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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * acpi_processor.c - ACPI processor enumeration support
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 Dominik Brodowski <linux@brodo.de>
8 * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
9 * Copyright (C) 2013, Intel Corporation
10 * Rafael J. Wysocki <rafael.j.wysocki@intel.com>
11 */
12
13#include <linux/acpi.h>
14#include <linux/device.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/pci.h>
18
19#include <acpi/processor.h>
20
21#include <asm/cpu.h>
22
23#include "internal.h"
24
25#define _COMPONENT ACPI_PROCESSOR_COMPONENT
26
27ACPI_MODULE_NAME("processor");
28
29DEFINE_PER_CPU(struct acpi_processor *, processors);
30EXPORT_PER_CPU_SYMBOL(processors);
31
32/* --------------------------------------------------------------------------
33 Errata Handling
34 -------------------------------------------------------------------------- */
35
36struct acpi_processor_errata errata __read_mostly;
37EXPORT_SYMBOL_GPL(errata);
38
39static int acpi_processor_errata_piix4(struct pci_dev *dev)
40{
41 u8 value1 = 0;
42 u8 value2 = 0;
43
44
45 if (!dev)
46 return -EINVAL;
47
48 /*
49 * Note that 'dev' references the PIIX4 ACPI Controller.
50 */
51
52 switch (dev->revision) {
53 case 0:
54 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 A-step\n"));
55 break;
56 case 1:
57 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 B-step\n"));
58 break;
59 case 2:
60 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4E\n"));
61 break;
62 case 3:
63 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4M\n"));
64 break;
65 default:
66 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found unknown PIIX4\n"));
67 break;
68 }
69
70 switch (dev->revision) {
71
72 case 0: /* PIIX4 A-step */
73 case 1: /* PIIX4 B-step */
74 /*
75 * See specification changes #13 ("Manual Throttle Duty Cycle")
76 * and #14 ("Enabling and Disabling Manual Throttle"), plus
77 * erratum #5 ("STPCLK# Deassertion Time") from the January
78 * 2002 PIIX4 specification update. Applies to only older
79 * PIIX4 models.
80 */
81 errata.piix4.throttle = 1;
82 fallthrough;
83
84 case 2: /* PIIX4E */
85 case 3: /* PIIX4M */
86 /*
87 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
88 * Livelock") from the January 2002 PIIX4 specification update.
89 * Applies to all PIIX4 models.
90 */
91
92 /*
93 * BM-IDE
94 * ------
95 * Find the PIIX4 IDE Controller and get the Bus Master IDE
96 * Status register address. We'll use this later to read
97 * each IDE controller's DMA status to make sure we catch all
98 * DMA activity.
99 */
100 dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
101 PCI_DEVICE_ID_INTEL_82371AB,
102 PCI_ANY_ID, PCI_ANY_ID, NULL);
103 if (dev) {
104 errata.piix4.bmisx = pci_resource_start(dev, 4);
105 pci_dev_put(dev);
106 }
107
108 /*
109 * Type-F DMA
110 * ----------
111 * Find the PIIX4 ISA Controller and read the Motherboard
112 * DMA controller's status to see if Type-F (Fast) DMA mode
113 * is enabled (bit 7) on either channel. Note that we'll
114 * disable C3 support if this is enabled, as some legacy
115 * devices won't operate well if fast DMA is disabled.
116 */
117 dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
118 PCI_DEVICE_ID_INTEL_82371AB_0,
119 PCI_ANY_ID, PCI_ANY_ID, NULL);
120 if (dev) {
121 pci_read_config_byte(dev, 0x76, &value1);
122 pci_read_config_byte(dev, 0x77, &value2);
123 if ((value1 & 0x80) || (value2 & 0x80))
124 errata.piix4.fdma = 1;
125 pci_dev_put(dev);
126 }
127
128 break;
129 }
130
131 if (errata.piix4.bmisx)
132 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
133 "Bus master activity detection (BM-IDE) erratum enabled\n"));
134 if (errata.piix4.fdma)
135 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
136 "Type-F DMA livelock erratum (C3 disabled)\n"));
137
138 return 0;
139}
140
141static int acpi_processor_errata(void)
142{
143 int result = 0;
144 struct pci_dev *dev = NULL;
145
146 /*
147 * PIIX4
148 */
149 dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
150 PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
151 PCI_ANY_ID, NULL);
152 if (dev) {
153 result = acpi_processor_errata_piix4(dev);
154 pci_dev_put(dev);
155 }
156
157 return result;
158}
159
160/* --------------------------------------------------------------------------
161 Initialization
162 -------------------------------------------------------------------------- */
163
164#ifdef CONFIG_ACPI_HOTPLUG_CPU
165int __weak acpi_map_cpu(acpi_handle handle,
166 phys_cpuid_t physid, u32 acpi_id, int *pcpu)
167{
168 return -ENODEV;
169}
170
171int __weak acpi_unmap_cpu(int cpu)
172{
173 return -ENODEV;
174}
175
176int __weak arch_register_cpu(int cpu)
177{
178 return -ENODEV;
179}
180
181void __weak arch_unregister_cpu(int cpu) {}
182
183static int acpi_processor_hotadd_init(struct acpi_processor *pr)
184{
185 unsigned long long sta;
186 acpi_status status;
187 int ret;
188
189 if (invalid_phys_cpuid(pr->phys_id))
190 return -ENODEV;
191
192 status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
193 if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
194 return -ENODEV;
195
196 cpu_maps_update_begin();
197 cpu_hotplug_begin();
198
199 ret = acpi_map_cpu(pr->handle, pr->phys_id, pr->acpi_id, &pr->id);
200 if (ret)
201 goto out;
202
203 ret = arch_register_cpu(pr->id);
204 if (ret) {
205 acpi_unmap_cpu(pr->id);
206 goto out;
207 }
208
209 /*
210 * CPU got hot-added, but cpu_data is not initialized yet. Set a flag
211 * to delay cpu_idle/throttling initialization and do it when the CPU
212 * gets online for the first time.
213 */
214 pr_info("CPU%d has been hot-added\n", pr->id);
215 pr->flags.need_hotplug_init = 1;
216
217out:
218 cpu_hotplug_done();
219 cpu_maps_update_done();
220 return ret;
221}
222#else
223static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
224{
225 return -ENODEV;
226}
227#endif /* CONFIG_ACPI_HOTPLUG_CPU */
228
229static int acpi_processor_get_info(struct acpi_device *device)
230{
231 union acpi_object object = { 0 };
232 struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
233 struct acpi_processor *pr = acpi_driver_data(device);
234 int device_declaration = 0;
235 acpi_status status = AE_OK;
236 static int cpu0_initialized;
237 unsigned long long value;
238
239 acpi_processor_errata();
240
241 /*
242 * Check to see if we have bus mastering arbitration control. This
243 * is required for proper C3 usage (to maintain cache coherency).
244 */
245 if (acpi_gbl_FADT.pm2_control_block && acpi_gbl_FADT.pm2_control_length) {
246 pr->flags.bm_control = 1;
247 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
248 "Bus mastering arbitration control present\n"));
249 } else
250 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
251 "No bus mastering arbitration control\n"));
252
253 if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
254 /* Declared with "Processor" statement; match ProcessorID */
255 status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
256 if (ACPI_FAILURE(status)) {
257 dev_err(&device->dev,
258 "Failed to evaluate processor object (0x%x)\n",
259 status);
260 return -ENODEV;
261 }
262
263 pr->acpi_id = object.processor.proc_id;
264 } else {
265 /*
266 * Declared with "Device" statement; match _UID.
267 * Note that we don't handle string _UIDs yet.
268 */
269 status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
270 NULL, &value);
271 if (ACPI_FAILURE(status)) {
272 dev_err(&device->dev,
273 "Failed to evaluate processor _UID (0x%x)\n",
274 status);
275 return -ENODEV;
276 }
277 device_declaration = 1;
278 pr->acpi_id = value;
279 }
280
281 if (acpi_duplicate_processor_id(pr->acpi_id)) {
282 if (pr->acpi_id == 0xff)
283 dev_info_once(&device->dev,
284 "Entry not well-defined, consider updating BIOS\n");
285 else
286 dev_err(&device->dev,
287 "Failed to get unique processor _UID (0x%x)\n",
288 pr->acpi_id);
289 return -ENODEV;
290 }
291
292 pr->phys_id = acpi_get_phys_id(pr->handle, device_declaration,
293 pr->acpi_id);
294 if (invalid_phys_cpuid(pr->phys_id))
295 acpi_handle_debug(pr->handle, "failed to get CPU physical ID.\n");
296
297 pr->id = acpi_map_cpuid(pr->phys_id, pr->acpi_id);
298 if (!cpu0_initialized && !acpi_has_cpu_in_madt()) {
299 cpu0_initialized = 1;
300 /*
301 * Handle UP system running SMP kernel, with no CPU
302 * entry in MADT
303 */
304 if (invalid_logical_cpuid(pr->id) && (num_online_cpus() == 1))
305 pr->id = 0;
306 }
307
308 /*
309 * Extra Processor objects may be enumerated on MP systems with
310 * less than the max # of CPUs. They should be ignored _iff
311 * they are physically not present.
312 *
313 * NOTE: Even if the processor has a cpuid, it may not be present
314 * because cpuid <-> apicid mapping is persistent now.
315 */
316 if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id)) {
317 int ret = acpi_processor_hotadd_init(pr);
318 if (ret)
319 return ret;
320 }
321
322 /*
323 * On some boxes several processors use the same processor bus id.
324 * But they are located in different scope. For example:
325 * \_SB.SCK0.CPU0
326 * \_SB.SCK1.CPU0
327 * Rename the processor device bus id. And the new bus id will be
328 * generated as the following format:
329 * CPU+CPU ID.
330 */
331 sprintf(acpi_device_bid(device), "CPU%X", pr->id);
332 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d:%d]\n", pr->id,
333 pr->acpi_id));
334
335 if (!object.processor.pblk_address)
336 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No PBLK (NULL address)\n"));
337 else if (object.processor.pblk_length != 6)
338 dev_err(&device->dev, "Invalid PBLK length [%d]\n",
339 object.processor.pblk_length);
340 else {
341 pr->throttling.address = object.processor.pblk_address;
342 pr->throttling.duty_offset = acpi_gbl_FADT.duty_offset;
343 pr->throttling.duty_width = acpi_gbl_FADT.duty_width;
344
345 pr->pblk = object.processor.pblk_address;
346 }
347
348 /*
349 * If ACPI describes a slot number for this CPU, we can use it to
350 * ensure we get the right value in the "physical id" field
351 * of /proc/cpuinfo
352 */
353 status = acpi_evaluate_integer(pr->handle, "_SUN", NULL, &value);
354 if (ACPI_SUCCESS(status))
355 arch_fix_phys_package_id(pr->id, value);
356
357 return 0;
358}
359
360/*
361 * Do not put anything in here which needs the core to be online.
362 * For example MSR access or setting up things which check for cpuinfo_x86
363 * (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
364 * Such things have to be put in and set up by the processor driver's .probe().
365 */
366static DEFINE_PER_CPU(void *, processor_device_array);
367
368static int acpi_processor_add(struct acpi_device *device,
369 const struct acpi_device_id *id)
370{
371 struct acpi_processor *pr;
372 struct device *dev;
373 int result = 0;
374
375 pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
376 if (!pr)
377 return -ENOMEM;
378
379 if (!zalloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
380 result = -ENOMEM;
381 goto err_free_pr;
382 }
383
384 pr->handle = device->handle;
385 strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
386 strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
387 device->driver_data = pr;
388
389 result = acpi_processor_get_info(device);
390 if (result) /* Processor is not physically present or unavailable */
391 return 0;
392
393 BUG_ON(pr->id >= nr_cpu_ids);
394
395 /*
396 * Buggy BIOS check.
397 * ACPI id of processors can be reported wrongly by the BIOS.
398 * Don't trust it blindly
399 */
400 if (per_cpu(processor_device_array, pr->id) != NULL &&
401 per_cpu(processor_device_array, pr->id) != device) {
402 dev_warn(&device->dev,
403 "BIOS reported wrong ACPI id %d for the processor\n",
404 pr->id);
405 /* Give up, but do not abort the namespace scan. */
406 goto err;
407 }
408 /*
409 * processor_device_array is not cleared on errors to allow buggy BIOS
410 * checks.
411 */
412 per_cpu(processor_device_array, pr->id) = device;
413 per_cpu(processors, pr->id) = pr;
414
415 dev = get_cpu_device(pr->id);
416 if (!dev) {
417 result = -ENODEV;
418 goto err;
419 }
420
421 result = acpi_bind_one(dev, device);
422 if (result)
423 goto err;
424
425 pr->dev = dev;
426
427 /* Trigger the processor driver's .probe() if present. */
428 if (device_attach(dev) >= 0)
429 return 1;
430
431 dev_err(dev, "Processor driver could not be attached\n");
432 acpi_unbind_one(dev);
433
434 err:
435 free_cpumask_var(pr->throttling.shared_cpu_map);
436 device->driver_data = NULL;
437 per_cpu(processors, pr->id) = NULL;
438 err_free_pr:
439 kfree(pr);
440 return result;
441}
442
443#ifdef CONFIG_ACPI_HOTPLUG_CPU
444/* --------------------------------------------------------------------------
445 Removal
446 -------------------------------------------------------------------------- */
447
448static void acpi_processor_remove(struct acpi_device *device)
449{
450 struct acpi_processor *pr;
451
452 if (!device || !acpi_driver_data(device))
453 return;
454
455 pr = acpi_driver_data(device);
456 if (pr->id >= nr_cpu_ids)
457 goto out;
458
459 /*
460 * The only reason why we ever get here is CPU hot-removal. The CPU is
461 * already offline and the ACPI device removal locking prevents it from
462 * being put back online at this point.
463 *
464 * Unbind the driver from the processor device and detach it from the
465 * ACPI companion object.
466 */
467 device_release_driver(pr->dev);
468 acpi_unbind_one(pr->dev);
469
470 /* Clean up. */
471 per_cpu(processor_device_array, pr->id) = NULL;
472 per_cpu(processors, pr->id) = NULL;
473
474 cpu_maps_update_begin();
475 cpu_hotplug_begin();
476
477 /* Remove the CPU. */
478 arch_unregister_cpu(pr->id);
479 acpi_unmap_cpu(pr->id);
480
481 cpu_hotplug_done();
482 cpu_maps_update_done();
483
484 try_offline_node(cpu_to_node(pr->id));
485
486 out:
487 free_cpumask_var(pr->throttling.shared_cpu_map);
488 kfree(pr);
489}
490#endif /* CONFIG_ACPI_HOTPLUG_CPU */
491
492#ifdef CONFIG_X86
493static bool acpi_hwp_native_thermal_lvt_set;
494static acpi_status __init acpi_hwp_native_thermal_lvt_osc(acpi_handle handle,
495 u32 lvl,
496 void *context,
497 void **rv)
498{
499 u8 sb_uuid_str[] = "4077A616-290C-47BE-9EBD-D87058713953";
500 u32 capbuf[2];
501 struct acpi_osc_context osc_context = {
502 .uuid_str = sb_uuid_str,
503 .rev = 1,
504 .cap.length = 8,
505 .cap.pointer = capbuf,
506 };
507
508 if (acpi_hwp_native_thermal_lvt_set)
509 return AE_CTRL_TERMINATE;
510
511 capbuf[0] = 0x0000;
512 capbuf[1] = 0x1000; /* set bit 12 */
513
514 if (ACPI_SUCCESS(acpi_run_osc(handle, &osc_context))) {
515 if (osc_context.ret.pointer && osc_context.ret.length > 1) {
516 u32 *capbuf_ret = osc_context.ret.pointer;
517
518 if (capbuf_ret[1] & 0x1000) {
519 acpi_handle_info(handle,
520 "_OSC native thermal LVT Acked\n");
521 acpi_hwp_native_thermal_lvt_set = true;
522 }
523 }
524 kfree(osc_context.ret.pointer);
525 }
526
527 return AE_OK;
528}
529
530void __init acpi_early_processor_osc(void)
531{
532 if (boot_cpu_has(X86_FEATURE_HWP)) {
533 acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
534 ACPI_UINT32_MAX,
535 acpi_hwp_native_thermal_lvt_osc,
536 NULL, NULL, NULL);
537 acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID,
538 acpi_hwp_native_thermal_lvt_osc,
539 NULL, NULL);
540 }
541}
542#endif
543
544/*
545 * The following ACPI IDs are known to be suitable for representing as
546 * processor devices.
547 */
548static const struct acpi_device_id processor_device_ids[] = {
549
550 { ACPI_PROCESSOR_OBJECT_HID, },
551 { ACPI_PROCESSOR_DEVICE_HID, },
552
553 { }
554};
555
556static struct acpi_scan_handler processor_handler = {
557 .ids = processor_device_ids,
558 .attach = acpi_processor_add,
559#ifdef CONFIG_ACPI_HOTPLUG_CPU
560 .detach = acpi_processor_remove,
561#endif
562 .hotplug = {
563 .enabled = true,
564 },
565};
566
567static int acpi_processor_container_attach(struct acpi_device *dev,
568 const struct acpi_device_id *id)
569{
570 return 1;
571}
572
573static const struct acpi_device_id processor_container_ids[] = {
574 { ACPI_PROCESSOR_CONTAINER_HID, },
575 { }
576};
577
578static struct acpi_scan_handler processor_container_handler = {
579 .ids = processor_container_ids,
580 .attach = acpi_processor_container_attach,
581};
582
583/* The number of the unique processor IDs */
584static int nr_unique_ids __initdata;
585
586/* The number of the duplicate processor IDs */
587static int nr_duplicate_ids;
588
589/* Used to store the unique processor IDs */
590static int unique_processor_ids[] __initdata = {
591 [0 ... NR_CPUS - 1] = -1,
592};
593
594/* Used to store the duplicate processor IDs */
595static int duplicate_processor_ids[] = {
596 [0 ... NR_CPUS - 1] = -1,
597};
598
599static void __init processor_validated_ids_update(int proc_id)
600{
601 int i;
602
603 if (nr_unique_ids == NR_CPUS||nr_duplicate_ids == NR_CPUS)
604 return;
605
606 /*
607 * Firstly, compare the proc_id with duplicate IDs, if the proc_id is
608 * already in the IDs, do nothing.
609 */
610 for (i = 0; i < nr_duplicate_ids; i++) {
611 if (duplicate_processor_ids[i] == proc_id)
612 return;
613 }
614
615 /*
616 * Secondly, compare the proc_id with unique IDs, if the proc_id is in
617 * the IDs, put it in the duplicate IDs.
618 */
619 for (i = 0; i < nr_unique_ids; i++) {
620 if (unique_processor_ids[i] == proc_id) {
621 duplicate_processor_ids[nr_duplicate_ids] = proc_id;
622 nr_duplicate_ids++;
623 return;
624 }
625 }
626
627 /*
628 * Lastly, the proc_id is a unique ID, put it in the unique IDs.
629 */
630 unique_processor_ids[nr_unique_ids] = proc_id;
631 nr_unique_ids++;
632}
633
634static acpi_status __init acpi_processor_ids_walk(acpi_handle handle,
635 u32 lvl,
636 void *context,
637 void **rv)
638{
639 acpi_status status;
640 acpi_object_type acpi_type;
641 unsigned long long uid;
642 union acpi_object object = { 0 };
643 struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
644
645 status = acpi_get_type(handle, &acpi_type);
646 if (ACPI_FAILURE(status))
647 return status;
648
649 switch (acpi_type) {
650 case ACPI_TYPE_PROCESSOR:
651 status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
652 if (ACPI_FAILURE(status))
653 goto err;
654 uid = object.processor.proc_id;
655 break;
656
657 case ACPI_TYPE_DEVICE:
658 status = acpi_evaluate_integer(handle, "_UID", NULL, &uid);
659 if (ACPI_FAILURE(status))
660 goto err;
661 break;
662 default:
663 goto err;
664 }
665
666 processor_validated_ids_update(uid);
667 return AE_OK;
668
669err:
670 /* Exit on error, but don't abort the namespace walk */
671 acpi_handle_info(handle, "Invalid processor object\n");
672 return AE_OK;
673
674}
675
676static void __init acpi_processor_check_duplicates(void)
677{
678 /* check the correctness for all processors in ACPI namespace */
679 acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
680 ACPI_UINT32_MAX,
681 acpi_processor_ids_walk,
682 NULL, NULL, NULL);
683 acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, acpi_processor_ids_walk,
684 NULL, NULL);
685}
686
687bool acpi_duplicate_processor_id(int proc_id)
688{
689 int i;
690
691 /*
692 * compare the proc_id with duplicate IDs, if the proc_id is already
693 * in the duplicate IDs, return true, otherwise, return false.
694 */
695 for (i = 0; i < nr_duplicate_ids; i++) {
696 if (duplicate_processor_ids[i] == proc_id)
697 return true;
698 }
699 return false;
700}
701
702void __init acpi_processor_init(void)
703{
704 acpi_processor_check_duplicates();
705 acpi_scan_add_handler_with_hotplug(&processor_handler, "processor");
706 acpi_scan_add_handler(&processor_container_handler);
707}
708
709#ifdef CONFIG_ACPI_PROCESSOR_CSTATE
710/**
711 * acpi_processor_claim_cst_control - Request _CST control from the platform.
712 */
713bool acpi_processor_claim_cst_control(void)
714{
715 static bool cst_control_claimed;
716 acpi_status status;
717
718 if (!acpi_gbl_FADT.cst_control || cst_control_claimed)
719 return true;
720
721 status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
722 acpi_gbl_FADT.cst_control, 8);
723 if (ACPI_FAILURE(status)) {
724 pr_warn("ACPI: Failed to claim processor _CST control\n");
725 return false;
726 }
727
728 cst_control_claimed = true;
729 return true;
730}
731EXPORT_SYMBOL_GPL(acpi_processor_claim_cst_control);
732
733/**
734 * acpi_processor_evaluate_cst - Evaluate the processor _CST control method.
735 * @handle: ACPI handle of the processor object containing the _CST.
736 * @cpu: The numeric ID of the target CPU.
737 * @info: Object write the C-states information into.
738 *
739 * Extract the C-state information for the given CPU from the output of the _CST
740 * control method under the corresponding ACPI processor object (or processor
741 * device object) and populate @info with it.
742 *
743 * If any ACPI_ADR_SPACE_FIXED_HARDWARE C-states are found, invoke
744 * acpi_processor_ffh_cstate_probe() to verify them and update the
745 * cpu_cstate_entry data for @cpu.
746 */
747int acpi_processor_evaluate_cst(acpi_handle handle, u32 cpu,
748 struct acpi_processor_power *info)
749{
750 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
751 union acpi_object *cst;
752 acpi_status status;
753 u64 count;
754 int last_index = 0;
755 int i, ret = 0;
756
757 status = acpi_evaluate_object(handle, "_CST", NULL, &buffer);
758 if (ACPI_FAILURE(status)) {
759 acpi_handle_debug(handle, "No _CST\n");
760 return -ENODEV;
761 }
762
763 cst = buffer.pointer;
764
765 /* There must be at least 2 elements. */
766 if (!cst || cst->type != ACPI_TYPE_PACKAGE || cst->package.count < 2) {
767 acpi_handle_warn(handle, "Invalid _CST output\n");
768 ret = -EFAULT;
769 goto end;
770 }
771
772 count = cst->package.elements[0].integer.value;
773
774 /* Validate the number of C-states. */
775 if (count < 1 || count != cst->package.count - 1) {
776 acpi_handle_warn(handle, "Inconsistent _CST data\n");
777 ret = -EFAULT;
778 goto end;
779 }
780
781 for (i = 1; i <= count; i++) {
782 union acpi_object *element;
783 union acpi_object *obj;
784 struct acpi_power_register *reg;
785 struct acpi_processor_cx cx;
786
787 /*
788 * If there is not enough space for all C-states, skip the
789 * excess ones and log a warning.
790 */
791 if (last_index >= ACPI_PROCESSOR_MAX_POWER - 1) {
792 acpi_handle_warn(handle,
793 "No room for more idle states (limit: %d)\n",
794 ACPI_PROCESSOR_MAX_POWER - 1);
795 break;
796 }
797
798 memset(&cx, 0, sizeof(cx));
799
800 element = &cst->package.elements[i];
801 if (element->type != ACPI_TYPE_PACKAGE)
802 continue;
803
804 if (element->package.count != 4)
805 continue;
806
807 obj = &element->package.elements[0];
808
809 if (obj->type != ACPI_TYPE_BUFFER)
810 continue;
811
812 reg = (struct acpi_power_register *)obj->buffer.pointer;
813
814 obj = &element->package.elements[1];
815 if (obj->type != ACPI_TYPE_INTEGER)
816 continue;
817
818 cx.type = obj->integer.value;
819 /*
820 * There are known cases in which the _CST output does not
821 * contain C1, so if the type of the first state found is not
822 * C1, leave an empty slot for C1 to be filled in later.
823 */
824 if (i == 1 && cx.type != ACPI_STATE_C1)
825 last_index = 1;
826
827 cx.address = reg->address;
828 cx.index = last_index + 1;
829
830 if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
831 if (!acpi_processor_ffh_cstate_probe(cpu, &cx, reg)) {
832 /*
833 * In the majority of cases _CST describes C1 as
834 * a FIXED_HARDWARE C-state, but if the command
835 * line forbids using MWAIT, use CSTATE_HALT for
836 * C1 regardless.
837 */
838 if (cx.type == ACPI_STATE_C1 &&
839 boot_option_idle_override == IDLE_NOMWAIT) {
840 cx.entry_method = ACPI_CSTATE_HALT;
841 snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
842 } else {
843 cx.entry_method = ACPI_CSTATE_FFH;
844 }
845 } else if (cx.type == ACPI_STATE_C1) {
846 /*
847 * In the special case of C1, FIXED_HARDWARE can
848 * be handled by executing the HLT instruction.
849 */
850 cx.entry_method = ACPI_CSTATE_HALT;
851 snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
852 } else {
853 continue;
854 }
855 } else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
856 cx.entry_method = ACPI_CSTATE_SYSTEMIO;
857 snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
858 cx.address);
859 } else {
860 continue;
861 }
862
863 if (cx.type == ACPI_STATE_C1)
864 cx.valid = 1;
865
866 obj = &element->package.elements[2];
867 if (obj->type != ACPI_TYPE_INTEGER)
868 continue;
869
870 cx.latency = obj->integer.value;
871
872 obj = &element->package.elements[3];
873 if (obj->type != ACPI_TYPE_INTEGER)
874 continue;
875
876 memcpy(&info->states[++last_index], &cx, sizeof(cx));
877 }
878
879 acpi_handle_info(handle, "Found %d idle states\n", last_index);
880
881 info->count = last_index;
882
883 end:
884 kfree(buffer.pointer);
885
886 return ret;
887}
888EXPORT_SYMBOL_GPL(acpi_processor_evaluate_cst);
889#endif /* CONFIG_ACPI_PROCESSOR_CSTATE */