SpinalHDL VS litedram

I'd love to see textual preprocessors kinda banned. Or at least done upstream and outside of the language. You can't both be and also have a textual preprocessor defined internally. It doesn't work.

I really like what Zig and C++ are doing with `const`.

https://ikrima.dev/dev-notes/zig/zig-metaprogramming/

Have you looked at Spinal?

https://github.com/SpinalHDL/SpinalHDL

https://spinalhdl.github.io/SpinalDoc-RTD/master/index.html

Many companies do just write entire modern SoCs in straight Verilog (maybe with some autogenerated Verilog hacked in there) with no other major organization tools aside from the typical project management stuff. The load-store unit of a modern CPU alone easily exceeds 10k lines of Verilog. It's a similar thing as people who work with kernels—after all, the page table management code in a modern operating system like Linux is absolutely monstrous but still people are able to understand it well enough to be able to make the changes they need and get out.

If you are interested in other languages which hope to make this sort of stuff easier, I'd recommend taking a look at design productivity languages like Chisel and it's associated Chipyard [1], SpinalHDL [2], and Bluespec [3]. Each of these are meant to make defining extremely complex hardware more manageable for humans and there's a lot of interesting work going on right now with each of them.

[1] https://github.com/ucb-bar/chipyard

[2] https://github.com/SpinalHDL/SpinalHDL

[3] https://github.com/B-Lang-org/bsc

I have just found that SpinalHDL also implemented two halves of the fully registered buffer in Stream.scala.

Don’t forget SpinalHDL that was forked off of Chisel 2 I believe. These DSLs really leveraged the software features of Scala to help build generalised/modular systems. And are generally a quality of life improvement in the language features available.

A lot of reuse from other FOSH projects, including Litex, SpinalHDL, betrusted & u/alexforencich verilog-wishbone. Thanks to all of them :-)

You could try to implement a PCIe root complex for FOSS SoCs, connecting to e.g. Wishbone as the main bus. There's already some DDR3 controller (or this one) and USB Host controller out there, and even device-side PCIe, but no FOSS host-side PCIe that I know of. Probably quite a difficult job though, even sticking to the lower-speed PCIe 1.

I could be wrong, but I don't think the LiteX DRAM PHY is using the UG586 block. Here's the Litex Series 7 DRAM PHY source code - it appears to be hardcoding the PHY logic. The Lattice ECP5 code in that directory does the same thing.

Try https://github.com/enjoy-digital/litedram with a RAW or FIFO interface. It is in Migen, a python DSL HDL, but you could just use the output.

You could try to implement a PCIe root complex for FOSS SoCs, connecting to e.g. Wishbone as the main bus. There's already some DDR3 controller (or this one) and USB Host controller out there, and even device-side PCIe, but no FOSS host-side PCIe that I know of. Probably quite a difficult job though, even sticking to the lower-speed PCIe 1.

So for instance (and AFAI understand...) the DDR2 sdram controller uses a generic PHY (https://github.com/enjoy-digital/litedram/blob/master/litedram/phy/gensdrphy.py) , but the DDR3 one has to talk to some vendor-specific PHY (e.g. https://github.com/enjoy-digital/litedram/blob/master/litedram/phy/s7ddrphy.py ). The controller itself is vendor-agnostic (https://github.com/enjoy-digital/litedram/blob/master/litedram/core/controller.py). On Xilinx FPGA it doesn't rely on MIG at all.