[PATCH v4 19/21] drivers/of: Support adding sub-tree

[Rob Herring]

On Fri, May 1, 2015 at 10:22 AM, Benjamin Herrenschmidt
<benh at kernel.crashing.org> wrote:
> On Fri, 2015-05-01 at 07:54 -0500, Rob Herring wrote:
>
>> The difference seems to be whether you allocate space or just point to
>> the FDT for various strings/data. Is that right?
>>
>> >    * of_fdt_add_subtree() is the introduced API to do the work.
>>
>> Have you looked at overlays and if so why do they not work for your purposes?
>>
>> Why do you need to do this with the flattened tree?
>
> The basic idea I asked Gavin to implement is that since the FW needs to
> provide a bunch of DT updates to Linux at runtime in the form of new
> nodes below an existing one, rather than doing it via some new/custom
> format, instead, have it send a bit of FDT blob to expand under an
> existing node.

Overlay = an FDT blob to graft into a live running system. Sounds like
the same thing.

> As for the details of Gavin implementation, I haven't looked at it in
> details yet so there might be issues there, however I don't know what
> you mean by "overlays", any pointer ?

CONFIG_OF_OVERLAY

http://events.linuxfoundation.org/sites/events/files/slides/dynamic-dt-keynote-v3.pdf

Rob