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/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 23 struct scmi_data { 24 int domain_id; 25 struct device *cpu_dev; 26 }; 27 28 static const struct scmi_handle *handle; 29 30 static unsigned int scmi_cpufreq_get_rate(unsigned int cpu) 31 { 32 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); 33 const 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 */ 49 static int 50 scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index) 51 { 52 struct scmi_data *priv = policy->driver_data; 53 const struct scmi_perf_ops *perf_ops = handle->perf_ops; 54 u64 freq = policy->freq_table[index].frequency; 55 56 return perf_ops->freq_set(handle, priv->domain_id, freq * 1000, false); 57 } 58 59 static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy, 60 unsigned int target_freq) 61 { 62 struct scmi_data *priv = policy->driver_data; 63 const struct scmi_perf_ops *perf_ops = handle->perf_ops; 64 65 if (!perf_ops->freq_set(handle, priv->domain_id, 66 target_freq * 1000, true)) 67 return target_freq; 68 69 return 0; 70 } 71 72 static int 73 scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask) 74 { 75 int cpu, domain, tdomain; 76 struct device *tcpu_dev; 77 78 domain = handle->perf_ops->device_domain_id(cpu_dev); 79 if (domain < 0) 80 return domain; 81 82 for_each_possible_cpu(cpu) { 83 if (cpu == cpu_dev->id) 84 continue; 85 86 tcpu_dev = get_cpu_device(cpu); 87 if (!tcpu_dev) 88 continue; 89 90 tdomain = handle->perf_ops->device_domain_id(tcpu_dev); 91 if (tdomain == domain) 92 cpumask_set_cpu(cpu, cpumask); 93 } 94 95 return 0; 96 } 97 98 static int __maybe_unused 99 scmi_get_cpu_power(unsigned long *power, unsigned long *KHz, 100 struct device *cpu_dev) 101 { 102 unsigned long Hz; 103 int ret, domain; 104 105 domain = handle->perf_ops->device_domain_id(cpu_dev); 106 if (domain < 0) 107 return domain; 108 109 /* Get the power cost of the performance domain. */ 110 Hz = *KHz * 1000; 111 ret = handle->perf_ops->est_power_get(handle, domain, &Hz, power); 112 if (ret) 113 return ret; 114 115 /* The EM framework specifies the frequency in KHz. */ 116 *KHz = Hz / 1000; 117 118 return 0; 119 } 120 121 static int scmi_cpufreq_init(struct cpufreq_policy *policy) 122 { 123 int ret, nr_opp; 124 unsigned int latency; 125 struct device *cpu_dev; 126 struct scmi_data *priv; 127 struct cpufreq_frequency_table *freq_table; 128 struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power); 129 bool power_scale_mw; 130 131 cpu_dev = get_cpu_device(policy->cpu); 132 if (!cpu_dev) { 133 pr_err("failed to get cpu%d device\n", policy->cpu); 134 return -ENODEV; 135 } 136 137 ret = handle->perf_ops->device_opps_add(handle, cpu_dev); 138 if (ret) { 139 dev_warn(cpu_dev, "failed to add opps to the device\n"); 140 return ret; 141 } 142 143 ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus); 144 if (ret) { 145 dev_warn(cpu_dev, "failed to get sharing cpumask\n"); 146 return ret; 147 } 148 149 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus); 150 if (ret) { 151 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", 152 __func__, ret); 153 return ret; 154 } 155 156 nr_opp = dev_pm_opp_get_opp_count(cpu_dev); 157 if (nr_opp <= 0) { 158 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); 159 ret = -EPROBE_DEFER; 160 goto out_free_opp; 161 } 162 163 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 164 if (!priv) { 165 ret = -ENOMEM; 166 goto out_free_opp; 167 } 168 169 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); 170 if (ret) { 171 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret); 172 goto out_free_priv; 173 } 174 175 priv->cpu_dev = cpu_dev; 176 priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev); 177 178 policy->driver_data = priv; 179 policy->freq_table = freq_table; 180 181 /* SCMI allows DVFS request for any domain from any CPU */ 182 policy->dvfs_possible_from_any_cpu = true; 183 184 latency = handle->perf_ops->transition_latency_get(handle, cpu_dev); 185 if (!latency) 186 latency = CPUFREQ_ETERNAL; 187 188 policy->cpuinfo.transition_latency = latency; 189 190 policy->fast_switch_possible = 191 handle->perf_ops->fast_switch_possible(handle, cpu_dev); 192 193 power_scale_mw = handle->perf_ops->power_scale_mw_get(handle); 194 em_dev_register_perf_domain(cpu_dev, nr_opp, &em_cb, policy->cpus, 195 power_scale_mw); 196 197 return 0; 198 199 out_free_priv: 200 kfree(priv); 201 out_free_opp: 202 dev_pm_opp_remove_all_dynamic(cpu_dev); 203 204 return ret; 205 } 206 207 static int scmi_cpufreq_exit(struct cpufreq_policy *policy) 208 { 209 struct scmi_data *priv = policy->driver_data; 210 211 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); 212 dev_pm_opp_remove_all_dynamic(priv->cpu_dev); 213 kfree(priv); 214 215 return 0; 216 } 217 218 static struct cpufreq_driver scmi_cpufreq_driver = { 219 .name = "scmi", 220 .flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY | 221 CPUFREQ_NEED_INITIAL_FREQ_CHECK | 222 CPUFREQ_IS_COOLING_DEV, 223 .verify = cpufreq_generic_frequency_table_verify, 224 .attr = cpufreq_generic_attr, 225 .target_index = scmi_cpufreq_set_target, 226 .fast_switch = scmi_cpufreq_fast_switch, 227 .get = scmi_cpufreq_get_rate, 228 .init = scmi_cpufreq_init, 229 .exit = scmi_cpufreq_exit, 230 }; 231 232 static int scmi_cpufreq_probe(struct scmi_device *sdev) 233 { 234 int ret; 235 struct device *dev = &sdev->dev; 236 237 handle = sdev->handle; 238 239 if (!handle || !handle->perf_ops) 240 return -ENODEV; 241 242 #ifdef CONFIG_COMMON_CLK 243 /* dummy clock provider as needed by OPP if clocks property is used */ 244 if (of_find_property(dev->of_node, "#clock-cells", NULL)) 245 devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, NULL); 246 #endif 247 248 ret = cpufreq_register_driver(&scmi_cpufreq_driver); 249 if (ret) { 250 dev_err(dev, "%s: registering cpufreq failed, err: %d\n", 251 __func__, ret); 252 } 253 254 return ret; 255 } 256 257 static void scmi_cpufreq_remove(struct scmi_device *sdev) 258 { 259 cpufreq_unregister_driver(&scmi_cpufreq_driver); 260 } 261 262 static const struct scmi_device_id scmi_id_table[] = { 263 { SCMI_PROTOCOL_PERF, "cpufreq" }, 264 { }, 265 }; 266 MODULE_DEVICE_TABLE(scmi, scmi_id_table); 267 268 static struct scmi_driver scmi_cpufreq_drv = { 269 .name = "scmi-cpufreq", 270 .probe = scmi_cpufreq_probe, 271 .remove = scmi_cpufreq_remove, 272 .id_table = scmi_id_table, 273 }; 274 module_scmi_driver(scmi_cpufreq_drv); 275 276 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); 277 MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver"); 278 MODULE_LICENSE("GPL v2"); 279