Merge branches 'pm-cpufreq' and 'pm-devfreq'
[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 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 cpudata *cpu;
82         struct cpufreq_freqs freqs;
83         u32 desired_perf;
84         int ret = 0;
85
86         cpu = all_cpu_data[policy->cpu];
87
88         desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
89         /* Return if it is exactly the same perf */
90         if (desired_perf == cpu->perf_ctrls.desired_perf)
91                 return ret;
92
93         cpu->perf_ctrls.desired_perf = desired_perf;
94         freqs.old = policy->cur;
95         freqs.new = target_freq;
96
97         cpufreq_freq_transition_begin(policy, &freqs);
98         ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
99         cpufreq_freq_transition_end(policy, &freqs, ret != 0);
100
101         if (ret)
102                 pr_debug("Failed to set target on CPU:%d. ret:%d\n",
103                                 cpu->cpu, ret);
104
105         return ret;
106 }
107
108 static int cppc_verify_policy(struct cpufreq_policy *policy)
109 {
110         cpufreq_verify_within_cpu_limits(policy);
111         return 0;
112 }
113
114 static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
115 {
116         int cpu_num = policy->cpu;
117         struct cpudata *cpu = all_cpu_data[cpu_num];
118         int ret;
119
120         cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
121
122         ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
123         if (ret)
124                 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
125                                 cpu->perf_caps.lowest_perf, cpu_num, ret);
126 }
127
128 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
129 {
130         struct cpudata *cpu;
131         unsigned int cpu_num = policy->cpu;
132         int ret = 0;
133
134         cpu = all_cpu_data[policy->cpu];
135
136         cpu->cpu = cpu_num;
137         ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
138
139         if (ret) {
140                 pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
141                                 cpu_num, ret);
142                 return ret;
143         }
144
145         cppc_dmi_max_khz = cppc_get_dmi_max_khz();
146
147         policy->min = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz / cpu->perf_caps.highest_perf;
148         policy->max = cppc_dmi_max_khz;
149         policy->cpuinfo.min_freq = policy->min;
150         policy->cpuinfo.max_freq = policy->max;
151         policy->shared_type = cpu->shared_type;
152
153         if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
154                 cpumask_copy(policy->cpus, cpu->shared_cpu_map);
155         else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
156                 /* Support only SW_ANY for now. */
157                 pr_debug("Unsupported CPU co-ord type\n");
158                 return -EFAULT;
159         }
160
161         cpumask_set_cpu(policy->cpu, policy->cpus);
162         cpu->cur_policy = policy;
163
164         /* Set policy->cur to max now. The governors will adjust later. */
165         policy->cur = cppc_dmi_max_khz;
166         cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
167
168         ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
169         if (ret)
170                 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
171                                 cpu->perf_caps.highest_perf, cpu_num, ret);
172
173         return ret;
174 }
175
176 static struct cpufreq_driver cppc_cpufreq_driver = {
177         .flags = CPUFREQ_CONST_LOOPS,
178         .verify = cppc_verify_policy,
179         .target = cppc_cpufreq_set_target,
180         .init = cppc_cpufreq_cpu_init,
181         .stop_cpu = cppc_cpufreq_stop_cpu,
182         .name = "cppc_cpufreq",
183 };
184
185 static int __init cppc_cpufreq_init(void)
186 {
187         int i, ret = 0;
188         struct cpudata *cpu;
189
190         if (acpi_disabled)
191                 return -ENODEV;
192
193         all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL);
194         if (!all_cpu_data)
195                 return -ENOMEM;
196
197         for_each_possible_cpu(i) {
198                 all_cpu_data[i] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
199                 if (!all_cpu_data[i])
200                         goto out;
201
202                 cpu = all_cpu_data[i];
203                 if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
204                         goto out;
205         }
206
207         ret = acpi_get_psd_map(all_cpu_data);
208         if (ret) {
209                 pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
210                 goto out;
211         }
212
213         ret = cpufreq_register_driver(&cppc_cpufreq_driver);
214         if (ret)
215                 goto out;
216
217         return ret;
218
219 out:
220         for_each_possible_cpu(i)
221                 kfree(all_cpu_data[i]);
222
223         kfree(all_cpu_data);
224         return -ENODEV;
225 }
226
227 static void __exit cppc_cpufreq_exit(void)
228 {
229         struct cpudata *cpu;
230         int i;
231
232         cpufreq_unregister_driver(&cppc_cpufreq_driver);
233
234         for_each_possible_cpu(i) {
235                 cpu = all_cpu_data[i];
236                 free_cpumask_var(cpu->shared_cpu_map);
237                 kfree(cpu);
238         }
239
240         kfree(all_cpu_data);
241 }
242
243 module_exit(cppc_cpufreq_exit);
244 MODULE_AUTHOR("Ashwin Chaugule");
245 MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
246 MODULE_LICENSE("GPL");
247
248 late_initcall(cppc_cpufreq_init);