drivers/media/rc/lirc_dev.c

   1 /*
   2  * LIRC base driver
   3  *
   4  * by Artur Lipowski <[email protected]>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/kernel.h>
  24 #include <linux/sched.h>
  25 #include <linux/errno.h>
  26 #include <linux/ioctl.h>
  27 #include <linux/fs.h>
  28 #include <linux/poll.h>
  29 #include <linux/completion.h>
  30 #include <linux/mutex.h>
  31 #include <linux/wait.h>
  32 #include <linux/unistd.h>
  33 #include <linux/kthread.h>
  34 #include <linux/bitops.h>
  35 #include <linux/device.h>
  36 #include <linux/cdev.h>
  37
  38 #include <media/rc-core.h>
  39 #include <media/lirc.h>
  40 #include <media/lirc_dev.h>
  41
  42 static bool debug;
  43
  44 #define IRCTL_DEV_NAME  "BaseRemoteCtl"
  45 #define NOPLUG          -1
  46 #define LOGHEAD         "lirc_dev (%s[%d]): "
  47
  48 static dev_t lirc_base_dev;
  49
  50 struct irctl {
  51         struct lirc_driver d;
  52         int attached;
  53         int open;
  54
  55         struct mutex irctl_lock;
  56         struct lirc_buffer *buf;
  57         unsigned int chunk_size;
  58
  59         struct cdev *cdev;
  60
  61         struct task_struct *task;
  62         long jiffies_to_wait;
  63 };
  64
  65 static DEFINE_MUTEX(lirc_dev_lock);
  66
  67 static struct irctl *irctls[MAX_IRCTL_DEVICES];
  68
  69 /* Only used for sysfs but defined to void otherwise */
  70 static struct class *lirc_class;
  71
  72 /*  helper function
  73  *  initializes the irctl structure
  74  */
  75 static void lirc_irctl_init(struct irctl *ir)
  76 {
  77         mutex_init(&ir->irctl_lock);
  78         ir->d.minor = NOPLUG;
  79 }
  80
  81 static void lirc_irctl_cleanup(struct irctl *ir)
  82 {
  83         dev_dbg(ir->d.dev, LOGHEAD "cleaning up\n", ir->d.name, ir->d.minor);
  84
  85         device_destroy(lirc_class, MKDEV(MAJOR(lirc_base_dev), ir->d.minor));
  86
  87         if (ir->buf != ir->d.rbuf) {
  88                 lirc_buffer_free(ir->buf);
  89                 kfree(ir->buf);
  90         }
  91         ir->buf = NULL;
  92 }
  93
  94 /*  helper function
  95  *  reads key codes from driver and puts them into buffer
  96  *  returns 0 on success
  97  */
  98 static int lirc_add_to_buf(struct irctl *ir)
  99 {
 100         if (ir->d.add_to_buf) {
 101                 int res = -ENODATA;
 102                 int got_data = 0;
 103
 104                 /*
 105                  * service the device as long as it is returning
 106                  * data and we have space
 107                  */
 108 get_data:
 109                 res = ir->d.add_to_buf(ir->d.data, ir->buf);
 110                 if (res == 0) {
 111                         got_data++;
 112                         goto get_data;
 113                 }
 114
 115                 if (res == -ENODEV)
 116                         kthread_stop(ir->task);
 117
 118                 return got_data ? 0 : res;
 119         }
 120
 121         return 0;
 122 }
 123
 124 /* main function of the polling thread
 125  */
 126 static int lirc_thread(void *irctl)
 127 {
 128         struct irctl *ir = irctl;
 129
 130         dev_dbg(ir->d.dev, LOGHEAD "poll thread started\n",
 131                 ir->d.name, ir->d.minor);
 132
 133         do {
 134                 if (ir->open) {
 135                         if (ir->jiffies_to_wait) {
 136                                 set_current_state(TASK_INTERRUPTIBLE);
 137                                 schedule_timeout(ir->jiffies_to_wait);
 138                         }
 139                         if (kthread_should_stop())
 140                                 break;
 141                         if (!lirc_add_to_buf(ir))
 142                                 wake_up_interruptible(&ir->buf->wait_poll);
 143                 } else {
 144                         set_current_state(TASK_INTERRUPTIBLE);
 145                         schedule();
 146                 }
 147         } while (!kthread_should_stop());
 148
 149         dev_dbg(ir->d.dev, LOGHEAD "poll thread ended\n",
 150                 ir->d.name, ir->d.minor);
 151
 152         return 0;
 153 }
 154
 155
 156 static const struct file_operations lirc_dev_fops = {
 157         .owner          = THIS_MODULE,
 158         .read           = lirc_dev_fop_read,
 159         .write          = lirc_dev_fop_write,
 160         .poll           = lirc_dev_fop_poll,
 161         .unlocked_ioctl = lirc_dev_fop_ioctl,
 162 #ifdef CONFIG_COMPAT
 163         .compat_ioctl   = lirc_dev_fop_ioctl,
 164 #endif
 165         .open           = lirc_dev_fop_open,
 166         .release        = lirc_dev_fop_close,
 167         .llseek         = noop_llseek,
 168 };
 169
 170 static int lirc_cdev_add(struct irctl *ir)
 171 {
 172         int retval = -ENOMEM;
 173         struct lirc_driver *d = &ir->d;
 174         struct cdev *cdev;
 175
 176         cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
 177         if (!cdev)
 178                 goto err_out;
 179
 180         if (d->fops) {
 181                 cdev_init(cdev, d->fops);
 182                 cdev->owner = d->owner;
 183         } else {
 184                 cdev_init(cdev, &lirc_dev_fops);
 185                 cdev->owner = THIS_MODULE;
 186         }
 187         retval = kobject_set_name(&cdev->kobj, "lirc%d", d->minor);
 188         if (retval)
 189                 goto err_out;
 190
 191         retval = cdev_add(cdev, MKDEV(MAJOR(lirc_base_dev), d->minor), 1);
 192         if (retval) {
 193                 kobject_put(&cdev->kobj);
 194                 goto err_out;
 195         }
 196
 197         ir->cdev = cdev;
 198
 199         return 0;
 200
 201 err_out:
 202         kfree(cdev);
 203         return retval;
 204 }
 205
 206 int lirc_register_driver(struct lirc_driver *d)
 207 {
 208         struct irctl *ir;
 209         int minor;
 210         int bytes_in_key;
 211         unsigned int chunk_size;
 212         unsigned int buffer_size;
 213         int err;
 214
 215         if (!d) {
 216                 printk(KERN_ERR "lirc_dev: lirc_register_driver: "
 217                        "driver pointer must be not NULL!\n");
 218                 err = -EBADRQC;
 219                 goto out;
 220         }
 221
 222         if (!d->dev) {
 223                 printk(KERN_ERR "%s: dev pointer not filled in!\n", __func__);
 224                 err = -EINVAL;
 225                 goto out;
 226         }
 227
 228         if (MAX_IRCTL_DEVICES <= d->minor) {
 229                 dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 230                         "\"minor\" must be between 0 and %d (%d)!\n",
 231                         MAX_IRCTL_DEVICES - 1, d->minor);
 232                 err = -EBADRQC;
 233                 goto out;
 234         }
 235
 236         if (1 > d->code_length || (BUFLEN * 8) < d->code_length) {
 237                 dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 238                         "code length in bits for minor (%d) "
 239                         "must be less than %d!\n",
 240                         d->minor, BUFLEN * 8);
 241                 err = -EBADRQC;
 242                 goto out;
 243         }
 244
 245         dev_dbg(d->dev, "lirc_dev: lirc_register_driver: sample_rate: %d\n",
 246                 d->sample_rate);
 247         if (d->sample_rate) {
 248                 if (2 > d->sample_rate || HZ < d->sample_rate) {
 249                         dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 250                                 "sample_rate must be between 2 and %d!\n", HZ);
 251                         err = -EBADRQC;
 252                         goto out;
 253                 }
 254                 if (!d->add_to_buf) {
 255                         dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 256                                 "add_to_buf cannot be NULL when "
 257                                 "sample_rate is set\n");
 258                         err = -EBADRQC;
 259                         goto out;
 260                 }
 261         } else if (!(d->fops && d->fops->read) && !d->rbuf) {
 262                 dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 263                         "fops->read and rbuf cannot all be NULL!\n");
 264                 err = -EBADRQC;
 265                 goto out;
 266         } else if (!d->rbuf) {
 267                 if (!(d->fops && d->fops->read && d->fops->poll &&
 268                       d->fops->unlocked_ioctl)) {
 269                         dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 270                                 "neither read, poll nor unlocked_ioctl can be NULL!\n");
 271                         err = -EBADRQC;
 272                         goto out;
 273                 }
 274         }
 275
 276         mutex_lock(&lirc_dev_lock);
 277
 278         minor = d->minor;
 279
 280         if (minor < 0) {
 281                 /* find first free slot for driver */
 282                 for (minor = 0; minor < MAX_IRCTL_DEVICES; minor++)
 283                         if (!irctls[minor])
 284                                 break;
 285                 if (MAX_IRCTL_DEVICES == minor) {
 286                         dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 287                                 "no free slots for drivers!\n");
 288                         err = -ENOMEM;
 289                         goto out_lock;
 290                 }
 291         } else if (irctls[minor]) {
 292                 dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 293                         "minor (%d) just registered!\n", minor);
 294                 err = -EBUSY;
 295                 goto out_lock;
 296         }
 297
 298         ir = kzalloc(sizeof(struct irctl), GFP_KERNEL);
 299         if (!ir) {
 300                 err = -ENOMEM;
 301                 goto out_lock;
 302         }
 303         lirc_irctl_init(ir);
 304         irctls[minor] = ir;
 305         d->minor = minor;
 306
 307         if (d->sample_rate) {
 308                 ir->jiffies_to_wait = HZ / d->sample_rate;
 309         } else {
 310                 /* it means - wait for external event in task queue */
 311                 ir->jiffies_to_wait = 0;
 312         }
 313
 314         /* some safety check 8-) */
 315         d->name[sizeof(d->name)-1] = '\0';
 316
 317         bytes_in_key = BITS_TO_LONGS(d->code_length) +
 318                         (d->code_length % 8 ? 1 : 0);
 319         buffer_size = d->buffer_size ? d->buffer_size : BUFLEN / bytes_in_key;
 320         chunk_size  = d->chunk_size  ? d->chunk_size  : bytes_in_key;
 321
 322         if (d->rbuf) {
 323                 ir->buf = d->rbuf;
 324         } else {
 325                 ir->buf = kmalloc(sizeof(struct lirc_buffer), GFP_KERNEL);
 326                 if (!ir->buf) {
 327                         err = -ENOMEM;
 328                         goto out_lock;
 329                 }
 330                 err = lirc_buffer_init(ir->buf, chunk_size, buffer_size);
 331                 if (err) {
 332                         kfree(ir->buf);
 333                         goto out_lock;
 334                 }
 335         }
 336         ir->chunk_size = ir->buf->chunk_size;
 337
 338         if (d->features == 0)
 339                 d->features = LIRC_CAN_REC_LIRCCODE;
 340
 341         ir->d = *d;
 342
 343         device_create(lirc_class, ir->d.dev,
 344                       MKDEV(MAJOR(lirc_base_dev), ir->d.minor), NULL,
 345                       "lirc%u", ir->d.minor);
 346
 347         if (d->sample_rate) {
 348                 /* try to fire up polling thread */
 349                 ir->task = kthread_run(lirc_thread, (void *)ir, "lirc_dev");
 350                 if (IS_ERR(ir->task)) {
 351                         dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 352                                 "cannot run poll thread for minor = %d\n",
 353                                 d->minor);
 354                         err = -ECHILD;
 355                         goto out_sysfs;
 356                 }
 357         }
 358
 359         err = lirc_cdev_add(ir);
 360         if (err)
 361                 goto out_sysfs;
 362
 363         ir->attached = 1;
 364         mutex_unlock(&lirc_dev_lock);
 365
 366         dev_info(ir->d.dev, "lirc_dev: driver %s registered at minor = %d\n",
 367                  ir->d.name, ir->d.minor);
 368         return minor;
 369
 370 out_sysfs:
 371         device_destroy(lirc_class, MKDEV(MAJOR(lirc_base_dev), ir->d.minor));
 372 out_lock:
 373         mutex_unlock(&lirc_dev_lock);
 374 out:
 375         return err;
 376 }
 377 EXPORT_SYMBOL(lirc_register_driver);
 378
 379 int lirc_unregister_driver(int minor)
 380 {
 381         struct irctl *ir;
 382         struct cdev *cdev;
 383
 384         if (minor < 0 || minor >= MAX_IRCTL_DEVICES) {
 385                 printk(KERN_ERR "lirc_dev: %s: minor (%d) must be between "
 386                        "0 and %d!\n", __func__, minor, MAX_IRCTL_DEVICES - 1);
 387                 return -EBADRQC;
 388         }
 389
 390         ir = irctls[minor];
 391         if (!ir) {
 392                 printk(KERN_ERR "lirc_dev: %s: failed to get irctl struct "
 393                        "for minor %d!\n", __func__, minor);
 394                 return -ENOENT;
 395         }
 396
 397         cdev = ir->cdev;
 398
 399         mutex_lock(&lirc_dev_lock);
 400
 401         if (ir->d.minor != minor) {
 402                 printk(KERN_ERR "lirc_dev: %s: minor (%d) device not "
 403                        "registered!\n", __func__, minor);
 404                 mutex_unlock(&lirc_dev_lock);
 405                 return -ENOENT;
 406         }
 407
 408         /* end up polling thread */
 409         if (ir->task)
 410                 kthread_stop(ir->task);
 411
 412         dev_dbg(ir->d.dev, "lirc_dev: driver %s unregistered from minor = %d\n",
 413                 ir->d.name, ir->d.minor);
 414
 415         ir->attached = 0;
 416         if (ir->open) {
 417                 dev_dbg(ir->d.dev, LOGHEAD "releasing opened driver\n",
 418                         ir->d.name, ir->d.minor);
 419                 wake_up_interruptible(&ir->buf->wait_poll);
 420                 mutex_lock(&ir->irctl_lock);
 421                 ir->d.set_use_dec(ir->d.data);
 422                 module_put(cdev->owner);
 423                 mutex_unlock(&ir->irctl_lock);
 424         } else {
 425                 lirc_irctl_cleanup(ir);
 426                 cdev_del(cdev);
 427                 kfree(cdev);
 428                 kfree(ir);
 429                 irctls[minor] = NULL;
 430         }
 431
 432         mutex_unlock(&lirc_dev_lock);
 433
 434         return 0;
 435 }
 436 EXPORT_SYMBOL(lirc_unregister_driver);
 437
 438 int lirc_dev_fop_open(struct inode *inode, struct file *file)
 439 {
 440         struct irctl *ir;
 441         struct cdev *cdev;
 442         int retval = 0;
 443
 444         if (iminor(inode) >= MAX_IRCTL_DEVICES) {
 445                 printk(KERN_WARNING "lirc_dev [%d]: open result = -ENODEV\n",
 446                        iminor(inode));
 447                 return -ENODEV;
 448         }
 449
 450         if (mutex_lock_interruptible(&lirc_dev_lock))
 451                 return -ERESTARTSYS;
 452
 453         ir = irctls[iminor(inode)];
 454         if (!ir) {
 455                 retval = -ENODEV;
 456                 goto error;
 457         }
 458
 459         dev_dbg(ir->d.dev, LOGHEAD "open called\n", ir->d.name, ir->d.minor);
 460
 461         if (ir->d.minor == NOPLUG) {
 462                 retval = -ENODEV;
 463                 goto error;
 464         }
 465
 466         if (ir->open) {
 467                 retval = -EBUSY;
 468                 goto error;
 469         }
 470
 471         if (ir->d.rdev) {
 472                 retval = rc_open(ir->d.rdev);
 473                 if (retval)
 474                         goto error;
 475         }
 476
 477         cdev = ir->cdev;
 478         if (try_module_get(cdev->owner)) {
 479                 ir->open++;
 480                 retval = ir->d.set_use_inc(ir->d.data);
 481
 482                 if (retval) {
 483                         module_put(cdev->owner);
 484                         ir->open--;
 485                 } else {
 486                         lirc_buffer_clear(ir->buf);
 487                 }
 488                 if (ir->task)
 489                         wake_up_process(ir->task);
 490         }
 491
 492 error:
 493         if (ir)
 494                 dev_dbg(ir->d.dev, LOGHEAD "open result = %d\n",
 495                         ir->d.name, ir->d.minor, retval);
 496
 497         mutex_unlock(&lirc_dev_lock);
 498
 499         nonseekable_open(inode, file);
 500
 501         return retval;
 502 }
 503 EXPORT_SYMBOL(lirc_dev_fop_open);
 504
 505 int lirc_dev_fop_close(struct inode *inode, struct file *file)
 506 {
 507         struct irctl *ir = irctls[iminor(inode)];
 508         struct cdev *cdev;
 509         int ret;
 510
 511         if (!ir) {
 512                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 513                 return -EINVAL;
 514         }
 515
 516         cdev = ir->cdev;
 517
 518         dev_dbg(ir->d.dev, LOGHEAD "close called\n", ir->d.name, ir->d.minor);
 519
 520         ret = mutex_lock_killable(&lirc_dev_lock);
 521         WARN_ON(ret);
 522
 523         rc_close(ir->d.rdev);
 524
 525         ir->open--;
 526         if (ir->attached) {
 527                 ir->d.set_use_dec(ir->d.data);
 528                 module_put(cdev->owner);
 529         } else {
 530                 lirc_irctl_cleanup(ir);
 531                 cdev_del(cdev);
 532                 irctls[ir->d.minor] = NULL;
 533                 kfree(cdev);
 534                 kfree(ir);
 535         }
 536
 537         if (!ret)
 538                 mutex_unlock(&lirc_dev_lock);
 539
 540         return 0;
 541 }
 542 EXPORT_SYMBOL(lirc_dev_fop_close);
 543
 544 unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait)
 545 {
 546         struct irctl *ir = irctls[iminor(file_inode(file))];
 547         unsigned int ret;
 548
 549         if (!ir) {
 550                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 551                 return POLLERR;
 552         }
 553
 554         dev_dbg(ir->d.dev, LOGHEAD "poll called\n", ir->d.name, ir->d.minor);
 555
 556         if (!ir->attached)
 557                 return POLLERR;
 558
 559         if (ir->buf) {
 560                 poll_wait(file, &ir->buf->wait_poll, wait);
 561
 562                 if (lirc_buffer_empty(ir->buf))
 563                         ret = 0;
 564                 else
 565                         ret = POLLIN | POLLRDNORM;
 566         } else
 567                 ret = POLLERR;
 568
 569         dev_dbg(ir->d.dev, LOGHEAD "poll result = %d\n",
 570                 ir->d.name, ir->d.minor, ret);
 571
 572         return ret;
 573 }
 574 EXPORT_SYMBOL(lirc_dev_fop_poll);
 575
 576 long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 577 {
 578         __u32 mode;
 579         int result = 0;
 580         struct irctl *ir = irctls[iminor(file_inode(file))];
 581
 582         if (!ir) {
 583                 printk(KERN_ERR "lirc_dev: %s: no irctl found!\n", __func__);
 584                 return -ENODEV;
 585         }
 586
 587         dev_dbg(ir->d.dev, LOGHEAD "ioctl called (0x%x)\n",
 588                 ir->d.name, ir->d.minor, cmd);
 589
 590         if (ir->d.minor == NOPLUG || !ir->attached) {
 591                 dev_dbg(ir->d.dev, LOGHEAD "ioctl result = -ENODEV\n",
 592                         ir->d.name, ir->d.minor);
 593                 return -ENODEV;
 594         }
 595
 596         mutex_lock(&ir->irctl_lock);
 597
 598         switch (cmd) {
 599         case LIRC_GET_FEATURES:
 600                 result = put_user(ir->d.features, (__u32 __user *)arg);
 601                 break;
 602         case LIRC_GET_REC_MODE:
 603                 if (!(ir->d.features & LIRC_CAN_REC_MASK)) {
 604                         result = -ENOSYS;
 605                         break;
 606                 }
 607
 608                 result = put_user(LIRC_REC2MODE
 609                                   (ir->d.features & LIRC_CAN_REC_MASK),
 610                                   (__u32 __user *)arg);
 611                 break;
 612         case LIRC_SET_REC_MODE:
 613                 if (!(ir->d.features & LIRC_CAN_REC_MASK)) {
 614                         result = -ENOSYS;
 615                         break;
 616                 }
 617
 618                 result = get_user(mode, (__u32 __user *)arg);
 619                 if (!result && !(LIRC_MODE2REC(mode) & ir->d.features))
 620                         result = -EINVAL;
 621                 /*
 622                  * FIXME: We should actually set the mode somehow but
 623                  * for now, lirc_serial doesn't support mode changing either
 624                  */
 625                 break;
 626         case LIRC_GET_LENGTH:
 627                 result = put_user(ir->d.code_length, (__u32 __user *)arg);
 628                 break;
 629         case LIRC_GET_MIN_TIMEOUT:
 630                 if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
 631                     ir->d.min_timeout == 0) {
 632                         result = -ENOSYS;
 633                         break;
 634                 }
 635
 636                 result = put_user(ir->d.min_timeout, (__u32 __user *)arg);
 637                 break;
 638         case LIRC_GET_MAX_TIMEOUT:
 639                 if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
 640                     ir->d.max_timeout == 0) {
 641                         result = -ENOSYS;
 642                         break;
 643                 }
 644
 645                 result = put_user(ir->d.max_timeout, (__u32 __user *)arg);
 646                 break;
 647         default:
 648                 result = -EINVAL;
 649         }
 650
 651         dev_dbg(ir->d.dev, LOGHEAD "ioctl result = %d\n",
 652                 ir->d.name, ir->d.minor, result);
 653
 654         mutex_unlock(&ir->irctl_lock);
 655
 656         return result;
 657 }
 658 EXPORT_SYMBOL(lirc_dev_fop_ioctl);
 659
 660 ssize_t lirc_dev_fop_read(struct file *file,
 661                           char __user *buffer,
 662                           size_t length,
 663                           loff_t *ppos)
 664 {
 665         struct irctl *ir = irctls[iminor(file_inode(file))];
 666         unsigned char *buf;
 667         int ret = 0, written = 0;
 668         DECLARE_WAITQUEUE(wait, current);
 669
 670         if (!ir) {
 671                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 672                 return -ENODEV;
 673         }
 674
 675         dev_dbg(ir->d.dev, LOGHEAD "read called\n", ir->d.name, ir->d.minor);
 676
 677         buf = kzalloc(ir->chunk_size, GFP_KERNEL);
 678         if (!buf)
 679                 return -ENOMEM;
 680
 681         if (mutex_lock_interruptible(&ir->irctl_lock)) {
 682                 ret = -ERESTARTSYS;
 683                 goto out_unlocked;
 684         }
 685         if (!ir->attached) {
 686                 ret = -ENODEV;
 687                 goto out_locked;
 688         }
 689
 690         if (length % ir->chunk_size) {
 691                 ret = -EINVAL;
 692                 goto out_locked;
 693         }
 694
 695         /*
 696          * we add ourselves to the task queue before buffer check
 697          * to avoid losing scan code (in case when queue is awaken somewhere
 698          * between while condition checking and scheduling)
 699          */
 700         add_wait_queue(&ir->buf->wait_poll, &wait);
 701         set_current_state(TASK_INTERRUPTIBLE);
 702
 703         /*
 704          * while we didn't provide 'length' bytes, device is opened in blocking
 705          * mode and 'copy_to_user' is happy, wait for data.
 706          */
 707         while (written < length && ret == 0) {
 708                 if (lirc_buffer_empty(ir->buf)) {
 709                         /* According to the read(2) man page, 'written' can be
 710                          * returned as less than 'length', instead of blocking
 711                          * again, returning -EWOULDBLOCK, or returning
 712                          * -ERESTARTSYS */
 713                         if (written)
 714                                 break;
 715                         if (file->f_flags & O_NONBLOCK) {
 716                                 ret = -EWOULDBLOCK;
 717                                 break;
 718                         }
 719                         if (signal_pending(current)) {
 720                                 ret = -ERESTARTSYS;
 721                                 break;
 722                         }
 723
 724                         mutex_unlock(&ir->irctl_lock);
 725                         schedule();
 726                         set_current_state(TASK_INTERRUPTIBLE);
 727
 728                         if (mutex_lock_interruptible(&ir->irctl_lock)) {
 729                                 ret = -ERESTARTSYS;
 730                                 remove_wait_queue(&ir->buf->wait_poll, &wait);
 731                                 set_current_state(TASK_RUNNING);
 732                                 goto out_unlocked;
 733                         }
 734
 735                         if (!ir->attached) {
 736                                 ret = -ENODEV;
 737                                 break;
 738                         }
 739                 } else {
 740                         lirc_buffer_read(ir->buf, buf);
 741                         ret = copy_to_user((void __user *)buffer+written, buf,
 742                                            ir->buf->chunk_size);
 743                         if (!ret)
 744                                 written += ir->buf->chunk_size;
 745                         else
 746                                 ret = -EFAULT;
 747                 }
 748         }
 749
 750         remove_wait_queue(&ir->buf->wait_poll, &wait);
 751         set_current_state(TASK_RUNNING);
 752
 753 out_locked:
 754         mutex_unlock(&ir->irctl_lock);
 755
 756 out_unlocked:
 757         kfree(buf);
 758         dev_dbg(ir->d.dev, LOGHEAD "read result = %s (%d)\n",
 759                 ir->d.name, ir->d.minor, ret ? "<fail>" : "<ok>", ret);
 760
 761         return ret ? ret : written;
 762 }
 763 EXPORT_SYMBOL(lirc_dev_fop_read);
 764
 765 void *lirc_get_pdata(struct file *file)
 766 {
 767         return irctls[iminor(file_inode(file))]->d.data;
 768 }
 769 EXPORT_SYMBOL(lirc_get_pdata);
 770
 771
 772 ssize_t lirc_dev_fop_write(struct file *file, const char __user *buffer,
 773                            size_t length, loff_t *ppos)
 774 {
 775         struct irctl *ir = irctls[iminor(file_inode(file))];
 776
 777         if (!ir) {
 778                 printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 779                 return -ENODEV;
 780         }
 781
 782         dev_dbg(ir->d.dev, LOGHEAD "write called\n", ir->d.name, ir->d.minor);
 783
 784         if (!ir->attached)
 785                 return -ENODEV;
 786
 787         return -EINVAL;
 788 }
 789 EXPORT_SYMBOL(lirc_dev_fop_write);
 790
 791
 792 static int __init lirc_dev_init(void)
 793 {
 794         int retval;
 795
 796         lirc_class = class_create(THIS_MODULE, "lirc");
 797         if (IS_ERR(lirc_class)) {
 798                 retval = PTR_ERR(lirc_class);
 799                 printk(KERN_ERR "lirc_dev: class_create failed\n");
 800                 goto error;
 801         }
 802
 803         retval = alloc_chrdev_region(&lirc_base_dev, 0, MAX_IRCTL_DEVICES,
 804                                      IRCTL_DEV_NAME);
 805         if (retval) {
 806                 class_destroy(lirc_class);
 807                 printk(KERN_ERR "lirc_dev: alloc_chrdev_region failed\n");
 808                 goto error;
 809         }
 810
 811
 812         printk(KERN_INFO "lirc_dev: IR Remote Control driver registered, "
 813                "major %d \n", MAJOR(lirc_base_dev));
 814
 815 error:
 816         return retval;
 817 }
 818
 819
 820
 821 static void __exit lirc_dev_exit(void)
 822 {
 823         class_destroy(lirc_class);
 824         unregister_chrdev_region(lirc_base_dev, MAX_IRCTL_DEVICES);
 825         printk(KERN_INFO "lirc_dev: module unloaded\n");
 826 }
 827
 828 module_init(lirc_dev_init);
 829 module_exit(lirc_dev_exit);
 830
 831 MODULE_DESCRIPTION("LIRC base driver module");
 832 MODULE_AUTHOR("Artur Lipowski");
 833 MODULE_LICENSE("GPL");
 834
 835 module_param(debug, bool, S_IRUGO | S_IWUSR);
 836 MODULE_PARM_DESC(debug, "Enable debugging messages");