A StreamID is used to map the incoming transaction to a context by using the stream mapping table. The characteristics of the StreamID are as follows:
The width of the StreamID is selected during the MMU-500 configuration.
You must specify the StreamID on a dedicated AXI sideband signal. Select the
StreamID - width of the sideband signal parametervalue from the range 1-10 bits. Dedicated sideband signals are used for read and write transactions.
For more information about StreamID signals, see Sideband signals.
The StreamID width in the TCU is a constant 15 bits. The StreamID from each TBU is zero-extended to form a 10-bit field appended to a 5-bit TBU ID field, making it 15 bits wide.
The StreamID presented to each TBU is not unique, and happens at the TCU. If the StreamID presented to each TBU is already unique, and the TBU ID addition is not required, then you must ensure that the TBU ID field is masked in the SMR.
See the ARM® System Memory Management Unit Architecture Specification for more information on StreamID-to-context mapping.