drivers/usb/misc/legousbtower.c

   1 /*
   2  * LEGO USB Tower driver
   3  *
   4  * Copyright (C) 2003 David Glance <davidgsf@sourceforge.net>
   5  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License as
   9  *      published by the Free Software Foundation; either version 2 of
  10  *      the License, or (at your option) any later version.
  11  *
  12  * derived from USB Skeleton driver - 0.5
  13  * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
  14  *
  15  * History:
  16  *
  17  * 2001-10-13 - 0.1 js
  18  *   - first version
  19  * 2001-11-03 - 0.2 js
  20  *   - simplified buffering, one-shot URBs for writing
  21  * 2001-11-10 - 0.3 js
  22  *   - removed IOCTL (setting power/mode is more complicated, postponed)
  23  * 2001-11-28 - 0.4 js
  24  *   - added vendor commands for mode of operation and power level in open
  25  * 2001-12-04 - 0.5 js
  26  *   - set IR mode by default (by oversight 0.4 set VLL mode)
  27  * 2002-01-11 - 0.5? pcchan
  28  *   - make read buffer reusable and work around bytes_to_write issue between
  29  *     uhci and legusbtower
  30  * 2002-09-23 - 0.52 david (david@csse.uwa.edu.au)
  31  *   - imported into lejos project
  32  *   - changed wake_up to wake_up_interruptible
  33  *   - changed to use lego0 rather than tower0
  34  *   - changed dbg() to use __func__ rather than deprecated __func__
  35  * 2003-01-12 - 0.53 david (david@csse.uwa.edu.au)
  36  *   - changed read and write to write everything or
  37  *     timeout (from a patch by Chris Riesen and Brett Thaeler driver)
  38  *   - added ioctl functionality to set timeouts
  39  * 2003-07-18 - 0.54 davidgsf (david@csse.uwa.edu.au)
  40  *   - initial import into LegoUSB project
  41  *   - merge of existing LegoUSB.c driver
  42  * 2003-07-18 - 0.56 davidgsf (david@csse.uwa.edu.au)
  43  *   - port to 2.6 style driver
  44  * 2004-02-29 - 0.6 Juergen Stuber <starblue@users.sourceforge.net>
  45  *   - fix locking
  46  *   - unlink read URBs which are no longer needed
  47  *   - allow increased buffer size, eliminates need for timeout on write
  48  *   - have read URB running continuously
  49  *   - added poll
  50  *   - forbid seeking
  51  *   - added nonblocking I/O
  52  *   - changed back __func__ to __func__
  53  *   - read and log tower firmware version
  54  *   - reset tower on probe, avoids failure of first write
  55  * 2004-03-09 - 0.7 Juergen Stuber <starblue@users.sourceforge.net>
  56  *   - timeout read now only after inactivity, shorten default accordingly
  57  * 2004-03-11 - 0.8 Juergen Stuber <starblue@users.sourceforge.net>
  58  *   - log major, minor instead of possibly confusing device filename
  59  *   - whitespace cleanup
  60  * 2004-03-12 - 0.9 Juergen Stuber <starblue@users.sourceforge.net>
  61  *   - normalize whitespace in debug messages
  62  *   - take care about endianness in control message responses
  63  * 2004-03-13 - 0.91 Juergen Stuber <starblue@users.sourceforge.net>
  64  *   - make default intervals longer to accommodate current EHCI driver
  65  * 2004-03-19 - 0.92 Juergen Stuber <starblue@users.sourceforge.net>
  66  *   - replaced atomic_t by memory barriers
  67  * 2004-04-21 - 0.93 Juergen Stuber <starblue@users.sourceforge.net>
  68  *   - wait for completion of write urb in release (needed for remotecontrol)
  69  *   - corrected poll for write direction (missing negation)
  70  * 2004-04-22 - 0.94 Juergen Stuber <starblue@users.sourceforge.net>
  71  *   - make device locking interruptible
  72  * 2004-04-30 - 0.95 Juergen Stuber <starblue@users.sourceforge.net>
  73  *   - check for valid udev on resubmitting and unlinking urbs
  74  * 2004-08-03 - 0.96 Juergen Stuber <starblue@users.sourceforge.net>
  75  *   - move reset into open to clean out spurious data
  76  */
  77
  78 #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 <linux/smp_lock.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 const 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 static DEFINE_MUTEX(open_disc_mutex);
 203
 204 #define LEGO_USB_TOWER_MINOR_BASE       160
 205
 206
 207 /* Structure to hold all of our device specific stuff */
 208 struct lego_usb_tower {
 209         struct mutex            lock;           /* locks this structure */
 210         struct usb_device*      udev;           /* save off the usb device pointer */
 211         unsigned char           minor;          /* the starting minor number for this device */
 212
 213         int                     open_count;     /* number of times this port has been opened */
 214
 215         char*                   read_buffer;
 216         size_t                  read_buffer_length; /* this much came in */
 217         size_t                  read_packet_length; /* this much will be returned on read */
 218         spinlock_t              read_buffer_lock;
 219         int                     packet_timeout_jiffies;
 220         unsigned long           read_last_arrival;
 221
 222         wait_queue_head_t       read_wait;
 223         wait_queue_head_t       write_wait;
 224
 225         char*                   interrupt_in_buffer;
 226         struct usb_endpoint_descriptor* interrupt_in_endpoint;
 227         struct urb*             interrupt_in_urb;
 228         int                     interrupt_in_interval;
 229         int                     interrupt_in_running;
 230         int                     interrupt_in_done;
 231
 232         char*                   interrupt_out_buffer;
 233         struct usb_endpoint_descriptor* interrupt_out_endpoint;
 234         struct urb*             interrupt_out_urb;
 235         int                     interrupt_out_interval;
 236         int                     interrupt_out_busy;
 237
 238 };
 239
 240
 241 /* local function prototypes */
 242 static ssize_t tower_read       (struct file *file, char __user *buffer, size_t count, loff_t *ppos);
 243 static ssize_t tower_write      (struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
 244 static inline void tower_delete (struct lego_usb_tower *dev);
 245 static int tower_open           (struct inode *inode, struct file *file);
 246 static int tower_release        (struct inode *inode, struct file *file);
 247 static unsigned int tower_poll  (struct file *file, poll_table *wait);
 248 static loff_t tower_llseek      (struct file *file, loff_t off, int whence);
 249
 250 static void tower_abort_transfers (struct lego_usb_tower *dev);
 251 static void tower_check_for_read_packet (struct lego_usb_tower *dev);
 252 static void tower_interrupt_in_callback (struct urb *urb);
 253 static void tower_interrupt_out_callback (struct urb *urb);
 254
 255 static int  tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
 256 static void tower_disconnect    (struct usb_interface *interface);
 257
 258
 259 /* file operations needed when we register this driver */
 260 static const 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 static char *legousbtower_devnode(struct device *dev, mode_t *mode)
 271 {
 272         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
 273 }
 274
 275 /*
 276  * usb class driver info in order to get a minor number from the usb core,
 277  * and to have the device registered with the driver core
 278  */
 279 static struct usb_class_driver tower_class = {
 280         .name =         "legousbtower%d",
 281         .devnode =      legousbtower_devnode,
 282         .fops =         &tower_fops,
 283         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
 284 };
 285
 286
 287 /* usb specific object needed to register this driver with the usb subsystem */
 288 static struct usb_driver tower_driver = {
 289         .name =         "legousbtower",
 290         .probe =        tower_probe,
 291         .disconnect =   tower_disconnect,
 292         .id_table =     tower_table,
 293 };
 294
 295
 296 /**
 297  *      lego_usb_tower_debug_data
 298  */
 299 static inline void lego_usb_tower_debug_data (int level, const char *function, int size, const unsigned char *data)
 300 {
 301         int i;
 302
 303         if (debug < level)
 304                 return;
 305
 306         printk (KERN_DEBUG __FILE__": %s - length = %d, data = ", function, size);
 307         for (i = 0; i < size; ++i) {
 308                 printk ("%.2x ", data[i]);
 309         }
 310         printk ("\n");
 311 }
 312
 313
 314 /**
 315  *      tower_delete
 316  */
 317 static inline void tower_delete (struct lego_usb_tower *dev)
 318 {
 319         dbg(2, "%s: enter", __func__);
 320
 321         tower_abort_transfers (dev);
 322
 323         /* free data structures */
 324         usb_free_urb(dev->interrupt_in_urb);
 325         usb_free_urb(dev->interrupt_out_urb);
 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", __func__);
 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         struct tower_reset_reply reset_reply;
 345         int result;
 346
 347         dbg(2, "%s: enter", __func__);
 348
 349         lock_kernel();
 350         nonseekable_open(inode, file);
 351         subminor = iminor(inode);
 352
 353         interface = usb_find_interface (&tower_driver, subminor);
 354
 355         if (!interface) {
 356                 err ("%s - error, can't find device for minor %d",
 357                      __func__, subminor);
 358                 retval = -ENODEV;
 359                 goto exit;
 360         }
 361
 362         mutex_lock(&open_disc_mutex);
 363         dev = usb_get_intfdata(interface);
 364
 365         if (!dev) {
 366                 mutex_unlock(&open_disc_mutex);
 367                 retval = -ENODEV;
 368                 goto exit;
 369         }
 370
 371         /* lock this device */
 372         if (mutex_lock_interruptible(&dev->lock)) {
 373                 mutex_unlock(&open_disc_mutex);
 374                 retval = -ERESTARTSYS;
 375                 goto exit;
 376         }
 377
 378
 379         /* allow opening only once */
 380         if (dev->open_count) {
 381                 mutex_unlock(&open_disc_mutex);
 382                 retval = -EBUSY;
 383                 goto unlock_exit;
 384         }
 385         dev->open_count = 1;
 386         mutex_unlock(&open_disc_mutex);
 387
 388         /* reset the tower */
 389         result = usb_control_msg (dev->udev,
 390                                   usb_rcvctrlpipe(dev->udev, 0),
 391                                   LEGO_USB_TOWER_REQUEST_RESET,
 392                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 393                                   0,
 394                                   0,
 395                                   &reset_reply,
 396                                   sizeof(reset_reply),
 397                                   1000);
 398         if (result < 0) {
 399                 err("LEGO USB Tower reset control request failed");
 400                 retval = result;
 401                 goto unlock_exit;
 402         }
 403
 404         /* initialize in direction */
 405         dev->read_buffer_length = 0;
 406         dev->read_packet_length = 0;
 407         usb_fill_int_urb (dev->interrupt_in_urb,
 408                           dev->udev,
 409                           usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
 410                           dev->interrupt_in_buffer,
 411                           le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
 412                           tower_interrupt_in_callback,
 413                           dev,
 414                           dev->interrupt_in_interval);
 415
 416         dev->interrupt_in_running = 1;
 417         dev->interrupt_in_done = 0;
 418         mb();
 419
 420         retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
 421         if (retval) {
 422                 err("Couldn't submit interrupt_in_urb %d", retval);
 423                 dev->interrupt_in_running = 0;
 424                 dev->open_count = 0;
 425                 goto unlock_exit;
 426         }
 427
 428         /* save device in the file's private structure */
 429         file->private_data = dev;
 430
 431 unlock_exit:
 432         mutex_unlock(&dev->lock);
 433
 434 exit:
 435         unlock_kernel();
 436         dbg(2, "%s: leave, return value %d ", __func__, retval);
 437
 438         return retval;
 439 }
 440
 441 /**
 442  *      tower_release
 443  */
 444 static int tower_release (struct inode *inode, struct file *file)
 445 {
 446         struct lego_usb_tower *dev;
 447         int retval = 0;
 448
 449         dbg(2, "%s: enter", __func__);
 450
 451         dev = (struct lego_usb_tower *)file->private_data;
 452
 453         if (dev == NULL) {
 454                 dbg(1, "%s: object is NULL", __func__);
 455                 retval = -ENODEV;
 456                 goto exit_nolock;
 457         }
 458
 459         mutex_lock(&open_disc_mutex);
 460         if (mutex_lock_interruptible(&dev->lock)) {
 461                 retval = -ERESTARTSYS;
 462                 goto exit;
 463         }
 464
 465         if (dev->open_count != 1) {
 466                 dbg(1, "%s: device not opened exactly once", __func__);
 467                 retval = -ENODEV;
 468                 goto unlock_exit;
 469         }
 470         if (dev->udev == NULL) {
 471                 /* the device was unplugged before the file was released */
 472
 473                 /* unlock here as tower_delete frees dev */
 474                 mutex_unlock(&dev->lock);
 475                 tower_delete (dev);
 476                 goto exit;
 477         }
 478
 479         /* wait until write transfer is finished */
 480         if (dev->interrupt_out_busy) {
 481                 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
 482         }
 483         tower_abort_transfers (dev);
 484         dev->open_count = 0;
 485
 486 unlock_exit:
 487         mutex_unlock(&dev->lock);
 488
 489 exit:
 490         mutex_unlock(&open_disc_mutex);
 491 exit_nolock:
 492         dbg(2, "%s: leave, return value %d", __func__, retval);
 493         return retval;
 494 }
 495
 496
 497 /**
 498  *      tower_abort_transfers
 499  *      aborts transfers and frees associated data structures
 500  */
 501 static void tower_abort_transfers (struct lego_usb_tower *dev)
 502 {
 503         dbg(2, "%s: enter", __func__);
 504
 505         if (dev == NULL) {
 506                 dbg(1, "%s: dev is null", __func__);
 507                 goto exit;
 508         }
 509
 510         /* shutdown transfer */
 511         if (dev->interrupt_in_running) {
 512                 dev->interrupt_in_running = 0;
 513                 mb();
 514                 if (dev->udev)
 515                         usb_kill_urb (dev->interrupt_in_urb);
 516         }
 517         if (dev->interrupt_out_busy && dev->udev)
 518                 usb_kill_urb(dev->interrupt_out_urb);
 519
 520 exit:
 521         dbg(2, "%s: leave", __func__);
 522 }
 523
 524
 525 /**
 526  *      tower_check_for_read_packet
 527  *
 528  *      To get correct semantics for signals and non-blocking I/O
 529  *      with packetizing we pretend not to see any data in the read buffer
 530  *      until it has been there unchanged for at least
 531  *      dev->packet_timeout_jiffies, or until the buffer is full.
 532  */
 533 static void tower_check_for_read_packet (struct lego_usb_tower *dev)
 534 {
 535         spin_lock_irq (&dev->read_buffer_lock);
 536         if (!packet_timeout
 537             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
 538             || dev->read_buffer_length == read_buffer_size) {
 539                 dev->read_packet_length = dev->read_buffer_length;
 540         }
 541         dev->interrupt_in_done = 0;
 542         spin_unlock_irq (&dev->read_buffer_lock);
 543 }
 544
 545
 546 /**
 547  *      tower_poll
 548  */
 549 static unsigned int tower_poll (struct file *file, poll_table *wait)
 550 {
 551         struct lego_usb_tower *dev;
 552         unsigned int mask = 0;
 553
 554         dbg(2, "%s: enter", __func__);
 555
 556         dev = file->private_data;
 557
 558         if (!dev->udev)
 559                 return POLLERR | POLLHUP;
 560
 561         poll_wait(file, &dev->read_wait, wait);
 562         poll_wait(file, &dev->write_wait, wait);
 563
 564         tower_check_for_read_packet(dev);
 565         if (dev->read_packet_length > 0) {
 566                 mask |= POLLIN | POLLRDNORM;
 567         }
 568         if (!dev->interrupt_out_busy) {
 569                 mask |= POLLOUT | POLLWRNORM;
 570         }
 571
 572         dbg(2, "%s: leave, mask = %d", __func__, mask);
 573
 574         return mask;
 575 }
 576
 577
 578 /**
 579  *      tower_llseek
 580  */
 581 static loff_t tower_llseek (struct file *file, loff_t off, int whence)
 582 {
 583         return -ESPIPE;         /* unseekable */
 584 }
 585
 586
 587 /**
 588  *      tower_read
 589  */
 590 static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 591 {
 592         struct lego_usb_tower *dev;
 593         size_t bytes_to_read;
 594         int i;
 595         int retval = 0;
 596         unsigned long timeout = 0;
 597
 598         dbg(2, "%s: enter, count = %Zd", __func__, count);
 599
 600         dev = (struct lego_usb_tower *)file->private_data;
 601
 602         /* lock this object */
 603         if (mutex_lock_interruptible(&dev->lock)) {
 604                 retval = -ERESTARTSYS;
 605                 goto exit;
 606         }
 607
 608         /* verify that the device wasn't unplugged */
 609         if (dev->udev == NULL) {
 610                 retval = -ENODEV;
 611                 err("No device or device unplugged %d", retval);
 612                 goto unlock_exit;
 613         }
 614
 615         /* verify that we actually have some data to read */
 616         if (count == 0) {
 617                 dbg(1, "%s: read request of 0 bytes", __func__);
 618                 goto unlock_exit;
 619         }
 620
 621         if (read_timeout) {
 622                 timeout = jiffies + read_timeout * HZ / 1000;
 623         }
 624
 625         /* wait for data */
 626         tower_check_for_read_packet (dev);
 627         while (dev->read_packet_length == 0) {
 628                 if (file->f_flags & O_NONBLOCK) {
 629                         retval = -EAGAIN;
 630                         goto unlock_exit;
 631                 }
 632                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
 633                 if (retval < 0) {
 634                         goto unlock_exit;
 635                 }
 636
 637                 /* reset read timeout during read or write activity */
 638                 if (read_timeout
 639                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
 640                         timeout = jiffies + read_timeout * HZ / 1000;
 641                 }
 642                 /* check for read timeout */
 643                 if (read_timeout && time_after (jiffies, timeout)) {
 644                         retval = -ETIMEDOUT;
 645                         goto unlock_exit;
 646                 }
 647                 tower_check_for_read_packet (dev);
 648         }
 649
 650         /* copy the data from read_buffer into userspace */
 651         bytes_to_read = min(count, dev->read_packet_length);
 652
 653         if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
 654                 retval = -EFAULT;
 655                 goto unlock_exit;
 656         }
 657
 658         spin_lock_irq (&dev->read_buffer_lock);
 659         dev->read_buffer_length -= bytes_to_read;
 660         dev->read_packet_length -= bytes_to_read;
 661         for (i=0; i<dev->read_buffer_length; i++) {
 662                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
 663         }
 664         spin_unlock_irq (&dev->read_buffer_lock);
 665
 666         retval = bytes_to_read;
 667
 668 unlock_exit:
 669         /* unlock the device */
 670         mutex_unlock(&dev->lock);
 671
 672 exit:
 673         dbg(2, "%s: leave, return value %d", __func__, retval);
 674         return retval;
 675 }
 676
 677
 678 /**
 679  *      tower_write
 680  */
 681 static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 682 {
 683         struct lego_usb_tower *dev;
 684         size_t bytes_to_write;
 685         int retval = 0;
 686
 687         dbg(2, "%s: enter, count = %Zd", __func__, count);
 688
 689         dev = (struct lego_usb_tower *)file->private_data;
 690
 691         /* lock this object */
 692         if (mutex_lock_interruptible(&dev->lock)) {
 693                 retval = -ERESTARTSYS;
 694                 goto exit;
 695         }
 696
 697         /* verify that the device wasn't unplugged */
 698         if (dev->udev == NULL) {
 699                 retval = -ENODEV;
 700                 err("No device or device unplugged %d", retval);
 701                 goto unlock_exit;
 702         }
 703
 704         /* verify that we actually have some data to write */
 705         if (count == 0) {
 706                 dbg(1, "%s: write request of 0 bytes", __func__);
 707                 goto unlock_exit;
 708         }
 709
 710         /* wait until previous transfer is finished */
 711         while (dev->interrupt_out_busy) {
 712                 if (file->f_flags & O_NONBLOCK) {
 713                         retval = -EAGAIN;
 714                         goto unlock_exit;
 715                 }
 716                 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
 717                 if (retval) {
 718                         goto unlock_exit;
 719                 }
 720         }
 721
 722         /* write the data into interrupt_out_buffer from userspace */
 723         bytes_to_write = min_t(int, count, write_buffer_size);
 724         dbg(4, "%s: count = %Zd, bytes_to_write = %Zd", __func__, count, bytes_to_write);
 725
 726         if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 727                 retval = -EFAULT;
 728                 goto unlock_exit;
 729         }
 730
 731         /* send off the urb */
 732         usb_fill_int_urb(dev->interrupt_out_urb,
 733                          dev->udev,
 734                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 735                          dev->interrupt_out_buffer,
 736                          bytes_to_write,
 737                          tower_interrupt_out_callback,
 738                          dev,
 739                          dev->interrupt_out_interval);
 740
 741         dev->interrupt_out_busy = 1;
 742         wmb();
 743
 744         retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
 745         if (retval) {
 746                 dev->interrupt_out_busy = 0;
 747                 err("Couldn't submit interrupt_out_urb %d", retval);
 748                 goto unlock_exit;
 749         }
 750         retval = bytes_to_write;
 751
 752 unlock_exit:
 753         /* unlock the device */
 754         mutex_unlock(&dev->lock);
 755
 756 exit:
 757         dbg(2, "%s: leave, return value %d", __func__, retval);
 758
 759         return retval;
 760 }
 761
 762
 763 /**
 764  *      tower_interrupt_in_callback
 765  */
 766 static void tower_interrupt_in_callback (struct urb *urb)
 767 {
 768         struct lego_usb_tower *dev = urb->context;
 769         int status = urb->status;
 770         int retval;
 771
 772         dbg(4, "%s: enter, status %d", __func__, status);
 773
 774         lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
 775
 776         if (status) {
 777                 if (status == -ENOENT ||
 778                     status == -ECONNRESET ||
 779                     status == -ESHUTDOWN) {
 780                         goto exit;
 781                 } else {
 782                         dbg(1, "%s: nonzero status received: %d", __func__, status);
 783                         goto resubmit; /* maybe we can recover */
 784                 }
 785         }
 786
 787         if (urb->actual_length > 0) {
 788                 spin_lock (&dev->read_buffer_lock);
 789                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
 790                         memcpy (dev->read_buffer + dev->read_buffer_length,
 791                                 dev->interrupt_in_buffer,
 792                                 urb->actual_length);
 793                         dev->read_buffer_length += urb->actual_length;
 794                         dev->read_last_arrival = jiffies;
 795                         dbg(3, "%s: received %d bytes", __func__, urb->actual_length);
 796                 } else {
 797                         printk(KERN_WARNING "%s: read_buffer overflow, %d bytes dropped", __func__, urb->actual_length);
 798                 }
 799                 spin_unlock (&dev->read_buffer_lock);
 800         }
 801
 802 resubmit:
 803         /* resubmit if we're still running */
 804         if (dev->interrupt_in_running && dev->udev) {
 805                 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
 806                 if (retval) {
 807                         err("%s: usb_submit_urb failed (%d)", __func__, retval);
 808                 }
 809         }
 810
 811 exit:
 812         dev->interrupt_in_done = 1;
 813         wake_up_interruptible (&dev->read_wait);
 814
 815         lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
 816         dbg(4, "%s: leave, status %d", __func__, status);
 817 }
 818
 819
 820 /**
 821  *      tower_interrupt_out_callback
 822  */
 823 static void tower_interrupt_out_callback (struct urb *urb)
 824 {
 825         struct lego_usb_tower *dev = urb->context;
 826         int status = urb->status;
 827
 828         dbg(4, "%s: enter, status %d", __func__, status);
 829         lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
 830
 831         /* sync/async unlink faults aren't errors */
 832         if (status && !(status == -ENOENT ||
 833                         status == -ECONNRESET ||
 834                         status == -ESHUTDOWN)) {
 835                 dbg(1, "%s - nonzero write bulk status received: %d",
 836                     __func__, status);
 837         }
 838
 839         dev->interrupt_out_busy = 0;
 840         wake_up_interruptible(&dev->write_wait);
 841
 842         lego_usb_tower_debug_data(5, __func__, urb->actual_length, urb->transfer_buffer);
 843         dbg(4, "%s: leave, status %d", __func__, status);
 844 }
 845
 846
 847 /**
 848  *      tower_probe
 849  *
 850  *      Called by the usb core when a new device is connected that it thinks
 851  *      this driver might be interested in.
 852  */
 853 static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
 854 {
 855         struct usb_device *udev = interface_to_usbdev(interface);
 856         struct lego_usb_tower *dev = NULL;
 857         struct usb_host_interface *iface_desc;
 858         struct usb_endpoint_descriptor* endpoint;
 859         struct tower_get_version_reply get_version_reply;
 860         int i;
 861         int retval = -ENOMEM;
 862         int result;
 863
 864         dbg(2, "%s: enter", __func__);
 865
 866         if (udev == NULL)
 867                 dev_info(&interface->dev, "udev is NULL.\n");
 868
 869         /* allocate memory for our device state and initialize it */
 870
 871         dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
 872
 873         if (dev == NULL) {
 874                 err ("Out of memory");
 875                 goto exit;
 876         }
 877
 878         mutex_init(&dev->lock);
 879
 880         dev->udev = udev;
 881         dev->open_count = 0;
 882
 883         dev->read_buffer = NULL;
 884         dev->read_buffer_length = 0;
 885         dev->read_packet_length = 0;
 886         spin_lock_init (&dev->read_buffer_lock);
 887         dev->packet_timeout_jiffies = packet_timeout * HZ / 1000;
 888         dev->read_last_arrival = jiffies;
 889
 890         init_waitqueue_head (&dev->read_wait);
 891         init_waitqueue_head (&dev->write_wait);
 892
 893         dev->interrupt_in_buffer = NULL;
 894         dev->interrupt_in_endpoint = NULL;
 895         dev->interrupt_in_urb = NULL;
 896         dev->interrupt_in_running = 0;
 897         dev->interrupt_in_done = 0;
 898
 899         dev->interrupt_out_buffer = NULL;
 900         dev->interrupt_out_endpoint = NULL;
 901         dev->interrupt_out_urb = NULL;
 902         dev->interrupt_out_busy = 0;
 903
 904         iface_desc = interface->cur_altsetting;
 905
 906         /* set up the endpoint information */
 907         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 908                 endpoint = &iface_desc->endpoint[i].desc;
 909
 910                 if (usb_endpoint_xfer_int(endpoint)) {
 911                         if (usb_endpoint_dir_in(endpoint))
 912                                 dev->interrupt_in_endpoint = endpoint;
 913                         else
 914                                 dev->interrupt_out_endpoint = endpoint;
 915                 }
 916         }
 917         if(dev->interrupt_in_endpoint == NULL) {
 918                 err("interrupt in endpoint not found");
 919                 goto error;
 920         }
 921         if (dev->interrupt_out_endpoint == NULL) {
 922                 err("interrupt out endpoint not found");
 923                 goto error;
 924         }
 925
 926         dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
 927         if (!dev->read_buffer) {
 928                 err("Couldn't allocate read_buffer");
 929                 goto error;
 930         }
 931         dev->interrupt_in_buffer = kmalloc (le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize), GFP_KERNEL);
 932         if (!dev->interrupt_in_buffer) {
 933                 err("Couldn't allocate interrupt_in_buffer");
 934                 goto error;
 935         }
 936         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 937         if (!dev->interrupt_in_urb) {
 938                 err("Couldn't allocate interrupt_in_urb");
 939                 goto error;
 940         }
 941         dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
 942         if (!dev->interrupt_out_buffer) {
 943                 err("Couldn't allocate interrupt_out_buffer");
 944                 goto error;
 945         }
 946         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 947         if (!dev->interrupt_out_urb) {
 948                 err("Couldn't allocate interrupt_out_urb");
 949                 goto error;
 950         }
 951         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 952         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 953
 954         /* we can register the device now, as it is ready */
 955         usb_set_intfdata (interface, dev);
 956
 957         retval = usb_register_dev (interface, &tower_class);
 958
 959         if (retval) {
 960                 /* something prevented us from registering this driver */
 961                 err ("Not able to get a minor for this device.");
 962                 usb_set_intfdata (interface, NULL);
 963                 goto error;
 964         }
 965         dev->minor = interface->minor;
 966
 967         /* let the user know what node this device is now attached to */
 968         dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
 969                  "%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
 970                  USB_MAJOR, dev->minor);
 971
 972         /* get the firmware version and log it */
 973         result = usb_control_msg (udev,
 974                                   usb_rcvctrlpipe(udev, 0),
 975                                   LEGO_USB_TOWER_REQUEST_GET_VERSION,
 976                                   USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 977                                   0,
 978                                   0,
 979                                   &get_version_reply,
 980                                   sizeof(get_version_reply),
 981                                   1000);
 982         if (result < 0) {
 983                 err("LEGO USB Tower get version control request failed");
 984                 retval = result;
 985                 goto error;
 986         }
 987         dev_info(&interface->dev, "LEGO USB Tower firmware version is %d.%d "
 988                  "build %d\n", get_version_reply.major,
 989                  get_version_reply.minor,
 990                  le16_to_cpu(get_version_reply.build_no));
 991
 992
 993 exit:
 994         dbg(2, "%s: leave, return value 0x%.8lx (dev)", __func__, (long) dev);
 995
 996         return retval;
 997
 998 error:
 999         tower_delete(dev);
1000         return retval;
1001 }
1002
1003
1004 /**
1005  *      tower_disconnect
1006  *
1007  *      Called by the usb core when the device is removed from the system.
1008  */
1009 static void tower_disconnect (struct usb_interface *interface)
1010 {
1011         struct lego_usb_tower *dev;
1012         int minor;
1013
1014         dbg(2, "%s: enter", __func__);
1015
1016         dev = usb_get_intfdata (interface);
1017         mutex_lock(&open_disc_mutex);
1018         usb_set_intfdata (interface, NULL);
1019
1020         minor = dev->minor;
1021
1022         /* give back our minor */
1023         usb_deregister_dev (interface, &tower_class);
1024
1025         mutex_lock(&dev->lock);
1026         mutex_unlock(&open_disc_mutex);
1027
1028         /* if the device is not opened, then we clean up right now */
1029         if (!dev->open_count) {
1030                 mutex_unlock(&dev->lock);
1031                 tower_delete (dev);
1032         } else {
1033                 dev->udev = NULL;
1034                 /* wake up pollers */
1035                 wake_up_interruptible_all(&dev->read_wait);
1036                 wake_up_interruptible_all(&dev->write_wait);
1037                 mutex_unlock(&dev->lock);
1038         }
1039
1040         dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
1041                  (minor - LEGO_USB_TOWER_MINOR_BASE));
1042
1043         dbg(2, "%s: leave", __func__);
1044 }
1045
1046
1047
1048 /**
1049  *      lego_usb_tower_init
1050  */
1051 static int __init lego_usb_tower_init(void)
1052 {
1053         int result;
1054         int retval = 0;
1055
1056         dbg(2, "%s: enter", __func__);
1057
1058         /* register this driver with the USB subsystem */
1059         result = usb_register(&tower_driver);
1060         if (result < 0) {
1061                 err("usb_register failed for the "__FILE__" driver. Error number %d", result);
1062                 retval = -1;
1063                 goto exit;
1064         }
1065
1066         printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
1067                DRIVER_DESC "\n");
1068
1069 exit:
1070         dbg(2, "%s: leave, return value %d", __func__, retval);
1071
1072         return retval;
1073 }
1074
1075
1076 /**
1077  *      lego_usb_tower_exit
1078  */
1079 static void __exit lego_usb_tower_exit(void)
1080 {
1081         dbg(2, "%s: enter", __func__);
1082
1083         /* deregister this driver with the USB subsystem */
1084         usb_deregister (&tower_driver);
1085
1086         dbg(2, "%s: leave", __func__);
1087 }
1088
1089 module_init (lego_usb_tower_init);
1090 module_exit (lego_usb_tower_exit);
1091
1092 MODULE_AUTHOR(DRIVER_AUTHOR);
1093 MODULE_DESCRIPTION(DRIVER_DESC);
1094 #ifdef MODULE_LICENSE
1095 MODULE_LICENSE("GPL");
1096 #endif