1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2013 Red Hat
  4 * Author: Rob Clark <robdclark@gmail.com>
  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
 19static 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
 59static 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
 77static 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
115static 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
122static 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
130static void msm_devfreq_boost_work(struct kthread_work *work);
131static void msm_devfreq_idle_work(struct kthread_work *work);
132
133static bool has_devfreq(struct msm_gpu *gpu)
134{
135	struct msm_gpu_devfreq *df = &gpu->devfreq;
136	return !!df->devfreq;
137}
138
139void 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	int ret;
144
145	/* We need target support to do devfreq */
146	if (!gpu->funcs->gpu_busy)
147		return;
148
149	/*
150	 * Setup default values for simple_ondemand governor tuning.  We
151	 * want to throttle up at 50% load for the double-buffer case,
152	 * where due to stalling waiting for vblank we could get stuck
153	 * at (for ex) 30fps at 50% utilization.
154	 */
155	priv->gpu_devfreq_config.upthreshold = 50;
156	priv->gpu_devfreq_config.downdifferential = 10;
157
158	mutex_init(&df->lock);
159
160	ret = dev_pm_qos_add_request(&gpu->pdev->dev, &df->boost_freq,
161				     DEV_PM_QOS_MIN_FREQUENCY, 0);
162	if (ret < 0) {
163		DRM_DEV_ERROR(&gpu->pdev->dev, "Couldn't initialize QoS\n");
164		return;
165	}
166
167	msm_devfreq_profile.initial_freq = gpu->fast_rate;
168
169	/*
170	 * Don't set the freq_table or max_state and let devfreq build the table
171	 * from OPP
172	 * After a deferred probe, these may have be left to non-zero values,
173	 * so set them back to zero before creating the devfreq device
174	 */
175	msm_devfreq_profile.freq_table = NULL;
176	msm_devfreq_profile.max_state = 0;
177
178	df->devfreq = devm_devfreq_add_device(&gpu->pdev->dev,
179			&msm_devfreq_profile, DEVFREQ_GOV_SIMPLE_ONDEMAND,
180			&priv->gpu_devfreq_config);
181
182	if (IS_ERR(df->devfreq)) {
183		DRM_DEV_ERROR(&gpu->pdev->dev, "Couldn't initialize GPU devfreq\n");
184		dev_pm_qos_remove_request(&df->boost_freq);
185		df->devfreq = NULL;
186		return;
187	}
188
189	devfreq_suspend_device(df->devfreq);
190
191	gpu->cooling = of_devfreq_cooling_register(gpu->pdev->dev.of_node, df->devfreq);
192	if (IS_ERR(gpu->cooling)) {
193		DRM_DEV_ERROR(&gpu->pdev->dev,
194				"Couldn't register GPU cooling device\n");
195		gpu->cooling = NULL;
196	}
197
198	msm_hrtimer_work_init(&df->boost_work, gpu->worker, msm_devfreq_boost_work,
199			      CLOCK_MONOTONIC, HRTIMER_MODE_REL);
200	msm_hrtimer_work_init(&df->idle_work, gpu->worker, msm_devfreq_idle_work,
201			      CLOCK_MONOTONIC, HRTIMER_MODE_REL);
202}
203
204static void cancel_idle_work(struct msm_gpu_devfreq *df)
205{
206	hrtimer_cancel(&df->idle_work.timer);
207	kthread_cancel_work_sync(&df->idle_work.work);
208}
209
210static void cancel_boost_work(struct msm_gpu_devfreq *df)
211{
212	hrtimer_cancel(&df->boost_work.timer);
213	kthread_cancel_work_sync(&df->boost_work.work);
214}
215
216void msm_devfreq_cleanup(struct msm_gpu *gpu)
217{
218	struct msm_gpu_devfreq *df = &gpu->devfreq;
219
220	if (!has_devfreq(gpu))
221		return;
222
223	devfreq_cooling_unregister(gpu->cooling);
224	dev_pm_qos_remove_request(&df->boost_freq);
225}
226
227void msm_devfreq_resume(struct msm_gpu *gpu)
228{
229	struct msm_gpu_devfreq *df = &gpu->devfreq;
230	unsigned long sample_rate;
231
232	if (!has_devfreq(gpu))
233		return;
234
235	mutex_lock(&df->lock);
236	df->busy_cycles = gpu->funcs->gpu_busy(gpu, &sample_rate);
237	df->time = ktime_get();
238	df->suspended = false;
239	mutex_unlock(&df->lock);
240
241	devfreq_resume_device(df->devfreq);
242}
243
244void msm_devfreq_suspend(struct msm_gpu *gpu)
245{
246	struct msm_gpu_devfreq *df = &gpu->devfreq;
247
248	if (!has_devfreq(gpu))
249		return;
250
251	mutex_lock(&df->lock);
252	df->suspended = true;
253	mutex_unlock(&df->lock);
254
255	devfreq_suspend_device(df->devfreq);
256
257	cancel_idle_work(df);
258	cancel_boost_work(df);
259}
260
261static void msm_devfreq_boost_work(struct kthread_work *work)
262{
263	struct msm_gpu_devfreq *df = container_of(work,
264			struct msm_gpu_devfreq, boost_work.work);
265
266	dev_pm_qos_update_request(&df->boost_freq, 0);
267}
268
269void msm_devfreq_boost(struct msm_gpu *gpu, unsigned factor)
270{
271	struct msm_gpu_devfreq *df = &gpu->devfreq;
272	uint64_t freq;
273
274	if (!has_devfreq(gpu))
275		return;
276
277	freq = get_freq(gpu);
278	freq *= factor;
279
280	/*
281	 * A nice little trap is that PM QoS operates in terms of KHz,
282	 * while devfreq operates in terms of Hz:
283	 */
284	do_div(freq, HZ_PER_KHZ);
285
286	dev_pm_qos_update_request(&df->boost_freq, freq);
287
288	msm_hrtimer_queue_work(&df->boost_work,
289			       ms_to_ktime(msm_devfreq_profile.polling_ms),
290			       HRTIMER_MODE_REL);
291}
292
293void msm_devfreq_active(struct msm_gpu *gpu)
294{
295	struct msm_gpu_devfreq *df = &gpu->devfreq;
296	unsigned int idle_time;
297	unsigned long target_freq;
298
299	if (!has_devfreq(gpu))
300		return;
301
302	/*
303	 * Cancel any pending transition to idle frequency:
304	 */
305	cancel_idle_work(df);
306
307	/*
308	 * Hold devfreq lock to synchronize with get_dev_status()/
309	 * target() callbacks
310	 */
311	mutex_lock(&df->devfreq->lock);
312
313	target_freq = df->idle_freq;
314
315	idle_time = ktime_to_ms(ktime_sub(ktime_get(), df->idle_time));
316
317	df->idle_freq = 0;
318
319	/*
320	 * We could have become active again before the idle work had a
321	 * chance to run, in which case the df->idle_freq would have
322	 * still been zero.  In this case, no need to change freq.
323	 */
324	if (target_freq)
325		msm_devfreq_target(&gpu->pdev->dev, &target_freq, 0);
326
327	mutex_unlock(&df->devfreq->lock);
328
329	/*
330	 * If we've been idle for a significant fraction of a polling
331	 * interval, then we won't meet the threshold of busyness for
332	 * the governor to ramp up the freq.. so give some boost
333	 */
334	if (idle_time > msm_devfreq_profile.polling_ms) {
335		msm_devfreq_boost(gpu, 2);
336	}
337}
338
339
340static void msm_devfreq_idle_work(struct kthread_work *work)
341{
342	struct msm_gpu_devfreq *df = container_of(work,
343			struct msm_gpu_devfreq, idle_work.work);
344	struct msm_gpu *gpu = container_of(df, struct msm_gpu, devfreq);
345	struct msm_drm_private *priv = gpu->dev->dev_private;
346	unsigned long idle_freq, target_freq = 0;
347
348	/*
349	 * Hold devfreq lock to synchronize with get_dev_status()/
350	 * target() callbacks
351	 */
352	mutex_lock(&df->devfreq->lock);
353
354	idle_freq = get_freq(gpu);
355
356	if (priv->gpu_clamp_to_idle)
357		msm_devfreq_target(&gpu->pdev->dev, &target_freq, 0);
358
359	df->idle_time = ktime_get();
360	df->idle_freq = idle_freq;
361
362	mutex_unlock(&df->devfreq->lock);
363}
364
365void msm_devfreq_idle(struct msm_gpu *gpu)
366{
367	struct msm_gpu_devfreq *df = &gpu->devfreq;
368
369	if (!has_devfreq(gpu))
370		return;
371
372	msm_hrtimer_queue_work(&df->idle_work, ms_to_ktime(1),
373			       HRTIMER_MODE_REL);
374}