arm64: dts: qcom: sm8550: add TRNG node
[linux-modified.git] / kernel / power / energy_model.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Energy Model of devices
4  *
5  * Copyright (c) 2018-2021, Arm ltd.
6  * Written by: Quentin Perret, Arm ltd.
7  * Improvements provided by: Lukasz Luba, Arm ltd.
8  */
9
10 #define pr_fmt(fmt) "energy_model: " fmt
11
12 #include <linux/cpu.h>
13 #include <linux/cpufreq.h>
14 #include <linux/cpumask.h>
15 #include <linux/debugfs.h>
16 #include <linux/energy_model.h>
17 #include <linux/sched/topology.h>
18 #include <linux/slab.h>
19
20 /*
21  * Mutex serializing the registrations of performance domains and letting
22  * callbacks defined by drivers sleep.
23  */
24 static DEFINE_MUTEX(em_pd_mutex);
25
26 static bool _is_cpu_device(struct device *dev)
27 {
28         return (dev->bus == &cpu_subsys);
29 }
30
31 #ifdef CONFIG_DEBUG_FS
32 static struct dentry *rootdir;
33
34 static void em_debug_create_ps(struct em_perf_state *ps, struct dentry *pd)
35 {
36         struct dentry *d;
37         char name[24];
38
39         snprintf(name, sizeof(name), "ps:%lu", ps->frequency);
40
41         /* Create per-ps directory */
42         d = debugfs_create_dir(name, pd);
43         debugfs_create_ulong("frequency", 0444, d, &ps->frequency);
44         debugfs_create_ulong("power", 0444, d, &ps->power);
45         debugfs_create_ulong("cost", 0444, d, &ps->cost);
46         debugfs_create_ulong("inefficient", 0444, d, &ps->flags);
47 }
48
49 static int em_debug_cpus_show(struct seq_file *s, void *unused)
50 {
51         seq_printf(s, "%*pbl\n", cpumask_pr_args(to_cpumask(s->private)));
52
53         return 0;
54 }
55 DEFINE_SHOW_ATTRIBUTE(em_debug_cpus);
56
57 static int em_debug_flags_show(struct seq_file *s, void *unused)
58 {
59         struct em_perf_domain *pd = s->private;
60
61         seq_printf(s, "%#lx\n", pd->flags);
62
63         return 0;
64 }
65 DEFINE_SHOW_ATTRIBUTE(em_debug_flags);
66
67 static void em_debug_create_pd(struct device *dev)
68 {
69         struct dentry *d;
70         int i;
71
72         /* Create the directory of the performance domain */
73         d = debugfs_create_dir(dev_name(dev), rootdir);
74
75         if (_is_cpu_device(dev))
76                 debugfs_create_file("cpus", 0444, d, dev->em_pd->cpus,
77                                     &em_debug_cpus_fops);
78
79         debugfs_create_file("flags", 0444, d, dev->em_pd,
80                             &em_debug_flags_fops);
81
82         /* Create a sub-directory for each performance state */
83         for (i = 0; i < dev->em_pd->nr_perf_states; i++)
84                 em_debug_create_ps(&dev->em_pd->table[i], d);
85
86 }
87
88 static void em_debug_remove_pd(struct device *dev)
89 {
90         debugfs_lookup_and_remove(dev_name(dev), rootdir);
91 }
92
93 static int __init em_debug_init(void)
94 {
95         /* Create /sys/kernel/debug/energy_model directory */
96         rootdir = debugfs_create_dir("energy_model", NULL);
97
98         return 0;
99 }
100 fs_initcall(em_debug_init);
101 #else /* CONFIG_DEBUG_FS */
102 static void em_debug_create_pd(struct device *dev) {}
103 static void em_debug_remove_pd(struct device *dev) {}
104 #endif
105
106 static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
107                                 int nr_states, struct em_data_callback *cb,
108                                 unsigned long flags)
109 {
110         unsigned long power, freq, prev_freq = 0, prev_cost = ULONG_MAX;
111         struct em_perf_state *table;
112         int i, ret;
113         u64 fmax;
114
115         table = kcalloc(nr_states, sizeof(*table), GFP_KERNEL);
116         if (!table)
117                 return -ENOMEM;
118
119         /* Build the list of performance states for this performance domain */
120         for (i = 0, freq = 0; i < nr_states; i++, freq++) {
121                 /*
122                  * active_power() is a driver callback which ceils 'freq' to
123                  * lowest performance state of 'dev' above 'freq' and updates
124                  * 'power' and 'freq' accordingly.
125                  */
126                 ret = cb->active_power(dev, &power, &freq);
127                 if (ret) {
128                         dev_err(dev, "EM: invalid perf. state: %d\n",
129                                 ret);
130                         goto free_ps_table;
131                 }
132
133                 /*
134                  * We expect the driver callback to increase the frequency for
135                  * higher performance states.
136                  */
137                 if (freq <= prev_freq) {
138                         dev_err(dev, "EM: non-increasing freq: %lu\n",
139                                 freq);
140                         goto free_ps_table;
141                 }
142
143                 /*
144                  * The power returned by active_state() is expected to be
145                  * positive and be in range.
146                  */
147                 if (!power || power > EM_MAX_POWER) {
148                         dev_err(dev, "EM: invalid power: %lu\n",
149                                 power);
150                         goto free_ps_table;
151                 }
152
153                 table[i].power = power;
154                 table[i].frequency = prev_freq = freq;
155         }
156
157         /* Compute the cost of each performance state. */
158         fmax = (u64) table[nr_states - 1].frequency;
159         for (i = nr_states - 1; i >= 0; i--) {
160                 unsigned long power_res, cost;
161
162                 if (flags & EM_PERF_DOMAIN_ARTIFICIAL) {
163                         ret = cb->get_cost(dev, table[i].frequency, &cost);
164                         if (ret || !cost || cost > EM_MAX_POWER) {
165                                 dev_err(dev, "EM: invalid cost %lu %d\n",
166                                         cost, ret);
167                                 goto free_ps_table;
168                         }
169                 } else {
170                         power_res = table[i].power;
171                         cost = div64_u64(fmax * power_res, table[i].frequency);
172                 }
173
174                 table[i].cost = cost;
175
176                 if (table[i].cost >= prev_cost) {
177                         table[i].flags = EM_PERF_STATE_INEFFICIENT;
178                         dev_dbg(dev, "EM: OPP:%lu is inefficient\n",
179                                 table[i].frequency);
180                 } else {
181                         prev_cost = table[i].cost;
182                 }
183         }
184
185         pd->table = table;
186         pd->nr_perf_states = nr_states;
187
188         return 0;
189
190 free_ps_table:
191         kfree(table);
192         return -EINVAL;
193 }
194
195 static int em_create_pd(struct device *dev, int nr_states,
196                         struct em_data_callback *cb, cpumask_t *cpus,
197                         unsigned long flags)
198 {
199         struct em_perf_domain *pd;
200         struct device *cpu_dev;
201         int cpu, ret, num_cpus;
202
203         if (_is_cpu_device(dev)) {
204                 num_cpus = cpumask_weight(cpus);
205
206                 /* Prevent max possible energy calculation to not overflow */
207                 if (num_cpus > EM_MAX_NUM_CPUS) {
208                         dev_err(dev, "EM: too many CPUs, overflow possible\n");
209                         return -EINVAL;
210                 }
211
212                 pd = kzalloc(sizeof(*pd) + cpumask_size(), GFP_KERNEL);
213                 if (!pd)
214                         return -ENOMEM;
215
216                 cpumask_copy(em_span_cpus(pd), cpus);
217         } else {
218                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
219                 if (!pd)
220                         return -ENOMEM;
221         }
222
223         ret = em_create_perf_table(dev, pd, nr_states, cb, flags);
224         if (ret) {
225                 kfree(pd);
226                 return ret;
227         }
228
229         if (_is_cpu_device(dev))
230                 for_each_cpu(cpu, cpus) {
231                         cpu_dev = get_cpu_device(cpu);
232                         cpu_dev->em_pd = pd;
233                 }
234
235         dev->em_pd = pd;
236
237         return 0;
238 }
239
240 static void em_cpufreq_update_efficiencies(struct device *dev)
241 {
242         struct em_perf_domain *pd = dev->em_pd;
243         struct em_perf_state *table;
244         struct cpufreq_policy *policy;
245         int found = 0;
246         int i;
247
248         if (!_is_cpu_device(dev) || !pd)
249                 return;
250
251         policy = cpufreq_cpu_get(cpumask_first(em_span_cpus(pd)));
252         if (!policy) {
253                 dev_warn(dev, "EM: Access to CPUFreq policy failed");
254                 return;
255         }
256
257         table = pd->table;
258
259         for (i = 0; i < pd->nr_perf_states; i++) {
260                 if (!(table[i].flags & EM_PERF_STATE_INEFFICIENT))
261                         continue;
262
263                 if (!cpufreq_table_set_inefficient(policy, table[i].frequency))
264                         found++;
265         }
266
267         cpufreq_cpu_put(policy);
268
269         if (!found)
270                 return;
271
272         /*
273          * Efficiencies have been installed in CPUFreq, inefficient frequencies
274          * will be skipped. The EM can do the same.
275          */
276         pd->flags |= EM_PERF_DOMAIN_SKIP_INEFFICIENCIES;
277 }
278
279 /**
280  * em_pd_get() - Return the performance domain for a device
281  * @dev : Device to find the performance domain for
282  *
283  * Returns the performance domain to which @dev belongs, or NULL if it doesn't
284  * exist.
285  */
286 struct em_perf_domain *em_pd_get(struct device *dev)
287 {
288         if (IS_ERR_OR_NULL(dev))
289                 return NULL;
290
291         return dev->em_pd;
292 }
293 EXPORT_SYMBOL_GPL(em_pd_get);
294
295 /**
296  * em_cpu_get() - Return the performance domain for a CPU
297  * @cpu : CPU to find the performance domain for
298  *
299  * Returns the performance domain to which @cpu belongs, or NULL if it doesn't
300  * exist.
301  */
302 struct em_perf_domain *em_cpu_get(int cpu)
303 {
304         struct device *cpu_dev;
305
306         cpu_dev = get_cpu_device(cpu);
307         if (!cpu_dev)
308                 return NULL;
309
310         return em_pd_get(cpu_dev);
311 }
312 EXPORT_SYMBOL_GPL(em_cpu_get);
313
314 /**
315  * em_dev_register_perf_domain() - Register the Energy Model (EM) for a device
316  * @dev         : Device for which the EM is to register
317  * @nr_states   : Number of performance states to register
318  * @cb          : Callback functions providing the data of the Energy Model
319  * @cpus        : Pointer to cpumask_t, which in case of a CPU device is
320  *              obligatory. It can be taken from i.e. 'policy->cpus'. For other
321  *              type of devices this should be set to NULL.
322  * @microwatts  : Flag indicating that the power values are in micro-Watts or
323  *              in some other scale. It must be set properly.
324  *
325  * Create Energy Model tables for a performance domain using the callbacks
326  * defined in cb.
327  *
328  * The @microwatts is important to set with correct value. Some kernel
329  * sub-systems might rely on this flag and check if all devices in the EM are
330  * using the same scale.
331  *
332  * If multiple clients register the same performance domain, all but the first
333  * registration will be ignored.
334  *
335  * Return 0 on success
336  */
337 int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
338                                 struct em_data_callback *cb, cpumask_t *cpus,
339                                 bool microwatts)
340 {
341         unsigned long cap, prev_cap = 0;
342         unsigned long flags = 0;
343         int cpu, ret;
344
345         if (!dev || !nr_states || !cb)
346                 return -EINVAL;
347
348         /*
349          * Use a mutex to serialize the registration of performance domains and
350          * let the driver-defined callback functions sleep.
351          */
352         mutex_lock(&em_pd_mutex);
353
354         if (dev->em_pd) {
355                 ret = -EEXIST;
356                 goto unlock;
357         }
358
359         if (_is_cpu_device(dev)) {
360                 if (!cpus) {
361                         dev_err(dev, "EM: invalid CPU mask\n");
362                         ret = -EINVAL;
363                         goto unlock;
364                 }
365
366                 for_each_cpu(cpu, cpus) {
367                         if (em_cpu_get(cpu)) {
368                                 dev_err(dev, "EM: exists for CPU%d\n", cpu);
369                                 ret = -EEXIST;
370                                 goto unlock;
371                         }
372                         /*
373                          * All CPUs of a domain must have the same
374                          * micro-architecture since they all share the same
375                          * table.
376                          */
377                         cap = arch_scale_cpu_capacity(cpu);
378                         if (prev_cap && prev_cap != cap) {
379                                 dev_err(dev, "EM: CPUs of %*pbl must have the same capacity\n",
380                                         cpumask_pr_args(cpus));
381
382                                 ret = -EINVAL;
383                                 goto unlock;
384                         }
385                         prev_cap = cap;
386                 }
387         }
388
389         if (microwatts)
390                 flags |= EM_PERF_DOMAIN_MICROWATTS;
391         else if (cb->get_cost)
392                 flags |= EM_PERF_DOMAIN_ARTIFICIAL;
393
394         ret = em_create_pd(dev, nr_states, cb, cpus, flags);
395         if (ret)
396                 goto unlock;
397
398         dev->em_pd->flags |= flags;
399
400         em_cpufreq_update_efficiencies(dev);
401
402         em_debug_create_pd(dev);
403         dev_info(dev, "EM: created perf domain\n");
404
405 unlock:
406         mutex_unlock(&em_pd_mutex);
407         return ret;
408 }
409 EXPORT_SYMBOL_GPL(em_dev_register_perf_domain);
410
411 /**
412  * em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device
413  * @dev         : Device for which the EM is registered
414  *
415  * Unregister the EM for the specified @dev (but not a CPU device).
416  */
417 void em_dev_unregister_perf_domain(struct device *dev)
418 {
419         if (IS_ERR_OR_NULL(dev) || !dev->em_pd)
420                 return;
421
422         if (_is_cpu_device(dev))
423                 return;
424
425         /*
426          * The mutex separates all register/unregister requests and protects
427          * from potential clean-up/setup issues in the debugfs directories.
428          * The debugfs directory name is the same as device's name.
429          */
430         mutex_lock(&em_pd_mutex);
431         em_debug_remove_pd(dev);
432
433         kfree(dev->em_pd->table);
434         kfree(dev->em_pd);
435         dev->em_pd = NULL;
436         mutex_unlock(&em_pd_mutex);
437 }
438 EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);