// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2013 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 */

#include "msm_gpu.h"
#include "msm_gpu_trace.h"

#include <linux/devfreq.h>
#include <linux/devfreq_cooling.h>
#include <linux/math64.h>
#include <linux/units.h>

/*
 * Power Management:
 */

static int msm_devfreq_target(struct device *dev, unsigned long *freq,
                u32 flags)
{
        struct msm_gpu *gpu = dev_to_gpu(dev);
        struct msm_gpu_devfreq *df = &gpu->devfreq;
        struct dev_pm_opp *opp;

        /*
         * Note that devfreq_recommended_opp() can modify the freq
         * to something that actually is in the opp table:
         */
        opp = devfreq_recommended_opp(dev, freq, flags);
        if (IS_ERR(opp))
                return PTR_ERR(opp);

        trace_msm_gpu_freq_change(dev_pm_opp_get_freq(opp));

        /*
         * If the GPU is idle, devfreq is not aware, so just stash
         * the new target freq (to use when we return to active)
         */
        if (df->idle_freq) {
                df->idle_freq = *freq;
                dev_pm_opp_put(opp);
                return 0;
        }

        if (gpu->funcs->gpu_set_freq) {
                mutex_lock(&df->lock);
                gpu->funcs->gpu_set_freq(gpu, opp, df->suspended);
                mutex_unlock(&df->lock);
        } else {
                dev_pm_opp_set_rate(dev, *freq);
        }

        dev_pm_opp_put(opp);

        return 0;
}

static unsigned long get_freq(struct msm_gpu *gpu)
{
        struct msm_gpu_devfreq *df = &gpu->devfreq;

        /*
         * If the GPU is idle, use the shadow/saved freq to avoid
         * confusing devfreq (which is unaware that we are switching
         * to lowest freq until the device is active again)
         */
        if (df->idle_freq)
                return df->idle_freq;

        if (gpu->funcs->gpu_get_freq)
                return gpu->funcs->gpu_get_freq(gpu);

        return clk_get_rate(gpu->core_clk);
}

static int msm_devfreq_get_dev_status(struct device *dev,
                struct devfreq_dev_status *status)
{
        struct msm_gpu *gpu = dev_to_gpu(dev);
        struct msm_gpu_devfreq *df = &gpu->devfreq;
        u64 busy_cycles, busy_time;
        unsigned long sample_rate;
        ktime_t time;

        mutex_lock(&df->lock);

        status->current_frequency = get_freq(gpu);
        time = ktime_get();
        status->total_time = ktime_us_delta(time, df->time);
        df->time = time;

        if (df->suspended) {
                mutex_unlock(&df->lock);
                status->busy_time = 0;
                return 0;
        }

        busy_cycles = gpu->funcs->gpu_busy(gpu, &sample_rate);
        busy_time = busy_cycles - df->busy_cycles;
        df->busy_cycles = busy_cycles;

        mutex_unlock(&df->lock);

        busy_time *= USEC_PER_SEC;
        busy_time = div64_ul(busy_time, sample_rate);
        if (WARN_ON(busy_time > ~0LU))
                busy_time = ~0LU;

        status->busy_time = busy_time;

        return 0;
}

static int msm_devfreq_get_cur_freq(struct device *dev, unsigned long *freq)
{
        *freq = get_freq(dev_to_gpu(dev));

        return 0;
}

static struct devfreq_dev_profile msm_devfreq_profile = {
        .timer = DEVFREQ_TIMER_DELAYED,
        .polling_ms = 50,
        .target = msm_devfreq_target,
        .get_dev_status = msm_devfreq_get_dev_status,
        .get_cur_freq = msm_devfreq_get_cur_freq,
};

static void msm_devfreq_boost_work(struct kthread_work *work);
static void msm_devfreq_idle_work(struct kthread_work *work);

static bool has_devfreq(struct msm_gpu *gpu)
{
        struct msm_gpu_devfreq *df = &gpu->devfreq;
        return !!df->devfreq;
}

void msm_devfreq_init(struct msm_gpu *gpu)
{
        struct msm_gpu_devfreq *df = &gpu->devfreq;
        struct msm_drm_private *priv = gpu->dev->dev_private;
        int ret;

        /* We need target support to do devfreq */
        if (!gpu->funcs->gpu_busy)
                return;

        /*
         * Setup default values for simple_ondemand governor tuning.  We
         * want to throttle up at 50% load for the double-buffer case,
         * where due to stalling waiting for vblank we could get stuck
         * at (for ex) 30fps at 50% utilization.
         */
        priv->gpu_devfreq_config.upthreshold = 50;
        priv->gpu_devfreq_config.downdifferential = 10;

        mutex_init(&df->lock);
        df->suspended = true;

        ret = dev_pm_qos_add_request(&gpu->pdev->dev, &df->boost_freq,
                                     DEV_PM_QOS_MIN_FREQUENCY, 0);
        if (ret < 0) {
                DRM_DEV_ERROR(&gpu->pdev->dev, "Couldn't initialize QoS\n");
                return;
        }

        msm_devfreq_profile.initial_freq = gpu->fast_rate;

        /*
         * Don't set the freq_table or max_state and let devfreq build the table
         * from OPP
         * After a deferred probe, these may have be left to non-zero values,
         * so set them back to zero before creating the devfreq device
         */
        msm_devfreq_profile.freq_table = NULL;
        msm_devfreq_profile.max_state = 0;

        df->devfreq = devm_devfreq_add_device(&gpu->pdev->dev,
                        &msm_devfreq_profile, DEVFREQ_GOV_SIMPLE_ONDEMAND,
                        &priv->gpu_devfreq_config);

        if (IS_ERR(df->devfreq)) {
                DRM_DEV_ERROR(&gpu->pdev->dev, "Couldn't initialize GPU devfreq\n");
                dev_pm_qos_remove_request(&df->boost_freq);
                df->devfreq = NULL;
                return;
        }

        devfreq_suspend_device(df->devfreq);

        gpu->cooling = of_devfreq_cooling_register(gpu->pdev->dev.of_node, df->devfreq);
        if (IS_ERR(gpu->cooling)) {
                DRM_DEV_ERROR(&gpu->pdev->dev,
                                "Couldn't register GPU cooling device\n");
                gpu->cooling = NULL;
        }

        msm_hrtimer_work_init(&df->boost_work, gpu->worker, msm_devfreq_boost_work,
                              CLOCK_MONOTONIC, HRTIMER_MODE_REL);
        msm_hrtimer_work_init(&df->idle_work, gpu->worker, msm_devfreq_idle_work,
                              CLOCK_MONOTONIC, HRTIMER_MODE_REL);
}

static void cancel_idle_work(struct msm_gpu_devfreq *df)
{
        hrtimer_cancel(&df->idle_work.timer);
        kthread_cancel_work_sync(&df->idle_work.work);
}

static void cancel_boost_work(struct msm_gpu_devfreq *df)
{
        hrtimer_cancel(&df->boost_work.timer);
        kthread_cancel_work_sync(&df->boost_work.work);
}

void msm_devfreq_cleanup(struct msm_gpu *gpu)
{
        struct msm_gpu_devfreq *df = &gpu->devfreq;

        if (!has_devfreq(gpu))
                return;

        devfreq_cooling_unregister(gpu->cooling);
        dev_pm_qos_remove_request(&df->boost_freq);
}

void msm_devfreq_resume(struct msm_gpu *gpu)
{
        struct msm_gpu_devfreq *df = &gpu->devfreq;
        unsigned long sample_rate;

        if (!has_devfreq(gpu))
                return;

        mutex_lock(&df->lock);
        df->busy_cycles = gpu->funcs->gpu_busy(gpu, &sample_rate);
        df->time = ktime_get();
        df->suspended = false;
        mutex_unlock(&df->lock);

        devfreq_resume_device(df->devfreq);
}

void msm_devfreq_suspend(struct msm_gpu *gpu)
{
        struct msm_gpu_devfreq *df = &gpu->devfreq;

        if (!has_devfreq(gpu))
                return;

        mutex_lock(&df->lock);
        df->suspended = true;
        mutex_unlock(&df->lock);

        devfreq_suspend_device(df->devfreq);

        cancel_idle_work(df);
        cancel_boost_work(df);
}

static void msm_devfreq_boost_work(struct kthread_work *work)
{
        struct msm_gpu_devfreq *df = container_of(work,
                        struct msm_gpu_devfreq, boost_work.work);

        dev_pm_qos_update_request(&df->boost_freq, 0);
}

void msm_devfreq_boost(struct msm_gpu *gpu, unsigned factor)
{
        struct msm_gpu_devfreq *df = &gpu->devfreq;
        uint64_t freq;

        if (!has_devfreq(gpu))
                return;

        freq = get_freq(gpu);
        freq *= factor;

        /*
         * A nice little trap is that PM QoS operates in terms of KHz,
         * while devfreq operates in terms of Hz:
         */
        do_div(freq, HZ_PER_KHZ);

        dev_pm_qos_update_request(&df->boost_freq, freq);

        msm_hrtimer_queue_work(&df->boost_work,
                               ms_to_ktime(msm_devfreq_profile.polling_ms),
                               HRTIMER_MODE_REL);
}

void msm_devfreq_active(struct msm_gpu *gpu)
{
        struct msm_gpu_devfreq *df = &gpu->devfreq;
        unsigned int idle_time;
        unsigned long target_freq;

        if (!has_devfreq(gpu))
                return;

        /*
         * Cancel any pending transition to idle frequency:
         */
        cancel_idle_work(df);

        /*
         * Hold devfreq lock to synchronize with get_dev_status()/
         * target() callbacks
         */
        mutex_lock(&df->devfreq->lock);

        target_freq = df->idle_freq;

        idle_time = ktime_to_ms(ktime_sub(ktime_get(), df->idle_time));

        df->idle_freq = 0;

        /*
         * We could have become active again before the idle work had a
         * chance to run, in which case the df->idle_freq would have
         * still been zero.  In this case, no need to change freq.
         */
        if (target_freq)
                msm_devfreq_target(&gpu->pdev->dev, &target_freq, 0);

        mutex_unlock(&df->devfreq->lock);

        /*
         * If we've been idle for a significant fraction of a polling
         * interval, then we won't meet the threshold of busyness for
         * the governor to ramp up the freq.. so give some boost
         */
        if (idle_time > msm_devfreq_profile.polling_ms) {
                msm_devfreq_boost(gpu, 2);
        }
}


static void msm_devfreq_idle_work(struct kthread_work *work)
{
        struct msm_gpu_devfreq *df = container_of(work,
                        struct msm_gpu_devfreq, idle_work.work);
        struct msm_gpu *gpu = container_of(df, struct msm_gpu, devfreq);
        struct msm_drm_private *priv = gpu->dev->dev_private;
        unsigned long idle_freq, target_freq = 0;

        /*
         * Hold devfreq lock to synchronize with get_dev_status()/
         * target() callbacks
         */
        mutex_lock(&df->devfreq->lock);

        idle_freq = get_freq(gpu);

        if (priv->gpu_clamp_to_idle)
                msm_devfreq_target(&gpu->pdev->dev, &target_freq, 0);

        df->idle_time = ktime_get();
        df->idle_freq = idle_freq;

        mutex_unlock(&df->devfreq->lock);
}

void msm_devfreq_idle(struct msm_gpu *gpu)
{
        struct msm_gpu_devfreq *df = &gpu->devfreq;

        if (!has_devfreq(gpu))
                return;

        msm_hrtimer_queue_work(&df->idle_work, ms_to_ktime(1),
                               HRTIMER_MODE_REL);
}