#include "asm/types.h"
#include "asm/io.h"

#include "sound.h"

/* send MONO as a stereo signal, to get the same output power to the speakers */
#define MONO_AS_STEREO

/* some sound defines */
#define SOUND_VOL(n)		(n)
/* NOTE: you have to write the timer value calculation THIS way.
   To avoid strange results (if you use a negative hex number). */
#define SOUND_FREQ(n)		(0 - (0x1000000 / (n)))
#define SOUND_ENABLE		(1<<15)
#define SOUND_REPEAT		(1<<27)
#define SOUND_ONE_SHOT		(1<<28)
#define SOUND_FORMAT_8BIT	(0<<29)
#define SOUND_FORMAT_16BIT	(1<<29)
#define SOUND_FORMAT_ADPCM	(2<<29)
#define SOUND_FORMAT_PSG	(3<<29)
#define SCHANNEL_ENABLE		(1<<31)

#define SCHANNEL_TIMER(n)	(*(volatile u16*)(0x04000408 + ((n)<<4)))
#define SCHANNEL_CR(n)		(*(volatile u32*)(0x04000400 + ((n)<<4)))
#define SCHANNEL_VOL(n)		(0x04000400 + ((n)<<4))
#define SCHANNEL_PAN(n)		(0x04000402 + ((n)<<4))
#define SCHANNEL_SOURCE(n)	(*(volatile u32*)(0x04000404 + ((n)<<4)))
#define SCHANNEL_REPEAT_POINT(n) (*(volatile u16*)(0x0400040A + ((n)<<4)))
#define SCHANNEL_LENGTH(n)	(*(volatile u32*)(0x0400040C + ((n)<<4)))
#define SOUND_CR		(*(volatile u16*)0x04000500)
#define POWER_CR		(*(volatile u16*)0x04000304)

static u32 s_channels;
static u32 true_channels;
static u32 s_format;
static u32 s_size;

/* Plays sounds from the specified buffer */
void sound_play(void)
{
	u8 i;

	for (i = 0; i < s_channels; i++) {
		SCHANNEL_CR(i) = SCHANNEL_ENABLE | SOUND_REPEAT | s_format;
		writeb(SOUND_VOL(127), SCHANNEL_VOL(i));
		writeb(((i % 2) ? 127 : 0), SCHANNEL_PAN(i));
		SCHANNEL_REPEAT_POINT(i) = 0;
	}

	if (s_channels == 1) {
		writeb(64, SCHANNEL_PAN(0));
	}

	sound_set_master_volume(127);
}

void sound_stop(void)
{
	u8 i;

	for (i = 0; i < s_channels; i++)
		SCHANNEL_CR(i) = 0;
}

void sound_set_rate(u32 rate)
{
	u8 i;

	for (i = 0; i < s_channels; i++)
		SCHANNEL_TIMER(i) = SOUND_FREQ(rate);
}

void sound_set_address(u32 buffer)
{
	u8 i;

	for (i = 0; i < s_channels; i++)
		SCHANNEL_SOURCE(i) = buffer + i * (s_size / s_channels);
#ifdef MONO_AS_STEREO
	if (true_channels == 1)
		SCHANNEL_SOURCE(1) = buffer;
#endif
}

void sound_set_size(u32 size)
{
	u8 i;

	s_size = size;
	for (i = 0; i < s_channels; i++)
		SCHANNEL_LENGTH(i) = (s_size / true_channels) >> 2;
}

void sound_set_channels(u8 channels)
{
	true_channels = channels;
#ifdef MONO_AS_STEREO
	if (channels & 1)
		channels++;
#endif
	s_channels = channels;
}

void sound_set_format(u8 format)
{
	s_format = format << 29;
}

/* set the master volume */
void sound_set_master_volume(u8 vol)
{
	SOUND_CR = SOUND_ENABLE | SOUND_VOL(vol);
}

/* Turn on/off sound 1 = on 0 = off */
void sound_set_power(u8 state)
{
	if (state) {
		POWER_CR |= 1;
		SOUND_CR = SOUND_ENABLE;
	} else {
		//POWER_CR &= ~1;
		SOUND_CR = 0;
	}
}