支持NAND Flash

    1. 首先在配置文件 include/config/fl2440.h 的宏 CONFIG_COMMANDS 中增加 CFG_CMD_NAND，

#define CONFIG_COMMANDS
   (CONFIG_CMD_DFL  |
   CFG_CMD_CACHE  |
   CFG_CMD_NAND  |
   

2.在配置文件 include/configs/fl2440.h 中增加如下3个宏

#define CFG_NAND_BASE 0 //无实际意义：基地址，在board_nand_init中重新定义

#define CFG_MAX_NAND_DEVICE 1 //NAND Flash设备数目为1

#define NAND_MAX_CHIPS 1 //每个NAND设备由1个NADN芯片组成

3.在 include/s3c24x0.h 文件中增加s3c2440_NAND 数据结构

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;

4.在 includ/s3c2410.h 文件中仿照 s3c2410_GetBase_NAND 函数定义 S3C2440_GetBase_NAND 函数

static inline S3C2440_NAND * const S3C2440_GetBase_NAND(void)
   {
       return (S3C2440_NAND * const)S3C2410_NAND_BASE;

5.在 cpu/arm920t/s3c24x0 下新建nand_flash.c文件，代码如下。

#include

#include

#if (CONFIG_COMMANDS & CFG_CMD_NAND) && !defined(CFG_NAND_LEGACY)
#include
#include

DECLARE_GLOBAL_DATA_PTR;

#define S3C2410_NFSTAT_READY    (1<<0)
#define S3C2410_NFCONF_nFCE     (1<<11)

#define S3C2440_NFSTAT_READY    (1<<0)
#define S3C2440_NFCONT_nFCE     (1<<1)

static void s3c2410_nand_select_chip(struct mtd_info *mtd, int chip)
{
S3C2410_NAND * const s3c2410nand = S3C2410_GetBase_NAND();

    if (chip == -1) {
        s3c2410nand->NFCONF |= S3C2410_NFCONF_nFCE;   
    } else {
        s3c2410nand->NFCONF &= ~S3C2410_NFCONF_nFCE;    
    }
}

static void s3c2410_nand_hwcontrol(struct mtd_info *mtd, int cmd)
{
    S3C2410_NAND * const s3c2410nand = S3C2410_GetBase_NAND();
    struct nand_chip *chip = mtd->priv;

    switch (cmd) {
    case NAND_CTL_SETNCE:
    case NAND_CTL_CLRNCE:
        printf("%s: called for NCEn", __FUNCTION__);
        break;

    case NAND_CTL_SETCLE:
        chip->IO_ADDR_W = (void *)&s3c2410nand->NFCMD;
        break;

    case NAND_CTL_SETALE:
        chip->IO_ADDR_W = (void *)&s3c2410nand->NFADDR;
        break;
}
}
static int s3c2410_nand_devready(struct mtd_info *mtd)
{
    S3C2410_NAND * const s3c2410nand = S3C2410_GetBase_NAND();

    return (s3c2410nand->NFSTAT & S3C2410_NFSTAT_READY);
}

static void s3c2440_nand_select_chip(struct mtd_info *mtd, int chip)
{
    S3C2440_NAND * const s3c2440nand = S3C2440_GetBase_NAND();

    if (chip == -1) {
        s3c2440nand->NFCONT |= S3C2440_NFCONT_nFCE;
    } else {
        s3c2440nand->NFCONT &= ~S3C2440_NFCONT_nFCE;
    }
}

static void s3c2440_nand_hwcontrol(struct mtd_info *mtd, int cmd)
{
    S3C2440_NAND * const s3c2440nand = S3C2440_GetBase_NAND();
    struct nand_chip *chip = mtd->priv;

    switch (cmd) {
    case NAND_CTL_SETNCE:
    case NAND_CTL_CLRNCE:
        printf("%s: called for NCEn", __FUNCTION__);
        break;

    case NAND_CTL_SETCLE:
        chip->IO_ADDR_W = (void *)&s3c2440nand->NFCMD;
        break;

    case NAND_CTL_SETALE:
        chip->IO_ADDR_W = (void *)&s3c2440nand->NFADDR;
        break;

    default:
        chip->IO_ADDR_W = (void *)&s3c2440nand->NFDATA;
        break;
    }
}

static int s3c2440_nand_devready(struct mtd_info *mtd)
{
    S3C2440_NAND * const s3c2440nand = S3C2440_GetBase_NAND();

    return (s3c2440nand->NFSTAT & S3C2440_NFSTAT_READY);
}

static void s3c24x0_nand_inithw(void)
{
    S3C2410_NAND * const s3c2410nand = S3C2410_GetBase_NAND();
    S3C2440_NAND * const s3c2440nand = S3C2440_GetBase_NAND();

#define TACLS   0
#define TWRPH0  4
#define TWRPH1  2

    if (gd->bd->bi_arch_number == MACH_TYPE_SMDK2410)
    {
        s3c2410nand->NFCONF = (1<<15)|(1<<12)|(1<<11)|(TACLS<<8)|(TWRPH0<<4)|(TWRPH1<<0);
    }
    else
    {
        s3c2440nand->NFCONF = (TACLS<<12)|(TWRPH0<<8)|(TWRPH1<<4);
        s3c2440nand->NFCONT = (1<<4)|(0<<1)|(1<<0);
    }
}

void board_nand_init(struct nand_chip *chip)
{
    S3C2410_NAND * const s3c2410nand = S3C2410_GetBase_NAND();
    S3C2440_NAND * const s3c2440nand = S3C2440_GetBase_NAND();

    s3c24x0_nand_inithw();

    if (gd->bd->bi_arch_number == MACH_TYPE_SMDK2410) {
        chip->IO_ADDR_R    = (void *)&s3c2410nand->NFDATA;
        chip->IO_ADDR_W    = (void *)&s3c2410nand->NFDATA;
        chip->hwcontrol    = s3c2410_nand_hwcontrol;
        chip->dev_ready    = s3c2410_nand_devready;
        chip->select_chip  = s3c2410_nand_select_chip;
        chip->options      = 0;   
    } else {
        chip->IO_ADDR_R    = (void *)&s3c2440nand->NFDATA;
        chip->IO_ADDR_W    = (void *)&s3c2440nand->NFDATA;
        chip->hwcontrol    = s3c2440_nand_hwcontrol;
        chip->dev_ready    = s3c2440_nand_devready;
        chip->select_chip  = s3c2440_nand_select_chip;
        chip->options      = 0;    
    }

    chip->eccmode       = NAND_ECC_SOFT;    
}

#endif

    6.修改cpu/arm920t/s3c24x0/Makefile：

COBJS = 加上一项nand_flash.o

7.修改 cpu/arm920t/s3c24x0/Makefile文件如下

COBJS = i2c.o interrupts.o serial.o speed.o
   usb_ohci.o nand_flash.o

现在就可以编译了，如果出现错误

文件格式错误: failed to merge target specific data of file /usr/local/arm/3.3.2/lib/gcc-lib/arm-linux/3.3.2/libgcc.a(_clz.oS)

修改 cpu/arm920t/config.mk 文件如下（不使用软浮点进行编译，即用硬浮点进行编译）

PLATFORM_RELFLAGS += -fno-strict-aliasing  -fno-common -ffixed-r8
#   -msoft-float

可以使用新编译的U-Boot.bin烧入NAND Flash了。