RE: [PATCH v8 10/15] cpufreq: Add Kryo CPU scaling driver

[<ilialin@codeaurora.org>]

Hi Viresh,

If I send patches in reply, it will produce new patches, instead of answers
in the thread. Please find below the file dump.

->cat drivers/cpufreq/qcom-cpufreq-kryo.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2018, The Linux Foundation. All rights reserved.
 */

/*
 * 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.
 */

#include <linux/cpu.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/nvmem-consumer.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/slab.h>
#include <linux/soc/qcom/smem.h>

#define MSM_ID_SMEM     137
#define SILVER_LEAD     0
#define GOLD_LEAD       2

enum _msm_id {
        MSM8996V3 = 0xF6ul,
        APQ8096V3 = 0x123ul,
        MSM8996SG = 0x131ul,
        APQ8096SG = 0x138ul,
};

enum _msm8996_version {
        MSM8996_V3,
        MSM8996_SG,
        NUM_OF_MSM8996_VERSIONS,
};

static enum _msm8996_version __init qcom_cpufreq_kryo_get_msm_id(void)
{
        size_t len;
        u32 *msm_id;
        enum _msm8996_version version;

        msm_id = qcom_smem_get(QCOM_SMEM_HOST_ANY, MSM_ID_SMEM, &len);
        /* The first 4 bytes are format, next to them is the actual msm-id
*/
        msm_id++;

        switch ((enum _msm_id)*msm_id) {
        case MSM8996V3:
        case APQ8096V3:
                version = MSM8996_V3;
                break;
        case MSM8996SG:
        case APQ8096SG:
                version = MSM8996_SG;
                break;
        default:
                version = NUM_OF_MSM8996_VERSIONS;
        }

        return version;
}

static int __init qcom_cpufreq_kryo_driver_init(void)
{
        struct device *cpu_dev_silver, *cpu_dev_gold;
        struct opp_table *opp_silver, *opp_gold;
        enum _msm8996_version msm8996_version;
        struct nvmem_cell *speedbin_nvmem;
        struct platform_device *pdev;
        struct device_node *np;
        u8 *speedbin;
        u32 versions;
        size_t len;
        int ret;

        cpu_dev_silver = get_cpu_device(SILVER_LEAD);
        if (IS_ERR_OR_NULL(cpu_dev_silver))
                return PTR_ERR(cpu_dev_silver);

        cpu_dev_gold = get_cpu_device(SILVER_LEAD);
        if (IS_ERR_OR_NULL(cpu_dev_gold))
                return PTR_ERR(cpu_dev_gold);

        msm8996_version = qcom_cpufreq_kryo_get_msm_id();
        if (NUM_OF_MSM8996_VERSIONS == msm8996_version) {
                dev_err(cpu_dev_silver, "Not Snapdragon 820/821!");
                return -ENODEV;
        }

        np = dev_pm_opp_of_get_opp_desc_node(cpu_dev_silver);
        if (IS_ERR_OR_NULL(np))
                return PTR_ERR(np);

        if (!of_device_is_compatible(np, "operating-points-v2-kryo-cpu")) {
                ret = -ENOENT;
                goto free_np;
        }

        speedbin_nvmem = of_nvmem_cell_get(np, NULL);
        if (IS_ERR(speedbin_nvmem)) {
                ret = PTR_ERR(speedbin_nvmem);
                dev_err(cpu_dev_silver, "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;
        }

        opp_silver =
dev_pm_opp_set_supported_hw(cpu_dev_silver,&versions,1);
        if (IS_ERR(opp_silver)) {
                dev_err(cpu_dev_silver, "Failed to set supported
hardware\n");
                ret = PTR_ERR(opp_silver);
                goto free_np;
        }

        opp_gold = dev_pm_opp_set_supported_hw(cpu_dev_gold,&versions,1);
        if (IS_ERR(opp_gold)) {
                dev_err(cpu_dev_gold, "Failed to set supported hardware\n");
                ret = PTR_ERR(opp_gold);
                goto free_opp_silver;
        }

        pdev = platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
        if (!IS_ERR_OR_NULL(pdev))
                return 0;

        ret = PTR_ERR(pdev);
        dev_err(cpu_dev_silver, "Failed to register platform device\n");
        dev_pm_opp_put_supported_hw(opp_gold);

free_opp_silver:
        dev_pm_opp_put_supported_hw(opp_silver);

free_np:
        of_node_put(np);

        return ret;
}
late_initcall(qcom_cpufreq_kryo_driver_init);

MODULE_DESCRIPTION("Qualcomm Technologies, Inc. Kryo CPUfreq driver");
MODULE_LICENSE("GPL v2");

> -----Original Message-----
> From: Viresh Kumar <viresh.kumar@linaro.org>
> Sent: Friday, May 18, 2018 04:46
> To: Ilia Lin <ilialin@codeaurora.org>
> Cc: mturquette@baylibre.com; sboyd@kernel.org; robh@kernel.org;
> mark.rutland@arm.com; nm@ti.com; lgirdwood@gmail.com;
> broonie@kernel.org; andy.gross@linaro.org; david.brown@linaro.org;
> catalin.marinas@arm.com; will.deacon@arm.com; rjw@rjwysocki.net; linux-
> clk@vger.kernel.org; devicetree@vger.kernel.org; linux-
> kernel@vger.kernel.org; linux-pm@vger.kernel.org; linux-arm-
> msm@vger.kernel.org; linux-soc@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; rnayak@codeaurora.org;
> amit.kucheria@linaro.org; nicolas.dechesne@linaro.org;
> celster@codeaurora.org; tfinkel@codeaurora.org
> Subject: Re: [PATCH v8 10/15] cpufreq: Add Kryo CPU scaling driver
> 
> On 17-05-18, 14:19, Ilia Lin wrote:
> > +static int __init qcom_cpufreq_kryo_driver_init(void)
> > +{
> > +	size_t len;
> > +	int ret = 0;
> > +	u32 versions;
> > +	enum _msm8996_version msm8996_version;
> > +	u8 *speedbin;
> > +	struct device *cpu_dev_silver, *cpu_dev_gold;
> > +	struct device_node *np;
> > +	struct nvmem_cell *speedbin_nvmem;
> > +	struct platform_device *pdev;
> > +	struct opp_table *opp_silver = NULL;
> > +	struct opp_table *opp_gold = NULL;
> 
> No need to initialize them and you may want to arrange all above in
> decreasing order of their length.
> 
> > +
> > +	cpu_dev_silver = get_cpu_device(SILVER_LEAD);
> > +	if (IS_ERR_OR_NULL(cpu_dev_silver))
> > +		return PTR_ERR(cpu_dev_silver);
> > +
> > +	cpu_dev_gold = get_cpu_device(SILVER_LEAD);
> > +	if (IS_ERR_OR_NULL(cpu_dev_gold))
> > +		return PTR_ERR(cpu_dev_gold);
> > +
> > +	msm8996_version = qcom_cpufreq_kryo_get_msm_id();
> > +	if (NUM_OF_MSM8996_VERSIONS == msm8996_version) {
> > +		dev_err(cpu_dev_silver, "Not Snapdragon 820/821!");
> > +		return -ENODEV;
> > +	}
> > +
> > +	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev_silver);
> > +	if (IS_ERR_OR_NULL(np))
> > +		return PTR_ERR(np);
> > +
> > +	if (!of_device_is_compatible(np, "operating-points-v2-kryo-cpu")) {
> > +		ret = -ENOENT;
> > +		goto free_np;
> > +	}
> > +
> > +	speedbin_nvmem = of_nvmem_cell_get(np, NULL);
> > +	if (IS_ERR(speedbin_nvmem)) {
> > +		ret = PTR_ERR(speedbin_nvmem);
> > +		dev_err(cpu_dev_silver, "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;
> > +	}
> > +
> > +	opp_silver =
> dev_pm_opp_set_supported_hw(cpu_dev_silver,&versions,1);
> > +	if (IS_ERR_OR_NULL(opp_silver)) {
> 
> This API doesn't return NULL and so IS_ERR() would be sufficient.
> 
> > +		dev_err(cpu_dev_silver, "Failed to set supported
> hardware\n");
> > +		ret = PTR_ERR(opp_silver);
> > +		goto free_np;
> > +	}
> > +
> > +	opp_gold =
> dev_pm_opp_set_supported_hw(cpu_dev_gold,&versions,1);
> > +	if (IS_ERR_OR_NULL(opp_gold)) {
> 
> same here.
> 
> > +		dev_err(cpu_dev_gold, "Failed to set supported
> hardware\n");
> > +		ret = PTR_ERR(opp_gold);
> > +		goto free_opp_silver;
> > +	}
> > +
> > +	pdev = platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
> > +	if (!IS_ERR_OR_NULL(pdev))
> > +		goto out;
> 
> Simply return from here and remove the useless label out.
> 
> > +
> > +	ret = PTR_ERR(pdev);
> > +	dev_err(cpu_dev_silver, "Failed to register platform device\n");
> > +	dev_pm_opp_put_supported_hw(opp_gold);
> > +
> > +free_opp_silver:
> > +	dev_pm_opp_put_supported_hw(opp_silver);
> > +
> > +free_np:
> > +	of_node_put(np);
> > +
> > +out:
> > +	return ret;
> > +}
> > +late_initcall(qcom_cpufreq_kryo_driver_init);
> 
> Please resend only this patch now or just paste the new code in a mail
here
> so that I can review it quickly and then you can resend the final version.
Most
> of the patches aren't changing anyway.
> 
> --
> viresh