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
cppc_cpufreq_set_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)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
cppc_verify_policy(struct cpufreq_policy * policy)60 static int cppc_verify_policy(struct cpufreq_policy *policy)
61 {
62 cpufreq_verify_within_cpu_limits(policy);
63 return 0;
64 }
65
cppc_cpufreq_stop_cpu(struct cpufreq_policy * policy)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
cppc_cpufreq_cpu_init(struct cpufreq_policy * policy)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
cppc_cpufreq_init(void)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);
192