1// SPDX-License-Identifier: GPL-2.0
  2/* Copyright 2019 Collabora ltd. */
  3#include <linux/devfreq.h>
  4#include <linux/devfreq_cooling.h>
  5#include <linux/platform_device.h>
  6#include <linux/pm_opp.h>
  7#include <linux/clk.h>
  8#include <linux/regulator/consumer.h>
  9
 10#include "panfrost_device.h"
 11#include "panfrost_devfreq.h"
 12#include "panfrost_features.h"
 13#include "panfrost_issues.h"
 14#include "panfrost_gpu.h"
 15#include "panfrost_regs.h"
 16
 17static void panfrost_devfreq_update_utilization(struct panfrost_device *pfdev);
 18
 19static int panfrost_devfreq_target(struct device *dev, unsigned long *freq,
 20				   u32 flags)
 21{
 22	struct dev_pm_opp *opp;
 23	int err;
 24
 25	opp = devfreq_recommended_opp(dev, freq, flags);
 26	if (IS_ERR(opp))
 27		return PTR_ERR(opp);
 28	dev_pm_opp_put(opp);
 29
 30	err = dev_pm_opp_set_rate(dev, *freq);
 31	if (err)
 32		return err;
 33
 34	return 0;
 35}
 36
 37static void panfrost_devfreq_reset(struct panfrost_device *pfdev)
 38{
 39	pfdev->devfreq.busy_time = 0;
 40	pfdev->devfreq.idle_time = 0;
 41	pfdev->devfreq.time_last_update = ktime_get();
 42}
 43
 44static int panfrost_devfreq_get_dev_status(struct device *dev,
 45					   struct devfreq_dev_status *status)
 46{
 47	struct panfrost_device *pfdev = dev_get_drvdata(dev);
 48
 49	panfrost_devfreq_update_utilization(pfdev);
 50
 51	status->current_frequency = clk_get_rate(pfdev->clock);
 52	status->total_time = ktime_to_ns(ktime_add(pfdev->devfreq.busy_time,
 53						   pfdev->devfreq.idle_time));
 54
 55	status->busy_time = ktime_to_ns(pfdev->devfreq.busy_time);
 56
 57	panfrost_devfreq_reset(pfdev);
 58
 59	dev_dbg(pfdev->dev, "busy %lu total %lu %lu %% freq %lu MHz\n", status->busy_time,
 60		status->total_time,
 61		status->busy_time / (status->total_time / 100),
 62		status->current_frequency / 1000 / 1000);
 63
 64	return 0;
 65}
 66
 67static struct devfreq_dev_profile panfrost_devfreq_profile = {
 68	.polling_ms = 50, /* ~3 frames */
 69	.target = panfrost_devfreq_target,
 70	.get_dev_status = panfrost_devfreq_get_dev_status,
 71};
 72
 73int panfrost_devfreq_init(struct panfrost_device *pfdev)
 74{
 75	int ret;
 76	struct dev_pm_opp *opp;
 77	unsigned long cur_freq;
 78	struct device *dev = &pfdev->pdev->dev;
 79	struct devfreq *devfreq;
 80	struct thermal_cooling_device *cooling;
 81
 82	ret = dev_pm_opp_of_add_table(dev);
 83	if (ret == -ENODEV) /* Optional, continue without devfreq */
 84		return 0;
 85	else if (ret)
 86		return ret;
 87
 88	panfrost_devfreq_reset(pfdev);
 89
 90	cur_freq = clk_get_rate(pfdev->clock);
 91
 92	opp = devfreq_recommended_opp(dev, &cur_freq, 0);
 93	if (IS_ERR(opp))
 94		return PTR_ERR(opp);
 95
 96	panfrost_devfreq_profile.initial_freq = cur_freq;
 97	dev_pm_opp_put(opp);
 98
 99	devfreq = devm_devfreq_add_device(dev, &panfrost_devfreq_profile,
100					  DEVFREQ_GOV_SIMPLE_ONDEMAND, NULL);
101	if (IS_ERR(devfreq)) {
102		DRM_DEV_ERROR(dev, "Couldn't initialize GPU devfreq\n");
103		dev_pm_opp_of_remove_table(dev);
104		return PTR_ERR(devfreq);
105	}
106	pfdev->devfreq.devfreq = devfreq;
107
108	cooling = of_devfreq_cooling_register(dev->of_node, devfreq);
109	if (IS_ERR(cooling))
110		DRM_DEV_INFO(dev, "Failed to register cooling device\n");
111	else
112		pfdev->devfreq.cooling = cooling;
113
114	return 0;
115}
116
117void panfrost_devfreq_fini(struct panfrost_device *pfdev)
118{
119	if (pfdev->devfreq.cooling)
120		devfreq_cooling_unregister(pfdev->devfreq.cooling);
121	dev_pm_opp_of_remove_table(&pfdev->pdev->dev);
122}
123
124void panfrost_devfreq_resume(struct panfrost_device *pfdev)
125{
126	if (!pfdev->devfreq.devfreq)
127		return;
128
129	panfrost_devfreq_reset(pfdev);
130
131	devfreq_resume_device(pfdev->devfreq.devfreq);
132}
133
134void panfrost_devfreq_suspend(struct panfrost_device *pfdev)
135{
136	if (!pfdev->devfreq.devfreq)
137		return;
138
139	devfreq_suspend_device(pfdev->devfreq.devfreq);
140}
141
142static void panfrost_devfreq_update_utilization(struct panfrost_device *pfdev)
143{
144	ktime_t now;
145	ktime_t last;
146
147	if (!pfdev->devfreq.devfreq)
148		return;
149
150	now = ktime_get();
151	last = pfdev->devfreq.time_last_update;
152
153	if (atomic_read(&pfdev->devfreq.busy_count) > 0)
154		pfdev->devfreq.busy_time += ktime_sub(now, last);
155	else
156		pfdev->devfreq.idle_time += ktime_sub(now, last);
157
158	pfdev->devfreq.time_last_update = now;
159}
160
161void panfrost_devfreq_record_busy(struct panfrost_device *pfdev)
162{
163	panfrost_devfreq_update_utilization(pfdev);
164	atomic_inc(&pfdev->devfreq.busy_count);
165}
166
167void panfrost_devfreq_record_idle(struct panfrost_device *pfdev)
168{
169	int count;
170
171	panfrost_devfreq_update_utilization(pfdev);
172	count = atomic_dec_if_positive(&pfdev->devfreq.busy_count);
173	WARN_ON(count < 0);
174}