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Message-ID: <6000d205-5c1d-f342-7d2e-1399ac1cb825@quicinc.com>
Date:   Wed, 12 Apr 2023 19:55:19 +0530
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Subject: Re: [PATCH V2 2/3] soc: qcom: boot_stat: Add Driver Support for Boot
 Stats
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To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Konrad Dybcio <konrad.dybcio@somainline.org>,
        "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Rob Herring <robh+dt@kernel.org>
CC:     <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <linux-arm-msm@vger.kernel.org>,
        <devicetree@vger.kernel.org>, Sibi Sankar <quic_sibis@quicinc.com>,
        Rajendra Nayak <quic_rjendra@quicinc.com>
References: <cover.1680874520.git.quic_schowdhu@quicinc.com>
 <5eeeb46e9b3f61656a37cb77c2ad6a04e383c16d.1680874520.git.quic_schowdhu@quicinc.com>
 <d05e1184-ead4-3f80-4c06-ff757a10ba3b@linaro.org>
From:   Souradeep Chowdhury <quic_schowdhu@quicinc.com>
In-Reply-To: <d05e1184-ead4-3f80-4c06-ff757a10ba3b@linaro.org>
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On 4/12/2023 1:51 PM, Krzysztof Kozlowski wrote:
> On 07/04/2023 16:04, Souradeep Chowdhury wrote:
>> All of Qualcomm's proprietary Android boot-loaders capture boot time
>> stats, like the time when the bootloader started execution and at what
>> point the bootloader handed over control to the kernel etc. in the IMEM
>> region. This information is captured in a specific format by this driver
>> by mapping a structure to the IMEM memory region and then accessing the
>> members of the structure to print the information. This information is
>> useful in verifying if the existing boot KPIs have regressed or not.
>> A sample log in SM8450(waipio) device is as follows:-
>>
> 
> 
>> +
>> +static int boot_stats_probe(struct platform_device *pdev)
>> +{
>> +	struct device_node *np_mpm2;
>> +	struct device *boot_stat = &pdev->dev;
>> +
>> +	boot_stats = of_iomap(boot_stat->of_node->child, 0);
>> +	if (!boot_stats)
>> +		return dev_err_probe(&pdev->dev, -ENOMEM,
>> +					"failed to map imem region\n");
>> +
>> +	np_mpm2 = of_find_compatible_node(NULL, NULL,
>> +					  "qcom,mpm2-sleep-counter");
> 
> This is undocumented and non-existing compatible. No, we cannot take this.
> 
> Also, referencing other nodes should be with phandles, not compatibles.

Ack. This will be dropped in the next version as we are not printing the
current kernel timestamp.

> 
> 
> Best regards,
> Krzysztof
>