Merge tag 'v3.3.7' into 3.3/master

[zen-stable.git] / drivers / cpufreq / acpi-cpufreq.c

/*
 * acpi-cpufreq.c - ACPI Processor P-States Driver
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *  Copyright (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
 *  Copyright (C) 2006       Denis Sadykov <denis.m.sadykov@intel.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

/* This file has been patched with Linux PHC: www.linux-phc.org
* Patch version: linux-phc-0.3.2
*/

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/compiler.h>
#include <linux/dmi.h>
#include <linux/slab.h>

#include <linux/acpi.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/uaccess.h>

#include <acpi/processor.h>

#include <asm/msr.h>
#include <asm/processor.h>
#include <asm/cpufeature.h>
#include "mperf.h"

MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
MODULE_DESCRIPTION("ACPI Processor P-States Driver");
MODULE_LICENSE("GPL");

enum {
        UNDEFINED_CAPABLE = 0,
        SYSTEM_INTEL_MSR_CAPABLE,
        SYSTEM_IO_CAPABLE,
};

#define INTEL_MSR_RANGE         (0xffff)
#define INTEL_MSR_VID_MASK      (0x00ff)
#define INTEL_MSR_FID_MASK      (0xff00)
#define INTEL_MSR_FID_SHIFT     (0x8)
#define PHC_VERSION_STRING      "0.3.2:2"

struct acpi_cpufreq_data {
        struct acpi_processor_performance *acpi_data;
        struct cpufreq_frequency_table *freq_table;
        unsigned int resume;
        unsigned int cpu_feature;
        acpi_integer *original_controls;
};

static DEFINE_PER_CPU(struct acpi_cpufreq_data *, acfreq_data);

/* acpi_perf_data is a pointer to percpu data. */
static struct acpi_processor_performance __percpu *acpi_perf_data;

static struct cpufreq_driver acpi_cpufreq_driver;

static unsigned int acpi_pstate_strict;

static int check_est_cpu(unsigned int cpuid)
{
        struct cpuinfo_x86 *cpu = &cpu_data(cpuid);

        return cpu_has(cpu, X86_FEATURE_EST);
}

static unsigned extract_io(u32 value, struct acpi_cpufreq_data *data)
{
        struct acpi_processor_performance *perf;
        int i;

        perf = data->acpi_data;

        for (i = 0; i < perf->state_count; i++) {
                if (value == perf->states[i].status)
                        return data->freq_table[i].frequency;
        }
        return 0;
}

static unsigned extract_msr(u32 msr, struct acpi_cpufreq_data *data)
{
        int i;
        u32 fid;
        struct acpi_processor_performance *perf;

        fid = msr & INTEL_MSR_FID_MASK;
        perf = data->acpi_data;

        for (i = 0; data->freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
                if (fid == (perf->states[data->freq_table[i].index].status & INTEL_MSR_FID_MASK))
                        return data->freq_table[i].frequency;
        }
        return data->freq_table[0].frequency;
}

static unsigned extract_freq(u32 val, struct acpi_cpufreq_data *data)
{
        switch (data->cpu_feature) {
        case SYSTEM_INTEL_MSR_CAPABLE:
                return extract_msr(val, data);
        case SYSTEM_IO_CAPABLE:
                return extract_io(val, data);
        default:
                return 0;
        }
}

struct msr_addr {
        u32 reg;
};

struct io_addr {
        u16 port;
        u8 bit_width;
};

struct drv_cmd {
        unsigned int type;
        const struct cpumask *mask;
        union {
                struct msr_addr msr;
                struct io_addr io;
        } addr;
        u32 val;
};

/* Called via smp_call_function_single(), on the target CPU */
static void do_drv_read(void *_cmd)
{
        struct drv_cmd *cmd = _cmd;
        u32 h;

        switch (cmd->type) {
        case SYSTEM_INTEL_MSR_CAPABLE:
                rdmsr(cmd->addr.msr.reg, cmd->val, h);
                break;
        case SYSTEM_IO_CAPABLE:
                acpi_os_read_port((acpi_io_address)cmd->addr.io.port,
                                &cmd->val,
                                (u32)cmd->addr.io.bit_width);
                break;
        default:
                break;
        }
}

/* Called via smp_call_function_many(), on the target CPUs */
static void do_drv_write(void *_cmd)
{
        struct drv_cmd *cmd = _cmd;
        u32 lo, hi;

        switch (cmd->type) {
        case SYSTEM_INTEL_MSR_CAPABLE:
                rdmsr(cmd->addr.msr.reg, lo, hi);
                lo = (lo & ~INTEL_MSR_RANGE) | (cmd->val & INTEL_MSR_RANGE);
                wrmsr(cmd->addr.msr.reg, lo, hi);
                break;
        case SYSTEM_IO_CAPABLE:
                acpi_os_write_port((acpi_io_address)cmd->addr.io.port,
                                cmd->val,
                                (u32)cmd->addr.io.bit_width);
                break;
        default:
                break;
        }
}

static void drv_read(struct drv_cmd *cmd)
{
        int err;
        cmd->val = 0;

        err = smp_call_function_any(cmd->mask, do_drv_read, cmd, 1);
        WARN_ON_ONCE(err);      /* smp_call_function_any() was buggy? */
}

static void drv_write(struct drv_cmd *cmd)
{
        int this_cpu;

        this_cpu = get_cpu();
        if (cpumask_test_cpu(this_cpu, cmd->mask))
                do_drv_write(cmd);
        smp_call_function_many(cmd->mask, do_drv_write, cmd, 1);
        put_cpu();
}

static u32 get_cur_val(const struct cpumask *mask)
{
        struct acpi_processor_performance *perf;
        struct drv_cmd cmd;

        if (unlikely(cpumask_empty(mask)))
                return 0;

        switch (per_cpu(acfreq_data, cpumask_first(mask))->cpu_feature) {
        case SYSTEM_INTEL_MSR_CAPABLE:
                cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
                cmd.addr.msr.reg = MSR_IA32_PERF_STATUS;
                break;
        case SYSTEM_IO_CAPABLE:
                cmd.type = SYSTEM_IO_CAPABLE;
                perf = per_cpu(acfreq_data, cpumask_first(mask))->acpi_data;
                cmd.addr.io.port = perf->control_register.address;
                cmd.addr.io.bit_width = perf->control_register.bit_width;
                break;
        default:
                return 0;
        }

        cmd.mask = mask;
        drv_read(&cmd);

        pr_debug("get_cur_val = %u\n", cmd.val);

        return cmd.val;
}

static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, cpu);
        unsigned int freq;
        unsigned int cached_freq;

        pr_debug("get_cur_freq_on_cpu (%d)\n", cpu);

        if (unlikely(data == NULL ||
                     data->acpi_data == NULL || data->freq_table == NULL)) {
                return 0;
        }

        cached_freq = data->freq_table[data->acpi_data->state].frequency;
        freq = extract_freq(get_cur_val(cpumask_of(cpu)), data);
        if (freq != cached_freq) {
                /*
                 * The dreaded BIOS frequency change behind our back.
                 * Force set the frequency on next target call.
                 */
                data->resume = 1;
        }

        pr_debug("cur freq = %u\n", freq);

        return freq;
}

static unsigned int check_freqs(const struct cpumask *mask, unsigned int freq,
                                struct acpi_cpufreq_data *data)
{
        unsigned int cur_freq;
        unsigned int i;

        for (i = 0; i < 100; i++) {
                cur_freq = extract_freq(get_cur_val(mask), data);
                if (cur_freq == freq)
                        return 1;
                udelay(10);
        }
        return 0;
}

static int acpi_cpufreq_target(struct cpufreq_policy *policy,
                               unsigned int target_freq, unsigned int relation)
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
        struct acpi_processor_performance *perf;
        struct cpufreq_freqs freqs;
        struct drv_cmd cmd;
        unsigned int next_state = 0; /* Index into freq_table */
        unsigned int next_perf_state = 0; /* Index into perf table */
        unsigned int i;
        int result = 0;

        pr_debug("acpi_cpufreq_target %d (%d)\n", target_freq, policy->cpu);

        if (unlikely(data == NULL ||
             data->acpi_data == NULL || data->freq_table == NULL)) {
                return -ENODEV;
        }

        perf = data->acpi_data;
        result = cpufreq_frequency_table_target(policy,
                                                data->freq_table,
                                                target_freq,
                                                relation, &next_state);
        if (unlikely(result)) {
                result = -ENODEV;
                goto out;
        }

        next_perf_state = data->freq_table[next_state].index;
        if (perf->state == next_perf_state) {
                if (unlikely(data->resume)) {
                        pr_debug("Called after resume, resetting to P%d\n",
                                next_perf_state);
                        data->resume = 0;
                } else {
                        pr_debug("Already at target state (P%d)\n",
                                next_perf_state);
                        goto out;
                }
        }

        switch (data->cpu_feature) {
        case SYSTEM_INTEL_MSR_CAPABLE:
                cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
                cmd.addr.msr.reg = MSR_IA32_PERF_CTL;
                cmd.val = (u32) perf->states[next_perf_state].control;
                break;
        case SYSTEM_IO_CAPABLE:
                cmd.type = SYSTEM_IO_CAPABLE;
                cmd.addr.io.port = perf->control_register.address;
                cmd.addr.io.bit_width = perf->control_register.bit_width;
                cmd.val = (u32) perf->states[next_perf_state].control;
                break;
        default:
                result = -ENODEV;
                goto out;
        }

        /* cpufreq holds the hotplug lock, so we are safe from here on */
        if (policy->shared_type != CPUFREQ_SHARED_TYPE_ANY)
                cmd.mask = policy->cpus;
        else
                cmd.mask = cpumask_of(policy->cpu);

        freqs.old = perf->states[perf->state].core_frequency * 1000;
        freqs.new = data->freq_table[next_state].frequency;
        for_each_cpu(i, policy->cpus) {
                freqs.cpu = i;
                cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
        }

        drv_write(&cmd);

        if (acpi_pstate_strict) {
                if (!check_freqs(cmd.mask, freqs.new, data)) {
                        pr_debug("acpi_cpufreq_target failed (%d)\n",
                                policy->cpu);
                        result = -EAGAIN;
                        goto out;
                }
        }

        for_each_cpu(i, policy->cpus) {
                freqs.cpu = i;
                cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
        }
        perf->state = next_perf_state;

out:
        return result;
}

static int acpi_cpufreq_verify(struct cpufreq_policy *policy)
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);

        pr_debug("acpi_cpufreq_verify\n");

        return cpufreq_frequency_table_verify(policy, data->freq_table);
}

static unsigned long
acpi_cpufreq_guess_freq(struct acpi_cpufreq_data *data, unsigned int cpu)
{
        struct acpi_processor_performance *perf = data->acpi_data;

        if (cpu_khz) {
                /* search the closest match to cpu_khz */
                unsigned int i;
                unsigned long freq;
                unsigned long freqn = perf->states[0].core_frequency * 1000;

                for (i = 0; i < (perf->state_count-1); i++) {
                        freq = freqn;
                        freqn = perf->states[i+1].core_frequency * 1000;
                        if ((2 * cpu_khz) > (freqn + freq)) {
                                perf->state = i;
                                return freq;
                        }
                }
                perf->state = perf->state_count-1;
                return freqn;
        } else {
                /* assume CPU is at P0... */
                perf->state = 0;
                return perf->states[0].core_frequency * 1000;
        }
}

static void free_acpi_perf_data(void)
{
        unsigned int i;

        /* Freeing a NULL pointer is OK, and alloc_percpu zeroes. */
        for_each_possible_cpu(i)
                free_cpumask_var(per_cpu_ptr(acpi_perf_data, i)
                                 ->shared_cpu_map);
        free_percpu(acpi_perf_data);
}

/*
 * acpi_cpufreq_early_init - initialize ACPI P-States library
 *
 * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
 * in order to determine correct frequency and voltage pairings. We can
 * do _PDC and _PSD and find out the processor dependency for the
 * actual init that will happen later...
 */
static int __init acpi_cpufreq_early_init(void)
{
        unsigned int i;
        pr_debug("acpi_cpufreq_early_init\n");

        acpi_perf_data = alloc_percpu(struct acpi_processor_performance);
        if (!acpi_perf_data) {
                pr_debug("Memory allocation error for acpi_perf_data.\n");
                return -ENOMEM;
        }
        for_each_possible_cpu(i) {
                if (!zalloc_cpumask_var_node(
                        &per_cpu_ptr(acpi_perf_data, i)->shared_cpu_map,
                        GFP_KERNEL, cpu_to_node(i))) {

                        /* Freeing a NULL pointer is OK: alloc_percpu zeroes. */
                        free_acpi_perf_data();
                        return -ENOMEM;
                }
        }

        /* Do initialization in ACPI core */
        acpi_processor_preregister_performance(acpi_perf_data);
        return 0;
}

#ifdef CONFIG_SMP
/*
 * Some BIOSes do SW_ANY coordination internally, either set it up in hw
 * or do it in BIOS firmware and won't inform about it to OS. If not
 * detected, this has a side effect of making CPU run at a different speed
 * than OS intended it to run at. Detect it and handle it cleanly.
 */
static int bios_with_sw_any_bug;

static int sw_any_bug_found(const struct dmi_system_id *d)
{
        bios_with_sw_any_bug = 1;
        return 0;
}

static const struct dmi_system_id sw_any_bug_dmi_table[] = {
        {
                .callback = sw_any_bug_found,
                .ident = "Supermicro Server X6DLP",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Supermicro"),
                        DMI_MATCH(DMI_BIOS_VERSION, "080010"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "X6DLP"),
                },
        },
        { }
};

static int acpi_cpufreq_blacklist(struct cpuinfo_x86 *c)
{
        /* Intel Xeon Processor 7100 Series Specification Update
         * http://www.intel.com/Assets/PDF/specupdate/314554.pdf
         * AL30: A Machine Check Exception (MCE) Occurring during an
         * Enhanced Intel SpeedStep Technology Ratio Change May Cause
         * Both Processor Cores to Lock Up. */
        if (c->x86_vendor == X86_VENDOR_INTEL) {
                if ((c->x86 == 15) &&
                    (c->x86_model == 6) &&
                    (c->x86_mask == 8)) {
                        printk(KERN_INFO "acpi-cpufreq: Intel(R) "
                            "Xeon(R) 7100 Errata AL30, processors may "
                            "lock up on frequency changes: disabling "
                            "acpi-cpufreq.\n");
                        return -ENODEV;
                    }
                }
        return 0;
}
#endif

static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
        unsigned int i;
        unsigned int valid_states = 0;
        unsigned int cpu = policy->cpu;
        struct acpi_cpufreq_data *data;
        unsigned int result = 0;
        struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
        struct acpi_processor_performance *perf;
#ifdef CONFIG_SMP
        static int blacklisted;
#endif

        pr_debug("acpi_cpufreq_cpu_init\n");

#ifdef CONFIG_SMP
        if (blacklisted)
                return blacklisted;
        blacklisted = acpi_cpufreq_blacklist(c);
        if (blacklisted)
                return blacklisted;
#endif

        data = kzalloc(sizeof(struct acpi_cpufreq_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->acpi_data = per_cpu_ptr(acpi_perf_data, cpu);
        per_cpu(acfreq_data, cpu) = data;

        if (cpu_has(c, X86_FEATURE_CONSTANT_TSC))
                acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;

        result = acpi_processor_register_performance(data->acpi_data, cpu);
        if (result)
                goto err_free;

        perf = data->acpi_data;
        policy->shared_type = perf->shared_type;

        /*
         * Will let policy->cpus know about dependency only when software
         * coordination is required.
         */
        if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
            policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
                cpumask_copy(policy->cpus, perf->shared_cpu_map);
        }
        cpumask_copy(policy->related_cpus, perf->shared_cpu_map);

#ifdef CONFIG_SMP
        dmi_check_system(sw_any_bug_dmi_table);
        if (bios_with_sw_any_bug && cpumask_weight(policy->cpus) == 1) {
                policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
                cpumask_copy(policy->cpus, cpu_core_mask(cpu));
        }
#endif

        /* capability check */
        if (perf->state_count <= 1) {
                pr_debug("No P-States\n");
                result = -ENODEV;
                goto err_unreg;
        }

        if (perf->control_register.space_id != perf->status_register.space_id) {
                result = -ENODEV;
                goto err_unreg;
        }

        switch (perf->control_register.space_id) {
        case ACPI_ADR_SPACE_SYSTEM_IO:
                pr_debug("SYSTEM IO addr space\n");
                data->cpu_feature = SYSTEM_IO_CAPABLE;
                break;
        case ACPI_ADR_SPACE_FIXED_HARDWARE:
                pr_debug("HARDWARE addr space\n");
                if (!check_est_cpu(cpu)) {
                        result = -ENODEV;
                        goto err_unreg;
                }
                data->cpu_feature = SYSTEM_INTEL_MSR_CAPABLE;
                break;
        default:
                pr_debug("Unknown addr space %d\n",
                        (u32) (perf->control_register.space_id));
                result = -ENODEV;
                goto err_unreg;
        }

        data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
                    (perf->state_count+1), GFP_KERNEL);
        if (!data->freq_table) {
                result = -ENOMEM;
                goto err_unreg;
        }

        /* detect transition latency */
        policy->cpuinfo.transition_latency = 0;
        for (i = 0; i < perf->state_count; i++) {
                if ((perf->states[i].transition_latency * 1000) >
                    policy->cpuinfo.transition_latency)
                        policy->cpuinfo.transition_latency =
                            perf->states[i].transition_latency * 1000;
        }

        /* Check for high latency (>20uS) from buggy BIOSes, like on T42 */
        if (perf->control_register.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE &&
            policy->cpuinfo.transition_latency > 20 * 1000) {
                policy->cpuinfo.transition_latency = 20 * 1000;
                printk_once(KERN_INFO
                            "P-state transition latency capped at 20 uS\n");
        }

        /* table init */
        for (i = 0; i < perf->state_count; i++) {
                if (i > 0 && perf->states[i].core_frequency >=
                    data->freq_table[valid_states-1].frequency / 1000)
                        continue;

                data->freq_table[valid_states].index = i;
                data->freq_table[valid_states].frequency =
                    perf->states[i].core_frequency * 1000;
                valid_states++;
        }
        data->freq_table[valid_states].frequency = CPUFREQ_TABLE_END;
        perf->state = 0;

        result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
        if (result)
                goto err_freqfree;

        if (perf->states[0].core_frequency * 1000 != policy->cpuinfo.max_freq)
                printk(KERN_WARNING FW_WARN "P-state 0 is not max freq\n");

        switch (perf->control_register.space_id) {
        case ACPI_ADR_SPACE_SYSTEM_IO:
                /* Current speed is unknown and not detectable by IO port */
                policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
                break;
        case ACPI_ADR_SPACE_FIXED_HARDWARE:
                acpi_cpufreq_driver.get = get_cur_freq_on_cpu;
                policy->cur = get_cur_freq_on_cpu(cpu);
                break;
        default:
                break;
        }

        /* notify BIOS that we exist */
        acpi_processor_notify_smm(THIS_MODULE);

        /* Check for APERF/MPERF support in hardware */
        if (boot_cpu_has(X86_FEATURE_APERFMPERF))
                acpi_cpufreq_driver.getavg = cpufreq_get_measured_perf;

        pr_debug("CPU%u - ACPI performance management activated.\n", cpu);
        for (i = 0; i < perf->state_count; i++)
                pr_debug("     %cP%d: %d MHz, %d mW, %d uS\n",
                        (i == perf->state ? '*' : ' '), i,
                        (u32) perf->states[i].core_frequency,
                        (u32) perf->states[i].power,
                        (u32) perf->states[i].transition_latency);

        cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);

        /*
         * the first call to ->target() should result in us actually
         * writing something to the appropriate registers.
         */
        data->resume = 1;

        return result;

err_freqfree:
        kfree(data->freq_table);
err_unreg:
        acpi_processor_unregister_performance(perf, cpu);
err_free:
        kfree(data);
        per_cpu(acfreq_data, cpu) = NULL;

        return result;
}

static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);

        pr_debug("acpi_cpufreq_cpu_exit\n");

        if (data) {
                cpufreq_frequency_table_put_attr(policy->cpu);
                per_cpu(acfreq_data, policy->cpu) = NULL;
                acpi_processor_unregister_performance(data->acpi_data,
                                                      policy->cpu);
                if (data->original_controls)
                        kfree(data->original_controls);
                kfree(data->freq_table);
                kfree(data);
        }

        return 0;
}

static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);

        pr_debug("acpi_cpufreq_resume\n");

        data->resume = 1;

        return 0;
}

/* sysfs interface to change operating points voltages */

static unsigned int extract_fid_from_control(unsigned int control)
{
        return ((control & INTEL_MSR_FID_MASK) >> INTEL_MSR_FID_SHIFT);
}

static unsigned int extract_vid_from_control(unsigned int control)
{
        return (control & INTEL_MSR_VID_MASK);
}


static bool check_cpu_control_capability(struct acpi_cpufreq_data *data) {
 /* check if the cpu we are running on is capable of setting new control data
  *
  */
        if (unlikely(data == NULL ||
                     data->acpi_data == NULL ||
                     data->freq_table == NULL ||
                     data->cpu_feature != SYSTEM_INTEL_MSR_CAPABLE)) {
                return false;
        } else {
                return true;
        };
}


static ssize_t check_origial_table (struct acpi_cpufreq_data *data)
{

        struct acpi_processor_performance *acpi_data;
        struct cpufreq_frequency_table *freq_table;
        unsigned int state_index;

        acpi_data = data->acpi_data;
        freq_table = data->freq_table;

        if (data->original_controls == NULL) {
                // Backup original control values
                data->original_controls = kcalloc(acpi_data->state_count,
                                                  sizeof(acpi_integer), GFP_KERNEL);
                if (data->original_controls == NULL) {
                        printk("failed to allocate memory for original control values\n");
                        return -ENOMEM;
                }
                for (state_index = 0; state_index < acpi_data->state_count; state_index++) {
                        data->original_controls[state_index] = acpi_data->states[state_index].control;
                }
        }
        return 0;
}

static ssize_t show_freq_attr_vids(struct cpufreq_policy *policy, char *buf)
 /* display phc's voltage id's
  *
  */
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
        struct acpi_processor_performance *acpi_data;
        struct cpufreq_frequency_table *freq_table;
        unsigned int i;
        unsigned int vid;
        ssize_t count = 0;

        if (!check_cpu_control_capability(data)) return -ENODEV; //check if CPU is capable of changing controls

        acpi_data = data->acpi_data;
        freq_table = data->freq_table;

        for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
                vid = extract_vid_from_control(acpi_data->states[freq_table[i].index].control);
                count += sprintf(&buf[count], "%u ", vid);
        }
        count += sprintf(&buf[count], "\n");

        return count;
}

static ssize_t show_freq_attr_default_vids(struct cpufreq_policy *policy, char *buf)
 /* display acpi's default voltage id's
  *
  */
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
        struct cpufreq_frequency_table *freq_table;
        unsigned int i;
        unsigned int vid;
        ssize_t count = 0;
        ssize_t retval;

        if (!check_cpu_control_capability(data)) return -ENODEV; //check if CPU is capable of changing controls

        retval = check_origial_table(data);
        if (0 != retval)
                return retval;

        freq_table = data->freq_table;

        for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
                vid = extract_vid_from_control(data->original_controls[freq_table[i].index]);
                count += sprintf(&buf[count], "%u ", vid);
        }
        count += sprintf(&buf[count], "\n");

        return count;
}

static ssize_t show_freq_attr_fids(struct cpufreq_policy *policy, char *buf)
 /* display phc's frequeny id's
  *
  */
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
        struct acpi_processor_performance *acpi_data;
        struct cpufreq_frequency_table *freq_table;
        unsigned int i;
        unsigned int fid;
        ssize_t count = 0;

        if (!check_cpu_control_capability(data)) return -ENODEV; //check if CPU is capable of changing controls

        acpi_data = data->acpi_data;
        freq_table = data->freq_table;

        for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
                fid = extract_fid_from_control(acpi_data->states[freq_table[i].index].control);
                count += sprintf(&buf[count], "%u ", fid);
        }
        count += sprintf(&buf[count], "\n");

        return count;
}

static ssize_t show_freq_attr_controls(struct cpufreq_policy *policy, char *buf)
 /* display phc's controls for the cpu (frequency id's and related voltage id's)
  *
  */
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
        struct acpi_processor_performance *acpi_data;
        struct cpufreq_frequency_table *freq_table;
        unsigned int i;
        unsigned int fid;
        unsigned int vid;
        ssize_t count = 0;

        if (!check_cpu_control_capability(data)) return -ENODEV; //check if CPU is capable of changing controls

        acpi_data = data->acpi_data;
        freq_table = data->freq_table;

        for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
                fid = extract_fid_from_control(acpi_data->states[freq_table[i].index].control);
                vid = extract_vid_from_control(acpi_data->states[freq_table[i].index].control);
                count += sprintf(&buf[count], "%u:%u ", fid, vid);
        }
        count += sprintf(&buf[count], "\n");

        return count;
}

static ssize_t show_freq_attr_default_controls(struct cpufreq_policy *policy, char *buf)
 /* display acpi's default controls for the cpu (frequency id's and related voltage id's)
  *
  */
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
        struct cpufreq_frequency_table *freq_table;
        unsigned int i;
        unsigned int fid;
        unsigned int vid;
        ssize_t count = 0;
        ssize_t retval;

        if (!check_cpu_control_capability(data)) return -ENODEV; //check if CPU is capable of changing controls

        retval = check_origial_table(data);
        if (0 != retval)
                return retval;

        freq_table = data->freq_table;

        for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
                fid = extract_fid_from_control(data->original_controls[freq_table[i].index]);
                vid = extract_vid_from_control(data->original_controls[freq_table[i].index]);
                count += sprintf(&buf[count], "%u:%u ", fid, vid);
        }
        count += sprintf(&buf[count], "\n");

        return count;
}


static ssize_t store_freq_attr_vids(struct cpufreq_policy *policy, const char *buf, size_t count)
 /* store the voltage id's for the related frequency
  * We are going to do some sanity checks here to prevent users
  * from setting higher voltages than the default one.
  */
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
        struct acpi_processor_performance *acpi_data;
        struct cpufreq_frequency_table *freq_table;
        unsigned int freq_index;
        unsigned int state_index;
        unsigned int new_vid;
        unsigned int original_vid;
        unsigned int new_control;
        unsigned int original_control;
        const char *curr_buf = buf;
        char *next_buf;
        ssize_t retval;

        if (!check_cpu_control_capability(data)) return -ENODEV; //check if CPU is capable of changing controls

        retval = check_origial_table(data);
        if (0 != retval)
                return retval;

        acpi_data = data->acpi_data;
        freq_table = data->freq_table;

        /* for each value taken from the sysfs interfalce (phc_vids) get entrys and convert them to unsigned long integers*/
        for (freq_index = 0; freq_table[freq_index].frequency != CPUFREQ_TABLE_END; freq_index++) {
                new_vid = simple_strtoul(curr_buf, &next_buf, 10);
                if (next_buf == curr_buf) {
                        if ((curr_buf - buf == count - 1) && (*curr_buf == '\n')) {   //end of line?
                                curr_buf++;
                                break;
                        }
                        //if we didn't got end of line but there is nothing more to read something went wrong...
                        printk("failed to parse vid value at %i (%s)\n", freq_index, curr_buf);
                        return -EINVAL;
                }

                state_index = freq_table[freq_index].index;
                original_control = data->original_controls[state_index];
                original_vid = original_control & INTEL_MSR_VID_MASK;

                /* before we store the values we do some checks to prevent
                 * users to set up values higher than the default one
                 */
                if (new_vid <= original_vid) {
                        new_control = (original_control & ~INTEL_MSR_VID_MASK) | new_vid;
                        pr_debug("setting control at %i to %x (default is %x)\n",
                                freq_index, new_control, original_control);
                        acpi_data->states[state_index].control = new_control;

                } else {
                        printk("skipping vid at %i, %u is greater than default %u\n",
                               freq_index, new_vid, original_vid);
                }

                curr_buf = next_buf;
                /* jump over value seperators (space or comma).
                 * There could be more than one space or comma character
                 * to separate two values so we better do it using a loop.
                 */
                while ((curr_buf - buf < count) && ((*curr_buf == ' ') || (*curr_buf == ','))) {
                        curr_buf++;
                }
        }

        /* set new voltage for current frequency */
        data->resume = 1;
        acpi_cpufreq_target(policy, get_cur_freq_on_cpu(policy->cpu), CPUFREQ_RELATION_L);

        return curr_buf - buf;
}

static ssize_t store_freq_attr_controls(struct cpufreq_policy *policy, const char *buf, size_t count)
 /* store the controls (frequency id's and related voltage id's)
  * We are going to do some sanity checks here to prevent users
  * from setting higher voltages than the default one.
  */
{
        struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
        struct acpi_processor_performance *acpi_data;
        struct cpufreq_frequency_table *freq_table;
        const char   *curr_buf;
        unsigned int  op_count;
        unsigned int  state_index;
        int           isok;
        char         *next_buf;
        ssize_t       retval;
        unsigned int  new_vid;
        unsigned int  original_vid;
        unsigned int  new_fid;
        unsigned int  old_fid;
        unsigned int  original_control;
        unsigned int  old_control;
        unsigned int  new_control;
        int           found;

        if (!check_cpu_control_capability(data)) return -ENODEV;

        retval = check_origial_table(data);
        if (0 != retval)
                return retval;

        acpi_data = data->acpi_data;
        freq_table = data->freq_table;

        op_count = 0;
        curr_buf = buf;
        next_buf = NULL;
        isok     = 1;

        while ( (isok) && (curr_buf != NULL) )
        {
                op_count++;
                // Parse fid
                new_fid = simple_strtoul(curr_buf, &next_buf, 10);
                if ((next_buf != curr_buf) && (next_buf != NULL))
                {
                        // Parse separator between frequency and voltage
                        curr_buf = next_buf;
                        next_buf = NULL;
                        if (*curr_buf==':')
                        {
                                curr_buf++;
                                // Parse vid
                                new_vid = simple_strtoul(curr_buf, &next_buf, 10);
                                if ((next_buf != curr_buf) && (next_buf != NULL))
                                {
                                        found = 0;
                                        for (state_index = 0; state_index < acpi_data->state_count; state_index++) {
                                                old_control = acpi_data->states[state_index].control;
                                                old_fid = extract_fid_from_control(old_control);
                                                if (new_fid == old_fid)
                                                {
                                                        found = 1;
                                                        original_control = data->original_controls[state_index];
                                                        original_vid = extract_vid_from_control(original_control);
                                                        if (new_vid <= original_vid)
                                                        {
                                                                new_control = (original_control & ~INTEL_MSR_VID_MASK) | new_vid;
                                                                pr_debug("setting control at %i to %x (default is %x)\n",
                                                                        state_index, new_control, original_control);
                                                                acpi_data->states[state_index].control = new_control;

                                                        } else {
                                                                printk("skipping vid at %i, %u is greater than default %u\n",
                                                                       state_index, new_vid, original_vid);
                                                        }
                                                }
                                        }

                                        if (found == 0)
                                        {
                                                printk("operating point # %u not found (FID = %u)\n", op_count, new_fid);
                                                isok = 0;
                                        }

                                        // Parse seprator before next operating point, if any
                                        curr_buf = next_buf;
                                        next_buf = NULL;
                                        if ((*curr_buf == ',') || (*curr_buf == ' '))
                                                curr_buf++;
                                        else
                                                curr_buf = NULL;
                                }
                                else
                                {
                                        printk("failed to parse VID of operating point # %u (%s)\n", op_count, curr_buf);
                                        isok = 0;
                                }
                        }
                        else
                        {
                                printk("failed to parse operating point # %u (%s)\n", op_count, curr_buf);
                                isok = 0;
                        }
                }
                else
                {
                        printk("failed to parse FID of operating point # %u (%s)\n", op_count, curr_buf);
                        isok = 0;
                }
        }

        if (isok)
        {
                retval = count;
                /* set new voltage at current frequency */
                data->resume = 1;
                acpi_cpufreq_target(policy, get_cur_freq_on_cpu(policy->cpu), CPUFREQ_RELATION_L);
        }
        else
        {
                retval = -EINVAL;
        }

        return retval;
}

static ssize_t show_freq_attr_phc_version(struct cpufreq_policy *policy, char *buf)
 /* print out the phc version string set at the beginning of that file
  */
{
        ssize_t count = 0;
        count += sprintf(&buf[count], "%s\n", PHC_VERSION_STRING);
        return count;
}



static struct freq_attr cpufreq_freq_attr_phc_version =
{
        /*display phc's version string*/
       .attr = { .name = "phc_version", .mode = 0444 },
       .show = show_freq_attr_phc_version,
       .store = NULL,
};

static struct freq_attr cpufreq_freq_attr_vids =
{
        /*display phc's voltage id's for the cpu*/
       .attr = { .name = "phc_vids", .mode = 0644 },
       .show = show_freq_attr_vids,
       .store = store_freq_attr_vids,
};

static struct freq_attr cpufreq_freq_attr_default_vids =
{
        /*display acpi's default frequency id's for the cpu*/
       .attr = { .name = "phc_default_vids", .mode = 0444 },
       .show = show_freq_attr_default_vids,
       .store = NULL,
};

static struct freq_attr cpufreq_freq_attr_fids =
{
        /*display phc's default frequency id's for the cpu*/
       .attr = { .name = "phc_fids", .mode = 0444 },
       .show = show_freq_attr_fids,
       .store = NULL,
};

static struct freq_attr cpufreq_freq_attr_controls =
{
        /*display phc's current voltage/frequency controls for the cpu*/
       .attr = { .name = "phc_controls", .mode = 0644 },
       .show = show_freq_attr_controls,
       .store = store_freq_attr_controls,
};

static struct freq_attr cpufreq_freq_attr_default_controls =
{
        /*display acpi's default voltage/frequency controls for the cpu*/
       .attr = { .name = "phc_default_controls", .mode = 0444 },
       .show = show_freq_attr_default_controls,
       .store = NULL,
};


static struct freq_attr *acpi_cpufreq_attr[] = {
        &cpufreq_freq_attr_scaling_available_freqs,
        &cpufreq_freq_attr_phc_version,
        &cpufreq_freq_attr_vids,
        &cpufreq_freq_attr_default_vids,
        &cpufreq_freq_attr_fids,
        &cpufreq_freq_attr_controls,
        &cpufreq_freq_attr_default_controls,
        NULL,
};

static struct cpufreq_driver acpi_cpufreq_driver = {
        .verify         = acpi_cpufreq_verify,
        .target         = acpi_cpufreq_target,
        .bios_limit     = acpi_processor_get_bios_limit,
        .init           = acpi_cpufreq_cpu_init,
        .exit           = acpi_cpufreq_cpu_exit,
        .resume         = acpi_cpufreq_resume,
        .name           = "acpi-cpufreq",
        .owner          = THIS_MODULE,
        .attr           = acpi_cpufreq_attr,
};

static int __init acpi_cpufreq_init(void)
{
        int ret;

        if (acpi_disabled)
                return 0;

        pr_debug("acpi_cpufreq_init\n");

        ret = acpi_cpufreq_early_init();
        if (ret)
                return ret;

        ret = cpufreq_register_driver(&acpi_cpufreq_driver);
        if (ret)
                free_acpi_perf_data();

        return ret;
}

static void __exit acpi_cpufreq_exit(void)
{
        pr_debug("acpi_cpufreq_exit\n");

        cpufreq_unregister_driver(&acpi_cpufreq_driver);

        free_acpi_perf_data();
}

module_param(acpi_pstate_strict, uint, 0644);
MODULE_PARM_DESC(acpi_pstate_strict,
        "value 0 or non-zero. non-zero -> strict ACPI checks are "
        "performed during frequency changes.");

late_initcall(acpi_cpufreq_init);
module_exit(acpi_cpufreq_exit);

MODULE_ALIAS("acpi");