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
 16static void panfrost_devfreq_update_utilization(struct panfrost_device *pfdev, int slot);
 17
 18static int panfrost_devfreq_target(struct device *dev, unsigned long *freq,
 19				   u32 flags)
 20{
 21	struct panfrost_device *pfdev = platform_get_drvdata(to_platform_device(dev));
 22	struct dev_pm_opp *opp;
 23	unsigned long old_clk_rate = pfdev->devfreq.cur_freq;
 24	unsigned long target_volt, target_rate;
 25	int err;
 26
 27	opp = devfreq_recommended_opp(dev, freq, flags);
 28	if (IS_ERR(opp))
 29		return PTR_ERR(opp);
 30
 31	target_rate = dev_pm_opp_get_freq(opp);
 32	target_volt = dev_pm_opp_get_voltage(opp);
 33	dev_pm_opp_put(opp);
 34
 35	if (old_clk_rate == target_rate)
 36		return 0;
 37
 38	/*
 39	 * If frequency scaling from low to high, adjust voltage first.
 40	 * If frequency scaling from high to low, adjust frequency first.
 41	 */
 42	if (old_clk_rate < target_rate) {
 43		err = regulator_set_voltage(pfdev->regulator, target_volt,
 44					    target_volt);
 45		if (err) {
 46			dev_err(dev, "Cannot set voltage %lu uV\n",
 47				target_volt);
 48			return err;
 49		}
 50	}
 51
 52	err = clk_set_rate(pfdev->clock, target_rate);
 53	if (err) {
 54		dev_err(dev, "Cannot set frequency %lu (%d)\n", target_rate,
 55			err);
 56		regulator_set_voltage(pfdev->regulator, pfdev->devfreq.cur_volt,
 57				      pfdev->devfreq.cur_volt);
 58		return err;
 59	}
 60
 61	if (old_clk_rate > target_rate) {
 62		err = regulator_set_voltage(pfdev->regulator, target_volt,
 63					    target_volt);
 64		if (err)
 65			dev_err(dev, "Cannot set voltage %lu uV\n", target_volt);
 66	}
 67
 68	pfdev->devfreq.cur_freq = target_rate;
 69	pfdev->devfreq.cur_volt = target_volt;
 70
 71	return 0;
 72}
 73
 74static void panfrost_devfreq_reset(struct panfrost_device *pfdev)
 75{
 76	ktime_t now = ktime_get();
 77	int i;
 78
 79	for (i = 0; i < NUM_JOB_SLOTS; i++) {
 80		pfdev->devfreq.slot[i].busy_time = 0;
 81		pfdev->devfreq.slot[i].idle_time = 0;
 82		pfdev->devfreq.slot[i].time_last_update = now;
 83	}
 84}
 85
 86static int panfrost_devfreq_get_dev_status(struct device *dev,
 87					   struct devfreq_dev_status *status)
 88{
 89	struct panfrost_device *pfdev = platform_get_drvdata(to_platform_device(dev));
 90	int i;
 91
 92	for (i = 0; i < NUM_JOB_SLOTS; i++) {
 93		panfrost_devfreq_update_utilization(pfdev, i);
 94	}
 95
 96	status->current_frequency = clk_get_rate(pfdev->clock);
 97	status->total_time = ktime_to_ns(ktime_add(pfdev->devfreq.slot[0].busy_time,
 98						   pfdev->devfreq.slot[0].idle_time));
 99
100	status->busy_time = 0;
101	for (i = 0; i < NUM_JOB_SLOTS; i++) {
102		status->busy_time += ktime_to_ns(pfdev->devfreq.slot[i].busy_time);
103	}
104
105	/* We're scheduling only to one core atm, so don't divide for now */
106	/* status->busy_time /= NUM_JOB_SLOTS; */
107
108	panfrost_devfreq_reset(pfdev);
109
110	dev_dbg(pfdev->dev, "busy %lu total %lu %lu %% freq %lu MHz\n", status->busy_time,
111		status->total_time,
112		status->busy_time / (status->total_time / 100),
113		status->current_frequency / 1000 / 1000);
114
115	return 0;
116}
117
118static int panfrost_devfreq_get_cur_freq(struct device *dev, unsigned long *freq)
119{
120	struct panfrost_device *pfdev = platform_get_drvdata(to_platform_device(dev));
121
122	*freq = pfdev->devfreq.cur_freq;
123
124	return 0;
125}
126
127static struct devfreq_dev_profile panfrost_devfreq_profile = {
128	.polling_ms = 50, /* ~3 frames */
129	.target = panfrost_devfreq_target,
130	.get_dev_status = panfrost_devfreq_get_dev_status,
131	.get_cur_freq = panfrost_devfreq_get_cur_freq,
132};
133
134int panfrost_devfreq_init(struct panfrost_device *pfdev)
135{
136	int ret;
137	struct dev_pm_opp *opp;
138
139	ret = dev_pm_opp_of_add_table(&pfdev->pdev->dev);
140	if (ret == -ENODEV) /* Optional, continue without devfreq */
141		return 0;
142	else if (ret)
143		return ret;
144
145	panfrost_devfreq_reset(pfdev);
146
147	pfdev->devfreq.cur_freq = clk_get_rate(pfdev->clock);
148
149	opp = devfreq_recommended_opp(&pfdev->pdev->dev, &pfdev->devfreq.cur_freq, 0);
150	if (IS_ERR(opp))
151		return PTR_ERR(opp);
152
153	panfrost_devfreq_profile.initial_freq = pfdev->devfreq.cur_freq;
154	dev_pm_opp_put(opp);
155
156	pfdev->devfreq.devfreq = devm_devfreq_add_device(&pfdev->pdev->dev,
157			&panfrost_devfreq_profile, DEVFREQ_GOV_SIMPLE_ONDEMAND,
158			NULL);
159	if (IS_ERR(pfdev->devfreq.devfreq)) {
160		DRM_DEV_ERROR(&pfdev->pdev->dev, "Couldn't initialize GPU devfreq\n");
161		ret = PTR_ERR(pfdev->devfreq.devfreq);
162		pfdev->devfreq.devfreq = NULL;
163		dev_pm_opp_of_remove_table(&pfdev->pdev->dev);
164		return ret;
165	}
166
167	return 0;
168}
169
170void panfrost_devfreq_fini(struct panfrost_device *pfdev)
171{
172	dev_pm_opp_of_remove_table(&pfdev->pdev->dev);
173}
174
175void panfrost_devfreq_resume(struct panfrost_device *pfdev)
176{
177	int i;
178
179	if (!pfdev->devfreq.devfreq)
180		return;
181
182	panfrost_devfreq_reset(pfdev);
183	for (i = 0; i < NUM_JOB_SLOTS; i++)
184		pfdev->devfreq.slot[i].busy = false;
185
186	devfreq_resume_device(pfdev->devfreq.devfreq);
187}
188
189void panfrost_devfreq_suspend(struct panfrost_device *pfdev)
190{
191	if (!pfdev->devfreq.devfreq)
192		return;
193
194	devfreq_suspend_device(pfdev->devfreq.devfreq);
195}
196
197static void panfrost_devfreq_update_utilization(struct panfrost_device *pfdev, int slot)
198{
199	struct panfrost_devfreq_slot *devfreq_slot = &pfdev->devfreq.slot[slot];
200	ktime_t now;
201	ktime_t last;
202
203	if (!pfdev->devfreq.devfreq)
204		return;
205
206	now = ktime_get();
207	last = pfdev->devfreq.slot[slot].time_last_update;
208
209	/* If we last recorded a transition to busy, we have been idle since */
210	if (devfreq_slot->busy)
211		pfdev->devfreq.slot[slot].busy_time += ktime_sub(now, last);
212	else
213		pfdev->devfreq.slot[slot].idle_time += ktime_sub(now, last);
214
215	pfdev->devfreq.slot[slot].time_last_update = now;
216}
217
218/* The job scheduler is expected to call this at every transition busy <-> idle */
219void panfrost_devfreq_record_transition(struct panfrost_device *pfdev, int slot)
220{
221	struct panfrost_devfreq_slot *devfreq_slot = &pfdev->devfreq.slot[slot];
222
223	panfrost_devfreq_update_utilization(pfdev, slot);
224	devfreq_slot->busy = !devfreq_slot->busy;
225}