1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright 2020 Linaro Limited
  4 *
  5 * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
  6 *
  7 * The DTPM CPU is based on the energy model. It hooks the CPU in the
  8 * DTPM tree which in turns update the power number by propagating the
  9 * power number from the CPU energy model information to the parents.
 10 *
 11 * The association between the power and the performance state, allows
 12 * to set the power of the CPU at the OPP granularity.
 13 *
 14 * The CPU hotplug is supported and the power numbers will be updated
 15 * if a CPU is hot plugged / unplugged.
 16 */
 17#include <linux/cpumask.h>
 18#include <linux/cpufreq.h>
 19#include <linux/cpuhotplug.h>
 20#include <linux/dtpm.h>
 21#include <linux/energy_model.h>
 22#include <linux/pm_qos.h>
 23#include <linux/slab.h>
 24#include <linux/units.h>
 25
 26static struct dtpm *__parent;
 27
 28static DEFINE_PER_CPU(struct dtpm *, dtpm_per_cpu);
 29
 30struct dtpm_cpu {
 31	struct freq_qos_request qos_req;
 32	int cpu;
 33};
 34
 35/*
 36 * When a new CPU is inserted at hotplug or boot time, add the power
 37 * contribution and update the dtpm tree.
 38 */
 39static int power_add(struct dtpm *dtpm, struct em_perf_domain *em)
 40{
 41	u64 power_min, power_max;
 42
 43	power_min = em->table[0].power;
 44	power_min *= MICROWATT_PER_MILLIWATT;
 45	power_min += dtpm->power_min;
 46
 47	power_max = em->table[em->nr_perf_states - 1].power;
 48	power_max *= MICROWATT_PER_MILLIWATT;
 49	power_max += dtpm->power_max;
 50
 51	return dtpm_update_power(dtpm, power_min, power_max);
 52}
 53
 54/*
 55 * When a CPU is unplugged, remove its power contribution from the
 56 * dtpm tree.
 57 */
 58static int power_sub(struct dtpm *dtpm, struct em_perf_domain *em)
 59{
 60	u64 power_min, power_max;
 61
 62	power_min = em->table[0].power;
 63	power_min *= MICROWATT_PER_MILLIWATT;
 64	power_min = dtpm->power_min - power_min;
 65
 66	power_max = em->table[em->nr_perf_states - 1].power;
 67	power_max *= MICROWATT_PER_MILLIWATT;
 68	power_max = dtpm->power_max - power_max;
 69
 70	return dtpm_update_power(dtpm, power_min, power_max);
 71}
 72
 73static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
 74{
 75	struct dtpm_cpu *dtpm_cpu = dtpm->private;
 76	struct em_perf_domain *pd;
 77	struct cpumask cpus;
 78	unsigned long freq;
 79	u64 power;
 80	int i, nr_cpus;
 81
 82	pd = em_cpu_get(dtpm_cpu->cpu);
 83
 84	cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus));
 85
 86	nr_cpus = cpumask_weight(&cpus);
 87
 88	for (i = 0; i < pd->nr_perf_states; i++) {
 89
 90		power = pd->table[i].power * MICROWATT_PER_MILLIWATT * nr_cpus;
 91
 92		if (power > power_limit)
 93			break;
 94	}
 95
 96	freq = pd->table[i - 1].frequency;
 97
 98	freq_qos_update_request(&dtpm_cpu->qos_req, freq);
 99
100	power_limit = pd->table[i - 1].power *
101		MICROWATT_PER_MILLIWATT * nr_cpus;
102
103	return power_limit;
104}
105
106static u64 get_pd_power_uw(struct dtpm *dtpm)
107{
108	struct dtpm_cpu *dtpm_cpu = dtpm->private;
109	struct em_perf_domain *pd;
110	struct cpumask cpus;
111	unsigned long freq;
112	int i, nr_cpus;
113
114	pd = em_cpu_get(dtpm_cpu->cpu);
115	freq = cpufreq_quick_get(dtpm_cpu->cpu);
116	cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus));
117	nr_cpus = cpumask_weight(&cpus);
118
119	for (i = 0; i < pd->nr_perf_states; i++) {
120
121		if (pd->table[i].frequency < freq)
122			continue;
123
124		return pd->table[i].power *
125			MICROWATT_PER_MILLIWATT * nr_cpus;
126	}
127
128	return 0;
129}
130
131static void pd_release(struct dtpm *dtpm)
132{
133	struct dtpm_cpu *dtpm_cpu = dtpm->private;
134
135	if (freq_qos_request_active(&dtpm_cpu->qos_req))
136		freq_qos_remove_request(&dtpm_cpu->qos_req);
137
138	kfree(dtpm_cpu);
139}
140
141static struct dtpm_ops dtpm_ops = {
142	.set_power_uw = set_pd_power_limit,
143	.get_power_uw = get_pd_power_uw,
144	.release = pd_release,
145};
146
147static int cpuhp_dtpm_cpu_offline(unsigned int cpu)
148{
149	struct cpufreq_policy *policy;
150	struct em_perf_domain *pd;
151	struct dtpm *dtpm;
152
153	policy = cpufreq_cpu_get(cpu);
154
155	if (!policy)
156		return 0;
157
158	pd = em_cpu_get(cpu);
159	if (!pd)
160		return -EINVAL;
161
162	dtpm = per_cpu(dtpm_per_cpu, cpu);
163
164	power_sub(dtpm, pd);
165
166	if (cpumask_weight(policy->cpus) != 1)
167		return 0;
168
169	for_each_cpu(cpu, policy->related_cpus)
170		per_cpu(dtpm_per_cpu, cpu) = NULL;
171
172	dtpm_unregister(dtpm);
173
174	return 0;
175}
176
177static int cpuhp_dtpm_cpu_online(unsigned int cpu)
178{
179	struct dtpm *dtpm;
180	struct dtpm_cpu *dtpm_cpu;
181	struct cpufreq_policy *policy;
182	struct em_perf_domain *pd;
183	char name[CPUFREQ_NAME_LEN];
184	int ret = -ENOMEM;
185
186	policy = cpufreq_cpu_get(cpu);
187
188	if (!policy)
189		return 0;
190
191	pd = em_cpu_get(cpu);
192	if (!pd)
193		return -EINVAL;
194
195	dtpm = per_cpu(dtpm_per_cpu, cpu);
196	if (dtpm)
197		return power_add(dtpm, pd);
198
199	dtpm = dtpm_alloc(&dtpm_ops);
200	if (!dtpm)
201		return -EINVAL;
202
203	dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);
204	if (!dtpm_cpu)
205		goto out_kfree_dtpm;
206
207	dtpm->private = dtpm_cpu;
208	dtpm_cpu->cpu = cpu;
209
210	for_each_cpu(cpu, policy->related_cpus)
211		per_cpu(dtpm_per_cpu, cpu) = dtpm;
212
213	sprintf(name, "cpu%d", dtpm_cpu->cpu);
214
215	ret = dtpm_register(name, dtpm, __parent);
216	if (ret)
217		goto out_kfree_dtpm_cpu;
218
219	ret = power_add(dtpm, pd);
220	if (ret)
221		goto out_dtpm_unregister;
222
223	ret = freq_qos_add_request(&policy->constraints,
224				   &dtpm_cpu->qos_req, FREQ_QOS_MAX,
225				   pd->table[pd->nr_perf_states - 1].frequency);
226	if (ret)
227		goto out_power_sub;
228
229	return 0;
230
231out_power_sub:
232	power_sub(dtpm, pd);
233
234out_dtpm_unregister:
235	dtpm_unregister(dtpm);
236	dtpm_cpu = NULL;
237	dtpm = NULL;
238
239out_kfree_dtpm_cpu:
240	for_each_cpu(cpu, policy->related_cpus)
241		per_cpu(dtpm_per_cpu, cpu) = NULL;
242	kfree(dtpm_cpu);
243
244out_kfree_dtpm:
245	kfree(dtpm);
246	return ret;
247}
248
249int dtpm_register_cpu(struct dtpm *parent)
250{
251	__parent = parent;
252
253	return cpuhp_setup_state(CPUHP_AP_DTPM_CPU_ONLINE,
254				 "dtpm_cpu:online",
255				 cpuhp_dtpm_cpu_online,
256				 cpuhp_dtpm_cpu_offline);
257}