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 22 struct scmi_data { 23 int domain_id; 24 struct device *cpu_dev; 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; 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 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 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 } 104 105 static int __maybe_unused 106 scmi_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 } 127 128 static 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 = true; 197 198 em_dev_register_perf_domain(cpu_dev, nr_opp, &em_cb, policy->cpus); 199 200 return 0; 201 202 out_free_priv: 203 kfree(priv); 204 out_free_opp: 205 dev_pm_opp_remove_all_dynamic(cpu_dev); 206 207 return ret; 208 } 209 210 static int scmi_cpufreq_exit(struct cpufreq_policy *policy) 211 { 212 struct scmi_data *priv = policy->driver_data; 213 214 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); 215 dev_pm_opp_remove_all_dynamic(priv->cpu_dev); 216 kfree(priv); 217 218 return 0; 219 } 220 221 static struct cpufreq_driver scmi_cpufreq_driver = { 222 .name = "scmi", 223 .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY | 224 CPUFREQ_NEED_INITIAL_FREQ_CHECK | 225 CPUFREQ_IS_COOLING_DEV, 226 .verify = cpufreq_generic_frequency_table_verify, 227 .attr = cpufreq_generic_attr, 228 .target_index = scmi_cpufreq_set_target, 229 .fast_switch = scmi_cpufreq_fast_switch, 230 .get = scmi_cpufreq_get_rate, 231 .init = scmi_cpufreq_init, 232 .exit = scmi_cpufreq_exit, 233 }; 234 235 static int scmi_cpufreq_probe(struct scmi_device *sdev) 236 { 237 int ret; 238 239 handle = sdev->handle; 240 241 if (!handle || !handle->perf_ops) 242 return -ENODEV; 243 244 ret = cpufreq_register_driver(&scmi_cpufreq_driver); 245 if (ret) { 246 dev_err(&sdev->dev, "%s: registering cpufreq failed, err: %d\n", 247 __func__, ret); 248 } 249 250 return ret; 251 } 252 253 static void scmi_cpufreq_remove(struct scmi_device *sdev) 254 { 255 cpufreq_unregister_driver(&scmi_cpufreq_driver); 256 } 257 258 static const struct scmi_device_id scmi_id_table[] = { 259 { SCMI_PROTOCOL_PERF, "cpufreq" }, 260 { }, 261 }; 262 MODULE_DEVICE_TABLE(scmi, scmi_id_table); 263 264 static struct scmi_driver scmi_cpufreq_drv = { 265 .name = "scmi-cpufreq", 266 .probe = scmi_cpufreq_probe, 267 .remove = scmi_cpufreq_remove, 268 .id_table = scmi_id_table, 269 }; 270 module_scmi_driver(scmi_cpufreq_drv); 271 272 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); 273 MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver"); 274 MODULE_LICENSE("GPL v2"); 275