summaryrefslogtreecommitdiffstats
path: root/drivers/powercap/dtpm_cpu.c
blob: 9193c3b8edebe9bf0cebc9a0d9d7084518a91c2d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2020 Linaro Limited
 *
 * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
 *
 * The DTPM CPU is based on the energy model. It hooks the CPU in the
 * DTPM tree which in turns update the power number by propagating the
 * power number from the CPU energy model information to the parents.
 *
 * The association between the power and the performance state, allows
 * to set the power of the CPU at the OPP granularity.
 *
 * The CPU hotplug is supported and the power numbers will be updated
 * if a CPU is hot plugged / unplugged.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cpumask.h>
#include <linux/cpufreq.h>
#include <linux/cpuhotplug.h>
#include <linux/dtpm.h>
#include <linux/energy_model.h>
#include <linux/of.h>
#include <linux/pm_qos.h>
#include <linux/slab.h>

struct dtpm_cpu {
	struct dtpm dtpm;
	struct freq_qos_request qos_req;
	int cpu;
};

static DEFINE_PER_CPU(struct dtpm_cpu *, dtpm_per_cpu);

static struct dtpm_cpu *to_dtpm_cpu(struct dtpm *dtpm)
{
	return container_of(dtpm, struct dtpm_cpu, dtpm);
}

static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
{
	struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
	struct em_perf_domain *pd = em_cpu_get(dtpm_cpu->cpu);
	struct cpumask cpus;
	unsigned long freq;
	u64 power;
	int i, nr_cpus;

	cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus));
	nr_cpus = cpumask_weight(&cpus);

	for (i = 0; i < pd->nr_perf_states; i++) {

		power = pd->table[i].power * nr_cpus;

		if (power > power_limit)
			break;
	}

	freq = pd->table[i - 1].frequency;

	freq_qos_update_request(&dtpm_cpu->qos_req, freq);

	power_limit = pd->table[i - 1].power * nr_cpus;

	return power_limit;
}

static u64 scale_pd_power_uw(struct cpumask *pd_mask, u64 power)
{
	unsigned long max, sum_util = 0;
	int cpu;

	/*
	 * The capacity is the same for all CPUs belonging to
	 * the same perf domain.
	 */
	max = arch_scale_cpu_capacity(cpumask_first(pd_mask));

	for_each_cpu_and(cpu, pd_mask, cpu_online_mask)
		sum_util += sched_cpu_util(cpu);

	return (power * ((sum_util << 10) / max)) >> 10;
}

static u64 get_pd_power_uw(struct dtpm *dtpm)
{
	struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
	struct em_perf_domain *pd;
	struct cpumask *pd_mask;
	unsigned long freq;
	int i;

	pd = em_cpu_get(dtpm_cpu->cpu);

	pd_mask = em_span_cpus(pd);

	freq = cpufreq_quick_get(dtpm_cpu->cpu);

	for (i = 0; i < pd->nr_perf_states; i++) {

		if (pd->table[i].frequency < freq)
			continue;

		return scale_pd_power_uw(pd_mask, pd->table[i].power);
	}

	return 0;
}

static int update_pd_power_uw(struct dtpm *dtpm)
{
	struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
	struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu);
	struct cpumask cpus;
	int nr_cpus;

	cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus));
	nr_cpus = cpumask_weight(&cpus);

	dtpm->power_min = em->table[0].power;
	dtpm->power_min *= nr_cpus;

	dtpm->power_max = em->table[em->nr_perf_states - 1].power;
	dtpm->power_max *= nr_cpus;

	return 0;
}

static void pd_release(struct dtpm *dtpm)
{
	struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
	struct cpufreq_policy *policy;

	if (freq_qos_request_active(&dtpm_cpu->qos_req))
		freq_qos_remove_request(&dtpm_cpu->qos_req);

	policy = cpufreq_cpu_get(dtpm_cpu->cpu);
	if (policy) {
		for_each_cpu(dtpm_cpu->cpu, policy->related_cpus)
			per_cpu(dtpm_per_cpu, dtpm_cpu->cpu) = NULL;

		cpufreq_cpu_put(policy);
	}
	
	kfree(dtpm_cpu);
}

static struct dtpm_ops dtpm_ops = {
	.set_power_uw	 = set_pd_power_limit,
	.get_power_uw	 = get_pd_power_uw,
	.update_power_uw = update_pd_power_uw,
	.release	 = pd_release,
};

static int cpuhp_dtpm_cpu_offline(unsigned int cpu)
{
	struct dtpm_cpu *dtpm_cpu;

	dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
	if (dtpm_cpu)
		dtpm_update_power(&dtpm_cpu->dtpm);

	return 0;
}

static int cpuhp_dtpm_cpu_online(unsigned int cpu)
{
	struct dtpm_cpu *dtpm_cpu;

	dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
	if (dtpm_cpu)
		return dtpm_update_power(&dtpm_cpu->dtpm);

	return 0;
}

static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
{
	struct dtpm_cpu *dtpm_cpu;
	struct cpufreq_policy *policy;
	struct em_perf_domain *pd;
	char name[CPUFREQ_NAME_LEN];
	int ret = -ENOMEM;

	dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
	if (dtpm_cpu)
		return 0;

	policy = cpufreq_cpu_get(cpu);
	if (!policy)
		return 0;

	pd = em_cpu_get(cpu);
	if (!pd || em_is_artificial(pd)) {
		ret = -EINVAL;
		goto release_policy;
	}

	dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);
	if (!dtpm_cpu) {
		ret = -ENOMEM;
		goto release_policy;
	}

	dtpm_init(&dtpm_cpu->dtpm, &dtpm_ops);
	dtpm_cpu->cpu = cpu;

	for_each_cpu(cpu, policy->related_cpus)
		per_cpu(dtpm_per_cpu, cpu) = dtpm_cpu;

	snprintf(name, sizeof(name), "cpu%d-cpufreq", dtpm_cpu->cpu);

	ret = dtpm_register(name, &dtpm_cpu->dtpm, parent);
	if (ret)
		goto out_kfree_dtpm_cpu;

	ret = freq_qos_add_request(&policy->constraints,
				   &dtpm_cpu->qos_req, FREQ_QOS_MAX,
				   pd->table[pd->nr_perf_states - 1].frequency);
	if (ret)
		goto out_dtpm_unregister;

	cpufreq_cpu_put(policy);
	return 0;

out_dtpm_unregister:
	dtpm_unregister(&dtpm_cpu->dtpm);
	dtpm_cpu = NULL;

out_kfree_dtpm_cpu:
	for_each_cpu(cpu, policy->related_cpus)
		per_cpu(dtpm_per_cpu, cpu) = NULL;
	kfree(dtpm_cpu);

release_policy:
	cpufreq_cpu_put(policy);
	return ret;
}

static int dtpm_cpu_setup(struct dtpm *dtpm, struct device_node *np)
{
	int cpu;

	cpu = of_cpu_node_to_id(np);
	if (cpu < 0)
		return 0;

	return __dtpm_cpu_setup(cpu, dtpm);
}

static int dtpm_cpu_init(void)
{
	int ret;

	/*
	 * The callbacks at CPU hotplug time are calling
	 * dtpm_update_power() which in turns calls update_pd_power().
	 *
	 * The function update_pd_power() uses the online mask to
	 * figure out the power consumption limits.
	 *
	 * At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU
	 * online mask when the cpuhp_dtpm_cpu_online function is
	 * called, but the CPU is still in the online mask for the
	 * tear down callback. So the power can not be updated when
	 * the CPU is unplugged.
	 *
	 * At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as
	 * above. The CPU online mask is not up to date when the CPU
	 * is plugged in.
	 *
	 * For this reason, we need to call the online and offline
	 * callbacks at different moments when the CPU online mask is
	 * consistent with the power numbers we want to update.
	 */
	ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline",
				NULL, cpuhp_dtpm_cpu_offline);
	if (ret < 0)
		return ret;

	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online",
				cpuhp_dtpm_cpu_online, NULL);
	if (ret < 0)
		return ret;

	return 0;
}

static void dtpm_cpu_exit(void)
{
	cpuhp_remove_state_nocalls(CPUHP_AP_ONLINE_DYN);
	cpuhp_remove_state_nocalls(CPUHP_AP_DTPM_CPU_DEAD);
}

struct dtpm_subsys_ops dtpm_cpu_ops = {
	.name = KBUILD_MODNAME,
	.init = dtpm_cpu_init,
	.exit = dtpm_cpu_exit,
	.setup = dtpm_cpu_setup,
};