Recommended soft CPU for FPGA for Linux-mips?

Recommended soft CPU for FPGA for Linux-mips?

[Timothy J Massey]

Hello

I’m trying to find a recommendation for a soft CPU to run Linux-mips.
Ideally, I have a Terasic De0-nano board and I would like to use it to
synthesize a MIPS CPU I could use to boot a mainline MIPS kernel with.  I
originally purchased this to use with OpenRISC, but that seems to have
stalled: I’d rather work with something more mainstream if I can.  MIPS
seemed like a great intersection of simplicity and real-world practicality.
If another (affordable) board would be a better fit, I’m certainly open.
But I would like to use a fully synthesized open CPU if at all possible.

I’ve tried Googling for recommendations, but this is made difficult by a
few things:  proprietary soft cores provided by FPGA makers and tied to
their FPGA’s; “MIPS-like” cores that are vague about what “MIPS-like”
really means; and the confusion around the presence or absence of unaligned
load/store and what impact that has.  (My understanding is the patents have
expired, so it shouldn’t be necessary to avoid them anymore?).

MIPS Open hasn’t made this any easier.  They trumpet their openness, but
wrap everything up into a confusing mess of “products” that are more sales
information than anything else.

And while the Linux-MIPS website lists compatible computers, SoC, etc., I
didn’t see any listings for any FPGA / soft CPU environments.

Do you have any suggestions for a recommended soft CPU to use with
Linux-mips?  Any information would be appreciated.

Thank you!

Timothy Massey

回复:Recommended soft CPU for FPGA for Linux-mips?

[Jiaxun Yang]

 ---- 在 星期五, 2020-03-13 09:00:12 Timothy J Massey <tmassey@modernmerchant.com> 撰写 ----
 > 
 > Hello
 > 
 > I’m trying to find a recommendation for a soft CPU to run Linux-mips.
 > Ideally, I have a Terasic De0-nano board and I would like to use it to
 > synthesize a MIPS CPU I could use to boot a mainline MIPS kernel with.  I
 > originally purchased this to use with OpenRISC, but that seems to have
 > stalled: I’d rather work with something more mainstream if I can.  MIPS
 > seemed like a great intersection of simplicity and real-world practicality.
 > If another (affordable) board would be a better fit, I’m certainly open.
 > But I would like to use a fully synthesized open CPU if at all possible.
 > 
 > I’ve tried Googling for recommendations, but this is made difficult by a
 > few things:  proprietary soft cores provided by FPGA makers and tied to
 > their FPGA’s; “MIPS-like” cores that are vague about what “MIPS-like”
 > really means; and the confusion around the presence or absence of unaligned
 > load/store and what impact that has.  (My understanding is the patents have
 > expired, so it shouldn’t be necessary to avoid them anymore?).
 > 
 > MIPS Open hasn’t made this any easier.  They trumpet their openness, but
 > wrap everything up into a confusing mess of “products” that are more sales
 > information than anything else.
 > 
 > And while the Linux-MIPS website lists compatible computers, SoC, etc., I
 > didn’t see any listings for any FPGA / soft CPU environments.

mipsfpga-soc from wavecomp is supported but it's only for university
teaching purpose and I'm not sure if you can still apply for it.
 
> 
 > Do you have any suggestions for a recommended soft CPU to use with
 > Linux-mips?  Any information would be appreciated.
 > 
 > Thank you!
 > 
 > Timothy Massey

Thanks.


--
Jiaxun Yang