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Ashwin Chaugule5477fb32015-10-02 10:04:01 -04001/*
2 * CPPC (Collaborative Processor Performance Control) driver for
3 * interfacing with the CPUfreq layer and governors. See
4 * cppc_acpi.c for CPPC specific methods.
5 *
6 * (C) Copyright 2014, 2015 Linaro Ltd.
7 * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; version 2
12 * of the License.
13 */
14
15#define pr_fmt(fmt) "CPPC Cpufreq:" fmt
16
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/delay.h>
20#include <linux/cpu.h>
21#include <linux/cpufreq.h>
22#include <linux/vmalloc.h>
23
24#include <acpi/cppc_acpi.h>
25
26/*
27 * These structs contain information parsed from per CPU
28 * ACPI _CPC structures.
29 * e.g. For each CPU the highest, lowest supported
30 * performance capabilities, desired performance level
31 * requested etc.
32 */
33static struct cpudata **all_cpu_data;
34
35static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
36 unsigned int target_freq,
37 unsigned int relation)
38{
39 struct cpudata *cpu;
40 struct cpufreq_freqs freqs;
41 int ret = 0;
42
43 cpu = all_cpu_data[policy->cpu];
44
45 cpu->perf_ctrls.desired_perf = target_freq;
46 freqs.old = policy->cur;
47 freqs.new = target_freq;
48
49 cpufreq_freq_transition_begin(policy, &freqs);
50 ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
51 cpufreq_freq_transition_end(policy, &freqs, ret != 0);
52
53 if (ret)
54 pr_debug("Failed to set target on CPU:%d. ret:%d\n",
55 cpu->cpu, ret);
56
57 return ret;
58}
59
60static int cppc_verify_policy(struct cpufreq_policy *policy)
61{
62 cpufreq_verify_within_cpu_limits(policy);
63 return 0;
64}
65
66static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
67{
68 int cpu_num = policy->cpu;
69 struct cpudata *cpu = all_cpu_data[cpu_num];
70 int ret;
71
72 cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
73
74 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
75 if (ret)
76 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
77 cpu->perf_caps.lowest_perf, cpu_num, ret);
78}
79
80static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
81{
82 struct cpudata *cpu;
83 unsigned int cpu_num = policy->cpu;
84 int ret = 0;
85
86 cpu = all_cpu_data[policy->cpu];
87
88 cpu->cpu = cpu_num;
89 ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
90
91 if (ret) {
92 pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
93 cpu_num, ret);
94 return ret;
95 }
96
97 policy->min = cpu->perf_caps.lowest_perf;
98 policy->max = cpu->perf_caps.highest_perf;
99 policy->cpuinfo.min_freq = policy->min;
100 policy->cpuinfo.max_freq = policy->max;
Ashwin Chaugule9dc17912015-11-19 10:40:07 -0500101 policy->shared_type = cpu->shared_type;
Ashwin Chaugule5477fb32015-10-02 10:04:01 -0400102
103 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
104 cpumask_copy(policy->cpus, cpu->shared_cpu_map);
Ashwin Chaugule9dc17912015-11-19 10:40:07 -0500105 else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
Ashwin Chaugule5477fb32015-10-02 10:04:01 -0400106 /* Support only SW_ANY for now. */
107 pr_debug("Unsupported CPU co-ord type\n");
108 return -EFAULT;
109 }
110
111 cpumask_set_cpu(policy->cpu, policy->cpus);
112 cpu->cur_policy = policy;
113
114 /* Set policy->cur to max now. The governors will adjust later. */
115 policy->cur = cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
116
117 ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
118 if (ret)
119 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
120 cpu->perf_caps.highest_perf, cpu_num, ret);
121
122 return ret;
123}
124
125static struct cpufreq_driver cppc_cpufreq_driver = {
126 .flags = CPUFREQ_CONST_LOOPS,
127 .verify = cppc_verify_policy,
128 .target = cppc_cpufreq_set_target,
129 .init = cppc_cpufreq_cpu_init,
130 .stop_cpu = cppc_cpufreq_stop_cpu,
131 .name = "cppc_cpufreq",
132};
133
134static int __init cppc_cpufreq_init(void)
135{
136 int i, ret = 0;
137 struct cpudata *cpu;
138
139 if (acpi_disabled)
140 return -ENODEV;
141
142 all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL);
143 if (!all_cpu_data)
144 return -ENOMEM;
145
146 for_each_possible_cpu(i) {
147 all_cpu_data[i] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
148 if (!all_cpu_data[i])
149 goto out;
150
151 cpu = all_cpu_data[i];
152 if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
153 goto out;
154 }
155
156 ret = acpi_get_psd_map(all_cpu_data);
157 if (ret) {
158 pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
159 goto out;
160 }
161
162 ret = cpufreq_register_driver(&cppc_cpufreq_driver);
163 if (ret)
164 goto out;
165
166 return ret;
167
168out:
169 for_each_possible_cpu(i)
Markus Elfringefb2d3b2015-11-05 21:10:29 +0100170 kfree(all_cpu_data[i]);
Ashwin Chaugule5477fb32015-10-02 10:04:01 -0400171
172 kfree(all_cpu_data);
173 return -ENODEV;
174}
175
Ashwin Chaugulea29a1e72016-04-14 20:45:53 -0400176static void __exit cppc_cpufreq_exit(void)
177{
178 struct cpudata *cpu;
179 int i;
180
181 cpufreq_unregister_driver(&cppc_cpufreq_driver);
182
183 for_each_possible_cpu(i) {
184 cpu = all_cpu_data[i];
185 free_cpumask_var(cpu->shared_cpu_map);
186 kfree(cpu);
187 }
188
189 kfree(all_cpu_data);
190}
191
192module_exit(cppc_cpufreq_exit);
193MODULE_AUTHOR("Ashwin Chaugule");
194MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
195MODULE_LICENSE("GPL");
196
Ashwin Chaugule5477fb32015-10-02 10:04:01 -0400197late_initcall(cppc_cpufreq_init);