#include "def.h"
#include "2410addr.h"
#include "2410lib.h"


#define	BLK_IDXL	8
#define	BLK_IDXH	9
#define	FMT_TAG		15

char format_tags[] = "Formatted For NAND FLASH Driver";	//must be less than 32
/***********************************************************/
//nand ecc utils
typedef	unsigned char u_char;
static u_char eccpos[6] = {0, 1, 2, 3, 6, 7};

/*
 * Pre-calculated 256-way 1 byte column parity
 */
static const u_char nand_ecc_precalc_table[] = {
	0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00,
	0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
	0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
	0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
	0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
	0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
	0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
	0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
	0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,
	0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,
	0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,
	0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,
	0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,
	0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,
	0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,
	0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00
};


/**
 * nand_trans_result - [GENERIC] create non-inverted ECC
 * @reg2:	line parity reg 2
 * @reg3:	line parity reg 3
 * @ecc_code:	ecc 
 *
 * Creates non-inverted ECC code from line parity
 */
static void nand_trans_result(u_char reg2, u_char reg3,
	u_char *ecc_code)
{
	u_char a, b, i, tmp1, tmp2;
	
	/* Initialize variables */
	a = b = 0x80;
	tmp1 = tmp2 = 0;
	
	/* Calculate first ECC byte */
	for (i = 0; i < 4; i++) {
		if (reg3 & a)		/* LP15,13,11,9 --> ecc_code[0] */
			tmp1 |= b;
		b >>= 1;
		if (reg2 & a)		/* LP14,12,10,8 --> ecc_code[0] */
			tmp1 |= b;
		b >>= 1;
		a >>= 1;
	}
	
	/* Calculate second ECC byte */
	b = 0x80;
	for (i = 0; i < 4; i++) {
		if (reg3 & a)		/* LP7,5,3,1 --> ecc_code[1] */
			tmp2 |= b;
		b >>= 1;
		if (reg2 & a)		/* LP6,4,2,0 --> ecc_code[1] */
			tmp2 |= b;
		b >>= 1;
		a >>= 1;
	}
	
	/* Store two of the ECC bytes */
	ecc_code[0] = tmp1;
	ecc_code[1] = tmp2;
}

/**
 * nand_calculate_ecc - [NAND Interface] Calculate 3 byte ECC code for 256 byte block
 * @dat:	raw data
 * @ecc_code:	buffer for ECC
 */
int nand_calculate_ecc(const u_char *dat, u_char *ecc_code)
{
	u_char idx, reg1, reg2, reg3;
	int j;
	
	/* Initialize variables */
	reg1 = reg2 = reg3 = 0;
	ecc_code[0] = ecc_code[1] = ecc_code[2] = 0;
	
	/* Build up column parity */ 
	for(j = 0; j < 256; j++) {
		
		/* Get CP0 - CP5 from table */
		idx = nand_ecc_precalc_table[dat[j]];
		reg1 ^= (idx & 0x3f);
		
		/* All bit XOR = 1 ? */
		if (idx & 0x40) {
			reg3 ^= (u_char) j;
			reg2 ^= ~((u_char) j);
		}
	}
	
	/* Create non-inverted ECC code from line parity */
	nand_trans_result(reg2, reg3, ecc_code);
	
	/* Calculate final ECC code */
	ecc_code[0] = ~ecc_code[0];
	ecc_code[1] = ~ecc_code[1];
	ecc_code[2] = ((~reg1) << 2) | 0x03;
	return 0;
}

/**
 * nand_correct_data - [NAND Interface] Detect and correct bit error(s)
 * @dat:	raw data read from the chip
 * @read_ecc:	ECC from the chip
 * @calc_ecc:	the ECC calculated from raw data
 *
 * Detect and correct a 1 bit error for 256 byte block
 */
int nand_correct_data(u_char *dat, u_char *read_ecc, u_char *calc_ecc)
{
	u_char a, b, c, d1, d2, d3, add, bit, i;
	
	/* Do error detection */ 
	d1 = calc_ecc[0] ^ read_ecc[0];
	d2 = calc_ecc[1] ^ read_ecc[1];
	d3 = calc_ecc[2] ^ read_ecc[2];
	
	if ((d1 | d2 | d3) == 0) {
		/* No errors */
		return 0;
	}
	else {
		a = (d1 ^ (d1 >> 1)) & 0x55;
		b = (d2 ^ (d2 >> 1)) & 0x55;
		c = (d3 ^ (d3 >> 1)) & 0x54;
		
		/* Found and will correct single bit error in the data */
		if ((a == 0x55) && (b == 0x55) && (c == 0x54)) {
			c = 0x80;
			add = 0;
			a = 0x80;
			for (i=0; i<4; i++) {
				if (d1 & c)
					add |= a;
				c >>= 2;
				a >>= 1;
			}
			c = 0x80;
			for (i=0; i<4; i++) {
				if (d2 & c)
					add |= a;
				c >>= 2;
				a >>= 1;
			}
			bit = 0;
			b = 0x04;
			c = 0x80;
			for (i=0; i<3; i++) {
				if (d3 & c)
					bit |= b;
				c >>= 2;
				b >>= 1;
			}
			b = 0x01;
			a = dat[add];
			a ^= (b << bit);
			dat[add] = a;
			return 1;
		}
		else {
			i = 0;
			while (d1) {
				if (d1 & 0x01)
					++i;
				d1 >>= 1;
			}
			while (d2) {
				if (d2 & 0x01)
					++i;
				d2 >>= 1;
			}
			while (d3) {
				if (d3 & 0x01)
					++i;
				d3 >>= 1;
			}
			if (i == 1) {
				/* ECC Code Error Correction */
				read_ecc[0] = calc_ecc[0];
				read_ecc[1] = calc_ecc[1];
				read_ecc[2] = calc_ecc[2];
				return 2;
			}
			else {
				/* Uncorrectable Error */
				return -1;
			}
		}
	}
	
	/* Should never happen */
	return -1;
}


#define	EnNandFlash()	(rNFCONF |= 0x8000)
#define	DsNandFlash()	(rNFCONF &= ~0x8000)
#define	InitEcc()		(rNFCONF |= 0x1000)
#define	NoEcc()			(rNFCONF &= ~0x1000)
#define	NFChipEn()		(rNFCONF &= ~0x800)
#define	NFChipDs()		(rNFCONF |= 0x800)

#define	WrNFCmd(cmd)	(rNFCMD = (cmd))
#define	WrNFAddr(addr)	(rNFADDR = (addr))
#define	WrNFDat(dat)	(rNFDATA = (dat))
#define	RdNFDat()		(rNFDATA)
#define	RdNFStat()		(rNFSTAT)
#define	NFIsBusy()		(!(rNFSTAT&1))
#define	NFIsReady()		(rNFSTAT&1)

//#define	WIAT_BUSY_HARD	1
//#define	ER_BAD_BLK_TEST
//#define	WR_BAD_BLK_TEST

#define	READCMD0	0
#define	READCMD1	1
#define	READCMD2	0x50
#define	ERASECMD0	0x60
#define	ERASECMD1	0xd0
#define	PROGCMD0	0x80
#define	PROGCMD1	0x10
#define	QUERYCMD	0x70
#define	RdIDCMD		0x90

static U16 NandAddr;


static void InitNandCfg(void)
{
	//enable nand flash control, initilize ecc, chip disable,
	rNFCONF = (1<<15)|(1<<12)|(1<<11)|(7<<8)|(7<<4)|(7);	
}

#ifdef	WIAT_BUSY_HARD
#define	WaitNFBusy()	while(NFIsBusy())
#else
static U32 WaitNFBusy(void)	// R/B 未接好?
{
	U8 stat;
	
	WrNFCmd(QUERYCMD);
	do {
		stat = RdNFDat();
		//printf("%x\n", stat);
	}while(!(stat&0x40));
	WrNFCmd(READCMD0);
	return stat&1;
}
#endif

static U32 ReadChipId(void)
{
	U32 id;
	
	NFChipEn();	
	WrNFCmd(RdIDCMD);
	WrNFAddr(0);
	while(NFIsBusy());	
	id  = RdNFDat()<<8;
	id |= RdNFDat();		
	NFChipDs();		
	
	return id;
}

static U16 ReadStatus(void)
{
	U16 stat;
	
	NFChipEn();	
	WrNFCmd(QUERYCMD);		
	stat = RdNFDat();	
	NFChipDs();
	
	return stat;
}

static U32 EraseBlock(U32 addr)
{
	U8 stat;

	addr &= ~0x1f;
		
	NFChipEn();	
	WrNFCmd(ERASECMD0);		
	WrNFAddr(addr);
	WrNFAddr(addr>>8);
	if(NandAddr)
		WrNFAddr(addr>>16);
	WrNFCmd(ERASECMD1);		
	stat = WaitNFBusy();
	NFChipDs();
	
#ifdef	ER_BAD_BLK_TEST
	if(!((addr+0xe0)&0xff)) stat = 1;	//just for test bad block
#endif
	
	//printf("Erase block 0x%x %s\n", addr, stat?"fail":"ok");
	putch('.');
	return stat;
}

//addr = page address
static void ReadPage(U32 addr, U8 *buf)
{
	U16 i;
	
	NFChipEn();
	WrNFCmd(READCMD0);
	WrNFAddr(0);
	WrNFAddr(addr);
	WrNFAddr(addr>>8);
	if(NandAddr)
		WrNFAddr(addr>>16);
	InitEcc();
	WaitNFBusy();
	for(i=0; i<512; i++)
		buf[i] = RdNFDat();
	NFChipDs();
}

static U32 WritePage(U32 addr, U8 *buf, U16 blk_idx)
{
	U16 i;
	U8 stat;
	U8 ecc_code[3];
	U8 oob_info[16];
		
	for(i=0; i<sizeof(oob_info); i++)
		oob_info[i] = 0xff;
	
	nand_calculate_ecc(buf, ecc_code);
	oob_info[eccpos[0]] = ecc_code[0];
	oob_info[eccpos[1]] = ecc_code[1];
	oob_info[eccpos[2]] = ecc_code[2];
	nand_calculate_ecc(buf+256, ecc_code);
	oob_info[eccpos[3]] = ecc_code[0];
	oob_info[eccpos[4]] = ecc_code[1];
	oob_info[eccpos[5]] = ecc_code[2];
	oob_info[BLK_IDXL]  = blk_idx;
	oob_info[BLK_IDXH]  = blk_idx>>8;
	oob_info[FMT_TAG]   = format_tags[addr&0x1f];
	
	NFChipEn();
	WrNFCmd(PROGCMD0);
	WrNFAddr(0);
	WrNFAddr(addr);
	WrNFAddr(addr>>8);
	if(NandAddr)
		WrNFAddr(addr>>16);
//	InitEcc();	
	for(i=0; i<512; i++)
		WrNFDat(buf[i]);
		
	if(!addr) {
		WrNFDat('b');
		WrNFDat('o');
		WrNFDat('o');
		WrNFDat('t');		
	} else {		
		for(i=0; i<sizeof(oob_info); i++)
			WrNFDat(oob_info[i]);
	}
/*	tmp[0] = rNFECC0;
    tmp[1] = rNFECC1;
    tmp[2] = rNFECC2;
    	
	WrNFDat(tmp[0]);
	WrNFDat(tmp[1]);
	WrNFDat(tmp[2]);
*/		
	WrNFCmd(PROGCMD1);
	stat = WaitNFBusy();
	NFChipDs();
	
#ifdef	WR_BAD_BLK_TEST
	if((addr&0xff)==0x17) stat = 1;	//just for test bad block
#endif
		
	if(stat)
		printf("Write nand flash 0x%x fail\n", addr);
	else {	
		U8 RdDat[512];
		
		ReadPage(addr, RdDat);		
		for(i=0; i<512; i++)
			if(RdDat[i]!=buf[i]) {
				printf("Check data at page 0x%x, offset 0x%x fail\n", addr, i);
				stat = 1;
				break;
			}
	}
		
	return stat;	
}

static void MarkBadBlk(U32 addr)
{
	addr &= ~0x1f;
	
	NFChipEn();
	
	WrNFCmd(READCMD2);	//point to area c
	
	WrNFCmd(PROGCMD0);
	WrNFAddr(4);		//mark offset 4,5,6,7
	WrNFAddr(addr);
	WrNFAddr(addr>>8);
	if(NandAddr)
		WrNFAddr(addr>>16);
	WrNFDat(0);			//mark with 0
	WrNFDat(0);
	WrNFDat(0);			//mark with 0
	WrNFDat(0);
	WrNFCmd(PROGCMD1);
	WaitNFBusy();		//needn't check return status
	
	WrNFCmd(READCMD0);	//point to area a
		
	NFChipDs();
}

static int CheckBadBlk(U32 addr)
{
	U8 dat;