[Power.org:parch] devicetree: Musings on reserved regions

[Scott Wood]

On Tue, 8 Feb 2011 08:39:26 +1100
Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:

> 
> > In addition to the reserved regions block in the header, define a set
> > of properties in the memory node that specify the reserved regions
> > with the name reflecting the usage.
> > For example:
> > 
> > 	memory at 0 {
> > 		device_type = "memory";
> > 		reg = <0 0x40000000>;
> > 		reserved-ramdisk = <0xc00000 0x200000>; /* 2MB ramdisk */
> > 		reserved-dtb = <0xbf0000 0x1000>; /* devicetree */
> > 		reserved-fb0 = 0x1000000 0x400000>; /* framebuffer */
> > 	};
> > 
> > Each reserved property would start with "reserved-" followed by a
> > name.  reserved-ramdisk and reserved-dtb would be reserved for ramdisk
> > and dtb images respectively.  Other names could also be defined; for
> > example, reserved-openfirmware.
> 
> I very much dislike the list of properties with magic names. I'd rather
> have a pair of properties containing lists (reserved-names and
> reserved-ranges).

How about a node:

memory at 0 {
	device_type = "memory";
	reg = <0 0x40000000>;

	reserved {
		ramdisk = <0xc00000 0x200000>; /* 2MB ramdisk */
		dtb = <0xbf0000 0x1000>; /* devicetree */
		fb0 = <0x1000000 0x400000>; /* framebuffer */
		something-fragmented = <0x800000 0x100000 0xa00000 0x100000>;
	};
};

Or is the objection to any use of the property name to indicate reservation type,
rather than the magic "reserved-" prefix?

-Scott