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  */
  75
  76 #include <linux/config.h>
  77 #include <linux/kernel.h>
  78 #include <linux/errno.h>
  79 #include <linux/init.h>
  80 #include <linux/slab.h>
  81 #include <linux/module.h>
  82 #include <linux/smp_lock.h>
  83 #include <linux/completion.h>
  84 #include <asm/uaccess.h>
  85 #include <linux/usb.h>
  86 #include <linux/poll.h>
  87
  88
  89 #ifdef CONFIG_USB_DEBUG
  90         static int debug = 4;
  91 #else
  92         static int debug = 0;
  93 #endif
  94
  95 /* Use our own dbg macro */
  96 #undef dbg
  97 #define dbg(lvl, format, arg...) do { if (debug >= lvl) printk(KERN_DEBUG  __FILE__ ": " format "\n", ## arg); } while (0)
  98
  99
 100 /* Version Information */
 101 #define DRIVER_VERSION "v0.95"
 102 #define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
 103 #define DRIVER_DESC "LEGO USB Tower Driver"
 104
 105 /* Module parameters */
 106 MODULE_PARM(debug, "i");
 107 MODULE_PARM_DESC(debug, "Debug enabled or not");
 108
 109 /* The defaults are chosen to work with the latest versions of leJOS and NQC.
 110  */
 111
 112 /* Some legacy software likes to receive packets in one piece.
 113  * In this case read_buffer_size should exceed the maximal packet length
 114  * (417 for datalog uploads), and packet_timeout should be set.
 115  */
 116 static size_t read_buffer_size = 480;
 117 MODULE_PARM(read_buffer_size, "i");
 118 MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
 119
 120 /* Some legacy software likes to send packets in one piece.
 121  * In this case write_buffer_size should exceed the maximal packet length
 122  * (417 for firmware and program downloads).
 123  * A problem with long writes is that the following read may time out
 124  * if the software is not prepared to wait long enough.
 125  */
 126 static size_t write_buffer_size = 480;
 127 MODULE_PARM(write_buffer_size, "i");
 128 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 129
 130 /* Some legacy software expects reads to contain whole LASM packets.
 131  * To achieve this, characters which arrive before a packet timeout
 132  * occurs will be returned in a single read operation.
 133  * A problem with long reads is that the software may time out
 134  * if it is not prepared to wait long enough.
 135  * The packet timeout should be greater than the time between the
 136  * reception of subsequent characters, which should arrive about
 137  * every 5ms for the standard 2400 baud.
 138  * Set it to 0 to disable.
 139  */
 140 static int packet_timeout = 50;
 141 MODULE_PARM(packet_timeout, "i");
 142 MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
 143
 144 /* Some legacy software expects blocking reads to time out.
 145  * Timeout occurs after the specified time of read and write inactivity.
 146  * Set it to 0 to disable.
 147  */
 148 static int read_timeout = 200;
 149 MODULE_PARM(read_timeout, "i");
 150 MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
 151
 152 /* As of kernel version 2.6.4 ehci-hcd uses an
 153  * "only one interrupt transfer per frame" shortcut
 154  * to simplify the scheduling of periodic transfers.
 155  * This conflicts with our standard 1ms intervals for in and out URBs.
 156  * We use default intervals of 2ms for in and 8ms for out transfers,
 157  * which is fast enough for 2400 baud and allows a small additional load.
 158  * Increase the interval to allow more devices that do interrupt transfers,
 159  * or set to 0 to use the standard interval from the endpoint descriptors.
 160  */
 161 static int interrupt_in_interval = 2;
 162 MODULE_PARM(interrupt_in_interval, "i");
 163 MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
 164
 165 static int interrupt_out_interval = 8;
 166 MODULE_PARM(interrupt_out_interval, "i");
 167 MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
 168
 169 /* Define these values to match your device */
 170 #define LEGO_USB_TOWER_VENDOR_ID        0x0694
 171 #define LEGO_USB_TOWER_PRODUCT_ID       0x0001
 172
 173 /* Vendor requests */
 174 #define LEGO_USB_TOWER_REQUEST_RESET            0x04
 175 #define LEGO_USB_TOWER_REQUEST_GET_VERSION      0xFD
 176
 177 struct tower_reset_reply {
 178         __u16 size;             /* little-endian */
 179         __u8 err_code;
 180         __u8 spare;
 181 } __attribute__ ((packed));
 182
 183 struct tower_get_version_reply {
 184         __u16 size;             /* little-endian */
 185         __u8 err_code;
 186         __u8 spare;
 187         __u8 major;
 188         __u8 minor;
 189         __u16 build_no;         /* little-endian */
 190 } __attribute__ ((packed));
 191
 192
 193 /* table of devices that work with this driver */
 194 static struct usb_device_id tower_table [] = {
 195         { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
 196         { }                                     /* Terminating entry */
 197 };
 198
 199 MODULE_DEVICE_TABLE (usb, tower_table);
 200
 201 #define LEGO_USB_TOWER_MINOR_BASE       160
 202
 203
 204 /* Structure to hold all of our device specific stuff */
 205 struct lego_usb_tower {
 206         struct semaphore        sem;            /* locks this structure */
 207         struct usb_device*      udev;           /* save off the usb device pointer */
 208         unsigned char           minor;          /* the starting minor number for this device */
 209
 210         int                     open_count;     /* number of times this port has been opened */
 211
 212         char*                   read_buffer;
 213         size_t                  read_buffer_length; /* this much came in */
 214         size_t                  read_packet_length; /* this much will be returned on read */
 215         spinlock_t              read_buffer_lock;
 216         int                     packet_timeout_jiffies;
 217         unsigned long           read_last_arrival;
 218
 219         wait_queue_head_t       read_wait;
 220         wait_queue_head_t       write_wait;
 221
 222         char*                   interrupt_in_buffer;
 223         struct usb_endpoint_descriptor* interrupt_in_endpoint;
 224         struct urb*             interrupt_in_urb;
 225         int                     interrupt_in_interval;
 226         int                     interrupt_in_running;
 227         int                     interrupt_in_done;
 228
 229         char*                   interrupt_out_buffer;
 230         struct usb_endpoint_descriptor* interrupt_out_endpoint;
 231         struct urb*             interrupt_out_urb;
 232         int                     interrupt_out_interval;
 233         int                     interrupt_out_busy;
 234
 235 };
 236
 237
 238 /* local function prototypes */
 239 static ssize_t tower_read       (struct file *file, char *buffer, size_t count, loff_t *ppos);
 240 static ssize_t tower_write      (struct file *file, const char *buffer, size_t count, loff_t *ppos);
 241 static inline void tower_delete (struct lego_usb_tower *dev);
 242 static int tower_open           (struct inode *inode, struct file *file);
 243 static int tower_release        (struct inode *inode, struct file *file);
 244 static unsigned int tower_poll  (struct file *file, poll_table *wait);
 245 static loff_t tower_llseek      (struct file *file, loff_t off, int whence);
 246
 247 static void tower_abort_transfers (struct lego_usb_tower *dev);
 248 static void tower_check_for_read_packet (struct lego_usb_tower *dev);
 249 static void tower_interrupt_in_callback (struct urb *urb, struct pt_regs *regs);
 250 static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs);
 251
 252 static int  tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
 253 static void tower_disconnect    (struct usb_interface *interface);
 254
 255
 256 /* prevent races between open() and disconnect */
 257 static DECLARE_MUTEX (disconnect_sem);
 258
 259 /* file operations needed when we register this driver */
 260 static struct file_operations tower_fops = {
 261         .owner =        THIS_MODULE,
 262         .read  =        tower_read,
 263         .write =        tower_write,
 264         .open =         tower_open,
 265         .release =      tower_release,
 266         .poll =         tower_poll,
 267         .llseek =       tower_llseek,
 268 };
 269
 270 /*
 271  * usb class driver info in order to get a minor number from the usb core,
 272  * and to have the device registered with devfs and the driver core
 273  */
 274 static struct usb_class_driver tower_class = {
 275         .name =         "usb/legousbtower%d",
 276         .fops =         &tower_fops,
 277         .mode =         S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH,
 278         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
 279 };
 280
 281
 282 /* usb specific object needed to register this driver with the usb subsystem */
 283 static struct usb_driver tower_driver = {
 284         .owner =        THIS_MODULE,
 285         .name =         "legousbtower",
 286         .probe =        tower_probe,
 287         .disconnect =   tower_disconnect,
 288         .id_table =     tower_table,
 289 };
 290
 291
 292 /**
 293  *      lego_usb_tower_debug_data
 294  */
 295 static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
 296 {
 297         int i;
 298
 299         if (debug < level)
 300                 return;
 301
 302         printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
 303         for (i = 0; i < size; ++i) {
 304                 printk ("%.2x ", data[i]);
 305         }
 306         printk ("\n");
 307 }
 308
 309
 310 /**
 311  *      tower_delete
 312  */
 313 static inline void tower_delete (struct lego_usb_tower *dev)
 314 {
 315         dbg(2, "%s: enter", __FUNCTION__);
 316
 317         tower_abort_transfers (dev);
 318
 319         /* free data structures */
 320         if (dev->interrupt_in_urb != NULL) {
 321                 usb_free_urb (dev->interrupt_in_urb);
 322         }
 323         if (dev->interrupt_out_urb != NULL) {
 324                 usb_free_urb (dev->interrupt_out_urb);
 325         }
 326         kfree (dev->read_buffer);
 327         kfree (dev->interrupt_in_buffer);
 328         kfree (dev->interrupt_out_buffer);
 329         kfree (dev);
 330
 331         dbg(2, "%s: leave", __FUNCTION__);
 332 }
 333
 334
 335 /**
 336  *      tower_open
 337  */
 338 static int tower_open (struct inode *inode, struct file *file)
 339 {
 340         struct lego_usb_tower *dev = NULL;
 341         int subminor;
 342         int retval = 0;
 343         struct usb_interface *interface;
 344
 345         dbg(2, "%s: enter", __FUNCTION__);
 346
 347         subminor = iminor(inode);
 348
 349         down (&disconnect_sem);
 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                      __FUNCTION__, subminor);
 356                 retval = -ENODEV;
 357                 goto unlock_disconnect_exit;
 358         }
 359
 360         dev = usb_get_intfdata(interface);
 361
 362         if (!dev) {
 363                 retval = -ENODEV;
 364                 goto unlock_disconnect_exit;
 365         }
 366
 367         /* lock this device */
 368         if (down_interruptible (&dev->sem)) {
 369                 retval = -ERESTARTSYS;
 370                 goto unlock_disconnect_exit;
 371         }
 372
 373         /* allow opening only once */
 374         if (dev->open_count) {
 375                 retval = -EBUSY;
 376                 goto unlock_exit;
 377         }
 378         dev->open_count = 1;
 379
 380         /* initialize in direction */
 381         dev->read_buffer_length = 0;
 382         dev->read_packet_length = 0;
 383         usb_fill_int_urb (dev->interrupt_in_urb,
 384                           dev->udev,
 385                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
 386                           dev->interrupt_in_buffer,
 387                           dev->interrupt_in_endpoint->wMaxPacketSize,
 388                           tower_interrupt_in_callback,
 389                           dev,
 390                           dev->interrupt_in_interval);
 391
 392         dev->interrupt_in_running = 1;
 393         dev->interrupt_in_done = 0;
 394         mb();
 395
 396         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
 397         if (retval) {
 398                 err("Couldn't submit interrupt_in_urb %d", retval);
 399                 dev->interrupt_in_running = 0;
 400                 dev->open_count = 0;
 401                 goto unlock_exit;
 402         }
 403
 404         /* save device in the file's private structure */
 405         file->private_data = dev;
 406
 407 unlock_exit:
 408         up (&dev->sem);
 409
 410 unlock_disconnect_exit:
 411         up (&disconnect_sem);
 412
 413         dbg(2, "%s: leave, return value %d ", __FUNCTION__, retval);
 414
 415         return retval;
 416 }
 417
 418 /**
 419  *      tower_release
 420  */
 421 static int tower_release (struct inode *inode, struct file *file)
 422 {
 423         struct lego_usb_tower *dev;
 424         int retval = 0;
 425
 426         dbg(2, "%s: enter", __FUNCTION__);
 427
 428         dev = (struct lego_usb_tower *)file->private_data;
 429
 430         if (dev == NULL) {
 431                 dbg(1, "%s: object is NULL", __FUNCTION__);
 432                 retval = -ENODEV;
 433                 goto exit;
 434         }
 435
 436         if (down_interruptible (&dev->sem)) {
 437                 retval = -ERESTARTSYS;
 438                 goto exit;
 439         }
 440
 441         if (dev->open_count != 1) {
 442                 dbg(1, "%s: device not opened exactly once", __FUNCTION__);
 443                 retval = -ENODEV;
 444                 goto unlock_exit;
 445         }
 446         if (dev->udev == NULL) {
 447                 /* the device was unplugged before the file was released */
 448                 up (&dev->sem); /* unlock here as tower_delete frees dev */
 449                 tower_delete (dev);
 450                 goto exit;
 451         }
 452
 453         /* wait until write transfer is finished */
 454         if (dev->interrupt_out_busy) {
 455                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 456         }
 457         tower_abort_transfers (dev);
 458         dev->open_count = 0;
 459
 460 unlock_exit:
 461         up (&dev->sem);
 462
 463 exit:
 464         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 465         return retval;
 466 }
 467
 468
 469 /**
 470  *      tower_abort_transfers
 471  *      aborts transfers and frees associated data structures
 472  */
 473 static void tower_abort_transfers (struct lego_usb_tower *dev)
 474 {
 475         dbg(2, "%s: enter", __FUNCTION__);
 476
 477         if (dev == NULL) {
 478                 dbg(1, "%s: dev is null", __FUNCTION__);
 479                 goto exit;
 480         }
 481
 482         /* shutdown transfer */
 483         if (dev->interrupt_in_running) {
 484                 dev->interrupt_in_running = 0;
 485                 mb();
 486                 if (dev->interrupt_in_urb != NULL && dev->udev) {
 487                         usb_unlink_urb (dev->interrupt_in_urb);
 488                 }
 489         }
 490         if (dev->interrupt_out_busy) {
 491                 if (dev->interrupt_out_urb != NULL && dev->udev) {
 492                         usb_unlink_urb (dev->interrupt_out_urb);
 493                 }
 494         }
 495
 496 exit:
 497         dbg(2, "%s: leave", __FUNCTION__);
 498 }
 499
 500
 501 /**
 502  *      tower_check_for_read_packet
 503  *
 504  *      To get correct semantics for signals and non-blocking I/O
 505  *      with packetizing we pretend not to see any data in the read buffer
 506  *      until it has been there unchanged for at least
 507  *      dev->packet_timeout_jiffies, or until the buffer is full.
 508  */
 509 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
 510 {
 511         spin_lock_irq (&dev->read_buffer_lock);
 512         if (!packet_timeout
 513             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
 514             || dev->read_buffer_length == read_buffer_size) {
 515                 dev->read_packet_length = dev->read_buffer_length;
 516         }
 517         dev->interrupt_in_done = 0;
 518         spin_unlock_irq (&dev->read_buffer_lock);
 519 }
 520
 521
 522 /**
 523  *      tower_poll
 524  */
 525 static unsigned int tower_poll (struct file *file, poll_table *wait)
 526 {
 527         struct lego_usb_tower *dev;
 528         unsigned int mask = 0;
 529
 530         dbg(2, "%s: enter", __FUNCTION__);
 531
 532         dev = file->private_data;
 533
 534         poll_wait(file, &dev->read_wait, wait);
 535         poll_wait(file, &dev->write_wait, wait);
 536
 537         tower_check_for_read_packet(dev);
 538         if (dev->read_packet_length > 0) {
 539                 mask |= POLLIN | POLLRDNORM;
 540         }
 541         if (!dev->interrupt_out_busy) {
 542                 mask |= POLLOUT | POLLWRNORM;
 543         }
 544
 545         dbg(2, "%s: leave, mask = %d", __FUNCTION__, mask);
 546
 547         return mask;
 548 }
 549
 550
 551 /**
 552  *      tower_llseek
 553  */
 554 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
 555 {
 556         return -ESPIPE;         /* unseekable */
 557 }
 558
 559
 560 /**
 561  *      tower_read
 562  */
 563 static ssize_t tower_read (struct file *file, char *buffer, size_t count, loff_t *ppos)
 564 {
 565         struct lego_usb_tower *dev;
 566         size_t bytes_to_read;
 567         int i;
 568         int retval = 0;
 569         unsigned long timeout = 0;
 570
 571         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 572
 573         dev = (struct lego_usb_tower *)file->private_data;
 574
 575         /* lock this object */
 576         if (down_interruptible (&dev->sem)) {
 577                 retval = -ERESTARTSYS;
 578                 goto exit;
 579         }
 580
 581         /* verify that the device wasn't unplugged */
 582         if (dev->udev == NULL) {
 583                 retval = -ENODEV;
 584                 err("No device or device unplugged %d", retval);
 585                 goto unlock_exit;
 586         }
 587
 588         /* verify that we actually have some data to read */
 589         if (count == 0) {
 590                 dbg(1, "%s: read request of 0 bytes", __FUNCTION__);
 591                 goto unlock_exit;
 592         }
 593
 594         if (read_timeout) {
 595                 timeout = jiffies + read_timeout * HZ / 1000;
 596         }
 597
 598         /* wait for data */
 599         tower_check_for_read_packet (dev);
 600         while (dev->read_packet_length == 0) {
 601                 if (file->f_flags & O_NONBLOCK) {
 602                         retval = -EAGAIN;
 603                         goto unlock_exit;
 604                 }
 605                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
 606                 if (retval < 0) {
 607                         goto unlock_exit;
 608                 }
 609
 610                 /* reset read timeout during read or write activity */
 611                 if (read_timeout
 612                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
 613                         timeout = jiffies + read_timeout * HZ / 1000;
 614                 }
 615                 /* check for read timeout */
 616                 if (read_timeout && time_after (jiffies, timeout)) {
 617                         retval = -ETIMEDOUT;
 618                         goto unlock_exit;
 619                 }
 620                 tower_check_for_read_packet (dev);
 621         }
 622
 623         /* copy the data from read_buffer into userspace */
 624         bytes_to_read = min(count, dev->read_packet_length);
 625
 626         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
 627                 retval = -EFAULT;
 628                 goto unlock_exit;
 629         }
 630
 631         spin_lock_irq (&dev->read_buffer_lock);
 632         dev->read_buffer_length -= bytes_to_read;
 633         dev->read_packet_length -= bytes_to_read;
 634         for (i=0; i<dev->read_buffer_length; i++) {
 635                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
 636         }
 637         spin_unlock_irq (&dev->read_buffer_lock);
 638
 639         retval = bytes_to_read;
 640
 641 unlock_exit:
 642         /* unlock the device */
 643         up (&dev->sem);
 644
 645 exit:
 646         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 647         return retval;
 648 }
 649
 650
 651 /**
 652  *      tower_write
 653  */
 654 static ssize_t tower_write (struct file *file, const char *buffer, size_t count, loff_t *ppos)
 655 {
 656         struct lego_usb_tower *dev;
 657         size_t bytes_to_write;
 658         int retval = 0;
 659
 660         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 661
 662         dev = (struct lego_usb_tower *)file->private_data;
 663
 664         /* lock this object */
 665         if (down_interruptible (&dev->sem)) {
 666                 retval = -ERESTARTSYS;
 667                 goto exit;
 668         }
 669
 670         /* verify that the device wasn't unplugged */
 671         if (dev->udev == NULL) {
 672                 retval = -ENODEV;
 673                 err("No device or device unplugged %d", retval);
 674                 goto unlock_exit;
 675         }
 676
 677         /* verify that we actually have some data to write */
 678         if (count == 0) {
 679                 dbg(1, "%s: write request of 0 bytes", __FUNCTION__);
 680                 goto unlock_exit;
 681         }
 682
 683         /* wait until previous transfer is finished */
 684         while (dev->interrupt_out_busy) {
 685                 if (file->f_flags & O_NONBLOCK) {
 686                         retval = -EAGAIN;
 687                         goto unlock_exit;
 688                 }
 689                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
 690                 if (retval) {
 691                         goto unlock_exit;
 692                 }
 693         }
 694
 695         /* write the data into interrupt_out_buffer from userspace */
 696         bytes_to_write = min(count, write_buffer_size);
 697         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __FUNCTION__, count, bytes_to_write);
 698
 699         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 700                 retval = -EFAULT;
 701                 goto unlock_exit;
 702         }
 703
 704         /* send off the urb */
 705         usb_fill_int_urb(dev->interrupt_out_urb,
 706                          dev->udev,
 707                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 708                          dev->interrupt_out_buffer,
 709                          bytes_to_write,
 710                          tower_interrupt_out_callback,
 711                          dev,
 712                          dev->interrupt_out_interval);
 713
 714         dev->interrupt_out_busy = 1;
 715         wmb();
 716
 717         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
 718         if (retval) {
 719                 dev->interrupt_out_busy = 0;
 720                 err("Couldn't submit interrupt_out_urb %d", retval);
 721                 goto unlock_exit;
 722         }
 723         retval = bytes_to_write;
 724
 725 unlock_exit:
 726         /* unlock the device */
 727         up (&dev->sem);
 728
 729 exit:
 730         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 731
 732         return retval;
 733 }
 734
 735
 736 /**
 737  *      tower_interrupt_in_callback
 738  */
 739 static void tower_interrupt_in_callback (struct urb *urb, struct pt_regs *regs)
 740 {
 741         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 742         int retval;
 743
 744         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
 745
 746         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 747
 748         if (urb->status) {
 749                 if (urb->status == -ENOENT ||
 750                     urb->status == -ECONNRESET ||
 751                     urb->status == -ESHUTDOWN) {
 752                         goto exit;
 753                 } else {
 754                         dbg(1, "%s: nonzero status received: %d", __FUNCTION__, urb->status);
 755                         goto resubmit; /* maybe we can recover */
 756                 }
 757         }
 758
 759         if (urb->actual_length > 0) {
 760                 spin_lock (&dev->read_buffer_lock);
 761                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
 762                         memcpy (dev->read_buffer + dev->read_buffer_length,
 763                                 dev->interrupt_in_buffer,
 764                                 urb->actual_length);
 765                         dev->read_buffer_length += urb->actual_length;
 766                         dev->read_last_arrival = jiffies;
 767                         dbg(3, "%s: received %d bytes", __FUNCTION__, urb->actual_length);
 768                 } else {
 769                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __FUNCTION__, urb->actual_length);
 770                 }
 771                 spin_unlock (&dev->read_buffer_lock);
 772         }
 773
 774 resubmit:
 775         /* resubmit if we're still running */
 776         if (dev->interrupt_in_running && dev->udev) {
 777                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
 778                 if (retval) {
 779                         err("%s: usb_submit_urb failed (%d)", __FUNCTION__, retval);
 780                 }
 781         }
 782
 783 exit:
 784         dev->interrupt_in_done = 1;
 785         wake_up_interruptible (&dev->read_wait);
 786
 787         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 788         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
 789 }
 790
 791
 792 /**
 793  *      tower_interrupt_out_callback
 794  */
 795 static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs)
 796 {
 797         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 798
 799         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
 800         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 801
 802         /* sync/async unlink faults aren't errors */
 803         if (urb->status && !(urb->status == -ENOENT ||
 804                              urb->status == -ECONNRESET ||
 805                              urb->status == -ESHUTDOWN)) {
 806                 dbg(1, "%s - nonzero write bulk status received: %d",
 807                     __FUNCTION__, urb->status);
 808         }
 809
 810         dev->interrupt_out_busy = 0;
 811         wake_up_interruptible(&dev->write_wait);
 812
 813         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 814         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
 815 }
 816
 817
 818 /**
 819  *      tower_probe
 820  *
 821  *      Called by the usb core when a new device is connected that it thinks
 822  *      this driver might be interested in.
 823  */
 824 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
 825 {
 826         struct usb_device *udev = interface_to_usbdev(interface);
 827         struct lego_usb_tower *dev = NULL;
 828         struct usb_host_interface *iface_desc;
 829         struct usb_endpoint_descriptor* endpoint;
 830         struct tower_reset_reply reset_reply;
 831         struct tower_get_version_reply get_version_reply;
 832         int i;
 833         int retval = -ENOMEM;
 834         int result;
 835
 836         dbg(2, "%s: enter", __FUNCTION__);
 837
 838         if (udev == NULL) {
 839                 info ("udev is NULL.");
 840         }
 841
 842         /* See if the device offered us matches what we can accept */
 843         if ((udev->descriptor.idVendor != LEGO_USB_TOWER_VENDOR_ID) ||
 844             (udev->descriptor.idProduct != LEGO_USB_TOWER_PRODUCT_ID)) {
 845                 return -ENODEV;
 846         }
 847
 848
 849         /* allocate memory for our device state and intialize it */
 850
 851         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
 852
 853         if (dev == NULL) {
 854                 err ("Out of memory");
 855                 goto exit;
 856         }
 857
 858         init_MUTEX (&dev->sem);
 859
 860         dev->udev = udev;
 861         dev->open_count = 0;
 862
 863         dev->read_buffer = NULL;
 864         dev->read_buffer_length = 0;
 865         dev->read_packet_length = 0;
 866         spin_lock_init (&dev->read_buffer_lock);
 867         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
 868         dev->read_last_arrival = jiffies;
 869
 870         init_waitqueue_head (&dev->read_wait);
 871         init_waitqueue_head (&dev->write_wait);
 872
 873         dev->interrupt_in_buffer = NULL;
 874         dev->interrupt_in_endpoint = NULL;
 875         dev->interrupt_in_urb = NULL;
 876         dev->interrupt_in_running = 0;
 877         dev->interrupt_in_done = 0;
 878
 879         dev->interrupt_out_buffer = NULL;
 880         dev->interrupt_out_endpoint = NULL;
 881         dev->interrupt_out_urb = NULL;
 882         dev->interrupt_out_busy = 0;
 883
 884         iface_desc = interface->cur_altsetting;
 885
 886         /* set up the endpoint information */
 887         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 888                 endpoint = &iface_desc->endpoint[i].desc;
 889
 890                 if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN) &&
 891                     ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
 892                         dev->interrupt_in_endpoint = endpoint;
 893                 }
 894
 895                 if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT) &&
 896                     ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
 897                         dev->interrupt_out_endpoint = endpoint;
 898                 }
 899         }
 900         if(dev->interrupt_in_endpoint == NULL) {
 901                 err("interrupt in endpoint not found");
 902                 goto error;
 903         }
 904         if (dev->interrupt_out_endpoint == NULL) {
 905                 err("interrupt out endpoint not found");
 906                 goto error;
 907         }
 908
 909         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
 910         if (!dev->read_buffer) {
 911                 err("Couldn't allocate read_buffer");
 912                 goto error;
 913         }
 914         dev->interrupt_in_buffer = kmalloc (dev->interrupt_in_endpoint->wMaxPacketSize, GFP_KERNEL);
 915         if (!dev->interrupt_in_buffer) {
 916                 err("Couldn't allocate interrupt_in_buffer");
 917                 goto error;
 918         }
 919         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 920         if (!dev->interrupt_in_urb) {
 921                 err("Couldn't allocate interrupt_in_urb");
 922                 goto error;
 923         }
 924         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
 925         if (!dev->interrupt_out_buffer) {
 926                 err("Couldn't allocate interrupt_out_buffer");
 927                 goto error;
 928         }
 929         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 930         if (!dev->interrupt_out_urb) {
 931                 err("Couldn't allocate interrupt_out_urb");
 932                 goto error;
 933         }
 934         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 935         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 936
 937         /* we can register the device now, as it is ready */
 938         usb_set_intfdata (interface, dev);
 939
 940         retval = usb_register_dev (interface, &tower_class);
 941
 942         if (retval) {
 943                 /* something prevented us from registering this driver */
 944                 err ("Not able to get a minor for this device.");
 945                 usb_set_intfdata (interface, NULL);
 946                 goto error;
 947         }
 948         dev->minor = interface->minor;
 949
 950         /* let the user know what node this device is now attached to */
 951         info ("LEGO USB Tower #%d now attached to major %d minor %d", (dev->minor - LEGO_USB_TOWER_MINOR_BASE), USB_MAJOR, dev->minor);
 952
 953         /* reset the tower */
 954         result = usb_control_msg (udev,
 955                                   usb_rcvctrlpipe(udev, 0),
 956                                   LEGO_USB_TOWER_REQUEST_RESET,
 957                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 958                                   0,
 959                                   0,
 960                                   &reset_reply,
 961                                   sizeof(reset_reply),
 962                                   HZ);
 963         if (result < 0) {
 964                 err("LEGO USB Tower reset control request failed");
 965                 retval = result;
 966                 goto error;
 967         }
 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                                   HZ);
 979         if (result < 0) {
 980                 err("LEGO USB Tower get version control request failed");
 981                 retval = result;
 982                 goto error;
 983         }
 984         info("LEGO USB Tower firmware version is %d.%d build %d",
 985              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)", __FUNCTION__, (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", __FUNCTION__);
1012
1013         down (&disconnect_sem);
1014
1015         dev = usb_get_intfdata (interface);
1016         usb_set_intfdata (interface, NULL);
1017
1018
1019         down (&dev->sem);
1020
1021         minor = dev->minor;
1022
1023         /* give back our minor */
1024         usb_deregister_dev (interface, &tower_class);
1025
1026         /* if the device is not opened, then we clean up right now */
1027         if (!dev->open_count) {
1028                 up (&dev->sem);
1029                 tower_delete (dev);
1030         } else {
1031                 dev->udev = NULL;
1032                 up (&dev->sem);
1033         }
1034
1035         up (&disconnect_sem);
1036
1037         info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));
1038
1039         dbg(2, "%s: leave", __FUNCTION__);
1040 }
1041
1042
1043
1044 /**
1045  *      lego_usb_tower_init
1046  */
1047 static int __init lego_usb_tower_init(void)
1048 {
1049         int result;
1050         int retval = 0;
1051
1052         dbg(2, "%s: enter", __FUNCTION__);
1053
1054         /* register this driver with the USB subsystem */
1055         result = usb_register(&tower_driver);
1056         if (result < 0) {
1057                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1058                 retval = -1;
1059                 goto exit;
1060         }
1061
1062         info(DRIVER_DESC " " DRIVER_VERSION);
1063
1064 exit:
1065         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
1066
1067         return retval;
1068 }
1069
1070
1071 /**
1072  *      lego_usb_tower_exit
1073  */
1074 static void __exit lego_usb_tower_exit(void)
1075 {
1076         dbg(2, "%s: enter", __FUNCTION__);
1077
1078         /* deregister this driver with the USB subsystem */
1079         usb_deregister (&tower_driver);
1080
1081         dbg(2, "%s: leave", __FUNCTION__);
1082 }
1083
1084 module_init (lego_usb_tower_init);
1085 module_exit (lego_usb_tower_exit);
1086
1087 MODULE_AUTHOR(DRIVER_AUTHOR);
1088 MODULE_DESCRIPTION(DRIVER_DESC);
1089 #ifdef MODULE_LICENSE
1090 MODULE_LICENSE("GPL");
1091 #endif