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 void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now, struct rtc_time *alrm)
 133 {
 134         unsigned long next_time;
 135         unsigned long now_time;
 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         rtc_tm_to_time(now, &now_time);
 145         rtc_tm_to_time(next, &next_time);
 146
 147         if (next_time < now_time) {
 148                 /* Advance one day */
 149                 next_time += 60 * 60 * 24;
 150                 rtc_time_to_tm(next_time, next);
 151         }
 152 }
 153
 154 static inline int rtc_read_time(struct rtc_ops *ops, struct rtc_time *tm)
 155 {
 156         memset(tm, 0, sizeof(struct rtc_time));
 157         return ops->read_time(tm);
 158 }
 159
 160 static inline int rtc_set_time(struct rtc_ops *ops, struct rtc_time *tm)
 161 {
 162         int ret;
 163
 164         ret = rtc_valid_tm(tm);
 165         if (ret == 0)
 166                 ret = ops->set_time(tm);
 167
 168         return ret;
 169 }
 170
 171 static inline int rtc_read_alarm(struct rtc_ops *ops, struct rtc_wkalrm *alrm)
 172 {
 173         int ret = -EINVAL;
 174         if (ops->read_alarm) {
 175                 memset(alrm, 0, sizeof(struct rtc_wkalrm));
 176                 ret = ops->read_alarm(alrm);
 177         }
 178         return ret;
 179 }
 180
 181 static inline int rtc_set_alarm(struct rtc_ops *ops, struct rtc_wkalrm *alrm)
 182 {
 183         int ret = -EINVAL;
 184         if (ops->set_alarm)
 185                 ret = ops->set_alarm(alrm);
 186         return ret;
 187 }
 188
 189 void rtc_update(unsigned long num, unsigned long events)
 190 {
 191         spin_lock(&rtc_lock);
 192         rtc_irq_data = (rtc_irq_data + (num << 8)) | events;
 193         spin_unlock(&rtc_lock);
 194
 195         wake_up_interruptible(&rtc_wait);
 196         kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
 197 }
 198 EXPORT_SYMBOL(rtc_update);
 199
 200
 201 static ssize_t
 202 rtc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 203 {
 204         DECLARE_WAITQUEUE(wait, current);
 205         unsigned long data;
 206         ssize_t ret;
 207
 208         if (count < sizeof(unsigned long))
 209                 return -EINVAL;
 210
 211         add_wait_queue(&rtc_wait, &wait);
 212         do {
 213                 __set_current_state(TASK_INTERRUPTIBLE);
 214
 215                 spin_lock_irq(&rtc_lock);
 216                 data = rtc_irq_data;
 217                 rtc_irq_data = 0;
 218                 spin_unlock_irq(&rtc_lock);
 219
 220                 if (data != 0) {
 221                         ret = 0;
 222                         break;
 223                 }
 224                 if (file->f_flags & O_NONBLOCK) {
 225                         ret = -EAGAIN;
 226                         break;
 227                 }
 228                 if (signal_pending(current)) {
 229                         ret = -ERESTARTSYS;
 230                         break;
 231                 }
 232                 schedule();
 233         } while (1);
 234         set_current_state(TASK_RUNNING);
 235         remove_wait_queue(&rtc_wait, &wait);
 236
 237         if (ret == 0) {
 238                 ret = put_user(data, (unsigned long __user *)buf);
 239                 if (ret == 0)
 240                         ret = sizeof(unsigned long);
 241         }
 242         return ret;
 243 }
 244
 245 static unsigned int rtc_poll(struct file *file, poll_table *wait)
 246 {
 247         unsigned long data;
 248
 249         poll_wait(file, &rtc_wait, wait);
 250
 251         spin_lock_irq(&rtc_lock);
 252         data = rtc_irq_data;
 253         spin_unlock_irq(&rtc_lock);
 254
 255         return data != 0 ? POLLIN | POLLRDNORM : 0;
 256 }
 257
 258 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 259                      unsigned long arg)
 260 {
 261         struct rtc_ops *ops = file->private_data;
 262         struct rtc_time tm;
 263         struct rtc_wkalrm alrm;
 264         void __user *uarg = (void __user *)arg;
 265         int ret = -EINVAL;
 266
 267         switch (cmd) {
 268         case RTC_ALM_READ:
 269                 ret = rtc_read_alarm(ops, &alrm);
 270                 if (ret)
 271                         break;
 272                 ret = copy_to_user(uarg, &alrm.time, sizeof(tm));
 273                 if (ret)
 274                         ret = -EFAULT;
 275                 break;
 276
 277         case RTC_ALM_SET:
 278                 ret = copy_from_user(&alrm.time, uarg, sizeof(tm));
 279                 if (ret) {
 280                         ret = -EFAULT;
 281                         break;
 282                 }
 283                 alrm.enabled = 0;
 284                 alrm.pending = 0;
 285                 alrm.time.tm_mday = -1;
 286                 alrm.time.tm_mon = -1;
 287                 alrm.time.tm_year = -1;
 288                 alrm.time.tm_wday = -1;
 289                 alrm.time.tm_yday = -1;
 290                 alrm.time.tm_isdst = -1;
 291                 ret = rtc_set_alarm(ops, &alrm);
 292                 break;
 293
 294         case RTC_RD_TIME:
 295                 ret = rtc_read_time(ops, &tm);
 296                 if (ret)
 297                         break;
 298                 ret = copy_to_user(uarg, &tm, sizeof(tm));
 299                 if (ret)
 300                         ret = -EFAULT;
 301                 break;
 302
 303         case RTC_SET_TIME:
 304                 if (!capable(CAP_SYS_TIME)) {
 305                         ret = -EACCES;
 306                         break;
 307                 }
 308                 ret = copy_from_user(&tm, uarg, sizeof(tm));
 309                 if (ret) {
 310                         ret = -EFAULT;
 311                         break;
 312                 }
 313                 ret = rtc_set_time(ops, &tm);
 314                 break;
 315
 316         case RTC_EPOCH_SET:
 317 #ifndef rtc_epoch
 318                 /*
 319                  * There were no RTC clocks before 1900.
 320                  */
 321                 if (arg < 1900) {
 322                         ret = -EINVAL;
 323                         break;
 324                 }
 325                 if (!capable(CAP_SYS_TIME)) {
 326                         ret = -EACCES;
 327                         break;
 328                 }
 329                 rtc_epoch = arg;
 330                 ret = 0;
 331 #endif
 332                 break;
 333
 334         case RTC_EPOCH_READ:
 335                 ret = put_user(rtc_epoch, (unsigned long __user *)uarg);
 336                 break;
 337
 338         case RTC_WKALM_SET:
 339                 ret = copy_from_user(&alrm, uarg, sizeof(alrm));
 340                 if (ret) {
 341                         ret = -EFAULT;
 342                         break;
 343                 }
 344                 ret = rtc_set_alarm(ops, &alrm);
 345                 break;
 346
 347         case RTC_WKALM_RD:
 348                 ret = rtc_read_alarm(ops, &alrm);
 349                 if (ret)
 350                         break;
 351                 ret = copy_to_user(uarg, &alrm, sizeof(alrm));
 352                 if (ret)
 353                         ret = -EFAULT;
 354                 break;
 355
 356         default:
 357                 if (ops->ioctl)
 358                         ret = ops->ioctl(cmd, arg);
 359                 break;
 360         }
 361         return ret;
 362 }
 363
 364 static int rtc_open(struct inode *inode, struct file *file)
 365 {
 366         int ret;
 367
 368         mutex_lock(&rtc_mutex);
 369
 370         if (rtc_inuse) {
 371                 ret = -EBUSY;
 372         } else if (!rtc_ops || !try_module_get(rtc_ops->owner)) {
 373                 ret = -ENODEV;
 374         } else {
 375                 file->private_data = rtc_ops;
 376
 377                 ret = rtc_ops->open ? rtc_ops->open() : 0;
 378                 if (ret == 0) {
 379                         spin_lock_irq(&rtc_lock);
 380                         rtc_irq_data = 0;
 381                         spin_unlock_irq(&rtc_lock);
 382
 383                         rtc_inuse = 1;
 384                 }
 385         }
 386         mutex_unlock(&rtc_mutex);
 387
 388         return ret;
 389 }
 390
 391 static int rtc_release(struct inode *inode, struct file *file)
 392 {
 393         struct rtc_ops *ops = file->private_data;
 394
 395         if (ops->release)
 396                 ops->release();
 397
 398         spin_lock_irq(&rtc_lock);
 399         rtc_irq_data = 0;
 400         spin_unlock_irq(&rtc_lock);
 401
 402         module_put(rtc_ops->owner);
 403         rtc_inuse = 0;
 404
 405         return 0;
 406 }
 407
 408 static int rtc_fasync(int fd, struct file *file, int on)
 409 {
 410         return fasync_helper(fd, file, on, &rtc_async_queue);
 411 }
 412
 413 static struct file_operations rtc_fops = {
 414         .owner          = THIS_MODULE,
 415         .llseek         = no_llseek,
 416         .read           = rtc_read,
 417         .poll           = rtc_poll,
 418         .ioctl          = rtc_ioctl,
 419         .open           = rtc_open,
 420         .release        = rtc_release,
 421         .fasync         = rtc_fasync,
 422 };
 423
 424 static struct miscdevice rtc_miscdev = {
 425         .minor          = RTC_MINOR,
 426         .name           = "rtc",
 427         .fops           = &rtc_fops,
 428 };
 429
 430
 431 static int rtc_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data)
 432 {
 433         struct rtc_ops *ops = data;
 434         struct rtc_wkalrm alrm;
 435         struct rtc_time tm;
 436         char *p = page;
 437
 438         if (rtc_read_time(ops, &tm) == 0) {
 439                 p += sprintf(p,
 440                         "rtc_time\t: %02d:%02d:%02d\n"
 441                         "rtc_date\t: %04d-%02d-%02d\n"
 442                         "rtc_epoch\t: %04lu\n",
 443                         tm.tm_hour, tm.tm_min, tm.tm_sec,
 444                         tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 445                         rtc_epoch);
 446         }
 447
 448         if (rtc_read_alarm(ops, &alrm) == 0) {
 449                 p += sprintf(p, "alrm_time\t: ");
 450                 if ((unsigned int)alrm.time.tm_hour <= 24)
 451                         p += sprintf(p, "%02d:", alrm.time.tm_hour);
 452                 else
 453                         p += sprintf(p, "**:");
 454                 if ((unsigned int)alrm.time.tm_min <= 59)
 455                         p += sprintf(p, "%02d:", alrm.time.tm_min);
 456                 else
 457                         p += sprintf(p, "**:");
 458                 if ((unsigned int)alrm.time.tm_sec <= 59)
 459                         p += sprintf(p, "%02d\n", alrm.time.tm_sec);
 460                 else
 461                         p += sprintf(p, "**\n");
 462
 463                 p += sprintf(p, "alrm_date\t: ");
 464                 if ((unsigned int)alrm.time.tm_year <= 200)
 465                         p += sprintf(p, "%04d-", alrm.time.tm_year + 1900);
 466                 else
 467                         p += sprintf(p, "****-");
 468                 if ((unsigned int)alrm.time.tm_mon <= 11)
 469                         p += sprintf(p, "%02d-", alrm.time.tm_mon + 1);
 470                 else
 471                         p += sprintf(p, "**-");
 472                 if ((unsigned int)alrm.time.tm_mday <= 31)
 473                         p += sprintf(p, "%02d\n", alrm.time.tm_mday);
 474                 else
 475                         p += sprintf(p, "**\n");
 476                 p += sprintf(p, "alrm_wakeup\t: %s\n",
 477                              alrm.enabled ? "yes" : "no");
 478                 p += sprintf(p, "alrm_pending\t: %s\n",
 479                              alrm.pending ? "yes" : "no");
 480         }
 481
 482         if (ops->proc)
 483                 p += ops->proc(p);
 484
 485         return p - page;
 486 }
 487
 488 int register_rtc(struct rtc_ops *ops)
 489 {
 490         int ret = -EBUSY;
 491
 492         mutex_lock(&rtc_mutex);
 493         if (rtc_ops == NULL) {
 494                 rtc_ops = ops;
 495
 496                 ret = misc_register(&rtc_miscdev);
 497                 if (ret == 0)
 498                         create_proc_read_entry("driver/rtc", 0, NULL,
 499                                                rtc_read_proc, ops);
 500         }
 501         mutex_unlock(&rtc_mutex);
 502
 503         return ret;
 504 }
 505 EXPORT_SYMBOL(register_rtc);
 506
 507 void unregister_rtc(struct rtc_ops *rtc)
 508 {
 509         mutex_lock(&rtc_mutex);
 510         if (rtc == rtc_ops) {
 511                 remove_proc_entry("driver/rtc", NULL);
 512                 misc_deregister(&rtc_miscdev);
 513                 rtc_ops = NULL;
 514         }
 515         mutex_unlock(&rtc_mutex);
 516 }
 517 EXPORT_SYMBOL(unregister_rtc);