Re: MPC5200 PCI interrupt routing

[Grant Likely <grant.likely@secretlab.ca>]

On Thu, Sep 25, 2008 at 09:51:14AM +0200, Juergen Beisert wrote:
> Benjamin,
> 
> On Mittwoch, 24. September 2008, Benjamin Herrenschmidt wrote:
> > On Wed, 2008-09-24 at 12:15 -0600, Grant Likely wrote:
> > > On Wed, Sep 24, 2008 at 05:16:34PM +0200, Juergen Beisert wrote:
> > > > On Dienstag, 23. September 2008, Juergen Beisert wrote:
> > > > > What Kernel do you run on your target? On my hardware a 2.6.23 still
> > > > > work as expected, but a 2.6.26 fails all the time.
> > > >
> > > > One should enable the internal USB clock. If done, it works... In
> > > > 2.6.23 is was done in mpc52xx_common.c. It was removed in 2.6.24.
> > >
> > > It was removed because some 5200 platform do not use USB and should not
> > > enable the internal clock.  In general, it is not the kernel's job to
> > > configure clocking and pin usage on the chip.  Instead, it should be set
> > > correctly at power up by U-Boot.
> >
> > Or by the USB host driver :-)
> 
> But how to deal with platform specific things like (in this case) unknown 
> external clock or usage of the internal clock generator (= how to setup the 
> frequency divider)?

The external clock would need to be encoded in the device tree.

Internal clock would need to read/detect the CDM config and make a
decision based on that.  Certainly possible, but I just don't think that
it is really important.  (And even if it is, I think it should be done
in common platform setup code, not the driver, because it is very
MPC5200 SoC specific).

g.