启动文件head.s源码:

@******************************************************************************

@ 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, =4096                @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 @1. 目标地址=0x30000000，这是SDRAM的起始地址

   mov   r1,     #4096       @2. 源地址=4096，链接的时，main.c中的代码都存在NAND Flash地址4096开始处

   mov   r2,     #2048       @3.  复制长度= 2048(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

=====================================================================

init.c源码：

// 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    = 0;

}

// 设置控制SDRAM的13个寄存器 

void memsetup()

{

    int     i = 0;

    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 < 13; i++)

        p[i] = mem_cfg_val[i];

}

=====================================================================

nand.c源码：

#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 

    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)

{

    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；nand flash在烧写的时候可以自动跳过坏块，在读取的时候也应该能自动识别坏块并跳过，

// 可以参考“ALSA声卡裸板之编译和测试”章节的nand_read函数，实现了读取nand flash数据时检查坏块

// 并跳过读取的功能。

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 ;

}

=====================================================================

main.c源码：

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

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

#define    GPF4_out    (1<

#define    GPF5_out    (1<

#define    GPF6_out    (1<

void  wait(volatile unsigned long dly)

{

    for(; dly > 0; dly--);

}

int main(void)

{

    unsigned long i = 0;

    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(1){

        wait(30000);

        GPFDAT = (~(i<<4));         // 根据i的值，点亮LED1-3

        if(++i == 8)

            i = 0;

    }

    return 0;

}

=====================================================================

Makefile文件：

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 $@ $<