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1// SPDX-License-Identifier: GPL-2.02/*3 * System Control and Power Interface (SCMI) based CPUFreq Interface driver4 *5 * Copyright (C) 2018-2021 ARM Ltd.6 * Sudeep Holla <sudeep.holla@arm.com>7 */8 9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt10 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;33static struct cpufreq_driver scmi_cpufreq_driver;34 35static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)36{37 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);38 struct scmi_data *priv = policy->driver_data;39 unsigned long rate;40 int ret;41 42 ret = perf_ops->freq_get(ph, priv->domain_id, &rate, false);43 if (ret)44 return 0;45 return rate / 1000;46}47 48/*49 * perf_ops->freq_set is not a synchronous, the actual OPP change will50 * happen asynchronously and can get notified if the events are51 * subscribed for by the SCMI firmware52 */53static int54scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)55{56 struct scmi_data *priv = policy->driver_data;57 u64 freq = policy->freq_table[index].frequency;58 59 return perf_ops->freq_set(ph, priv->domain_id, freq * 1000, false);60}61 62static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,63 unsigned int target_freq)64{65 struct scmi_data *priv = policy->driver_data;66 unsigned long freq = target_freq;67 68 if (!perf_ops->freq_set(ph, priv->domain_id, freq * 1000, true))69 return target_freq;70 71 return 0;72}73 74static int scmi_cpu_domain_id(struct device *cpu_dev)75{76 struct device_node *np = cpu_dev->of_node;77 struct of_phandle_args domain_id;78 int index;79 80 if (of_parse_phandle_with_args(np, "clocks", "#clock-cells", 0,81 &domain_id)) {82 /* Find the corresponding index for power-domain "perf". */83 index = of_property_match_string(np, "power-domain-names",84 "perf");85 if (index < 0)86 return -EINVAL;87 88 if (of_parse_phandle_with_args(np, "power-domains",89 "#power-domain-cells", index,90 &domain_id))91 return -EINVAL;92 }93 94 return domain_id.args[0];95}96 97static int98scmi_get_sharing_cpus(struct device *cpu_dev, int domain,99 struct cpumask *cpumask)100{101 int cpu, tdomain;102 struct device *tcpu_dev;103 104 for_each_possible_cpu(cpu) {105 if (cpu == cpu_dev->id)106 continue;107 108 tcpu_dev = get_cpu_device(cpu);109 if (!tcpu_dev)110 continue;111 112 tdomain = scmi_cpu_domain_id(tcpu_dev);113 if (tdomain == domain)114 cpumask_set_cpu(cpu, cpumask);115 }116 117 return 0;118}119 120static int __maybe_unused121scmi_get_cpu_power(struct device *cpu_dev, unsigned long *power,122 unsigned long *KHz)123{124 enum scmi_power_scale power_scale = perf_ops->power_scale_get(ph);125 unsigned long Hz;126 int ret, domain;127 128 domain = scmi_cpu_domain_id(cpu_dev);129 if (domain < 0)130 return domain;131 132 /* Get the power cost of the performance domain. */133 Hz = *KHz * 1000;134 ret = perf_ops->est_power_get(ph, domain, &Hz, power);135 if (ret)136 return ret;137 138 /* Convert the power to uW if it is mW (ignore bogoW) */139 if (power_scale == SCMI_POWER_MILLIWATTS)140 *power *= MICROWATT_PER_MILLIWATT;141 142 /* The EM framework specifies the frequency in KHz. */143 *KHz = Hz / 1000;144 145 return 0;146}147 148static int149scmi_get_rate_limit(u32 domain, bool has_fast_switch)150{151 int ret, rate_limit;152 153 if (has_fast_switch) {154 /*155 * Fast channels are used whenever available,156 * so use their rate_limit value if populated.157 */158 ret = perf_ops->fast_switch_rate_limit(ph, domain,159 &rate_limit);160 if (!ret && rate_limit)161 return rate_limit;162 }163 164 ret = perf_ops->rate_limit_get(ph, domain, &rate_limit);165 if (ret)166 return 0;167 168 return rate_limit;169}170 171static struct freq_attr *scmi_cpufreq_hw_attr[] = {172 &cpufreq_freq_attr_scaling_available_freqs,173 NULL,174 NULL,175};176 177static int scmi_cpufreq_init(struct cpufreq_policy *policy)178{179 int ret, nr_opp, domain;180 unsigned int latency;181 struct device *cpu_dev;182 struct scmi_data *priv;183 struct cpufreq_frequency_table *freq_table;184 185 cpu_dev = get_cpu_device(policy->cpu);186 if (!cpu_dev) {187 pr_err("failed to get cpu%d device\n", policy->cpu);188 return -ENODEV;189 }190 191 domain = scmi_cpu_domain_id(cpu_dev);192 if (domain < 0)193 return domain;194 195 priv = kzalloc(sizeof(*priv), GFP_KERNEL);196 if (!priv)197 return -ENOMEM;198 199 if (!zalloc_cpumask_var(&priv->opp_shared_cpus, GFP_KERNEL)) {200 ret = -ENOMEM;201 goto out_free_priv;202 }203 204 /* Obtain CPUs that share SCMI performance controls */205 ret = scmi_get_sharing_cpus(cpu_dev, domain, policy->cpus);206 if (ret) {207 dev_warn(cpu_dev, "failed to get sharing cpumask\n");208 goto out_free_cpumask;209 }210 211 /*212 * Obtain CPUs that share performance levels.213 * The OPP 'sharing cpus' info may come from DT through an empty opp214 * table and opp-shared.215 */216 ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->opp_shared_cpus);217 if (ret || cpumask_empty(priv->opp_shared_cpus)) {218 /*219 * Either opp-table is not set or no opp-shared was found.220 * Use the CPU mask from SCMI to designate CPUs sharing an OPP221 * table.222 */223 cpumask_copy(priv->opp_shared_cpus, policy->cpus);224 }225 226 /*227 * A previous CPU may have marked OPPs as shared for a few CPUs, based on228 * what OPP core provided. If the current CPU is part of those few, then229 * there is no need to add OPPs again.230 */231 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);232 if (nr_opp <= 0) {233 ret = perf_ops->device_opps_add(ph, cpu_dev, domain);234 if (ret) {235 dev_warn(cpu_dev, "failed to add opps to the device\n");236 goto out_free_cpumask;237 }238 239 nr_opp = dev_pm_opp_get_opp_count(cpu_dev);240 if (nr_opp <= 0) {241 dev_err(cpu_dev, "%s: No OPPs for this device: %d\n",242 __func__, nr_opp);243 244 ret = -ENODEV;245 goto out_free_opp;246 }247 248 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->opp_shared_cpus);249 if (ret) {250 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",251 __func__, ret);252 253 goto out_free_opp;254 }255 256 priv->nr_opp = nr_opp;257 }258 259 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);260 if (ret) {261 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);262 goto out_free_opp;263 }264 265 priv->cpu_dev = cpu_dev;266 priv->domain_id = domain;267 268 policy->driver_data = priv;269 policy->freq_table = freq_table;270 271 /* SCMI allows DVFS request for any domain from any CPU */272 policy->dvfs_possible_from_any_cpu = true;273 274 latency = perf_ops->transition_latency_get(ph, domain);275 if (!latency)276 latency = CPUFREQ_ETERNAL;277 278 policy->cpuinfo.transition_latency = latency;279 280 policy->fast_switch_possible =281 perf_ops->fast_switch_possible(ph, domain);282 283 policy->transition_delay_us =284 scmi_get_rate_limit(domain, policy->fast_switch_possible);285 286 if (policy_has_boost_freq(policy)) {287 ret = cpufreq_enable_boost_support();288 if (ret) {289 dev_warn(cpu_dev, "failed to enable boost: %d\n", ret);290 goto out_free_opp;291 } else {292 scmi_cpufreq_hw_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;293 scmi_cpufreq_driver.boost_enabled = true;294 }295 }296 297 return 0;298 299out_free_opp:300 dev_pm_opp_remove_all_dynamic(cpu_dev);301 302out_free_cpumask:303 free_cpumask_var(priv->opp_shared_cpus);304 305out_free_priv:306 kfree(priv);307 308 return ret;309}310 311static void scmi_cpufreq_exit(struct cpufreq_policy *policy)312{313 struct scmi_data *priv = policy->driver_data;314 315 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);316 dev_pm_opp_remove_all_dynamic(priv->cpu_dev);317 free_cpumask_var(priv->opp_shared_cpus);318 kfree(priv);319}320 321static void scmi_cpufreq_register_em(struct cpufreq_policy *policy)322{323 struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);324 enum scmi_power_scale power_scale = perf_ops->power_scale_get(ph);325 struct scmi_data *priv = policy->driver_data;326 bool em_power_scale = false;327 328 /*329 * This callback will be called for each policy, but we don't need to330 * register with EM every time. Despite not being part of the same331 * policy, some CPUs may still share their perf-domains, and a CPU from332 * another policy may already have registered with EM on behalf of CPUs333 * of this policy.334 */335 if (!priv->nr_opp)336 return;337 338 if (power_scale == SCMI_POWER_MILLIWATTS339 || power_scale == SCMI_POWER_MICROWATTS)340 em_power_scale = true;341 342 em_dev_register_perf_domain(get_cpu_device(policy->cpu), priv->nr_opp,343 &em_cb, priv->opp_shared_cpus,344 em_power_scale);345}346 347static struct cpufreq_driver scmi_cpufreq_driver = {348 .name = "scmi",349 .flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |350 CPUFREQ_NEED_INITIAL_FREQ_CHECK |351 CPUFREQ_IS_COOLING_DEV,352 .verify = cpufreq_generic_frequency_table_verify,353 .attr = scmi_cpufreq_hw_attr,354 .target_index = scmi_cpufreq_set_target,355 .fast_switch = scmi_cpufreq_fast_switch,356 .get = scmi_cpufreq_get_rate,357 .init = scmi_cpufreq_init,358 .exit = scmi_cpufreq_exit,359 .register_em = scmi_cpufreq_register_em,360};361 362static int scmi_cpufreq_probe(struct scmi_device *sdev)363{364 int ret;365 struct device *dev = &sdev->dev;366 const struct scmi_handle *handle;367 368 handle = sdev->handle;369 370 if (!handle)371 return -ENODEV;372 373 perf_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_PERF, &ph);374 if (IS_ERR(perf_ops))375 return PTR_ERR(perf_ops);376 377#ifdef CONFIG_COMMON_CLK378 /* dummy clock provider as needed by OPP if clocks property is used */379 if (of_property_present(dev->of_node, "#clock-cells")) {380 ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, NULL);381 if (ret)382 return dev_err_probe(dev, ret, "%s: registering clock provider failed\n", __func__);383 }384#endif385 386 ret = cpufreq_register_driver(&scmi_cpufreq_driver);387 if (ret) {388 dev_err(dev, "%s: registering cpufreq failed, err: %d\n",389 __func__, ret);390 }391 392 return ret;393}394 395static void scmi_cpufreq_remove(struct scmi_device *sdev)396{397 cpufreq_unregister_driver(&scmi_cpufreq_driver);398}399 400static const struct scmi_device_id scmi_id_table[] = {401 { SCMI_PROTOCOL_PERF, "cpufreq" },402 { },403};404MODULE_DEVICE_TABLE(scmi, scmi_id_table);405 406static struct scmi_driver scmi_cpufreq_drv = {407 .name = "scmi-cpufreq",408 .probe = scmi_cpufreq_probe,409 .remove = scmi_cpufreq_remove,410 .id_table = scmi_id_table,411};412module_scmi_driver(scmi_cpufreq_drv);413 414MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");415MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");416MODULE_LICENSE("GPL v2");417