time_rtc.c

/**
 * \brief <sys/time.h> functions implementation
 * Please use functions from <time.h> to access the rtc.
 */

#include <time.h>
#include <sys/time.h>
#include <reent.h>
#include <errno.h>

#include "stm32/stm32f4xx_pwr.h"
#include "stm32/stm32f4xx_rcc.h"
#include "stm32/stm32f4xx_rtc.h"
#include "heivs/error.h"

#define _SEC_IN_MINUTE 60L
#define _SEC_IN_HOUR 3600L
#define _SEC_IN_DAY 86400L
#define YEAR_BASE 1900

static const int _DAYS_BEFORE_MONTH[12] =
{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};

#define _ISLEAP(y) (((y) % 4) == 0 && (((y) % 100) != 0 || (((y)+1900) % 400) == 0))
#define _DAYS_IN_YEAR(year) (_ISLEAP(year) ? 366 : 365)

static time_t timegm(struct tm *tim_p)
{
  time_t tim = 0;
  long days = 0;
  int year, isdst=0;

  /* compute hours, minutes, seconds */
  tim += tim_p->tm_sec + (tim_p->tm_min * _SEC_IN_MINUTE) +
    (tim_p->tm_hour * _SEC_IN_HOUR);

  /* compute days in year */
  days += tim_p->tm_mday - 1;
  days += _DAYS_BEFORE_MONTH[tim_p->tm_mon];
  if (tim_p->tm_mon > 1 && _DAYS_IN_YEAR (tim_p->tm_year) == 366)
    days++;

  /* compute day of the year */
  tim_p->tm_yday = days;

  if (tim_p->tm_year > 10000 || tim_p->tm_year < -10000)
      return (time_t) -1;

  /* compute days in other years */
  if ((year = tim_p->tm_year) > 70)
    {
      for (year = 70; year < tim_p->tm_year; year++)
    days += _DAYS_IN_YEAR (year);
    }
  else if (year < 70)
    {
      for (year = 69; year > tim_p->tm_year; year--)
    days -= _DAYS_IN_YEAR (year);
      days -= _DAYS_IN_YEAR (year);
    }

  /* compute total seconds */
  tim += (days * _SEC_IN_DAY);

  /* reset isdst flag to what we have calculated */
  tim_p->tm_isdst = isdst;

  /* compute day of the week */
  if ((tim_p->tm_wday = (days + 4) % 7) < 0)
    tim_p->tm_wday += 7;

  return tim;
}

int _gettimeofday_r(struct _reent *ptr, struct timeval *tv, void *tz)
{
    struct tm tm;
    status_e status;
    RTC_TimeTypeDef time;
    RTC_DateTypeDef date;
    uint32_t subsecond;
    uint32_t prediv_s;

    (void)tz;

    // Read in this order is safe
    subsecond = RTC->SSR;
    RTC_GetTime(RTC_Format_BIN,&time);
    RTC_GetDate(RTC_Format_BIN,&date);

    status = NO_ERROR;
    if (status != NO_ERROR)
    {
        ptr->_errno = -EFAULT;
        return -1;
    }

    tm.tm_hour = time.RTC_Hours;
    tm.tm_min = time.RTC_Minutes;
    tm.tm_sec = time.RTC_Seconds;
    tm.tm_mon = date.RTC_Month - 1;
    tm.tm_mday = date.RTC_Date;
    tm.tm_year = 100 + date.RTC_Year;

    /* Ignored by mktime */
    tm.tm_wday = 0;
    tm.tm_yday = 0;

    tv->tv_sec = timegm(&tm);

    prediv_s = (RTC->PRER & RTC_PRER_PREDIV_S);
    tv->tv_usec = 1000000*(prediv_s - subsecond)/(prediv_s + 1);

    return 0;
}

/**
 * \brief Initialize the RTC and set the date and time
 *
 * \param theTime the time
 * \param theDate the date
 */
static void RTC_Set(RTC_TimeTypeDef * theTime, RTC_DateTypeDef * theDate)
{
    ErrorStatus stm32_status;

    PWR_BackupAccessCmd(ENABLE);
    RCC_LSEConfig(RCC_LSE_ON);                  // turn ON 32.768 kHz oscillator
    RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);     // set RTC clock is LSE clock
    RCC_RTCCLKCmd(ENABLE);  // optional ?

    RTC_WriteProtectionCmd(DISABLE);
    do
    {
        stm32_status = RTC_EnterInitMode();
    } while (stm32_status == ERROR);

    stm32_status = RTC_SetTime(RTC_Format_BIN,theTime);
    stm32_status = RTC_SetDate(RTC_Format_BIN,theDate);

    RTC_ExitInitMode();
    RTC_WriteProtectionCmd(ENABLE);
    PWR_BackupAccessCmd(DISABLE);
}

int settimeofday(const struct timeval *tv, const struct timezone *tz)
{
    RTC_TimeTypeDef time;
    RTC_DateTypeDef date;

    struct tm tm;

    (void)tz;
    gmtime_r(&tv->tv_sec, &tm);

    time.RTC_Hours = tm.tm_hour;
    time.RTC_Minutes = tm.tm_min;
    time.RTC_Seconds = tm.tm_sec;
    date.RTC_Month = tm.tm_mon + 1;
    date.RTC_Date = tm.tm_mday;
    date.RTC_Year = tm.tm_year % 100;
    date.RTC_WeekDay = (tm.tm_wday == 0) ? 7 : tm.tm_wday;

    RTC_Set(&time, &date);

    return 0;
}

/* Europe/Zurich */
static __tzinfo_type tzinfo =
{
    1, 0,
    {
        {'M', 3, 5, 0, 7200, (time_t)0, -3600 },    //CET, March, Last week, Sunday, 2:00 o´clock, -1 hour to UTC
        {'M', 10, 5, 0, 10800, (time_t)0, -7200 }   //CET, October, Last week, Sunday, 3:00 o´clock, -2 hours to UTC
    }
};

__tzinfo_type *__gettzinfo(void)
{
    return &tzinfo;
}