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Date:   Wed, 13 Sep 2023 12:39:45 +0530
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Subject: Re: [PATCH v5 06/17] soc: qcom: Add Qualcomm APSS minidump kernel
 driver
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To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        <corbet@lwn.net>, <agross@kernel.org>, <andersson@kernel.org>,
        <konrad.dybcio@linaro.org>, <robh+dt@kernel.org>,
        <krzysztof.kozlowski+dt@linaro.org>, <conor+dt@kernel.org>,
        <keescook@chromium.org>, <tony.luck@intel.com>,
        <gpiccoli@igalia.com>, <mathieu.poirier@linaro.org>,
        <catalin.marinas@arm.com>, <will@kernel.org>,
        <linus.walleij@linaro.org>, <andy.shevchenko@gmail.com>,
        <vigneshr@ti.com>, <nm@ti.com>, <matthias.bgg@gmail.com>,
        <kgene@kernel.org>, <alim.akhtar@samsung.com>,
        <bmasney@redhat.com>, <quic_tsoni@quicinc.com>
CC:     <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
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References: <1694290578-17733-1-git-send-email-quic_mojha@quicinc.com>
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 <94770fc6-7d72-8283-5858-786685620d5c@linaro.org>
From:   Mukesh Ojha <quic_mojha@quicinc.com>
In-Reply-To: <94770fc6-7d72-8283-5858-786685620d5c@linaro.org>
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On 9/12/2023 3:24 PM, Krzysztof Kozlowski wrote:
> On 12/09/2023 11:26, Mukesh Ojha wrote:
>>>
>>>> +		return -EINVAL;
>>>> +	}
>>>> +
>>>> +	mutex_init(&md->md_lock);
>>>> +	ret = qcom_apss_md_table_init(md, &mdgtoc->subsystems[MINIDUMP_APSS_DESC]);
>>>> +	if (ret) {
>>>> +		dev_err(md->dev, "apss minidump initialization failed: %d\n", ret);
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	/* First entry would be ELF header */
>>>> +	ret = qcom_md_add_elfheader(md);
>>>> +	if (ret) {
>>>> +		dev_err(md->dev, "Failed to add elf header: %d\n", ret);
>>>> +		memset(md->apss_data->md_ss_toc, 0, sizeof(struct minidump_subsystem));
>>>
>>> Why do you need it?
>>
>> Earlier, i got comment about clearing the SS TOC(subsystem table of
>> content) which is shared with other SS and it will have stale values.
> 
> OK, but then the entire code is poorly readable. First, any cleanup of
> qcom_apss_md_table_init() should be named similarly, e.g.
> qcom_apss_md_table_clean() or qcom_apss_md_table_exit() or whatever
> seems feasible.

ACK on this.

> 
> Second, shouldn't writing to shared memory be the last step? Step which
> cannot fail and there is no cleanup afterwards (like
> platform_set_drvdata)? I don't enjoy looking at this interface...

It can be done, if i shift adding elf header as first thing to first
caller of qcom_minidump_region_register() but then i would have to 
remove qcom_ramoops_minidump() from this probe in 11/17 patch.

-Mukesh
> 
> 
> 
> Best regards,
> Krzysztof
>