/*
 * 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\n", 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.\n");
}

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;
}

/*
 * Do a quick check if the systems looks like it should use ACPI
 * cpufreq. We look at a _PCT method being available, but don't
 * do a whole lot of sanity checks.
 */
void acpi_processor_load_module(struct acpi_processor *pr)
{
        static int requested;
        acpi_status status = 0;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

        if (!arch_has_acpi_pdc() || requested)
                return;
        status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);
        if (!ACPI_FAILURE(status)) {
                printk(KERN_INFO PREFIX "Requesting acpi_cpufreq\n");
                request_module_nowait("acpi_cpufreq");
                requested = 1;
        }
        kfree(buffer.pointer);
}

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\n");
                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)\n");
                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)\n");
                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;
        int last_invalid = -1;


        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\n");
                result = -EFAULT;
                goto end;
        }

        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d performance states\n",
                          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\n", 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]\n",
                                  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 found for processor %d: 0x%llx MHz\n",
                               pr->id, px->core_frequency);
                        if (last_invalid == -1)
                                last_invalid = i;
                } else {
                        if (last_invalid != -1) {
                                /*
                                 * Copy this valid entry over last_invalid entry
                                 */
                                memcpy(&(pr->performance->states[last_invalid]),
                                       px, sizeof(struct acpi_processor_px));
                                ++last_invalid;
                        }
                }
        }

        if (last_invalid == 0) {
                printk(KERN_ERR FW_BUG PREFIX
                       "No valid BIOS _PSS frequency found for processor %d\n", pr->id);
                result = -EFAULT;
                kfree(pr->performance->states);
                pr->performance->states = NULL;
        }

        if (last_invalid > 0)
                pr->performance->state_count = last_invalid;

      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\n"));
                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\n");
        }
#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\n"));
                module_put(calling_module);
                return 0;
        }

        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "Writing pstate_control [0x%x] to smi_command [0x%x]\n",
                          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\n");
                result = -EFAULT;
                goto end;
        }

        if (psd->package.count != 1) {
                printk(KERN_ERR PREFIX "Invalid _PSD data\n");
                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\n");
                result = -EFAULT;
                goto end;
        }

        if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
                printk(KERN_ERR PREFIX "Unknown _PSD:num_entries\n");
                result = -EFAULT;
                goto end;
        }

        if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
                printk(KERN_ERR PREFIX "Unknown _PSD:revision\n");
                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\n");
                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);