2440超详细uboot移植笔记(十一)------支持NAND FLASH

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a.在s3c2440_nand.c(路径:drivers\mtd\nand\s3c2440_nand.c)文件中把board_nand_init函数里的:

cfg = S3C2440_NFCONF_EN;

cfg |= S3C2440_NFCONF_TACLS(tacls - 1);

cfg |= S3C2440_NFCONF_TWRPH0(twrph0 - 1);

cfg |= S3C2440_NFCONF_TWRPH1(twrph1 - 1);

这四句去掉，替换为:

cfg = ((tacls-1)<<12)|((twrph0-1)<<8)|((twrph1-1)<<4);

/* 使能NAND Flash控制器, 初始化ECC, 禁止片选 */

b.在

writel(cfg, &nand_reg->nfconf);

这句的下面添加一句:

writel ((1<<4)|(1<<1)|(1<<0),&nand_reg->nfcont);

c.
将

nand->select_chip = null;

这句话修改为:

nand->select_chip = s3c2440_nand_select;

d.将s3c2440_nand.c(路径:drivers\mtd\nand\s3c2440_nand.c)中的:
#define S3C2440_NFCONF_nFCE (1<<11)

改成:

#define S3C2440_NFCONF_nFCE (1<<1)

f.
在board_nand_init函数前面添加s3c2440_nand_select函数:

static void s3c2440_nand_select(struct mtd_info *mtd, int chipnr)

{
struct s3c24x0_nand *nand = s3c24x0_get_base_nand();

switch(chipnr)
{
case -1:/*取消选中*/
nand->nfcont |= (1<<1);
break;
case 0:
nand->nfcont &= ~(1<<1);
break;
default:
BUG();
}

}

g.将s3c2440_nand.c(路径:drivers\mtd\nand\s3c2440_nand.c)中的s3c24x0_hwcontrol函数修改为:

static void s3c24x0_hwcontrol(struct mtd_info *mtd, int dat, unsigned int ctrl)

{
struct s3c24x0_nand *nand = s3c24x0_get_base_nand();
if(ctrl & NAND_CLE)
{
/*发命令*/
writeb(dat, &nand->nfcmd);
}
else if(ctrl & NAND_ALE)
{
/*发地址*/
writeb(dat, &nand->nfaddr);
}

}

h.至此，uboot以支持NAND FLASH: