Re: Handling of modular boards

[Ben Dooks <ben@trinity.fluff.org>]

On Fri, May 04, 2012 at 01:50:01PM -0600, Stephen Warren wrote:
> On 05/04/2012 12:58 PM, Mark Brown wrote:
> > Quite a few reference platforms (including Wolfson ones, which is why
> > I'm particularly interested) use replaceable modules to allow
> > configuration changes.  Since we can often identify the configuration at
> > runtime we should ideally do that but currently there's no infrastructure 
> > to help with that...
> 
> So, I'll respond within the context of device tree, although perhaps you
> were looking for something more general?
> 
> I was just asked basically the same question internally to NVIDIA. One
> option that was floated was to store the device tree in chunks and have
> the bootloader piece them together. You'd start with the DT for the
> basic CPU board, probe what HW was available, and then graft in the
> content of additional DT chunks and pass the final result to the kernel.
> The advantages here are:
> 
> a) The DT is stored in chunks for each plugin board, so there's no bloat
> in the DT that gets passed to the kernel; it contains exactly what's on
> the board.

Interesting, but how does it sort ofu things like mapping GPIO lines from
the add-in board's view to the rest of the system?


-- 
Ben Dooks, ben@fluff.org, http://www.fluff.org/ben/

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