2 * acpi-cpufreq.c - ACPI Processor P-States Driver ($Revision: 1.4 $)
4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6 * Copyright (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
7 * Copyright (C) 2006 Denis Sadykov <denis.m.sadykov@intel.com>
9 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or (at
14 * your option) any later version.
16 * This program is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
21 * You should have received a copy of the GNU General Public License along
22 * with this program; if not, write to the Free Software Foundation, Inc.,
23 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
25 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/init.h>
31 #include <linux/smp.h>
32 #include <linux/sched.h>
33 #include <linux/cpufreq.h>
34 #include <linux/compiler.h>
35 #include <linux/dmi.h>
36 #include <linux/ftrace.h>
38 #include <linux/acpi.h>
39 #include <acpi/processor.h>
43 #include <asm/processor.h>
44 #include <asm/cpufeature.h>
45 #include <asm/delay.h>
46 #include <asm/uaccess.h>
48 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
50 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
51 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
52 MODULE_LICENSE("GPL");
55 UNDEFINED_CAPABLE
= 0,
56 SYSTEM_INTEL_MSR_CAPABLE
,
60 #define INTEL_MSR_RANGE (0xffff)
61 #define CPUID_6_ECX_APERFMPERF_CAPABILITY (0x1)
63 struct acpi_cpufreq_data
{
64 struct acpi_processor_performance
*acpi_data
;
65 struct cpufreq_frequency_table
*freq_table
;
66 unsigned int max_freq
;
68 unsigned int cpu_feature
;
71 static DEFINE_PER_CPU(struct acpi_cpufreq_data
*, drv_data
);
73 /* acpi_perf_data is a pointer to percpu data. */
74 static struct acpi_processor_performance
*acpi_perf_data
;
76 static struct cpufreq_driver acpi_cpufreq_driver
;
78 static unsigned int acpi_pstate_strict
;
80 static int check_est_cpu(unsigned int cpuid
)
82 struct cpuinfo_x86
*cpu
= &cpu_data(cpuid
);
84 if (cpu
->x86_vendor
!= X86_VENDOR_INTEL
||
85 !cpu_has(cpu
, X86_FEATURE_EST
))
91 static unsigned extract_io(u32 value
, struct acpi_cpufreq_data
*data
)
93 struct acpi_processor_performance
*perf
;
96 perf
= data
->acpi_data
;
98 for (i
=0; i
<perf
->state_count
; i
++) {
99 if (value
== perf
->states
[i
].status
)
100 return data
->freq_table
[i
].frequency
;
105 static unsigned extract_msr(u32 msr
, struct acpi_cpufreq_data
*data
)
108 struct acpi_processor_performance
*perf
;
110 msr
&= INTEL_MSR_RANGE
;
111 perf
= data
->acpi_data
;
113 for (i
=0; data
->freq_table
[i
].frequency
!= CPUFREQ_TABLE_END
; i
++) {
114 if (msr
== perf
->states
[data
->freq_table
[i
].index
].status
)
115 return data
->freq_table
[i
].frequency
;
117 return data
->freq_table
[0].frequency
;
120 static unsigned extract_freq(u32 val
, struct acpi_cpufreq_data
*data
)
122 switch (data
->cpu_feature
) {
123 case SYSTEM_INTEL_MSR_CAPABLE
:
124 return extract_msr(val
, data
);
125 case SYSTEM_IO_CAPABLE
:
126 return extract_io(val
, data
);
153 static void do_drv_read(struct drv_cmd
*cmd
)
158 case SYSTEM_INTEL_MSR_CAPABLE
:
159 rdmsr(cmd
->addr
.msr
.reg
, cmd
->val
, h
);
161 case SYSTEM_IO_CAPABLE
:
162 acpi_os_read_port((acpi_io_address
)cmd
->addr
.io
.port
,
164 (u32
)cmd
->addr
.io
.bit_width
);
171 static void do_drv_write(struct drv_cmd
*cmd
)
176 case SYSTEM_INTEL_MSR_CAPABLE
:
177 rdmsr(cmd
->addr
.msr
.reg
, lo
, hi
);
178 lo
= (lo
& ~INTEL_MSR_RANGE
) | (cmd
->val
& INTEL_MSR_RANGE
);
179 wrmsr(cmd
->addr
.msr
.reg
, lo
, hi
);
181 case SYSTEM_IO_CAPABLE
:
182 acpi_os_write_port((acpi_io_address
)cmd
->addr
.io
.port
,
184 (u32
)cmd
->addr
.io
.bit_width
);
191 static void drv_read(struct drv_cmd
*cmd
)
193 cpumask_t saved_mask
= current
->cpus_allowed
;
196 set_cpus_allowed_ptr(current
, cmd
->mask
);
198 set_cpus_allowed_ptr(current
, &saved_mask
);
201 static void drv_write(struct drv_cmd
*cmd
)
203 cpumask_t saved_mask
= current
->cpus_allowed
;
206 for_each_cpu(i
, cmd
->mask
) {
207 set_cpus_allowed_ptr(current
, cpumask_of(i
));
211 set_cpus_allowed_ptr(current
, &saved_mask
);
215 static u32
get_cur_val(const struct cpumask
*mask
)
217 struct acpi_processor_performance
*perf
;
220 if (unlikely(cpumask_empty(mask
)))
223 switch (per_cpu(drv_data
, cpumask_first(mask
))->cpu_feature
) {
224 case SYSTEM_INTEL_MSR_CAPABLE
:
225 cmd
.type
= SYSTEM_INTEL_MSR_CAPABLE
;
226 cmd
.addr
.msr
.reg
= MSR_IA32_PERF_STATUS
;
228 case SYSTEM_IO_CAPABLE
:
229 cmd
.type
= SYSTEM_IO_CAPABLE
;
230 perf
= per_cpu(drv_data
, cpumask_first(mask
))->acpi_data
;
231 cmd
.addr
.io
.port
= perf
->control_register
.address
;
232 cmd
.addr
.io
.bit_width
= perf
->control_register
.bit_width
;
238 cpumask_copy(cmd
.mask
, mask
);
242 dprintk("get_cur_val = %u\n", cmd
.val
);
254 } aperf_cur
, mperf_cur
;
258 static long read_measured_perf_ctrs(void *_cur
)
260 struct perf_cur
*cur
= _cur
;
262 rdmsr(MSR_IA32_APERF
, cur
->aperf_cur
.split
.lo
, cur
->aperf_cur
.split
.hi
);
263 rdmsr(MSR_IA32_MPERF
, cur
->mperf_cur
.split
.lo
, cur
->mperf_cur
.split
.hi
);
265 wrmsr(MSR_IA32_APERF
, 0, 0);
266 wrmsr(MSR_IA32_MPERF
, 0, 0);
272 * Return the measured active (C0) frequency on this CPU since last call
275 * Return: Average CPU frequency in terms of max frequency (zero on error)
277 * We use IA32_MPERF and IA32_APERF MSRs to get the measured performance
278 * over a period of time, while CPU is in C0 state.
279 * IA32_MPERF counts at the rate of max advertised frequency
280 * IA32_APERF counts at the rate of actual CPU frequency
281 * Only IA32_APERF/IA32_MPERF ratio is architecturally defined and
282 * no meaning should be associated with absolute values of these MSRs.
284 static unsigned int get_measured_perf(struct cpufreq_policy
*policy
,
288 unsigned int perf_percent
;
291 if (!work_on_cpu(cpu
, read_measured_perf_ctrs
, &cur
))
296 * We dont want to do 64 bit divide with 32 bit kernel
297 * Get an approximate value. Return failure in case we cannot get
298 * an approximate value.
300 if (unlikely(cur
.aperf_cur
.split
.hi
|| cur
.mperf_cur
.split
.hi
)) {
304 h
= max_t(u32
, cur
.aperf_cur
.split
.hi
, cur
.mperf_cur
.split
.hi
);
305 shift_count
= fls(h
);
307 cur
.aperf_cur
.whole
>>= shift_count
;
308 cur
.mperf_cur
.whole
>>= shift_count
;
311 if (((unsigned long)(-1) / 100) < cur
.aperf_cur
.split
.lo
) {
313 cur
.aperf_cur
.split
.lo
>>= shift_count
;
314 cur
.mperf_cur
.split
.lo
>>= shift_count
;
317 if (cur
.aperf_cur
.split
.lo
&& cur
.mperf_cur
.split
.lo
)
318 perf_percent
= (cur
.aperf_cur
.split
.lo
* 100) /
319 cur
.mperf_cur
.split
.lo
;
324 if (unlikely(((unsigned long)(-1) / 100) < cur
.aperf_cur
.whole
)) {
326 cur
.aperf_cur
.whole
>>= shift_count
;
327 cur
.mperf_cur
.whole
>>= shift_count
;
330 if (cur
.aperf_cur
.whole
&& cur
.mperf_cur
.whole
)
331 perf_percent
= (cur
.aperf_cur
.whole
* 100) /
338 retval
= per_cpu(drv_data
, policy
->cpu
)->max_freq
* perf_percent
/ 100;
343 static unsigned int get_cur_freq_on_cpu(unsigned int cpu
)
345 struct acpi_cpufreq_data
*data
= per_cpu(drv_data
, cpu
);
347 unsigned int cached_freq
;
349 dprintk("get_cur_freq_on_cpu (%d)\n", cpu
);
351 if (unlikely(data
== NULL
||
352 data
->acpi_data
== NULL
|| data
->freq_table
== NULL
)) {
356 cached_freq
= data
->freq_table
[data
->acpi_data
->state
].frequency
;
357 freq
= extract_freq(get_cur_val(cpumask_of(cpu
)), data
);
358 if (freq
!= cached_freq
) {
360 * The dreaded BIOS frequency change behind our back.
361 * Force set the frequency on next target call.
366 dprintk("cur freq = %u\n", freq
);
371 static unsigned int check_freqs(const cpumask_t
*mask
, unsigned int freq
,
372 struct acpi_cpufreq_data
*data
)
374 unsigned int cur_freq
;
377 for (i
=0; i
<100; i
++) {
378 cur_freq
= extract_freq(get_cur_val(mask
), data
);
379 if (cur_freq
== freq
)
386 static int acpi_cpufreq_target(struct cpufreq_policy
*policy
,
387 unsigned int target_freq
, unsigned int relation
)
389 struct acpi_cpufreq_data
*data
= per_cpu(drv_data
, policy
->cpu
);
390 struct acpi_processor_performance
*perf
;
391 struct cpufreq_freqs freqs
;
393 unsigned int next_state
= 0; /* Index into freq_table */
394 unsigned int next_perf_state
= 0; /* Index into perf table */
397 struct power_trace it
;
399 dprintk("acpi_cpufreq_target %d (%d)\n", target_freq
, policy
->cpu
);
401 if (unlikely(data
== NULL
||
402 data
->acpi_data
== NULL
|| data
->freq_table
== NULL
)) {
406 if (unlikely(!alloc_cpumask_var(&cmd
.mask
, GFP_KERNEL
)))
409 perf
= data
->acpi_data
;
410 result
= cpufreq_frequency_table_target(policy
,
413 relation
, &next_state
);
414 if (unlikely(result
)) {
419 next_perf_state
= data
->freq_table
[next_state
].index
;
420 if (perf
->state
== next_perf_state
) {
421 if (unlikely(data
->resume
)) {
422 dprintk("Called after resume, resetting to P%d\n",
426 dprintk("Already at target state (P%d)\n",
432 trace_power_mark(&it
, POWER_PSTATE
, next_perf_state
);
434 switch (data
->cpu_feature
) {
435 case SYSTEM_INTEL_MSR_CAPABLE
:
436 cmd
.type
= SYSTEM_INTEL_MSR_CAPABLE
;
437 cmd
.addr
.msr
.reg
= MSR_IA32_PERF_CTL
;
438 cmd
.val
= (u32
) perf
->states
[next_perf_state
].control
;
440 case SYSTEM_IO_CAPABLE
:
441 cmd
.type
= SYSTEM_IO_CAPABLE
;
442 cmd
.addr
.io
.port
= perf
->control_register
.address
;
443 cmd
.addr
.io
.bit_width
= perf
->control_register
.bit_width
;
444 cmd
.val
= (u32
) perf
->states
[next_perf_state
].control
;
451 /* cpufreq holds the hotplug lock, so we are safe from here on */
452 if (policy
->shared_type
!= CPUFREQ_SHARED_TYPE_ANY
)
453 cpumask_and(cmd
.mask
, cpu_online_mask
, policy
->cpus
);
455 cpumask_copy(cmd
.mask
, cpumask_of(policy
->cpu
));
457 freqs
.old
= perf
->states
[perf
->state
].core_frequency
* 1000;
458 freqs
.new = data
->freq_table
[next_state
].frequency
;
459 for_each_cpu(i
, cmd
.mask
) {
461 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
466 if (acpi_pstate_strict
) {
467 if (!check_freqs(cmd
.mask
, freqs
.new, data
)) {
468 dprintk("acpi_cpufreq_target failed (%d)\n",
475 for_each_cpu(i
, cmd
.mask
) {
477 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
479 perf
->state
= next_perf_state
;
482 free_cpumask_var(cmd
.mask
);
486 static int acpi_cpufreq_verify(struct cpufreq_policy
*policy
)
488 struct acpi_cpufreq_data
*data
= per_cpu(drv_data
, policy
->cpu
);
490 dprintk("acpi_cpufreq_verify\n");
492 return cpufreq_frequency_table_verify(policy
, data
->freq_table
);
496 acpi_cpufreq_guess_freq(struct acpi_cpufreq_data
*data
, unsigned int cpu
)
498 struct acpi_processor_performance
*perf
= data
->acpi_data
;
501 /* search the closest match to cpu_khz */
504 unsigned long freqn
= perf
->states
[0].core_frequency
* 1000;
506 for (i
=0; i
<(perf
->state_count
-1); i
++) {
508 freqn
= perf
->states
[i
+1].core_frequency
* 1000;
509 if ((2 * cpu_khz
) > (freqn
+ freq
)) {
514 perf
->state
= perf
->state_count
-1;
517 /* assume CPU is at P0... */
519 return perf
->states
[0].core_frequency
* 1000;
523 static void free_acpi_perf_data(void)
527 /* Freeing a NULL pointer is OK, and alloc_percpu zeroes. */
528 for_each_possible_cpu(i
)
529 free_cpumask_var(per_cpu_ptr(acpi_perf_data
, i
)
531 free_percpu(acpi_perf_data
);
535 * acpi_cpufreq_early_init - initialize ACPI P-States library
537 * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
538 * in order to determine correct frequency and voltage pairings. We can
539 * do _PDC and _PSD and find out the processor dependency for the
540 * actual init that will happen later...
542 static int __init
acpi_cpufreq_early_init(void)
545 dprintk("acpi_cpufreq_early_init\n");
547 acpi_perf_data
= alloc_percpu(struct acpi_processor_performance
);
548 if (!acpi_perf_data
) {
549 dprintk("Memory allocation error for acpi_perf_data.\n");
552 for_each_possible_cpu(i
) {
553 if (!alloc_cpumask_var_node(
554 &per_cpu_ptr(acpi_perf_data
, i
)->shared_cpu_map
,
555 GFP_KERNEL
, cpu_to_node(i
))) {
557 /* Freeing a NULL pointer is OK: alloc_percpu zeroes. */
558 free_acpi_perf_data();
563 /* Do initialization in ACPI core */
564 acpi_processor_preregister_performance(acpi_perf_data
);
570 * Some BIOSes do SW_ANY coordination internally, either set it up in hw
571 * or do it in BIOS firmware and won't inform about it to OS. If not
572 * detected, this has a side effect of making CPU run at a different speed
573 * than OS intended it to run at. Detect it and handle it cleanly.
575 static int bios_with_sw_any_bug
;
577 static int sw_any_bug_found(const struct dmi_system_id
*d
)
579 bios_with_sw_any_bug
= 1;
583 static const struct dmi_system_id sw_any_bug_dmi_table
[] = {
585 .callback
= sw_any_bug_found
,
586 .ident
= "Supermicro Server X6DLP",
588 DMI_MATCH(DMI_SYS_VENDOR
, "Supermicro"),
589 DMI_MATCH(DMI_BIOS_VERSION
, "080010"),
590 DMI_MATCH(DMI_PRODUCT_NAME
, "X6DLP"),
597 static int acpi_cpufreq_cpu_init(struct cpufreq_policy
*policy
)
600 unsigned int valid_states
= 0;
601 unsigned int cpu
= policy
->cpu
;
602 struct acpi_cpufreq_data
*data
;
603 unsigned int result
= 0;
604 struct cpuinfo_x86
*c
= &cpu_data(policy
->cpu
);
605 struct acpi_processor_performance
*perf
;
607 dprintk("acpi_cpufreq_cpu_init\n");
609 data
= kzalloc(sizeof(struct acpi_cpufreq_data
), GFP_KERNEL
);
613 data
->acpi_data
= percpu_ptr(acpi_perf_data
, cpu
);
614 per_cpu(drv_data
, cpu
) = data
;
616 if (cpu_has(c
, X86_FEATURE_CONSTANT_TSC
))
617 acpi_cpufreq_driver
.flags
|= CPUFREQ_CONST_LOOPS
;
619 result
= acpi_processor_register_performance(data
->acpi_data
, cpu
);
623 perf
= data
->acpi_data
;
624 policy
->shared_type
= perf
->shared_type
;
627 * Will let policy->cpus know about dependency only when software
628 * coordination is required.
630 if (policy
->shared_type
== CPUFREQ_SHARED_TYPE_ALL
||
631 policy
->shared_type
== CPUFREQ_SHARED_TYPE_ANY
) {
632 cpumask_copy(policy
->cpus
, perf
->shared_cpu_map
);
634 cpumask_copy(policy
->related_cpus
, perf
->shared_cpu_map
);
637 dmi_check_system(sw_any_bug_dmi_table
);
638 if (bios_with_sw_any_bug
&& cpumask_weight(policy
->cpus
) == 1) {
639 policy
->shared_type
= CPUFREQ_SHARED_TYPE_ALL
;
640 cpumask_copy(policy
->cpus
, cpu_core_mask(cpu
));
644 /* capability check */
645 if (perf
->state_count
<= 1) {
646 dprintk("No P-States\n");
651 if (perf
->control_register
.space_id
!= perf
->status_register
.space_id
) {
656 switch (perf
->control_register
.space_id
) {
657 case ACPI_ADR_SPACE_SYSTEM_IO
:
658 dprintk("SYSTEM IO addr space\n");
659 data
->cpu_feature
= SYSTEM_IO_CAPABLE
;
661 case ACPI_ADR_SPACE_FIXED_HARDWARE
:
662 dprintk("HARDWARE addr space\n");
663 if (!check_est_cpu(cpu
)) {
667 data
->cpu_feature
= SYSTEM_INTEL_MSR_CAPABLE
;
670 dprintk("Unknown addr space %d\n",
671 (u32
) (perf
->control_register
.space_id
));
676 data
->freq_table
= kmalloc(sizeof(struct cpufreq_frequency_table
) *
677 (perf
->state_count
+1), GFP_KERNEL
);
678 if (!data
->freq_table
) {
683 /* detect transition latency */
684 policy
->cpuinfo
.transition_latency
= 0;
685 for (i
=0; i
<perf
->state_count
; i
++) {
686 if ((perf
->states
[i
].transition_latency
* 1000) >
687 policy
->cpuinfo
.transition_latency
)
688 policy
->cpuinfo
.transition_latency
=
689 perf
->states
[i
].transition_latency
* 1000;
692 data
->max_freq
= perf
->states
[0].core_frequency
* 1000;
694 for (i
=0; i
<perf
->state_count
; i
++) {
695 if (i
>0 && perf
->states
[i
].core_frequency
>=
696 data
->freq_table
[valid_states
-1].frequency
/ 1000)
699 data
->freq_table
[valid_states
].index
= i
;
700 data
->freq_table
[valid_states
].frequency
=
701 perf
->states
[i
].core_frequency
* 1000;
704 data
->freq_table
[valid_states
].frequency
= CPUFREQ_TABLE_END
;
707 result
= cpufreq_frequency_table_cpuinfo(policy
, data
->freq_table
);
711 switch (perf
->control_register
.space_id
) {
712 case ACPI_ADR_SPACE_SYSTEM_IO
:
713 /* Current speed is unknown and not detectable by IO port */
714 policy
->cur
= acpi_cpufreq_guess_freq(data
, policy
->cpu
);
716 case ACPI_ADR_SPACE_FIXED_HARDWARE
:
717 acpi_cpufreq_driver
.get
= get_cur_freq_on_cpu
;
718 policy
->cur
= get_cur_freq_on_cpu(cpu
);
724 /* notify BIOS that we exist */
725 acpi_processor_notify_smm(THIS_MODULE
);
727 /* Check for APERF/MPERF support in hardware */
728 if (c
->x86_vendor
== X86_VENDOR_INTEL
&& c
->cpuid_level
>= 6) {
731 if (ecx
& CPUID_6_ECX_APERFMPERF_CAPABILITY
)
732 acpi_cpufreq_driver
.getavg
= get_measured_perf
;
735 dprintk("CPU%u - ACPI performance management activated.\n", cpu
);
736 for (i
= 0; i
< perf
->state_count
; i
++)
737 dprintk(" %cP%d: %d MHz, %d mW, %d uS\n",
738 (i
== perf
->state
? '*' : ' '), i
,
739 (u32
) perf
->states
[i
].core_frequency
,
740 (u32
) perf
->states
[i
].power
,
741 (u32
) perf
->states
[i
].transition_latency
);
743 cpufreq_frequency_table_get_attr(data
->freq_table
, policy
->cpu
);
746 * the first call to ->target() should result in us actually
747 * writing something to the appropriate registers.
754 kfree(data
->freq_table
);
756 acpi_processor_unregister_performance(perf
, cpu
);
759 per_cpu(drv_data
, cpu
) = NULL
;
764 static int acpi_cpufreq_cpu_exit(struct cpufreq_policy
*policy
)
766 struct acpi_cpufreq_data
*data
= per_cpu(drv_data
, policy
->cpu
);
768 dprintk("acpi_cpufreq_cpu_exit\n");
771 cpufreq_frequency_table_put_attr(policy
->cpu
);
772 per_cpu(drv_data
, policy
->cpu
) = NULL
;
773 acpi_processor_unregister_performance(data
->acpi_data
,
781 static int acpi_cpufreq_resume(struct cpufreq_policy
*policy
)
783 struct acpi_cpufreq_data
*data
= per_cpu(drv_data
, policy
->cpu
);
785 dprintk("acpi_cpufreq_resume\n");
792 static struct freq_attr
*acpi_cpufreq_attr
[] = {
793 &cpufreq_freq_attr_scaling_available_freqs
,
797 static struct cpufreq_driver acpi_cpufreq_driver
= {
798 .verify
= acpi_cpufreq_verify
,
799 .target
= acpi_cpufreq_target
,
800 .init
= acpi_cpufreq_cpu_init
,
801 .exit
= acpi_cpufreq_cpu_exit
,
802 .resume
= acpi_cpufreq_resume
,
803 .name
= "acpi-cpufreq",
804 .owner
= THIS_MODULE
,
805 .attr
= acpi_cpufreq_attr
,
808 static int __init
acpi_cpufreq_init(void)
815 dprintk("acpi_cpufreq_init\n");
817 ret
= acpi_cpufreq_early_init();
821 ret
= cpufreq_register_driver(&acpi_cpufreq_driver
);
823 free_acpi_perf_data();
828 static void __exit
acpi_cpufreq_exit(void)
830 dprintk("acpi_cpufreq_exit\n");
832 cpufreq_unregister_driver(&acpi_cpufreq_driver
);
834 free_percpu(acpi_perf_data
);
837 module_param(acpi_pstate_strict
, uint
, 0644);
838 MODULE_PARM_DESC(acpi_pstate_strict
,
839 "value 0 or non-zero. non-zero -> strict ACPI checks are "
840 "performed during frequency changes.");
842 late_initcall(acpi_cpufreq_init
);
843 module_exit(acpi_cpufreq_exit
);
845 MODULE_ALIAS("acpi");