/*
 * http://ghmicro.com/index.php/pic/13-18f4620/11-18f4620-a-sd-card
 */

#include <system.h>
#include <memory.h>
#include "sdcard.h"
#include "spi.h"

char sd_output_buffer1[256];
char sd_output_buffer2[256];
char sd_input_buffer1[256];
char sd_input_buffer2[256];

void sd_init(void){
	int i,r;
	CSel=1;				//init chip select (active low)
	SD_LED=0;				//LED off

	for(i=0; i<256 ;i++){		//fill the send buffers
		sd_output_buffer1[i]=0;
		sd_output_buffer2[i]=0;
		sd_input_buffer1[i]=0;		//and clear the receive buffers
		sd_input_buffer2[i]=0;
	}
	r = sd_initMedia();
	if(r){				//card init failed - 1 blink
		while(1){
			SD_LED = 1;
			delay_ms(150);
			SD_LED = 0;
			delay_s(1);
		}
	}
}

int sd_initMedia(void){
	int i,r;
	CSel = 1; 
	spi_putc(0xff);		//while card is not selected
	
	for(i=0;i<16;i++)				//send 80 clock cycles to start up
		spi_putc(0xff);
	CSel = 0;						//then select the card
	r = sd_sendCmd(0,0);				//send reset command to enter SPI mode
	
	CSel = 1; 
	spi_putc(0xff);		//disable SD
	if(r != 1)						//error check - need 1
		return 0x84;
	
	i = 10000;						//send init for up to 0.3s
	CSel = 0;
	do{
		r = sd_sendCmd(1,0);			//send init command
		CSel = 1; 
		spi_putc(0xff);	//disable SD
		if(!r) break;
	}while(--i > 0);
	
	if(i==0)						//time out error 0x85
		return 0x85;
	sspcon1 = 0b00010000;			//speed up spi clock
	sspcon1.SSPEN = 1;
	return 0;
}

int sd_writeSector(LBA a, char *p1, char *p2){
	unsigned r,i;
	SD_LED = 1;					//turn on write LED
	r = sd_sendCmd(24,(a<<9));
	if(r == 0){
		spi_putc(0xfe);			//send Data Start byte
		for(i=0;i<256;i++)		//first 256 bytes
			spi_putc(*p1++);
		for(i=0;i<256;i++)		//second 256 bytes
			spi_putc(*p2++);
		spi_putc(0xff);			//send dummy CRC
		spi_putc(0xff);
		if((r=spi_putc(0xff) & 0x0f) == 0x05){	//check if data accepted
			for(i=10000;i>0;i--){
				if(r=spi_putc(0xff))
					break;
			}
		}
		else
			r=0;			//fail
	}
	CSel = 1; spi_putc(0xff);			//disable SD
	SD_LED = 0;				//LED off
	return(r);
}

int sd_readSector(LBA a, char *p1, char *p2){
	int r,i;
	SD_LED = 1;				//turn on read LED
	r = sd_sendCmd(17,(a<<9));
	if(r == 0){				//check if command was accepted
		i=10000;			//wait for a response
		do{
			r = spi_putc(0xff);
			if(r==0xfe)
				break;
		}while(--i > 0);
		if(i){				//if no timeout, read 512 byte sector
			for(i=0;i<256;i++)
				*p1++ = spi_putc(0xff);
			for(i=0;i<256;i++)
				*p2++ = spi_putc(0xff);
			spi_putc(0xff);		//ignore CRC
			spi_putc(0xff);
		}
	}
	CSel = 1;spi_putc(0xff);			//disable SD
	SD_LED = 0;				//read LED off
	return(r == 0xfe);
}

int sd_sendCmd(unsigned char c, LBA a){
	int i,r;
	CSel = 0;					//send command packet (6 bytes)
	spi_putc(c|0x40);			//send command & frame bit
	spi_putc(a>>24);			//send 32-bit address
	spi_putc(a>>16);
	spi_putc(a>>8);
	spi_putc(a);
	spi_putc(0x95);				//send CRC
	i = 9;					//wait for response
	do{
		r = spi_putc(0xff);		//check if ready
		if(r != 0xff)
			break;
	}while(--i > 0);
	return(r);
}

/*
 void main(void){
	LBA addr;
	int i,r;
	trisd=0;
	trisc=0b00010000;
	CSel=1;				//init chip select (active low)
	LED=0;				//LED off
	osccon=0x72;			//8MHz clock
	osctune.6=0;			//disable PLL
	while(!osccon.IOFS);		//wait for osc stable
	sspstat = 0b00000000;		//SMP(7)=0, CKE(6)=0 (clock edge idle to active)
	sspcon1 = 0b00010010;		//CKP(4)=1 clock polarity (idle high)
					//SSPM3:SSPM0(3:0)=010 spi clock FOSC/64 (<400kHz)
	sspcon1.SSPEN=1;		//SSPEN(5)=1 enable SPI
	for(i=0;i<256;i++){		//fill the send buffers
		data1[i]=i;
		data2[i]=i;
		buffer1[i]=0;		//and clear the receive buffers
		buffer2[i]=0;
	}
	r=initMedia();
	if(r){				//card init failed - 1 blink
		while(1){
			LED=1;
			delay_ms(150);
			LED=0;
			delay_s(1);
		}
	}
	else{				//write card
		addr = 10000;
		for(i=0;i<1000;i++){
			if(!writeSector(addr+i,data1,data2)){
				while(1){		//write failed - 2 blinks
					LED=1;
					delay_ms(150);
					LED=0;
					delay_ms(150);
					LED=1;
					delay_ms(150);
					LED=0;
					delay_s(1);
				}
			}
		}
		addr=10000;			//verify write
		for(i=0;i<1000;i++){
			if(!readSector(addr+i,buffer1,buffer2)){
				while(1){		//verify failed - 3 blinks
					LED=1;
					delay_ms(150);
					LED=0;
					delay_ms(150);
					LED=1;
					delay_ms(150);
					LED=0;
					delay_ms(150);
					LED=1;
					delay_ms(150);
					LED=0;
					delay_s(1);
				}
			}

			//verify
			if(memcmp(data1,buffer1,256)||memcmp(data2,buffer2,256)){
				while(1){		//mismatch - 4 blinks
					LED=1;
					delay_ms(150);
					LED=0;
					delay_ms(150);
					LED=1;
					delay_ms(150);
					LED=0;
					delay_ms(150);
					LED=1;
					delay_ms(150);
					LED=0;
					delay_ms(150);
					LED=1;
					delay_ms(150);
					LED=0;
					delay_s(1);
				}
			}
		}
	}
	while(1){					//success!
		LED=1;
		delay_s(1);
		LED=0;
		delay_s(1);
	}
} 
*/