TQ2440 学习笔记—— 20、NAND Flash 控制器

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TQ2440 学习笔记—— 20、NAND Flash 控制器

2019-07-13 02:57发布生成海报

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（韦东山——嵌入式Linux 应用开发完全手册）一、NAND Flash控制器 1、地址空间 SRAM，DM9000 的地址总线接到了S3C2440的地址总线上；而NAND Flash 没有地址总线，与前者相比它的寻址方式是不同的。故必须分清楚地址。 2、NAND 的编址 3、NAND 的命令 4、使用S3C2440 的NAND　Flash 控制器访问NAND Flash 从硬件上： 1、发出命令 CLE DATA BUS 2、Addr ALE DATA BUS 3、传输数据 S3C2440： 1、命令寄存器 NFCMMD
2、地址寄存器 NFADDR
3、数据寄存器 NFDATA 4、状态寄存器 NFSTAT
二、源码分析

#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 S3C2410_NAND * s3c2410nand = (S3C2410_NAND *)0x4e000000;
static S3C2440_NAND * s3c2440nand = (S3C2440_NAND *)0x4e000000;

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;
    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;
    s3c2410nand->NFCONF &= ~(1<<11);
    for(i=0; i<10; i++);    
}

/* 取消片选信号 */
static void s3c2410_nand_deselect_chip(void)
{
    s3c2410nand->NFCONF |= (1<<11);
}

/* 发出命令 */
static void s3c2410_write_cmd(int cmd)
{
    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;
    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)
{
    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;
    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;
    s3c2440nand->NFCONT &= ~(1<<1);
    for(i=0; i<10; i++);    
}

/* 取消片选信号 */
static void s3c2440_nand_deselect_chip(void)
{
    s3c2440nand->NFCONT |= (1<<1);
}

/* 发出命令 */
static void s3c2440_write_cmd(int cmd)
{
    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;
    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;
	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        0 */
	for(i=0; i<10; i++);		
	*p = (col >> 8) & 0x0f; 	/* Column Address A8~A11   0 */
	for(i=0; i<10; i++);
	*p = page & 0xff;			/* Row Address A12~A19         2 */
	for(i=0; i<10; i++);
	*p = (page >> 8) & 0xff;	/* Row Address A20~A27     0 */
	for(i=0; i<10; i++);
	*p = (page >> 16) & 0x03;	/* Row Address A28~A29     0 */
	for(i=0; i<10; i++);
}


/* 读取数据 */
static unsigned char s3c2440_read_data(void)
{
    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)
{
    nand_chip.nand_reset();
}

static void wait_idle(void)
{
    nand_chip.wait_idle();
}

static void nand_select_chip(void)
{
    int i;
    nand_chip.nand_select_chip();
    for(i=0; i<10; i++);
}

static void nand_deselect_chip(void)
{
    nand_chip.nand_deselect_chip();
}

static void write_cmd(int cmd)
{
    nand_chip.write_cmd(cmd);
}
static void write_addr(unsigned int addr)
{
    nand_chip.write_addr(addr);
}

static unsigned char read_data(void)
{
    return nand_chip.read_data();
}


/* 初始化NAND Flash */
void nand_init(void)
{
#define TACLS   0
#define TWRPH0  3
#define TWRPH1  0

    /* 判断是S3C2410还是S3C2440 */
    if ((GSTATUS1 == 0x32410000) || (GSTATUS1 == 0x32410002))
    {
        nand_chip.nand_reset         = s3c2410_nand_reset;
        nand_chip.wait_idle          = s3c2410_wait_idle;
        nand_chip.nand_select_chip   = s3c2410_nand_select_chip;
        nand_chip.nand_deselect_chip = s3c2410_nand_deselect_chip;
        nand_chip.write_cmd          = s3c2410_write_cmd;
        nand_chip.write_addr         = s3c2410_write_addr;
        nand_chip.read_data          = s3c2410_read_data;

		/* 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);
    }
    else
    {
        nand_chip.nand_reset         = s3c2440_nand_reset;
        nand_chip.wait_idle          = s3c2440_wait_idle;
        nand_chip.nand_select_chip   = s3c2440_nand_select_chip;
        nand_chip.nand_deselect_chip = s3c2440_nand_deselect_chip;
        nand_chip.write_cmd          = s3c2440_write_cmd;
#ifdef LARGER_NAND_PAGE
        nand_chip.write_addr         = s3c2440_write_addr_lp;
#else
		nand_chip.write_addr		 = s3c2440_write_addr;
#endif
        nand_chip.read_data          = s3c2440_read_data;

		/* 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 */
    nand_reset();
}


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

#ifdef LARGER_NAND_PAGE
    if ((start_addr & NAND_BLOCK_MASK_LP) || (size & NAND_BLOCK_MASK_LP)) {
        return ;    /* 地址或长度不对齐 */
    }
#else
    if ((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK)) {
        return ;    /* 地址或长度不对齐 */
    }
#endif	

    /* 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 ;
}

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TQ2440 学习笔记—— 20、NAND Flash 控制器
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