Re: [PATCH 20/20] bootwrapper: Add fsl_get_immr(), mpc885_get_clock(), and pq2_get_clocks().

On Tue, Aug 21, 2007 at 11:34:45AM -0500, Scott Wood wrote:

David Gibson wrote:

quoted

On Mon, Aug 20, 2007 at 12:40:13PM -0500, Scott Wood wrote:

quoted

fsl_get_immr() is equivalent to the kernel's get_immrbase() function.

I notice that this function assumes that P==V.  Is that true for all
relevant platforms at this point?

Yes.  If that ever changes, we'd probably need to add a virtual-immr or 
similar.

Ok.

quoted

quoted

mpc885_get_clock() transforms a crystal frequency into a system frequency
according to the PLL register settings.

pq2_get_clocks() does the same as the above for the PowerQUICC II,
except that it produces several different clocks.

I'd prefer if these functions worked analagously to the
ibm440gp_fixup_clocks() function in ebony.c and fixed up the clock
values in the device tree directly, rather than returning them (where
the caller will presumably poke them into the device tree).

I wanted to separate the register interpretation from the knowledge of 
where things are in the device tree.

Hrm.  I considered that for a while with 44x, before deciding it
wasn't worth the extra hassle of passing a bunch of things around.  If
you look at the 44x version, you'll see that the device tree poking
part is just the last few lines of the function and more-or-less
independent from the rest of it.  So it should be easy to make the
function separable into hw-logic vs. dt-logic portions if we ever need
to.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson