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