SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
MSMC supports hardware cache coherence between CPU cache-coherent masters and peripherals accessing MSMC through the system slave ports for shared SRAM and DDR data range spaces. Hardware coherence support abstracts away the cache memory systems of supported components from software, simplifying software implementation.
MSMC does not support memory coherence for the following spaces:
To stay coherent with each other, caches inside coherent masters typically track more states than the traditional valid/dirty combinations. MSMC uses the ACE coherence protocol which supports these five MOESI states:
In order to maintain coherence between cached masters, MSMC can initiate requests to coherent masters for shared regions of memory. These requests are referred to as "snoop requests".
The following example demonstrates how coherence is maintained between DMA and CPU, when DMA writes to shareable memory space.
The following example demonstrates how coherence is maintained between DMA and CPU, when DMA reads from shareable memory space.