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Subject: RE: [PATCH v2] Device tree bindings for Xilinx devices
Date: Tue, 16 Oct 2007 11:24:07 -0700
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From: "Stephen Neuendorffer" <stephen.neuendorffer@xilinx.com>
To: "Grant Likely" <grant.likely@secretlab.ca>, <linuxppc-dev@ozlabs.org>,
	"Wolfgang Reissnegger" <wre@xilinx.com>, "Leonid" <Leonid@a-k-a.net>,
	<microblaze-uclinux@itee.uq.edu.au>
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> +   n) Xilinx EMAC and Xilinx TEMAC
> +
> +   Xilinx Ethernet devices.  Uses common properties from=20
> other Ethernet
> +   devices with the following constraints:
> +  =20
> +   Required properties:
> +    - compatible : Must include one of: "xilinx,plb-temac",
> +                   "xilinx,plb-emac", "xilinx-opb-emac"
> +    - dma-mode : Must be one of "none", "simple", "sg" (sg=20
> =3D=3D scatter gather)

I think it's going to be a significant headache to remap things like the
dma-mode from the xilinx configurations to something else, and then
interpret them correctly in the drivers.

Although it lacks a bit in style, perhaps, I'd greatly prefer having
something like:

	Ethernet_MAC {
		xilinx,C_DMA_PRESENT =3D <1>;
            ...
      }

(which happens to correspond to "none" above)
DMA mode is perhaps a bad example, since the Xilinx EDK encoding for
this is so unnecessarily obfuscated, but I'd like to avoid setting
precedent for defining a new set of parameterizations here.  In the long
term, I'm afraid this will just be an added source of confusion and more
code to maintain.

Steve