Re: Linux on Cirrus EP93xx

[Claudio Scordino <cloud.of.andor@xxxxxxxxx>]

Lennert Buytenhek wrote:
> On Tue, Apr 03, 2007 at 11:52:44AM +0200, Claudio Scordino wrote:
>
> > - Cirrus distributes a patched 2.6.8.1 kernel for such cpu. At the
> > same time, also the standard 2.6.20 kernel supports the cpu.  Which
> > kernel is better ? What kind of support each kernel misses ?
>
> The advantage that 2.6.8.1-cirrus currently still has is more complete
> peripheral support.  The advantage of 2.6.20 is that you get all the
> bug fixes and improvements that have happened in Linux between 2.6.8.1
> and 2.6.20.
>
> If you use 2.6.20, you'll likely to get support for it on these mailing
> lists, whereas if you use 2.6.8.1-cirrus, you probably won't.
>
> If you use 2.6.8.1-cirrus, on the other hand, you get the guarantee that
> all ep93xx code was 100% written by Cirrus employees[*] -- whether that
> is something that gives you a warm fuzzy feeling inside is left up to you.

Thank you for the explanations. I read the emails and I saw that Cirrus is going 
on its way with its (pretty old) kernel. I'm sure that soon the mainline kernel 
will have all the features of Cirrus's plus many more features :)


> > - My application has many floating point operations, so I want to
> > exploit the Maverick Crunch Math engine of the cpu. What kind of
> > toolchain do I need to enable such engine ? Does a standard
> > no-soft-float toolchain work ?
>
> A hardfloat toolchain?  Probably not, unless you want to write all your
> floating point code in assembly.  Try either a softfloat or EABI toolchain
> and userland.

Yes, I need a hardfloat toolchain for that processor. Since Cirrus claims that 
the Maverick Crunch works with "predefined coprocessor instructions by utilizing 
standard ARM compiler tools" I assumed that a standard toolchain could work with 
their processor.

Does Cirrus provide any hardfloat toolchain for the Maverich ?

I've seen that in the download area, Cirrus provides 3 toolchains:

arm-elf-gcc-3.2.1-full.tar.bz2
arm-linux-gcc-3.3-full.tar.bz2
arm-linux-gcc-3.4.3-1.0.1.tar.bz2

but I didn't unserstand the differences among such toolchains...

Many thanks for your help,

           Claudio

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