请问我能通过修改配置文件的方式来默认关闭MMU和D－Cache吗？

应该可以，试试在openocd.cfg里调用脚本，比如：
script ....

这个。。。我是新手。。。。
我在openocd.cfg加入了
script /work/eclipse_projects/closeMMU.sh
widon@widon-laptop:~$ cat /work/eclipse_projects/closeMMU.sh
arm920t cp15 2 0

widon@widon-laptop:~$ openocd -f /work/eclipse_projects/openocd.cfg
Open On-Chip Debugger 1.0 (2008-10-04-09:26) svn:717
$URL: svn://svn.berlios.de/openocd/trunk/src/openocd.c $
Info:    options.c:50 configuration_output_handler(): jtag_speed: 0, 0
Info:    options.c:50 configuration_output_handler(): Open On-Chip Debugger 1.0 (2008-10-04-09:26) svn:717
Info:    options.c:50 configuration_output_handler(): fast memory access is enabled
Info:    options.c:50 configuration_output_handler(): target must be stopped for "cp15" command
Info:    jtag.c:1389 jtag_examine_chain(): JTAG device found: 0x0032409d (Manufacturer: 0x04e, Part: 0x0324, Version: 0x0)
Info:    server.c:78 add_connection(): accepting 'telnet' connection from 0
User:    target.c:957 target_arch_state(): target state: running
User:    target.c:957 target_arch_state(): target state: halted
User:    arm920t.c:574 arm920t_arch_state(): target halted in ARM state due to debug request, current mode: Supervisor
cpsr: 0x40000013 pc: 0xc009585c
MMU: enabled, D-Cache: enabled, I-Cache: enabled

widon@widon-laptop:~$ telnet localhost 4444
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Open On-Chip Debugger
> poll
target state: running
> halt
target state: halted
target halted in ARM state due to debug request, current mode: Supervisor
cpsr: 0x40000013 pc: 0xc009585c
MMU: enabled, D-Cache: enabled, I-Cache: enabled
>
好象不行罗哦:Q