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Linux/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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 79 
 80 #include <linux/kernel.h>
 81 #include <linux/errno.h>
 82 #include <linux/slab.h>
 83 #include <linux/module.h>
 84 #include <linux/completion.h>
 85 #include <linux/mutex.h>
 86 #include <asm/uaccess.h>
 87 #include <linux/usb.h>
 88 #include <linux/poll.h>
 89 
 90 
 91 /* Version Information */
 92 #define DRIVER_VERSION "v0.96"
 93 #define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
 94 #define DRIVER_DESC "LEGO USB Tower Driver"
 95 
 96 
 97 /* The defaults are chosen to work with the latest versions of leJOS and NQC.
 98  */
 99 
100 /* Some legacy software likes to receive packets in one piece.
101  * In this case read_buffer_size should exceed the maximal packet length
102  * (417 for datalog uploads), and packet_timeout should be set.
103  */
104 static int read_buffer_size = 480;
105 module_param(read_buffer_size, int, 0);
106 MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
107 
108 /* Some legacy software likes to send packets in one piece.
109  * In this case write_buffer_size should exceed the maximal packet length
110  * (417 for firmware and program downloads).
111  * A problem with long writes is that the following read may time out
112  * if the software is not prepared to wait long enough.
113  */
114 static int write_buffer_size = 480;
115 module_param(write_buffer_size, int, 0);
116 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
117 
118 /* Some legacy software expects reads to contain whole LASM packets.
119  * To achieve this, characters which arrive before a packet timeout
120  * occurs will be returned in a single read operation.
121  * A problem with long reads is that the software may time out
122  * if it is not prepared to wait long enough.
123  * The packet timeout should be greater than the time between the
124  * reception of subsequent characters, which should arrive about
125  * every 5ms for the standard 2400 baud.
126  * Set it to 0 to disable.
127  */
128 static int packet_timeout = 50;
129 module_param(packet_timeout, int, 0);
130 MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
131 
132 /* Some legacy software expects blocking reads to time out.
133  * Timeout occurs after the specified time of read and write inactivity.
134  * Set it to 0 to disable.
135  */
136 static int read_timeout = 200;
137 module_param(read_timeout, int, 0);
138 MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
139 
140 /* As of kernel version 2.6.4 ehci-hcd uses an
141  * "only one interrupt transfer per frame" shortcut
142  * to simplify the scheduling of periodic transfers.
143  * This conflicts with our standard 1ms intervals for in and out URBs.
144  * We use default intervals of 2ms for in and 8ms for out transfers,
145  * which is fast enough for 2400 baud and allows a small additional load.
146  * Increase the interval to allow more devices that do interrupt transfers,
147  * or set to 0 to use the standard interval from the endpoint descriptors.
148  */
149 static int interrupt_in_interval = 2;
150 module_param(interrupt_in_interval, int, 0);
151 MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
152 
153 static int interrupt_out_interval = 8;
154 module_param(interrupt_out_interval, int, 0);
155 MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
156 
157 /* Define these values to match your device */
158 #define LEGO_USB_TOWER_VENDOR_ID        0x0694
159 #define LEGO_USB_TOWER_PRODUCT_ID       0x0001
160 
161 /* Vendor requests */
162 #define LEGO_USB_TOWER_REQUEST_RESET            0x04
163 #define LEGO_USB_TOWER_REQUEST_GET_VERSION      0xFD
164 
165 struct tower_reset_reply {
166         __le16 size;            /* little-endian */
167         __u8 err_code;
168         __u8 spare;
169 } __attribute__ ((packed));
170 
171 struct tower_get_version_reply {
172         __le16 size;            /* little-endian */
173         __u8 err_code;
174         __u8 spare;
175         __u8 major;
176         __u8 minor;
177         __le16 build_no;                /* little-endian */
178 } __attribute__ ((packed));
179 
180 
181 /* table of devices that work with this driver */
182 static const struct usb_device_id tower_table[] = {
183         { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
184         { }                                     /* Terminating entry */
185 };
186 
187 MODULE_DEVICE_TABLE (usb, tower_table);
188 static DEFINE_MUTEX(open_disc_mutex);
189 
190 #define LEGO_USB_TOWER_MINOR_BASE       160
191 
192 
193 /* Structure to hold all of our device specific stuff */
194 struct lego_usb_tower {
195         struct mutex            lock;           /* locks this structure */
196         struct usb_device*      udev;           /* save off the usb device pointer */
197         unsigned char           minor;          /* the starting minor number for this device */
198 
199         int                     open_count;     /* number of times this port has been opened */
200 
201         char*                   read_buffer;
202         size_t                  read_buffer_length; /* this much came in */
203         size_t                  read_packet_length; /* this much will be returned on read */
204         spinlock_t              read_buffer_lock;
205         int                     packet_timeout_jiffies;
206         unsigned long           read_last_arrival;
207 
208         wait_queue_head_t       read_wait;
209         wait_queue_head_t       write_wait;
210 
211         char*                   interrupt_in_buffer;
212         struct usb_endpoint_descriptor* interrupt_in_endpoint;
213         struct urb*             interrupt_in_urb;
214         int                     interrupt_in_interval;
215         int                     interrupt_in_running;
216         int                     interrupt_in_done;
217 
218         char*                   interrupt_out_buffer;
219         struct usb_endpoint_descriptor* interrupt_out_endpoint;
220         struct urb*             interrupt_out_urb;
221         int                     interrupt_out_interval;
222         int                     interrupt_out_busy;
223 
224 };
225 
226 
227 /* local function prototypes */
228 static ssize_t tower_read       (struct file *file, char __user *buffer, size_t count, loff_t *ppos);
229 static ssize_t tower_write      (struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
230 static inline void tower_delete (struct lego_usb_tower *dev);
231 static int tower_open           (struct inode *inode, struct file *file);
232 static int tower_release        (struct inode *inode, struct file *file);
233 static unsigned int tower_poll  (struct file *file, poll_table *wait);
234 static loff_t tower_llseek      (struct file *file, loff_t off, int whence);
235 
236 static void tower_abort_transfers (struct lego_usb_tower *dev);
237 static void tower_check_for_read_packet (struct lego_usb_tower *dev);
238 static void tower_interrupt_in_callback (struct urb *urb);
239 static void tower_interrupt_out_callback (struct urb *urb);
240 
241 static int  tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
242 static void tower_disconnect    (struct usb_interface *interface);
243 
244 
245 /* file operations needed when we register this driver */
246 static const struct file_operations tower_fops = {
247         .owner =        THIS_MODULE,
248         .read  =        tower_read,
249         .write =        tower_write,
250         .open =         tower_open,
251         .release =      tower_release,
252         .poll =         tower_poll,
253         .llseek =       tower_llseek,
254 };
255 
256 static char *legousbtower_devnode(struct device *dev, umode_t *mode)
257 {
258         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
259 }
260 
261 /*
262  * usb class driver info in order to get a minor number from the usb core,
263  * and to have the device registered with the driver core
264  */
265 static struct usb_class_driver tower_class = {
266         .name =         "legousbtower%d",
267         .devnode =      legousbtower_devnode,
268         .fops =         &tower_fops,
269         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
270 };
271 
272 
273 /* usb specific object needed to register this driver with the usb subsystem */
274 static struct usb_driver tower_driver = {
275         .name =         "legousbtower",
276         .probe =        tower_probe,
277         .disconnect =   tower_disconnect,
278         .id_table =     tower_table,
279 };
280 
281 
282 /**
283  *      lego_usb_tower_debug_data
284  */
285 static inline void lego_usb_tower_debug_data(struct device *dev,
286                                              const char *function, int size,
287                                              const unsigned char *data)
288 {
289         dev_dbg(dev, "%s - length = %d, data = %*ph\n",
290                 function, size, size, data);
291 }
292 
293 
294 /**
295  *      tower_delete
296  */
297 static inline void tower_delete (struct lego_usb_tower *dev)
298 {
299         tower_abort_transfers (dev);
300 
301         /* free data structures */
302         usb_free_urb(dev->interrupt_in_urb);
303         usb_free_urb(dev->interrupt_out_urb);
304         kfree (dev->read_buffer);
305         kfree (dev->interrupt_in_buffer);
306         kfree (dev->interrupt_out_buffer);
307         kfree (dev);
308 }
309 
310 
311 /**
312  *      tower_open
313  */
314 static int tower_open (struct inode *inode, struct file *file)
315 {
316         struct lego_usb_tower *dev = NULL;
317         int subminor;
318         int retval = 0;
319         struct usb_interface *interface;
320         struct tower_reset_reply reset_reply;
321         int result;
322 
323         nonseekable_open(inode, file);
324         subminor = iminor(inode);
325 
326         interface = usb_find_interface (&tower_driver, subminor);
327 
328         if (!interface) {
329                 pr_err("error, can't find device for minor %d\n", subminor);
330                 retval = -ENODEV;
331                 goto exit;
332         }
333 
334         mutex_lock(&open_disc_mutex);
335         dev = usb_get_intfdata(interface);
336 
337         if (!dev) {
338                 mutex_unlock(&open_disc_mutex);
339                 retval = -ENODEV;
340                 goto exit;
341         }
342 
343         /* lock this device */
344         if (mutex_lock_interruptible(&dev->lock)) {
345                 mutex_unlock(&open_disc_mutex);
346                 retval = -ERESTARTSYS;
347                 goto exit;
348         }
349 
350 
351         /* allow opening only once */
352         if (dev->open_count) {
353                 mutex_unlock(&open_disc_mutex);
354                 retval = -EBUSY;
355                 goto unlock_exit;
356         }
357         dev->open_count = 1;
358         mutex_unlock(&open_disc_mutex);
359 
360         /* reset the tower */
361         result = usb_control_msg (dev->udev,
362                                   usb_rcvctrlpipe(dev->udev, 0),
363                                   LEGO_USB_TOWER_REQUEST_RESET,
364                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
365                                   0,
366                                   0,
367                                   &reset_reply,
368                                   sizeof(reset_reply),
369                                   1000);
370         if (result < 0) {
371                 dev_err(&dev->udev->dev,
372                         "LEGO USB Tower reset control request failed\n");
373                 retval = result;
374                 goto unlock_exit;
375         }
376 
377         /* initialize in direction */
378         dev->read_buffer_length = 0;
379         dev->read_packet_length = 0;
380         usb_fill_int_urb (dev->interrupt_in_urb,
381                           dev->udev,
382                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
383                           dev->interrupt_in_buffer,
384                           usb_endpoint_maxp(dev->interrupt_in_endpoint),
385                           tower_interrupt_in_callback,
386                           dev,
387                           dev->interrupt_in_interval);
388 
389         dev->interrupt_in_running = 1;
390         dev->interrupt_in_done = 0;
391         mb();
392 
393         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
394         if (retval) {
395                 dev_err(&dev->udev->dev,
396                         "Couldn't submit interrupt_in_urb %d\n", retval);
397                 dev->interrupt_in_running = 0;
398                 dev->open_count = 0;
399                 goto unlock_exit;
400         }
401 
402         /* save device in the file's private structure */
403         file->private_data = dev;
404 
405 unlock_exit:
406         mutex_unlock(&dev->lock);
407 
408 exit:
409         return retval;
410 }
411 
412 /**
413  *      tower_release
414  */
415 static int tower_release (struct inode *inode, struct file *file)
416 {
417         struct lego_usb_tower *dev;
418         int retval = 0;
419 
420         dev = file->private_data;
421 
422         if (dev == NULL) {
423                 retval = -ENODEV;
424                 goto exit_nolock;
425         }
426 
427         mutex_lock(&open_disc_mutex);
428         if (mutex_lock_interruptible(&dev->lock)) {
429                 retval = -ERESTARTSYS;
430                 goto exit;
431         }
432 
433         if (dev->open_count != 1) {
434                 dev_dbg(&dev->udev->dev, "%s: device not opened exactly once\n",
435                         __func__);
436                 retval = -ENODEV;
437                 goto unlock_exit;
438         }
439         if (dev->udev == NULL) {
440                 /* the device was unplugged before the file was released */
441 
442                 /* unlock here as tower_delete frees dev */
443                 mutex_unlock(&dev->lock);
444                 tower_delete (dev);
445                 goto exit;
446         }
447 
448         /* wait until write transfer is finished */
449         if (dev->interrupt_out_busy) {
450                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
451         }
452         tower_abort_transfers (dev);
453         dev->open_count = 0;
454 
455 unlock_exit:
456         mutex_unlock(&dev->lock);
457 
458 exit:
459         mutex_unlock(&open_disc_mutex);
460 exit_nolock:
461         return retval;
462 }
463 
464 
465 /**
466  *      tower_abort_transfers
467  *      aborts transfers and frees associated data structures
468  */
469 static void tower_abort_transfers (struct lego_usb_tower *dev)
470 {
471         if (dev == NULL)
472                 return;
473 
474         /* shutdown transfer */
475         if (dev->interrupt_in_running) {
476                 dev->interrupt_in_running = 0;
477                 mb();
478                 if (dev->udev)
479                         usb_kill_urb (dev->interrupt_in_urb);
480         }
481         if (dev->interrupt_out_busy && dev->udev)
482                 usb_kill_urb(dev->interrupt_out_urb);
483 }
484 
485 
486 /**
487  *      tower_check_for_read_packet
488  *
489  *      To get correct semantics for signals and non-blocking I/O
490  *      with packetizing we pretend not to see any data in the read buffer
491  *      until it has been there unchanged for at least
492  *      dev->packet_timeout_jiffies, or until the buffer is full.
493  */
494 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
495 {
496         spin_lock_irq (&dev->read_buffer_lock);
497         if (!packet_timeout
498             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
499             || dev->read_buffer_length == read_buffer_size) {
500                 dev->read_packet_length = dev->read_buffer_length;
501         }
502         dev->interrupt_in_done = 0;
503         spin_unlock_irq (&dev->read_buffer_lock);
504 }
505 
506 
507 /**
508  *      tower_poll
509  */
510 static unsigned int tower_poll (struct file *file, poll_table *wait)
511 {
512         struct lego_usb_tower *dev;
513         unsigned int mask = 0;
514 
515         dev = file->private_data;
516 
517         if (!dev->udev)
518                 return POLLERR | POLLHUP;
519 
520         poll_wait(file, &dev->read_wait, wait);
521         poll_wait(file, &dev->write_wait, wait);
522 
523         tower_check_for_read_packet(dev);
524         if (dev->read_packet_length > 0) {
525                 mask |= POLLIN | POLLRDNORM;
526         }
527         if (!dev->interrupt_out_busy) {
528                 mask |= POLLOUT | POLLWRNORM;
529         }
530 
531         return mask;
532 }
533 
534 
535 /**
536  *      tower_llseek
537  */
538 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
539 {
540         return -ESPIPE;         /* unseekable */
541 }
542 
543 
544 /**
545  *      tower_read
546  */
547 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
548 {
549         struct lego_usb_tower *dev;
550         size_t bytes_to_read;
551         int i;
552         int retval = 0;
553         unsigned long timeout = 0;
554 
555         dev = file->private_data;
556 
557         /* lock this object */
558         if (mutex_lock_interruptible(&dev->lock)) {
559                 retval = -ERESTARTSYS;
560                 goto exit;
561         }
562 
563         /* verify that the device wasn't unplugged */
564         if (dev->udev == NULL) {
565                 retval = -ENODEV;
566                 pr_err("No device or device unplugged %d\n", retval);
567                 goto unlock_exit;
568         }
569 
570         /* verify that we actually have some data to read */
571         if (count == 0) {
572                 dev_dbg(&dev->udev->dev, "read request of 0 bytes\n");
573                 goto unlock_exit;
574         }
575 
576         if (read_timeout) {
577                 timeout = jiffies + read_timeout * HZ / 1000;
578         }
579 
580         /* wait for data */
581         tower_check_for_read_packet (dev);
582         while (dev->read_packet_length == 0) {
583                 if (file->f_flags & O_NONBLOCK) {
584                         retval = -EAGAIN;
585                         goto unlock_exit;
586                 }
587                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
588                 if (retval < 0) {
589                         goto unlock_exit;
590                 }
591 
592                 /* reset read timeout during read or write activity */
593                 if (read_timeout
594                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
595                         timeout = jiffies + read_timeout * HZ / 1000;
596                 }
597                 /* check for read timeout */
598                 if (read_timeout && time_after (jiffies, timeout)) {
599                         retval = -ETIMEDOUT;
600                         goto unlock_exit;
601                 }
602                 tower_check_for_read_packet (dev);
603         }
604 
605         /* copy the data from read_buffer into userspace */
606         bytes_to_read = min(count, dev->read_packet_length);
607 
608         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
609                 retval = -EFAULT;
610                 goto unlock_exit;
611         }
612 
613         spin_lock_irq (&dev->read_buffer_lock);
614         dev->read_buffer_length -= bytes_to_read;
615         dev->read_packet_length -= bytes_to_read;
616         for (i=0; i<dev->read_buffer_length; i++) {
617                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
618         }
619         spin_unlock_irq (&dev->read_buffer_lock);
620 
621         retval = bytes_to_read;
622 
623 unlock_exit:
624         /* unlock the device */
625         mutex_unlock(&dev->lock);
626 
627 exit:
628         return retval;
629 }
630 
631 
632 /**
633  *      tower_write
634  */
635 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
636 {
637         struct lego_usb_tower *dev;
638         size_t bytes_to_write;
639         int retval = 0;
640 
641         dev = file->private_data;
642 
643         /* lock this object */
644         if (mutex_lock_interruptible(&dev->lock)) {
645                 retval = -ERESTARTSYS;
646                 goto exit;
647         }
648 
649         /* verify that the device wasn't unplugged */
650         if (dev->udev == NULL) {
651                 retval = -ENODEV;
652                 pr_err("No device or device unplugged %d\n", retval);
653                 goto unlock_exit;
654         }
655 
656         /* verify that we actually have some data to write */
657         if (count == 0) {
658                 dev_dbg(&dev->udev->dev, "write request of 0 bytes\n");
659                 goto unlock_exit;
660         }
661 
662         /* wait until previous transfer is finished */
663         while (dev->interrupt_out_busy) {
664                 if (file->f_flags & O_NONBLOCK) {
665                         retval = -EAGAIN;
666                         goto unlock_exit;
667                 }
668                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
669                 if (retval) {
670                         goto unlock_exit;
671                 }
672         }
673 
674         /* write the data into interrupt_out_buffer from userspace */
675         bytes_to_write = min_t(int, count, write_buffer_size);
676         dev_dbg(&dev->udev->dev, "%s: count = %Zd, bytes_to_write = %Zd\n",
677                 __func__, count, bytes_to_write);
678 
679         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
680                 retval = -EFAULT;
681                 goto unlock_exit;
682         }
683 
684         /* send off the urb */
685         usb_fill_int_urb(dev->interrupt_out_urb,
686                          dev->udev,
687                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
688                          dev->interrupt_out_buffer,
689                          bytes_to_write,
690                          tower_interrupt_out_callback,
691                          dev,
692                          dev->interrupt_out_interval);
693 
694         dev->interrupt_out_busy = 1;
695         wmb();
696 
697         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
698         if (retval) {
699                 dev->interrupt_out_busy = 0;
700                 dev_err(&dev->udev->dev,
701                         "Couldn't submit interrupt_out_urb %d\n", retval);
702                 goto unlock_exit;
703         }
704         retval = bytes_to_write;
705 
706 unlock_exit:
707         /* unlock the device */
708         mutex_unlock(&dev->lock);
709 
710 exit:
711         return retval;
712 }
713 
714 
715 /**
716  *      tower_interrupt_in_callback
717  */
718 static void tower_interrupt_in_callback (struct urb *urb)
719 {
720         struct lego_usb_tower *dev = urb->context;
721         int status = urb->status;
722         int retval;
723 
724         lego_usb_tower_debug_data(&dev->udev->dev, __func__,
725                                   urb->actual_length, urb->transfer_buffer);
726 
727         if (status) {
728                 if (status == -ENOENT ||
729                     status == -ECONNRESET ||
730                     status == -ESHUTDOWN) {
731                         goto exit;
732                 } else {
733                         dev_dbg(&dev->udev->dev,
734                                 "%s: nonzero status received: %d\n", __func__,
735                                 status);
736                         goto resubmit; /* maybe we can recover */
737                 }
738         }
739 
740         if (urb->actual_length > 0) {
741                 spin_lock (&dev->read_buffer_lock);
742                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
743                         memcpy (dev->read_buffer + dev->read_buffer_length,
744                                 dev->interrupt_in_buffer,
745                                 urb->actual_length);
746                         dev->read_buffer_length += urb->actual_length;
747                         dev->read_last_arrival = jiffies;
748                         dev_dbg(&dev->udev->dev, "%s: received %d bytes\n",
749                                 __func__, urb->actual_length);
750                 } else {
751                         pr_warn("read_buffer overflow, %d bytes dropped\n",
752                                 urb->actual_length);
753                 }
754                 spin_unlock (&dev->read_buffer_lock);
755         }
756 
757 resubmit:
758         /* resubmit if we're still running */
759         if (dev->interrupt_in_running && dev->udev) {
760                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
761                 if (retval)
762                         dev_err(&dev->udev->dev,
763                                 "%s: usb_submit_urb failed (%d)\n",
764                                 __func__, retval);
765         }
766 
767 exit:
768         dev->interrupt_in_done = 1;
769         wake_up_interruptible (&dev->read_wait);
770 }
771 
772 
773 /**
774  *      tower_interrupt_out_callback
775  */
776 static void tower_interrupt_out_callback (struct urb *urb)
777 {
778         struct lego_usb_tower *dev = urb->context;
779         int status = urb->status;
780 
781         lego_usb_tower_debug_data(&dev->udev->dev, __func__,
782                                   urb->actual_length, urb->transfer_buffer);
783 
784         /* sync/async unlink faults aren't errors */
785         if (status && !(status == -ENOENT ||
786                         status == -ECONNRESET ||
787                         status == -ESHUTDOWN)) {
788                 dev_dbg(&dev->udev->dev,
789                         "%s: nonzero write bulk status received: %d\n", __func__,
790                         status);
791         }
792 
793         dev->interrupt_out_busy = 0;
794         wake_up_interruptible(&dev->write_wait);
795 }
796 
797 
798 /**
799  *      tower_probe
800  *
801  *      Called by the usb core when a new device is connected that it thinks
802  *      this driver might be interested in.
803  */
804 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
805 {
806         struct device *idev = &interface->dev;
807         struct usb_device *udev = interface_to_usbdev(interface);
808         struct lego_usb_tower *dev = NULL;
809         struct usb_host_interface *iface_desc;
810         struct usb_endpoint_descriptor* endpoint;
811         struct tower_get_version_reply get_version_reply;
812         int i;
813         int retval = -ENOMEM;
814         int result;
815 
816         /* allocate memory for our device state and initialize it */
817 
818         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
819 
820         if (dev == NULL) {
821                 dev_err(idev, "Out of memory\n");
822                 goto exit;
823         }
824 
825         mutex_init(&dev->lock);
826 
827         dev->udev = udev;
828         dev->open_count = 0;
829 
830         dev->read_buffer = NULL;
831         dev->read_buffer_length = 0;
832         dev->read_packet_length = 0;
833         spin_lock_init (&dev->read_buffer_lock);
834         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
835         dev->read_last_arrival = jiffies;
836 
837         init_waitqueue_head (&dev->read_wait);
838         init_waitqueue_head (&dev->write_wait);
839 
840         dev->interrupt_in_buffer = NULL;
841         dev->interrupt_in_endpoint = NULL;
842         dev->interrupt_in_urb = NULL;
843         dev->interrupt_in_running = 0;
844         dev->interrupt_in_done = 0;
845 
846         dev->interrupt_out_buffer = NULL;
847         dev->interrupt_out_endpoint = NULL;
848         dev->interrupt_out_urb = NULL;
849         dev->interrupt_out_busy = 0;
850 
851         iface_desc = interface->cur_altsetting;
852 
853         /* set up the endpoint information */
854         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
855                 endpoint = &iface_desc->endpoint[i].desc;
856 
857                 if (usb_endpoint_xfer_int(endpoint)) {
858                         if (usb_endpoint_dir_in(endpoint))
859                                 dev->interrupt_in_endpoint = endpoint;
860                         else
861                                 dev->interrupt_out_endpoint = endpoint;
862                 }
863         }
864         if(dev->interrupt_in_endpoint == NULL) {
865                 dev_err(idev, "interrupt in endpoint not found\n");
866                 goto error;
867         }
868         if (dev->interrupt_out_endpoint == NULL) {
869                 dev_err(idev, "interrupt out endpoint not found\n");
870                 goto error;
871         }
872 
873         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
874         if (!dev->read_buffer) {
875                 dev_err(idev, "Couldn't allocate read_buffer\n");
876                 goto error;
877         }
878         dev->interrupt_in_buffer = kmalloc (usb_endpoint_maxp(dev->interrupt_in_endpoint), GFP_KERNEL);
879         if (!dev->interrupt_in_buffer) {
880                 dev_err(idev, "Couldn't allocate interrupt_in_buffer\n");
881                 goto error;
882         }
883         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
884         if (!dev->interrupt_in_urb) {
885                 dev_err(idev, "Couldn't allocate interrupt_in_urb\n");
886                 goto error;
887         }
888         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
889         if (!dev->interrupt_out_buffer) {
890                 dev_err(idev, "Couldn't allocate interrupt_out_buffer\n");
891                 goto error;
892         }
893         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
894         if (!dev->interrupt_out_urb) {
895                 dev_err(idev, "Couldn't allocate interrupt_out_urb\n");
896                 goto error;
897         }
898         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
899         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
900 
901         /* we can register the device now, as it is ready */
902         usb_set_intfdata (interface, dev);
903 
904         retval = usb_register_dev (interface, &tower_class);
905 
906         if (retval) {
907                 /* something prevented us from registering this driver */
908                 dev_err(idev, "Not able to get a minor for this device.\n");
909                 usb_set_intfdata (interface, NULL);
910                 goto error;
911         }
912         dev->minor = interface->minor;
913 
914         /* let the user know what node this device is now attached to */
915         dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
916                  "%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
917                  USB_MAJOR, dev->minor);
918 
919         /* get the firmware version and log it */
920         result = usb_control_msg (udev,
921                                   usb_rcvctrlpipe(udev, 0),
922                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
923                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
924                                   0,
925                                   0,
926                                   &get_version_reply,
927                                   sizeof(get_version_reply),
928                                   1000);
929         if (result < 0) {
930                 dev_err(idev, "LEGO USB Tower get version control request failed\n");
931                 retval = result;
932                 goto error;
933         }
934         dev_info(&interface->dev, "LEGO USB Tower firmware version is %d.%d "
935                  "build %d\n", get_version_reply.major,
936                  get_version_reply.minor,
937                  le16_to_cpu(get_version_reply.build_no));
938 
939 
940 exit:
941         return retval;
942 
943 error:
944         tower_delete(dev);
945         return retval;
946 }
947 
948 
949 /**
950  *      tower_disconnect
951  *
952  *      Called by the usb core when the device is removed from the system.
953  */
954 static void tower_disconnect (struct usb_interface *interface)
955 {
956         struct lego_usb_tower *dev;
957         int minor;
958 
959         dev = usb_get_intfdata (interface);
960         mutex_lock(&open_disc_mutex);
961         usb_set_intfdata (interface, NULL);
962 
963         minor = dev->minor;
964 
965         /* give back our minor */
966         usb_deregister_dev (interface, &tower_class);
967 
968         mutex_lock(&dev->lock);
969         mutex_unlock(&open_disc_mutex);
970 
971         /* if the device is not opened, then we clean up right now */
972         if (!dev->open_count) {
973                 mutex_unlock(&dev->lock);
974                 tower_delete (dev);
975         } else {
976                 dev->udev = NULL;
977                 /* wake up pollers */
978                 wake_up_interruptible_all(&dev->read_wait);
979                 wake_up_interruptible_all(&dev->write_wait);
980                 mutex_unlock(&dev->lock);
981         }
982 
983         dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
984                  (minor - LEGO_USB_TOWER_MINOR_BASE));
985 }
986 
987 module_usb_driver(tower_driver);
988 
989 MODULE_AUTHOR(DRIVER_AUTHOR);
990 MODULE_DESCRIPTION(DRIVER_DESC);
991 #ifdef MODULE_LICENSE
992 MODULE_LICENSE("GPL");
993 #endif
994 

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