2 * System Control and Power Interface (SCPI) based CPUFreq Interface driver
4 * It provides necessary ops to arm_big_little cpufreq driver.
6 * Copyright (C) 2015 ARM Ltd.
7 * Sudeep Holla <sudeep.holla@arm.com>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
13 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
14 * kind, whether express or implied; without even the implied warranty
15 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 #include <linux/clk.h>
22 #include <linux/cpu.h>
23 #include <linux/cpufreq.h>
24 #include <linux/cpumask.h>
25 #include <linux/cpu_cooling.h>
26 #include <linux/export.h>
27 #include <linux/module.h>
28 #include <linux/of_platform.h>
29 #include <linux/pm_opp.h>
30 #include <linux/scpi_protocol.h>
31 #include <linux/slab.h>
32 #include <linux/types.h>
36 struct device *cpu_dev;
37 struct thermal_cooling_device *cdev;
40 static struct scpi_ops *scpi_ops;
42 static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
44 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
45 struct scpi_data *priv = policy->driver_data;
46 unsigned long rate = clk_get_rate(priv->clk);
52 scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
54 struct scpi_data *priv = policy->driver_data;
55 u64 rate = policy->freq_table[index].frequency * 1000;
58 ret = clk_set_rate(priv->clk, rate);
59 if (!ret && (clk_get_rate(priv->clk) != rate))
66 scpi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
68 int cpu, domain, tdomain;
69 struct device *tcpu_dev;
71 domain = scpi_ops->device_domain_id(cpu_dev);
75 for_each_possible_cpu(cpu) {
76 if (cpu == cpu_dev->id)
79 tcpu_dev = get_cpu_device(cpu);
83 tdomain = scpi_ops->device_domain_id(tcpu_dev);
84 if (tdomain == domain)
85 cpumask_set_cpu(cpu, cpumask);
91 static int scpi_cpufreq_init(struct cpufreq_policy *policy)
95 struct device *cpu_dev;
96 struct scpi_data *priv;
97 struct cpufreq_frequency_table *freq_table;
99 cpu_dev = get_cpu_device(policy->cpu);
101 pr_err("failed to get cpu%d device\n", policy->cpu);
105 ret = scpi_ops->add_opps_to_device(cpu_dev);
107 dev_warn(cpu_dev, "failed to add opps to the device\n");
111 ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus);
113 dev_warn(cpu_dev, "failed to get sharing cpumask\n");
117 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
119 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
124 ret = dev_pm_opp_get_opp_count(cpu_dev);
126 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
131 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
137 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
139 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
143 priv->cpu_dev = cpu_dev;
144 priv->clk = clk_get(cpu_dev, NULL);
145 if (IS_ERR(priv->clk)) {
146 dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n",
147 __func__, cpu_dev->id);
148 goto out_free_cpufreq_table;
151 policy->driver_data = priv;
153 ret = cpufreq_table_validate_and_show(policy, freq_table);
155 dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
160 /* scpi allows DVFS request for any domain from any CPU */
161 policy->dvfs_possible_from_any_cpu = true;
163 latency = scpi_ops->get_transition_latency(cpu_dev);
165 latency = CPUFREQ_ETERNAL;
167 policy->cpuinfo.transition_latency = latency;
169 policy->fast_switch_possible = false;
174 out_free_cpufreq_table:
175 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
179 dev_pm_opp_cpumask_remove_table(policy->cpus);
184 static int scpi_cpufreq_exit(struct cpufreq_policy *policy)
186 struct scpi_data *priv = policy->driver_data;
188 cpufreq_cooling_unregister(priv->cdev);
190 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
192 dev_pm_opp_cpumask_remove_table(policy->related_cpus);
197 static void scpi_cpufreq_ready(struct cpufreq_policy *policy)
199 struct scpi_data *priv = policy->driver_data;
200 struct thermal_cooling_device *cdev;
202 cdev = of_cpufreq_cooling_register(policy);
207 static struct cpufreq_driver scpi_cpufreq_driver = {
208 .name = "scpi-cpufreq",
209 .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
210 CPUFREQ_NEED_INITIAL_FREQ_CHECK,
211 .verify = cpufreq_generic_frequency_table_verify,
212 .attr = cpufreq_generic_attr,
213 .get = scpi_cpufreq_get_rate,
214 .init = scpi_cpufreq_init,
215 .exit = scpi_cpufreq_exit,
216 .ready = scpi_cpufreq_ready,
217 .target_index = scpi_cpufreq_set_target,
220 static int scpi_cpufreq_probe(struct platform_device *pdev)
224 scpi_ops = get_scpi_ops();
228 ret = cpufreq_register_driver(&scpi_cpufreq_driver);
230 dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n",
235 static int scpi_cpufreq_remove(struct platform_device *pdev)
237 cpufreq_unregister_driver(&scpi_cpufreq_driver);
242 static struct platform_driver scpi_cpufreq_platdrv = {
244 .name = "scpi-cpufreq",
246 .probe = scpi_cpufreq_probe,
247 .remove = scpi_cpufreq_remove,
249 module_platform_driver(scpi_cpufreq_platdrv);
251 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
252 MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
253 MODULE_LICENSE("GPL v2");