[PATCH] Support multiple MEM tags with atags->fdt conversion

Nicolas Pitre nicolas.pitre at linaro.org
Thu Jun 16 06:20:15 EST 2011


On Wed, 15 Jun 2011, David Brown wrote:

> On Wed, Jun 15 2011, Nicolas Pitre wrote:
> 
> > On Tue, 14 Jun 2011, David Brown wrote:
> >
> >> Some targets have multiple memory regions.  Parse up to 8 of these
> >> when converting the atags to fdt.
> >> 
> >> Signed-off-by: David Brown <davidb at codeaurora.org>
> >
> > I've added your patch to my zImage patch queue.
> >
> >> With this change, I am able to boot MSM8x60 combining ATAGS and my DT.
> >> It seems to work as long as my device tree has placeholders for all of
> >> the properties I need.
> >
> > I think those missing nodes should simply be created if missing.  I 
> > however don't see any function in the libfdt API to do that -- there is 
> > fdt_add_subnode() but no fdt_add_node().  Any DT expert please?
> 
> It does seem to only work if I already have nodes that are large enough
> to hold the properties coming from the ATAG.  For example, I have to
> have an array of memory reg values large enough, as well as a command
> line large enough to hold the one passed from the bootloader.
> 
> If the DTB's command line is smaller than the one from ATAG, it just
> silently leaves the DTB one in place.

That I can explain, and that looks easy to fix.


Nicolas


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