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Message-ID: <0eeef9c4-14c0-8283-803b-4684854d4be6@quicinc.com>
Date:   Tue, 12 Sep 2023 14:56:44 +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>,
        <linux-arm-msm@vger.kernel.org>, <linux-hardening@vger.kernel.org>,
        <linux-remoteproc@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-gpio@vger.kernel.org>, <linux-mediatek@lists.infradead.org>,
        <linux-samsung-soc@vger.kernel.org>, <kernel@quicinc.com>
References: <1694290578-17733-1-git-send-email-quic_mojha@quicinc.com>
 <1694290578-17733-7-git-send-email-quic_mojha@quicinc.com>
 <3bb1e84f-3b65-0596-1b6b-6decb0ff53cc@linaro.org>
From:   Mukesh Ojha <quic_mojha@quicinc.com>
In-Reply-To: <3bb1e84f-3b65-0596-1b6b-6decb0ff53cc@linaro.org>
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Thanks for your time in reviewing this.

On 9/11/2023 4:31 PM, Krzysztof Kozlowski wrote:
> On 09/09/2023 22:16, Mukesh Ojha wrote:
>> Minidump is a best effort mechanism to collect useful and predefined
>> data for first level of debugging on end user devices running on
>> Qualcomm SoCs. It is built on the premise that System on Chip (SoC)
>> or subsystem part of SoC crashes, due to a range of hardware and
>> software bugs. Hence, the ability to collect accurate data is only
>> a best-effort. The data collected could be invalid or corrupted,
>> data collection itself could fail, and so on.
> 
> ...
> 
>> +static int qcom_apss_md_table_init(struct minidump *md,
>> +				   struct minidump_subsystem *mdss_toc)
>> +{
>> +	struct minidump_ss_data *mdss_data;
>> +
>> +	mdss_data = devm_kzalloc(md->dev, sizeof(*mdss_data), GFP_KERNEL);
>> +	if (!mdss_data)
>> +		return -ENOMEM;
>> +
>> +	mdss_data->md_ss_toc = mdss_toc;
>> +	mdss_data->md_regions = devm_kcalloc(md->dev, MAX_NUM_ENTRIES,
>> +					     sizeof(struct minidump_region),
>> +					     GFP_KERNEL);
>> +	if (!mdss_data->md_regions)
>> +		return -ENOMEM;
>> +
>> +	mdss_toc = mdss_data->md_ss_toc;
>> +	mdss_toc->regions_baseptr = cpu_to_le64(virt_to_phys(mdss_data->md_regions));
>> +	mdss_toc->enabled = cpu_to_le32(MINIDUMP_SS_ENABLED);
>> +	mdss_toc->status = cpu_to_le32(1);
>> +	mdss_toc->region_count = cpu_to_le32(0);
>> +
>> +	/* Tell bootloader not to encrypt the regions of this subsystem */
>> +	mdss_toc->encryption_status = cpu_to_le32(MINIDUMP_SS_ENCR_DONE);
>> +	mdss_toc->encryption_required = cpu_to_le32(MINIDUMP_SS_ENCR_NOTREQ);
>> +
>> +	md->apss_data = mdss_data;
>> +
>> +	return 0;
>> +}
>> +
>> +static int qcom_apss_minidump_probe(struct platform_device *pdev)
>> +{
>> +	struct minidump_global_toc *mdgtoc;
>> +	struct minidump *md;
>> +	size_t size;
>> +	int ret;
>> +
>> +	md = devm_kzalloc(&pdev->dev, sizeof(struct minidump), GFP_KERNEL);
> 
> sizeof(*)
> 
> Didn't you get such comments already?

Ok, will fix this, no i have not got such comments as of yet.
Any reason of using this way?

> 
> 
>> +	if (!md)
>> +		return -ENOMEM;
>> +
>> +	md->dev = &pdev->dev;
>> +	mdgtoc = qcom_smem_get(QCOM_SMEM_HOST_ANY, SBL_MINIDUMP_SMEM_ID, &size);
>> +	if (IS_ERR(mdgtoc)) {
>> +		ret = PTR_ERR(mdgtoc);
>> +		dev_err(md->dev, "Couldn't find minidump smem item: %d\n", ret);
>> +		return ret;
> 
> The syntax is:
> return dev_err_probe

ACK.

> 
>> +	}
>> +
>> +	if (size < sizeof(*mdgtoc) || !mdgtoc->status) {
>> +		dev_err(md->dev, "minidump table is not initialized: %d\n", ret);
> 
> ret is uninitialized here. Please use automated tools for checking your
> code:
> coccinelle, smatch and sparse

Thanks.

> 
>> +		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.

> 
>> +		return ret;
>> +	}
>> +
>> +	platform_set_drvdata(pdev, md);
>> +
>> +	return ret;
>> +}
>> +
>> +static int qcom_apss_minidump_remove(struct platform_device *pdev)
>> +{
>> +	struct minidump *md = platform_get_drvdata(pdev);
>> +	struct minidump_ss_data *mdss_data;
>> +
>> +	mdss_data = md->apss_data;
>> +	memset(mdss_data->md_ss_toc, cpu_to_le32(0), sizeof(struct minidump_subsystem));
> 
> Why do you need it?

Same as above.

> 
>> +	md = NULL;
> 
> That's useless assignment.

Ok.

> 
>> +
>> +	return 0;
>> +}
>> +
>> +static struct platform_driver qcom_minidump_driver = {
>> +	.probe = qcom_apss_minidump_probe,
>> +	.remove = qcom_apss_minidump_remove,
>> +	.driver  = {
>> +		.name = "qcom-minidump-smem",
>> +	},
>> +};
>> +
>> +module_platform_driver(qcom_minidump_driver);
>> +
>> +MODULE_DESCRIPTION("Qualcomm APSS minidump driver");
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS("platform:qcom-minidump-smem");
> 
> Add a proper ID table instead of re-inventing it with module aliases.

Ok.

-Mukesh

> 
> Best regards,
> Krzysztof
>