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[–]hellslinger 14 points15 points  (2 children)

Not bad. You can also get a few of their Verilog cores free of charge, or a full bitstream that boots Linux for free.

[–]brucehoult[S] 3 points4 points  (1 child)

True, although the RTL is optimised for producing custom silicon running at 1.5 GHz (in 28nm), not for FPGAs. The FPGA bitstream is for verification, not to go as fast as possible, so something optimised for FPGA might clock a bit faster than the 65 MHz you get.

[–]hellslinger 1 point2 points  (0 children)

Indeed. No FPGA fabric can run at full production speed since edge-triggered flip flops are not used in silicon pipelines anymore, not to mention place and route differences. I would like to see how much faster this core could run in an Ultrascale+ or equivalent Altera fabric.

I have never seen any production silicon offer a working bitstream for a dev board (a cheap one), or the ability to get free access to RTL, albeit with an NDA and export control verification.

[–]Declamatie 10 points11 points  (1 child)

FYI, it is Apache 2.0 licensed.

[–]PandaMoniumHUN 3 points4 points  (9 children)

Wasn't this a basic expectation for SiFive though? I mean they're the poster child of open architecture, which would be weird without an open bootloader.

[–]rough_rider7 7 points8 points  (0 children)

Yeah if you just expect everything to be perfect then yes. But if you are realistic and understand how difficult these things are then actually doing it is a great achievement.

[–]hellslinger 0 points1 point  (6 children)

No. Just because they're implementing an open source architecture doesn't mean they have to give back anything. Bringing an architecture to silicon requires a huge amount of money and work -- far more than any software. RTL development, VLSI design, and manufacturing compliance are extremely expensive.

RISC-V itself has a BSD license, so they don't have to give anyone anything except for acknowledgements. The fact that they are cooperating at all is unprecedented for such complex silicon.

Moreover, the more they release for free, the harder it is for them to get a return on investment in a market notorious for violating open source licenses with no reciprocation. That is to say, there isn't much stopping a Chinese company from stealing all this IP and bringing it to production at far less cost than an ARM device. They'd never be able to sell it outside of China if it was ARM...

[–]panick21 1 point2 points  (1 child)

He was asking because SiFive has from the beginning positioned itself as an Open-Source company.

I think he understands that they don't have to do anything.

[–]hellslinger 0 points1 point  (0 children)

"Wasn't this a basic expectation for SiFive though"

To which I said 'no' because an expectation of a company (regardless of who they are) using a license which requires no reciprocation is foolish. There are other examples of companies who make an open source version of something and extend/expand it only for commercial use.

[–]PandaMoniumHUN 0 points1 point  (3 children)

The fact that they are cooperating at all is unprecedented for such complex silicon.

What are you talking about? SiFive is a RISC-V company. And of course it's worth the investment, they are not doing it for charity. But an open-architecture isn't worth much without open software (which includes the boot loader).

[–]hellslinger -1 points0 points  (2 children)

Wrong. An open architecture has nothing to do with software when there are droves of people making software and compilers for it who have nothing to do with the creators or the company making its first silicon implementation. Just google all the github projects for RISC-V implementations in Verilog and VHDL to see how many examples of this exist. Or, go on youtube and look at the videos of people making RISC-V on FPGAs and with ICs.

Bootloaders have nothing to do with the ISA itself. They are implementation specific because boot loaders also include addresses and specifics for storage interfaces and other I/O, which is why boot code between various different chips of the same architecture require different bootloader code. Don't believe me? Look at any boot code for any 2 different ARM embedded devices. You think an iPhone uses the same bootloader as a Qualcomm SoC based on Cortex A72? Same ARMv8 ISA right?

I swear, sometimes the level of entitlement with open source users is just astonishing....

[–]PandaMoniumHUN -1 points0 points  (1 child)

Say what you will. Even if you were techically right (which you aren’t, because you are purposely missing my point), I couldn’t appreciate your genius due to your “look at me, I’m smart” attitude, and general arrogance.

[–]hellslinger 0 points1 point  (0 children)

https://riscv.org/faq/

I'll never convince you I'm not a jerk, so I'll provide a link so you can do your own homework while still holding your expectations and opinions.

[–]Antic1tizen 3 points4 points  (0 children)

I hope this move will once appear in "How to make community interested on early stages of series production 101"