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