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17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19#include <linux/clk.h>
20#include <linux/cpu.h>
21#include <linux/cpufreq.h>
22#include <linux/cpumask.h>
23#include <linux/export.h>
24#include <linux/module.h>
25#include <linux/of_platform.h>
26#include <linux/pm_opp.h>
27#include <linux/scpi_protocol.h>
28#include <linux/slab.h>
29#include <linux/types.h>
30
31struct scpi_data {
32 struct clk *clk;
33 struct device *cpu_dev;
34};
35
36static struct scpi_ops *scpi_ops;
37
38static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
39{
40 struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
41 struct scpi_data *priv = policy->driver_data;
42 unsigned long rate = clk_get_rate(priv->clk);
43
44 return rate / 1000;
45}
46
47static int
48scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
49{
50 u64 rate = policy->freq_table[index].frequency * 1000;
51 struct scpi_data *priv = policy->driver_data;
52 int ret;
53
54 ret = clk_set_rate(priv->clk, rate);
55
56 if (ret)
57 return ret;
58
59 if (clk_get_rate(priv->clk) != rate)
60 return -EIO;
61
62 return 0;
63}
64
65static int
66scpi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
67{
68 int cpu, domain, tdomain;
69 struct device *tcpu_dev;
70
71 domain = scpi_ops->device_domain_id(cpu_dev);
72 if (domain < 0)
73 return domain;
74
75 for_each_possible_cpu(cpu) {
76 if (cpu == cpu_dev->id)
77 continue;
78
79 tcpu_dev = get_cpu_device(cpu);
80 if (!tcpu_dev)
81 continue;
82
83 tdomain = scpi_ops->device_domain_id(tcpu_dev);
84 if (tdomain == domain)
85 cpumask_set_cpu(cpu, cpumask);
86 }
87
88 return 0;
89}
90
91static int scpi_cpufreq_init(struct cpufreq_policy *policy)
92{
93 int ret;
94 unsigned int latency;
95 struct device *cpu_dev;
96 struct scpi_data *priv;
97 struct cpufreq_frequency_table *freq_table;
98
99 cpu_dev = get_cpu_device(policy->cpu);
100 if (!cpu_dev) {
101 pr_err("failed to get cpu%d device\n", policy->cpu);
102 return -ENODEV;
103 }
104
105 ret = scpi_ops->add_opps_to_device(cpu_dev);
106 if (ret) {
107 dev_warn(cpu_dev, "failed to add opps to the device\n");
108 return ret;
109 }
110
111 ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus);
112 if (ret) {
113 dev_warn(cpu_dev, "failed to get sharing cpumask\n");
114 return ret;
115 }
116
117 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
118 if (ret) {
119 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
120 __func__, ret);
121 return ret;
122 }
123
124 ret = dev_pm_opp_get_opp_count(cpu_dev);
125 if (ret <= 0) {
126 dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
127 ret = -EPROBE_DEFER;
128 goto out_free_opp;
129 }
130
131 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
132 if (!priv) {
133 ret = -ENOMEM;
134 goto out_free_opp;
135 }
136
137 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
138 if (ret) {
139 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
140 goto out_free_priv;
141 }
142
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 ret = PTR_ERR(priv->clk);
149 goto out_free_cpufreq_table;
150 }
151
152 policy->driver_data = priv;
153 policy->freq_table = freq_table;
154
155
156 policy->dvfs_possible_from_any_cpu = true;
157
158 latency = scpi_ops->get_transition_latency(cpu_dev);
159 if (!latency)
160 latency = CPUFREQ_ETERNAL;
161
162 policy->cpuinfo.transition_latency = latency;
163
164 policy->fast_switch_possible = false;
165
166 return 0;
167
168out_free_cpufreq_table:
169 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
170out_free_priv:
171 kfree(priv);
172out_free_opp:
173 dev_pm_opp_remove_all_dynamic(cpu_dev);
174
175 return ret;
176}
177
178static int scpi_cpufreq_exit(struct cpufreq_policy *policy)
179{
180 struct scpi_data *priv = policy->driver_data;
181
182 clk_put(priv->clk);
183 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
184 dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
185 kfree(priv);
186
187 return 0;
188}
189
190static struct cpufreq_driver scpi_cpufreq_driver = {
191 .name = "scpi-cpufreq",
192 .flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
193 CPUFREQ_NEED_INITIAL_FREQ_CHECK |
194 CPUFREQ_IS_COOLING_DEV,
195 .verify = cpufreq_generic_frequency_table_verify,
196 .attr = cpufreq_generic_attr,
197 .get = scpi_cpufreq_get_rate,
198 .init = scpi_cpufreq_init,
199 .exit = scpi_cpufreq_exit,
200 .target_index = scpi_cpufreq_set_target,
201 .register_em = cpufreq_register_em_with_opp,
202};
203
204static int scpi_cpufreq_probe(struct platform_device *pdev)
205{
206 int ret;
207
208 scpi_ops = get_scpi_ops();
209 if (!scpi_ops)
210 return -EIO;
211
212 ret = cpufreq_register_driver(&scpi_cpufreq_driver);
213 if (ret)
214 dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n",
215 __func__, ret);
216 return ret;
217}
218
219static int scpi_cpufreq_remove(struct platform_device *pdev)
220{
221 cpufreq_unregister_driver(&scpi_cpufreq_driver);
222 scpi_ops = NULL;
223 return 0;
224}
225
226static struct platform_driver scpi_cpufreq_platdrv = {
227 .driver = {
228 .name = "scpi-cpufreq",
229 },
230 .probe = scpi_cpufreq_probe,
231 .remove = scpi_cpufreq_remove,
232};
233module_platform_driver(scpi_cpufreq_platdrv);
234
235MODULE_ALIAS("platform:scpi-cpufreq");
236MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
237MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
238MODULE_LICENSE("GPL v2");
239
