SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
A special case is when a TLB should go through a lookup but is disabled through the PVU_CHAIN_j[31] EN bit, or the entire PVU is disabled through the PVU_ENABLE[0] EN bit. If a lookup is requested when the TLB or PVU is disabled, then the transaction will pass and no translation will occur (output address is the same as the input address). Also, if the atype=1 then it will change to atype=0 on the output so that the resulting bypass transaction does not get routed right back to the PVU. Any other atype value will be maintained on the output. Any entries set in the disabled TLB are ignored as well as the chaining setting (described in Section 8.3.2.12) is also ignored, so once a disabled TLB is used then the chain is ended. Software must take care to not include any disabled TLBs in chains that must be fully searched – if a TLB must be disabled then the chain must be updated first to skip over that TLB and any virtIDs that directly map to that TLB initially must not be used.