arch/arm/common/rtctime.c

   1 /*
   2  *  linux/arch/arm/common/rtctime.c
   3  *
   4  *  Copyright (C) 2003 Deep Blue Solutions Ltd.
   5  *  Based on sa1100-rtc.c, Nils Faerber, CIH, Nicolas Pitre.
   6  *  Based on rtc.c by Paul Gortmaker
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/time.h>
  15 #include <linux/rtc.h>
  16 #include <linux/poll.h>
  17 #include <linux/proc_fs.h>
  18 #include <linux/miscdevice.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/capability.h>
  21 #include <linux/device.h>
  22 #include <linux/mutex.h>
  23
  24 #include <asm/rtc.h>
  25 #include <asm/semaphore.h>
  26
  27 static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
  28 static struct fasync_struct *rtc_async_queue;
  29
  30 /*
  31  * rtc_lock protects rtc_irq_data
  32  */
  33 static DEFINE_SPINLOCK(rtc_lock);
  34 static unsigned long rtc_irq_data;
  35
  36 /*
  37  * rtc_sem protects rtc_inuse and rtc_ops
  38  */
  39 static DEFINE_MUTEX(rtc_mutex);
  40 static unsigned long rtc_inuse;
  41 static struct rtc_ops *rtc_ops;
  42
  43 #define rtc_epoch 1900UL
  44
  45 static const unsigned char days_in_month[] = {
  46         31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
  47 };
  48
  49 #define LEAPS_THRU_END_OF(y) ((y)/4 - (y)/100 + (y)/400)
  50 #define LEAP_YEAR(year) ((!(year % 4) && (year % 100)) || !(year % 400))
  51
  52 static int month_days(unsigned int month, unsigned int year)
  53 {
  54         return days_in_month[month] + (LEAP_YEAR(year) && month == 1);
  55 }
  56
  57 /*
  58  * Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
  59  */
  60 void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
  61 {
  62         int days, month, year;
  63
  64         days = time / 86400;
  65         time -= days * 86400;
  66
  67         tm->tm_wday = (days + 4) % 7;
  68
  69         year = 1970 + days / 365;
  70         days -= (year - 1970) * 365
  71                 + LEAPS_THRU_END_OF(year - 1)
  72                 - LEAPS_THRU_END_OF(1970 - 1);
  73         if (days < 0) {
  74                 year -= 1;
  75                 days += 365 + LEAP_YEAR(year);
  76         }
  77         tm->tm_year = year - 1900;
  78         tm->tm_yday = days + 1;
  79
  80         for (month = 0; month < 11; month++) {
  81                 int newdays;
  82
  83                 newdays = days - month_days(month, year);
  84                 if (newdays < 0)
  85                         break;
  86                 days = newdays;
  87         }
  88         tm->tm_mon = month;
  89         tm->tm_mday = days + 1;
  90
  91         tm->tm_hour = time / 3600;
  92         time -= tm->tm_hour * 3600;
  93         tm->tm_min = time / 60;
  94         tm->tm_sec = time - tm->tm_min * 60;
  95 }
  96 EXPORT_SYMBOL(rtc_time_to_tm);
  97
  98 /*
  99  * Does the rtc_time represent a valid date/time?
 100  */
 101 int rtc_valid_tm(struct rtc_time *tm)
 102 {
 103         if (tm->tm_year < 70 ||
 104             tm->tm_mon >= 12 ||
 105             tm->tm_mday < 1 ||
 106             tm->tm_mday > month_days(tm->tm_mon, tm->tm_year + 1900) ||
 107             tm->tm_hour >= 24 ||
 108             tm->tm_min >= 60 ||
 109             tm->tm_sec >= 60)
 110                 return -EINVAL;
 111
 112         return 0;
 113 }
 114 EXPORT_SYMBOL(rtc_valid_tm);
 115
 116 /*
 117  * Convert Gregorian date to seconds since 01-01-1970 00:00:00.
 118  */
 119 int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
 120 {
 121         *time = mktime(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
 122                        tm->tm_hour, tm->tm_min, tm->tm_sec);
 123
 124         return 0;
 125 }
 126 EXPORT_SYMBOL(rtc_tm_to_time);
 127
 128 /*
 129  * Calculate the next alarm time given the requested alarm time mask
 130  * and the current time.
 131  *
 132  * FIXME: for now, we just copy the alarm time because we're lazy (and
 133  * is therefore buggy - setting a 10am alarm at 8pm will not result in
 134  * the alarm triggering.)
 135  */
 136 void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now, struct rtc_time *alrm)
 137 {
 138         next->tm_year = now->tm_year;
 139         next->tm_mon = now->tm_mon;
 140         next->tm_mday = now->tm_mday;
 141         next->tm_hour = alrm->tm_hour;
 142         next->tm_min = alrm->tm_min;
 143         next->tm_sec = alrm->tm_sec;
 144 }
 145
 146 static inline int rtc_read_time(struct rtc_ops *ops, struct rtc_time *tm)
 147 {
 148         memset(tm, 0, sizeof(struct rtc_time));
 149         return ops->read_time(tm);
 150 }
 151
 152 static inline int rtc_set_time(struct rtc_ops *ops, struct rtc_time *tm)
 153 {
 154         int ret;
 155
 156         ret = rtc_valid_tm(tm);
 157         if (ret == 0)
 158                 ret = ops->set_time(tm);
 159
 160         return ret;
 161 }
 162
 163 static inline int rtc_read_alarm(struct rtc_ops *ops, struct rtc_wkalrm *alrm)
 164 {
 165         int ret = -EINVAL;
 166         if (ops->read_alarm) {
 167                 memset(alrm, 0, sizeof(struct rtc_wkalrm));
 168                 ret = ops->read_alarm(alrm);
 169         }
 170         return ret;
 171 }
 172
 173 static inline int rtc_set_alarm(struct rtc_ops *ops, struct rtc_wkalrm *alrm)
 174 {
 175         int ret = -EINVAL;
 176         if (ops->set_alarm)
 177                 ret = ops->set_alarm(alrm);
 178         return ret;
 179 }
 180
 181 void rtc_update(unsigned long num, unsigned long events)
 182 {
 183         spin_lock(&rtc_lock);
 184         rtc_irq_data = (rtc_irq_data + (num << 8)) | events;
 185         spin_unlock(&rtc_lock);
 186
 187         wake_up_interruptible(&rtc_wait);
 188         kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
 189 }
 190 EXPORT_SYMBOL(rtc_update);
 191
 192
 193 static ssize_t
 194 rtc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 195 {
 196         DECLARE_WAITQUEUE(wait, current);
 197         unsigned long data;
 198         ssize_t ret;
 199
 200         if (count < sizeof(unsigned long))
 201                 return -EINVAL;
 202
 203         add_wait_queue(&rtc_wait, &wait);
 204         do {
 205                 __set_current_state(TASK_INTERRUPTIBLE);
 206
 207                 spin_lock_irq(&rtc_lock);
 208                 data = rtc_irq_data;
 209                 rtc_irq_data = 0;
 210                 spin_unlock_irq(&rtc_lock);
 211
 212                 if (data != 0) {
 213                         ret = 0;
 214                         break;
 215                 }
 216                 if (file->f_flags & O_NONBLOCK) {
 217                         ret = -EAGAIN;
 218                         break;
 219                 }
 220                 if (signal_pending(current)) {
 221                         ret = -ERESTARTSYS;
 222                         break;
 223                 }
 224                 schedule();
 225         } while (1);
 226         set_current_state(TASK_RUNNING);
 227         remove_wait_queue(&rtc_wait, &wait);
 228
 229         if (ret == 0) {
 230                 ret = put_user(data, (unsigned long __user *)buf);
 231                 if (ret == 0)
 232                         ret = sizeof(unsigned long);
 233         }
 234         return ret;
 235 }
 236
 237 static unsigned int rtc_poll(struct file *file, poll_table *wait)
 238 {
 239         unsigned long data;
 240
 241         poll_wait(file, &rtc_wait, wait);
 242
 243         spin_lock_irq(&rtc_lock);
 244         data = rtc_irq_data;
 245         spin_unlock_irq(&rtc_lock);
 246
 247         return data != 0 ? POLLIN | POLLRDNORM : 0;
 248 }
 249
 250 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 251                      unsigned long arg)
 252 {
 253         struct rtc_ops *ops = file->private_data;
 254         struct rtc_time tm;
 255         struct rtc_wkalrm alrm;
 256         void __user *uarg = (void __user *)arg;
 257         int ret = -EINVAL;
 258
 259         switch (cmd) {
 260         case RTC_ALM_READ:
 261                 ret = rtc_read_alarm(ops, &alrm);
 262                 if (ret)
 263                         break;
 264                 ret = copy_to_user(uarg, &alrm.time, sizeof(tm));
 265                 if (ret)
 266                         ret = -EFAULT;
 267                 break;
 268
 269         case RTC_ALM_SET:
 270                 ret = copy_from_user(&alrm.time, uarg, sizeof(tm));
 271                 if (ret) {
 272                         ret = -EFAULT;
 273                         break;
 274                 }
 275                 alrm.enabled = 0;
 276                 alrm.pending = 0;
 277                 alrm.time.tm_mday = -1;
 278                 alrm.time.tm_mon = -1;
 279                 alrm.time.tm_year = -1;
 280                 alrm.time.tm_wday = -1;
 281                 alrm.time.tm_yday = -1;
 282                 alrm.time.tm_isdst = -1;
 283                 ret = rtc_set_alarm(ops, &alrm);
 284                 break;
 285
 286         case RTC_RD_TIME:
 287                 ret = rtc_read_time(ops, &tm);
 288                 if (ret)
 289                         break;
 290                 ret = copy_to_user(uarg, &tm, sizeof(tm));
 291                 if (ret)
 292                         ret = -EFAULT;
 293                 break;
 294
 295         case RTC_SET_TIME:
 296                 if (!capable(CAP_SYS_TIME)) {
 297                         ret = -EACCES;
 298                         break;
 299                 }
 300                 ret = copy_from_user(&tm, uarg, sizeof(tm));
 301                 if (ret) {
 302                         ret = -EFAULT;
 303                         break;
 304                 }
 305                 ret = rtc_set_time(ops, &tm);
 306                 break;
 307
 308         case RTC_EPOCH_SET:
 309 #ifndef rtc_epoch
 310                 /*
 311                  * There were no RTC clocks before 1900.
 312                  */
 313                 if (arg < 1900) {
 314                         ret = -EINVAL;
 315                         break;
 316                 }
 317                 if (!capable(CAP_SYS_TIME)) {
 318                         ret = -EACCES;
 319                         break;
 320                 }
 321                 rtc_epoch = arg;
 322                 ret = 0;
 323 #endif
 324                 break;
 325
 326         case RTC_EPOCH_READ:
 327                 ret = put_user(rtc_epoch, (unsigned long __user *)uarg);
 328                 break;
 329
 330         case RTC_WKALM_SET:
 331                 ret = copy_from_user(&alrm, uarg, sizeof(alrm));
 332                 if (ret) {
 333                         ret = -EFAULT;
 334                         break;
 335                 }
 336                 ret = rtc_set_alarm(ops, &alrm);
 337                 break;
 338
 339         case RTC_WKALM_RD:
 340                 ret = rtc_read_alarm(ops, &alrm);
 341                 if (ret)
 342                         break;
 343                 ret = copy_to_user(uarg, &alrm, sizeof(alrm));
 344                 if (ret)
 345                         ret = -EFAULT;
 346                 break;
 347
 348         default:
 349                 if (ops->ioctl)
 350                         ret = ops->ioctl(cmd, arg);
 351                 break;
 352         }
 353         return ret;
 354 }
 355
 356 static int rtc_open(struct inode *inode, struct file *file)
 357 {
 358         int ret;
 359
 360         mutex_lock(&rtc_mutex);
 361
 362         if (rtc_inuse) {
 363                 ret = -EBUSY;
 364         } else if (!rtc_ops || !try_module_get(rtc_ops->owner)) {
 365                 ret = -ENODEV;
 366         } else {
 367                 file->private_data = rtc_ops;
 368
 369                 ret = rtc_ops->open ? rtc_ops->open() : 0;
 370                 if (ret == 0) {
 371                         spin_lock_irq(&rtc_lock);
 372                         rtc_irq_data = 0;
 373                         spin_unlock_irq(&rtc_lock);
 374
 375                         rtc_inuse = 1;
 376                 }
 377         }
 378         mutex_unlock(&rtc_mutex);
 379
 380         return ret;
 381 }
 382
 383 static int rtc_release(struct inode *inode, struct file *file)
 384 {
 385         struct rtc_ops *ops = file->private_data;
 386
 387         if (ops->release)
 388                 ops->release();
 389
 390         spin_lock_irq(&rtc_lock);
 391         rtc_irq_data = 0;
 392         spin_unlock_irq(&rtc_lock);
 393
 394         module_put(rtc_ops->owner);
 395         rtc_inuse = 0;
 396
 397         return 0;
 398 }
 399
 400 static int rtc_fasync(int fd, struct file *file, int on)
 401 {
 402         return fasync_helper(fd, file, on, &rtc_async_queue);
 403 }
 404
 405 static struct file_operations rtc_fops = {
 406         .owner          = THIS_MODULE,
 407         .llseek         = no_llseek,
 408         .read           = rtc_read,
 409         .poll           = rtc_poll,
 410         .ioctl          = rtc_ioctl,
 411         .open           = rtc_open,
 412         .release        = rtc_release,
 413         .fasync         = rtc_fasync,
 414 };
 415
 416 static struct miscdevice rtc_miscdev = {
 417         .minor          = RTC_MINOR,
 418         .name           = "rtc",
 419         .fops           = &rtc_fops,
 420 };
 421
 422
 423 static int rtc_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data)
 424 {
 425         struct rtc_ops *ops = data;
 426         struct rtc_wkalrm alrm;
 427         struct rtc_time tm;
 428         char *p = page;
 429
 430         if (rtc_read_time(ops, &tm) == 0) {
 431                 p += sprintf(p,
 432                         "rtc_time\t: %02d:%02d:%02d\n"
 433                         "rtc_date\t: %04d-%02d-%02d\n"
 434                         "rtc_epoch\t: %04lu\n",
 435                         tm.tm_hour, tm.tm_min, tm.tm_sec,
 436                         tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 437                         rtc_epoch);
 438         }
 439
 440         if (rtc_read_alarm(ops, &alrm) == 0) {
 441                 p += sprintf(p, "alrm_time\t: ");
 442                 if ((unsigned int)alrm.time.tm_hour <= 24)
 443                         p += sprintf(p, "%02d:", alrm.time.tm_hour);
 444                 else
 445                         p += sprintf(p, "**:");
 446                 if ((unsigned int)alrm.time.tm_min <= 59)
 447                         p += sprintf(p, "%02d:", alrm.time.tm_min);
 448                 else
 449                         p += sprintf(p, "**:");
 450                 if ((unsigned int)alrm.time.tm_sec <= 59)
 451                         p += sprintf(p, "%02d\n", alrm.time.tm_sec);
 452                 else
 453                         p += sprintf(p, "**\n");
 454
 455                 p += sprintf(p, "alrm_date\t: ");
 456                 if ((unsigned int)alrm.time.tm_year <= 200)
 457                         p += sprintf(p, "%04d-", alrm.time.tm_year + 1900);
 458                 else
 459                         p += sprintf(p, "****-");
 460                 if ((unsigned int)alrm.time.tm_mon <= 11)
 461                         p += sprintf(p, "%02d-", alrm.time.tm_mon + 1);
 462                 else
 463                         p += sprintf(p, "**-");
 464                 if ((unsigned int)alrm.time.tm_mday <= 31)
 465                         p += sprintf(p, "%02d\n", alrm.time.tm_mday);
 466                 else
 467                         p += sprintf(p, "**\n");
 468                 p += sprintf(p, "alrm_wakeup\t: %s\n",
 469                              alrm.enabled ? "yes" : "no");
 470                 p += sprintf(p, "alrm_pending\t: %s\n",
 471                              alrm.pending ? "yes" : "no");
 472         }
 473
 474         if (ops->proc)
 475                 p += ops->proc(p);
 476
 477         return p - page;
 478 }
 479
 480 int register_rtc(struct rtc_ops *ops)
 481 {
 482         int ret = -EBUSY;
 483
 484         mutex_lock(&rtc_mutex);
 485         if (rtc_ops == NULL) {
 486                 rtc_ops = ops;
 487
 488                 ret = misc_register(&rtc_miscdev);
 489                 if (ret == 0)
 490                         create_proc_read_entry("driver/rtc", 0, NULL,
 491                                                rtc_read_proc, ops);
 492         }
 493         mutex_unlock(&rtc_mutex);
 494
 495         return ret;
 496 }
 497 EXPORT_SYMBOL(register_rtc);
 498
 499 void unregister_rtc(struct rtc_ops *rtc)
 500 {
 501         mutex_lock(&rtc_mutex);
 502         if (rtc == rtc_ops) {
 503                 remove_proc_entry("driver/rtc", NULL);
 504                 misc_deregister(&rtc_miscdev);
 505                 rtc_ops = NULL;
 506         }
 507         mutex_unlock(&rtc_mutex);
 508 }
 509 EXPORT_SYMBOL(unregister_rtc);