捉虫日记 0002: Can only write 7602176 bytes data to nand flash
目录 |
1 Phenomenon
Micron NAND 256MiB 3,3V 8-bit (MT29F2G08AACWP, 2048+64 bytes) 64 pages per block, 128K block size (64 * 2048) Driver got from Mindspeed
Using dd to write 20MB data into /dev/mtd0(nand) is always failed. Following is the message:
root@packet-iad:/root> dd if=jffs2-128k of=/dev/mtd0 bs=128k
dd: writing `/dev/mtd0': Input/output error
59+0 records in
58+0 records out
7602176 bytes (7.6 MB) copied, 37.587 s, 202 kB/s
2 Analysis
4/24 9:08 The root cause should be the driver's bbt control subsystem has some issue. When I modprobe the driver's module the console output following message:
root@localhost:/root> modprobe comcerto-nand
erasesize = 131072; writesize = 2048; oobsize = 64
Bad eraseblock 58 at 0x00740000
Bad eraseblock 97 at 0x00c20000
Bad eraseblock 101 at 0x00ca0000
Bad eraseblock 620 at 0x04d80000
Bad eraseblock 971 at 0x07960000
Bad eraseblock 1481 at 0x0b920000
The first bad block of this nand chip is the 59th block. So when the driver write data into the 58 blocks there is no any error. This size is 58 * 128 * 1024 = 7602176 bytes. But when the driver try to write the 59th block this operation would be failed. Because this is a bad block. Generally nand driver should avoid reading/writing bad blocks. I strange why this driver write bad blocks.
3 Solution
This problem can be solved by using nandwrite tools to write the data into nand flash. dd use the raw data write function which has no bad block checking.
4 Reference
