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); 129 130 cpu_dev = get_cpu_device(policy->cpu); 131 if (!cpu_dev) { 132 pr_err("failed to get cpu%d device\n", policy->cpu); 133 return -ENODEV; 134 } 135 136 ret = handle->perf_ops->device_opps_add(handle, cpu_dev); 137 if (ret) { 138 dev_warn(cpu_dev, "failed to add opps to the device\n"); 139 return ret; 140 } 141 142 ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus); 143 if (ret) { 144 dev_warn(cpu_dev, "failed to get sharing cpumask\n"); 145 return ret; 146 } 147 148 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus); 149 if (ret) { 150 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", 151 __func__, ret); 152 return ret; 153 } 154 155 nr_opp = dev_pm_opp_get_opp_count(cpu_dev); 156 if (nr_opp <= 0) { 157 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); 158 ret = -EPROBE_DEFER; 159 goto out_free_opp; 160 } 161 162 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 163 if (!priv) { 164 ret = -ENOMEM; 165 goto out_free_opp; 166 } 167 168 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); 169 if (ret) { 170 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret); 171 goto out_free_priv; 172 } 173 174 priv->cpu_dev = cpu_dev; 175 priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev); 176 177 policy->driver_data = priv; 178 policy->freq_table = freq_table; 179 180 /* SCMI allows DVFS request for any domain from any CPU */ 181 policy->dvfs_possible_from_any_cpu = true; 182 183 latency = handle->perf_ops->transition_latency_get(handle, cpu_dev); 184 if (!latency) 185 latency = CPUFREQ_ETERNAL; 186 187 policy->cpuinfo.transition_latency = latency; 188 189 policy->fast_switch_possible = 190 handle->perf_ops->fast_switch_possible(handle, cpu_dev); 191 192 em_dev_register_perf_domain(cpu_dev, nr_opp, &em_cb, policy->cpus); 193 194 return 0; 195 196 out_free_priv: 197 kfree(priv); 198 out_free_opp: 199 dev_pm_opp_remove_all_dynamic(cpu_dev); 200 201 return ret; 202 } 203 204 static int scmi_cpufreq_exit(struct cpufreq_policy *policy) 205 { 206 struct scmi_data *priv = policy->driver_data; 207 208 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); 209 dev_pm_opp_remove_all_dynamic(priv->cpu_dev); 210 kfree(priv); 211 212 return 0; 213 } 214 215 static struct cpufreq_driver scmi_cpufreq_driver = { 216 .name = "scmi", 217 .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY | 218 CPUFREQ_NEED_INITIAL_FREQ_CHECK | 219 CPUFREQ_IS_COOLING_DEV, 220 .verify = cpufreq_generic_frequency_table_verify, 221 .attr = cpufreq_generic_attr, 222 .target_index = scmi_cpufreq_set_target, 223 .fast_switch = scmi_cpufreq_fast_switch, 224 .get = scmi_cpufreq_get_rate, 225 .init = scmi_cpufreq_init, 226 .exit = scmi_cpufreq_exit, 227 }; 228 229 static int scmi_cpufreq_probe(struct scmi_device *sdev) 230 { 231 int ret; 232 struct device *dev = &sdev->dev; 233 234 handle = sdev->handle; 235 236 if (!handle || !handle->perf_ops) 237 return -ENODEV; 238 239 #ifdef CONFIG_COMMON_CLK 240 /* dummy clock provider as needed by OPP if clocks property is used */ 241 if (of_find_property(dev->of_node, "#clock-cells", NULL)) 242 devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, NULL); 243 #endif 244 245 ret = cpufreq_register_driver(&scmi_cpufreq_driver); 246 if (ret) { 247 dev_err(dev, "%s: registering cpufreq failed, err: %d\n", 248 __func__, ret); 249 } 250 251 return ret; 252 } 253 254 static void scmi_cpufreq_remove(struct scmi_device *sdev) 255 { 256 cpufreq_unregister_driver(&scmi_cpufreq_driver); 257 } 258 259 static const struct scmi_device_id scmi_id_table[] = { 260 { SCMI_PROTOCOL_PERF, "cpufreq" }, 261 { }, 262 }; 263 MODULE_DEVICE_TABLE(scmi, scmi_id_table); 264 265 static 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 }; 271 module_scmi_driver(scmi_cpufreq_drv); 272 273 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); 274 MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver"); 275 MODULE_LICENSE("GPL v2"); 276