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

Rob Herring robherring2 at gmail.com
Thu May 14 10:18:37 AEST 2015

On Wed, May 13, 2015 at 6:35 PM, Benjamin Herrenschmidt
<benh at kernel.crashing.org> wrote:
> On Tue, 2015-05-05 at 07:14 +1000, Benjamin Herrenschmidt wrote:
>> So the "trivial" way to do it (and the way we have implemented the FW
>> side so far) is to have the FW simply "flatten" the subtree below the
>> slot and pass it to Linux, with the intent of expanding it back below
>> the slot node.
>> This is what Gavin proposed patches do.
>> The overlay mechanism adds all sorts of features that we don't seen to
>> need and would make the above more complex.
> Guys, I never got a final answer from you on this. Are we ok with adding
> the way to just expand a subtree or are you insistent we need to use the
> overlap mechanism ?

I haven't decided really.

The main thing with the current patch is I don't really like the added
complexity to unflatten_dt_node. It is already a fairly complex
function. Perhaps removing of "hybrid" as discussed will help?

If there are things we can do to make overlays easier to use in your
use case, I'd like to hear ideas. I don't really buy that being more
complex than needed is an obstacle. That is very often the case to
have common, scale-able solutions. I want to see a simple case be
simple to support.


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