drivers/gpu/drm/panfrost/panfrost_devfreq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright 2019 Collabora ltd. */
   3 #include <linux/devfreq.h>
   4 #include <linux/platform_device.h>
   5 #include <linux/pm_opp.h>
   6 #include <linux/clk.h>
   7 #include <linux/regulator/consumer.h>
   8
   9 #include "panfrost_device.h"
  10 #include "panfrost_devfreq.h"
  11 #include "panfrost_features.h"
  12 #include "panfrost_issues.h"
  13 #include "panfrost_gpu.h"
  14 #include "panfrost_regs.h"
  15
  16 static void panfrost_devfreq_update_utilization(struct panfrost_device *pfdev);
  17
  18 static int panfrost_devfreq_target(struct device *dev, unsigned long *freq,
  19                                    u32 flags)
  20 {
  21         struct dev_pm_opp *opp;
  22         int err;
  23
  24         opp = devfreq_recommended_opp(dev, freq, flags);
  25         if (IS_ERR(opp))
  26                 return PTR_ERR(opp);
  27         dev_pm_opp_put(opp);
  28
  29         err = dev_pm_opp_set_rate(dev, *freq);
  30         if (err)
  31                 return err;
  32
  33         return 0;
  34 }
  35
  36 static void panfrost_devfreq_reset(struct panfrost_device *pfdev)
  37 {
  38         pfdev->devfreq.busy_time = 0;
  39         pfdev->devfreq.idle_time = 0;
  40         pfdev->devfreq.time_last_update = ktime_get();
  41 }
  42
  43 static int panfrost_devfreq_get_dev_status(struct device *dev,
  44                                            struct devfreq_dev_status *status)
  45 {
  46         struct panfrost_device *pfdev = dev_get_drvdata(dev);
  47
  48         panfrost_devfreq_update_utilization(pfdev);
  49
  50         status->current_frequency = clk_get_rate(pfdev->clock);
  51         status->total_time = ktime_to_ns(ktime_add(pfdev->devfreq.busy_time,
  52                                                    pfdev->devfreq.idle_time));
  53
  54         status->busy_time = ktime_to_ns(pfdev->devfreq.busy_time);
  55
  56         panfrost_devfreq_reset(pfdev);
  57
  58         dev_dbg(pfdev->dev, "busy %lu total %lu %lu %% freq %lu MHz\n", status->busy_time,
  59                 status->total_time,
  60                 status->busy_time / (status->total_time / 100),
  61                 status->current_frequency / 1000 / 1000);
  62
  63         return 0;
  64 }
  65
  66 static struct devfreq_dev_profile panfrost_devfreq_profile = {
  67         .polling_ms = 50, /* ~3 frames */
  68         .target = panfrost_devfreq_target,
  69         .get_dev_status = panfrost_devfreq_get_dev_status,
  70 };
  71
  72 int panfrost_devfreq_init(struct panfrost_device *pfdev)
  73 {
  74         int ret;
  75         struct dev_pm_opp *opp;
  76         unsigned long cur_freq;
  77
  78         ret = dev_pm_opp_of_add_table(&pfdev->pdev->dev);
  79         if (ret == -ENODEV) /* Optional, continue without devfreq */
  80                 return 0;
  81         else if (ret)
  82                 return ret;
  83
  84         panfrost_devfreq_reset(pfdev);
  85
  86         cur_freq = clk_get_rate(pfdev->clock);
  87
  88         opp = devfreq_recommended_opp(&pfdev->pdev->dev, &cur_freq, 0);
  89         if (IS_ERR(opp))
  90                 return PTR_ERR(opp);
  91
  92         panfrost_devfreq_profile.initial_freq = cur_freq;
  93         dev_pm_opp_put(opp);
  94
  95         pfdev->devfreq.devfreq = devm_devfreq_add_device(&pfdev->pdev->dev,
  96                         &panfrost_devfreq_profile, DEVFREQ_GOV_SIMPLE_ONDEMAND,
  97                         NULL);
  98         if (IS_ERR(pfdev->devfreq.devfreq)) {
  99                 DRM_DEV_ERROR(&pfdev->pdev->dev, "Couldn't initialize GPU devfreq\n");
 100                 ret = PTR_ERR(pfdev->devfreq.devfreq);
 101                 pfdev->devfreq.devfreq = NULL;
 102                 dev_pm_opp_of_remove_table(&pfdev->pdev->dev);
 103                 return ret;
 104         }
 105
 106         return 0;
 107 }
 108
 109 void panfrost_devfreq_fini(struct panfrost_device *pfdev)
 110 {
 111         dev_pm_opp_of_remove_table(&pfdev->pdev->dev);
 112 }
 113
 114 void panfrost_devfreq_resume(struct panfrost_device *pfdev)
 115 {
 116         if (!pfdev->devfreq.devfreq)
 117                 return;
 118
 119         panfrost_devfreq_reset(pfdev);
 120
 121         devfreq_resume_device(pfdev->devfreq.devfreq);
 122 }
 123
 124 void panfrost_devfreq_suspend(struct panfrost_device *pfdev)
 125 {
 126         if (!pfdev->devfreq.devfreq)
 127                 return;
 128
 129         devfreq_suspend_device(pfdev->devfreq.devfreq);
 130 }
 131
 132 static void panfrost_devfreq_update_utilization(struct panfrost_device *pfdev)
 133 {
 134         ktime_t now;
 135         ktime_t last;
 136
 137         if (!pfdev->devfreq.devfreq)
 138                 return;
 139
 140         now = ktime_get();
 141         last = pfdev->devfreq.time_last_update;
 142
 143         if (atomic_read(&pfdev->devfreq.busy_count) > 0)
 144                 pfdev->devfreq.busy_time += ktime_sub(now, last);
 145         else
 146                 pfdev->devfreq.idle_time += ktime_sub(now, last);
 147
 148         pfdev->devfreq.time_last_update = now;
 149 }
 150
 151 void panfrost_devfreq_record_busy(struct panfrost_device *pfdev)
 152 {
 153         panfrost_devfreq_update_utilization(pfdev);
 154         atomic_inc(&pfdev->devfreq.busy_count);
 155 }
 156
 157 void panfrost_devfreq_record_idle(struct panfrost_device *pfdev)
 158 {
 159         int count;
 160
 161         panfrost_devfreq_update_utilization(pfdev);
 162         count = atomic_dec_if_positive(&pfdev->devfreq.busy_count);
 163         WARN_ON(count < 0);
 164 }