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 */