SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The C66x corepac submits writes denoted as either “cacheable” or non-cacheable. Write accesses that are non-cacheable will be submitted as interconnect (L3_MAIN) non-posted writes; whereas write accesses that are cacheable are submitted as interconnect posted writes. An exception for the cache writes to L3_MAIN is that in the case of a cache block write-back operation (when actual cache evict busrts are actually issued towards L3_MAIN connected memory), a non-posted write is submitted.
In order to provide a safety net for interconnects that may do aggressive reordering, a memory-mapped register SW control is provided - DSP_SYS_BUS_CONFIG[24] NOPOSTOVERRIDE. When set, this results in all write commands being issued as non-posted. This bit defaults to set, and thus the default behavior is for non-posted writes to be used exclusively.