Grant Likely wrote:
On Mon, Feb 22, 2010 at 9:13 AM, Yoder Stuart-B08248
We had a similar problem in the Freescale Embedded Hypervisor
to control the generation of guest device trees. We defined
several 'magic' properties that had special meaning in
the context of a node update.
heh, so the functionality is definitely needed, but boy is that ugly!
:-)
And we haven't even mentioned node-update-phandle yet. :-)
I really do think there needs to be a syntactically distinct
method of deleting nodes and properties. Magic property names that
look like normal properties worry me.
The problem in our case is that the updates have to be done at runtime
(modifications contained in a config tree are applied to a hardware
devtree node (or hv-generated node) to produce a guest devtree node), so
to use something that doesn't look like a normal property would require
dtb format changes.
The whole node-update subtree in such a case could be considered magic.
The problem domain of this thread has no such requirement, of course.
What about something like this: Right now nodes are defined by <name>
{ [<property>|<node>]; ... }; and properties are defined by <name>; or
<name> = <value>; To differentiate a command from either a node or
property definition, perhaps round braces could be used:
so for the definition:
a-node {
property-1;
property-2 = "blah";
child-1 {
...
};
};
you could delete property-2 and node-1 with:
a-node {
delete-node(child-1);
delete-property(property-2);
};
We also had the need to prepend to a <stringlist> so that
compatible properties could be updated.
prepend-stringlist <stringlist> The value is a string list that
specifies on or more property name/value
pairs.
This is a bit of a harder problem. I've go no ideas on how to handle
this in a syntactically elegant way.
As long as we're talking about dts-level static manipulation (i.e. not
magic properties), we're not limited to one instance of each command
name, so we could just do:
prepend-stringlist("compatible", "foo,bar");
prepend-stringlist("compatible", "foo,bar-X.Y");
prepend-stringlist("something-else", "aoeuhtns");
We need the quotes around node/property names since comma is a legal
character in them.
-Scott
_______________________________________________
devicetree-discuss mailing list
[email protected]
https://lists.ozlabs.org/listinfo/devicetree-discuss
