#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <signal.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/time.h>
#include <time.h>
#include <hw/inout.h>

#define PG_SZ 0x1000
#define PAD_CONF_BASE 0x48002000
#define PWM_PAD_9 0x0B4
#define PAD_MUX_MODE_3 3
#define TIMER_9_BASE 0x49040000
#define TIMER_TCLR 0x24
#define TIMER_START 1
#define TIMER_AUTORELOAD 2
#define TIMER_CE (1<<6)
#define TIMER_SCPWM (1<<7)
#define TIMER_PT (1<<12)
#define TIMER_TRG (2<<10)
#define TIMER_TCCR 0x28
#define TIMER_TLDR 0x2c
#define TIMER_TMAR 0x38

#define CLK_BASE 0x48005000
#define EN_GPT9 (1<<10)
#define CLKSEL_GPT9 (1<<7)

#define SYS_CLK 26000000UL

static int keep_running = 1;

void sighandler(int sig)
{
	keep_running = 0;
}

/* FREQUENCY = GPTi_FCLK / ((0xFFFF FFFF - TLDR) + 1)
 * TLDR = (0xFFFF FFFF - (GPTi_FCLK / FREQUENCY)) + 1
 * NUM_SETTINGS = 0xFFFF FFFE - TLDR
 * TMAR = TLDR + (NUM_SETTINGS * DUTY_CYCLE_PERCENTAGE)
 */
int main(int argc, char *argv[]) {
	uintptr_t timer_ptr;
	uint32_t tmp32, tldr, tmar, num_settings, freq_khz = 1, duty_cycle_percentage = 50;
	char opt;

	while((opt = getopt(argc, argv, "f:p:")) != -1) {
	 switch(opt) {
	 case 'f':
		 freq_khz = atoi(optarg);
		 break;
	 case 'p':
		 duty_cycle_percentage = atoi(optarg);
		 break;
	 }
	}
	tldr = (0xffffffff - (SYS_CLK / (freq_khz * 1000))) + 1;
	num_settings = 0xfffffffe - tldr;
	tmar = tldr + ( (num_settings * duty_cycle_percentage) / 100 );

	// set up the output pad
	timer_ptr = mmap_device_io(PG_SZ, PAD_CONF_BASE);
	tmp32 = in32(timer_ptr + PWM_PAD_9);
	tmp32 &= 0xffff;
	tmp32 |= (PAD_MUX_MODE_3<<16);
	out32(timer_ptr + PWM_PAD_9, tmp32);
	munmap_device_io(timer_ptr, PG_SZ);

	// turn on the clocks
	timer_ptr = mmap_device_io(PG_SZ, CLK_BASE);
	tmp32 = in32(timer_ptr);
	tmp32 |= EN_GPT9;
	out32(timer_ptr, tmp32);
	tmp32 = in32(timer_ptr + 0x10);
	tmp32 |= EN_GPT9;
	out32(timer_ptr + 0x10, tmp32);
	tmp32 = in32(timer_ptr + 0x40);
	tmp32 |= CLKSEL_GPT9;
	out32(timer_ptr + 0x40, tmp32); // select sys clock
	munmap_device_io(timer_ptr, PG_SZ);

	// set up the timer
	timer_ptr = mmap_device_io(PG_SZ, TIMER_9_BASE);
	out32(timer_ptr + TIMER_TCLR, 0); // disable
	//out32(timer_ptr + TIMER_TLDR, tldr);
	out32(timer_ptr + TIMER_TLDR, 0xffffffe0);
	//out32(timer_ptr + TIMER_TMAR, tmar);
	out32(timer_ptr + TIMER_TMAR, 0xffffffef);
	//out32(timer_ptr + TIMER_TCCR, tldr);
	out32(timer_ptr + TIMER_TCCR, 0xffffffe0);
	tmp32 = TIMER_START | TIMER_AUTORELOAD | TIMER_PT | TIMER_TRG | TIMER_CE | TIMER_SCPWM;
	out32(timer_ptr + TIMER_TCLR, tmp32);

	signal(SIGINT, sighandler);
	signal(SIGTERM, sighandler);
	while (keep_running) {
		printf("%x\n", in32(timer_ptr + TIMER_TCCR));
		sleep(1);
	}
	// clean up
	munmap_device_io(timer_ptr, PG_SZ);
	return EXIT_SUCCESS;
}