0a395fca843b46686b748ffe1583515cc863e9af
[linux-2.6.git] / drivers / acpi / processor_idle.c
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  */
30
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() */
41 #include <linux/latency.h>
42
43 #include <asm/io.h>
44 #include <asm/uaccess.h>
45
46 #include <acpi/acpi_bus.h>
47 #include <acpi/processor.h>
48
49 #define ACPI_PROCESSOR_COMPONENT        0x01000000
50 #define ACPI_PROCESSOR_CLASS            "processor"
51 #define ACPI_PROCESSOR_DRIVER_NAME      "ACPI Processor Driver"
52 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
53 ACPI_MODULE_NAME("acpi_processor")
54 #define ACPI_PROCESSOR_FILE_POWER       "power"
55 #define US_TO_PM_TIMER_TICKS(t)         ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
56 #define C2_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
57 #define C3_OVERHEAD                     4       /* 1us (3.579 ticks per us) */
58 static void (*pm_idle_save) (void) __read_mostly;
59 module_param(max_cstate, uint, 0644);
60
61 static unsigned int nocst __read_mostly;
62 module_param(nocst, uint, 0000);
63
64 /*
65  * bm_history -- bit-mask with a bit per jiffy of bus-master activity
66  * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
67  * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
68  * 100 HZ: 0x0000000F: 4 jiffies = 40ms
69  * reduce history for more aggressive entry into C3
70  */
71 static unsigned int bm_history __read_mostly =
72     (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
73 module_param(bm_history, uint, 0644);
74 /* --------------------------------------------------------------------------
75                                 Power Management
76    -------------------------------------------------------------------------- */
77
78 /*
79  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
80  * For now disable this. Probably a bug somewhere else.
81  *
82  * To skip this limit, boot/load with a large max_cstate limit.
83  */
84 static int set_max_cstate(struct dmi_system_id *id)
85 {
86         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
87                 return 0;
88
89         printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate."
90                " Override with \"processor.max_cstate=%d\"\n", id->ident,
91                (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
92
93         max_cstate = (long)id->driver_data;
94
95         return 0;
96 }
97
98 /* Actually this shouldn't be __cpuinitdata, would be better to fix the
99    callers to only run once -AK */
100 static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = {
101         { set_max_cstate, "IBM ThinkPad R40e", {
102           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
103           DMI_MATCH(DMI_BIOS_VERSION,"1SET70WW")}, (void *)1},
104         { set_max_cstate, "IBM ThinkPad R40e", {
105           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
106           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW")}, (void *)1},
107         { set_max_cstate, "IBM ThinkPad R40e", {
108           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
109           DMI_MATCH(DMI_BIOS_VERSION,"1SET43WW") }, (void*)1},
110         { set_max_cstate, "IBM ThinkPad R40e", {
111           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
112           DMI_MATCH(DMI_BIOS_VERSION,"1SET45WW") }, (void*)1},
113         { set_max_cstate, "IBM ThinkPad R40e", {
114           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
115           DMI_MATCH(DMI_BIOS_VERSION,"1SET47WW") }, (void*)1},
116         { set_max_cstate, "IBM ThinkPad R40e", {
117           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
118           DMI_MATCH(DMI_BIOS_VERSION,"1SET50WW") }, (void*)1},
119         { set_max_cstate, "IBM ThinkPad R40e", {
120           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
121           DMI_MATCH(DMI_BIOS_VERSION,"1SET52WW") }, (void*)1},
122         { set_max_cstate, "IBM ThinkPad R40e", {
123           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
124           DMI_MATCH(DMI_BIOS_VERSION,"1SET55WW") }, (void*)1},
125         { set_max_cstate, "IBM ThinkPad R40e", {
126           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
127           DMI_MATCH(DMI_BIOS_VERSION,"1SET56WW") }, (void*)1},
128         { set_max_cstate, "IBM ThinkPad R40e", {
129           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
130           DMI_MATCH(DMI_BIOS_VERSION,"1SET59WW") }, (void*)1},
131         { set_max_cstate, "IBM ThinkPad R40e", {
132           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
133           DMI_MATCH(DMI_BIOS_VERSION,"1SET60WW") }, (void*)1},
134         { set_max_cstate, "IBM ThinkPad R40e", {
135           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
136           DMI_MATCH(DMI_BIOS_VERSION,"1SET61WW") }, (void*)1},
137         { set_max_cstate, "IBM ThinkPad R40e", {
138           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
139           DMI_MATCH(DMI_BIOS_VERSION,"1SET62WW") }, (void*)1},
140         { set_max_cstate, "IBM ThinkPad R40e", {
141           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
142           DMI_MATCH(DMI_BIOS_VERSION,"1SET64WW") }, (void*)1},
143         { set_max_cstate, "IBM ThinkPad R40e", {
144           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
145           DMI_MATCH(DMI_BIOS_VERSION,"1SET65WW") }, (void*)1},
146         { set_max_cstate, "IBM ThinkPad R40e", {
147           DMI_MATCH(DMI_BIOS_VENDOR,"IBM"),
148           DMI_MATCH(DMI_BIOS_VERSION,"1SET68WW") }, (void*)1},
149         { set_max_cstate, "Medion 41700", {
150           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
151           DMI_MATCH(DMI_BIOS_VERSION,"R01-A1J")}, (void *)1},
152         { set_max_cstate, "Clevo 5600D", {
153           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
154           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
155          (void *)2},
156         {},
157 };
158
159 static inline u32 ticks_elapsed(u32 t1, u32 t2)
160 {
161         if (t2 >= t1)
162                 return (t2 - t1);
163         else if (!acpi_fadt.tmr_val_ext)
164                 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
165         else
166                 return ((0xFFFFFFFF - t1) + t2);
167 }
168
169 static void
170 acpi_processor_power_activate(struct acpi_processor *pr,
171                               struct acpi_processor_cx *new)
172 {
173         struct acpi_processor_cx *old;
174
175         if (!pr || !new)
176                 return;
177
178         old = pr->power.state;
179
180         if (old)
181                 old->promotion.count = 0;
182         new->demotion.count = 0;
183
184         /* Cleanup from old state. */
185         if (old) {
186                 switch (old->type) {
187                 case ACPI_STATE_C3:
188                         /* Disable bus master reload */
189                         if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
190                                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0,
191                                                   ACPI_MTX_DO_NOT_LOCK);
192                         break;
193                 }
194         }
195
196         /* Prepare to use new state. */
197         switch (new->type) {
198         case ACPI_STATE_C3:
199                 /* Enable bus master reload */
200                 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
201                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1,
202                                           ACPI_MTX_DO_NOT_LOCK);
203                 break;
204         }
205
206         pr->power.state = new;
207
208         return;
209 }
210
211 static void acpi_safe_halt(void)
212 {
213         current_thread_info()->status &= ~TS_POLLING;
214         smp_mb__after_clear_bit();
215         if (!need_resched())
216                 safe_halt();
217         current_thread_info()->status |= TS_POLLING;
218 }
219
220 static atomic_t c3_cpu_count;
221
222 static void acpi_processor_idle(void)
223 {
224         struct acpi_processor *pr = NULL;
225         struct acpi_processor_cx *cx = NULL;
226         struct acpi_processor_cx *next_state = NULL;
227         int sleep_ticks = 0;
228         u32 t1, t2 = 0;
229
230         pr = processors[smp_processor_id()];
231         if (!pr)
232                 return;
233
234         /*
235          * Interrupts must be disabled during bus mastering calculations and
236          * for C2/C3 transitions.
237          */
238         local_irq_disable();
239
240         /*
241          * Check whether we truly need to go idle, or should
242          * reschedule:
243          */
244         if (unlikely(need_resched())) {
245                 local_irq_enable();
246                 return;
247         }
248
249         cx = pr->power.state;
250         if (!cx) {
251                 if (pm_idle_save)
252                         pm_idle_save();
253                 else
254                         acpi_safe_halt();
255                 return;
256         }
257
258         /*
259          * Check BM Activity
260          * -----------------
261          * Check for bus mastering activity (if required), record, and check
262          * for demotion.
263          */
264         if (pr->flags.bm_check) {
265                 u32 bm_status = 0;
266                 unsigned long diff = jiffies - pr->power.bm_check_timestamp;
267
268                 if (diff > 31)
269                         diff = 31;
270
271                 pr->power.bm_activity <<= diff;
272
273                 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
274                                   &bm_status, ACPI_MTX_DO_NOT_LOCK);
275                 if (bm_status) {
276                         pr->power.bm_activity |= 0x1;
277                         acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS,
278                                           1, ACPI_MTX_DO_NOT_LOCK);
279                 }
280                 /*
281                  * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
282                  * the true state of bus mastering activity; forcing us to
283                  * manually check the BMIDEA bit of each IDE channel.
284                  */
285                 else if (errata.piix4.bmisx) {
286                         if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
287                             || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
288                                 pr->power.bm_activity |= 0x1;
289                 }
290
291                 pr->power.bm_check_timestamp = jiffies;
292
293                 /*
294                  * If bus mastering is or was active this jiffy, demote
295                  * to avoid a faulty transition.  Note that the processor
296                  * won't enter a low-power state during this call (to this
297                  * function) but should upon the next.
298                  *
299                  * TBD: A better policy might be to fallback to the demotion
300                  *      state (use it for this quantum only) istead of
301                  *      demoting -- and rely on duration as our sole demotion
302                  *      qualification.  This may, however, introduce DMA
303                  *      issues (e.g. floppy DMA transfer overrun/underrun).
304                  */
305                 if ((pr->power.bm_activity & 0x1) &&
306                     cx->demotion.threshold.bm) {
307                         local_irq_enable();
308                         next_state = cx->demotion.state;
309                         goto end;
310                 }
311         }
312
313 #ifdef CONFIG_HOTPLUG_CPU
314         /*
315          * Check for P_LVL2_UP flag before entering C2 and above on
316          * an SMP system. We do it here instead of doing it at _CST/P_LVL
317          * detection phase, to work cleanly with logical CPU hotplug.
318          */
319         if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) && 
320             !pr->flags.has_cst && !acpi_fadt.plvl2_up)
321                 cx = &pr->power.states[ACPI_STATE_C1];
322 #endif
323
324         /*
325          * Sleep:
326          * ------
327          * Invoke the current Cx state to put the processor to sleep.
328          */
329         if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
330                 current_thread_info()->status &= ~TS_POLLING;
331                 smp_mb__after_clear_bit();
332                 if (need_resched()) {
333                         current_thread_info()->status |= TS_POLLING;
334                         local_irq_enable();
335                         return;
336                 }
337         }
338
339         switch (cx->type) {
340
341         case ACPI_STATE_C1:
342                 /*
343                  * Invoke C1.
344                  * Use the appropriate idle routine, the one that would
345                  * be used without acpi C-states.
346                  */
347                 if (pm_idle_save)
348                         pm_idle_save();
349                 else
350                         acpi_safe_halt();
351
352                 /*
353                  * TBD: Can't get time duration while in C1, as resumes
354                  *      go to an ISR rather than here.  Need to instrument
355                  *      base interrupt handler.
356                  */
357                 sleep_ticks = 0xFFFFFFFF;
358                 break;
359
360         case ACPI_STATE_C2:
361                 /* Get start time (ticks) */
362                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
363                 /* Invoke C2 */
364                 inb(cx->address);
365                 /* Dummy wait op - must do something useless after P_LVL2 read
366                    because chipsets cannot guarantee that STPCLK# signal
367                    gets asserted in time to freeze execution properly. */
368                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
369                 /* Get end time (ticks) */
370                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
371
372 #ifdef CONFIG_GENERIC_TIME
373                 /* TSC halts in C2, so notify users */
374                 mark_tsc_unstable();
375 #endif
376                 /* Re-enable interrupts */
377                 local_irq_enable();
378                 current_thread_info()->status |= TS_POLLING;
379                 /* Compute time (ticks) that we were actually asleep */
380                 sleep_ticks =
381                     ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
382                 break;
383
384         case ACPI_STATE_C3:
385
386                 if (pr->flags.bm_check) {
387                         if (atomic_inc_return(&c3_cpu_count) ==
388                             num_online_cpus()) {
389                                 /*
390                                  * All CPUs are trying to go to C3
391                                  * Disable bus master arbitration
392                                  */
393                                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1,
394                                                   ACPI_MTX_DO_NOT_LOCK);
395                         }
396                 } else {
397                         /* SMP with no shared cache... Invalidate cache  */
398                         ACPI_FLUSH_CPU_CACHE();
399                 }
400
401                 /* Get start time (ticks) */
402                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
403                 /* Invoke C3 */
404                 inb(cx->address);
405                 /* Dummy wait op (see above) */
406                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
407                 /* Get end time (ticks) */
408                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
409                 if (pr->flags.bm_check) {
410                         /* Enable bus master arbitration */
411                         atomic_dec(&c3_cpu_count);
412                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0,
413                                           ACPI_MTX_DO_NOT_LOCK);
414                 }
415
416 #ifdef CONFIG_GENERIC_TIME
417                 /* TSC halts in C3, so notify users */
418                 mark_tsc_unstable();
419 #endif
420                 /* Re-enable interrupts */
421                 local_irq_enable();
422                 current_thread_info()->status |= TS_POLLING;
423                 /* Compute time (ticks) that we were actually asleep */
424                 sleep_ticks =
425                     ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
426                 break;
427
428         default:
429                 local_irq_enable();
430                 return;
431         }
432         cx->usage++;
433         if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
434                 cx->time += sleep_ticks;
435
436         next_state = pr->power.state;
437
438 #ifdef CONFIG_HOTPLUG_CPU
439         /* Don't do promotion/demotion */
440         if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
441             !pr->flags.has_cst && !acpi_fadt.plvl2_up) {
442                 next_state = cx;
443                 goto end;
444         }
445 #endif
446
447         /*
448          * Promotion?
449          * ----------
450          * Track the number of longs (time asleep is greater than threshold)
451          * and promote when the count threshold is reached.  Note that bus
452          * mastering activity may prevent promotions.
453          * Do not promote above max_cstate.
454          */
455         if (cx->promotion.state &&
456             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
457                 if (sleep_ticks > cx->promotion.threshold.ticks &&
458                   cx->promotion.state->latency <= system_latency_constraint()) {
459                         cx->promotion.count++;
460                         cx->demotion.count = 0;
461                         if (cx->promotion.count >=
462                             cx->promotion.threshold.count) {
463                                 if (pr->flags.bm_check) {
464                                         if (!
465                                             (pr->power.bm_activity & cx->
466                                              promotion.threshold.bm)) {
467                                                 next_state =
468                                                     cx->promotion.state;
469                                                 goto end;
470                                         }
471                                 } else {
472                                         next_state = cx->promotion.state;
473                                         goto end;
474                                 }
475                         }
476                 }
477         }
478
479         /*
480          * Demotion?
481          * ---------
482          * Track the number of shorts (time asleep is less than time threshold)
483          * and demote when the usage threshold is reached.
484          */
485         if (cx->demotion.state) {
486                 if (sleep_ticks < cx->demotion.threshold.ticks) {
487                         cx->demotion.count++;
488                         cx->promotion.count = 0;
489                         if (cx->demotion.count >= cx->demotion.threshold.count) {
490                                 next_state = cx->demotion.state;
491                                 goto end;
492                         }
493                 }
494         }
495
496       end:
497         /*
498          * Demote if current state exceeds max_cstate
499          * or if the latency of the current state is unacceptable
500          */
501         if ((pr->power.state - pr->power.states) > max_cstate ||
502                 pr->power.state->latency > system_latency_constraint()) {
503                 if (cx->demotion.state)
504                         next_state = cx->demotion.state;
505         }
506
507         /*
508          * New Cx State?
509          * -------------
510          * If we're going to start using a new Cx state we must clean up
511          * from the previous and prepare to use the new.
512          */
513         if (next_state != pr->power.state)
514                 acpi_processor_power_activate(pr, next_state);
515 }
516
517 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
518 {
519         unsigned int i;
520         unsigned int state_is_set = 0;
521         struct acpi_processor_cx *lower = NULL;
522         struct acpi_processor_cx *higher = NULL;
523         struct acpi_processor_cx *cx;
524
525
526         if (!pr)
527                 return -EINVAL;
528
529         /*
530          * This function sets the default Cx state policy (OS idle handler).
531          * Our scheme is to promote quickly to C2 but more conservatively
532          * to C3.  We're favoring C2  for its characteristics of low latency
533          * (quick response), good power savings, and ability to allow bus
534          * mastering activity.  Note that the Cx state policy is completely
535          * customizable and can be altered dynamically.
536          */
537
538         /* startup state */
539         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
540                 cx = &pr->power.states[i];
541                 if (!cx->valid)
542                         continue;
543
544                 if (!state_is_set)
545                         pr->power.state = cx;
546                 state_is_set++;
547                 break;
548         }
549
550         if (!state_is_set)
551                 return -ENODEV;
552
553         /* demotion */
554         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
555                 cx = &pr->power.states[i];
556                 if (!cx->valid)
557                         continue;
558
559                 if (lower) {
560                         cx->demotion.state = lower;
561                         cx->demotion.threshold.ticks = cx->latency_ticks;
562                         cx->demotion.threshold.count = 1;
563                         if (cx->type == ACPI_STATE_C3)
564                                 cx->demotion.threshold.bm = bm_history;
565                 }
566
567                 lower = cx;
568         }
569
570         /* promotion */
571         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
572                 cx = &pr->power.states[i];
573                 if (!cx->valid)
574                         continue;
575
576                 if (higher) {
577                         cx->promotion.state = higher;
578                         cx->promotion.threshold.ticks = cx->latency_ticks;
579                         if (cx->type >= ACPI_STATE_C2)
580                                 cx->promotion.threshold.count = 4;
581                         else
582                                 cx->promotion.threshold.count = 10;
583                         if (higher->type == ACPI_STATE_C3)
584                                 cx->promotion.threshold.bm = bm_history;
585                 }
586
587                 higher = cx;
588         }
589
590         return 0;
591 }
592
593 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
594 {
595
596         if (!pr)
597                 return -EINVAL;
598
599         if (!pr->pblk)
600                 return -ENODEV;
601
602         /* if info is obtained from pblk/fadt, type equals state */
603         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
604         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
605
606 #ifndef CONFIG_HOTPLUG_CPU
607         /*
608          * Check for P_LVL2_UP flag before entering C2 and above on
609          * an SMP system. 
610          */
611         if ((num_online_cpus() > 1) && !acpi_fadt.plvl2_up)
612                 return -ENODEV;
613 #endif
614
615         /* determine C2 and C3 address from pblk */
616         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
617         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
618
619         /* determine latencies from FADT */
620         pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat;
621         pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;
622
623         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
624                           "lvl2[0x%08x] lvl3[0x%08x]\n",
625                           pr->power.states[ACPI_STATE_C2].address,
626                           pr->power.states[ACPI_STATE_C3].address));
627
628         return 0;
629 }
630
631 static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr)
632 {
633
634         /* Zero initialize all the C-states info. */
635         memset(pr->power.states, 0, sizeof(pr->power.states));
636
637         /* set the first C-State to C1 */
638         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
639
640         /* the C0 state only exists as a filler in our array,
641          * and all processors need to support C1 */
642         pr->power.states[ACPI_STATE_C0].valid = 1;
643         pr->power.states[ACPI_STATE_C1].valid = 1;
644
645         return 0;
646 }
647
648 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
649 {
650         acpi_status status = 0;
651         acpi_integer count;
652         int current_count;
653         int i;
654         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
655         union acpi_object *cst;
656
657
658         if (nocst)
659                 return -ENODEV;
660
661         current_count = 1;
662
663         /* Zero initialize C2 onwards and prepare for fresh CST lookup */
664         for (i = 2; i < ACPI_PROCESSOR_MAX_POWER; i++)
665                 memset(&(pr->power.states[i]), 0, 
666                                 sizeof(struct acpi_processor_cx));
667
668         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
669         if (ACPI_FAILURE(status)) {
670                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
671                 return -ENODEV;
672         }
673
674         cst = (union acpi_object *)buffer.pointer;
675
676         /* There must be at least 2 elements */
677         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
678                 printk(KERN_ERR PREFIX "not enough elements in _CST\n");
679                 status = -EFAULT;
680                 goto end;
681         }
682
683         count = cst->package.elements[0].integer.value;
684
685         /* Validate number of power states. */
686         if (count < 1 || count != cst->package.count - 1) {
687                 printk(KERN_ERR PREFIX "count given by _CST is not valid\n");
688                 status = -EFAULT;
689                 goto end;
690         }
691
692         /* Tell driver that at least _CST is supported. */
693         pr->flags.has_cst = 1;
694
695         for (i = 1; i <= count; i++) {
696                 union acpi_object *element;
697                 union acpi_object *obj;
698                 struct acpi_power_register *reg;
699                 struct acpi_processor_cx cx;
700
701                 memset(&cx, 0, sizeof(cx));
702
703                 element = (union acpi_object *)&(cst->package.elements[i]);
704                 if (element->type != ACPI_TYPE_PACKAGE)
705                         continue;
706
707                 if (element->package.count != 4)
708                         continue;
709
710                 obj = (union acpi_object *)&(element->package.elements[0]);
711
712                 if (obj->type != ACPI_TYPE_BUFFER)
713                         continue;
714
715                 reg = (struct acpi_power_register *)obj->buffer.pointer;
716
717                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
718                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
719                         continue;
720
721                 cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ?
722                     0 : reg->address;
723
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;
728
729                 cx.type = obj->integer.value;
730
731                 if ((cx.type != ACPI_STATE_C1) &&
732                     (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
733                         continue;
734
735                 if ((cx.type < ACPI_STATE_C2) || (cx.type > ACPI_STATE_C3))
736                         continue;
737
738                 obj = (union acpi_object *)&(element->package.elements[2]);
739                 if (obj->type != ACPI_TYPE_INTEGER)
740                         continue;
741
742                 cx.latency = obj->integer.value;
743
744                 obj = (union acpi_object *)&(element->package.elements[3]);
745                 if (obj->type != ACPI_TYPE_INTEGER)
746                         continue;
747
748                 cx.power = obj->integer.value;
749
750                 current_count++;
751                 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
752
753                 /*
754                  * We support total ACPI_PROCESSOR_MAX_POWER - 1
755                  * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
756                  */
757                 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
758                         printk(KERN_WARNING
759                                "Limiting number of power states to max (%d)\n",
760                                ACPI_PROCESSOR_MAX_POWER);
761                         printk(KERN_WARNING
762                                "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
763                         break;
764                 }
765         }
766
767         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
768                           current_count));
769
770         /* Validate number of power states discovered */
771         if (current_count < 2)
772                 status = -EFAULT;
773
774       end:
775         kfree(buffer.pointer);
776
777         return status;
778 }
779
780 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
781 {
782
783         if (!cx->address)
784                 return;
785
786         /*
787          * C2 latency must be less than or equal to 100
788          * microseconds.
789          */
790         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
791                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
792                                   "latency too large [%d]\n", cx->latency));
793                 return;
794         }
795
796         /*
797          * Otherwise we've met all of our C2 requirements.
798          * Normalize the C2 latency to expidite policy
799          */
800         cx->valid = 1;
801         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
802
803         return;
804 }
805
806 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
807                                            struct acpi_processor_cx *cx)
808 {
809         static int bm_check_flag;
810
811
812         if (!cx->address)
813                 return;
814
815         /*
816          * C3 latency must be less than or equal to 1000
817          * microseconds.
818          */
819         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
820                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
821                                   "latency too large [%d]\n", cx->latency));
822                 return;
823         }
824
825         /*
826          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
827          * DMA transfers are used by any ISA device to avoid livelock.
828          * Note that we could disable Type-F DMA (as recommended by
829          * the erratum), but this is known to disrupt certain ISA
830          * devices thus we take the conservative approach.
831          */
832         else if (errata.piix4.fdma) {
833                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
834                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
835                 return;
836         }
837
838         /* All the logic here assumes flags.bm_check is same across all CPUs */
839         if (!bm_check_flag) {
840                 /* Determine whether bm_check is needed based on CPU  */
841                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
842                 bm_check_flag = pr->flags.bm_check;
843         } else {
844                 pr->flags.bm_check = bm_check_flag;
845         }
846
847         if (pr->flags.bm_check) {
848                 /* bus mastering control is necessary */
849                 if (!pr->flags.bm_control) {
850                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
851                                           "C3 support requires bus mastering control\n"));
852                         return;
853                 }
854         } else {
855                 /*
856                  * WBINVD should be set in fadt, for C3 state to be
857                  * supported on when bm_check is not required.
858                  */
859                 if (acpi_fadt.wb_invd != 1) {
860                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
861                                           "Cache invalidation should work properly"
862                                           " for C3 to be enabled on SMP systems\n"));
863                         return;
864                 }
865                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD,
866                                   0, ACPI_MTX_DO_NOT_LOCK);
867         }
868
869         /*
870          * Otherwise we've met all of our C3 requirements.
871          * Normalize the C3 latency to expidite policy.  Enable
872          * checking of bus mastering status (bm_check) so we can
873          * use this in our C3 policy
874          */
875         cx->valid = 1;
876         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
877
878         return;
879 }
880
881 static int acpi_processor_power_verify(struct acpi_processor *pr)
882 {
883         unsigned int i;
884         unsigned int working = 0;
885
886 #ifdef ARCH_APICTIMER_STOPS_ON_C3
887         int timer_broadcast = 0;
888         cpumask_t mask = cpumask_of_cpu(pr->id);
889         on_each_cpu(switch_ipi_to_APIC_timer, &mask, 1, 1);
890 #endif
891
892         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
893                 struct acpi_processor_cx *cx = &pr->power.states[i];
894
895                 switch (cx->type) {
896                 case ACPI_STATE_C1:
897                         cx->valid = 1;
898                         break;
899
900                 case ACPI_STATE_C2:
901                         acpi_processor_power_verify_c2(cx);
902 #ifdef ARCH_APICTIMER_STOPS_ON_C3
903                         /* Some AMD systems fake C3 as C2, but still
904                            have timer troubles */
905                         if (cx->valid && 
906                                 boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
907                                 timer_broadcast++;
908 #endif
909                         break;
910
911                 case ACPI_STATE_C3:
912                         acpi_processor_power_verify_c3(pr, cx);
913 #ifdef ARCH_APICTIMER_STOPS_ON_C3
914                         if (cx->valid)
915                                 timer_broadcast++;
916 #endif
917                         break;
918                 }
919
920                 if (cx->valid)
921                         working++;
922         }
923
924 #ifdef ARCH_APICTIMER_STOPS_ON_C3
925         if (timer_broadcast)
926                 on_each_cpu(switch_APIC_timer_to_ipi, &mask, 1, 1);
927 #endif
928
929         return (working);
930 }
931
932 static int acpi_processor_get_power_info(struct acpi_processor *pr)
933 {
934         unsigned int i;
935         int result;
936
937
938         /* NOTE: the idle thread may not be running while calling
939          * this function */
940
941         /* Adding C1 state */
942         acpi_processor_get_power_info_default_c1(pr);
943         result = acpi_processor_get_power_info_cst(pr);
944         if (result == -ENODEV)
945                 acpi_processor_get_power_info_fadt(pr);
946
947         pr->power.count = acpi_processor_power_verify(pr);
948
949         /*
950          * Set Default Policy
951          * ------------------
952          * Now that we know which states are supported, set the default
953          * policy.  Note that this policy can be changed dynamically
954          * (e.g. encourage deeper sleeps to conserve battery life when
955          * not on AC).
956          */
957         result = acpi_processor_set_power_policy(pr);
958         if (result)
959                 return result;
960
961         /*
962          * if one state of type C2 or C3 is available, mark this
963          * CPU as being "idle manageable"
964          */
965         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
966                 if (pr->power.states[i].valid) {
967                         pr->power.count = i;
968                         if (pr->power.states[i].type >= ACPI_STATE_C2)
969                                 pr->flags.power = 1;
970                 }
971         }
972
973         return 0;
974 }
975
976 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
977 {
978         int result = 0;
979
980
981         if (!pr)
982                 return -EINVAL;
983
984         if (nocst) {
985                 return -ENODEV;
986         }
987
988         if (!pr->flags.power_setup_done)
989                 return -ENODEV;
990
991         /* Fall back to the default idle loop */
992         pm_idle = pm_idle_save;
993         synchronize_sched();    /* Relies on interrupts forcing exit from idle. */
994
995         pr->flags.power = 0;
996         result = acpi_processor_get_power_info(pr);
997         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
998                 pm_idle = acpi_processor_idle;
999
1000         return result;
1001 }
1002
1003 /* proc interface */
1004
1005 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
1006 {
1007         struct acpi_processor *pr = (struct acpi_processor *)seq->private;
1008         unsigned int i;
1009
1010
1011         if (!pr)
1012                 goto end;
1013
1014         seq_printf(seq, "active state:            C%zd\n"
1015                    "max_cstate:              C%d\n"
1016                    "bus master activity:     %08x\n"
1017                    "maximum allowed latency: %d usec\n",
1018                    pr->power.state ? pr->power.state - pr->power.states : 0,
1019                    max_cstate, (unsigned)pr->power.bm_activity,
1020                    system_latency_constraint());
1021
1022         seq_puts(seq, "states:\n");
1023
1024         for (i = 1; i <= pr->power.count; i++) {
1025                 seq_printf(seq, "   %cC%d:                  ",
1026                            (&pr->power.states[i] ==
1027                             pr->power.state ? '*' : ' '), i);
1028
1029                 if (!pr->power.states[i].valid) {
1030                         seq_puts(seq, "<not supported>\n");
1031                         continue;
1032                 }
1033
1034                 switch (pr->power.states[i].type) {
1035                 case ACPI_STATE_C1:
1036                         seq_printf(seq, "type[C1] ");
1037                         break;
1038                 case ACPI_STATE_C2:
1039                         seq_printf(seq, "type[C2] ");
1040                         break;
1041                 case ACPI_STATE_C3:
1042                         seq_printf(seq, "type[C3] ");
1043                         break;
1044                 default:
1045                         seq_printf(seq, "type[--] ");
1046                         break;
1047                 }
1048
1049                 if (pr->power.states[i].promotion.state)
1050                         seq_printf(seq, "promotion[C%zd] ",
1051                                    (pr->power.states[i].promotion.state -
1052                                     pr->power.states));
1053                 else
1054                         seq_puts(seq, "promotion[--] ");
1055
1056                 if (pr->power.states[i].demotion.state)
1057                         seq_printf(seq, "demotion[C%zd] ",
1058                                    (pr->power.states[i].demotion.state -
1059                                     pr->power.states));
1060                 else
1061                         seq_puts(seq, "demotion[--] ");
1062
1063                 seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n",
1064                            pr->power.states[i].latency,
1065                            pr->power.states[i].usage,
1066                            pr->power.states[i].time);
1067         }
1068
1069       end:
1070         return 0;
1071 }
1072
1073 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
1074 {
1075         return single_open(file, acpi_processor_power_seq_show,
1076                            PDE(inode)->data);
1077 }
1078
1079 static const struct file_operations acpi_processor_power_fops = {
1080         .open = acpi_processor_power_open_fs,
1081         .read = seq_read,
1082         .llseek = seq_lseek,
1083         .release = single_release,
1084 };
1085
1086 static void smp_callback(void *v)
1087 {
1088         /* we already woke the CPU up, nothing more to do */
1089 }
1090
1091 /*
1092  * This function gets called when a part of the kernel has a new latency
1093  * requirement.  This means we need to get all processors out of their C-state,
1094  * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
1095  * wakes them all right up.
1096  */
1097 static int acpi_processor_latency_notify(struct notifier_block *b,
1098                 unsigned long l, void *v)
1099 {
1100         smp_call_function(smp_callback, NULL, 0, 1);
1101         return NOTIFY_OK;
1102 }
1103
1104 static struct notifier_block acpi_processor_latency_notifier = {
1105         .notifier_call = acpi_processor_latency_notify,
1106 };
1107
1108 int acpi_processor_power_init(struct acpi_processor *pr,
1109                               struct acpi_device *device)
1110 {
1111         acpi_status status = 0;
1112         static int first_run;
1113         struct proc_dir_entry *entry = NULL;
1114         unsigned int i;
1115
1116
1117         if (!first_run) {
1118                 dmi_check_system(processor_power_dmi_table);
1119                 if (max_cstate < ACPI_C_STATES_MAX)
1120                         printk(KERN_NOTICE
1121                                "ACPI: processor limited to max C-state %d\n",
1122                                max_cstate);
1123                 first_run++;
1124                 register_latency_notifier(&acpi_processor_latency_notifier);
1125         }
1126
1127         if (!pr)
1128                 return -EINVAL;
1129
1130         if (acpi_fadt.cst_cnt && !nocst) {
1131                 status =
1132                     acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
1133                 if (ACPI_FAILURE(status)) {
1134                         ACPI_EXCEPTION((AE_INFO, status,
1135                                         "Notifying BIOS of _CST ability failed"));
1136                 }
1137         }
1138
1139         acpi_processor_get_power_info(pr);
1140
1141         /*
1142          * Install the idle handler if processor power management is supported.
1143          * Note that we use previously set idle handler will be used on
1144          * platforms that only support C1.
1145          */
1146         if ((pr->flags.power) && (!boot_option_idle_override)) {
1147                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1148                 for (i = 1; i <= pr->power.count; i++)
1149                         if (pr->power.states[i].valid)
1150                                 printk(" C%d[C%d]", i,
1151                                        pr->power.states[i].type);
1152                 printk(")\n");
1153
1154                 if (pr->id == 0) {
1155                         pm_idle_save = pm_idle;
1156                         pm_idle = acpi_processor_idle;
1157                 }
1158         }
1159
1160         /* 'power' [R] */
1161         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1162                                   S_IRUGO, acpi_device_dir(device));
1163         if (!entry)
1164                 return -EIO;
1165         else {
1166                 entry->proc_fops = &acpi_processor_power_fops;
1167                 entry->data = acpi_driver_data(device);
1168                 entry->owner = THIS_MODULE;
1169         }
1170
1171         pr->flags.power_setup_done = 1;
1172
1173         return 0;
1174 }
1175
1176 int acpi_processor_power_exit(struct acpi_processor *pr,
1177                               struct acpi_device *device)
1178 {
1179
1180         pr->flags.power_setup_done = 0;
1181
1182         if (acpi_device_dir(device))
1183                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1184                                   acpi_device_dir(device));
1185
1186         /* Unregister the idle handler when processor #0 is removed. */
1187         if (pr->id == 0) {
1188                 pm_idle = pm_idle_save;
1189
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();
1196                 unregister_latency_notifier(&acpi_processor_latency_notifier);
1197         }
1198
1199         return 0;
1200 }