On 08/15/2013 04:42 AM, Lorenzo Pieralisi wrote:
> The advent of multi-cluster ARM systems requires a mechanism to describe
> how in hierarchical terms CPUs are connected in ARM SoCs so that the kernel
> can initialize and map resources like IRQs and memory space to specific
> group(s) of CPUs.
>
> The CPU topology is made up of multiple hierarchy levels whose bottom
> layers (aka leaf nodes in device tree syntax) contain links to the HW
> CPUs in the system.
>
> The topology bindings are generic for both 32-bit and 64-bit systems and
> lay the groundwork on top of which affinity schemes can be built.
By affinity schemes, you mean further bindings? Do we need this binding
until that point?
As is, I don't have much comment.
[snip]
> +Example 3 (ARM 32-bit, cortex-a8 single core):
> +
> +cpus {
> + #size-cells = <0>;
> + #address-cells = <1>;
> +
> + cpu-map {
> + cluster0 {
> + core0 {
> + cpu = <&CPU0>;
> + };
> + };
> + };
This example seems utterly pointless. I think we should be specific that
single core does not contain a cpu-map. I suppose we could have a
threaded, single core case, but let's address that if we ever do.
Rob
> +
> + CPU0: cpu@0 {
> + device_type = "cpu";
> + compatible = "arm,cortex-a8";
> + reg = <0x0>;
> + };
> +};
> +
> +===============================================================================
> +[1] ARM Linux kernel documentation
> + Documentation/devicetree/bindings/arm/cpus.txt
>
--
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
