If a data is stalled inside asynchronous bridge because of back
pressure, it may be accepted multiple times, creating pointer
misalignment that will corrupt next transfers on that data path
until next reset of the system (No recovery procedure once the
issue is hit, the path remains consistently broken). Async bridge
can be found on path between MPU to EMIF and MPU to L3 interconnect.
This situation can happen only when the idle is initiated by a
Master Request Disconnection (which is trigged by software when
executing WFI on CPU).
The work-around for this errata needs all the initiators connected
through async bridge must ensure that data path is properly drained
before issuing WFI. This condition will be met if one Strongly ordered
access is performed to the target right before executing the WFI.
In MPU case, L3 T2ASYNC FIFO and DDR T2ASYNC FIFO needs to be drained.
IO barrier ensure that there is no synchronisation loss on initiators
operating on both interconnect port simultaneously.