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