ia64/linux-2.6.18-xen.hg

view drivers/acpi/processor_idle.c @ 912:dd42cdb0ab89

[IA64] Build blktap2 driver by default in x86 builds.

add CONFIG_XEN_BLKDEV_TAP2=y to buildconfigs/linux-defconfig_xen_ia64.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
author Isaku Yamahata <yamahata@valinux.co.jp>
date Mon Jun 29 12:09:16 2009 +0900 (2009-06-29)
parents ff9683032b76
children
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 = 0;
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 if (!processor_pm_external())
718 cx.address = (reg->space_id ==
719 ACPI_ADR_SPACE_FIXED_HARDWARE) ?
720 0 : reg->address;
721 else
722 cx.address = reg->address;
724 /* There should be an easy way to extract an integer... */
725 obj = (union acpi_object *)&(element->package.elements[1]);
726 if (obj->type != ACPI_TYPE_INTEGER)
727 continue;
729 cx.type = obj->integer.value;
731 /*
732 * Some buggy BIOSes won't list C1 in _CST -
733 * Let acpi_processor_get_power_info_default() handle them later
734 */
735 if (i == 1 && cx.type != ACPI_STATE_C1)
736 current_count++;
738 /* Following check doesn't apply to external control case */
739 if (!processor_pm_external() &&
740 (cx.type != ACPI_STATE_C1) &&
741 (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
742 continue;
744 obj = (union acpi_object *)&(element->package.elements[2]);
745 if (obj->type != ACPI_TYPE_INTEGER)
746 continue;
748 cx.latency = obj->integer.value;
750 obj = (union acpi_object *)&(element->package.elements[3]);
751 if (obj->type != ACPI_TYPE_INTEGER)
752 continue;
754 cx.power = obj->integer.value;
756 #ifdef CONFIG_PROCESSOR_EXTERNAL_CONTROL
757 /* cache control methods to notify external logic */
758 if (processor_pm_external())
759 memcpy(&cx.reg, reg, sizeof(*reg));
760 #endif
762 current_count++;
763 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
765 /*
766 * We support total ACPI_PROCESSOR_MAX_POWER - 1
767 * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
768 */
769 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
770 printk(KERN_WARNING
771 "Limiting number of power states to max (%d)\n",
772 ACPI_PROCESSOR_MAX_POWER);
773 printk(KERN_WARNING
774 "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
775 break;
776 }
777 }
779 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
780 current_count));
782 /* Validate number of power states discovered */
783 if (current_count < 2)
784 status = -EFAULT;
786 end:
787 kfree(buffer.pointer);
789 return status;
790 }
792 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
793 {
795 if (!cx->address)
796 return;
798 /*
799 * C2 latency must be less than or equal to 100
800 * microseconds.
801 */
802 else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
803 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
804 "latency too large [%d]\n", cx->latency));
805 return;
806 }
808 /*
809 * Otherwise we've met all of our C2 requirements.
810 * Normalize the C2 latency to expidite policy
811 */
812 cx->valid = 1;
813 cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
815 return;
816 }
818 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
819 struct acpi_processor_cx *cx)
820 {
821 static int bm_check_flag;
824 if (!cx->address)
825 return;
827 /*
828 * C3 latency must be less than or equal to 1000
829 * microseconds.
830 */
831 else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
832 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
833 "latency too large [%d]\n", cx->latency));
834 return;
835 }
837 /*
838 * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
839 * DMA transfers are used by any ISA device to avoid livelock.
840 * Note that we could disable Type-F DMA (as recommended by
841 * the erratum), but this is known to disrupt certain ISA
842 * devices thus we take the conservative approach.
843 */
844 else if (errata.piix4.fdma) {
845 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
846 "C3 not supported on PIIX4 with Type-F DMA\n"));
847 return;
848 }
850 /* All the logic here assumes flags.bm_check is same across all CPUs */
851 if (!bm_check_flag) {
852 /* Determine whether bm_check is needed based on CPU */
853 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
854 bm_check_flag = pr->flags.bm_check;
855 } else {
856 pr->flags.bm_check = bm_check_flag;
857 }
859 if (pr->flags.bm_check) {
860 if (!pr->flags.bm_control) {
861 if (pr->flags.has_cst != 1) {
862 /* bus mastering control is necessary */
863 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
864 "C3 support requires BM control\n"));
865 return;
866 } else {
867 /* Here we enter C3 without bus mastering */
868 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
869 "C3 support without BM control\n"));
870 }
871 }
872 } else {
873 /*
874 * WBINVD should be set in fadt, for C3 state to be
875 * supported on when bm_check is not required.
876 */
877 if (acpi_fadt.wb_invd != 1) {
878 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
879 "Cache invalidation should work properly"
880 " for C3 to be enabled on SMP systems\n"));
881 return;
882 }
883 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD,
884 0, ACPI_MTX_DO_NOT_LOCK);
885 }
887 /*
888 * Otherwise we've met all of our C3 requirements.
889 * Normalize the C3 latency to expidite policy. Enable
890 * checking of bus mastering status (bm_check) so we can
891 * use this in our C3 policy
892 */
893 cx->valid = 1;
894 cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
896 return;
897 }
899 static int acpi_processor_power_verify(struct acpi_processor *pr)
900 {
901 unsigned int i;
902 unsigned int working = 0;
904 #ifdef ARCH_APICTIMER_STOPS_ON_C3
905 int timer_broadcast = 0;
906 cpumask_t mask = cpumask_of_cpu(pr->id);
907 on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
908 #endif
910 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
911 struct acpi_processor_cx *cx = &pr->power.states[i];
913 switch (cx->type) {
914 case ACPI_STATE_C1:
915 cx->valid = 1;
916 break;
918 case ACPI_STATE_C2:
919 acpi_processor_power_verify_c2(cx);
920 #ifdef ARCH_APICTIMER_STOPS_ON_C3
921 /* Some AMD systems fake C3 as C2, but still
922 have timer troubles */
923 if (cx->valid &&
924 boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
925 timer_broadcast++;
926 #endif
927 break;
929 case ACPI_STATE_C3:
930 acpi_processor_power_verify_c3(pr, cx);
931 #ifdef ARCH_APICTIMER_STOPS_ON_C3
932 if (cx->valid)
933 timer_broadcast++;
934 #endif
935 break;
936 }
938 if (cx->valid)
939 working++;
940 }
942 #ifdef ARCH_APICTIMER_STOPS_ON_C3
943 if (timer_broadcast)
944 on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);
945 #endif
947 return (working);
948 }
950 static int acpi_processor_get_power_info(struct acpi_processor *pr)
951 {
952 unsigned int i;
953 int result;
956 /* NOTE: the idle thread may not be running while calling
957 * this function */
959 /* Adding C1 state */
960 acpi_processor_get_power_info_default_c1(pr);
961 result = acpi_processor_get_power_info_cst(pr);
962 if (result == -ENODEV)
963 acpi_processor_get_power_info_fadt(pr);
965 pr->power.count = acpi_processor_power_verify(pr);
967 /*
968 * Set Default Policy
969 * ------------------
970 * Now that we know which states are supported, set the default
971 * policy. Note that this policy can be changed dynamically
972 * (e.g. encourage deeper sleeps to conserve battery life when
973 * not on AC).
974 */
975 result = acpi_processor_set_power_policy(pr);
976 if (result)
977 return result;
979 /*
980 * if one state of type C2 or C3 is available, mark this
981 * CPU as being "idle manageable"
982 */
983 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
984 if (pr->power.states[i].valid) {
985 pr->power.count = i;
986 if (pr->power.states[i].type >= ACPI_STATE_C2)
987 pr->flags.power = 1;
988 }
989 }
991 return 0;
992 }
994 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
995 {
996 int result = 0;
999 if (!pr)
1000 return -EINVAL;
1002 if (nocst) {
1003 return -ENODEV;
1006 if (!pr->flags.power_setup_done)
1007 return -ENODEV;
1009 /* Fall back to the default idle loop */
1010 if (!processor_pm_external())
1011 pm_idle = pm_idle_save;
1012 synchronize_sched(); /* Relies on interrupts forcing exit from idle. */
1014 pr->flags.power = 0;
1015 result = acpi_processor_get_power_info(pr);
1016 if (processor_pm_external())
1017 processor_notify_external(pr,
1018 PROCESSOR_PM_CHANGE, PM_TYPE_IDLE);
1019 else if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
1020 pm_idle = acpi_processor_idle;
1022 return result;
1025 /* proc interface */
1027 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
1029 struct acpi_processor *pr = (struct acpi_processor *)seq->private;
1030 unsigned int i;
1033 if (!pr)
1034 goto end;
1036 seq_printf(seq, "active state: C%zd\n"
1037 "max_cstate: C%d\n"
1038 "bus master activity: %08x\n",
1039 pr->power.state ? pr->power.state - pr->power.states : 0,
1040 max_cstate, (unsigned)pr->power.bm_activity);
1042 seq_puts(seq, "states:\n");
1044 for (i = 1; i <= pr->power.count; i++) {
1045 seq_printf(seq, " %cC%d: ",
1046 (&pr->power.states[i] ==
1047 pr->power.state ? '*' : ' '), i);
1049 if (!pr->power.states[i].valid) {
1050 seq_puts(seq, "<not supported>\n");
1051 continue;
1054 switch (pr->power.states[i].type) {
1055 case ACPI_STATE_C1:
1056 seq_printf(seq, "type[C1] ");
1057 break;
1058 case ACPI_STATE_C2:
1059 seq_printf(seq, "type[C2] ");
1060 break;
1061 case ACPI_STATE_C3:
1062 seq_printf(seq, "type[C3] ");
1063 break;
1064 default:
1065 seq_printf(seq, "type[--] ");
1066 break;
1069 if (pr->power.states[i].promotion.state)
1070 seq_printf(seq, "promotion[C%zd] ",
1071 (pr->power.states[i].promotion.state -
1072 pr->power.states));
1073 else
1074 seq_puts(seq, "promotion[--] ");
1076 if (pr->power.states[i].demotion.state)
1077 seq_printf(seq, "demotion[C%zd] ",
1078 (pr->power.states[i].demotion.state -
1079 pr->power.states));
1080 else
1081 seq_puts(seq, "demotion[--] ");
1083 seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n",
1084 pr->power.states[i].latency,
1085 pr->power.states[i].usage,
1086 pr->power.states[i].time);
1089 end:
1090 return 0;
1093 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
1095 return single_open(file, acpi_processor_power_seq_show,
1096 PDE(inode)->data);
1099 static const struct file_operations acpi_processor_power_fops = {
1100 .open = acpi_processor_power_open_fs,
1101 .read = seq_read,
1102 .llseek = seq_lseek,
1103 .release = single_release,
1104 };
1106 int acpi_processor_power_init(struct acpi_processor *pr,
1107 struct acpi_device *device)
1109 acpi_status status = 0;
1110 static int first_run;
1111 struct proc_dir_entry *entry = NULL;
1112 unsigned int i;
1115 if (!first_run) {
1116 dmi_check_system(processor_power_dmi_table);
1117 if (max_cstate < ACPI_C_STATES_MAX)
1118 printk(KERN_NOTICE
1119 "ACPI: processor limited to max C-state %d\n",
1120 max_cstate);
1121 first_run++;
1124 if (!pr)
1125 return -EINVAL;
1127 if (acpi_fadt.cst_cnt && !nocst) {
1128 status =
1129 acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
1130 if (ACPI_FAILURE(status)) {
1131 ACPI_EXCEPTION((AE_INFO, status,
1132 "Notifying BIOS of _CST ability failed"));
1136 acpi_processor_get_power_info(pr);
1138 /*
1139 * Install the idle handler if processor power management is supported.
1140 * Note that we use previously set idle handler will be used on
1141 * platforms that only support C1.
1142 */
1143 if ((pr->flags.power) && (!boot_option_idle_override)) {
1144 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1145 for (i = 1; i <= pr->power.count; i++)
1146 if (pr->power.states[i].valid)
1147 printk(" C%d[C%d]", i,
1148 pr->power.states[i].type);
1149 printk(")\n");
1151 if (!processor_pm_external() && (pr->id == 0)) {
1152 pm_idle_save = pm_idle;
1153 pm_idle = acpi_processor_idle;
1157 /* 'power' [R] */
1158 entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1159 S_IRUGO, acpi_device_dir(device));
1160 if (!entry)
1161 return -EIO;
1162 else {
1163 entry->proc_fops = &acpi_processor_power_fops;
1164 entry->data = acpi_driver_data(device);
1165 entry->owner = THIS_MODULE;
1168 pr->flags.power_setup_done = 1;
1170 if (processor_pm_external())
1171 processor_notify_external(pr,
1172 PROCESSOR_PM_INIT, PM_TYPE_IDLE);
1173 return 0;
1176 int acpi_processor_power_exit(struct acpi_processor *pr,
1177 struct acpi_device *device)
1180 pr->flags.power_setup_done = 0;
1182 if (acpi_device_dir(device))
1183 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1184 acpi_device_dir(device));
1186 /* Unregister the idle handler when processor #0 is removed. */
1187 if (pr->id == 0) {
1188 pm_idle = pm_idle_save;
1190 /*
1191 * We are about to unload the current idle thread pm callback
1192 * (pm_idle), Wait for all processors to update cached/local
1193 * copies of pm_idle before proceeding.
1194 */
1195 cpu_idle_wait();
1198 return 0;