GNU Linux-libre 4.4.289-gnu1
[releases.git] / drivers / cpufreq / cppc_cpufreq.c
1 /*
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  */
33 static struct cpudata **all_cpu_data;
34
35 static 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
60 static int cppc_verify_policy(struct cpufreq_policy *policy)
61 {
62         cpufreq_verify_within_cpu_limits(policy);
63         return 0;
64 }
65
66 static 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
80 static 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;
101         policy->shared_type = cpu->shared_type;
102
103         if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
104                 int i;
105
106                 cpumask_copy(policy->cpus, cpu->shared_cpu_map);
107
108                 for_each_cpu(i, policy->cpus) {
109                         if (unlikely(i == policy->cpu))
110                                 continue;
111
112                         memcpy(&all_cpu_data[i]->perf_caps, &cpu->perf_caps,
113                                sizeof(cpu->perf_caps));
114                 }
115         } else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
116                 /* Support only SW_ANY for now. */
117                 pr_debug("Unsupported CPU co-ord type\n");
118                 return -EFAULT;
119         }
120
121         cpumask_set_cpu(policy->cpu, policy->cpus);
122         cpu->cur_policy = policy;
123
124         /* Set policy->cur to max now. The governors will adjust later. */
125         policy->cur = cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
126
127         ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
128         if (ret)
129                 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
130                                 cpu->perf_caps.highest_perf, cpu_num, ret);
131
132         return ret;
133 }
134
135 static struct cpufreq_driver cppc_cpufreq_driver = {
136         .flags = CPUFREQ_CONST_LOOPS,
137         .verify = cppc_verify_policy,
138         .target = cppc_cpufreq_set_target,
139         .init = cppc_cpufreq_cpu_init,
140         .stop_cpu = cppc_cpufreq_stop_cpu,
141         .name = "cppc_cpufreq",
142 };
143
144 static int __init cppc_cpufreq_init(void)
145 {
146         int i, ret = 0;
147         struct cpudata *cpu;
148
149         if (acpi_disabled)
150                 return -ENODEV;
151
152         all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL);
153         if (!all_cpu_data)
154                 return -ENOMEM;
155
156         for_each_possible_cpu(i) {
157                 all_cpu_data[i] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
158                 if (!all_cpu_data[i])
159                         goto out;
160
161                 cpu = all_cpu_data[i];
162                 if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
163                         goto out;
164         }
165
166         ret = acpi_get_psd_map(all_cpu_data);
167         if (ret) {
168                 pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
169                 goto out;
170         }
171
172         ret = cpufreq_register_driver(&cppc_cpufreq_driver);
173         if (ret)
174                 goto out;
175
176         return ret;
177
178 out:
179         for_each_possible_cpu(i) {
180                 cpu = all_cpu_data[i];
181                 if (!cpu)
182                         break;
183                 free_cpumask_var(cpu->shared_cpu_map);
184                 kfree(cpu);
185         }
186
187         kfree(all_cpu_data);
188         return -ENODEV;
189 }
190
191 late_initcall(cppc_cpufreq_init);