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/devfreq_cooling.h>
   5 #include <linux/platform_device.h>
   6 #include <linux/pm_opp.h>
   7 #include <linux/clk.h>
   8 #include <linux/regulator/consumer.h>
   9
  10 #include "panfrost_device.h"
  11 #include "panfrost_devfreq.h"
  12 #include "panfrost_features.h"
  13 #include "panfrost_issues.h"
  14 #include "panfrost_gpu.h"
  15 #include "panfrost_regs.h"
  16
  17 static void panfrost_devfreq_update_utilization(struct panfrost_device *pfdev);
  18
  19 static int panfrost_devfreq_target(struct device *dev, unsigned long *freq,
  20                                    u32 flags)
  21 {
  22         struct dev_pm_opp *opp;
  23         int err;
  24
  25         opp = devfreq_recommended_opp(dev, freq, flags);
  26         if (IS_ERR(opp))
  27                 return PTR_ERR(opp);
  28         dev_pm_opp_put(opp);
  29
  30         err = dev_pm_opp_set_rate(dev, *freq);
  31         if (err)
  32                 return err;
  33
  34         return 0;
  35 }
  36
  37 static void panfrost_devfreq_reset(struct panfrost_device *pfdev)
  38 {
  39         pfdev->devfreq.busy_time = 0;
  40         pfdev->devfreq.idle_time = 0;
  41         pfdev->devfreq.time_last_update = ktime_get();
  42 }
  43
  44 static int panfrost_devfreq_get_dev_status(struct device *dev,
  45                                            struct devfreq_dev_status *status)
  46 {
  47         struct panfrost_device *pfdev = dev_get_drvdata(dev);
  48
  49         panfrost_devfreq_update_utilization(pfdev);
  50
  51         status->current_frequency = clk_get_rate(pfdev->clock);
  52         status->total_time = ktime_to_ns(ktime_add(pfdev->devfreq.busy_time,
  53                                                    pfdev->devfreq.idle_time));
  54
  55         status->busy_time = ktime_to_ns(pfdev->devfreq.busy_time);
  56
  57         panfrost_devfreq_reset(pfdev);
  58
  59         dev_dbg(pfdev->dev, "busy %lu total %lu %lu %% freq %lu MHz\n", status->busy_time,
  60                 status->total_time,
  61                 status->busy_time / (status->total_time / 100),
  62                 status->current_frequency / 1000 / 1000);
  63
  64         return 0;
  65 }
  66
  67 static struct devfreq_dev_profile panfrost_devfreq_profile = {
  68         .polling_ms = 50, /* ~3 frames */
  69         .target = panfrost_devfreq_target,
  70         .get_dev_status = panfrost_devfreq_get_dev_status,
  71 };
  72
  73 int panfrost_devfreq_init(struct panfrost_device *pfdev)
  74 {
  75         int ret;
  76         struct dev_pm_opp *opp;
  77         unsigned long cur_freq;
  78         struct device *dev = &pfdev->pdev->dev;
  79         struct devfreq *devfreq;
  80         struct thermal_cooling_device *cooling;
  81
  82         ret = dev_pm_opp_of_add_table(dev);
  83         if (ret == -ENODEV) /* Optional, continue without devfreq */
  84                 return 0;
  85         else if (ret)
  86                 return ret;
  87
  88         panfrost_devfreq_reset(pfdev);
  89
  90         cur_freq = clk_get_rate(pfdev->clock);
  91
  92         opp = devfreq_recommended_opp(dev, &cur_freq, 0);
  93         if (IS_ERR(opp))
  94                 return PTR_ERR(opp);
  95
  96         panfrost_devfreq_profile.initial_freq = cur_freq;
  97         dev_pm_opp_put(opp);
  98
  99         devfreq = devm_devfreq_add_device(dev, &panfrost_devfreq_profile,
 100                                           DEVFREQ_GOV_SIMPLE_ONDEMAND, NULL);
 101         if (IS_ERR(devfreq)) {
 102                 DRM_DEV_ERROR(dev, "Couldn't initialize GPU devfreq\n");
 103                 dev_pm_opp_of_remove_table(dev);
 104                 return PTR_ERR(devfreq);
 105         }
 106         pfdev->devfreq.devfreq = devfreq;
 107
 108         cooling = of_devfreq_cooling_register(dev->of_node, devfreq);
 109         if (IS_ERR(cooling))
 110                 DRM_DEV_INFO(dev, "Failed to register cooling device\n");
 111         else
 112                 pfdev->devfreq.cooling = cooling;
 113
 114         return 0;
 115 }
 116
 117 void panfrost_devfreq_fini(struct panfrost_device *pfdev)
 118 {
 119         if (pfdev->devfreq.cooling)
 120                 devfreq_cooling_unregister(pfdev->devfreq.cooling);
 121         dev_pm_opp_of_remove_table(&pfdev->pdev->dev);
 122 }
 123
 124 void panfrost_devfreq_resume(struct panfrost_device *pfdev)
 125 {
 126         if (!pfdev->devfreq.devfreq)
 127                 return;
 128
 129         panfrost_devfreq_reset(pfdev);
 130
 131         devfreq_resume_device(pfdev->devfreq.devfreq);
 132 }
 133
 134 void panfrost_devfreq_suspend(struct panfrost_device *pfdev)
 135 {
 136         if (!pfdev->devfreq.devfreq)
 137                 return;
 138
 139         devfreq_suspend_device(pfdev->devfreq.devfreq);
 140 }
 141
 142 static void panfrost_devfreq_update_utilization(struct panfrost_device *pfdev)
 143 {
 144         ktime_t now;
 145         ktime_t last;
 146
 147         if (!pfdev->devfreq.devfreq)
 148                 return;
 149
 150         now = ktime_get();
 151         last = pfdev->devfreq.time_last_update;
 152
 153         if (atomic_read(&pfdev->devfreq.busy_count) > 0)
 154                 pfdev->devfreq.busy_time += ktime_sub(now, last);
 155         else
 156                 pfdev->devfreq.idle_time += ktime_sub(now, last);
 157
 158         pfdev->devfreq.time_last_update = now;
 159 }
 160
 161 void panfrost_devfreq_record_busy(struct panfrost_device *pfdev)
 162 {
 163         panfrost_devfreq_update_utilization(pfdev);
 164         atomic_inc(&pfdev->devfreq.busy_count);
 165 }
 166
 167 void panfrost_devfreq_record_idle(struct panfrost_device *pfdev)
 168 {
 169         int count;
 170
 171         panfrost_devfreq_update_utilization(pfdev);
 172         count = atomic_dec_if_positive(&pfdev->devfreq.busy_count);
 173         WARN_ON(count < 0);
 174 }