drivers/gpu/drm/msm/msm_gpu_devfreq.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2013 Red Hat
   4  * Author: Rob Clark <[email protected]>
   5  */
   6
   7 #include "msm_gpu.h"
   8 #include "msm_gpu_trace.h"
   9
  10 #include <linux/devfreq.h>
  11 #include <linux/devfreq_cooling.h>
  12 #include <linux/math64.h>
  13 #include <linux/units.h>
  14
  15 /*
  16  * Power Management:
  17  */
  18
  19 static int msm_devfreq_target(struct device *dev, unsigned long *freq,
  20                 u32 flags)
  21 {
  22         struct msm_gpu *gpu = dev_to_gpu(dev);
  23         struct msm_gpu_devfreq *df = &gpu->devfreq;
  24         struct dev_pm_opp *opp;
  25
  26         /*
  27          * Note that devfreq_recommended_opp() can modify the freq
  28          * to something that actually is in the opp table:
  29          */
  30         opp = devfreq_recommended_opp(dev, freq, flags);
  31         if (IS_ERR(opp))
  32                 return PTR_ERR(opp);
  33
  34         trace_msm_gpu_freq_change(dev_pm_opp_get_freq(opp));
  35
  36         /*
  37          * If the GPU is idle, devfreq is not aware, so just stash
  38          * the new target freq (to use when we return to active)
  39          */
  40         if (df->idle_freq) {
  41                 df->idle_freq = *freq;
  42                 dev_pm_opp_put(opp);
  43                 return 0;
  44         }
  45
  46         if (gpu->funcs->gpu_set_freq) {
  47                 mutex_lock(&df->lock);
  48                 gpu->funcs->gpu_set_freq(gpu, opp, df->suspended);
  49                 mutex_unlock(&df->lock);
  50         } else {
  51                 dev_pm_opp_set_rate(dev, *freq);
  52         }
  53
  54         dev_pm_opp_put(opp);
  55
  56         return 0;
  57 }
  58
  59 static unsigned long get_freq(struct msm_gpu *gpu)
  60 {
  61         struct msm_gpu_devfreq *df = &gpu->devfreq;
  62
  63         /*
  64          * If the GPU is idle, use the shadow/saved freq to avoid
  65          * confusing devfreq (which is unaware that we are switching
  66          * to lowest freq until the device is active again)
  67          */
  68         if (df->idle_freq)
  69                 return df->idle_freq;
  70
  71         if (gpu->funcs->gpu_get_freq)
  72                 return gpu->funcs->gpu_get_freq(gpu);
  73
  74         return clk_get_rate(gpu->core_clk);
  75 }
  76
  77 static int msm_devfreq_get_dev_status(struct device *dev,
  78                 struct devfreq_dev_status *status)
  79 {
  80         struct msm_gpu *gpu = dev_to_gpu(dev);
  81         struct msm_gpu_devfreq *df = &gpu->devfreq;
  82         u64 busy_cycles, busy_time;
  83         unsigned long sample_rate;
  84         ktime_t time;
  85
  86         mutex_lock(&df->lock);
  87
  88         status->current_frequency = get_freq(gpu);
  89         time = ktime_get();
  90         status->total_time = ktime_us_delta(time, df->time);
  91         df->time = time;
  92
  93         if (df->suspended) {
  94                 mutex_unlock(&df->lock);
  95                 status->busy_time = 0;
  96                 return 0;
  97         }
  98
  99         busy_cycles = gpu->funcs->gpu_busy(gpu, &sample_rate);
 100         busy_time = busy_cycles - df->busy_cycles;
 101         df->busy_cycles = busy_cycles;
 102
 103         mutex_unlock(&df->lock);
 104
 105         busy_time *= USEC_PER_SEC;
 106         busy_time = div64_ul(busy_time, sample_rate);
 107         if (WARN_ON(busy_time > ~0LU))
 108                 busy_time = ~0LU;
 109
 110         status->busy_time = busy_time;
 111
 112         return 0;
 113 }
 114
 115 static int msm_devfreq_get_cur_freq(struct device *dev, unsigned long *freq)
 116 {
 117         *freq = get_freq(dev_to_gpu(dev));
 118
 119         return 0;
 120 }
 121
 122 static struct devfreq_dev_profile msm_devfreq_profile = {
 123         .timer = DEVFREQ_TIMER_DELAYED,
 124         .polling_ms = 50,
 125         .target = msm_devfreq_target,
 126         .get_dev_status = msm_devfreq_get_dev_status,
 127         .get_cur_freq = msm_devfreq_get_cur_freq,
 128 };
 129
 130 static void msm_devfreq_boost_work(struct kthread_work *work);
 131 static void msm_devfreq_idle_work(struct kthread_work *work);
 132
 133 static bool has_devfreq(struct msm_gpu *gpu)
 134 {
 135         struct msm_gpu_devfreq *df = &gpu->devfreq;
 136         return !!df->devfreq;
 137 }
 138
 139 void msm_devfreq_init(struct msm_gpu *gpu)
 140 {
 141         struct msm_gpu_devfreq *df = &gpu->devfreq;
 142         struct msm_drm_private *priv = gpu->dev->dev_private;
 143
 144         /* We need target support to do devfreq */
 145         if (!gpu->funcs->gpu_busy)
 146                 return;
 147
 148         /*
 149          * Setup default values for simple_ondemand governor tuning.  We
 150          * want to throttle up at 50% load for the double-buffer case,
 151          * where due to stalling waiting for vblank we could get stuck
 152          * at (for ex) 30fps at 50% utilization.
 153          */
 154         priv->gpu_devfreq_config.upthreshold = 50;
 155         priv->gpu_devfreq_config.downdifferential = 10;
 156
 157         mutex_init(&df->lock);
 158
 159         dev_pm_qos_add_request(&gpu->pdev->dev, &df->boost_freq,
 160                                DEV_PM_QOS_MIN_FREQUENCY, 0);
 161
 162         msm_devfreq_profile.initial_freq = gpu->fast_rate;
 163
 164         /*
 165          * Don't set the freq_table or max_state and let devfreq build the table
 166          * from OPP
 167          * After a deferred probe, these may have be left to non-zero values,
 168          * so set them back to zero before creating the devfreq device
 169          */
 170         msm_devfreq_profile.freq_table = NULL;
 171         msm_devfreq_profile.max_state = 0;
 172
 173         df->devfreq = devm_devfreq_add_device(&gpu->pdev->dev,
 174                         &msm_devfreq_profile, DEVFREQ_GOV_SIMPLE_ONDEMAND,
 175                         &priv->gpu_devfreq_config);
 176
 177         if (IS_ERR(df->devfreq)) {
 178                 DRM_DEV_ERROR(&gpu->pdev->dev, "Couldn't initialize GPU devfreq\n");
 179                 dev_pm_qos_remove_request(&df->boost_freq);
 180                 df->devfreq = NULL;
 181                 return;
 182         }
 183
 184         devfreq_suspend_device(df->devfreq);
 185
 186         gpu->cooling = of_devfreq_cooling_register(gpu->pdev->dev.of_node, df->devfreq);
 187         if (IS_ERR(gpu->cooling)) {
 188                 DRM_DEV_ERROR(&gpu->pdev->dev,
 189                                 "Couldn't register GPU cooling device\n");
 190                 gpu->cooling = NULL;
 191         }
 192
 193         msm_hrtimer_work_init(&df->boost_work, gpu->worker, msm_devfreq_boost_work,
 194                               CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 195         msm_hrtimer_work_init(&df->idle_work, gpu->worker, msm_devfreq_idle_work,
 196                               CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 197 }
 198
 199 static void cancel_idle_work(struct msm_gpu_devfreq *df)
 200 {
 201         hrtimer_cancel(&df->idle_work.timer);
 202         kthread_cancel_work_sync(&df->idle_work.work);
 203 }
 204
 205 static void cancel_boost_work(struct msm_gpu_devfreq *df)
 206 {
 207         hrtimer_cancel(&df->boost_work.timer);
 208         kthread_cancel_work_sync(&df->boost_work.work);
 209 }
 210
 211 void msm_devfreq_cleanup(struct msm_gpu *gpu)
 212 {
 213         struct msm_gpu_devfreq *df = &gpu->devfreq;
 214
 215         if (!has_devfreq(gpu))
 216                 return;
 217
 218         devfreq_cooling_unregister(gpu->cooling);
 219         dev_pm_qos_remove_request(&df->boost_freq);
 220 }
 221
 222 void msm_devfreq_resume(struct msm_gpu *gpu)
 223 {
 224         struct msm_gpu_devfreq *df = &gpu->devfreq;
 225         unsigned long sample_rate;
 226
 227         if (!has_devfreq(gpu))
 228                 return;
 229
 230         mutex_lock(&df->lock);
 231         df->busy_cycles = gpu->funcs->gpu_busy(gpu, &sample_rate);
 232         df->time = ktime_get();
 233         df->suspended = false;
 234         mutex_unlock(&df->lock);
 235
 236         devfreq_resume_device(df->devfreq);
 237 }
 238
 239 void msm_devfreq_suspend(struct msm_gpu *gpu)
 240 {
 241         struct msm_gpu_devfreq *df = &gpu->devfreq;
 242
 243         if (!has_devfreq(gpu))
 244                 return;
 245
 246         mutex_lock(&df->lock);
 247         df->suspended = true;
 248         mutex_unlock(&df->lock);
 249
 250         devfreq_suspend_device(df->devfreq);
 251
 252         cancel_idle_work(df);
 253         cancel_boost_work(df);
 254 }
 255
 256 static void msm_devfreq_boost_work(struct kthread_work *work)
 257 {
 258         struct msm_gpu_devfreq *df = container_of(work,
 259                         struct msm_gpu_devfreq, boost_work.work);
 260
 261         dev_pm_qos_update_request(&df->boost_freq, 0);
 262 }
 263
 264 void msm_devfreq_boost(struct msm_gpu *gpu, unsigned factor)
 265 {
 266         struct msm_gpu_devfreq *df = &gpu->devfreq;
 267         uint64_t freq;
 268
 269         if (!has_devfreq(gpu))
 270                 return;
 271
 272         freq = get_freq(gpu);
 273         freq *= factor;
 274
 275         /*
 276          * A nice little trap is that PM QoS operates in terms of KHz,
 277          * while devfreq operates in terms of Hz:
 278          */
 279         do_div(freq, HZ_PER_KHZ);
 280
 281         dev_pm_qos_update_request(&df->boost_freq, freq);
 282
 283         msm_hrtimer_queue_work(&df->boost_work,
 284                                ms_to_ktime(msm_devfreq_profile.polling_ms),
 285                                HRTIMER_MODE_REL);
 286 }
 287
 288 void msm_devfreq_active(struct msm_gpu *gpu)
 289 {
 290         struct msm_gpu_devfreq *df = &gpu->devfreq;
 291         unsigned int idle_time;
 292         unsigned long target_freq;
 293
 294         if (!has_devfreq(gpu))
 295                 return;
 296
 297         /*
 298          * Cancel any pending transition to idle frequency:
 299          */
 300         cancel_idle_work(df);
 301
 302         /*
 303          * Hold devfreq lock to synchronize with get_dev_status()/
 304          * target() callbacks
 305          */
 306         mutex_lock(&df->devfreq->lock);
 307
 308         target_freq = df->idle_freq;
 309
 310         idle_time = ktime_to_ms(ktime_sub(ktime_get(), df->idle_time));
 311
 312         df->idle_freq = 0;
 313
 314         /*
 315          * We could have become active again before the idle work had a
 316          * chance to run, in which case the df->idle_freq would have
 317          * still been zero.  In this case, no need to change freq.
 318          */
 319         if (target_freq)
 320                 msm_devfreq_target(&gpu->pdev->dev, &target_freq, 0);
 321
 322         mutex_unlock(&df->devfreq->lock);
 323
 324         /*
 325          * If we've been idle for a significant fraction of a polling
 326          * interval, then we won't meet the threshold of busyness for
 327          * the governor to ramp up the freq.. so give some boost
 328          */
 329         if (idle_time > msm_devfreq_profile.polling_ms) {
 330                 msm_devfreq_boost(gpu, 2);
 331         }
 332 }
 333
 334
 335 static void msm_devfreq_idle_work(struct kthread_work *work)
 336 {
 337         struct msm_gpu_devfreq *df = container_of(work,
 338                         struct msm_gpu_devfreq, idle_work.work);
 339         struct msm_gpu *gpu = container_of(df, struct msm_gpu, devfreq);
 340         struct msm_drm_private *priv = gpu->dev->dev_private;
 341         unsigned long idle_freq, target_freq = 0;
 342
 343         /*
 344          * Hold devfreq lock to synchronize with get_dev_status()/
 345          * target() callbacks
 346          */
 347         mutex_lock(&df->devfreq->lock);
 348
 349         idle_freq = get_freq(gpu);
 350
 351         if (priv->gpu_clamp_to_idle)
 352                 msm_devfreq_target(&gpu->pdev->dev, &target_freq, 0);
 353
 354         df->idle_time = ktime_get();
 355         df->idle_freq = idle_freq;
 356
 357         mutex_unlock(&df->devfreq->lock);
 358 }
 359
 360 void msm_devfreq_idle(struct msm_gpu *gpu)
 361 {
 362         struct msm_gpu_devfreq *df = &gpu->devfreq;
 363
 364         if (!has_devfreq(gpu))
 365                 return;
 366
 367         msm_hrtimer_queue_work(&df->idle_work, ms_to_ktime(1),
 368                                HRTIMER_MODE_REL);
 369 }