Fix ACPI processor power block initialization
[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       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
42 #include <asm/io.h>
43 #include <asm/uaccess.h>
44
45 #include <acpi/acpi_bus.h>
46 #include <acpi/processor.h>
47
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);
58 module_param(max_cstate, uint, 0644);
59
60 static unsigned int nocst = 0;
61 module_param(nocst, uint, 0000);
62
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 =
71     (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
72 module_param(bm_history, uint, 0644);
73 /* --------------------------------------------------------------------------
74                                 Power Management
75    -------------------------------------------------------------------------- */
76
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;
87
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);
91
92         max_cstate = (long)id->driver_data;
93
94         return 0;
95 }
96
97 static struct dmi_system_id __initdata processor_power_dmi_table[] = {
98         {set_max_cstate, "IBM ThinkPad R40e", {
99                                                DMI_MATCH(DMI_BIOS_VENDOR,
100                                                          "IBM"),
101                                                DMI_MATCH(DMI_BIOS_VERSION,
102                                                          "1SET60WW")},
103          (void *)1},
104         {set_max_cstate, "Medion 41700", {
105                                           DMI_MATCH(DMI_BIOS_VENDOR,
106                                                     "Phoenix Technologies LTD"),
107                                           DMI_MATCH(DMI_BIOS_VERSION,
108                                                     "R01-A1J")}, (void *)1},
109         {set_max_cstate, "Clevo 5600D", {
110                                          DMI_MATCH(DMI_BIOS_VENDOR,
111                                                    "Phoenix Technologies LTD"),
112                                          DMI_MATCH(DMI_BIOS_VERSION,
113                                                    "SHE845M0.86C.0013.D.0302131307")},
114          (void *)2},
115         {},
116 };
117
118 static inline u32 ticks_elapsed(u32 t1, u32 t2)
119 {
120         if (t2 >= t1)
121                 return (t2 - t1);
122         else if (!acpi_fadt.tmr_val_ext)
123                 return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
124         else
125                 return ((0xFFFFFFFF - t1) + t2);
126 }
127
128 static void
129 acpi_processor_power_activate(struct acpi_processor *pr,
130                               struct acpi_processor_cx *new)
131 {
132         struct acpi_processor_cx *old;
133
134         if (!pr || !new)
135                 return;
136
137         old = pr->power.state;
138
139         if (old)
140                 old->promotion.count = 0;
141         new->demotion.count = 0;
142
143         /* Cleanup from old state. */
144         if (old) {
145                 switch (old->type) {
146                 case ACPI_STATE_C3:
147                         /* Disable bus master reload */
148                         if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
149                                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0,
150                                                   ACPI_MTX_DO_NOT_LOCK);
151                         break;
152                 }
153         }
154
155         /* Prepare to use new state. */
156         switch (new->type) {
157         case ACPI_STATE_C3:
158                 /* Enable bus master reload */
159                 if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
160                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1,
161                                           ACPI_MTX_DO_NOT_LOCK);
162                 break;
163         }
164
165         pr->power.state = new;
166
167         return;
168 }
169
170 static void acpi_safe_halt(void)
171 {
172         int polling = test_thread_flag(TIF_POLLING_NRFLAG);
173         if (polling) {
174                 clear_thread_flag(TIF_POLLING_NRFLAG);
175                 smp_mb__after_clear_bit();
176         }
177         if (!need_resched())
178                 safe_halt();
179         if (polling)
180                 set_thread_flag(TIF_POLLING_NRFLAG);
181 }
182
183 static atomic_t c3_cpu_count;
184
185 static void acpi_processor_idle(void)
186 {
187         struct acpi_processor *pr = NULL;
188         struct acpi_processor_cx *cx = NULL;
189         struct acpi_processor_cx *next_state = NULL;
190         int sleep_ticks = 0;
191         u32 t1, t2 = 0;
192
193         pr = processors[smp_processor_id()];
194         if (!pr)
195                 return;
196
197         /*
198          * Interrupts must be disabled during bus mastering calculations and
199          * for C2/C3 transitions.
200          */
201         local_irq_disable();
202
203         /*
204          * Check whether we truly need to go idle, or should
205          * reschedule:
206          */
207         if (unlikely(need_resched())) {
208                 local_irq_enable();
209                 return;
210         }
211
212         cx = pr->power.state;
213         if (!cx) {
214                 if (pm_idle_save)
215                         pm_idle_save();
216                 else
217                         acpi_safe_halt();
218                 return;
219         }
220
221         /*
222          * Check BM Activity
223          * -----------------
224          * Check for bus mastering activity (if required), record, and check
225          * for demotion.
226          */
227         if (pr->flags.bm_check) {
228                 u32 bm_status = 0;
229                 unsigned long diff = jiffies - pr->power.bm_check_timestamp;
230
231                 if (diff > 32)
232                         diff = 32;
233
234                 while (diff) {
235                         /* if we didn't get called, assume there was busmaster activity */
236                         diff--;
237                         if (diff)
238                                 pr->power.bm_activity |= 0x1;
239                         pr->power.bm_activity <<= 1;
240                 }
241
242                 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS,
243                                   &bm_status, ACPI_MTX_DO_NOT_LOCK);
244                 if (bm_status) {
245                         pr->power.bm_activity++;
246                         acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS,
247                                           1, ACPI_MTX_DO_NOT_LOCK);
248                 }
249                 /*
250                  * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
251                  * the true state of bus mastering activity; forcing us to
252                  * manually check the BMIDEA bit of each IDE channel.
253                  */
254                 else if (errata.piix4.bmisx) {
255                         if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
256                             || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
257                                 pr->power.bm_activity++;
258                 }
259
260                 pr->power.bm_check_timestamp = jiffies;
261
262                 /*
263                  * Apply bus mastering demotion policy.  Automatically demote
264                  * to avoid a faulty transition.  Note that the processor
265                  * won't enter a low-power state during this call (to this
266                  * funciton) but should upon the next.
267                  *
268                  * TBD: A better policy might be to fallback to the demotion
269                  *      state (use it for this quantum only) istead of
270                  *      demoting -- and rely on duration as our sole demotion
271                  *      qualification.  This may, however, introduce DMA
272                  *      issues (e.g. floppy DMA transfer overrun/underrun).
273                  */
274                 if (pr->power.bm_activity & cx->demotion.threshold.bm) {
275                         local_irq_enable();
276                         next_state = cx->demotion.state;
277                         goto end;
278                 }
279         }
280
281         cx->usage++;
282
283         /*
284          * Sleep:
285          * ------
286          * Invoke the current Cx state to put the processor to sleep.
287          */
288         switch (cx->type) {
289
290         case ACPI_STATE_C1:
291                 /*
292                  * Invoke C1.
293                  * Use the appropriate idle routine, the one that would
294                  * be used without acpi C-states.
295                  */
296                 if (pm_idle_save)
297                         pm_idle_save();
298                 else
299                         acpi_safe_halt();
300
301                 /*
302                  * TBD: Can't get time duration while in C1, as resumes
303                  *      go to an ISR rather than here.  Need to instrument
304                  *      base interrupt handler.
305                  */
306                 sleep_ticks = 0xFFFFFFFF;
307                 break;
308
309         case ACPI_STATE_C2:
310                 /* Get start time (ticks) */
311                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
312                 /* Invoke C2 */
313                 inb(cx->address);
314                 /* Dummy op - must do something useless after P_LVL2 read */
315                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
316                 /* Get end time (ticks) */
317                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
318                 /* Re-enable interrupts */
319                 local_irq_enable();
320                 /* Compute time (ticks) that we were actually asleep */
321                 sleep_ticks =
322                     ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
323                 break;
324
325         case ACPI_STATE_C3:
326
327                 if (pr->flags.bm_check) {
328                         if (atomic_inc_return(&c3_cpu_count) ==
329                             num_online_cpus()) {
330                                 /*
331                                  * All CPUs are trying to go to C3
332                                  * Disable bus master arbitration
333                                  */
334                                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1,
335                                                   ACPI_MTX_DO_NOT_LOCK);
336                         }
337                 } else {
338                         /* SMP with no shared cache... Invalidate cache  */
339                         ACPI_FLUSH_CPU_CACHE();
340                 }
341
342                 /* Get start time (ticks) */
343                 t1 = inl(acpi_fadt.xpm_tmr_blk.address);
344                 /* Invoke C3 */
345                 inb(cx->address);
346                 /* Dummy op - must do something useless after P_LVL3 read */
347                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
348                 /* Get end time (ticks) */
349                 t2 = inl(acpi_fadt.xpm_tmr_blk.address);
350                 if (pr->flags.bm_check) {
351                         /* Enable bus master arbitration */
352                         atomic_dec(&c3_cpu_count);
353                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0,
354                                           ACPI_MTX_DO_NOT_LOCK);
355                 }
356
357                 /* Re-enable interrupts */
358                 local_irq_enable();
359                 /* Compute time (ticks) that we were actually asleep */
360                 sleep_ticks =
361                     ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
362                 break;
363
364         default:
365                 local_irq_enable();
366                 return;
367         }
368
369         next_state = pr->power.state;
370
371         /*
372          * Promotion?
373          * ----------
374          * Track the number of longs (time asleep is greater than threshold)
375          * and promote when the count threshold is reached.  Note that bus
376          * mastering activity may prevent promotions.
377          * Do not promote above max_cstate.
378          */
379         if (cx->promotion.state &&
380             ((cx->promotion.state - pr->power.states) <= max_cstate)) {
381                 if (sleep_ticks > cx->promotion.threshold.ticks) {
382                         cx->promotion.count++;
383                         cx->demotion.count = 0;
384                         if (cx->promotion.count >=
385                             cx->promotion.threshold.count) {
386                                 if (pr->flags.bm_check) {
387                                         if (!
388                                             (pr->power.bm_activity & cx->
389                                              promotion.threshold.bm)) {
390                                                 next_state =
391                                                     cx->promotion.state;
392                                                 goto end;
393                                         }
394                                 } else {
395                                         next_state = cx->promotion.state;
396                                         goto end;
397                                 }
398                         }
399                 }
400         }
401
402         /*
403          * Demotion?
404          * ---------
405          * Track the number of shorts (time asleep is less than time threshold)
406          * and demote when the usage threshold is reached.
407          */
408         if (cx->demotion.state) {
409                 if (sleep_ticks < cx->demotion.threshold.ticks) {
410                         cx->demotion.count++;
411                         cx->promotion.count = 0;
412                         if (cx->demotion.count >= cx->demotion.threshold.count) {
413                                 next_state = cx->demotion.state;
414                                 goto end;
415                         }
416                 }
417         }
418
419       end:
420         /*
421          * Demote if current state exceeds max_cstate
422          */
423         if ((pr->power.state - pr->power.states) > max_cstate) {
424                 if (cx->demotion.state)
425                         next_state = cx->demotion.state;
426         }
427
428         /*
429          * New Cx State?
430          * -------------
431          * If we're going to start using a new Cx state we must clean up
432          * from the previous and prepare to use the new.
433          */
434         if (next_state != pr->power.state)
435                 acpi_processor_power_activate(pr, next_state);
436 }
437
438 static int acpi_processor_set_power_policy(struct acpi_processor *pr)
439 {
440         unsigned int i;
441         unsigned int state_is_set = 0;
442         struct acpi_processor_cx *lower = NULL;
443         struct acpi_processor_cx *higher = NULL;
444         struct acpi_processor_cx *cx;
445
446         ACPI_FUNCTION_TRACE("acpi_processor_set_power_policy");
447
448         if (!pr)
449                 return_VALUE(-EINVAL);
450
451         /*
452          * This function sets the default Cx state policy (OS idle handler).
453          * Our scheme is to promote quickly to C2 but more conservatively
454          * to C3.  We're favoring C2  for its characteristics of low latency
455          * (quick response), good power savings, and ability to allow bus
456          * mastering activity.  Note that the Cx state policy is completely
457          * customizable and can be altered dynamically.
458          */
459
460         /* startup state */
461         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
462                 cx = &pr->power.states[i];
463                 if (!cx->valid)
464                         continue;
465
466                 if (!state_is_set)
467                         pr->power.state = cx;
468                 state_is_set++;
469                 break;
470         }
471
472         if (!state_is_set)
473                 return_VALUE(-ENODEV);
474
475         /* demotion */
476         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
477                 cx = &pr->power.states[i];
478                 if (!cx->valid)
479                         continue;
480
481                 if (lower) {
482                         cx->demotion.state = lower;
483                         cx->demotion.threshold.ticks = cx->latency_ticks;
484                         cx->demotion.threshold.count = 1;
485                         if (cx->type == ACPI_STATE_C3)
486                                 cx->demotion.threshold.bm = bm_history;
487                 }
488
489                 lower = cx;
490         }
491
492         /* promotion */
493         for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
494                 cx = &pr->power.states[i];
495                 if (!cx->valid)
496                         continue;
497
498                 if (higher) {
499                         cx->promotion.state = higher;
500                         cx->promotion.threshold.ticks = cx->latency_ticks;
501                         if (cx->type >= ACPI_STATE_C2)
502                                 cx->promotion.threshold.count = 4;
503                         else
504                                 cx->promotion.threshold.count = 10;
505                         if (higher->type == ACPI_STATE_C3)
506                                 cx->promotion.threshold.bm = bm_history;
507                 }
508
509                 higher = cx;
510         }
511
512         return_VALUE(0);
513 }
514
515 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
516 {
517         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_fadt");
518
519         if (!pr)
520                 return_VALUE(-EINVAL);
521
522         if (!pr->pblk)
523                 return_VALUE(-ENODEV);
524
525         memset(pr->power.states, 0, sizeof(pr->power.states));
526
527         /* if info is obtained from pblk/fadt, type equals state */
528         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
529         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
530         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
531
532         /* the C0 state only exists as a filler in our array,
533          * and all processors need to support C1 */
534         pr->power.states[ACPI_STATE_C0].valid = 1;
535         pr->power.states[ACPI_STATE_C1].valid = 1;
536
537         /* determine C2 and C3 address from pblk */
538         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
539         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
540
541         /* determine latencies from FADT */
542         pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat;
543         pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;
544
545         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
546                           "lvl2[0x%08x] lvl3[0x%08x]\n",
547                           pr->power.states[ACPI_STATE_C2].address,
548                           pr->power.states[ACPI_STATE_C3].address));
549
550         return_VALUE(0);
551 }
552
553 static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr)
554 {
555         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_default_c1");
556
557         memset(pr->power.states, 0, sizeof(pr->power.states));
558
559         /* if info is obtained from pblk/fadt, type equals state */
560         pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
561         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
562         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
563
564         /* the C0 state only exists as a filler in our array,
565          * and all processors need to support C1 */
566         pr->power.states[ACPI_STATE_C0].valid = 1;
567         pr->power.states[ACPI_STATE_C1].valid = 1;
568
569         return_VALUE(0);
570 }
571
572 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
573 {
574         acpi_status status = 0;
575         acpi_integer count;
576         int i;
577         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
578         union acpi_object *cst;
579
580         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info_cst");
581
582         if (nocst)
583                 return_VALUE(-ENODEV);
584
585         pr->power.count = 0;
586         for (i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++)
587                 memset(&(pr->power.states[i]), 0,
588                        sizeof(struct acpi_processor_cx));
589
590         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
591         if (ACPI_FAILURE(status)) {
592                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
593                 return_VALUE(-ENODEV);
594         }
595
596         cst = (union acpi_object *)buffer.pointer;
597
598         /* There must be at least 2 elements */
599         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
600                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
601                                   "not enough elements in _CST\n"));
602                 status = -EFAULT;
603                 goto end;
604         }
605
606         count = cst->package.elements[0].integer.value;
607
608         /* Validate number of power states. */
609         if (count < 1 || count != cst->package.count - 1) {
610                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
611                                   "count given by _CST is not valid\n"));
612                 status = -EFAULT;
613                 goto end;
614         }
615
616         /* We support up to ACPI_PROCESSOR_MAX_POWER. */
617         if (count > ACPI_PROCESSOR_MAX_POWER) {
618                 printk(KERN_WARNING
619                        "Limiting number of power states to max (%d)\n",
620                        ACPI_PROCESSOR_MAX_POWER);
621                 printk(KERN_WARNING
622                        "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
623                 count = ACPI_PROCESSOR_MAX_POWER;
624         }
625
626         /* Tell driver that at least _CST is supported. */
627         pr->flags.has_cst = 1;
628
629         for (i = 1; i <= count; i++) {
630                 union acpi_object *element;
631                 union acpi_object *obj;
632                 struct acpi_power_register *reg;
633                 struct acpi_processor_cx cx;
634
635                 memset(&cx, 0, sizeof(cx));
636
637                 element = (union acpi_object *)&(cst->package.elements[i]);
638                 if (element->type != ACPI_TYPE_PACKAGE)
639                         continue;
640
641                 if (element->package.count != 4)
642                         continue;
643
644                 obj = (union acpi_object *)&(element->package.elements[0]);
645
646                 if (obj->type != ACPI_TYPE_BUFFER)
647                         continue;
648
649                 reg = (struct acpi_power_register *)obj->buffer.pointer;
650
651                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
652                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
653                         continue;
654
655                 cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ?
656                     0 : reg->address;
657
658                 /* There should be an easy way to extract an integer... */
659                 obj = (union acpi_object *)&(element->package.elements[1]);
660                 if (obj->type != ACPI_TYPE_INTEGER)
661                         continue;
662
663                 cx.type = obj->integer.value;
664
665                 if ((cx.type != ACPI_STATE_C1) &&
666                     (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO))
667                         continue;
668
669                 if ((cx.type < ACPI_STATE_C1) || (cx.type > ACPI_STATE_C3))
670                         continue;
671
672                 obj = (union acpi_object *)&(element->package.elements[2]);
673                 if (obj->type != ACPI_TYPE_INTEGER)
674                         continue;
675
676                 cx.latency = obj->integer.value;
677
678                 obj = (union acpi_object *)&(element->package.elements[3]);
679                 if (obj->type != ACPI_TYPE_INTEGER)
680                         continue;
681
682                 cx.power = obj->integer.value;
683
684                 (pr->power.count)++;
685                 memcpy(&(pr->power.states[pr->power.count]), &cx, sizeof(cx));
686         }
687
688         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
689                           pr->power.count));
690
691         /* Validate number of power states discovered */
692         if (pr->power.count < 2)
693                 status = -ENODEV;
694
695       end:
696         acpi_os_free(buffer.pointer);
697
698         return_VALUE(status);
699 }
700
701 static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
702 {
703         ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c2");
704
705         if (!cx->address)
706                 return_VOID;
707
708         /*
709          * C2 latency must be less than or equal to 100
710          * microseconds.
711          */
712         else if (cx->latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
713                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
714                                   "latency too large [%d]\n", cx->latency));
715                 return_VOID;
716         }
717
718         /*
719          * Otherwise we've met all of our C2 requirements.
720          * Normalize the C2 latency to expidite policy
721          */
722         cx->valid = 1;
723         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
724
725         return_VOID;
726 }
727
728 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
729                                            struct acpi_processor_cx *cx)
730 {
731         static int bm_check_flag;
732
733         ACPI_FUNCTION_TRACE("acpi_processor_get_power_verify_c3");
734
735         if (!cx->address)
736                 return_VOID;
737
738         /*
739          * C3 latency must be less than or equal to 1000
740          * microseconds.
741          */
742         else if (cx->latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
743                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
744                                   "latency too large [%d]\n", cx->latency));
745                 return_VOID;
746         }
747
748         /*
749          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
750          * DMA transfers are used by any ISA device to avoid livelock.
751          * Note that we could disable Type-F DMA (as recommended by
752          * the erratum), but this is known to disrupt certain ISA
753          * devices thus we take the conservative approach.
754          */
755         else if (errata.piix4.fdma) {
756                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
757                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
758                 return_VOID;
759         }
760
761         /* All the logic here assumes flags.bm_check is same across all CPUs */
762         if (!bm_check_flag) {
763                 /* Determine whether bm_check is needed based on CPU  */
764                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
765                 bm_check_flag = pr->flags.bm_check;
766         } else {
767                 pr->flags.bm_check = bm_check_flag;
768         }
769
770         if (pr->flags.bm_check) {
771                 /* bus mastering control is necessary */
772                 if (!pr->flags.bm_control) {
773                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
774                                           "C3 support requires bus mastering control\n"));
775                         return_VOID;
776                 }
777         } else {
778                 /*
779                  * WBINVD should be set in fadt, for C3 state to be
780                  * supported on when bm_check is not required.
781                  */
782                 if (acpi_fadt.wb_invd != 1) {
783                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
784                                           "Cache invalidation should work properly"
785                                           " for C3 to be enabled on SMP systems\n"));
786                         return_VOID;
787                 }
788                 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD,
789                                   0, ACPI_MTX_DO_NOT_LOCK);
790         }
791
792         /*
793          * Otherwise we've met all of our C3 requirements.
794          * Normalize the C3 latency to expidite policy.  Enable
795          * checking of bus mastering status (bm_check) so we can
796          * use this in our C3 policy
797          */
798         cx->valid = 1;
799         cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
800
801         return_VOID;
802 }
803
804 static int acpi_processor_power_verify(struct acpi_processor *pr)
805 {
806         unsigned int i;
807         unsigned int working = 0;
808
809         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
810                 struct acpi_processor_cx *cx = &pr->power.states[i];
811
812                 switch (cx->type) {
813                 case ACPI_STATE_C1:
814                         cx->valid = 1;
815                         break;
816
817                 case ACPI_STATE_C2:
818                         acpi_processor_power_verify_c2(cx);
819                         break;
820
821                 case ACPI_STATE_C3:
822                         acpi_processor_power_verify_c3(pr, cx);
823                         break;
824                 }
825
826                 if (cx->valid)
827                         working++;
828         }
829
830         return (working);
831 }
832
833 static int acpi_processor_get_power_info(struct acpi_processor *pr)
834 {
835         unsigned int i;
836         int result;
837
838         ACPI_FUNCTION_TRACE("acpi_processor_get_power_info");
839
840         /* NOTE: the idle thread may not be running while calling
841          * this function */
842
843         result = acpi_processor_get_power_info_cst(pr);
844         if ((result) || (acpi_processor_power_verify(pr) < 2)) {
845                 result = acpi_processor_get_power_info_fadt(pr);
846                 if ((result) || (acpi_processor_power_verify(pr) < 2))
847                         result = acpi_processor_get_power_info_default_c1(pr);
848         }
849
850         /*
851          * Set Default Policy
852          * ------------------
853          * Now that we know which states are supported, set the default
854          * policy.  Note that this policy can be changed dynamically
855          * (e.g. encourage deeper sleeps to conserve battery life when
856          * not on AC).
857          */
858         result = acpi_processor_set_power_policy(pr);
859         if (result)
860                 return_VALUE(result);
861
862         /*
863          * if one state of type C2 or C3 is available, mark this
864          * CPU as being "idle manageable"
865          */
866         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
867                 if (pr->power.states[i].valid) {
868                         pr->power.count = i;
869                         if (pr->power.states[i].type >= ACPI_STATE_C2)
870                                 pr->flags.power = 1;
871                 }
872         }
873
874         return_VALUE(0);
875 }
876
877 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
878 {
879         int result = 0;
880
881         ACPI_FUNCTION_TRACE("acpi_processor_cst_has_changed");
882
883         if (!pr)
884                 return_VALUE(-EINVAL);
885
886         if (nocst) {
887                 return_VALUE(-ENODEV);
888         }
889
890         if (!pr->flags.power_setup_done)
891                 return_VALUE(-ENODEV);
892
893         /* Fall back to the default idle loop */
894         pm_idle = pm_idle_save;
895         synchronize_sched();    /* Relies on interrupts forcing exit from idle. */
896
897         pr->flags.power = 0;
898         result = acpi_processor_get_power_info(pr);
899         if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
900                 pm_idle = acpi_processor_idle;
901
902         return_VALUE(result);
903 }
904
905 /* proc interface */
906
907 static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset)
908 {
909         struct acpi_processor *pr = (struct acpi_processor *)seq->private;
910         unsigned int i;
911
912         ACPI_FUNCTION_TRACE("acpi_processor_power_seq_show");
913
914         if (!pr)
915                 goto end;
916
917         seq_printf(seq, "active state:            C%zd\n"
918                    "max_cstate:              C%d\n"
919                    "bus master activity:     %08x\n",
920                    pr->power.state ? pr->power.state - pr->power.states : 0,
921                    max_cstate, (unsigned)pr->power.bm_activity);
922
923         seq_puts(seq, "states:\n");
924
925         for (i = 1; i <= pr->power.count; i++) {
926                 seq_printf(seq, "   %cC%d:                  ",
927                            (&pr->power.states[i] ==
928                             pr->power.state ? '*' : ' '), i);
929
930                 if (!pr->power.states[i].valid) {
931                         seq_puts(seq, "<not supported>\n");
932                         continue;
933                 }
934
935                 switch (pr->power.states[i].type) {
936                 case ACPI_STATE_C1:
937                         seq_printf(seq, "type[C1] ");
938                         break;
939                 case ACPI_STATE_C2:
940                         seq_printf(seq, "type[C2] ");
941                         break;
942                 case ACPI_STATE_C3:
943                         seq_printf(seq, "type[C3] ");
944                         break;
945                 default:
946                         seq_printf(seq, "type[--] ");
947                         break;
948                 }
949
950                 if (pr->power.states[i].promotion.state)
951                         seq_printf(seq, "promotion[C%zd] ",
952                                    (pr->power.states[i].promotion.state -
953                                     pr->power.states));
954                 else
955                         seq_puts(seq, "promotion[--] ");
956
957                 if (pr->power.states[i].demotion.state)
958                         seq_printf(seq, "demotion[C%zd] ",
959                                    (pr->power.states[i].demotion.state -
960                                     pr->power.states));
961                 else
962                         seq_puts(seq, "demotion[--] ");
963
964                 seq_printf(seq, "latency[%03d] usage[%08d]\n",
965                            pr->power.states[i].latency,
966                            pr->power.states[i].usage);
967         }
968
969       end:
970         return_VALUE(0);
971 }
972
973 static int acpi_processor_power_open_fs(struct inode *inode, struct file *file)
974 {
975         return single_open(file, acpi_processor_power_seq_show,
976                            PDE(inode)->data);
977 }
978
979 static struct file_operations acpi_processor_power_fops = {
980         .open = acpi_processor_power_open_fs,
981         .read = seq_read,
982         .llseek = seq_lseek,
983         .release = single_release,
984 };
985
986 int acpi_processor_power_init(struct acpi_processor *pr,
987                               struct acpi_device *device)
988 {
989         acpi_status status = 0;
990         static int first_run = 0;
991         struct proc_dir_entry *entry = NULL;
992         unsigned int i;
993
994         ACPI_FUNCTION_TRACE("acpi_processor_power_init");
995
996         if (!first_run) {
997                 dmi_check_system(processor_power_dmi_table);
998                 if (max_cstate < ACPI_C_STATES_MAX)
999                         printk(KERN_NOTICE
1000                                "ACPI: processor limited to max C-state %d\n",
1001                                max_cstate);
1002                 first_run++;
1003         }
1004
1005         if (!pr)
1006                 return_VALUE(-EINVAL);
1007
1008         if (acpi_fadt.cst_cnt && !nocst) {
1009                 status =
1010                     acpi_os_write_port(acpi_fadt.smi_cmd, acpi_fadt.cst_cnt, 8);
1011                 if (ACPI_FAILURE(status)) {
1012                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
1013                                           "Notifying BIOS of _CST ability failed\n"));
1014                 }
1015         }
1016
1017         acpi_processor_power_init_pdc(&(pr->power), pr->id);
1018         acpi_processor_set_pdc(pr, pr->power.pdc);
1019         acpi_processor_get_power_info(pr);
1020
1021         /*
1022          * Install the idle handler if processor power management is supported.
1023          * Note that we use previously set idle handler will be used on
1024          * platforms that only support C1.
1025          */
1026         if ((pr->flags.power) && (!boot_option_idle_override)) {
1027                 printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
1028                 for (i = 1; i <= pr->power.count; i++)
1029                         if (pr->power.states[i].valid)
1030                                 printk(" C%d[C%d]", i,
1031                                        pr->power.states[i].type);
1032                 printk(")\n");
1033
1034                 if (pr->id == 0) {
1035                         pm_idle_save = pm_idle;
1036                         pm_idle = acpi_processor_idle;
1037                 }
1038         }
1039
1040         /* 'power' [R] */
1041         entry = create_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1042                                   S_IRUGO, acpi_device_dir(device));
1043         if (!entry)
1044                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
1045                                   "Unable to create '%s' fs entry\n",
1046                                   ACPI_PROCESSOR_FILE_POWER));
1047         else {
1048                 entry->proc_fops = &acpi_processor_power_fops;
1049                 entry->data = acpi_driver_data(device);
1050                 entry->owner = THIS_MODULE;
1051         }
1052
1053         pr->flags.power_setup_done = 1;
1054
1055         return_VALUE(0);
1056 }
1057
1058 int acpi_processor_power_exit(struct acpi_processor *pr,
1059                               struct acpi_device *device)
1060 {
1061         ACPI_FUNCTION_TRACE("acpi_processor_power_exit");
1062
1063         pr->flags.power_setup_done = 0;
1064
1065         if (acpi_device_dir(device))
1066                 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
1067                                   acpi_device_dir(device));
1068
1069         /* Unregister the idle handler when processor #0 is removed. */
1070         if (pr->id == 0) {
1071                 pm_idle = pm_idle_save;
1072
1073                 /*
1074                  * We are about to unload the current idle thread pm callback
1075                  * (pm_idle), Wait for all processors to update cached/local
1076                  * copies of pm_idle before proceeding.
1077                  */
1078                 cpu_idle_wait();
1079         }
1080
1081         return_VALUE(0);
1082 }