// SPDX-License-Identifier: GPL-2.0-only

  /*
   * acpi_processor.c - ACPI processor enumeration support
   *
   * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   * Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
   * Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   * Copyright (C) 2013, Intel Corporation
   *                     Rafael J. Wysocki <rafael.j.wysocki@intel.com>

   */
  
  #include <linux/acpi.h>
  #include <linux/device.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/pci.h>
  
  #include <acpi/processor.h>
  
  #include <asm/cpu.h>
  
  #include "internal.h"
  
  #define _COMPONENT	ACPI_PROCESSOR_COMPONENT
  
  ACPI_MODULE_NAME("processor");

  DEFINE_PER_CPU(struct acpi_processor *, processors);
  EXPORT_PER_CPU_SYMBOL(processors);

  /* --------------------------------------------------------------------------
                                  Errata Handling
     -------------------------------------------------------------------------- */
  
  struct acpi_processor_errata errata __read_mostly;
  EXPORT_SYMBOL_GPL(errata);
  
  static int acpi_processor_errata_piix4(struct pci_dev *dev)
  {
  	u8 value1 = 0;
  	u8 value2 = 0;
  
  
  	if (!dev)
  		return -EINVAL;
  
  	/*
  	 * Note that 'dev' references the PIIX4 ACPI Controller.
  	 */
  
  	switch (dev->revision) {
  	case 0:
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 A-step
  "));
  		break;
  	case 1:
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 B-step
  "));
  		break;
  	case 2:
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4E
  "));
  		break;
  	case 3:
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4M
  "));
  		break;
  	default:
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found unknown PIIX4
  "));
  		break;
  	}
  
  	switch (dev->revision) {
  
  	case 0:		/* PIIX4 A-step */
  	case 1:		/* PIIX4 B-step */
  		/*
  		 * See specification changes #13 ("Manual Throttle Duty Cycle")
  		 * and #14 ("Enabling and Disabling Manual Throttle"), plus
  		 * erratum #5 ("STPCLK# Deassertion Time") from the January
  		 * 2002 PIIX4 specification update.  Applies to only older
  		 * PIIX4 models.
  		 */
  		errata.piix4.throttle = 1;

  		fallthrough;

  
  	case 2:		/* PIIX4E */
  	case 3:		/* PIIX4M */
  		/*
  		 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
  		 * Livelock") from the January 2002 PIIX4 specification update.
  		 * Applies to all PIIX4 models.
  		 */
  
  		/*
  		 * BM-IDE
  		 * ------
  		 * Find the PIIX4 IDE Controller and get the Bus Master IDE
  		 * Status register address.  We'll use this later to read
  		 * each IDE controller's DMA status to make sure we catch all
  		 * DMA activity.
  		 */
  		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
  				     PCI_DEVICE_ID_INTEL_82371AB,
  				     PCI_ANY_ID, PCI_ANY_ID, NULL);
  		if (dev) {
  			errata.piix4.bmisx = pci_resource_start(dev, 4);
  			pci_dev_put(dev);
  		}
  
  		/*
  		 * Type-F DMA
  		 * ----------
  		 * Find the PIIX4 ISA Controller and read the Motherboard
  		 * DMA controller's status to see if Type-F (Fast) DMA mode
  		 * is enabled (bit 7) on either channel.  Note that we'll
  		 * disable C3 support if this is enabled, as some legacy
  		 * devices won't operate well if fast DMA is disabled.
  		 */
  		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
  				     PCI_DEVICE_ID_INTEL_82371AB_0,
  				     PCI_ANY_ID, PCI_ANY_ID, NULL);
  		if (dev) {
  			pci_read_config_byte(dev, 0x76, &value1);
  			pci_read_config_byte(dev, 0x77, &value2);
  			if ((value1 & 0x80) || (value2 & 0x80))
  				errata.piix4.fdma = 1;
  			pci_dev_put(dev);
  		}
  
  		break;
  	}
  
  	if (errata.piix4.bmisx)
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  				  "Bus master activity detection (BM-IDE) erratum enabled
  "));
  	if (errata.piix4.fdma)
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  				  "Type-F DMA livelock erratum (C3 disabled)
  "));
  
  	return 0;
  }

  static int acpi_processor_errata(void)

  {
  	int result = 0;
  	struct pci_dev *dev = NULL;

  	/*
  	 * PIIX4
  	 */
  	dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
  			     PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
  			     PCI_ANY_ID, NULL);
  	if (dev) {
  		result = acpi_processor_errata_piix4(dev);
  		pci_dev_put(dev);
  	}
  
  	return result;
  }
  
  /* --------------------------------------------------------------------------
                                  Initialization
     -------------------------------------------------------------------------- */
  
  #ifdef CONFIG_ACPI_HOTPLUG_CPU

  int __weak acpi_map_cpu(acpi_handle handle,

  		phys_cpuid_t physid, u32 acpi_id, int *pcpu)

  {
  	return -ENODEV;
  }
  
  int __weak acpi_unmap_cpu(int cpu)
  {
  	return -ENODEV;
  }
  
  int __weak arch_register_cpu(int cpu)
  {
  	return -ENODEV;
  }
  
  void __weak arch_unregister_cpu(int cpu) {}

  static int acpi_processor_hotadd_init(struct acpi_processor *pr)
  {
  	unsigned long long sta;
  	acpi_status status;
  	int ret;

  	if (invalid_phys_cpuid(pr->phys_id))

  		return -ENODEV;

  	status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
  	if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
  		return -ENODEV;

  	cpu_maps_update_begin();
  	cpu_hotplug_begin();

  	ret = acpi_map_cpu(pr->handle, pr->phys_id, pr->acpi_id, &pr->id);

  	if (ret)

  		goto out;

  
  	ret = arch_register_cpu(pr->id);
  	if (ret) {

  		acpi_unmap_cpu(pr->id);

  		goto out;

  	}
  
  	/*
  	 * CPU got hot-added, but cpu_data is not initialized yet.  Set a flag
  	 * to delay cpu_idle/throttling initialization and do it when the CPU
  	 * gets online for the first time.
  	 */
  	pr_info("CPU%d has been hot-added
  ", pr->id);
  	pr->flags.need_hotplug_init = 1;

  
  out:
  	cpu_hotplug_done();
  	cpu_maps_update_done();
  	return ret;

  }
  #else
  static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
  {
  	return -ENODEV;
  }
  #endif /* CONFIG_ACPI_HOTPLUG_CPU */
  
  static int acpi_processor_get_info(struct acpi_device *device)
  {
  	union acpi_object object = { 0 };
  	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
  	struct acpi_processor *pr = acpi_driver_data(device);

  	int device_declaration = 0;

  	acpi_status status = AE_OK;
  	static int cpu0_initialized;

  	unsigned long long value;

  	acpi_processor_errata();

  
  	/*
  	 * Check to see if we have bus mastering arbitration control.  This
  	 * is required for proper C3 usage (to maintain cache coherency).
  	 */
  	if (acpi_gbl_FADT.pm2_control_block && acpi_gbl_FADT.pm2_control_length) {
  		pr->flags.bm_control = 1;
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  				  "Bus mastering arbitration control present
  "));
  	} else
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  				  "No bus mastering arbitration control
  "));
  
  	if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
  		/* Declared with "Processor" statement; match ProcessorID */
  		status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
  		if (ACPI_FAILURE(status)) {
  			dev_err(&device->dev,
  				"Failed to evaluate processor object (0x%x)
  ",
  				status);
  			return -ENODEV;
  		}

  		pr->acpi_id = object.processor.proc_id;
  	} else {
  		/*
  		 * Declared with "Device" statement; match _UID.

  		 */

  		status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
  						NULL, &value);
  		if (ACPI_FAILURE(status)) {
  			dev_err(&device->dev,
  				"Failed to evaluate processor _UID (0x%x)
  ",
  				status);
  			return -ENODEV;
  		}
  		device_declaration = 1;
  		pr->acpi_id = value;
  	}

  	if (acpi_duplicate_processor_id(pr->acpi_id)) {

  		if (pr->acpi_id == 0xff)
  			dev_info_once(&device->dev,
  				"Entry not well-defined, consider updating BIOS
  ");
  		else
  			dev_err(&device->dev,
  				"Failed to get unique processor _UID (0x%x)
  ",
  				pr->acpi_id);

  		return -ENODEV;
  	}

  	pr->phys_id = acpi_get_phys_id(pr->handle, device_declaration,
  					pr->acpi_id);

  	if (invalid_phys_cpuid(pr->phys_id))

  		acpi_handle_debug(pr->handle, "failed to get CPU physical ID.
  ");

  	pr->id = acpi_map_cpuid(pr->phys_id, pr->acpi_id);

  	if (!cpu0_initialized && !acpi_has_cpu_in_madt()) {

  		cpu0_initialized = 1;

  		/*
  		 * Handle UP system running SMP kernel, with no CPU
  		 * entry in MADT
  		 */

  		if (invalid_logical_cpuid(pr->id) && (num_online_cpus() == 1))
  			pr->id = 0;

  	}

  
  	/*
  	 *  Extra Processor objects may be enumerated on MP systems with
  	 *  less than the max # of CPUs. They should be ignored _iff
  	 *  they are physically not present.

  	 *
  	 *  NOTE: Even if the processor has a cpuid, it may not be present
  	 *  because cpuid <-> apicid mapping is persistent now.

  	 */

  	if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id)) {

  		int ret = acpi_processor_hotadd_init(pr);
  		if (ret)
  			return ret;
  	}

  	/*
  	 * On some boxes several processors use the same processor bus id.
  	 * But they are located in different scope. For example:
  	 * \_SB.SCK0.CPU0
  	 * \_SB.SCK1.CPU0
  	 * Rename the processor device bus id. And the new bus id will be
  	 * generated as the following format:
  	 * CPU+CPU ID.
  	 */
  	sprintf(acpi_device_bid(device), "CPU%X", pr->id);
  	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d:%d]
  ", pr->id,
  			  pr->acpi_id));
  
  	if (!object.processor.pblk_address)
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No PBLK (NULL address)
  "));
  	else if (object.processor.pblk_length != 6)
  		dev_err(&device->dev, "Invalid PBLK length [%d]
  ",
  			    object.processor.pblk_length);
  	else {
  		pr->throttling.address = object.processor.pblk_address;
  		pr->throttling.duty_offset = acpi_gbl_FADT.duty_offset;
  		pr->throttling.duty_width = acpi_gbl_FADT.duty_width;
  
  		pr->pblk = object.processor.pblk_address;

  	}
  
  	/*
  	 * If ACPI describes a slot number for this CPU, we can use it to
  	 * ensure we get the right value in the "physical id" field
  	 * of /proc/cpuinfo
  	 */

  	status = acpi_evaluate_integer(pr->handle, "_SUN", NULL, &value);

  	if (ACPI_SUCCESS(status))

  		arch_fix_phys_package_id(pr->id, value);

  
  	return 0;
  }
  
  /*
   * Do not put anything in here which needs the core to be online.
   * For example MSR access or setting up things which check for cpuinfo_x86
   * (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
   * Such things have to be put in and set up by the processor driver's .probe().
   */
  static DEFINE_PER_CPU(void *, processor_device_array);

  static int acpi_processor_add(struct acpi_device *device,

  					const struct acpi_device_id *id)
  {
  	struct acpi_processor *pr;
  	struct device *dev;
  	int result = 0;
  
  	pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
  	if (!pr)
  		return -ENOMEM;
  
  	if (!zalloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
  		result = -ENOMEM;
  		goto err_free_pr;
  	}
  
  	pr->handle = device->handle;
  	strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
  	strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
  	device->driver_data = pr;
  
  	result = acpi_processor_get_info(device);
  	if (result) /* Processor is not physically present or unavailable */
  		return 0;

  	BUG_ON(pr->id >= nr_cpu_ids);
  
  	/*
  	 * Buggy BIOS check.
  	 * ACPI id of processors can be reported wrongly by the BIOS.
  	 * Don't trust it blindly
  	 */
  	if (per_cpu(processor_device_array, pr->id) != NULL &&
  	    per_cpu(processor_device_array, pr->id) != device) {
  		dev_warn(&device->dev,
  			"BIOS reported wrong ACPI id %d for the processor
  ",
  			pr->id);
  		/* Give up, but do not abort the namespace scan. */
  		goto err;
  	}
  	/*
  	 * processor_device_array is not cleared on errors to allow buggy BIOS
  	 * checks.
  	 */
  	per_cpu(processor_device_array, pr->id) = device;

  	per_cpu(processors, pr->id) = pr;

  
  	dev = get_cpu_device(pr->id);

  	if (!dev) {
  		result = -ENODEV;
  		goto err;
  	}

  	result = acpi_bind_one(dev, device);

  	if (result)
  		goto err;
  
  	pr->dev = dev;

  
  	/* Trigger the processor driver's .probe() if present. */
  	if (device_attach(dev) >= 0)
  		return 1;
  
  	dev_err(dev, "Processor driver could not be attached
  ");
  	acpi_unbind_one(dev);
  
   err:
  	free_cpumask_var(pr->throttling.shared_cpu_map);
  	device->driver_data = NULL;

  	per_cpu(processors, pr->id) = NULL;

   err_free_pr:
  	kfree(pr);
  	return result;
  }
  
  #ifdef CONFIG_ACPI_HOTPLUG_CPU
  /* --------------------------------------------------------------------------
                                      Removal
     -------------------------------------------------------------------------- */
  
  static void acpi_processor_remove(struct acpi_device *device)
  {
  	struct acpi_processor *pr;
  
  	if (!device || !acpi_driver_data(device))
  		return;
  
  	pr = acpi_driver_data(device);
  	if (pr->id >= nr_cpu_ids)
  		goto out;
  
  	/*
  	 * The only reason why we ever get here is CPU hot-removal.  The CPU is
  	 * already offline and the ACPI device removal locking prevents it from
  	 * being put back online at this point.
  	 *
  	 * Unbind the driver from the processor device and detach it from the
  	 * ACPI companion object.
  	 */
  	device_release_driver(pr->dev);
  	acpi_unbind_one(pr->dev);
  
  	/* Clean up. */
  	per_cpu(processor_device_array, pr->id) = NULL;

  	per_cpu(processors, pr->id) = NULL;

  	cpu_maps_update_begin();
  	cpu_hotplug_begin();

  	/* Remove the CPU. */

  	arch_unregister_cpu(pr->id);

  	acpi_unmap_cpu(pr->id);

  
  	cpu_hotplug_done();
  	cpu_maps_update_done();

  	try_offline_node(cpu_to_node(pr->id));

   out:
  	free_cpumask_var(pr->throttling.shared_cpu_map);
  	kfree(pr);
  }
  #endif /* CONFIG_ACPI_HOTPLUG_CPU */

  #ifdef CONFIG_X86
  static bool acpi_hwp_native_thermal_lvt_set;
  static acpi_status __init acpi_hwp_native_thermal_lvt_osc(acpi_handle handle,
  							  u32 lvl,
  							  void *context,
  							  void **rv)
  {
  	u8 sb_uuid_str[] = "4077A616-290C-47BE-9EBD-D87058713953";
  	u32 capbuf[2];
  	struct acpi_osc_context osc_context = {
  		.uuid_str = sb_uuid_str,
  		.rev = 1,
  		.cap.length = 8,
  		.cap.pointer = capbuf,
  	};
  
  	if (acpi_hwp_native_thermal_lvt_set)
  		return AE_CTRL_TERMINATE;
  
  	capbuf[0] = 0x0000;
  	capbuf[1] = 0x1000; /* set bit 12 */
  
  	if (ACPI_SUCCESS(acpi_run_osc(handle, &osc_context))) {
  		if (osc_context.ret.pointer && osc_context.ret.length > 1) {
  			u32 *capbuf_ret = osc_context.ret.pointer;
  
  			if (capbuf_ret[1] & 0x1000) {
  				acpi_handle_info(handle,
  					"_OSC native thermal LVT Acked
  ");
  				acpi_hwp_native_thermal_lvt_set = true;
  			}
  		}
  		kfree(osc_context.ret.pointer);
  	}
  
  	return AE_OK;
  }
  
  void __init acpi_early_processor_osc(void)
  {
  	if (boot_cpu_has(X86_FEATURE_HWP)) {
  		acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
  				    ACPI_UINT32_MAX,
  				    acpi_hwp_native_thermal_lvt_osc,
  				    NULL, NULL, NULL);
  		acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID,
  				 acpi_hwp_native_thermal_lvt_osc,
  				 NULL, NULL);
  	}
  }
  #endif

  /*
   * The following ACPI IDs are known to be suitable for representing as
   * processor devices.
   */
  static const struct acpi_device_id processor_device_ids[] = {
  
  	{ ACPI_PROCESSOR_OBJECT_HID, },
  	{ ACPI_PROCESSOR_DEVICE_HID, },
  
  	{ }
  };

  static struct acpi_scan_handler processor_handler = {

  	.ids = processor_device_ids,
  	.attach = acpi_processor_add,
  #ifdef CONFIG_ACPI_HOTPLUG_CPU
  	.detach = acpi_processor_remove,
  #endif
  	.hotplug = {
  		.enabled = true,
  	},
  };

  static int acpi_processor_container_attach(struct acpi_device *dev,
  					   const struct acpi_device_id *id)
  {
  	return 1;
  }
  
  static const struct acpi_device_id processor_container_ids[] = {
  	{ ACPI_PROCESSOR_CONTAINER_HID, },
  	{ }
  };
  
  static struct acpi_scan_handler processor_container_handler = {
  	.ids = processor_container_ids,
  	.attach = acpi_processor_container_attach,
  };

  /* The number of the unique processor IDs */
  static int nr_unique_ids __initdata;
  
  /* The number of the duplicate processor IDs */

  static int nr_duplicate_ids;

  
  /* Used to store the unique processor IDs */
  static int unique_processor_ids[] __initdata = {
  	[0 ... NR_CPUS - 1] = -1,
  };
  
  /* Used to store the duplicate processor IDs */

  static int duplicate_processor_ids[] = {

  	[0 ... NR_CPUS - 1] = -1,
  };
  
  static void __init processor_validated_ids_update(int proc_id)
  {
  	int i;
  
  	if (nr_unique_ids == NR_CPUS||nr_duplicate_ids == NR_CPUS)
  		return;
  
  	/*
  	 * Firstly, compare the proc_id with duplicate IDs, if the proc_id is
  	 * already in the IDs, do nothing.
  	 */
  	for (i = 0; i < nr_duplicate_ids; i++) {
  		if (duplicate_processor_ids[i] == proc_id)
  			return;
  	}
  
  	/*
  	 * Secondly, compare the proc_id with unique IDs, if the proc_id is in
  	 * the IDs, put it in the duplicate IDs.
  	 */
  	for (i = 0; i < nr_unique_ids; i++) {
  		if (unique_processor_ids[i] == proc_id) {
  			duplicate_processor_ids[nr_duplicate_ids] = proc_id;
  			nr_duplicate_ids++;
  			return;
  		}
  	}
  
  	/*
  	 * Lastly, the proc_id is a unique ID, put it in the unique IDs.
  	 */
  	unique_processor_ids[nr_unique_ids] = proc_id;
  	nr_unique_ids++;
  }
  
  static acpi_status __init acpi_processor_ids_walk(acpi_handle handle,
  						  u32 lvl,
  						  void *context,
  						  void **rv)
  {
  	acpi_status status;

  	acpi_object_type acpi_type;
  	unsigned long long uid;

  	union acpi_object object = { 0 };
  	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };

  	status = acpi_get_type(handle, &acpi_type);

  	if (ACPI_FAILURE(status))

  		return status;

  
  	switch (acpi_type) {
  	case ACPI_TYPE_PROCESSOR:
  		status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
  		if (ACPI_FAILURE(status))
  			goto err;
  		uid = object.processor.proc_id;
  		break;
  
  	case ACPI_TYPE_DEVICE:
  		status = acpi_evaluate_integer(handle, "_UID", NULL, &uid);
  		if (ACPI_FAILURE(status))
  			goto err;
  		break;
  	default:
  		goto err;
  	}
  
  	processor_validated_ids_update(uid);

  	return AE_OK;

  
  err:

  	/* Exit on error, but don't abort the namespace walk */

  	acpi_handle_info(handle, "Invalid processor object
  ");

  	return AE_OK;

  }

  static void __init acpi_processor_check_duplicates(void)

  {

  	/* check the correctness for all processors in ACPI namespace */

  	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
  						ACPI_UINT32_MAX,
  						acpi_processor_ids_walk,
  						NULL, NULL, NULL);

  	acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, acpi_processor_ids_walk,
  						NULL, NULL);

  }

  bool acpi_duplicate_processor_id(int proc_id)

  {
  	int i;
  
  	/*
  	 * compare the proc_id with duplicate IDs, if the proc_id is already
  	 * in the duplicate IDs, return true, otherwise, return false.
  	 */
  	for (i = 0; i < nr_duplicate_ids; i++) {
  		if (duplicate_processor_ids[i] == proc_id)
  			return true;
  	}
  	return false;
  }

  void __init acpi_processor_init(void)
  {

  	acpi_processor_check_duplicates();

  	acpi_scan_add_handler_with_hotplug(&processor_handler, "processor");

  	acpi_scan_add_handler(&processor_container_handler);

  }

  
  #ifdef CONFIG_ACPI_PROCESSOR_CSTATE
  /**
   * acpi_processor_claim_cst_control - Request _CST control from the platform.
   */
  bool acpi_processor_claim_cst_control(void)
  {
  	static bool cst_control_claimed;
  	acpi_status status;
  
  	if (!acpi_gbl_FADT.cst_control || cst_control_claimed)
  		return true;
  
  	status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
  				    acpi_gbl_FADT.cst_control, 8);
  	if (ACPI_FAILURE(status)) {
  		pr_warn("ACPI: Failed to claim processor _CST control
  ");
  		return false;
  	}
  
  	cst_control_claimed = true;
  	return true;
  }
  EXPORT_SYMBOL_GPL(acpi_processor_claim_cst_control);

  
  /**
   * acpi_processor_evaluate_cst - Evaluate the processor _CST control method.
   * @handle: ACPI handle of the processor object containing the _CST.
   * @cpu: The numeric ID of the target CPU.
   * @info: Object write the C-states information into.
   *
   * Extract the C-state information for the given CPU from the output of the _CST
   * control method under the corresponding ACPI processor object (or processor
   * device object) and populate @info with it.
   *
   * If any ACPI_ADR_SPACE_FIXED_HARDWARE C-states are found, invoke
   * acpi_processor_ffh_cstate_probe() to verify them and update the
   * cpu_cstate_entry data for @cpu.
   */
  int acpi_processor_evaluate_cst(acpi_handle handle, u32 cpu,
  				struct acpi_processor_power *info)
  {
  	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  	union acpi_object *cst;
  	acpi_status status;
  	u64 count;
  	int last_index = 0;
  	int i, ret = 0;
  
  	status = acpi_evaluate_object(handle, "_CST", NULL, &buffer);
  	if (ACPI_FAILURE(status)) {
  		acpi_handle_debug(handle, "No _CST
  ");
  		return -ENODEV;
  	}
  
  	cst = buffer.pointer;
  
  	/* There must be at least 2 elements. */
  	if (!cst || cst->type != ACPI_TYPE_PACKAGE || cst->package.count < 2) {
  		acpi_handle_warn(handle, "Invalid _CST output
  ");
  		ret = -EFAULT;
  		goto end;
  	}
  
  	count = cst->package.elements[0].integer.value;
  
  	/* Validate the number of C-states. */
  	if (count < 1 || count != cst->package.count - 1) {
  		acpi_handle_warn(handle, "Inconsistent _CST data
  ");
  		ret = -EFAULT;
  		goto end;
  	}
  
  	for (i = 1; i <= count; i++) {
  		union acpi_object *element;
  		union acpi_object *obj;
  		struct acpi_power_register *reg;
  		struct acpi_processor_cx cx;
  
  		/*
  		 * If there is not enough space for all C-states, skip the
  		 * excess ones and log a warning.
  		 */
  		if (last_index >= ACPI_PROCESSOR_MAX_POWER - 1) {
  			acpi_handle_warn(handle,
  					 "No room for more idle states (limit: %d)
  ",
  					 ACPI_PROCESSOR_MAX_POWER - 1);
  			break;
  		}
  
  		memset(&cx, 0, sizeof(cx));
  
  		element = &cst->package.elements[i];

  		if (element->type != ACPI_TYPE_PACKAGE) {
  			acpi_handle_info(handle, "_CST C%d type(%x) is not package, skip...
  ",
  					 i, element->type);

  			continue;

  		}

  		if (element->package.count != 4) {
  			acpi_handle_info(handle, "_CST C%d package count(%d) is not 4, skip...
  ",
  					 i, element->package.count);

  			continue;

  		}

  
  		obj = &element->package.elements[0];

  		if (obj->type != ACPI_TYPE_BUFFER) {
  			acpi_handle_info(handle, "_CST C%d package element[0] type(%x) is not buffer, skip...
  ",
  					 i, obj->type);

  			continue;

  		}

  
  		reg = (struct acpi_power_register *)obj->buffer.pointer;
  
  		obj = &element->package.elements[1];

  		if (obj->type != ACPI_TYPE_INTEGER) {
  			acpi_handle_info(handle, "_CST C[%d] package element[1] type(%x) is not integer, skip...
  ",
  					 i, obj->type);

  			continue;

  		}

  
  		cx.type = obj->integer.value;
  		/*
  		 * There are known cases in which the _CST output does not
  		 * contain C1, so if the type of the first state found is not
  		 * C1, leave an empty slot for C1 to be filled in later.
  		 */
  		if (i == 1 && cx.type != ACPI_STATE_C1)
  			last_index = 1;
  
  		cx.address = reg->address;
  		cx.index = last_index + 1;
  
  		if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
  			if (!acpi_processor_ffh_cstate_probe(cpu, &cx, reg)) {
  				/*
  				 * In the majority of cases _CST describes C1 as
  				 * a FIXED_HARDWARE C-state, but if the command
  				 * line forbids using MWAIT, use CSTATE_HALT for
  				 * C1 regardless.
  				 */
  				if (cx.type == ACPI_STATE_C1 &&
  				    boot_option_idle_override == IDLE_NOMWAIT) {
  					cx.entry_method = ACPI_CSTATE_HALT;
  					snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
  				} else {
  					cx.entry_method = ACPI_CSTATE_FFH;
  				}
  			} else if (cx.type == ACPI_STATE_C1) {
  				/*
  				 * In the special case of C1, FIXED_HARDWARE can
  				 * be handled by executing the HLT instruction.
  				 */
  				cx.entry_method = ACPI_CSTATE_HALT;
  				snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
  			} else {

  				acpi_handle_info(handle, "_CST C%d declares FIXED_HARDWARE C-state but not supported in hardware, skip...
  ",
  						 i);

  				continue;
  			}
  		} else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
  			cx.entry_method = ACPI_CSTATE_SYSTEMIO;
  			snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
  				 cx.address);
  		} else {

  			acpi_handle_info(handle, "_CST C%d space_id(%x) neither FIXED_HARDWARE nor SYSTEM_IO, skip...
  ",
  					 i, reg->space_id);

  			continue;
  		}
  
  		if (cx.type == ACPI_STATE_C1)
  			cx.valid = 1;
  
  		obj = &element->package.elements[2];

  		if (obj->type != ACPI_TYPE_INTEGER) {
  			acpi_handle_info(handle, "_CST C%d package element[2] type(%x) not integer, skip...
  ",
  					 i, obj->type);

  			continue;

  		}

  
  		cx.latency = obj->integer.value;
  
  		obj = &element->package.elements[3];

  		if (obj->type != ACPI_TYPE_INTEGER) {
  			acpi_handle_info(handle, "_CST C%d package element[3] type(%x) not integer, skip...
  ",
  					 i, obj->type);

  			continue;

  		}

  
  		memcpy(&info->states[++last_index], &cx, sizeof(cx));
  	}
  
  	acpi_handle_info(handle, "Found %d idle states
  ", last_index);
  
  	info->count = last_index;
  
        end:
  	kfree(buffer.pointer);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(acpi_processor_evaluate_cst);

  #endif /* CONFIG_ACPI_PROCESSOR_CSTATE */