drivers/rtc/rtc-dev.c

   1 /*
   2  * RTC subsystem, dev interface
   3  *
   4  * Copyright (C) 2005 Tower Technologies
   5  * Author: Alessandro Zummo <a.zummo@towertech.it>
   6  *
   7  * based on arch/arm/common/rtctime.c
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12 */
  13
  14 #include <linux/module.h>
  15 #include <linux/rtc.h>
  16 #include "rtc-core.h"
  17
  18 static dev_t rtc_devt;
  19
  20 #define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
  21
  22 static int rtc_dev_open(struct inode *inode, struct file *file)
  23 {
  24         int err;
  25         struct rtc_device *rtc = container_of(inode->i_cdev,
  26                                         struct rtc_device, char_dev);
  27         const struct rtc_class_ops *ops = rtc->ops;
  28
  29         if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
  30                 return -EBUSY;
  31
  32         file->private_data = rtc;
  33
  34         err = ops->open ? ops->open(rtc->dev.parent) : 0;
  35         if (err == 0) {
  36                 spin_lock_irq(&rtc->irq_lock);
  37                 rtc->irq_data = 0;
  38                 spin_unlock_irq(&rtc->irq_lock);
  39
  40                 return 0;
  41         }
  42
  43         /* something has gone wrong */
  44         clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
  45         return err;
  46 }
  47
  48 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
  49 /*
  50  * Routine to poll RTC seconds field for change as often as possible,
  51  * after first RTC_UIE use timer to reduce polling
  52  */
  53 static void rtc_uie_task(struct work_struct *work)
  54 {
  55         struct rtc_device *rtc =
  56                 container_of(work, struct rtc_device, uie_task);
  57         struct rtc_time tm;
  58         int num = 0;
  59         int err;
  60
  61         err = rtc_read_time(rtc, &tm);
  62
  63         local_irq_disable();
  64         spin_lock(&rtc->irq_lock);
  65         if (rtc->stop_uie_polling || err) {
  66                 rtc->uie_task_active = 0;
  67         } else if (rtc->oldsecs != tm.tm_sec) {
  68                 num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
  69                 rtc->oldsecs = tm.tm_sec;
  70                 rtc->uie_timer.expires = jiffies + HZ - (HZ/10);
  71                 rtc->uie_timer_active = 1;
  72                 rtc->uie_task_active = 0;
  73                 add_timer(&rtc->uie_timer);
  74         } else if (schedule_work(&rtc->uie_task) == 0) {
  75                 rtc->uie_task_active = 0;
  76         }
  77         spin_unlock(&rtc->irq_lock);
  78         if (num)
  79                 rtc_update_irq(rtc, num, RTC_UF | RTC_IRQF);
  80         local_irq_enable();
  81 }
  82 static void rtc_uie_timer(unsigned long data)
  83 {
  84         struct rtc_device *rtc = (struct rtc_device *)data;
  85         unsigned long flags;
  86
  87         spin_lock_irqsave(&rtc->irq_lock, flags);
  88         rtc->uie_timer_active = 0;
  89         rtc->uie_task_active = 1;
  90         if ((schedule_work(&rtc->uie_task) == 0))
  91                 rtc->uie_task_active = 0;
  92         spin_unlock_irqrestore(&rtc->irq_lock, flags);
  93 }
  94
  95 static void clear_uie(struct rtc_device *rtc)
  96 {
  97         spin_lock_irq(&rtc->irq_lock);
  98         if (rtc->irq_active) {
  99                 rtc->stop_uie_polling = 1;
 100                 if (rtc->uie_timer_active) {
 101                         spin_unlock_irq(&rtc->irq_lock);
 102                         del_timer_sync(&rtc->uie_timer);
 103                         spin_lock_irq(&rtc->irq_lock);
 104                         rtc->uie_timer_active = 0;
 105                 }
 106                 if (rtc->uie_task_active) {
 107                         spin_unlock_irq(&rtc->irq_lock);
 108                         flush_scheduled_work();
 109                         spin_lock_irq(&rtc->irq_lock);
 110                 }
 111                 rtc->irq_active = 0;
 112         }
 113         spin_unlock_irq(&rtc->irq_lock);
 114 }
 115
 116 static int set_uie(struct rtc_device *rtc)
 117 {
 118         struct rtc_time tm;
 119         int err;
 120
 121         err = rtc_read_time(rtc, &tm);
 122         if (err)
 123                 return err;
 124         spin_lock_irq(&rtc->irq_lock);
 125         if (!rtc->irq_active) {
 126                 rtc->irq_active = 1;
 127                 rtc->stop_uie_polling = 0;
 128                 rtc->oldsecs = tm.tm_sec;
 129                 rtc->uie_task_active = 1;
 130                 if (schedule_work(&rtc->uie_task) == 0)
 131                         rtc->uie_task_active = 0;
 132         }
 133         rtc->irq_data = 0;
 134         spin_unlock_irq(&rtc->irq_lock);
 135         return 0;
 136 }
 137 #endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
 138
 139 static ssize_t
 140 rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 141 {
 142         struct rtc_device *rtc = file->private_data;
 143
 144         DECLARE_WAITQUEUE(wait, current);
 145         unsigned long data;
 146         ssize_t ret;
 147
 148         if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
 149                 return -EINVAL;
 150
 151         add_wait_queue(&rtc->irq_queue, &wait);
 152         do {
 153                 __set_current_state(TASK_INTERRUPTIBLE);
 154
 155                 spin_lock_irq(&rtc->irq_lock);
 156                 data = rtc->irq_data;
 157                 rtc->irq_data = 0;
 158                 spin_unlock_irq(&rtc->irq_lock);
 159
 160                 if (data != 0) {
 161                         ret = 0;
 162                         break;
 163                 }
 164                 if (file->f_flags & O_NONBLOCK) {
 165                         ret = -EAGAIN;
 166                         break;
 167                 }
 168                 if (signal_pending(current)) {
 169                         ret = -ERESTARTSYS;
 170                         break;
 171                 }
 172                 schedule();
 173         } while (1);
 174         set_current_state(TASK_RUNNING);
 175         remove_wait_queue(&rtc->irq_queue, &wait);
 176
 177         if (ret == 0) {
 178                 /* Check for any data updates */
 179                 if (rtc->ops->read_callback)
 180                         data = rtc->ops->read_callback(rtc->dev.parent,
 181                                                        data);
 182
 183                 if (sizeof(int) != sizeof(long) &&
 184                     count == sizeof(unsigned int))
 185                         ret = put_user(data, (unsigned int __user *)buf) ?:
 186                                 sizeof(unsigned int);
 187                 else
 188                         ret = put_user(data, (unsigned long __user *)buf) ?:
 189                                 sizeof(unsigned long);
 190         }
 191         return ret;
 192 }
 193
 194 static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
 195 {
 196         struct rtc_device *rtc = file->private_data;
 197         unsigned long data;
 198
 199         poll_wait(file, &rtc->irq_queue, wait);
 200
 201         data = rtc->irq_data;
 202
 203         return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
 204 }
 205
 206 static int rtc_dev_ioctl(struct inode *inode, struct file *file,
 207                 unsigned int cmd, unsigned long arg)
 208 {
 209         int err = 0;
 210         struct rtc_device *rtc = file->private_data;
 211         const struct rtc_class_ops *ops = rtc->ops;
 212         struct rtc_time tm;
 213         struct rtc_wkalrm alarm;
 214         void __user *uarg = (void __user *) arg;
 215
 216         /* check that the calling task has appropriate permissions
 217          * for certain ioctls. doing this check here is useful
 218          * to avoid duplicate code in each driver.
 219          */
 220         switch (cmd) {
 221         case RTC_EPOCH_SET:
 222         case RTC_SET_TIME:
 223                 if (!capable(CAP_SYS_TIME))
 224                         return -EACCES;
 225                 break;
 226
 227         case RTC_IRQP_SET:
 228                 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
 229                         return -EACCES;
 230                 break;
 231
 232         case RTC_PIE_ON:
 233                 if (rtc->irq_freq > rtc->max_user_freq &&
 234                                 !capable(CAP_SYS_RESOURCE))
 235                         return -EACCES;
 236                 break;
 237         }
 238
 239         /* try the driver's ioctl interface */
 240         if (ops->ioctl) {
 241                 err = ops->ioctl(rtc->dev.parent, cmd, arg);
 242                 if (err != -ENOIOCTLCMD)
 243                         return err;
 244         }
 245
 246         /* if the driver does not provide the ioctl interface
 247          * or if that particular ioctl was not implemented
 248          * (-ENOIOCTLCMD), we will try to emulate here.
 249          *
 250          * Drivers *SHOULD NOT* provide ioctl implementations
 251          * for these requests.  Instead, provide methods to
 252          * support the following code, so that the RTC's main
 253          * features are accessible without using ioctls.
 254          *
 255          * RTC and alarm times will be in UTC, by preference,
 256          * but dual-booting with MS-Windows implies RTCs must
 257          * use the local wall clock time.
 258          */
 259
 260         switch (cmd) {
 261         case RTC_ALM_READ:
 262                 err = rtc_read_alarm(rtc, &alarm);
 263                 if (err < 0)
 264                         return err;
 265
 266                 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
 267                         return -EFAULT;
 268                 break;
 269
 270         case RTC_ALM_SET:
 271                 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
 272                         return -EFAULT;
 273
 274                 alarm.enabled = 0;
 275                 alarm.pending = 0;
 276                 alarm.time.tm_wday = -1;
 277                 alarm.time.tm_yday = -1;
 278                 alarm.time.tm_isdst = -1;
 279
 280                 /* RTC_ALM_SET alarms may be up to 24 hours in the future.
 281                  * Rather than expecting every RTC to implement "don't care"
 282                  * for day/month/year fields, just force the alarm to have
 283                  * the right values for those fields.
 284                  *
 285                  * RTC_WKALM_SET should be used instead.  Not only does it
 286                  * eliminate the need for a separate RTC_AIE_ON call, it
 287                  * doesn't have the "alarm 23:59:59 in the future" race.
 288                  *
 289                  * NOTE:  some legacy code may have used invalid fields as
 290                  * wildcards, exposing hardware "periodic alarm" capabilities.
 291                  * Not supported here.
 292                  */
 293                 {
 294                         unsigned long now, then;
 295
 296                         err = rtc_read_time(rtc, &tm);
 297                         if (err < 0)
 298                                 return err;
 299                         rtc_tm_to_time(&tm, &now);
 300
 301                         alarm.time.tm_mday = tm.tm_mday;
 302                         alarm.time.tm_mon = tm.tm_mon;
 303                         alarm.time.tm_year = tm.tm_year;
 304                         err  = rtc_valid_tm(&alarm.time);
 305                         if (err < 0)
 306                                 return err;
 307                         rtc_tm_to_time(&alarm.time, &then);
 308
 309                         /* alarm may need to wrap into tomorrow */
 310                         if (then < now) {
 311                                 rtc_time_to_tm(now + 24 * 60 * 60, &tm);
 312                                 alarm.time.tm_mday = tm.tm_mday;
 313                                 alarm.time.tm_mon = tm.tm_mon;
 314                                 alarm.time.tm_year = tm.tm_year;
 315                         }
 316                 }
 317
 318                 err = rtc_set_alarm(rtc, &alarm);
 319                 break;
 320
 321         case RTC_RD_TIME:
 322                 err = rtc_read_time(rtc, &tm);
 323                 if (err < 0)
 324                         return err;
 325
 326                 if (copy_to_user(uarg, &tm, sizeof(tm)))
 327                         return -EFAULT;
 328                 break;
 329
 330         case RTC_SET_TIME:
 331                 if (copy_from_user(&tm, uarg, sizeof(tm)))
 332                         return -EFAULT;
 333
 334                 err = rtc_set_time(rtc, &tm);
 335                 break;
 336
 337         case RTC_PIE_ON:
 338                 err = rtc_irq_set_state(rtc, NULL, 1);
 339                 break;
 340
 341         case RTC_PIE_OFF:
 342                 err = rtc_irq_set_state(rtc, NULL, 0);
 343                 break;
 344
 345         case RTC_IRQP_SET:
 346                 err = rtc_irq_set_freq(rtc, NULL, arg);
 347                 break;
 348
 349         case RTC_IRQP_READ:
 350                 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
 351                 break;
 352
 353 #if 0
 354         case RTC_EPOCH_SET:
 355 #ifndef rtc_epoch
 356                 /*
 357                  * There were no RTC clocks before 1900.
 358                  */
 359                 if (arg < 1900) {
 360                         err = -EINVAL;
 361                         break;
 362                 }
 363                 rtc_epoch = arg;
 364                 err = 0;
 365 #endif
 366                 break;
 367
 368         case RTC_EPOCH_READ:
 369                 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
 370                 break;
 371 #endif
 372         case RTC_WKALM_SET:
 373                 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
 374                         return -EFAULT;
 375
 376                 err = rtc_set_alarm(rtc, &alarm);
 377                 break;
 378
 379         case RTC_WKALM_RD:
 380                 err = rtc_read_alarm(rtc, &alarm);
 381                 if (err < 0)
 382                         return err;
 383
 384                 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
 385                         return -EFAULT;
 386                 break;
 387
 388 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
 389         case RTC_UIE_OFF:
 390                 clear_uie(rtc);
 391                 return 0;
 392
 393         case RTC_UIE_ON:
 394                 return set_uie(rtc);
 395 #endif
 396         default:
 397                 err = -ENOTTY;
 398                 break;
 399         }
 400
 401         return err;
 402 }
 403
 404 static int rtc_dev_release(struct inode *inode, struct file *file)
 405 {
 406         struct rtc_device *rtc = file->private_data;
 407
 408 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
 409         clear_uie(rtc);
 410 #endif
 411         if (rtc->ops->release)
 412                 rtc->ops->release(rtc->dev.parent);
 413
 414         clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
 415         return 0;
 416 }
 417
 418 static int rtc_dev_fasync(int fd, struct file *file, int on)
 419 {
 420         struct rtc_device *rtc = file->private_data;
 421         return fasync_helper(fd, file, on, &rtc->async_queue);
 422 }
 423
 424 static const struct file_operations rtc_dev_fops = {
 425         .owner          = THIS_MODULE,
 426         .llseek         = no_llseek,
 427         .read           = rtc_dev_read,
 428         .poll           = rtc_dev_poll,
 429         .ioctl          = rtc_dev_ioctl,
 430         .open           = rtc_dev_open,
 431         .release        = rtc_dev_release,
 432         .fasync         = rtc_dev_fasync,
 433 };
 434
 435 /* insertion/removal hooks */
 436
 437 void rtc_dev_prepare(struct rtc_device *rtc)
 438 {
 439         if (!rtc_devt)
 440                 return;
 441
 442         if (rtc->id >= RTC_DEV_MAX) {
 443                 pr_debug("%s: too many RTC devices\n", rtc->name);
 444                 return;
 445         }
 446
 447         rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
 448
 449 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
 450         INIT_WORK(&rtc->uie_task, rtc_uie_task);
 451         setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
 452 #endif
 453
 454         cdev_init(&rtc->char_dev, &rtc_dev_fops);
 455         rtc->char_dev.owner = rtc->owner;
 456 }
 457
 458 void rtc_dev_add_device(struct rtc_device *rtc)
 459 {
 460         if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))
 461                 printk(KERN_WARNING "%s: failed to add char device %d:%d\n",
 462                         rtc->name, MAJOR(rtc_devt), rtc->id);
 463         else
 464                 pr_debug("%s: dev (%d:%d)\n", rtc->name,
 465                         MAJOR(rtc_devt), rtc->id);
 466 }
 467
 468 void rtc_dev_del_device(struct rtc_device *rtc)
 469 {
 470         if (rtc->dev.devt)
 471                 cdev_del(&rtc->char_dev);
 472 }
 473
 474 void __init rtc_dev_init(void)
 475 {
 476         int err;
 477
 478         err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
 479         if (err < 0)
 480                 printk(KERN_ERR "%s: failed to allocate char dev region\n",
 481                         __FILE__);
 482 }
 483
 484 void __exit rtc_dev_exit(void)
 485 {
 486         if (rtc_devt)
 487                 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
 488 }