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