openc910 VS rpi-open-firmware

> I'm pretty sure that SiFive isn't allowed to sell their RISC-V core designs to any Chinese company already.

The JH7110 SoC from the Chinese firm Starfive uses SiFive's U74 core. Eswin, also Chinese uses SiFive's P550 core in their upcoming EIC7700 SoC.

> All Chinese RISC-V core designs have been proprietary designs thus far.

There is the OpenC910 [1] and OpenXiangShan [2].

[1] https://github.com/T-head-Semi/openc910

Note that the C910 CPU cores used in this chip are in fact open source:

https://github.com/T-head-Semi/openc910

(C920 is just C910 plus RVV draft 0.7.1 vector unit which pretty much no software uses anyway, sadly)

The Milk-V Pioneer uses a C910 CPU, which has been open sourced by t-head: https://github.com/T-head-Semi/openc910

More precisely, a Chinese university assembled a rack containing 48 [1] commercially available SBCs [2], each with a Chinese-designed and made SG2042 SoC with 64 C910 CPU cores. The C910 was designed in China in 2018/19 and open-sourced in October 2021, on Microsoft's github site.

https://github.com/T-head-Semi/openc910

The SG2042 is the most powerful RISC-V SoC available today.

In which direction is the technology transfer going?

[1] or possibly 24 dual-socket boards, shown at the RISC-V Summit China in August

[2] get your own here https://www.crowdsupply.com/milk-v/milk-v-pioneer

For "coming down the pipeline" they're essentially free.

Today, the c910 is an Apache 2, hardware proven out of order core on GitHub here https://github.com/T-head-Semi/openc910 a little slower than an RPi3's core.

Here is the source code* for the CPU:

https://github.com/T-head-Semi/openc910

* AFAIK they didn't opensource the pre ratification vector extension implementation they ship with the taped out chip.

The source RTL for the roughly Arm A72-equivalent cores used in this were open-sourced several years ago.

https://github.com/T-head-Semi/openc910

The same cores are used in the 64 core SG2042 workstation/server SoC.

It's a shame, because it was the best design from ARM; they're now focusing on Cortex-A7x and Cortex-X, which aren't anywhere as power efficient[0].

Meanwhile, their revised Cortex-A57 has been surpassed in performance/power/area by several RISC-V microarchitectures, such as SiFive's U74[1], used in the VisionFive2 and Star64, or even the open source XuanTie C910[2][3].

0. https://www.youtube.com/watch?v=s0ukXDnWlTY

1. https://www.sifive.com/cores/u74

2. https://xrvm.com/cpu-details?id=4056743610438262784

3. https://github.com/T-head-Semi/openc910

> Please correct me if I'm wrong.

My memory told me it was the GPU that needed the blobs. So I asked at DDG

https://duckduckgo.com/?t=ftsa&q=binary+blobs+and+the+Raspbe...

Turned up this: https://wiki.debian.org/RaspberryPi and it says...

> All Raspberry Pi models before the 4 (1A, 1B, 1A+, 1B+, Zero, Zero W, 2, 3, Zero 2 W) boot from their GPU (not from the CPU!), so they require a non-free binary blob to boot

So the 4 (and I suppose the 5, if it ever actually comes...)

Goes on to say:

> Since then, Broadcom publicly released some code, licensed as 3-Clause BSD, to aid the making of an open source GPU driver. The "rpi-open-firmware" effort to replace the VPU firmware blob started in 2016. See more at https://news.ycombinator.com/item?id=11703842 . Unfortunately development of rpi-open-firmware is currently (2021-06) stalled.

So there you are. Not wrong, are you, but not strictly correct, depending on "...to run properly" definition

https://github.com/librerpi/rpi-open-firmware has updates 3-months ago

many of those demos work on the the entire pi model range

pi3 support is only broken due to arm side problems, which could be fixed by just using a different bootloader

and the https://github.com/librerpi/rpi-open-firmware codebase can already boot linux headlessly on both pi2 and pi3, it uses a different arm bootloader

Yes, and some folks are reverse engineering their stuff:

https://github.com/librerpi/rpi-open-firmware/

rpi-open-firmware: open-source VPU side bootloader for Raspberry Pi\ (35 comments)

There is work being done on the RPi4, for example the SHA1 HMAC protecting the boot on the RPi4 had to be cracked (and was easily), I hear future versions have RSA signing support, so the proprietary firmware might become mandatory at some point.

https://github.com/librerpi/rpi-open-firmware/blob/master/do...

There is a project to create an open source version of the proprietary GPU firmware that boots into the ARM processor:

https://github.com/librerpi/rpi-open-firmware

I note that even the Raspberry Pi is moving towards locked down devices, the RPi4 has an (easily cracked) HMAC blocking booting into the open source firmware and I hear more recent hardware editions have RSA signing support in the bootrom code.

https://github.com/librerpi/rpi-open-firmware/blob/master/do...