mtd命令及制作ubi镜像做根文件系统

在linux2.6.28后才加入对ubifs的支持

1 查看nand分区

root@ubuntu:~# cat /proc/mtd

dev: size erasesize name

mtd0: 00020000 00020000 "U-Boot-min"

mtd1: 00240000 00020000 "U-Boot"

mtd2: 00020000 00020000 "U-Boot Env"

mtd3: 00440000 00020000 "Kernel"

mtd4: 1f400000 00020000 "File System"

mtd5: 00540000 00020000 "Reserved"

root@ubuntu:~# cat /proc/partitions

major minor #blocks name

31 0 128 mtdblock0

31 1 2304 mtdblock1

31 2 128 mtdblock2

31 3 4352 mtdblock3

31 4 512000 mtdblock4

31 5 5376 mtdblock5

root@ubuntu:~#

2、查看mtd4的信息

root@ubuntu:~# mtdinfo -m 4 -u

mtd4

Name: File System

Type: nand

Eraseblock size: 131072 bytes, 128.0 KiB

Amount of eraseblocks: 4000 (524288000 bytes, 500.0 MiB)

Minimum input/output unit size: 2048 bytes

Sub-page size: 512 bytes

OOB size: 64 bytes

Character device major/minor: 90:8

Bad blocks are allowed: true

Device is writable: true

Default UBI VID header offset: 512

Default UBI data offset: 2048

Default UBI LEB size: 129024 bytes, 126.0 KiB

Maximum UBI volumes count: 128

root@ubuntu:~# mtdinfo -m 2 -u

或

root@ubuntu:~# mtdinfo /dev/mtd4

mtd2

Name: U-Boot Env

Type: nand

Eraseblock size: 131072 bytes, 128.0 KiB // FLASH物理擦除块大小

Amount of eraseblocks: 1 (131072 bytes, 128.0 KiB)

Minimum input/output unit size: 2048 bytes 1）nor flash:通常是1个字节 2）nand falsh：一个页面

Sub-page size: 512 bytes //对于nand flash来说，子页大小

OOB size: 64 bytes

Character device major/minor: 90:4

Bad blocks are allowed: true

Device is writable: true

Default UBI VID header offset: 512

Default UBI data offset: 2048

Default UBI LEB size: 129024 bytes, 126.0 KiB //逻辑擦除块大小

Maximum UBI volumes count: 128

mtd4大小为500MiB,擦除单元大小(一般即为块大小)为128KiB，名字是"NAND simulator partition 0"。 NandFlash

擦除是以块(block)为单位，读写是以页(page)为单位。

3 root@ubuntu:~# ls -lah /dev/mtd*

crw------- 1 root root 90, 0 Jan 1 00:00 /dev/mtd0 //字符设备

crw------- 1 root root 90, 1 Jan 1 00:00 /dev/mtd0ro

crw------- 1 root root 90, 2 Jan 1 00:00 /dev/mtd1

crw------- 1 root root 90, 3 Jan 1 00:00 /dev/mtd1ro

crw------- 1 root root 90, 4 Jan 1 00:00 /dev/mtd2

crw------- 1 root root 90, 5 Jan 1 00:00 /dev/mtd2ro

crw------- 1 root root 90, 6 Jan 1 00:00 /dev/mtd3

crw------- 1 root root 90, 7 Jan 1 00:00 /dev/mtd3ro

crw------- 1 root root 90, 8 Jan 1 00:00 /dev/mtd4

crw------- 1 root root 90, 9 Jan 1 00:00 /dev/mtd4ro

crw------- 1 root root 90, 10 Jan 1 00:00 /dev/mtd5

crw------- 1 root root 90, 11 Jan 1 00:00 /dev/mtd5ro

brw-rw---- 1 root disk 31, 0 Jan 1 00:00 /dev/mtdblock0 //块设备，与mtd0对应

brw-rw---- 1 root disk 31, 1 Jan 1 00:00 /dev/mtdblock1

brw-rw---- 1 root disk 31, 2 Jan 1 00:00 /dev/mtdblock2

brw-rw---- 1 root disk 31, 3 Jan 1 00:00 /dev/mtdblock3

brw-rw---- 1 root disk 31, 4 Jan 1 00:00 /dev/mtdblock4

brw-rw---- 1 root disk 31, 5 Jan 1 00:00 /dev/mtdblock5

root@ubuntu:~#

4.

关于mtd工具集的安装

sudo apt-get install mtd-utils

UBI文件系统镜像文件的制作

@ubuntu:~$ sudo mkfs.ubifs -r targetfs -m 2048 -e 129024 -c 3900 -o ubifs.img

@ubuntu:~$ sudo ubinize -o ubi.img -m 2048 -p 128KiB -s 512 ubinize.cfg

关于mkfs.ubifs参数的算法

-m minimum I/O unit size

-e, --leb-size=SIZE logical erase block size

-c maximum logical erase block count

-x compression type - "lzo", "favor_lzo", "zlib" or "none" (default: "lzo")

-p size of the physical eraseblock of the flash this UBI image is created for in bytes

wear_level_reserved_blocks is 1% of total blcoks per device

*logical_erase_block_size* is physical erase block size minus 2 pages for UBI

Block size = page_size * pages_per_block

physical blocks on a partition = partition size / block size

Logical blocks on a partition = physical blocks on a partitiion - reserved for wear level

File-system volume = Logical blocks in a partition * Logical erase block size

关于参数可以参考attach的命令输出：

root@ubuntu:~# ubiattach /dev/ubi_ctrl -m 4 -d 0

UBI device number 0, total 4000 LEBs (516096000 bytes, 492.2 MiB), available 0 LEBs (0 bytes), LEB

size 129024 bytes (126.0 KiB)

root@ubuntu:~#

ubinize.cfg文件

[ubifs]

mode=ubi

image=ubifs.img

vol_id=0

vol_size=450MiB

vol_type=dynamic

vol_alignment=1

vol_name=rootfs

vol_flags=autoresize

5. UBI文件系统镜像在Linux下的烧写

flash_eraseall /dev/mtd4

ubiformat /dev/mtd4 -s 512 -f /xxx/ubi.img

6、 UBI文件系统镜像在U-BOOT下的烧写

//load ubi image to RAM

tftp ubi.img

//erase MTD4 nand space

nand erase 0x6c0000 0xc820000

//write image to nand

nand write.i 0x81000000 0x6c0000 0xxxxx(image size)

7. UBI文件系统镜像在Linux下的挂载和卸载

挂载

ubiattach /dev/ubi_ctrl -m 4 -d 0

mount -t ubifs ubi0_0 /mnt/ubi

卸载

umount /mnt/ubi

ubidetach -d 0

8、使用ubi做根文件系统

需要在bootargs中设置如下信息：

root=ubi0:rootfs ubi.mtd=4 rootfstype=ubifs

配置linux内核

配置的时候选上

1)Device Drivers --->Memory Technology Device (MTD) support --->UBI - Unsorted block images --->Enable UBI

2)File systems --->Miscellaneous filesystems --->UBIFS file system support

这样我们的内核就支持UBIFS文件系统了