Hi,
On Tue, Jun 27, 2017 at 08:28:49PM +1000, Oliver O'Halloran wrote:
> A fairly bare-bones set of device-tree bindings so libnvdimm can be used
> on powerpc and other, less cool, device-tree based platforms.
;)
> Cc: devicetree@xxxxxxxxxxxxxxx
> Signed-off-by: Oliver O'Halloran <oohall@xxxxxxxxx>
> ---
> The current bindings are essentially this:
>
> nonvolatile-memory {
> compatible = "nonvolatile-memory", "special-memory";
> ranges;
>
> region@0 {
> compatible = "nvdimm,byte-addressable";
> reg = <0x0 0x1000>;
> };
>
> region@1000 {
> compatible = "nvdimm,byte-addressable";
> reg = <0x1000 0x1000>;
> };
> };
This needs to have a proper binding document under
Documentation/devicetree/bindings/. Something like the reserved-memory
bdings would be a good template.
If we want thet "nvdimm" vendor-prefix, that'll have to be reserved,
too (see Documentation/devicetree/bindings/vendor-prefixes.txt).
What is "special-memory"? What other memory types would be described
here?
What exacctly does "nvdimm,byte-addressable" imply? I suspect that you
also expect such memory to be compatible with mappings using (some)
cacheable attributes?
Perhaps the byte-addressable property should be a boolean property on
the region, rather than part of the compatible string.
> To handle interleave sets, etc the plan was the add an extra property with the
> interleave stride and a "mapping" property with <&DIMM, dimm-start-offset>
> tuples for each dimm in the interleave set. Block MMIO regions can be added
> with a different compatible type, but I'm not too concerned with them for
> now.
Sorry, I'm not too familiar with nonvolatile memory. What are interleave
sets?
What are block MMIO regions?
Is there any documentation one can refer to for any of this?
[...]
> +static const struct of_device_id of_nvdimm_bus_match[] = {
> + { .compatible = "nonvolatile-memory" },
> + { .compatible = "special-memory" },
> + { },
> +};
Why both? Is the driver handling other "special-memory"?
Thanks,
Mark.
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