2014-09-22 33 views
0

我有一些与mmc写在beagleboard黑色的问题。uboot mmc写在beagleboard黑色问题

这里的问题是:

U-Boot# usb start 
(Re)start USB... 
USB0: scanning bus 0 for devices... 1 USB Device(s) found 
     scanning usb for storage devices... 1 Storage Device(s) found 
U-Boot# fatload usb 0 ${loadaddr} ${rootfs_file} 
reading rootfs.ext4 
18742272 bytes read in 12384 ms (1.4 MiB/s) 
U-Boot# mmc dev 1 
switch to partitions #0, OK 
mmc1(part 0) is current device 
U-Boot# mmc part 

Partition Map for MMC device 1 -- Partition Type: DOS 

Part Start Sector Num Sectors  UUID   Type 
    1  63    1028097   00000000-01  0c Boot 
    2  1028160   1028160   00000000-02  83 
    3  2056320   1686825   00000000-03  83 
U-Boot# mmc dev 1 2 
switch to partitions #2, OK 
mmc1(part 2) is current device 
U-Boot# mmc write $loadaddr 0x0 0x20000 

MMC write: dev # 1, block # 0, count 131072 ... MMC: block number 0xffff exceeds max(0x800) 
0 blocks written: ERROR 

那么,为什么?分区2应该是而且

U-Boot# mmc info 
Device: OMAP SD/MMC 
Manufacturer ID: fe 
OEM: 14e 
Name: MMC02 
Tran Speed: 52000000 
Rd Block Len: 512 
MMC version 4.41 
High Capacity: No 
Capacity: 1 MiB <=== ??? WHY ??? 
Bus Width: 4-bit 

感谢您的回信

弗雷德

回答

1

AFAIK “MMC写” 64MB

执行到MMC设备原始写入。它不会通过文件系统执行写入。对大多数文件系统访问命令没有“写入”支持。只有ext4似乎有“写”操作(但我没有亲自测试过)。

您执行的“mmc写入”可能覆盖了MMC分区表。

+0

嗨,分区表保存在哪里?分区表有没有偏移量? – ransh 2017-03-22 21:31:46