linux-kernel - Re: [PATCH v2 1/4] dt-bindings: Introduce soc sleep stats bindings for Qualcomm SoCs

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Message-ID: <b2ec702c-67e9-2473-a5d4-1bb53d9907cd@codeaurora.org>
Date:   Fri, 6 Mar 2020 11:52:59 +0530
From:   Maulik Shah <mkshah@...eaurora.org>
To:     Stephen Boyd <swboyd@...omium.org>, bjorn.andersson@...aro.org,
        evgreen@...omium.org, mka@...omium.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        agross@...nel.org, dianders@...omium.org, rnayak@...eaurora.org,
        ilina@...eaurora.org, lsrao@...eaurora.org,
        Mahesh Sivasubramanian <msivasub@...eaurora.org>,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v2 1/4] dt-bindings: Introduce soc sleep stats bindings
 for Qualcomm SoCs


On 2/28/2020 10:17 PM, Stephen Boyd wrote:
> Quoting Maulik Shah (2020-02-21 00:49:43)
>> diff --git a/Documentation/devicetree/bindings/soc/qcom/soc-sleep-stats.yaml b/Documentation/devicetree/bindings/soc/qcom/soc-sleep-stats.yaml
>> new file mode 100644
>> index 00000000..50352a4
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/soc/qcom/soc-sleep-stats.yaml
>> @@ -0,0 +1,47 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/bindings/soc/qcom/soc-sleep-stats.yaml#
> Drop 'bindings' from above?
Done.
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Qualcomm Technologies, Inc. (QTI) SoC sleep stats bindings
>> +
>> +maintainers:
>> +  - Maulik Shah <mkshah@...eaurora.org>
>> +  - Lina Iyer <ilina@...eaurora.org>
>> +
>> +description: |
>> +  Always On Processor/Resource Power Manager maintains statistics of the SoC
>> +  sleep modes involving powering down of the rails and oscillator clock.
>> +
>> +  Statistics includes SoC sleep mode type, number of times low power mode were
>> +  entered, time of last entry, time of last exit and accumulated sleep duration.
>> +  SoC sleep stats driver provides debugfs interface to show this information.
> Please remove this last line. It is a Linuxism that doesn't belong in DT
> bindings. And then make it one paragraph and drop the | because
> formatting doesn't need to be maintained.
Done.
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - qcom,rpmh-sleep-stats
>> +      - qcom,rpm-sleep-stats
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +
>> +examples:
>> +  # Example of rpmh sleep stats
>> +  - |
>> +    rpmh_sleep_stats: soc-sleep-stats@...0000 {
>> +      compatible = "qcom,rpmh-sleep-stats";
>> +      reg = <0 0xc3f0000 0 0x400>;
>> +    };
> I see that on sc7180 aoss-qmp is overlapping with this region.
>
>
> 	aoss_qmp: qmp@...0000 {
> 		compatible = "qcom,sc7180-aoss-qmp";
> 		reg = <0 0x0c300000 0 0x100000>;
>
> So is this register region really something more like a TCM or RAM area
> where rpmh combines multiple software concepts into one hardware memory
> region? The aoss-qmp driver talks about message RAM, so I think this
> sleep stats stuff is a carveout of the RPMh message RAM. It seems OK if
> we want to split that message RAM up into multiple DT nodes, but then
> we'll need to reduce the reg size for the aoss-qmp node.
Yes, i discussed this long back with bjorn, we will limit aoss_qmp size to 0x400.
Will include in next revision in DTSI change.
> Finally, the node name 'soc-sleep-stats' is generic, but I wonder why we
> couldn't name the node 'tcm' or 'memory' or 'msgram'. Similarly for the
> qmp node it fits better DT style to have the node be something generic.
following DTSI change in this series has comment to drop the label, since no one
references this node. if we drop label than just naming it msgram@...0000 will also
be too generic IMO.

To address both the comments i am planning to drop label and also soc-sleep-stats
and just keep rpmh_sleep_stats@...0000.

Thanks,
Maulik

>> +  # Example of rpm sleep stats
>> +  - |
>> +    rpm_sleep_stats: soc-sleep-stats@...0000 {
>> +      compatible = "qcom,rpm-sleep-stats";
>> +      reg = <0 0x04690000 0 0x400>;
>> +    };
>> +...

-- 
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