Turn off Beagle Bone am355x using the RTC TIMER2

softdown.c

#define RTC_SS_BASE 0x44e3e000L

#define SECONDS_REG 			0x00
#define MINUTES_REG				0x04
#define HOURS_REG				0x08
#define DAYS_REG				0x0C
#define MONTHS_REG 				0x10
#define YEARS_REG				0x14

#define ALARM_SECONDS_REG 		0x20
#define ALARM_MINUTES_REG		0x24
#define ALARM_HOURS_REG			0x28
#define ALARM_DAYS_REG			0x2C
#define ALARM_MONTHS_REG 		0x30
#define ALARM_YEARS_REG			0x34

#define ALARM2_SECONDS_REG 		0x80
#define ALARM2_MINUTES_REG		0x84
#define ALARM2_HOURS_REG		0x88
#define ALARM2_DAYS_REG			0x8C
#define ALARM2_MONTHS_REG 		0x90
#define ALARM2_YEARS_REG		0x94

#define RTCALARMINT 			76			// RTC alarm interrupt

#define RTC_CTRL_REG			0x40

#define RTC_STATUS_REG			0x44
#define RTC_STATUS_ALARM		(1<<6)		// Indicates ALARM has happened

#define RTC_INTERRUPTS_REG		0x48
#define RTC_INTERRUPTS_IT_ALARM2 (1<<4)		// Enable interrupt on ALARM2
#define RTC_INTERRUPTS_IT_ALARM	 (1<<3)		// Enable interrupt on ALARM
#define RTC_INTERRUPTS_IT_TIMER	 (1<<2)		// Enable interrupt on TIMER

#define RTC_SYSCONFIG			0x78
#define RTC_IRQWAKEEN			0x7c
#define RTC_IRQWAKEEN_ALARM		(1<<1)		// Allow wakeup generation on ALARM
#define RTC_IRQWAKEEN_TIMER		(1<<0)		// Allow wakeup generation on TIMER

#define RTC_PMIC				0x98
#define RTC_PMIC_PWN_ENABLE_EN	(1<<16)

#define ASSIGN_WORD(w,v) ((*( (unsigned long *) (&(w)) ) ) = (v) )


/*
 *
 * Based on: 
 * devmem2.c: Simple program to read/write from/to any location in memory.
 *
 *  Copyright (C) 2000, Jan-Derk Bakker ([email protected])
 *
 *
 * This software has been developed for the LART computing board
 * (http://www.lart.tudelft.nl/). The development has been sponsored by
 * the Mobile MultiMedia Communications (http://www.mmc.tudelft.nl/)
 * and Ubiquitous Communications (http://www.ubicom.tudelft.nl/)
 * projects.
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <fcntl.h>
#include <ctype.h>
#include <termios.h>
#include <sys/types.h>
#include <sys/mman.h>

#define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", \
  __LINE__, __FILE__, errno, strerror(errno)); exit(1); } while(0)

#define MAP_SIZE 4096UL
#define MAP_MASK (MAP_SIZE - 1)

int   bcd2n(  int bcd ) {
	
	return ((bcd/16) * 10 ) + ( bcd & 15);
	
}

int n2bcd( int n ) {
	
	return (( n / 10 ) * 16 ) + (n % 10 );
	
}

int main(int argc, char **argv) {
    int fd;
    void *map_base, *virt_addr;
    unsigned long read_result, writeval;
    off_t target;
   
    target = RTC_SS_BASE;
    
    if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1) FATAL;
    printf("/dev/mem opened.\n");
    fflush(stdout);

    /* Map one page */
    map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, target );
    if(map_base == (void *) -1) FATAL;
    printf("Memory mapped at address %p.\n", map_base);
    fflush(stdout);

	unsigned char *base = (unsigned char *) map_base;
	
    printf("Value at address %d\n", *base );
    fflush(stdout);

	// HERE IS THE BEEF
	
	printf("Turn off PMIC OFF bit...\n");
	system("i2cset -f -y 0 0x24 0x0a 0x00");			// Turn off OFF bit

	printf("First lets set the alarm...\n");
	
	printf("Get current time ...\n");
		
	int secs   = bcd2n( base[ SECONDS_REG] );
	int mins   = bcd2n( base[ MINUTES_REG] );
	int hours  = bcd2n( base[ HOURS_REG ] );
	int days   = bcd2n( base[ DAYS_REG ] );
	int months = bcd2n( base[ MONTHS_REG ] );
	int years  = bcd2n( base[ YEARS_REG ] );

	printf("Bump forward 5 secs in the future......\n");
	
	secs += 5;
	
	if (secs >= 60 ) {
		
		secs %= 60;
		
		mins++;
		
		if (mins >= 60 ) {
			
			mins %=60; 
			
			hours++;
			
			if (hours >=24 ) {
				
				hours %=24;
				
				days++;
				
				// TODO: Make work last day of the month at midnight
			}
		}
	}
	/*
	
	printf("Set ALARM for wakeup......\n");
		
	base[ALARM_SECONDS_REG]  = n2bcd( secs );
	base[ALARM_MINUTES_REG]  = n2bcd( mins );
	base[ALARM_HOURS_REG]    = n2bcd( hours );
	base[ALARM_DAYS_REG]     = n2bcd( days );
	base[ALARM_MONTHS_REG]   = n2bcd( months );
	base[ALARM_YEARS_REG]    = n2bcd( years );
	
	printf("NOW ALARM\n");
	printf("%3.3d %3.3d\n" , base[ SECONDS_REG], base[ ALARM_SECONDS_REG] );
 	printf("%3.3d %3.3d\n" , base[ MINUTES_REG], base[ ALARM_MINUTES_REG] );
 	printf("%3.3d %3.3d\n" , base[ HOURS_REG], base[ ALARM_HOURS_REG] );
 	printf("%3.3d %3.3d\n" , base[ DAYS_REG], base[ ALARM_DAYS_REG] );
 	printf("%3.3d %3.3d\n" , base[ MONTHS_REG], base[ ALARM_MONTHS_REG] );
 	printf("%3.3d %3.3d\n" , base[ YEARS_REG], base[ ALARM_YEARS_REG] );
 
	printf(" Enable ALARM interrupt (necessary?)... \n");
 
	base[ RTC_INTERRUPTS_REG ] |= RTC_INTERRUPTS_IT_ALARM;
	
	printf("Enable PWR_ENABLE_EN to be controlled ON->OFF by ALARM2...\n");
	
	base[RTC_PMIC] |= RTC_PMIC_PWN_ENABLE_EN;
	
	base[RTC_IRQWAKEEN ] |= RTC_IRQWAKEEN_ALARM;
	
	*/
	
	printf("Set ALARM2 for sleep......\n");
		
	base[ALARM2_SECONDS_REG]  = n2bcd( secs );
	base[ALARM2_MINUTES_REG]  = n2bcd( mins );
	base[ALARM2_HOURS_REG]    = n2bcd( hours );
	base[ALARM2_DAYS_REG]     = n2bcd( days );
	base[ALARM2_MONTHS_REG]   = n2bcd( months );
	base[ALARM2_YEARS_REG]    = n2bcd( years );
	
	printf("NOW ALARM2\n");
	printf("%3.3d %3.3d\n" , base[ SECONDS_REG], base[ ALARM2_SECONDS_REG] );
 	printf("%3.3d %3.3d\n" , base[ MINUTES_REG], base[ ALARM2_MINUTES_REG] );
 	printf("%3.3d %3.3d\n" , base[ HOURS_REG], base[ ALARM2_HOURS_REG] );
 	printf("%3.3d %3.3d\n" , base[ DAYS_REG], base[ ALARM2_DAYS_REG] );
 	printf("%3.3d %3.3d\n" , base[ MONTHS_REG], base[ ALARM2_MONTHS_REG] );
 	printf("%3.3d %3.3d\n" , base[ YEARS_REG], base[ ALARM2_YEARS_REG] );
 


	//base[RTC_IRQWAKEEN ] |= RTC_IRQWAKEEN_ALARM;

	printf("DONE setting Alarm time...\n");
	
	
	printf("Enable PWR_ENABLE_EN to be controlled ON->OFF by ALARM2...\n");	
	ASSIGN_WORD( base[RTC_PMIC] , RTC_PMIC_PWN_ENABLE_EN );
	
	// Check with...
	//  devmem2 0x44e3e098
	
	//printf("Enable Wake pin, invert polarity, PWR_ENABLE_EN to be controlled ON->OFF by ALARM2...\n");	
	//base[RTC_PMIC]=0x10011;				//Enable wakeup pin, invert polarity, POWER_ENABLE_EN
		
	printf(" Enable ALARM2 interrupt (necessary?)... \n");
	ASSIGN_WORD( base[ RTC_INTERRUPTS_REG ] , RTC_INTERRUPTS_IT_ALARM2 );	
		
	    	
	/*
	
	for(int i=0; i<15;i++) {
		printf("%d-%d\n",i, base[RTC_STATUS_REG] & RTC_STATUS_ALARM  );
	
		sleep(1);
		
	}
	*/
	
	printf("Close memmap...\n");

    if(munmap(map_base, MAP_SIZE) == -1) FATAL;
    close(fd);	
	
	// Now got to sleep!
	
//	system("devmem2 0x44e3e098 w 0x10011");				//Enable wakeup pin, invert polarity, POWER_ENABLE_EN
	 


	
//	system("i2cset -f -y 0 0x24 0x0a 0x080");			// Turn on OFF bit
	
//	system("i2cset -f -y 0 0x24 0x0b 0x63");			// PAssword to access 1e
	
	//printf("Sending SEQDWN+SEQUP...\n");
	//system("i2cset -f -y 0 0x24 0x1e 0x06");			// Set DWNSEQ bit to start shutdown sequence
	
	
	//system("i2cset -f -y 0 0x24 0x1e 0x02");			// Set DWNSEQ bit to start shutdown sequence

	printf("Waiting for turnoff via TIMER2 in 5 seconds!...\n");
	
	//__asm__ __volatile__ ("cpsie i"); /* Clear PRIMASK */
	
	
    return 0;
}