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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Energy Model of devices
4 *
5 * Copyright (c) 2018-2020, 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/cpumask.h>
14#include <linux/debugfs.h>
15#include <linux/energy_model.h>
16#include <linux/sched/topology.h>
17#include <linux/slab.h>
18
19/*
20 * Mutex serializing the registrations of performance domains and letting
21 * callbacks defined by drivers sleep.
22 */
23static DEFINE_MUTEX(em_pd_mutex);
24
25static bool _is_cpu_device(struct device *dev)
26{
27 return (dev->bus == &cpu_subsys);
28}
29
30#ifdef CONFIG_DEBUG_FS
31static struct dentry *rootdir;
32
33static void em_debug_create_ps(struct em_perf_state *ps, struct dentry *pd)
34{
35 struct dentry *d;
36 char name[24];
37
38 snprintf(name, sizeof(name), "ps:%lu", ps->frequency);
39
40 /* Create per-ps directory */
41 d = debugfs_create_dir(name, pd);
42 debugfs_create_ulong("frequency", 0444, d, &ps->frequency);
43 debugfs_create_ulong("power", 0444, d, &ps->power);
44 debugfs_create_ulong("cost", 0444, d, &ps->cost);
45}
46
47static int em_debug_cpus_show(struct seq_file *s, void *unused)
48{
49 seq_printf(s, "%*pbl\n", cpumask_pr_args(to_cpumask(s->private)));
50
51 return 0;
52}
53DEFINE_SHOW_ATTRIBUTE(em_debug_cpus);
54
55static void em_debug_create_pd(struct device *dev)
56{
57 struct dentry *d;
58 int i;
59
60 /* Create the directory of the performance domain */
61 d = debugfs_create_dir(dev_name(dev), rootdir);
62
63 if (_is_cpu_device(dev))
64 debugfs_create_file("cpus", 0444, d, dev->em_pd->cpus,
65 &em_debug_cpus_fops);
66
67 /* Create a sub-directory for each performance state */
68 for (i = 0; i < dev->em_pd->nr_perf_states; i++)
69 em_debug_create_ps(&dev->em_pd->table[i], d);
70
71}
72
73static void em_debug_remove_pd(struct device *dev)
74{
75 struct dentry *debug_dir;
76
77 debug_dir = debugfs_lookup(dev_name(dev), rootdir);
78 debugfs_remove_recursive(debug_dir);
79}
80
81static int __init em_debug_init(void)
82{
83 /* Create /sys/kernel/debug/energy_model directory */
84 rootdir = debugfs_create_dir("energy_model", NULL);
85
86 return 0;
87}
88core_initcall(em_debug_init);
89#else /* CONFIG_DEBUG_FS */
90static void em_debug_create_pd(struct device *dev) {}
91static void em_debug_remove_pd(struct device *dev) {}
92#endif
93
94static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
95 int nr_states, struct em_data_callback *cb)
96{
97 unsigned long opp_eff, prev_opp_eff = ULONG_MAX;
98 unsigned long power, freq, prev_freq = 0;
99 struct em_perf_state *table;
100 int i, ret;
101 u64 fmax;
102
103 table = kcalloc(nr_states, sizeof(*table), GFP_KERNEL);
104 if (!table)
105 return -ENOMEM;
106
107 /* Build the list of performance states for this performance domain */
108 for (i = 0, freq = 0; i < nr_states; i++, freq++) {
109 /*
110 * active_power() is a driver callback which ceils 'freq' to
111 * lowest performance state of 'dev' above 'freq' and updates
112 * 'power' and 'freq' accordingly.
113 */
114 ret = cb->active_power(&power, &freq, dev);
115 if (ret) {
116 dev_err(dev, "EM: invalid perf. state: %d\n",
117 ret);
118 goto free_ps_table;
119 }
120
121 /*
122 * We expect the driver callback to increase the frequency for
123 * higher performance states.
124 */
125 if (freq <= prev_freq) {
126 dev_err(dev, "EM: non-increasing freq: %lu\n",
127 freq);
128 goto free_ps_table;
129 }
130
131 /*
132 * The power returned by active_state() is expected to be
133 * positive, in milli-watts and to fit into 16 bits.
134 */
135 if (!power || power > EM_MAX_POWER) {
136 dev_err(dev, "EM: invalid power: %lu\n",
137 power);
138 goto free_ps_table;
139 }
140
141 table[i].power = power;
142 table[i].frequency = prev_freq = freq;
143
144 /*
145 * The hertz/watts efficiency ratio should decrease as the
146 * frequency grows on sane platforms. But this isn't always
147 * true in practice so warn the user if a higher OPP is more
148 * power efficient than a lower one.
149 */
150 opp_eff = freq / power;
151 if (opp_eff >= prev_opp_eff)
152 dev_dbg(dev, "EM: hertz/watts ratio non-monotonically decreasing: em_perf_state %d >= em_perf_state%d\n",
153 i, i - 1);
154 prev_opp_eff = opp_eff;
155 }
156
157 /* Compute the cost of each performance state. */
158 fmax = (u64) table[nr_states - 1].frequency;
159 for (i = 0; i < nr_states; i++) {
160 table[i].cost = div64_u64(fmax * table[i].power,
161 table[i].frequency);
162 }
163
164 pd->table = table;
165 pd->nr_perf_states = nr_states;
166
167 return 0;
168
169free_ps_table:
170 kfree(table);
171 return -EINVAL;
172}
173
174static int em_create_pd(struct device *dev, int nr_states,
175 struct em_data_callback *cb, cpumask_t *cpus)
176{
177 struct em_perf_domain *pd;
178 struct device *cpu_dev;
179 int cpu, ret;
180
181 if (_is_cpu_device(dev)) {
182 pd = kzalloc(sizeof(*pd) + cpumask_size(), GFP_KERNEL);
183 if (!pd)
184 return -ENOMEM;
185
186 cpumask_copy(em_span_cpus(pd), cpus);
187 } else {
188 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
189 if (!pd)
190 return -ENOMEM;
191 }
192
193 ret = em_create_perf_table(dev, pd, nr_states, cb);
194 if (ret) {
195 kfree(pd);
196 return ret;
197 }
198
199 if (_is_cpu_device(dev))
200 for_each_cpu(cpu, cpus) {
201 cpu_dev = get_cpu_device(cpu);
202 cpu_dev->em_pd = pd;
203 }
204
205 dev->em_pd = pd;
206
207 return 0;
208}
209
210/**
211 * em_pd_get() - Return the performance domain for a device
212 * @dev : Device to find the performance domain for
213 *
214 * Returns the performance domain to which @dev belongs, or NULL if it doesn't
215 * exist.
216 */
217struct em_perf_domain *em_pd_get(struct device *dev)
218{
219 if (IS_ERR_OR_NULL(dev))
220 return NULL;
221
222 return dev->em_pd;
223}
224EXPORT_SYMBOL_GPL(em_pd_get);
225
226/**
227 * em_cpu_get() - Return the performance domain for a CPU
228 * @cpu : CPU to find the performance domain for
229 *
230 * Returns the performance domain to which @cpu belongs, or NULL if it doesn't
231 * exist.
232 */
233struct em_perf_domain *em_cpu_get(int cpu)
234{
235 struct device *cpu_dev;
236
237 cpu_dev = get_cpu_device(cpu);
238 if (!cpu_dev)
239 return NULL;
240
241 return em_pd_get(cpu_dev);
242}
243EXPORT_SYMBOL_GPL(em_cpu_get);
244
245/**
246 * em_dev_register_perf_domain() - Register the Energy Model (EM) for a device
247 * @dev : Device for which the EM is to register
248 * @nr_states : Number of performance states to register
249 * @cb : Callback functions providing the data of the Energy Model
250 * @cpus : Pointer to cpumask_t, which in case of a CPU device is
251 * obligatory. It can be taken from i.e. 'policy->cpus'. For other
252 * type of devices this should be set to NULL.
253 *
254 * Create Energy Model tables for a performance domain using the callbacks
255 * defined in cb.
256 *
257 * If multiple clients register the same performance domain, all but the first
258 * registration will be ignored.
259 *
260 * Return 0 on success
261 */
262int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
263 struct em_data_callback *cb, cpumask_t *cpus)
264{
265 unsigned long cap, prev_cap = 0;
266 int cpu, ret;
267
268 if (!dev || !nr_states || !cb)
269 return -EINVAL;
270
271 /*
272 * Use a mutex to serialize the registration of performance domains and
273 * let the driver-defined callback functions sleep.
274 */
275 mutex_lock(&em_pd_mutex);
276
277 if (dev->em_pd) {
278 ret = -EEXIST;
279 goto unlock;
280 }
281
282 if (_is_cpu_device(dev)) {
283 if (!cpus) {
284 dev_err(dev, "EM: invalid CPU mask\n");
285 ret = -EINVAL;
286 goto unlock;
287 }
288
289 for_each_cpu(cpu, cpus) {
290 if (em_cpu_get(cpu)) {
291 dev_err(dev, "EM: exists for CPU%d\n", cpu);
292 ret = -EEXIST;
293 goto unlock;
294 }
295 /*
296 * All CPUs of a domain must have the same
297 * micro-architecture since they all share the same
298 * table.
299 */
300 cap = arch_scale_cpu_capacity(cpu);
301 if (prev_cap && prev_cap != cap) {
302 dev_err(dev, "EM: CPUs of %*pbl must have the same capacity\n",
303 cpumask_pr_args(cpus));
304
305 ret = -EINVAL;
306 goto unlock;
307 }
308 prev_cap = cap;
309 }
310 }
311
312 ret = em_create_pd(dev, nr_states, cb, cpus);
313 if (ret)
314 goto unlock;
315
316 em_debug_create_pd(dev);
317 dev_info(dev, "EM: created perf domain\n");
318
319unlock:
320 mutex_unlock(&em_pd_mutex);
321 return ret;
322}
323EXPORT_SYMBOL_GPL(em_dev_register_perf_domain);
324
325/**
326 * em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device
327 * @dev : Device for which the EM is registered
328 *
329 * Unregister the EM for the specified @dev (but not a CPU device).
330 */
331void em_dev_unregister_perf_domain(struct device *dev)
332{
333 if (IS_ERR_OR_NULL(dev) || !dev->em_pd)
334 return;
335
336 if (_is_cpu_device(dev))
337 return;
338
339 /*
340 * The mutex separates all register/unregister requests and protects
341 * from potential clean-up/setup issues in the debugfs directories.
342 * The debugfs directory name is the same as device's name.
343 */
344 mutex_lock(&em_pd_mutex);
345 em_debug_remove_pd(dev);
346
347 kfree(dev->em_pd->table);
348 kfree(dev->em_pd);
349 dev->em_pd = NULL;
350 mutex_unlock(&em_pd_mutex);
351}
352EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);
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 */
24static DEFINE_MUTEX(em_pd_mutex);
25
26static void em_cpufreq_update_efficiencies(struct device *dev,
27 struct em_perf_state *table);
28static void em_check_capacity_update(void);
29static void em_update_workfn(struct work_struct *work);
30static DECLARE_DELAYED_WORK(em_update_work, em_update_workfn);
31
32static bool _is_cpu_device(struct device *dev)
33{
34 return (dev->bus == &cpu_subsys);
35}
36
37#ifdef CONFIG_DEBUG_FS
38static struct dentry *rootdir;
39
40struct em_dbg_info {
41 struct em_perf_domain *pd;
42 int ps_id;
43};
44
45#define DEFINE_EM_DBG_SHOW(name, fname) \
46static int em_debug_##fname##_show(struct seq_file *s, void *unused) \
47{ \
48 struct em_dbg_info *em_dbg = s->private; \
49 struct em_perf_state *table; \
50 unsigned long val; \
51 \
52 rcu_read_lock(); \
53 table = em_perf_state_from_pd(em_dbg->pd); \
54 val = table[em_dbg->ps_id].name; \
55 rcu_read_unlock(); \
56 \
57 seq_printf(s, "%lu\n", val); \
58 return 0; \
59} \
60DEFINE_SHOW_ATTRIBUTE(em_debug_##fname)
61
62DEFINE_EM_DBG_SHOW(frequency, frequency);
63DEFINE_EM_DBG_SHOW(power, power);
64DEFINE_EM_DBG_SHOW(cost, cost);
65DEFINE_EM_DBG_SHOW(performance, performance);
66DEFINE_EM_DBG_SHOW(flags, inefficiency);
67
68static void em_debug_create_ps(struct em_perf_domain *em_pd,
69 struct em_dbg_info *em_dbg, int i,
70 struct dentry *pd)
71{
72 struct em_perf_state *table;
73 unsigned long freq;
74 struct dentry *d;
75 char name[24];
76
77 em_dbg[i].pd = em_pd;
78 em_dbg[i].ps_id = i;
79
80 rcu_read_lock();
81 table = em_perf_state_from_pd(em_pd);
82 freq = table[i].frequency;
83 rcu_read_unlock();
84
85 snprintf(name, sizeof(name), "ps:%lu", freq);
86
87 /* Create per-ps directory */
88 d = debugfs_create_dir(name, pd);
89 debugfs_create_file("frequency", 0444, d, &em_dbg[i],
90 &em_debug_frequency_fops);
91 debugfs_create_file("power", 0444, d, &em_dbg[i],
92 &em_debug_power_fops);
93 debugfs_create_file("cost", 0444, d, &em_dbg[i],
94 &em_debug_cost_fops);
95 debugfs_create_file("performance", 0444, d, &em_dbg[i],
96 &em_debug_performance_fops);
97 debugfs_create_file("inefficient", 0444, d, &em_dbg[i],
98 &em_debug_inefficiency_fops);
99}
100
101static int em_debug_cpus_show(struct seq_file *s, void *unused)
102{
103 seq_printf(s, "%*pbl\n", cpumask_pr_args(to_cpumask(s->private)));
104
105 return 0;
106}
107DEFINE_SHOW_ATTRIBUTE(em_debug_cpus);
108
109static int em_debug_flags_show(struct seq_file *s, void *unused)
110{
111 struct em_perf_domain *pd = s->private;
112
113 seq_printf(s, "%#lx\n", pd->flags);
114
115 return 0;
116}
117DEFINE_SHOW_ATTRIBUTE(em_debug_flags);
118
119static void em_debug_create_pd(struct device *dev)
120{
121 struct em_dbg_info *em_dbg;
122 struct dentry *d;
123 int i;
124
125 /* Create the directory of the performance domain */
126 d = debugfs_create_dir(dev_name(dev), rootdir);
127
128 if (_is_cpu_device(dev))
129 debugfs_create_file("cpus", 0444, d, dev->em_pd->cpus,
130 &em_debug_cpus_fops);
131
132 debugfs_create_file("flags", 0444, d, dev->em_pd,
133 &em_debug_flags_fops);
134
135 em_dbg = devm_kcalloc(dev, dev->em_pd->nr_perf_states,
136 sizeof(*em_dbg), GFP_KERNEL);
137 if (!em_dbg)
138 return;
139
140 /* Create a sub-directory for each performance state */
141 for (i = 0; i < dev->em_pd->nr_perf_states; i++)
142 em_debug_create_ps(dev->em_pd, em_dbg, i, d);
143
144}
145
146static void em_debug_remove_pd(struct device *dev)
147{
148 debugfs_lookup_and_remove(dev_name(dev), rootdir);
149}
150
151static int __init em_debug_init(void)
152{
153 /* Create /sys/kernel/debug/energy_model directory */
154 rootdir = debugfs_create_dir("energy_model", NULL);
155
156 return 0;
157}
158fs_initcall(em_debug_init);
159#else /* CONFIG_DEBUG_FS */
160static void em_debug_create_pd(struct device *dev) {}
161static void em_debug_remove_pd(struct device *dev) {}
162#endif
163
164static void em_destroy_table_rcu(struct rcu_head *rp)
165{
166 struct em_perf_table __rcu *table;
167
168 table = container_of(rp, struct em_perf_table, rcu);
169 kfree(table);
170}
171
172static void em_release_table_kref(struct kref *kref)
173{
174 struct em_perf_table __rcu *table;
175
176 /* It was the last owner of this table so we can free */
177 table = container_of(kref, struct em_perf_table, kref);
178
179 call_rcu(&table->rcu, em_destroy_table_rcu);
180}
181
182/**
183 * em_table_free() - Handles safe free of the EM table when needed
184 * @table : EM table which is going to be freed
185 *
186 * No return values.
187 */
188void em_table_free(struct em_perf_table __rcu *table)
189{
190 kref_put(&table->kref, em_release_table_kref);
191}
192
193/**
194 * em_table_alloc() - Allocate a new EM table
195 * @pd : EM performance domain for which this must be done
196 *
197 * Allocate a new EM table and initialize its kref to indicate that it
198 * has a user.
199 * Returns allocated table or NULL.
200 */
201struct em_perf_table __rcu *em_table_alloc(struct em_perf_domain *pd)
202{
203 struct em_perf_table __rcu *table;
204 int table_size;
205
206 table_size = sizeof(struct em_perf_state) * pd->nr_perf_states;
207
208 table = kzalloc(sizeof(*table) + table_size, GFP_KERNEL);
209 if (!table)
210 return NULL;
211
212 kref_init(&table->kref);
213
214 return table;
215}
216
217static void em_init_performance(struct device *dev, struct em_perf_domain *pd,
218 struct em_perf_state *table, int nr_states)
219{
220 u64 fmax, max_cap;
221 int i, cpu;
222
223 /* This is needed only for CPUs and EAS skip other devices */
224 if (!_is_cpu_device(dev))
225 return;
226
227 cpu = cpumask_first(em_span_cpus(pd));
228
229 /*
230 * Calculate the performance value for each frequency with
231 * linear relationship. The final CPU capacity might not be ready at
232 * boot time, but the EM will be updated a bit later with correct one.
233 */
234 fmax = (u64) table[nr_states - 1].frequency;
235 max_cap = (u64) arch_scale_cpu_capacity(cpu);
236 for (i = 0; i < nr_states; i++)
237 table[i].performance = div64_u64(max_cap * table[i].frequency,
238 fmax);
239}
240
241static int em_compute_costs(struct device *dev, struct em_perf_state *table,
242 struct em_data_callback *cb, int nr_states,
243 unsigned long flags)
244{
245 unsigned long prev_cost = ULONG_MAX;
246 int i, ret;
247
248 /* Compute the cost of each performance state. */
249 for (i = nr_states - 1; i >= 0; i--) {
250 unsigned long power_res, cost;
251
252 if ((flags & EM_PERF_DOMAIN_ARTIFICIAL) && cb->get_cost) {
253 ret = cb->get_cost(dev, table[i].frequency, &cost);
254 if (ret || !cost || cost > EM_MAX_POWER) {
255 dev_err(dev, "EM: invalid cost %lu %d\n",
256 cost, ret);
257 return -EINVAL;
258 }
259 } else {
260 /* increase resolution of 'cost' precision */
261 power_res = table[i].power * 10;
262 cost = power_res / table[i].performance;
263 }
264
265 table[i].cost = cost;
266
267 if (table[i].cost >= prev_cost) {
268 table[i].flags = EM_PERF_STATE_INEFFICIENT;
269 dev_dbg(dev, "EM: OPP:%lu is inefficient\n",
270 table[i].frequency);
271 } else {
272 prev_cost = table[i].cost;
273 }
274 }
275
276 return 0;
277}
278
279/**
280 * em_dev_compute_costs() - Calculate cost values for new runtime EM table
281 * @dev : Device for which the EM table is to be updated
282 * @table : The new EM table that is going to get the costs calculated
283 * @nr_states : Number of performance states
284 *
285 * Calculate the em_perf_state::cost values for new runtime EM table. The
286 * values are used for EAS during task placement. It also calculates and sets
287 * the efficiency flag for each performance state. When the function finish
288 * successfully the EM table is ready to be updated and used by EAS.
289 *
290 * Return 0 on success or a proper error in case of failure.
291 */
292int em_dev_compute_costs(struct device *dev, struct em_perf_state *table,
293 int nr_states)
294{
295 return em_compute_costs(dev, table, NULL, nr_states, 0);
296}
297
298/**
299 * em_dev_update_perf_domain() - Update runtime EM table for a device
300 * @dev : Device for which the EM is to be updated
301 * @new_table : The new EM table that is going to be used from now
302 *
303 * Update EM runtime modifiable table for the @dev using the provided @table.
304 *
305 * This function uses a mutex to serialize writers, so it must not be called
306 * from a non-sleeping context.
307 *
308 * Return 0 on success or an error code on failure.
309 */
310int em_dev_update_perf_domain(struct device *dev,
311 struct em_perf_table __rcu *new_table)
312{
313 struct em_perf_table __rcu *old_table;
314 struct em_perf_domain *pd;
315
316 if (!dev)
317 return -EINVAL;
318
319 /* Serialize update/unregister or concurrent updates */
320 mutex_lock(&em_pd_mutex);
321
322 if (!dev->em_pd) {
323 mutex_unlock(&em_pd_mutex);
324 return -EINVAL;
325 }
326 pd = dev->em_pd;
327
328 kref_get(&new_table->kref);
329
330 old_table = pd->em_table;
331 rcu_assign_pointer(pd->em_table, new_table);
332
333 em_cpufreq_update_efficiencies(dev, new_table->state);
334
335 em_table_free(old_table);
336
337 mutex_unlock(&em_pd_mutex);
338 return 0;
339}
340EXPORT_SYMBOL_GPL(em_dev_update_perf_domain);
341
342static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
343 struct em_perf_state *table,
344 struct em_data_callback *cb,
345 unsigned long flags)
346{
347 unsigned long power, freq, prev_freq = 0;
348 int nr_states = pd->nr_perf_states;
349 int i, ret;
350
351 /* Build the list of performance states for this performance domain */
352 for (i = 0, freq = 0; i < nr_states; i++, freq++) {
353 /*
354 * active_power() is a driver callback which ceils 'freq' to
355 * lowest performance state of 'dev' above 'freq' and updates
356 * 'power' and 'freq' accordingly.
357 */
358 ret = cb->active_power(dev, &power, &freq);
359 if (ret) {
360 dev_err(dev, "EM: invalid perf. state: %d\n",
361 ret);
362 return -EINVAL;
363 }
364
365 /*
366 * We expect the driver callback to increase the frequency for
367 * higher performance states.
368 */
369 if (freq <= prev_freq) {
370 dev_err(dev, "EM: non-increasing freq: %lu\n",
371 freq);
372 return -EINVAL;
373 }
374
375 /*
376 * The power returned by active_state() is expected to be
377 * positive and be in range.
378 */
379 if (!power || power > EM_MAX_POWER) {
380 dev_err(dev, "EM: invalid power: %lu\n",
381 power);
382 return -EINVAL;
383 }
384
385 table[i].power = power;
386 table[i].frequency = prev_freq = freq;
387 }
388
389 em_init_performance(dev, pd, table, nr_states);
390
391 ret = em_compute_costs(dev, table, cb, nr_states, flags);
392 if (ret)
393 return -EINVAL;
394
395 return 0;
396}
397
398static int em_create_pd(struct device *dev, int nr_states,
399 struct em_data_callback *cb, cpumask_t *cpus,
400 unsigned long flags)
401{
402 struct em_perf_table __rcu *em_table;
403 struct em_perf_domain *pd;
404 struct device *cpu_dev;
405 int cpu, ret, num_cpus;
406
407 if (_is_cpu_device(dev)) {
408 num_cpus = cpumask_weight(cpus);
409
410 /* Prevent max possible energy calculation to not overflow */
411 if (num_cpus > EM_MAX_NUM_CPUS) {
412 dev_err(dev, "EM: too many CPUs, overflow possible\n");
413 return -EINVAL;
414 }
415
416 pd = kzalloc(sizeof(*pd) + cpumask_size(), GFP_KERNEL);
417 if (!pd)
418 return -ENOMEM;
419
420 cpumask_copy(em_span_cpus(pd), cpus);
421 } else {
422 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
423 if (!pd)
424 return -ENOMEM;
425 }
426
427 pd->nr_perf_states = nr_states;
428
429 em_table = em_table_alloc(pd);
430 if (!em_table)
431 goto free_pd;
432
433 ret = em_create_perf_table(dev, pd, em_table->state, cb, flags);
434 if (ret)
435 goto free_pd_table;
436
437 rcu_assign_pointer(pd->em_table, em_table);
438
439 if (_is_cpu_device(dev))
440 for_each_cpu(cpu, cpus) {
441 cpu_dev = get_cpu_device(cpu);
442 cpu_dev->em_pd = pd;
443 }
444
445 dev->em_pd = pd;
446
447 return 0;
448
449free_pd_table:
450 kfree(em_table);
451free_pd:
452 kfree(pd);
453 return -EINVAL;
454}
455
456static void
457em_cpufreq_update_efficiencies(struct device *dev, struct em_perf_state *table)
458{
459 struct em_perf_domain *pd = dev->em_pd;
460 struct cpufreq_policy *policy;
461 int found = 0;
462 int i, cpu;
463
464 if (!_is_cpu_device(dev))
465 return;
466
467 /* Try to get a CPU which is active and in this PD */
468 cpu = cpumask_first_and(em_span_cpus(pd), cpu_active_mask);
469 if (cpu >= nr_cpu_ids) {
470 dev_warn(dev, "EM: No online CPU for CPUFreq policy\n");
471 return;
472 }
473
474 policy = cpufreq_cpu_get(cpu);
475 if (!policy) {
476 dev_warn(dev, "EM: Access to CPUFreq policy failed\n");
477 return;
478 }
479
480 for (i = 0; i < pd->nr_perf_states; i++) {
481 if (!(table[i].flags & EM_PERF_STATE_INEFFICIENT))
482 continue;
483
484 if (!cpufreq_table_set_inefficient(policy, table[i].frequency))
485 found++;
486 }
487
488 cpufreq_cpu_put(policy);
489
490 if (!found)
491 return;
492
493 /*
494 * Efficiencies have been installed in CPUFreq, inefficient frequencies
495 * will be skipped. The EM can do the same.
496 */
497 pd->flags |= EM_PERF_DOMAIN_SKIP_INEFFICIENCIES;
498}
499
500/**
501 * em_pd_get() - Return the performance domain for a device
502 * @dev : Device to find the performance domain for
503 *
504 * Returns the performance domain to which @dev belongs, or NULL if it doesn't
505 * exist.
506 */
507struct em_perf_domain *em_pd_get(struct device *dev)
508{
509 if (IS_ERR_OR_NULL(dev))
510 return NULL;
511
512 return dev->em_pd;
513}
514EXPORT_SYMBOL_GPL(em_pd_get);
515
516/**
517 * em_cpu_get() - Return the performance domain for a CPU
518 * @cpu : CPU to find the performance domain for
519 *
520 * Returns the performance domain to which @cpu belongs, or NULL if it doesn't
521 * exist.
522 */
523struct em_perf_domain *em_cpu_get(int cpu)
524{
525 struct device *cpu_dev;
526
527 cpu_dev = get_cpu_device(cpu);
528 if (!cpu_dev)
529 return NULL;
530
531 return em_pd_get(cpu_dev);
532}
533EXPORT_SYMBOL_GPL(em_cpu_get);
534
535/**
536 * em_dev_register_perf_domain() - Register the Energy Model (EM) for a device
537 * @dev : Device for which the EM is to register
538 * @nr_states : Number of performance states to register
539 * @cb : Callback functions providing the data of the Energy Model
540 * @cpus : Pointer to cpumask_t, which in case of a CPU device is
541 * obligatory. It can be taken from i.e. 'policy->cpus'. For other
542 * type of devices this should be set to NULL.
543 * @microwatts : Flag indicating that the power values are in micro-Watts or
544 * in some other scale. It must be set properly.
545 *
546 * Create Energy Model tables for a performance domain using the callbacks
547 * defined in cb.
548 *
549 * The @microwatts is important to set with correct value. Some kernel
550 * sub-systems might rely on this flag and check if all devices in the EM are
551 * using the same scale.
552 *
553 * If multiple clients register the same performance domain, all but the first
554 * registration will be ignored.
555 *
556 * Return 0 on success
557 */
558int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states,
559 struct em_data_callback *cb, cpumask_t *cpus,
560 bool microwatts)
561{
562 unsigned long cap, prev_cap = 0;
563 unsigned long flags = 0;
564 int cpu, ret;
565
566 if (!dev || !nr_states || !cb)
567 return -EINVAL;
568
569 /*
570 * Use a mutex to serialize the registration of performance domains and
571 * let the driver-defined callback functions sleep.
572 */
573 mutex_lock(&em_pd_mutex);
574
575 if (dev->em_pd) {
576 ret = -EEXIST;
577 goto unlock;
578 }
579
580 if (_is_cpu_device(dev)) {
581 if (!cpus) {
582 dev_err(dev, "EM: invalid CPU mask\n");
583 ret = -EINVAL;
584 goto unlock;
585 }
586
587 for_each_cpu(cpu, cpus) {
588 if (em_cpu_get(cpu)) {
589 dev_err(dev, "EM: exists for CPU%d\n", cpu);
590 ret = -EEXIST;
591 goto unlock;
592 }
593 /*
594 * All CPUs of a domain must have the same
595 * micro-architecture since they all share the same
596 * table.
597 */
598 cap = arch_scale_cpu_capacity(cpu);
599 if (prev_cap && prev_cap != cap) {
600 dev_err(dev, "EM: CPUs of %*pbl must have the same capacity\n",
601 cpumask_pr_args(cpus));
602
603 ret = -EINVAL;
604 goto unlock;
605 }
606 prev_cap = cap;
607 }
608 }
609
610 if (microwatts)
611 flags |= EM_PERF_DOMAIN_MICROWATTS;
612 else if (cb->get_cost)
613 flags |= EM_PERF_DOMAIN_ARTIFICIAL;
614
615 /*
616 * EM only supports uW (exception is artificial EM).
617 * Therefore, check and force the drivers to provide
618 * power in uW.
619 */
620 if (!microwatts && !(flags & EM_PERF_DOMAIN_ARTIFICIAL)) {
621 dev_err(dev, "EM: only supports uW power values\n");
622 ret = -EINVAL;
623 goto unlock;
624 }
625
626 ret = em_create_pd(dev, nr_states, cb, cpus, flags);
627 if (ret)
628 goto unlock;
629
630 dev->em_pd->flags |= flags;
631
632 em_cpufreq_update_efficiencies(dev, dev->em_pd->em_table->state);
633
634 em_debug_create_pd(dev);
635 dev_info(dev, "EM: created perf domain\n");
636
637unlock:
638 mutex_unlock(&em_pd_mutex);
639
640 if (_is_cpu_device(dev))
641 em_check_capacity_update();
642
643 return ret;
644}
645EXPORT_SYMBOL_GPL(em_dev_register_perf_domain);
646
647/**
648 * em_dev_unregister_perf_domain() - Unregister Energy Model (EM) for a device
649 * @dev : Device for which the EM is registered
650 *
651 * Unregister the EM for the specified @dev (but not a CPU device).
652 */
653void em_dev_unregister_perf_domain(struct device *dev)
654{
655 if (IS_ERR_OR_NULL(dev) || !dev->em_pd)
656 return;
657
658 if (_is_cpu_device(dev))
659 return;
660
661 /*
662 * The mutex separates all register/unregister requests and protects
663 * from potential clean-up/setup issues in the debugfs directories.
664 * The debugfs directory name is the same as device's name.
665 */
666 mutex_lock(&em_pd_mutex);
667 em_debug_remove_pd(dev);
668
669 em_table_free(dev->em_pd->em_table);
670
671 kfree(dev->em_pd);
672 dev->em_pd = NULL;
673 mutex_unlock(&em_pd_mutex);
674}
675EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);
676
677/*
678 * Adjustment of CPU performance values after boot, when all CPUs capacites
679 * are correctly calculated.
680 */
681static void em_adjust_new_capacity(struct device *dev,
682 struct em_perf_domain *pd,
683 u64 max_cap)
684{
685 struct em_perf_table __rcu *em_table;
686 struct em_perf_state *ps, *new_ps;
687 int ret, ps_size;
688
689 em_table = em_table_alloc(pd);
690 if (!em_table) {
691 dev_warn(dev, "EM: allocation failed\n");
692 return;
693 }
694
695 new_ps = em_table->state;
696
697 rcu_read_lock();
698 ps = em_perf_state_from_pd(pd);
699 /* Initialize data based on old table */
700 ps_size = sizeof(struct em_perf_state) * pd->nr_perf_states;
701 memcpy(new_ps, ps, ps_size);
702
703 rcu_read_unlock();
704
705 em_init_performance(dev, pd, new_ps, pd->nr_perf_states);
706 ret = em_compute_costs(dev, new_ps, NULL, pd->nr_perf_states,
707 pd->flags);
708 if (ret) {
709 dev_warn(dev, "EM: compute costs failed\n");
710 return;
711 }
712
713 ret = em_dev_update_perf_domain(dev, em_table);
714 if (ret)
715 dev_warn(dev, "EM: update failed %d\n", ret);
716
717 /*
718 * This is one-time-update, so give up the ownership in this updater.
719 * The EM framework has incremented the usage counter and from now
720 * will keep the reference (then free the memory when needed).
721 */
722 em_table_free(em_table);
723}
724
725static void em_check_capacity_update(void)
726{
727 cpumask_var_t cpu_done_mask;
728 struct em_perf_state *table;
729 struct em_perf_domain *pd;
730 unsigned long cpu_capacity;
731 int cpu;
732
733 if (!zalloc_cpumask_var(&cpu_done_mask, GFP_KERNEL)) {
734 pr_warn("no free memory\n");
735 return;
736 }
737
738 /* Check if CPUs capacity has changed than update EM */
739 for_each_possible_cpu(cpu) {
740 struct cpufreq_policy *policy;
741 unsigned long em_max_perf;
742 struct device *dev;
743
744 if (cpumask_test_cpu(cpu, cpu_done_mask))
745 continue;
746
747 policy = cpufreq_cpu_get(cpu);
748 if (!policy) {
749 pr_debug("Accessing cpu%d policy failed\n", cpu);
750 schedule_delayed_work(&em_update_work,
751 msecs_to_jiffies(1000));
752 break;
753 }
754 cpufreq_cpu_put(policy);
755
756 pd = em_cpu_get(cpu);
757 if (!pd || em_is_artificial(pd))
758 continue;
759
760 cpumask_or(cpu_done_mask, cpu_done_mask,
761 em_span_cpus(pd));
762
763 cpu_capacity = arch_scale_cpu_capacity(cpu);
764
765 rcu_read_lock();
766 table = em_perf_state_from_pd(pd);
767 em_max_perf = table[pd->nr_perf_states - 1].performance;
768 rcu_read_unlock();
769
770 /*
771 * Check if the CPU capacity has been adjusted during boot
772 * and trigger the update for new performance values.
773 */
774 if (em_max_perf == cpu_capacity)
775 continue;
776
777 pr_debug("updating cpu%d cpu_cap=%lu old capacity=%lu\n",
778 cpu, cpu_capacity, em_max_perf);
779
780 dev = get_cpu_device(cpu);
781 em_adjust_new_capacity(dev, pd, cpu_capacity);
782 }
783
784 free_cpumask_var(cpu_done_mask);
785}
786
787static void em_update_workfn(struct work_struct *work)
788{
789 em_check_capacity_update();
790}