S3C: Backported openmoko's touchscreen filters
[linux-2.6/mini2440.git] / drivers / acpi / processor_thermal.c
blob140c5c5b423c6361fabb3535e362eb9c18e71fb3
1 /*
2 * processor_thermal.c - Passive cooling submodule of the ACPI processor driver
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
10 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.
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.
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.
26 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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 #include <linux/sysdev.h>
37 #include <asm/uaccess.h>
39 #include <acpi/acpi_bus.h>
40 #include <acpi/processor.h>
41 #include <acpi/acpi_drivers.h>
43 #define PREFIX "ACPI: "
45 #define ACPI_PROCESSOR_CLASS "processor"
46 #define _COMPONENT ACPI_PROCESSOR_COMPONENT
47 ACPI_MODULE_NAME("processor_thermal");
49 /* --------------------------------------------------------------------------
50 Limit Interface
51 -------------------------------------------------------------------------- */
52 static int acpi_processor_apply_limit(struct acpi_processor *pr)
54 int result = 0;
55 u16 px = 0;
56 u16 tx = 0;
59 if (!pr)
60 return -EINVAL;
62 if (!pr->flags.limit)
63 return -ENODEV;
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;
71 result = acpi_processor_set_throttling(pr, tx, false);
72 if (result)
73 goto end;
76 pr->limit.state.px = px;
77 pr->limit.state.tx = tx;
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));
83 end:
84 if (result)
85 printk(KERN_ERR PREFIX "Unable to set limit\n");
87 return result;
90 #ifdef CONFIG_CPU_FREQ
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.
98 #define CPUFREQ_THERMAL_MIN_STEP 0
99 #define CPUFREQ_THERMAL_MAX_STEP 3
101 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
102 static unsigned int acpi_thermal_cpufreq_is_init = 0;
104 static int cpu_has_cpufreq(unsigned int cpu)
106 struct cpufreq_policy policy;
107 if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
108 return 0;
109 return 1;
112 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
114 if (!cpu_has_cpufreq(cpu))
115 return -ENODEV;
117 if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) <
118 CPUFREQ_THERMAL_MAX_STEP) {
119 per_cpu(cpufreq_thermal_reduction_pctg, cpu)++;
120 cpufreq_update_policy(cpu);
121 return 0;
124 return -ERANGE;
127 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
129 if (!cpu_has_cpufreq(cpu))
130 return -ENODEV;
132 if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) >
133 (CPUFREQ_THERMAL_MIN_STEP + 1))
134 per_cpu(cpufreq_thermal_reduction_pctg, cpu)--;
135 else
136 per_cpu(cpufreq_thermal_reduction_pctg, cpu) = 0;
137 cpufreq_update_policy(cpu);
138 /* We reached max freq again and can leave passive mode */
139 return !per_cpu(cpufreq_thermal_reduction_pctg, cpu);
142 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
143 unsigned long event, void *data)
145 struct cpufreq_policy *policy = data;
146 unsigned long max_freq = 0;
148 if (event != CPUFREQ_ADJUST)
149 goto out;
151 max_freq = (
152 policy->cpuinfo.max_freq *
153 (100 - per_cpu(cpufreq_thermal_reduction_pctg, policy->cpu) * 20)
154 ) / 100;
156 cpufreq_verify_within_limits(policy, 0, max_freq);
158 out:
159 return 0;
162 static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
163 .notifier_call = acpi_thermal_cpufreq_notifier,
166 static int cpufreq_get_max_state(unsigned int cpu)
168 if (!cpu_has_cpufreq(cpu))
169 return 0;
171 return CPUFREQ_THERMAL_MAX_STEP;
174 static int cpufreq_get_cur_state(unsigned int cpu)
176 if (!cpu_has_cpufreq(cpu))
177 return 0;
179 return per_cpu(cpufreq_thermal_reduction_pctg, cpu);
182 static int cpufreq_set_cur_state(unsigned int cpu, int state)
184 if (!cpu_has_cpufreq(cpu))
185 return 0;
187 per_cpu(cpufreq_thermal_reduction_pctg, cpu) = state;
188 cpufreq_update_policy(cpu);
189 return 0;
192 void acpi_thermal_cpufreq_init(void)
194 int i;
196 for (i = 0; i < nr_cpu_ids; i++)
197 if (cpu_present(i))
198 per_cpu(cpufreq_thermal_reduction_pctg, i) = 0;
200 i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
201 CPUFREQ_POLICY_NOTIFIER);
202 if (!i)
203 acpi_thermal_cpufreq_is_init = 1;
206 void acpi_thermal_cpufreq_exit(void)
208 if (acpi_thermal_cpufreq_is_init)
209 cpufreq_unregister_notifier
210 (&acpi_thermal_cpufreq_notifier_block,
211 CPUFREQ_POLICY_NOTIFIER);
213 acpi_thermal_cpufreq_is_init = 0;
216 #else /* ! CONFIG_CPU_FREQ */
217 static int cpufreq_get_max_state(unsigned int cpu)
219 return 0;
222 static int cpufreq_get_cur_state(unsigned int cpu)
224 return 0;
227 static int cpufreq_set_cur_state(unsigned int cpu, int state)
229 return 0;
232 static int acpi_thermal_cpufreq_increase(unsigned int cpu)
234 return -ENODEV;
236 static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
238 return -ENODEV;
241 #endif
243 int acpi_processor_set_thermal_limit(acpi_handle handle, int type)
245 int result = 0;
246 struct acpi_processor *pr = NULL;
247 struct acpi_device *device = NULL;
248 int tx = 0, max_tx_px = 0;
251 if ((type < ACPI_PROCESSOR_LIMIT_NONE)
252 || (type > ACPI_PROCESSOR_LIMIT_DECREMENT))
253 return -EINVAL;
255 result = acpi_bus_get_device(handle, &device);
256 if (result)
257 return result;
259 pr = acpi_driver_data(device);
260 if (!pr)
261 return -ENODEV;
263 /* Thermal limits are always relative to the current Px/Tx state. */
264 if (pr->flags.throttling)
265 pr->limit.thermal.tx = pr->throttling.state;
268 * Our default policy is to only use throttling at the lowest
269 * performance state.
272 tx = pr->limit.thermal.tx;
274 switch (type) {
276 case ACPI_PROCESSOR_LIMIT_NONE:
277 do {
278 result = acpi_thermal_cpufreq_decrease(pr->id);
279 } while (!result);
280 tx = 0;
281 break;
283 case ACPI_PROCESSOR_LIMIT_INCREMENT:
284 /* if going up: P-states first, T-states later */
286 result = acpi_thermal_cpufreq_increase(pr->id);
287 if (!result)
288 goto end;
289 else if (result == -ERANGE)
290 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
291 "At maximum performance state\n"));
293 if (pr->flags.throttling) {
294 if (tx == (pr->throttling.state_count - 1))
295 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
296 "At maximum throttling state\n"));
297 else
298 tx++;
300 break;
302 case ACPI_PROCESSOR_LIMIT_DECREMENT:
303 /* if going down: T-states first, P-states later */
305 if (pr->flags.throttling) {
306 if (tx == 0) {
307 max_tx_px = 1;
308 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
309 "At minimum throttling state\n"));
310 } else {
311 tx--;
312 goto end;
316 result = acpi_thermal_cpufreq_decrease(pr->id);
317 if (result) {
319 * We only could get -ERANGE, 1 or 0.
320 * In the first two cases we reached max freq again.
322 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
323 "At minimum performance state\n"));
324 max_tx_px = 1;
325 } else
326 max_tx_px = 0;
328 break;
331 end:
332 if (pr->flags.throttling) {
333 pr->limit.thermal.px = 0;
334 pr->limit.thermal.tx = tx;
336 result = acpi_processor_apply_limit(pr);
337 if (result)
338 printk(KERN_ERR PREFIX "Unable to set thermal limit\n");
340 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n",
341 pr->limit.thermal.px, pr->limit.thermal.tx));
342 } else
343 result = 0;
344 if (max_tx_px)
345 return 1;
346 else
347 return result;
350 int acpi_processor_get_limit_info(struct acpi_processor *pr)
353 if (!pr)
354 return -EINVAL;
356 if (pr->flags.throttling)
357 pr->flags.limit = 1;
359 return 0;
362 /* thermal coolign device callbacks */
363 static int acpi_processor_max_state(struct acpi_processor *pr)
365 int max_state = 0;
368 * There exists four states according to
369 * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3
371 max_state += cpufreq_get_max_state(pr->id);
372 if (pr->flags.throttling)
373 max_state += (pr->throttling.state_count -1);
375 return max_state;
377 static int
378 processor_get_max_state(struct thermal_cooling_device *cdev,
379 unsigned long *state)
381 struct acpi_device *device = cdev->devdata;
382 struct acpi_processor *pr = acpi_driver_data(device);
384 if (!device || !pr)
385 return -EINVAL;
387 *state = acpi_processor_max_state(pr);
388 return 0;
391 static int
392 processor_get_cur_state(struct thermal_cooling_device *cdev,
393 unsigned long *cur_state)
395 struct acpi_device *device = cdev->devdata;
396 struct acpi_processor *pr = acpi_driver_data(device);
398 if (!device || !pr)
399 return -EINVAL;
401 *cur_state = cpufreq_get_cur_state(pr->id);
402 if (pr->flags.throttling)
403 *cur_state += pr->throttling.state;
404 return 0;
407 static int
408 processor_set_cur_state(struct thermal_cooling_device *cdev,
409 unsigned long state)
411 struct acpi_device *device = cdev->devdata;
412 struct acpi_processor *pr = acpi_driver_data(device);
413 int result = 0;
414 int max_pstate;
416 if (!device || !pr)
417 return -EINVAL;
419 max_pstate = cpufreq_get_max_state(pr->id);
421 if (state > acpi_processor_max_state(pr))
422 return -EINVAL;
424 if (state <= max_pstate) {
425 if (pr->flags.throttling && pr->throttling.state)
426 result = acpi_processor_set_throttling(pr, 0, false);
427 cpufreq_set_cur_state(pr->id, state);
428 } else {
429 cpufreq_set_cur_state(pr->id, max_pstate);
430 result = acpi_processor_set_throttling(pr,
431 state - max_pstate, false);
433 return result;
436 struct thermal_cooling_device_ops processor_cooling_ops = {
437 .get_max_state = processor_get_max_state,
438 .get_cur_state = processor_get_cur_state,
439 .set_cur_state = processor_set_cur_state,
442 /* /proc interface */
443 #ifdef CONFIG_ACPI_PROCFS
444 static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset)
446 struct acpi_processor *pr = (struct acpi_processor *)seq->private;
449 if (!pr)
450 goto end;
452 if (!pr->flags.limit) {
453 seq_puts(seq, "<not supported>\n");
454 goto end;
457 seq_printf(seq, "active limit: P%d:T%d\n"
458 "user limit: P%d:T%d\n"
459 "thermal limit: P%d:T%d\n",
460 pr->limit.state.px, pr->limit.state.tx,
461 pr->limit.user.px, pr->limit.user.tx,
462 pr->limit.thermal.px, pr->limit.thermal.tx);
464 end:
465 return 0;
468 static int acpi_processor_limit_open_fs(struct inode *inode, struct file *file)
470 return single_open(file, acpi_processor_limit_seq_show,
471 PDE(inode)->data);
474 static ssize_t acpi_processor_write_limit(struct file * file,
475 const char __user * buffer,
476 size_t count, loff_t * data)
478 int result = 0;
479 struct seq_file *m = file->private_data;
480 struct acpi_processor *pr = m->private;
481 char limit_string[25] = { '\0' };
482 int px = 0;
483 int tx = 0;
486 if (!pr || (count > sizeof(limit_string) - 1)) {
487 return -EINVAL;
490 if (copy_from_user(limit_string, buffer, count)) {
491 return -EFAULT;
494 limit_string[count] = '\0';
496 if (sscanf(limit_string, "%d:%d", &px, &tx) != 2) {
497 printk(KERN_ERR PREFIX "Invalid data format\n");
498 return -EINVAL;
501 if (pr->flags.throttling) {
502 if ((tx < 0) || (tx > (pr->throttling.state_count - 1))) {
503 printk(KERN_ERR PREFIX "Invalid tx\n");
504 return -EINVAL;
506 pr->limit.user.tx = tx;
509 result = acpi_processor_apply_limit(pr);
511 return count;
514 const struct file_operations acpi_processor_limit_fops = {
515 .owner = THIS_MODULE,
516 .open = acpi_processor_limit_open_fs,
517 .read = seq_read,
518 .write = acpi_processor_write_limit,
519 .llseek = seq_lseek,
520 .release = single_release,
522 #endif