
#define LARGER_NAND_PAGE

#define GSTATUS1        (*(volatile unsigned int *)0x560000B0)
#define BUSY            1

#define NAND_SECTOR_SIZE    512
#define NAND_BLOCK_MASK     (NAND_SECTOR_SIZE - 1)

#define NAND_SECTOR_SIZE_LP    2048
#define NAND_BLOCK_MASK_LP     (NAND_SECTOR_SIZE_LP - 1)

typedef unsigned int S3C24X0_REG32;


/* NAND FLASH (see S3C2410 manual chapter 6) */
typedef struct {
    S3C24X0_REG32   NFCONF;
    S3C24X0_REG32   NFCMD;
    S3C24X0_REG32   NFADDR;
    S3C24X0_REG32   NFDATA;
    S3C24X0_REG32   NFSTAT;
    S3C24X0_REG32   NFECC;
} S3C2410_NAND;

/* NAND FLASH (see S3C2440 manual chapter 6, www.100ask.net) */
typedef struct {
    S3C24X0_REG32   NFCONF;
    S3C24X0_REG32   NFCONT;
    S3C24X0_REG32   NFCMD;
    S3C24X0_REG32   NFADDR;
    S3C24X0_REG32   NFDATA;
    S3C24X0_REG32   NFMECCD0;
    S3C24X0_REG32   NFMECCD1;
    S3C24X0_REG32   NFSECCD;
    S3C24X0_REG32   NFSTAT;
    S3C24X0_REG32   NFESTAT0;
    S3C24X0_REG32   NFESTAT1;
    S3C24X0_REG32   NFMECC0;
    S3C24X0_REG32   NFMECC1;
    S3C24X0_REG32   NFSECC;
    S3C24X0_REG32   NFSBLK;
    S3C24X0_REG32   NFEBLK;
} S3C2440_NAND;


typedef struct {
    void (*nand_reset)(void);
    void (*wait_idle)(void);
    void (*nand_select_chip)(void);
    void (*nand_deselect_chip)(void);
    void (*write_cmd)(int cmd);
    void (*write_addr)(unsigned int addr);
    unsigned char (*read_data)(void);
}t_nand_chip;

static t_nand_chip nand_chip;

/* 供外部调用的函数 */
void nand_init(void);
void nand_read(unsigned char *buf, unsigned long start_addr, int size);

/* NAND Flash操作的总入口, 它们将调用S3C2410或S3C2440的相应函数 */
static void nand_reset(void);
static void wait_idle(void);
static void nand_select_chip(void);
static void nand_deselect_chip(void);
static void write_cmd(int cmd);
static void write_addr(unsigned int addr);
static unsigned char read_data(void);

/* S3C2410的NAND Flash处理函数 */
static void s3c2410_nand_reset(void);
static void s3c2410_wait_idle(void);
static void s3c2410_nand_select_chip(void);
static void s3c2410_nand_deselect_chip(void);
static void s3c2410_write_cmd(int cmd);
static void s3c2410_write_addr(unsigned int addr);
static unsigned char s3c2410_read_data();

/* S3C2440的NAND Flash处理函数 */
static void s3c2440_nand_reset(void);
static void s3c2440_wait_idle(void);
static void s3c2440_nand_select_chip(void);
static void s3c2440_nand_deselect_chip(void);
static void s3c2440_write_cmd(int cmd);
static void s3c2440_write_addr(unsigned int addr);
static unsigned char s3c2440_read_data(void);

/* S3C2410的NAND Flash操作函数 */

/* 复位 */
static void s3c2410_nand_reset(void)
{
    s3c2410_nand_select_chip();
    s3c2410_write_cmd(0xff);  // 复位命令
    s3c2410_wait_idle();
    s3c2410_nand_deselect_chip();
}

/* 等待NAND Flash就绪 */
static void s3c2410_wait_idle(void)
{
    int i;
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

    volatile unsigned char *p = (volatile unsigned char *)&s3c2410nand->NFSTAT;
    while(!(*p & BUSY))
        for(i=0; i<10; i++);
}

/* 发出片选信号 */
static void s3c2410_nand_select_chip(void)
{
    int i;
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;
	
    s3c2410nand->NFCONF &= ~(1<<11);
    for(i=0; i<10; i++);    
}

/* 取消片选信号 */
static void s3c2410_nand_deselect_chip(void)
{
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

    s3c2410nand->NFCONF |= (1<<11);
}

/* 发出命令 */
static void s3c2410_write_cmd(int cmd)
{
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

    volatile unsigned char *p = (volatile unsigned char *)&s3c2410nand->NFCMD;
    *p = cmd;
}

/* 发出地址 */
static void s3c2410_write_addr(unsigned int addr)
{
    int i;
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

    volatile unsigned char *p = (volatile unsigned char *)&s3c2410nand->NFADDR;
    
    *p = addr & 0xff;
    for(i=0; i<10; i++);
    *p = (addr >> 9) & 0xff;
    for(i=0; i<10; i++);
    *p = (addr >> 17) & 0xff;
    for(i=0; i<10; i++);
    *p = (addr >> 25) & 0xff;
    for(i=0; i<10; i++);
}

/* 读取数据 */
static unsigned char s3c2410_read_data(void)
{
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

    volatile unsigned char *p = (volatile unsigned char *)&s3c2410nand->NFDATA;
    return *p;
}

/* S3C2440的NAND Flash操作函数 */

/* 复位 */
static void s3c2440_nand_reset(void)
{
    s3c2440_nand_select_chip();
    s3c2440_write_cmd(0xff);  // 复位命令
    s3c2440_wait_idle();
    s3c2440_nand_deselect_chip();
}

/* 等待NAND Flash就绪 */
static void s3c2440_wait_idle(void)
{
    int i;
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

    volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFSTAT;
    while(!(*p & BUSY))
        for(i=0; i<10; i++);
}

/* 发出片选信号 */
static void s3c2440_nand_select_chip(void)
{
    int i;
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

    s3c2440nand->NFCONT &= ~(1<<1);
    for(i=0; i<10; i++);    
}

/* 取消片选信号 */
static void s3c2440_nand_deselect_chip(void)
{
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

    s3c2440nand->NFCONT |= (1<<1);
}

/* 发出命令 */
static void s3c2440_write_cmd(int cmd)
{
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

    volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFCMD;
    *p = cmd;
}

/* 发出地址 */
static void s3c2440_write_addr(unsigned int addr)
{
    int i;
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

    volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFADDR;
    
    *p = addr & 0xff;
    for(i=0; i<10; i++);
    *p = (addr >> 9) & 0xff;
    for(i=0; i<10; i++);
    *p = (addr >> 17) & 0xff;
    for(i=0; i<10; i++);
    *p = (addr >> 25) & 0xff;
    for(i=0; i<10; i++);
}


static void s3c2440_write_addr_lp(unsigned int addr)
{
	int i;
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

	volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFADDR;
	int col, page;

	col = addr & NAND_BLOCK_MASK_LP;
	page = addr / NAND_SECTOR_SIZE_LP;
	
	*p = col & 0xff;			/* Column Address A0~A7 */
	for(i=0; i<10; i++);		
	*p = (col >> 8) & 0x0f; 	/* Column Address A8~A11 */
	for(i=0; i<10; i++);
	*p = page & 0xff;			/* Row Address A12~A19 */
	for(i=0; i<10; i++);
	*p = (page >> 8) & 0xff;	/* Row Address A20~A27 */
	for(i=0; i<10; i++);
	*p = (page >> 16) & 0x03;	/* Row Address A28~A29 */
	for(i=0; i<10; i++);
}


/* 读取数据 */
static unsigned char s3c2440_read_data(void)
{
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

    volatile unsigned char *p = (volatile unsigned char *)&s3c2440nand->NFDATA;
    return *p;
}


/* 在第一次使用NAND Flash前，复位一下NAND Flash */
static void nand_reset(void)
{
    if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
    {
		s3c2410_nand_reset();
    }
	else
	{
		s3c2440_nand_reset();
	}
}

static void wait_idle(void)
{
    if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
    {
    	s3c2410_wait_idle();
    }
	else
	{
    	s3c2440_wait_idle();
	}
}

static void nand_select_chip(void)
{
    int i;
    if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
    {
	    s3c2410_nand_select_chip();
    }
	else
	{
	    s3c2440_nand_select_chip();
	}
    for(i=0; i<10; i++);
}

static void nand_deselect_chip(void)
{
    if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
    {
	    s3c2410_nand_deselect_chip();
    }
	else
	{
	    s3c2440_nand_deselect_chip();
	}
}

static void write_cmd(int cmd)
{
    if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
    {
	    s3c2410_write_cmd(cmd);
    }
	else
	{
	    s3c2440_write_cmd(cmd);
	}
}
static void write_addr(unsigned int addr)
{
    if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
    {
	    s3c2410_write_addr(addr);
    }
	else
	{
	    s3c2440_write_addr_lp(addr);
	}
}

static unsigned char read_data(void)
{
    if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
    {
	    return s3c2440_read_data();
    }
	else
	{
	    return s3c2440_read_data();
	}
}


/* 初始化NAND Flash */
void nand_init(void)
{
	S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
	S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

#define TACLS   0
#define TWRPH0  3
#define TWRPH1  0

    /* 判断是S3C2410还是S3C2440 */
    if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
    {
		/* 使能NAND Flash控制器, 初始化ECC, 禁止片选, 设置时序 */
        s3c2410nand->NFCONF = (1<<15)|(1<<12)|(1<<11)|(TACLS<<8)|(TWRPH0<<4)|(TWRPH1<<0);

		/* 复位NAND Flash */
		s3c2410_nand_reset();
    }
    else
    {
		/* 设置时序 */
        s3c2440nand->NFCONF = (TACLS<<12)|(TWRPH0<<8)|(TWRPH1<<4);
        /* 使能NAND Flash控制器, 初始化ECC, 禁止片选 */
        s3c2440nand->NFCONT = (1<<4)|(1<<1)|(1<<0);

		/* 复位NAND Flash */
		s3c2440_nand_reset();
    }
}


/* 读函数 */
void nand_read(unsigned char *buf, unsigned long start_addr, int size)
{
    int i, j;

    /* 选中芯片 */
    nand_select_chip();

    for(i=start_addr; i < (start_addr + size);) {
      /* 发出READ0命令 */
      write_cmd(0);

      /* Write Address */
      write_addr(i);
#ifdef LARGER_NAND_PAGE
      write_cmd(0x30);		
#endif
      wait_idle();

#ifdef LARGER_NAND_PAGE
      for(j=0; j < NAND_SECTOR_SIZE_LP; j++, i++) {
#else
	  for(j=0; j < NAND_SECTOR_SIZE; j++, i++) {
#endif
          *buf = read_data();
          buf++;
      }
    }

    /* 取消片选信号 */
    nand_deselect_chip();
    
    return ;
}

