1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright 2021 Linaro Limited
4 *
5 * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
6 *
7 * The devfreq device combined with the energy model and the load can
8 * give an estimation of the power consumption as well as limiting the
9 * power.
10 *
11 */
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/cpumask.h>
15#include <linux/devfreq.h>
16#include <linux/dtpm.h>
17#include <linux/energy_model.h>
18#include <linux/of.h>
19#include <linux/pm_qos.h>
20#include <linux/slab.h>
21#include <linux/units.h>
22
23struct dtpm_devfreq {
24 struct dtpm dtpm;
25 struct dev_pm_qos_request qos_req;
26 struct devfreq *devfreq;
27};
28
29static struct dtpm_devfreq *to_dtpm_devfreq(struct dtpm *dtpm)
30{
31 return container_of(dtpm, struct dtpm_devfreq, dtpm);
32}
33
34static int update_pd_power_uw(struct dtpm *dtpm)
35{
36 struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
37 struct devfreq *devfreq = dtpm_devfreq->devfreq;
38 struct device *dev = devfreq->dev.parent;
39 struct em_perf_domain *pd = em_pd_get(dev);
40 struct em_perf_state *table;
41
42 rcu_read_lock();
43 table = em_perf_state_from_pd(pd);
44
45 dtpm->power_min = table[0].power;
46
47 dtpm->power_max = table[pd->nr_perf_states - 1].power;
48
49 rcu_read_unlock();
50 return 0;
51}
52
53static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
54{
55 struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
56 struct devfreq *devfreq = dtpm_devfreq->devfreq;
57 struct device *dev = devfreq->dev.parent;
58 struct em_perf_domain *pd = em_pd_get(dev);
59 struct em_perf_state *table;
60 unsigned long freq;
61 int i;
62
63 rcu_read_lock();
64 table = em_perf_state_from_pd(pd);
65 for (i = 0; i < pd->nr_perf_states; i++) {
66 if (table[i].power > power_limit)
67 break;
68 }
69
70 freq = table[i - 1].frequency;
71 power_limit = table[i - 1].power;
72 rcu_read_unlock();
73
74 dev_pm_qos_update_request(req: &dtpm_devfreq->qos_req, new_value: freq);
75
76 return power_limit;
77}
78
79static void _normalize_load(struct devfreq_dev_status *status)
80{
81 if (status->total_time > 0xfffff) {
82 status->total_time >>= 10;
83 status->busy_time >>= 10;
84 }
85
86 status->busy_time <<= 10;
87 status->busy_time /= status->total_time ? : 1;
88
89 status->busy_time = status->busy_time ? : 1;
90 status->total_time = 1024;
91}
92
93static u64 get_pd_power_uw(struct dtpm *dtpm)
94{
95 struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
96 struct devfreq *devfreq = dtpm_devfreq->devfreq;
97 struct device *dev = devfreq->dev.parent;
98 struct em_perf_domain *pd = em_pd_get(dev);
99 struct devfreq_dev_status status;
100 struct em_perf_state *table;
101 unsigned long freq;
102 u64 power = 0;
103 int i;
104
105 mutex_lock(&devfreq->lock);
106 status = devfreq->last_status;
107 mutex_unlock(lock: &devfreq->lock);
108
109 freq = DIV_ROUND_UP(status.current_frequency, HZ_PER_KHZ);
110 _normalize_load(status: &status);
111
112 rcu_read_lock();
113 table = em_perf_state_from_pd(pd);
114 for (i = 0; i < pd->nr_perf_states; i++) {
115
116 if (table[i].frequency < freq)
117 continue;
118
119 power = table[i].power;
120 power *= status.busy_time;
121 power >>= 10;
122
123 break;
124 }
125 rcu_read_unlock();
126
127 return power;
128}
129
130static void pd_release(struct dtpm *dtpm)
131{
132 struct dtpm_devfreq *dtpm_devfreq = to_dtpm_devfreq(dtpm);
133
134 if (dev_pm_qos_request_active(req: &dtpm_devfreq->qos_req))
135 dev_pm_qos_remove_request(req: &dtpm_devfreq->qos_req);
136
137 kfree(objp: dtpm_devfreq);
138}
139
140static struct dtpm_ops dtpm_ops = {
141 .set_power_uw = set_pd_power_limit,
142 .get_power_uw = get_pd_power_uw,
143 .update_power_uw = update_pd_power_uw,
144 .release = pd_release,
145};
146
147static int __dtpm_devfreq_setup(struct devfreq *devfreq, struct dtpm *parent)
148{
149 struct device *dev = devfreq->dev.parent;
150 struct dtpm_devfreq *dtpm_devfreq;
151 struct em_perf_domain *pd;
152 int ret = -ENOMEM;
153
154 pd = em_pd_get(dev);
155 if (!pd) {
156 ret = dev_pm_opp_of_register_em(dev, NULL);
157 if (ret) {
158 pr_err("No energy model available for '%s'\n", dev_name(dev));
159 return -EINVAL;
160 }
161 }
162
163 dtpm_devfreq = kzalloc(sizeof(*dtpm_devfreq), GFP_KERNEL);
164 if (!dtpm_devfreq)
165 return -ENOMEM;
166
167 dtpm_init(dtpm: &dtpm_devfreq->dtpm, ops: &dtpm_ops);
168
169 dtpm_devfreq->devfreq = devfreq;
170
171 ret = dtpm_register(name: dev_name(dev), dtpm: &dtpm_devfreq->dtpm, parent);
172 if (ret) {
173 pr_err("Failed to register '%s': %d\n", dev_name(dev), ret);
174 kfree(objp: dtpm_devfreq);
175 return ret;
176 }
177
178 ret = dev_pm_qos_add_request(dev, req: &dtpm_devfreq->qos_req,
179 type: DEV_PM_QOS_MAX_FREQUENCY,
180 PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
181 if (ret < 0) {
182 pr_err("Failed to add QoS request: %d\n", ret);
183 goto out_dtpm_unregister;
184 }
185
186 dtpm_update_power(dtpm: &dtpm_devfreq->dtpm);
187
188 return 0;
189
190out_dtpm_unregister:
191 dtpm_unregister(dtpm: &dtpm_devfreq->dtpm);
192
193 return ret;
194}
195
196static int dtpm_devfreq_setup(struct dtpm *dtpm, struct device_node *np)
197{
198 struct devfreq *devfreq;
199
200 devfreq = devfreq_get_devfreq_by_node(node: np);
201 if (IS_ERR(ptr: devfreq))
202 return 0;
203
204 return __dtpm_devfreq_setup(devfreq, parent: dtpm);
205}
206
207struct dtpm_subsys_ops dtpm_devfreq_ops = {
208 .name = KBUILD_MODNAME,
209 .setup = dtpm_devfreq_setup,
210};
211

source code of linux/drivers/powercap/dtpm_devfreq.c