Re: [PATCH v4 1/5] dt-bindings: add SMP enable-method for Broadcom NSP

[Kapil Hali]

Hi Rob,

On 12/2/2015 8:56 PM, Rob Herring wrote:
> On Tue, Dec 01, 2015 at 11:24:05AM -0500, Kapil Hali wrote:
>> Add a compatible string "brcm,bcm-nsp-smp" for Broadcom's
>> Northstar Plus CPU to the 32-bit ARM CPU device tree binding
>> documentation file and create a new binding documentation for
>> Northstar Plus CPU.
>>
>> Signed-off-by: Kapil Hali <kapilh@xxxxxxxxxxxx>
>> ---
>>  .../bindings/arm/bcm/brcm,nsp-cpu-method.txt       | 39 ++++++++++++++++++++++
>>  Documentation/devicetree/bindings/arm/cpus.txt     |  1 +
>>  2 files changed, 40 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/arm/bcm/brcm,nsp-cpu-method.txt
>>
>> diff --git a/Documentation/devicetree/bindings/arm/bcm/brcm,nsp-cpu-method.txt b/Documentation/devicetree/bindings/arm/bcm/brcm,nsp-cpu-method.txt
>> new file mode 100644
>> index 0000000..bf08872
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/bcm/brcm,nsp-cpu-method.txt
>> @@ -0,0 +1,39 @@
>> +Broadcom Northstar Plus SoC CPU Enable Method
>> +---------------------------------------------
>> +This binding defines the enable method used for starting secondary
>> +CPUs in the following Broadcom SoCs:
>> +  BCM58522, BCM58525, BCM58535, BCM58622, BCM58623, BCM58625, BCM88312
>> +
>> +The enable method is specified by defining the following required
>> +properties in the "cpus" device tree node:
>> +  - enable-method = "brcm,bcm-nsp-smp";
>> +  - secondary-boot-reg = <...>;
> 
> Both of these are supposed to be per cpu core.

'enable-method' if not found in 'cpu' node is looked at in the 'cpus' 
node. Except for two-three SoC families, 'enable-method' is within 
'cpus' node. Is my interpretation incorrect? Did I miss anything here?

> 
> Rob
> 
>> +
>> +The secondary-boot-reg property is a u32 value that specifies the
>> +physical address of the register which should hold the common
>> +entry point for a secondary CPU. This entry is cpu node specific
>> +and should be added per cpu. E.g., in case of NSP (BCM58625) which
>> +is a dual core CPU SoC, this entry should be added to cpu1 node.
>> +
>> +
>> +Example:
>> +	cpus {
>> +		#address-cells = <1>;
>> +		#size-cells = <0>;
>> +		enable-method = "brcm,bcm-nsp-smp";
>> +
>> +		cpu0: cpu@0 {
>> +			device_type = "cpu";
>> +			compatible = "arm,cortex-a9";
>> +			next-level-cache = <&L2>;
>> +			reg = <0>;
>> +		};
>> +
>> +		cpu1: cpu@1 {
>> +			device_type = "cpu";
>> +			compatible = "arm,cortex-a9";
>> +			next-level-cache = <&L2>;
>> +			reg = <1>;
>> +			secondary-boot-reg = <0xffff042c>;
>> +		};
>> +	};
>> diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt
>> index 3a07a87..d191554 100644
>> --- a/Documentation/devicetree/bindings/arm/cpus.txt
>> +++ b/Documentation/devicetree/bindings/arm/cpus.txt
>> @@ -190,6 +190,7 @@ nodes to be present and contain the properties described below.
>>  			    "allwinner,sun6i-a31"
>>  			    "allwinner,sun8i-a23"
>>  			    "arm,psci"
>> +			    "brcm,bcm-nsp-smp"
>>  			    "brcm,brahma-b15"
>>  			    "marvell,armada-375-smp"
>>  			    "marvell,armada-380-smp"
>> -- 
>> 2.1.0
>>
> 
Thanks,
Kapil
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