NoCpad provides optimized HLS-ready SystemC models of all required Network-on-Chip components, such as network interfaces and routers (including virtual channels), in order to build a scalable AMBA-compliant SoC interconnect fabric. Quality of results in terms of networking performance as well as hardware PPA matches closely that of custom RTL.
Network interfaces translate AMBA AXI-4 transactions to an internal versatible packetized protocol that is routed through a Network-on-Chip (NoC). Both coherent and non-coherent transactions are supported including AXI4, ACE network interfaces. Furthermore, ACE-Lite interfaces enable agents with no caches (such as DMA controllers or hardware accelerators) to access shareable data and participate in a mixed ACE and ACE-Lite interconnect.
Link-level communication between components is performed using Connection channels, included in Mentor's Catapult HLS HLSLibs, and MatchLib a SystemC/C++ library of commonly-used hardware functions and components.
Why does it make sense to build a NoC using HLS?
- NoC can change many times during design flow
- Changes can be structural and/or architectural
- Re-verification should be fast
- SystemC/C++ models abstract enough to be highly configurable
- Complex customizations can be easily architected
- C++ simulation is faster
- HLS constraints can produce the needed result
- Or even lead to new unexplored alternatives
- No need for re-verification
NoCpad targets agile interconnect development. The designer of the network fabric can choose across non-coherent AXI-4 interfaces or coherent ACE interfaces to compose an efficent NoC. Data transfer is handled by NoC routers that support simple wormhole or virtual-channel flow control. In all cases, contention is resolved by arbiter modules chosen from a library of various arbiter architectures.
AMBA-AXI4 interfaces :
- AXI porotocol compatibility
- All burst types
- Multiple configurable transaction IDs
- Arbitrary data lane widths, even under the same interconnect
- Narrow and unaligned transactions
- Internal packet based transport protocol
- Arbitrary internal NoC widths
- Matchlib AXI class definitions for easy interoperability
AMBA-ACE, ACE-Lite interfaces :
- ACE porotocol compatibility
- Various cache line sizes
- Interconnect's Data channels, are currenty sized depending the chosen cache line width
- HOME-Node for transaction PoS (Point-of-Serialization) and protocol management
- Multiple HOME nodes support for load balancing
- ACE-Lite support for uncached agents
- Support for the optional snoop data response
- Mixed coherent and non-coherent traffic
- Internal packet based transport protocol
- Extends Matchlib definitions for ACE support, based on the AXI paradigm
NoC Routers :
- Configurable number of Input/Output ports
- Various arbitration schemes
- Able to form arbitrary network topologies
- Two forms of link-level flow control
- Wormhole routers with Ready-Valid flow controll using Connections
- Virtual Channel based usin Connections and credit-based flow control
Library of arbiter components:
- Fixed Priority
- Round Robin
- Matrix arbiter
- Weighted Round Robin
- Deficit Round Robin
- Merged arbiter multiplexers
The codebase is based on Connections and MatchLib, and follows the similar tool/dependency versions:
gcc- 4.9.3 (with C++11)systemc- 2.3.1boost- 1.68.0catapult- 10.5a- connections - included with catapult
QuestaSim- 2019.3_1
Makefiles and synthesis scripts expect the following environment variables: (A sample bash script can be found in examples/setenv.sh)
CATAPULT_HOMESYSTEMC_HOMEBOOST_HOMEMATCHLIB_HOME
In addition, the boost and systemc library locations are expected to be in LD_LIBRARY_PATH.
cd examples/<example>
make
./sim_sc
cd examples/<example>
catapult -file go_hls_ic.tcl
Dimitris Konstantinou, Giorgos Dimitrakopoulos, Dionisis Filippas
- AMBA AHB5 network interfaces
NoCpad is licensed under the MIT License.