cpu: convert 'cpu' and 'machinecheck' sysdev_class to a regular subsystem
[linux-2.6.git] / drivers / acpi / processor_thermal.c
1 /*
2  * processor_thermal.c - Passive cooling submodule of the ACPI processor driver
3  *
4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6  *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
7  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
8  *                      - Added processor hotplug support
9  *
10  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
11  *
12  *  This program is free software; you can redistribute it and/or modify
13  *  it under the terms of the GNU General Public License as published by
14  *  the Free Software Foundation; either version 2 of the License, or (at
15  *  your option) any later version.
16  *
17  *  This program is distributed in the hope that it will be useful, but
18  *  WITHOUT ANY WARRANTY; without even the implied warranty of
19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20  *  General Public License for more details.
21  *
22  *  You should have received a copy of the GNU General Public License along
23  *  with this program; if not, write to the Free Software Foundation, Inc.,
24  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
25  *
26  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
27  */
28
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/init.h>
32 #include <linux/cpufreq.h>
33
34 #include <asm/uaccess.h>
35
36 #include <acpi/acpi_bus.h>
37 #include <acpi/processor.h>
38 #include <acpi/acpi_drivers.h>
39
40 #define PREFIX "ACPI: "
41
42 #define ACPI_PROCESSOR_CLASS            "processor"
43 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
44 ACPI_MODULE_NAME("processor_thermal");
45
46 #ifdef CONFIG_CPU_FREQ
47
48 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
49  * offers (in most cases) voltage scaling in addition to frequency scaling, and
50  * thus a cubic (instead of linear) reduction of energy. Also, we allow for
51  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
52  */
53
54 #define CPUFREQ_THERMAL_MIN_STEP 0
55 #define CPUFREQ_THERMAL_MAX_STEP 3
56
57 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
58 static unsigned int acpi_thermal_cpufreq_is_init = 0;
59
60 static int cpu_has_cpufreq(unsigned int cpu)
61 {
62         struct cpufreq_policy policy;
63         if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
64                 return 0;
65         return 1;
66 }
67
68 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
69                                          unsigned long event, void *data)
70 {
71         struct cpufreq_policy *policy = data;
72         unsigned long max_freq = 0;
73
74         if (event != CPUFREQ_ADJUST)
75                 goto out;
76
77         max_freq = (
78             policy->cpuinfo.max_freq *
79             (100 - per_cpu(cpufreq_thermal_reduction_pctg, policy->cpu) * 20)
80         ) / 100;
81
82         cpufreq_verify_within_limits(policy, 0, max_freq);
83
84       out:
85         return 0;
86 }
87
88 static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
89         .notifier_call = acpi_thermal_cpufreq_notifier,
90 };
91
92 static int cpufreq_get_max_state(unsigned int cpu)
93 {
94         if (!cpu_has_cpufreq(cpu))
95                 return 0;
96
97         return CPUFREQ_THERMAL_MAX_STEP;
98 }
99
100 static int cpufreq_get_cur_state(unsigned int cpu)
101 {
102         if (!cpu_has_cpufreq(cpu))
103                 return 0;
104
105         return per_cpu(cpufreq_thermal_reduction_pctg, cpu);
106 }
107
108 static int cpufreq_set_cur_state(unsigned int cpu, int state)
109 {
110         if (!cpu_has_cpufreq(cpu))
111                 return 0;
112
113         per_cpu(cpufreq_thermal_reduction_pctg, cpu) = state;
114         cpufreq_update_policy(cpu);
115         return 0;
116 }
117
118 void acpi_thermal_cpufreq_init(void)
119 {
120         int i;
121
122         for (i = 0; i < nr_cpu_ids; i++)
123                 if (cpu_present(i))
124                         per_cpu(cpufreq_thermal_reduction_pctg, i) = 0;
125
126         i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
127                                       CPUFREQ_POLICY_NOTIFIER);
128         if (!i)
129                 acpi_thermal_cpufreq_is_init = 1;
130 }
131
132 void acpi_thermal_cpufreq_exit(void)
133 {
134         if (acpi_thermal_cpufreq_is_init)
135                 cpufreq_unregister_notifier
136                     (&acpi_thermal_cpufreq_notifier_block,
137                      CPUFREQ_POLICY_NOTIFIER);
138
139         acpi_thermal_cpufreq_is_init = 0;
140 }
141
142 #else                           /* ! CONFIG_CPU_FREQ */
143 static int cpufreq_get_max_state(unsigned int cpu)
144 {
145         return 0;
146 }
147
148 static int cpufreq_get_cur_state(unsigned int cpu)
149 {
150         return 0;
151 }
152
153 static int cpufreq_set_cur_state(unsigned int cpu, int state)
154 {
155         return 0;
156 }
157
158 #endif
159
160 int acpi_processor_get_limit_info(struct acpi_processor *pr)
161 {
162
163         if (!pr)
164                 return -EINVAL;
165
166         if (pr->flags.throttling)
167                 pr->flags.limit = 1;
168
169         return 0;
170 }
171
172 /* thermal coolign device callbacks */
173 static int acpi_processor_max_state(struct acpi_processor *pr)
174 {
175         int max_state = 0;
176
177         /*
178          * There exists four states according to
179          * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3
180          */
181         max_state += cpufreq_get_max_state(pr->id);
182         if (pr->flags.throttling)
183                 max_state += (pr->throttling.state_count -1);
184
185         return max_state;
186 }
187 static int
188 processor_get_max_state(struct thermal_cooling_device *cdev,
189                         unsigned long *state)
190 {
191         struct acpi_device *device = cdev->devdata;
192         struct acpi_processor *pr = acpi_driver_data(device);
193
194         if (!device || !pr)
195                 return -EINVAL;
196
197         *state = acpi_processor_max_state(pr);
198         return 0;
199 }
200
201 static int
202 processor_get_cur_state(struct thermal_cooling_device *cdev,
203                         unsigned long *cur_state)
204 {
205         struct acpi_device *device = cdev->devdata;
206         struct acpi_processor *pr = acpi_driver_data(device);
207
208         if (!device || !pr)
209                 return -EINVAL;
210
211         *cur_state = cpufreq_get_cur_state(pr->id);
212         if (pr->flags.throttling)
213                 *cur_state += pr->throttling.state;
214         return 0;
215 }
216
217 static int
218 processor_set_cur_state(struct thermal_cooling_device *cdev,
219                         unsigned long state)
220 {
221         struct acpi_device *device = cdev->devdata;
222         struct acpi_processor *pr = acpi_driver_data(device);
223         int result = 0;
224         int max_pstate;
225
226         if (!device || !pr)
227                 return -EINVAL;
228
229         max_pstate = cpufreq_get_max_state(pr->id);
230
231         if (state > acpi_processor_max_state(pr))
232                 return -EINVAL;
233
234         if (state <= max_pstate) {
235                 if (pr->flags.throttling && pr->throttling.state)
236                         result = acpi_processor_set_throttling(pr, 0, false);
237                 cpufreq_set_cur_state(pr->id, state);
238         } else {
239                 cpufreq_set_cur_state(pr->id, max_pstate);
240                 result = acpi_processor_set_throttling(pr,
241                                 state - max_pstate, false);
242         }
243         return result;
244 }
245
246 const struct thermal_cooling_device_ops processor_cooling_ops = {
247         .get_max_state = processor_get_max_state,
248         .get_cur_state = processor_get_cur_state,
249         .set_cur_state = processor_set_cur_state,
250 };