1. Padmarao Begari April 2nd, 2017
U-Boot Port for RISC-V
Padmarao Begari
April 2nd, 2017
© 2017 Microsemi Corporation

2. © 2017 Microsemi Corporation
Overview
U-Boot – In General
Microsemi RISC-V Soft Processor
Microsemi RISC-V U-Boot
Tool chain
© 2017 Microsemi Corporation

3. © 2017 Microsemi Corporation
U-Boot – In General
Open source, cross-platform boot loader
Source code available at
Supports many CPU architectures and platform types
ARC, ARM, AVR32, Blackfin, m68k, Microblaze, MIPS, NDS32, NIOS, Openrisc, PowePC, Sparc, x86
adp-ag101p, at91sam9260ek, bf506f-ezkit, cobra5272, da8xxevm, el6x, mpc8641hpcn, pic32mzda, panda, ti816x, zynq-zc706…etc.
© 2017 Microsemi Corporation

4. Microsemi: RISC-V Soft Processor
Features
Based on the E31 Coreplex Core by SiFive
Supports the RISC-V standard RV32IM ISA
Provides a single hardware thread (hart)
Machine-mode privileged architecture
Integrated 8KB I-Cache and D-Cache
Two external AXI interfaces for IO and memory
Support up to 31 programmable interrupts
Debug unit with a JTAG interface
Low-mid range Microcontroller applications
© 2017 Microsemi Corporation

5. Microsemi RISC-V U-Boot Implementation
RISC-V reset vector at 0x on SmartFusion2 device
DRAM is on board DDR3 memory at 0x
© 2017 Microsemi Corporation

6. Microsemi RISC-V U-Boot Implementation…
The U-boot version is used for RISC-V port.
Dynamic relocation option(-pie) with linker.
RISC-V uses the RELA relocation format.
Ported UART, SPI and Timer drivers.
© 2017 Microsemi Corporation

7. © 2017 Microsemi Corporation
Tool chain
Eclipse based Integrated Development Environment
Microsemi RISC-V SoftConsole v5.0.
Cross compiler tool
SiFive riscv32-unknown-linux-gnu-gcc v6.1.0
Host PC
Ubuntu 14.04L
JTAG
Microsemi FlashPro5
Board
Microsemi SmartFusion2 Advance Development Kit.
Serial Terminal
Tera term – Windows
Minicom - Linux
© 2017 Microsemi Corporation

8. Microsemi RISC-V SoftConsole
SoftConsole v
Download link available in github Microsemi-FPGA/SoftConsole
Supported platforms
Ubuntu / LTS Desktop 32 and 64 bit
CentOS/Red Hat Enterprise Linux 6.8/7.2 Desktop 32 and 64 bit
OpenSuse Leap 42.1 [Gnome/Kde desktop] 64 bit
Platforms yet to be supported
Linux distributions/versions other than those listed above
Microsoft Windows
Virtual machines
© 2017 Microsemi Corporation

9. Microsemi RISC-V U-Boot on GitHub
Link
Tested on Microsemi SmartFusion2 Advance Dev Kit
Easy to use on other Microsemi platforms
© 2017 Microsemi Corporation

10. © 2017 Microsemi Corporation
Further Enhancement
Launch Operating System
© 2017 Microsemi Corporation

11. © 2017 Microsemi Corporation
Conclusion
Microsemi RISC-V Soft Processor
Microsemi RISC-V U-Boot Implementation
Tool Chain used
© 2017 Microsemi Corporation

12. © 2017 Microsemi Corporation
Any questions please
© 2017 Microsemi Corporation

13. © 2017 Microsemi Corporation
Bio
Padmarao Begari has been working as Staff Engineer – Firmware at Microsemi SoC product group. He works on firmware drivers for Microsemi IP cores, system software and OS porting. He has more than 10 years experience in embedded firmware development. Padmarao holds a bachelor’s degree in Electrical and Electronics Engineering from Osmania University.
© 2017 Microsemi Corporation