1.1 About the CCN-502 Cache Coherent Network
The CCN-502 is a scalable coherent interconnect based on the AMBA 5 CHI architecture. It is designed for use in high-end networking and enterprise compute systems.
The CCN-502 combines interconnect and coherency functions
into a single module. It provides the following external interfaces:
- Four fully coherent CHI ports for connection to CHI fully coherent devices.
- Two (6XP/2HNF configuration) or four (8XP/4HNF configuration) CHI slave-node ports or AXI4 master ports for connection to CHI or AXI4 memory controllers.
- One ACE-Lite/AXI4 master port for connection to the slave
Input/Output (I/O) subsystem.
- Nine ACE-Lite/ACE-Lite+DVM/AXI4 slave ports for connection to the
master I/O subsystems.
A system containing the CCN-502 contains the following
- Fully-coherent Requesting Node (RN-F)
- A fully-coherent master device.
- I/O-coherent Requesting Node (RN-I) bridge
- An I/O-coherent master device. This is a native CHI bridge acting as an RN-I proxy for one or more
non-native CHI devices located behind the RN-I bridge.
- Fully-coherent Home Node (HN-F)
- A device that is a home node for a region of memory, accepting coherent requests from RN-Fs and
RN-Is, and generating snoops to all applicable RN-Fs in the system as required to support the
- I/O Home Node (HN-I)
- A device that acts as a home-node for the slave I/O subsystem, mainly responsible for ensuring
proper ordering of requests sent into the slave I/O subsystem.
- Fully-coherent Slave Node (SN-F)
- A fully-coherent device that communicates with one or more HN-Fs that is solely a recipient of CHI
commands, limited to fulfilling simple read and write commands.
- Miscellaneous Node (MN)
- A device that is responsible for handling barriers, Distributed Virtual Memory (DVM)
operations, configuration accesses, error reporting and signaling, interrupt generation, and
debug-support features. The MN shares a single device port with the HN-I.
- DVM Requesting Node (RN-D)
- An I/O-coherent master device that can accept DVM messages on the snoop channel.