December 17, 2025

RK3399 - More on the address map and the MMU

We know that we have ram in almost all of the 4G address space. The last 128M is device IO registers.

We have RAM from 0000_0000 to F7ff_ffff.

The question now is how that ram is used by ATF and by U-boot. 

The MMU tablesare at F7ff_0000
The vectors are at F7f1_0000
The SP from U-boot is F5F0_3970
At this point I don't know where U-boot itself is. And I don't know where ATF (namely BL31) is located.

The vectors themselves must point to code in U-boot. I have dumped the vectors, but will need to disassemble them before I can make any sense of them.

Have any comments? Questions? Drop me a line!

Tom's electronics pages / tom@mmto.org