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