// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2011-2014, The Linux Foundation. All rights reserved.
 * Copyright (c) 2014,2015, Linaro Ltd.
 *
 * SAW power controller driver
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/cpuidle.h>
#include <linux/cpu_pm.h>
#include <linux/firmware/qcom/qcom_scm.h>
#include <soc/qcom/spm.h>

#include <asm/proc-fns.h>
#include <asm/suspend.h>

#include "dt_idle_states.h"

struct cpuidle_qcom_spm_data {
        struct cpuidle_driver cpuidle_driver;
        struct spm_driver_data *spm;
};

static int qcom_pm_collapse(unsigned long int unused)
{
        qcom_scm_cpu_power_down(QCOM_SCM_CPU_PWR_DOWN_L2_ON);

        /*
         * Returns here only if there was a pending interrupt and we did not
         * power down as a result.
         */
        return -1;
}

static int qcom_cpu_spc(struct spm_driver_data *drv)
{
        int ret;

        spm_set_low_power_mode(drv, PM_SLEEP_MODE_SPC);
        ret = cpu_suspend(0, qcom_pm_collapse);
        /*
         * ARM common code executes WFI without calling into our driver and
         * if the SPM mode is not reset, then we may accidentally power down the
         * cpu when we intended only to gate the cpu clock.
         * Ensure the state is set to standby before returning.
         */
        spm_set_low_power_mode(drv, PM_SLEEP_MODE_STBY);

        return ret;
}

static __cpuidle int spm_enter_idle_state(struct cpuidle_device *dev,
                                          struct cpuidle_driver *drv, int idx)
{
        struct cpuidle_qcom_spm_data *data = container_of(drv, struct cpuidle_qcom_spm_data,
                                                          cpuidle_driver);

        return CPU_PM_CPU_IDLE_ENTER_PARAM(qcom_cpu_spc, idx, data->spm);
}

static struct cpuidle_driver qcom_spm_idle_driver = {
        .name = "qcom_spm",
        .owner = THIS_MODULE,
        .states[0] = {
                .enter                  = spm_enter_idle_state,
                .exit_latency           = 1,
                .target_residency       = 1,
                .power_usage            = UINT_MAX,
                .name                   = "WFI",
                .desc                   = "ARM WFI",
        }
};

static const struct of_device_id qcom_idle_state_match[] = {
        { .compatible = "qcom,idle-state-spc", .data = spm_enter_idle_state },
        { },
};

static int spm_cpuidle_register(struct device *cpuidle_dev, int cpu)
{
        struct platform_device *pdev;
        struct device_node *cpu_node, *saw_node;
        struct cpuidle_qcom_spm_data *data;
        int ret;

        cpu_node = of_cpu_device_node_get(cpu);
        if (!cpu_node)
                return -ENODEV;

        saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0);
        of_node_put(cpu_node);
        if (!saw_node)
                return -ENODEV;

        pdev = of_find_device_by_node(saw_node);
        of_node_put(saw_node);
        if (!pdev)
                return -ENODEV;

        data = devm_kzalloc(cpuidle_dev, sizeof(*data), GFP_KERNEL);
        if (!data) {
                put_device(&pdev->dev);
                return -ENOMEM;
        }

        data->spm = dev_get_drvdata(&pdev->dev);
        put_device(&pdev->dev);
        if (!data->spm)
                return -EINVAL;

        data->cpuidle_driver = qcom_spm_idle_driver;
        data->cpuidle_driver.cpumask = (struct cpumask *)cpumask_of(cpu);

        ret = dt_init_idle_driver(&data->cpuidle_driver,
                                  qcom_idle_state_match, 1);
        if (ret <= 0)
                return ret ? : -ENODEV;

        return cpuidle_register(&data->cpuidle_driver, NULL);
}

static int spm_cpuidle_drv_probe(struct platform_device *pdev)
{
        int cpu, ret;

        if (!qcom_scm_is_available())
                return -EPROBE_DEFER;

        ret = qcom_scm_set_warm_boot_addr(cpu_resume_arm);
        if (ret)
                return dev_err_probe(&pdev->dev, ret, "set warm boot addr failed");

        for_each_present_cpu(cpu) {
                ret = spm_cpuidle_register(&pdev->dev, cpu);
                if (ret && ret != -ENODEV) {
                        dev_err(&pdev->dev,
                                "Cannot register for CPU%d: %d\n", cpu, ret);
                }
        }

        return 0;
}

static struct platform_driver spm_cpuidle_driver = {
        .probe = spm_cpuidle_drv_probe,
        .driver = {
                .name = "qcom-spm-cpuidle",
                .suppress_bind_attrs = true,
        },
};

static bool __init qcom_spm_find_any_cpu(void)
{
        struct device_node *cpu_node, *saw_node;

        for_each_of_cpu_node(cpu_node) {
                saw_node = of_parse_phandle(cpu_node, "qcom,saw", 0);
                if (of_device_is_available(saw_node)) {
                        of_node_put(saw_node);
                        of_node_put(cpu_node);
                        return true;
                }
                of_node_put(saw_node);
        }
        return false;
}

static int __init qcom_spm_cpuidle_init(void)
{
        struct platform_device *pdev;
        int ret;

        ret = platform_driver_register(&spm_cpuidle_driver);
        if (ret)
                return ret;

        /* Make sure there is actually any CPU managed by the SPM */
        if (!qcom_spm_find_any_cpu())
                return 0;

        pdev = platform_device_register_simple("qcom-spm-cpuidle",
                                               -1, NULL, 0);
        if (IS_ERR(pdev)) {
                platform_driver_unregister(&spm_cpuidle_driver);
                return PTR_ERR(pdev);
        }

        return 0;
}
device_initcall(qcom_spm_cpuidle_init);