Re: [PATCH 2/7] arm/dts: OMAP3: Add mpu and iva nodes

[Mitch Bradley <wmb@firmworks.com>]

On 9/5/2011 7:23 AM, Arnd Bergmann wrote:
> On Monday 05 September 2011, Cousson, Benoit wrote:
>> Yeah, I saw that in the "cpus" node documentation. My point here is that
>> I do need to represent the MPU subsystem that will contain the cpus. And
>> thus the Cortex is inside the MPU subsystem.


The device tree hierarchy does not represent "containment", but rather 
addressing from the standpoint of a program running on a CPU.

 From that viewpoint, it might be better to have a phandle reference to 
the mpu in each CPU node.

>>
>> I can potentially keep the CPUs inside the cpus node, and just represent
>> the mpu node inside the soc, with potentially some phandle to the real
>> cpu nodes.
>>
>> Something like that:
>>
>> cpus {
>>          cpu0: cpu@0 {
>>                          compatible = "arm,cortex-a8";
>>          };
>> };
>>
>> [...]
>>
>> soc {
>>          compatible = "ti,omap-infra";
>>          mpu {
>>                  compatible = "ti,omap3-mpu";
>>                  hwmods = "mpu";
>>                  cpu@0 {
>>                          phandle =<&cpu0>;
>>                          [...]
>>                  };
>>          };
>> };
>
> Yes, that looks good. I wouldn't name the attribute "phandle" if I could
> think of anything better (which I can't at the moment).
>
> 	Arnd
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