On Tuesday 05 of November 2013 11:51:07 Kumar Gala wrote:

On Nov 5, 2013, at 11:44 AM, Stephen Boyd wrote:

quoted

On 11/05/13 09:13, Kumar Gala wrote:

quoted

On Nov 1, 2013, at 5:08 PM, Stephen Boyd wrote:

quoted

diff --git
a/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt
b/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt new
file mode 100644
index 0000000..ed4a9c8

--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt

@@ -0,0 +1,21 @@
+* Krait Processor Sub-system (KPSS) Application Clock Controller

(ACC)
+
+The KPSS ACC provides clock, power domain, and reset control to a
Krait CPU. +There is one ACC register region per CPU within the
KPSS remaped region as +well as an alias register region that
remaps accesses to the ACC associated +with the CPU accessing the
region.
+
+Required Properties:
+
+- compatible : Shall contain "qcom,kpss-acc-v1" or
"qcom,kpss-acc-v2".
+- reg: Specifies the base address and size of the banked register
region. +- cpu-offset : per-cpu offset used when the device is
accessed without the +		CPU remapping facilities.
+		The offset is cpu-offset + (0x10000 * cpu-nr).
+
+Example:
+
+	clock-controller at 2008000 {
+		compatible = "qcom,kpss-acc-v2";
+		reg = <0x02008000 0x1000>;
+	};

I don't get the cpu-offset business, shouldn't this just be:
	reg = <0x02008000 0x1000>, <0x02018000 0x1000>, <0x02028000 

0x1000>,

quoted

quoted

	<0x02038000 0x1000>;> 

(Sorry I forgot to add the cpu-offset to the example.)

Your reg property is one way to do it. I was following the example of
the GIC binding which just specifies the alias region of the GIC's CPU
registers and then has a cpu-offset property to describe how to reach
a
specific CPU's region.

Even in the gic's case I think we should have the reg property cover the
memory map.

The GIC case was supposed to be a hack for Exynos SoCs that do not have 
banked per-CPU registers. Currently I consider it broken, because it does 
not scale for multi cluster configurations. I believe you should consider 
the same.

IMHO the way to provide per-CPU properties should involve CPU nodes to 
make sure that the same CPU ID namespace is always used.

Best regards,
Tomasz