通过UBI文件系统烧写flash

appfs文件太大，虽然可以在uboot通过tftp传输来烧写。但是同样也可以通过ubi文件系统来做这件事情。

Nand分区划分如下：

device nand0 <nx_2017>, # parts = 4

#: name size offset mask_flags

0: kernel 0x00a00000 0x00100000 0

1: root 0x00f00000 0x00a00000 0

2: appfs 0x05000000 0x01900000 0

3: datac 0x01700000 0x06900000 0

板子配置nfs启动以后，先将分区格式化：

# ubiformat /dev/mtd2 -y

ubiformat: mtd2 (nand), size 83886080 bytes (80.0 MiB), 640 eraseblocks of 131072 bytes (128.0 KiB), min. I/O size 2048 bytes

libscan: scanning eraseblock 639 -- 100 % complete

ubiformat: 511 eraseblocks have valid erase counter, mean value is 0

ubiformat: 129 eraseblocks are supposedly empty

ubiformat: warning!: only 511 of 640 eraseblocks have valid erase counter

ubiformat: mean erase counter 0 will be used for the rest of eraseblock

ubiformat: use erase counter 0 for all eraseblocks

ubiformat: formatting eraseblock 639 -- 100 % complete

然后将这个分区attach到ubi文件系统中：

# ubiattach /dev/ubi_ctrl -m 2

UBI: attaching mtd2 to ubi0

UBI: physical eraseblock size: 131072 bytes (128 KiB)

UBI: logical eraseblock size: 126976 bytes

UBI: smallest flash I/O unit: 2048

UBI: VID header offset: 2048 (aligned 2048)

UBI: data offset: 4096

UBI: attached mtd2 to ubi0

UBI: MTD device name: "appfs"

UBI: MTD device size: 80 MiB

UBI: number of good PEBs: 640

UBI: number of bad PEBs: 0

UBI: max. allowed volumes: 128

UBI: wear-leveling threshold: 4096

UBI: number of internal volumes: 1

UBI: number of user volumes: 0

UBI: available PEBs: 630

UBI: total number of reserved PEBs: 10

UBI: number of PEBs reserved for bad PEB handling: 6

UBI: max/mean erase counter: 0/0

UBI: image sequence number: 1404847517

UBI: background thread "ubi_bgt0d" started, PID 695

UBI device number 0, total 640 LEBs (81264640 bytes, 77.5 MiB), available 630 LEBs (79994880 bytes, 76.3 MiB), LEB size 126976 bytes (124.0 KiB)

然后创建一个volume，名字为你的mtd分区名

# ubimkvol /dev/ubi0 -N appfs -m

Set volume size to 79994880

Volume ID 0, size 630 LEBs (79994880 bytes, 76.3 MiB), LEB size 126976 bytes (124.0 KiB), dynamic, name "appfs", alignment 1

然后mount这个volume到指定位置

# mount -t ubifs ubi0:appfs /mnt/
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