338  */
339 static int tower_open (struct inode *inode, struct file *file)
340 {
341         struct lego_usb_tower *dev = NULL;
342         int subminor;
343         int retval = 0;
344         struct usb_interface *interface;
345         struct tower_reset_reply reset_reply;
346         int result;
347
348         dbg(2, "%s: enter", __FUNCTION__);
349
350         nonseekable_open(inode, file);
351         subminor = iminor(inode);
352
353         down (&disconnect_sem);
354
355         interface = usb_find_interface (&tower_driver, subminor);
356
357         if (!interface) {
358                 err ("%s - error, can't find device for minor %d",
359                      __FUNCTION__, subminor);
360                 retval = -ENODEV;
361                 goto unlock_disconnect_exit;
362         }
363
364         dev = usb_get_intfdata(interface);
365
366         if (!dev) {
367                 retval = -ENODEV;
368                 goto unlock_disconnect_exit;
369         }
370
371         /* lock this device */
372         if (down_interruptible (&dev->sem)) {
373                 retval = -ERESTARTSYS;
374                 goto unlock_disconnect_exit;
375         }
376
377         /* allow opening only once */
378         if (dev->open_count) {
379                 retval = -EBUSY;
380                 goto unlock_exit;
381         }
382         dev->open_count = 1;
383
384         /* reset the tower */
385         result = usb_control_msg (dev->udev,
386                                   usb_rcvctrlpipe(dev->udev, 0),
387                                   LEGO_USB_TOWER_REQUEST_RESET,
388                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
389                                   0,
390                                   0,
391                                   &reset_reply,
392                                   sizeof(reset_reply),
393                                   1000);
394         if (result < 0) {
395                 err("LEGO USB Tower reset control request failed");
396                 retval = result;
397                 goto unlock_exit;
398         }
399
400         /* initialize in direction */
401         dev->read_buffer_length = 0;
402         dev->read_packet_length = 0;
403         usb_fill_int_urb (dev->interrupt_in_urb,
404                           dev->udev,
405                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
406                           dev->interrupt_in_buffer,
407                           le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
408                           tower_interrupt_in_callback,
409                           dev,
410                           dev->interrupt_in_interval);
411
412         dev->interrupt_in_running = 1;
413         dev->interrupt_in_done = 0;
414         mb();
415
416         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
417         if (retval) {
418                 err("Couldn't submit interrupt_in_urb %d", retval);
419                 dev->interrupt_in_running = 0;
420                 dev->open_count = 0;
421                 goto unlock_exit;
422         }
423
424         /* save device in the file's private structure */
425         file->private_data = dev;
426
427 unlock_exit:
428         up (&dev->sem);
429
430 unlock_disconnect_exit:
431         up (&disconnect_sem);
432
433         dbg(2, "%s: leave, return value %d ", __FUNCTION__, 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", __FUNCTION__);
447
448         dev = (struct lego_usb_tower *)file->private_data;
449
450         if (dev == NULL) {
451                 dbg(1, "%s: object is NULL", __FUNCTION__);
452                 retval = -ENODEV;
453                 goto exit;
454         }
455
456         if (down_interruptible (&dev->sem)) {
457                 retval = -ERESTARTSYS;
458                 goto exit;
459         }
460
461         if (dev->open_count != 1) {
462                 dbg(1, "%s: device not opened exactly once", __FUNCTION__);
463                 retval = -ENODEV;
464                 goto unlock_exit;
465         }
466         if (dev->udev == NULL) {
467                 /* the device was unplugged before the file was released */
468                 up (&dev->sem); /* unlock here as tower_delete frees dev */
469                 tower_delete (dev);
470                 goto exit;
471         }
472
473         /* wait until write transfer is finished */
474         if (dev->interrupt_out_busy) {
475                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
476         }
477         tower_abort_transfers (dev);
478         dev->open_count = 0;
479
480 unlock_exit:
481         up (&dev->sem);
482
483 exit:
484         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
485         return retval;
486 }
487
488
489 /**
490  *      tower_abort_transfers
491  *      aborts transfers and frees associated data structures
492  */
493 static void tower_abort_transfers (struct lego_usb_tower *dev)
494 {
495         dbg(2, "%s: enter", __FUNCTION__);
496
497         if (dev == NULL) {
498                 dbg(1, "%s: dev is null", __FUNCTION__);
499                 goto exit;
500         }
501
502         /* shutdown transfer */
503         if (dev->interrupt_in_running) {
504                 dev->interrupt_in_running = 0;
505                 mb();
506                 if (dev->interrupt_in_urb != NULL && dev->udev) {
507                         usb_kill_urb (dev->interrupt_in_urb);
508                 }
509         }
510         if (dev->interrupt_out_busy) {
511                 if (dev->interrupt_out_urb != NULL && dev->udev) {
512                         usb_kill_urb (dev->interrupt_out_urb);
513                 }
514         }
515
516 exit:
517         dbg(2, "%s: leave", __FUNCTION__);
518 }
519
520
521 /**
522  *      tower_check_for_read_packet
523  *
524  *      To get correct semantics for signals and non-blocking I/O
525  *      with packetizing we pretend not to see any data in the read buffer
526  *      until it has been there unchanged for at least
527  *      dev->packet_timeout_jiffies, or until the buffer is full.
528  */
529 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
530 {
531         spin_lock_irq (&dev->read_buffer_lock);
532         if (!packet_timeout
533             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
534             || dev->read_buffer_length == read_buffer_size) {
535                 dev->read_packet_length = dev->read_buffer_length;
536         }
537         dev->interrupt_in_done = 0;
538         spin_unlock_irq (&dev->read_buffer_lock);
539 }
540
541
542 /**
543  *      tower_poll
544  */
545 static unsigned int tower_poll (struct file *file, poll_table *wait)
546 {
547         struct lego_usb_tower *dev;
548         unsigned int mask = 0;
549
550         dbg(2, "%s: enter", __FUNCTION__);
551
552         dev = file->private_data;
553
554         poll_wait(file, &dev->read_wait, wait);
555         poll_wait(file, &dev->write_wait, wait);
556
557         tower_check_for_read_packet(dev);
558         if (dev->read_packet_length > 0) {
559                 mask |= POLLIN | POLLRDNORM;
560         }
561         if (!dev->interrupt_out_busy) {
562                 mask |= POLLOUT | POLLWRNORM;
563         }
564
565         dbg(2, "%s: leave, mask = %d", __FUNCTION__, mask);
566
567         return mask;
568 }
569
570
571 /**
572  *      tower_llseek
573  */
574 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
575 {
576         return -ESPIPE;         /* unseekable */
577 }
578
579
580 /**
581  *      tower_read
582  */
583 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
584 {
585         struct lego_usb_tower *dev;
586         size_t bytes_to_read;
587         int i;
588         int retval = 0;
589         unsigned long timeout = 0;
590
591         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
592
593         dev = (struct lego_usb_tower *)file->private_data;
594
595         /* lock this object */
596         if (down_interruptible (&dev->sem)) {
597                 retval = -ERESTARTSYS;
598                 goto exit;
599         }
600
601         /* verify that the device wasn't unplugged */
602         if (dev->udev == NULL) {
603                 retval = -ENODEV;
604                 err("No device or device unplugged %d", retval);
605                 goto unlock_exit;
606         }
607
608         /* verify that we actually have some data to read */
609         if (count == 0) {
610                 dbg(1, "%s: read request of 0 bytes", __FUNCTION__);
611                 goto unlock_exit;
612         }
613
614         if (read_timeout) {
615                 timeout = jiffies + read_timeout * HZ / 1000;
616         }
617
618         /* wait for data */
619         tower_check_for_read_packet (dev);
620         while (dev->read_packet_length == 0) {
621                 if (file->f_flags & O_NONBLOCK) {
622                         retval = -EAGAIN;
623                         goto unlock_exit;
624                 }
625                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
626                 if (retval < 0) {
627                         goto unlock_exit;
628                 }
629
630                 /* reset read timeout during read or write activity */
631                 if (read_timeout
632                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
633                         timeout = jiffies + read_timeout * HZ / 1000;
634                 }
635                 /* check for read timeout */
636                 if (read_timeout && time_after (jiffies, timeout)) {
637                         retval = -ETIMEDOUT;
638                         goto unlock_exit;
639                 }
640                 tower_check_for_read_packet (dev);
641         }
642
643         /* copy the data from read_buffer into userspace */
644         bytes_to_read = min(count, dev->read_packet_length);
645
646         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
647                 retval = -EFAULT;
648                 goto unlock_exit;
649         }
650
651         spin_lock_irq (&dev->read_buffer_lock);
652         dev->read_buffer_length -= bytes_to_read;
653         dev->read_packet_length -= bytes_to_read;
654         for (i=0; i<dev->read_buffer_length; i++) {
655                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
656         }
657         spin_unlock_irq (&dev->read_buffer_lock);
658
659         retval = bytes_to_read;
660
661 unlock_exit:
662         /* unlock the device */
663         up (&dev->sem);
664
665 exit:
666         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
667         return retval;
668 }
669
670
671 /**
672  *      tower_write
673  */
674 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
675 {
676         struct lego_usb_tower *dev;
677         size_t bytes_to_write;
678         int retval = 0;
679
680         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
681
682         dev = (struct lego_usb_tower *)file->private_data;
683
684         /* lock this object */
685         if (down_interruptible (&dev->sem)) {
686                 retval = -ERESTARTSYS;
687                 goto exit;
688         }
689
690         /* verify that the device wasn't unplugged */
691         if (dev->udev == NULL) {
692                 retval = -ENODEV;
693                 err("No device or device unplugged %d", retval);
694                 goto unlock_exit;
695         }
696
697         /* verify that we actually have some data to write */
698         if (count == 0) {
699                 dbg(1, "%s: write request of 0 bytes", __FUNCTION__);
700                 goto unlock_exit;
701         }
702
703         /* wait until previous transfer is finished */
704         while (dev->interrupt_out_busy) {
705                 if (file->f_flags & O_NONBLOCK) {
706                         retval = -EAGAIN;
707                         goto unlock_exit;
708                 }
709                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
710                 if (retval) {
711                         goto unlock_exit;
712                 }
713         }
714
715         /* write the data into interrupt_out_buffer from userspace */
716         bytes_to_write = min_t(int, count, write_buffer_size);
717         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __FUNCTION__, count, bytes_to_write);
718
719         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
720                 retval = -EFAULT;
721                 goto unlock_exit;
722         }
723
724         /* send off the urb */
725         usb_fill_int_urb(dev->interrupt_out_urb,
726                          dev->udev,
727                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
728                          dev->interrupt_out_buffer,
729                          bytes_to_write,
730                          tower_interrupt_out_callback,
731                          dev,
732                          dev->interrupt_out_interval);
733
734         dev->interrupt_out_busy = 1;
735         wmb();
736
737         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
738         if (retval) {
739                 dev->interrupt_out_busy = 0;
740                 err("Couldn't submit interrupt_out_urb %d", retval);
741                 goto unlock_exit;
742         }
743         retval = bytes_to_write;
744
745 unlock_exit:
746         /* unlock the device */
747         up (&dev->sem);
748
749 exit:
750         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
751
752         return retval;
753 }
754
755
756 /**
757  *      tower_interrupt_in_callback
758  */
759 static void tower_interrupt_in_callback (struct urb *urb, struct pt_regs *regs)
760 {
761         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
762         int retval;
763
764         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
765
766         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
767
768         if (urb->status) {
769                 if (urb->status == -ENOENT ||
770                     urb->status == -ECONNRESET ||
771                     urb->status == -ESHUTDOWN) {
772                         goto exit;
773                 } else {
774                         dbg(1, "%s: nonzero status received: %d", __FUNCTION__, urb->status);
775                         goto resubmit; /* maybe we can recover */
776                 }
777         }
778
779         if (urb->actual_length > 0) {
780                 spin_lock (&dev->read_buffer_lock);
781                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
782                         memcpy (dev->read_buffer + dev->read_buffer_length,
783                                 dev->interrupt_in_buffer,
784                                 urb->actual_length);
785                         dev->read_buffer_length += urb->actual_length;
786                         dev->read_last_arrival = jiffies;
787                         dbg(3, "%s: received %d bytes", __FUNCTION__, urb->actual_length);
788                 } else {
789                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __FUNCTION__, urb->actual_length);
790                 }
791                 spin_unlock (&dev->read_buffer_lock);
792         }
793
794 resubmit:
795         /* resubmit if we're still running */
796         if (dev->interrupt_in_running && dev->udev) {
797                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
798                 if (retval) {
799                         err("%s: usb_submit_urb failed (%d)", __FUNCTION__, retval);
800                 }
801         }
802
803 exit:
804         dev->interrupt_in_done = 1;
805         wake_up_interruptible (&dev->read_wait);
806
807         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
808         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
809 }
810
811
812 /**
813  *      tower_interrupt_out_callback
814  */
815 static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs)
816 {
817         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
818
819         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
820         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
821
822         /* sync/async unlink faults aren't errors */
823         if (urb->status && !(urb->status == -ENOENT ||
824                              urb->status == -ECONNRESET ||
825                              urb->status == -ESHUTDOWN)) {
826                 dbg(1, "%s - nonzero write bulk status received: %d",
827                     __FUNCTION__, urb->status);
828         }
829
830         dev->interrupt_out_busy = 0;
831         wake_up_interruptible(&dev->write_wait);
832
833         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
834         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
835 }
836
837
838 /**
839  *      tower_probe
840  *
841  *      Called by the usb core when a new device is connected that it thinks
842  *      this driver might be interested in.
843  */
844 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
845 {
846         struct usb_device *udev = interface_to_usbdev(interface);
847         struct lego_usb_tower *dev = NULL;
848         struct usb_host_interface *iface_desc;
849         struct usb_endpoint_descriptor* endpoint;
850         struct tower_get_version_reply get_version_reply;
851         int i;
852         int retval = -ENOMEM;
853         int result;
854
855         dbg(2, "%s: enter", __FUNCTION__);
856
857         if (udev == NULL) {
858                 info ("udev is NULL.");
859         }
860
861         /* allocate memory for our device state and initialize it */
862
863         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
864
865         if (dev == NULL) {
866                 err ("Out of memory");
867                 goto exit;
868         }
869
870         init_MUTEX (&dev->sem);
871
872         dev->udev = udev;
873         dev->open_count = 0;
874
875         dev->read_buffer = NULL;
876         dev->read_buffer_length = 0;
877         dev->read_packet_length = 0;
878         spin_lock_init (&dev->read_buffer_lock);
879         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
880         dev->read_last_arrival = jiffies;
881
882         init_waitqueue_head (&dev->read_wait);
883         init_waitqueue_head (&dev->write_wait);
884
885         dev->interrupt_in_buffer = NULL;
886         dev->interrupt_in_endpoint = NULL;
887         dev->interrupt_in_urb = NULL;
888         dev->interrupt_in_running = 0;
889         dev->interrupt_in_done = 0;
890
891         dev->interrupt_out_buffer = NULL;
892         dev->interrupt_out_endpoint = NULL;
893         dev->interrupt_out_urb = NULL;
894         dev->interrupt_out_busy = 0;
895
896         iface_desc = interface->cur_altsetting;
897
898         /* set up the endpoint information */
899         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
900                 endpoint = &iface_desc->endpoint[i].desc;
901
902                 if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN) &&
903                     ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
904                         dev->interrupt_in_endpoint = endpoint;
905                 }
906
907                 if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT) &&
908                     ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
909                         dev->interrupt_out_endpoint = endpoint;
910                 }
911         }
912         if(dev->interrupt_in_endpoint == NULL) {
913                 err("interrupt in endpoint not found");
914                 goto error;
915         }
916         if (dev->interrupt_out_endpoint == NULL) {
917                 err("interrupt out endpoint not found");
918                 goto error;
919         }
920
921         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
922         if (!dev->read_buffer) {
923                 err("Couldn't allocate read_buffer");
924                 goto error;
925         }
926         dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
927         if (!dev->interrupt_in_buffer) {
928                 err("Couldn't allocate interrupt_in_buffer");
929                 goto error;
930         }
931         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
932         if (!dev->interrupt_in_urb) {
933                 err("Couldn't allocate interrupt_in_urb");
934                 goto error;
935         }
936         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
937         if (!dev->interrupt_out_buffer) {
938                 err("Couldn't allocate interrupt_out_buffer");
939                 goto error;
940         }
941         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
942         if (!dev->interrupt_out_urb) {
943                 err("Couldn't allocate interrupt_out_urb");
944                 goto error;
945         }
946         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
947         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
948
949         /* we can register the device now, as it is ready */
950         usb_set_intfdata (interface, dev);
951
952         retval = usb_register_dev (interface, &tower_class);
953
954         if (retval) {
955                 /* something prevented us from registering this driver */
956                 err ("Not able to get a minor for this device.");
957                 usb_set_intfdata (interface, NULL);
958                 goto error;
959         }
960         dev->minor = interface->minor;
961
962         /* let the user know what node this device is now attached to */
963         info ("LEGO USB Tower #%d now attached to major %d minor %d", (dev->minor - LEGO_USB_TOWER_MINOR_BASE), USB_MAJOR, dev->minor);
964
965         /* get the firmware version and log it */
966         result = usb_control_msg (udev,
967                                   usb_rcvctrlpipe(udev, 0),
968                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
969                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
970                                   0,
971                                   0,
972                                   &get_version_reply,
973                                   sizeof(get_version_reply),
974                                   1000);
975         if (result < 0) {
976                 err("LEGO USB Tower get version control request failed");
977                 retval = result;
978                 goto error;
979         }
980         info("LEGO USB Tower firmware version is %d.%d build %d",
981              get_version_reply.major,
982              get_version_reply.minor,
983              le16_to_cpu(get_version_reply.build_no));
984
985
986 exit:
987         dbg(2, "%s: leave, return value 0x%.8lx (dev)", __FUNCTION__, (long) dev);
988
989         return retval;
990
991 error:
992         tower_delete(dev);
993         return retval;
994 }
995
996
997 /**
998  *      tower_disconnect
999  *
1000  *      Called by the usb core when the device is removed from the system.
1001  */
1002 static void tower_disconnect (struct usb_interface *interface)
1003 {
1004         struct lego_usb_tower *dev;
1005         int minor;
1006
1007         dbg(2, "%s: enter", __FUNCTION__);
1008
1009         down (&disconnect_sem);
1010
1011         dev = usb_get_intfdata (interface);
1012         usb_set_intfdata (interface, NULL);
1013
1014
1015         down (&dev->sem);
1016
1017         minor = dev->minor;
1018
1019         /* give back our minor */
1020         usb_deregister_dev (interface, &tower_class);
1021
1022         /* if the device is not opened, then we clean up right now */
1023         if (!dev->open_count) {
1024                 up (&dev->sem);
1025                 tower_delete (dev);
1026         } else {
1027                 dev->udev = NULL;
1028                 up (&dev->sem);
1029         }
1030
1031         up (&disconnect_sem);
1032
1033         info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));
1034
1035         dbg(2, "%s: leave", __FUNCTION__);
1036 }
1037
1038
1039
1040 /**
1041  *      lego_usb_tower_init
1042  */
1043 static int __init lego_usb_tower_init(void)
1044 {
1045         int result;
1046         int retval = 0;
1047
1048         dbg(2, "%s: enter", __FUNCTION__);
1049
1050         /* register this driver with the USB subsystem */
1051         result = usb_register(&tower_driver);
1052         if (result < 0) {
1053                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1054                 retval = -1;
1055                 goto exit;
1056         }
1057
1058         info(DRIVER_DESC " " DRIVER_VERSION);
1059
1060 exit:
1061         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
1062
1063         return retval;
1064 }
1065
1066
1067 /**
1068  *      lego_usb_tower_exit
1069  */
1070 static void __exit lego_usb_tower_exit(void)
1071 {
1072         dbg(2, "%s: enter", __FUNCTION__);
1073
1074         /* deregister this driver with the USB subsystem */
1075         usb_deregister (&tower_driver);
1076
1077         dbg(2, "%s: leave", __FUNCTION__);
1078 }
1079
1080 module_init (lego_usb_tower_init);
1081 module_exit (lego_usb_tower_exit);
1082
1083 MODULE_AUTHOR(DRIVER_AUTHOR);
1084 MODULE_DESCRIPTION(DRIVER_DESC);
1085 #ifdef MODULE_LICENSE
1086 MODULE_LICENSE("GPL");
1087 #endif