Linux学习 ： 裸板调试 之 配置使用NAND FLASH

关于NAND FLASH的结构是以页为单位写，以块为单位来擦除：

1Gb     为大页   page=2048Kb    BLOCK=128K

512Mb 为小页   page=512byte    BLOCK=16K

PS:一页还有额外64字节OOB块，通常不计入读取范围。

另一个区别就是ECC的验证:

ECC是每256个字节生产一个24位的值。NAND FLASH在写的时候会生成一个原始的ECC值保存在页的SPARE区，当要读页时也会生产一个ECC值，会跟SPARE的值进行异或比较，看结果是否为0，所有在大页换小页的时候，一定要修改这个算法，相反也是大页需要8对ECC 小页只需要2对ECC。

 

实验平台:s3c2440 , Nand Flash Size:256M

1、Nand Flash 控制代码部分：nand.c

#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) */
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=; i<; i++);
}

/* 发出片选信号 */
static void s3c2410_nand_select_chip(void)
{
    int i;
    s3c2410nand->NFCONF &= ~(<<);
    for(i=; i<; i++);
}

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

/* 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=; i<; i++);
    *p = (addr >> ) & 0xff;
    for(i=; i<; i++);
    *p = (addr >> ) & 0xff;
    for(i=; i<; i++);
    *p = (addr >> ) & 0xff;
    for(i=; i<; 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=; i<; i++);
}

/* 发出片选信号 */
static void s3c2440_nand_select_chip(void)
{
    int i;
    s3c2440nand->NFCONT &= ~(<<);
    for(i=; i<; i++);
}

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

/* 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=; i<; i++);
    *p = (addr >> ) & 0xff;
    for(i=; i<; i++);
    *p = (addr >> ) & 0xff;
    for(i=; i<; i++);
    *p = (addr >> ) & 0xff;
    for(i=; i<; 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 */
    for(i=; i<; i++);
    *p = (col >> ) & 0x0f;     /* Column Address A8~A11 */
    for(i=; i<; i++);
    *p = page & 0xff;            /* Row Address A12~A19 */
    for(i=; i<; i++);
    *p = (page >> ) & 0xff;    /* Row Address A20~A27 */
    for(i=; i<; i++);
    *p = (page >> ) & 0x03;    /* Row Address A28~A29 */
    for(i=; i<; 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=; i<; 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 = (<<)|(<<)|(<<)|(TACLS<<)|(TWRPH0<<)|(TWRPH1<<);
    }
    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<<)|(TWRPH0<<)|(TWRPH1<<);
        /* 使能NAND Flash控制器, 初始化ECC, 禁止片选 */
        s3c2440nand->NFCONT = (<<)|(<<)|(<<);
    }

    /* 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();

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

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

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

    return ;
}

2、初始化SDRAM: init.c

/* WOTCH DOG register */
#define     WTCON                (*(volatile unsigned long *)0x53000000)

/* SDRAM regisers */
#define     MEM_CTL_BASE        0x48000000

void disable_watch_dog();
void memsetup();

/*上电后，WATCH DOG默认是开着的，要把它关掉 */
void disable_watch_dog()
{
    WTCON    = ;
}

/* 设置控制SDRAM的13个寄存器 */
void memsetup()
{
    int     i = ;
    unsigned long *p = (unsigned long *)MEM_CTL_BASE;

    /* SDRAM 13个寄存器的值 */
    unsigned long  const    mem_cfg_val[]={ 0x22011110,     //BWSCON
                                            0x00000700,     //BANKCON0
                                            0x00000700,     //BANKCON1
                                            0x00000700,     //BANKCON2
                                            0x00000700,     //BANKCON3
                                            0x00000700,     //BANKCON4
                                            0x00000700,     //BANKCON5
                                            0x00018005,     //BANKCON6
                                            0x00018005,     //BANKCON7
                                            0x008C07A3,     //REFRESH
                                            0x000000B1,     //BANKSIZE
                                            0x00000030,     //MRSRB6
                                            0x00000030,     //MRSRB7
                                    };

    for(; i < ; i++)
        p[i] = mem_cfg_val[i];
}

3、led操作: main.c

#define    GPFCON        (*(volatile unsigned long *)0x56000050)
#define    GPFDAT        (*(volatile unsigned long *)0x56000054)

#define    GPF4_out    (1<<(4*2))
#define    GPF5_out    (1<<(5*2))
#define    GPF6_out    (1<<(6*2))

void  wait(volatile unsigned long dly)
{
    for(; dly > ; dly--);
}

int main(void)
{
    unsigned long i = ;

    GPFCON = GPF4_out|GPF5_out|GPF6_out;        // 将LED1-3对应的GPF4/5/6三个引脚设为输出

    while(){
        wait();
        GPFDAT = (~(i<<));         // 根据i的值，点亮LED1-3
        if(++i == )
            i = ;
    }

    return ;
}

4、汇编调用部分：

@******************************************************************************
@ File：head.s
@ 功能：设置SDRAM，将程序复制到SDRAM，然后跳到SDRAM继续执行
@******************************************************************************       

.text
.global _start
_start:
                                            @函数disable_watch_dog, memsetup, init_nand, nand_read_ll在init.c中定义
            ldr     sp, =               @设置堆栈
            bl      disable_watch_dog       @关WATCH DOG
            bl      memsetup                @初始化SDRAM
            bl      nand_init               @初始化NAND Flash

                                            @将NAND Flash中地址4096开始的1024字节代码(main.c编译得到)复制到SDRAM中
                                            @nand_read_ll函数需要3个参数：
            ldr     r0,     =0x30000000     @. 目标地址=0x30000000，这是SDRAM的起始地址
            mov     r1,     #           @.  源地址   = ，连接的时候，main.c中的代码都存在NAND Flash地址4096开始处
            mov     r2,     #           @.  复制长度= (bytes)，对于本实验的main.c，这是足够了
            bl      nand_read               @调用C函数nand_read

            ldr     sp, =0x34000000         @设置栈
            ldr     lr, =halt_loop          @设置返回地址
            ldr     pc, =main               @b指令和bl指令只能前后跳转32M的范围，所以这里使用向pc赋值的方法进行跳转
halt_loop:
            b       halt_loop

5、链接地址指定，验证读取2049地址的数据：nand.lds

SECTIONS {
  firtst      0x00000000 : { head.o init.o nand.o}
  second     0x30000000 : AT() { main.o }
}
 

6、Makefile

objs := head.o init.o nand.o main.o

nand.bin : $(objs)
    arm-linux-ld -Tnand.lds    -o nand_elf $^
    arm-linux-objcopy -O binary -S nand_elf $@
    arm-linux-objdump -D -m arm  nand_elf > nand.dis

%.o:%.c
    arm-linux-gcc -Wall -c -O2 -o $@ $<

%.o:%.S
    arm-linux-gcc -Wall -c -O2 -o $@ $<

clean:
    rm -f  nand.dis nand.bin nand_elf *.o