linux-kernel - Re: [PATCH V2 2/3] soc: qcom: boot_stat: Add Driver Support for Boot Stats

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Message-ID: <6000d205-5c1d-f342-7d2e-1399ac1cb825@quicinc.com>
Date:   Wed, 12 Apr 2023 19:55:19 +0530
From:   Souradeep Chowdhury <quic_schowdhu@...cinc.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Rob Herring <robh+dt@...nel.org>
CC:     <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <devicetree@...r.kernel.org>, Sibi Sankar <quic_sibis@...cinc.com>,
        Rajendra Nayak <quic_rjendra@...cinc.com>
Subject: Re: [PATCH V2 2/3] soc: qcom: boot_stat: Add Driver Support for Boot
 Stats



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
>