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99d6bdf3 SH |
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> | |
3c429851 | 14 | #include <linux/energy_model.h> |
99d6bdf3 SH |
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 | ||
22 | struct scmi_data { | |
23 | int domain_id; | |
24 | struct device *cpu_dev; | |
99d6bdf3 SH |
25 | }; |
26 | ||
27 | static const struct scmi_handle *handle; | |
28 | ||
29 | static 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 | */ | |
48 | static int | |
49 | scmi_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; | |
0e141d1c | 54 | u64 freq = policy->freq_table[index].frequency; |
99d6bdf3 | 55 | |
0e141d1c | 56 | ret = perf_ops->freq_set(handle, priv->domain_id, freq * 1000, false); |
99d6bdf3 SH |
57 | if (!ret) |
58 | arch_set_freq_scale(policy->related_cpus, freq, | |
59 | policy->cpuinfo.max_freq); | |
60 | return ret; | |
61 | } | |
62 | ||
02f208c5 SH |
63 | static 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 | ||
99d6bdf3 SH |
79 | static int |
80 | scmi_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 | ||
3c429851 QP |
105 | static int __maybe_unused |
106 | scmi_get_cpu_power(unsigned long *power, unsigned long *KHz, int cpu) | |
107 | { | |
108 | struct device *cpu_dev = get_cpu_device(cpu); | |
109 | unsigned long Hz; | |
110 | int ret, domain; | |
111 | ||
112 | if (!cpu_dev) { | |
113 | pr_err("failed to get cpu%d device\n", cpu); | |
114 | return -ENODEV; | |
115 | } | |
116 | ||
117 | domain = handle->perf_ops->device_domain_id(cpu_dev); | |
118 | if (domain < 0) | |
119 | return domain; | |
120 | ||
121 | /* Get the power cost of the performance domain. */ | |
122 | Hz = *KHz * 1000; | |
123 | ret = handle->perf_ops->est_power_get(handle, domain, &Hz, power); | |
124 | if (ret) | |
125 | return ret; | |
126 | ||
127 | /* The EM framework specifies the frequency in KHz. */ | |
128 | *KHz = Hz / 1000; | |
129 | ||
130 | return 0; | |
131 | } | |
132 | ||
99d6bdf3 SH |
133 | static int scmi_cpufreq_init(struct cpufreq_policy *policy) |
134 | { | |
3c429851 | 135 | int ret, nr_opp; |
99d6bdf3 SH |
136 | unsigned int latency; |
137 | struct device *cpu_dev; | |
138 | struct scmi_data *priv; | |
139 | struct cpufreq_frequency_table *freq_table; | |
3c429851 | 140 | struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power); |
99d6bdf3 SH |
141 | |
142 | cpu_dev = get_cpu_device(policy->cpu); | |
143 | if (!cpu_dev) { | |
144 | pr_err("failed to get cpu%d device\n", policy->cpu); | |
145 | return -ENODEV; | |
146 | } | |
147 | ||
7859e08c | 148 | ret = handle->perf_ops->device_opps_add(handle, cpu_dev); |
99d6bdf3 SH |
149 | if (ret) { |
150 | dev_warn(cpu_dev, "failed to add opps to the device\n"); | |
151 | return ret; | |
152 | } | |
153 | ||
154 | ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus); | |
155 | if (ret) { | |
156 | dev_warn(cpu_dev, "failed to get sharing cpumask\n"); | |
157 | return ret; | |
158 | } | |
159 | ||
160 | ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus); | |
161 | if (ret) { | |
162 | dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", | |
163 | __func__, ret); | |
164 | return ret; | |
165 | } | |
166 | ||
3c429851 QP |
167 | nr_opp = dev_pm_opp_get_opp_count(cpu_dev); |
168 | if (nr_opp <= 0) { | |
99d6bdf3 SH |
169 | dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); |
170 | ret = -EPROBE_DEFER; | |
171 | goto out_free_opp; | |
172 | } | |
173 | ||
174 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
175 | if (!priv) { | |
176 | ret = -ENOMEM; | |
177 | goto out_free_opp; | |
178 | } | |
179 | ||
180 | ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); | |
181 | if (ret) { | |
182 | dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret); | |
183 | goto out_free_priv; | |
184 | } | |
185 | ||
186 | priv->cpu_dev = cpu_dev; | |
187 | priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev); | |
188 | ||
189 | policy->driver_data = priv; | |
d983af98 | 190 | policy->freq_table = freq_table; |
99d6bdf3 SH |
191 | |
192 | /* SCMI allows DVFS request for any domain from any CPU */ | |
193 | policy->dvfs_possible_from_any_cpu = true; | |
194 | ||
7859e08c | 195 | latency = handle->perf_ops->transition_latency_get(handle, cpu_dev); |
99d6bdf3 SH |
196 | if (!latency) |
197 | latency = CPUFREQ_ETERNAL; | |
198 | ||
199 | policy->cpuinfo.transition_latency = latency; | |
200 | ||
02f208c5 | 201 | policy->fast_switch_possible = true; |
3c429851 QP |
202 | |
203 | em_register_perf_domain(policy->cpus, nr_opp, &em_cb); | |
204 | ||
99d6bdf3 SH |
205 | return 0; |
206 | ||
99d6bdf3 SH |
207 | out_free_priv: |
208 | kfree(priv); | |
209 | out_free_opp: | |
1690d8bb | 210 | dev_pm_opp_remove_all_dynamic(cpu_dev); |
99d6bdf3 SH |
211 | |
212 | return ret; | |
213 | } | |
214 | ||
215 | static int scmi_cpufreq_exit(struct cpufreq_policy *policy) | |
216 | { | |
217 | struct scmi_data *priv = policy->driver_data; | |
218 | ||
99d6bdf3 | 219 | dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); |
1690d8bb | 220 | dev_pm_opp_remove_all_dynamic(priv->cpu_dev); |
8cbd468b | 221 | kfree(priv); |
99d6bdf3 SH |
222 | |
223 | return 0; | |
224 | } | |
225 | ||
99d6bdf3 SH |
226 | static struct cpufreq_driver scmi_cpufreq_driver = { |
227 | .name = "scmi", | |
228 | .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY | | |
5da7af9a AK |
229 | CPUFREQ_NEED_INITIAL_FREQ_CHECK | |
230 | CPUFREQ_IS_COOLING_DEV, | |
99d6bdf3 SH |
231 | .verify = cpufreq_generic_frequency_table_verify, |
232 | .attr = cpufreq_generic_attr, | |
233 | .target_index = scmi_cpufreq_set_target, | |
02f208c5 | 234 | .fast_switch = scmi_cpufreq_fast_switch, |
99d6bdf3 SH |
235 | .get = scmi_cpufreq_get_rate, |
236 | .init = scmi_cpufreq_init, | |
237 | .exit = scmi_cpufreq_exit, | |
99d6bdf3 SH |
238 | }; |
239 | ||
240 | static int scmi_cpufreq_probe(struct scmi_device *sdev) | |
241 | { | |
242 | int ret; | |
243 | ||
244 | handle = sdev->handle; | |
245 | ||
246 | if (!handle || !handle->perf_ops) | |
247 | return -ENODEV; | |
248 | ||
249 | ret = cpufreq_register_driver(&scmi_cpufreq_driver); | |
250 | if (ret) { | |
251 | dev_err(&sdev->dev, "%s: registering cpufreq failed, err: %d\n", | |
252 | __func__, ret); | |
253 | } | |
254 | ||
255 | return ret; | |
256 | } | |
257 | ||
258 | static void scmi_cpufreq_remove(struct scmi_device *sdev) | |
259 | { | |
260 | cpufreq_unregister_driver(&scmi_cpufreq_driver); | |
261 | } | |
262 | ||
263 | static const struct scmi_device_id scmi_id_table[] = { | |
12b76626 | 264 | { SCMI_PROTOCOL_PERF, "cpufreq" }, |
99d6bdf3 SH |
265 | { }, |
266 | }; | |
267 | MODULE_DEVICE_TABLE(scmi, scmi_id_table); | |
268 | ||
269 | static struct scmi_driver scmi_cpufreq_drv = { | |
270 | .name = "scmi-cpufreq", | |
271 | .probe = scmi_cpufreq_probe, | |
272 | .remove = scmi_cpufreq_remove, | |
273 | .id_table = scmi_id_table, | |
274 | }; | |
275 | module_scmi_driver(scmi_cpufreq_drv); | |
276 | ||
277 | MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); | |
278 | MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver"); | |
279 | MODULE_LICENSE("GPL v2"); |