Hello everybody!
I am working on a IMX-6 and i have a little problem with the MMU.
I want to write on some registers which are blocked by the MMU, so i want to disable it. I went on this page ARM Information Center and i saw that i have to use this command "MCR p15, 0, <Rd>, c3, c0, 0" but i'm not very familiar with assembler. How do i choose which domain access control register i want to modify? What i should write instead of <Rd>? And, is the value (the last field, right?) in decimal or binary?
Sorry for my english, it's not my mother tongue.
Regards
Alexandre
Hello, and thanks for your answer
I don't want to explode my board I want to put them in the sources of my kernel or my bootloader.
But i am not sure i understand your second sentence, you mean using mmap to write these registers? Because it's what i have done and it didn't worked for registers which are not writeable.
The mmap call is a user-space call which relies on the underlying (kernel-space) device node which is handling the mmap (i.e. which file descriptor) to do the right thing.
For kernel code this might be a more useful starting point:
http://www.makelinux.net/ldd3/chp-9-sect-4
HTH,
Pete