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