drivers/usb/misc/legousbtower.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * LEGO USB Tower driver
   4  *
   5  * Copyright (C) 2003 David Glance <davidgsf@sourceforge.net>
   6  *               2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
   7  *
   8  * derived from USB Skeleton driver - 0.5
   9  * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
  10  *
  11  * History:
  12  *
  13  * 2001-10-13 - 0.1 js
  14  *   - first version
  15  * 2001-11-03 - 0.2 js
  16  *   - simplified buffering, one-shot URBs for writing
  17  * 2001-11-10 - 0.3 js
  18  *   - removed IOCTL (setting power/mode is more complicated, postponed)
  19  * 2001-11-28 - 0.4 js
  20  *   - added vendor commands for mode of operation and power level in open
  21  * 2001-12-04 - 0.5 js
  22  *   - set IR mode by default (by oversight 0.4 set VLL mode)
  23  * 2002-01-11 - 0.5? pcchan
  24  *   - make read buffer reusable and work around bytes_to_write issue between
  25  *     uhci and legusbtower
  26  * 2002-09-23 - 0.52 david (david@csse.uwa.edu.au)
  27  *   - imported into lejos project
  28  *   - changed wake_up to wake_up_interruptible
  29  *   - changed to use lego0 rather than tower0
  30  *   - changed dbg() to use __func__ rather than deprecated __func__
  31  * 2003-01-12 - 0.53 david (david@csse.uwa.edu.au)
  32  *   - changed read and write to write everything or
  33  *     timeout (from a patch by Chris Riesen and Brett Thaeler driver)
  34  *   - added ioctl functionality to set timeouts
  35  * 2003-07-18 - 0.54 davidgsf (david@csse.uwa.edu.au)
  36  *   - initial import into LegoUSB project
  37  *   - merge of existing LegoUSB.c driver
  38  * 2003-07-18 - 0.56 davidgsf (david@csse.uwa.edu.au)
  39  *   - port to 2.6 style driver
  40  * 2004-02-29 - 0.6 Juergen Stuber <starblue@users.sourceforge.net>
  41  *   - fix locking
  42  *   - unlink read URBs which are no longer needed
  43  *   - allow increased buffer size, eliminates need for timeout on write
  44  *   - have read URB running continuously
  45  *   - added poll
  46  *   - forbid seeking
  47  *   - added nonblocking I/O
  48  *   - changed back __func__ to __func__
  49  *   - read and log tower firmware version
  50  *   - reset tower on probe, avoids failure of first write
  51  * 2004-03-09 - 0.7 Juergen Stuber <starblue@users.sourceforge.net>
  52  *   - timeout read now only after inactivity, shorten default accordingly
  53  * 2004-03-11 - 0.8 Juergen Stuber <starblue@users.sourceforge.net>
  54  *   - log major, minor instead of possibly confusing device filename
  55  *   - whitespace cleanup
  56  * 2004-03-12 - 0.9 Juergen Stuber <starblue@users.sourceforge.net>
  57  *   - normalize whitespace in debug messages
  58  *   - take care about endianness in control message responses
  59  * 2004-03-13 - 0.91 Juergen Stuber <starblue@users.sourceforge.net>
  60  *   - make default intervals longer to accommodate current EHCI driver
  61  * 2004-03-19 - 0.92 Juergen Stuber <starblue@users.sourceforge.net>
  62  *   - replaced atomic_t by memory barriers
  63  * 2004-04-21 - 0.93 Juergen Stuber <starblue@users.sourceforge.net>
  64  *   - wait for completion of write urb in release (needed for remotecontrol)
  65  *   - corrected poll for write direction (missing negation)
  66  * 2004-04-22 - 0.94 Juergen Stuber <starblue@users.sourceforge.net>
  67  *   - make device locking interruptible
  68  * 2004-04-30 - 0.95 Juergen Stuber <starblue@users.sourceforge.net>
  69  *   - check for valid udev on resubmitting and unlinking urbs
  70  * 2004-08-03 - 0.96 Juergen Stuber <starblue@users.sourceforge.net>
  71  *   - move reset into open to clean out spurious data
  72  */
  73
  74 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  75
  76 #include <linux/kernel.h>
  77 #include <linux/errno.h>
  78 #include <linux/slab.h>
  79 #include <linux/module.h>
  80 #include <linux/completion.h>
  81 #include <linux/mutex.h>
  82 #include <linux/uaccess.h>
  83 #include <linux/usb.h>
  84 #include <linux/poll.h>
  85
  86
  87 #define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
  88 #define DRIVER_DESC "LEGO USB Tower Driver"
  89
  90
  91 /* The defaults are chosen to work with the latest versions of leJOS and NQC.
  92  */
  93
  94 /* Some legacy software likes to receive packets in one piece.
  95  * In this case read_buffer_size should exceed the maximal packet length
  96  * (417 for datalog uploads), and packet_timeout should be set.
  97  */
  98 static int read_buffer_size = 480;
  99 module_param(read_buffer_size, int, 0);
 100 MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
 101
 102 /* Some legacy software likes to send packets in one piece.
 103  * In this case write_buffer_size should exceed the maximal packet length
 104  * (417 for firmware and program downloads).
 105  * A problem with long writes is that the following read may time out
 106  * if the software is not prepared to wait long enough.
 107  */
 108 static int write_buffer_size = 480;
 109 module_param(write_buffer_size, int, 0);
 110 MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
 111
 112 /* Some legacy software expects reads to contain whole LASM packets.
 113  * To achieve this, characters which arrive before a packet timeout
 114  * occurs will be returned in a single read operation.
 115  * A problem with long reads is that the software may time out
 116  * if it is not prepared to wait long enough.
 117  * The packet timeout should be greater than the time between the
 118  * reception of subsequent characters, which should arrive about
 119  * every 5ms for the standard 2400 baud.
 120  * Set it to 0 to disable.
 121  */
 122 static int packet_timeout = 50;
 123 module_param(packet_timeout, int, 0);
 124 MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
 125
 126 /* Some legacy software expects blocking reads to time out.
 127  * Timeout occurs after the specified time of read and write inactivity.
 128  * Set it to 0 to disable.
 129  */
 130 static int read_timeout = 200;
 131 module_param(read_timeout, int, 0);
 132 MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
 133
 134 /* As of kernel version 2.6.4 ehci-hcd uses an
 135  * "only one interrupt transfer per frame" shortcut
 136  * to simplify the scheduling of periodic transfers.
 137  * This conflicts with our standard 1ms intervals for in and out URBs.
 138  * We use default intervals of 2ms for in and 8ms for out transfers,
 139  * which is fast enough for 2400 baud and allows a small additional load.
 140  * Increase the interval to allow more devices that do interrupt transfers,
 141  * or set to 0 to use the standard interval from the endpoint descriptors.
 142  */
 143 static int interrupt_in_interval = 2;
 144 module_param(interrupt_in_interval, int, 0);
 145 MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
 146
 147 static int interrupt_out_interval = 8;
 148 module_param(interrupt_out_interval, int, 0);
 149 MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
 150
 151 /* Define these values to match your device */
 152 #define LEGO_USB_TOWER_VENDOR_ID        0x0694
 153 #define LEGO_USB_TOWER_PRODUCT_ID       0x0001
 154
 155 /* Vendor requests */
 156 #define LEGO_USB_TOWER_REQUEST_RESET            0x04
 157 #define LEGO_USB_TOWER_REQUEST_GET_VERSION      0xFD
 158
 159 struct tower_reset_reply {
 160         __le16 size;
 161         __u8 err_code;
 162         __u8 spare;
 163 };
 164
 165 struct tower_get_version_reply {
 166         __le16 size;
 167         __u8 err_code;
 168         __u8 spare;
 169         __u8 major;
 170         __u8 minor;
 171         __le16 build_no;
 172 };
 173
 174
 175 /* table of devices that work with this driver */
 176 static const struct usb_device_id tower_table[] = {
 177         { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
 178         { }                                     /* Terminating entry */
 179 };
 180
 181 MODULE_DEVICE_TABLE(usb, tower_table);
 182
 183 #define LEGO_USB_TOWER_MINOR_BASE       160
 184
 185
 186 /* Structure to hold all of our device specific stuff */
 187 struct lego_usb_tower {
 188         struct mutex            lock;           /* locks this structure */
 189         struct usb_device       *udev;          /* save off the usb device pointer */
 190         unsigned char           minor;          /* the starting minor number for this device */
 191
 192         int                     open_count;     /* number of times this port has been opened */
 193         unsigned long           disconnected:1;
 194
 195         char                    *read_buffer;
 196         size_t                  read_buffer_length; /* this much came in */
 197         size_t                  read_packet_length; /* this much will be returned on read */
 198         spinlock_t              read_buffer_lock;
 199         int                     packet_timeout_jiffies;
 200         unsigned long           read_last_arrival;
 201
 202         wait_queue_head_t       read_wait;
 203         wait_queue_head_t       write_wait;
 204
 205         char                    *interrupt_in_buffer;
 206         struct usb_endpoint_descriptor *interrupt_in_endpoint;
 207         struct urb              *interrupt_in_urb;
 208         int                     interrupt_in_interval;
 209         int                     interrupt_in_done;
 210
 211         char                    *interrupt_out_buffer;
 212         struct usb_endpoint_descriptor *interrupt_out_endpoint;
 213         struct urb              *interrupt_out_urb;
 214         int                     interrupt_out_interval;
 215         int                     interrupt_out_busy;
 216
 217 };
 218
 219
 220 /* local function prototypes */
 221 static ssize_t tower_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos);
 222 static ssize_t tower_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
 223 static inline void tower_delete(struct lego_usb_tower *dev);
 224 static int tower_open(struct inode *inode, struct file *file);
 225 static int tower_release(struct inode *inode, struct file *file);
 226 static __poll_t tower_poll(struct file *file, poll_table *wait);
 227 static loff_t tower_llseek(struct file *file, loff_t off, int whence);
 228
 229 static void tower_check_for_read_packet(struct lego_usb_tower *dev);
 230 static void tower_interrupt_in_callback(struct urb *urb);
 231 static void tower_interrupt_out_callback(struct urb *urb);
 232
 233 static int  tower_probe(struct usb_interface *interface, const struct usb_device_id *id);
 234 static void tower_disconnect(struct usb_interface *interface);
 235
 236
 237 /* file operations needed when we register this driver */
 238 static const struct file_operations tower_fops = {
 239         .owner =        THIS_MODULE,
 240         .read  =        tower_read,
 241         .write =        tower_write,
 242         .open =         tower_open,
 243         .release =      tower_release,
 244         .poll =         tower_poll,
 245         .llseek =       tower_llseek,
 246 };
 247
 248 static char *legousbtower_devnode(struct device *dev, umode_t *mode)
 249 {
 250         return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
 251 }
 252
 253 /*
 254  * usb class driver info in order to get a minor number from the usb core,
 255  * and to have the device registered with the driver core
 256  */
 257 static struct usb_class_driver tower_class = {
 258         .name =         "legousbtower%d",
 259         .devnode =      legousbtower_devnode,
 260         .fops =         &tower_fops,
 261         .minor_base =   LEGO_USB_TOWER_MINOR_BASE,
 262 };
 263
 264
 265 /* usb specific object needed to register this driver with the usb subsystem */
 266 static struct usb_driver tower_driver = {
 267         .name =         "legousbtower",
 268         .probe =        tower_probe,
 269         .disconnect =   tower_disconnect,
 270         .id_table =     tower_table,
 271 };
 272
 273
 274 /*
 275  *      lego_usb_tower_debug_data
 276  */
 277 static inline void lego_usb_tower_debug_data(struct device *dev,
 278                                              const char *function, int size,
 279                                              const unsigned char *data)
 280 {
 281         dev_dbg(dev, "%s - length = %d, data = %*ph\n",
 282                 function, size, size, data);
 283 }
 284
 285
 286 /*
 287  *      tower_delete
 288  */
 289 static inline void tower_delete(struct lego_usb_tower *dev)
 290 {
 291         /* free data structures */
 292         usb_free_urb(dev->interrupt_in_urb);
 293         usb_free_urb(dev->interrupt_out_urb);
 294         kfree(dev->read_buffer);
 295         kfree(dev->interrupt_in_buffer);
 296         kfree(dev->interrupt_out_buffer);
 297         usb_put_dev(dev->udev);
 298         kfree(dev);
 299 }
 300
 301
 302 /*
 303  *      tower_open
 304  */
 305 static int tower_open(struct inode *inode, struct file *file)
 306 {
 307         struct lego_usb_tower *dev = NULL;
 308         int subminor;
 309         int retval = 0;
 310         struct usb_interface *interface;
 311         struct tower_reset_reply *reset_reply;
 312         int result;
 313
 314         reset_reply = kmalloc(sizeof(*reset_reply), GFP_KERNEL);
 315         if (!reset_reply) {
 316                 retval = -ENOMEM;
 317                 goto exit;
 318         }
 319
 320         nonseekable_open(inode, file);
 321         subminor = iminor(inode);
 322
 323         interface = usb_find_interface(&tower_driver, subminor);
 324         if (!interface) {
 325                 pr_err("error, can't find device for minor %d\n", subminor);
 326                 retval = -ENODEV;
 327                 goto exit;
 328         }
 329
 330         dev = usb_get_intfdata(interface);
 331         if (!dev) {
 332                 retval = -ENODEV;
 333                 goto exit;
 334         }
 335
 336         /* lock this device */
 337         if (mutex_lock_interruptible(&dev->lock)) {
 338                 retval = -ERESTARTSYS;
 339                 goto exit;
 340         }
 341
 342
 343         /* allow opening only once */
 344         if (dev->open_count) {
 345                 retval = -EBUSY;
 346                 goto unlock_exit;
 347         }
 348
 349         /* reset the tower */
 350         result = usb_control_msg(dev->udev,
 351                                  usb_rcvctrlpipe(dev->udev, 0),
 352                                  LEGO_USB_TOWER_REQUEST_RESET,
 353                                  USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 354                                  0,
 355                                  0,
 356                                  reset_reply,
 357                                  sizeof(*reset_reply),
 358                                  1000);
 359         if (result < 0) {
 360                 dev_err(&dev->udev->dev,
 361                         "LEGO USB Tower reset control request failed\n");
 362                 retval = result;
 363                 goto unlock_exit;
 364         }
 365
 366         /* initialize in direction */
 367         dev->read_buffer_length = 0;
 368         dev->read_packet_length = 0;
 369         usb_fill_int_urb(dev->interrupt_in_urb,
 370                          dev->udev,
 371                          usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
 372                          dev->interrupt_in_buffer,
 373                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 374                          tower_interrupt_in_callback,
 375                          dev,
 376                          dev->interrupt_in_interval);
 377
 378         dev->interrupt_in_done = 0;
 379         mb();
 380
 381         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 382         if (retval) {
 383                 dev_err(&dev->udev->dev,
 384                         "Couldn't submit interrupt_in_urb %d\n", retval);
 385                 goto unlock_exit;
 386         }
 387
 388         /* save device in the file's private structure */
 389         file->private_data = dev;
 390
 391         dev->open_count = 1;
 392
 393 unlock_exit:
 394         mutex_unlock(&dev->lock);
 395
 396 exit:
 397         kfree(reset_reply);
 398         return retval;
 399 }
 400
 401 /*
 402  *      tower_release
 403  */
 404 static int tower_release(struct inode *inode, struct file *file)
 405 {
 406         struct lego_usb_tower *dev;
 407         int retval = 0;
 408
 409         dev = file->private_data;
 410         if (dev == NULL) {
 411                 retval = -ENODEV;
 412                 goto exit;
 413         }
 414
 415         mutex_lock(&dev->lock);
 416
 417         if (dev->disconnected) {
 418                 /* the device was unplugged before the file was released */
 419
 420                 /* unlock here as tower_delete frees dev */
 421                 mutex_unlock(&dev->lock);
 422                 tower_delete(dev);
 423                 goto exit;
 424         }
 425
 426         /* wait until write transfer is finished */
 427         if (dev->interrupt_out_busy) {
 428                 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy,
 429                                                  2 * HZ);
 430         }
 431
 432         /* shutdown transfers */
 433         usb_kill_urb(dev->interrupt_in_urb);
 434         usb_kill_urb(dev->interrupt_out_urb);
 435
 436         dev->open_count = 0;
 437
 438         mutex_unlock(&dev->lock);
 439 exit:
 440         return retval;
 441 }
 442
 443 /*
 444  *      tower_check_for_read_packet
 445  *
 446  *      To get correct semantics for signals and non-blocking I/O
 447  *      with packetizing we pretend not to see any data in the read buffer
 448  *      until it has been there unchanged for at least
 449  *      dev->packet_timeout_jiffies, or until the buffer is full.
 450  */
 451 static void tower_check_for_read_packet(struct lego_usb_tower *dev)
 452 {
 453         spin_lock_irq(&dev->read_buffer_lock);
 454         if (!packet_timeout
 455             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
 456             || dev->read_buffer_length == read_buffer_size) {
 457                 dev->read_packet_length = dev->read_buffer_length;
 458         }
 459         dev->interrupt_in_done = 0;
 460         spin_unlock_irq(&dev->read_buffer_lock);
 461 }
 462
 463
 464 /*
 465  *      tower_poll
 466  */
 467 static __poll_t tower_poll(struct file *file, poll_table *wait)
 468 {
 469         struct lego_usb_tower *dev;
 470         __poll_t mask = 0;
 471
 472         dev = file->private_data;
 473
 474         if (dev->disconnected)
 475                 return EPOLLERR | EPOLLHUP;
 476
 477         poll_wait(file, &dev->read_wait, wait);
 478         poll_wait(file, &dev->write_wait, wait);
 479
 480         tower_check_for_read_packet(dev);
 481         if (dev->read_packet_length > 0)
 482                 mask |= EPOLLIN | EPOLLRDNORM;
 483         if (!dev->interrupt_out_busy)
 484                 mask |= EPOLLOUT | EPOLLWRNORM;
 485
 486         return mask;
 487 }
 488
 489
 490 /*
 491  *      tower_llseek
 492  */
 493 static loff_t tower_llseek(struct file *file, loff_t off, int whence)
 494 {
 495         return -ESPIPE;         /* unseekable */
 496 }
 497
 498
 499 /*
 500  *      tower_read
 501  */
 502 static ssize_t tower_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 503 {
 504         struct lego_usb_tower *dev;
 505         size_t bytes_to_read;
 506         int i;
 507         int retval = 0;
 508         unsigned long timeout = 0;
 509
 510         dev = file->private_data;
 511
 512         /* lock this object */
 513         if (mutex_lock_interruptible(&dev->lock)) {
 514                 retval = -ERESTARTSYS;
 515                 goto exit;
 516         }
 517
 518         /* verify that the device wasn't unplugged */
 519         if (dev->disconnected) {
 520                 retval = -ENODEV;
 521                 goto unlock_exit;
 522         }
 523
 524         /* verify that we actually have some data to read */
 525         if (count == 0) {
 526                 dev_dbg(&dev->udev->dev, "read request of 0 bytes\n");
 527                 goto unlock_exit;
 528         }
 529
 530         if (read_timeout)
 531                 timeout = jiffies + msecs_to_jiffies(read_timeout);
 532
 533         /* wait for data */
 534         tower_check_for_read_packet(dev);
 535         while (dev->read_packet_length == 0) {
 536                 if (file->f_flags & O_NONBLOCK) {
 537                         retval = -EAGAIN;
 538                         goto unlock_exit;
 539                 }
 540                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
 541                 if (retval < 0)
 542                         goto unlock_exit;
 543
 544                 /* reset read timeout during read or write activity */
 545                 if (read_timeout
 546                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
 547                         timeout = jiffies + msecs_to_jiffies(read_timeout);
 548                 }
 549                 /* check for read timeout */
 550                 if (read_timeout && time_after(jiffies, timeout)) {
 551                         retval = -ETIMEDOUT;
 552                         goto unlock_exit;
 553                 }
 554                 tower_check_for_read_packet(dev);
 555         }
 556
 557         /* copy the data from read_buffer into userspace */
 558         bytes_to_read = min(count, dev->read_packet_length);
 559
 560         if (copy_to_user(buffer, dev->read_buffer, bytes_to_read)) {
 561                 retval = -EFAULT;
 562                 goto unlock_exit;
 563         }
 564
 565         spin_lock_irq(&dev->read_buffer_lock);
 566         dev->read_buffer_length -= bytes_to_read;
 567         dev->read_packet_length -= bytes_to_read;
 568         for (i = 0; i < dev->read_buffer_length; i++)
 569                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
 570         spin_unlock_irq(&dev->read_buffer_lock);
 571
 572         retval = bytes_to_read;
 573
 574 unlock_exit:
 575         /* unlock the device */
 576         mutex_unlock(&dev->lock);
 577
 578 exit:
 579         return retval;
 580 }
 581
 582
 583 /*
 584  *      tower_write
 585  */
 586 static ssize_t tower_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 587 {
 588         struct lego_usb_tower *dev;
 589         size_t bytes_to_write;
 590         int retval = 0;
 591
 592         dev = file->private_data;
 593
 594         /* lock this object */
 595         if (mutex_lock_interruptible(&dev->lock)) {
 596                 retval = -ERESTARTSYS;
 597                 goto exit;
 598         }
 599
 600         /* verify that the device wasn't unplugged */
 601         if (dev->disconnected) {
 602                 retval = -ENODEV;
 603                 goto unlock_exit;
 604         }
 605
 606         /* verify that we actually have some data to write */
 607         if (count == 0) {
 608                 dev_dbg(&dev->udev->dev, "write request of 0 bytes\n");
 609                 goto unlock_exit;
 610         }
 611
 612         /* wait until previous transfer is finished */
 613         while (dev->interrupt_out_busy) {
 614                 if (file->f_flags & O_NONBLOCK) {
 615                         retval = -EAGAIN;
 616                         goto unlock_exit;
 617                 }
 618                 retval = wait_event_interruptible(dev->write_wait,
 619                                                   !dev->interrupt_out_busy);
 620                 if (retval)
 621                         goto unlock_exit;
 622         }
 623
 624         /* write the data into interrupt_out_buffer from userspace */
 625         bytes_to_write = min_t(int, count, write_buffer_size);
 626         dev_dbg(&dev->udev->dev, "%s: count = %zd, bytes_to_write = %zd\n",
 627                 __func__, count, bytes_to_write);
 628
 629         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 630                 retval = -EFAULT;
 631                 goto unlock_exit;
 632         }
 633
 634         /* send off the urb */
 635         usb_fill_int_urb(dev->interrupt_out_urb,
 636                          dev->udev,
 637                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 638                          dev->interrupt_out_buffer,
 639                          bytes_to_write,
 640                          tower_interrupt_out_callback,
 641                          dev,
 642                          dev->interrupt_out_interval);
 643
 644         dev->interrupt_out_busy = 1;
 645         wmb();
 646
 647         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 648         if (retval) {
 649                 dev->interrupt_out_busy = 0;
 650                 dev_err(&dev->udev->dev,
 651                         "Couldn't submit interrupt_out_urb %d\n", retval);
 652                 goto unlock_exit;
 653         }
 654         retval = bytes_to_write;
 655
 656 unlock_exit:
 657         /* unlock the device */
 658         mutex_unlock(&dev->lock);
 659
 660 exit:
 661         return retval;
 662 }
 663
 664
 665 /*
 666  *      tower_interrupt_in_callback
 667  */
 668 static void tower_interrupt_in_callback(struct urb *urb)
 669 {
 670         struct lego_usb_tower *dev = urb->context;
 671         int status = urb->status;
 672         int retval;
 673         unsigned long flags;
 674
 675         lego_usb_tower_debug_data(&dev->udev->dev, __func__,
 676                                   urb->actual_length, urb->transfer_buffer);
 677
 678         if (status) {
 679                 if (status == -ENOENT ||
 680                     status == -ECONNRESET ||
 681                     status == -ESHUTDOWN) {
 682                         goto exit;
 683                 } else {
 684                         dev_dbg(&dev->udev->dev,
 685                                 "%s: nonzero status received: %d\n", __func__,
 686                                 status);
 687                         goto resubmit; /* maybe we can recover */
 688                 }
 689         }
 690
 691         if (urb->actual_length > 0) {
 692                 spin_lock_irqsave(&dev->read_buffer_lock, flags);
 693                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
 694                         memcpy(dev->read_buffer + dev->read_buffer_length,
 695                                dev->interrupt_in_buffer,
 696                                urb->actual_length);
 697                         dev->read_buffer_length += urb->actual_length;
 698                         dev->read_last_arrival = jiffies;
 699                         dev_dbg(&dev->udev->dev, "%s: received %d bytes\n",
 700                                 __func__, urb->actual_length);
 701                 } else {
 702                         pr_warn("read_buffer overflow, %d bytes dropped\n",
 703                                 urb->actual_length);
 704                 }
 705                 spin_unlock_irqrestore(&dev->read_buffer_lock, flags);
 706         }
 707
 708 resubmit:
 709         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 710         if (retval) {
 711                 dev_err(&dev->udev->dev, "%s: usb_submit_urb failed (%d)\n",
 712                         __func__, retval);
 713         }
 714 exit:
 715         dev->interrupt_in_done = 1;
 716         wake_up_interruptible(&dev->read_wait);
 717 }
 718
 719
 720 /*
 721  *      tower_interrupt_out_callback
 722  */
 723 static void tower_interrupt_out_callback(struct urb *urb)
 724 {
 725         struct lego_usb_tower *dev = urb->context;
 726         int status = urb->status;
 727
 728         lego_usb_tower_debug_data(&dev->udev->dev, __func__,
 729                                   urb->actual_length, urb->transfer_buffer);
 730
 731         /* sync/async unlink faults aren't errors */
 732         if (status && !(status == -ENOENT ||
 733                         status == -ECONNRESET ||
 734                         status == -ESHUTDOWN)) {
 735                 dev_dbg(&dev->udev->dev,
 736                         "%s: nonzero write bulk status received: %d\n", __func__,
 737                         status);
 738         }
 739
 740         dev->interrupt_out_busy = 0;
 741         wake_up_interruptible(&dev->write_wait);
 742 }
 743
 744
 745 /*
 746  *      tower_probe
 747  *
 748  *      Called by the usb core when a new device is connected that it thinks
 749  *      this driver might be interested in.
 750  */
 751 static int tower_probe(struct usb_interface *interface, const struct usb_device_id *id)
 752 {
 753         struct device *idev = &interface->dev;
 754         struct usb_device *udev = interface_to_usbdev(interface);
 755         struct lego_usb_tower *dev;
 756         struct tower_get_version_reply *get_version_reply = NULL;
 757         int retval = -ENOMEM;
 758         int result;
 759
 760         /* allocate memory for our device state and initialize it */
 761         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 762         if (!dev)
 763                 goto exit;
 764
 765         mutex_init(&dev->lock);
 766         dev->udev = usb_get_dev(udev);
 767         spin_lock_init(&dev->read_buffer_lock);
 768         dev->packet_timeout_jiffies = msecs_to_jiffies(packet_timeout);
 769         dev->read_last_arrival = jiffies;
 770         init_waitqueue_head(&dev->read_wait);
 771         init_waitqueue_head(&dev->write_wait);
 772
 773         result = usb_find_common_endpoints_reverse(interface->cur_altsetting,
 774                         NULL, NULL,
 775                         &dev->interrupt_in_endpoint,
 776                         &dev->interrupt_out_endpoint);
 777         if (result) {
 778                 dev_err(idev, "interrupt endpoints not found\n");
 779                 retval = result;
 780                 goto error;
 781         }
 782
 783         dev->read_buffer = kmalloc(read_buffer_size, GFP_KERNEL);
 784         if (!dev->read_buffer)
 785                 goto error;
 786         dev->interrupt_in_buffer = kmalloc(usb_endpoint_maxp(dev->interrupt_in_endpoint), GFP_KERNEL);
 787         if (!dev->interrupt_in_buffer)
 788                 goto error;
 789         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 790         if (!dev->interrupt_in_urb)
 791                 goto error;
 792         dev->interrupt_out_buffer = kmalloc(write_buffer_size, GFP_KERNEL);
 793         if (!dev->interrupt_out_buffer)
 794                 goto error;
 795         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 796         if (!dev->interrupt_out_urb)
 797                 goto error;
 798         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 799         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 800
 801         get_version_reply = kmalloc(sizeof(*get_version_reply), GFP_KERNEL);
 802         if (!get_version_reply) {
 803                 retval = -ENOMEM;
 804                 goto error;
 805         }
 806
 807         /* get the firmware version and log it */
 808         result = usb_control_msg(udev,
 809                                  usb_rcvctrlpipe(udev, 0),
 810                                  LEGO_USB_TOWER_REQUEST_GET_VERSION,
 811                                  USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 812                                  0,
 813                                  0,
 814                                  get_version_reply,
 815                                  sizeof(*get_version_reply),
 816                                  1000);
 817         if (result != sizeof(*get_version_reply)) {
 818                 if (result >= 0)
 819                         result = -EIO;
 820                 dev_err(idev, "get version request failed: %d\n", result);
 821                 retval = result;
 822                 goto error;
 823         }
 824         dev_info(&interface->dev,
 825                  "LEGO USB Tower firmware version is %d.%d build %d\n",
 826                  get_version_reply->major,
 827                  get_version_reply->minor,
 828                  le16_to_cpu(get_version_reply->build_no));
 829
 830         /* we can register the device now, as it is ready */
 831         usb_set_intfdata(interface, dev);
 832
 833         retval = usb_register_dev(interface, &tower_class);
 834         if (retval) {
 835                 /* something prevented us from registering this driver */
 836                 dev_err(idev, "Not able to get a minor for this device.\n");
 837                 goto error;
 838         }
 839         dev->minor = interface->minor;
 840
 841         /* let the user know what node this device is now attached to */
 842         dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
 843                  "%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
 844                  USB_MAJOR, dev->minor);
 845
 846 exit:
 847         kfree(get_version_reply);
 848         return retval;
 849
 850 error:
 851         kfree(get_version_reply);
 852         tower_delete(dev);
 853         return retval;
 854 }
 855
 856
 857 /*
 858  *      tower_disconnect
 859  *
 860  *      Called by the usb core when the device is removed from the system.
 861  */
 862 static void tower_disconnect(struct usb_interface *interface)
 863 {
 864         struct lego_usb_tower *dev;
 865         int minor;
 866
 867         dev = usb_get_intfdata(interface);
 868
 869         minor = dev->minor;
 870
 871         /* give back our minor and prevent further open() */
 872         usb_deregister_dev(interface, &tower_class);
 873
 874         /* stop I/O */
 875         usb_poison_urb(dev->interrupt_in_urb);
 876         usb_poison_urb(dev->interrupt_out_urb);
 877
 878         mutex_lock(&dev->lock);
 879
 880         /* if the device is not opened, then we clean up right now */
 881         if (!dev->open_count) {
 882                 mutex_unlock(&dev->lock);
 883                 tower_delete(dev);
 884         } else {
 885                 dev->disconnected = 1;
 886                 /* wake up pollers */
 887                 wake_up_interruptible_all(&dev->read_wait);
 888                 wake_up_interruptible_all(&dev->write_wait);
 889                 mutex_unlock(&dev->lock);
 890         }
 891
 892         dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
 893                  (minor - LEGO_USB_TOWER_MINOR_BASE));
 894 }
 895
 896 module_usb_driver(tower_driver);
 897
 898 MODULE_AUTHOR(DRIVER_AUTHOR);
 899 MODULE_DESCRIPTION(DRIVER_DESC);
 900 MODULE_LICENSE("GPL");