SPRUJ28C november 2021 – june 2023 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
This is not a new feature but a behavior update in existing feature. Previously, when broadcast mode is set (i.e. snoop filter is disabled) MSMC only sends broadcast snoop for cache hits. This new update keeps cache hit behavior as is; however, broadcast snoop is sent for cache misses as well. Note that all allocations are killed when broadcast mode is set in this new update.
Because there are no cache allocations in this mode, inclusivity is lost. Coherency is maintained as long as broadcast mode is set but dynamic change of broadcast mode from high to low (i.e. Broadcast mode enable to disable) is not supported.
System must invalidate L2 caches of all snoopable coherent masters connected to MSMC before they can disable Broadcast mode again after enabling it to maintain coherence.
This mode is expected to be used as a debug feature only, as performance is significantly impacted once this mode is enabled.