Merge master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq
[sfrench/cifs-2.6.git] / arch / i386 / kernel / cpu / cpufreq / acpi-cpufreq.c
1 /*
2  * acpi-cpufreq.c - ACPI Processor P-States Driver ($Revision: 1.3 $)
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  *
8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or (at
13  *  your option) any later version.
14  *
15  *  This program is distributed in the hope that it will be useful, but
16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  *  General Public License for more details.
19  *
20  *  You should have received a copy of the GNU General Public License along
21  *  with this program; if not, write to the Free Software Foundation, Inc.,
22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
23  *
24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
25  */
26
27 #include <linux/config.h>
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/init.h>
31 #include <linux/cpufreq.h>
32 #include <linux/proc_fs.h>
33 #include <linux/seq_file.h>
34 #include <linux/compiler.h>
35 #include <linux/sched.h>        /* current */
36 #include <asm/io.h>
37 #include <asm/delay.h>
38 #include <asm/uaccess.h>
39
40 #include <linux/acpi.h>
41 #include <acpi/processor.h>
42
43 #include "speedstep-est-common.h"
44
45 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
46
47 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
48 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
49 MODULE_LICENSE("GPL");
50
51
52 struct cpufreq_acpi_io {
53         struct acpi_processor_performance       acpi_data;
54         struct cpufreq_frequency_table          *freq_table;
55         unsigned int                            resume;
56 };
57
58 static struct cpufreq_acpi_io   *acpi_io_data[NR_CPUS];
59
60 static struct cpufreq_driver acpi_cpufreq_driver;
61
62 static unsigned int acpi_pstate_strict;
63
64 static int
65 acpi_processor_write_port(
66         u16     port,
67         u8      bit_width,
68         u32     value)
69 {
70         if (bit_width <= 8) {
71                 outb(value, port);
72         } else if (bit_width <= 16) {
73                 outw(value, port);
74         } else if (bit_width <= 32) {
75                 outl(value, port);
76         } else {
77                 return -ENODEV;
78         }
79         return 0;
80 }
81
82 static int
83 acpi_processor_read_port(
84         u16     port,
85         u8      bit_width,
86         u32     *ret)
87 {
88         *ret = 0;
89         if (bit_width <= 8) {
90                 *ret = inb(port);
91         } else if (bit_width <= 16) {
92                 *ret = inw(port);
93         } else if (bit_width <= 32) {
94                 *ret = inl(port);
95         } else {
96                 return -ENODEV;
97         }
98         return 0;
99 }
100
101 static int
102 acpi_processor_set_performance (
103         struct cpufreq_acpi_io  *data,
104         unsigned int            cpu,
105         int                     state)
106 {
107         u16                     port = 0;
108         u8                      bit_width = 0;
109         int                     ret = 0;
110         u32                     value = 0;
111         int                     i = 0;
112         struct cpufreq_freqs    cpufreq_freqs;
113         cpumask_t               saved_mask;
114         int                     retval;
115
116         dprintk("acpi_processor_set_performance\n");
117
118         /*
119          * TBD: Use something other than set_cpus_allowed.
120          * As set_cpus_allowed is a bit racy, 
121          * with any other set_cpus_allowed for this process.
122          */
123         saved_mask = current->cpus_allowed;
124         set_cpus_allowed(current, cpumask_of_cpu(cpu));
125         if (smp_processor_id() != cpu) {
126                 return (-EAGAIN);
127         }
128         
129         if (state == data->acpi_data.state) {
130                 if (unlikely(data->resume)) {
131                         dprintk("Called after resume, resetting to P%d\n", state);
132                         data->resume = 0;
133                 } else {
134                         dprintk("Already at target state (P%d)\n", state);
135                         retval = 0;
136                         goto migrate_end;
137                 }
138         }
139
140         dprintk("Transitioning from P%d to P%d\n",
141                 data->acpi_data.state, state);
142
143         /* cpufreq frequency struct */
144         cpufreq_freqs.cpu = cpu;
145         cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
146         cpufreq_freqs.new = data->freq_table[state].frequency;
147
148         /* notify cpufreq */
149         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
150
151         /*
152          * First we write the target state's 'control' value to the
153          * control_register.
154          */
155
156         port = data->acpi_data.control_register.address;
157         bit_width = data->acpi_data.control_register.bit_width;
158         value = (u32) data->acpi_data.states[state].control;
159
160         dprintk("Writing 0x%08x to port 0x%04x\n", value, port);
161
162         ret = acpi_processor_write_port(port, bit_width, value);
163         if (ret) {
164                 dprintk("Invalid port width 0x%04x\n", bit_width);
165                 retval = ret;
166                 goto migrate_end;
167         }
168
169         /*
170          * Assume the write went through when acpi_pstate_strict is not used.
171          * As read status_register is an expensive operation and there 
172          * are no specific error cases where an IO port write will fail.
173          */
174         if (acpi_pstate_strict) {
175                 /* Then we read the 'status_register' and compare the value 
176                  * with the target state's 'status' to make sure the 
177                  * transition was successful.
178                  * Note that we'll poll for up to 1ms (100 cycles of 10us) 
179                  * before giving up.
180                  */
181
182                 port = data->acpi_data.status_register.address;
183                 bit_width = data->acpi_data.status_register.bit_width;
184
185                 dprintk("Looking for 0x%08x from port 0x%04x\n",
186                         (u32) data->acpi_data.states[state].status, port);
187
188                 for (i=0; i<100; i++) {
189                         ret = acpi_processor_read_port(port, bit_width, &value);
190                         if (ret) {      
191                                 dprintk("Invalid port width 0x%04x\n", bit_width);
192                                 retval = ret;
193                                 goto migrate_end;
194                         }
195                         if (value == (u32) data->acpi_data.states[state].status)
196                                 break;
197                         udelay(10);
198                 }
199         } else {
200                 i = 0;
201                 value = (u32) data->acpi_data.states[state].status;
202         }
203
204         /* notify cpufreq */
205         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
206
207         if (unlikely(value != (u32) data->acpi_data.states[state].status)) {
208                 unsigned int tmp = cpufreq_freqs.new;
209                 cpufreq_freqs.new = cpufreq_freqs.old;
210                 cpufreq_freqs.old = tmp;
211                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
212                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
213                 printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
214                 retval = -ENODEV;
215                 goto migrate_end;
216         }
217
218         dprintk("Transition successful after %d microseconds\n", i * 10);
219
220         data->acpi_data.state = state;
221
222         retval = 0;
223 migrate_end:
224         set_cpus_allowed(current, saved_mask);
225         return (retval);
226 }
227
228
229 static int
230 acpi_cpufreq_target (
231         struct cpufreq_policy   *policy,
232         unsigned int target_freq,
233         unsigned int relation)
234 {
235         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
236         unsigned int next_state = 0;
237         unsigned int result = 0;
238
239         dprintk("acpi_cpufreq_setpolicy\n");
240
241         result = cpufreq_frequency_table_target(policy,
242                         data->freq_table,
243                         target_freq,
244                         relation,
245                         &next_state);
246         if (result)
247                 return (result);
248
249         result = acpi_processor_set_performance (data, policy->cpu, next_state);
250
251         return (result);
252 }
253
254
255 static int
256 acpi_cpufreq_verify (
257         struct cpufreq_policy   *policy)
258 {
259         unsigned int result = 0;
260         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
261
262         dprintk("acpi_cpufreq_verify\n");
263
264         result = cpufreq_frequency_table_verify(policy, 
265                         data->freq_table);
266
267         return (result);
268 }
269
270
271 static unsigned long
272 acpi_cpufreq_guess_freq (
273         struct cpufreq_acpi_io  *data,
274         unsigned int            cpu)
275 {
276         if (cpu_khz) {
277                 /* search the closest match to cpu_khz */
278                 unsigned int i;
279                 unsigned long freq;
280                 unsigned long freqn = data->acpi_data.states[0].core_frequency * 1000;
281
282                 for (i=0; i < (data->acpi_data.state_count - 1); i++) {
283                         freq = freqn;
284                         freqn = data->acpi_data.states[i+1].core_frequency * 1000;
285                         if ((2 * cpu_khz) > (freqn + freq)) {
286                                 data->acpi_data.state = i;
287                                 return (freq);
288                         }
289                 }
290                 data->acpi_data.state = data->acpi_data.state_count - 1;
291                 return (freqn);
292         } else
293                 /* assume CPU is at P0... */
294                 data->acpi_data.state = 0;
295                 return data->acpi_data.states[0].core_frequency * 1000;
296         
297 }
298
299
300 /* 
301  * acpi_processor_cpu_init_pdc_est - let BIOS know about the SMP capabilities
302  * of this driver
303  * @perf: processor-specific acpi_io_data struct
304  * @cpu: CPU being initialized
305  *
306  * To avoid issues with legacy OSes, some BIOSes require to be informed of
307  * the SMP capabilities of OS P-state driver. Here we set the bits in _PDC 
308  * accordingly, for Enhanced Speedstep. Actual call to _PDC is done in
309  * driver/acpi/processor.c
310  */
311 static void 
312 acpi_processor_cpu_init_pdc_est(
313                 struct acpi_processor_performance *perf, 
314                 unsigned int cpu,
315                 struct acpi_object_list *obj_list
316                 )
317 {
318         union acpi_object *obj;
319         u32 *buf;
320         struct cpuinfo_x86 *c = cpu_data + cpu;
321         dprintk("acpi_processor_cpu_init_pdc_est\n");
322
323         if (!cpu_has(c, X86_FEATURE_EST))
324                 return;
325
326         /* Initialize pdc. It will be used later. */
327         if (!obj_list)
328                 return;
329                 
330         if (!(obj_list->count && obj_list->pointer))
331                 return;
332
333         obj = obj_list->pointer;
334         if ((obj->buffer.length == 12) && obj->buffer.pointer) {
335                 buf = (u32 *)obj->buffer.pointer;
336                 buf[0] = ACPI_PDC_REVISION_ID;
337                 buf[1] = 1;
338                 buf[2] = ACPI_PDC_EST_CAPABILITY_SMP;
339                 perf->pdc = obj_list;
340         }
341         return;
342 }
343  
344
345 /* CPU specific PDC initialization */
346 static void 
347 acpi_processor_cpu_init_pdc(
348                 struct acpi_processor_performance *perf, 
349                 unsigned int cpu,
350                 struct acpi_object_list *obj_list
351                 )
352 {
353         struct cpuinfo_x86 *c = cpu_data + cpu;
354         dprintk("acpi_processor_cpu_init_pdc\n");
355         perf->pdc = NULL;
356         if (cpu_has(c, X86_FEATURE_EST))
357                 acpi_processor_cpu_init_pdc_est(perf, cpu, obj_list);
358         return;
359 }
360
361
362 static int
363 acpi_cpufreq_cpu_init (
364         struct cpufreq_policy   *policy)
365 {
366         unsigned int            i;
367         unsigned int            cpu = policy->cpu;
368         struct cpufreq_acpi_io  *data;
369         unsigned int            result = 0;
370
371         union acpi_object               arg0 = {ACPI_TYPE_BUFFER};
372         u32                             arg0_buf[3];
373         struct acpi_object_list         arg_list = {1, &arg0};
374
375         dprintk("acpi_cpufreq_cpu_init\n");
376         /* setup arg_list for _PDC settings */
377         arg0.buffer.length = 12;
378         arg0.buffer.pointer = (u8 *) arg0_buf;
379
380         data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
381         if (!data)
382                 return (-ENOMEM);
383
384         acpi_io_data[cpu] = data;
385
386         acpi_processor_cpu_init_pdc(&data->acpi_data, cpu, &arg_list);
387         result = acpi_processor_register_performance(&data->acpi_data, cpu);
388         data->acpi_data.pdc = NULL;
389
390         if (result)
391                 goto err_free;
392
393         if (is_const_loops_cpu(cpu)) {
394                 acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
395         }
396
397         /* capability check */
398         if (data->acpi_data.state_count <= 1) {
399                 dprintk("No P-States\n");
400                 result = -ENODEV;
401                 goto err_unreg;
402         }
403         if ((data->acpi_data.control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
404             (data->acpi_data.status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
405                 dprintk("Unsupported address space [%d, %d]\n",
406                         (u32) (data->acpi_data.control_register.space_id),
407                         (u32) (data->acpi_data.status_register.space_id));
408                 result = -ENODEV;
409                 goto err_unreg;
410         }
411
412         /* alloc freq_table */
413         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (data->acpi_data.state_count + 1), GFP_KERNEL);
414         if (!data->freq_table) {
415                 result = -ENOMEM;
416                 goto err_unreg;
417         }
418
419         /* detect transition latency */
420         policy->cpuinfo.transition_latency = 0;
421         for (i=0; i<data->acpi_data.state_count; i++) {
422                 if ((data->acpi_data.states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
423                         policy->cpuinfo.transition_latency = data->acpi_data.states[i].transition_latency * 1000;
424         }
425         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
426
427         /* The current speed is unknown and not detectable by ACPI...  */
428         policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
429
430         /* table init */
431         for (i=0; i<=data->acpi_data.state_count; i++)
432         {
433                 data->freq_table[i].index = i;
434                 if (i<data->acpi_data.state_count)
435                         data->freq_table[i].frequency = data->acpi_data.states[i].core_frequency * 1000;
436                 else
437                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
438         }
439
440         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
441         if (result) {
442                 goto err_freqfree;
443         }
444
445         /* notify BIOS that we exist */
446         acpi_processor_notify_smm(THIS_MODULE);
447
448         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management activated.\n",
449                cpu);
450         for (i = 0; i < data->acpi_data.state_count; i++)
451                 dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
452                         (i == data->acpi_data.state?'*':' '), i,
453                         (u32) data->acpi_data.states[i].core_frequency,
454                         (u32) data->acpi_data.states[i].power,
455                         (u32) data->acpi_data.states[i].transition_latency);
456
457         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
458         
459         /*
460          * the first call to ->target() should result in us actually
461          * writing something to the appropriate registers.
462          */
463         data->resume = 1;
464         
465         return (result);
466
467  err_freqfree:
468         kfree(data->freq_table);
469  err_unreg:
470         acpi_processor_unregister_performance(&data->acpi_data, cpu);
471  err_free:
472         kfree(data);
473         acpi_io_data[cpu] = NULL;
474
475         return (result);
476 }
477
478
479 static int
480 acpi_cpufreq_cpu_exit (
481         struct cpufreq_policy   *policy)
482 {
483         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
484
485
486         dprintk("acpi_cpufreq_cpu_exit\n");
487
488         if (data) {
489                 cpufreq_frequency_table_put_attr(policy->cpu);
490                 acpi_io_data[policy->cpu] = NULL;
491                 acpi_processor_unregister_performance(&data->acpi_data, policy->cpu);
492                 kfree(data);
493         }
494
495         return (0);
496 }
497
498 static int
499 acpi_cpufreq_resume (
500         struct cpufreq_policy   *policy)
501 {
502         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
503
504
505         dprintk("acpi_cpufreq_resume\n");
506
507         data->resume = 1;
508
509         return (0);
510 }
511
512
513 static struct freq_attr* acpi_cpufreq_attr[] = {
514         &cpufreq_freq_attr_scaling_available_freqs,
515         NULL,
516 };
517
518 static struct cpufreq_driver acpi_cpufreq_driver = {
519         .verify         = acpi_cpufreq_verify,
520         .target         = acpi_cpufreq_target,
521         .init           = acpi_cpufreq_cpu_init,
522         .exit           = acpi_cpufreq_cpu_exit,
523         .resume         = acpi_cpufreq_resume,
524         .name           = "acpi-cpufreq",
525         .owner          = THIS_MODULE,
526         .attr           = acpi_cpufreq_attr,
527 };
528
529
530 static int __init
531 acpi_cpufreq_init (void)
532 {
533         int                     result = 0;
534
535         dprintk("acpi_cpufreq_init\n");
536
537         result = cpufreq_register_driver(&acpi_cpufreq_driver);
538         
539         return (result);
540 }
541
542
543 static void __exit
544 acpi_cpufreq_exit (void)
545 {
546         dprintk("acpi_cpufreq_exit\n");
547
548         cpufreq_unregister_driver(&acpi_cpufreq_driver);
549
550         return;
551 }
552
553 module_param(acpi_pstate_strict, uint, 0644);
554 MODULE_PARM_DESC(acpi_pstate_strict, "value 0 or non-zero. non-zero -> strict ACPI checks are performed during frequency changes.");
555
556 late_initcall(acpi_cpufreq_init);
557 module_exit(acpi_cpufreq_exit);
558
559 MODULE_ALIAS("acpi");