住上篇！！！！！！！！！！！
5.添加支持nandflash读写驱动：（此部分程序是在内核里的nandflash驱动移植过来的）
（1）增加nand_flash.c文件：cpu/arm920t/s3c24x0/nand_flash.c内容如下：
#include <common.h>
#if (CONFIG_COMMANDS & CFG_CMD_NAND) && !defined(CFG_NAND_LEGACY)
#include <s3c2410.h>
#include <nand.h>
DECLARE_GLOBAL_DATA_PTR;
#define S3C2440_NFSTAT_READY (1<<0)
#define S3C2440_NFCONT_nFCE (1<<1)
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 NCE\n", __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)
{
S3C2440_NAND * const s3c2440nand = S3C2440_GetBase_NAND();
#define TACLS 0
#define TWRPH0 4
#define TWRPH1 2
s3c2440nand->NFCONF = (TACLS<<12)|(TWRPH0<<8)|(TWRPH1<<4);
s3c2440nand->NFCONT = (1<<4)|(0<<1)|(1<<0);
}
void board_nand_init(struct nand_chip *chip)
{
S3C2440_NAND * const s3c2440nand = S3C2440_GetBase_NAND();
s3c24x0_nand_inithw();
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
（2）跟住修改该目录下既Makefile：大概29行
COBJS = i2c.o interrupts.o serial.o speed.o \
usb_ohci.o nand_flash.o
（3）系include/s3c24x0.h中定义S3C2440_NAND结构体，大概在168行
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）跟住在include/s3c2410.h的大概100行位置加：
static inline S3C2440_NAND * const S3C2440_GetBase_NAND(void)
{
return (S3C2440_NAND * const)S3C2410_NAND_BASE;
}
（5）跟住就修改配置文件include/configs/yangyi2440.h修改Flash的配置
和NAND的设置：178行
//#define CFG_ENV_IS_IN_FLASH 1(屏蔽左距)
#define CFG_ENV_IS_IN_NAND 1
#define CFG_ENV_OFFSET 0x40000//偏移地址，呢个系因为它接在bank的地址
#define CFG_ENV_SIZE 0xc000 //64M
#define CFG_NAND_BASE 0
#define CFG_MAX_NAND_DEVICE 1//板上有多少个nandflash设备
#define NAND_MAX_CHIPS 1 //一个NANDFLASH设备有多少片
（6）修改配置文件include/configs/yangyi2440.h,增加nandflash命令：
把#define CONFIG_COMMANDS 离得CFG_CMD_NAND屏蔽去掉。
执行make clean 再 make all 。编译Ok通过。艮就支持呢NANDFLASH读写擦操作功能啦
