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, int slot);
  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         ktime_t now = ktime_get();
  36         int i;
  37
  38         for (i = 0; i < NUM_JOB_SLOTS; i++) {
  39                 pfdev->devfreq.slot[i].busy_time = 0;
  40                 pfdev->devfreq.slot[i].idle_time = 0;
  41                 pfdev->devfreq.slot[i].time_last_update = now;
  42         }
  43 }
  44
  45 static int panfrost_devfreq_get_dev_status(struct device *dev,
  46                                            struct devfreq_dev_status *status)
  47 {
  48         struct panfrost_device *pfdev = dev_get_drvdata(dev);
  49         int i;
  50
  51         for (i = 0; i < NUM_JOB_SLOTS; i++) {
  52                 panfrost_devfreq_update_utilization(pfdev, i);
  53         }
  54
  55         status->current_frequency = clk_get_rate(pfdev->clock);
  56         status->total_time = ktime_to_ns(ktime_add(pfdev->devfreq.slot[0].busy_time,
  57                                                    pfdev->devfreq.slot[0].idle_time));
  58
  59         status->busy_time = 0;
  60         for (i = 0; i < NUM_JOB_SLOTS; i++) {
  61                 status->busy_time += ktime_to_ns(pfdev->devfreq.slot[i].busy_time);
  62         }
  63
  64         /* We're scheduling only to one core atm, so don't divide for now */
  65         /* status->busy_time /= NUM_JOB_SLOTS; */
  66
  67         panfrost_devfreq_reset(pfdev);
  68
  69         dev_dbg(pfdev->dev, "busy %lu total %lu %lu %% freq %lu MHz\n", status->busy_time,
  70                 status->total_time,
  71                 status->busy_time / (status->total_time / 100),
  72                 status->current_frequency / 1000 / 1000);
  73
  74         return 0;
  75 }
  76
  77 static int panfrost_devfreq_get_cur_freq(struct device *dev, unsigned long *freq)
  78 {
  79         struct panfrost_device *pfdev = platform_get_drvdata(to_platform_device(dev));
  80
  81         *freq = clk_get_rate(pfdev->clock);
  82
  83         return 0;
  84 }
  85
  86 static struct devfreq_dev_profile panfrost_devfreq_profile = {
  87         .polling_ms = 50, /* ~3 frames */
  88         .target = panfrost_devfreq_target,
  89         .get_dev_status = panfrost_devfreq_get_dev_status,
  90         .get_cur_freq = panfrost_devfreq_get_cur_freq,
  91 };
  92
  93 int panfrost_devfreq_init(struct panfrost_device *pfdev)
  94 {
  95         int ret;
  96         struct dev_pm_opp *opp;
  97         unsigned long cur_freq;
  98
  99         ret = dev_pm_opp_of_add_table(&pfdev->pdev->dev);
 100         if (ret == -ENODEV) /* Optional, continue without devfreq */
 101                 return 0;
 102         else if (ret)
 103                 return ret;
 104
 105         panfrost_devfreq_reset(pfdev);
 106
 107         cur_freq = clk_get_rate(pfdev->clock);
 108
 109         opp = devfreq_recommended_opp(&pfdev->pdev->dev, &cur_freq, 0);
 110         if (IS_ERR(opp))
 111                 return PTR_ERR(opp);
 112
 113         panfrost_devfreq_profile.initial_freq = cur_freq;
 114         dev_pm_opp_put(opp);
 115
 116         pfdev->devfreq.devfreq = devm_devfreq_add_device(&pfdev->pdev->dev,
 117                         &panfrost_devfreq_profile, DEVFREQ_GOV_SIMPLE_ONDEMAND,
 118                         NULL);
 119         if (IS_ERR(pfdev->devfreq.devfreq)) {
 120                 DRM_DEV_ERROR(&pfdev->pdev->dev, "Couldn't initialize GPU devfreq\n");
 121                 ret = PTR_ERR(pfdev->devfreq.devfreq);
 122                 pfdev->devfreq.devfreq = NULL;
 123                 dev_pm_opp_of_remove_table(&pfdev->pdev->dev);
 124                 return ret;
 125         }
 126
 127         return 0;
 128 }
 129
 130 void panfrost_devfreq_fini(struct panfrost_device *pfdev)
 131 {
 132         dev_pm_opp_of_remove_table(&pfdev->pdev->dev);
 133 }
 134
 135 void panfrost_devfreq_resume(struct panfrost_device *pfdev)
 136 {
 137         int i;
 138
 139         if (!pfdev->devfreq.devfreq)
 140                 return;
 141
 142         panfrost_devfreq_reset(pfdev);
 143         for (i = 0; i < NUM_JOB_SLOTS; i++)
 144                 pfdev->devfreq.slot[i].busy = false;
 145
 146         devfreq_resume_device(pfdev->devfreq.devfreq);
 147 }
 148
 149 void panfrost_devfreq_suspend(struct panfrost_device *pfdev)
 150 {
 151         if (!pfdev->devfreq.devfreq)
 152                 return;
 153
 154         devfreq_suspend_device(pfdev->devfreq.devfreq);
 155 }
 156
 157 static void panfrost_devfreq_update_utilization(struct panfrost_device *pfdev, int slot)
 158 {
 159         struct panfrost_devfreq_slot *devfreq_slot = &pfdev->devfreq.slot[slot];
 160         ktime_t now;
 161         ktime_t last;
 162
 163         if (!pfdev->devfreq.devfreq)
 164                 return;
 165
 166         now = ktime_get();
 167         last = pfdev->devfreq.slot[slot].time_last_update;
 168
 169         /* If we last recorded a transition to busy, we have been idle since */
 170         if (devfreq_slot->busy)
 171                 pfdev->devfreq.slot[slot].busy_time += ktime_sub(now, last);
 172         else
 173                 pfdev->devfreq.slot[slot].idle_time += ktime_sub(now, last);
 174
 175         pfdev->devfreq.slot[slot].time_last_update = now;
 176 }
 177
 178 /* The job scheduler is expected to call this at every transition busy <-> idle */
 179 void panfrost_devfreq_record_transition(struct panfrost_device *pfdev, int slot)
 180 {
 181         struct panfrost_devfreq_slot *devfreq_slot = &pfdev->devfreq.slot[slot];
 182
 183         panfrost_devfreq_update_utilization(pfdev, slot);
 184         devfreq_slot->busy = !devfreq_slot->busy;
 185 }