drivers/usb/misc/legousbtower.c

   1 /*
   2  * LEGO USB Tower driver
   3  *
   4  * Copyright (C) 2003 David Glance <davidgsf@sourceforge.net>
   5  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License as
   9  *      published by the Free Software Foundation; either version 2 of
  10  *      the License, or (at your option) any later version.
  11  *
  12  * derived from USB Skeleton driver - 0.5
  13  * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
  14  *
  15  * History:
  16  *
  17  * 2001-10-13 - 0.1 js
  18  *   - first version
  19  * 2001-11-03 - 0.2 js
  20  *   - simplified buffering, one-shot URBs for writing
  21  * 2001-11-10 - 0.3 js
  22  *   - removed IOCTL (setting power/mode is more complicated, postponed)
  23  * 2001-11-28 - 0.4 js
  24  *   - added vendor commands for mode of operation and power level in open
  25  * 2001-12-04 - 0.5 js
  26  *   - set IR mode by default (by oversight 0.4 set VLL mode)
  27  * 2002-01-11 - 0.5? pcchan
  28  *   - make read buffer reusable and work around bytes_to_write issue between
  29  *     uhci and legusbtower
  30  * 2002-09-23 - 0.52 david (david@csse.uwa.edu.au)
  31  *   - imported into lejos project
  32  *   - changed wake_up to wake_up_interruptible
  33  *   - changed to use lego0 rather than tower0
  34  *   - changed dbg() to use __func__ rather than deprecated __FUNCTION__
  35  * 2003-01-12 - 0.53 david (david@csse.uwa.edu.au)
  36  *   - changed read and write to write everything or
  37  *     timeout (from a patch by Chris Riesen and Brett Thaeler driver)
  38  *   - added ioctl functionality to set timeouts
  39  * 2003-07-18 - 0.54 davidgsf (david@csse.uwa.edu.au)
  40  *   - initial import into LegoUSB project
  41  *   - merge of existing LegoUSB.c driver
  42  * 2003-07-18 - 0.56 davidgsf (david@csse.uwa.edu.au)
  43  *   - port to 2.6 style driver
  44  * 2004-02-29 - 0.6 Juergen Stuber <starblue@users.sourceforge.net>
  45  *   - fix locking
  46  *   - unlink read URBs which are no longer needed
  47  *   - allow increased buffer size, eliminates need for timeout on write
  48  *   - have read URB running continuously
  49  *   - added poll
  50  *   - forbid seeking
  51  *   - added nonblocking I/O
  52  *   - changed back __func__ to __FUNCTION__
  53  *   - read and log tower firmware version
  54  *   - reset tower on probe, avoids failure of first write
  55  * 2004-03-09 - 0.7 Juergen Stuber <starblue@users.sourceforge.net>
  56  *   - timeout read now only after inactivity, shorten default accordingly
  57  * 2004-03-11 - 0.8 Juergen Stuber <starblue@users.sourceforge.net>
  58  *   - log major, minor instead of possibly confusing device filename
  59  *   - whitespace cleanup
  60  * 2004-03-12 - 0.9 Juergen Stuber <starblue@users.sourceforge.net>
  61  *   - normalize whitespace in debug messages
  62  *   - take care about endianness in control message responses
  63  * 2004-03-13 - 0.91 Juergen Stuber <starblue@users.sourceforge.net>
  64  *   - make default intervals longer to accommodate current EHCI driver
  65  * 2004-03-19 - 0.92 Juergen Stuber <starblue@users.sourceforge.net>
  66  *   - replaced atomic_t by memory barriers
  67  * 2004-04-21 - 0.93 Juergen Stuber <starblue@users.sourceforge.net>
  68  *   - wait for completion of write urb in release (needed for remotecontrol)
  69  *   - corrected poll for write direction (missing negation)
  70  * 2004-04-22 - 0.94 Juergen Stuber <starblue@users.sourceforge.net>
  71  *   - make device locking interruptible
  72  * 2004-04-30 - 0.95 Juergen Stuber <starblue@users.sourceforge.net>
  73  *   - check for valid udev on resubmitting and unlinking urbs
  74  * 2004-08-03 - 0.96 Juergen Stuber <starblue@users.sourceforge.net>
  75  *   - move reset into open to clean out spurious data
  76  */
  77
  78 #include <linux/kernel.h>
  79 #include <linux/errno.h>
  80 #include <linux/init.h>
  81 #include <linux/slab.h>
  82 #include <linux/module.h>
  83 #include <linux/completion.h>
  84 #include <linux/mutex.h>
  85 #include <asm/uaccess.h>
  86 #include <linux/usb.h>
  87 #include <linux/poll.h>
  88
  89
  90 #ifdef CONFIG_USB_DEBUG
  91         static int debug = 4;
  92 #else
  93         static int debug = 0;
  94 #endif
  95
  96 /* Use our own dbg macro */
  97 #undef dbg
  98 #define dbg(lvl, format, arg...) do { if (debug >= lvl) printk(KERN_DEBUG  __FILE__ ": " format "\n", ## arg); } while (0)
  99
 100
 101 /* Version Information */
 102 #define DRIVER_VERSION "v0.96"
 103 #define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
 104 #define DRIVER_DESC "LEGO USB Tower Driver"
 105
 106 /* Module parameters */
 107 module_param(debug, int, S_IRUGO | S_IWUSR);
 108 MODULE_PARM_DESC(debug, "Debug enabled or not");
 109
 110 /* The defaults are chosen to work with the latest versions of leJOS and NQC.
 111  */
 112
 113 /* Some legacy software likes to receive packets in one piece.
 114  * In this case read_buffer_size should exceed the maximal packet length
 115  * (417 for datalog uploads), and packet_timeout should be set.
 116  */
 117 static int read_buffer_size = 480;
 118 module_param(read_buffer_size, int, 0);
 119 MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
 120
 121 /* Some legacy software likes to send packets in one piece.
 122  * In this case write_buffer_size should exceed the maximal packet length
 123  * (417 for firmware and program downloads).
 124  * A problem with long writes is that the following read may time out
 125  * if the software is not prepared to wait long enough.
 126  */
 127 static int write_buffer_size = 480;
 128 module_param(write_buffer_size, int, 0);
 129 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 130
 131 /* Some legacy software expects reads to contain whole LASM packets.
 132  * To achieve this, characters which arrive before a packet timeout
 133  * occurs will be returned in a single read operation.
 134  * A problem with long reads is that the software may time out
 135  * if it is not prepared to wait long enough.
 136  * The packet timeout should be greater than the time between the
 137  * reception of subsequent characters, which should arrive about
 138  * every 5ms for the standard 2400 baud.
 139  * Set it to 0 to disable.
 140  */
 141 static int packet_timeout = 50;
 142 module_param(packet_timeout, int, 0);
 143 MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
 144
 145 /* Some legacy software expects blocking reads to time out.
 146  * Timeout occurs after the specified time of read and write inactivity.
 147  * Set it to 0 to disable.
 148  */
 149 static int read_timeout = 200;
 150 module_param(read_timeout, int, 0);
 151 MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
 152
 153 /* As of kernel version 2.6.4 ehci-hcd uses an
 154  * "only one interrupt transfer per frame" shortcut
 155  * to simplify the scheduling of periodic transfers.
 156  * This conflicts with our standard 1ms intervals for in and out URBs.
 157  * We use default intervals of 2ms for in and 8ms for out transfers,
 158  * which is fast enough for 2400 baud and allows a small additional load.
 159  * Increase the interval to allow more devices that do interrupt transfers,
 160  * or set to 0 to use the standard interval from the endpoint descriptors.
 161  */
 162 static int interrupt_in_interval = 2;
 163 module_param(interrupt_in_interval, int, 0);
 164 MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
 165
 166 static int interrupt_out_interval = 8;
 167 module_param(interrupt_out_interval, int, 0);
 168 MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
 169
 170 /* Define these values to match your device */
 171 #define LEGO_USB_TOWER_VENDOR_ID        0x0694
 172 #define LEGO_USB_TOWER_PRODUCT_ID       0x0001
 173
 174 /* Vendor requests */
 175 #define LEGO_USB_TOWER_REQUEST_RESET            0x04
 176 #define LEGO_USB_TOWER_REQUEST_GET_VERSION      0xFD
 177
 178 struct tower_reset_reply {
 179         __le16 size;            /* little-endian */
 180         __u8 err_code;
 181         __u8 spare;
 182 } __attribute__ ((packed));
 183
 184 struct tower_get_version_reply {
 185         __le16 size;            /* little-endian */
 186         __u8 err_code;
 187         __u8 spare;
 188         __u8 major;
 189         __u8 minor;
 190         __le16 build_no;                /* little-endian */
 191 } __attribute__ ((packed));
 192
 193
 194 /* table of devices that work with this driver */
 195 static struct usb_device_id tower_table [] = {
 196         { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
 197         { }                                     /* Terminating entry */
 198 };
 199
 200 MODULE_DEVICE_TABLE (usb, tower_table);
 201
 202 #define LEGO_USB_TOWER_MINOR_BASE       160
 203
 204
 205 /* Structure to hold all of our device specific stuff */
 206 struct lego_usb_tower {
 207         struct semaphore        sem;            /* locks this structure */
 208         struct usb_device*      udev;           /* save off the usb device pointer */
 209         unsigned char           minor;          /* the starting minor number for this device */
 210
 211         int                     open_count;     /* number of times this port has been opened */
 212
 213         char*                   read_buffer;
 214         size_t                  read_buffer_length; /* this much came in */
 215         size_t                  read_packet_length; /* this much will be returned on read */
 216         spinlock_t              read_buffer_lock;
 217         int                     packet_timeout_jiffies;
 218         unsigned long           read_last_arrival;
 219
 220         wait_queue_head_t       read_wait;
 221         wait_queue_head_t       write_wait;
 222
 223         char*                   interrupt_in_buffer;
 224         struct usb_endpoint_descriptor* interrupt_in_endpoint;
 225         struct urb*             interrupt_in_urb;
 226         int                     interrupt_in_interval;
 227         int                     interrupt_in_running;
 228         int                     interrupt_in_done;
 229
 230         char*                   interrupt_out_buffer;
 231         struct usb_endpoint_descriptor* interrupt_out_endpoint;
 232         struct urb*             interrupt_out_urb;
 233         int                     interrupt_out_interval;
 234         int                     interrupt_out_busy;
 235
 236 };
 237
 238
 239 /* local function prototypes */
 240 static ssize_t tower_read       (struct file *file, char __user *buffer, size_t count, loff_t *ppos);
 241 static ssize_t tower_write      (struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
 242 static inline void tower_delete (struct lego_usb_tower *dev);
 243 static int tower_open           (struct inode *inode, struct file *file);
 244 static int tower_release        (struct inode *inode, struct file *file);
 245 static unsigned int tower_poll  (struct file *file, poll_table *wait);
 246 static loff_t tower_llseek      (struct file *file, loff_t off, int whence);
 247
 248 static void tower_abort_transfers (struct lego_usb_tower *dev);
 249 static void tower_check_for_read_packet (struct lego_usb_tower *dev);
 250 static void tower_interrupt_in_callback (struct urb *urb);
 251 static void tower_interrupt_out_callback (struct urb *urb);
 252
 253 static int  tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
 254 static void tower_disconnect    (struct usb_interface *interface);
 255
 256
 257 /* file operations needed when we register this driver */
 258 static const struct file_operations tower_fops = {
 259         .owner =        THIS_MODULE,
 260         .read  =        tower_read,
 261         .write =        tower_write,
 262         .open =         tower_open,
 263         .release =      tower_release,
 264         .poll =         tower_poll,
 265         .llseek =       tower_llseek,
 266 };
 267
 268 /*
 269  * usb class driver info in order to get a minor number from the usb core,
 270  * and to have the device registered with the driver core
 271  */
 272 static struct usb_class_driver tower_class = {
 273         .name =         "legousbtower%d",
 274         .fops =         &tower_fops,
 275         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
 276 };
 277
 278
 279 /* usb specific object needed to register this driver with the usb subsystem */
 280 static struct usb_driver tower_driver = {
 281         .name =         "legousbtower",
 282         .probe =        tower_probe,
 283         .disconnect =   tower_disconnect,
 284         .id_table =     tower_table,
 285 };
 286
 287
 288 /**
 289  *      lego_usb_tower_debug_data
 290  */
 291 static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
 292 {
 293         int i;
 294
 295         if (debug < level)
 296                 return;
 297
 298         printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
 299         for (i = 0; i < size; ++i) {
 300                 printk ("%.2x ", data[i]);
 301         }
 302         printk ("\n");
 303 }
 304
 305
 306 /**
 307  *      tower_delete
 308  */
 309 static inline void tower_delete (struct lego_usb_tower *dev)
 310 {
 311         dbg(2, "%s: enter", __FUNCTION__);
 312
 313         tower_abort_transfers (dev);
 314
 315         /* free data structures */
 316         usb_free_urb(dev->interrupt_in_urb);
 317         usb_free_urb(dev->interrupt_out_urb);
 318         kfree (dev->read_buffer);
 319         kfree (dev->interrupt_in_buffer);
 320         kfree (dev->interrupt_out_buffer);
 321         kfree (dev);
 322
 323         dbg(2, "%s: leave", __FUNCTION__);
 324 }
 325
 326
 327 /**
 328  *      tower_open
 329  */
 330 static int tower_open (struct inode *inode, struct file *file)
 331 {
 332         struct lego_usb_tower *dev = NULL;
 333         int subminor;
 334         int retval = 0;
 335         struct usb_interface *interface;
 336         struct tower_reset_reply reset_reply;
 337         int result;
 338
 339         dbg(2, "%s: enter", __FUNCTION__);
 340
 341         nonseekable_open(inode, file);
 342         subminor = iminor(inode);
 343
 344         interface = usb_find_interface (&tower_driver, subminor);
 345
 346         if (!interface) {
 347                 err ("%s - error, can't find device for minor %d",
 348                      __FUNCTION__, subminor);
 349                 retval = -ENODEV;
 350                 goto exit;
 351         }
 352
 353         dev = usb_get_intfdata(interface);
 354
 355         if (!dev) {
 356                 retval = -ENODEV;
 357                 goto exit;
 358         }
 359
 360         /* lock this device */
 361         if (down_interruptible (&dev->sem)) {
 362                 retval = -ERESTARTSYS;
 363                 goto exit;
 364         }
 365
 366         /* allow opening only once */
 367         if (dev->open_count) {
 368                 retval = -EBUSY;
 369                 goto unlock_exit;
 370         }
 371         dev->open_count = 1;
 372
 373         /* reset the tower */
 374         result = usb_control_msg (dev->udev,
 375                                   usb_rcvctrlpipe(dev->udev, 0),
 376                                   LEGO_USB_TOWER_REQUEST_RESET,
 377                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 378                                   0,
 379                                   0,
 380                                   &reset_reply,
 381                                   sizeof(reset_reply),
 382                                   1000);
 383         if (result < 0) {
 384                 err("LEGO USB Tower reset control request failed");
 385                 retval = result;
 386                 goto unlock_exit;
 387         }
 388
 389         /* initialize in direction */
 390         dev->read_buffer_length = 0;
 391         dev->read_packet_length = 0;
 392         usb_fill_int_urb (dev->interrupt_in_urb,
 393                           dev->udev,
 394                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
 395                           dev->interrupt_in_buffer,
 396                           le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
 397                           tower_interrupt_in_callback,
 398                           dev,
 399                           dev->interrupt_in_interval);
 400
 401         dev->interrupt_in_running = 1;
 402         dev->interrupt_in_done = 0;
 403         mb();
 404
 405         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
 406         if (retval) {
 407                 err("Couldn't submit interrupt_in_urb %d", retval);
 408                 dev->interrupt_in_running = 0;
 409                 dev->open_count = 0;
 410                 goto unlock_exit;
 411         }
 412
 413         /* save device in the file's private structure */
 414         file->private_data = dev;
 415
 416 unlock_exit:
 417         up (&dev->sem);
 418
 419 exit:
 420         dbg(2, "%s: leave, return value %d ", __FUNCTION__, retval);
 421
 422         return retval;
 423 }
 424
 425 /**
 426  *      tower_release
 427  */
 428 static int tower_release (struct inode *inode, struct file *file)
 429 {
 430         struct lego_usb_tower *dev;
 431         int retval = 0;
 432
 433         dbg(2, "%s: enter", __FUNCTION__);
 434
 435         dev = (struct lego_usb_tower *)file->private_data;
 436
 437         if (dev == NULL) {
 438                 dbg(1, "%s: object is NULL", __FUNCTION__);
 439                 retval = -ENODEV;
 440                 goto exit;
 441         }
 442
 443         if (down_interruptible (&dev->sem)) {
 444                 retval = -ERESTARTSYS;
 445                 goto exit;
 446         }
 447
 448         if (dev->open_count != 1) {
 449                 dbg(1, "%s: device not opened exactly once", __FUNCTION__);
 450                 retval = -ENODEV;
 451                 goto unlock_exit;
 452         }
 453         if (dev->udev == NULL) {
 454                 /* the device was unplugged before the file was released */
 455                 up (&dev->sem); /* unlock here as tower_delete frees dev */
 456                 tower_delete (dev);
 457                 goto exit;
 458         }
 459
 460         /* wait until write transfer is finished */
 461         if (dev->interrupt_out_busy) {
 462                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 463         }
 464         tower_abort_transfers (dev);
 465         dev->open_count = 0;
 466
 467 unlock_exit:
 468         up (&dev->sem);
 469
 470 exit:
 471         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 472         return retval;
 473 }
 474
 475
 476 /**
 477  *      tower_abort_transfers
 478  *      aborts transfers and frees associated data structures
 479  */
 480 static void tower_abort_transfers (struct lego_usb_tower *dev)
 481 {
 482         dbg(2, "%s: enter", __FUNCTION__);
 483
 484         if (dev == NULL) {
 485                 dbg(1, "%s: dev is null", __FUNCTION__);
 486                 goto exit;
 487         }
 488
 489         /* shutdown transfer */
 490         if (dev->interrupt_in_running) {
 491                 dev->interrupt_in_running = 0;
 492                 mb();
 493                 if (dev->udev)
 494                         usb_kill_urb (dev->interrupt_in_urb);
 495         }
 496         if (dev->interrupt_out_busy && dev->udev)
 497                 usb_kill_urb(dev->interrupt_out_urb);
 498
 499 exit:
 500         dbg(2, "%s: leave", __FUNCTION__);
 501 }
 502
 503
 504 /**
 505  *      tower_check_for_read_packet
 506  *
 507  *      To get correct semantics for signals and non-blocking I/O
 508  *      with packetizing we pretend not to see any data in the read buffer
 509  *      until it has been there unchanged for at least
 510  *      dev->packet_timeout_jiffies, or until the buffer is full.
 511  */
 512 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
 513 {
 514         spin_lock_irq (&dev->read_buffer_lock);
 515         if (!packet_timeout
 516             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
 517             || dev->read_buffer_length == read_buffer_size) {
 518                 dev->read_packet_length = dev->read_buffer_length;
 519         }
 520         dev->interrupt_in_done = 0;
 521         spin_unlock_irq (&dev->read_buffer_lock);
 522 }
 523
 524
 525 /**
 526  *      tower_poll
 527  */
 528 static unsigned int tower_poll (struct file *file, poll_table *wait)
 529 {
 530         struct lego_usb_tower *dev;
 531         unsigned int mask = 0;
 532
 533         dbg(2, "%s: enter", __FUNCTION__);
 534
 535         dev = file->private_data;
 536
 537         poll_wait(file, &dev->read_wait, wait);
 538         poll_wait(file, &dev->write_wait, wait);
 539
 540         tower_check_for_read_packet(dev);
 541         if (dev->read_packet_length > 0) {
 542                 mask |= POLLIN | POLLRDNORM;
 543         }
 544         if (!dev->interrupt_out_busy) {
 545                 mask |= POLLOUT | POLLWRNORM;
 546         }
 547
 548         dbg(2, "%s: leave, mask = %d", __FUNCTION__, mask);
 549
 550         return mask;
 551 }
 552
 553
 554 /**
 555  *      tower_llseek
 556  */
 557 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
 558 {
 559         return -ESPIPE;         /* unseekable */
 560 }
 561
 562
 563 /**
 564  *      tower_read
 565  */
 566 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 567 {
 568         struct lego_usb_tower *dev;
 569         size_t bytes_to_read;
 570         int i;
 571         int retval = 0;
 572         unsigned long timeout = 0;
 573
 574         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 575
 576         dev = (struct lego_usb_tower *)file->private_data;
 577
 578         /* lock this object */
 579         if (down_interruptible (&dev->sem)) {
 580                 retval = -ERESTARTSYS;
 581                 goto exit;
 582         }
 583
 584         /* verify that the device wasn't unplugged */
 585         if (dev->udev == NULL) {
 586                 retval = -ENODEV;
 587                 err("No device or device unplugged %d", retval);
 588                 goto unlock_exit;
 589         }
 590
 591         /* verify that we actually have some data to read */
 592         if (count == 0) {
 593                 dbg(1, "%s: read request of 0 bytes", __FUNCTION__);
 594                 goto unlock_exit;
 595         }
 596
 597         if (read_timeout) {
 598                 timeout = jiffies + read_timeout * HZ / 1000;
 599         }
 600
 601         /* wait for data */
 602         tower_check_for_read_packet (dev);
 603         while (dev->read_packet_length == 0) {
 604                 if (file->f_flags & O_NONBLOCK) {
 605                         retval = -EAGAIN;
 606                         goto unlock_exit;
 607                 }
 608                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
 609                 if (retval < 0) {
 610                         goto unlock_exit;
 611                 }
 612
 613                 /* reset read timeout during read or write activity */
 614                 if (read_timeout
 615                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
 616                         timeout = jiffies + read_timeout * HZ / 1000;
 617                 }
 618                 /* check for read timeout */
 619                 if (read_timeout && time_after (jiffies, timeout)) {
 620                         retval = -ETIMEDOUT;
 621                         goto unlock_exit;
 622                 }
 623                 tower_check_for_read_packet (dev);
 624         }
 625
 626         /* copy the data from read_buffer into userspace */
 627         bytes_to_read = min(count, dev->read_packet_length);
 628
 629         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
 630                 retval = -EFAULT;
 631                 goto unlock_exit;
 632         }
 633
 634         spin_lock_irq (&dev->read_buffer_lock);
 635         dev->read_buffer_length -= bytes_to_read;
 636         dev->read_packet_length -= bytes_to_read;
 637         for (i=0; i<dev->read_buffer_length; i++) {
 638                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
 639         }
 640         spin_unlock_irq (&dev->read_buffer_lock);
 641
 642         retval = bytes_to_read;
 643
 644 unlock_exit:
 645         /* unlock the device */
 646         up (&dev->sem);
 647
 648 exit:
 649         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 650         return retval;
 651 }
 652
 653
 654 /**
 655  *      tower_write
 656  */
 657 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 658 {
 659         struct lego_usb_tower *dev;
 660         size_t bytes_to_write;
 661         int retval = 0;
 662
 663         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 664
 665         dev = (struct lego_usb_tower *)file->private_data;
 666
 667         /* lock this object */
 668         if (down_interruptible (&dev->sem)) {
 669                 retval = -ERESTARTSYS;
 670                 goto exit;
 671         }
 672
 673         /* verify that the device wasn't unplugged */
 674         if (dev->udev == NULL) {
 675                 retval = -ENODEV;
 676                 err("No device or device unplugged %d", retval);
 677                 goto unlock_exit;
 678         }
 679
 680         /* verify that we actually have some data to write */
 681         if (count == 0) {
 682                 dbg(1, "%s: write request of 0 bytes", __FUNCTION__);
 683                 goto unlock_exit;
 684         }
 685
 686         /* wait until previous transfer is finished */
 687         while (dev->interrupt_out_busy) {
 688                 if (file->f_flags & O_NONBLOCK) {
 689                         retval = -EAGAIN;
 690                         goto unlock_exit;
 691                 }
 692                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
 693                 if (retval) {
 694                         goto unlock_exit;
 695                 }
 696         }
 697
 698         /* write the data into interrupt_out_buffer from userspace */
 699         bytes_to_write = min_t(int, count, write_buffer_size);
 700         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __FUNCTION__, count, bytes_to_write);
 701
 702         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 703                 retval = -EFAULT;
 704                 goto unlock_exit;
 705         }
 706
 707         /* send off the urb */
 708         usb_fill_int_urb(dev->interrupt_out_urb,
 709                          dev->udev,
 710                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 711                          dev->interrupt_out_buffer,
 712                          bytes_to_write,
 713                          tower_interrupt_out_callback,
 714                          dev,
 715                          dev->interrupt_out_interval);
 716
 717         dev->interrupt_out_busy = 1;
 718         wmb();
 719
 720         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
 721         if (retval) {
 722                 dev->interrupt_out_busy = 0;
 723                 err("Couldn't submit interrupt_out_urb %d", retval);
 724                 goto unlock_exit;
 725         }
 726         retval = bytes_to_write;
 727
 728 unlock_exit:
 729         /* unlock the device */
 730         up (&dev->sem);
 731
 732 exit:
 733         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 734
 735         return retval;
 736 }
 737
 738
 739 /**
 740  *      tower_interrupt_in_callback
 741  */
 742 static void tower_interrupt_in_callback (struct urb *urb)
 743 {
 744         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 745         int status = urb->status;
 746         int retval;
 747
 748         dbg(4, "%s: enter, status %d", __FUNCTION__, status);
 749
 750         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 751
 752         if (status) {
 753                 if (status == -ENOENT ||
 754                     status == -ECONNRESET ||
 755                     status == -ESHUTDOWN) {
 756                         goto exit;
 757                 } else {
 758                         dbg(1, "%s: nonzero status received: %d", __FUNCTION__, status);
 759                         goto resubmit; /* maybe we can recover */
 760                 }
 761         }
 762
 763         if (urb->actual_length > 0) {
 764                 spin_lock (&dev->read_buffer_lock);
 765                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
 766                         memcpy (dev->read_buffer + dev->read_buffer_length,
 767                                 dev->interrupt_in_buffer,
 768                                 urb->actual_length);
 769                         dev->read_buffer_length += urb->actual_length;
 770                         dev->read_last_arrival = jiffies;
 771                         dbg(3, "%s: received %d bytes", __FUNCTION__, urb->actual_length);
 772                 } else {
 773                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __FUNCTION__, urb->actual_length);
 774                 }
 775                 spin_unlock (&dev->read_buffer_lock);
 776         }
 777
 778 resubmit:
 779         /* resubmit if we're still running */
 780         if (dev->interrupt_in_running && dev->udev) {
 781                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
 782                 if (retval) {
 783                         err("%s: usb_submit_urb failed (%d)", __FUNCTION__, retval);
 784                 }
 785         }
 786
 787 exit:
 788         dev->interrupt_in_done = 1;
 789         wake_up_interruptible (&dev->read_wait);
 790
 791         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 792         dbg(4, "%s: leave, status %d", __FUNCTION__, status);
 793 }
 794
 795
 796 /**
 797  *      tower_interrupt_out_callback
 798  */
 799 static void tower_interrupt_out_callback (struct urb *urb)
 800 {
 801         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 802         int status = urb->status;
 803
 804         dbg(4, "%s: enter, status %d", __FUNCTION__, status);
 805         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 806
 807         /* sync/async unlink faults aren't errors */
 808         if (status && !(status == -ENOENT ||
 809                         status == -ECONNRESET ||
 810                         status == -ESHUTDOWN)) {
 811                 dbg(1, "%s - nonzero write bulk status received: %d",
 812                     __FUNCTION__, status);
 813         }
 814
 815         dev->interrupt_out_busy = 0;
 816         wake_up_interruptible(&dev->write_wait);
 817
 818         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 819         dbg(4, "%s: leave, status %d", __FUNCTION__, status);
 820 }
 821
 822
 823 /**
 824  *      tower_probe
 825  *
 826  *      Called by the usb core when a new device is connected that it thinks
 827  *      this driver might be interested in.
 828  */
 829 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
 830 {
 831         struct usb_device *udev = interface_to_usbdev(interface);
 832         struct lego_usb_tower *dev = NULL;
 833         struct usb_host_interface *iface_desc;
 834         struct usb_endpoint_descriptor* endpoint;
 835         struct tower_get_version_reply get_version_reply;
 836         int i;
 837         int retval = -ENOMEM;
 838         int result;
 839
 840         dbg(2, "%s: enter", __FUNCTION__);
 841
 842         if (udev == NULL) {
 843                 info ("udev is NULL.");
 844         }
 845
 846         /* allocate memory for our device state and initialize it */
 847
 848         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
 849
 850         if (dev == NULL) {
 851                 err ("Out of memory");
 852                 goto exit;
 853         }
 854
 855         init_MUTEX (&dev->sem);
 856
 857         dev->udev = udev;
 858         dev->open_count = 0;
 859
 860         dev->read_buffer = NULL;
 861         dev->read_buffer_length = 0;
 862         dev->read_packet_length = 0;
 863         spin_lock_init (&dev->read_buffer_lock);
 864         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
 865         dev->read_last_arrival = jiffies;
 866
 867         init_waitqueue_head (&dev->read_wait);
 868         init_waitqueue_head (&dev->write_wait);
 869
 870         dev->interrupt_in_buffer = NULL;
 871         dev->interrupt_in_endpoint = NULL;
 872         dev->interrupt_in_urb = NULL;
 873         dev->interrupt_in_running = 0;
 874         dev->interrupt_in_done = 0;
 875
 876         dev->interrupt_out_buffer = NULL;
 877         dev->interrupt_out_endpoint = NULL;
 878         dev->interrupt_out_urb = NULL;
 879         dev->interrupt_out_busy = 0;
 880
 881         iface_desc = interface->cur_altsetting;
 882
 883         /* set up the endpoint information */
 884         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 885                 endpoint = &iface_desc->endpoint[i].desc;
 886
 887                 if (usb_endpoint_xfer_int(endpoint)) {
 888                         if (usb_endpoint_dir_in(endpoint))
 889                                 dev->interrupt_in_endpoint = endpoint;
 890                         else
 891                                 dev->interrupt_out_endpoint = endpoint;
 892                 }
 893         }
 894         if(dev->interrupt_in_endpoint == NULL) {
 895                 err("interrupt in endpoint not found");
 896                 goto error;
 897         }
 898         if (dev->interrupt_out_endpoint == NULL) {
 899                 err("interrupt out endpoint not found");
 900                 goto error;
 901         }
 902
 903         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
 904         if (!dev->read_buffer) {
 905                 err("Couldn't allocate read_buffer");
 906                 goto error;
 907         }
 908         dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
 909         if (!dev->interrupt_in_buffer) {
 910                 err("Couldn't allocate interrupt_in_buffer");
 911                 goto error;
 912         }
 913         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 914         if (!dev->interrupt_in_urb) {
 915                 err("Couldn't allocate interrupt_in_urb");
 916                 goto error;
 917         }
 918         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
 919         if (!dev->interrupt_out_buffer) {
 920                 err("Couldn't allocate interrupt_out_buffer");
 921                 goto error;
 922         }
 923         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 924         if (!dev->interrupt_out_urb) {
 925                 err("Couldn't allocate interrupt_out_urb");
 926                 goto error;
 927         }
 928         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 929         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 930
 931         /* we can register the device now, as it is ready */
 932         usb_set_intfdata (interface, dev);
 933
 934         retval = usb_register_dev (interface, &tower_class);
 935
 936         if (retval) {
 937                 /* something prevented us from registering this driver */
 938                 err ("Not able to get a minor for this device.");
 939                 usb_set_intfdata (interface, NULL);
 940                 goto error;
 941         }
 942         dev->minor = interface->minor;
 943
 944         /* let the user know what node this device is now attached to */
 945         info ("LEGO USB Tower #%d now attached to major %d minor %d", (dev->minor - LEGO_USB_TOWER_MINOR_BASE), USB_MAJOR, dev->minor);
 946
 947         /* get the firmware version and log it */
 948         result = usb_control_msg (udev,
 949                                   usb_rcvctrlpipe(udev, 0),
 950                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
 951                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 952                                   0,
 953                                   0,
 954                                   &get_version_reply,
 955                                   sizeof(get_version_reply),
 956                                   1000);
 957         if (result < 0) {
 958                 err("LEGO USB Tower get version control request failed");
 959                 retval = result;
 960                 goto error;
 961         }
 962         info("LEGO USB Tower firmware version is %d.%d build %d",
 963              get_version_reply.major,
 964              get_version_reply.minor,
 965              le16_to_cpu(get_version_reply.build_no));
 966
 967
 968 exit:
 969         dbg(2, "%s: leave, return value 0x%.8lx (dev)", __FUNCTION__, (long) dev);
 970
 971         return retval;
 972
 973 error:
 974         tower_delete(dev);
 975         return retval;
 976 }
 977
 978
 979 /**
 980  *      tower_disconnect
 981  *
 982  *      Called by the usb core when the device is removed from the system.
 983  */
 984 static void tower_disconnect (struct usb_interface *interface)
 985 {
 986         struct lego_usb_tower *dev;
 987         int minor;
 988
 989         dbg(2, "%s: enter", __FUNCTION__);
 990
 991         dev = usb_get_intfdata (interface);
 992         usb_set_intfdata (interface, NULL);
 993
 994         minor = dev->minor;
 995
 996         /* give back our minor */
 997         usb_deregister_dev (interface, &tower_class);
 998
 999         down (&dev->sem);
1000
1001         /* if the device is not opened, then we clean up right now */
1002         if (!dev->open_count) {
1003                 up (&dev->sem);
1004                 tower_delete (dev);
1005         } else {
1006                 dev->udev = NULL;
1007                 up (&dev->sem);
1008         }
1009
1010         info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));
1011
1012         dbg(2, "%s: leave", __FUNCTION__);
1013 }
1014
1015
1016
1017 /**
1018  *      lego_usb_tower_init
1019  */
1020 static int __init lego_usb_tower_init(void)
1021 {
1022         int result;
1023         int retval = 0;
1024
1025         dbg(2, "%s: enter", __FUNCTION__);
1026
1027         /* register this driver with the USB subsystem */
1028         result = usb_register(&tower_driver);
1029         if (result < 0) {
1030                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1031                 retval = -1;
1032                 goto exit;
1033         }
1034
1035         info(DRIVER_DESC " " DRIVER_VERSION);
1036
1037 exit:
1038         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
1039
1040         return retval;
1041 }
1042
1043
1044 /**
1045  *      lego_usb_tower_exit
1046  */
1047 static void __exit lego_usb_tower_exit(void)
1048 {
1049         dbg(2, "%s: enter", __FUNCTION__);
1050
1051         /* deregister this driver with the USB subsystem */
1052         usb_deregister (&tower_driver);
1053
1054         dbg(2, "%s: leave", __FUNCTION__);
1055 }
1056
1057 module_init (lego_usb_tower_init);
1058 module_exit (lego_usb_tower_exit);
1059
1060 MODULE_AUTHOR(DRIVER_AUTHOR);
1061 MODULE_DESCRIPTION(DRIVER_DESC);
1062 #ifdef MODULE_LICENSE
1063 MODULE_LICENSE("GPL");
1064 #endif