SPI Collator wires
The SPI Collator wires can be extended to create other functions.
By default, the asserted level of a SPI is active-HIGH, as with previous Arm GIC implementations. However, each SPI can be either inverted or synchronized, or both, using the parameters gic600_<config_name>_SPI_INV[n] and gic600_<config_name>_SPI_SYNC[n], where:
- SPI_INV[n] == 1 = inverter enabled.
- SPI_SYNC[n] == 1 = synchronizer enabled.
- [n] = SPI_ID - 32.
Each SPI Collator wire has corresponding wires after the synchronizer or capture flop that can be used to create pulse extenders for edge-triggered interrupts that cross clock domains. If SPI_INV is set to 1, then the wire after the synchronizer is inverted with respect to the input.