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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 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/energy_model.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};
26
27static const struct scmi_handle *handle;
28
29static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
30{
31 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
32 struct scmi_perf_ops *perf_ops = handle->perf_ops;
33 struct scmi_data *priv = policy->driver_data;
34 unsigned long rate;
35 int ret;
36
37 ret = perf_ops->freq_get(handle, priv->domain_id, &rate, false);
38 if (ret)
39 return 0;
40 return rate / 1000;
41}
42
43/*
44 * perf_ops->freq_set is not a synchronous, the actual OPP change will
45 * happen asynchronously and can get notified if the events are
46 * subscribed for by the SCMI firmware
47 */
48static int
49scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
50{
51 int ret;
52 struct scmi_data *priv = policy->driver_data;
53 struct scmi_perf_ops *perf_ops = handle->perf_ops;
54 u64 freq = policy->freq_table[index].frequency;
55
56 ret = perf_ops->freq_set(handle, priv->domain_id, freq * 1000, false);
57 if (!ret)
58 arch_set_freq_scale(policy->related_cpus, freq,
59 policy->cpuinfo.max_freq);
60 return ret;
61}
62
63static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
64 unsigned int target_freq)
65{
66 struct scmi_data *priv = policy->driver_data;
67 struct scmi_perf_ops *perf_ops = handle->perf_ops;
68
69 if (!perf_ops->freq_set(handle, priv->domain_id,
70 target_freq * 1000, true)) {
71 arch_set_freq_scale(policy->related_cpus, target_freq,
72 policy->cpuinfo.max_freq);
73 return target_freq;
74 }
75
76 return 0;
77}
78
79static int
80scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
81{
82 int cpu, domain, tdomain;
83 struct device *tcpu_dev;
84
85 domain = handle->perf_ops->device_domain_id(cpu_dev);
86 if (domain < 0)
87 return domain;
88
89 for_each_possible_cpu(cpu) {
90 if (cpu == cpu_dev->id)
91 continue;
92
93 tcpu_dev = get_cpu_device(cpu);
94 if (!tcpu_dev)
95 continue;
96
97 tdomain = handle->perf_ops->device_domain_id(tcpu_dev);
98 if (tdomain == domain)
99 cpumask_set_cpu(cpu, cpumask);
100 }
101
102 return 0;
103}
104
105static int __maybe_unused
106scmi_get_cpu_power(unsigned long *power, unsigned long *KHz,
107 struct device *cpu_dev)
108{
109 unsigned long Hz;
110 int ret, domain;
111
112 domain = handle->perf_ops->device_domain_id(cpu_dev);
113 if (domain < 0)
114 return domain;
115
116 /* Get the power cost of the performance domain. */
117 Hz = *KHz * 1000;
118 ret = handle->perf_ops->est_power_get(handle, domain, &Hz, power);
119 if (ret)
120 return ret;
121
122 /* The EM framework specifies the frequency in KHz. */
123 *KHz = Hz / 1000;
124
125 return 0;
126}
127
128static int scmi_cpufreq_init(struct cpufreq_policy *policy)
129{
130 int ret, nr_opp;
131 unsigned int latency;
132 struct device *cpu_dev;
133 struct scmi_data *priv;
134 struct cpufreq_frequency_table *freq_table;
135 struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
136
137 cpu_dev = get_cpu_device(policy->cpu);
138 if (!cpu_dev) {
139 pr_err("failed to get cpu%d device\n", policy->cpu);
140 return -ENODEV;
141 }
142
143 ret = handle->perf_ops->device_opps_add(handle, cpu_dev);
144 if (ret) {
145 dev_warn(cpu_dev, "failed to add opps to the device\n");
146 return ret;
147 }
148
149 ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
150 if (ret) {
151 dev_warn(cpu_dev, "failed to get sharing cpumask\n");
152 return ret;
153 }
154
155 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
156 if (ret) {
157 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
158 __func__, ret);
159 return ret;
160 }
161
162 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
163 if (nr_opp <= 0) {
164 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
165 ret = -EPROBE_DEFER;
166 goto out_free_opp;
167 }
168
169 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
170 if (!priv) {
171 ret = -ENOMEM;
172 goto out_free_opp;
173 }
174
175 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
176 if (ret) {
177 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
178 goto out_free_priv;
179 }
180
181 priv->cpu_dev = cpu_dev;
182 priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev);
183
184 policy->driver_data = priv;
185 policy->freq_table = freq_table;
186
187 /* SCMI allows DVFS request for any domain from any CPU */
188 policy->dvfs_possible_from_any_cpu = true;
189
190 latency = handle->perf_ops->transition_latency_get(handle, cpu_dev);
191 if (!latency)
192 latency = CPUFREQ_ETERNAL;
193
194 policy->cpuinfo.transition_latency = latency;
195
196 policy->fast_switch_possible =
197 handle->perf_ops->fast_switch_possible(handle, cpu_dev);
198
199 em_dev_register_perf_domain(cpu_dev, nr_opp, &em_cb, policy->cpus);
200
201 return 0;
202
203out_free_priv:
204 kfree(priv);
205out_free_opp:
206 dev_pm_opp_remove_all_dynamic(cpu_dev);
207
208 return ret;
209}
210
211static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
212{
213 struct scmi_data *priv = policy->driver_data;
214
215 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
216 dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
217 kfree(priv);
218
219 return 0;
220}
221
222static struct cpufreq_driver scmi_cpufreq_driver = {
223 .name = "scmi",
224 .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
225 CPUFREQ_NEED_INITIAL_FREQ_CHECK |
226 CPUFREQ_IS_COOLING_DEV,
227 .verify = cpufreq_generic_frequency_table_verify,
228 .attr = cpufreq_generic_attr,
229 .target_index = scmi_cpufreq_set_target,
230 .fast_switch = scmi_cpufreq_fast_switch,
231 .get = scmi_cpufreq_get_rate,
232 .init = scmi_cpufreq_init,
233 .exit = scmi_cpufreq_exit,
234};
235
236static int scmi_cpufreq_probe(struct scmi_device *sdev)
237{
238 int ret;
239
240 handle = sdev->handle;
241
242 if (!handle || !handle->perf_ops)
243 return -ENODEV;
244
245 ret = cpufreq_register_driver(&scmi_cpufreq_driver);
246 if (ret) {
247 dev_err(&sdev->dev, "%s: registering cpufreq failed, err: %d\n",
248 __func__, ret);
249 }
250
251 return ret;
252}
253
254static void scmi_cpufreq_remove(struct scmi_device *sdev)
255{
256 cpufreq_unregister_driver(&scmi_cpufreq_driver);
257}
258
259static const struct scmi_device_id scmi_id_table[] = {
260 { SCMI_PROTOCOL_PERF, "cpufreq" },
261 { },
262};
263MODULE_DEVICE_TABLE(scmi, scmi_id_table);
264
265static struct scmi_driver scmi_cpufreq_drv = {
266 .name = "scmi-cpufreq",
267 .probe = scmi_cpufreq_probe,
268 .remove = scmi_cpufreq_remove,
269 .id_table = scmi_id_table,
270};
271module_scmi_driver(scmi_cpufreq_drv);
272
273MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
274MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
275MODULE_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) 2018-2021 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;
33
34static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
35{
36 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
37 struct scmi_data *priv = policy->driver_data;
38 unsigned long rate;
39 int ret;
40
41 ret = perf_ops->freq_get(ph, priv->domain_id, &rate, false);
42 if (ret)
43 return 0;
44 return rate / 1000;
45}
46
47/*
48 * perf_ops->freq_set is not a synchronous, the actual OPP change will
49 * happen asynchronously and can get notified if the events are
50 * subscribed for by the SCMI firmware
51 */
52static int
53scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
54{
55 struct scmi_data *priv = policy->driver_data;
56 u64 freq = policy->freq_table[index].frequency;
57
58 return perf_ops->freq_set(ph, priv->domain_id, freq * 1000, false);
59}
60
61static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
62 unsigned int target_freq)
63{
64 struct scmi_data *priv = policy->driver_data;
65
66 if (!perf_ops->freq_set(ph, priv->domain_id,
67 target_freq * 1000, true))
68 return target_freq;
69
70 return 0;
71}
72
73static int
74scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
75{
76 int cpu, domain, tdomain;
77 struct device *tcpu_dev;
78
79 domain = perf_ops->device_domain_id(cpu_dev);
80 if (domain < 0)
81 return domain;
82
83 for_each_possible_cpu(cpu) {
84 if (cpu == cpu_dev->id)
85 continue;
86
87 tcpu_dev = get_cpu_device(cpu);
88 if (!tcpu_dev)
89 continue;
90
91 tdomain = perf_ops->device_domain_id(tcpu_dev);
92 if (tdomain == domain)
93 cpumask_set_cpu(cpu, cpumask);
94 }
95
96 return 0;
97}
98
99static int __maybe_unused
100scmi_get_cpu_power(struct device *cpu_dev, unsigned long *power,
101 unsigned long *KHz)
102{
103 enum scmi_power_scale power_scale = perf_ops->power_scale_get(ph);
104 unsigned long Hz;
105 int ret, domain;
106
107 domain = perf_ops->device_domain_id(cpu_dev);
108 if (domain < 0)
109 return domain;
110
111 /* Get the power cost of the performance domain. */
112 Hz = *KHz * 1000;
113 ret = perf_ops->est_power_get(ph, domain, &Hz, power);
114 if (ret)
115 return ret;
116
117 /* Convert the power to uW if it is mW (ignore bogoW) */
118 if (power_scale == SCMI_POWER_MILLIWATTS)
119 *power *= MICROWATT_PER_MILLIWATT;
120
121 /* The EM framework specifies the frequency in KHz. */
122 *KHz = Hz / 1000;
123
124 return 0;
125}
126
127static int scmi_cpufreq_init(struct cpufreq_policy *policy)
128{
129 int ret, nr_opp;
130 unsigned int latency;
131 struct device *cpu_dev;
132 struct scmi_data *priv;
133 struct cpufreq_frequency_table *freq_table;
134
135 cpu_dev = get_cpu_device(policy->cpu);
136 if (!cpu_dev) {
137 pr_err("failed to get cpu%d device\n", policy->cpu);
138 return -ENODEV;
139 }
140
141 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
142 if (!priv)
143 return -ENOMEM;
144
145 if (!zalloc_cpumask_var(&priv->opp_shared_cpus, GFP_KERNEL)) {
146 ret = -ENOMEM;
147 goto out_free_priv;
148 }
149
150 /* Obtain CPUs that share SCMI performance controls */
151 ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
152 if (ret) {
153 dev_warn(cpu_dev, "failed to get sharing cpumask\n");
154 goto out_free_cpumask;
155 }
156
157 /*
158 * Obtain CPUs that share performance levels.
159 * The OPP 'sharing cpus' info may come from DT through an empty opp
160 * table and opp-shared.
161 */
162 ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
163 if (ret || cpumask_empty(priv->opp_shared_cpus)) {
164 /*
165 * Either opp-table is not set or no opp-shared was found.
166 * Use the CPU mask from SCMI to designate CPUs sharing an OPP
167 * table.
168 */
169 cpumask_copy(priv->opp_shared_cpus, policy->cpus);
170 }
171
172 /*
173 * A previous CPU may have marked OPPs as shared for a few CPUs, based on
174 * what OPP core provided. If the current CPU is part of those few, then
175 * there is no need to add OPPs again.
176 */
177 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
178 if (nr_opp <= 0) {
179 ret = perf_ops->device_opps_add(ph, cpu_dev);
180 if (ret) {
181 dev_warn(cpu_dev, "failed to add opps to the device\n");
182 goto out_free_cpumask;
183 }
184
185 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
186 if (nr_opp <= 0) {
187 dev_err(cpu_dev, "%s: No OPPs for this device: %d\n",
188 __func__, nr_opp);
189
190 ret = -ENODEV;
191 goto out_free_opp;
192 }
193
194 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
195 if (ret) {
196 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
197 __func__, ret);
198
199 goto out_free_opp;
200 }
201
202 priv->nr_opp = nr_opp;
203 }
204
205 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
206 if (ret) {
207 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
208 goto out_free_opp;
209 }
210
211 priv->cpu_dev = cpu_dev;
212 priv->domain_id = perf_ops->device_domain_id(cpu_dev);
213
214 policy->driver_data = priv;
215 policy->freq_table = freq_table;
216
217 /* SCMI allows DVFS request for any domain from any CPU */
218 policy->dvfs_possible_from_any_cpu = true;
219
220 latency = perf_ops->transition_latency_get(ph, cpu_dev);
221 if (!latency)
222 latency = CPUFREQ_ETERNAL;
223
224 policy->cpuinfo.transition_latency = latency;
225
226 policy->fast_switch_possible =
227 perf_ops->fast_switch_possible(ph, cpu_dev);
228
229 return 0;
230
231out_free_opp:
232 dev_pm_opp_remove_all_dynamic(cpu_dev);
233
234out_free_cpumask:
235 free_cpumask_var(priv->opp_shared_cpus);
236
237out_free_priv:
238 kfree(priv);
239
240 return ret;
241}
242
243static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
244{
245 struct scmi_data *priv = policy->driver_data;
246
247 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
248 dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
249 free_cpumask_var(priv->opp_shared_cpus);
250 kfree(priv);
251
252 return 0;
253}
254
255static void scmi_cpufreq_register_em(struct cpufreq_policy *policy)
256{
257 struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
258 enum scmi_power_scale power_scale = perf_ops->power_scale_get(ph);
259 struct scmi_data *priv = policy->driver_data;
260 bool em_power_scale = false;
261
262 /*
263 * This callback will be called for each policy, but we don't need to
264 * register with EM every time. Despite not being part of the same
265 * policy, some CPUs may still share their perf-domains, and a CPU from
266 * another policy may already have registered with EM on behalf of CPUs
267 * of this policy.
268 */
269 if (!priv->nr_opp)
270 return;
271
272 if (power_scale == SCMI_POWER_MILLIWATTS
273 || power_scale == SCMI_POWER_MICROWATTS)
274 em_power_scale = true;
275
276 em_dev_register_perf_domain(get_cpu_device(policy->cpu), priv->nr_opp,
277 &em_cb, priv->opp_shared_cpus,
278 em_power_scale);
279}
280
281static struct cpufreq_driver scmi_cpufreq_driver = {
282 .name = "scmi",
283 .flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
284 CPUFREQ_NEED_INITIAL_FREQ_CHECK |
285 CPUFREQ_IS_COOLING_DEV,
286 .verify = cpufreq_generic_frequency_table_verify,
287 .attr = cpufreq_generic_attr,
288 .target_index = scmi_cpufreq_set_target,
289 .fast_switch = scmi_cpufreq_fast_switch,
290 .get = scmi_cpufreq_get_rate,
291 .init = scmi_cpufreq_init,
292 .exit = scmi_cpufreq_exit,
293 .register_em = scmi_cpufreq_register_em,
294};
295
296static int scmi_cpufreq_probe(struct scmi_device *sdev)
297{
298 int ret;
299 struct device *dev = &sdev->dev;
300 const struct scmi_handle *handle;
301
302 handle = sdev->handle;
303
304 if (!handle)
305 return -ENODEV;
306
307 perf_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_PERF, &ph);
308 if (IS_ERR(perf_ops))
309 return PTR_ERR(perf_ops);
310
311#ifdef CONFIG_COMMON_CLK
312 /* dummy clock provider as needed by OPP if clocks property is used */
313 if (of_find_property(dev->of_node, "#clock-cells", NULL))
314 devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, NULL);
315#endif
316
317 ret = cpufreq_register_driver(&scmi_cpufreq_driver);
318 if (ret) {
319 dev_err(dev, "%s: registering cpufreq failed, err: %d\n",
320 __func__, ret);
321 }
322
323 return ret;
324}
325
326static void scmi_cpufreq_remove(struct scmi_device *sdev)
327{
328 cpufreq_unregister_driver(&scmi_cpufreq_driver);
329}
330
331static const struct scmi_device_id scmi_id_table[] = {
332 { SCMI_PROTOCOL_PERF, "cpufreq" },
333 { },
334};
335MODULE_DEVICE_TABLE(scmi, scmi_id_table);
336
337static struct scmi_driver scmi_cpufreq_drv = {
338 .name = "scmi-cpufreq",
339 .probe = scmi_cpufreq_probe,
340 .remove = scmi_cpufreq_remove,
341 .id_table = scmi_id_table,
342};
343module_scmi_driver(scmi_cpufreq_drv);
344
345MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
346MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
347MODULE_LICENSE("GPL v2");