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