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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * System Control and Power Interface (SCMI) based CPUFreq Interface driver
4 *
5 * Copyright (C) 2018-2021 ARM Ltd.
6 * Sudeep Holla <sudeep.holla@arm.com>
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/clk-provider.h>
12#include <linux/cpu.h>
13#include <linux/cpufreq.h>
14#include <linux/cpumask.h>
15#include <linux/energy_model.h>
16#include <linux/export.h>
17#include <linux/module.h>
18#include <linux/pm_opp.h>
19#include <linux/slab.h>
20#include <linux/scmi_protocol.h>
21#include <linux/types.h>
22#include <linux/units.h>
23
24struct scmi_data {
25 int domain_id;
26 int nr_opp;
27 struct device *cpu_dev;
28 cpumask_var_t opp_shared_cpus;
29};
30
31static struct scmi_protocol_handle *ph;
32static const struct scmi_perf_proto_ops *perf_ops;
33static struct cpufreq_driver scmi_cpufreq_driver;
34
35static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
36{
37 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
38 struct scmi_data *priv = policy->driver_data;
39 unsigned long rate;
40 int ret;
41
42 ret = perf_ops->freq_get(ph, priv->domain_id, &rate, false);
43 if (ret)
44 return 0;
45 return rate / 1000;
46}
47
48/*
49 * perf_ops->freq_set is not a synchronous, the actual OPP change will
50 * happen asynchronously and can get notified if the events are
51 * subscribed for by the SCMI firmware
52 */
53static int
54scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
55{
56 struct scmi_data *priv = policy->driver_data;
57 u64 freq = policy->freq_table[index].frequency;
58
59 return perf_ops->freq_set(ph, priv->domain_id, freq * 1000, false);
60}
61
62static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
63 unsigned int target_freq)
64{
65 struct scmi_data *priv = policy->driver_data;
66 unsigned long freq = target_freq;
67
68 if (!perf_ops->freq_set(ph, priv->domain_id, freq * 1000, true))
69 return target_freq;
70
71 return 0;
72}
73
74static int scmi_cpu_domain_id(struct device *cpu_dev)
75{
76 struct device_node *np = cpu_dev->of_node;
77 struct of_phandle_args domain_id;
78 int index;
79
80 if (of_parse_phandle_with_args(np, "clocks", "#clock-cells", 0,
81 &domain_id)) {
82 /* Find the corresponding index for power-domain "perf". */
83 index = of_property_match_string(np, "power-domain-names",
84 "perf");
85 if (index < 0)
86 return -EINVAL;
87
88 if (of_parse_phandle_with_args(np, "power-domains",
89 "#power-domain-cells", index,
90 &domain_id))
91 return -EINVAL;
92 }
93
94 return domain_id.args[0];
95}
96
97static int
98scmi_get_sharing_cpus(struct device *cpu_dev, int domain,
99 struct cpumask *cpumask)
100{
101 int cpu, tdomain;
102 struct device *tcpu_dev;
103
104 for_each_possible_cpu(cpu) {
105 if (cpu == cpu_dev->id)
106 continue;
107
108 tcpu_dev = get_cpu_device(cpu);
109 if (!tcpu_dev)
110 continue;
111
112 tdomain = scmi_cpu_domain_id(tcpu_dev);
113 if (tdomain == domain)
114 cpumask_set_cpu(cpu, cpumask);
115 }
116
117 return 0;
118}
119
120static int __maybe_unused
121scmi_get_cpu_power(struct device *cpu_dev, unsigned long *power,
122 unsigned long *KHz)
123{
124 enum scmi_power_scale power_scale = perf_ops->power_scale_get(ph);
125 unsigned long Hz;
126 int ret, domain;
127
128 domain = scmi_cpu_domain_id(cpu_dev);
129 if (domain < 0)
130 return domain;
131
132 /* Get the power cost of the performance domain. */
133 Hz = *KHz * 1000;
134 ret = perf_ops->est_power_get(ph, domain, &Hz, power);
135 if (ret)
136 return ret;
137
138 /* Convert the power to uW if it is mW (ignore bogoW) */
139 if (power_scale == SCMI_POWER_MILLIWATTS)
140 *power *= MICROWATT_PER_MILLIWATT;
141
142 /* The EM framework specifies the frequency in KHz. */
143 *KHz = Hz / 1000;
144
145 return 0;
146}
147
148static int
149scmi_get_rate_limit(u32 domain, bool has_fast_switch)
150{
151 int ret, rate_limit;
152
153 if (has_fast_switch) {
154 /*
155 * Fast channels are used whenever available,
156 * so use their rate_limit value if populated.
157 */
158 ret = perf_ops->fast_switch_rate_limit(ph, domain,
159 &rate_limit);
160 if (!ret && rate_limit)
161 return rate_limit;
162 }
163
164 ret = perf_ops->rate_limit_get(ph, domain, &rate_limit);
165 if (ret)
166 return 0;
167
168 return rate_limit;
169}
170
171static struct freq_attr *scmi_cpufreq_hw_attr[] = {
172 &cpufreq_freq_attr_scaling_available_freqs,
173 NULL,
174 NULL,
175};
176
177static int scmi_cpufreq_init(struct cpufreq_policy *policy)
178{
179 int ret, nr_opp, domain;
180 unsigned int latency;
181 struct device *cpu_dev;
182 struct scmi_data *priv;
183 struct cpufreq_frequency_table *freq_table;
184
185 cpu_dev = get_cpu_device(policy->cpu);
186 if (!cpu_dev) {
187 pr_err("failed to get cpu%d device\n", policy->cpu);
188 return -ENODEV;
189 }
190
191 domain = scmi_cpu_domain_id(cpu_dev);
192 if (domain < 0)
193 return domain;
194
195 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
196 if (!priv)
197 return -ENOMEM;
198
199 if (!zalloc_cpumask_var(&priv->opp_shared_cpus, GFP_KERNEL)) {
200 ret = -ENOMEM;
201 goto out_free_priv;
202 }
203
204 /* Obtain CPUs that share SCMI performance controls */
205 ret = scmi_get_sharing_cpus(cpu_dev, domain, policy->cpus);
206 if (ret) {
207 dev_warn(cpu_dev, "failed to get sharing cpumask\n");
208 goto out_free_cpumask;
209 }
210
211 /*
212 * Obtain CPUs that share performance levels.
213 * The OPP 'sharing cpus' info may come from DT through an empty opp
214 * table and opp-shared.
215 */
216 ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
217 if (ret || cpumask_empty(priv->opp_shared_cpus)) {
218 /*
219 * Either opp-table is not set or no opp-shared was found.
220 * Use the CPU mask from SCMI to designate CPUs sharing an OPP
221 * table.
222 */
223 cpumask_copy(priv->opp_shared_cpus, policy->cpus);
224 }
225
226 /*
227 * A previous CPU may have marked OPPs as shared for a few CPUs, based on
228 * what OPP core provided. If the current CPU is part of those few, then
229 * there is no need to add OPPs again.
230 */
231 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
232 if (nr_opp <= 0) {
233 ret = perf_ops->device_opps_add(ph, cpu_dev, domain);
234 if (ret) {
235 dev_warn(cpu_dev, "failed to add opps to the device\n");
236 goto out_free_cpumask;
237 }
238
239 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
240 if (nr_opp <= 0) {
241 dev_err(cpu_dev, "%s: No OPPs for this device: %d\n",
242 __func__, nr_opp);
243
244 ret = -ENODEV;
245 goto out_free_opp;
246 }
247
248 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
249 if (ret) {
250 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
251 __func__, ret);
252
253 goto out_free_opp;
254 }
255
256 priv->nr_opp = nr_opp;
257 }
258
259 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
260 if (ret) {
261 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
262 goto out_free_opp;
263 }
264
265 priv->cpu_dev = cpu_dev;
266 priv->domain_id = domain;
267
268 policy->driver_data = priv;
269 policy->freq_table = freq_table;
270
271 /* SCMI allows DVFS request for any domain from any CPU */
272 policy->dvfs_possible_from_any_cpu = true;
273
274 latency = perf_ops->transition_latency_get(ph, domain);
275 if (!latency)
276 latency = CPUFREQ_ETERNAL;
277
278 policy->cpuinfo.transition_latency = latency;
279
280 policy->fast_switch_possible =
281 perf_ops->fast_switch_possible(ph, domain);
282
283 policy->transition_delay_us =
284 scmi_get_rate_limit(domain, policy->fast_switch_possible);
285
286 if (policy_has_boost_freq(policy)) {
287 ret = cpufreq_enable_boost_support();
288 if (ret) {
289 dev_warn(cpu_dev, "failed to enable boost: %d\n", ret);
290 goto out_free_table;
291 } else {
292 scmi_cpufreq_hw_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
293 scmi_cpufreq_driver.boost_enabled = true;
294 }
295 }
296
297 return 0;
298
299out_free_table:
300 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
301out_free_opp:
302 dev_pm_opp_remove_all_dynamic(cpu_dev);
303
304out_free_cpumask:
305 free_cpumask_var(priv->opp_shared_cpus);
306
307out_free_priv:
308 kfree(priv);
309
310 return ret;
311}
312
313static void scmi_cpufreq_exit(struct cpufreq_policy *policy)
314{
315 struct scmi_data *priv = policy->driver_data;
316
317 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
318 dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
319 free_cpumask_var(priv->opp_shared_cpus);
320 kfree(priv);
321}
322
323static void scmi_cpufreq_register_em(struct cpufreq_policy *policy)
324{
325 struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
326 enum scmi_power_scale power_scale = perf_ops->power_scale_get(ph);
327 struct scmi_data *priv = policy->driver_data;
328 bool em_power_scale = false;
329
330 /*
331 * This callback will be called for each policy, but we don't need to
332 * register with EM every time. Despite not being part of the same
333 * policy, some CPUs may still share their perf-domains, and a CPU from
334 * another policy may already have registered with EM on behalf of CPUs
335 * of this policy.
336 */
337 if (!priv->nr_opp)
338 return;
339
340 if (power_scale == SCMI_POWER_MILLIWATTS
341 || power_scale == SCMI_POWER_MICROWATTS)
342 em_power_scale = true;
343
344 em_dev_register_perf_domain(get_cpu_device(policy->cpu), priv->nr_opp,
345 &em_cb, priv->opp_shared_cpus,
346 em_power_scale);
347}
348
349static struct cpufreq_driver scmi_cpufreq_driver = {
350 .name = "scmi",
351 .flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
352 CPUFREQ_NEED_INITIAL_FREQ_CHECK |
353 CPUFREQ_IS_COOLING_DEV,
354 .verify = cpufreq_generic_frequency_table_verify,
355 .attr = scmi_cpufreq_hw_attr,
356 .target_index = scmi_cpufreq_set_target,
357 .fast_switch = scmi_cpufreq_fast_switch,
358 .get = scmi_cpufreq_get_rate,
359 .init = scmi_cpufreq_init,
360 .exit = scmi_cpufreq_exit,
361 .register_em = scmi_cpufreq_register_em,
362};
363
364static int scmi_cpufreq_probe(struct scmi_device *sdev)
365{
366 int ret;
367 struct device *dev = &sdev->dev;
368 const struct scmi_handle *handle;
369
370 handle = sdev->handle;
371
372 if (!handle)
373 return -ENODEV;
374
375 perf_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_PERF, &ph);
376 if (IS_ERR(perf_ops))
377 return PTR_ERR(perf_ops);
378
379#ifdef CONFIG_COMMON_CLK
380 /* dummy clock provider as needed by OPP if clocks property is used */
381 if (of_property_present(dev->of_node, "#clock-cells")) {
382 ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, NULL);
383 if (ret)
384 return dev_err_probe(dev, ret, "%s: registering clock provider failed\n", __func__);
385 }
386#endif
387
388 ret = cpufreq_register_driver(&scmi_cpufreq_driver);
389 if (ret) {
390 dev_err(dev, "%s: registering cpufreq failed, err: %d\n",
391 __func__, ret);
392 }
393
394 return ret;
395}
396
397static void scmi_cpufreq_remove(struct scmi_device *sdev)
398{
399 cpufreq_unregister_driver(&scmi_cpufreq_driver);
400}
401
402static const struct scmi_device_id scmi_id_table[] = {
403 { SCMI_PROTOCOL_PERF, "cpufreq" },
404 { },
405};
406MODULE_DEVICE_TABLE(scmi, scmi_id_table);
407
408static struct scmi_driver scmi_cpufreq_drv = {
409 .name = "scmi-cpufreq",
410 .probe = scmi_cpufreq_probe,
411 .remove = scmi_cpufreq_remove,
412 .id_table = scmi_id_table,
413};
414module_scmi_driver(scmi_cpufreq_drv);
415
416MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
417MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
418MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * System Control and Power Interface (SCMI) based CPUFreq Interface driver
4 *
5 * Copyright (C) 2018 ARM Ltd.
6 * Sudeep Holla <sudeep.holla@arm.com>
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/cpu.h>
12#include <linux/cpufreq.h>
13#include <linux/cpumask.h>
14#include <linux/cpu_cooling.h>
15#include <linux/export.h>
16#include <linux/module.h>
17#include <linux/pm_opp.h>
18#include <linux/slab.h>
19#include <linux/scmi_protocol.h>
20#include <linux/types.h>
21
22struct scmi_data {
23 int domain_id;
24 struct device *cpu_dev;
25 struct thermal_cooling_device *cdev;
26};
27
28static const struct scmi_handle *handle;
29
30static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
31{
32 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
33 struct scmi_perf_ops *perf_ops = handle->perf_ops;
34 struct scmi_data *priv = policy->driver_data;
35 unsigned long rate;
36 int ret;
37
38 ret = perf_ops->freq_get(handle, priv->domain_id, &rate, false);
39 if (ret)
40 return 0;
41 return rate / 1000;
42}
43
44/*
45 * perf_ops->freq_set is not a synchronous, the actual OPP change will
46 * happen asynchronously and can get notified if the events are
47 * subscribed for by the SCMI firmware
48 */
49static int
50scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
51{
52 int ret;
53 struct scmi_data *priv = policy->driver_data;
54 struct scmi_perf_ops *perf_ops = handle->perf_ops;
55 u64 freq = policy->freq_table[index].frequency * 1000;
56
57 ret = perf_ops->freq_set(handle, priv->domain_id, freq, false);
58 if (!ret)
59 arch_set_freq_scale(policy->related_cpus, freq,
60 policy->cpuinfo.max_freq);
61 return ret;
62}
63
64static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
65 unsigned int target_freq)
66{
67 struct scmi_data *priv = policy->driver_data;
68 struct scmi_perf_ops *perf_ops = handle->perf_ops;
69
70 if (!perf_ops->freq_set(handle, priv->domain_id,
71 target_freq * 1000, true)) {
72 arch_set_freq_scale(policy->related_cpus, target_freq,
73 policy->cpuinfo.max_freq);
74 return target_freq;
75 }
76
77 return 0;
78}
79
80static int
81scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
82{
83 int cpu, domain, tdomain;
84 struct device *tcpu_dev;
85
86 domain = handle->perf_ops->device_domain_id(cpu_dev);
87 if (domain < 0)
88 return domain;
89
90 for_each_possible_cpu(cpu) {
91 if (cpu == cpu_dev->id)
92 continue;
93
94 tcpu_dev = get_cpu_device(cpu);
95 if (!tcpu_dev)
96 continue;
97
98 tdomain = handle->perf_ops->device_domain_id(tcpu_dev);
99 if (tdomain == domain)
100 cpumask_set_cpu(cpu, cpumask);
101 }
102
103 return 0;
104}
105
106static int scmi_cpufreq_init(struct cpufreq_policy *policy)
107{
108 int ret;
109 unsigned int latency;
110 struct device *cpu_dev;
111 struct scmi_data *priv;
112 struct cpufreq_frequency_table *freq_table;
113
114 cpu_dev = get_cpu_device(policy->cpu);
115 if (!cpu_dev) {
116 pr_err("failed to get cpu%d device\n", policy->cpu);
117 return -ENODEV;
118 }
119
120 ret = handle->perf_ops->add_opps_to_device(handle, cpu_dev);
121 if (ret) {
122 dev_warn(cpu_dev, "failed to add opps to the device\n");
123 return ret;
124 }
125
126 ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
127 if (ret) {
128 dev_warn(cpu_dev, "failed to get sharing cpumask\n");
129 return ret;
130 }
131
132 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
133 if (ret) {
134 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
135 __func__, ret);
136 return ret;
137 }
138
139 ret = dev_pm_opp_get_opp_count(cpu_dev);
140 if (ret <= 0) {
141 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
142 ret = -EPROBE_DEFER;
143 goto out_free_opp;
144 }
145
146 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
147 if (!priv) {
148 ret = -ENOMEM;
149 goto out_free_opp;
150 }
151
152 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
153 if (ret) {
154 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
155 goto out_free_priv;
156 }
157
158 priv->cpu_dev = cpu_dev;
159 priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev);
160
161 policy->driver_data = priv;
162 policy->freq_table = freq_table;
163
164 /* SCMI allows DVFS request for any domain from any CPU */
165 policy->dvfs_possible_from_any_cpu = true;
166
167 latency = handle->perf_ops->get_transition_latency(handle, cpu_dev);
168 if (!latency)
169 latency = CPUFREQ_ETERNAL;
170
171 policy->cpuinfo.transition_latency = latency;
172
173 policy->fast_switch_possible = true;
174 return 0;
175
176out_free_priv:
177 kfree(priv);
178out_free_opp:
179 dev_pm_opp_cpumask_remove_table(policy->cpus);
180
181 return ret;
182}
183
184static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
185{
186 struct scmi_data *priv = policy->driver_data;
187
188 cpufreq_cooling_unregister(priv->cdev);
189 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
190 kfree(priv);
191 dev_pm_opp_cpumask_remove_table(policy->related_cpus);
192
193 return 0;
194}
195
196static void scmi_cpufreq_ready(struct cpufreq_policy *policy)
197{
198 struct scmi_data *priv = policy->driver_data;
199
200 priv->cdev = of_cpufreq_cooling_register(policy);
201}
202
203static struct cpufreq_driver scmi_cpufreq_driver = {
204 .name = "scmi",
205 .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
206 CPUFREQ_NEED_INITIAL_FREQ_CHECK,
207 .verify = cpufreq_generic_frequency_table_verify,
208 .attr = cpufreq_generic_attr,
209 .target_index = scmi_cpufreq_set_target,
210 .fast_switch = scmi_cpufreq_fast_switch,
211 .get = scmi_cpufreq_get_rate,
212 .init = scmi_cpufreq_init,
213 .exit = scmi_cpufreq_exit,
214 .ready = scmi_cpufreq_ready,
215};
216
217static int scmi_cpufreq_probe(struct scmi_device *sdev)
218{
219 int ret;
220
221 handle = sdev->handle;
222
223 if (!handle || !handle->perf_ops)
224 return -ENODEV;
225
226 ret = cpufreq_register_driver(&scmi_cpufreq_driver);
227 if (ret) {
228 dev_err(&sdev->dev, "%s: registering cpufreq failed, err: %d\n",
229 __func__, ret);
230 }
231
232 return ret;
233}
234
235static void scmi_cpufreq_remove(struct scmi_device *sdev)
236{
237 cpufreq_unregister_driver(&scmi_cpufreq_driver);
238}
239
240static const struct scmi_device_id scmi_id_table[] = {
241 { SCMI_PROTOCOL_PERF },
242 { },
243};
244MODULE_DEVICE_TABLE(scmi, scmi_id_table);
245
246static struct scmi_driver scmi_cpufreq_drv = {
247 .name = "scmi-cpufreq",
248 .probe = scmi_cpufreq_probe,
249 .remove = scmi_cpufreq_remove,
250 .id_table = scmi_id_table,
251};
252module_scmi_driver(scmi_cpufreq_drv);
253
254MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
255MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
256MODULE_LICENSE("GPL v2");