git.oblomov.eu Git - linux-2.6/blob - drivers/usb/misc/legousbtower.c

   1 /*
   2  * LEGO USB Tower driver
   3  *
   4  * Copyright (C) 2003 David Glance <davidgsf@sourceforge.net>
   5  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License as
   9  *      published by the Free Software Foundation; either version 2 of
  10  *      the License, or (at your option) any later version.
  11  *
  12  * derived from USB Skeleton driver - 0.5
  13  * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
  14  *
  15  * History:
  16  *
  17  * 2001-10-13 - 0.1 js
  18  *   - first version
  19  * 2001-11-03 - 0.2 js
  20  *   - simplified buffering, one-shot URBs for writing
  21  * 2001-11-10 - 0.3 js
  22  *   - removed IOCTL (setting power/mode is more complicated, postponed)
  23  * 2001-11-28 - 0.4 js
  24  *   - added vendor commands for mode of operation and power level in open
  25  * 2001-12-04 - 0.5 js
  26  *   - set IR mode by default (by oversight 0.4 set VLL mode)
  27  * 2002-01-11 - 0.5? pcchan
  28  *   - make read buffer reusable and work around bytes_to_write issue between
  29  *     uhci and legusbtower
  30  * 2002-09-23 - 0.52 david (david@csse.uwa.edu.au)
  31  *   - imported into lejos project
  32  *   - changed wake_up to wake_up_interruptible
  33  *   - changed to use lego0 rather than tower0
  34  *   - changed dbg() to use __func__ rather than deprecated __FUNCTION__
  35  * 2003-01-12 - 0.53 david (david@csse.uwa.edu.au)
  36  *   - changed read and write to write everything or
  37  *     timeout (from a patch by Chris Riesen and Brett Thaeler driver)
  38  *   - added ioctl functionality to set timeouts
  39  * 2003-07-18 - 0.54 davidgsf (david@csse.uwa.edu.au)
  40  *   - initial import into LegoUSB project
  41  *   - merge of existing LegoUSB.c driver
  42  * 2003-07-18 - 0.56 davidgsf (david@csse.uwa.edu.au)
  43  *   - port to 2.6 style driver
  44  * 2004-02-29 - 0.6 Juergen Stuber <starblue@users.sourceforge.net>
  45  *   - fix locking
  46  *   - unlink read URBs which are no longer needed
  47  *   - allow increased buffer size, eliminates need for timeout on write
  48  *   - have read URB running continuously
  49  *   - added poll
  50  *   - forbid seeking
  51  *   - added nonblocking I/O
  52  *   - changed back __func__ to __FUNCTION__
  53  *   - read and log tower firmware version
  54  *   - reset tower on probe, avoids failure of first write
  55  * 2004-03-09 - 0.7 Juergen Stuber <starblue@users.sourceforge.net>
  56  *   - timeout read now only after inactivity, shorten default accordingly
  57  * 2004-03-11 - 0.8 Juergen Stuber <starblue@users.sourceforge.net>
  58  *   - log major, minor instead of possibly confusing device filename
  59  *   - whitespace cleanup
  60  * 2004-03-12 - 0.9 Juergen Stuber <starblue@users.sourceforge.net>
  61  *   - normalize whitespace in debug messages
  62  *   - take care about endianness in control message responses
  63  * 2004-03-13 - 0.91 Juergen Stuber <starblue@users.sourceforge.net>
  64  *   - make default intervals longer to accommodate current EHCI driver
  65  * 2004-03-19 - 0.92 Juergen Stuber <starblue@users.sourceforge.net>
  66  *   - replaced atomic_t by memory barriers
  67  * 2004-04-21 - 0.93 Juergen Stuber <starblue@users.sourceforge.net>
  68  *   - wait for completion of write urb in release (needed for remotecontrol)
  69  *   - corrected poll for write direction (missing negation)
  70  * 2004-04-22 - 0.94 Juergen Stuber <starblue@users.sourceforge.net>
  71  *   - make device locking interruptible
  72  * 2004-04-30 - 0.95 Juergen Stuber <starblue@users.sourceforge.net>
  73  *   - check for valid udev on resubmitting and unlinking urbs
  74  * 2004-08-03 - 0.96 Juergen Stuber <starblue@users.sourceforge.net>
  75  *   - move reset into open to clean out spurious data
  76  */
  77
  78 #include <linux/config.h>
  79 #include <linux/kernel.h>
  80 #include <linux/errno.h>
  81 #include <linux/init.h>
  82 #include <linux/slab.h>
  83 #include <linux/module.h>
  84 #include <linux/smp_lock.h>
  85 #include <linux/completion.h>
  86 #include <asm/uaccess.h>
  87 #include <linux/usb.h>
  88 #include <linux/poll.h>
  89
  90
  91 #ifdef CONFIG_USB_DEBUG
  92         static int debug = 4;
  93 #else
  94         static int debug = 0;
  95 #endif
  96
  97 /* Use our own dbg macro */
  98 #undef dbg
  99 #define dbg(lvl, format, arg...) do { if (debug >= lvl) printk(KERN_DEBUG  __FILE__ ": " format "\n", ## arg); } while (0)
 100
 101
 102 /* Version Information */
 103 #define DRIVER_VERSION "v0.96"
 104 #define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
 105 #define DRIVER_DESC "LEGO USB Tower Driver"
 106
 107 /* Module parameters */
 108 module_param(debug, int, S_IRUGO | S_IWUSR);
 109 MODULE_PARM_DESC(debug, "Debug enabled or not");
 110
 111 /* The defaults are chosen to work with the latest versions of leJOS and NQC.
 112  */
 113
 114 /* Some legacy software likes to receive packets in one piece.
 115  * In this case read_buffer_size should exceed the maximal packet length
 116  * (417 for datalog uploads), and packet_timeout should be set.
 117  */
 118 static int read_buffer_size = 480;
 119 module_param(read_buffer_size, int, 0);
 120 MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
 121
 122 /* Some legacy software likes to send packets in one piece.
 123  * In this case write_buffer_size should exceed the maximal packet length
 124  * (417 for firmware and program downloads).
 125  * A problem with long writes is that the following read may time out
 126  * if the software is not prepared to wait long enough.
 127  */
 128 static int write_buffer_size = 480;
 129 module_param(write_buffer_size, int, 0);
 130 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 131
 132 /* Some legacy software expects reads to contain whole LASM packets.
 133  * To achieve this, characters which arrive before a packet timeout
 134  * occurs will be returned in a single read operation.
 135  * A problem with long reads is that the software may time out
 136  * if it is not prepared to wait long enough.
 137  * The packet timeout should be greater than the time between the
 138  * reception of subsequent characters, which should arrive about
 139  * every 5ms for the standard 2400 baud.
 140  * Set it to 0 to disable.
 141  */
 142 static int packet_timeout = 50;
 143 module_param(packet_timeout, int, 0);
 144 MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
 145
 146 /* Some legacy software expects blocking reads to time out.
 147  * Timeout occurs after the specified time of read and write inactivity.
 148  * Set it to 0 to disable.
 149  */
 150 static int read_timeout = 200;
 151 module_param(read_timeout, int, 0);
 152 MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
 153
 154 /* As of kernel version 2.6.4 ehci-hcd uses an
 155  * "only one interrupt transfer per frame" shortcut
 156  * to simplify the scheduling of periodic transfers.
 157  * This conflicts with our standard 1ms intervals for in and out URBs.
 158  * We use default intervals of 2ms for in and 8ms for out transfers,
 159  * which is fast enough for 2400 baud and allows a small additional load.
 160  * Increase the interval to allow more devices that do interrupt transfers,
 161  * or set to 0 to use the standard interval from the endpoint descriptors.
 162  */
 163 static int interrupt_in_interval = 2;
 164 module_param(interrupt_in_interval, int, 0);
 165 MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
 166
 167 static int interrupt_out_interval = 8;
 168 module_param(interrupt_out_interval, int, 0);
 169 MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
 170
 171 /* Define these values to match your device */
 172 #define LEGO_USB_TOWER_VENDOR_ID        0x0694
 173 #define LEGO_USB_TOWER_PRODUCT_ID       0x0001
 174
 175 /* Vendor requests */
 176 #define LEGO_USB_TOWER_REQUEST_RESET            0x04
 177 #define LEGO_USB_TOWER_REQUEST_GET_VERSION      0xFD
 178
 179 struct tower_reset_reply {
 180         __le16 size;            /* little-endian */
 181         __u8 err_code;
 182         __u8 spare;
 183 } __attribute__ ((packed));
 184
 185 struct tower_get_version_reply {
 186         __le16 size;            /* little-endian */
 187         __u8 err_code;
 188         __u8 spare;
 189         __u8 major;
 190         __u8 minor;
 191         __le16 build_no;                /* little-endian */
 192 } __attribute__ ((packed));
 193
 194
 195 /* table of devices that work with this driver */
 196 static struct usb_device_id tower_table [] = {
 197         { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
 198         { }                                     /* Terminating entry */
 199 };
 200
 201 MODULE_DEVICE_TABLE (usb, tower_table);
 202
 203 #define LEGO_USB_TOWER_MINOR_BASE       160
 204
 205
 206 /* Structure to hold all of our device specific stuff */
 207 struct lego_usb_tower {
 208         struct semaphore        sem;            /* locks this structure */
 209         struct usb_device*      udev;           /* save off the usb device pointer */
 210         unsigned char           minor;          /* the starting minor number for this device */
 211
 212         int                     open_count;     /* number of times this port has been opened */
 213
 214         char*                   read_buffer;
 215         size_t                  read_buffer_length; /* this much came in */
 216         size_t                  read_packet_length; /* this much will be returned on read */
 217         spinlock_t              read_buffer_lock;
 218         int                     packet_timeout_jiffies;
 219         unsigned long           read_last_arrival;
 220
 221         wait_queue_head_t       read_wait;
 222         wait_queue_head_t       write_wait;
 223
 224         char*                   interrupt_in_buffer;
 225         struct usb_endpoint_descriptor* interrupt_in_endpoint;
 226         struct urb*             interrupt_in_urb;
 227         int                     interrupt_in_interval;
 228         int                     interrupt_in_running;
 229         int                     interrupt_in_done;
 230
 231         char*                   interrupt_out_buffer;
 232         struct usb_endpoint_descriptor* interrupt_out_endpoint;
 233         struct urb*             interrupt_out_urb;
 234         int                     interrupt_out_interval;
 235         int                     interrupt_out_busy;
 236
 237 };
 238
 239
 240 /* local function prototypes */
 241 static ssize_t tower_read       (struct file *file, char __user *buffer, size_t count, loff_t *ppos);
 242 static ssize_t tower_write      (struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
 243 static inline void tower_delete (struct lego_usb_tower *dev);
 244 static int tower_open           (struct inode *inode, struct file *file);
 245 static int tower_release        (struct inode *inode, struct file *file);
 246 static unsigned int tower_poll  (struct file *file, poll_table *wait);
 247 static loff_t tower_llseek      (struct file *file, loff_t off, int whence);
 248
 249 static void tower_abort_transfers (struct lego_usb_tower *dev);
 250 static void tower_check_for_read_packet (struct lego_usb_tower *dev);
 251 static void tower_interrupt_in_callback (struct urb *urb, struct pt_regs *regs);
 252 static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs);
 253
 254 static int  tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
 255 static void tower_disconnect    (struct usb_interface *interface);
 256
 257
 258 /* prevent races between open() and disconnect */
 259 static DECLARE_MUTEX (disconnect_sem);
 260
 261 /* file operations needed when we register this driver */
 262 static struct file_operations tower_fops = {
 263         .owner =        THIS_MODULE,
 264         .read  =        tower_read,
 265         .write =        tower_write,
 266         .open =         tower_open,
 267         .release =      tower_release,
 268         .poll =         tower_poll,
 269         .llseek =       tower_llseek,
 270 };
 271
 272 /*
 273  * usb class driver info in order to get a minor number from the usb core,
 274  * and to have the device registered with the driver core
 275  */
 276 static struct usb_class_driver tower_class = {
 277         .name =         "legousbtower%d",
 278         .fops =         &tower_fops,
 279         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
 280 };
 281
 282
 283 /* usb specific object needed to register this driver with the usb subsystem */
 284 static struct usb_driver tower_driver = {
 285         .owner =        THIS_MODULE,
 286         .name =         "legousbtower",
 287         .probe =        tower_probe,
 288         .disconnect =   tower_disconnect,
 289         .id_table =     tower_table,
 290 };
 291
 292
 293 /**
 294  *      lego_usb_tower_debug_data
 295  */
 296 static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
 297 {
 298         int i;
 299
 300         if (debug < level)
 301                 return;
 302
 303         printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
 304         for (i = 0; i < size; ++i) {
 305                 printk ("%.2x ", data[i]);
 306         }
 307         printk ("\n");
 308 }
 309
 310
 311 /**
 312  *      tower_delete
 313  */
 314 static inline void tower_delete (struct lego_usb_tower *dev)
 315 {
 316         dbg(2, "%s: enter", __FUNCTION__);
 317
 318         tower_abort_transfers (dev);
 319
 320         /* free data structures */
 321         if (dev->interrupt_in_urb != NULL) {
 322                 usb_free_urb (dev->interrupt_in_urb);
 323         }
 324         if (dev->interrupt_out_urb != NULL) {
 325                 usb_free_urb (dev->interrupt_out_urb);
 326         }
 327         kfree (dev->read_buffer);
 328         kfree (dev->interrupt_in_buffer);
 329         kfree (dev->interrupt_out_buffer);
 330         kfree (dev);
 331
 332         dbg(2, "%s: leave", __FUNCTION__);
 333 }
 334
 335
 336 /**
 337  *      tower_open
 338  */
 339 static int tower_open (struct inode *inode, struct file *file)
 340 {
 341         struct lego_usb_tower *dev = NULL;
 342         int subminor;
 343         int retval = 0;
 344         struct usb_interface *interface;
 345         struct tower_reset_reply reset_reply;
 346         int result;
 347
 348         dbg(2, "%s: enter", __FUNCTION__);
 349
 350         nonseekable_open(inode, file);
 351         subminor = iminor(inode);
 352
 353         down (&disconnect_sem);
 354
 355         interface = usb_find_interface (&tower_driver, subminor);
 356
 357         if (!interface) {
 358                 err ("%s - error, can't find device for minor %d",
 359                      __FUNCTION__, subminor);
 360                 retval = -ENODEV;
 361                 goto unlock_disconnect_exit;
 362         }
 363
 364         dev = usb_get_intfdata(interface);
 365
 366         if (!dev) {
 367                 retval = -ENODEV;
 368                 goto unlock_disconnect_exit;
 369         }
 370
 371         /* lock this device */
 372         if (down_interruptible (&dev->sem)) {
 373                 retval = -ERESTARTSYS;
 374                 goto unlock_disconnect_exit;
 375         }
 376
 377         /* allow opening only once */
 378         if (dev->open_count) {
 379                 retval = -EBUSY;
 380                 goto unlock_exit;
 381         }
 382         dev->open_count = 1;
 383
 384         /* reset the tower */
 385         result = usb_control_msg (dev->udev,
 386                                   usb_rcvctrlpipe(dev->udev, 0),
 387                                   LEGO_USB_TOWER_REQUEST_RESET,
 388                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 389                                   0,
 390                                   0,
 391                                   &reset_reply,
 392                                   sizeof(reset_reply),
 393                                   1000);
 394         if (result < 0) {
 395                 err("LEGO USB Tower reset control request failed");
 396                 retval = result;
 397                 goto unlock_exit;
 398         }
 399
 400         /* initialize in direction */
 401         dev->read_buffer_length = 0;
 402         dev->read_packet_length = 0;
 403         usb_fill_int_urb (dev->interrupt_in_urb,
 404                           dev->udev,
 405                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
 406                           dev->interrupt_in_buffer,
 407                           le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
 408                           tower_interrupt_in_callback,
 409                           dev,
 410                           dev->interrupt_in_interval);
 411
 412         dev->interrupt_in_running = 1;
 413         dev->interrupt_in_done = 0;
 414         mb();
 415
 416         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
 417         if (retval) {
 418                 err("Couldn't submit interrupt_in_urb %d", retval);
 419                 dev->interrupt_in_running = 0;
 420                 dev->open_count = 0;
 421                 goto unlock_exit;
 422         }
 423
 424         /* save device in the file's private structure */
 425         file->private_data = dev;
 426
 427 unlock_exit:
 428         up (&dev->sem);
 429
 430 unlock_disconnect_exit:
 431         up (&disconnect_sem);
 432
 433         dbg(2, "%s: leave, return value %d ", __FUNCTION__, retval);
 434
 435         return retval;
 436 }
 437
 438 /**
 439  *      tower_release
 440  */
 441 static int tower_release (struct inode *inode, struct file *file)
 442 {
 443         struct lego_usb_tower *dev;
 444         int retval = 0;
 445
 446         dbg(2, "%s: enter", __FUNCTION__);
 447
 448         dev = (struct lego_usb_tower *)file->private_data;
 449
 450         if (dev == NULL) {
 451                 dbg(1, "%s: object is NULL", __FUNCTION__);
 452                 retval = -ENODEV;
 453                 goto exit;
 454         }
 455
 456         if (down_interruptible (&dev->sem)) {
 457                 retval = -ERESTARTSYS;
 458                 goto exit;
 459         }
 460
 461         if (dev->open_count != 1) {
 462                 dbg(1, "%s: device not opened exactly once", __FUNCTION__);
 463                 retval = -ENODEV;
 464                 goto unlock_exit;
 465         }
 466         if (dev->udev == NULL) {
 467                 /* the device was unplugged before the file was released */
 468                 up (&dev->sem); /* unlock here as tower_delete frees dev */
 469                 tower_delete (dev);
 470                 goto exit;
 471         }
 472
 473         /* wait until write transfer is finished */
 474         if (dev->interrupt_out_busy) {
 475                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 476         }
 477         tower_abort_transfers (dev);
 478         dev->open_count = 0;
 479
 480 unlock_exit:
 481         up (&dev->sem);
 482
 483 exit:
 484         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 485         return retval;
 486 }
 487
 488
 489 /**
 490  *      tower_abort_transfers
 491  *      aborts transfers and frees associated data structures
 492  */
 493 static void tower_abort_transfers (struct lego_usb_tower *dev)
 494 {
 495         dbg(2, "%s: enter", __FUNCTION__);
 496
 497         if (dev == NULL) {
 498                 dbg(1, "%s: dev is null", __FUNCTION__);
 499                 goto exit;
 500         }
 501
 502         /* shutdown transfer */
 503         if (dev->interrupt_in_running) {
 504                 dev->interrupt_in_running = 0;
 505                 mb();
 506                 if (dev->interrupt_in_urb != NULL && dev->udev) {
 507                         usb_kill_urb (dev->interrupt_in_urb);
 508                 }
 509         }
 510         if (dev->interrupt_out_busy) {
 511                 if (dev->interrupt_out_urb != NULL && dev->udev) {
 512                         usb_kill_urb (dev->interrupt_out_urb);
 513                 }
 514         }
 515
 516 exit:
 517         dbg(2, "%s: leave", __FUNCTION__);
 518 }
 519
 520
 521 /**
 522  *      tower_check_for_read_packet
 523  *
 524  *      To get correct semantics for signals and non-blocking I/O
 525  *      with packetizing we pretend not to see any data in the read buffer
 526  *      until it has been there unchanged for at least
 527  *      dev->packet_timeout_jiffies, or until the buffer is full.
 528  */
 529 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
 530 {
 531         spin_lock_irq (&dev->read_buffer_lock);
 532         if (!packet_timeout
 533             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
 534             || dev->read_buffer_length == read_buffer_size) {
 535                 dev->read_packet_length = dev->read_buffer_length;
 536         }
 537         dev->interrupt_in_done = 0;
 538         spin_unlock_irq (&dev->read_buffer_lock);
 539 }
 540
 541
 542 /**
 543  *      tower_poll
 544  */
 545 static unsigned int tower_poll (struct file *file, poll_table *wait)
 546 {
 547         struct lego_usb_tower *dev;
 548         unsigned int mask = 0;
 549
 550         dbg(2, "%s: enter", __FUNCTION__);
 551
 552         dev = file->private_data;
 553
 554         poll_wait(file, &dev->read_wait, wait);
 555         poll_wait(file, &dev->write_wait, wait);
 556
 557         tower_check_for_read_packet(dev);
 558         if (dev->read_packet_length > 0) {
 559                 mask |= POLLIN | POLLRDNORM;
 560         }
 561         if (!dev->interrupt_out_busy) {
 562                 mask |= POLLOUT | POLLWRNORM;
 563         }
 564
 565         dbg(2, "%s: leave, mask = %d", __FUNCTION__, mask);
 566
 567         return mask;
 568 }
 569
 570
 571 /**
 572  *      tower_llseek
 573  */
 574 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
 575 {
 576         return -ESPIPE;         /* unseekable */
 577 }
 578
 579
 580 /**
 581  *      tower_read
 582  */
 583 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 584 {
 585         struct lego_usb_tower *dev;
 586         size_t bytes_to_read;
 587         int i;
 588         int retval = 0;
 589         unsigned long timeout = 0;
 590
 591         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 592
 593         dev = (struct lego_usb_tower *)file->private_data;
 594
 595         /* lock this object */
 596         if (down_interruptible (&dev->sem)) {
 597                 retval = -ERESTARTSYS;
 598                 goto exit;
 599         }
 600
 601         /* verify that the device wasn't unplugged */
 602         if (dev->udev == NULL) {
 603                 retval = -ENODEV;
 604                 err("No device or device unplugged %d", retval);
 605                 goto unlock_exit;
 606         }
 607
 608         /* verify that we actually have some data to read */
 609         if (count == 0) {
 610                 dbg(1, "%s: read request of 0 bytes", __FUNCTION__);
 611                 goto unlock_exit;
 612         }
 613
 614         if (read_timeout) {
 615                 timeout = jiffies + read_timeout * HZ / 1000;
 616         }
 617
 618         /* wait for data */
 619         tower_check_for_read_packet (dev);
 620         while (dev->read_packet_length == 0) {
 621                 if (file->f_flags & O_NONBLOCK) {
 622                         retval = -EAGAIN;
 623                         goto unlock_exit;
 624                 }
 625                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
 626                 if (retval < 0) {
 627                         goto unlock_exit;
 628                 }
 629
 630                 /* reset read timeout during read or write activity */
 631                 if (read_timeout
 632                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
 633                         timeout = jiffies + read_timeout * HZ / 1000;
 634                 }
 635                 /* check for read timeout */
 636                 if (read_timeout && time_after (jiffies, timeout)) {
 637                         retval = -ETIMEDOUT;
 638                         goto unlock_exit;
 639                 }
 640                 tower_check_for_read_packet (dev);
 641         }
 642
 643         /* copy the data from read_buffer into userspace */
 644         bytes_to_read = min(count, dev->read_packet_length);
 645
 646         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
 647                 retval = -EFAULT;
 648                 goto unlock_exit;
 649         }
 650
 651         spin_lock_irq (&dev->read_buffer_lock);
 652         dev->read_buffer_length -= bytes_to_read;
 653         dev->read_packet_length -= bytes_to_read;
 654         for (i=0; i<dev->read_buffer_length; i++) {
 655                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
 656         }
 657         spin_unlock_irq (&dev->read_buffer_lock);
 658
 659         retval = bytes_to_read;
 660
 661 unlock_exit:
 662         /* unlock the device */
 663         up (&dev->sem);
 664
 665 exit:
 666         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 667         return retval;
 668 }
 669
 670
 671 /**
 672  *      tower_write
 673  */
 674 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 675 {
 676         struct lego_usb_tower *dev;
 677         size_t bytes_to_write;
 678         int retval = 0;
 679
 680         dbg(2, "%s: enter, count = %Zd", __FUNCTION__, count);
 681
 682         dev = (struct lego_usb_tower *)file->private_data;
 683
 684         /* lock this object */
 685         if (down_interruptible (&dev->sem)) {
 686                 retval = -ERESTARTSYS;
 687                 goto exit;
 688         }
 689
 690         /* verify that the device wasn't unplugged */
 691         if (dev->udev == NULL) {
 692                 retval = -ENODEV;
 693                 err("No device or device unplugged %d", retval);
 694                 goto unlock_exit;
 695         }
 696
 697         /* verify that we actually have some data to write */
 698         if (count == 0) {
 699                 dbg(1, "%s: write request of 0 bytes", __FUNCTION__);
 700                 goto unlock_exit;
 701         }
 702
 703         /* wait until previous transfer is finished */
 704         while (dev->interrupt_out_busy) {
 705                 if (file->f_flags & O_NONBLOCK) {
 706                         retval = -EAGAIN;
 707                         goto unlock_exit;
 708                 }
 709                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
 710                 if (retval) {
 711                         goto unlock_exit;
 712                 }
 713         }
 714
 715         /* write the data into interrupt_out_buffer from userspace */
 716         bytes_to_write = min_t(int, count, write_buffer_size);
 717         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __FUNCTION__, count, bytes_to_write);
 718
 719         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 720                 retval = -EFAULT;
 721                 goto unlock_exit;
 722         }
 723
 724         /* send off the urb */
 725         usb_fill_int_urb(dev->interrupt_out_urb,
 726                          dev->udev,
 727                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 728                          dev->interrupt_out_buffer,
 729                          bytes_to_write,
 730                          tower_interrupt_out_callback,
 731                          dev,
 732                          dev->interrupt_out_interval);
 733
 734         dev->interrupt_out_busy = 1;
 735         wmb();
 736
 737         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
 738         if (retval) {
 739                 dev->interrupt_out_busy = 0;
 740                 err("Couldn't submit interrupt_out_urb %d", retval);
 741                 goto unlock_exit;
 742         }
 743         retval = bytes_to_write;
 744
 745 unlock_exit:
 746         /* unlock the device */
 747         up (&dev->sem);
 748
 749 exit:
 750         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
 751
 752         return retval;
 753 }
 754
 755
 756 /**
 757  *      tower_interrupt_in_callback
 758  */
 759 static void tower_interrupt_in_callback (struct urb *urb, struct pt_regs *regs)
 760 {
 761         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 762         int retval;
 763
 764         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
 765
 766         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 767
 768         if (urb->status) {
 769                 if (urb->status == -ENOENT ||
 770                     urb->status == -ECONNRESET ||
 771                     urb->status == -ESHUTDOWN) {
 772                         goto exit;
 773                 } else {
 774                         dbg(1, "%s: nonzero status received: %d", __FUNCTION__, urb->status);
 775                         goto resubmit; /* maybe we can recover */
 776                 }
 777         }
 778
 779         if (urb->actual_length > 0) {
 780                 spin_lock (&dev->read_buffer_lock);
 781                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
 782                         memcpy (dev->read_buffer + dev->read_buffer_length,
 783                                 dev->interrupt_in_buffer,
 784                                 urb->actual_length);
 785                         dev->read_buffer_length += urb->actual_length;
 786                         dev->read_last_arrival = jiffies;
 787                         dbg(3, "%s: received %d bytes", __FUNCTION__, urb->actual_length);
 788                 } else {
 789                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __FUNCTION__, urb->actual_length);
 790                 }
 791                 spin_unlock (&dev->read_buffer_lock);
 792         }
 793
 794 resubmit:
 795         /* resubmit if we're still running */
 796         if (dev->interrupt_in_running && dev->udev) {
 797                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
 798                 if (retval) {
 799                         err("%s: usb_submit_urb failed (%d)", __FUNCTION__, retval);
 800                 }
 801         }
 802
 803 exit:
 804         dev->interrupt_in_done = 1;
 805         wake_up_interruptible (&dev->read_wait);
 806
 807         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 808         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
 809 }
 810
 811
 812 /**
 813  *      tower_interrupt_out_callback
 814  */
 815 static void tower_interrupt_out_callback (struct urb *urb, struct pt_regs *regs)
 816 {
 817         struct lego_usb_tower *dev = (struct lego_usb_tower *)urb->context;
 818
 819         dbg(4, "%s: enter, status %d", __FUNCTION__, urb->status);
 820         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 821
 822         /* sync/async unlink faults aren't errors */
 823         if (urb->status && !(urb->status == -ENOENT ||
 824                              urb->status == -ECONNRESET ||
 825                              urb->status == -ESHUTDOWN)) {
 826                 dbg(1, "%s - nonzero write bulk status received: %d",
 827                     __FUNCTION__, urb->status);
 828         }
 829
 830         dev->interrupt_out_busy = 0;
 831         wake_up_interruptible(&dev->write_wait);
 832
 833         lego_usb_tower_debug_data(5, __FUNCTION__, urb->actual_length, urb->transfer_buffer);
 834         dbg(4, "%s: leave, status %d", __FUNCTION__, urb->status);
 835 }
 836
 837
 838 /**
 839  *      tower_probe
 840  *
 841  *      Called by the usb core when a new device is connected that it thinks
 842  *      this driver might be interested in.
 843  */
 844 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
 845 {
 846         struct usb_device *udev = interface_to_usbdev(interface);
 847         struct lego_usb_tower *dev = NULL;
 848         struct usb_host_interface *iface_desc;
 849         struct usb_endpoint_descriptor* endpoint;
 850         struct tower_get_version_reply get_version_reply;
 851         int i;
 852         int retval = -ENOMEM;
 853         int result;
 854
 855         dbg(2, "%s: enter", __FUNCTION__);
 856
 857         if (udev == NULL) {
 858                 info ("udev is NULL.");
 859         }
 860
 861         /* allocate memory for our device state and initialize it */
 862
 863         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
 864
 865         if (dev == NULL) {
 866                 err ("Out of memory");
 867                 goto exit;
 868         }
 869
 870         init_MUTEX (&dev->sem);
 871
 872         dev->udev = udev;
 873         dev->open_count = 0;
 874
 875         dev->read_buffer = NULL;
 876         dev->read_buffer_length = 0;
 877         dev->read_packet_length = 0;
 878         spin_lock_init (&dev->read_buffer_lock);
 879         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
 880         dev->read_last_arrival = jiffies;
 881
 882         init_waitqueue_head (&dev->read_wait);
 883         init_waitqueue_head (&dev->write_wait);
 884
 885         dev->interrupt_in_buffer = NULL;
 886         dev->interrupt_in_endpoint = NULL;
 887         dev->interrupt_in_urb = NULL;
 888         dev->interrupt_in_running = 0;
 889         dev->interrupt_in_done = 0;
 890
 891         dev->interrupt_out_buffer = NULL;
 892         dev->interrupt_out_endpoint = NULL;
 893         dev->interrupt_out_urb = NULL;
 894         dev->interrupt_out_busy = 0;
 895
 896         iface_desc = interface->cur_altsetting;
 897
 898         /* set up the endpoint information */
 899         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 900                 endpoint = &iface_desc->endpoint[i].desc;
 901
 902                 if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_IN) &&
 903                     ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
 904                         dev->interrupt_in_endpoint = endpoint;
 905                 }
 906
 907                 if (((endpoint->bEndpointAddress & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT) &&
 908                     ((endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) == USB_ENDPOINT_XFER_INT)) {
 909                         dev->interrupt_out_endpoint = endpoint;
 910                 }
 911         }
 912         if(dev->interrupt_in_endpoint == NULL) {
 913                 err("interrupt in endpoint not found");
 914                 goto error;
 915         }
 916         if (dev->interrupt_out_endpoint == NULL) {
 917                 err("interrupt out endpoint not found");
 918                 goto error;
 919         }
 920
 921         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
 922         if (!dev->read_buffer) {
 923                 err("Couldn't allocate read_buffer");
 924                 goto error;
 925         }
 926         dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
 927         if (!dev->interrupt_in_buffer) {
 928                 err("Couldn't allocate interrupt_in_buffer");
 929                 goto error;
 930         }
 931         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 932         if (!dev->interrupt_in_urb) {
 933                 err("Couldn't allocate interrupt_in_urb");
 934                 goto error;
 935         }
 936         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
 937         if (!dev->interrupt_out_buffer) {
 938                 err("Couldn't allocate interrupt_out_buffer");
 939                 goto error;
 940         }
 941         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 942         if (!dev->interrupt_out_urb) {
 943                 err("Couldn't allocate interrupt_out_urb");
 944                 goto error;
 945         }
 946         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 947         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 948
 949         /* we can register the device now, as it is ready */
 950         usb_set_intfdata (interface, dev);
 951
 952         retval = usb_register_dev (interface, &tower_class);
 953
 954         if (retval) {
 955                 /* something prevented us from registering this driver */
 956                 err ("Not able to get a minor for this device.");
 957                 usb_set_intfdata (interface, NULL);
 958                 goto error;
 959         }
 960         dev->minor = interface->minor;
 961
 962         /* let the user know what node this device is now attached to */
 963         info ("LEGO USB Tower #%d now attached to major %d minor %d", (dev->minor - LEGO_USB_TOWER_MINOR_BASE), USB_MAJOR, dev->minor);
 964
 965         /* get the firmware version and log it */
 966         result = usb_control_msg (udev,
 967                                   usb_rcvctrlpipe(udev, 0),
 968                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
 969                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 970                                   0,
 971                                   0,
 972                                   &get_version_reply,
 973                                   sizeof(get_version_reply),
 974                                   1000);
 975         if (result < 0) {
 976                 err("LEGO USB Tower get version control request failed");
 977                 retval = result;
 978                 goto error;
 979         }
 980         info("LEGO USB Tower firmware version is %d.%d build %d",
 981              get_version_reply.major,
 982              get_version_reply.minor,
 983              le16_to_cpu(get_version_reply.build_no));
 984
 985
 986 exit:
 987         dbg(2, "%s: leave, return value 0x%.8lx (dev)", __FUNCTION__, (long) dev);
 988
 989         return retval;
 990
 991 error:
 992         tower_delete(dev);
 993         return retval;
 994 }
 995
 996
 997 /**
 998  *      tower_disconnect
 999  *
1000  *      Called by the usb core when the device is removed from the system.
1001  */
1002 static void tower_disconnect (struct usb_interface *interface)
1003 {
1004         struct lego_usb_tower *dev;
1005         int minor;
1006
1007         dbg(2, "%s: enter", __FUNCTION__);
1008
1009         down (&disconnect_sem);
1010
1011         dev = usb_get_intfdata (interface);
1012         usb_set_intfdata (interface, NULL);
1013
1014
1015         down (&dev->sem);
1016
1017         minor = dev->minor;
1018
1019         /* give back our minor */
1020         usb_deregister_dev (interface, &tower_class);
1021
1022         /* if the device is not opened, then we clean up right now */
1023         if (!dev->open_count) {
1024                 up (&dev->sem);
1025                 tower_delete (dev);
1026         } else {
1027                 dev->udev = NULL;
1028                 up (&dev->sem);
1029         }
1030
1031         up (&disconnect_sem);
1032
1033         info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));
1034
1035         dbg(2, "%s: leave", __FUNCTION__);
1036 }
1037
1038
1039
1040 /**
1041  *      lego_usb_tower_init
1042  */
1043 static int __init lego_usb_tower_init(void)
1044 {
1045         int result;
1046         int retval = 0;
1047
1048         dbg(2, "%s: enter", __FUNCTION__);
1049
1050         /* register this driver with the USB subsystem */
1051         result = usb_register(&tower_driver);
1052         if (result < 0) {
1053                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1054                 retval = -1;
1055                 goto exit;
1056         }
1057
1058         info(DRIVER_DESC " " DRIVER_VERSION);
1059
1060 exit:
1061         dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
1062
1063         return retval;
1064 }
1065
1066
1067 /**
1068  *      lego_usb_tower_exit
1069  */
1070 static void __exit lego_usb_tower_exit(void)
1071 {
1072         dbg(2, "%s: enter", __FUNCTION__);
1073
1074         /* deregister this driver with the USB subsystem */
1075         usb_deregister (&tower_driver);
1076
1077         dbg(2, "%s: leave", __FUNCTION__);
1078 }
1079
1080 module_init (lego_usb_tower_init);
1081 module_exit (lego_usb_tower_exit);
1082
1083 MODULE_AUTHOR(DRIVER_AUTHOR);
1084 MODULE_DESCRIPTION(DRIVER_DESC);
1085 #ifdef MODULE_LICENSE
1086 MODULE_LICENSE("GPL");
1087 #endif