[Diy_efi] new EFI controller

Henning Baldersheim balder at captech.no
Tue Mar 11 08:42:45 GMT 2003


At 23:30 3/10/2003 -0800, you wrote:
> > I considered linux too. That was my first choice. I chose ecos, beacuse it
> > is much more scalable and has real real-time abilities.
> > Linux also wants a mmu that the mpc555/565 lack.
> > It would not scale down as well.
> > And there where no port in progress or planned anywhere.
> > The inquires I made all pointed either to ecos or rtems.
>
>There is a realtime port of Linux called RT-Linux.  It is basically a 
>microkernel
>setup where Linux runs as a subprocess of the RT scheduler.

Yes, there are several linux RT extensions out there. Hopefully the best 
features of these will make it into the official kernel. I know the later 
2.5 version have some built in already.


>Linux also supports MMUless processors.  The reason why I felt it was viable
>is because there is a port to the Dragonball processor, which does not have
>an MMU.  If you can run Linux on a lowend Palm, you could run it on a Coldfire
>or 565.  The 565 is derived from the same family as the processors that Kodak
>uses for their cameras.  They are 66Mhz PPC derived units.  MAME runs on
>these, so I'm sure Linux isn't a huge amount of work.

The only linux version that support mmu less cpus are uClinux. (At the time 
I checked it out)
I do not know the minimum requirements for flash or ram. But a minimum of 1 
MG flash and 2-4mb ram is in the area.
Most of the SW for linux is written without considering mmu less systems. 
Especially stack usage can be a little to much. So you have to be careful.

But if real-time linux converges and becomes scalable enough it is a good 
candidate. But till then I use ecos and write posix compliant code. Then it 
can be easily moved.

>I'm considering ARM or MPC565 based products in the future, assuming that I
>can get the company rolling, since I have a day job which consumes my time.
>
> >
> > ECOS comes with flash support, clock and support for both serial ports. It
> > was not to hard to port it to the phytec board, as it had already been put
> > onto a couple of other boards.
>
>Yeah, Linux has a bazillion different drivers, they have a complete subtree
>for MTD (Memory Technology Devices) and support all varieties of flash.
>
>--Perry
>
>--
>Perry Harrington                        Data Acquisition & 
>Instrumentation, Inc
>perry at dainst dot com                                 http://www.dainst.com/
>
>Those who would give up essential liberty to purchase a little temporary 
>safety
>deserve neither liberty or safety. Nor, are they likely to end up with either.
>                              -- Benjamin Franklin
>
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