*SPAM* [uClinux-dev] uClinux port to Lattice's Mico32

[Michael Schnell]

> Yep, Mico32 is a quite simple soft-core based upon RISC architecture.
> For the most part of it it resembles both NiosII and, using a lot of
> fantasy, MIPS (it has a lot of registers, compared to ARM). Of course,
> it currently lacks MMU support. 

My impression is that it could be viable to create a common "arch" for 
several similar ip-core processors (namely NIOS II, MicroBlaze and 
Micro32), in a way that the sub-archs are different only in some 
preprocessor variables. By this, there would be much more impact to the 
effort to bring these processors into the main µCLinux tree.

> - no support for atomic operation used in semaphore handling
>   
I suppose the same is true for NIOS.
How is this handled ? Is multiprocessor possible/planned with your port 
? I do know that the Altera SDK comes with HDL code for a hardware 
semaphore, so that could be usable with multiple processors. It should 
be quite easy to create a custom instruction from the semaphore HDL 
code, instead of using it as a kind of I/O port, if that seems to be viable.
> In my opinion
> ARM has a strong support for multi-processor, multi-platform
> configuration and since a soft-core can be potentially used on a wide
> variety of appliance, it seems to me that starting from ARM was the
> right choice.
>   
While I cant comment on your conclusion, I feel that multiprocessor 
support is really critical with a port for the said processors, as it's 
easily possible to configure an FPGA to contain lots of CPU cores.
> Any comments about the way to distribute the patch, since it's still
> in a very early stage? Perhaps someone wants to join the journey...
>   
In this list there are a number of mails regarding upgrading NIOS to the 
latest µCLinux version. Moreover in the NIOS µCLinux forum another team 
is doing the same. My friend Ben from S/H (Altera distribution) is 
interested in that, too. I am interested, as well, of course, but 
(despite of a background of 25 years of embedded programming) I'm quite 
a newbie as well with NIOS as with Linux.

-Michael