Merge branch 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
[muen/linux.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/dmi.h>
23 #include <linux/vmalloc.h>
24
25 #include <asm/unaligned.h>
26
27 #include <acpi/cppc_acpi.h>
28
29 /* Minimum struct length needed for the DMI processor entry we want */
30 #define DMI_ENTRY_PROCESSOR_MIN_LENGTH  48
31
32 /* Offest in the DMI processor structure for the max frequency */
33 #define DMI_PROCESSOR_MAX_SPEED  0x14
34
35 /*
36  * These structs contain information parsed from per CPU
37  * ACPI _CPC structures.
38  * e.g. For each CPU the highest, lowest supported
39  * performance capabilities, desired performance level
40  * requested etc.
41  */
42 static struct cppc_cpudata **all_cpu_data;
43
44 /* Capture the max KHz from DMI */
45 static u64 cppc_dmi_max_khz;
46
47 /* Callback function used to retrieve the max frequency from DMI */
48 static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
49 {
50         const u8 *dmi_data = (const u8 *)dm;
51         u16 *mhz = (u16 *)private;
52
53         if (dm->type == DMI_ENTRY_PROCESSOR &&
54             dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
55                 u16 val = (u16)get_unaligned((const u16 *)
56                                 (dmi_data + DMI_PROCESSOR_MAX_SPEED));
57                 *mhz = val > *mhz ? val : *mhz;
58         }
59 }
60
61 /* Look up the max frequency in DMI */
62 static u64 cppc_get_dmi_max_khz(void)
63 {
64         u16 mhz = 0;
65
66         dmi_walk(cppc_find_dmi_mhz, &mhz);
67
68         /*
69          * Real stupid fallback value, just in case there is no
70          * actual value set.
71          */
72         mhz = mhz ? mhz : 1;
73
74         return (1000 * mhz);
75 }
76
77 static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
78                 unsigned int target_freq,
79                 unsigned int relation)
80 {
81         struct cppc_cpudata *cpu;
82         struct cpufreq_freqs freqs;
83         int ret = 0;
84
85         cpu = all_cpu_data[policy->cpu];
86
87         cpu->perf_ctrls.desired_perf = (u64)target_freq * policy->max / cppc_dmi_max_khz;
88         freqs.old = policy->cur;
89         freqs.new = target_freq;
90
91         cpufreq_freq_transition_begin(policy, &freqs);
92         ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
93         cpufreq_freq_transition_end(policy, &freqs, ret != 0);
94
95         if (ret)
96                 pr_debug("Failed to set target on CPU:%d. ret:%d\n",
97                                 cpu->cpu, ret);
98
99         return ret;
100 }
101
102 static int cppc_verify_policy(struct cpufreq_policy *policy)
103 {
104         cpufreq_verify_within_cpu_limits(policy);
105         return 0;
106 }
107
108 static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
109 {
110         int cpu_num = policy->cpu;
111         struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
112         int ret;
113
114         cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
115
116         ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
117         if (ret)
118                 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
119                                 cpu->perf_caps.lowest_perf, cpu_num, ret);
120 }
121
122 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
123 {
124         struct cppc_cpudata *cpu;
125         unsigned int cpu_num = policy->cpu;
126         int ret = 0;
127
128         cpu = all_cpu_data[policy->cpu];
129
130         cpu->cpu = cpu_num;
131         ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
132
133         if (ret) {
134                 pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
135                                 cpu_num, ret);
136                 return ret;
137         }
138
139         cppc_dmi_max_khz = cppc_get_dmi_max_khz();
140
141         policy->min = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz / cpu->perf_caps.highest_perf;
142         policy->max = cppc_dmi_max_khz;
143         policy->cpuinfo.min_freq = policy->min;
144         policy->cpuinfo.max_freq = policy->max;
145         policy->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num);
146         policy->shared_type = cpu->shared_type;
147
148         if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
149                 cpumask_copy(policy->cpus, cpu->shared_cpu_map);
150         else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
151                 /* Support only SW_ANY for now. */
152                 pr_debug("Unsupported CPU co-ord type\n");
153                 return -EFAULT;
154         }
155
156         cpumask_set_cpu(policy->cpu, policy->cpus);
157         cpu->cur_policy = policy;
158
159         /* Set policy->cur to max now. The governors will adjust later. */
160         policy->cur = cppc_dmi_max_khz;
161         cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
162
163         ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
164         if (ret)
165                 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
166                                 cpu->perf_caps.highest_perf, cpu_num, ret);
167
168         return ret;
169 }
170
171 static struct cpufreq_driver cppc_cpufreq_driver = {
172         .flags = CPUFREQ_CONST_LOOPS,
173         .verify = cppc_verify_policy,
174         .target = cppc_cpufreq_set_target,
175         .init = cppc_cpufreq_cpu_init,
176         .stop_cpu = cppc_cpufreq_stop_cpu,
177         .name = "cppc_cpufreq",
178 };
179
180 static int __init cppc_cpufreq_init(void)
181 {
182         int i, ret = 0;
183         struct cppc_cpudata *cpu;
184
185         if (acpi_disabled)
186                 return -ENODEV;
187
188         all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL);
189         if (!all_cpu_data)
190                 return -ENOMEM;
191
192         for_each_possible_cpu(i) {
193                 all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
194                 if (!all_cpu_data[i])
195                         goto out;
196
197                 cpu = all_cpu_data[i];
198                 if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
199                         goto out;
200         }
201
202         ret = acpi_get_psd_map(all_cpu_data);
203         if (ret) {
204                 pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
205                 goto out;
206         }
207
208         ret = cpufreq_register_driver(&cppc_cpufreq_driver);
209         if (ret)
210                 goto out;
211
212         return ret;
213
214 out:
215         for_each_possible_cpu(i)
216                 kfree(all_cpu_data[i]);
217
218         kfree(all_cpu_data);
219         return -ENODEV;
220 }
221
222 static void __exit cppc_cpufreq_exit(void)
223 {
224         struct cppc_cpudata *cpu;
225         int i;
226
227         cpufreq_unregister_driver(&cppc_cpufreq_driver);
228
229         for_each_possible_cpu(i) {
230                 cpu = all_cpu_data[i];
231                 free_cpumask_var(cpu->shared_cpu_map);
232                 kfree(cpu);
233         }
234
235         kfree(all_cpu_data);
236 }
237
238 module_exit(cppc_cpufreq_exit);
239 MODULE_AUTHOR("Ashwin Chaugule");
240 MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
241 MODULE_LICENSE("GPL");
242
243 late_initcall(cppc_cpufreq_init);