On Wed, 2017-06-28 at 17:50 -0500, Rob Herring wrote:

quoted

quoted

quoted

+                       #clock-cells = <0>;
+                       compatible = "fixed-clock";
+                       clock-frequency = <1000000000>;
+               };
+
+               core_intc: archs-intc@cpu {

cpu is not a valid unit-address. How are these interrupt
controllers addressed?

We have per-core INTC so each core communicates to its own INTC and
there's no way
for any core to talk with INTC of another core.

But then we have the next level INTC which is IDU (Interrupt
Distribution Unit)
which dispatches "common" IRQs to different upstream per-core INTC,
see below its node. 

Okay, I'd just do "cpu-interrupt-controller" for the node name then. 
There doesn't seem to be an easy way to use just "interrupt-
controller" 
since you have 2 nodes at the same level and no unit-address (i.e. a 
reg property).

To be more clarify, what is better way do describe such hardware in
device tree?

-------------    -------------  
| cpu core 0|    | cpu core 1|  
-------------    -------------  
| interrupt |    | interrupt |  
| controller|    | controller|  
|     0     |    |     1     |  
-------------    -------------  
      ^                ^
      |                |
             -----------
      |      |
----------------
|   interrupt  |
| distribution |
|     unit     |
----------------
      ^
      |
      |<--other devices interrupt lines

We can't just create a node for each core interrupt controller because
we wouldn't able to specify which one is parent for interrupt
distribution unit:

------------>>>-------------
cpus {
    cpu@0 { intc@0 };
    cpu@1 { intc@1 };
};

interrupt-distribution-unit {
    interrupt-parent = ????
};
------------>>>-------------

Should we simply create one core interrupt controller node for all cpus
(instead of one per each cpu core), or where is a better option?

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