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