#include	"u.h"
#include	"../port/lib.h"
#include	"mem.h"
#include	"dat.h"
#include	"fns.h"
#include	"io.h"

#include	"ureg.h"

/*
 * jz4780 timer/counter unit
 */

#define TER	0x10
#define TESR	0x14
#define TECR	0x18
#define	TFR	0x20
#define TFCR	0x28
#define TMCR	0x38
#define TCSR0	0x4C

#define TDFR5	0x90
#define	TDHR5	0x94
#define	TCNT5	0x98
#define TCSR5	0x9C

/* operating system timer */
#define OSTDR	0xE0
#define OSTCNTL	0xE4
#define OSTCNTH 0xE8
#define OSTCSR	0xEC
#define	OSTBUF	0xFC

enum
{
	/* hz */
	RTCCLK	= 32768,
};

/* initialize system clocks */
void
clockinit(void)
{
	m->maxperiod = 1024;
	m->minperiod = 2;

	/* reset counter */
	*IO(u32int, TCUBASE+OSTCNTL) = 0;
	*IO(u32int, TCUBASE+OSTCNTH) = 0;

	/* no clear on overflow, CLK/16, RTCCLK */
	*IO(u16int, TCUBASE+OSTCSR) = (1<<15) | (1<<4) | (1<<1);

	/* ~500 ms */
	*IO(u32int, TCUBASE+OSTDR) = m->maxperiod;

	/* enable os timer  */
	*IO(u16int, TCUBASE+TESR) = (1<<15);

	/* clear os timer mask */
	*IO(u32int, TCUBASE+TMCR) = (1<<15);

	intrenable(IRQTCU0, clock, nil);
}

void
clock(Ureg *ur, void*)
{
	*IO(u32int, TCUBASE+OSTDR) = *IO(u32int, TCUBASE+OSTCNTL) + m->maxperiod;

	/* clear comparison flag */
	*IO(u32int, TCUBASE+TFCR) = (1<<15);

	timerintr(ur, 0);
}

void
microdelay(int n)
{
	ulong now;
	now = µs();
	while(µs() - now < n);
}

void
delay(int ms)
{
	while(--ms >= 0)
		microdelay(1000);
}

ulong
µs(void)
{
	return fastticks2us(fastticks(nil));
}

uvlong
fastticks(uvlong *hz)
{
	int x;
	ulong delta, count;

	if(hz)
		*hz = RTCCLK/16;

	/* avoid reentry on interrupt or trap, to prevent recursion */
	x = splhi();
	count = *IO(u32int, TCUBASE+OSTCNTL);
	if(*IO(u32int, TCUBASE+OSTDR) - count > m->maxperiod)
		*IO(u32int, TCUBASE+OSTDR) = count + m->maxperiod;
	if (count < m->lastcount)		/* wrapped around? */
		delta = count + ((1ull<<32) - m->lastcount);
	else
		delta = count - m->lastcount;
	m->lastcount = count;
	m->fastticks += delta;
	splx(x);

	return m->fastticks;
}

ulong
perfticks(void)
{
	return *IO(ulong, TCUBASE+OSTCNTL);
}

void
timerset(Tval next)
{
	int x;
	long period;

	if(next == 0)
		return;

	/* don't let us get scheduled */
	x = splhi();

	period = next - fastticks(nil);

	if(period > m->maxperiod - m->minperiod)
		period = m->maxperiod;
	else if(period < m->minperiod)
		period = m->minperiod;

	*IO(u32int, TCUBASE+OSTDR) = period;

	splx(x);
}