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 void rtc_read_time(struct rtc_ops *ops, struct rtc_time *tm)
 145 {
 146         memset(tm, 0, sizeof(struct rtc_time));
 147         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                 ops->read_alarm(alrm);
 167                 ret = 0;
 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                 rtc_read_time(ops, &tm);
 287                 ret = copy_to_user(uarg, &tm, sizeof(tm));
 288                 if (ret)
 289                         ret = -EFAULT;
 290                 break;
 291
 292         case RTC_SET_TIME:
 293                 if (!capable(CAP_SYS_TIME)) {
 294                         ret = -EACCES;
 295                         break;
 296                 }
 297                 ret = copy_from_user(&tm, uarg, sizeof(tm));
 298                 if (ret) {
 299                         ret = -EFAULT;
 300                         break;
 301                 }
 302                 ret = rtc_set_time(ops, &tm);
 303                 break;
 304
 305         case RTC_EPOCH_SET:
 306 #ifndef rtc_epoch
 307                 /*
 308                  * There were no RTC clocks before 1900.
 309                  */
 310                 if (arg < 1900) {
 311                         ret = -EINVAL;
 312                         break;
 313                 }
 314                 if (!capable(CAP_SYS_TIME)) {
 315                         ret = -EACCES;
 316                         break;
 317                 }
 318                 rtc_epoch = arg;
 319                 ret = 0;
 320 #endif
 321                 break;
 322
 323         case RTC_EPOCH_READ:
 324                 ret = put_user(rtc_epoch, (unsigned long __user *)uarg);
 325                 break;
 326
 327         case RTC_WKALM_SET:
 328                 ret = copy_from_user(&alrm, uarg, sizeof(alrm));
 329                 if (ret) {
 330                         ret = -EFAULT;
 331                         break;
 332                 }
 333                 ret = rtc_set_alarm(ops, &alrm);
 334                 break;
 335
 336         case RTC_WKALM_RD:
 337                 ret = rtc_read_alarm(ops, &alrm);
 338                 if (ret)
 339                         break;
 340                 ret = copy_to_user(uarg, &alrm, sizeof(alrm));
 341                 if (ret)
 342                         ret = -EFAULT;
 343                 break;
 344
 345         default:
 346                 if (ops->ioctl)
 347                         ret = ops->ioctl(cmd, arg);
 348                 break;
 349         }
 350         return ret;
 351 }
 352
 353 static int rtc_open(struct inode *inode, struct file *file)
 354 {
 355         int ret;
 356
 357         down(&rtc_sem);
 358
 359         if (rtc_inuse) {
 360                 ret = -EBUSY;
 361         } else if (!rtc_ops || !try_module_get(rtc_ops->owner)) {
 362                 ret = -ENODEV;
 363         } else {
 364                 file->private_data = rtc_ops;
 365
 366                 ret = rtc_ops->open ? rtc_ops->open() : 0;
 367                 if (ret == 0) {
 368                         spin_lock_irq(&rtc_lock);
 369                         rtc_irq_data = 0;
 370                         spin_unlock_irq(&rtc_lock);
 371
 372                         rtc_inuse = 1;
 373                 }
 374         }
 375         up(&rtc_sem);
 376
 377         return ret;
 378 }
 379
 380 static int rtc_release(struct inode *inode, struct file *file)
 381 {
 382         struct rtc_ops *ops = file->private_data;
 383
 384         if (ops->release)
 385                 ops->release();
 386
 387         spin_lock_irq(&rtc_lock);
 388         rtc_irq_data = 0;
 389         spin_unlock_irq(&rtc_lock);
 390
 391         module_put(rtc_ops->owner);
 392         rtc_inuse = 0;
 393
 394         return 0;
 395 }
 396
 397 static int rtc_fasync(int fd, struct file *file, int on)
 398 {
 399         return fasync_helper(fd, file, on, &rtc_async_queue);
 400 }
 401
 402 static struct file_operations rtc_fops = {
 403         .owner          = THIS_MODULE,
 404         .llseek         = no_llseek,
 405         .read           = rtc_read,
 406         .poll           = rtc_poll,
 407         .ioctl          = rtc_ioctl,
 408         .open           = rtc_open,
 409         .release        = rtc_release,
 410         .fasync         = rtc_fasync,
 411 };
 412
 413 static struct miscdevice rtc_miscdev = {
 414         .minor          = RTC_MINOR,
 415         .name           = "rtc",
 416         .fops           = &rtc_fops,
 417 };
 418
 419
 420 static int rtc_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data)
 421 {
 422         struct rtc_ops *ops = data;
 423         struct rtc_wkalrm alrm;
 424         struct rtc_time tm;
 425         char *p = page;
 426
 427         rtc_read_time(ops, &tm);
 428
 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         if (rtc_read_alarm(ops, &alrm) == 0) {
 438                 p += sprintf(p, "alrm_time\t: ");
 439                 if ((unsigned int)alrm.time.tm_hour <= 24)
 440                         p += sprintf(p, "%02d:", alrm.time.tm_hour);
 441                 else
 442                         p += sprintf(p, "**:");
 443                 if ((unsigned int)alrm.time.tm_min <= 59)
 444                         p += sprintf(p, "%02d:", alrm.time.tm_min);
 445                 else
 446                         p += sprintf(p, "**:");
 447                 if ((unsigned int)alrm.time.tm_sec <= 59)
 448                         p += sprintf(p, "%02d\n", alrm.time.tm_sec);
 449                 else
 450                         p += sprintf(p, "**\n");
 451
 452                 p += sprintf(p, "alrm_date\t: ");
 453                 if ((unsigned int)alrm.time.tm_year <= 200)
 454                         p += sprintf(p, "%04d-", alrm.time.tm_year + 1900);
 455                 else
 456                         p += sprintf(p, "****-");
 457                 if ((unsigned int)alrm.time.tm_mon <= 11)
 458                         p += sprintf(p, "%02d-", alrm.time.tm_mon + 1);
 459                 else
 460                         p += sprintf(p, "**-");
 461                 if ((unsigned int)alrm.time.tm_mday <= 31)
 462                         p += sprintf(p, "%02d\n", alrm.time.tm_mday);
 463                 else
 464                         p += sprintf(p, "**\n");
 465                 p += sprintf(p, "alrm_wakeup\t: %s\n",
 466                              alrm.enabled ? "yes" : "no");
 467                 p += sprintf(p, "alrm_pending\t: %s\n",
 468                              alrm.pending ? "yes" : "no");
 469         }
 470
 471         if (ops->proc)
 472                 p += ops->proc(p);
 473
 474         return p - page;
 475 }
 476
 477 int register_rtc(struct rtc_ops *ops)
 478 {
 479         int ret = -EBUSY;
 480
 481         down(&rtc_sem);
 482         if (rtc_ops == NULL) {
 483                 rtc_ops = ops;
 484
 485                 ret = misc_register(&rtc_miscdev);
 486                 if (ret == 0)
 487                         create_proc_read_entry("driver/rtc", 0, NULL,
 488                                                rtc_read_proc, ops);
 489         }
 490         up(&rtc_sem);
 491
 492         return ret;
 493 }
 494 EXPORT_SYMBOL(register_rtc);
 495
 496 void unregister_rtc(struct rtc_ops *rtc)
 497 {
 498         down(&rtc_sem);
 499         if (rtc == rtc_ops) {
 500                 remove_proc_entry("driver/rtc", NULL);
 501                 misc_deregister(&rtc_miscdev);
 502                 rtc_ops = NULL;
 503         }
 504         up(&rtc_sem);
 505 }
 506 EXPORT_SYMBOL(unregister_rtc);