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 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
18 | |
19 | #include <linux/cpumask.h> |
20 | #include <linux/cpufreq.h> |
21 | #include <linux/cpuhotplug.h> |
22 | #include <linux/dtpm.h> |
23 | #include <linux/energy_model.h> |
24 | #include <linux/of.h> |
25 | #include <linux/pm_qos.h> |
26 | #include <linux/slab.h> |
27 | |
28 | struct dtpm_cpu { |
29 | struct dtpm dtpm; |
30 | struct freq_qos_request qos_req; |
31 | int cpu; |
32 | }; |
33 | |
34 | static DEFINE_PER_CPU(struct dtpm_cpu *, dtpm_per_cpu); |
35 | |
36 | static struct dtpm_cpu *to_dtpm_cpu(struct dtpm *dtpm) |
37 | { |
38 | return container_of(dtpm, struct dtpm_cpu, dtpm); |
39 | } |
40 | |
41 | static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit) |
42 | { |
43 | struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
44 | struct em_perf_domain *pd = em_cpu_get(cpu: dtpm_cpu->cpu); |
45 | struct em_perf_state *table; |
46 | struct cpumask cpus; |
47 | unsigned long freq; |
48 | u64 power; |
49 | int i, nr_cpus; |
50 | |
51 | cpumask_and(dstp: &cpus, cpu_online_mask, to_cpumask(pd->cpus)); |
52 | nr_cpus = cpumask_weight(srcp: &cpus); |
53 | |
54 | rcu_read_lock(); |
55 | table = em_perf_state_from_pd(pd); |
56 | for (i = 0; i < pd->nr_perf_states; i++) { |
57 | |
58 | power = table[i].power * nr_cpus; |
59 | |
60 | if (power > power_limit) |
61 | break; |
62 | } |
63 | |
64 | freq = table[i - 1].frequency; |
65 | power_limit = table[i - 1].power * nr_cpus; |
66 | rcu_read_unlock(); |
67 | |
68 | freq_qos_update_request(req: &dtpm_cpu->qos_req, new_value: freq); |
69 | |
70 | return power_limit; |
71 | } |
72 | |
73 | static u64 scale_pd_power_uw(struct cpumask *pd_mask, u64 power) |
74 | { |
75 | unsigned long max, sum_util = 0; |
76 | int cpu; |
77 | |
78 | /* |
79 | * The capacity is the same for all CPUs belonging to |
80 | * the same perf domain. |
81 | */ |
82 | max = arch_scale_cpu_capacity(cpu: cpumask_first(srcp: pd_mask)); |
83 | |
84 | for_each_cpu_and(cpu, pd_mask, cpu_online_mask) |
85 | sum_util += sched_cpu_util(cpu); |
86 | |
87 | return (power * ((sum_util << 10) / max)) >> 10; |
88 | } |
89 | |
90 | static u64 get_pd_power_uw(struct dtpm *dtpm) |
91 | { |
92 | struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
93 | struct em_perf_state *table; |
94 | struct em_perf_domain *pd; |
95 | struct cpumask *pd_mask; |
96 | unsigned long freq; |
97 | u64 power = 0; |
98 | int i; |
99 | |
100 | pd = em_cpu_get(cpu: dtpm_cpu->cpu); |
101 | |
102 | pd_mask = em_span_cpus(pd); |
103 | |
104 | freq = cpufreq_quick_get(cpu: dtpm_cpu->cpu); |
105 | |
106 | rcu_read_lock(); |
107 | table = em_perf_state_from_pd(pd); |
108 | for (i = 0; i < pd->nr_perf_states; i++) { |
109 | |
110 | if (table[i].frequency < freq) |
111 | continue; |
112 | |
113 | power = scale_pd_power_uw(pd_mask, power: table[i].power); |
114 | break; |
115 | } |
116 | rcu_read_unlock(); |
117 | |
118 | return power; |
119 | } |
120 | |
121 | static int update_pd_power_uw(struct dtpm *dtpm) |
122 | { |
123 | struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
124 | struct em_perf_domain *em = em_cpu_get(cpu: dtpm_cpu->cpu); |
125 | struct em_perf_state *table; |
126 | struct cpumask cpus; |
127 | int nr_cpus; |
128 | |
129 | cpumask_and(dstp: &cpus, cpu_online_mask, to_cpumask(em->cpus)); |
130 | nr_cpus = cpumask_weight(srcp: &cpus); |
131 | |
132 | rcu_read_lock(); |
133 | table = em_perf_state_from_pd(pd: em); |
134 | |
135 | dtpm->power_min = table[0].power; |
136 | dtpm->power_min *= nr_cpus; |
137 | |
138 | dtpm->power_max = table[em->nr_perf_states - 1].power; |
139 | dtpm->power_max *= nr_cpus; |
140 | |
141 | rcu_read_unlock(); |
142 | |
143 | return 0; |
144 | } |
145 | |
146 | static void pd_release(struct dtpm *dtpm) |
147 | { |
148 | struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
149 | struct cpufreq_policy *policy; |
150 | |
151 | if (freq_qos_request_active(req: &dtpm_cpu->qos_req)) |
152 | freq_qos_remove_request(req: &dtpm_cpu->qos_req); |
153 | |
154 | policy = cpufreq_cpu_get(cpu: dtpm_cpu->cpu); |
155 | if (policy) { |
156 | for_each_cpu(dtpm_cpu->cpu, policy->related_cpus) |
157 | per_cpu(dtpm_per_cpu, dtpm_cpu->cpu) = NULL; |
158 | |
159 | cpufreq_cpu_put(policy); |
160 | } |
161 | |
162 | kfree(objp: dtpm_cpu); |
163 | } |
164 | |
165 | static struct dtpm_ops dtpm_ops = { |
166 | .set_power_uw = set_pd_power_limit, |
167 | .get_power_uw = get_pd_power_uw, |
168 | .update_power_uw = update_pd_power_uw, |
169 | .release = pd_release, |
170 | }; |
171 | |
172 | static int cpuhp_dtpm_cpu_offline(unsigned int cpu) |
173 | { |
174 | struct dtpm_cpu *dtpm_cpu; |
175 | |
176 | dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); |
177 | if (dtpm_cpu) |
178 | dtpm_update_power(dtpm: &dtpm_cpu->dtpm); |
179 | |
180 | return 0; |
181 | } |
182 | |
183 | static int cpuhp_dtpm_cpu_online(unsigned int cpu) |
184 | { |
185 | struct dtpm_cpu *dtpm_cpu; |
186 | |
187 | dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); |
188 | if (dtpm_cpu) |
189 | return dtpm_update_power(dtpm: &dtpm_cpu->dtpm); |
190 | |
191 | return 0; |
192 | } |
193 | |
194 | static int __dtpm_cpu_setup(int cpu, struct dtpm *parent) |
195 | { |
196 | struct dtpm_cpu *dtpm_cpu; |
197 | struct cpufreq_policy *policy; |
198 | struct em_perf_state *table; |
199 | struct em_perf_domain *pd; |
200 | char name[CPUFREQ_NAME_LEN]; |
201 | int ret = -ENOMEM; |
202 | |
203 | dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); |
204 | if (dtpm_cpu) |
205 | return 0; |
206 | |
207 | policy = cpufreq_cpu_get(cpu); |
208 | if (!policy) |
209 | return 0; |
210 | |
211 | pd = em_cpu_get(cpu); |
212 | if (!pd || em_is_artificial(pd)) { |
213 | ret = -EINVAL; |
214 | goto release_policy; |
215 | } |
216 | |
217 | dtpm_cpu = kzalloc(size: sizeof(*dtpm_cpu), GFP_KERNEL); |
218 | if (!dtpm_cpu) { |
219 | ret = -ENOMEM; |
220 | goto release_policy; |
221 | } |
222 | |
223 | dtpm_init(dtpm: &dtpm_cpu->dtpm, ops: &dtpm_ops); |
224 | dtpm_cpu->cpu = cpu; |
225 | |
226 | for_each_cpu(cpu, policy->related_cpus) |
227 | per_cpu(dtpm_per_cpu, cpu) = dtpm_cpu; |
228 | |
229 | snprintf(buf: name, size: sizeof(name), fmt: "cpu%d-cpufreq" , dtpm_cpu->cpu); |
230 | |
231 | ret = dtpm_register(name, dtpm: &dtpm_cpu->dtpm, parent); |
232 | if (ret) |
233 | goto out_kfree_dtpm_cpu; |
234 | |
235 | rcu_read_lock(); |
236 | table = em_perf_state_from_pd(pd); |
237 | ret = freq_qos_add_request(qos: &policy->constraints, |
238 | req: &dtpm_cpu->qos_req, type: FREQ_QOS_MAX, |
239 | value: table[pd->nr_perf_states - 1].frequency); |
240 | rcu_read_unlock(); |
241 | if (ret < 0) |
242 | goto out_dtpm_unregister; |
243 | |
244 | cpufreq_cpu_put(policy); |
245 | return 0; |
246 | |
247 | out_dtpm_unregister: |
248 | dtpm_unregister(dtpm: &dtpm_cpu->dtpm); |
249 | dtpm_cpu = NULL; |
250 | |
251 | out_kfree_dtpm_cpu: |
252 | for_each_cpu(cpu, policy->related_cpus) |
253 | per_cpu(dtpm_per_cpu, cpu) = NULL; |
254 | kfree(objp: dtpm_cpu); |
255 | |
256 | release_policy: |
257 | cpufreq_cpu_put(policy); |
258 | return ret; |
259 | } |
260 | |
261 | static int dtpm_cpu_setup(struct dtpm *dtpm, struct device_node *np) |
262 | { |
263 | int cpu; |
264 | |
265 | cpu = of_cpu_node_to_id(np); |
266 | if (cpu < 0) |
267 | return 0; |
268 | |
269 | return __dtpm_cpu_setup(cpu, parent: dtpm); |
270 | } |
271 | |
272 | static int dtpm_cpu_init(void) |
273 | { |
274 | int ret; |
275 | |
276 | /* |
277 | * The callbacks at CPU hotplug time are calling |
278 | * dtpm_update_power() which in turns calls update_pd_power(). |
279 | * |
280 | * The function update_pd_power() uses the online mask to |
281 | * figure out the power consumption limits. |
282 | * |
283 | * At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU |
284 | * online mask when the cpuhp_dtpm_cpu_online function is |
285 | * called, but the CPU is still in the online mask for the |
286 | * tear down callback. So the power can not be updated when |
287 | * the CPU is unplugged. |
288 | * |
289 | * At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as |
290 | * above. The CPU online mask is not up to date when the CPU |
291 | * is plugged in. |
292 | * |
293 | * For this reason, we need to call the online and offline |
294 | * callbacks at different moments when the CPU online mask is |
295 | * consistent with the power numbers we want to update. |
296 | */ |
297 | ret = cpuhp_setup_state(state: CPUHP_AP_DTPM_CPU_DEAD, name: "dtpm_cpu:offline" , |
298 | NULL, teardown: cpuhp_dtpm_cpu_offline); |
299 | if (ret < 0) |
300 | return ret; |
301 | |
302 | ret = cpuhp_setup_state(state: CPUHP_AP_ONLINE_DYN, name: "dtpm_cpu:online" , |
303 | startup: cpuhp_dtpm_cpu_online, NULL); |
304 | if (ret < 0) |
305 | return ret; |
306 | |
307 | return 0; |
308 | } |
309 | |
310 | static void dtpm_cpu_exit(void) |
311 | { |
312 | cpuhp_remove_state_nocalls(state: CPUHP_AP_ONLINE_DYN); |
313 | cpuhp_remove_state_nocalls(state: CPUHP_AP_DTPM_CPU_DEAD); |
314 | } |
315 | |
316 | struct dtpm_subsys_ops dtpm_cpu_ops = { |
317 | .name = KBUILD_MODNAME, |
318 | .init = dtpm_cpu_init, |
319 | .exit = dtpm_cpu_exit, |
320 | .setup = dtpm_cpu_setup, |
321 | }; |
322 | |