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 
13 static 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 
28 static 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 
41 static 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 
48 static 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 
78 static 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 
85 int 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 					 pfdev->comp->num_supplies);
106 	if (ret) {
107 		/* Continue if the optional regulator is missing */
108 		if (ret != -ENODEV) {
109 			if (ret != -EPROBE_DEFER)
110 				DRM_DEV_ERROR(dev, "Couldn't set OPP regulators\n");
111 			return ret;
112 		}
113 	}
114 
115 	ret = devm_pm_opp_of_add_table(dev);
116 	if (ret) {
117 		/* Optional, continue without devfreq */
118 		if (ret == -ENODEV)
119 			ret = 0;
120 		return ret;
121 	}
122 	pfdevfreq->opp_of_table_added = true;
123 
124 	spin_lock_init(&pfdevfreq->lock);
125 
126 	panfrost_devfreq_reset(pfdevfreq);
127 
128 	cur_freq = clk_get_rate(pfdev->clock);
129 
130 	opp = devfreq_recommended_opp(dev, &cur_freq, 0);
131 	if (IS_ERR(opp))
132 		return PTR_ERR(opp);
133 
134 	panfrost_devfreq_profile.initial_freq = cur_freq;
135 	dev_pm_opp_put(opp);
136 
137 	/*
138 	 * Setup default thresholds for the simple_ondemand governor.
139 	 * The values are chosen based on experiments.
140 	 */
141 	pfdevfreq->gov_data.upthreshold = 45;
142 	pfdevfreq->gov_data.downdifferential = 5;
143 
144 	devfreq = devm_devfreq_add_device(dev, &panfrost_devfreq_profile,
145 					  DEVFREQ_GOV_SIMPLE_ONDEMAND,
146 					  &pfdevfreq->gov_data);
147 	if (IS_ERR(devfreq)) {
148 		DRM_DEV_ERROR(dev, "Couldn't initialize GPU devfreq\n");
149 		return PTR_ERR(devfreq);
150 	}
151 	pfdevfreq->devfreq = devfreq;
152 
153 	cooling = devfreq_cooling_em_register(devfreq, NULL);
154 	if (IS_ERR(cooling))
155 		DRM_DEV_INFO(dev, "Failed to register cooling device\n");
156 	else
157 		pfdevfreq->cooling = cooling;
158 
159 	return 0;
160 }
161 
162 void panfrost_devfreq_fini(struct panfrost_device *pfdev)
163 {
164 	struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
165 
166 	if (pfdevfreq->cooling) {
167 		devfreq_cooling_unregister(pfdevfreq->cooling);
168 		pfdevfreq->cooling = NULL;
169 	}
170 }
171 
172 void panfrost_devfreq_resume(struct panfrost_device *pfdev)
173 {
174 	struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
175 
176 	if (!pfdevfreq->devfreq)
177 		return;
178 
179 	panfrost_devfreq_reset(pfdevfreq);
180 
181 	devfreq_resume_device(pfdevfreq->devfreq);
182 }
183 
184 void panfrost_devfreq_suspend(struct panfrost_device *pfdev)
185 {
186 	struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
187 
188 	if (!pfdevfreq->devfreq)
189 		return;
190 
191 	devfreq_suspend_device(pfdevfreq->devfreq);
192 }
193 
194 void panfrost_devfreq_record_busy(struct panfrost_devfreq *pfdevfreq)
195 {
196 	unsigned long irqflags;
197 
198 	if (!pfdevfreq->devfreq)
199 		return;
200 
201 	spin_lock_irqsave(&pfdevfreq->lock, irqflags);
202 
203 	panfrost_devfreq_update_utilization(pfdevfreq);
204 
205 	pfdevfreq->busy_count++;
206 
207 	spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
208 }
209 
210 void panfrost_devfreq_record_idle(struct panfrost_devfreq *pfdevfreq)
211 {
212 	unsigned long irqflags;
213 
214 	if (!pfdevfreq->devfreq)
215 		return;
216 
217 	spin_lock_irqsave(&pfdevfreq->lock, irqflags);
218 
219 	panfrost_devfreq_update_utilization(pfdevfreq);
220 
221 	WARN_ON(--pfdevfreq->busy_count < 0);
222 
223 	spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
224 }
225