UBOOT-2010.06 移植 支持 下载yaffs2文件系统 （九）

参考：http://blog.csdn.net/IT_114

在自己2.6.33 内核中，分区是：

1. static struct mtd_partition smdk_default_nand_part[] = {
   2. #if defined (CONFIG_256MB_NAND)
   3.     [0] = {
   4.         .name    = "ywx-uboot",
   5.         .size    = 0x00040000,   ##256KB
   6.         .offset    = 0x0,
   7.     },
   8.     [1] = {
   9.         .name    = "ywx-kernel",
  10.         .offset = 0x00200000,
  11.         .size    = 0x00200000,   ##2MB
  12.     },
  13.     [2] = {
  14.         .name    = "ywx-yaffs2",
  15.         .offset = 0x00400000,
  16.         .size    = 0x0fb80000,  ##251.5MB
  17.     }
  18. #endif
  19. };

在 uboot 中分区如下：

0~0x40000 u-boot （256K）

0x200000~0x400000 kernel  (2M)

0x400000~~ (剩余的)

1、通 常一个Nnad Flash存储设备由若干块组成，1个块由若干页组成。一般128MB以下容量的Nand Flash芯片，一页大小为528B，被依次分为2个256B的主数据区和16B的额外空间。128MB以上容量的Nand Flash芯片，一页大小通常为2KB。由于Nand Flash出现位反转的概率较大，一般在读写时需要使用ECC进行错误检验和恢复。TQ2440上的Nandflash型号是K9F2G08，页面大小为 page = 2K + 64Byte。

    Yaffs/yaffs2 文件系统的设计充分考虑到Nand Flash以页为存取单位等的特点，将文件组织成固定大小的段(Chunk)。以528B的页为例，Yaffs/yaffs2文件系统使用前512B存储 数据和16B的额外空间存放数据的ECC和文件系统的组织信息等(称为OOB数据)。通过OOB数据，不但能实现错误检测和坏块处理，同时还可以避免加载 时对整个存储介质的扫描，加快了文件系统的加载速度。以下是Yaffs/yaffs2文件系统页的结构说明

           Yaffs页结构说明
==============================================
   字节                   用途
==============================================
 0 - 511                存储数据(分为两个半部)
512 - 515               系统信息
   516                  数据状态字
   517                  块状态字
518 - 519               系统信息
520 - 522               后半部256字节的ECC
523 - 524               系统信息
525 - 527               前半部256字节的ECC
==============================================

好了，在了 解Nand Flash组成和Yaffs/yaffs2文件系统结构后，我们再回到u-boot中。目前，在u-boot中已经有对Cramfs、Jffs2等文件系 统的读写支持，但与带有数据校验等功能的OOB区的Yaffs/Yaffs2文件系统相比，他们是将所有文件数据简单的以线性表形式组织的。所以，我们只 要在此基础上通过修改u-boot的Nand Flash读写命令，增加处理00B区域数据的功能，即可以实现对Yaffs/Yaffs2文件系统的读写支持。

 

2、在include/configs/smdk2440.h头文件中定义一个管理对Yaffs2支持的宏和开启u-boot中对Nand Flash默认分区的宏，如下：

vi include/configs/smdk2440.h

//定义一个管理对Yaffs2支持的宏
#define CONFIG_MTD_NAND_YAFFS2   1
//开启Nand Flash默认分区，注意此处的分区要和你的内核中的分区保持一致
#define MTDIDS_DEFAULT "nand0=nandflash0"
#define MTDPARTS_DEFAULT "mtdparts=nandflash0:256k(bootloader)," \
                                                            "2m(kernel)," \
                                                            "-(root)"

3、在原来对Nand操作的命令集列表中添加Yaffs2对Nand的写命令，如下：

vi common/cmd_nand.c

在函数U_BOOT_CMD中添加如下：

//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

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"

/*添加 开始*/

/*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

/*添加结束*/

    "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
);

接着，在该文件中对nand操作的do_nand函数中添加yaffs2对nand的操作，如下：

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);
        }

/*添加开始*/

/*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
/*添加结束*/

        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;
    }

在include/linux/mtd/mtd.h头文件的mtd_info结构体中添加上面用到rw_oob和skipfirstblk数据成员，如下：

#vi 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

在第二步关联的nand_write_skip_bad函数中添加对Nand OOB的相关操作，如下：

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

上传 nand_util.c 附件    nand_util.rar  

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;

/*添加 开始*/

#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

/*添加 结束*/

    /* 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;
    }


/*修改 开始*/
#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
/*修改 结束*/


    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;
        }


/*添加 开始*/
#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

/*添加 结束*/


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

/*添加 开始*/

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

        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;
        offset        += write_size;

/*添加 开始*/
#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
/*添加 结束*/

    }

    return 0;
}

OK，对yaffs2支持的代码已修改完毕，重新编译u-boot并下载到nand中，启动开发板，在u-boot的命令行输入:nand help查看nand的命令，可以看到多了一个nand write[.yaffs2]的命令，这个就是用来下载yaffs2文件系统到nand中的命令了。

make smdk2440_config && make all

然后设置，DNW的地址为 0x0， 把根目录下的u-boot.bin 下载到Nandflash的地址0处

1.选择 nor flash启动模式

2.进入 nor flash 下载模式界面

3.选择 “1”

   [1] Download u-boot or STEPLDR.nb1 or other bootloader to Nand Flash

4.下载成功后，关机。

5.拨到从 nand flash 启动模式

6.打开电源，开机

U-Boot 2010.06-rc1 ( 4鏈?17 2011 - 10:15:21)

DRAM:  64 MiB
Flash: 2 MiB
NAND:  256 MiB
In:    serial
Out:   serial
Err:   serial
Net:   dm9000
[SMDK2440]# nand help
nand - NAND sub-system

Usage:
nand info - show available NAND devices
nand device [dev] - show or set current device
nand read - addr off|partition size
nand write - addr off|partition size
    read/write 'size' bytes starting at offset 'off'
    to/from memory address 'addr', skipping bad blocks.
nand write[.yaffs2] - addr off|partition size - write `size' byte yaffs image
 starting at offset off' from memory address addr' (.yaffs2 for 512+16 NAND)
nand erase [clean] [off size] - erase 'size' bytes from
    offset 'off' (entire device if not specified)
nand bad - show bad blocks
nand dump[.oob] off - dump page
nand scrub - really clean NAND erasing bad blocks (UNSAFE)
nand markbad off [...] - mark bad block(s) at offset (UNSAFE)
nand biterr off - make a bit error at offset (UNSAFE)
[SMDK2440]#