mtd裝置操作 jffs2

安裝mtd相關命令

手動安裝mtd-utils，根據系統自行選擇

mtd交叉編譯：

系統flash操作命令

# cat /proc/mtd dev: size erasesize name mtd0: 00080000 00020000 "boot" mtd1: 00100000 00020000 "kernel"

mtd2: 00580000 00020000 "roofs"

# flash_erase device [start] [cnt] 
# flash_erase /dev/mtd0 0×40000 5

start：起始位置。必須為0x20000(128k)的整數倍

cnt：塊數

# flash_eraseall [option] device 
# flash_eraseall -j /dev/mtd0

-j，jffs2：jffs2格式化分割槽

-q，quiet：不顯示列印資訊

# flash_eraseall -j -q /dev/mtd0 = flash_erase /dev/mtd0 0 0

新版擦除整個裝置，已建議使用flash_erase

# mount -t jffs2 /dev/mtdblock0 /mnt

掛載mtd裝置。mtdblock只用於掛載，/dev/mtd操作實際就是操作/dev/mtdblock

# flashcp # flashcp fs.jffs2 /dev/mtd0

# mtd_debug info # mtd_debug info /dev/mtd0
mtd.type = mtd_norflash
mtd.flags = 
mtd.size = 12582912 (12m)
mtd.erasesize = 131072 (128k)
mtd.oobblock = 1 
mtd.oobsize = 0 
mtd.ecctype = (unknown ecc type - new mtd api maybe?)
regions = 0
# mtd_debug read /dev/mtd2 0 100 file.dest

uboot flash操作

對nand flash對應mtd分割槽擦除時。擦除要擦除整個裝置大小；寫要寫jffs2檔案系統大小。不然資料可能會有問題，可能原因是jffs2格式寫入位置

# nand erase 0x4100000 0x200000 //擦除整個mtd分割槽2m

# nand write 0x6000000 0x4100000 0x20000 //寫入128k

uboot flash按分割槽操作

> mtd device nand0 , # parts = 4 #: name size offset mask_flags 0: bootloader 0x00040000 0x00000000 0 1: params 0x00020000 0x00040000 0 2: kernel 0x00200000 0x00060000 0 3: root 0x0fda0000 0x00260000 0 > nand erase root nand erase: device 0 offset 0x260000, size 0xfda0000 erasing at 0xffe0000 -- 100% complete. ok> nand write.jffs2 0x3000000 root nand write: device 0 offset 0x260000, size 0xfda0000

0xfda0000 bytes written: ok

filesize檔案大小

> nand write.jffs2 0x3000000 0x260000 $(filesize) nand write: device 0 offset 0x260000, size 0x15787a8 writing data at 0x17f8000 -- 100% complete.

22513576 bytes written: ok

舉例

#include #include #include #include "mtd-user.h"
int non_region_erase(int fd, int start, int count, int unlock)
}if(ioctl(fd, memerase, &erase) != 0)
erase.start += meminfo.erasesize;
}printf("done!\n");
}return 0;
}int main(int argc, char *argv)
else
struct stat st;
//check is a char device
ret = fstat(fd, &st);
if(ret < 0)
if(!s_ischr(st.st_mode))
#if 0
ret = non_region_erase(fd, 0, 1, 0);
if(ret < 0)
#endif
char *preadbuf;
int nreadbytes;
nreadbytes = info.erasesize;
preadbuf = malloc(nreadbytes);
memset(preadbuf, 0, nreadbytes);
ret = read(fd, preadbuf, 256);
printf("%s--read %d bytes from mtd\n", __func__, ret);
for(i = 0; i < ret; i++)
printf("\n");
free(preadbuf);
}

詳細操作，參考mtd原始碼mtd_debug.c

mtd裝置操作 jffs2

jffs2映象製作及掛載

jffs2映象製作和掛載

普通分割槽jffs2掛載

mtd裝置操作 jffs2

jffs2映象製作及掛載

jffs2映象製作和掛載

普通分割槽jffs2掛載

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