On Sun, 2015-06-07 at 08:54 +0100, Grant Likely wrote: > > IE. conceptually, what overlays do today is quite rooted around the idea > > of having a fixed "base" DT and some pre-compiled DTB overlays that > > get added/removed. The design completely ignore the idea of a FW that > > maintains a "live" tree which we want to keep in sync, which is what we > > want to do here, or what we could do with a "live" open firmware > > implementation. > > Right, which is exactly the reason for the changeset/overlay split. > Overlays assume a fixed base, and that overlays are kind of like plug-in > modules. changeset makes no such assumption. So you suggest we create a function that takes an fdt and an "anchor" as input, and expands that FDT below that anchor, but does so by using the changeset API under the hood ? Even that looks somewhat tricky (turn that bit of FDT into a pile of changeset actions), however, I can see how we could create a new function inside changeset to attach a subtree. Ie. of_attach_subtree() (which could have it's own reconfig action but we don't care that much yet), which takes an expanded subtree and an anchor, and calls of_attach_node() in effect for all nodes in there. We could then have a two pass mechanism in our hotplug code: - Expand the bit of fdt into a separate tree - Use of_attach_subtree to "add" that subtree to the main tree What do you think ? Ben. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
