drivers/usb/misc/legousbtower.c

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