Re: [PATCH 02/11] devicetree: bindings: Document Qualcomm cpus and enable-method

From: Kumar Gala
Date: Tue Nov 05 2013 - 12:12:39 EST



On Nov 4, 2013, at 11:36 AM, Stephen Boyd wrote:

> On 11/01, Rob Herring wrote:
>> On Fri, Nov 1, 2013 at 5:08 PM, Stephen Boyd <sboyd@xxxxxxxxxxxxxx> wrote:
>>> From: Rohit Vaswani <rvaswani@xxxxxxxxxxxxxx>
>>>
>>> Scorpion and Krait are Qualcomm cpus. These cpus don't use the
>>> spin-table enable-method. Instead they rely on mmio register
>>> accesses to enable power and clocks to bring CPUs out of reset.
>>>
>>> Cc: <devicetree@xxxxxxxxxxxxxxx>
>>> Signed-off-by: Rohit Vaswani <rvaswani@xxxxxxxxxxxxxx>
>>> [sboyd: Split off into separate patch, renamed method to
>>> qcom,mmio]
>>> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
>>> ---
>>>
>>> This slightly conflicts with my krait EDAC series.
>>>
>>> Documentation/devicetree/bindings/arm/cpus.txt | 3 +++
>>> 1 file changed, 3 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt
>>> index 37258f9..e2969fa2 100644
>>> --- a/Documentation/devicetree/bindings/arm/cpus.txt
>>> +++ b/Documentation/devicetree/bindings/arm/cpus.txt
>>> @@ -44,6 +44,8 @@ For the ARM architecture every CPU node must contain the following properties:
>>> "marvell,mohawk"
>>> "marvell,xsc3"
>>> "marvell,xscale"
>>> + "qcom,scorpion"
>>> + "qcom,krait"
>>>
>>> And the following optional properties:
>>>
>>> @@ -52,6 +54,7 @@ And the following optional properties:
>>> different types of cpus.
>>> This should be one of:
>>> "spin-table"
>>> + "qcom,mmio"
>>
>> Not exactly specific. How would you handle variations in the enable
>> method? The mmio method to enable is tied to the core type or SOC
>> type?
>
> Variations in the enable method are handled by searching for
> another node with different compatible strings. Later on in this
> series you'll see that we search for gcc-8660, kpss-acc-v1, or
> kpps-acc-v2. Once we find one of these nodes we perform the
> correct cold boot routine.
>
> I'm actually considering renaming this to "qcom,cold-boot". We
> could further extend the enable-metho property to allow
> "qcom,warm-boot" and then for cases like kexec we could make the
> enable method be warm boot and our smp code could be smart enough
> to know to skip the whole cold boot sequence.


I think this should be more specific than just 'qcom,mmio' or 'qcom,warm-boot'. It should be 'qcom,kpss-acc-v1' or 'qcom-gcc-8660'.

- k

--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

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