2 * processor_idle - idle state submodule to the ACPI processor driver
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
12 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.
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.
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.
28 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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>
44 #include <asm/uaccess.h>
46 #include <acpi/acpi_bus.h>
47 #include <acpi/processor.h>
49 #define ACPI_PROCESSOR_COMPONENT 0x01000000
50 #define ACPI_PROCESSOR_CLASS "processor"
51 #define _COMPONENT ACPI_PROCESSOR_COMPONENT
52 ACPI_MODULE_NAME("processor_idle");
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);
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
70 static unsigned int bm_history __read_mostly
=
71 (HZ
>= 800 ? 0xFFFFFFFF : ((1U << (HZ
/ 25)) - 1));
72 module_param(bm_history
, uint
, 0644);
73 /* --------------------------------------------------------------------------
75 -------------------------------------------------------------------------- */
78 * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
79 * For now disable this. Probably a bug somewhere else.
81 * To skip this limit, boot/load with a large max_cstate limit.
83 static int set_max_cstate(struct dmi_system_id
*id
)
85 if (max_cstate
> ACPI_PROCESSOR_MAX_POWER
)
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
;
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")},
158 static inline u32
ticks_elapsed(u32 t1
, u32 t2
)
162 else if (!(acpi_gbl_FADT
.flags
& ACPI_FADT_32BIT_TIMER
))
163 return (((0x00FFFFFF - t1
) + t2
) & 0x00FFFFFF);
165 return ((0xFFFFFFFF - t1
) + t2
);
169 acpi_processor_power_activate(struct acpi_processor
*pr
,
170 struct acpi_processor_cx
*new)
172 struct acpi_processor_cx
*old
;
177 old
= pr
->power
.state
;
180 old
->promotion
.count
= 0;
181 new->demotion
.count
= 0;
183 /* Cleanup from old state. */
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);
194 /* Prepare to use new state. */
197 /* Enable bus master reload */
198 if (old
->type
!= ACPI_STATE_C3
&& pr
->flags
.bm_check
)
199 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD
, 1);
203 pr
->power
.state
= new;
208 static void acpi_safe_halt(void)
210 current_thread_info()->status
&= ~TS_POLLING
;
212 * TS_POLLING-cleared state must be visible before we
218 current_thread_info()->status
|= TS_POLLING
;
221 static atomic_t c3_cpu_count
;
223 /* Common C-state entry for C2, C3, .. */
224 static void acpi_cstate_enter(struct acpi_processor_cx
*cstate
)
226 if (cstate
->space_id
== ACPI_CSTATE_FFH
) {
227 /* Call into architectural FFH based C-state */
228 acpi_processor_ffh_cstate_enter(cstate
);
231 /* IO port based C-state */
232 inb(cstate
->address
);
233 /* Dummy wait op - must do something useless after P_LVL2 read
234 because chipsets cannot guarantee that STPCLK# signal
235 gets asserted in time to freeze execution properly. */
236 unused
= inl(acpi_gbl_FADT
.xpm_timer_block
.address
);
240 static void acpi_processor_idle(void)
242 struct acpi_processor
*pr
= NULL
;
243 struct acpi_processor_cx
*cx
= NULL
;
244 struct acpi_processor_cx
*next_state
= NULL
;
248 pr
= processors
[smp_processor_id()];
253 * Interrupts must be disabled during bus mastering calculations and
254 * for C2/C3 transitions.
259 * Check whether we truly need to go idle, or should
262 if (unlikely(need_resched())) {
267 cx
= pr
->power
.state
;
279 * Check for bus mastering activity (if required), record, and check
282 if (pr
->flags
.bm_check
) {
284 unsigned long diff
= jiffies
- pr
->power
.bm_check_timestamp
;
289 pr
->power
.bm_activity
<<= diff
;
291 acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS
, &bm_status
);
293 pr
->power
.bm_activity
|= 0x1;
294 acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS
, 1);
297 * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
298 * the true state of bus mastering activity; forcing us to
299 * manually check the BMIDEA bit of each IDE channel.
301 else if (errata
.piix4
.bmisx
) {
302 if ((inb_p(errata
.piix4
.bmisx
+ 0x02) & 0x01)
303 || (inb_p(errata
.piix4
.bmisx
+ 0x0A) & 0x01))
304 pr
->power
.bm_activity
|= 0x1;
307 pr
->power
.bm_check_timestamp
= jiffies
;
310 * If bus mastering is or was active this jiffy, demote
311 * to avoid a faulty transition. Note that the processor
312 * won't enter a low-power state during this call (to this
313 * function) but should upon the next.
315 * TBD: A better policy might be to fallback to the demotion
316 * state (use it for this quantum only) istead of
317 * demoting -- and rely on duration as our sole demotion
318 * qualification. This may, however, introduce DMA
319 * issues (e.g. floppy DMA transfer overrun/underrun).
321 if ((pr
->power
.bm_activity
& 0x1) &&
322 cx
->demotion
.threshold
.bm
) {
324 next_state
= cx
->demotion
.state
;
329 #ifdef CONFIG_HOTPLUG_CPU
331 * Check for P_LVL2_UP flag before entering C2 and above on
332 * an SMP system. We do it here instead of doing it at _CST/P_LVL
333 * detection phase, to work cleanly with logical CPU hotplug.
335 if ((cx
->type
!= ACPI_STATE_C1
) && (num_online_cpus() > 1) &&
336 !pr
->flags
.has_cst
&& !(acpi_gbl_FADT
.flags
& ACPI_FADT_C2_MP_SUPPORTED
))
337 cx
= &pr
->power
.states
[ACPI_STATE_C1
];
343 * Invoke the current Cx state to put the processor to sleep.
345 if (cx
->type
== ACPI_STATE_C2
|| cx
->type
== ACPI_STATE_C3
) {
346 current_thread_info()->status
&= ~TS_POLLING
;
348 * TS_POLLING-cleared state must be visible before we
352 if (need_resched()) {
353 current_thread_info()->status
|= TS_POLLING
;
364 * Use the appropriate idle routine, the one that would
365 * be used without acpi C-states.
373 * TBD: Can't get time duration while in C1, as resumes
374 * go to an ISR rather than here. Need to instrument
375 * base interrupt handler.
377 sleep_ticks
= 0xFFFFFFFF;
381 /* Get start time (ticks) */
382 t1
= inl(acpi_gbl_FADT
.xpm_timer_block
.address
);
384 acpi_cstate_enter(cx
);
385 /* Get end time (ticks) */
386 t2
= inl(acpi_gbl_FADT
.xpm_timer_block
.address
);
388 #ifdef CONFIG_GENERIC_TIME
389 /* TSC halts in C2, so notify users */
392 /* Re-enable interrupts */
394 current_thread_info()->status
|= TS_POLLING
;
395 /* Compute time (ticks) that we were actually asleep */
397 ticks_elapsed(t1
, t2
) - cx
->latency_ticks
- C2_OVERHEAD
;
402 if (pr
->flags
.bm_check
) {
403 if (atomic_inc_return(&c3_cpu_count
) ==
406 * All CPUs are trying to go to C3
407 * Disable bus master arbitration
409 acpi_set_register(ACPI_BITREG_ARB_DISABLE
, 1);
412 /* SMP with no shared cache... Invalidate cache */
413 ACPI_FLUSH_CPU_CACHE();
416 /* Get start time (ticks) */
417 t1
= inl(acpi_gbl_FADT
.xpm_timer_block
.address
);
419 acpi_cstate_enter(cx
);
420 /* Get end time (ticks) */
421 t2
= inl(acpi_gbl_FADT
.xpm_timer_block
.address
);
422 if (pr
->flags
.bm_check
) {
423 /* Enable bus master arbitration */
424 atomic_dec(&c3_cpu_count
);
425 acpi_set_register(ACPI_BITREG_ARB_DISABLE
, 0);
428 #ifdef CONFIG_GENERIC_TIME
429 /* TSC halts in C3, so notify users */
432 /* Re-enable interrupts */
434 current_thread_info()->status
|= TS_POLLING
;
435 /* Compute time (ticks) that we were actually asleep */
437 ticks_elapsed(t1
, t2
) - cx
->latency_ticks
- C3_OVERHEAD
;
445 if ((cx
->type
!= ACPI_STATE_C1
) && (sleep_ticks
> 0))
446 cx
->time
+= sleep_ticks
;
448 next_state
= pr
->power
.state
;
450 #ifdef CONFIG_HOTPLUG_CPU
451 /* Don't do promotion/demotion */
452 if ((cx
->type
== ACPI_STATE_C1
) && (num_online_cpus() > 1) &&
453 !pr
->flags
.has_cst
&& !(acpi_gbl_FADT
.flags
& ACPI_FADT_C2_MP_SUPPORTED
)) {
462 * Track the number of longs (time asleep is greater than threshold)
463 * and promote when the count threshold is reached. Note that bus
464 * mastering activity may prevent promotions.
465 * Do not promote above max_cstate.
467 if (cx
->promotion
.state
&&
468 ((cx
->promotion
.state
- pr
->power
.states
) <= max_cstate
)) {
469 if (sleep_ticks
> cx
->promotion
.threshold
.ticks
&&
470 cx
->promotion
.state
->latency
<= system_latency_constraint()) {
471 cx
->promotion
.count
++;
472 cx
->demotion
.count
= 0;
473 if (cx
->promotion
.count
>=
474 cx
->promotion
.threshold
.count
) {
475 if (pr
->flags
.bm_check
) {
477 (pr
->power
.bm_activity
& cx
->
478 promotion
.threshold
.bm
)) {
484 next_state
= cx
->promotion
.state
;
494 * Track the number of shorts (time asleep is less than time threshold)
495 * and demote when the usage threshold is reached.
497 if (cx
->demotion
.state
) {
498 if (sleep_ticks
< cx
->demotion
.threshold
.ticks
) {
499 cx
->demotion
.count
++;
500 cx
->promotion
.count
= 0;
501 if (cx
->demotion
.count
>= cx
->demotion
.threshold
.count
) {
502 next_state
= cx
->demotion
.state
;
510 * Demote if current state exceeds max_cstate
511 * or if the latency of the current state is unacceptable
513 if ((pr
->power
.state
- pr
->power
.states
) > max_cstate
||
514 pr
->power
.state
->latency
> system_latency_constraint()) {
515 if (cx
->demotion
.state
)
516 next_state
= cx
->demotion
.state
;
522 * If we're going to start using a new Cx state we must clean up
523 * from the previous and prepare to use the new.
525 if (next_state
!= pr
->power
.state
)
526 acpi_processor_power_activate(pr
, next_state
);
529 static int acpi_processor_set_power_policy(struct acpi_processor
*pr
)
532 unsigned int state_is_set
= 0;
533 struct acpi_processor_cx
*lower
= NULL
;
534 struct acpi_processor_cx
*higher
= NULL
;
535 struct acpi_processor_cx
*cx
;
542 * This function sets the default Cx state policy (OS idle handler).
543 * Our scheme is to promote quickly to C2 but more conservatively
544 * to C3. We're favoring C2 for its characteristics of low latency
545 * (quick response), good power savings, and ability to allow bus
546 * mastering activity. Note that the Cx state policy is completely
547 * customizable and can be altered dynamically.
551 for (i
= 1; i
< ACPI_PROCESSOR_MAX_POWER
; i
++) {
552 cx
= &pr
->power
.states
[i
];
557 pr
->power
.state
= cx
;
566 for (i
= 1; i
< ACPI_PROCESSOR_MAX_POWER
; i
++) {
567 cx
= &pr
->power
.states
[i
];
572 cx
->demotion
.state
= lower
;
573 cx
->demotion
.threshold
.ticks
= cx
->latency_ticks
;
574 cx
->demotion
.threshold
.count
= 1;
575 if (cx
->type
== ACPI_STATE_C3
)
576 cx
->demotion
.threshold
.bm
= bm_history
;
583 for (i
= (ACPI_PROCESSOR_MAX_POWER
- 1); i
> 0; i
--) {
584 cx
= &pr
->power
.states
[i
];
589 cx
->promotion
.state
= higher
;
590 cx
->promotion
.threshold
.ticks
= cx
->latency_ticks
;
591 if (cx
->type
>= ACPI_STATE_C2
)
592 cx
->promotion
.threshold
.count
= 4;
594 cx
->promotion
.threshold
.count
= 10;
595 if (higher
->type
== ACPI_STATE_C3
)
596 cx
->promotion
.threshold
.bm
= bm_history
;
605 static int acpi_processor_get_power_info_fadt(struct acpi_processor
*pr
)
614 /* if info is obtained from pblk/fadt, type equals state */
615 pr
->power
.states
[ACPI_STATE_C2
].type
= ACPI_STATE_C2
;
616 pr
->power
.states
[ACPI_STATE_C3
].type
= ACPI_STATE_C3
;
618 #ifndef CONFIG_HOTPLUG_CPU
620 * Check for P_LVL2_UP flag before entering C2 and above on
623 if ((num_online_cpus() > 1) &&
624 !(acpi_gbl_FADT
.flags
& ACPI_FADT_C2_MP_SUPPORTED
))
628 /* determine C2 and C3 address from pblk */
629 pr
->power
.states
[ACPI_STATE_C2
].address
= pr
->pblk
+ 4;
630 pr
->power
.states
[ACPI_STATE_C3
].address
= pr
->pblk
+ 5;
632 /* determine latencies from FADT */
633 pr
->power
.states
[ACPI_STATE_C2
].latency
= acpi_gbl_FADT
.C2latency
;
634 pr
->power
.states
[ACPI_STATE_C3
].latency
= acpi_gbl_FADT
.C3latency
;
636 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
637 "lvl2[0x%08x] lvl3[0x%08x]\n",
638 pr
->power
.states
[ACPI_STATE_C2
].address
,
639 pr
->power
.states
[ACPI_STATE_C3
].address
));
644 static int acpi_processor_get_power_info_default(struct acpi_processor
*pr
)
646 if (!pr
->power
.states
[ACPI_STATE_C1
].valid
) {
647 /* set the first C-State to C1 */
648 /* all processors need to support C1 */
649 pr
->power
.states
[ACPI_STATE_C1
].type
= ACPI_STATE_C1
;
650 pr
->power
.states
[ACPI_STATE_C1
].valid
= 1;
652 /* the C0 state only exists as a filler in our array */
653 pr
->power
.states
[ACPI_STATE_C0
].valid
= 1;
657 static int acpi_processor_get_power_info_cst(struct acpi_processor
*pr
)
659 acpi_status status
= 0;
663 struct acpi_buffer buffer
= { ACPI_ALLOCATE_BUFFER
, NULL
};
664 union acpi_object
*cst
;
672 status
= acpi_evaluate_object(pr
->handle
, "_CST", NULL
, &buffer
);
673 if (ACPI_FAILURE(status
)) {
674 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "No _CST, giving up\n"));
678 cst
= buffer
.pointer
;
680 /* There must be at least 2 elements */
681 if (!cst
|| (cst
->type
!= ACPI_TYPE_PACKAGE
) || cst
->package
.count
< 2) {
682 printk(KERN_ERR PREFIX
"not enough elements in _CST\n");
687 count
= cst
->package
.elements
[0].integer
.value
;
689 /* Validate number of power states. */
690 if (count
< 1 || count
!= cst
->package
.count
- 1) {
691 printk(KERN_ERR PREFIX
"count given by _CST is not valid\n");
696 /* Tell driver that at least _CST is supported. */
697 pr
->flags
.has_cst
= 1;
699 for (i
= 1; i
<= count
; i
++) {
700 union acpi_object
*element
;
701 union acpi_object
*obj
;
702 struct acpi_power_register
*reg
;
703 struct acpi_processor_cx cx
;
705 memset(&cx
, 0, sizeof(cx
));
707 element
= &(cst
->package
.elements
[i
]);
708 if (element
->type
!= ACPI_TYPE_PACKAGE
)
711 if (element
->package
.count
!= 4)
714 obj
= &(element
->package
.elements
[0]);
716 if (obj
->type
!= ACPI_TYPE_BUFFER
)
719 reg
= (struct acpi_power_register
*)obj
->buffer
.pointer
;
721 if (reg
->space_id
!= ACPI_ADR_SPACE_SYSTEM_IO
&&
722 (reg
->space_id
!= ACPI_ADR_SPACE_FIXED_HARDWARE
))
725 /* There should be an easy way to extract an integer... */
726 obj
= &(element
->package
.elements
[1]);
727 if (obj
->type
!= ACPI_TYPE_INTEGER
)
730 cx
.type
= obj
->integer
.value
;
732 * Some buggy BIOSes won't list C1 in _CST -
733 * Let acpi_processor_get_power_info_default() handle them later
735 if (i
== 1 && cx
.type
!= ACPI_STATE_C1
)
738 cx
.address
= reg
->address
;
739 cx
.index
= current_count
+ 1;
741 cx
.space_id
= ACPI_CSTATE_SYSTEMIO
;
742 if (reg
->space_id
== ACPI_ADR_SPACE_FIXED_HARDWARE
) {
743 if (acpi_processor_ffh_cstate_probe
744 (pr
->id
, &cx
, reg
) == 0) {
745 cx
.space_id
= ACPI_CSTATE_FFH
;
746 } else if (cx
.type
!= ACPI_STATE_C1
) {
748 * C1 is a special case where FIXED_HARDWARE
749 * can be handled in non-MWAIT way as well.
750 * In that case, save this _CST entry info.
751 * That is, we retain space_id of SYSTEM_IO for
753 * Otherwise, ignore this info and continue.
759 obj
= &(element
->package
.elements
[2]);
760 if (obj
->type
!= ACPI_TYPE_INTEGER
)
763 cx
.latency
= obj
->integer
.value
;
765 obj
= &(element
->package
.elements
[3]);
766 if (obj
->type
!= ACPI_TYPE_INTEGER
)
769 cx
.power
= obj
->integer
.value
;
772 memcpy(&(pr
->power
.states
[current_count
]), &cx
, sizeof(cx
));
775 * We support total ACPI_PROCESSOR_MAX_POWER - 1
776 * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
778 if (current_count
>= (ACPI_PROCESSOR_MAX_POWER
- 1)) {
780 "Limiting number of power states to max (%d)\n",
781 ACPI_PROCESSOR_MAX_POWER
);
783 "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
788 ACPI_DEBUG_PRINT((ACPI_DB_INFO
, "Found %d power states\n",
791 /* Validate number of power states discovered */
792 if (current_count
< 2)
796 kfree(buffer
.pointer
);
801 static void acpi_processor_power_verify_c2(struct acpi_processor_cx
*cx
)
808 * C2 latency must be less than or equal to 100
811 else if (cx
->latency
> ACPI_PROCESSOR_MAX_C2_LATENCY
) {
812 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
813 "latency too large [%d]\n", cx
->latency
));
818 * Otherwise we've met all of our C2 requirements.
819 * Normalize the C2 latency to expidite policy
822 cx
->latency_ticks
= US_TO_PM_TIMER_TICKS(cx
->latency
);
827 static void acpi_processor_power_verify_c3(struct acpi_processor
*pr
,
828 struct acpi_processor_cx
*cx
)
830 static int bm_check_flag
;
837 * C3 latency must be less than or equal to 1000
840 else if (cx
->latency
> ACPI_PROCESSOR_MAX_C3_LATENCY
) {
841 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
842 "latency too large [%d]\n", cx
->latency
));
847 * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
848 * DMA transfers are used by any ISA device to avoid livelock.
849 * Note that we could disable Type-F DMA (as recommended by
850 * the erratum), but this is known to disrupt certain ISA
851 * devices thus we take the conservative approach.
853 else if (errata
.piix4
.fdma
) {
854 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
855 "C3 not supported on PIIX4 with Type-F DMA\n"));
859 /* All the logic here assumes flags.bm_check is same across all CPUs */
860 if (!bm_check_flag
) {
861 /* Determine whether bm_check is needed based on CPU */
862 acpi_processor_power_init_bm_check(&(pr
->flags
), pr
->id
);
863 bm_check_flag
= pr
->flags
.bm_check
;
865 pr
->flags
.bm_check
= bm_check_flag
;
868 if (pr
->flags
.bm_check
) {
869 /* bus mastering control is necessary */
870 if (!pr
->flags
.bm_control
) {
871 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
872 "C3 support requires bus mastering control\n"));
877 * WBINVD should be set in fadt, for C3 state to be
878 * supported on when bm_check is not required.
880 if (!(acpi_gbl_FADT
.flags
& ACPI_FADT_WBINVD
)) {
881 ACPI_DEBUG_PRINT((ACPI_DB_INFO
,
882 "Cache invalidation should work properly"
883 " for C3 to be enabled on SMP systems\n"));
886 acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD
, 0);
890 * Otherwise we've met all of our C3 requirements.
891 * Normalize the C3 latency to expidite policy. Enable
892 * checking of bus mastering status (bm_check) so we can
893 * use this in our C3 policy
896 cx
->latency_ticks
= US_TO_PM_TIMER_TICKS(cx
->latency
);
901 static int acpi_processor_power_verify(struct acpi_processor
*pr
)
904 unsigned int working
= 0;
906 #ifdef ARCH_APICTIMER_STOPS_ON_C3
907 int timer_broadcast
= 0;
908 cpumask_t mask
= cpumask_of_cpu(pr
->id
);
909 on_each_cpu(switch_ipi_to_APIC_timer
, &mask
, 1, 1);
912 for (i
= 1; i
< ACPI_PROCESSOR_MAX_POWER
; i
++) {
913 struct acpi_processor_cx
*cx
= &pr
->power
.states
[i
];
921 acpi_processor_power_verify_c2(cx
);
922 #ifdef ARCH_APICTIMER_STOPS_ON_C3
923 /* Some AMD systems fake C3 as C2, but still
924 have timer troubles */
926 boot_cpu_data
.x86_vendor
== X86_VENDOR_AMD
)
932 acpi_processor_power_verify_c3(pr
, cx
);
933 #ifdef ARCH_APICTIMER_STOPS_ON_C3
944 #ifdef ARCH_APICTIMER_STOPS_ON_C3
946 on_each_cpu(switch_APIC_timer_to_ipi
, &mask
, 1, 1);
952 static int acpi_processor_get_power_info(struct acpi_processor
*pr
)
958 /* NOTE: the idle thread may not be running while calling
961 /* Zero initialize all the C-states info. */
962 memset(pr
->power
.states
, 0, sizeof(pr
->power
.states
));
964 result
= acpi_processor_get_power_info_cst(pr
);
965 if (result
== -ENODEV
)
966 result
= acpi_processor_get_power_info_fadt(pr
);
971 acpi_processor_get_power_info_default(pr
);
973 pr
->power
.count
= acpi_processor_power_verify(pr
);
978 * Now that we know which states are supported, set the default
979 * policy. Note that this policy can be changed dynamically
980 * (e.g. encourage deeper sleeps to conserve battery life when
983 result
= acpi_processor_set_power_policy(pr
);
988 * if one state of type C2 or C3 is available, mark this
989 * CPU as being "idle manageable"
991 for (i
= 1; i
< ACPI_PROCESSOR_MAX_POWER
; i
++) {
992 if (pr
->power
.states
[i
].valid
) {
994 if (pr
->power
.states
[i
].type
>= ACPI_STATE_C2
)
1002 int acpi_processor_cst_has_changed(struct acpi_processor
*pr
)
1014 if (!pr
->flags
.power_setup_done
)
1017 /* Fall back to the default idle loop */
1018 pm_idle
= pm_idle_save
;
1019 synchronize_sched(); /* Relies on interrupts forcing exit from idle. */
1021 pr
->flags
.power
= 0;
1022 result
= acpi_processor_get_power_info(pr
);
1023 if ((pr
->flags
.power
== 1) && (pr
->flags
.power_setup_done
))
1024 pm_idle
= acpi_processor_idle
;
1029 /* proc interface */
1031 static int acpi_processor_power_seq_show(struct seq_file
*seq
, void *offset
)
1033 struct acpi_processor
*pr
= seq
->private;
1040 seq_printf(seq
, "active state: C%zd\n"
1042 "bus master activity: %08x\n"
1043 "maximum allowed latency: %d usec\n",
1044 pr
->power
.state
? pr
->power
.state
- pr
->power
.states
: 0,
1045 max_cstate
, (unsigned)pr
->power
.bm_activity
,
1046 system_latency_constraint());
1048 seq_puts(seq
, "states:\n");
1050 for (i
= 1; i
<= pr
->power
.count
; i
++) {
1051 seq_printf(seq
, " %cC%d: ",
1052 (&pr
->power
.states
[i
] ==
1053 pr
->power
.state
? '*' : ' '), i
);
1055 if (!pr
->power
.states
[i
].valid
) {
1056 seq_puts(seq
, "<not supported>\n");
1060 switch (pr
->power
.states
[i
].type
) {
1062 seq_printf(seq
, "type[C1] ");
1065 seq_printf(seq
, "type[C2] ");
1068 seq_printf(seq
, "type[C3] ");
1071 seq_printf(seq
, "type[--] ");
1075 if (pr
->power
.states
[i
].promotion
.state
)
1076 seq_printf(seq
, "promotion[C%zd] ",
1077 (pr
->power
.states
[i
].promotion
.state
-
1080 seq_puts(seq
, "promotion[--] ");
1082 if (pr
->power
.states
[i
].demotion
.state
)
1083 seq_printf(seq
, "demotion[C%zd] ",
1084 (pr
->power
.states
[i
].demotion
.state
-
1087 seq_puts(seq
, "demotion[--] ");
1089 seq_printf(seq
, "latency[%03d] usage[%08d] duration[%020llu]\n",
1090 pr
->power
.states
[i
].latency
,
1091 pr
->power
.states
[i
].usage
,
1092 (unsigned long long)pr
->power
.states
[i
].time
);
1099 static int acpi_processor_power_open_fs(struct inode
*inode
, struct file
*file
)
1101 return single_open(file
, acpi_processor_power_seq_show
,
1105 static const struct file_operations acpi_processor_power_fops
= {
1106 .open
= acpi_processor_power_open_fs
,
1108 .llseek
= seq_lseek
,
1109 .release
= single_release
,
1113 static void smp_callback(void *v
)
1115 /* we already woke the CPU up, nothing more to do */
1119 * This function gets called when a part of the kernel has a new latency
1120 * requirement. This means we need to get all processors out of their C-state,
1121 * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
1122 * wakes them all right up.
1124 static int acpi_processor_latency_notify(struct notifier_block
*b
,
1125 unsigned long l
, void *v
)
1127 smp_call_function(smp_callback
, NULL
, 0, 1);
1131 static struct notifier_block acpi_processor_latency_notifier
= {
1132 .notifier_call
= acpi_processor_latency_notify
,
1136 int __cpuinit
acpi_processor_power_init(struct acpi_processor
*pr
,
1137 struct acpi_device
*device
)
1139 acpi_status status
= 0;
1140 static int first_run
;
1141 struct proc_dir_entry
*entry
= NULL
;
1146 dmi_check_system(processor_power_dmi_table
);
1147 if (max_cstate
< ACPI_C_STATES_MAX
)
1149 "ACPI: processor limited to max C-state %d\n",
1153 register_latency_notifier(&acpi_processor_latency_notifier
);
1160 if (acpi_gbl_FADT
.cst_control
&& !nocst
) {
1162 acpi_os_write_port(acpi_gbl_FADT
.smi_command
, acpi_gbl_FADT
.cst_control
, 8);
1163 if (ACPI_FAILURE(status
)) {
1164 ACPI_EXCEPTION((AE_INFO
, status
,
1165 "Notifying BIOS of _CST ability failed"));
1169 acpi_processor_get_power_info(pr
);
1172 * Install the idle handler if processor power management is supported.
1173 * Note that we use previously set idle handler will be used on
1174 * platforms that only support C1.
1176 if ((pr
->flags
.power
) && (!boot_option_idle_override
)) {
1177 printk(KERN_INFO PREFIX
"CPU%d (power states:", pr
->id
);
1178 for (i
= 1; i
<= pr
->power
.count
; i
++)
1179 if (pr
->power
.states
[i
].valid
)
1180 printk(" C%d[C%d]", i
,
1181 pr
->power
.states
[i
].type
);
1185 pm_idle_save
= pm_idle
;
1186 pm_idle
= acpi_processor_idle
;
1191 entry
= create_proc_entry(ACPI_PROCESSOR_FILE_POWER
,
1192 S_IRUGO
, acpi_device_dir(device
));
1196 entry
->proc_fops
= &acpi_processor_power_fops
;
1197 entry
->data
= acpi_driver_data(device
);
1198 entry
->owner
= THIS_MODULE
;
1201 pr
->flags
.power_setup_done
= 1;
1206 int acpi_processor_power_exit(struct acpi_processor
*pr
,
1207 struct acpi_device
*device
)
1210 pr
->flags
.power_setup_done
= 0;
1212 if (acpi_device_dir(device
))
1213 remove_proc_entry(ACPI_PROCESSOR_FILE_POWER
,
1214 acpi_device_dir(device
));
1216 /* Unregister the idle handler when processor #0 is removed. */
1218 pm_idle
= pm_idle_save
;
1221 * We are about to unload the current idle thread pm callback
1222 * (pm_idle), Wait for all processors to update cached/local
1223 * copies of pm_idle before proceeding.
1227 unregister_latency_notifier(&acpi_processor_latency_notifier
);