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
 251         switch (cmd) {
 252         case RTC_ALM_READ:
 253                 err = rtc_read_alarm(rtc, &alarm);
 254                 if (err < 0)
 255                         return err;
 256
 257                 if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
 258                         return -EFAULT;
 259                 break;
 260
 261         case RTC_ALM_SET:
 262                 if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
 263                         return -EFAULT;
 264
 265                 alarm.enabled = 0;
 266                 alarm.pending = 0;
 267                 alarm.time.tm_wday = -1;
 268                 alarm.time.tm_yday = -1;
 269                 alarm.time.tm_isdst = -1;
 270
 271                 /* RTC_ALM_SET alarms may be up to 24 hours in the future.
 272                  * Rather than expecting every RTC to implement "don't care"
 273                  * for day/month/year fields, just force the alarm to have
 274                  * the right values for those fields.
 275                  *
 276                  * RTC_WKALM_SET should be used instead.  Not only does it
 277                  * eliminate the need for a separate RTC_AIE_ON call, it
 278                  * doesn't have the "alarm 23:59:59 in the future" race.
 279                  *
 280                  * NOTE:  some legacy code may have used invalid fields as
 281                  * wildcards, exposing hardware "periodic alarm" capabilities.
 282                  * Not supported here.
 283                  */
 284                 {
 285                         unsigned long now, then;
 286
 287                         err = rtc_read_time(rtc, &tm);
 288                         if (err < 0)
 289                                 return err;
 290                         rtc_tm_to_time(&tm, &now);
 291
 292                         alarm.time.tm_mday = tm.tm_mday;
 293                         alarm.time.tm_mon = tm.tm_mon;
 294                         alarm.time.tm_year = tm.tm_year;
 295                         err  = rtc_valid_tm(&alarm.time);
 296                         if (err < 0)
 297                                 return err;
 298                         rtc_tm_to_time(&alarm.time, &then);
 299
 300                         /* alarm may need to wrap into tomorrow */
 301                         if (then < now) {
 302                                 rtc_time_to_tm(now + 24 * 60 * 60, &tm);
 303                                 alarm.time.tm_mday = tm.tm_mday;
 304                                 alarm.time.tm_mon = tm.tm_mon;
 305                                 alarm.time.tm_year = tm.tm_year;
 306                         }
 307                 }
 308
 309                 err = rtc_set_alarm(rtc, &alarm);
 310                 break;
 311
 312         case RTC_RD_TIME:
 313                 err = rtc_read_time(rtc, &tm);
 314                 if (err < 0)
 315                         return err;
 316
 317                 if (copy_to_user(uarg, &tm, sizeof(tm)))
 318                         return -EFAULT;
 319                 break;
 320
 321         case RTC_SET_TIME:
 322                 if (copy_from_user(&tm, uarg, sizeof(tm)))
 323                         return -EFAULT;
 324
 325                 err = rtc_set_time(rtc, &tm);
 326                 break;
 327
 328         case RTC_PIE_ON:
 329                 err = rtc_irq_set_state(rtc, NULL, 1);
 330                 break;
 331
 332         case RTC_PIE_OFF:
 333                 err = rtc_irq_set_state(rtc, NULL, 0);
 334                 break;
 335
 336         case RTC_IRQP_SET:
 337                 err = rtc_irq_set_freq(rtc, NULL, arg);
 338                 break;
 339
 340         case RTC_IRQP_READ:
 341                 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
 342                 break;
 343
 344 #if 0
 345         case RTC_EPOCH_SET:
 346 #ifndef rtc_epoch
 347                 /*
 348                  * There were no RTC clocks before 1900.
 349                  */
 350                 if (arg < 1900) {
 351                         err = -EINVAL;
 352                         break;
 353                 }
 354                 rtc_epoch = arg;
 355                 err = 0;
 356 #endif
 357                 break;
 358
 359         case RTC_EPOCH_READ:
 360                 err = put_user(rtc_epoch, (unsigned long __user *)uarg);
 361                 break;
 362 #endif
 363         case RTC_WKALM_SET:
 364                 if (copy_from_user(&alarm, uarg, sizeof(alarm)))
 365                         return -EFAULT;
 366
 367                 err = rtc_set_alarm(rtc, &alarm);
 368                 break;
 369
 370         case RTC_WKALM_RD:
 371                 err = rtc_read_alarm(rtc, &alarm);
 372                 if (err < 0)
 373                         return err;
 374
 375                 if (copy_to_user(uarg, &alarm, sizeof(alarm)))
 376                         return -EFAULT;
 377                 break;
 378
 379 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
 380         case RTC_UIE_OFF:
 381                 clear_uie(rtc);
 382                 return 0;
 383
 384         case RTC_UIE_ON:
 385                 return set_uie(rtc);
 386 #endif
 387         default:
 388                 err = -ENOTTY;
 389                 break;
 390         }
 391
 392         return err;
 393 }
 394
 395 static int rtc_dev_release(struct inode *inode, struct file *file)
 396 {
 397         struct rtc_device *rtc = file->private_data;
 398
 399 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
 400         clear_uie(rtc);
 401 #endif
 402         if (rtc->ops->release)
 403                 rtc->ops->release(rtc->dev.parent);
 404
 405         clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
 406         return 0;
 407 }
 408
 409 static int rtc_dev_fasync(int fd, struct file *file, int on)
 410 {
 411         struct rtc_device *rtc = file->private_data;
 412         return fasync_helper(fd, file, on, &rtc->async_queue);
 413 }
 414
 415 static const struct file_operations rtc_dev_fops = {
 416         .owner          = THIS_MODULE,
 417         .llseek         = no_llseek,
 418         .read           = rtc_dev_read,
 419         .poll           = rtc_dev_poll,
 420         .ioctl          = rtc_dev_ioctl,
 421         .open           = rtc_dev_open,
 422         .release        = rtc_dev_release,
 423         .fasync         = rtc_dev_fasync,
 424 };
 425
 426 /* insertion/removal hooks */
 427
 428 void rtc_dev_prepare(struct rtc_device *rtc)
 429 {
 430         if (!rtc_devt)
 431                 return;
 432
 433         if (rtc->id >= RTC_DEV_MAX) {
 434                 pr_debug("%s: too many RTC devices\n", rtc->name);
 435                 return;
 436         }
 437
 438         rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
 439
 440 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
 441         INIT_WORK(&rtc->uie_task, rtc_uie_task);
 442         setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
 443 #endif
 444
 445         cdev_init(&rtc->char_dev, &rtc_dev_fops);
 446         rtc->char_dev.owner = rtc->owner;
 447 }
 448
 449 void rtc_dev_add_device(struct rtc_device *rtc)
 450 {
 451         if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1))
 452                 printk(KERN_WARNING "%s: failed to add char device %d:%d\n",
 453                         rtc->name, MAJOR(rtc_devt), rtc->id);
 454         else
 455                 pr_debug("%s: dev (%d:%d)\n", rtc->name,
 456                         MAJOR(rtc_devt), rtc->id);
 457 }
 458
 459 void rtc_dev_del_device(struct rtc_device *rtc)
 460 {
 461         if (rtc->dev.devt)
 462                 cdev_del(&rtc->char_dev);
 463 }
 464
 465 void __init rtc_dev_init(void)
 466 {
 467         int err;
 468
 469         err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
 470         if (err < 0)
 471                 printk(KERN_ERR "%s: failed to allocate char dev region\n",
 472                         __FILE__);
 473 }
 474
 475 void __exit rtc_dev_exit(void)
 476 {
 477         if (rtc_devt)
 478                 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
 479 }