linux-kernel - Re: [PATCH v10 1/2] cpufreq: Add Kryo CPU scaling driver

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Message-ID: <20180523100316.27m4epl7deitfrnt@vireshk-i7>
Date:   Wed, 23 May 2018 15:33:16 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Ilia Lin <ilialin@...eaurora.org>
Cc:     vireshk@...nel.org, nm@...com, sboyd@...nel.org, robh@...nel.org,
        mark.rutland@....com, rjw@...ysocki.net, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v10 1/2] cpufreq: Add Kryo CPU scaling driver

On 23-05-18, 12:40, Ilia Lin wrote:
> In Certain QCOM SoCs like apq8096 and msm8996 that have KRYO processors,
> the CPU frequency subset and voltage value of each OPP varies
> based on the silicon variant in use. Qualcomm Process Voltage Scaling Tables
> defines the voltage and frequency value based on the msm-id in SMEM
> and speedbin blown in the efuse combination.
> The qcom-cpufreq-kryo driver reads the msm-id and efuse value from the SoC
> to provide the OPP framework with required information.
> This is used to determine the voltage and frequency value for each OPP of
> operating-points-v2 table when it is parsed by the OPP framework.
> 
> Signed-off-by: Ilia Lin <ilialin@...eaurora.org>

Well I gave you an Ack and you should have kept it here :(

> +static int __init qcom_cpufreq_kryo_driver_init(void)
> +{
> +	struct opp_table *opp_tables[NR_CPUS] = {0};
> +	enum _msm8996_version msm8996_version;
> +	struct nvmem_cell *speedbin_nvmem;
> +	struct platform_device *pdev;
> +	struct device_node *np;
> +	struct device *cpu_dev;
> +	unsigned cpu;
> +	u8 *speedbin;
> +	u32 versions;
> +	size_t len;
> +	int ret;
> +
> +	cpu_dev = get_cpu_device(0);
> +	if (NULL == cpu_dev)
> +		return -ENODEV;
> +
> +	msm8996_version = qcom_cpufreq_kryo_get_msm_id();
> +	if (NUM_OF_MSM8996_VERSIONS == msm8996_version) {
> +		dev_err(cpu_dev, "Not Snapdragon 820/821!");
> +		return -ENODEV;
> +	}
> +
> +	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
> +	if (IS_ERR(np))
> +		return PTR_ERR(np);
> +
> +	if (!of_device_is_compatible(np, "operating-points-v2-kryo-cpu")) {
> +		ret = -ENOENT;
> +		goto free_np;

As Russell pointed out, drop this goto here and write:

                of_node_put(np);
                return -ENOENT;
        }

> +	}
> +
> +	speedbin_nvmem = of_nvmem_cell_get(np, NULL);

And do the same here unconditionally as you don't need to use np
anymore, i.e.

        of_node_put(np);

> +	if (IS_ERR(speedbin_nvmem)) {
> +		ret = PTR_ERR(speedbin_nvmem);
> +		dev_err(cpu_dev, "Could not get nvmem cell: %d\n", ret);
> +		goto free_np;
> +	}
> +
> +	speedbin = nvmem_cell_read(speedbin_nvmem, &len);
> +	nvmem_cell_put(speedbin_nvmem);
> +
> +	switch (msm8996_version) {
> +	case MSM8996_V3:
> +		versions = 1 << (unsigned int)(*speedbin);
> +		break;
> +	case MSM8996_SG:
> +		versions = 1 << ((unsigned int)(*speedbin) + 4);
> +		break;
> +	default:
> +		BUG();
> +		break;
> +	}
> +
> +	for_each_possible_cpu(cpu) {
> +		cpu_dev = get_cpu_device(cpu);
> +		if (NULL == cpu_dev) {
> +			ret = -ENODEV;
> +			goto free_opp;
> +		}
> +
> +		opp_tables[cpu] = dev_pm_opp_set_supported_hw(cpu_dev,
> +							      &versions, 1);
> +		if (IS_ERR(opp_tables[cpu])) {
> +			ret = PTR_ERR(opp_tables[cpu]);
> +			dev_err(cpu_dev, "Failed to set supported hardware\n");
> +			goto free_opp;
> +		}
> +	}
> +
> +	pdev = platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
> +	if (!IS_ERR(pdev))
> +		return 0;
> +
> +	ret = PTR_ERR(pdev);
> +	dev_err(cpu_dev, "Failed to register platform device\n");
> +
> +free_opp:
> +	for_each_possible_cpu(cpu) {
> +		if (IS_ERR_OR_NULL(opp_tables[cpu]))
> +			break;
> +		dev_pm_opp_put_supported_hw(opp_tables[cpu]);
> +	}
> +free_np:
> +	of_node_put(np);

And then you can remove the label and above statement.

> +
> +	return ret;
> +}
> +late_initcall(qcom_cpufreq_kryo_driver_init);
> +
> +MODULE_DESCRIPTION("Qualcomm Technologies, Inc. Kryo CPUfreq driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 1.9.1

-- 
viresh