/*
   * processor_perflib.c - ACPI Processor P-States Library ($Revision: 71 $)
   *
   *  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>
   *  			- Added processor hotplug support
   *
   *
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation; either version 2 of the License, or (at
   *  your option) any later version.
   *
   *  This program is distributed in the hope that it will be useful, but
   *  WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   *  General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License along
   *  with this program; if not, write to the Free Software Foundation, Inc.,
   *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
   *
   */

  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/cpufreq.h>

  #include <linux/slab.h>

  #ifdef CONFIG_X86

  #include <asm/cpufeature.h>

  #endif

  
  #include <acpi/acpi_bus.h>

  #include <acpi/acpi_drivers.h>

  #include <acpi/processor.h>

  #define PREFIX "ACPI: "

  #define ACPI_PROCESSOR_CLASS		"processor"

  #define ACPI_PROCESSOR_FILE_PERFORMANCE	"performance"
  #define _COMPONENT		ACPI_PROCESSOR_COMPONENT

  ACPI_MODULE_NAME("processor_perflib");

  static DEFINE_MUTEX(performance_mutex);

  
  /*
   * _PPC support is implemented as a CPUfreq policy notifier:
   * This means each time a CPUfreq driver registered also with
   * the ACPI core is asked to change the speed policy, the maximum
   * value is adjusted so that it is within the platform limit.
   *
   * Also, when a new platform limit value is detected, the CPUfreq
   * policy is adjusted accordingly.
   */

  /* ignore_ppc:
   * -1 -> cpufreq low level drivers not initialized -> _PSS, etc. not called yet
   *       ignore _PPC
   *  0 -> cpufreq low level drivers initialized -> consider _PPC values
   *  1 -> ignore _PPC totally -> forced by user through boot param
   */

  static int ignore_ppc = -1;

  module_param(ignore_ppc, int, 0644);

  MODULE_PARM_DESC(ignore_ppc, "If the frequency of your machine gets wrongly" \
  		 "limited by BIOS, this should help");

  #define PPC_REGISTERED   1
  #define PPC_IN_USE       2

  static int acpi_processor_ppc_status;

  
  static int acpi_processor_ppc_notifier(struct notifier_block *nb,

  				       unsigned long event, void *data)

  {
  	struct cpufreq_policy *policy = data;
  	struct acpi_processor *pr;
  	unsigned int ppc = 0;

  	if (event == CPUFREQ_START && ignore_ppc <= 0) {
  		ignore_ppc = 0;
  		return 0;
  	}

  	if (ignore_ppc)
  		return 0;

  	if (event != CPUFREQ_INCOMPATIBLE)

  		return 0;
  
  	mutex_lock(&performance_mutex);

  	pr = per_cpu(processors, policy->cpu);

  	if (!pr || !pr->performance)
  		goto out;

  	ppc = (unsigned int)pr->performance_platform_limit;

  	if (ppc >= pr->performance->state_count)

  		goto out;
  
  	cpufreq_verify_within_limits(policy, 0,

  				     pr->performance->states[ppc].
  				     core_frequency * 1000);

        out:

  	mutex_unlock(&performance_mutex);

  
  	return 0;
  }

  static struct notifier_block acpi_ppc_notifier_block = {
  	.notifier_call = acpi_processor_ppc_notifier,
  };

  static int acpi_processor_get_platform_limit(struct acpi_processor *pr)

  {

  	acpi_status status = 0;

  	unsigned long long ppc = 0;

  
  	if (!pr)

  		return -EINVAL;

  
  	/*
  	 * _PPC indicates the maximum state currently supported by the platform
  	 * (e.g. 0 = states 0..n; 1 = states 1..n; etc.
  	 */
  	status = acpi_evaluate_integer(pr->handle, "_PPC", NULL, &ppc);
  
  	if (status != AE_NOT_FOUND)
  		acpi_processor_ppc_status |= PPC_IN_USE;

  	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {

  		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PPC"));

  		return -ENODEV;

  	}

  	pr_debug("CPU %d: _PPC is %d - frequency %s limited
  ", pr->id,

  		       (int)ppc, ppc ? "" : "not");

  	pr->performance_platform_limit = (int)ppc;

  	return 0;

  }

  #define ACPI_PROCESSOR_NOTIFY_PERFORMANCE	0x80
  /*
   * acpi_processor_ppc_ost: Notify firmware the _PPC evaluation status
   * @handle: ACPI processor handle
   * @status: the status code of _PPC evaluation
   *	0: success. OSPM is now using the performance state specificed.
   *	1: failure. OSPM has not changed the number of P-states in use
   */
  static void acpi_processor_ppc_ost(acpi_handle handle, int status)
  {
  	union acpi_object params[2] = {
  		{.type = ACPI_TYPE_INTEGER,},
  		{.type = ACPI_TYPE_INTEGER,},
  	};
  	struct acpi_object_list arg_list = {2, params};
  	acpi_handle temp;
  
  	params[0].integer.value = ACPI_PROCESSOR_NOTIFY_PERFORMANCE;
  	params[1].integer.value =  status;
  
  	/* when there is no _OST , skip it */
  	if (ACPI_FAILURE(acpi_get_handle(handle, "_OST", &temp)))
  		return;
  
  	acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
  	return;
  }
  
  int acpi_processor_ppc_has_changed(struct acpi_processor *pr, int event_flag)

  {

  	int ret;

  	if (ignore_ppc) {
  		/*
  		 * Only when it is notification event, the _OST object
  		 * will be evaluated. Otherwise it is skipped.
  		 */
  		if (event_flag)
  			acpi_processor_ppc_ost(pr->handle, 1);

  		return 0;

  	}

  
  	ret = acpi_processor_get_platform_limit(pr);

  	/*
  	 * Only when it is notification event, the _OST object
  	 * will be evaluated. Otherwise it is skipped.
  	 */
  	if (event_flag) {
  		if (ret < 0)
  			acpi_processor_ppc_ost(pr->handle, 1);
  		else
  			acpi_processor_ppc_ost(pr->handle, 0);
  	}

  	if (ret < 0)
  		return (ret);
  	else
  		return cpufreq_update_policy(pr->id);
  }

  int acpi_processor_get_bios_limit(int cpu, unsigned int *limit)
  {
  	struct acpi_processor *pr;
  
  	pr = per_cpu(processors, cpu);
  	if (!pr || !pr->performance || !pr->performance->state_count)
  		return -ENODEV;
  	*limit = pr->performance->states[pr->performance_platform_limit].
  		core_frequency * 1000;
  	return 0;
  }
  EXPORT_SYMBOL(acpi_processor_get_bios_limit);

  void acpi_processor_ppc_init(void)
  {
  	if (!cpufreq_register_notifier
  	    (&acpi_ppc_notifier_block, CPUFREQ_POLICY_NOTIFIER))

  		acpi_processor_ppc_status |= PPC_REGISTERED;
  	else

  		printk(KERN_DEBUG
  		       "Warning: Processor Platform Limit not supported.
  ");

  }

  void acpi_processor_ppc_exit(void)
  {

  	if (acpi_processor_ppc_status & PPC_REGISTERED)

  		cpufreq_unregister_notifier(&acpi_ppc_notifier_block,
  					    CPUFREQ_POLICY_NOTIFIER);

  
  	acpi_processor_ppc_status &= ~PPC_REGISTERED;
  }

  static int acpi_processor_get_performance_control(struct acpi_processor *pr)

  {

  	int result = 0;
  	acpi_status status = 0;
  	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  	union acpi_object *pct = NULL;
  	union acpi_object obj = { 0 };

  
  	status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);

  	if (ACPI_FAILURE(status)) {

  		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PCT"));

  		return -ENODEV;

  	}

  	pct = (union acpi_object *)buffer.pointer;

  	if (!pct || (pct->type != ACPI_TYPE_PACKAGE)

  	    || (pct->package.count != 2)) {

  		printk(KERN_ERR PREFIX "Invalid _PCT data
  ");

  		result = -EFAULT;
  		goto end;
  	}
  
  	/*
  	 * control_register
  	 */
  
  	obj = pct->package.elements[0];
  
  	if ((obj.type != ACPI_TYPE_BUFFER)

  	    || (obj.buffer.length < sizeof(struct acpi_pct_register))
  	    || (obj.buffer.pointer == NULL)) {

  		printk(KERN_ERR PREFIX "Invalid _PCT data (control_register)
  ");

  		result = -EFAULT;
  		goto end;
  	}

  	memcpy(&pr->performance->control_register, obj.buffer.pointer,
  	       sizeof(struct acpi_pct_register));

  
  	/*
  	 * status_register
  	 */
  
  	obj = pct->package.elements[1];
  
  	if ((obj.type != ACPI_TYPE_BUFFER)

  	    || (obj.buffer.length < sizeof(struct acpi_pct_register))
  	    || (obj.buffer.pointer == NULL)) {

  		printk(KERN_ERR PREFIX "Invalid _PCT data (status_register)
  ");

  		result = -EFAULT;
  		goto end;
  	}

  	memcpy(&pr->performance->status_register, obj.buffer.pointer,
  	       sizeof(struct acpi_pct_register));

        end:

  	kfree(buffer.pointer);

  	return result;

  }

  static int acpi_processor_get_performance_states(struct acpi_processor *pr)

  {

  	int result = 0;
  	acpi_status status = AE_OK;
  	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  	struct acpi_buffer format = { sizeof("NNNNNN"), "NNNNNN" };
  	struct acpi_buffer state = { 0, NULL };
  	union acpi_object *pss = NULL;
  	int i;

  
  	status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);

  	if (ACPI_FAILURE(status)) {

  		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PSS"));

  		return -ENODEV;

  	}

  	pss = buffer.pointer;

  	if (!pss || (pss->type != ACPI_TYPE_PACKAGE)) {

  		printk(KERN_ERR PREFIX "Invalid _PSS data
  ");

  		result = -EFAULT;
  		goto end;
  	}
  
  	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d performance states
  ",

  			  pss->package.count));

  
  	pr->performance->state_count = pss->package.count;

  	pr->performance->states =
  	    kmalloc(sizeof(struct acpi_processor_px) * pss->package.count,
  		    GFP_KERNEL);

  	if (!pr->performance->states) {
  		result = -ENOMEM;
  		goto end;
  	}
  
  	for (i = 0; i < pr->performance->state_count; i++) {
  
  		struct acpi_processor_px *px = &(pr->performance->states[i]);
  
  		state.length = sizeof(struct acpi_processor_px);
  		state.pointer = px;
  
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d
  ", i));
  
  		status = acpi_extract_package(&(pss->package.elements[i]),

  					      &format, &state);

  		if (ACPI_FAILURE(status)) {

  			ACPI_EXCEPTION((AE_INFO, status, "Invalid _PSS data"));

  			result = -EFAULT;
  			kfree(pr->performance->states);
  			goto end;
  		}
  
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,

  				  "State [%d]: core_frequency[%d] power[%d] transition_latency[%d] bus_master_latency[%d] control[0x%x] status[0x%x]
  ",
  				  i,
  				  (u32) px->core_frequency,
  				  (u32) px->power,
  				  (u32) px->transition_latency,
  				  (u32) px->bus_master_latency,
  				  (u32) px->control, (u32) px->status));

  		/*
   		 * Check that ACPI's u64 MHz will be valid as u32 KHz in cpufreq
  		 */
  		if (!px->core_frequency ||
  		    ((u32)(px->core_frequency * 1000) !=
  		     (px->core_frequency * 1000))) {
  			printk(KERN_ERR FW_BUG PREFIX
  			       "Invalid BIOS _PSS frequency: 0x%llx MHz
  ",
  			       px->core_frequency);

  			result = -EFAULT;
  			kfree(pr->performance->states);
  			goto end;
  		}
  	}

        end:

  	kfree(buffer.pointer);

  	return result;

  }

  static int acpi_processor_get_performance_info(struct acpi_processor *pr)

  {

  	int result = 0;
  	acpi_status status = AE_OK;
  	acpi_handle handle = NULL;

  	if (!pr || !pr->performance || !pr->handle)

  		return -EINVAL;

  	status = acpi_get_handle(pr->handle, "_PCT", &handle);
  	if (ACPI_FAILURE(status)) {
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,

  				  "ACPI-based processor performance control unavailable
  "));

  		return -ENODEV;

  	}
  
  	result = acpi_processor_get_performance_control(pr);
  	if (result)

  		goto update_bios;

  
  	result = acpi_processor_get_performance_states(pr);
  	if (result)

  		goto update_bios;

  	/* We need to call _PPC once when cpufreq starts */
  	if (ignore_ppc != 1)
  		result = acpi_processor_get_platform_limit(pr);
  
  	return result;

  
  	/*
  	 * Having _PPC but missing frequencies (_PSS, _PCT) is a very good hint that
  	 * the BIOS is older than the CPU and does not know its frequencies
  	 */
   update_bios:

  #ifdef CONFIG_X86

  	if (ACPI_SUCCESS(acpi_get_handle(pr->handle, "_PPC", &handle))){
  		if(boot_cpu_has(X86_FEATURE_EST))
  			printk(KERN_WARNING FW_BUG "BIOS needs update for CPU "
  			       "frequency support
  ");
  	}

  #endif

  	return result;

  }

  int acpi_processor_notify_smm(struct module *calling_module)
  {
  	acpi_status status;
  	static int is_done = 0;

  
  	if (!(acpi_processor_ppc_status & PPC_REGISTERED))

  		return -EBUSY;

  
  	if (!try_module_get(calling_module))

  		return -EINVAL;

  	/* is_done is set to negative if an error occurred,
  	 * and to postitive if _no_ error occurred, but SMM

  	 * was already notified. This avoids double notification
  	 * which might lead to unexpected results...
  	 */
  	if (is_done > 0) {
  		module_put(calling_module);

  		return 0;

  	} else if (is_done < 0) {

  		module_put(calling_module);

  		return is_done;

  	}
  
  	is_done = -EIO;

  	/* Can't write pstate_control to smi_command if either value is zero */

  	if ((!acpi_gbl_FADT.smi_command) || (!acpi_gbl_FADT.pstate_control)) {

  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No SMI port or pstate_control
  "));

  		module_put(calling_module);

  		return 0;

  	}

  	ACPI_DEBUG_PRINT((ACPI_DB_INFO,

  			  "Writing pstate_control [0x%x] to smi_command [0x%x]
  ",

  			  acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command));

  	status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
  				    (u32) acpi_gbl_FADT.pstate_control, 8);

  	if (ACPI_FAILURE(status)) {

  		ACPI_EXCEPTION((AE_INFO, status,

  				"Failed to write pstate_control [0x%x] to "

  				"smi_command [0x%x]", acpi_gbl_FADT.pstate_control,
  				acpi_gbl_FADT.smi_command));

  		module_put(calling_module);

  		return status;

  	}
  
  	/* Success. If there's no _PPC, we need to fear nothing, so
  	 * we can allow the cpufreq driver to be rmmod'ed. */
  	is_done = 1;
  
  	if (!(acpi_processor_ppc_status & PPC_IN_USE))
  		module_put(calling_module);

  	return 0;

  }

  EXPORT_SYMBOL(acpi_processor_notify_smm);

  static int acpi_processor_get_psd(struct acpi_processor	*pr)
  {
  	int result = 0;
  	acpi_status status = AE_OK;
  	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
  	struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
  	struct acpi_buffer state = {0, NULL};
  	union acpi_object  *psd = NULL;
  	struct acpi_psd_package *pdomain;

  	status = acpi_evaluate_object(pr->handle, "_PSD", NULL, &buffer);
  	if (ACPI_FAILURE(status)) {

  		return -ENODEV;

  	}

  	psd = buffer.pointer;

  	if (!psd || (psd->type != ACPI_TYPE_PACKAGE)) {

  		printk(KERN_ERR PREFIX "Invalid _PSD data
  ");

  		result = -EFAULT;
  		goto end;
  	}
  
  	if (psd->package.count != 1) {

  		printk(KERN_ERR PREFIX "Invalid _PSD data
  ");

  		result = -EFAULT;
  		goto end;
  	}
  
  	pdomain = &(pr->performance->domain_info);
  
  	state.length = sizeof(struct acpi_psd_package);
  	state.pointer = pdomain;
  
  	status = acpi_extract_package(&(psd->package.elements[0]),
  		&format, &state);
  	if (ACPI_FAILURE(status)) {

  		printk(KERN_ERR PREFIX "Invalid _PSD data
  ");

  		result = -EFAULT;
  		goto end;
  	}
  
  	if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {

  		printk(KERN_ERR PREFIX "Unknown _PSD:num_entries
  ");

  		result = -EFAULT;
  		goto end;
  	}
  
  	if (pdomain->revision != ACPI_PSD_REV0_REVISION) {

  		printk(KERN_ERR PREFIX "Unknown _PSD:revision
  ");

  		result = -EFAULT;
  		goto end;
  	}

  	if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
  	    pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
  	    pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
  		printk(KERN_ERR PREFIX "Invalid _PSD:coord_type
  ");
  		result = -EFAULT;
  		goto end;
  	}

  end:

  	kfree(buffer.pointer);

  	return result;

  }
  
  int acpi_processor_preregister_performance(

  		struct acpi_processor_performance __percpu *performance)

  {
  	int count, count_target;
  	int retval = 0;
  	unsigned int i, j;

  	cpumask_var_t covered_cpus;

  	struct acpi_processor *pr;
  	struct acpi_psd_package *pdomain;
  	struct acpi_processor *match_pr;
  	struct acpi_psd_package *match_pdomain;

  	if (!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))

  		return -ENOMEM;

  	mutex_lock(&performance_mutex);

  	/*
  	 * Check if another driver has already registered, and abort before
  	 * changing pr->performance if it has. Check input data as well.
  	 */

  	for_each_possible_cpu(i) {

  		pr = per_cpu(processors, i);

  		if (!pr) {
  			/* Look only at processors in ACPI namespace */
  			continue;
  		}
  
  		if (pr->performance) {
  			retval = -EBUSY;

  			goto err_out;

  		}

  		if (!performance || !per_cpu_ptr(performance, i)) {

  			retval = -EINVAL;

  			goto err_out;

  		}

  	}
  
  	/* Call _PSD for all CPUs */
  	for_each_possible_cpu(i) {
  		pr = per_cpu(processors, i);
  		if (!pr)
  			continue;

  		pr->performance = per_cpu_ptr(performance, i);

  		cpumask_set_cpu(i, pr->performance->shared_cpu_map);

  		if (acpi_processor_get_psd(pr)) {
  			retval = -EINVAL;
  			continue;
  		}
  	}
  	if (retval)
  		goto err_ret;
  
  	/*
  	 * Now that we have _PSD data from all CPUs, lets setup P-state 
  	 * domain info.
  	 */

  	for_each_possible_cpu(i) {

  		pr = per_cpu(processors, i);

  		if (!pr)
  			continue;

  		if (cpumask_test_cpu(i, covered_cpus))

  			continue;
  
  		pdomain = &(pr->performance->domain_info);

  		cpumask_set_cpu(i, pr->performance->shared_cpu_map);
  		cpumask_set_cpu(i, covered_cpus);

  		if (pdomain->num_processors <= 1)
  			continue;
  
  		/* Validate the Domain info */
  		count_target = pdomain->num_processors;
  		count = 1;

  		if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)

  			pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;

  		else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
  			pr->performance->shared_type = CPUFREQ_SHARED_TYPE_HW;
  		else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)

  			pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ANY;

  		for_each_possible_cpu(j) {

  			if (i == j)
  				continue;

  			match_pr = per_cpu(processors, j);

  			if (!match_pr)
  				continue;
  
  			match_pdomain = &(match_pr->performance->domain_info);
  			if (match_pdomain->domain != pdomain->domain)
  				continue;
  
  			/* Here i and j are in the same domain */
  
  			if (match_pdomain->num_processors != count_target) {
  				retval = -EINVAL;
  				goto err_ret;
  			}
  
  			if (pdomain->coord_type != match_pdomain->coord_type) {
  				retval = -EINVAL;
  				goto err_ret;
  			}

  			cpumask_set_cpu(j, covered_cpus);
  			cpumask_set_cpu(j, pr->performance->shared_cpu_map);

  			count++;
  		}

  		for_each_possible_cpu(j) {

  			if (i == j)
  				continue;

  			match_pr = per_cpu(processors, j);

  			if (!match_pr)
  				continue;
  
  			match_pdomain = &(match_pr->performance->domain_info);
  			if (match_pdomain->domain != pdomain->domain)
  				continue;
  
  			match_pr->performance->shared_type = 
  					pr->performance->shared_type;

  			cpumask_copy(match_pr->performance->shared_cpu_map,
  				     pr->performance->shared_cpu_map);

  		}
  	}
  
  err_ret:

  	for_each_possible_cpu(i) {

  		pr = per_cpu(processors, i);

  		if (!pr || !pr->performance)
  			continue;
  
  		/* Assume no coordination on any error parsing domain info */
  		if (retval) {

  			cpumask_clear(pr->performance->shared_cpu_map);
  			cpumask_set_cpu(i, pr->performance->shared_cpu_map);

  			pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
  		}
  		pr->performance = NULL; /* Will be set for real in register */
  	}

  err_out:

  	mutex_unlock(&performance_mutex);

  	free_cpumask_var(covered_cpus);

  	return retval;

  }
  EXPORT_SYMBOL(acpi_processor_preregister_performance);

  int

  acpi_processor_register_performance(struct acpi_processor_performance
  				    *performance, unsigned int cpu)

  {
  	struct acpi_processor *pr;

  	if (!(acpi_processor_ppc_status & PPC_REGISTERED))

  		return -EINVAL;

  	mutex_lock(&performance_mutex);

  	pr = per_cpu(processors, cpu);

  	if (!pr) {

  		mutex_unlock(&performance_mutex);

  		return -ENODEV;

  	}
  
  	if (pr->performance) {

  		mutex_unlock(&performance_mutex);

  		return -EBUSY;

  	}

  	WARN_ON(!performance);

  	pr->performance = performance;
  
  	if (acpi_processor_get_performance_info(pr)) {
  		pr->performance = NULL;

  		mutex_unlock(&performance_mutex);

  		return -EIO;

  	}

  	mutex_unlock(&performance_mutex);

  	return 0;

  }

  EXPORT_SYMBOL(acpi_processor_register_performance);

  
  void

  acpi_processor_unregister_performance(struct acpi_processor_performance
  				      *performance, unsigned int cpu)

  {
  	struct acpi_processor *pr;

  	mutex_lock(&performance_mutex);

  	pr = per_cpu(processors, cpu);

  	if (!pr) {

  		mutex_unlock(&performance_mutex);

  		return;

  	}

  	if (pr->performance)
  		kfree(pr->performance->states);

  	pr->performance = NULL;

  	mutex_unlock(&performance_mutex);

  	return;

  }

  EXPORT_SYMBOL(acpi_processor_unregister_performance);