Hi All, We are interested in adopting EBBR as the boot specification for the embedded RISC-V platforms. We firmly believe that EBBR is a very well defined specification for boot requirement and there is no need for reinventing the wheel for RISC-V. Hence, this is a thread to discuss all the requirements for adding RISC-V to EBBR. Here is my current understanding. Please correct me if I am wrong.
Logistic Requirement: 1. As per the contribution guidelines[1], patches should be sent to boot-architecture@lists.linaro.org. and the specification will be hosted under "ARM-software" Github. I am hoping that introducing RISC-V related changes are okay with the current maintainers. 2. The specification is licensed under Creative Commons. The RISC-V related changes will refer to some of the RISC-V specifications as well. AFAIK, there shouldn't be an issue with that. 3. It should be okay to add other copyrights in addition to "Arm Limited and Contributors".
Technical Requirement: 1. Software status: a. UEFI support for RISC-V Linux kernel is already available in the mailing list[2]. The targeted upstream merge is the 5.10 merge window. b. U-Boot already supports UEFI for RISC-V. c. EDK2 upstreaming is currently under progress [3] as well.
Is it okay to start sending patches for EBBR RISC-V related changes now or do we need to wait for EDK2 and Linux kernel patches to be available upstream ?
2. RISC-V related sections in EBBR a. UEFI: Currently, RISC-V doesn't support a EFI_RESET_SYSTEM boot service as firmware doesn't have a standard way to reset the system. There is a proposal to add a system reset function to Supervisor Binary Specification(SBI) which can be mapped to EFI_RESET_SYSTEM by the firmware. Apart from that, I believe RISC-V supports all UEFI boot and run time services mandated by EBBR. Is it a blocker for RISC-V EBBR compatibility? b. RISC-V Multiprocessor Startup Protocol: This section will contain the details of booting protocol for RISC-V and mandatory RISC-V specifications that need to be implemented. c. Firmware Storage: AFAIK, RISC-V platforms are already compatible with this.
Please let me know if I missed something or oversimplified any requirement. We want to make RISC-V compatible with EBBR sooner than later and ready work on any missing pieces if any.
[1] https://github.com/ARM-software/ebbr/blob/master/CONTRIBUTING.rst [2] https://lkml.org/lkml/2020/8/19/1252 [3] https://edk2.groups.io/g/devel/message/63831?p=,,,20,0,0,0::Created,,RISC-V,... [4] https://lists.riscv.org/g/tech-unixplatformspec/message/49?p=,,,20,0,0,0::re...
-- Regards, Atish