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