jff2根文件系统制作

今天药忘吃喽~ 2022-05-28 11:40 431阅读 0赞

上一次中，我们发现烧录Linux内核时，单纯的的内核文件烧到单片机中，系统会无法跑起来，根本原因就没有挂载点，找不到文件系统，这一次我们来制作基于jffs2根文件系统的制作。

# 1. jff2文件系统简介 #

jff2是专门针对Norflash而设计的文件系统，这种文件系统是直接存放在flash上面，掉电后不丢失，区别于initramfs，小页的Nandflash也可以使用，只是效率不高。这里是Norflash和  
Nandflash的简单区别1。

# 2. 库准备 #

## 2.1 VFS ##

我们都知道，Linux能兼容比较多的是因为嵌入式这方面都会屏蔽底层硬件，要求良好的兼容性，移植性强。用户完全不需要知道这些底层文件系统的具体实现，这主要归功于VFS(Virtual File System)。VFS具有以下特性：

1.  向上提供标准文件操作接口 ；
2.  向下对所以文件系统提供统一标准接口 ；
3.  VFS把一些复杂的操作尽量抽象到VFS内部，使得底层文件系统实现更简单。

## 2.2 工具源码准备-mtd-utils移植 ##

### 创建工作路径 ###

[klaus@localhost jffs+ker_fl2440]$ ls
    3rdparty  bootloader  crosstool  driver  images  linux  program
    [klaus@localhost jffs+ker_fl2440]$ mkdir -p x86_tools/mtd_utils

### 库准备 ###

1.编译lzo库，生成静态库

[klaus@localhost jffs+ker_fl2440]$ cd x86_tools/mtd_utils/
    [klaus@localhost mtd_utils]$ wget http://www.oberhumer.com/opensource/lzo/download/lzo-2.10.tar.gz
    
    [klaus@localhost mtd_utils]$ tar -xzf lzo-2.10.tar.gz
    [klaus@localhost mtd_utils]$ cd lzo-2.10
    [klaus@localhost lzo-2.10]$  ./configure --prefix=`pwd`/../install --enable-static --disable-shared
    configure: Configuring LZO 2.10
    checking build system type... x86_64-pc-linux-gnu
    ... ... ...
    Type 'make' to build LZO.
    Type 'make check' and 'make test' to test LZO.
    Type 'make install' to install LZO.
    After installing LZO, please have a look at 'examples/simple.c'.
    
    [klaus@localhost lzo-2.10]$

2.编译zlib库

[klaus@localhost lzo-2.10]$ cd ..
    [klaus@localhost mtd_utils]$ wget https://github.com/madler/zlib/archive/v1.2.10.tar.gz -O zlib-1.2.10.tar.gz
    [klaus@localhost mtd_utils]$ tar -xzf zlib-1.2.10.tar.gz
    [klaus@localhost mtd_utils]$ cd zlib-1.2.10
    [klaus@localhost zlib-1.2.10]$ ./configure --prefix=`pwd`/../install --static
    [klaus@localhost zlib-1.2.10]$ make && make install

3.编译e2fsprogs库(libuuid)

[klaus@localhost zlib-1.2.10]$ cd ..
    [klaus@localhost mtd_utils]$ wget https://github.com/tytso/e2fsprogs/archive/v1.43.7.tar.gz -O e2fsprogs-1.43.7.tar.gz
    [klaus@localhost mtd_utils]$ tar -xzf e2fsprogs-1.43.7.tar.gz
    [klaus@localhost mtd_utils]$ cd e2fsprogs-1.43.7
    [klaus@localhost e2fsprogs-1.43.7]$ ./configure --prefix=`pwd`/../install --enable-elf-shlibs --enable-libuuid
    [klaus@localhost e2fsprogs-1.43.7]$  make ; make install-libs

4.编译mtd-utils并安装mkfs.jffs2和mkfs.ubifs

[klaus@localhost e2fsprogs-1.43.7]$ cd ..
    [klaus@localhost mtd_utils]$ wget ftp://ftp.infradead.org/pub/mtd-utils/mtd-utils-1.5.2.tar.bz2
    [klaus@localhost mtd_utils]$ tar -xjf mtd-utils-1.5.2.tar.bz2
    [klaus@localhost mtd_utils]$ cd mtd-utils-1.5.2
    [klaus@localhost mtd-utils-1.5.2]$ export CFLAGS+=" -I../install/include/ "
    [klaus@localhost mtd-utils-1.5.2]$ export LDFLAGS+=" -L../install/lib/ -static "
    [klaus@localhost mtd-utils-1.5.2]$ make WITHOUT_XATTR=1

5.根文件系统工具制作

[klaus@localhost mtd-utils-1.5.2]$ sudo cp mkfs.jffs2 /bin/
    [sudo] password for klaus: 
    [klaus@localhost mtd-utils-1.5.2]$ sudo cp mkfs.ubifs/mkfs.ubifs /bin/
    [klaus@localhost mtd-utils-1.5.2]$ sudo cp ubi-utils/ubinize /bin/
    [klaus@localhost mtd-utils-1.5.2]$

# 3.jff2制作 #

## 3.1 镜像制作 ##

可直接在上一次做好的文件系统树上进行修改

[klaus@localhost rootfs_fl2440]$ sudo cp -r rootfs/* ../jffs+ker_fl2440/linux/rootfs/
    [sudo] password for klaus: 
    [klaus@localhost rootfs_fl2440]$ cd ../jffs+ker_fl2440/linux/
    [klaus@localhost linux]$ ls
    kernel  linux-3.0  linux-3.0.tar.bz2  rootfs
    [klaus@localhost linux]$ du -sh rootfs
    12M     rootfs
    [klaus@localhost linux]$ mkfs.jffs2 -n -s 2048 -e 128KiB -d ./rootfs -o rootfs-jffs2.bin
    mkfs.jffs2: error!: open output file
                error 13 (Permission denied)
    #制作根文件系统时不进行填充
    [klaus@localhost linux]$ sudo mkfs.jffs2 -n -s 2048 -e 128KiB -d ./rootfs -o rootfs-jffs2.bin
    [klaus@localhost linux]$ du -sh rootfs-jffs2.bin
    6.3M    rootfs-jffs2.bin
    [klaus@localhost linux]$ mkfs.jffs2 -n -s 2048 -e 128KiB -d ./rootfs -o rootfs-jffs2.bin --pad=0xa00000
    mkfs.jffs2: error!: open output file
                error 13 (Permission denied)
    [klaus@localhost linux]$ sudo mkfs.jffs2 -n -s 2048 -e 128KiB -d ./rootfs -o rootfs-jffs2.bin --pad=0xa00000

## 3.2 内核配置及编译 ##

1.General setup  
减少内核大小，取消Nandflash的swap分区。

<*> Kernel .config support
    [ ] Automatically append version information to the version string
    [ ] Automatically append version i
    [ ] Support for paging of anonymous memory (swap)
    [*] Configure standard kernel features (expert users)
    [*] Embedded system

特别注意，一定要**取消initramfs的支持**，系统对initramfs的优先级最高，系统会优先启动。  
![特别注意][70]  
2.File systems  
取消没必要的文件系统支持，同样可把光盘驱动给取消了，不需要用到光盘。

< > Second extended fs support 
    < > Ext3 journalling file system support 
    < > The Extended 4 (ext4) filesystem 
    < > Kernel automounter version 4 support (also supports v3) 
    < > FUSE (Filesystem in Userspace) support 
    CD-ROM/DVD Filesystems --->
        < > ISO 9660 CDROM file system support 
        < > UDF file system support
    DOS/FAT/NT Filesystems --->
        <*> MSDOS fs support
        <*> VFAT (Windows-95) fs support添加Windows的FAT文件系统支持,U盘或SD卡中会使用
        (437) Default codepage for FAT
        (iso8859-1) Default iocharset for FAT
        <*> NTFS file system support 添加Windows的NTFS文件系统支持,U盘或SD卡中会使用
        [ ] NTFS debugging support
        [*] NTFS write support
    Pseudo filesystems --->
        <*> Userspace-driven configuration filesystem 添加sysfs伪文件系统支持
        [*] Miscellaneous filesystems --->
        <*> Journalling Flash File System v2 (JFFS2) support 添加JFFS2文件系统支持
        (0) JFFS2 debugging verbosity (0 = quiet, 2 = noisy)
        [*] JFFS2 write-buffering support
        [ ] Verify JFFS2 write-buffer reads
        [*] JFFS2 summary support (EXPERIMENTAL)
        [ ] JFFS2 XATTR support (EXPERIMENTAL)
        [ ] Advanced compression options for JFFS2其他文件系统如果不需要的话都不要选
        < > Compressed ROM file system support (cramfs) 可以取消cramfs文件系统的支持
        < > SquashFS 4.0 - Squashed file system support 可以取消SquashFS文件系统的支持
        < > ROM file system support 可以取消ROM文件系统的支持
    [*] Network File Systems --->
        <*> NFS client support
        [*] NFS client support for NFS version 3
        [*] NFS client support for the NFSv3 ACL protocol extension
        [ ] NFS client support for NFS version 4
        [*] Root file system on NFS
    
        //将其他不需要的网络文件系统都不要选
        < > NFS server support
        < > Ceph distributed file system (EXPERIMENTAL)
        < > CIFS support (advanced network filesystem, SMBFS successor)
        < > NCP file system support (to mount NetWare volumes)
        < > Coda file system support (advanced network fs)
        < > Andrew File System support (AFS) (EXPERIMENTAL)
    Partition Types --->
        [ ] PC BIOS (MSDOS partition tables) support 取消这个选项减少内核大小

3.Native language support  
语言选项就比较随意了，选择汉字就好，其他的都可以取消掉

(iso8859-1) Default NLS Option
    <*> Codepage 437 (United States, Canada)
    <*> Simplified Chinese charset (CP936, GB2312)
    <*> Traditional Chinese charset (Big5)
    <*> ASCII (United States)
    <*> NLS ISO 8859-1 (Latin 1; Western European Languages)
    <*> NLS UTF-8

选择完成后重新编译，可以查看生成后的文件大小是多少

[klaus@localhost linux-3.0]$ ./build.sh 
    [klaus@localhost linux-3.0]$ du -h linuxrom-s3c2440.bin 
    2.4M    linuxrom-s3c2440.bin

# 4. u-boot下载 #

根据内核里面配置的信息我们来配置u-boot的参数

static struct mtd_partition smdk_default_nand_part[] = {
            [0] = { 
                    .name = "mtdblock0 u-boot 1MB",
                    .offset = 0,
                    .size = SZ_1M*1, /* 0x0000000 ~ 0x0100000 */
            },
            [1] = { 
                    .name = "mtdblock1 kernel 15MB",
                    .offset = MTDPART_OFS_NXTBLK,
                    .size = SZ_1M*15, /* 0x0100000 ~ 0X1000000 */
            },
            [2] = {
                    .name = "mtdblock2 rootfs 40MB",
                    .offset = MTDPART_OFS_NXTBLK,
                    .size = SZ_1M*40,
            },
            [3] = {
                    .name = "mtdblock3 apps 80MB",
                    .offset = MTDPART_OFS_NXTBLK,
                    .size = SZ_1M*80,
            },
            [4] = {
                    .name = "mtdblock4 data 80MB",
                    .offset = MTDPART_OFS_NXTBLK,
                    .size = SZ_1M*80,
            },
            [5] = {
                    .name = "mtdblock5 backup 40MB",
                    .offset = MTDPART_OFS_NXTBLK,
                    .size = SZ_1M*40,
            }
    
    };
    
    static struct s3c2410_nand_set smdk_nand_sets[] = {
            [0] = {
                    .name           = "NAND",
                    .nr_chips       = 1,
                    .nr_partitions  = ARRAY_SIZE(smdk_default_nand_part),
                    .partitions     = smdk_default_nand_part,
            },

**参数解读**：  
jffs2根文件系统区别于initramfs文件系统，jiff2是建立在Nandflash上的根文件系统，开发板掉电不丢失，而且不像initramfs同内核绑定在一起，需要分别烧录内核和根文件系统。  
一般性经验

*  u-boot的烧录地址应该是 0，大小不超过1M。该分区对应Linux内核分区表的/dev/mtdblock0；
 *  Linux内核的烧录地址应该是0x100000(1M的偏移量处)，大小不超过15M。该分区对应Linux  
    内核分区表的/dev/mtdblock1；
 *  根文件系统镜像的烧录地址应该是0x1000000(16M的偏移量处)，大小不超过40M。该分区对应Linux内核分区表的/dev/mtdblock2；

## 4.1 内核烧录 ##

[fl2440@lingyun]# tftp 30008000 linuxrom-s3c2440.bin
    //Linux内核下载到内存地址30008000
    dm9000 i/o: 0x20000300, id: 0x90000a46 
    DM9000: running in 16 bit mode
    MAC: 00:11:22:33:44:55
    could not establish link
    Using dm9000 device
    TFTP from server 192.168.100.8; our IP address is 192.168.100.18
    Filename 'linuxrom-s3c2440.bin'.
    Load address: 0x30008000
    Loading: T ################################################################# #################################################################
             ######################################
    done
    Bytes transferred = 2461920 (2590e0 hex)
    [fl2440@lingyun]# nand erase 100000 F00000
    NAND erase: device 0 offset 0x100000, size 0xf00000
    Skipping bad block at  0x004c0000                                          
    Erasing at 0xfe0000 -- 100% complete.
    OK
    [fl2440@lingyun]# nand write 30008000 100000 400000
    //（即1M开始总共15M的空间）全部擦除
    NAND write: device 0 offset 0x100000, size 0x400000
    Skip bad block 0x004c0000
     4194304 bytes written: OK
    [fl2440@lingyun]#

## 4.2 烧录根文件系统 ##

[fl2440@lingyun]# tftp 30008000 rootfs-jffs2.bin
    dm9000 i/o: 0x20000300, id: 0x90000a46 
    DM9000: running in 16 bit mode
    MAC: 00:11:22:33:44:55
    could not establish link
    Using dm9000 device
    TFTP from server 192.168.100.8; our IP address is 192.168.100.18
    Filename 'rootfs-jffs2.bin'.
    Load address: 0x30008000
    Loading: ################################################################# #################################################################
             ################################################################# #################################################################
             ################################################################# #################################################################
             ################################################################# #################################################################
             ################################################################# #################################################################
             ################################################################# done Bytes transferred = 10485760 (a00000 hex) [fl2440@lingyun]# nand erase 1000000 2800000 //（即16M开始总共40M的空间）全部擦除 NAND erase: device 0 offset 0x1000000, size 0x2800000 Erasing at 0x37e0000 -- 100% complete. OK [fl2440@lingyun]# nand write 30008000 1000000 $filesize NAND write: device 0 offset 0x1000000, size 0xa00000 10485760 bytes written: OK [fl2440@lingyun]#

# 5. 重启 #

u-boot烧录进去后，我们可以直接重启开发板或者使用boot命令。

[fl2440@lingyun]# boot
    ... ... ...
    ~ >: mount
    rootfs on / type rootfs (rw)
    /dev/root on / type jffs2 (rw,relatime)
    proc on /proc type proc (rw,relatime)
    usbfs on /proc/bus/usb type usbfs (rw,relatime)
    tmpfs on /dev type tmpfs (rw,relatime)
    ramfs on /tmp type ramfs (rw,relatime)
    sysfs on /sys type sysfs (rw,relatime)
    devpts on /dev/pts type devpts (rw,relatime,mode=600)
    ~ >:

根文件的确挂载到了jffs2文件系统上，同时可以看看分区情况。

~ >: pwd
    /
    ~ >: ls
    apps     dev      init     mnt      rtc      tmp
    bin      etc      lib      proc     sbin     usr
    data info linuxrc root sys var
    ~ >: dmesg | grep mtdblock
    Kernel command line: console=tty0 console=ttyS0,115200 root=/dev/mtdblock2 rootfstype=jffs2 init=/linuxrc mem=64M rw noinitrd loglevel=7
    0x000000000000-0x000000100000 : "mtdblock0 u-boot 1MB"
    0x000000100000-0x000001000000 : "mtdblock1 kernel 15MB"
    0x000001000000-0x000003800000 : "mtdblock2 rootfs 40MB"
    0x000003800000-0x000008800000 : "mtdblock3 apps 80MB"
    0x000008800000-0x00000d800000 : "mtdblock4 data 80MB"
    0x00000d800000-0x000010000000 : "mtdblock5 backup 40MB"
    ~ >:

--------------------

1.  Norflash不允许有坏块，擦除比较麻烦。导致了允许出现坏块的Nandflash。 ↩

[70]: /images/20220528/3fdd43d222244e28b531288d8e40fd42.png