ACPI / cpuidle: Fix NULL pointer issues when cpuidle is disabled
[opensuse:kernel.git] / drivers / acpi / processor_idle.c
1 /*
2  * processor_idle - idle state submodule to the ACPI processor driver
3  *
4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6  *  Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de>
7  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
8  *                      - Added processor hotplug support
9  *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
10  *                      - Added support for C3 on SMP
11  *
12  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
13  *
14  *  This program is free software; you can redistribute it and/or modify
15  *  it under the terms of the GNU General Public License as published by
16  *  the Free Software Foundation; either version 2 of the License, or (at
17  *  your option) any later version.
18  *
19  *  This program is distributed in the hope that it will be useful, but
20  *  WITHOUT ANY WARRANTY; without even the implied warranty of
21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
22  *  General Public License for more details.
23  *
24  *  You should have received a copy of the GNU General Public License along
25  *  with this program; if not, write to the Free Software Foundation, Inc.,
26  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
27  *
28  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
29  */
30
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/init.h>
34 #include <linux/cpufreq.h>
35 #include <linux/slab.h>
36 #include <linux/acpi.h>
37 #include <linux/dmi.h>
38 #include <linux/moduleparam.h>
39 #include <linux/sched.h>        /* need_resched() */
40 #include <linux/pm_qos.h>
41 #include <linux/clockchips.h>
42 #include <linux/cpuidle.h>
43 #include <linux/irqflags.h>
44
45 /*
46  * Include the apic definitions for x86 to have the APIC timer related defines
47  * available also for UP (on SMP it gets magically included via linux/smp.h).
48  * asm/acpi.h is not an option, as it would require more include magic. Also
49  * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
50  */
51 #ifdef CONFIG_X86
52 #include <asm/apic.h>
53 #endif
54
55 #include <asm/io.h>
56 #include <asm/uaccess.h>
57
58 #include <acpi/acpi_bus.h>
59 #include <acpi/processor.h>
60 #include <asm/processor.h>
61
62 #define PREFIX "ACPI: "
63
64 #define ACPI_PROCESSOR_CLASS            "processor"
65 #define _COMPONENT              ACPI_PROCESSOR_COMPONENT
66 ACPI_MODULE_NAME("processor_idle");
67 #define PM_TIMER_TICK_NS                (1000000000ULL/PM_TIMER_FREQUENCY)
68 #define C2_OVERHEAD                     1       /* 1us */
69 #define C3_OVERHEAD                     1       /* 1us */
70 #define PM_TIMER_TICKS_TO_US(p)         (((p) * 1000)/(PM_TIMER_FREQUENCY/1000))
71
72 static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
73 module_param(max_cstate, uint, 0000);
74 static unsigned int nocst __read_mostly;
75 module_param(nocst, uint, 0000);
76 static int bm_check_disable __read_mostly;
77 module_param(bm_check_disable, uint, 0000);
78
79 static unsigned int latency_factor __read_mostly = 2;
80 module_param(latency_factor, uint, 0644);
81
82 static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);
83
84 static int disabled_by_idle_boot_param(void)
85 {
86         return boot_option_idle_override == IDLE_POLL ||
87                 boot_option_idle_override == IDLE_FORCE_MWAIT ||
88                 boot_option_idle_override == IDLE_HALT;
89 }
90
91 /*
92  * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
93  * For now disable this. Probably a bug somewhere else.
94  *
95  * To skip this limit, boot/load with a large max_cstate limit.
96  */
97 static int set_max_cstate(const struct dmi_system_id *id)
98 {
99         if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
100                 return 0;
101
102         printk(KERN_NOTICE PREFIX "%s detected - limiting to C%ld max_cstate."
103                " Override with \"processor.max_cstate=%d\"\n", id->ident,
104                (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);
105
106         max_cstate = (long)id->driver_data;
107
108         return 0;
109 }
110
111 /* Actually this shouldn't be __cpuinitdata, would be better to fix the
112    callers to only run once -AK */
113 static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = {
114         { set_max_cstate, "Clevo 5600D", {
115           DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
116           DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},
117          (void *)2},
118         { set_max_cstate, "Pavilion zv5000", {
119           DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
120           DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
121          (void *)1},
122         { set_max_cstate, "Asus L8400B", {
123           DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
124           DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
125          (void *)1},
126         {},
127 };
128
129
130 /*
131  * Callers should disable interrupts before the call and enable
132  * interrupts after return.
133  */
134 static void acpi_safe_halt(void)
135 {
136         current_thread_info()->status &= ~TS_POLLING;
137         /*
138          * TS_POLLING-cleared state must be visible before we
139          * test NEED_RESCHED:
140          */
141         smp_mb();
142         if (!need_resched()) {
143                 safe_halt();
144                 local_irq_disable();
145         }
146         current_thread_info()->status |= TS_POLLING;
147 }
148
149 #ifdef ARCH_APICTIMER_STOPS_ON_C3
150
151 /*
152  * Some BIOS implementations switch to C3 in the published C2 state.
153  * This seems to be a common problem on AMD boxen, but other vendors
154  * are affected too. We pick the most conservative approach: we assume
155  * that the local APIC stops in both C2 and C3.
156  */
157 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
158                                    struct acpi_processor_cx *cx)
159 {
160         struct acpi_processor_power *pwr = &pr->power;
161         u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;
162
163         if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
164                 return;
165
166         if (amd_e400_c1e_detected)
167                 type = ACPI_STATE_C1;
168
169         /*
170          * Check, if one of the previous states already marked the lapic
171          * unstable
172          */
173         if (pwr->timer_broadcast_on_state < state)
174                 return;
175
176         if (cx->type >= type)
177                 pr->power.timer_broadcast_on_state = state;
178 }
179
180 static void __lapic_timer_propagate_broadcast(void *arg)
181 {
182         struct acpi_processor *pr = (struct acpi_processor *) arg;
183         unsigned long reason;
184
185         reason = pr->power.timer_broadcast_on_state < INT_MAX ?
186                 CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF;
187
188         clockevents_notify(reason, &pr->id);
189 }
190
191 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr)
192 {
193         smp_call_function_single(pr->id, __lapic_timer_propagate_broadcast,
194                                  (void *)pr, 1);
195 }
196
197 /* Power(C) State timer broadcast control */
198 static void lapic_timer_state_broadcast(struct acpi_processor *pr,
199                                        struct acpi_processor_cx *cx,
200                                        int broadcast)
201 {
202         int state = cx - pr->power.states;
203
204         if (state >= pr->power.timer_broadcast_on_state) {
205                 unsigned long reason;
206
207                 reason = broadcast ?  CLOCK_EVT_NOTIFY_BROADCAST_ENTER :
208                         CLOCK_EVT_NOTIFY_BROADCAST_EXIT;
209                 clockevents_notify(reason, &pr->id);
210         }
211 }
212
213 #else
214
215 static void lapic_timer_check_state(int state, struct acpi_processor *pr,
216                                    struct acpi_processor_cx *cstate) { }
217 static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }
218 static void lapic_timer_state_broadcast(struct acpi_processor *pr,
219                                        struct acpi_processor_cx *cx,
220                                        int broadcast)
221 {
222 }
223
224 #endif
225
226 static u32 saved_bm_rld;
227
228 static void acpi_idle_bm_rld_save(void)
229 {
230         acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &saved_bm_rld);
231 }
232 static void acpi_idle_bm_rld_restore(void)
233 {
234         u32 resumed_bm_rld;
235
236         acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &resumed_bm_rld);
237
238         if (resumed_bm_rld != saved_bm_rld)
239                 acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, saved_bm_rld);
240 }
241
242 int acpi_processor_suspend(struct device *dev)
243 {
244         acpi_idle_bm_rld_save();
245         return 0;
246 }
247
248 int acpi_processor_resume(struct device *dev)
249 {
250         acpi_idle_bm_rld_restore();
251         return 0;
252 }
253
254 #if defined(CONFIG_X86)
255 static void tsc_check_state(int state)
256 {
257         switch (boot_cpu_data.x86_vendor) {
258         case X86_VENDOR_AMD:
259         case X86_VENDOR_INTEL:
260                 /*
261                  * AMD Fam10h TSC will tick in all
262                  * C/P/S0/S1 states when this bit is set.
263                  */
264                 if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
265                         return;
266
267                 /*FALL THROUGH*/
268         default:
269                 /* TSC could halt in idle, so notify users */
270                 if (state > ACPI_STATE_C1)
271                         mark_tsc_unstable("TSC halts in idle");
272         }
273 }
274 #else
275 static void tsc_check_state(int state) { return; }
276 #endif
277
278 static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
279 {
280
281         if (!pr)
282                 return -EINVAL;
283
284         if (!pr->pblk)
285                 return -ENODEV;
286
287         /* if info is obtained from pblk/fadt, type equals state */
288         pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
289         pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;
290
291 #ifndef CONFIG_HOTPLUG_CPU
292         /*
293          * Check for P_LVL2_UP flag before entering C2 and above on
294          * an SMP system.
295          */
296         if ((num_online_cpus() > 1) &&
297             !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
298                 return -ENODEV;
299 #endif
300
301         /* determine C2 and C3 address from pblk */
302         pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
303         pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
304
305         /* determine latencies from FADT */
306         pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.c2_latency;
307         pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.c3_latency;
308
309         /*
310          * FADT specified C2 latency must be less than or equal to
311          * 100 microseconds.
312          */
313         if (acpi_gbl_FADT.c2_latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {
314                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
315                         "C2 latency too large [%d]\n", acpi_gbl_FADT.c2_latency));
316                 /* invalidate C2 */
317                 pr->power.states[ACPI_STATE_C2].address = 0;
318         }
319
320         /*
321          * FADT supplied C3 latency must be less than or equal to
322          * 1000 microseconds.
323          */
324         if (acpi_gbl_FADT.c3_latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {
325                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
326                         "C3 latency too large [%d]\n", acpi_gbl_FADT.c3_latency));
327                 /* invalidate C3 */
328                 pr->power.states[ACPI_STATE_C3].address = 0;
329         }
330
331         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
332                           "lvl2[0x%08x] lvl3[0x%08x]\n",
333                           pr->power.states[ACPI_STATE_C2].address,
334                           pr->power.states[ACPI_STATE_C3].address));
335
336         return 0;
337 }
338
339 static int acpi_processor_get_power_info_default(struct acpi_processor *pr)
340 {
341         if (!pr->power.states[ACPI_STATE_C1].valid) {
342                 /* set the first C-State to C1 */
343                 /* all processors need to support C1 */
344                 pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
345                 pr->power.states[ACPI_STATE_C1].valid = 1;
346                 pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;
347         }
348         /* the C0 state only exists as a filler in our array */
349         pr->power.states[ACPI_STATE_C0].valid = 1;
350         return 0;
351 }
352
353 static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
354 {
355         acpi_status status = 0;
356         u64 count;
357         int current_count;
358         int i;
359         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
360         union acpi_object *cst;
361
362
363         if (nocst)
364                 return -ENODEV;
365
366         current_count = 0;
367
368         status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer);
369         if (ACPI_FAILURE(status)) {
370                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _CST, giving up\n"));
371                 return -ENODEV;
372         }
373
374         cst = buffer.pointer;
375
376         /* There must be at least 2 elements */
377         if (!cst || (cst->type != ACPI_TYPE_PACKAGE) || cst->package.count < 2) {
378                 printk(KERN_ERR PREFIX "not enough elements in _CST\n");
379                 status = -EFAULT;
380                 goto end;
381         }
382
383         count = cst->package.elements[0].integer.value;
384
385         /* Validate number of power states. */
386         if (count < 1 || count != cst->package.count - 1) {
387                 printk(KERN_ERR PREFIX "count given by _CST is not valid\n");
388                 status = -EFAULT;
389                 goto end;
390         }
391
392         /* Tell driver that at least _CST is supported. */
393         pr->flags.has_cst = 1;
394
395         for (i = 1; i <= count; i++) {
396                 union acpi_object *element;
397                 union acpi_object *obj;
398                 struct acpi_power_register *reg;
399                 struct acpi_processor_cx cx;
400
401                 memset(&cx, 0, sizeof(cx));
402
403                 element = &(cst->package.elements[i]);
404                 if (element->type != ACPI_TYPE_PACKAGE)
405                         continue;
406
407                 if (element->package.count != 4)
408                         continue;
409
410                 obj = &(element->package.elements[0]);
411
412                 if (obj->type != ACPI_TYPE_BUFFER)
413                         continue;
414
415                 reg = (struct acpi_power_register *)obj->buffer.pointer;
416
417                 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
418                     (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE))
419                         continue;
420
421                 /* There should be an easy way to extract an integer... */
422                 obj = &(element->package.elements[1]);
423                 if (obj->type != ACPI_TYPE_INTEGER)
424                         continue;
425
426                 cx.type = obj->integer.value;
427                 /*
428                  * Some buggy BIOSes won't list C1 in _CST -
429                  * Let acpi_processor_get_power_info_default() handle them later
430                  */
431                 if (i == 1 && cx.type != ACPI_STATE_C1)
432                         current_count++;
433
434                 cx.address = reg->address;
435                 cx.index = current_count + 1;
436
437                 cx.entry_method = ACPI_CSTATE_SYSTEMIO;
438                 if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
439                         if (acpi_processor_ffh_cstate_probe
440                                         (pr->id, &cx, reg) == 0) {
441                                 cx.entry_method = ACPI_CSTATE_FFH;
442                         } else if (cx.type == ACPI_STATE_C1) {
443                                 /*
444                                  * C1 is a special case where FIXED_HARDWARE
445                                  * can be handled in non-MWAIT way as well.
446                                  * In that case, save this _CST entry info.
447                                  * Otherwise, ignore this info and continue.
448                                  */
449                                 cx.entry_method = ACPI_CSTATE_HALT;
450                                 snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
451                         } else {
452                                 continue;
453                         }
454                         if (cx.type == ACPI_STATE_C1 &&
455                             (boot_option_idle_override == IDLE_NOMWAIT)) {
456                                 /*
457                                  * In most cases the C1 space_id obtained from
458                                  * _CST object is FIXED_HARDWARE access mode.
459                                  * But when the option of idle=halt is added,
460                                  * the entry_method type should be changed from
461                                  * CSTATE_FFH to CSTATE_HALT.
462                                  * When the option of idle=nomwait is added,
463                                  * the C1 entry_method type should be
464                                  * CSTATE_HALT.
465                                  */
466                                 cx.entry_method = ACPI_CSTATE_HALT;
467                                 snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
468                         }
469                 } else {
470                         snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
471                                  cx.address);
472                 }
473
474                 if (cx.type == ACPI_STATE_C1) {
475                         cx.valid = 1;
476                 }
477
478                 obj = &(element->package.elements[2]);
479                 if (obj->type != ACPI_TYPE_INTEGER)
480                         continue;
481
482                 cx.latency = obj->integer.value;
483
484                 obj = &(element->package.elements[3]);
485                 if (obj->type != ACPI_TYPE_INTEGER)
486                         continue;
487
488                 current_count++;
489                 memcpy(&(pr->power.states[current_count]), &cx, sizeof(cx));
490
491                 /*
492                  * We support total ACPI_PROCESSOR_MAX_POWER - 1
493                  * (From 1 through ACPI_PROCESSOR_MAX_POWER - 1)
494                  */
495                 if (current_count >= (ACPI_PROCESSOR_MAX_POWER - 1)) {
496                         printk(KERN_WARNING
497                                "Limiting number of power states to max (%d)\n",
498                                ACPI_PROCESSOR_MAX_POWER);
499                         printk(KERN_WARNING
500                                "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
501                         break;
502                 }
503         }
504
505         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d power states\n",
506                           current_count));
507
508         /* Validate number of power states discovered */
509         if (current_count < 2)
510                 status = -EFAULT;
511
512       end:
513         kfree(buffer.pointer);
514
515         return status;
516 }
517
518 static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
519                                            struct acpi_processor_cx *cx)
520 {
521         static int bm_check_flag = -1;
522         static int bm_control_flag = -1;
523
524
525         if (!cx->address)
526                 return;
527
528         /*
529          * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
530          * DMA transfers are used by any ISA device to avoid livelock.
531          * Note that we could disable Type-F DMA (as recommended by
532          * the erratum), but this is known to disrupt certain ISA
533          * devices thus we take the conservative approach.
534          */
535         else if (errata.piix4.fdma) {
536                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
537                                   "C3 not supported on PIIX4 with Type-F DMA\n"));
538                 return;
539         }
540
541         /* All the logic here assumes flags.bm_check is same across all CPUs */
542         if (bm_check_flag == -1) {
543                 /* Determine whether bm_check is needed based on CPU  */
544                 acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
545                 bm_check_flag = pr->flags.bm_check;
546                 bm_control_flag = pr->flags.bm_control;
547         } else {
548                 pr->flags.bm_check = bm_check_flag;
549                 pr->flags.bm_control = bm_control_flag;
550         }
551
552         if (pr->flags.bm_check) {
553                 if (!pr->flags.bm_control) {
554                         if (pr->flags.has_cst != 1) {
555                                 /* bus mastering control is necessary */
556                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
557                                         "C3 support requires BM control\n"));
558                                 return;
559                         } else {
560                                 /* Here we enter C3 without bus mastering */
561                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
562                                         "C3 support without BM control\n"));
563                         }
564                 }
565         } else {
566                 /*
567                  * WBINVD should be set in fadt, for C3 state to be
568                  * supported on when bm_check is not required.
569                  */
570                 if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {
571                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
572                                           "Cache invalidation should work properly"
573                                           " for C3 to be enabled on SMP systems\n"));
574                         return;
575                 }
576         }
577
578         /*
579          * Otherwise we've met all of our C3 requirements.
580          * Normalize the C3 latency to expidite policy.  Enable
581          * checking of bus mastering status (bm_check) so we can
582          * use this in our C3 policy
583          */
584         cx->valid = 1;
585
586         /*
587          * On older chipsets, BM_RLD needs to be set
588          * in order for Bus Master activity to wake the
589          * system from C3.  Newer chipsets handle DMA
590          * during C3 automatically and BM_RLD is a NOP.
591          * In either case, the proper way to
592          * handle BM_RLD is to set it and leave it set.
593          */
594         acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
595
596         return;
597 }
598
599 static int acpi_processor_power_verify(struct acpi_processor *pr)
600 {
601         unsigned int i;
602         unsigned int working = 0;
603
604         pr->power.timer_broadcast_on_state = INT_MAX;
605
606         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
607                 struct acpi_processor_cx *cx = &pr->power.states[i];
608
609                 switch (cx->type) {
610                 case ACPI_STATE_C1:
611                         cx->valid = 1;
612                         break;
613
614                 case ACPI_STATE_C2:
615                         if (!cx->address)
616                                 break;
617                         cx->valid = 1; 
618                         break;
619
620                 case ACPI_STATE_C3:
621                         acpi_processor_power_verify_c3(pr, cx);
622                         break;
623                 }
624                 if (!cx->valid)
625                         continue;
626
627                 lapic_timer_check_state(i, pr, cx);
628                 tsc_check_state(cx->type);
629                 working++;
630         }
631
632         lapic_timer_propagate_broadcast(pr);
633
634         return (working);
635 }
636
637 static int acpi_processor_get_power_info(struct acpi_processor *pr)
638 {
639         unsigned int i;
640         int result;
641
642
643         /* NOTE: the idle thread may not be running while calling
644          * this function */
645
646         /* Zero initialize all the C-states info. */
647         memset(pr->power.states, 0, sizeof(pr->power.states));
648
649         result = acpi_processor_get_power_info_cst(pr);
650         if (result == -ENODEV)
651                 result = acpi_processor_get_power_info_fadt(pr);
652
653         if (result)
654                 return result;
655
656         acpi_processor_get_power_info_default(pr);
657
658         pr->power.count = acpi_processor_power_verify(pr);
659
660         /*
661          * if one state of type C2 or C3 is available, mark this
662          * CPU as being "idle manageable"
663          */
664         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
665                 if (pr->power.states[i].valid) {
666                         pr->power.count = i;
667                         if (pr->power.states[i].type >= ACPI_STATE_C2)
668                                 pr->flags.power = 1;
669                 }
670         }
671
672         return 0;
673 }
674
675 /**
676  * acpi_idle_bm_check - checks if bus master activity was detected
677  */
678 static int acpi_idle_bm_check(void)
679 {
680         u32 bm_status = 0;
681
682         if (bm_check_disable)
683                 return 0;
684
685         acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
686         if (bm_status)
687                 acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
688         /*
689          * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
690          * the true state of bus mastering activity; forcing us to
691          * manually check the BMIDEA bit of each IDE channel.
692          */
693         else if (errata.piix4.bmisx) {
694                 if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
695                     || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
696                         bm_status = 1;
697         }
698         return bm_status;
699 }
700
701 /**
702  * acpi_idle_do_entry - a helper function that does C2 and C3 type entry
703  * @cx: cstate data
704  *
705  * Caller disables interrupt before call and enables interrupt after return.
706  */
707 static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx)
708 {
709         /* Don't trace irqs off for idle */
710         stop_critical_timings();
711         if (cx->entry_method == ACPI_CSTATE_FFH) {
712                 /* Call into architectural FFH based C-state */
713                 acpi_processor_ffh_cstate_enter(cx);
714         } else if (cx->entry_method == ACPI_CSTATE_HALT) {
715                 acpi_safe_halt();
716         } else {
717                 /* IO port based C-state */
718                 inb(cx->address);
719                 /* Dummy wait op - must do something useless after P_LVL2 read
720                    because chipsets cannot guarantee that STPCLK# signal
721                    gets asserted in time to freeze execution properly. */
722                 inl(acpi_gbl_FADT.xpm_timer_block.address);
723         }
724         start_critical_timings();
725 }
726
727 /**
728  * acpi_idle_enter_c1 - enters an ACPI C1 state-type
729  * @dev: the target CPU
730  * @drv: cpuidle driver containing cpuidle state info
731  * @index: index of target state
732  *
733  * This is equivalent to the HALT instruction.
734  */
735 static int acpi_idle_enter_c1(struct cpuidle_device *dev,
736                 struct cpuidle_driver *drv, int index)
737 {
738         ktime_t  kt1, kt2;
739         s64 idle_time;
740         struct acpi_processor *pr;
741         struct cpuidle_state_usage *state_usage = &dev->states_usage[index];
742         struct acpi_processor_cx *cx = cpuidle_get_statedata(state_usage);
743
744         pr = __this_cpu_read(processors);
745         dev->last_residency = 0;
746
747         if (unlikely(!pr))
748                 return -EINVAL;
749
750         local_irq_disable();
751
752
753         lapic_timer_state_broadcast(pr, cx, 1);
754         kt1 = ktime_get_real();
755         acpi_idle_do_entry(cx);
756         kt2 = ktime_get_real();
757         idle_time =  ktime_to_us(ktime_sub(kt2, kt1));
758
759         /* Update device last_residency*/
760         dev->last_residency = (int)idle_time;
761
762         local_irq_enable();
763         lapic_timer_state_broadcast(pr, cx, 0);
764
765         return index;
766 }
767
768
769 /**
770  * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
771  * @dev: the target CPU
772  * @index: the index of suggested state
773  */
774 static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
775 {
776         struct cpuidle_state_usage *state_usage = &dev->states_usage[index];
777         struct acpi_processor_cx *cx = cpuidle_get_statedata(state_usage);
778
779         ACPI_FLUSH_CPU_CACHE();
780
781         while (1) {
782
783                 if (cx->entry_method == ACPI_CSTATE_HALT)
784                         safe_halt();
785                 else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
786                         inb(cx->address);
787                         /* See comment in acpi_idle_do_entry() */
788                         inl(acpi_gbl_FADT.xpm_timer_block.address);
789                 } else
790                         return -ENODEV;
791         }
792
793         /* Never reached */
794         return 0;
795 }
796
797 /**
798  * acpi_idle_enter_simple - enters an ACPI state without BM handling
799  * @dev: the target CPU
800  * @drv: cpuidle driver with cpuidle state information
801  * @index: the index of suggested state
802  */
803 static int acpi_idle_enter_simple(struct cpuidle_device *dev,
804                 struct cpuidle_driver *drv, int index)
805 {
806         struct acpi_processor *pr;
807         struct cpuidle_state_usage *state_usage = &dev->states_usage[index];
808         struct acpi_processor_cx *cx = cpuidle_get_statedata(state_usage);
809         ktime_t  kt1, kt2;
810         s64 idle_time_ns;
811         s64 idle_time;
812
813         pr = __this_cpu_read(processors);
814         dev->last_residency = 0;
815
816         if (unlikely(!pr))
817                 return -EINVAL;
818
819         local_irq_disable();
820
821
822         if (cx->entry_method != ACPI_CSTATE_FFH) {
823                 current_thread_info()->status &= ~TS_POLLING;
824                 /*
825                  * TS_POLLING-cleared state must be visible before we test
826                  * NEED_RESCHED:
827                  */
828                 smp_mb();
829
830                 if (unlikely(need_resched())) {
831                         current_thread_info()->status |= TS_POLLING;
832                         local_irq_enable();
833                         return -EINVAL;
834                 }
835         }
836
837         /*
838          * Must be done before busmaster disable as we might need to
839          * access HPET !
840          */
841         lapic_timer_state_broadcast(pr, cx, 1);
842
843         if (cx->type == ACPI_STATE_C3)
844                 ACPI_FLUSH_CPU_CACHE();
845
846         kt1 = ktime_get_real();
847         /* Tell the scheduler that we are going deep-idle: */
848         sched_clock_idle_sleep_event();
849         acpi_idle_do_entry(cx);
850         kt2 = ktime_get_real();
851         idle_time_ns = ktime_to_ns(ktime_sub(kt2, kt1));
852         idle_time = idle_time_ns;
853         do_div(idle_time, NSEC_PER_USEC);
854
855         /* Update device last_residency*/
856         dev->last_residency = (int)idle_time;
857
858         /* Tell the scheduler how much we idled: */
859         sched_clock_idle_wakeup_event(idle_time_ns);
860
861         local_irq_enable();
862         if (cx->entry_method != ACPI_CSTATE_FFH)
863                 current_thread_info()->status |= TS_POLLING;
864
865         lapic_timer_state_broadcast(pr, cx, 0);
866         return index;
867 }
868
869 static int c3_cpu_count;
870 static DEFINE_RAW_SPINLOCK(c3_lock);
871
872 /**
873  * acpi_idle_enter_bm - enters C3 with proper BM handling
874  * @dev: the target CPU
875  * @drv: cpuidle driver containing state data
876  * @index: the index of suggested state
877  *
878  * If BM is detected, the deepest non-C3 idle state is entered instead.
879  */
880 static int acpi_idle_enter_bm(struct cpuidle_device *dev,
881                 struct cpuidle_driver *drv, int index)
882 {
883         struct acpi_processor *pr;
884         struct cpuidle_state_usage *state_usage = &dev->states_usage[index];
885         struct acpi_processor_cx *cx = cpuidle_get_statedata(state_usage);
886         ktime_t  kt1, kt2;
887         s64 idle_time_ns;
888         s64 idle_time;
889
890
891         pr = __this_cpu_read(processors);
892         dev->last_residency = 0;
893
894         if (unlikely(!pr))
895                 return -EINVAL;
896
897         if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
898                 if (drv->safe_state_index >= 0) {
899                         return drv->states[drv->safe_state_index].enter(dev,
900                                                 drv, drv->safe_state_index);
901                 } else {
902                         local_irq_disable();
903                         acpi_safe_halt();
904                         local_irq_enable();
905                         return -EBUSY;
906                 }
907         }
908
909         local_irq_disable();
910
911
912         if (cx->entry_method != ACPI_CSTATE_FFH) {
913                 current_thread_info()->status &= ~TS_POLLING;
914                 /*
915                  * TS_POLLING-cleared state must be visible before we test
916                  * NEED_RESCHED:
917                  */
918                 smp_mb();
919
920                 if (unlikely(need_resched())) {
921                         current_thread_info()->status |= TS_POLLING;
922                         local_irq_enable();
923                         return -EINVAL;
924                 }
925         }
926
927         acpi_unlazy_tlb(smp_processor_id());
928
929         /* Tell the scheduler that we are going deep-idle: */
930         sched_clock_idle_sleep_event();
931         /*
932          * Must be done before busmaster disable as we might need to
933          * access HPET !
934          */
935         lapic_timer_state_broadcast(pr, cx, 1);
936
937         kt1 = ktime_get_real();
938         /*
939          * disable bus master
940          * bm_check implies we need ARB_DIS
941          * !bm_check implies we need cache flush
942          * bm_control implies whether we can do ARB_DIS
943          *
944          * That leaves a case where bm_check is set and bm_control is
945          * not set. In that case we cannot do much, we enter C3
946          * without doing anything.
947          */
948         if (pr->flags.bm_check && pr->flags.bm_control) {
949                 raw_spin_lock(&c3_lock);
950                 c3_cpu_count++;
951                 /* Disable bus master arbitration when all CPUs are in C3 */
952                 if (c3_cpu_count == num_online_cpus())
953                         acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
954                 raw_spin_unlock(&c3_lock);
955         } else if (!pr->flags.bm_check) {
956                 ACPI_FLUSH_CPU_CACHE();
957         }
958
959         acpi_idle_do_entry(cx);
960
961         /* Re-enable bus master arbitration */
962         if (pr->flags.bm_check && pr->flags.bm_control) {
963                 raw_spin_lock(&c3_lock);
964                 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
965                 c3_cpu_count--;
966                 raw_spin_unlock(&c3_lock);
967         }
968         kt2 = ktime_get_real();
969         idle_time_ns = ktime_to_ns(ktime_sub(kt2, kt1));
970         idle_time = idle_time_ns;
971         do_div(idle_time, NSEC_PER_USEC);
972
973         /* Update device last_residency*/
974         dev->last_residency = (int)idle_time;
975
976         /* Tell the scheduler how much we idled: */
977         sched_clock_idle_wakeup_event(idle_time_ns);
978
979         local_irq_enable();
980         if (cx->entry_method != ACPI_CSTATE_FFH)
981                 current_thread_info()->status |= TS_POLLING;
982
983         lapic_timer_state_broadcast(pr, cx, 0);
984         return index;
985 }
986
987 struct cpuidle_driver acpi_idle_driver = {
988         .name =         "acpi_idle",
989         .owner =        THIS_MODULE,
990 };
991
992 /**
993  * acpi_processor_setup_cpuidle_cx - prepares and configures CPUIDLE
994  * device i.e. per-cpu data
995  *
996  * @pr: the ACPI processor
997  */
998 static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr)
999 {
1000         int i, count = CPUIDLE_DRIVER_STATE_START;
1001         struct acpi_processor_cx *cx;
1002         struct cpuidle_state_usage *state_usage;
1003         struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);
1004
1005         if (!pr->flags.power_setup_done)
1006                 return -EINVAL;
1007
1008         if (pr->flags.power == 0) {
1009                 return -EINVAL;
1010         }
1011
1012         if (!dev)
1013                 return -EINVAL;
1014
1015         dev->cpu = pr->id;
1016
1017         if (max_cstate == 0)
1018                 max_cstate = 1;
1019
1020         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
1021                 cx = &pr->power.states[i];
1022                 state_usage = &dev->states_usage[count];
1023
1024                 if (!cx->valid)
1025                         continue;
1026
1027 #ifdef CONFIG_HOTPLUG_CPU
1028                 if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
1029                     !pr->flags.has_cst &&
1030                     !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
1031                         continue;
1032 #endif
1033
1034                 cpuidle_set_statedata(state_usage, cx);
1035
1036                 count++;
1037                 if (count == CPUIDLE_STATE_MAX)
1038                         break;
1039         }
1040
1041         dev->state_count = count;
1042
1043         if (!count)
1044                 return -EINVAL;
1045
1046         return 0;
1047 }
1048
1049 /**
1050  * acpi_processor_setup_cpuidle states- prepares and configures cpuidle
1051  * global state data i.e. idle routines
1052  *
1053  * @pr: the ACPI processor
1054  */
1055 static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
1056 {
1057         int i, count = CPUIDLE_DRIVER_STATE_START;
1058         struct acpi_processor_cx *cx;
1059         struct cpuidle_state *state;
1060         struct cpuidle_driver *drv = &acpi_idle_driver;
1061
1062         if (!pr->flags.power_setup_done)
1063                 return -EINVAL;
1064
1065         if (pr->flags.power == 0)
1066                 return -EINVAL;
1067
1068         drv->safe_state_index = -1;
1069         for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
1070                 drv->states[i].name[0] = '\0';
1071                 drv->states[i].desc[0] = '\0';
1072         }
1073
1074         if (max_cstate == 0)
1075                 max_cstate = 1;
1076
1077         for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
1078                 cx = &pr->power.states[i];
1079
1080                 if (!cx->valid)
1081                         continue;
1082
1083 #ifdef CONFIG_HOTPLUG_CPU
1084                 if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
1085                     !pr->flags.has_cst &&
1086                     !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
1087                         continue;
1088 #endif
1089
1090                 state = &drv->states[count];
1091                 snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);
1092                 strncpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);
1093                 state->exit_latency = cx->latency;
1094                 state->target_residency = cx->latency * latency_factor;
1095
1096                 state->flags = 0;
1097                 switch (cx->type) {
1098                         case ACPI_STATE_C1:
1099                         if (cx->entry_method == ACPI_CSTATE_FFH)
1100                                 state->flags |= CPUIDLE_FLAG_TIME_VALID;
1101
1102                         state->enter = acpi_idle_enter_c1;
1103                         state->enter_dead = acpi_idle_play_dead;
1104                         drv->safe_state_index = count;
1105                         break;
1106
1107                         case ACPI_STATE_C2:
1108                         state->flags |= CPUIDLE_FLAG_TIME_VALID;
1109                         state->enter = acpi_idle_enter_simple;
1110                         state->enter_dead = acpi_idle_play_dead;
1111                         drv->safe_state_index = count;
1112                         break;
1113
1114                         case ACPI_STATE_C3:
1115                         state->flags |= CPUIDLE_FLAG_TIME_VALID;
1116                         state->enter = pr->flags.bm_check ?
1117                                         acpi_idle_enter_bm :
1118                                         acpi_idle_enter_simple;
1119                         break;
1120                 }
1121
1122                 count++;
1123                 if (count == CPUIDLE_STATE_MAX)
1124                         break;
1125         }
1126
1127         drv->state_count = count;
1128
1129         if (!count)
1130                 return -EINVAL;
1131
1132         return 0;
1133 }
1134
1135 int acpi_processor_hotplug(struct acpi_processor *pr)
1136 {
1137         int ret = 0;
1138         struct cpuidle_device *dev;
1139
1140         if (disabled_by_idle_boot_param())
1141                 return 0;
1142
1143         if (!pr)
1144                 return -EINVAL;
1145
1146         if (nocst) {
1147                 return -ENODEV;
1148         }
1149
1150         if (!pr->flags.power_setup_done)
1151                 return -ENODEV;
1152
1153         dev = per_cpu(acpi_cpuidle_device, pr->id);
1154         cpuidle_pause_and_lock();
1155         cpuidle_disable_device(dev);
1156         acpi_processor_get_power_info(pr);
1157         if (pr->flags.power) {
1158                 acpi_processor_setup_cpuidle_cx(pr);
1159                 ret = cpuidle_enable_device(dev);
1160         }
1161         cpuidle_resume_and_unlock();
1162
1163         return ret;
1164 }
1165
1166 int acpi_processor_cst_has_changed(struct acpi_processor *pr)
1167 {
1168         int cpu;
1169         struct acpi_processor *_pr;
1170         struct cpuidle_device *dev;
1171
1172         if (disabled_by_idle_boot_param())
1173                 return 0;
1174
1175         if (!pr)
1176                 return -EINVAL;
1177
1178         if (nocst)
1179                 return -ENODEV;
1180
1181         if (!pr->flags.power_setup_done)
1182                 return -ENODEV;
1183
1184         /*
1185          * FIXME:  Design the ACPI notification to make it once per
1186          * system instead of once per-cpu.  This condition is a hack
1187          * to make the code that updates C-States be called once.
1188          */
1189
1190         if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {
1191
1192                 cpuidle_pause_and_lock();
1193                 /* Protect against cpu-hotplug */
1194                 get_online_cpus();
1195
1196                 /* Disable all cpuidle devices */
1197                 for_each_online_cpu(cpu) {
1198                         _pr = per_cpu(processors, cpu);
1199                         if (!_pr || !_pr->flags.power_setup_done)
1200                                 continue;
1201                         dev = per_cpu(acpi_cpuidle_device, cpu);
1202                         cpuidle_disable_device(dev);
1203                 }
1204
1205                 /* Populate Updated C-state information */
1206                 acpi_processor_setup_cpuidle_states(pr);
1207
1208                 /* Enable all cpuidle devices */
1209                 for_each_online_cpu(cpu) {
1210                         _pr = per_cpu(processors, cpu);
1211                         if (!_pr || !_pr->flags.power_setup_done)
1212                                 continue;
1213                         acpi_processor_get_power_info(_pr);
1214                         if (_pr->flags.power) {
1215                                 acpi_processor_setup_cpuidle_cx(_pr);
1216                                 dev = per_cpu(acpi_cpuidle_device, cpu);
1217                                 cpuidle_enable_device(dev);
1218                         }
1219                 }
1220                 put_online_cpus();
1221                 cpuidle_resume_and_unlock();
1222         }
1223
1224         return 0;
1225 }
1226
1227 static int acpi_processor_registered;
1228
1229 int __cpuinit acpi_processor_power_init(struct acpi_processor *pr)
1230 {
1231         acpi_status status = 0;
1232         int retval;
1233         struct cpuidle_device *dev;
1234         static int first_run;
1235
1236         if (disabled_by_idle_boot_param())
1237                 return 0;
1238
1239         if (!first_run) {
1240                 dmi_check_system(processor_power_dmi_table);
1241                 max_cstate = acpi_processor_cstate_check(max_cstate);
1242                 if (max_cstate < ACPI_C_STATES_MAX)
1243                         printk(KERN_NOTICE
1244                                "ACPI: processor limited to max C-state %d\n",
1245                                max_cstate);
1246                 first_run++;
1247         }
1248
1249         if (!pr)
1250                 return -EINVAL;
1251
1252         if (acpi_gbl_FADT.cst_control && !nocst) {
1253                 status =
1254                     acpi_os_write_port(acpi_gbl_FADT.smi_command, acpi_gbl_FADT.cst_control, 8);
1255                 if (ACPI_FAILURE(status)) {
1256                         ACPI_EXCEPTION((AE_INFO, status,
1257                                         "Notifying BIOS of _CST ability failed"));
1258                 }
1259         }
1260
1261         acpi_processor_get_power_info(pr);
1262         pr->flags.power_setup_done = 1;
1263
1264         /*
1265          * Install the idle handler if processor power management is supported.
1266          * Note that we use previously set idle handler will be used on
1267          * platforms that only support C1.
1268          */
1269         if (pr->flags.power) {
1270                 /* Register acpi_idle_driver if not already registered */
1271                 if (!acpi_processor_registered) {
1272                         acpi_processor_setup_cpuidle_states(pr);
1273                         retval = cpuidle_register_driver(&acpi_idle_driver);
1274                         if (retval)
1275                                 return retval;
1276                         printk(KERN_DEBUG "ACPI: %s registered with cpuidle\n",
1277                                         acpi_idle_driver.name);
1278                 }
1279
1280                 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1281                 if (!dev)
1282                         return -ENOMEM;
1283                 per_cpu(acpi_cpuidle_device, pr->id) = dev;
1284
1285                 acpi_processor_setup_cpuidle_cx(pr);
1286
1287                 /* Register per-cpu cpuidle_device. Cpuidle driver
1288                  * must already be registered before registering device
1289                  */
1290                 retval = cpuidle_register_device(dev);
1291                 if (retval) {
1292                         if (acpi_processor_registered == 0)
1293                                 cpuidle_unregister_driver(&acpi_idle_driver);
1294                         return retval;
1295                 }
1296                 acpi_processor_registered++;
1297         }
1298         return 0;
1299 }
1300
1301 int acpi_processor_power_exit(struct acpi_processor *pr)
1302 {
1303         struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);
1304
1305         if (disabled_by_idle_boot_param())
1306                 return 0;
1307
1308         if (pr->flags.power) {
1309                 cpuidle_unregister_device(dev);
1310                 acpi_processor_registered--;
1311                 if (acpi_processor_registered == 0)
1312                         cpuidle_unregister_driver(&acpi_idle_driver);
1313         }
1314
1315         pr->flags.power_setup_done = 0;
1316         return 0;
1317 }