0f86d0253c60c896449d70852b77a64190e46991
[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 #include <linux/proc_fs.h>
34 #include <linux/seq_file.h>
35
36 #include <asm/uaccess.h>
37
38 #include <acpi/acpi_bus.h>
39 #include <acpi/processor.h>
40 #include <acpi/acpi_drivers.h>
41
42 #define ACPI_PROCESSOR_COMPONENT        0x01000000
43 #define ACPI_PROCESSOR_CLASS            "processor"
44 #define ACPI_PROCESSOR_DRIVER_NAME      "ACPI Processor Driver"
45 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
46 ACPI_MODULE_NAME("acpi_processor")
47
48 /* --------------------------------------------------------------------------
49                                  Limit Interface
50    -------------------------------------------------------------------------- */
51 static int acpi_processor_apply_limit(struct acpi_processor *pr)
52 {
53         int result = 0;
54         u16 px = 0;
55         u16 tx = 0;
56
57         ACPI_FUNCTION_TRACE("acpi_processor_apply_limit");
58
59         if (!pr)
60                 return_VALUE(-EINVAL);
61
62         if (!pr->flags.limit)
63                 return_VALUE(-ENODEV);
64
65         if (pr->flags.throttling) {
66                 if (pr->limit.user.tx > tx)
67                         tx = pr->limit.user.tx;
68                 if (pr->limit.thermal.tx > tx)
69                         tx = pr->limit.thermal.tx;
70
71                 result = acpi_processor_set_throttling(pr, tx);
72                 if (result)
73                         goto end;
74         }
75
76         pr->limit.state.px = px;
77         pr->limit.state.tx = tx;
78
79         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
80                           "Processor [%d] limit set to (P%d:T%d)\n", pr->id,
81                           pr->limit.state.px, pr->limit.state.tx));
82
83       end:
84         if (result)
85                 printk(KERN_ERR PREFIX "Unable to set limit\n");
86
87         return_VALUE(result);
88 }
89
90 #ifdef CONFIG_CPU_FREQ
91
92 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
93  * offers (in most cases) voltage scaling in addition to frequency scaling, and
94  * thus a cubic (instead of linear) reduction of energy. Also, we allow for
95  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
96  */
97
98 static unsigned int cpufreq_thermal_reduction_pctg[NR_CPUS];
99 static unsigned int acpi_thermal_cpufreq_is_init = 0;
100
101 static int cpu_has_cpufreq(unsigned int cpu)
102 {
103         struct cpufreq_policy policy;
104         if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
105                 return 0;
106         return 1;
107 }
108
109 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
110 {
111         if (!cpu_has_cpufreq(cpu))
112                 return -ENODEV;
113
114         if (cpufreq_thermal_reduction_pctg[cpu] < 60) {
115                 cpufreq_thermal_reduction_pctg[cpu] += 20;
116                 cpufreq_update_policy(cpu);
117                 return 0;
118         }
119
120         return -ERANGE;
121 }
122
123 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
124 {
125         if (!cpu_has_cpufreq(cpu))
126                 return -ENODEV;
127
128         if (cpufreq_thermal_reduction_pctg[cpu] > 20)
129                 cpufreq_thermal_reduction_pctg[cpu] -= 20;
130         else
131                 cpufreq_thermal_reduction_pctg[cpu] = 0;
132         cpufreq_update_policy(cpu);
133         /* We reached max freq again and can leave passive mode */
134         return !cpufreq_thermal_reduction_pctg[cpu];
135 }
136
137 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
138                                          unsigned long event, void *data)
139 {
140         struct cpufreq_policy *policy = data;
141         unsigned long max_freq = 0;
142
143         if (event != CPUFREQ_ADJUST)
144                 goto out;
145
146         max_freq =
147             (policy->cpuinfo.max_freq *
148              (100 - cpufreq_thermal_reduction_pctg[policy->cpu])) / 100;
149
150         cpufreq_verify_within_limits(policy, 0, max_freq);
151
152       out:
153         return 0;
154 }
155
156 static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
157         .notifier_call = acpi_thermal_cpufreq_notifier,
158 };
159
160 void acpi_thermal_cpufreq_init(void)
161 {
162         int i;
163
164         for (i = 0; i < NR_CPUS; i++)
165                 cpufreq_thermal_reduction_pctg[i] = 0;
166
167         i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
168                                       CPUFREQ_POLICY_NOTIFIER);
169         if (!i)
170                 acpi_thermal_cpufreq_is_init = 1;
171 }
172
173 void acpi_thermal_cpufreq_exit(void)
174 {
175         if (acpi_thermal_cpufreq_is_init)
176                 cpufreq_unregister_notifier
177                     (&acpi_thermal_cpufreq_notifier_block,
178                      CPUFREQ_POLICY_NOTIFIER);
179
180         acpi_thermal_cpufreq_is_init = 0;
181 }
182
183 #else                           /* ! CONFIG_CPU_FREQ */
184
185 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
186 {
187         return -ENODEV;
188 }
189 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
190 {
191         return -ENODEV;
192 }
193
194 #endif
195
196 int acpi_processor_set_thermal_limit(acpi_handle handle, int type)
197 {
198         int result = 0;
199         struct acpi_processor *pr = NULL;
200         struct acpi_device *device = NULL;
201         int tx = 0, max_tx_px = 0;
202
203         ACPI_FUNCTION_TRACE("acpi_processor_set_thermal_limit");
204
205         if ((type < ACPI_PROCESSOR_LIMIT_NONE)
206             || (type > ACPI_PROCESSOR_LIMIT_DECREMENT))
207                 return_VALUE(-EINVAL);
208
209         result = acpi_bus_get_device(handle, &device);
210         if (result)
211                 return_VALUE(result);
212
213         pr = (struct acpi_processor *)acpi_driver_data(device);
214         if (!pr)
215                 return_VALUE(-ENODEV);
216
217         /* Thermal limits are always relative to the current Px/Tx state. */
218         if (pr->flags.throttling)
219                 pr->limit.thermal.tx = pr->throttling.state;
220
221         /*
222          * Our default policy is to only use throttling at the lowest
223          * performance state.
224          */
225
226         tx = pr->limit.thermal.tx;
227
228         switch (type) {
229
230         case ACPI_PROCESSOR_LIMIT_NONE:
231                 do {
232                         result = acpi_thermal_cpufreq_decrease(pr->id);
233                 } while (!result);
234                 tx = 0;
235                 break;
236
237         case ACPI_PROCESSOR_LIMIT_INCREMENT:
238                 /* if going up: P-states first, T-states later */
239
240                 result = acpi_thermal_cpufreq_increase(pr->id);
241                 if (!result)
242                         goto end;
243                 else if (result == -ERANGE)
244                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
245                                           "At maximum performance state\n"));
246
247                 if (pr->flags.throttling) {
248                         if (tx == (pr->throttling.state_count - 1))
249                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
250                                                   "At maximum throttling state\n"));
251                         else
252                                 tx++;
253                 }
254                 break;
255
256         case ACPI_PROCESSOR_LIMIT_DECREMENT:
257                 /* if going down: T-states first, P-states later */
258
259                 if (pr->flags.throttling) {
260                         if (tx == 0) {
261                                 max_tx_px = 1;
262                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
263                                                   "At minimum throttling state\n"));
264                         } else {
265                                 tx--;
266                                 goto end;
267                         }
268                 }
269
270                 result = acpi_thermal_cpufreq_decrease(pr->id);
271                 if (result) {
272                         /*
273                          * We only could get -ERANGE, 1 or 0.
274                          * In the first two cases we reached max freq again.
275                          */
276                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
277                                           "At minimum performance state\n"));
278                         max_tx_px = 1;
279                 } else
280                         max_tx_px = 0;
281
282                 break;
283         }
284
285       end:
286         if (pr->flags.throttling) {
287                 pr->limit.thermal.px = 0;
288                 pr->limit.thermal.tx = tx;
289
290                 result = acpi_processor_apply_limit(pr);
291                 if (result)
292                         printk(KERN_ERR PREFIX "Unable to set thermal limit\n");
293
294                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n",
295                                   pr->limit.thermal.px, pr->limit.thermal.tx));
296         } else
297                 result = 0;
298         if (max_tx_px)
299                 return_VALUE(1);
300         else
301                 return_VALUE(result);
302 }
303
304 int acpi_processor_get_limit_info(struct acpi_processor *pr)
305 {
306         ACPI_FUNCTION_TRACE("acpi_processor_get_limit_info");
307
308         if (!pr)
309                 return_VALUE(-EINVAL);
310
311         if (pr->flags.throttling)
312                 pr->flags.limit = 1;
313
314         return_VALUE(0);
315 }
316
317 /* /proc interface */
318
319 static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset)
320 {
321         struct acpi_processor *pr = (struct acpi_processor *)seq->private;
322
323         ACPI_FUNCTION_TRACE("acpi_processor_limit_seq_show");
324
325         if (!pr)
326                 goto end;
327
328         if (!pr->flags.limit) {
329                 seq_puts(seq, "<not supported>\n");
330                 goto end;
331         }
332
333         seq_printf(seq, "active limit:            P%d:T%d\n"
334                    "user limit:              P%d:T%d\n"
335                    "thermal limit:           P%d:T%d\n",
336                    pr->limit.state.px, pr->limit.state.tx,
337                    pr->limit.user.px, pr->limit.user.tx,
338                    pr->limit.thermal.px, pr->limit.thermal.tx);
339
340       end:
341         return_VALUE(0);
342 }
343
344 static int acpi_processor_limit_open_fs(struct inode *inode, struct file *file)
345 {
346         return single_open(file, acpi_processor_limit_seq_show,
347                            PDE(inode)->data);
348 }
349
350 static ssize_t acpi_processor_write_limit(struct file * file,
351                                           const char __user * buffer,
352                                           size_t count, loff_t * data)
353 {
354         int result = 0;
355         struct seq_file *m = (struct seq_file *)file->private_data;
356         struct acpi_processor *pr = (struct acpi_processor *)m->private;
357         char limit_string[25] = { '\0' };
358         int px = 0;
359         int tx = 0;
360
361         ACPI_FUNCTION_TRACE("acpi_processor_write_limit");
362
363         if (!pr || (count > sizeof(limit_string) - 1)) {
364                 return_VALUE(-EINVAL);
365         }
366
367         if (copy_from_user(limit_string, buffer, count)) {
368                 return_VALUE(-EFAULT);
369         }
370
371         limit_string[count] = '\0';
372
373         if (sscanf(limit_string, "%d:%d", &px, &tx) != 2) {
374                 printk(KERN_ERR PREFIX "Invalid data format\n");
375                 return_VALUE(-EINVAL);
376         }
377
378         if (pr->flags.throttling) {
379                 if ((tx < 0) || (tx > (pr->throttling.state_count - 1))) {
380                         printk(KERN_ERR PREFIX "Invalid tx\n");
381                         return_VALUE(-EINVAL);
382                 }
383                 pr->limit.user.tx = tx;
384         }
385
386         result = acpi_processor_apply_limit(pr);
387
388         return_VALUE(count);
389 }
390
391 struct file_operations acpi_processor_limit_fops = {
392         .open = acpi_processor_limit_open_fs,
393         .read = seq_read,
394         .write = acpi_processor_write_limit,
395         .llseek = seq_lseek,
396         .release = single_release,
397 };