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         nonseekable_open(inode, file);
 315         subminor = iminor(inode);
 316
 317         interface = usb_find_interface(&tower_driver, subminor);
 318         if (!interface) {
 319                 pr_err("error, can't find device for minor %d\n", subminor);
 320                 retval = -ENODEV;
 321                 goto exit;
 322         }
 323
 324         dev = usb_get_intfdata(interface);
 325         if (!dev) {
 326                 retval = -ENODEV;
 327                 goto exit;
 328         }
 329
 330         /* lock this device */
 331         if (mutex_lock_interruptible(&dev->lock)) {
 332                 retval = -ERESTARTSYS;
 333                 goto exit;
 334         }
 335
 336
 337         /* allow opening only once */
 338         if (dev->open_count) {
 339                 retval = -EBUSY;
 340                 goto unlock_exit;
 341         }
 342
 343         /* reset the tower */
 344         result = usb_control_msg_recv(dev->udev, 0,
 345                                       LEGO_USB_TOWER_REQUEST_RESET,
 346                                       USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 347                                       0, 0,
 348                                       &reset_reply, sizeof(reset_reply), 1000,
 349                                       GFP_KERNEL);
 350         if (result < 0) {
 351                 dev_err(&dev->udev->dev,
 352                         "LEGO USB Tower reset control request failed\n");
 353                 retval = result;
 354                 goto unlock_exit;
 355         }
 356
 357         /* initialize in direction */
 358         dev->read_buffer_length = 0;
 359         dev->read_packet_length = 0;
 360         usb_fill_int_urb(dev->interrupt_in_urb,
 361                          dev->udev,
 362                          usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
 363                          dev->interrupt_in_buffer,
 364                          usb_endpoint_maxp(dev->interrupt_in_endpoint),
 365                          tower_interrupt_in_callback,
 366                          dev,
 367                          dev->interrupt_in_interval);
 368
 369         dev->interrupt_in_done = 0;
 370         mb();
 371
 372         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
 373         if (retval) {
 374                 dev_err(&dev->udev->dev,
 375                         "Couldn't submit interrupt_in_urb %d\n", retval);
 376                 goto unlock_exit;
 377         }
 378
 379         /* save device in the file's private structure */
 380         file->private_data = dev;
 381
 382         dev->open_count = 1;
 383
 384 unlock_exit:
 385         mutex_unlock(&dev->lock);
 386
 387 exit:
 388         return retval;
 389 }
 390
 391 /*
 392  *      tower_release
 393  */
 394 static int tower_release(struct inode *inode, struct file *file)
 395 {
 396         struct lego_usb_tower *dev;
 397         int retval = 0;
 398
 399         dev = file->private_data;
 400         if (dev == NULL) {
 401                 retval = -ENODEV;
 402                 goto exit;
 403         }
 404
 405         mutex_lock(&dev->lock);
 406
 407         if (dev->disconnected) {
 408                 /* the device was unplugged before the file was released */
 409
 410                 /* unlock here as tower_delete frees dev */
 411                 mutex_unlock(&dev->lock);
 412                 tower_delete(dev);
 413                 goto exit;
 414         }
 415
 416         /* wait until write transfer is finished */
 417         if (dev->interrupt_out_busy) {
 418                 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy,
 419                                                  2 * HZ);
 420         }
 421
 422         /* shutdown transfers */
 423         usb_kill_urb(dev->interrupt_in_urb);
 424         usb_kill_urb(dev->interrupt_out_urb);
 425
 426         dev->open_count = 0;
 427
 428         mutex_unlock(&dev->lock);
 429 exit:
 430         return retval;
 431 }
 432
 433 /*
 434  *      tower_check_for_read_packet
 435  *
 436  *      To get correct semantics for signals and non-blocking I/O
 437  *      with packetizing we pretend not to see any data in the read buffer
 438  *      until it has been there unchanged for at least
 439  *      dev->packet_timeout_jiffies, or until the buffer is full.
 440  */
 441 static void tower_check_for_read_packet(struct lego_usb_tower *dev)
 442 {
 443         spin_lock_irq(&dev->read_buffer_lock);
 444         if (!packet_timeout
 445             || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
 446             || dev->read_buffer_length == read_buffer_size) {
 447                 dev->read_packet_length = dev->read_buffer_length;
 448         }
 449         dev->interrupt_in_done = 0;
 450         spin_unlock_irq(&dev->read_buffer_lock);
 451 }
 452
 453
 454 /*
 455  *      tower_poll
 456  */
 457 static __poll_t tower_poll(struct file *file, poll_table *wait)
 458 {
 459         struct lego_usb_tower *dev;
 460         __poll_t mask = 0;
 461
 462         dev = file->private_data;
 463
 464         if (dev->disconnected)
 465                 return EPOLLERR | EPOLLHUP;
 466
 467         poll_wait(file, &dev->read_wait, wait);
 468         poll_wait(file, &dev->write_wait, wait);
 469
 470         tower_check_for_read_packet(dev);
 471         if (dev->read_packet_length > 0)
 472                 mask |= EPOLLIN | EPOLLRDNORM;
 473         if (!dev->interrupt_out_busy)
 474                 mask |= EPOLLOUT | EPOLLWRNORM;
 475
 476         return mask;
 477 }
 478
 479
 480 /*
 481  *      tower_llseek
 482  */
 483 static loff_t tower_llseek(struct file *file, loff_t off, int whence)
 484 {
 485         return -ESPIPE;         /* unseekable */
 486 }
 487
 488
 489 /*
 490  *      tower_read
 491  */
 492 static ssize_t tower_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 493 {
 494         struct lego_usb_tower *dev;
 495         size_t bytes_to_read;
 496         int i;
 497         int retval = 0;
 498         unsigned long timeout = 0;
 499
 500         dev = file->private_data;
 501
 502         /* lock this object */
 503         if (mutex_lock_interruptible(&dev->lock)) {
 504                 retval = -ERESTARTSYS;
 505                 goto exit;
 506         }
 507
 508         /* verify that the device wasn't unplugged */
 509         if (dev->disconnected) {
 510                 retval = -ENODEV;
 511                 goto unlock_exit;
 512         }
 513
 514         /* verify that we actually have some data to read */
 515         if (count == 0) {
 516                 dev_dbg(&dev->udev->dev, "read request of 0 bytes\n");
 517                 goto unlock_exit;
 518         }
 519
 520         if (read_timeout)
 521                 timeout = jiffies + msecs_to_jiffies(read_timeout);
 522
 523         /* wait for data */
 524         tower_check_for_read_packet(dev);
 525         while (dev->read_packet_length == 0) {
 526                 if (file->f_flags & O_NONBLOCK) {
 527                         retval = -EAGAIN;
 528                         goto unlock_exit;
 529                 }
 530                 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
 531                 if (retval < 0)
 532                         goto unlock_exit;
 533
 534                 /* reset read timeout during read or write activity */
 535                 if (read_timeout
 536                     && (dev->read_buffer_length || dev->interrupt_out_busy)) {
 537                         timeout = jiffies + msecs_to_jiffies(read_timeout);
 538                 }
 539                 /* check for read timeout */
 540                 if (read_timeout && time_after(jiffies, timeout)) {
 541                         retval = -ETIMEDOUT;
 542                         goto unlock_exit;
 543                 }
 544                 tower_check_for_read_packet(dev);
 545         }
 546
 547         /* copy the data from read_buffer into userspace */
 548         bytes_to_read = min(count, dev->read_packet_length);
 549
 550         if (copy_to_user(buffer, dev->read_buffer, bytes_to_read)) {
 551                 retval = -EFAULT;
 552                 goto unlock_exit;
 553         }
 554
 555         spin_lock_irq(&dev->read_buffer_lock);
 556         dev->read_buffer_length -= bytes_to_read;
 557         dev->read_packet_length -= bytes_to_read;
 558         for (i = 0; i < dev->read_buffer_length; i++)
 559                 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
 560         spin_unlock_irq(&dev->read_buffer_lock);
 561
 562         retval = bytes_to_read;
 563
 564 unlock_exit:
 565         /* unlock the device */
 566         mutex_unlock(&dev->lock);
 567
 568 exit:
 569         return retval;
 570 }
 571
 572
 573 /*
 574  *      tower_write
 575  */
 576 static ssize_t tower_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 577 {
 578         struct lego_usb_tower *dev;
 579         size_t bytes_to_write;
 580         int retval = 0;
 581
 582         dev = file->private_data;
 583
 584         /* lock this object */
 585         if (mutex_lock_interruptible(&dev->lock)) {
 586                 retval = -ERESTARTSYS;
 587                 goto exit;
 588         }
 589
 590         /* verify that the device wasn't unplugged */
 591         if (dev->disconnected) {
 592                 retval = -ENODEV;
 593                 goto unlock_exit;
 594         }
 595
 596         /* verify that we actually have some data to write */
 597         if (count == 0) {
 598                 dev_dbg(&dev->udev->dev, "write request of 0 bytes\n");
 599                 goto unlock_exit;
 600         }
 601
 602         /* wait until previous transfer is finished */
 603         while (dev->interrupt_out_busy) {
 604                 if (file->f_flags & O_NONBLOCK) {
 605                         retval = -EAGAIN;
 606                         goto unlock_exit;
 607                 }
 608                 retval = wait_event_interruptible(dev->write_wait,
 609                                                   !dev->interrupt_out_busy);
 610                 if (retval)
 611                         goto unlock_exit;
 612         }
 613
 614         /* write the data into interrupt_out_buffer from userspace */
 615         bytes_to_write = min_t(int, count, write_buffer_size);
 616         dev_dbg(&dev->udev->dev, "%s: count = %zd, bytes_to_write = %zd\n",
 617                 __func__, count, bytes_to_write);
 618
 619         if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
 620                 retval = -EFAULT;
 621                 goto unlock_exit;
 622         }
 623
 624         /* send off the urb */
 625         usb_fill_int_urb(dev->interrupt_out_urb,
 626                          dev->udev,
 627                          usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
 628                          dev->interrupt_out_buffer,
 629                          bytes_to_write,
 630                          tower_interrupt_out_callback,
 631                          dev,
 632                          dev->interrupt_out_interval);
 633
 634         dev->interrupt_out_busy = 1;
 635         wmb();
 636
 637         retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
 638         if (retval) {
 639                 dev->interrupt_out_busy = 0;
 640                 dev_err(&dev->udev->dev,
 641                         "Couldn't submit interrupt_out_urb %d\n", retval);
 642                 goto unlock_exit;
 643         }
 644         retval = bytes_to_write;
 645
 646 unlock_exit:
 647         /* unlock the device */
 648         mutex_unlock(&dev->lock);
 649
 650 exit:
 651         return retval;
 652 }
 653
 654
 655 /*
 656  *      tower_interrupt_in_callback
 657  */
 658 static void tower_interrupt_in_callback(struct urb *urb)
 659 {
 660         struct lego_usb_tower *dev = urb->context;
 661         int status = urb->status;
 662         int retval;
 663         unsigned long flags;
 664
 665         lego_usb_tower_debug_data(&dev->udev->dev, __func__,
 666                                   urb->actual_length, urb->transfer_buffer);
 667
 668         if (status) {
 669                 if (status == -ENOENT ||
 670                     status == -ECONNRESET ||
 671                     status == -ESHUTDOWN) {
 672                         goto exit;
 673                 } else {
 674                         dev_dbg(&dev->udev->dev,
 675                                 "%s: nonzero status received: %d\n", __func__,
 676                                 status);
 677                         goto resubmit; /* maybe we can recover */
 678                 }
 679         }
 680
 681         if (urb->actual_length > 0) {
 682                 spin_lock_irqsave(&dev->read_buffer_lock, flags);
 683                 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
 684                         memcpy(dev->read_buffer + dev->read_buffer_length,
 685                                dev->interrupt_in_buffer,
 686                                urb->actual_length);
 687                         dev->read_buffer_length += urb->actual_length;
 688                         dev->read_last_arrival = jiffies;
 689                         dev_dbg(&dev->udev->dev, "%s: received %d bytes\n",
 690                                 __func__, urb->actual_length);
 691                 } else {
 692                         pr_warn("read_buffer overflow, %d bytes dropped\n",
 693                                 urb->actual_length);
 694                 }
 695                 spin_unlock_irqrestore(&dev->read_buffer_lock, flags);
 696         }
 697
 698 resubmit:
 699         retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
 700         if (retval) {
 701                 dev_err(&dev->udev->dev, "%s: usb_submit_urb failed (%d)\n",
 702                         __func__, retval);
 703         }
 704 exit:
 705         dev->interrupt_in_done = 1;
 706         wake_up_interruptible(&dev->read_wait);
 707 }
 708
 709
 710 /*
 711  *      tower_interrupt_out_callback
 712  */
 713 static void tower_interrupt_out_callback(struct urb *urb)
 714 {
 715         struct lego_usb_tower *dev = urb->context;
 716         int status = urb->status;
 717
 718         lego_usb_tower_debug_data(&dev->udev->dev, __func__,
 719                                   urb->actual_length, urb->transfer_buffer);
 720
 721         /* sync/async unlink faults aren't errors */
 722         if (status && !(status == -ENOENT ||
 723                         status == -ECONNRESET ||
 724                         status == -ESHUTDOWN)) {
 725                 dev_dbg(&dev->udev->dev,
 726                         "%s: nonzero write bulk status received: %d\n", __func__,
 727                         status);
 728         }
 729
 730         dev->interrupt_out_busy = 0;
 731         wake_up_interruptible(&dev->write_wait);
 732 }
 733
 734
 735 /*
 736  *      tower_probe
 737  *
 738  *      Called by the usb core when a new device is connected that it thinks
 739  *      this driver might be interested in.
 740  */
 741 static int tower_probe(struct usb_interface *interface, const struct usb_device_id *id)
 742 {
 743         struct device *idev = &interface->dev;
 744         struct usb_device *udev = interface_to_usbdev(interface);
 745         struct lego_usb_tower *dev;
 746         struct tower_get_version_reply get_version_reply;
 747         int retval = -ENOMEM;
 748         int result;
 749
 750         /* allocate memory for our device state and initialize it */
 751         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 752         if (!dev)
 753                 goto exit;
 754
 755         mutex_init(&dev->lock);
 756         dev->udev = usb_get_dev(udev);
 757         spin_lock_init(&dev->read_buffer_lock);
 758         dev->packet_timeout_jiffies = msecs_to_jiffies(packet_timeout);
 759         dev->read_last_arrival = jiffies;
 760         init_waitqueue_head(&dev->read_wait);
 761         init_waitqueue_head(&dev->write_wait);
 762
 763         result = usb_find_common_endpoints_reverse(interface->cur_altsetting,
 764                         NULL, NULL,
 765                         &dev->interrupt_in_endpoint,
 766                         &dev->interrupt_out_endpoint);
 767         if (result) {
 768                 dev_err(idev, "interrupt endpoints not found\n");
 769                 retval = result;
 770                 goto error;
 771         }
 772
 773         dev->read_buffer = kmalloc(read_buffer_size, GFP_KERNEL);
 774         if (!dev->read_buffer)
 775                 goto error;
 776         dev->interrupt_in_buffer = kmalloc(usb_endpoint_maxp(dev->interrupt_in_endpoint), GFP_KERNEL);
 777         if (!dev->interrupt_in_buffer)
 778                 goto error;
 779         dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
 780         if (!dev->interrupt_in_urb)
 781                 goto error;
 782         dev->interrupt_out_buffer = kmalloc(write_buffer_size, GFP_KERNEL);
 783         if (!dev->interrupt_out_buffer)
 784                 goto error;
 785         dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
 786         if (!dev->interrupt_out_urb)
 787                 goto error;
 788         dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
 789         dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
 790
 791         /* get the firmware version and log it */
 792         result = usb_control_msg_recv(udev, 0,
 793                                       LEGO_USB_TOWER_REQUEST_GET_VERSION,
 794                                       USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
 795                                       0,
 796                                       0,
 797                                       &get_version_reply,
 798                                       sizeof(get_version_reply),
 799                                       1000, GFP_KERNEL);
 800         if (result) {
 801                 dev_err(idev, "get version request failed: %d\n", result);
 802                 retval = result;
 803                 goto error;
 804         }
 805         dev_info(&interface->dev,
 806                  "LEGO USB Tower firmware version is %d.%d build %d\n",
 807                  get_version_reply.major,
 808                  get_version_reply.minor,
 809                  le16_to_cpu(get_version_reply.build_no));
 810
 811         /* we can register the device now, as it is ready */
 812         usb_set_intfdata(interface, dev);
 813
 814         retval = usb_register_dev(interface, &tower_class);
 815         if (retval) {
 816                 /* something prevented us from registering this driver */
 817                 dev_err(idev, "Not able to get a minor for this device.\n");
 818                 goto error;
 819         }
 820         dev->minor = interface->minor;
 821
 822         /* let the user know what node this device is now attached to */
 823         dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
 824                  "%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
 825                  USB_MAJOR, dev->minor);
 826
 827 exit:
 828         return retval;
 829
 830 error:
 831         tower_delete(dev);
 832         return retval;
 833 }
 834
 835
 836 /*
 837  *      tower_disconnect
 838  *
 839  *      Called by the usb core when the device is removed from the system.
 840  */
 841 static void tower_disconnect(struct usb_interface *interface)
 842 {
 843         struct lego_usb_tower *dev;
 844         int minor;
 845
 846         dev = usb_get_intfdata(interface);
 847
 848         minor = dev->minor;
 849
 850         /* give back our minor and prevent further open() */
 851         usb_deregister_dev(interface, &tower_class);
 852
 853         /* stop I/O */
 854         usb_poison_urb(dev->interrupt_in_urb);
 855         usb_poison_urb(dev->interrupt_out_urb);
 856
 857         mutex_lock(&dev->lock);
 858
 859         /* if the device is not opened, then we clean up right now */
 860         if (!dev->open_count) {
 861                 mutex_unlock(&dev->lock);
 862                 tower_delete(dev);
 863         } else {
 864                 dev->disconnected = 1;
 865                 /* wake up pollers */
 866                 wake_up_interruptible_all(&dev->read_wait);
 867                 wake_up_interruptible_all(&dev->write_wait);
 868                 mutex_unlock(&dev->lock);
 869         }
 870
 871         dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
 872                  (minor - LEGO_USB_TOWER_MINOR_BASE));
 873 }
 874
 875 module_usb_driver(tower_driver);
 876
 877 MODULE_AUTHOR(DRIVER_AUTHOR);
 878 MODULE_DESCRIPTION(DRIVER_DESC);
 879 MODULE_LICENSE("GPL");