PULP’s CLIC extensions for fast interrupt handling
- Type: Master Thesis
- Professor: Prof. Dr. L. Benini
Alibaba has recently (October 2021) introduced a range of RISC-V processors with the Xuantie family ranging from the E902 micro-controller class core to the C910 core for servers in data centers. This also includes the XuanTie C906 core found in the Allwinner D1 single-core RISC-V processor. T-Head had open-sourced four RISC-V-based Xuantie series processor cores, namely Xuantie E902, E906, C906, and C910, as well as related software and tools . Xuantie E902 and E906 processors implement the Core-Local Interrupt Controller (CLIC) , a newly proposed RISC-V interrupt controller promising low-latency, vectored, pre-emptive interrupts to meet the needs of Real-Time embedded systems.
At IIS we recently developed an in-house CLIC IP, which is coupled with the CV32E40P processor  within the PULPissimo SoC platform. PULPissimo is a RISC-V microcontroller  developed by PULP.
The goal of this project is to:
- Study the RISC-V CLIC specifications and T-Head’s CLIC source code.
- For the latter, at IIS we have forked T-Head’s processors in our environment (Mentor Questa for RTL simulation and SW toolchain building)  to ease development/usage bring-up overhead.
- Integrate T-Head’s CLIC into PULPissimo and couple it with CV32E40P
- Verify functional correctness in simulation and measure interrupt latency
- Synthesize and compare with PULP’s CLIC (area/timing reports)
- ASIC Backend flow towards PULPissimo SoC tapeout
- 10% Literature / architecture review
- 40% RTL implementation
- 30% Backend
- 20% Evaluation
- Experience with digital design in SystemVerilog as taught in VLSI I
- Must have visited VLSI II in a previous semester or take it alongside the thesis
 https://github.com/T-head-Semi (GitHub repository)
 https://github.com/riscv/riscv-fast-interrupt/blob/master/clic.adoc (GitHub repository)
 https://github.com/bluewww/opene906 (GitHub repository)
 https://github.com/openhwgroup/cv32e40p (GitHub repository)
 https://github.com/pulp-platform/pulpissimo (GitHub repository)