drivers/staging/frontier/alphatrack.c

   1 /*
   2  * Frontier Designs Alphatrack driver
   3  *
   4  * Copyright (C) 2007 Michael Taht (m@taht.net)
   5  *
   6  * Based on the usbled driver and ldusb drivers by
   7  *
   8  * Copyright (C) 2004 Greg Kroah-Hartman (greg@kroah.com)
   9  * Copyright (C) 2005 Michael Hund <mhund@ld-didactic.de>
  10  *
  11  * The ldusb driver was, in turn, derived from Lego USB Tower driver
  12  * Copyright (C) 2003 David Glance <advidgsf@sourceforge.net>
  13  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
  14  *
  15  *      This program is free software; you can redistribute it and/or
  16  *      modify it under the terms of the GNU General Public License as
  17  *      published by the Free Software Foundation, version 2.
  18  *
  19  */
  20
  21 /**
  22  * This driver uses a ring buffer for time critical reading of
  23  * interrupt in reports and provides read and write methods for
  24  * raw interrupt reports.
  25  */
  26
  27 /* Note: this currently uses a dumb ringbuffer for reads and writes.
  28  * A more optimal driver would cache and kill off outstanding urbs that are
  29  * now invalid, and ignore ones that already were in the queue but valid
  30  * as we only have 30 commands for the alphatrack. In particular this is
  31  * key for getting lights to flash in time as otherwise many commands
  32  * can be buffered up before the light change makes it to the interface.
  33 */
  34
  35 #include <linux/kernel.h>
  36 #include <linux/errno.h>
  37 #include <linux/init.h>
  38 #include <linux/slab.h>
  39 #include <linux/module.h>
  40 #include <linux/kobject.h>
  41 #include <linux/mutex.h>
  42 #include <linux/version.h>
  43
  44 #include <linux/uaccess.h>
  45 #include <linux/input.h>
  46 #include <linux/usb.h>
  47 #include <linux/poll.h>
  48
  49 #include "alphatrack.h"
  50
  51 #define VENDOR_ID       0x165b
  52 #define PRODUCT_ID      0xfad1
  53
  54 #ifdef CONFIG_USB_DYNAMIC_MINORS
  55 #define USB_ALPHATRACK_MINOR_BASE       0
  56 #else
  57 /* FIXME 176 - is another driver's minor - apply for that */
  58 #define USB_ALPHATRACK_MINOR_BASE       176
  59 #endif
  60
  61 /* table of devices that work with this driver */
  62 static struct usb_device_id usb_alphatrack_table[] = {
  63         {USB_DEVICE(VENDOR_ID, PRODUCT_ID)},
  64         {}                      /* Terminating entry */
  65 };
  66
  67 MODULE_DEVICE_TABLE(usb, usb_alphatrack_table);
  68 MODULE_VERSION("0.41");
  69 MODULE_AUTHOR("Mike Taht <m@taht.net>");
  70 MODULE_DESCRIPTION("Alphatrack USB Driver");
  71 MODULE_LICENSE("GPL");
  72 MODULE_SUPPORTED_DEVICE("Frontier Designs Alphatrack Control Surface");
  73
  74 /* These aren't done yet */
  75
  76 #define SUPPRESS_EXTRA_ONLINE_EVENTS 0
  77 #define BUFFERED_WRITES 0
  78 #define SUPPRESS_EXTRA_OFFLINE_EVENTS 0
  79 #define COMPRESS_FADER_EVENTS 0
  80
  81 #define BUFFERED_READS 1
  82 #define RING_BUFFER_SIZE 512
  83 #define WRITE_BUFFER_SIZE 34
  84 #define ALPHATRACK_USB_TIMEOUT 10
  85 #define OUTPUT_CMD_SIZE 8
  86 #define INPUT_CMD_SIZE 12
  87 #define ALPHATRACK_DEBUG 0
  88
  89 static int debug = ALPHATRACK_DEBUG;
  90
  91 /* Use our own dbg macro */
  92 #define dbg_info(dev, format, arg...) do \
  93     { if (debug) dev_info(dev , format , ## arg); } while (0)
  94
  95 #define alphatrack_ocmd_info(dev, cmd, format, arg...)
  96
  97 #define alphatrack_icmd_info(dev, cmd, format, arg...)
  98
  99 /* Module parameters */
 100
 101 module_param(debug, int, S_IRUGO | S_IWUSR);
 102 MODULE_PARM_DESC(debug, "Debug enabled or not");
 103
 104 /* All interrupt in transfers are collected in a ring buffer to
 105  * avoid racing conditions and get better performance of the driver.
 106  */
 107
 108 static int ring_buffer_size = RING_BUFFER_SIZE;
 109
 110 module_param(ring_buffer_size, int, S_IRUGO);
 111 MODULE_PARM_DESC(ring_buffer_size, "Read ring buffer size");
 112
 113 /* The write_buffer can one day contain more than one interrupt out transfer.
 114  */
 115
 116 static int write_buffer_size = WRITE_BUFFER_SIZE;
 117 module_param(write_buffer_size, int, S_IRUGO);
 118 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 119
 120 /*
 121  * Increase the interval for debugging purposes.
 122  * or set to 1 to use the standard interval from the endpoint descriptors.
 123  */
 124
 125 static int min_interrupt_in_interval = ALPHATRACK_USB_TIMEOUT;
 126 module_param(min_interrupt_in_interval, int, 0);
 127 MODULE_PARM_DESC(min_interrupt_in_interval,
 128                  "Minimum interrupt in interval in ms");
 129
 130 static int min_interrupt_out_interval = ALPHATRACK_USB_TIMEOUT;
 131 module_param(min_interrupt_out_interval, int, 0);
 132 MODULE_PARM_DESC(min_interrupt_out_interval,
 133                  "Minimum interrupt out interval in ms");
 134
 135 /* Structure to hold all of our device specific stuff */
 136
 137 struct usb_alphatrack {
 138         struct semaphore sem;   /* locks this structure */
 139         struct usb_interface *intf;     /* save off the usb interface pointer */
 140         int open_count;         /* number of times this port has been opened */
 141
 142         /* make gcc happy */
 143         struct alphatrack_icmd (*ring_buffer)[RING_BUFFER_SIZE];
 144         struct alphatrack_ocmd (*write_buffer)[WRITE_BUFFER_SIZE];
 145         unsigned int ring_head;
 146         unsigned int ring_tail;
 147
 148         wait_queue_head_t read_wait;
 149         wait_queue_head_t write_wait;
 150
 151         unsigned char *interrupt_in_buffer;
 152         unsigned char *oldi_buffer;
 153         struct usb_endpoint_descriptor *interrupt_in_endpoint;
 154         struct urb *interrupt_in_urb;
 155         int interrupt_in_interval;
 156         size_t interrupt_in_endpoint_size;
 157         int interrupt_in_running;
 158         int interrupt_in_done;
 159
 160         char *interrupt_out_buffer;
 161         struct usb_endpoint_descriptor *interrupt_out_endpoint;
 162         struct urb *interrupt_out_urb;
 163         int interrupt_out_interval;
 164         size_t interrupt_out_endpoint_size;
 165         int interrupt_out_busy;
 166
 167         atomic_t writes_pending;
 168         int event;              /* alternate interface to events */
 169         int fader;              /* 10 bits */
 170         int lights;             /* 23 bits */
 171         unsigned char dump_state;       /* 0 if disabled 1 if enabled */
 172         unsigned char enable;   /* 0 if disabled 1 if enabled */
 173         unsigned char offline;  /* if the device is out of range or asleep */
 174         unsigned char verbose;  /* be verbose in error reporting */
 175         unsigned char last_cmd[OUTPUT_CMD_SIZE];
 176         unsigned char screen[32];
 177 };
 178
 179 /* prevent races between open() and disconnect() */
 180 static DEFINE_MUTEX(disconnect_mutex);
 181
 182 /* forward declaration */
 183
 184 static struct usb_driver usb_alphatrack_driver;
 185
 186 /**
 187  *      usb_alphatrack_abort_transfers
 188  *      aborts transfers and frees associated data structures
 189  */
 190 static void usb_alphatrack_abort_transfers(struct usb_alphatrack *dev)
 191 {
 192         /* shutdown transfer */
 193         if (dev->interrupt_in_running) {
 194                 dev->interrupt_in_running = 0;
 195                 if (dev->intf)
 196                         usb_kill_urb(dev->interrupt_in_urb);
 197         }
 198         if (dev->interrupt_out_busy)
 199                 if (dev->intf)
 200                         usb_kill_urb(dev->interrupt_out_urb);
 201 }
 202
 203 /**
 204  *      usb_alphatrack_delete
 205  */
 206 static void usb_alphatrack_delete(struct usb_alphatrack *dev)
 207 {
 208         usb_alphatrack_abort_transfers(dev);
 209         usb_free_urb(dev->interrupt_in_urb);
 210         usb_free_urb(dev->interrupt_out_urb);
 211         kfree(dev->ring_buffer);
 212         kfree(dev->interrupt_in_buffer);
 213         kfree(dev->interrupt_out_buffer);
 214         kfree(dev);             /* fixme oldi_buffer */
 215 }
 216
 217 /**
 218  *      usb_alphatrack_interrupt_in_callback
 219  */
 220
 221 static void usb_alphatrack_interrupt_in_callback(struct urb *urb)
 222 {
 223         struct usb_alphatrack *dev = urb->context;
 224         unsigned int next_ring_head;
 225         int retval = -1;
 226
 227         if (urb->status) {
 228                 if (urb->status == -ENOENT ||
 229                     urb->status == -ECONNRESET || urb->status == -ESHUTDOWN) {
 230                         goto exit;
 231                 } else {
 232                         dbg_info(&dev->intf->dev,
 233                                  "%s: nonzero status received: %d\n", __func__,
 234                                  urb->status);
 235                         goto resubmit;  /* maybe we can recover */
 236                 }
 237         }
 238
 239         if (urb->actual_length != INPUT_CMD_SIZE) {
 240                 dev_warn(&dev->intf->dev,
 241                          "Urb length was %d bytes!!"
 242                          "Do something intelligent \n", urb->actual_length);
 243         } else {
 244                 alphatrack_ocmd_info(&dev->intf->dev,
 245                                      &(*dev->ring_buffer)[dev->ring_tail].cmd,
 246                                      "%s", "bla");
 247                 if (memcmp
 248                     (dev->interrupt_in_buffer, dev->oldi_buffer,
 249                      INPUT_CMD_SIZE) == 0) {
 250                         goto resubmit;
 251                 }
 252                 memcpy(dev->oldi_buffer, dev->interrupt_in_buffer,
 253                        INPUT_CMD_SIZE);
 254
 255 #if SUPPRESS_EXTRA_OFFLINE_EVENTS
 256                 if (dev->offline == 2 && dev->interrupt_in_buffer[1] == 0xff)
 257                         goto resubmit;
 258                 if (dev->offline == 1 && dev->interrupt_in_buffer[1] == 0xff) {
 259                         dev->offline = 2;
 260                         goto resubmit;
 261                 }
 262 /* Always pass one offline event up the stack */
 263                 if (dev->offline > 0 && dev->interrupt_in_buffer[1] != 0xff)
 264                         dev->offline = 0;
 265                 if (dev->offline == 0 && dev->interrupt_in_buffer[1] == 0xff)
 266                         dev->offline = 1;
 267 #endif
 268                 dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n",
 269                          __func__, dev->ring_head, dev->ring_tail);
 270                 next_ring_head = (dev->ring_head + 1) % ring_buffer_size;
 271
 272                 if (next_ring_head != dev->ring_tail) {
 273                         memcpy(&((*dev->ring_buffer)[dev->ring_head]),
 274                                dev->interrupt_in_buffer, urb->actual_length);
 275                         dev->ring_head = next_ring_head;
 276                         retval = 0;
 277                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 278                 } else {
 279                         dev_warn(&dev->intf->dev,
 280                                  "Ring buffer overflow, %d bytes dropped\n",
 281                                  urb->actual_length);
 282                         memset(dev->interrupt_in_buffer, 0, urb->actual_length);
 283                 }
 284         }
 285
 286 resubmit:
 287         /* resubmit if we're still running */
 288         if (dev->interrupt_in_running && dev->intf) {
 289                 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 290                 if (retval)
 291                         dev_err(&dev->intf->dev,
 292                                 "usb_submit_urb failed (%d)\n", retval);
 293         }
 294
 295 exit:
 296         dev->interrupt_in_done = 1;
 297         wake_up_interruptible(&dev->read_wait);
 298 }
 299
 300 /**
 301  *      usb_alphatrack_interrupt_out_callback
 302  */
 303 static void usb_alphatrack_interrupt_out_callback(struct urb *urb)
 304 {
 305         struct usb_alphatrack *dev = urb->context;
 306
 307         /* sync/async unlink faults aren't errors */
 308         if (urb->status && !(urb->status == -ENOENT ||
 309                              urb->status == -ECONNRESET ||
 310                              urb->status == -ESHUTDOWN))
 311                 dbg_info(&dev->intf->dev,
 312                          "%s - nonzero write interrupt status received: %d\n",
 313                          __func__, urb->status);
 314         atomic_dec(&dev->writes_pending);
 315         dev->interrupt_out_busy = 0;
 316         wake_up_interruptible(&dev->write_wait);
 317 }
 318
 319 /**
 320  *      usb_alphatrack_open
 321  */
 322 static int usb_alphatrack_open(struct inode *inode, struct file *file)
 323 {
 324         struct usb_alphatrack *dev;
 325         int subminor;
 326         int retval = 0;
 327         struct usb_interface *interface;
 328
 329         nonseekable_open(inode, file);
 330         subminor = iminor(inode);
 331
 332         mutex_lock(&disconnect_mutex);
 333
 334         interface = usb_find_interface(&usb_alphatrack_driver, subminor);
 335
 336         if (!interface) {
 337                 err("%s - error, can't find device for minor %d\n",
 338                     __func__, subminor);
 339                 retval = -ENODEV;
 340                 goto unlock_disconnect_exit;
 341         }
 342
 343         dev = usb_get_intfdata(interface);
 344
 345         if (!dev) {
 346                 retval = -ENODEV;
 347                 goto unlock_disconnect_exit;
 348         }
 349
 350         /* lock this device */
 351         if (down_interruptible(&dev->sem)) {
 352                 retval = -ERESTARTSYS;
 353                 goto unlock_disconnect_exit;
 354         }
 355
 356         /* allow opening only once */
 357         if (dev->open_count) {
 358                 retval = -EBUSY;
 359                 goto unlock_exit;
 360         }
 361         dev->open_count = 1;
 362
 363         /* initialize in direction */
 364         dev->ring_head = 0;
 365         dev->ring_tail = 0;
 366         usb_fill_int_urb(dev->interrupt_in_urb,
 367                          interface_to_usbdev(interface),
 368                          usb_rcvintpipe(interface_to_usbdev(interface),
 369                                         dev->interrupt_in_endpoint->
 370                                         bEndpointAddress),
 371                          dev->interrupt_in_buffer,
 372                          dev->interrupt_in_endpoint_size,
 373                          usb_alphatrack_interrupt_in_callback, dev,
 374                          dev->interrupt_in_interval);
 375
 376         dev->interrupt_in_running = 1;
 377         dev->interrupt_in_done = 0;
 378         dev->enable = 1;
 379         dev->offline = 0;
 380
 381         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 382         if (retval) {
 383                 dev_err(&interface->dev,
 384                         "Couldn't submit interrupt_in_urb %d\n", retval);
 385                 dev->interrupt_in_running = 0;
 386                 dev->open_count = 0;
 387                 goto unlock_exit;
 388         }
 389
 390         /* save device in the file's private structure */
 391         file->private_data = dev;
 392
 393 unlock_exit:
 394         up(&dev->sem);
 395
 396 unlock_disconnect_exit:
 397         mutex_unlock(&disconnect_mutex);
 398
 399         return retval;
 400 }
 401
 402 /**
 403  *      usb_alphatrack_release
 404  */
 405 static int usb_alphatrack_release(struct inode *inode, struct file *file)
 406 {
 407         struct usb_alphatrack *dev;
 408         int retval = 0;
 409
 410         dev = file->private_data;
 411
 412         if (dev == NULL) {
 413                 retval = -ENODEV;
 414                 goto exit;
 415         }
 416
 417         if (down_interruptible(&dev->sem)) {
 418                 retval = -ERESTARTSYS;
 419                 goto exit;
 420         }
 421
 422         if (dev->open_count != 1) {
 423                 retval = -ENODEV;
 424                 goto unlock_exit;
 425         }
 426
 427         if (dev->intf == NULL) {
 428                 /* the device was unplugged before the file was released */
 429                 up(&dev->sem);
 430                 /* unlock here as usb_alphatrack_delete frees dev */
 431                 usb_alphatrack_delete(dev);
 432                 retval = -ENODEV;
 433                 goto exit;
 434         }
 435
 436         /* wait until write transfer is finished */
 437         if (dev->interrupt_out_busy)
 438                 wait_event_interruptible_timeout(dev->write_wait,
 439                                                  !dev->interrupt_out_busy,
 440                                                  2 * HZ);
 441         usb_alphatrack_abort_transfers(dev);
 442         dev->open_count = 0;
 443
 444 unlock_exit:
 445         up(&dev->sem);
 446
 447 exit:
 448         return retval;
 449 }
 450
 451 /**
 452  *      usb_alphatrack_poll
 453  */
 454 static unsigned int usb_alphatrack_poll(struct file *file, poll_table * wait)
 455 {
 456         struct usb_alphatrack *dev;
 457         unsigned int mask = 0;
 458
 459         dev = file->private_data;
 460
 461         poll_wait(file, &dev->read_wait, wait);
 462         poll_wait(file, &dev->write_wait, wait);
 463
 464         if (dev->ring_head != dev->ring_tail)
 465                 mask |= POLLIN | POLLRDNORM;
 466         if (!dev->interrupt_out_busy)
 467                 mask |= POLLOUT | POLLWRNORM;
 468
 469         return mask;
 470 }
 471
 472 /**
 473  *      usb_alphatrack_read
 474  */
 475 static ssize_t usb_alphatrack_read(struct file *file, char __user *buffer,
 476                                    size_t count, loff_t *ppos)
 477 {
 478         struct usb_alphatrack *dev;
 479         int retval = 0;
 480
 481         int c = 0;
 482
 483         dev = file->private_data;
 484
 485         /* verify that we actually have some data to read */
 486         if (count == 0)
 487                 goto exit;
 488
 489         /* lock this object */
 490         if (down_interruptible(&dev->sem)) {
 491                 retval = -ERESTARTSYS;
 492                 goto exit;
 493         }
 494
 495         /* verify that the device wasn't unplugged */
 496         if (dev->intf == NULL) {
 497                 retval = -ENODEV;
 498                 err("No device or device unplugged %d\n", retval);
 499                 goto unlock_exit;
 500         }
 501
 502         while (dev->ring_head == dev->ring_tail) {
 503                 if (file->f_flags & O_NONBLOCK) {
 504                         retval = -EAGAIN;
 505                         goto unlock_exit;
 506                 }
 507                 dev->interrupt_in_done = 0;
 508                 retval =
 509                     wait_event_interruptible(dev->read_wait,
 510                                              dev->interrupt_in_done);
 511                 if (retval < 0)
 512                         goto unlock_exit;
 513         }
 514
 515         alphatrack_ocmd_info(&dev->intf->dev,
 516                              &(*dev->ring_buffer)[dev->ring_tail].cmd, "%s",
 517                              ": copying to userspace");
 518
 519         c = 0;
 520         while ((c < count) && (dev->ring_tail != dev->ring_head)) {
 521                 if (copy_to_user
 522                     (&buffer[c], &(*dev->ring_buffer)[dev->ring_tail],
 523                      INPUT_CMD_SIZE)) {
 524                         retval = -EFAULT;
 525                         goto unlock_exit;
 526                 }
 527                 dev->ring_tail = (dev->ring_tail + 1) % ring_buffer_size;
 528                 c += INPUT_CMD_SIZE;
 529                 dbg_info(&dev->intf->dev, "%s: head, tail are %x, %x\n",
 530                          __func__, dev->ring_head, dev->ring_tail);
 531         }
 532         retval = c;
 533
 534 unlock_exit:
 535         /* unlock the device */
 536         up(&dev->sem);
 537
 538 exit:
 539         return retval;
 540 }
 541
 542 /**
 543  *      usb_alphatrack_write
 544  */
 545 static ssize_t usb_alphatrack_write(struct file *file,
 546                                     const char __user *buffer, size_t count,
 547                                     loff_t *ppos)
 548 {
 549         struct usb_alphatrack *dev;
 550         size_t bytes_to_write;
 551         int retval = 0;
 552
 553         dev = file->private_data;
 554
 555         /* verify that we actually have some data to write */
 556         if (count == 0)
 557                 goto exit;
 558
 559         /* lock this object */
 560         if (down_interruptible(&dev->sem)) {
 561                 retval = -ERESTARTSYS;
 562                 goto exit;
 563         }
 564
 565         /* verify that the device wasn't unplugged */
 566         if (dev->intf == NULL) {
 567                 retval = -ENODEV;
 568                 err("No device or device unplugged %d\n", retval);
 569                 goto unlock_exit;
 570         }
 571
 572         /* wait until previous transfer is finished */
 573         if (dev->interrupt_out_busy) {
 574                 if (file->f_flags & O_NONBLOCK) {
 575                         retval = -EAGAIN;
 576                         goto unlock_exit;
 577                 }
 578                 retval =
 579                     wait_event_interruptible(dev->write_wait,
 580                                              !dev->interrupt_out_busy);
 581                 if (retval < 0)
 582                         goto unlock_exit;
 583         }
 584
 585         /* write the data into interrupt_out_buffer from userspace */
 586         /* FIXME - if you write more than 12 bytes this breaks */
 587         bytes_to_write =
 588             min(count, write_buffer_size * dev->interrupt_out_endpoint_size);
 589         if (bytes_to_write < count)
 590                 dev_warn(&dev->intf->dev,
 591                          "Write buffer overflow, %zd bytes dropped\n",
 592                          count - bytes_to_write);
 593
 594         dbg_info(&dev->intf->dev, "%s: count = %zd, bytes_to_write = %zd\n",
 595                  __func__, count, bytes_to_write);
 596
 597         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 598                 retval = -EFAULT;
 599                 goto unlock_exit;
 600         }
 601
 602         if (dev->interrupt_out_endpoint == NULL) {
 603                 err("Endpoint should not be be null! \n");
 604                 goto unlock_exit;
 605         }
 606
 607         /* send off the urb */
 608         usb_fill_int_urb(dev->interrupt_out_urb,
 609                          interface_to_usbdev(dev->intf),
 610                          usb_sndintpipe(interface_to_usbdev(dev->intf),
 611                                         dev->interrupt_out_endpoint->
 612                                         bEndpointAddress),
 613                          dev->interrupt_out_buffer, bytes_to_write,
 614                          usb_alphatrack_interrupt_out_callback, dev,
 615                          dev->interrupt_out_interval);
 616         dev->interrupt_out_busy = 1;
 617         atomic_inc(&dev->writes_pending);
 618         wmb();
 619
 620         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 621         if (retval) {
 622                 dev->interrupt_out_busy = 0;
 623                 err("Couldn't submit interrupt_out_urb %d\n", retval);
 624                 atomic_dec(&dev->writes_pending);
 625                 goto unlock_exit;
 626         }
 627         retval = bytes_to_write;
 628
 629 unlock_exit:
 630         /* unlock the device */
 631         up(&dev->sem);
 632
 633 exit:
 634         return retval;
 635 }
 636
 637 /* file operations needed when we register this driver */
 638 static const struct file_operations usb_alphatrack_fops = {
 639         .owner = THIS_MODULE,
 640         .read = usb_alphatrack_read,
 641         .write = usb_alphatrack_write,
 642         .open = usb_alphatrack_open,
 643         .release = usb_alphatrack_release,
 644         .poll = usb_alphatrack_poll,
 645 };
 646
 647 /*
 648  * usb class driver info in order to get a minor number from the usb core,
 649  * and to have the device registered with the driver core
 650  */
 651
 652 static struct usb_class_driver usb_alphatrack_class = {
 653         .name = "alphatrack%d",
 654         .fops = &usb_alphatrack_fops,
 655         .minor_base = USB_ALPHATRACK_MINOR_BASE,
 656 };
 657
 658 /**
 659  *      usb_alphatrack_probe
 660  *
 661  *      Called by the usb core when a new device is connected that it thinks
 662  *      this driver might be interested in.
 663  */
 664 static int usb_alphatrack_probe(struct usb_interface *intf,
 665                                 const struct usb_device_id *id)
 666 {
 667         struct usb_device *udev = interface_to_usbdev(intf);
 668         struct usb_alphatrack *dev = NULL;
 669         struct usb_host_interface *iface_desc;
 670         struct usb_endpoint_descriptor *endpoint;
 671         int i;
 672         int true_size;
 673         int retval = -ENOMEM;
 674
 675         /* allocate memory for our device state and intialize it */
 676
 677         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 678         if (dev == NULL) {
 679                 dev_err(&intf->dev, "Out of memory\n");
 680                 goto exit;
 681         }
 682         init_MUTEX(&dev->sem);
 683         dev->intf = intf;
 684         init_waitqueue_head(&dev->read_wait);
 685         init_waitqueue_head(&dev->write_wait);
 686
 687         iface_desc = intf->cur_altsetting;
 688
 689         /* set up the endpoint information */
 690         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
 691                 endpoint = &iface_desc->endpoint[i].desc;
 692
 693                 if (usb_endpoint_is_int_in(endpoint))
 694                         dev->interrupt_in_endpoint = endpoint;
 695
 696                 if (usb_endpoint_is_int_out(endpoint))
 697                         dev->interrupt_out_endpoint = endpoint;
 698         }
 699         if (dev->interrupt_in_endpoint == NULL) {
 700                 dev_err(&intf->dev, "Interrupt in endpoint not found\n");
 701                 goto error;
 702         }
 703         if (dev->interrupt_out_endpoint == NULL)
 704                 dev_warn(&intf->dev,
 705                          "Interrupt out endpoint not found"
 706                          "(using control endpoint instead)\n");
 707
 708         dev->interrupt_in_endpoint_size =
 709             le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize);
 710
 711         if (dev->interrupt_in_endpoint_size != 64)
 712                 dev_warn(&intf->dev, "Interrupt in endpoint size is not 64!\n");
 713
 714         if (ring_buffer_size == 0)
 715                 ring_buffer_size = RING_BUFFER_SIZE;
 716
 717         true_size = min(ring_buffer_size, RING_BUFFER_SIZE);
 718
 719         /* FIXME - there are more usb_alloc routines for dma correctness.
 720            Needed? */
 721         dev->ring_buffer =
 722             kmalloc((true_size * sizeof(struct alphatrack_icmd)), GFP_KERNEL);
 723
 724         if (!dev->ring_buffer) {
 725                 dev_err(&intf->dev,
 726                         "Couldn't allocate input ring_buffer of size %d\n",
 727                         true_size);
 728                 goto error;
 729         }
 730
 731         dev->interrupt_in_buffer =
 732             kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 733
 734         if (!dev->interrupt_in_buffer) {
 735                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_buffer\n");
 736                 goto error;
 737         }
 738         dev->oldi_buffer = kmalloc(dev->interrupt_in_endpoint_size, GFP_KERNEL);
 739         if (!dev->oldi_buffer) {
 740                 dev_err(&intf->dev, "Couldn't allocate old buffer\n");
 741                 goto error;
 742         }
 743         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 744         if (!dev->interrupt_in_urb) {
 745                 dev_err(&intf->dev, "Couldn't allocate interrupt_in_urb\n");
 746                 goto error;
 747         }
 748
 749         dev->interrupt_out_endpoint_size =
 750             dev->interrupt_out_endpoint ? le16_to_cpu(dev->
 751                                                       interrupt_out_endpoint->
 752                                                       wMaxPacketSize) : udev->
 753             descriptor.bMaxPacketSize0;
 754
 755         if (dev->interrupt_out_endpoint_size != 64)
 756                 dev_warn(&intf->dev,
 757                          "Interrupt out endpoint size is not 64!)\n");
 758
 759         if (write_buffer_size == 0)
 760                 write_buffer_size = WRITE_BUFFER_SIZE;
 761         true_size = min(write_buffer_size, WRITE_BUFFER_SIZE);
 762
 763         dev->interrupt_out_buffer =
 764             kmalloc(true_size * dev->interrupt_out_endpoint_size, GFP_KERNEL);
 765
 766         if (!dev->interrupt_out_buffer) {
 767                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_buffer\n");
 768                 goto error;
 769         }
 770
 771         dev->write_buffer =
 772             kmalloc(sizeof(struct alphatrack_ocmd) * true_size, GFP_KERNEL);
 773
 774         if (!dev->write_buffer) {
 775                 dev_err(&intf->dev, "Couldn't allocate write_buffer \n");
 776                 goto error;
 777         }
 778
 779         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 780         if (!dev->interrupt_out_urb) {
 781                 dev_err(&intf->dev, "Couldn't allocate interrupt_out_urb\n");
 782                 goto error;
 783         }
 784         dev->interrupt_in_interval =
 785             min_interrupt_in_interval >
 786             dev->interrupt_in_endpoint->
 787             bInterval ? min_interrupt_in_interval : dev->interrupt_in_endpoint->
 788             bInterval;
 789         if (dev->interrupt_out_endpoint)
 790                 dev->interrupt_out_interval =
 791                     min_interrupt_out_interval >
 792                     dev->interrupt_out_endpoint->
 793                     bInterval ? min_interrupt_out_interval : dev->
 794                     interrupt_out_endpoint->bInterval;
 795
 796         /* we can register the device now, as it is ready */
 797         usb_set_intfdata(intf, dev);
 798
 799         atomic_set(&dev->writes_pending, 0);
 800         retval = usb_register_dev(intf, &usb_alphatrack_class);
 801         if (retval) {
 802                 /* something prevented us from registering this driver */
 803                 dev_err(&intf->dev,
 804                         "Not able to get a minor for this device.\n");
 805                 usb_set_intfdata(intf, NULL);
 806                 goto error;
 807         }
 808
 809         /* let the user know what node this device is now attached to */
 810         dev_info(&intf->dev,
 811                  "Alphatrack Device #%d now attached to major %d minor %d\n",
 812                  (intf->minor - USB_ALPHATRACK_MINOR_BASE), USB_MAJOR,
 813                  intf->minor);
 814
 815 exit:
 816         return retval;
 817
 818 error:
 819         usb_alphatrack_delete(dev);
 820
 821         return retval;
 822 }
 823
 824 /**
 825  *      usb_alphatrack_disconnect
 826  *
 827  *      Called by the usb core when the device is removed from the system.
 828  */
 829 static void usb_alphatrack_disconnect(struct usb_interface *intf)
 830 {
 831         struct usb_alphatrack *dev;
 832         int minor;
 833
 834         mutex_lock(&disconnect_mutex);
 835
 836         dev = usb_get_intfdata(intf);
 837         usb_set_intfdata(intf, NULL);
 838
 839         down(&dev->sem);
 840
 841         minor = intf->minor;
 842
 843         /* give back our minor */
 844         usb_deregister_dev(intf, &usb_alphatrack_class);
 845
 846         /* if the device is not opened, then we clean up right now */
 847         if (!dev->open_count) {
 848                 up(&dev->sem);
 849                 usb_alphatrack_delete(dev);
 850         } else {
 851                 dev->intf = NULL;
 852                 up(&dev->sem);
 853         }
 854
 855         atomic_set(&dev->writes_pending, 0);
 856         mutex_unlock(&disconnect_mutex);
 857
 858         dev_info(&intf->dev, "Alphatrack Surface #%d now disconnected\n",
 859                  (minor - USB_ALPHATRACK_MINOR_BASE));
 860 }
 861
 862 /* usb specific object needed to register this driver with the usb subsystem */
 863 static struct usb_driver usb_alphatrack_driver = {
 864         .name = "alphatrack",
 865         .probe = usb_alphatrack_probe,
 866         .disconnect = usb_alphatrack_disconnect,
 867         .id_table = usb_alphatrack_table,
 868 };
 869
 870 /**
 871  *      usb_alphatrack_init
 872  */
 873 static int __init usb_alphatrack_init(void)
 874 {
 875         int retval;
 876
 877         /* register this driver with the USB subsystem */
 878         retval = usb_register(&usb_alphatrack_driver);
 879         if (retval)
 880                 err("usb_register failed for the " __FILE__
 881                     " driver. Error number %d\n", retval);
 882
 883         return retval;
 884 }
 885
 886 /**
 887  *      usb_alphatrack_exit
 888  */
 889 static void __exit usb_alphatrack_exit(void)
 890 {
 891         /* deregister this driver with the USB subsystem */
 892         usb_deregister(&usb_alphatrack_driver);
 893 }
 894
 895 module_init(usb_alphatrack_init);
 896 module_exit(usb_alphatrack_exit);