/******************************************************************************
Copyright 2008-2010, Freie Universitaet Berlin (FUB). All rights reserved.

These sources were developed at the Freie Universitaet Berlin, Computer Systems
and Telematics group (http://cst.mi.fu-berlin.de).
-------------------------------------------------------------------------------
This file is part of RIOT.

This file subject to the terms and conditions of the GNU Lesser General Public
License. See the file LICENSE in the top level directory for more details.
*******************************************************************************/

/**
 * @file
 * @ingroup		lpc2387_rtc
 * @brief		LPC2387 Real-Time-Clock
 *
 * @author      Freie Universität Berlin, Computer Systems & Telematics
 * @author		Michael Baar <michael.baar@fu-berlin.de>
 * @version     $Revision: 2005 $
 *
 * @note   		$Id: lpc2387-rtc.c 2005 2010-03-17 10:52:03Z baar $
 */

#include <sys/time.h>
#include <stdint.h>
#include <string.h>

// cpu
#include "VIC.h"
#include "lpc2387.h"
#include "lpc2387-rtc.h"
#include "lpm.h"

#define PREINT_RTC	0x000001C8  /* Prescaler value, integer portion, PCLK = 15Mhz */
#define PREFRAC_RTC	0x000061C0  /* Prescaler value, fraction portion, PCLK = 15Mhz */

#define ENABLE_DEBUG 0
#include <debug.h>

/**
 * @brief	epoch time in hour granularity
 */
static volatile time_t epoch;

/*---------------------------------------------------------------------------*/
/**
 * @brief	Sets the current time in broken down format directly from to RTC
 * @param[in]	localt		Pointer to structure with time to set
 */
void
rtc_set_localtime(struct tm* localt)
{
	if( localt == NULL )
		return;

	/* set clock */
	RTC_SEC = localt->tm_sec;
	RTC_MIN = localt->tm_min;
	RTC_HOUR = localt->tm_hour;
	RTC_DOM = localt->tm_mday;
	RTC_DOW = localt->tm_wday;
	RTC_DOY = localt->tm_yday;
	RTC_MONTH = localt->tm_mon + 1;
	RTC_YEAR = localt->tm_year;
}
/*---------------------------------------------------------------------------*/
void rtc_set(time_t time) {
	struct tm* localt;
	localt = localtime(&time);						// convert seconds to broken-down time
	rtc_set_localtime(localt);
	epoch = time - localt->tm_sec - localt->tm_min * 60;
}
/*---------------------------------------------------------------------------*/
/// set clock to start of unix epoch
void rtc_reset(void)
{
    rtc_set(0);
	epoch = 0;
}
/*---------------------------------------------------------------------------*/
void
rtc_set_alarm(struct tm* localt, enum rtc_alarm_mask mask)
{
	if( localt != NULL ) {
		RTC_ALSEC = localt->tm_sec;
		RTC_ALMIN = localt->tm_min;
		RTC_ALHOUR = localt->tm_hour;
		RTC_ALDOM = localt->tm_mday;
		RTC_ALDOW = localt->tm_wday;
		RTC_ALDOY = localt->tm_yday;
		RTC_ALMON = localt->tm_mon + 1;
		RTC_ALYEAR = localt->tm_year;
		RTC_AMR = ~mask;											// set wich alarm fields to check
		DEBUG("alarm set %2lu.%2lu.%4lu  %2lu:%2lu:%2lu\n",
				RTC_ALDOM, RTC_ALMON, RTC_ALYEAR, RTC_ALHOUR, RTC_ALMIN, RTC_ALSEC);
	} else {
		RTC_AMR = 0xff;
	}
}
/*---------------------------------------------------------------------------*/
enum rtc_alarm_mask
rtc_get_alarm(struct tm* localt)
{
	if( localt != NULL ) {
		localt->tm_sec = RTC_ALSEC;
		localt->tm_min = RTC_ALMIN;
		localt->tm_hour = RTC_ALHOUR;
		localt->tm_mday = RTC_ALDOM;
		localt->tm_wday = RTC_ALDOW;
		localt->tm_yday = RTC_ALDOY;
		localt->tm_mon = RTC_ALMON - 1;
		localt->tm_year = RTC_ALYEAR;
		localt->tm_isdst = -1; // not available
	}
	return (~RTC_AMR) & 0xff;										// return which alarm fields are checked
}
/*---------------------------------------------------------------------------*/
void RTC_IRQHandler (void) __attribute__ ((interrupt("IRQ")));
void RTC_IRQHandler (void)
{
	lpm_begin_awake();
	if( RTC_ILR & ILR_RTSSF ) {
		// sub second interrupt (does not need flag-clearing)

	} else if( RTC_ILR & ILR_RTCCIF ) {
		// counter increase interrupt
		RTC_ILR |= ILR_RTCCIF;
		epoch += 60 * 60;					// add 1 hour

	} else if( RTC_ILR & ILR_RTCALF ) {
		RTC_ILR |= ILR_RTCALF;
		RTC_AMR = 0xff;						// disable alarm irq
		DEBUG("Ring\n");
		lpm_end_awake();
	}

	VICVectAddr = 0;						// Acknowledge Interrupt
}

/*---------------------------------------------------------------------------*/
void rtc_enable(void)
{
	RTC_ILR = (ILR_RTSSF | ILR_RTCCIF | ILR_RTCALF);	// clear interrupt flags
	RTC_CCR |= CCR_CLKEN;								// enable clock
	install_irq(RTC_INT, &RTC_IRQHandler, IRQP_RTC);	// install interrupt handler

	time_t now = rtc_time(NULL);
	epoch = now - (now % 3600);
}
/*---------------------------------------------------------------------------*/
void rtc_init(void)
{
	PCONP |= BIT9;
	RTC_AMR = 0xff;							// disable alarm irq
	RTC_CIIR = IMHOUR;						// enable increase irq
	RTC_CISS = 0;							// disable subsecond irq

	INTWAKE |= BIT15;						// rtc irq wakes up mcu from power down

	RTC_CCR = CCR_CLKSRC;				    // Clock from external 32 kHz Osc.

	/* initialize clock with valid unix compatible values
	 * If RTC_YEAR contains an value larger unix time_t we must reset. */
	if( RTC_YEAR > 2037 ) {
		rtc_reset();
	}

	DEBUG("%2lu.%2lu.%4lu  %2lu:%2lu:%2lu epoch %lu\n",
			RTC_DOM, RTC_MONTH, RTC_YEAR, RTC_HOUR, RTC_MIN, RTC_SEC,
			epoch);
}
/*---------------------------------------------------------------------------*/
time_t rtc_time(struct timeval* time)
{
	uint32_t sec;
	uint32_t usec;
	uint32_t min;

	usec = (RTC_CTC >> 1);
	sec  = RTC_SEC;
	min = RTC_MIN;
	while (usec != (RTC_CTC>>1) ) {
		usec = (RTC_CTC >> 1);
		sec  = RTC_SEC;
		min = RTC_MIN;
	}

	sec += min * 60;							// add number of minutes
	sec += epoch;								// add precalculated epoch in hour granularity

	if( time != NULL ) {
		usec = usec * 15625;
		usec >>= 9;
		time->tv_sec = sec;
		time->tv_usec =  usec;
	}

	return sec;
}
/*---------------------------------------------------------------------------*/
void rtc_disable(void)
{
	RTC_CCR &= ~CCR_CLKEN;	// disable clock
	install_irq(RTC_INT, NULL, 0);
	RTC_ILR = 0;
}
/*---------------------------------------------------------------------------*/
void
rtc_get_localtime(struct tm* localt)
{
	if( localt != NULL ) {
		localt->tm_sec = RTC_SEC;
		localt->tm_min = RTC_MIN;
		localt->tm_hour = RTC_HOUR;
		localt->tm_mday = RTC_DOM;
		localt->tm_wday = RTC_DOW;
		localt->tm_yday = RTC_DOY;
		localt->tm_mon = RTC_MONTH - 1;
		localt->tm_year = RTC_YEAR;
		localt->tm_isdst = -1; // not available
	}
}
/*---------------------------------------------------------------------------*/
void gettimeofday_r(struct _reent *r, struct timeval *ptimeval, struct timezone *ptimezone)
{
	r->_errno = 0;
	if( ptimeval != NULL ) {
		rtc_time(ptimeval);
	}
}