gateworks/avila board support

[M. Warner Losh]

In message: <20080326135631.GA71377 at zibbi.meraka.csir.co.za>
            John Hay <jhay at meraka.org.za> writes:
: On Fri, Mar 21, 2008 at 01:59:26PM -0700, Sam Leffler wrote:
: > I'm working to fill in the missing bits for gateworks/avila boards.  I 
: > just fixed usb and am working on the 4-port switch, ixp425 crypto 
: > support, and anything else I hit.  I'm aware of one issue where stuffing 
: > all 4 mini-pci slots in a 2348-4 board results in unreliable interrupts.
: > 
: > If you are aware of any other problems please let me know or better yet 
: > file a PR and assign it to me.  Can't promise I can fix 'em this time 
: > 'round but will try.
: 
: One thing that is not really a problem that I have been thinking about,
: but do not have an answer for yet.
: 
: We have the current Avila ixp425 based port and then there is the
: Pronghorn Metro from ADI that I am busy with and then the new gateworks
: boards that you are busy with. It seems that they should all be able to
: use a single kernel except for the hints file. So what I have been
: wondering about is if it might be possible to have multiple hints files
: compiled in with a mechanism to select the correct one. Or maybe teach
: my redboot based boot loader to select the correct hint file.
: 
: I'm still trying to get my head around how the i386 loader load the
: device.hints file though. :-)

There's a standard in the linux world for passing the board ID from
the boot loader to the kernel.  I had hoped to use that for a board
based initialization routine.  Sometimes hints are all that's needed
for the per-board support, but other times code needs to execute to
turn on clocks and the like.  We should move more towards this model.
To effectively support it, one would need to be able to augment hints
at run time.  This is needed both for flavoring an individual board,
as well as for supporting multiple different SoCs with one kernel.

Augmenting hints at run time would be easy, but there's no support for
doing this now.  I looked at adding it at one point, but have always
been too busy to find the time..

Warner