1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * processor_idle - idle state submodule to the ACPI processor driver
4 *
5 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
6 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
7 * Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de>
8 * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
9 * - Added processor hotplug support
10 * Copyright (C) 2005 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
11 * - Added support for C3 on SMP
12 */
13#define pr_fmt(fmt) "ACPI: " fmt
14
15#include <linux/module.h>
16#include <linux/acpi.h>
17#include <linux/dmi.h>
18#include <linux/sched.h> /* need_resched() */
19#include <linux/sort.h>
20#include <linux/tick.h>
21#include <linux/cpuidle.h>
22#include <linux/cpu.h>
23#include <linux/minmax.h>
24#include <linux/perf_event.h>
25#include <acpi/processor.h>
26#include <linux/context_tracking.h>
27
28/*
29 * Include the apic definitions for x86 to have the APIC timer related defines
30 * available also for UP (on SMP it gets magically included via linux/smp.h).
31 * asm/acpi.h is not an option, as it would require more include magic. Also
32 * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
33 */
34#ifdef CONFIG_X86
35#include <asm/apic.h>
36#include <asm/cpu.h>
37#endif
38
39#define ACPI_IDLE_STATE_START (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX) ? 1 : 0)
40
41static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
42module_param(max_cstate, uint, 0400);
43static bool nocst __read_mostly;
44module_param(nocst, bool, 0400);
45static bool bm_check_disable __read_mostly;
46module_param(bm_check_disable, bool, 0400);
47
48static unsigned int latency_factor __read_mostly = 2;
49module_param(latency_factor, uint, 0644);
50
51static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);
52
53struct cpuidle_driver acpi_idle_driver = {
54 .name = "acpi_idle",
55 .owner = THIS_MODULE,
56};
57
58#ifdef CONFIG_ACPI_PROCESSOR_CSTATE
59static
60DEFINE_PER_CPU(struct acpi_processor_cx * [CPUIDLE_STATE_MAX], acpi_cstate);
61
62static int disabled_by_idle_boot_param(void)
63{
64 return boot_option_idle_override == IDLE_POLL ||
65 boot_option_idle_override == IDLE_HALT;
66}
67
68/*
69 * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
70 * For now disable this. Probably a bug somewhere else.
71 *
72 * To skip this limit, boot/load with a large max_cstate limit.
73 */
74static int set_max_cstate(const struct dmi_system_id *id)
75{
76 if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
77 return 0;
78
79 pr_notice("%s detected - limiting to C%ld max_cstate."
80 " Override with \"processor.max_cstate=%d\"\n", id->ident,
81 (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
82
83 max_cstate = (long)id->driver_data;
84
85 return 0;
86}
87
88static const struct dmi_system_id processor_power_dmi_table[] = {
89 { set_max_cstate, "Clevo 5600D", {
90 DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
91 DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
92 (void *)2},
93 { set_max_cstate, "Pavilion zv5000", {
94 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
95 DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
96 (void *)1},
97 { set_max_cstate, "Asus L8400B", {
98 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
99 DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
100 (void *)1},
101 {},
102};
103
104
105/*
106 * Callers should disable interrupts before the call and enable
107 * interrupts after return.
108 */
109static void __cpuidle acpi_safe_halt(void)
110{
111 if (!tif_need_resched()) {
112 raw_safe_halt();
113 raw_local_irq_disable();
114 }
115}
116
117#ifdef ARCH_APICTIMER_STOPS_ON_C3
118
119/*
120 * Some BIOS implementations switch to C3 in the published C2 state.
121 * This seems to be a common problem on AMD boxen, but other vendors
122 * are affected too. We pick the most conservative approach: we assume
123 * that the local APIC stops in both C2 and C3.
124 */
125static void lapic_timer_check_state(int state, struct acpi_processor *pr,
126 struct acpi_processor_cx *cx)
127{
128 struct acpi_processor_power *pwr = &pr->power;
129 u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
130
131 if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
132 return;
133
134 if (boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E))
135 type = ACPI_STATE_C1;
136
137 /*
138 * Check, if one of the previous states already marked the lapic
139 * unstable
140 */
141 if (pwr->timer_broadcast_on_state < state)
142 return;
143
144 if (cx->type >= type)
145 pr->power.timer_broadcast_on_state = state;
146}
147
148static void __lapic_timer_propagate_broadcast(void *arg)
149{
150 struct acpi_processor *pr = arg;
151
152 if (pr->power.timer_broadcast_on_state < INT_MAX)
153 tick_broadcast_enable();
154 else
155 tick_broadcast_disable();
156}
157
158static void lapic_timer_propagate_broadcast(struct acpi_processor *pr)
159{
160 smp_call_function_single(cpuid: pr->id, func: __lapic_timer_propagate_broadcast,
161 info: (void *)pr, wait: 1);
162}
163
164/* Power(C) State timer broadcast control */
165static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
166 struct acpi_processor_cx *cx)
167{
168 return cx - pr->power.states >= pr->power.timer_broadcast_on_state;
169}
170
171#else
172
173static void lapic_timer_check_state(int state, struct acpi_processor *pr,
174 struct acpi_processor_cx *cstate) { }
175static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
176
177static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
178 struct acpi_processor_cx *cx)
179{
180 return false;
181}
182
183#endif
184
185#if defined(CONFIG_X86)
186static void tsc_check_state(int state)
187{
188 switch (boot_cpu_data.x86_vendor) {
189 case X86_VENDOR_HYGON:
190 case X86_VENDOR_AMD:
191 case X86_VENDOR_INTEL:
192 case X86_VENDOR_CENTAUR:
193 case X86_VENDOR_ZHAOXIN:
194 /*
195 * AMD Fam10h TSC will tick in all
196 * C/P/S0/S1 states when this bit is set.
197 */
198 if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
199 return;
200 fallthrough;
201 default:
202 /* TSC could halt in idle, so notify users */
203 if (state > ACPI_STATE_C1)
204 mark_tsc_unstable(reason: "TSC halts in idle");
205 }
206}
207#else
208static void tsc_check_state(int state) { return; }
209#endif
210
211static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
212{
213
214 if (!pr->pblk)
215 return -ENODEV;
216
217 /* if info is obtained from pblk/fadt, type equals state */
218 pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
219 pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
220
221#ifndef CONFIG_HOTPLUG_CPU
222 /*
223 * Check for P_LVL2_UP flag before entering C2 and above on
224 * an SMP system.
225 */
226 if ((num_online_cpus() > 1) &&
227 !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
228 return -ENODEV;
229#endif
230
231 /* determine C2 and C3 address from pblk */
232 pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
233 pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
234
235 /* determine latencies from FADT */
236 pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.c2_latency;
237 pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.c3_latency;
238
239 /*
240 * FADT specified C2 latency must be less than or equal to
241 * 100 microseconds.
242 */
243 if (acpi_gbl_FADT.c2_latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
244 acpi_handle_debug(pr->handle, "C2 latency too large [%d]\n",
245 acpi_gbl_FADT.c2_latency);
246 /* invalidate C2 */
247 pr->power.states[ACPI_STATE_C2].address = 0;
248 }
249
250 /*
251 * FADT supplied C3 latency must be less than or equal to
252 * 1000 microseconds.
253 */
254 if (acpi_gbl_FADT.c3_latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
255 acpi_handle_debug(pr->handle, "C3 latency too large [%d]\n",
256 acpi_gbl_FADT.c3_latency);
257 /* invalidate C3 */
258 pr->power.states[ACPI_STATE_C3].address = 0;
259 }
260
261 acpi_handle_debug(pr->handle, "lvl2[0x%08x] lvl3[0x%08x]\n",
262 pr->power.states[ACPI_STATE_C2].address,
263 pr->power.states[ACPI_STATE_C3].address);
264
265 snprintf(buf: pr->power.states[ACPI_STATE_C2].desc,
266 ACPI_CX_DESC_LEN, fmt: "ACPI P_LVL2 IOPORT 0x%x",
267 pr->power.states[ACPI_STATE_C2].address);
268 snprintf(buf: pr->power.states[ACPI_STATE_C3].desc,
269 ACPI_CX_DESC_LEN, fmt: "ACPI P_LVL3 IOPORT 0x%x",
270 pr->power.states[ACPI_STATE_C3].address);
271
272 return 0;
273}
274
275static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
276{
277 if (!pr->power.states[ACPI_STATE_C1].valid) {
278 /* set the first C-State to C1 */
279 /* all processors need to support C1 */
280 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
281 pr->power.states[ACPI_STATE_C1].valid = 1;
282 pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
283
284 snprintf(buf: pr->power.states[ACPI_STATE_C1].desc,
285 ACPI_CX_DESC_LEN, fmt: "ACPI HLT");
286 }
287 /* the C0 state only exists as a filler in our array */
288 pr->power.states[ACPI_STATE_C0].valid = 1;
289 return 0;
290}
291
292static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
293{
294 int ret;
295
296 if (nocst)
297 return -ENODEV;
298
299 ret = acpi_processor_evaluate_cst(handle: pr->handle, cpu: pr->id, info: &pr->power);
300 if (ret)
301 return ret;
302
303 if (!pr->power.count)
304 return -EFAULT;
305
306 pr->flags.has_cst = 1;
307 return 0;
308}
309
310static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
311 struct acpi_processor_cx *cx)
312{
313 static int bm_check_flag = -1;
314 static int bm_control_flag = -1;
315
316
317 if (!cx->address)
318 return;
319
320 /*
321 * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
322 * DMA transfers are used by any ISA device to avoid livelock.
323 * Note that we could disable Type-F DMA (as recommended by
324 * the erratum), but this is known to disrupt certain ISA
325 * devices thus we take the conservative approach.
326 */
327 if (errata.piix4.fdma) {
328 acpi_handle_debug(pr->handle,
329 "C3 not supported on PIIX4 with Type-F DMA\n");
330 return;
331 }
332
333 /* All the logic here assumes flags.bm_check is same across all CPUs */
334 if (bm_check_flag == -1) {
335 /* Determine whether bm_check is needed based on CPU */
336 acpi_processor_power_init_bm_check(flags: &(pr->flags), cpu: pr->id);
337 bm_check_flag = pr->flags.bm_check;
338 bm_control_flag = pr->flags.bm_control;
339 } else {
340 pr->flags.bm_check = bm_check_flag;
341 pr->flags.bm_control = bm_control_flag;
342 }
343
344 if (pr->flags.bm_check) {
345 if (!pr->flags.bm_control) {
346 if (pr->flags.has_cst != 1) {
347 /* bus mastering control is necessary */
348 acpi_handle_debug(pr->handle,
349 "C3 support requires BM control\n");
350 return;
351 } else {
352 /* Here we enter C3 without bus mastering */
353 acpi_handle_debug(pr->handle,
354 "C3 support without BM control\n");
355 }
356 }
357 } else {
358 /*
359 * WBINVD should be set in fadt, for C3 state to be
360 * supported on when bm_check is not required.
361 */
362 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
363 acpi_handle_debug(pr->handle,
364 "Cache invalidation should work properly"
365 " for C3 to be enabled on SMP systems\n");
366 return;
367 }
368 }
369
370 /*
371 * Otherwise we've met all of our C3 requirements.
372 * Normalize the C3 latency to expidite policy. Enable
373 * checking of bus mastering status (bm_check) so we can
374 * use this in our C3 policy
375 */
376 cx->valid = 1;
377
378 /*
379 * On older chipsets, BM_RLD needs to be set
380 * in order for Bus Master activity to wake the
381 * system from C3. Newer chipsets handle DMA
382 * during C3 automatically and BM_RLD is a NOP.
383 * In either case, the proper way to
384 * handle BM_RLD is to set it and leave it set.
385 */
386 acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, value: 1);
387}
388
389static int acpi_cst_latency_cmp(const void *a, const void *b)
390{
391 const struct acpi_processor_cx *x = a, *y = b;
392
393 if (!(x->valid && y->valid))
394 return 0;
395 if (x->latency > y->latency)
396 return 1;
397 if (x->latency < y->latency)
398 return -1;
399 return 0;
400}
401static void acpi_cst_latency_swap(void *a, void *b, int n)
402{
403 struct acpi_processor_cx *x = a, *y = b;
404
405 if (!(x->valid && y->valid))
406 return;
407 swap(x->latency, y->latency);
408}
409
410static int acpi_processor_power_verify(struct acpi_processor *pr)
411{
412 unsigned int i;
413 unsigned int working = 0;
414 unsigned int last_latency = 0;
415 unsigned int last_type = 0;
416 bool buggy_latency = false;
417
418 pr->power.timer_broadcast_on_state = INT_MAX;
419
420 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
421 struct acpi_processor_cx *cx = &pr->power.states[i];
422
423 switch (cx->type) {
424 case ACPI_STATE_C1:
425 cx->valid = 1;
426 break;
427
428 case ACPI_STATE_C2:
429 if (!cx->address)
430 break;
431 cx->valid = 1;
432 break;
433
434 case ACPI_STATE_C3:
435 acpi_processor_power_verify_c3(pr, cx);
436 break;
437 }
438 if (!cx->valid)
439 continue;
440 if (cx->type >= last_type && cx->latency < last_latency)
441 buggy_latency = true;
442 last_latency = cx->latency;
443 last_type = cx->type;
444
445 lapic_timer_check_state(state: i, pr, cx);
446 tsc_check_state(state: cx->type);
447 working++;
448 }
449
450 if (buggy_latency) {
451 pr_notice("FW issue: working around C-state latencies out of order\n");
452 sort(base: &pr->power.states[1], num: max_cstate,
453 size: sizeof(struct acpi_processor_cx),
454 cmp_func: acpi_cst_latency_cmp,
455 swap_func: acpi_cst_latency_swap);
456 }
457
458 lapic_timer_propagate_broadcast(pr);
459
460 return working;
461}
462
463static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
464{
465 unsigned int i;
466 int result;
467
468
469 /* NOTE: the idle thread may not be running while calling
470 * this function */
471
472 /* Zero initialize all the C-states info. */
473 memset(pr->power.states, 0, sizeof(pr->power.states));
474
475 result = acpi_processor_get_power_info_cst(pr);
476 if (result == -ENODEV)
477 result = acpi_processor_get_power_info_fadt(pr);
478
479 if (result)
480 return result;
481
482 acpi_processor_get_power_info_default(pr);
483
484 pr->power.count = acpi_processor_power_verify(pr);
485
486 /*
487 * if one state of type C2 or C3 is available, mark this
488 * CPU as being "idle manageable"
489 */
490 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
491 if (pr->power.states[i].valid) {
492 pr->power.count = i;
493 pr->flags.power = 1;
494 }
495 }
496
497 return 0;
498}
499
500/**
501 * acpi_idle_bm_check - checks if bus master activity was detected
502 */
503static int acpi_idle_bm_check(void)
504{
505 u32 bm_status = 0;
506
507 if (bm_check_disable)
508 return 0;
509
510 acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, return_value: &bm_status);
511 if (bm_status)
512 acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, value: 1);
513 /*
514 * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
515 * the true state of bus mastering activity; forcing us to
516 * manually check the BMIDEA bit of each IDE channel.
517 */
518 else if (errata.piix4.bmisx) {
519 if ((inb_p(port: errata.piix4.bmisx + 0x02) & 0x01)
520 || (inb_p(port: errata.piix4.bmisx + 0x0A) & 0x01))
521 bm_status = 1;
522 }
523 return bm_status;
524}
525
526static __cpuidle void io_idle(unsigned long addr)
527{
528 /* IO port based C-state */
529 inb(port: addr);
530
531#ifdef CONFIG_X86
532 /* No delay is needed if we are in guest */
533 if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
534 return;
535 /*
536 * Modern (>=Nehalem) Intel systems use ACPI via intel_idle,
537 * not this code. Assume that any Intel systems using this
538 * are ancient and may need the dummy wait. This also assumes
539 * that the motivating chipset issue was Intel-only.
540 */
541 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
542 return;
543#endif
544 /*
545 * Dummy wait op - must do something useless after P_LVL2 read
546 * because chipsets cannot guarantee that STPCLK# signal gets
547 * asserted in time to freeze execution properly
548 *
549 * This workaround has been in place since the original ACPI
550 * implementation was merged, circa 2002.
551 *
552 * If a profile is pointing to this instruction, please first
553 * consider moving your system to a more modern idle
554 * mechanism.
555 */
556 inl(port: acpi_gbl_FADT.xpm_timer_block.address);
557}
558
559/**
560 * acpi_idle_do_entry - enter idle state using the appropriate method
561 * @cx: cstate data
562 *
563 * Caller disables interrupt before call and enables interrupt after return.
564 */
565static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx)
566{
567 perf_lopwr_cb(lopwr_in: true);
568
569 if (cx->entry_method == ACPI_CSTATE_FFH) {
570 /* Call into architectural FFH based C-state */
571 acpi_processor_ffh_cstate_enter(cstate: cx);
572 } else if (cx->entry_method == ACPI_CSTATE_HALT) {
573 acpi_safe_halt();
574 } else {
575 io_idle(addr: cx->address);
576 }
577
578 perf_lopwr_cb(lopwr_in: false);
579}
580
581/**
582 * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
583 * @dev: the target CPU
584 * @index: the index of suggested state
585 */
586static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
587{
588 struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
589
590 ACPI_FLUSH_CPU_CACHE();
591
592 while (1) {
593
594 if (cx->entry_method == ACPI_CSTATE_HALT)
595 safe_halt();
596 else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
597 io_idle(addr: cx->address);
598 } else
599 return -ENODEV;
600 }
601
602 /* Never reached */
603 return 0;
604}
605
606static __always_inline bool acpi_idle_fallback_to_c1(struct acpi_processor *pr)
607{
608 return IS_ENABLED(CONFIG_HOTPLUG_CPU) && !pr->flags.has_cst &&
609 !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED);
610}
611
612static int c3_cpu_count;
613static DEFINE_RAW_SPINLOCK(c3_lock);
614
615/**
616 * acpi_idle_enter_bm - enters C3 with proper BM handling
617 * @drv: cpuidle driver
618 * @pr: Target processor
619 * @cx: Target state context
620 * @index: index of target state
621 */
622static int __cpuidle acpi_idle_enter_bm(struct cpuidle_driver *drv,
623 struct acpi_processor *pr,
624 struct acpi_processor_cx *cx,
625 int index)
626{
627 static struct acpi_processor_cx safe_cx = {
628 .entry_method = ACPI_CSTATE_HALT,
629 };
630
631 /*
632 * disable bus master
633 * bm_check implies we need ARB_DIS
634 * bm_control implies whether we can do ARB_DIS
635 *
636 * That leaves a case where bm_check is set and bm_control is not set.
637 * In that case we cannot do much, we enter C3 without doing anything.
638 */
639 bool dis_bm = pr->flags.bm_control;
640
641 instrumentation_begin();
642
643 /* If we can skip BM, demote to a safe state. */
644 if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
645 dis_bm = false;
646 index = drv->safe_state_index;
647 if (index >= 0) {
648 cx = this_cpu_read(acpi_cstate[index]);
649 } else {
650 cx = &safe_cx;
651 index = -EBUSY;
652 }
653 }
654
655 if (dis_bm) {
656 raw_spin_lock(&c3_lock);
657 c3_cpu_count++;
658 /* Disable bus master arbitration when all CPUs are in C3 */
659 if (c3_cpu_count == num_online_cpus())
660 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, value: 1);
661 raw_spin_unlock(&c3_lock);
662 }
663
664 ct_cpuidle_enter();
665
666 acpi_idle_do_entry(cx);
667
668 ct_cpuidle_exit();
669
670 /* Re-enable bus master arbitration */
671 if (dis_bm) {
672 raw_spin_lock(&c3_lock);
673 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, value: 0);
674 c3_cpu_count--;
675 raw_spin_unlock(&c3_lock);
676 }
677
678 instrumentation_end();
679
680 return index;
681}
682
683static int __cpuidle acpi_idle_enter(struct cpuidle_device *dev,
684 struct cpuidle_driver *drv, int index)
685{
686 struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
687 struct acpi_processor *pr;
688
689 pr = __this_cpu_read(processors);
690 if (unlikely(!pr))
691 return -EINVAL;
692
693 if (cx->type != ACPI_STATE_C1) {
694 if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check)
695 return acpi_idle_enter_bm(drv, pr, cx, index);
696
697 /* C2 to C1 demotion. */
698 if (acpi_idle_fallback_to_c1(pr) && num_online_cpus() > 1) {
699 index = ACPI_IDLE_STATE_START;
700 cx = per_cpu(acpi_cstate[index], dev->cpu);
701 }
702 }
703
704 if (cx->type == ACPI_STATE_C3)
705 ACPI_FLUSH_CPU_CACHE();
706
707 acpi_idle_do_entry(cx);
708
709 return index;
710}
711
712static int __cpuidle acpi_idle_enter_s2idle(struct cpuidle_device *dev,
713 struct cpuidle_driver *drv, int index)
714{
715 struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
716
717 if (cx->type == ACPI_STATE_C3) {
718 struct acpi_processor *pr = __this_cpu_read(processors);
719
720 if (unlikely(!pr))
721 return 0;
722
723 if (pr->flags.bm_check) {
724 u8 bm_sts_skip = cx->bm_sts_skip;
725
726 /* Don't check BM_STS, do an unconditional ARB_DIS for S2IDLE */
727 cx->bm_sts_skip = 1;
728 acpi_idle_enter_bm(drv, pr, cx, index);
729 cx->bm_sts_skip = bm_sts_skip;
730
731 return 0;
732 } else {
733 ACPI_FLUSH_CPU_CACHE();
734 }
735 }
736 acpi_idle_do_entry(cx);
737
738 return 0;
739}
740
741static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
742 struct cpuidle_device *dev)
743{
744 int i, count = ACPI_IDLE_STATE_START;
745 struct acpi_processor_cx *cx;
746 struct cpuidle_state *state;
747
748 if (max_cstate == 0)
749 max_cstate = 1;
750
751 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
752 state = &acpi_idle_driver.states[count];
753 cx = &pr->power.states[i];
754
755 if (!cx->valid)
756 continue;
757
758 per_cpu(acpi_cstate[count], dev->cpu) = cx;
759
760 if (lapic_timer_needs_broadcast(pr, cx))
761 state->flags |= CPUIDLE_FLAG_TIMER_STOP;
762
763 if (cx->type == ACPI_STATE_C3) {
764 state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;
765 if (pr->flags.bm_check)
766 state->flags |= CPUIDLE_FLAG_RCU_IDLE;
767 }
768
769 count++;
770 if (count == CPUIDLE_STATE_MAX)
771 break;
772 }
773
774 if (!count)
775 return -EINVAL;
776
777 return 0;
778}
779
780static int acpi_processor_setup_cstates(struct acpi_processor *pr)
781{
782 int i, count;
783 struct acpi_processor_cx *cx;
784 struct cpuidle_state *state;
785 struct cpuidle_driver *drv = &acpi_idle_driver;
786
787 if (max_cstate == 0)
788 max_cstate = 1;
789
790 if (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX)) {
791 cpuidle_poll_state_init(drv);
792 count = 1;
793 } else {
794 count = 0;
795 }
796
797 for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
798 cx = &pr->power.states[i];
799
800 if (!cx->valid)
801 continue;
802
803 state = &drv->states[count];
804 snprintf(buf: state->name, CPUIDLE_NAME_LEN, fmt: "C%d", i);
805 strscpy(p: state->desc, q: cx->desc, CPUIDLE_DESC_LEN);
806 state->exit_latency = cx->latency;
807 state->target_residency = cx->latency * latency_factor;
808 state->enter = acpi_idle_enter;
809
810 state->flags = 0;
811 if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2 ||
812 cx->type == ACPI_STATE_C3) {
813 state->enter_dead = acpi_idle_play_dead;
814 if (cx->type != ACPI_STATE_C3)
815 drv->safe_state_index = count;
816 }
817 /*
818 * Halt-induced C1 is not good for ->enter_s2idle, because it
819 * re-enables interrupts on exit. Moreover, C1 is generally not
820 * particularly interesting from the suspend-to-idle angle, so
821 * avoid C1 and the situations in which we may need to fall back
822 * to it altogether.
823 */
824 if (cx->type != ACPI_STATE_C1 && !acpi_idle_fallback_to_c1(pr))
825 state->enter_s2idle = acpi_idle_enter_s2idle;
826
827 count++;
828 if (count == CPUIDLE_STATE_MAX)
829 break;
830 }
831
832 drv->state_count = count;
833
834 if (!count)
835 return -EINVAL;
836
837 return 0;
838}
839
840static inline void acpi_processor_cstate_first_run_checks(void)
841{
842 static int first_run;
843
844 if (first_run)
845 return;
846 dmi_check_system(list: processor_power_dmi_table);
847 max_cstate = acpi_processor_cstate_check(max_cstate);
848 if (max_cstate < ACPI_C_STATES_MAX)
849 pr_notice("processor limited to max C-state %d\n", max_cstate);
850
851 first_run++;
852
853 if (nocst)
854 return;
855
856 acpi_processor_claim_cst_control();
857}
858#else
859
860static inline int disabled_by_idle_boot_param(void) { return 0; }
861static inline void acpi_processor_cstate_first_run_checks(void) { }
862static int acpi_processor_get_cstate_info(struct acpi_processor *pr)
863{
864 return -ENODEV;
865}
866
867static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
868 struct cpuidle_device *dev)
869{
870 return -EINVAL;
871}
872
873static int acpi_processor_setup_cstates(struct acpi_processor *pr)
874{
875 return -EINVAL;
876}
877
878#endif /* CONFIG_ACPI_PROCESSOR_CSTATE */
879
880struct acpi_lpi_states_array {
881 unsigned int size;
882 unsigned int composite_states_size;
883 struct acpi_lpi_state *entries;
884 struct acpi_lpi_state *composite_states[ACPI_PROCESSOR_MAX_POWER];
885};
886
887static int obj_get_integer(union acpi_object *obj, u32 *value)
888{
889 if (obj->type != ACPI_TYPE_INTEGER)
890 return -EINVAL;
891
892 *value = obj->integer.value;
893 return 0;
894}
895
896static int acpi_processor_evaluate_lpi(acpi_handle handle,
897 struct acpi_lpi_states_array *info)
898{
899 acpi_status status;
900 int ret = 0;
901 int pkg_count, state_idx = 1, loop;
902 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
903 union acpi_object *lpi_data;
904 struct acpi_lpi_state *lpi_state;
905
906 status = acpi_evaluate_object(object: handle, pathname: "_LPI", NULL, return_object_buffer: &buffer);
907 if (ACPI_FAILURE(status)) {
908 acpi_handle_debug(handle, "No _LPI, giving up\n");
909 return -ENODEV;
910 }
911
912 lpi_data = buffer.pointer;
913
914 /* There must be at least 4 elements = 3 elements + 1 package */
915 if (!lpi_data || lpi_data->type != ACPI_TYPE_PACKAGE ||
916 lpi_data->package.count < 4) {
917 pr_debug("not enough elements in _LPI\n");
918 ret = -ENODATA;
919 goto end;
920 }
921
922 pkg_count = lpi_data->package.elements[2].integer.value;
923
924 /* Validate number of power states. */
925 if (pkg_count < 1 || pkg_count != lpi_data->package.count - 3) {
926 pr_debug("count given by _LPI is not valid\n");
927 ret = -ENODATA;
928 goto end;
929 }
930
931 lpi_state = kcalloc(n: pkg_count, size: sizeof(*lpi_state), GFP_KERNEL);
932 if (!lpi_state) {
933 ret = -ENOMEM;
934 goto end;
935 }
936
937 info->size = pkg_count;
938 info->entries = lpi_state;
939
940 /* LPI States start at index 3 */
941 for (loop = 3; state_idx <= pkg_count; loop++, state_idx++, lpi_state++) {
942 union acpi_object *element, *pkg_elem, *obj;
943
944 element = &lpi_data->package.elements[loop];
945 if (element->type != ACPI_TYPE_PACKAGE || element->package.count < 7)
946 continue;
947
948 pkg_elem = element->package.elements;
949
950 obj = pkg_elem + 6;
951 if (obj->type == ACPI_TYPE_BUFFER) {
952 struct acpi_power_register *reg;
953
954 reg = (struct acpi_power_register *)obj->buffer.pointer;
955 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
956 reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)
957 continue;
958
959 lpi_state->address = reg->address;
960 lpi_state->entry_method =
961 reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE ?
962 ACPI_CSTATE_FFH : ACPI_CSTATE_SYSTEMIO;
963 } else if (obj->type == ACPI_TYPE_INTEGER) {
964 lpi_state->entry_method = ACPI_CSTATE_INTEGER;
965 lpi_state->address = obj->integer.value;
966 } else {
967 continue;
968 }
969
970 /* elements[7,8] skipped for now i.e. Residency/Usage counter*/
971
972 obj = pkg_elem + 9;
973 if (obj->type == ACPI_TYPE_STRING)
974 strscpy(p: lpi_state->desc, q: obj->string.pointer,
975 ACPI_CX_DESC_LEN);
976
977 lpi_state->index = state_idx;
978 if (obj_get_integer(obj: pkg_elem + 0, value: &lpi_state->min_residency)) {
979 pr_debug("No min. residency found, assuming 10 us\n");
980 lpi_state->min_residency = 10;
981 }
982
983 if (obj_get_integer(obj: pkg_elem + 1, value: &lpi_state->wake_latency)) {
984 pr_debug("No wakeup residency found, assuming 10 us\n");
985 lpi_state->wake_latency = 10;
986 }
987
988 if (obj_get_integer(obj: pkg_elem + 2, value: &lpi_state->flags))
989 lpi_state->flags = 0;
990
991 if (obj_get_integer(obj: pkg_elem + 3, value: &lpi_state->arch_flags))
992 lpi_state->arch_flags = 0;
993
994 if (obj_get_integer(obj: pkg_elem + 4, value: &lpi_state->res_cnt_freq))
995 lpi_state->res_cnt_freq = 1;
996
997 if (obj_get_integer(obj: pkg_elem + 5, value: &lpi_state->enable_parent_state))
998 lpi_state->enable_parent_state = 0;
999 }
1000
1001 acpi_handle_debug(handle, "Found %d power states\n", state_idx);
1002end:
1003 kfree(objp: buffer.pointer);
1004 return ret;
1005}
1006
1007/*
1008 * flat_state_cnt - the number of composite LPI states after the process of flattening
1009 */
1010static int flat_state_cnt;
1011
1012/**
1013 * combine_lpi_states - combine local and parent LPI states to form a composite LPI state
1014 *
1015 * @local: local LPI state
1016 * @parent: parent LPI state
1017 * @result: composite LPI state
1018 */
1019static bool combine_lpi_states(struct acpi_lpi_state *local,
1020 struct acpi_lpi_state *parent,
1021 struct acpi_lpi_state *result)
1022{
1023 if (parent->entry_method == ACPI_CSTATE_INTEGER) {
1024 if (!parent->address) /* 0 means autopromotable */
1025 return false;
1026 result->address = local->address + parent->address;
1027 } else {
1028 result->address = parent->address;
1029 }
1030
1031 result->min_residency = max(local->min_residency, parent->min_residency);
1032 result->wake_latency = local->wake_latency + parent->wake_latency;
1033 result->enable_parent_state = parent->enable_parent_state;
1034 result->entry_method = local->entry_method;
1035
1036 result->flags = parent->flags;
1037 result->arch_flags = parent->arch_flags;
1038 result->index = parent->index;
1039
1040 strscpy(p: result->desc, q: local->desc, ACPI_CX_DESC_LEN);
1041 strlcat(p: result->desc, q: "+", ACPI_CX_DESC_LEN);
1042 strlcat(p: result->desc, q: parent->desc, ACPI_CX_DESC_LEN);
1043 return true;
1044}
1045
1046#define ACPI_LPI_STATE_FLAGS_ENABLED BIT(0)
1047
1048static void stash_composite_state(struct acpi_lpi_states_array *curr_level,
1049 struct acpi_lpi_state *t)
1050{
1051 curr_level->composite_states[curr_level->composite_states_size++] = t;
1052}
1053
1054static int flatten_lpi_states(struct acpi_processor *pr,
1055 struct acpi_lpi_states_array *curr_level,
1056 struct acpi_lpi_states_array *prev_level)
1057{
1058 int i, j, state_count = curr_level->size;
1059 struct acpi_lpi_state *p, *t = curr_level->entries;
1060
1061 curr_level->composite_states_size = 0;
1062 for (j = 0; j < state_count; j++, t++) {
1063 struct acpi_lpi_state *flpi;
1064
1065 if (!(t->flags & ACPI_LPI_STATE_FLAGS_ENABLED))
1066 continue;
1067
1068 if (flat_state_cnt >= ACPI_PROCESSOR_MAX_POWER) {
1069 pr_warn("Limiting number of LPI states to max (%d)\n",
1070 ACPI_PROCESSOR_MAX_POWER);
1071 pr_warn("Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
1072 break;
1073 }
1074
1075 flpi = &pr->power.lpi_states[flat_state_cnt];
1076
1077 if (!prev_level) { /* leaf/processor node */
1078 memcpy(flpi, t, sizeof(*t));
1079 stash_composite_state(curr_level, t: flpi);
1080 flat_state_cnt++;
1081 continue;
1082 }
1083
1084 for (i = 0; i < prev_level->composite_states_size; i++) {
1085 p = prev_level->composite_states[i];
1086 if (t->index <= p->enable_parent_state &&
1087 combine_lpi_states(local: p, parent: t, result: flpi)) {
1088 stash_composite_state(curr_level, t: flpi);
1089 flat_state_cnt++;
1090 flpi++;
1091 }
1092 }
1093 }
1094
1095 kfree(objp: curr_level->entries);
1096 return 0;
1097}
1098
1099int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
1100{
1101 return -EOPNOTSUPP;
1102}
1103
1104static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
1105{
1106 int ret, i;
1107 acpi_status status;
1108 acpi_handle handle = pr->handle, pr_ahandle;
1109 struct acpi_device *d = NULL;
1110 struct acpi_lpi_states_array info[2], *tmp, *prev, *curr;
1111
1112 /* make sure our architecture has support */
1113 ret = acpi_processor_ffh_lpi_probe(cpu: pr->id);
1114 if (ret == -EOPNOTSUPP)
1115 return ret;
1116
1117 if (!osc_pc_lpi_support_confirmed)
1118 return -EOPNOTSUPP;
1119
1120 if (!acpi_has_method(handle, name: "_LPI"))
1121 return -EINVAL;
1122
1123 flat_state_cnt = 0;
1124 prev = &info[0];
1125 curr = &info[1];
1126 handle = pr->handle;
1127 ret = acpi_processor_evaluate_lpi(handle, info: prev);
1128 if (ret)
1129 return ret;
1130 flatten_lpi_states(pr, curr_level: prev, NULL);
1131
1132 status = acpi_get_parent(object: handle, out_handle: &pr_ahandle);
1133 while (ACPI_SUCCESS(status)) {
1134 d = acpi_fetch_acpi_dev(handle: pr_ahandle);
1135 if (!d)
1136 break;
1137
1138 handle = pr_ahandle;
1139
1140 if (strcmp(acpi_device_hid(device: d), ACPI_PROCESSOR_CONTAINER_HID))
1141 break;
1142
1143 /* can be optional ? */
1144 if (!acpi_has_method(handle, name: "_LPI"))
1145 break;
1146
1147 ret = acpi_processor_evaluate_lpi(handle, info: curr);
1148 if (ret)
1149 break;
1150
1151 /* flatten all the LPI states in this level of hierarchy */
1152 flatten_lpi_states(pr, curr_level: curr, prev_level: prev);
1153
1154 tmp = prev, prev = curr, curr = tmp;
1155
1156 status = acpi_get_parent(object: handle, out_handle: &pr_ahandle);
1157 }
1158
1159 pr->power.count = flat_state_cnt;
1160 /* reset the index after flattening */
1161 for (i = 0; i < pr->power.count; i++)
1162 pr->power.lpi_states[i].index = i;
1163
1164 /* Tell driver that _LPI is supported. */
1165 pr->flags.has_lpi = 1;
1166 pr->flags.power = 1;
1167
1168 return 0;
1169}
1170
1171int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
1172{
1173 return -ENODEV;
1174}
1175
1176/**
1177 * acpi_idle_lpi_enter - enters an ACPI any LPI state
1178 * @dev: the target CPU
1179 * @drv: cpuidle driver containing cpuidle state info
1180 * @index: index of target state
1181 *
1182 * Return: 0 for success or negative value for error
1183 */
1184static int acpi_idle_lpi_enter(struct cpuidle_device *dev,
1185 struct cpuidle_driver *drv, int index)
1186{
1187 struct acpi_processor *pr;
1188 struct acpi_lpi_state *lpi;
1189
1190 pr = __this_cpu_read(processors);
1191
1192 if (unlikely(!pr))
1193 return -EINVAL;
1194
1195 lpi = &pr->power.lpi_states[index];
1196 if (lpi->entry_method == ACPI_CSTATE_FFH)
1197 return acpi_processor_ffh_lpi_enter(lpi);
1198
1199 return -EINVAL;
1200}
1201
1202static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
1203{
1204 int i;
1205 struct acpi_lpi_state *lpi;
1206 struct cpuidle_state *state;
1207 struct cpuidle_driver *drv = &acpi_idle_driver;
1208
1209 if (!pr->flags.has_lpi)
1210 return -EOPNOTSUPP;
1211
1212 for (i = 0; i < pr->power.count && i < CPUIDLE_STATE_MAX; i++) {
1213 lpi = &pr->power.lpi_states[i];
1214
1215 state = &drv->states[i];
1216 snprintf(buf: state->name, CPUIDLE_NAME_LEN, fmt: "LPI-%d", i);
1217 strscpy(p: state->desc, q: lpi->desc, CPUIDLE_DESC_LEN);
1218 state->exit_latency = lpi->wake_latency;
1219 state->target_residency = lpi->min_residency;
1220 state->flags |= arch_get_idle_state_flags(arch_flags: lpi->arch_flags);
1221 if (i != 0 && lpi->entry_method == ACPI_CSTATE_FFH)
1222 state->flags |= CPUIDLE_FLAG_RCU_IDLE;
1223 state->enter = acpi_idle_lpi_enter;
1224 drv->safe_state_index = i;
1225 }
1226
1227 drv->state_count = i;
1228
1229 return 0;
1230}
1231
1232/**
1233 * acpi_processor_setup_cpuidle_states- prepares and configures cpuidle
1234 * global state data i.e. idle routines
1235 *
1236 * @pr: the ACPI processor
1237 */
1238static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
1239{
1240 int i;
1241 struct cpuidle_driver *drv = &acpi_idle_driver;
1242
1243 if (!pr->flags.power_setup_done || !pr->flags.power)
1244 return -EINVAL;
1245
1246 drv->safe_state_index = -1;
1247 for (i = ACPI_IDLE_STATE_START; i < CPUIDLE_STATE_MAX; i++) {
1248 drv->states[i].name[0] = '\0';
1249 drv->states[i].desc[0] = '\0';
1250 }
1251
1252 if (pr->flags.has_lpi)
1253 return acpi_processor_setup_lpi_states(pr);
1254
1255 return acpi_processor_setup_cstates(pr);
1256}
1257
1258/**
1259 * acpi_processor_setup_cpuidle_dev - prepares and configures CPUIDLE
1260 * device i.e. per-cpu data
1261 *
1262 * @pr: the ACPI processor
1263 * @dev : the cpuidle device
1264 */
1265static int acpi_processor_setup_cpuidle_dev(struct acpi_processor *pr,
1266 struct cpuidle_device *dev)
1267{
1268 if (!pr->flags.power_setup_done || !pr->flags.power || !dev)
1269 return -EINVAL;
1270
1271 dev->cpu = pr->id;
1272 if (pr->flags.has_lpi)
1273 return acpi_processor_ffh_lpi_probe(cpu: pr->id);
1274
1275 return acpi_processor_setup_cpuidle_cx(pr, dev);
1276}
1277
1278static int acpi_processor_get_power_info(struct acpi_processor *pr)
1279{
1280 int ret;
1281
1282 ret = acpi_processor_get_lpi_info(pr);
1283 if (ret)
1284 ret = acpi_processor_get_cstate_info(pr);
1285
1286 return ret;
1287}
1288
1289int acpi_processor_hotplug(struct acpi_processor *pr)
1290{
1291 int ret = 0;
1292 struct cpuidle_device *dev;
1293
1294 if (disabled_by_idle_boot_param())
1295 return 0;
1296
1297 if (!pr->flags.power_setup_done)
1298 return -ENODEV;
1299
1300 dev = per_cpu(acpi_cpuidle_device, pr->id);
1301 cpuidle_pause_and_lock();
1302 cpuidle_disable_device(dev);
1303 ret = acpi_processor_get_power_info(pr);
1304 if (!ret && pr->flags.power) {
1305 acpi_processor_setup_cpuidle_dev(pr, dev);
1306 ret = cpuidle_enable_device(dev);
1307 }
1308 cpuidle_resume_and_unlock();
1309
1310 return ret;
1311}
1312
1313int acpi_processor_power_state_has_changed(struct acpi_processor *pr)
1314{
1315 int cpu;
1316 struct acpi_processor *_pr;
1317 struct cpuidle_device *dev;
1318
1319 if (disabled_by_idle_boot_param())
1320 return 0;
1321
1322 if (!pr->flags.power_setup_done)
1323 return -ENODEV;
1324
1325 /*
1326 * FIXME: Design the ACPI notification to make it once per
1327 * system instead of once per-cpu. This condition is a hack
1328 * to make the code that updates C-States be called once.
1329 */
1330
1331 if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {
1332
1333 /* Protect against cpu-hotplug */
1334 cpus_read_lock();
1335 cpuidle_pause_and_lock();
1336
1337 /* Disable all cpuidle devices */
1338 for_each_online_cpu(cpu) {
1339 _pr = per_cpu(processors, cpu);
1340 if (!_pr || !_pr->flags.power_setup_done)
1341 continue;
1342 dev = per_cpu(acpi_cpuidle_device, cpu);
1343 cpuidle_disable_device(dev);
1344 }
1345
1346 /* Populate Updated C-state information */
1347 acpi_processor_get_power_info(pr);
1348 acpi_processor_setup_cpuidle_states(pr);
1349
1350 /* Enable all cpuidle devices */
1351 for_each_online_cpu(cpu) {
1352 _pr = per_cpu(processors, cpu);
1353 if (!_pr || !_pr->flags.power_setup_done)
1354 continue;
1355 acpi_processor_get_power_info(pr: _pr);
1356 if (_pr->flags.power) {
1357 dev = per_cpu(acpi_cpuidle_device, cpu);
1358 acpi_processor_setup_cpuidle_dev(pr: _pr, dev);
1359 cpuidle_enable_device(dev);
1360 }
1361 }
1362 cpuidle_resume_and_unlock();
1363 cpus_read_unlock();
1364 }
1365
1366 return 0;
1367}
1368
1369static int acpi_processor_registered;
1370
1371int acpi_processor_power_init(struct acpi_processor *pr)
1372{
1373 int retval;
1374 struct cpuidle_device *dev;
1375
1376 if (disabled_by_idle_boot_param())
1377 return 0;
1378
1379 acpi_processor_cstate_first_run_checks();
1380
1381 if (!acpi_processor_get_power_info(pr))
1382 pr->flags.power_setup_done = 1;
1383
1384 /*
1385 * Install the idle handler if processor power management is supported.
1386 * Note that we use previously set idle handler will be used on
1387 * platforms that only support C1.
1388 */
1389 if (pr->flags.power) {
1390 /* Register acpi_idle_driver if not already registered */
1391 if (!acpi_processor_registered) {
1392 acpi_processor_setup_cpuidle_states(pr);
1393 retval = cpuidle_register_driver(drv: &acpi_idle_driver);
1394 if (retval)
1395 return retval;
1396 pr_debug("%s registered with cpuidle\n",
1397 acpi_idle_driver.name);
1398 }
1399
1400 dev = kzalloc(size: sizeof(*dev), GFP_KERNEL);
1401 if (!dev)
1402 return -ENOMEM;
1403 per_cpu(acpi_cpuidle_device, pr->id) = dev;
1404
1405 acpi_processor_setup_cpuidle_dev(pr, dev);
1406
1407 /* Register per-cpu cpuidle_device. Cpuidle driver
1408 * must already be registered before registering device
1409 */
1410 retval = cpuidle_register_device(dev);
1411 if (retval) {
1412 if (acpi_processor_registered == 0)
1413 cpuidle_unregister_driver(drv: &acpi_idle_driver);
1414 return retval;
1415 }
1416 acpi_processor_registered++;
1417 }
1418 return 0;
1419}
1420
1421int acpi_processor_power_exit(struct acpi_processor *pr)
1422{
1423 struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);
1424
1425 if (disabled_by_idle_boot_param())
1426 return 0;
1427
1428 if (pr->flags.power) {
1429 cpuidle_unregister_device(dev);
1430 acpi_processor_registered--;
1431 if (acpi_processor_registered == 0)
1432 cpuidle_unregister_driver(drv: &acpi_idle_driver);
1433 }
1434
1435 pr->flags.power_setup_done = 0;
1436 return 0;
1437}
1438

source code of linux/drivers/acpi/processor_idle.c