Hi Frank, frowand.list@xxxxxxxxx writes: > From: Frank Rowand <frank.rowand@xxxxxxxx> > > Remove "phandle", "linux,phandle", and "ibm,phandle" properties from > the internal device tree. The phandle will still be in the struct > device_node phandle field and will still be displayed as if it is > a property in /proc/device_tree. > > This is to resolve the issue found by Stephen Boyd [1] when he changed > the type of struct property.value from void * to const void *. As > a result of the type change, the overlay code had compile errors > where the resolver updates phandle values. > > [1] http://lkml.iu.edu/hypermail/linux/kernel/1702.1/04160.html > > - Add sysfs infrastructure to report np->phandle, as if it was a property. > - Do not create "phandle" "ibm,phandle", and "linux,phandle" properties > in the expanded device tree. > - Remove phandle properties in of_attach_node(), for nodes dynamically > attached to the live tree. Add the phandle sysfs entry for these nodes. > - When creating an overlay changeset, duplicate the node phandle in > __of_node_dup(). > - Remove no longer needed checks to exclude "phandle" and "linux,phandle" > properties in several locations. > - A side effect of these changes is that the obsolete "linux,phandle" and > "ibm,phandle" properties will no longer appear in /proc/device-tree (they > will appear as "phandle"). Sorry but I don't think that can work for us. Our DLPAR (ie. CPU/memory/device hotplug) stuff on PowerVM uses "ibm,phandle", and it's not the same thing as "phandle" / "linux,phandle". I don't know the code well myself, but the spec (PAPR) says: Note: If the “ibm,phandle” property exists, there are two “phandle” namespaces which must be kept separate. One is that actually used by the OF client interface, the other is properties in the device tree making reference to device tree nodes. These requirements are written to maintain backward compatibility with older FW versions predating these requirements; if the “ibm,phandle” property is not present, the OS may assume that any device tree properties which refer to this node will have a phandle value matching that returned by client interface services. I have systems here that still use "ibm,phandle". I also see at least some of the userspace code that looks for "ibm,phandle", and nothing else. The note above actually implies that the current Linux code is wrong, when it uses "ibm,phandle" as the value of np->phandle. So sorry that's a big mess, but we can't just rip out those properties. I think the minimal change would be to treat "ibm,phandle" like a normal property, I think that would allow our tools to keep working? The other thing that worries me is that by renaming (effectively) "linux,phandle" to "phandle", we lose the ability to accurately regenerate the device tree from /proc/device-tree. In theory it shouldn't matter, but I worry that in practice something will break. What if we just kept a single bit flag somewhere indicating if the name of the phandle property we found was "phandle" or "linux,phandle", and create the sysfs phandle using that name? cheers -- 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
