硬件平台：tq2440
开发环境：Ubuntu-3.11
u-boot版本：2014.10
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虽说nand flash读写操作是可以了，但是我使用nand markbad命令将一个块标记为坏块时，再用nand scrub命令恢复出厂设置时，却出现了下面的错误：
nand0: MTD Erase failure: -5说明我们的nand flash移植是不完全正确的。下面查找原因
在文件drivers/mtd/nand/s3c2440_nand.c中开头部分只留下这些宏，前面说过了该文件中所有的2410字样的都改成了2440了，所以不要在下面修改时有什么觉得奇怪：
#define S3C2440_NFCONF_TACLS(x) ((x)<<12)#define S3C2440_NFCONF_TWRPH0(x) ((x)<<8)#define S3C2440_NFCONF_TWRPH1(x) ((x)<<4)#define S3C2440_NFCONT_EN (1<<0)#define S3C2440_NFCONT_INITECC (1<<4)#define S3C2440_NFCONT_nFCE (1<<1)#define S3C2440_NFCONT_MAINECCLOCK (1<<5)#define S3C2440_ADDR_NALE 8#define S3C2440_ADDR_NCLE 0x0c之前很多宏定义的是2410的nand flash寄存器的位，在2440上就有很多不同了，比如原来在NFCONF寄存器中的内容移到了NFCONT寄存器中去了。
修改s3c2440_hwcontrol函数中不再是S3C2440_NFCONF_nFCE宏，而是S3C2440_NFCONT_nFCE宏：
static void s3c2440_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl){struct nand_chip *chip = mtd->priv;struct s3c2440_nand *nand = s3c2440_get_base_nand();debug("hwcontrol(): 0x%02x 0x%02x\n", cmd, ctrl);if (ctrl & NAND_CTRL_CHANGE) {ulong IO_ADDR_W = (ulong)nand;if (!(ctrl & NAND_CLE))IO_ADDR_W |= S3C2440_ADDR_NCLE;if (!(ctrl & NAND_ALE))IO_ADDR_W |= S3C2440_ADDR_NALE;if(cmd == NAND_CMD_NONE)IO_ADDR_W = (ulong)&nand->nfdata;chip->IO_ADDR_W = (void *)IO_ADDR_W;if (ctrl & NAND_NCE) /* 使能选中 */writel(readl(&nand->nfconf) & ~S3C2440_NFCONT_nFCE,&nand->nfconf);else /* 取消选中 */writel(readl(&nand->nfconf) | S3C2440_NFCONT_nFCE,&nand->nfconf);}if (cmd != NAND_CMD_NONE)writeb(cmd, chip->IO_ADDR_W);}
在s3c2440_nand_enable_hwecc函数中修改：
void s3c2440_nand_enable_hwecc(struct mtd_info *mtd, int mode){struct s3c2440_nand *nand = s3c2440_get_base_nand();debug("s3c2440_nand_enable_hwecc(%p, %d)\n", mtd, mode);writel(((readl(&nand->nfconf) | S3C2440_NFCONT_INITECC) & (~S3C2440_NFCONT_MAINECCLOCK)), &nand->nfconf);}
在arch/arm/include/asm/arch-s3c24x0/s3c24x0.h文件中修改：
/* NAND FLASH (see S3C2440 manual chapter 6) */struct s3c2440_nand {u32 nfconf;u32 nfcont;u32 nfcmd;u32 nfaddr;u32 nfdata;u32 nfeccd0;u32 nfeccd1;u32 nfeccd;u32 nfstat;u32 nfstat0;u32 nfstat1;u32 nfmecc0;u32 nfmecc1;u32 nfsecc;u32 nfsblk;u32 nfeblk;};注：arch/arm/include/asm/目录下的arch目录其实是arch/arm/include/asm/arch-s3c24x0/目录的符号链接。在s3c2440_nand_calculate_ecc函数中修改：static int s3c2440_nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat,u_char *ecc_code){struct s3c2440_nand *nand = s3c2440_get_base_nand();ecc_code[0] = readb(&nand->nfmecc0);ecc_code[1] = readb(&nand->nfmecc0 + 1);ecc_code[2] = readb(&nand->nfmecc0 + 2);ecc_code[3] = readb(&nand->nfmecc0 + 3); debug("s3c2440_nand_calculate_hwecc(%p,): 0x%02x 0x%02x 0x%02x 0x%02x\n", mtd , ecc_code[0], ecc_code[1], ecc_code[2], ecc_code[3]);return 0;} 在s3c2440_nand_correct_data函数中修改：static int s3c2440_nand_correct_data(struct mtd_info *mtd, u_char *dat,u_char *read_ecc, u_char *calc_ecc){struct s3c2440_nand *nand = s3c2440_get_base_nand();u32 estat0,err_byte_addr;int ret = -1;u8 repaired;writel((read_ecc[1] << 16) | read_ecc[0],&nand->nfeccd0);writel((read_ecc[3] << 16) | read_ecc[2],&nand->nfeccd1);/* Read ecc status */estat0= readl(&nand->nfstat);switch(estat0 & 0x3) {case 0: /* No error */ret= 0;break;case 1:/** 1 bit error (Correctable)* (nfestat0 >> 7) & 0x7ff :error byte number* (nfestat0 >> 4) & 0x7:error bit number**/err_byte_addr= (estat0 >> 7) & 0x7ff;repaired= dat[err_byte_addr] ^ (1 << ((estat0 >> 4) & 0x7));printf("S3C NAND: 1 bit error detected at byte%d. ""Correcting from 0x%02x to0x%02x…OK\n",err_byte_addr, dat[err_byte_addr],repaired);dat[err_byte_addr]= repaired;ret= 1;break;case 2: /* Multiple error */case 3: /* ECC area error */printf("S3C NAND: ECC uncorrectable errordetected. ""Not correctable.\n");ret= -1;break;}return ret;}
删除s3c2440_nand_select函数：static void s3c2440_nand_select(struct mtd_info *mtd, int chipnr){struct s3c2440_nand *nand = s3c2440_get_base_nand();switch(chipnr){case -1: /* 取消选中 */nand->nfcont |= (1<<1);break;case 0: /* 选中 */nand->nfcont &= ~(1 << 1);break;default:BUG();}return;}让所有的愁向后飞去。请不要回头去追你因该向前奔跑，因为快乐在前方!
