[U-Boot-Users] uboot clock configuration on mpc5200 boards

Jon Smirl
2007-11-21T02:37:42Z

On 11/20/07, Grant Likely <grant.likely@secretlab.ca> wrote:
> On 11/20/07, Jon Smirl <jonsmirl@gmail.com> wrote:
> > On the Linux kernel the mpc52xx_setup_cpu() function used to do this
> > fix up. Does uboot handle this for mpc5200 boards? If so, which
> > version?
> >
> > uboot is accessing these registers but it is not clear to me if the
> > clocks are completely being set up.
> >
> > The 5200lite code has been changed to this:
> >
> > /*
> > * Fix clock configuration.
> > *
> > * Firmware is supposed to be responsible for this. If you are creating a
> > * new board port, do *NOT* duplicate this code. Fix your boot firmware
> > * to set it correctly in the first place
> > */
> > static void __init
> > lite5200_fix_clock_config(void)
> > {
> ----8<----snip---->8----
> > }
> >
> > Is uboot setting this up correct now that they kernel has been changed?
> >
>
> Strictly speaking; firmware should be responsible for configuring the
> SoC (clocks, pinouts, etc). It makes it easier to add new boards if
> each one doesn't need it's own fixups.
>
> I haven't checked the clock setup for lite5200 in u-boot yet, but it
> is not a complex change. And even if I do change it for the lite5200
> in u-boot; this code probably won't go away in the kernel so as not to
> break compatibility with lite5200's with older u-boot firmware.

Let me know when you sort it out in uboot. I'm using a Phytec pc030
and they've copied all of the 5200lite code. We're also building our
own hardware which isn't ready yet.

>
> The point is that firmware should setup the CPU correctly at boot. It
> should not be Linux's responsibility. However, if there is *existing*
> firmware that needs to be supported; then I'll grudgingly accept hacks
> like this to keep the board bootable. If it is a new board, do it
> right the first time and do it in firmware (be it u-boot or otherwise)
>
> Cheers,
> g.
>
> --
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.
> grant.likely at secretlab.ca
> (403) 399-0195
>

--
Jon Smirl
jonsmirl at gmail.com