From: Juergen Beisert <jbe@pengutronix•de>
To: benh@kernel•crashing.org
Cc: linuxppc-dev@ozlabs•org
Subject: Re: MPC5200 PCI interrupt routing
Date: Thu, 25 Sep 2008 09:51:14 +0200 [thread overview]
Message-ID: <200809250951.15941.jbe@pengutronix.de> (raw)
In-Reply-To: <1222291345.8277.92.camel@pasglop>
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=20
external clock or usage of the internal clock generator (=3D how to setup t=
he=20
frequency divider)?
> > However, if firmware *cannot* be changed, there is a workaround.
> > You can create a new platform specific board support file in
> > arch/powerpc/platforms/52xx/ that matches against your specific board
> > and performs the needed fixups. An example of this is lite5200.c. Many
> > lite5200 boards have older versions of U-Boot installed which does not
> > correctly configure clocks or port-config. So, lite5200.c matches to
> > the board instead of mpc5200_simple.c so that the board specific fixups
> > can be performed easily. You should do the same for your board.
>
> I tend to thing that drivers should deal with their own clocks.
ACK. But only to switch them on and off. Not to configure them.
> In fact it would be nice if one could stop the clocks while the host port=
is
> in suspend no ?
ACK.
Juergen
=2D-=20
Dipl.-Ing. Juergen Beisert | http://www.pengutronix.de
=A0Pengutronix - Linux Solutions for Science and Industry
=A0 Handelsregister: Amtsgericht Hildesheim, HRA 2686
=A0 =A0 =A0 Vertretung Sued/Muenchen, Germany
Phone: +49-8766-939 228 | Fax: +49-5121-206917-9
next prev parent reply other threads:[~2008-09-25 7:51 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-22 13:56 MPC5200 PCI interrupt routing Juergen Beisert
2008-09-22 15:12 ` Juergen Beisert
2008-09-22 21:01 ` Matt Sealey
2008-09-23 11:34 ` Juergen Beisert
2008-09-24 15:16 ` Juergen Beisert
2008-09-24 18:15 ` Grant Likely
2008-09-24 21:22 ` Benjamin Herrenschmidt
2008-09-24 21:34 ` Jon Smirl
2008-09-25 7:51 ` Juergen Beisert [this message]
2008-09-25 8:34 ` Benjamin Herrenschmidt
2008-09-25 16:57 ` Grant Likely
2008-09-25 18:02 ` Jon Smirl
2008-09-25 18:12 ` Grant Likely
2008-09-25 16:54 ` Grant Likely
2008-09-25 21:41 ` Benjamin Herrenschmidt
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