u-boot-2009.08在2440上的移植详解（五）

#gedit common/cmd_nand.c   //在U_BOOT_CMD中添加

U_BOOT_CMD(nand, CONFIG_SYS_MAXARGS, 1, do_nand,
    "NAND sub-system",
    "info - show available NAND devices/n"
    "nand device [dev] - show or set current device/n"
    "nand read - addr off|partition size/n"
    "nand write - addr off|partition size/n"
    " read/write 'size' bytes starting at offset 'off'/n"
    " to/from memory address 'addr', skipping bad blocks./n"

//注意：这里只添加了yaffs2的写命令，因为我们只用u-boot下载(即写)功能，所以我们没有添加yaffs2读的命令
#if defined(CONFIG_MTD_NAND_YAFFS2)
    "nand write[.yaffs2] - addr off|partition size - write `size' byte yaffs image/n"
    " starting at offset off' from memory address addr' (.yaffs2 for 512+16 NAND)/n"
#endif

    "nand erase [clean] [off size] - erase 'size' bytes from/n"
    " offset 'off' (entire device if not specified)/n"
    "nand bad - show bad blocks/n"
    "nand dump[.oob] off - dump page/n"
    "nand scrub - really clean NAND erasing bad blocks (UNSAFE)/n"
    "nand markbad off [...] - mark bad block(s) at offset (UNSAFE)/n"
    "nand biterr off - make a bit error at offset (UNSAFE)"
#ifdef CONFIG_CMD_NAND_LOCK_UNLOCK
    "/n"
    "nand lock [tight] [status]/n"
    " bring nand to lock state or display locked pages/n"
    "nand unlock [offset] [size] - unlock section"
#endif
);

    if (strncmp(cmd, "read", 4) == 0 || strncmp(cmd, "write", 5) == 0) 
    {
        int read;

        if (argc <4)
            goto usage;

        addr = (ulong)simple_strtoul(argv[2], NULL, 16);

        read = strncmp(cmd, "read", 4) == 0; /* 1 = read, 0 = write */
        printf("/nNAND %s: ", read ? "read" : "write");
        if (arg_off_size(argc - 3, argv + 3, nand, &off, &size) != 0)
            return 1;

        s = strchr(cmd, '.');
        if (!s || !strcmp(s, ".jffs2") || !strcmp(s, ".e") || !strcmp(s, ".i")) 
        {
            if (read)
                ret = nand_read_skip_bad(nand, off, &size, (u_char *)addr);
            else
                ret = nand_write_skip_bad(nand, off, &size, (u_char *)addr);
        }

//添加yaffs2相关操作，注意该处又关联到nand_write_skip_bad函数

#if defined(CONFIG_MTD_NAND_YAFFS2)
        else if (s != NULL && (!strcmp(s, ".yaffs2")))
        {
            nand->rw_oob = 1;
            nand->skipfirstblk = 1;
            ret = nand_write_skip_bad(nand,off,&size,(u_char *)addr);
            nand->skipfirstblk = 0;
            nand->rw_oob = 0;
        }
#endif

        else if (!strcmp(s, ".oob")) 
        {
            /* out-of-band data */
            mtd_oob_ops_t ops = 
            {
                .oobbuf = (u8 *)addr,
                .ooblen = size,
                .mode = MTD_OOB_RAW
            };

            if (read)
                ret = nand->read_oob(nand, off, &ops);
            else
                ret = nand->write_oob(nand, off, &ops);
        } 
        else 
        {
            printf("Unknown nand command suffix '%s'./n", s);
            return 1;
        }

        printf(" %zu bytes %s: %s/n", size, read ? "read" : "written", ret ? "ERROR" : "OK");

        return ret == 0 ? 0 : 1;
    }

#gedit include/linux/mtd/mtd.h   //在mtd_info结构体中添加

#if defined(CONFIG_MTD_NAND_YAFFS2)
    u_char rw_oob;
    u_char skipfirstblk;
#endif

#gedit drivers/mtd/nand/nand_util.c  //在nand_write_skip_bad函数中添加

int nand_write_skip_bad(nand_info_t *nand, loff_t offset, size_t *length, u_char *buffer)
{
    int rval;
    size_t left_to_write = *length;
    size_t len_incl_bad;
    u_char *p_buffer = buffer;

#if defined(CONFIG_MTD_NAND_YAFFS2) //add yaffs2 file system support
    if(nand->rw_oob==1)    
    {
        size_t oobsize = nand->oobsize;
        size_t datasize = nand->writesize;
        int datapages = 0;

        if (((*length)%(nand->oobsize+nand->writesize)) != 0) 
        {
         printf ("Attempt to write error length data!/n");
         return -EINVAL;
     }

        datapages = *length/(datasize+oobsize);
        *length = datapages*datasize;
        left_to_write = *length;
    }
#endif

    /* Reject writes, which are not page aligned */
    if ((offset & (nand->writesize - 1)) != 0 ||
     (*length & (nand->writesize - 1)) != 0) {
        printf ("Attempt to write non page aligned data/n");
        return -EINVAL;
    }

    len_incl_bad = get_len_incl_bad (nand, offset, *length);

    if ((offset + len_incl_bad) >= nand->size) {
        printf ("Attempt to write outside the flash area/n");
        return -EINVAL;
    }

#if !defined(CONFIG_MTD_NAND_YAFFS2) //add yaffs2 file system support
    if (len_incl_bad == *length) {
        rval = nand_write (nand, offset, length, buffer);
        if (rval != 0)
            printf ("NAND write to offset %llx failed %d/n",
                offset, rval);

        return rval;
    }
#endif

    while (left_to_write > 0) {
        size_t block_offset = offset & (nand->erasesize - 1);
        size_t write_size;

        WATCHDOG_RESET ();

        if (nand_block_isbad (nand, offset & ~(nand->erasesize - 1))) {
            printf ("Skip bad block 0x%08llx/n",
                offset & ~(nand->erasesize - 1));
            offset += nand->erasesize - block_offset;
            continue;
        }

#if defined(CONFIG_MTD_NAND_YAFFS2) //add yaffs2 file system support
        if(nand->skipfirstblk==1)    
        {
            nand->skipfirstblk=0;
            printf ("Skip the first good block %llx/n", offset & ~(nand->erasesize - 1));
            offset += nand->erasesize - block_offset;
            continue;
        }
#endif

        if (left_to_write <(nand->erasesize - block_offset))
            write_size = left_to_write;
        else
            write_size = nand->erasesize - block_offset;

        printf("/rWriting at 0x%llx -- ",offset); //add yaffs2 file system support

        rval = nand_write (nand, offset, &write_size, p_buffer);
        if (rval != 0) {
            printf ("NAND write to offset %llx failed %d/n",
                offset, rval);
            *length -= left_to_write;
            return rval;
        }

        left_to_write -= write_size;
        printf("%d%% is complete.",100-(left_to_write/(*length/100)));
        offset += write_size;

#if defined(CONFIG_MTD_NAND_YAFFS2) //add yaffs2 file system support
        if(nand->rw_oob==1)    
        {
            p_buffer += write_size+(write_size/nand->writesize*nand->oobsize);
        } 
        else    
        {
            p_buffer += write_size;
        }
#else
        p_buffer += write_size;
#endif

    }

    return 0;
}

#gedit drivers/mtd/nand/nand_base.c  //在nand_write函数中添加

static int nand_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const uint8_t *buf)
{
    struct nand_chip *chip = mtd->priv;
    int ret;

#if defined(CONFIG_MTD_NAND_YAFFS2) //add yaffs2 file system support

    int oldopsmode = 0;

    if(mtd->rw_oob==1)    
    {
        int i = 0;
        int datapages = 0;

        size_t oobsize = mtd->oobsize;
        size_t datasize = mtd->writesize;

        uint8_t oobtemp[oobsize];
        datapages = len / (datasize);

        for(i = 0; i <(datapages); i++)    
        {
            memcpy((void *)oobtemp, (void *)(buf + datasize * (i + 1)), oobsize);
            memmove((void *)(buf + datasize * (i + 1)), (void *)(buf + datasize * (i + 1) + oobsize), (datapages - (i + 1)) * (datasize) + (datapages - 1) * oobsize);
            memcpy((void *)(buf+(datapages) * (datasize + oobsize) - oobsize), (void *)(oobtemp), oobsize);
        }
    }
#endif

    /* Do not allow reads past end of device */
    if ((to + len) > mtd->size)
        return -EINVAL;
    if (!len)
        return 0;

    nand_get_device(chip, mtd, FL_WRITING);

    chip->ops.len = len;
    chip->ops.datbuf = (uint8_t *)buf;

#if defined(CONFIG_MTD_NAND_YAFFS2) //add yaffs2 file system support

    if(mtd->rw_oob!=1)    
    {
        chip->ops.oobbuf = NULL;
    } 
    else    
    {
        chip->ops.oobbuf = (uint8_t *)(buf + len);
        chip->ops.ooblen = mtd->oobsize;
        oldopsmode = chip->ops.mode;
        chip->ops.mode = MTD_OOB_RAW;
    }
#else
    chip->ops.oobbuf = NULL;
#endif

    ret = nand_do_write_ops(mtd, to, &chip->ops);

    *retlen = chip->ops.retlen;

    nand_release_device(mtd);

#if defined(CONFIG_MTD_NAND_YAFFS2) //add yaffs2 file system support

    chip->ops.mode = oldopsmode;
#endif

    return ret;
}

tftp 0x30000000 root-2.6.30.4.bin //用tftp将yaffs2文件系统下载到内存的0x30000000位置

nand erase 0x250000 0x3dac000 //擦除Nand的文件系统分区

nand write.yaffs2 0x30000000 0x250000 0x658170 //将内存中的yaffs2文件系统写入Nand的文件系统分区，注意这里的0x658170是yaffs2文件系统的实际大小(可以在tftp传送完后可以看到)，要写正确，否则会形成假坏块