/*  cpuctrl for GP2X
    Copyright (C) 2005  Hermes/PS2Reality 
	the gamma-routine was provided by theoddbot
	parts (c) Rlyehs Work & (C) 2006 god_at_hell 

    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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

*/


#include <sys/mman.h>
#include <math.h>
#include "cpuctrl.h"


/* system registers */
static struct 
{
	unsigned short SYSCLKENREG,SYSCSETREG,FPLLVSETREG,DUALINT920,DUALINT940,DUALCTRL940,MEMTIMEX0,MEMTIMEX1;
}
system_reg;

static unsigned short dispclockdiv;

static volatile unsigned short *MEM_REG;

#define SYS_CLK_FREQ 7372800


void cpuctrl_init(void)
{
	extern volatile unsigned short *gp2x_memregs; /* from minimal library rlyeh */
	MEM_REG=&gp2x_memregs[0];
	system_reg.SYSCSETREG=MEM_REG[0x91c>>1];
	system_reg.FPLLVSETREG=MEM_REG[0x912>>1];
	system_reg.SYSCLKENREG=MEM_REG[0x904>>1];
	system_reg.DUALINT920=MEM_REG[0x3B40>>1];
	system_reg.DUALINT940=MEM_REG[0x3B42>>1];
	system_reg.DUALCTRL940=MEM_REG[0x3B48>>1];
	system_reg.MEMTIMEX0=MEM_REG[0x3802>>1];
	system_reg.MEMTIMEX1=MEM_REG[0x3804>>1];
	dispclockdiv=MEM_REG[0x924>>1];
}


void cpuctrl_deinit(void)
{
	MEM_REG[0x91c>>1]=system_reg.SYSCSETREG;
	MEM_REG[0x910>>1]=system_reg.FPLLVSETREG;
	MEM_REG[0x3B40>>1]=system_reg.DUALINT920;
	MEM_REG[0x3B42>>1]=system_reg.DUALINT940;
	MEM_REG[0x3B48>>1]=system_reg.DUALCTRL940;
	MEM_REG[0x904>>1]=system_reg.SYSCLKENREG;
	MEM_REG[0x924>>1]=dispclockdiv;
	MEM_REG[0x3802>>1]=system_reg.MEMTIMEX0;
	MEM_REG[0x3804>>1]=system_reg.MEMTIMEX1 /*| 0x9000*/;
}


void set_display_clock_div(unsigned div)
{
	div=((div & 63) | 64)<<8;
	MEM_REG[0x924>>1]=(MEM_REG[0x924>>1] & ~(255<<8)) | div;
}


void set_FCLK(unsigned MHZ)
{
	unsigned v;
	unsigned mdiv,pdiv=3,scale=0;
	MHZ*=1000000;
	mdiv=(MHZ*pdiv)/SYS_CLK_FREQ;
	mdiv=((mdiv-8)<<8) & 0xff00;
	pdiv=((pdiv-2)<<2) & 0xfc;
	scale&=3;
	v=mdiv | pdiv | scale;
	MEM_REG[0x910>>1]=v;
}


void set_920_Div(unsigned short div)
{
	unsigned short v;
	v = MEM_REG[0x91c>>1] & (~0x3);
	MEM_REG[0x91c>>1] = (div & 0x7) | v; 
}


void set_DCLK_Div( unsigned short div )
{
	unsigned short v;
	v = (unsigned short)( MEM_REG[0x91c>>1] & (~(0x7 << 6)) );
	MEM_REG[0x91c>>1] = ((div & 0x7) << 6) | v; 
}

/*
void Disable_940(void)
{
	MEM_REG[0x3B42>>1];
	MEM_REG[0x3B42>>1]=0;
	MEM_REG[0x3B46>>1]=0xffff;	
	MEM_REG[0x3B48>>1]|= (1 << 7);
	MEM_REG[0x904>>1]&=0xfffe;
}
*/

void set_RAM_Timings(int tRC, int tRAS, int tWR, int tMRD, int tRFC, int tRP, int tRCD)
{
	tRC -= 1; tRAS -= 1; tWR -= 1; tMRD -= 1; tRFC -= 1; tRP -= 1; tRCD -= 1; // ???
	MEM_REG[0x3802>>1] = ((tMRD & 0xF) << 12) | ((tRFC & 0xF) << 8) | ((tRP & 0xF) << 4) | (tRCD & 0xF);
	MEM_REG[0x3804>>1] = /*0x9000 |*/ ((tRC & 0xF) << 8) | ((tRAS & 0xF) << 4) | (tWR & 0xF);
}


/*
void gp2x_video_wait_vsync(void)
{
	MEM_REG[0x2846>>1]=(MEM_REG[0x2846>>1] | 0x20) & ~2;
	while(!(MEM_REG[0x2846>>1] & 2));
}
*/

void set_gamma(int g100)
{
	float gamma = (float) g100 / 100;
	int i;
	//printf ("set gamma = %f\r\n",gamma);
	gamma = 1/gamma;

    //enable gamma
    MEM_REG[0x2880>>1]&=~(1<<12);

    MEM_REG[0x295C>>1]=0;
    for(i=0; i<256; i++)
    {
		unsigned char g;
        unsigned short s;
        g =(unsigned char)(255.0*pow(i/255.0,gamma));
        s = (g<<8) | g;
		MEM_REG[0x295E>>1]= s;
        MEM_REG[0x295E>>1]= g;
    }
}