drivers/gpu/drm/panfrost/panfrost_devfreq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright 2019 Collabora ltd. */
   3
   4 #include <linux/clk.h>
   5 #include <linux/devfreq.h>
   6 #include <linux/devfreq_cooling.h>
   7 #include <linux/nvmem-consumer.h>
   8 #include <linux/platform_device.h>
   9 #include <linux/pm_opp.h>
  10
  11 #include "panfrost_device.h"
  12 #include "panfrost_devfreq.h"
  13
  14 static void panfrost_devfreq_update_utilization(struct panfrost_devfreq *pfdevfreq)
  15 {
  16         ktime_t now, last;
  17
  18         now = ktime_get();
  19         last = pfdevfreq->time_last_update;
  20
  21         if (pfdevfreq->busy_count > 0)
  22                 pfdevfreq->busy_time += ktime_sub(now, last);
  23         else
  24                 pfdevfreq->idle_time += ktime_sub(now, last);
  25
  26         pfdevfreq->time_last_update = now;
  27 }
  28
  29 static int panfrost_devfreq_target(struct device *dev, unsigned long *freq,
  30                                    u32 flags)
  31 {
  32         struct dev_pm_opp *opp;
  33
  34         opp = devfreq_recommended_opp(dev, freq, flags);
  35         if (IS_ERR(opp))
  36                 return PTR_ERR(opp);
  37         dev_pm_opp_put(opp);
  38
  39         return dev_pm_opp_set_rate(dev, *freq);
  40 }
  41
  42 static void panfrost_devfreq_reset(struct panfrost_devfreq *pfdevfreq)
  43 {
  44         pfdevfreq->busy_time = 0;
  45         pfdevfreq->idle_time = 0;
  46         pfdevfreq->time_last_update = ktime_get();
  47 }
  48
  49 static int panfrost_devfreq_get_dev_status(struct device *dev,
  50                                            struct devfreq_dev_status *status)
  51 {
  52         struct panfrost_device *pfdev = dev_get_drvdata(dev);
  53         struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
  54         unsigned long irqflags;
  55
  56         status->current_frequency = clk_get_rate(pfdev->clock);
  57
  58         spin_lock_irqsave(&pfdevfreq->lock, irqflags);
  59
  60         panfrost_devfreq_update_utilization(pfdevfreq);
  61
  62         status->total_time = ktime_to_ns(ktime_add(pfdevfreq->busy_time,
  63                                                    pfdevfreq->idle_time));
  64
  65         status->busy_time = ktime_to_ns(pfdevfreq->busy_time);
  66
  67         panfrost_devfreq_reset(pfdevfreq);
  68
  69         spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
  70
  71         dev_dbg(pfdev->dev, "busy %lu total %lu %lu %% freq %lu MHz\n",
  72                 status->busy_time, status->total_time,
  73                 status->busy_time / (status->total_time / 100),
  74                 status->current_frequency / 1000 / 1000);
  75
  76         return 0;
  77 }
  78
  79 static struct devfreq_dev_profile panfrost_devfreq_profile = {
  80         .timer = DEVFREQ_TIMER_DELAYED,
  81         .polling_ms = 50, /* ~3 frames */
  82         .target = panfrost_devfreq_target,
  83         .get_dev_status = panfrost_devfreq_get_dev_status,
  84 };
  85
  86 static int panfrost_read_speedbin(struct device *dev)
  87 {
  88         u32 val;
  89         int ret;
  90
  91         ret = nvmem_cell_read_variable_le_u32(dev, "speed-bin", &val);
  92         if (ret) {
  93                 /*
  94                  * -ENOENT means that this platform doesn't support speedbins
  95                  * as it didn't declare any speed-bin nvmem: in this case, we
  96                  * keep going without it; any other error means that we are
  97                  * supposed to read the bin value, but we failed doing so.
  98                  */
  99                 if (ret != -ENOENT) {
 100                         DRM_DEV_ERROR(dev, "Cannot read speed-bin (%d).", ret);
 101                         return ret;
 102                 }
 103
 104                 return 0;
 105         }
 106         DRM_DEV_DEBUG(dev, "Using speed-bin = 0x%x\n", val);
 107
 108         return devm_pm_opp_set_supported_hw(dev, &val, 1);
 109 }
 110
 111 int panfrost_devfreq_init(struct panfrost_device *pfdev)
 112 {
 113         int ret;
 114         struct dev_pm_opp *opp;
 115         unsigned long cur_freq;
 116         struct device *dev = &pfdev->pdev->dev;
 117         struct devfreq *devfreq;
 118         struct thermal_cooling_device *cooling;
 119         struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
 120
 121         if (pfdev->comp->num_supplies > 1) {
 122                 /*
 123                  * GPUs with more than 1 supply require platform-specific handling:
 124                  * continue without devfreq
 125                  */
 126                 DRM_DEV_INFO(dev, "More than 1 supply is not supported yet\n");
 127                 return 0;
 128         }
 129
 130         ret = panfrost_read_speedbin(dev);
 131         if (ret)
 132                 return ret;
 133
 134         ret = devm_pm_opp_set_regulators(dev, pfdev->comp->supply_names);
 135         if (ret) {
 136                 /* Continue if the optional regulator is missing */
 137                 if (ret != -ENODEV) {
 138                         if (ret != -EPROBE_DEFER)
 139                                 DRM_DEV_ERROR(dev, "Couldn't set OPP regulators\n");
 140                         return ret;
 141                 }
 142         }
 143
 144         ret = devm_pm_opp_of_add_table(dev);
 145         if (ret) {
 146                 /* Optional, continue without devfreq */
 147                 if (ret == -ENODEV)
 148                         ret = 0;
 149                 return ret;
 150         }
 151         pfdevfreq->opp_of_table_added = true;
 152
 153         spin_lock_init(&pfdevfreq->lock);
 154
 155         panfrost_devfreq_reset(pfdevfreq);
 156
 157         cur_freq = clk_get_rate(pfdev->clock);
 158
 159         opp = devfreq_recommended_opp(dev, &cur_freq, 0);
 160         if (IS_ERR(opp))
 161                 return PTR_ERR(opp);
 162
 163         panfrost_devfreq_profile.initial_freq = cur_freq;
 164
 165         /*
 166          * Set the recommend OPP this will enable and configure the regulator
 167          * if any and will avoid a switch off by regulator_late_cleanup()
 168          */
 169         ret = dev_pm_opp_set_opp(dev, opp);
 170         if (ret) {
 171                 DRM_DEV_ERROR(dev, "Couldn't set recommended OPP\n");
 172                 return ret;
 173         }
 174
 175         dev_pm_opp_put(opp);
 176
 177         /*
 178          * Setup default thresholds for the simple_ondemand governor.
 179          * The values are chosen based on experiments.
 180          */
 181         pfdevfreq->gov_data.upthreshold = 45;
 182         pfdevfreq->gov_data.downdifferential = 5;
 183
 184         devfreq = devm_devfreq_add_device(dev, &panfrost_devfreq_profile,
 185                                           DEVFREQ_GOV_SIMPLE_ONDEMAND,
 186                                           &pfdevfreq->gov_data);
 187         if (IS_ERR(devfreq)) {
 188                 DRM_DEV_ERROR(dev, "Couldn't initialize GPU devfreq\n");
 189                 return PTR_ERR(devfreq);
 190         }
 191         pfdevfreq->devfreq = devfreq;
 192
 193         cooling = devfreq_cooling_em_register(devfreq, NULL);
 194         if (IS_ERR(cooling))
 195                 DRM_DEV_INFO(dev, "Failed to register cooling device\n");
 196         else
 197                 pfdevfreq->cooling = cooling;
 198
 199         return 0;
 200 }
 201
 202 void panfrost_devfreq_fini(struct panfrost_device *pfdev)
 203 {
 204         struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
 205
 206         if (pfdevfreq->cooling) {
 207                 devfreq_cooling_unregister(pfdevfreq->cooling);
 208                 pfdevfreq->cooling = NULL;
 209         }
 210 }
 211
 212 void panfrost_devfreq_resume(struct panfrost_device *pfdev)
 213 {
 214         struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
 215
 216         if (!pfdevfreq->devfreq)
 217                 return;
 218
 219         panfrost_devfreq_reset(pfdevfreq);
 220
 221         devfreq_resume_device(pfdevfreq->devfreq);
 222 }
 223
 224 void panfrost_devfreq_suspend(struct panfrost_device *pfdev)
 225 {
 226         struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
 227
 228         if (!pfdevfreq->devfreq)
 229                 return;
 230
 231         devfreq_suspend_device(pfdevfreq->devfreq);
 232 }
 233
 234 void panfrost_devfreq_record_busy(struct panfrost_devfreq *pfdevfreq)
 235 {
 236         unsigned long irqflags;
 237
 238         if (!pfdevfreq->devfreq)
 239                 return;
 240
 241         spin_lock_irqsave(&pfdevfreq->lock, irqflags);
 242
 243         panfrost_devfreq_update_utilization(pfdevfreq);
 244
 245         pfdevfreq->busy_count++;
 246
 247         spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
 248 }
 249
 250 void panfrost_devfreq_record_idle(struct panfrost_devfreq *pfdevfreq)
 251 {
 252         unsigned long irqflags;
 253
 254         if (!pfdevfreq->devfreq)
 255                 return;
 256
 257         spin_lock_irqsave(&pfdevfreq->lock, irqflags);
 258
 259         panfrost_devfreq_update_utilization(pfdevfreq);
 260
 261         WARN_ON(--pfdevfreq->busy_count < 0);
 262
 263         spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
 264 }