Merge git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq
[linux-2.6.git] / arch / x86 / kernel / cpu / cpufreq / acpi-cpufreq.c
1 /*
2  * acpi-cpufreq.c - ACPI Processor P-States Driver ($Revision: 1.4 $)
3  *
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>
8  *
9  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
10  *
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.
15  *
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.
20  *
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.
24  *
25  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
26  */
27
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
37 #include <linux/acpi.h>
38 #include <acpi/processor.h>
39
40 #include <asm/io.h>
41 #include <asm/msr.h>
42 #include <asm/processor.h>
43 #include <asm/cpufeature.h>
44 #include <asm/delay.h>
45 #include <asm/uaccess.h>
46
47 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
48
49 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
50 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
51 MODULE_LICENSE("GPL");
52
53 enum {
54         UNDEFINED_CAPABLE = 0,
55         SYSTEM_INTEL_MSR_CAPABLE,
56         SYSTEM_IO_CAPABLE,
57 };
58
59 #define INTEL_MSR_RANGE         (0xffff)
60 #define CPUID_6_ECX_APERFMPERF_CAPABILITY       (0x1)
61
62 struct acpi_cpufreq_data {
63         struct acpi_processor_performance *acpi_data;
64         struct cpufreq_frequency_table *freq_table;
65         unsigned int max_freq;
66         unsigned int resume;
67         unsigned int cpu_feature;
68 };
69
70 static DEFINE_PER_CPU(struct acpi_cpufreq_data *, drv_data);
71
72 /* acpi_perf_data is a pointer to percpu data. */
73 static struct acpi_processor_performance *acpi_perf_data;
74
75 static struct cpufreq_driver acpi_cpufreq_driver;
76
77 static unsigned int acpi_pstate_strict;
78
79 static int check_est_cpu(unsigned int cpuid)
80 {
81         struct cpuinfo_x86 *cpu = &cpu_data(cpuid);
82
83         if (cpu->x86_vendor != X86_VENDOR_INTEL ||
84             !cpu_has(cpu, X86_FEATURE_EST))
85                 return 0;
86
87         return 1;
88 }
89
90 static unsigned extract_io(u32 value, struct acpi_cpufreq_data *data)
91 {
92         struct acpi_processor_performance *perf;
93         int i;
94
95         perf = data->acpi_data;
96
97         for (i=0; i<perf->state_count; i++) {
98                 if (value == perf->states[i].status)
99                         return data->freq_table[i].frequency;
100         }
101         return 0;
102 }
103
104 static unsigned extract_msr(u32 msr, struct acpi_cpufreq_data *data)
105 {
106         int i;
107         struct acpi_processor_performance *perf;
108
109         msr &= INTEL_MSR_RANGE;
110         perf = data->acpi_data;
111
112         for (i=0; data->freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
113                 if (msr == perf->states[data->freq_table[i].index].status)
114                         return data->freq_table[i].frequency;
115         }
116         return data->freq_table[0].frequency;
117 }
118
119 static unsigned extract_freq(u32 val, struct acpi_cpufreq_data *data)
120 {
121         switch (data->cpu_feature) {
122         case SYSTEM_INTEL_MSR_CAPABLE:
123                 return extract_msr(val, data);
124         case SYSTEM_IO_CAPABLE:
125                 return extract_io(val, data);
126         default:
127                 return 0;
128         }
129 }
130
131 struct msr_addr {
132         u32 reg;
133 };
134
135 struct io_addr {
136         u16 port;
137         u8 bit_width;
138 };
139
140 typedef union {
141         struct msr_addr msr;
142         struct io_addr io;
143 } drv_addr_union;
144
145 struct drv_cmd {
146         unsigned int type;
147         cpumask_t mask;
148         drv_addr_union addr;
149         u32 val;
150 };
151
152 static void do_drv_read(struct drv_cmd *cmd)
153 {
154         u32 h;
155
156         switch (cmd->type) {
157         case SYSTEM_INTEL_MSR_CAPABLE:
158                 rdmsr(cmd->addr.msr.reg, cmd->val, h);
159                 break;
160         case SYSTEM_IO_CAPABLE:
161                 acpi_os_read_port((acpi_io_address)cmd->addr.io.port,
162                                 &cmd->val,
163                                 (u32)cmd->addr.io.bit_width);
164                 break;
165         default:
166                 break;
167         }
168 }
169
170 static void do_drv_write(struct drv_cmd *cmd)
171 {
172         u32 lo, hi;
173
174         switch (cmd->type) {
175         case SYSTEM_INTEL_MSR_CAPABLE:
176                 rdmsr(cmd->addr.msr.reg, lo, hi);
177                 lo = (lo & ~INTEL_MSR_RANGE) | (cmd->val & INTEL_MSR_RANGE);
178                 wrmsr(cmd->addr.msr.reg, lo, hi);
179                 break;
180         case SYSTEM_IO_CAPABLE:
181                 acpi_os_write_port((acpi_io_address)cmd->addr.io.port,
182                                 cmd->val,
183                                 (u32)cmd->addr.io.bit_width);
184                 break;
185         default:
186                 break;
187         }
188 }
189
190 static void drv_read(struct drv_cmd *cmd)
191 {
192         cpumask_t saved_mask = current->cpus_allowed;
193         cmd->val = 0;
194
195         set_cpus_allowed_ptr(current, &cmd->mask);
196         do_drv_read(cmd);
197         set_cpus_allowed_ptr(current, &saved_mask);
198 }
199
200 static void drv_write(struct drv_cmd *cmd)
201 {
202         cpumask_t saved_mask = current->cpus_allowed;
203         unsigned int i;
204
205         for_each_cpu_mask(i, cmd->mask) {
206                 set_cpus_allowed_ptr(current, &cpumask_of_cpu(i));
207                 do_drv_write(cmd);
208         }
209
210         set_cpus_allowed_ptr(current, &saved_mask);
211         return;
212 }
213
214 static u32 get_cur_val(const cpumask_t *mask)
215 {
216         struct acpi_processor_performance *perf;
217         struct drv_cmd cmd;
218
219         if (unlikely(cpus_empty(*mask)))
220                 return 0;
221
222         switch (per_cpu(drv_data, first_cpu(*mask))->cpu_feature) {
223         case SYSTEM_INTEL_MSR_CAPABLE:
224                 cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
225                 cmd.addr.msr.reg = MSR_IA32_PERF_STATUS;
226                 break;
227         case SYSTEM_IO_CAPABLE:
228                 cmd.type = SYSTEM_IO_CAPABLE;
229                 perf = per_cpu(drv_data, first_cpu(*mask))->acpi_data;
230                 cmd.addr.io.port = perf->control_register.address;
231                 cmd.addr.io.bit_width = perf->control_register.bit_width;
232                 break;
233         default:
234                 return 0;
235         }
236
237         cmd.mask = *mask;
238
239         drv_read(&cmd);
240
241         dprintk("get_cur_val = %u\n", cmd.val);
242
243         return cmd.val;
244 }
245
246 /*
247  * Return the measured active (C0) frequency on this CPU since last call
248  * to this function.
249  * Input: cpu number
250  * Return: Average CPU frequency in terms of max frequency (zero on error)
251  *
252  * We use IA32_MPERF and IA32_APERF MSRs to get the measured performance
253  * over a period of time, while CPU is in C0 state.
254  * IA32_MPERF counts at the rate of max advertised frequency
255  * IA32_APERF counts at the rate of actual CPU frequency
256  * Only IA32_APERF/IA32_MPERF ratio is architecturally defined and
257  * no meaning should be associated with absolute values of these MSRs.
258  */
259 static unsigned int get_measured_perf(unsigned int cpu)
260 {
261         union {
262                 struct {
263                         u32 lo;
264                         u32 hi;
265                 } split;
266                 u64 whole;
267         } aperf_cur, mperf_cur;
268
269         cpumask_t saved_mask;
270         unsigned int perf_percent;
271         unsigned int retval;
272
273         saved_mask = current->cpus_allowed;
274         set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
275         if (get_cpu() != cpu) {
276                 /* We were not able to run on requested processor */
277                 put_cpu();
278                 return 0;
279         }
280
281         rdmsr(MSR_IA32_APERF, aperf_cur.split.lo, aperf_cur.split.hi);
282         rdmsr(MSR_IA32_MPERF, mperf_cur.split.lo, mperf_cur.split.hi);
283
284         wrmsr(MSR_IA32_APERF, 0,0);
285         wrmsr(MSR_IA32_MPERF, 0,0);
286
287 #ifdef __i386__
288         /*
289          * We dont want to do 64 bit divide with 32 bit kernel
290          * Get an approximate value. Return failure in case we cannot get
291          * an approximate value.
292          */
293         if (unlikely(aperf_cur.split.hi || mperf_cur.split.hi)) {
294                 int shift_count;
295                 u32 h;
296
297                 h = max_t(u32, aperf_cur.split.hi, mperf_cur.split.hi);
298                 shift_count = fls(h);
299
300                 aperf_cur.whole >>= shift_count;
301                 mperf_cur.whole >>= shift_count;
302         }
303
304         if (((unsigned long)(-1) / 100) < aperf_cur.split.lo) {
305                 int shift_count = 7;
306                 aperf_cur.split.lo >>= shift_count;
307                 mperf_cur.split.lo >>= shift_count;
308         }
309
310         if (aperf_cur.split.lo && mperf_cur.split.lo)
311                 perf_percent = (aperf_cur.split.lo * 100) / mperf_cur.split.lo;
312         else
313                 perf_percent = 0;
314
315 #else
316         if (unlikely(((unsigned long)(-1) / 100) < aperf_cur.whole)) {
317                 int shift_count = 7;
318                 aperf_cur.whole >>= shift_count;
319                 mperf_cur.whole >>= shift_count;
320         }
321
322         if (aperf_cur.whole && mperf_cur.whole)
323                 perf_percent = (aperf_cur.whole * 100) / mperf_cur.whole;
324         else
325                 perf_percent = 0;
326
327 #endif
328
329         retval = per_cpu(drv_data, cpu)->max_freq * perf_percent / 100;
330
331         put_cpu();
332         set_cpus_allowed_ptr(current, &saved_mask);
333
334         dprintk("cpu %d: performance percent %d\n", cpu, perf_percent);
335         return retval;
336 }
337
338 static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
339 {
340         struct acpi_cpufreq_data *data = per_cpu(drv_data, cpu);
341         unsigned int freq;
342         unsigned int cached_freq;
343
344         dprintk("get_cur_freq_on_cpu (%d)\n", cpu);
345
346         if (unlikely(data == NULL ||
347                      data->acpi_data == NULL || data->freq_table == NULL)) {
348                 return 0;
349         }
350
351         cached_freq = data->freq_table[data->acpi_data->state].frequency;
352         freq = extract_freq(get_cur_val(&cpumask_of_cpu(cpu)), data);
353         if (freq != cached_freq) {
354                 /*
355                  * The dreaded BIOS frequency change behind our back.
356                  * Force set the frequency on next target call.
357                  */
358                 data->resume = 1;
359         }
360
361         dprintk("cur freq = %u\n", freq);
362
363         return freq;
364 }
365
366 static unsigned int check_freqs(const cpumask_t *mask, unsigned int freq,
367                                 struct acpi_cpufreq_data *data)
368 {
369         unsigned int cur_freq;
370         unsigned int i;
371
372         for (i=0; i<100; i++) {
373                 cur_freq = extract_freq(get_cur_val(mask), data);
374                 if (cur_freq == freq)
375                         return 1;
376                 udelay(10);
377         }
378         return 0;
379 }
380
381 static int acpi_cpufreq_target(struct cpufreq_policy *policy,
382                                unsigned int target_freq, unsigned int relation)
383 {
384         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
385         struct acpi_processor_performance *perf;
386         struct cpufreq_freqs freqs;
387         cpumask_t online_policy_cpus;
388         struct drv_cmd cmd;
389         unsigned int next_state = 0; /* Index into freq_table */
390         unsigned int next_perf_state = 0; /* Index into perf table */
391         unsigned int i;
392         int result = 0;
393
394         dprintk("acpi_cpufreq_target %d (%d)\n", target_freq, policy->cpu);
395
396         if (unlikely(data == NULL ||
397              data->acpi_data == NULL || data->freq_table == NULL)) {
398                 return -ENODEV;
399         }
400
401         perf = data->acpi_data;
402         result = cpufreq_frequency_table_target(policy,
403                                                 data->freq_table,
404                                                 target_freq,
405                                                 relation, &next_state);
406         if (unlikely(result))
407                 return -ENODEV;
408
409 #ifdef CONFIG_HOTPLUG_CPU
410         /* cpufreq holds the hotplug lock, so we are safe from here on */
411         cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
412 #else
413         online_policy_cpus = policy->cpus;
414 #endif
415
416         next_perf_state = data->freq_table[next_state].index;
417         if (perf->state == next_perf_state) {
418                 if (unlikely(data->resume)) {
419                         dprintk("Called after resume, resetting to P%d\n",
420                                 next_perf_state);
421                         data->resume = 0;
422                 } else {
423                         dprintk("Already at target state (P%d)\n",
424                                 next_perf_state);
425                         return 0;
426                 }
427         }
428
429         switch (data->cpu_feature) {
430         case SYSTEM_INTEL_MSR_CAPABLE:
431                 cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
432                 cmd.addr.msr.reg = MSR_IA32_PERF_CTL;
433                 cmd.val = (u32) perf->states[next_perf_state].control;
434                 break;
435         case SYSTEM_IO_CAPABLE:
436                 cmd.type = SYSTEM_IO_CAPABLE;
437                 cmd.addr.io.port = perf->control_register.address;
438                 cmd.addr.io.bit_width = perf->control_register.bit_width;
439                 cmd.val = (u32) perf->states[next_perf_state].control;
440                 break;
441         default:
442                 return -ENODEV;
443         }
444
445         cpus_clear(cmd.mask);
446
447         if (policy->shared_type != CPUFREQ_SHARED_TYPE_ANY)
448                 cmd.mask = online_policy_cpus;
449         else
450                 cpu_set(policy->cpu, cmd.mask);
451
452         freqs.old = perf->states[perf->state].core_frequency * 1000;
453         freqs.new = data->freq_table[next_state].frequency;
454         for_each_cpu_mask(i, cmd.mask) {
455                 freqs.cpu = i;
456                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
457         }
458
459         drv_write(&cmd);
460
461         if (acpi_pstate_strict) {
462                 if (!check_freqs(&cmd.mask, freqs.new, data)) {
463                         dprintk("acpi_cpufreq_target failed (%d)\n",
464                                 policy->cpu);
465                         return -EAGAIN;
466                 }
467         }
468
469         for_each_cpu_mask(i, cmd.mask) {
470                 freqs.cpu = i;
471                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
472         }
473         perf->state = next_perf_state;
474
475         return result;
476 }
477
478 static int acpi_cpufreq_verify(struct cpufreq_policy *policy)
479 {
480         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
481
482         dprintk("acpi_cpufreq_verify\n");
483
484         return cpufreq_frequency_table_verify(policy, data->freq_table);
485 }
486
487 static unsigned long
488 acpi_cpufreq_guess_freq(struct acpi_cpufreq_data *data, unsigned int cpu)
489 {
490         struct acpi_processor_performance *perf = data->acpi_data;
491
492         if (cpu_khz) {
493                 /* search the closest match to cpu_khz */
494                 unsigned int i;
495                 unsigned long freq;
496                 unsigned long freqn = perf->states[0].core_frequency * 1000;
497
498                 for (i=0; i<(perf->state_count-1); i++) {
499                         freq = freqn;
500                         freqn = perf->states[i+1].core_frequency * 1000;
501                         if ((2 * cpu_khz) > (freqn + freq)) {
502                                 perf->state = i;
503                                 return freq;
504                         }
505                 }
506                 perf->state = perf->state_count-1;
507                 return freqn;
508         } else {
509                 /* assume CPU is at P0... */
510                 perf->state = 0;
511                 return perf->states[0].core_frequency * 1000;
512         }
513 }
514
515 /*
516  * acpi_cpufreq_early_init - initialize ACPI P-States library
517  *
518  * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
519  * in order to determine correct frequency and voltage pairings. We can
520  * do _PDC and _PSD and find out the processor dependency for the
521  * actual init that will happen later...
522  */
523 static int __init acpi_cpufreq_early_init(void)
524 {
525         dprintk("acpi_cpufreq_early_init\n");
526
527         acpi_perf_data = alloc_percpu(struct acpi_processor_performance);
528         if (!acpi_perf_data) {
529                 dprintk("Memory allocation error for acpi_perf_data.\n");
530                 return -ENOMEM;
531         }
532
533         /* Do initialization in ACPI core */
534         acpi_processor_preregister_performance(acpi_perf_data);
535         return 0;
536 }
537
538 #ifdef CONFIG_SMP
539 /*
540  * Some BIOSes do SW_ANY coordination internally, either set it up in hw
541  * or do it in BIOS firmware and won't inform about it to OS. If not
542  * detected, this has a side effect of making CPU run at a different speed
543  * than OS intended it to run at. Detect it and handle it cleanly.
544  */
545 static int bios_with_sw_any_bug;
546
547 static int sw_any_bug_found(const struct dmi_system_id *d)
548 {
549         bios_with_sw_any_bug = 1;
550         return 0;
551 }
552
553 static const struct dmi_system_id sw_any_bug_dmi_table[] = {
554         {
555                 .callback = sw_any_bug_found,
556                 .ident = "Supermicro Server X6DLP",
557                 .matches = {
558                         DMI_MATCH(DMI_SYS_VENDOR, "Supermicro"),
559                         DMI_MATCH(DMI_BIOS_VERSION, "080010"),
560                         DMI_MATCH(DMI_PRODUCT_NAME, "X6DLP"),
561                 },
562         },
563         { }
564 };
565 #endif
566
567 static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
568 {
569         unsigned int i;
570         unsigned int valid_states = 0;
571         unsigned int cpu = policy->cpu;
572         struct acpi_cpufreq_data *data;
573         unsigned int result = 0;
574         struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
575         struct acpi_processor_performance *perf;
576
577         dprintk("acpi_cpufreq_cpu_init\n");
578
579         data = kzalloc(sizeof(struct acpi_cpufreq_data), GFP_KERNEL);
580         if (!data)
581                 return -ENOMEM;
582
583         data->acpi_data = percpu_ptr(acpi_perf_data, cpu);
584         per_cpu(drv_data, cpu) = data;
585
586         if (cpu_has(c, X86_FEATURE_CONSTANT_TSC))
587                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
588
589         result = acpi_processor_register_performance(data->acpi_data, cpu);
590         if (result)
591                 goto err_free;
592
593         perf = data->acpi_data;
594         policy->shared_type = perf->shared_type;
595
596         /*
597          * Will let policy->cpus know about dependency only when software
598          * coordination is required.
599          */
600         if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
601             policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
602                 policy->cpus = perf->shared_cpu_map;
603         }
604         policy->related_cpus = perf->shared_cpu_map;
605
606 #ifdef CONFIG_SMP
607         dmi_check_system(sw_any_bug_dmi_table);
608         if (bios_with_sw_any_bug && cpus_weight(policy->cpus) == 1) {
609                 policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
610                 policy->cpus = per_cpu(cpu_core_map, cpu);
611         }
612 #endif
613
614         /* capability check */
615         if (perf->state_count <= 1) {
616                 dprintk("No P-States\n");
617                 result = -ENODEV;
618                 goto err_unreg;
619         }
620
621         if (perf->control_register.space_id != perf->status_register.space_id) {
622                 result = -ENODEV;
623                 goto err_unreg;
624         }
625
626         switch (perf->control_register.space_id) {
627         case ACPI_ADR_SPACE_SYSTEM_IO:
628                 dprintk("SYSTEM IO addr space\n");
629                 data->cpu_feature = SYSTEM_IO_CAPABLE;
630                 break;
631         case ACPI_ADR_SPACE_FIXED_HARDWARE:
632                 dprintk("HARDWARE addr space\n");
633                 if (!check_est_cpu(cpu)) {
634                         result = -ENODEV;
635                         goto err_unreg;
636                 }
637                 data->cpu_feature = SYSTEM_INTEL_MSR_CAPABLE;
638                 break;
639         default:
640                 dprintk("Unknown addr space %d\n",
641                         (u32) (perf->control_register.space_id));
642                 result = -ENODEV;
643                 goto err_unreg;
644         }
645
646         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
647                     (perf->state_count+1), GFP_KERNEL);
648         if (!data->freq_table) {
649                 result = -ENOMEM;
650                 goto err_unreg;
651         }
652
653         /* detect transition latency */
654         policy->cpuinfo.transition_latency = 0;
655         for (i=0; i<perf->state_count; i++) {
656                 if ((perf->states[i].transition_latency * 1000) >
657                     policy->cpuinfo.transition_latency)
658                         policy->cpuinfo.transition_latency =
659                             perf->states[i].transition_latency * 1000;
660         }
661
662         data->max_freq = perf->states[0].core_frequency * 1000;
663         /* table init */
664         for (i=0; i<perf->state_count; i++) {
665                 if (i>0 && perf->states[i].core_frequency >=
666                     data->freq_table[valid_states-1].frequency / 1000)
667                         continue;
668
669                 data->freq_table[valid_states].index = i;
670                 data->freq_table[valid_states].frequency =
671                     perf->states[i].core_frequency * 1000;
672                 valid_states++;
673         }
674         data->freq_table[valid_states].frequency = CPUFREQ_TABLE_END;
675         perf->state = 0;
676
677         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
678         if (result)
679                 goto err_freqfree;
680
681         switch (perf->control_register.space_id) {
682         case ACPI_ADR_SPACE_SYSTEM_IO:
683                 /* Current speed is unknown and not detectable by IO port */
684                 policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
685                 break;
686         case ACPI_ADR_SPACE_FIXED_HARDWARE:
687                 acpi_cpufreq_driver.get = get_cur_freq_on_cpu;
688                 policy->cur = get_cur_freq_on_cpu(cpu);
689                 break;
690         default:
691                 break;
692         }
693
694         /* notify BIOS that we exist */
695         acpi_processor_notify_smm(THIS_MODULE);
696
697         /* Check for APERF/MPERF support in hardware */
698         if (c->x86_vendor == X86_VENDOR_INTEL && c->cpuid_level >= 6) {
699                 unsigned int ecx;
700                 ecx = cpuid_ecx(6);
701                 if (ecx & CPUID_6_ECX_APERFMPERF_CAPABILITY)
702                         acpi_cpufreq_driver.getavg = get_measured_perf;
703         }
704
705         dprintk("CPU%u - ACPI performance management activated.\n", cpu);
706         for (i = 0; i < perf->state_count; i++)
707                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
708                         (i == perf->state ? '*' : ' '), i,
709                         (u32) perf->states[i].core_frequency,
710                         (u32) perf->states[i].power,
711                         (u32) perf->states[i].transition_latency);
712
713         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
714
715         /*
716          * the first call to ->target() should result in us actually
717          * writing something to the appropriate registers.
718          */
719         data->resume = 1;
720
721         return result;
722
723 err_freqfree:
724         kfree(data->freq_table);
725 err_unreg:
726         acpi_processor_unregister_performance(perf, cpu);
727 err_free:
728         kfree(data);
729         per_cpu(drv_data, cpu) = NULL;
730
731         return result;
732 }
733
734 static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
735 {
736         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
737
738         dprintk("acpi_cpufreq_cpu_exit\n");
739
740         if (data) {
741                 cpufreq_frequency_table_put_attr(policy->cpu);
742                 per_cpu(drv_data, policy->cpu) = NULL;
743                 acpi_processor_unregister_performance(data->acpi_data,
744                                                       policy->cpu);
745                 kfree(data);
746         }
747
748         return 0;
749 }
750
751 static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
752 {
753         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
754
755         dprintk("acpi_cpufreq_resume\n");
756
757         data->resume = 1;
758
759         return 0;
760 }
761
762 static struct freq_attr *acpi_cpufreq_attr[] = {
763         &cpufreq_freq_attr_scaling_available_freqs,
764         NULL,
765 };
766
767 static struct cpufreq_driver acpi_cpufreq_driver = {
768         .verify = acpi_cpufreq_verify,
769         .target = acpi_cpufreq_target,
770         .init = acpi_cpufreq_cpu_init,
771         .exit = acpi_cpufreq_cpu_exit,
772         .resume = acpi_cpufreq_resume,
773         .name = "acpi-cpufreq",
774         .owner = THIS_MODULE,
775         .attr = acpi_cpufreq_attr,
776 };
777
778 static int __init acpi_cpufreq_init(void)
779 {
780         int ret;
781
782         dprintk("acpi_cpufreq_init\n");
783
784         ret = acpi_cpufreq_early_init();
785         if (ret)
786                 return ret;
787
788         return cpufreq_register_driver(&acpi_cpufreq_driver);
789 }
790
791 static void __exit acpi_cpufreq_exit(void)
792 {
793         dprintk("acpi_cpufreq_exit\n");
794
795         cpufreq_unregister_driver(&acpi_cpufreq_driver);
796
797         free_percpu(acpi_perf_data);
798
799         return;
800 }
801
802 module_param(acpi_pstate_strict, uint, 0644);
803 MODULE_PARM_DESC(acpi_pstate_strict,
804         "value 0 or non-zero. non-zero -> strict ACPI checks are "
805         "performed during frequency changes.");
806
807 late_initcall(acpi_cpufreq_init);
808 module_exit(acpi_cpufreq_exit);
809
810 MODULE_ALIAS("acpi");