openc906 VS linux

Datasheet: https://github.com/milkv-duo/hardware

Reading the datasheet, it looks like there is one C906 cpu with 700 Mhz without the the vector extension and one C906 cpu at 1Ghz with rvv 0.7.1. The C906 design has been opensourced and is available here: https://github.com/T-head-Semi/openc906

The C906 supports rv64gc with optimal rvv 0.7.1 with a vlen of 128, but a 256 wide ALU.

They list H.264/H.265 support, but I don't think it's a standardized extension.

But see my other comment about using the pre ratification vector extension:

Note that the implementations themselves are often not open source, for example a random person won't be able to get the sources of these SiFive cores anywhere. As of a open-source core from a commercial company, the OpenC906 is an open-source implementation provided by T-Head, but the vector unit is not included in the open source version and thus cannot enabled.

Still not free hardware, real chads use XuanTie C906 based MangoPi MQ-PRO!

Try and see if you can find any stolen code here[0] or here[1].

Cheers.

0. https://github.com/T-head-Semi/openc906

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

I wouldn't quite say that's the case. Two of the three full Linux capable RISC-V SoC releases this year are using open source CPU cores. The BL808 and the Allwinner D1 both use T-Head CPU cores that are available on GitHub https://github.com/T-head-Semi/openc906 . The JH7110 in the VisionFive2 and Star 64 does use a closed CPU core however.

For example, let's take the ClockworkPi uConsole. It uses an Allwinner D1 chip as it's main processor which has a seemingly auditable XuanTie C906 which could theoretically be verified if one opened up a few chips.

For an example of what CPU core RTL looks like look no further than: https://github.com/T-head-Semi/openc906

For example, for the record, the open source C906 RTL, found here https://github.com/T-head-Semi/openc906 doesn't even have the vector files in there.

It has hardware IRQ muxing, this is the driver (https://github.com/smaeul/linux/commit/16eafe2078ebe9306d095...), we already use if for booting off sdcard/ethernet/usb etc..

I was able to compile the default Linux kernel (from https://github.com/smaeul/linux) and boot it on Nezha board.

Cloned and built the linux kernel with defconfig from https://github.com/smaeul/linux/tree/d1/all. Used riscv64-linux-gnu-gcc 9.4.0 that I installed using apt on Ubuntu for cross compiling.

I saw some instructions are available to build the Linux kernel for D1 at https://linux-sunxi.org/Allwinner_Nezha and https://andreas.welcomes-you.com/boot-sw-debian-risc-v-lichee-rv/ but they use a custom Linux source at https://github.com/smaeul/linux

I got about as far as before your first edit, but gave up before trying. It's cool that you found the fork point. Looks like quite a lot of work to unpick. Did you see the https://github.com/smaeul/linux/commits/riscv/d1-wip in the other thread, also seems worth looking at.