/* [<][>][^][v][top][bottom][index][help] */
DEFINITIONS
This source file includes following definitions.
- check_est_cpu
- extract_io
- extract_msr
- extract_freq
- do_drv_read
- do_drv_write
- drv_read
- drv_write
- get_cur_val
- get_measured_perf
- get_cur_freq_on_cpu
- check_freqs
- acpi_cpufreq_target
- acpi_cpufreq_verify
- acpi_cpufreq_guess_freq
- acpi_cpufreq_early_init
- sw_any_bug_found
- acpi_cpufreq_cpu_init
- acpi_cpufreq_cpu_exit
- acpi_cpufreq_resume
- acpi_cpufreq_init
- acpi_cpufreq_exit
/*
* acpi-cpufreq.c - ACPI Processor P-States Driver ($Revision: 1.4 $)
*
* 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.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#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/acpi.h>
#include <acpi/processor.h>
#include <asm/io.h>
#include <asm/msr.h>
#include <asm/processor.h>
#include <asm/cpufeature.h>
#include <asm/delay.h>
#include <asm/uaccess.h>
#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
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 CPUID_6_ECX_APERFMPERF_CAPABILITY (0x1)
struct acpi_cpufreq_data {
struct acpi_processor_performance *acpi_data;
struct cpufreq_frequency_table *freq_table;
unsigned int max_freq;
unsigned int resume;
unsigned int cpu_feature;
};
static DEFINE_PER_CPU(struct acpi_cpufreq_data *, drv_data);
/* acpi_perf_data is a pointer to percpu data. */
static struct acpi_processor_performance *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);
if (cpu->x86_vendor != X86_VENDOR_INTEL ||
!cpu_has(cpu, X86_FEATURE_EST))
return 0;
return 1;
}
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;
struct acpi_processor_performance *perf;
msr &= INTEL_MSR_RANGE;
perf = data->acpi_data;
for (i=0; data->freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
if (msr == perf->states[data->freq_table[i].index].status)
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;
};
typedef union {
struct msr_addr msr;
struct io_addr io;
} drv_addr_union;
struct drv_cmd {
unsigned int type;
cpumask_t mask;
drv_addr_union addr;
u32 val;
};
static void do_drv_read(struct drv_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;
}
}
static void do_drv_write(struct drv_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)
{
cpumask_t saved_mask = current->cpus_allowed;
cmd->val = 0;
set_cpus_allowed_ptr(current, &cmd->mask);
do_drv_read(cmd);
set_cpus_allowed_ptr(current, &saved_mask);
}
static void drv_write(struct drv_cmd *cmd)
{
cpumask_t saved_mask = current->cpus_allowed;
unsigned int i;
for_each_cpu_mask_nr(i, cmd->mask) {
set_cpus_allowed_ptr(current, &cpumask_of_cpu(i));
do_drv_write(cmd);
}
set_cpus_allowed_ptr(current, &saved_mask);
return;
}
static u32 get_cur_val(const cpumask_t *mask)
{
struct acpi_processor_performance *perf;
struct drv_cmd cmd;
if (unlikely(cpus_empty(*mask)))
return 0;
switch (per_cpu(drv_data, first_cpu(*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(drv_data, first_cpu(*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);
dprintk("get_cur_val = %u\n", cmd.val);
return cmd.val;
}
/*
* Return the measured active (C0) frequency on this CPU since last call
* to this function.
* Input: cpu number
* Return: Average CPU frequency in terms of max frequency (zero on error)
*
* We use IA32_MPERF and IA32_APERF MSRs to get the measured performance
* over a period of time, while CPU is in C0 state.
* IA32_MPERF counts at the rate of max advertised frequency
* IA32_APERF counts at the rate of actual CPU frequency
* Only IA32_APERF/IA32_MPERF ratio is architecturally defined and
* no meaning should be associated with absolute values of these MSRs.
*/
static unsigned int get_measured_perf(struct cpufreq_policy *policy,
unsigned int cpu)
{
union {
struct {
u32 lo;
u32 hi;
} split;
u64 whole;
} aperf_cur, mperf_cur;
cpumask_t saved_mask;
unsigned int perf_percent;
unsigned int retval;
saved_mask = current->cpus_allowed;
set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
if (get_cpu() != cpu) {
/* We were not able to run on requested processor */
put_cpu();
return 0;
}
rdmsr(MSR_IA32_APERF, aperf_cur.split.lo, aperf_cur.split.hi);
rdmsr(MSR_IA32_MPERF, mperf_cur.split.lo, mperf_cur.split.hi);
wrmsr(MSR_IA32_APERF, 0,0);
wrmsr(MSR_IA32_MPERF, 0,0);
#ifdef __i386__
/*
* We dont want to do 64 bit divide with 32 bit kernel
* Get an approximate value. Return failure in case we cannot get
* an approximate value.
*/
if (unlikely(aperf_cur.split.hi || mperf_cur.split.hi)) {
int shift_count;
u32 h;
h = max_t(u32, aperf_cur.split.hi, mperf_cur.split.hi);
shift_count = fls(h);
aperf_cur.whole >>= shift_count;
mperf_cur.whole >>= shift_count;
}
if (((unsigned long)(-1) / 100) < aperf_cur.split.lo) {
int shift_count = 7;
aperf_cur.split.lo >>= shift_count;
mperf_cur.split.lo >>= shift_count;
}
if (aperf_cur.split.lo && mperf_cur.split.lo)
perf_percent = (aperf_cur.split.lo * 100) / mperf_cur.split.lo;
else
perf_percent = 0;
#else
if (unlikely(((unsigned long)(-1) / 100) < aperf_cur.whole)) {
int shift_count = 7;
aperf_cur.whole >>= shift_count;
mperf_cur.whole >>= shift_count;
}
if (aperf_cur.whole && mperf_cur.whole)
perf_percent = (aperf_cur.whole * 100) / mperf_cur.whole;
else
perf_percent = 0;
#endif
retval = per_cpu(drv_data, policy->cpu)->max_freq * perf_percent / 100;
put_cpu();
set_cpus_allowed_ptr(current, &saved_mask);
dprintk("cpu %d: performance percent %d\n", cpu, perf_percent);
return retval;
}
static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
{
struct acpi_cpufreq_data *data = per_cpu(drv_data, cpu);
unsigned int freq;
unsigned int cached_freq;
dprintk("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(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;
}
dprintk("cur freq = %u\n", freq);
return freq;
}
static unsigned int check_freqs(const cpumask_t *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(drv_data, policy->cpu);
struct acpi_processor_performance *perf;
struct cpufreq_freqs freqs;
cpumask_t online_policy_cpus;
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;
dprintk("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))
return -ENODEV;
#ifdef CONFIG_HOTPLUG_CPU
/* cpufreq holds the hotplug lock, so we are safe from here on */
cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
#else
online_policy_cpus = policy->cpus;
#endif
next_perf_state = data->freq_table[next_state].index;
if (perf->state == next_perf_state) {
if (unlikely(data->resume)) {
dprintk("Called after resume, resetting to P%d\n",
next_perf_state);
data->resume = 0;
} else {
dprintk("Already at target state (P%d)\n",
next_perf_state);
return 0;
}
}
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:
return -ENODEV;
}
cpus_clear(cmd.mask);
if (policy->shared_type != CPUFREQ_SHARED_TYPE_ANY)
cmd.mask = online_policy_cpus;
else
cpu_set(policy->cpu, cmd.mask);
freqs.old = perf->states[perf->state].core_frequency * 1000;
freqs.new = data->freq_table[next_state].frequency;
for_each_cpu_mask_nr(i, cmd.mask) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
}
drv_write(&cmd);
if (acpi_pstate_strict) {
if (!check_freqs(&cmd.mask, freqs.new, data)) {
dprintk("acpi_cpufreq_target failed (%d)\n",
policy->cpu);
return -EAGAIN;
}
}
for_each_cpu_mask_nr(i, cmd.mask) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}
perf->state = next_perf_state;
return result;
}
static int acpi_cpufreq_verify(struct cpufreq_policy *policy)
{
struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
dprintk("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;
}
}
/*
* 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)
{
dprintk("acpi_cpufreq_early_init\n");
acpi_perf_data = alloc_percpu(struct acpi_processor_performance);
if (!acpi_perf_data) {
dprintk("Memory allocation error for acpi_perf_data.\n");
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"),
},
},
{ }
};
#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;
dprintk("acpi_cpufreq_cpu_init\n");
data = kzalloc(sizeof(struct acpi_cpufreq_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->acpi_data = percpu_ptr(acpi_perf_data, cpu);
per_cpu(drv_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) {
policy->cpus = perf->shared_cpu_map;
}
policy->related_cpus = perf->shared_cpu_map;
#ifdef CONFIG_SMP
dmi_check_system(sw_any_bug_dmi_table);
if (bios_with_sw_any_bug && cpus_weight(policy->cpus) == 1) {
policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
policy->cpus = per_cpu(cpu_core_map, cpu);
}
#endif
/* capability check */
if (perf->state_count <= 1) {
dprintk("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:
dprintk("SYSTEM IO addr space\n");
data->cpu_feature = SYSTEM_IO_CAPABLE;
break;
case ACPI_ADR_SPACE_FIXED_HARDWARE:
dprintk("HARDWARE addr space\n");
if (!check_est_cpu(cpu)) {
result = -ENODEV;
goto err_unreg;
}
data->cpu_feature = SYSTEM_INTEL_MSR_CAPABLE;
break;
default:
dprintk("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;
}
data->max_freq = perf->states[0].core_frequency * 1000;
/* 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;
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 (c->x86_vendor == X86_VENDOR_INTEL && c->cpuid_level >= 6) {
unsigned int ecx;
ecx = cpuid_ecx(6);
if (ecx & CPUID_6_ECX_APERFMPERF_CAPABILITY)
acpi_cpufreq_driver.getavg = get_measured_perf;
}
dprintk("CPU%u - ACPI performance management activated.\n", cpu);
for (i = 0; i < perf->state_count; i++)
dprintk(" %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(drv_data, cpu) = NULL;
return result;
}
static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
dprintk("acpi_cpufreq_cpu_exit\n");
if (data) {
cpufreq_frequency_table_put_attr(policy->cpu);
per_cpu(drv_data, policy->cpu) = NULL;
acpi_processor_unregister_performance(data->acpi_data,
policy->cpu);
kfree(data);
}
return 0;
}
static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
{
struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
dprintk("acpi_cpufreq_resume\n");
data->resume = 1;
return 0;
}
static struct freq_attr *acpi_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static struct cpufreq_driver acpi_cpufreq_driver = {
.verify = acpi_cpufreq_verify,
.target = acpi_cpufreq_target,
.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;
dprintk("acpi_cpufreq_init\n");
ret = acpi_cpufreq_early_init();
if (ret)
return ret;
ret = cpufreq_register_driver(&acpi_cpufreq_driver);
if (ret)
free_percpu(acpi_perf_data);
return ret;
}
static void __exit acpi_cpufreq_exit(void)
{
dprintk("acpi_cpufreq_exit\n");
cpufreq_unregister_driver(&acpi_cpufreq_driver);
free_percpu(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");