[rfc] mips74k/ar9344 support

[Warner Losh]

More comments:

For COP0_HAZARD, I'd add a pointer to See Mips Run, 2nd Ed in a comment on explaining why.

You're also still using .word 0xc0 in cpuregs.h.

Warner

On Sep 29, 2013, at 4:50 PM, Adrian Chadd wrote:

> Hi,
> 
> Right:
> 
> http://people.freebsd.org/~adrian/mips/20130929-mips74k-3.diff
> 
> 
> 
> -adrian
> 
> 
> 
> On 29 September 2013 07:43, Warner Losh <imp at bsdimp.com> wrote:
> I'd be tempted to use 'sll zero, 3' instead of '.word 0xc0' and define a macro for it. Why 'sll zero,3' instead of ehb? It allows us to use it on older MIPS platforms as well... (because it will assemble in other modes, not for binutils issues)...
> 
> Speaking of which, I'd also change the last 'nop' on the HAZARD_DELAY and ITLBNOPFIX to be 'sll zero, 3' as well. This will be an appropriate nop on older kit, as well as 'fail safe' when someone starts to cope with newer compilers.  Ditto COP0_SYNC.
> 
> On Sep 29, 2013, at 4:37 PM, Adrian Chadd wrote:
> 
> > grr, wrong list.
> >
> > also, try this:
> >
> > http://people.freebsd.org/~adrian/mips/20130929-mips74k-2.diff<http://people.freebsd.org/~adrian/mips/20130929-mips74k-1.diff>
> >
> >
> >
> > -adrian
> >
> > ---------- Forwarded message ----------
> > From: Adrian Chadd <adrian at freebsd.org>
> > Date: 29 September 2013 04:38
> > Subject: [rfc] mips74k/ar9344 support
> > To: "freebsd-wireless at freebsd.org" <freebsd-wireless at freebsd.org>
> >
> >
> > Hi!
> >
> > Here's an initial hacked up patch to get the AR9344 to mountroot> .
> >
> > (Which isn't true - it panics due to missing PHY setup on if_arge; I'll fix
> > that up soon.)
> >
> > http://people.freebsd.org/~adrian/mips/20130929-mips74k-1.diff
> >
> > The specific changes:
> >
> > * add CPU_MIPS24KC and CPU_MIPS74KC
> > * mips32r2 CPUs require an EHB as a hazard for things, rather than NOPs
> > * mips74k cores have a different CCA (cache coherency attributes) than the
> > default - I lifted this from the netbsd mips support.
> >
> > now, the ar71xx CPUs are all currently marked as CPU_MIPS4KC. I'll follow
> > this up with a commit to change that. There may be things we can optimise
> > in the CPU_MIPS24KC case.
> >
> > Warner and I have started talking about how to properly fix all of the
> > hazard handling. We'll discuss that later.
> >
> > I'd like to commit this to -HEAD so people wishing to hack on mips74k
> > platforms can do stuff. Does anyone have any issues with the above?
> >
> > Thanks,
> >
> >
> >
> > -adrian
> > _______________________________________________
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> 
>