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To: linuxppc-dev@ozlabs.org
Subject: I don't understand #size-cells = <0>
Date: Wed, 31 Jan 2007 16:22:12 -0800
From: Andrew Klossner <andrew@cesa.opbu.xerox.com>
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I'm porting the kernel to an 8548-based board whose boot loader does
not provide a device tree, so I'm rolling my own.

Rev 0.5 of booting-without-of.txt says:

	"reg" properties are always a tuple of the type "address size"
	where the number of cells of address and size is specified by
	the bus #address-cells and #size-cells.

but in the examples, we see

		reg = <22000 1000>;
		#address-cells = <1>;
		#size-cells = <0>;

The number of cells of address is 1.  The number of cells of size is 0.
1+0=1, so how can the reg property have a tuple of size 2?

I saw Ben's mention last June of a "degenerate range", but I can't
find that term used anywhere else.

What are the real semantics of #size-cells = <0> ?

Thanks,
Andrew Klossner