Merge git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6
[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 #include <linux/ftrace.h>
37
38 #include <linux/acpi.h>
39 #include <acpi/processor.h>
40
41 #include <asm/io.h>
42 #include <asm/msr.h>
43 #include <asm/processor.h>
44 #include <asm/cpufeature.h>
45 #include <asm/delay.h>
46 #include <asm/uaccess.h>
47
48 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
49
50 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
51 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
52 MODULE_LICENSE("GPL");
53
54 enum {
55         UNDEFINED_CAPABLE = 0,
56         SYSTEM_INTEL_MSR_CAPABLE,
57         SYSTEM_IO_CAPABLE,
58 };
59
60 #define INTEL_MSR_RANGE         (0xffff)
61 #define CPUID_6_ECX_APERFMPERF_CAPABILITY       (0x1)
62
63 struct acpi_cpufreq_data {
64         struct acpi_processor_performance *acpi_data;
65         struct cpufreq_frequency_table *freq_table;
66         unsigned int max_freq;
67         unsigned int resume;
68         unsigned int cpu_feature;
69 };
70
71 static DEFINE_PER_CPU(struct acpi_cpufreq_data *, drv_data);
72
73 /* acpi_perf_data is a pointer to percpu data. */
74 static struct acpi_processor_performance *acpi_perf_data;
75
76 static struct cpufreq_driver acpi_cpufreq_driver;
77
78 static unsigned int acpi_pstate_strict;
79
80 static int check_est_cpu(unsigned int cpuid)
81 {
82         struct cpuinfo_x86 *cpu = &cpu_data(cpuid);
83
84         if (cpu->x86_vendor != X86_VENDOR_INTEL ||
85             !cpu_has(cpu, X86_FEATURE_EST))
86                 return 0;
87
88         return 1;
89 }
90
91 static unsigned extract_io(u32 value, struct acpi_cpufreq_data *data)
92 {
93         struct acpi_processor_performance *perf;
94         int i;
95
96         perf = data->acpi_data;
97
98         for (i=0; i<perf->state_count; i++) {
99                 if (value == perf->states[i].status)
100                         return data->freq_table[i].frequency;
101         }
102         return 0;
103 }
104
105 static unsigned extract_msr(u32 msr, struct acpi_cpufreq_data *data)
106 {
107         int i;
108         struct acpi_processor_performance *perf;
109
110         msr &= INTEL_MSR_RANGE;
111         perf = data->acpi_data;
112
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;
116         }
117         return data->freq_table[0].frequency;
118 }
119
120 static unsigned extract_freq(u32 val, struct acpi_cpufreq_data *data)
121 {
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);
127         default:
128                 return 0;
129         }
130 }
131
132 struct msr_addr {
133         u32 reg;
134 };
135
136 struct io_addr {
137         u16 port;
138         u8 bit_width;
139 };
140
141 typedef union {
142         struct msr_addr msr;
143         struct io_addr io;
144 } drv_addr_union;
145
146 struct drv_cmd {
147         unsigned int type;
148         cpumask_var_t mask;
149         drv_addr_union addr;
150         u32 val;
151 };
152
153 static void do_drv_read(struct drv_cmd *cmd)
154 {
155         u32 h;
156
157         switch (cmd->type) {
158         case SYSTEM_INTEL_MSR_CAPABLE:
159                 rdmsr(cmd->addr.msr.reg, cmd->val, h);
160                 break;
161         case SYSTEM_IO_CAPABLE:
162                 acpi_os_read_port((acpi_io_address)cmd->addr.io.port,
163                                 &cmd->val,
164                                 (u32)cmd->addr.io.bit_width);
165                 break;
166         default:
167                 break;
168         }
169 }
170
171 static void do_drv_write(struct drv_cmd *cmd)
172 {
173         u32 lo, hi;
174
175         switch (cmd->type) {
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);
180                 break;
181         case SYSTEM_IO_CAPABLE:
182                 acpi_os_write_port((acpi_io_address)cmd->addr.io.port,
183                                 cmd->val,
184                                 (u32)cmd->addr.io.bit_width);
185                 break;
186         default:
187                 break;
188         }
189 }
190
191 static void drv_read(struct drv_cmd *cmd)
192 {
193         cpumask_t saved_mask = current->cpus_allowed;
194         cmd->val = 0;
195
196         set_cpus_allowed_ptr(current, cmd->mask);
197         do_drv_read(cmd);
198         set_cpus_allowed_ptr(current, &saved_mask);
199 }
200
201 static void drv_write(struct drv_cmd *cmd)
202 {
203         cpumask_t saved_mask = current->cpus_allowed;
204         unsigned int i;
205
206         for_each_cpu(i, cmd->mask) {
207                 set_cpus_allowed_ptr(current, cpumask_of(i));
208                 do_drv_write(cmd);
209         }
210
211         set_cpus_allowed_ptr(current, &saved_mask);
212         return;
213 }
214
215 static u32 get_cur_val(const struct cpumask *mask)
216 {
217         struct acpi_processor_performance *perf;
218         struct drv_cmd cmd;
219
220         if (unlikely(cpumask_empty(mask)))
221                 return 0;
222
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;
227                 break;
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;
233                 break;
234         default:
235                 return 0;
236         }
237
238         cpumask_copy(cmd.mask, mask);
239
240         drv_read(&cmd);
241
242         dprintk("get_cur_val = %u\n", cmd.val);
243
244         return cmd.val;
245 }
246
247 struct perf_cur {
248         union {
249                 struct {
250                         u32 lo;
251                         u32 hi;
252                 } split;
253                 u64 whole;
254         } aperf_cur, mperf_cur;
255 };
256
257
258 static long read_measured_perf_ctrs(void *_cur)
259 {
260         struct perf_cur *cur = _cur;
261
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);
264
265         wrmsr(MSR_IA32_APERF, 0, 0);
266         wrmsr(MSR_IA32_MPERF, 0, 0);
267
268         return 0;
269 }
270
271 /*
272  * Return the measured active (C0) frequency on this CPU since last call
273  * to this function.
274  * Input: cpu number
275  * Return: Average CPU frequency in terms of max frequency (zero on error)
276  *
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.
283  */
284 static unsigned int get_measured_perf(struct cpufreq_policy *policy,
285                                       unsigned int cpu)
286 {
287         struct perf_cur cur;
288         unsigned int perf_percent;
289         unsigned int retval;
290
291         if (!work_on_cpu(cpu, read_measured_perf_ctrs, &cur))
292                 return 0;
293
294 #ifdef __i386__
295         /*
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.
299          */
300         if (unlikely(cur.aperf_cur.split.hi || cur.mperf_cur.split.hi)) {
301                 int shift_count;
302                 u32 h;
303
304                 h = max_t(u32, cur.aperf_cur.split.hi, cur.mperf_cur.split.hi);
305                 shift_count = fls(h);
306
307                 cur.aperf_cur.whole >>= shift_count;
308                 cur.mperf_cur.whole >>= shift_count;
309         }
310
311         if (((unsigned long)(-1) / 100) < cur.aperf_cur.split.lo) {
312                 int shift_count = 7;
313                 cur.aperf_cur.split.lo >>= shift_count;
314                 cur.mperf_cur.split.lo >>= shift_count;
315         }
316
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;
320         else
321                 perf_percent = 0;
322
323 #else
324         if (unlikely(((unsigned long)(-1) / 100) < cur.aperf_cur.whole)) {
325                 int shift_count = 7;
326                 cur.aperf_cur.whole >>= shift_count;
327                 cur.mperf_cur.whole >>= shift_count;
328         }
329
330         if (cur.aperf_cur.whole && cur.mperf_cur.whole)
331                 perf_percent = (cur.aperf_cur.whole * 100) /
332                                 cur.mperf_cur.whole;
333         else
334                 perf_percent = 0;
335
336 #endif
337
338         retval = per_cpu(drv_data, policy->cpu)->max_freq * perf_percent / 100;
339
340         return retval;
341 }
342
343 static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
344 {
345         struct acpi_cpufreq_data *data = per_cpu(drv_data, cpu);
346         unsigned int freq;
347         unsigned int cached_freq;
348
349         dprintk("get_cur_freq_on_cpu (%d)\n", cpu);
350
351         if (unlikely(data == NULL ||
352                      data->acpi_data == NULL || data->freq_table == NULL)) {
353                 return 0;
354         }
355
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) {
359                 /*
360                  * The dreaded BIOS frequency change behind our back.
361                  * Force set the frequency on next target call.
362                  */
363                 data->resume = 1;
364         }
365
366         dprintk("cur freq = %u\n", freq);
367
368         return freq;
369 }
370
371 static unsigned int check_freqs(const cpumask_t *mask, unsigned int freq,
372                                 struct acpi_cpufreq_data *data)
373 {
374         unsigned int cur_freq;
375         unsigned int i;
376
377         for (i=0; i<100; i++) {
378                 cur_freq = extract_freq(get_cur_val(mask), data);
379                 if (cur_freq == freq)
380                         return 1;
381                 udelay(10);
382         }
383         return 0;
384 }
385
386 static int acpi_cpufreq_target(struct cpufreq_policy *policy,
387                                unsigned int target_freq, unsigned int relation)
388 {
389         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
390         struct acpi_processor_performance *perf;
391         struct cpufreq_freqs freqs;
392         struct drv_cmd cmd;
393         unsigned int next_state = 0; /* Index into freq_table */
394         unsigned int next_perf_state = 0; /* Index into perf table */
395         unsigned int i;
396         int result = 0;
397         struct power_trace it;
398
399         dprintk("acpi_cpufreq_target %d (%d)\n", target_freq, policy->cpu);
400
401         if (unlikely(data == NULL ||
402              data->acpi_data == NULL || data->freq_table == NULL)) {
403                 return -ENODEV;
404         }
405
406         if (unlikely(!alloc_cpumask_var(&cmd.mask, GFP_KERNEL)))
407                 return -ENOMEM;
408
409         perf = data->acpi_data;
410         result = cpufreq_frequency_table_target(policy,
411                                                 data->freq_table,
412                                                 target_freq,
413                                                 relation, &next_state);
414         if (unlikely(result)) {
415                 result = -ENODEV;
416                 goto out;
417         }
418
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",
423                                 next_perf_state);
424                         data->resume = 0;
425                 } else {
426                         dprintk("Already at target state (P%d)\n",
427                                 next_perf_state);
428                         goto out;
429                 }
430         }
431
432         trace_power_mark(&it, POWER_PSTATE, next_perf_state);
433
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;
439                 break;
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;
445                 break;
446         default:
447                 result = -ENODEV;
448                 goto out;
449         }
450
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);
454         else
455                 cpumask_copy(cmd.mask, cpumask_of(policy->cpu));
456
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) {
460                 freqs.cpu = i;
461                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
462         }
463
464         drv_write(&cmd);
465
466         if (acpi_pstate_strict) {
467                 if (!check_freqs(cmd.mask, freqs.new, data)) {
468                         dprintk("acpi_cpufreq_target failed (%d)\n",
469                                 policy->cpu);
470                         result = -EAGAIN;
471                         goto out;
472                 }
473         }
474
475         for_each_cpu(i, cmd.mask) {
476                 freqs.cpu = i;
477                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
478         }
479         perf->state = next_perf_state;
480
481 out:
482         free_cpumask_var(cmd.mask);
483         return result;
484 }
485
486 static int acpi_cpufreq_verify(struct cpufreq_policy *policy)
487 {
488         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
489
490         dprintk("acpi_cpufreq_verify\n");
491
492         return cpufreq_frequency_table_verify(policy, data->freq_table);
493 }
494
495 static unsigned long
496 acpi_cpufreq_guess_freq(struct acpi_cpufreq_data *data, unsigned int cpu)
497 {
498         struct acpi_processor_performance *perf = data->acpi_data;
499
500         if (cpu_khz) {
501                 /* search the closest match to cpu_khz */
502                 unsigned int i;
503                 unsigned long freq;
504                 unsigned long freqn = perf->states[0].core_frequency * 1000;
505
506                 for (i=0; i<(perf->state_count-1); i++) {
507                         freq = freqn;
508                         freqn = perf->states[i+1].core_frequency * 1000;
509                         if ((2 * cpu_khz) > (freqn + freq)) {
510                                 perf->state = i;
511                                 return freq;
512                         }
513                 }
514                 perf->state = perf->state_count-1;
515                 return freqn;
516         } else {
517                 /* assume CPU is at P0... */
518                 perf->state = 0;
519                 return perf->states[0].core_frequency * 1000;
520         }
521 }
522
523 static void free_acpi_perf_data(void)
524 {
525         unsigned int i;
526
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)
530                                  ->shared_cpu_map);
531         free_percpu(acpi_perf_data);
532 }
533
534 /*
535  * acpi_cpufreq_early_init - initialize ACPI P-States library
536  *
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...
541  */
542 static int __init acpi_cpufreq_early_init(void)
543 {
544         unsigned int i;
545         dprintk("acpi_cpufreq_early_init\n");
546
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");
550                 return -ENOMEM;
551         }
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))) {
556
557                         /* Freeing a NULL pointer is OK: alloc_percpu zeroes. */
558                         free_acpi_perf_data();
559                         return -ENOMEM;
560                 }
561         }
562
563         /* Do initialization in ACPI core */
564         acpi_processor_preregister_performance(acpi_perf_data);
565         return 0;
566 }
567
568 #ifdef CONFIG_SMP
569 /*
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.
574  */
575 static int bios_with_sw_any_bug;
576
577 static int sw_any_bug_found(const struct dmi_system_id *d)
578 {
579         bios_with_sw_any_bug = 1;
580         return 0;
581 }
582
583 static const struct dmi_system_id sw_any_bug_dmi_table[] = {
584         {
585                 .callback = sw_any_bug_found,
586                 .ident = "Supermicro Server X6DLP",
587                 .matches = {
588                         DMI_MATCH(DMI_SYS_VENDOR, "Supermicro"),
589                         DMI_MATCH(DMI_BIOS_VERSION, "080010"),
590                         DMI_MATCH(DMI_PRODUCT_NAME, "X6DLP"),
591                 },
592         },
593         { }
594 };
595 #endif
596
597 static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
598 {
599         unsigned int i;
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;
606
607         dprintk("acpi_cpufreq_cpu_init\n");
608
609         data = kzalloc(sizeof(struct acpi_cpufreq_data), GFP_KERNEL);
610         if (!data)
611                 return -ENOMEM;
612
613         data->acpi_data = percpu_ptr(acpi_perf_data, cpu);
614         per_cpu(drv_data, cpu) = data;
615
616         if (cpu_has(c, X86_FEATURE_CONSTANT_TSC))
617                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
618
619         result = acpi_processor_register_performance(data->acpi_data, cpu);
620         if (result)
621                 goto err_free;
622
623         perf = data->acpi_data;
624         policy->shared_type = perf->shared_type;
625
626         /*
627          * Will let policy->cpus know about dependency only when software
628          * coordination is required.
629          */
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);
633         }
634         cpumask_copy(policy->related_cpus, perf->shared_cpu_map);
635
636 #ifdef CONFIG_SMP
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));
641         }
642 #endif
643
644         /* capability check */
645         if (perf->state_count <= 1) {
646                 dprintk("No P-States\n");
647                 result = -ENODEV;
648                 goto err_unreg;
649         }
650
651         if (perf->control_register.space_id != perf->status_register.space_id) {
652                 result = -ENODEV;
653                 goto err_unreg;
654         }
655
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;
660                 break;
661         case ACPI_ADR_SPACE_FIXED_HARDWARE:
662                 dprintk("HARDWARE addr space\n");
663                 if (!check_est_cpu(cpu)) {
664                         result = -ENODEV;
665                         goto err_unreg;
666                 }
667                 data->cpu_feature = SYSTEM_INTEL_MSR_CAPABLE;
668                 break;
669         default:
670                 dprintk("Unknown addr space %d\n",
671                         (u32) (perf->control_register.space_id));
672                 result = -ENODEV;
673                 goto err_unreg;
674         }
675
676         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
677                     (perf->state_count+1), GFP_KERNEL);
678         if (!data->freq_table) {
679                 result = -ENOMEM;
680                 goto err_unreg;
681         }
682
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;
690         }
691
692         data->max_freq = perf->states[0].core_frequency * 1000;
693         /* table init */
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)
697                         continue;
698
699                 data->freq_table[valid_states].index = i;
700                 data->freq_table[valid_states].frequency =
701                     perf->states[i].core_frequency * 1000;
702                 valid_states++;
703         }
704         data->freq_table[valid_states].frequency = CPUFREQ_TABLE_END;
705         perf->state = 0;
706
707         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
708         if (result)
709                 goto err_freqfree;
710
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);
715                 break;
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);
719                 break;
720         default:
721                 break;
722         }
723
724         /* notify BIOS that we exist */
725         acpi_processor_notify_smm(THIS_MODULE);
726
727         /* Check for APERF/MPERF support in hardware */
728         if (c->x86_vendor == X86_VENDOR_INTEL && c->cpuid_level >= 6) {
729                 unsigned int ecx;
730                 ecx = cpuid_ecx(6);
731                 if (ecx & CPUID_6_ECX_APERFMPERF_CAPABILITY)
732                         acpi_cpufreq_driver.getavg = get_measured_perf;
733         }
734
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);
742
743         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
744
745         /*
746          * the first call to ->target() should result in us actually
747          * writing something to the appropriate registers.
748          */
749         data->resume = 1;
750
751         return result;
752
753 err_freqfree:
754         kfree(data->freq_table);
755 err_unreg:
756         acpi_processor_unregister_performance(perf, cpu);
757 err_free:
758         kfree(data);
759         per_cpu(drv_data, cpu) = NULL;
760
761         return result;
762 }
763
764 static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
765 {
766         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
767
768         dprintk("acpi_cpufreq_cpu_exit\n");
769
770         if (data) {
771                 cpufreq_frequency_table_put_attr(policy->cpu);
772                 per_cpu(drv_data, policy->cpu) = NULL;
773                 acpi_processor_unregister_performance(data->acpi_data,
774                                                       policy->cpu);
775                 kfree(data);
776         }
777
778         return 0;
779 }
780
781 static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
782 {
783         struct acpi_cpufreq_data *data = per_cpu(drv_data, policy->cpu);
784
785         dprintk("acpi_cpufreq_resume\n");
786
787         data->resume = 1;
788
789         return 0;
790 }
791
792 static struct freq_attr *acpi_cpufreq_attr[] = {
793         &cpufreq_freq_attr_scaling_available_freqs,
794         NULL,
795 };
796
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,
806 };
807
808 static int __init acpi_cpufreq_init(void)
809 {
810         int ret;
811
812         if (acpi_disabled)
813                 return 0;
814
815         dprintk("acpi_cpufreq_init\n");
816
817         ret = acpi_cpufreq_early_init();
818         if (ret)
819                 return ret;
820
821         ret = cpufreq_register_driver(&acpi_cpufreq_driver);
822         if (ret)
823                 free_acpi_perf_data();
824
825         return ret;
826 }
827
828 static void __exit acpi_cpufreq_exit(void)
829 {
830         dprintk("acpi_cpufreq_exit\n");
831
832         cpufreq_unregister_driver(&acpi_cpufreq_driver);
833
834         free_percpu(acpi_perf_data);
835 }
836
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.");
841
842 late_initcall(acpi_cpufreq_init);
843 module_exit(acpi_cpufreq_exit);
844
845 MODULE_ALIAS("acpi");