ia64/linux-2.6.18-xen.hg

view arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c @ 531:3c564f80f2ef

Notify ACPI processor events to external logic, including C/P/T and hotplug, etc.

Signed-off-by: Tian Kevin <kevin.tian@intel.com>
Signed-off-by: Wei Gang <gang.wei@intel.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu May 01 10:52:31 2008 +0100 (2008-05-01)
parents 3e8752eb6d9c
children e39cf97647af
line source
1 /*
2 * acpi-cpufreq.c - ACPI Processor P-States Driver ($Revision: 1.3 $)
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) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
7 *
8 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or (at
13 * your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License along
21 * with this program; if not, write to the Free Software Foundation, Inc.,
22 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
23 *
24 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
25 */
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/init.h>
30 #include <linux/cpufreq.h>
31 #include <linux/proc_fs.h>
32 #include <linux/seq_file.h>
33 #include <linux/compiler.h>
34 #include <linux/sched.h> /* current */
35 #include <asm/io.h>
36 #include <asm/delay.h>
37 #include <asm/uaccess.h>
39 #include <linux/acpi.h>
40 #include <acpi/processor.h>
42 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
44 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
45 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
46 MODULE_LICENSE("GPL");
49 struct cpufreq_acpi_io {
50 struct acpi_processor_performance *acpi_data;
51 struct cpufreq_frequency_table *freq_table;
52 unsigned int resume;
53 };
55 static struct cpufreq_acpi_io *acpi_io_data[NR_CPUS];
56 static struct acpi_processor_performance *acpi_perf_data[NR_CPUS];
58 static struct cpufreq_driver acpi_cpufreq_driver;
60 static unsigned int acpi_pstate_strict;
62 static int
63 acpi_processor_write_port(
64 u16 port,
65 u8 bit_width,
66 u32 value)
67 {
68 if (bit_width <= 8) {
69 outb(value, port);
70 } else if (bit_width <= 16) {
71 outw(value, port);
72 } else if (bit_width <= 32) {
73 outl(value, port);
74 } else {
75 return -ENODEV;
76 }
77 return 0;
78 }
80 static int
81 acpi_processor_read_port(
82 u16 port,
83 u8 bit_width,
84 u32 *ret)
85 {
86 *ret = 0;
87 if (bit_width <= 8) {
88 *ret = inb(port);
89 } else if (bit_width <= 16) {
90 *ret = inw(port);
91 } else if (bit_width <= 32) {
92 *ret = inl(port);
93 } else {
94 return -ENODEV;
95 }
96 return 0;
97 }
99 static int
100 acpi_processor_set_performance (
101 struct cpufreq_acpi_io *data,
102 unsigned int cpu,
103 int state)
104 {
105 u16 port = 0;
106 u8 bit_width = 0;
107 int i = 0;
108 int ret = 0;
109 u32 value = 0;
110 int retval;
111 struct acpi_processor_performance *perf;
113 dprintk("acpi_processor_set_performance\n");
115 retval = 0;
116 perf = data->acpi_data;
117 if (state == perf->state) {
118 if (unlikely(data->resume)) {
119 dprintk("Called after resume, resetting to P%d\n", state);
120 data->resume = 0;
121 } else {
122 dprintk("Already at target state (P%d)\n", state);
123 return (retval);
124 }
125 }
127 dprintk("Transitioning from P%d to P%d\n", perf->state, state);
129 /*
130 * First we write the target state's 'control' value to the
131 * control_register.
132 */
134 port = perf->control_register.address;
135 bit_width = perf->control_register.bit_width;
136 value = (u32) perf->states[state].control;
138 dprintk("Writing 0x%08x to port 0x%04x\n", value, port);
140 ret = acpi_processor_write_port(port, bit_width, value);
141 if (ret) {
142 dprintk("Invalid port width 0x%04x\n", bit_width);
143 return (ret);
144 }
146 /*
147 * Assume the write went through when acpi_pstate_strict is not used.
148 * As read status_register is an expensive operation and there
149 * are no specific error cases where an IO port write will fail.
150 */
151 if (acpi_pstate_strict) {
152 /* Then we read the 'status_register' and compare the value
153 * with the target state's 'status' to make sure the
154 * transition was successful.
155 * Note that we'll poll for up to 1ms (100 cycles of 10us)
156 * before giving up.
157 */
159 port = perf->status_register.address;
160 bit_width = perf->status_register.bit_width;
162 dprintk("Looking for 0x%08x from port 0x%04x\n",
163 (u32) perf->states[state].status, port);
165 for (i = 0; i < 100; i++) {
166 ret = acpi_processor_read_port(port, bit_width, &value);
167 if (ret) {
168 dprintk("Invalid port width 0x%04x\n", bit_width);
169 return (ret);
170 }
171 if (value == (u32) perf->states[state].status)
172 break;
173 udelay(10);
174 }
175 } else {
176 value = (u32) perf->states[state].status;
177 }
179 if (unlikely(value != (u32) perf->states[state].status)) {
180 printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
181 retval = -ENODEV;
182 return (retval);
183 }
185 dprintk("Transition successful after %d microseconds\n", i * 10);
187 perf->state = state;
188 return (retval);
189 }
192 static int
193 acpi_cpufreq_target (
194 struct cpufreq_policy *policy,
195 unsigned int target_freq,
196 unsigned int relation)
197 {
198 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
199 struct acpi_processor_performance *perf;
200 struct cpufreq_freqs freqs;
201 cpumask_t online_policy_cpus;
202 cpumask_t saved_mask;
203 cpumask_t set_mask;
204 cpumask_t covered_cpus;
205 unsigned int cur_state = 0;
206 unsigned int next_state = 0;
207 unsigned int result = 0;
208 unsigned int j;
209 unsigned int tmp;
211 dprintk("acpi_cpufreq_setpolicy\n");
213 result = cpufreq_frequency_table_target(policy,
214 data->freq_table,
215 target_freq,
216 relation,
217 &next_state);
218 if (unlikely(result))
219 return (result);
221 perf = data->acpi_data;
222 cur_state = perf->state;
223 freqs.old = data->freq_table[cur_state].frequency;
224 freqs.new = data->freq_table[next_state].frequency;
226 #ifdef CONFIG_HOTPLUG_CPU
227 /* cpufreq holds the hotplug lock, so we are safe from here on */
228 cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
229 #else
230 online_policy_cpus = policy->cpus;
231 #endif
233 for_each_cpu_mask(j, online_policy_cpus) {
234 freqs.cpu = j;
235 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
236 }
238 /*
239 * We need to call driver->target() on all or any CPU in
240 * policy->cpus, depending on policy->shared_type.
241 */
242 saved_mask = current->cpus_allowed;
243 cpus_clear(covered_cpus);
244 for_each_cpu_mask(j, online_policy_cpus) {
245 /*
246 * Support for SMP systems.
247 * Make sure we are running on CPU that wants to change freq
248 */
249 cpus_clear(set_mask);
250 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
251 cpus_or(set_mask, set_mask, online_policy_cpus);
252 else
253 cpu_set(j, set_mask);
255 set_cpus_allowed(current, set_mask);
256 if (unlikely(!cpu_isset(smp_processor_id(), set_mask))) {
257 dprintk("couldn't limit to CPUs in this domain\n");
258 result = -EAGAIN;
259 break;
260 }
262 result = acpi_processor_set_performance (data, j, next_state);
263 if (result) {
264 result = -EAGAIN;
265 break;
266 }
268 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
269 break;
271 cpu_set(j, covered_cpus);
272 }
274 for_each_cpu_mask(j, online_policy_cpus) {
275 freqs.cpu = j;
276 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
277 }
279 if (unlikely(result)) {
280 /*
281 * We have failed halfway through the frequency change.
282 * We have sent callbacks to online_policy_cpus and
283 * acpi_processor_set_performance() has been called on
284 * coverd_cpus. Best effort undo..
285 */
287 if (!cpus_empty(covered_cpus)) {
288 for_each_cpu_mask(j, covered_cpus) {
289 policy->cpu = j;
290 acpi_processor_set_performance (data,
291 j,
292 cur_state);
293 }
294 }
296 tmp = freqs.new;
297 freqs.new = freqs.old;
298 freqs.old = tmp;
299 for_each_cpu_mask(j, online_policy_cpus) {
300 freqs.cpu = j;
301 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
302 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
303 }
304 }
306 set_cpus_allowed(current, saved_mask);
307 return (result);
308 }
311 static int
312 acpi_cpufreq_verify (
313 struct cpufreq_policy *policy)
314 {
315 unsigned int result = 0;
316 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
318 dprintk("acpi_cpufreq_verify\n");
320 result = cpufreq_frequency_table_verify(policy,
321 data->freq_table);
323 return (result);
324 }
327 static unsigned long
328 acpi_cpufreq_guess_freq (
329 struct cpufreq_acpi_io *data,
330 unsigned int cpu)
331 {
332 struct acpi_processor_performance *perf = data->acpi_data;
334 if (cpu_khz) {
335 /* search the closest match to cpu_khz */
336 unsigned int i;
337 unsigned long freq;
338 unsigned long freqn = perf->states[0].core_frequency * 1000;
340 for (i = 0; i < (perf->state_count - 1); i++) {
341 freq = freqn;
342 freqn = perf->states[i+1].core_frequency * 1000;
343 if ((2 * cpu_khz) > (freqn + freq)) {
344 perf->state = i;
345 return (freq);
346 }
347 }
348 perf->state = perf->state_count - 1;
349 return (freqn);
350 } else {
351 /* assume CPU is at P0... */
352 perf->state = 0;
353 return perf->states[0].core_frequency * 1000;
354 }
355 }
358 /*
359 * acpi_cpufreq_early_init - initialize ACPI P-States library
360 *
361 * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
362 * in order to determine correct frequency and voltage pairings. We can
363 * do _PDC and _PSD and find out the processor dependency for the
364 * actual init that will happen later...
365 */
366 static int acpi_cpufreq_early_init_acpi(void)
367 {
368 struct acpi_processor_performance *data;
369 unsigned int i, j;
371 dprintk("acpi_cpufreq_early_init\n");
373 for_each_possible_cpu(i) {
374 data = kzalloc(sizeof(struct acpi_processor_performance),
375 GFP_KERNEL);
376 if (!data) {
377 for_each_possible_cpu(j) {
378 kfree(acpi_perf_data[j]);
379 acpi_perf_data[j] = NULL;
380 }
381 return (-ENOMEM);
382 }
383 acpi_perf_data[i] = data;
384 }
386 /* Do initialization in ACPI core */
387 return acpi_processor_preregister_performance(acpi_perf_data);
388 }
390 static int
391 acpi_cpufreq_cpu_init (
392 struct cpufreq_policy *policy)
393 {
394 unsigned int i;
395 unsigned int cpu = policy->cpu;
396 struct cpufreq_acpi_io *data;
397 unsigned int result = 0;
398 struct cpuinfo_x86 *c = &cpu_data[policy->cpu];
399 struct acpi_processor_performance *perf;
401 dprintk("acpi_cpufreq_cpu_init\n");
403 if (!acpi_perf_data[cpu])
404 return (-ENODEV);
406 data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
407 if (!data)
408 return (-ENOMEM);
410 data->acpi_data = acpi_perf_data[cpu];
411 acpi_io_data[cpu] = data;
413 result = acpi_processor_register_performance(data->acpi_data, cpu);
415 if (result)
416 goto err_free;
418 perf = data->acpi_data;
419 policy->shared_type = perf->shared_type;
420 /*
421 * Will let policy->cpus know about dependency only when software
422 * coordination is required.
423 */
424 if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
425 policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
426 policy->cpus = perf->shared_cpu_map;
428 if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
429 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
430 }
432 /* capability check */
433 if (perf->state_count <= 1) {
434 dprintk("No P-States\n");
435 result = -ENODEV;
436 goto err_unreg;
437 }
439 if ((perf->control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
440 (perf->status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
441 dprintk("Unsupported address space [%d, %d]\n",
442 (u32) (perf->control_register.space_id),
443 (u32) (perf->status_register.space_id));
444 result = -ENODEV;
445 goto err_unreg;
446 }
448 /* alloc freq_table */
449 data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (perf->state_count + 1), GFP_KERNEL);
450 if (!data->freq_table) {
451 result = -ENOMEM;
452 goto err_unreg;
453 }
455 /* detect transition latency */
456 policy->cpuinfo.transition_latency = 0;
457 for (i=0; i<perf->state_count; i++) {
458 if ((perf->states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
459 policy->cpuinfo.transition_latency = perf->states[i].transition_latency * 1000;
460 }
461 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
463 /* The current speed is unknown and not detectable by ACPI... */
464 policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
466 /* table init */
467 for (i=0; i<=perf->state_count; i++)
468 {
469 data->freq_table[i].index = i;
470 if (i<perf->state_count)
471 data->freq_table[i].frequency = perf->states[i].core_frequency * 1000;
472 else
473 data->freq_table[i].frequency = CPUFREQ_TABLE_END;
474 }
476 result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
477 if (result) {
478 goto err_freqfree;
479 }
481 /* notify BIOS that we exist */
482 acpi_processor_notify_smm(THIS_MODULE);
484 printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management activated.\n",
485 cpu);
486 for (i = 0; i < perf->state_count; i++)
487 dprintk(" %cP%d: %d MHz, %d mW, %d uS\n",
488 (i == perf->state?'*':' '), i,
489 (u32) perf->states[i].core_frequency,
490 (u32) perf->states[i].power,
491 (u32) perf->states[i].transition_latency);
493 cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
495 /*
496 * the first call to ->target() should result in us actually
497 * writing something to the appropriate registers.
498 */
499 data->resume = 1;
501 return (result);
503 err_freqfree:
504 kfree(data->freq_table);
505 err_unreg:
506 acpi_processor_unregister_performance(perf, cpu);
507 err_free:
508 kfree(data);
509 acpi_io_data[cpu] = NULL;
511 return (result);
512 }
515 static int
516 acpi_cpufreq_cpu_exit (
517 struct cpufreq_policy *policy)
518 {
519 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
522 dprintk("acpi_cpufreq_cpu_exit\n");
524 if (data) {
525 cpufreq_frequency_table_put_attr(policy->cpu);
526 acpi_io_data[policy->cpu] = NULL;
527 acpi_processor_unregister_performance(data->acpi_data, policy->cpu);
528 kfree(data);
529 }
531 return (0);
532 }
534 static int
535 acpi_cpufreq_resume (
536 struct cpufreq_policy *policy)
537 {
538 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
541 dprintk("acpi_cpufreq_resume\n");
543 data->resume = 1;
545 return (0);
546 }
549 static struct freq_attr* acpi_cpufreq_attr[] = {
550 &cpufreq_freq_attr_scaling_available_freqs,
551 NULL,
552 };
554 static struct cpufreq_driver acpi_cpufreq_driver = {
555 .verify = acpi_cpufreq_verify,
556 .target = acpi_cpufreq_target,
557 .init = acpi_cpufreq_cpu_init,
558 .exit = acpi_cpufreq_cpu_exit,
559 .resume = acpi_cpufreq_resume,
560 .name = "acpi-cpufreq",
561 .owner = THIS_MODULE,
562 .attr = acpi_cpufreq_attr,
563 };
566 static int __init
567 acpi_cpufreq_init (void)
568 {
569 dprintk("acpi_cpufreq_init\n");
571 /*
572 * This effectively blocks in-kernel cpufreq driver to interfere
573 * external control logic
574 */
575 if (processor_pmperf_external()) {
576 printk("CPUFREQ is controllerd externally...exit then!\n");
577 return -1;
578 }
580 acpi_cpufreq_early_init_acpi();
582 return cpufreq_register_driver(&acpi_cpufreq_driver);
583 }
586 static void __exit
587 acpi_cpufreq_exit (void)
588 {
589 unsigned int i;
590 dprintk("acpi_cpufreq_exit\n");
592 cpufreq_unregister_driver(&acpi_cpufreq_driver);
594 for_each_possible_cpu(i) {
595 kfree(acpi_perf_data[i]);
596 acpi_perf_data[i] = NULL;
597 }
598 return;
599 }
601 module_param(acpi_pstate_strict, uint, 0644);
602 MODULE_PARM_DESC(acpi_pstate_strict, "value 0 or non-zero. non-zero -> strict ACPI checks are performed during frequency changes.");
604 late_initcall(acpi_cpufreq_init);
605 module_exit(acpi_cpufreq_exit);
607 MODULE_ALIAS("acpi");