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279 lines
6.7 KiB
C
279 lines
6.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* System Control and Power Interface (SCMI) based CPUFreq Interface driver
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*
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* Copyright (C) 2018 ARM Ltd.
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* Sudeep Holla <sudeep.holla@arm.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/clk-provider.h>
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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/cpumask.h>
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#include <linux/energy_model.h>
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#include <linux/export.h>
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#include <linux/module.h>
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#include <linux/pm_opp.h>
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#include <linux/slab.h>
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#include <linux/scmi_protocol.h>
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#include <linux/types.h>
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struct scmi_data {
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int domain_id;
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struct device *cpu_dev;
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};
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static const struct scmi_handle *handle;
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static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
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{
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struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
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const struct scmi_perf_ops *perf_ops = handle->perf_ops;
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struct scmi_data *priv = policy->driver_data;
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unsigned long rate;
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int ret;
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ret = perf_ops->freq_get(handle, priv->domain_id, &rate, false);
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if (ret)
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return 0;
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return rate / 1000;
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}
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/*
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* perf_ops->freq_set is not a synchronous, the actual OPP change will
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* happen asynchronously and can get notified if the events are
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* subscribed for by the SCMI firmware
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*/
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static int
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scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
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{
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struct scmi_data *priv = policy->driver_data;
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const struct scmi_perf_ops *perf_ops = handle->perf_ops;
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u64 freq = policy->freq_table[index].frequency;
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return perf_ops->freq_set(handle, priv->domain_id, freq * 1000, false);
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}
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static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
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unsigned int target_freq)
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{
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struct scmi_data *priv = policy->driver_data;
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const struct scmi_perf_ops *perf_ops = handle->perf_ops;
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if (!perf_ops->freq_set(handle, priv->domain_id,
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target_freq * 1000, true))
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return target_freq;
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return 0;
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}
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static int
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scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
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{
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int cpu, domain, tdomain;
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struct device *tcpu_dev;
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domain = handle->perf_ops->device_domain_id(cpu_dev);
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if (domain < 0)
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return domain;
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for_each_possible_cpu(cpu) {
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if (cpu == cpu_dev->id)
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continue;
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tcpu_dev = get_cpu_device(cpu);
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if (!tcpu_dev)
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continue;
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tdomain = handle->perf_ops->device_domain_id(tcpu_dev);
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if (tdomain == domain)
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cpumask_set_cpu(cpu, cpumask);
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}
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return 0;
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}
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static int __maybe_unused
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scmi_get_cpu_power(unsigned long *power, unsigned long *KHz,
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struct device *cpu_dev)
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{
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unsigned long Hz;
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int ret, domain;
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domain = handle->perf_ops->device_domain_id(cpu_dev);
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if (domain < 0)
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return domain;
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/* Get the power cost of the performance domain. */
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Hz = *KHz * 1000;
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ret = handle->perf_ops->est_power_get(handle, domain, &Hz, power);
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if (ret)
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return ret;
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/* The EM framework specifies the frequency in KHz. */
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*KHz = Hz / 1000;
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return 0;
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}
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static int scmi_cpufreq_init(struct cpufreq_policy *policy)
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{
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int ret, nr_opp;
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unsigned int latency;
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struct device *cpu_dev;
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struct scmi_data *priv;
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struct cpufreq_frequency_table *freq_table;
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struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
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bool power_scale_mw;
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cpu_dev = get_cpu_device(policy->cpu);
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if (!cpu_dev) {
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pr_err("failed to get cpu%d device\n", policy->cpu);
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return -ENODEV;
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}
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ret = handle->perf_ops->device_opps_add(handle, cpu_dev);
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if (ret) {
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dev_warn(cpu_dev, "failed to add opps to the device\n");
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return ret;
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}
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ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
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if (ret) {
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dev_warn(cpu_dev, "failed to get sharing cpumask\n");
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return ret;
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}
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ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
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if (ret) {
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dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
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__func__, ret);
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return ret;
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}
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nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
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if (nr_opp <= 0) {
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dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
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ret = -EPROBE_DEFER;
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goto out_free_opp;
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}
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv) {
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ret = -ENOMEM;
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goto out_free_opp;
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}
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ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
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if (ret) {
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dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
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goto out_free_priv;
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}
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priv->cpu_dev = cpu_dev;
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priv->domain_id = handle->perf_ops->device_domain_id(cpu_dev);
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policy->driver_data = priv;
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policy->freq_table = freq_table;
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/* SCMI allows DVFS request for any domain from any CPU */
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policy->dvfs_possible_from_any_cpu = true;
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latency = handle->perf_ops->transition_latency_get(handle, cpu_dev);
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if (!latency)
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latency = CPUFREQ_ETERNAL;
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policy->cpuinfo.transition_latency = latency;
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policy->fast_switch_possible =
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handle->perf_ops->fast_switch_possible(handle, cpu_dev);
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power_scale_mw = handle->perf_ops->power_scale_mw_get(handle);
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em_dev_register_perf_domain(cpu_dev, nr_opp, &em_cb, policy->cpus,
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power_scale_mw);
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return 0;
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out_free_priv:
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kfree(priv);
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out_free_opp:
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dev_pm_opp_remove_all_dynamic(cpu_dev);
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return ret;
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}
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static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
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{
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struct scmi_data *priv = policy->driver_data;
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dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
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dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
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kfree(priv);
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return 0;
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}
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static struct cpufreq_driver scmi_cpufreq_driver = {
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.name = "scmi",
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.flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
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CPUFREQ_NEED_INITIAL_FREQ_CHECK |
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CPUFREQ_IS_COOLING_DEV,
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.verify = cpufreq_generic_frequency_table_verify,
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.attr = cpufreq_generic_attr,
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.target_index = scmi_cpufreq_set_target,
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.fast_switch = scmi_cpufreq_fast_switch,
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.get = scmi_cpufreq_get_rate,
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.init = scmi_cpufreq_init,
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.exit = scmi_cpufreq_exit,
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};
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static int scmi_cpufreq_probe(struct scmi_device *sdev)
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{
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int ret;
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struct device *dev = &sdev->dev;
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handle = sdev->handle;
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if (!handle || !handle->perf_ops)
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return -ENODEV;
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#ifdef CONFIG_COMMON_CLK
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/* dummy clock provider as needed by OPP if clocks property is used */
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if (of_find_property(dev->of_node, "#clock-cells", NULL))
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devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, NULL);
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#endif
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ret = cpufreq_register_driver(&scmi_cpufreq_driver);
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if (ret) {
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dev_err(dev, "%s: registering cpufreq failed, err: %d\n",
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__func__, ret);
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}
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return ret;
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}
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static void scmi_cpufreq_remove(struct scmi_device *sdev)
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{
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cpufreq_unregister_driver(&scmi_cpufreq_driver);
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}
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static const struct scmi_device_id scmi_id_table[] = {
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{ SCMI_PROTOCOL_PERF, "cpufreq" },
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{ },
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};
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MODULE_DEVICE_TABLE(scmi, scmi_id_table);
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static struct scmi_driver scmi_cpufreq_drv = {
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.name = "scmi-cpufreq",
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.probe = scmi_cpufreq_probe,
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.remove = scmi_cpufreq_remove,
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.id_table = scmi_id_table,
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};
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module_scmi_driver(scmi_cpufreq_drv);
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MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
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MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
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MODULE_LICENSE("GPL v2");
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