Re: Deprecating reserve-map in favor of properties

On Fri, 02 Nov 2012 06:41:36 +1100, Benjamin Herrenschmidt [off-list ref] wrote:

On Thu, 2012-11-01 at 15:21 +0100, Grant Likely wrote:

quoted

I think this makes sense. Cyril and I are just talking about what he
needs. He wants to set aside per-device reserved regions and would
like to have the ability to reference a particular reserved region
from a device node, probably with a phandle. I like the look of the
reserved-{ranges,names} properties in the root, but I see the argument
that it isn't very flexible. What about something like this:

reserved-memory {
        reserved@0x10000000 { reg = <0x10000000 0x08000000>; };
        reserved@0x01000000 { reg = <0x01000000 0x00200000>; };
}

The node name of the child nodes could be different of course.

I'm not that fan of different nodes, especially nodes with nodes in them
for that purpose. Seems overkill.

Can't he reference reserved entries as <phandle>,<index> pairs ?

That would work too.

I still think a single property would do fine. We could mandate those be
in the respective "memory" nodes but them you have potentially to break
up reserved regions if you have multiple memory nodes (NUMA) etc...

It makes sense to me for the reserved ranges to be kept with the memory
nodes themselves, even if it does mean that sometimes they need to be
split up for multiple memory nodes.

quoted

Right, that would work also even though I prefer phandle references in
general. Is it conceivable that additional data would want to be
attached to a particular reserved region?

phandle references and names aren't exclusive from each other. The name
remains a useful diagnostic tool.

If you want additional data, make a node somewhere to represent that
region along with its additional data, that node can have a reference to
the reserved map entry.

I'd keep the reserve map itself simple. It's a "synthetic property" a
bit like the memory nodes. IE. The "memory" nodes don't have to
represent physical memory controllers & DIMMs. They represent the
overall view of memory by the CPUs. You can represent the MCs and the
DIMMs elsewhere in the SoC node.

okay.

g.