SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The default configuration of MPAX registers provides a 32-bit view of system memory on L3_MAIN.
In summary, each MPAX segment (mentioned above) is programmed with a starting virtual base address, segment sizes from 4 GiB down to 4 KiB, replacement address (i.e., physical address); and permission attributes. Provided that DSP_MMU0 can be used to perform address translation, in most cases the replacement address will equal the base address (i.e., virtual == physical from DSP C66x CorePac perespective).
The system level implementation of MPAX logic allows the C66x CPU to change permission without being required to flush the cache.
The C66x CPU subsystem relies on the MPAXn.PERM field to properly configure the permissions for remote address ranges. The MDMA.rperm[6:0] signals are tie-off to a fixed value of 0x7F on the DSP C66x CorePac boundary.