ia64/linux-2.6.18-xen.hg

view drivers/acpi/processor_idle.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 831230e53067
children e97855b90cc2
line source
1 /*
2 * processor_idle - idle state submodule to 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, 2005 Dominik Brodowski <linux@brodo.de>
7 * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
8 * - Added processor hotplug support
9 * Copyright (C) 2005 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
10 * - Added support for C3 on SMP
11 *
12 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or (at
17 * your option) any later version.
18 *
19 * This program is distributed in the hope that it will be useful, but
20 * WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22 * General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License along
25 * with this program; if not, write to the Free Software Foundation, Inc.,
26 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
27 *
28 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
29 */
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/init.h>
34 #include <linux/cpufreq.h>
35 #include <linux/proc_fs.h>
36 #include <linux/seq_file.h>
37 #include <linux/acpi.h>
38 #include <linux/dmi.h>
39 #include <linux/moduleparam.h>
40 #include <linux/sched.h> /* need_resched() */
42 #include <asm/io.h>
43 #include <asm/uaccess.h>
45 #include <acpi/acpi_bus.h>
46 #include <acpi/processor.h>
48 #define ACPI_PROCESSOR_COMPONENT 0x01000000
49 #define ACPI_PROCESSOR_CLASS "processor"
50 #define ACPI_PROCESSOR_DRIVER_NAME "ACPI Processor Driver"
51 #define _COMPONENT ACPI_PROCESSOR_COMPONENT
52 ACPI_MODULE_NAME("acpi_processor")
53 #define ACPI_PROCESSOR_FILE_POWER "power"
54 #define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
55 #define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */
56 #define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */
57 static void (*pm_idle_save) (void) __read_mostly;
58 module_param(max_cstate, uint, 0644);
60 static unsigned int nocst __read_mostly;
61 module_param(nocst, uint, 0000);
63 /*
64 * bm_history -- bit-mask with a bit per jiffy of bus-master activity
65 * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
66 * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
67 * 100 HZ: 0x0000000F: 4 jiffies = 40ms
68 * reduce history for more aggressive entry into C3
69 */
70 static unsigned int bm_history __read_mostly =
71 (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
72 module_param(bm_history, uint, 0644);
73 /* --------------------------------------------------------------------------
74 Power Management
75 -------------------------------------------------------------------------- */
77 /*
78 * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
79 * For now disable this. Probably a bug somewhere else.
80 *
81 * To skip this limit, boot/load with a large max_cstate limit.
82 */
83 static int set_max_cstate(struct dmi_system_id *id)
84 {
85 if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
86 return 0;
88 printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate."
89 " Override with \"processor.max_cstate=%d\"\n", id->ident,
90 (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
92 max_cstate = (long)id->driver_data;
94 return 0;
95 }
97 /* Actually this shouldn't be __cpuinitdata, would be better to fix the
98 callers to only run once -AK */
99 static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = {
100 { set_max_cstate, "IBM ThinkPad R40e", {
101 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
102 DMI_MATCH(DMI_BIOS_VERSION,"1SET70WW")}, (void *)1},
103 { set_max_cstate, "IBM ThinkPad R40e", {
104 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
105 DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW")}, (void *)1},
106 { set_max_cstate, "IBM ThinkPad R40e", {
107 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
108 DMI_MATCH(DMI_BIOS_VERSION,"1SET43WW") }, (void*)1},
109 { set_max_cstate, "IBM ThinkPad R40e", {
110 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
111 DMI_MATCH(DMI_BIOS_VERSION,"1SET45WW") }, (void*)1},
112 { set_max_cstate, "IBM ThinkPad R40e", {
113 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
114 DMI_MATCH(DMI_BIOS_VERSION,"1SET47WW") }, (void*)1},
115 { set_max_cstate, "IBM ThinkPad R40e", {
116 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
117 DMI_MATCH(DMI_BIOS_VERSION,"1SET50WW") }, (void*)1},
118 { set_max_cstate, "IBM ThinkPad R40e", {
119 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
120 DMI_MATCH(DMI_BIOS_VERSION,"1SET52WW") }, (void*)1},
121 { set_max_cstate, "IBM ThinkPad R40e", {
122 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
123 DMI_MATCH(DMI_BIOS_VERSION,"1SET55WW") }, (void*)1},
124 { set_max_cstate, "IBM ThinkPad R40e", {
125 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
126 DMI_MATCH(DMI_BIOS_VERSION,"1SET56WW") }, (void*)1},
127 { set_max_cstate, "IBM ThinkPad R40e", {
128 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
129 DMI_MATCH(DMI_BIOS_VERSION,"1SET59WW") }, (void*)1},
130 { set_max_cstate, "IBM ThinkPad R40e", {
131 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
132 DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }, (void*)1},
133 { set_max_cstate, "IBM ThinkPad R40e", {
134 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
135 DMI_MATCH(DMI_BIOS_VERSION,"1SET61WW") }, (void*)1},
136 { set_max_cstate, "IBM ThinkPad R40e", {
137 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
138 DMI_MATCH(DMI_BIOS_VERSION,"1SET62WW") }, (void*)1},
139 { set_max_cstate, "IBM ThinkPad R40e", {
140 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
141 DMI_MATCH(DMI_BIOS_VERSION,"1SET64WW") }, (void*)1},
142 { set_max_cstate, "IBM ThinkPad R40e", {
143 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
144 DMI_MATCH(DMI_BIOS_VERSION,"1SET65WW") }, (void*)1},
145 { set_max_cstate, "IBM ThinkPad R40e", {
146 DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
147 DMI_MATCH(DMI_BIOS_VERSION,"1SET68WW") }, (void*)1},
148 { set_max_cstate, "Medion 41700", {
149 DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
150 DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J")}, (void *)1},
151 { set_max_cstate, "Clevo 5600D", {
152 DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
153 DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
154 (void *)2},
155 {},
156 };
158 static inline u32 ticks_elapsed(u32 t1, u32 t2)
159 {
160 if (t2 >= t1)
161 return (t2 - t1);
162 else if (!acpi_fadt.tmr_val_ext)
163 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
164 else
165 return ((0xFFFFFFFF - t1) + t2);
166 }
168 static void
169 acpi_processor_power_activate(struct acpi_processor *pr,
170 struct acpi_processor_cx *new)
171 {
172 struct acpi_processor_cx *old;
174 if (!pr || !new)
175 return;
177 old = pr->power.state;
179 if (old)
180 old->promotion.count = 0;
181 new->demotion.count = 0;
183 /* Cleanup from old state. */
184 if (old) {
185 switch (old->type) {
186 case ACPI_STATE_C3:
187 /* Disable bus master reload */
188 if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
189 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0,
190 ACPI_MTX_DO_NOT_LOCK);
191 break;
192 }
193 }
195 /* Prepare to use new state. */
196 switch (new->type) {
197 case ACPI_STATE_C3:
198 /* Enable bus master reload */
199 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
200 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1,
201 ACPI_MTX_DO_NOT_LOCK);
202 break;
203 }
205 pr->power.state = new;
207 return;
208 }
210 static void acpi_safe_halt(void)
211 {
212 current_thread_info()->status &= ~TS_POLLING;
213 smp_mb__after_clear_bit();
214 if (!need_resched())
215 safe_halt();
216 current_thread_info()->status |= TS_POLLING;
217 }
219 static atomic_t c3_cpu_count;
221 static void acpi_processor_idle(void)
222 {
223 struct acpi_processor *pr = NULL;
224 struct acpi_processor_cx *cx = NULL;
225 struct acpi_processor_cx *next_state = NULL;
226 int sleep_ticks = 0;
227 u32 t1, t2 = 0;
229 pr = processors[smp_processor_id()];
230 if (!pr)
231 return;
233 /*
234 * Interrupts must be disabled during bus mastering calculations and
235 * for C2/C3 transitions.
236 */
237 local_irq_disable();
239 /*
240 * Check whether we truly need to go idle, or should
241 * reschedule:
242 */
243 if (unlikely(need_resched())) {
244 local_irq_enable();
245 return;
246 }
248 cx = pr->power.state;
249 if (!cx) {
250 if (pm_idle_save)
251 pm_idle_save();
252 else
253 acpi_safe_halt();
254 return;
255 }
257 /*
258 * Check BM Activity
259 * -----------------
260 * Check for bus mastering activity (if required), record, and check
261 * for demotion.
262 */
263 if (pr->flags.bm_check) {
264 u32 bm_status = 0;
265 unsigned long diff = jiffies - pr->power.bm_check_timestamp;
267 if (diff > 31)
268 diff = 31;
270 pr->power.bm_activity <<= diff;
272 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
273 &bm_status, ACPI_MTX_DO_NOT_LOCK);
274 if (bm_status) {
275 pr->power.bm_activity |= 0x1;
276 acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS,
277 1, ACPI_MTX_DO_NOT_LOCK);
278 }
279 /*
280 * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
281 * the true state of bus mastering activity; forcing us to
282 * manually check the BMIDEA bit of each IDE channel.
283 */
284 else if (errata.piix4.bmisx) {
285 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
286 || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
287 pr->power.bm_activity |= 0x1;
288 }
290 pr->power.bm_check_timestamp = jiffies;
292 /*
293 * If bus mastering is or was active this jiffy, demote
294 * to avoid a faulty transition. Note that the processor
295 * won't enter a low-power state during this call (to this
296 * function) but should upon the next.
297 *
298 * TBD: A better policy might be to fallback to the demotion
299 * state (use it for this quantum only) istead of
300 * demoting -- and rely on duration as our sole demotion
301 * qualification. This may, however, introduce DMA
302 * issues (e.g. floppy DMA transfer overrun/underrun).
303 */
304 if ((pr->power.bm_activity & 0x1) &&
305 cx->demotion.threshold.bm) {
306 local_irq_enable();
307 next_state = cx->demotion.state;
308 goto end;
309 }
310 }
312 #ifdef CONFIG_HOTPLUG_CPU
313 /*
314 * Check for P_LVL2_UP flag before entering C2 and above on
315 * an SMP system. We do it here instead of doing it at _CST/P_LVL
316 * detection phase, to work cleanly with logical CPU hotplug.
317 */
318 if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
319 !pr->flags.has_cst && !acpi_fadt.plvl2_up)
320 cx = &pr->power.states[ACPI_STATE_C1];
321 #endif
323 /*
324 * Sleep:
325 * ------
326 * Invoke the current Cx state to put the processor to sleep.
327 */
328 if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
329 current_thread_info()->status &= ~TS_POLLING;
330 smp_mb__after_clear_bit();
331 if (need_resched()) {
332 current_thread_info()->status |= TS_POLLING;
333 local_irq_enable();
334 return;
335 }
336 }
338 switch (cx->type) {
340 case ACPI_STATE_C1:
341 /*
342 * Invoke C1.
343 * Use the appropriate idle routine, the one that would
344 * be used without acpi C-states.
345 */
346 if (pm_idle_save)
347 pm_idle_save();
348 else
349 acpi_safe_halt();
351 /*
352 * TBD: Can't get time duration while in C1, as resumes
353 * go to an ISR rather than here. Need to instrument
354 * base interrupt handler.
355 */
356 sleep_ticks = 0xFFFFFFFF;
357 break;
359 case ACPI_STATE_C2:
360 /* Get start time (ticks) */
361 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
362 /* Invoke C2 */
363 inb(cx->address);
364 /* Dummy wait op - must do something useless after P_LVL2 read
365 because chipsets cannot guarantee that STPCLK# signal
366 gets asserted in time to freeze execution properly. */
367 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
368 /* Get end time (ticks) */
369 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
371 #ifdef CONFIG_GENERIC_TIME
372 /* TSC halts in C2, so notify users */
373 mark_tsc_unstable();
374 #endif
375 /* Re-enable interrupts */
376 local_irq_enable();
377 current_thread_info()->status |= TS_POLLING;
378 /* Compute time (ticks) that we were actually asleep */
379 sleep_ticks =
380 ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
381 break;
383 case ACPI_STATE_C3:
385 if (pr->flags.bm_check) {
386 if (atomic_inc_return(&c3_cpu_count) ==
387 num_online_cpus()) {
388 /*
389 * All CPUs are trying to go to C3
390 * Disable bus master arbitration
391 */
392 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1,
393 ACPI_MTX_DO_NOT_LOCK);
394 }
395 } else {
396 /* SMP with no shared cache... Invalidate cache */
397 ACPI_FLUSH_CPU_CACHE();
398 }
400 /* Get start time (ticks) */
401 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
402 /* Invoke C3 */
403 inb(cx->address);
404 /* Dummy wait op (see above) */
405 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
406 /* Get end time (ticks) */
407 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
408 if (pr->flags.bm_check) {
409 /* Enable bus master arbitration */
410 atomic_dec(&c3_cpu_count);
411 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0,
412 ACPI_MTX_DO_NOT_LOCK);
413 }
415 #ifdef CONFIG_GENERIC_TIME
416 /* TSC halts in C3, so notify users */
417 mark_tsc_unstable();
418 #endif
419 /* Re-enable interrupts */
420 local_irq_enable();
421 current_thread_info()->status |= TS_POLLING;
422 /* Compute time (ticks) that we were actually asleep */
423 sleep_ticks =
424 ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
425 break;
427 default:
428 local_irq_enable();
429 return;
430 }
431 cx->usage++;
432 if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
433 cx->time += sleep_ticks;
435 next_state = pr->power.state;
437 #ifdef CONFIG_HOTPLUG_CPU
438 /* Don't do promotion/demotion */
439 if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
440 !pr->flags.has_cst && !acpi_fadt.plvl2_up) {
441 next_state = cx;
442 goto end;
443 }
444 #endif
446 /*
447 * Promotion?
448 * ----------
449 * Track the number of longs (time asleep is greater than threshold)
450 * and promote when the count threshold is reached. Note that bus
451 * mastering activity may prevent promotions.
452 * Do not promote above max_cstate.
453 */
454 if (cx->promotion.state &&
455 ((cx->promotion.state - pr->power.states) <= max_cstate)) {
456 if (sleep_ticks > cx->promotion.threshold.ticks) {
457 cx->promotion.count++;
458 cx->demotion.count = 0;
459 if (cx->promotion.count >=
460 cx->promotion.threshold.count) {
461 if (pr->flags.bm_check) {
462 if (!
463 (pr->power.bm_activity & cx->
464 promotion.threshold.bm)) {
465 next_state =
466 cx->promotion.state;
467 goto end;
468 }
469 } else {
470 next_state = cx->promotion.state;
471 goto end;
472 }
473 }
474 }
475 }
477 /*
478 * Demotion?
479 * ---------
480 * Track the number of shorts (time asleep is less than time threshold)
481 * and demote when the usage threshold is reached.
482 */
483 if (cx->demotion.state) {
484 if (sleep_ticks < cx->demotion.threshold.ticks) {
485 cx->demotion.count++;
486 cx->promotion.count = 0;
487 if (cx->demotion.count >= cx->demotion.threshold.count) {
488 next_state = cx->demotion.state;
489 goto end;
490 }
491 }
492 }
494 end:
495 /*
496 * Demote if current state exceeds max_cstate
497 */
498 if ((pr->power.state - pr->power.states) > max_cstate) {
499 if (cx->demotion.state)
500 next_state = cx->demotion.state;
501 }
503 /*
504 * New Cx State?
505 * -------------
506 * If we're going to start using a new Cx state we must clean up
507 * from the previous and prepare to use the new.
508 */
509 if (next_state != pr->power.state)
510 acpi_processor_power_activate(pr, next_state);
511 }
513 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
514 {
515 unsigned int i;
516 unsigned int state_is_set = 0;
517 struct acpi_processor_cx *lower = NULL;
518 struct acpi_processor_cx *higher = NULL;
519 struct acpi_processor_cx *cx;
522 if (!pr)
523 return -EINVAL;
525 /*
526 * This function sets the default Cx state policy (OS idle handler).
527 * Our scheme is to promote quickly to C2 but more conservatively
528 * to C3. We're favoring C2 for its characteristics of low latency
529 * (quick response), good power savings, and ability to allow bus
530 * mastering activity. Note that the Cx state policy is completely
531 * customizable and can be altered dynamically.
532 */
534 /* startup state */
535 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
536 cx = &pr->power.states[i];
537 if (!cx->valid)
538 continue;
540 if (!state_is_set)
541 pr->power.state = cx;
542 state_is_set++;
543 break;
544 }
546 if (!state_is_set)
547 return -ENODEV;
549 /* demotion */
550 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
551 cx = &pr->power.states[i];
552 if (!cx->valid)
553 continue;
555 if (lower) {
556 cx->demotion.state = lower;
557 cx->demotion.threshold.ticks = cx->latency_ticks;
558 cx->demotion.threshold.count = 1;
559 if (cx->type == ACPI_STATE_C3)
560 cx->demotion.threshold.bm = bm_history;
561 }
563 lower = cx;
564 }
566 /* promotion */
567 for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
568 cx = &pr->power.states[i];
569 if (!cx->valid)
570 continue;
572 if (higher) {
573 cx->promotion.state = higher;
574 cx->promotion.threshold.ticks = cx->latency_ticks;
575 if (cx->type >= ACPI_STATE_C2)
576 cx->promotion.threshold.count = 4;
577 else
578 cx->promotion.threshold.count = 10;
579 if (higher->type == ACPI_STATE_C3)
580 cx->promotion.threshold.bm = bm_history;
581 }
583 higher = cx;
584 }
586 return 0;
587 }
589 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
590 {
592 if (!pr)
593 return -EINVAL;
595 if (!pr->pblk)
596 return -ENODEV;
598 /* if info is obtained from pblk/fadt, type equals state */
599 pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
600 pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
602 #ifndef CONFIG_HOTPLUG_CPU
603 /*
604 * Check for P_LVL2_UP flag before entering C2 and above on
605 * an SMP system.
606 */
607 if ((num_online_cpus() > 1) && !acpi_fadt.plvl2_up)
608 return -ENODEV;
609 #endif
611 /* determine C2 and C3 address from pblk */
612 pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
613 pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
615 /* determine latencies from FADT */
616 pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat;
617 pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;
619 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
620 "lvl2[0x%08x] lvl3[0x%08x]\n",
621 pr->power.states[ACPI_STATE_C2].address,
622 pr->power.states[ACPI_STATE_C3].address));
624 return 0;
625 }
627 static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr)
628 {
630 /* Zero initialize all the C-states info. */
631 memset(pr->power.states, 0, sizeof(pr->power.states));
633 /* set the first C-State to C1 */
634 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
636 /* the C0 state only exists as a filler in our array,
637 * and all processors need to support C1 */
638 pr->power.states[ACPI_STATE_C0].valid = 1;
639 pr->power.states[ACPI_STATE_C1].valid = 1;
641 return 0;
642 }
644 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
645 {
646 acpi_status status = 0;
647 acpi_integer count;
648 int current_count;
649 int i;
650 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
651 union acpi_object *cst;
654 if (nocst)
655 return -ENODEV;
657 current_count = 1;
659 /* Zero initialize C2 onwards and prepare for fresh CST lookup */
660 for (i = 2; i < ACPI_PROCESSOR_MAX_POWER; i++)
661 memset(&(pr->power.states[i]), 0,
662 sizeof(struct acpi_processor_cx));
664 status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
665 if (ACPI_FAILURE(status)) {
666 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
667 return -ENODEV;
668 }
670 cst = (union acpi_object *)buffer.pointer;
672 /* There must be at least 2 elements */
673 if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
674 printk(KERN_ERR PREFIX "not enough elements in _CST\n");
675 status = -EFAULT;
676 goto end;
677 }
679 count = cst->package.elements[0].integer.value;
681 /* Validate number of power states. */
682 if (count < 1 || count != cst->package.count - 1) {
683 printk(KERN_ERR PREFIX "count given by _CST is not valid\n");
684 status = -EFAULT;
685 goto end;
686 }
688 /* Tell driver that at least _CST is supported. */
689 pr->flags.has_cst = 1;
691 for (i = 1; i <= count; i++) {
692 union acpi_object *element;
693 union acpi_object *obj;
694 struct acpi_power_register *reg;
695 struct acpi_processor_cx cx;
697 memset(&cx, 0, sizeof(cx));
699 element = (union acpi_object *)&(cst->package.elements[i]);
700 if (element->type != ACPI_TYPE_PACKAGE)
701 continue;
703 if (element->package.count != 4)
704 continue;
706 obj = (union acpi_object *)&(element->package.elements[0]);
708 if (obj->type != ACPI_TYPE_BUFFER)
709 continue;
711 reg = (struct acpi_power_register *)obj->buffer.pointer;
713 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
714 (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
715 continue;
717 cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ?
718 0 : reg->address;
720 /* There should be an easy way to extract an integer... */
721 obj = (union acpi_object *)&(element->package.elements[1]);
722 if (obj->type != ACPI_TYPE_INTEGER)
723 continue;
725 cx.type = obj->integer.value;
727 if ((cx.type != ACPI_STATE_C1) &&
728 (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
729 continue;
731 if ((cx.type < ACPI_STATE_C2) || (cx.type > ACPI_STATE_C3))
732 continue;
734 obj = (union acpi_object *)&(element->package.elements[2]);
735 if (obj->type != ACPI_TYPE_INTEGER)
736 continue;
738 cx.latency = obj->integer.value;
740 obj = (union acpi_object *)&(element->package.elements[3]);
741 if (obj->type != ACPI_TYPE_INTEGER)
742 continue;
744 cx.power = obj->integer.value;
746 current_count++;
747 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
749 /*
750 * We support total ACPI_PROCESSOR_MAX_POWER - 1
751 * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
752 */
753 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
754 printk(KERN_WARNING
755 "Limiting number of power states to max (%d)\n",
756 ACPI_PROCESSOR_MAX_POWER);
757 printk(KERN_WARNING
758 "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
759 break;
760 }
761 }
763 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
764 current_count));
766 /* Validate number of power states discovered */
767 if (current_count < 2)
768 status = -EFAULT;
770 end:
771 kfree(buffer.pointer);
773 return status;
774 }
776 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
777 {
779 if (!cx->address)
780 return;
782 /*
783 * C2 latency must be less than or equal to 100
784 * microseconds.
785 */
786 else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
787 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
788 "latency too large [%d]\n", cx->latency));
789 return;
790 }
792 /*
793 * Otherwise we've met all of our C2 requirements.
794 * Normalize the C2 latency to expidite policy
795 */
796 cx->valid = 1;
797 cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
799 return;
800 }
802 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
803 struct acpi_processor_cx *cx)
804 {
805 static int bm_check_flag;
808 if (!cx->address)
809 return;
811 /*
812 * C3 latency must be less than or equal to 1000
813 * microseconds.
814 */
815 else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
816 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
817 "latency too large [%d]\n", cx->latency));
818 return;
819 }
821 /*
822 * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
823 * DMA transfers are used by any ISA device to avoid livelock.
824 * Note that we could disable Type-F DMA (as recommended by
825 * the erratum), but this is known to disrupt certain ISA
826 * devices thus we take the conservative approach.
827 */
828 else if (errata.piix4.fdma) {
829 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
830 "C3 not supported on PIIX4 with Type-F DMA\n"));
831 return;
832 }
834 /* All the logic here assumes flags.bm_check is same across all CPUs */
835 if (!bm_check_flag) {
836 /* Determine whether bm_check is needed based on CPU */
837 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
838 bm_check_flag = pr->flags.bm_check;
839 } else {
840 pr->flags.bm_check = bm_check_flag;
841 }
843 if (pr->flags.bm_check) {
844 /* bus mastering control is necessary */
845 if (!pr->flags.bm_control) {
846 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
847 "C3 support requires bus mastering control\n"));
848 return;
849 }
850 } else {
851 /*
852 * WBINVD should be set in fadt, for C3 state to be
853 * supported on when bm_check is not required.
854 */
855 if (acpi_fadt.wb_invd != 1) {
856 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
857 "Cache invalidation should work properly"
858 " for C3 to be enabled on SMP systems\n"));
859 return;
860 }
861 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD,
862 0, ACPI_MTX_DO_NOT_LOCK);
863 }
865 /*
866 * Otherwise we've met all of our C3 requirements.
867 * Normalize the C3 latency to expidite policy. Enable
868 * checking of bus mastering status (bm_check) so we can
869 * use this in our C3 policy
870 */
871 cx->valid = 1;
872 cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
874 return;
875 }
877 static int acpi_processor_power_verify(struct acpi_processor *pr)
878 {
879 unsigned int i;
880 unsigned int working = 0;
882 #ifdef ARCH_APICTIMER_STOPS_ON_C3
883 int timer_broadcast = 0;
884 cpumask_t mask = cpumask_of_cpu(pr->id);
885 on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
886 #endif
888 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
889 struct acpi_processor_cx *cx = &pr->power.states[i];
891 switch (cx->type) {
892 case ACPI_STATE_C1:
893 cx->valid = 1;
894 break;
896 case ACPI_STATE_C2:
897 acpi_processor_power_verify_c2(cx);
898 #ifdef ARCH_APICTIMER_STOPS_ON_C3
899 /* Some AMD systems fake C3 as C2, but still
900 have timer troubles */
901 if (cx->valid &&
902 boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
903 timer_broadcast++;
904 #endif
905 break;
907 case ACPI_STATE_C3:
908 acpi_processor_power_verify_c3(pr, cx);
909 #ifdef ARCH_APICTIMER_STOPS_ON_C3
910 if (cx->valid)
911 timer_broadcast++;
912 #endif
913 break;
914 }
916 if (cx->valid)
917 working++;
918 }
920 #ifdef ARCH_APICTIMER_STOPS_ON_C3
921 if (timer_broadcast)
922 on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);
923 #endif
925 return (working);
926 }
928 static int acpi_processor_get_power_info(struct acpi_processor *pr)
929 {
930 unsigned int i;
931 int result;
934 /* NOTE: the idle thread may not be running while calling
935 * this function */
937 /* Adding C1 state */
938 acpi_processor_get_power_info_default_c1(pr);
939 result = acpi_processor_get_power_info_cst(pr);
940 if (result == -ENODEV)
941 acpi_processor_get_power_info_fadt(pr);
943 pr->power.count = acpi_processor_power_verify(pr);
945 /*
946 * Set Default Policy
947 * ------------------
948 * Now that we know which states are supported, set the default
949 * policy. Note that this policy can be changed dynamically
950 * (e.g. encourage deeper sleeps to conserve battery life when
951 * not on AC).
952 */
953 result = acpi_processor_set_power_policy(pr);
954 if (result)
955 return result;
957 /*
958 * if one state of type C2 or C3 is available, mark this
959 * CPU as being "idle manageable"
960 */
961 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
962 if (pr->power.states[i].valid) {
963 pr->power.count = i;
964 if (pr->power.states[i].type >= ACPI_STATE_C2)
965 pr->flags.power = 1;
966 }
967 }
969 return 0;
970 }
972 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
973 {
974 int result = 0;
977 if (!pr)
978 return -EINVAL;
980 if (nocst) {
981 return -ENODEV;
982 }
984 if (!pr->flags.power_setup_done)
985 return -ENODEV;
987 /* Fall back to the default idle loop */
988 if (!processor_pm_external())
989 pm_idle = pm_idle_save;
990 synchronize_sched(); /* Relies on interrupts forcing exit from idle. */
992 pr->flags.power = 0;
993 result = acpi_processor_get_power_info(pr);
994 if (processor_pm_external())
995 processor_notify_external(pr,
996 PROCESSOR_PM_CHANGE, PM_TYPE_IDLE);
997 else if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
998 pm_idle = acpi_processor_idle;
1000 return result;
1003 /* proc interface */
1005 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
1007 struct acpi_processor *pr = (struct acpi_processor *)seq->private;
1008 unsigned int i;
1011 if (!pr)
1012 goto end;
1014 seq_printf(seq, "active state: C%zd\n"
1015 "max_cstate: C%d\n"
1016 "bus master activity: %08x\n",
1017 pr->power.state ? pr->power.state - pr->power.states : 0,
1018 max_cstate, (unsigned)pr->power.bm_activity);
1020 seq_puts(seq, "states:\n");
1022 for (i = 1; i <= pr->power.count; i++) {
1023 seq_printf(seq, " %cC%d: ",
1024 (&pr->power.states[i] ==
1025 pr->power.state ? '*' : ' '), i);
1027 if (!pr->power.states[i].valid) {
1028 seq_puts(seq, "<not supported>\n");
1029 continue;
1032 switch (pr->power.states[i].type) {
1033 case ACPI_STATE_C1:
1034 seq_printf(seq, "type[C1] ");
1035 break;
1036 case ACPI_STATE_C2:
1037 seq_printf(seq, "type[C2] ");
1038 break;
1039 case ACPI_STATE_C3:
1040 seq_printf(seq, "type[C3] ");
1041 break;
1042 default:
1043 seq_printf(seq, "type[--] ");
1044 break;
1047 if (pr->power.states[i].promotion.state)
1048 seq_printf(seq, "promotion[C%zd] ",
1049 (pr->power.states[i].promotion.state -
1050 pr->power.states));
1051 else
1052 seq_puts(seq, "promotion[--] ");
1054 if (pr->power.states[i].demotion.state)
1055 seq_printf(seq, "demotion[C%zd] ",
1056 (pr->power.states[i].demotion.state -
1057 pr->power.states));
1058 else
1059 seq_puts(seq, "demotion[--] ");
1061 seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n",
1062 pr->power.states[i].latency,
1063 pr->power.states[i].usage,
1064 pr->power.states[i].time);
1067 end:
1068 return 0;
1071 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
1073 return single_open(file, acpi_processor_power_seq_show,
1074 PDE(inode)->data);
1077 static const struct file_operations acpi_processor_power_fops = {
1078 .open = acpi_processor_power_open_fs,
1079 .read = seq_read,
1080 .llseek = seq_lseek,
1081 .release = single_release,
1082 };
1084 int acpi_processor_power_init(struct acpi_processor *pr,
1085 struct acpi_device *device)
1087 acpi_status status = 0;
1088 static int first_run;
1089 struct proc_dir_entry *entry = NULL;
1090 unsigned int i;
1093 if (!first_run) {
1094 dmi_check_system(processor_power_dmi_table);
1095 if (max_cstate < ACPI_C_STATES_MAX)
1096 printk(KERN_NOTICE
1097 "ACPI: processor limited to max C-state %d\n",
1098 max_cstate);
1099 first_run++;
1102 if (!pr)
1103 return -EINVAL;
1105 if (acpi_fadt.cst_cnt && !nocst) {
1106 status =
1107 acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
1108 if (ACPI_FAILURE(status)) {
1109 ACPI_EXCEPTION((AE_INFO, status,
1110 "Notifying BIOS of _CST ability failed"));
1114 acpi_processor_get_power_info(pr);
1116 /*
1117 * Install the idle handler if processor power management is supported.
1118 * Note that we use previously set idle handler will be used on
1119 * platforms that only support C1.
1120 */
1121 if ((pr->flags.power) && (!boot_option_idle_override)) {
1122 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1123 for (i = 1; i <= pr->power.count; i++)
1124 if (pr->power.states[i].valid)
1125 printk(" C%d[C%d]", i,
1126 pr->power.states[i].type);
1127 printk(")\n");
1129 if (!processor_pm_external() && (pr->id == 0)) {
1130 pm_idle_save = pm_idle;
1131 pm_idle = acpi_processor_idle;
1135 /* 'power' [R] */
1136 entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1137 S_IRUGO, acpi_device_dir(device));
1138 if (!entry)
1139 return -EIO;
1140 else {
1141 entry->proc_fops = &acpi_processor_power_fops;
1142 entry->data = acpi_driver_data(device);
1143 entry->owner = THIS_MODULE;
1146 pr->flags.power_setup_done = 1;
1148 if (processor_pm_external())
1149 processor_notify_external(pr,
1150 PROCESSOR_PM_INIT, PM_TYPE_IDLE);
1151 return 0;
1154 int acpi_processor_power_exit(struct acpi_processor *pr,
1155 struct acpi_device *device)
1158 pr->flags.power_setup_done = 0;
1160 if (acpi_device_dir(device))
1161 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1162 acpi_device_dir(device));
1164 /* Unregister the idle handler when processor #0 is removed. */
1165 if (pr->id == 0) {
1166 pm_idle = pm_idle_save;
1168 /*
1169 * We are about to unload the current idle thread pm callback
1170 * (pm_idle), Wait for all processors to update cached/local
1171 * copies of pm_idle before proceeding.
1172 */
1173 cpu_idle_wait();
1176 return 0;