Merge branch 'linus' into release
[linux-3.10.git] / arch / x86 / kernel / cpu / cpufreq / acpi-cpufreq.c
1 /*
2  * acpi-cpufreq.c - ACPI Processor P-States Driver
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 #include <linux/ftrace.h>
37
38 #include <linux/acpi.h>
39 #include <linux/io.h>
40 #include <linux/delay.h>
41 #include <linux/uaccess.h>
42
43 #include <acpi/processor.h>
44
45 #include <asm/msr.h>
46 #include <asm/processor.h>
47 #include <asm/cpufeature.h>
48
49 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
50                 "acpi-cpufreq", msg)
51
52 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
53 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
54 MODULE_LICENSE("GPL");
55
56 enum {
57         UNDEFINED_CAPABLE = 0,
58         SYSTEM_INTEL_MSR_CAPABLE,
59         SYSTEM_IO_CAPABLE,
60 };
61
62 #define INTEL_MSR_RANGE         (0xffff)
63 #define CPUID_6_ECX_APERFMPERF_CAPABILITY       (0x1)
64
65 struct acpi_cpufreq_data {
66         struct acpi_processor_performance *acpi_data;
67         struct cpufreq_frequency_table *freq_table;
68         unsigned int max_freq;
69         unsigned int resume;
70         unsigned int cpu_feature;
71 };
72
73 static DEFINE_PER_CPU(struct acpi_cpufreq_data *, drv_data);
74
75 /* acpi_perf_data is a pointer to percpu data. */
76 static struct acpi_processor_performance *acpi_perf_data;
77
78 static struct cpufreq_driver acpi_cpufreq_driver;
79
80 static unsigned int acpi_pstate_strict;
81
82 static int check_est_cpu(unsigned int cpuid)
83 {
84         struct cpuinfo_x86 *cpu = &cpu_data(cpuid);
85
86         if (cpu->x86_vendor != X86_VENDOR_INTEL ||
87             !cpu_has(cpu, X86_FEATURE_EST))
88                 return 0;
89
90         return 1;
91 }
92
93 static unsigned extract_io(u32 value, struct acpi_cpufreq_data *data)
94 {
95         struct acpi_processor_performance *perf;
96         int i;
97
98         perf = data->acpi_data;
99
100         for (i = 0; i < perf->state_count; i++) {
101                 if (value == perf->states[i].status)
102                         return data->freq_table[i].frequency;
103         }
104         return 0;
105 }
106
107 static unsigned extract_msr(u32 msr, struct acpi_cpufreq_data *data)
108 {
109         int i;
110         struct acpi_processor_performance *perf;
111
112         msr &= INTEL_MSR_RANGE;
113         perf = data->acpi_data;
114
115         for (i = 0; data->freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
116                 if (msr == perf->states[data->freq_table[i].index].status)
117                         return data->freq_table[i].frequency;
118         }
119         return data->freq_table[0].frequency;
120 }
121
122 static unsigned extract_freq(u32 val, struct acpi_cpufreq_data *data)
123 {
124         switch (data->cpu_feature) {
125         case SYSTEM_INTEL_MSR_CAPABLE:
126                 return extract_msr(val, data);
127         case SYSTEM_IO_CAPABLE:
128                 return extract_io(val, data);
129         default:
130                 return 0;
131         }
132 }
133
134 struct msr_addr {
135         u32 reg;
136 };
137
138 struct io_addr {
139         u16 port;
140         u8 bit_width;
141 };
142
143 struct drv_cmd {
144         unsigned int type;
145         const struct cpumask *mask;
146         union {
147                 struct msr_addr msr;
148                 struct io_addr io;
149         } addr;
150         u32 val;
151 };
152
153 static long do_drv_read(void *_cmd)
154 {
155         struct drv_cmd *cmd = _cmd;
156         u32 h;
157
158         switch (cmd->type) {
159         case SYSTEM_INTEL_MSR_CAPABLE:
160                 rdmsr(cmd->addr.msr.reg, cmd->val, h);
161                 break;
162         case SYSTEM_IO_CAPABLE:
163                 acpi_os_read_port((acpi_io_address)cmd->addr.io.port,
164                                 &cmd->val,
165                                 (u32)cmd->addr.io.bit_width);
166                 break;
167         default:
168                 break;
169         }
170         return 0;
171 }
172
173 static long do_drv_write(void *_cmd)
174 {
175         struct drv_cmd *cmd = _cmd;
176         u32 lo, hi;
177
178         switch (cmd->type) {
179         case SYSTEM_INTEL_MSR_CAPABLE:
180                 rdmsr(cmd->addr.msr.reg, lo, hi);
181                 lo = (lo & ~INTEL_MSR_RANGE) | (cmd->val & INTEL_MSR_RANGE);
182                 wrmsr(cmd->addr.msr.reg, lo, hi);
183                 break;
184         case SYSTEM_IO_CAPABLE:
185                 acpi_os_write_port((acpi_io_address)cmd->addr.io.port,
186                                 cmd->val,
187                                 (u32)cmd->addr.io.bit_width);
188                 break;
189         default:
190                 break;
191         }
192         return 0;
193 }
194
195 static void drv_read(struct drv_cmd *cmd)
196 {
197         cmd->val = 0;
198
199         work_on_cpu(cpumask_any(cmd->mask), do_drv_read, cmd);
200 }
201
202 static void drv_write(struct drv_cmd *cmd)
203 {
204         unsigned int i;
205
206         for_each_cpu(i, cmd->mask) {
207                 work_on_cpu(i, do_drv_write, cmd);
208         }
209 }
210
211 static u32 get_cur_val(const struct cpumask *mask)
212 {
213         struct acpi_processor_performance *perf;
214         struct drv_cmd cmd;
215
216         if (unlikely(cpumask_empty(mask)))
217                 return 0;
218
219         switch (per_cpu(drv_data, cpumask_first(mask))->cpu_feature) {
220         case SYSTEM_INTEL_MSR_CAPABLE:
221                 cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
222                 cmd.addr.msr.reg = MSR_IA32_PERF_STATUS;
223                 break;
224         case SYSTEM_IO_CAPABLE:
225                 cmd.type = SYSTEM_IO_CAPABLE;
226                 perf = per_cpu(drv_data, cpumask_first(mask))->acpi_data;
227                 cmd.addr.io.port = perf->control_register.address;
228                 cmd.addr.io.bit_width = perf->control_register.bit_width;
229                 break;
230         default:
231                 return 0;
232         }
233
234         cmd.mask = mask;
235         drv_read(&cmd);
236
237         dprintk("get_cur_val = %u\n", cmd.val);
238
239         return cmd.val;
240 }
241
242 struct perf_cur {
243         union {
244                 struct {
245                         u32 lo;
246                         u32 hi;
247                 } split;
248                 u64 whole;
249         } aperf_cur, mperf_cur;
250 };
251
252
253 static long read_measured_perf_ctrs(void *_cur)
254 {
255         struct perf_cur *cur = _cur;
256
257         rdmsr(MSR_IA32_APERF, cur->aperf_cur.split.lo, cur->aperf_cur.split.hi);
258         rdmsr(MSR_IA32_MPERF, cur->mperf_cur.split.lo, cur->mperf_cur.split.hi);
259
260         wrmsr(MSR_IA32_APERF, 0, 0);
261         wrmsr(MSR_IA32_MPERF, 0, 0);
262
263         return 0;
264 }
265
266 /*
267  * Return the measured active (C0) frequency on this CPU since last call
268  * to this function.
269  * Input: cpu number
270  * Return: Average CPU frequency in terms of max frequency (zero on error)
271  *
272  * We use IA32_MPERF and IA32_APERF MSRs to get the measured performance
273  * over a period of time, while CPU is in C0 state.
274  * IA32_MPERF counts at the rate of max advertised frequency
275  * IA32_APERF counts at the rate of actual CPU frequency
276  * Only IA32_APERF/IA32_MPERF ratio is architecturally defined and
277  * no meaning should be associated with absolute values of these MSRs.
278  */
279 static unsigned int get_measured_perf(struct cpufreq_policy *policy,
280                                       unsigned int cpu)
281 {
282         struct perf_cur cur;
283         unsigned int perf_percent;
284         unsigned int retval;
285
286         if (!work_on_cpu(cpu, read_measured_perf_ctrs, &cur))
287                 return 0;
288
289 #ifdef __i386__
290         /*
291          * We dont want to do 64 bit divide with 32 bit kernel
292          * Get an approximate value. Return failure in case we cannot get
293          * an approximate value.
294          */
295         if (unlikely(cur.aperf_cur.split.hi || cur.mperf_cur.split.hi)) {
296                 int shift_count;
297                 u32 h;
298
299                 h = max_t(u32, cur.aperf_cur.split.hi, cur.mperf_cur.split.hi);
300                 shift_count = fls(h);
301
302                 cur.aperf_cur.whole >>= shift_count;
303                 cur.mperf_cur.whole >>= shift_count;
304         }
305
306         if (((unsigned long)(-1) / 100) < cur.aperf_cur.split.lo) {
307                 int shift_count = 7;
308                 cur.aperf_cur.split.lo >>= shift_count;
309                 cur.mperf_cur.split.lo >>= shift_count;
310         }
311
312         if (cur.aperf_cur.split.lo && cur.mperf_cur.split.lo)
313                 perf_percent = (cur.aperf_cur.split.lo * 100) /
314                                 cur.mperf_cur.split.lo;
315         else
316                 perf_percent = 0;
317
318 #else
319         if (unlikely(((unsigned long)(-1) / 100) < cur.aperf_cur.whole)) {
320                 int shift_count = 7;
321                 cur.aperf_cur.whole >>= shift_count;
322                 cur.mperf_cur.whole >>= shift_count;
323         }
324
325         if (cur.aperf_cur.whole && cur.mperf_cur.whole)
326                 perf_percent = (cur.aperf_cur.whole * 100) /
327                                 cur.mperf_cur.whole;
328         else
329                 perf_percent = 0;
330
331 #endif
332
333         retval = per_cpu(drv_data, policy->cpu)->max_freq * perf_percent / 100;
334
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)), 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 struct cpumask *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         struct drv_cmd cmd;
388         unsigned int next_state = 0; /* Index into freq_table */
389         unsigned int next_perf_state = 0; /* Index into perf table */
390         unsigned int i;
391         int result = 0;
392         struct power_trace it;
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                 result = -ENODEV;
408                 goto out;
409         }
410
411         next_perf_state = data->freq_table[next_state].index;
412         if (perf->state == next_perf_state) {
413                 if (unlikely(data->resume)) {
414                         dprintk("Called after resume, resetting to P%d\n",
415                                 next_perf_state);
416                         data->resume = 0;
417                 } else {
418                         dprintk("Already at target state (P%d)\n",
419                                 next_perf_state);
420                         goto out;
421                 }
422         }
423
424         trace_power_mark(&it, POWER_PSTATE, next_perf_state);
425
426         switch (data->cpu_feature) {
427         case SYSTEM_INTEL_MSR_CAPABLE:
428                 cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
429                 cmd.addr.msr.reg = MSR_IA32_PERF_CTL;
430                 cmd.val = (u32) perf->states[next_perf_state].control;
431                 break;
432         case SYSTEM_IO_CAPABLE:
433                 cmd.type = SYSTEM_IO_CAPABLE;
434                 cmd.addr.io.port = perf->control_register.address;
435                 cmd.addr.io.bit_width = perf->control_register.bit_width;
436                 cmd.val = (u32) perf->states[next_perf_state].control;
437                 break;
438         default:
439                 result = -ENODEV;
440                 goto out;
441         }
442
443         /* cpufreq holds the hotplug lock, so we are safe from here on */
444         if (policy->shared_type != CPUFREQ_SHARED_TYPE_ANY)
445                 cmd.mask = policy->cpus;
446         else
447                 cmd.mask = cpumask_of(policy->cpu);
448
449         freqs.old = perf->states[perf->state].core_frequency * 1000;
450         freqs.new = data->freq_table[next_state].frequency;
451         for_each_cpu(i, cmd.mask) {
452                 freqs.cpu = i;
453                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
454         }
455
456         drv_write(&cmd);
457
458         if (acpi_pstate_strict) {
459                 if (!check_freqs(cmd.mask, freqs.new, data)) {
460                         dprintk("acpi_cpufreq_target failed (%d)\n",
461                                 policy->cpu);
462                         result = -EAGAIN;
463                         goto out;
464                 }
465         }
466
467         for_each_cpu(i, cmd.mask) {
468                 freqs.cpu = i;
469                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
470         }
471         perf->state = next_perf_state;
472
473 out:
474         return result;
475 }
476
477 static int acpi_cpufreq_verify(struct cpufreq_policy *policy)
478 {
479         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
480
481         dprintk("acpi_cpufreq_verify\n");
482
483         return cpufreq_frequency_table_verify(policy, data->freq_table);
484 }
485
486 static unsigned long
487 acpi_cpufreq_guess_freq(struct acpi_cpufreq_data *data, unsigned int cpu)
488 {
489         struct acpi_processor_performance *perf = data->acpi_data;
490
491         if (cpu_khz) {
492                 /* search the closest match to cpu_khz */
493                 unsigned int i;
494                 unsigned long freq;
495                 unsigned long freqn = perf->states[0].core_frequency * 1000;
496
497                 for (i = 0; i < (perf->state_count-1); i++) {
498                         freq = freqn;
499                         freqn = perf->states[i+1].core_frequency * 1000;
500                         if ((2 * cpu_khz) > (freqn + freq)) {
501                                 perf->state = i;
502                                 return freq;
503                         }
504                 }
505                 perf->state = perf->state_count-1;
506                 return freqn;
507         } else {
508                 /* assume CPU is at P0... */
509                 perf->state = 0;
510                 return perf->states[0].core_frequency * 1000;
511         }
512 }
513
514 static void free_acpi_perf_data(void)
515 {
516         unsigned int i;
517
518         /* Freeing a NULL pointer is OK, and alloc_percpu zeroes. */
519         for_each_possible_cpu(i)
520                 free_cpumask_var(per_cpu_ptr(acpi_perf_data, i)
521                                  ->shared_cpu_map);
522         free_percpu(acpi_perf_data);
523 }
524
525 /*
526  * acpi_cpufreq_early_init - initialize ACPI P-States library
527  *
528  * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
529  * in order to determine correct frequency and voltage pairings. We can
530  * do _PDC and _PSD and find out the processor dependency for the
531  * actual init that will happen later...
532  */
533 static int __init acpi_cpufreq_early_init(void)
534 {
535         unsigned int i;
536         dprintk("acpi_cpufreq_early_init\n");
537
538         acpi_perf_data = alloc_percpu(struct acpi_processor_performance);
539         if (!acpi_perf_data) {
540                 dprintk("Memory allocation error for acpi_perf_data.\n");
541                 return -ENOMEM;
542         }
543         for_each_possible_cpu(i) {
544                 if (!alloc_cpumask_var_node(
545                         &per_cpu_ptr(acpi_perf_data, i)->shared_cpu_map,
546                         GFP_KERNEL, cpu_to_node(i))) {
547
548                         /* Freeing a NULL pointer is OK: alloc_percpu zeroes. */
549                         free_acpi_perf_data();
550                         return -ENOMEM;
551                 }
552         }
553
554         /* Do initialization in ACPI core */
555         acpi_processor_preregister_performance(acpi_perf_data);
556         return 0;
557 }
558
559 #ifdef CONFIG_SMP
560 /*
561  * Some BIOSes do SW_ANY coordination internally, either set it up in hw
562  * or do it in BIOS firmware and won't inform about it to OS. If not
563  * detected, this has a side effect of making CPU run at a different speed
564  * than OS intended it to run at. Detect it and handle it cleanly.
565  */
566 static int bios_with_sw_any_bug;
567
568 static int sw_any_bug_found(const struct dmi_system_id *d)
569 {
570         bios_with_sw_any_bug = 1;
571         return 0;
572 }
573
574 static const struct dmi_system_id sw_any_bug_dmi_table[] = {
575         {
576                 .callback = sw_any_bug_found,
577                 .ident = "Supermicro Server X6DLP",
578                 .matches = {
579                         DMI_MATCH(DMI_SYS_VENDOR, "Supermicro"),
580                         DMI_MATCH(DMI_BIOS_VERSION, "080010"),
581                         DMI_MATCH(DMI_PRODUCT_NAME, "X6DLP"),
582                 },
583         },
584         { }
585 };
586 #endif
587
588 static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
589 {
590         unsigned int i;
591         unsigned int valid_states = 0;
592         unsigned int cpu = policy->cpu;
593         struct acpi_cpufreq_data *data;
594         unsigned int result = 0;
595         struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
596         struct acpi_processor_performance *perf;
597
598         dprintk("acpi_cpufreq_cpu_init\n");
599
600         data = kzalloc(sizeof(struct acpi_cpufreq_data), GFP_KERNEL);
601         if (!data)
602                 return -ENOMEM;
603
604         data->acpi_data = per_cpu_ptr(acpi_perf_data, cpu);
605         per_cpu(drv_data, cpu) = data;
606
607         if (cpu_has(c, X86_FEATURE_CONSTANT_TSC))
608                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
609
610         result = acpi_processor_register_performance(data->acpi_data, cpu);
611         if (result)
612                 goto err_free;
613
614         perf = data->acpi_data;
615         policy->shared_type = perf->shared_type;
616
617         /*
618          * Will let policy->cpus know about dependency only when software
619          * coordination is required.
620          */
621         if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
622             policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
623                 cpumask_copy(policy->cpus, perf->shared_cpu_map);
624         }
625         cpumask_copy(policy->related_cpus, perf->shared_cpu_map);
626
627 #ifdef CONFIG_SMP
628         dmi_check_system(sw_any_bug_dmi_table);
629         if (bios_with_sw_any_bug && cpumask_weight(policy->cpus) == 1) {
630                 policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
631                 cpumask_copy(policy->cpus, cpu_core_mask(cpu));
632         }
633 #endif
634
635         /* capability check */
636         if (perf->state_count <= 1) {
637                 dprintk("No P-States\n");
638                 result = -ENODEV;
639                 goto err_unreg;
640         }
641
642         if (perf->control_register.space_id != perf->status_register.space_id) {
643                 result = -ENODEV;
644                 goto err_unreg;
645         }
646
647         switch (perf->control_register.space_id) {
648         case ACPI_ADR_SPACE_SYSTEM_IO:
649                 dprintk("SYSTEM IO addr space\n");
650                 data->cpu_feature = SYSTEM_IO_CAPABLE;
651                 break;
652         case ACPI_ADR_SPACE_FIXED_HARDWARE:
653                 dprintk("HARDWARE addr space\n");
654                 if (!check_est_cpu(cpu)) {
655                         result = -ENODEV;
656                         goto err_unreg;
657                 }
658                 data->cpu_feature = SYSTEM_INTEL_MSR_CAPABLE;
659                 break;
660         default:
661                 dprintk("Unknown addr space %d\n",
662                         (u32) (perf->control_register.space_id));
663                 result = -ENODEV;
664                 goto err_unreg;
665         }
666
667         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
668                     (perf->state_count+1), GFP_KERNEL);
669         if (!data->freq_table) {
670                 result = -ENOMEM;
671                 goto err_unreg;
672         }
673
674         /* detect transition latency */
675         policy->cpuinfo.transition_latency = 0;
676         for (i = 0; i < perf->state_count; i++) {
677                 if ((perf->states[i].transition_latency * 1000) >
678                     policy->cpuinfo.transition_latency)
679                         policy->cpuinfo.transition_latency =
680                             perf->states[i].transition_latency * 1000;
681         }
682
683         /* Check for high latency (>20uS) from buggy BIOSes, like on T42 */
684         if (perf->control_register.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE &&
685             policy->cpuinfo.transition_latency > 20 * 1000) {
686                 static int print_once;
687                 policy->cpuinfo.transition_latency = 20 * 1000;
688                 if (!print_once) {
689                         print_once = 1;
690                         printk(KERN_INFO "Capping off P-state tranision latency"
691                                 " at 20 uS\n");
692                 }
693         }
694
695         data->max_freq = perf->states[0].core_frequency * 1000;
696         /* table init */
697         for (i = 0; i < perf->state_count; i++) {
698                 if (i > 0 && perf->states[i].core_frequency >=
699                     data->freq_table[valid_states-1].frequency / 1000)
700                         continue;
701
702                 data->freq_table[valid_states].index = i;
703                 data->freq_table[valid_states].frequency =
704                     perf->states[i].core_frequency * 1000;
705                 valid_states++;
706         }
707         data->freq_table[valid_states].frequency = CPUFREQ_TABLE_END;
708         perf->state = 0;
709
710         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
711         if (result)
712                 goto err_freqfree;
713
714         switch (perf->control_register.space_id) {
715         case ACPI_ADR_SPACE_SYSTEM_IO:
716                 /* Current speed is unknown and not detectable by IO port */
717                 policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
718                 break;
719         case ACPI_ADR_SPACE_FIXED_HARDWARE:
720                 acpi_cpufreq_driver.get = get_cur_freq_on_cpu;
721                 policy->cur = get_cur_freq_on_cpu(cpu);
722                 break;
723         default:
724                 break;
725         }
726
727         /* notify BIOS that we exist */
728         acpi_processor_notify_smm(THIS_MODULE);
729
730         /* Check for APERF/MPERF support in hardware */
731         if (c->x86_vendor == X86_VENDOR_INTEL && c->cpuid_level >= 6) {
732                 unsigned int ecx;
733                 ecx = cpuid_ecx(6);
734                 if (ecx & CPUID_6_ECX_APERFMPERF_CAPABILITY)
735                         acpi_cpufreq_driver.getavg = get_measured_perf;
736         }
737
738         dprintk("CPU%u - ACPI performance management activated.\n", cpu);
739         for (i = 0; i < perf->state_count; i++)
740                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
741                         (i == perf->state ? '*' : ' '), i,
742                         (u32) perf->states[i].core_frequency,
743                         (u32) perf->states[i].power,
744                         (u32) perf->states[i].transition_latency);
745
746         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
747
748         /*
749          * the first call to ->target() should result in us actually
750          * writing something to the appropriate registers.
751          */
752         data->resume = 1;
753
754         return result;
755
756 err_freqfree:
757         kfree(data->freq_table);
758 err_unreg:
759         acpi_processor_unregister_performance(perf, cpu);
760 err_free:
761         kfree(data);
762         per_cpu(drv_data, cpu) = NULL;
763
764         return result;
765 }
766
767 static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
768 {
769         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
770
771         dprintk("acpi_cpufreq_cpu_exit\n");
772
773         if (data) {
774                 cpufreq_frequency_table_put_attr(policy->cpu);
775                 per_cpu(drv_data, policy->cpu) = NULL;
776                 acpi_processor_unregister_performance(data->acpi_data,
777                                                       policy->cpu);
778                 kfree(data);
779         }
780
781         return 0;
782 }
783
784 static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
785 {
786         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
787
788         dprintk("acpi_cpufreq_resume\n");
789
790         data->resume = 1;
791
792         return 0;
793 }
794
795 static struct freq_attr *acpi_cpufreq_attr[] = {
796         &cpufreq_freq_attr_scaling_available_freqs,
797         NULL,
798 };
799
800 static struct cpufreq_driver acpi_cpufreq_driver = {
801         .verify = acpi_cpufreq_verify,
802         .target = acpi_cpufreq_target,
803         .init = acpi_cpufreq_cpu_init,
804         .exit = acpi_cpufreq_cpu_exit,
805         .resume = acpi_cpufreq_resume,
806         .name = "acpi-cpufreq",
807         .owner = THIS_MODULE,
808         .attr = acpi_cpufreq_attr,
809 };
810
811 static int __init acpi_cpufreq_init(void)
812 {
813         int ret;
814
815         if (acpi_disabled)
816                 return 0;
817
818         dprintk("acpi_cpufreq_init\n");
819
820         ret = acpi_cpufreq_early_init();
821         if (ret)
822                 return ret;
823
824         ret = cpufreq_register_driver(&acpi_cpufreq_driver);
825         if (ret)
826                 free_acpi_perf_data();
827
828         return ret;
829 }
830
831 static void __exit acpi_cpufreq_exit(void)
832 {
833         dprintk("acpi_cpufreq_exit\n");
834
835         cpufreq_unregister_driver(&acpi_cpufreq_driver);
836
837         free_percpu(acpi_perf_data);
838 }
839
840 module_param(acpi_pstate_strict, uint, 0644);
841 MODULE_PARM_DESC(acpi_pstate_strict,
842         "value 0 or non-zero. non-zero -> strict ACPI checks are "
843         "performed during frequency changes.");
844
845 late_initcall(acpi_cpufreq_init);
846 module_exit(acpi_cpufreq_exit);
847
848 MODULE_ALIAS("acpi");