summaryrefslogtreecommitdiff
path: root/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c
blob: 05668e3598c030e739fa03db88d47553017b57ad (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
/*
 * acpi-cpufreq.c - ACPI Processor P-States Driver ($Revision: 1.3 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *  Copyright (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/compiler.h>
#include <linux/sched.h>	/* current */
#include <asm/io.h>
#include <asm/delay.h>
#include <asm/uaccess.h>

#include <linux/acpi.h>
#include <acpi/processor.h>

#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)

MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
MODULE_DESCRIPTION("ACPI Processor P-States Driver");
MODULE_LICENSE("GPL");


struct cpufreq_acpi_io {
	struct acpi_processor_performance	*acpi_data;
	struct cpufreq_frequency_table		*freq_table;
	unsigned int				resume;
};

static struct cpufreq_acpi_io	*acpi_io_data[NR_CPUS];
static struct acpi_processor_performance	*acpi_perf_data[NR_CPUS];

static struct cpufreq_driver acpi_cpufreq_driver;

static unsigned int acpi_pstate_strict;

static int
acpi_processor_write_port(
	u16	port,
	u8	bit_width,
	u32	value)
{
	if (bit_width <= 8) {
		outb(value, port);
	} else if (bit_width <= 16) {
		outw(value, port);
	} else if (bit_width <= 32) {
		outl(value, port);
	} else {
		return -ENODEV;
	}
	return 0;
}

static int
acpi_processor_read_port(
	u16	port,
	u8	bit_width,
	u32	*ret)
{
	*ret = 0;
	if (bit_width <= 8) {
		*ret = inb(port);
	} else if (bit_width <= 16) {
		*ret = inw(port);
	} else if (bit_width <= 32) {
		*ret = inl(port);
	} else {
		return -ENODEV;
	}
	return 0;
}

static int
acpi_processor_set_performance (
	struct cpufreq_acpi_io	*data,
	unsigned int		cpu,
	int			state)
{
	u16			port = 0;
	u8			bit_width = 0;
	int			i = 0;
	int			ret = 0;
	u32			value = 0;
	int			retval;
	struct acpi_processor_performance	*perf;

	dprintk("acpi_processor_set_performance\n");

	retval = 0;
	perf = data->acpi_data;	
	if (state == perf->state) {
		if (unlikely(data->resume)) {
			dprintk("Called after resume, resetting to P%d\n", state);
			data->resume = 0;
		} else {
			dprintk("Already at target state (P%d)\n", state);
			return (retval);
		}
	}

	dprintk("Transitioning from P%d to P%d\n", perf->state, state);

	/*
	 * First we write the target state's 'control' value to the
	 * control_register.
	 */

	port = perf->control_register.address;
	bit_width = perf->control_register.bit_width;
	value = (u32) perf->states[state].control;

	dprintk("Writing 0x%08x to port 0x%04x\n", value, port);

	ret = acpi_processor_write_port(port, bit_width, value);
	if (ret) {
		dprintk("Invalid port width 0x%04x\n", bit_width);
		return (ret);
	}

	/*
	 * Assume the write went through when acpi_pstate_strict is not used.
	 * As read status_register is an expensive operation and there 
	 * are no specific error cases where an IO port write will fail.
	 */
	if (acpi_pstate_strict) {
		/* Then we read the 'status_register' and compare the value 
		 * with the target state's 'status' to make sure the 
		 * transition was successful.
		 * Note that we'll poll for up to 1ms (100 cycles of 10us) 
		 * before giving up.
		 */

		port = perf->status_register.address;
		bit_width = perf->status_register.bit_width;

		dprintk("Looking for 0x%08x from port 0x%04x\n",
			(u32) perf->states[state].status, port);

		for (i = 0; i < 100; i++) {
			ret = acpi_processor_read_port(port, bit_width, &value);
			if (ret) {	
				dprintk("Invalid port width 0x%04x\n", bit_width);
				return (ret);
			}
			if (value == (u32) perf->states[state].status)
				break;
			udelay(10);
		}
	} else {
		value = (u32) perf->states[state].status;
	}

	if (unlikely(value != (u32) perf->states[state].status)) {
		printk(KERN_WARNING "acpi-cpufreq: Transition failed\n");
		retval = -ENODEV;
		return (retval);
	}

	dprintk("Transition successful after %d microseconds\n", i * 10);

	perf->state = state;
	return (retval);
}


static int
acpi_cpufreq_target (
	struct cpufreq_policy   *policy,
	unsigned int target_freq,
	unsigned int relation)
{
	struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
	struct acpi_processor_performance *perf;
	struct cpufreq_freqs freqs;
	cpumask_t online_policy_cpus;
	cpumask_t saved_mask;
	cpumask_t set_mask;
	cpumask_t covered_cpus;
	unsigned int cur_state = 0;
	unsigned int next_state = 0;
	unsigned int result = 0;
	unsigned int j;
	unsigned int tmp;

	dprintk("acpi_cpufreq_setpolicy\n");

	result = cpufreq_frequency_table_target(policy,
			data->freq_table,
			target_freq,
			relation,
			&next_state);
	if (unlikely(result))
		return (result);

	perf = data->acpi_data;
	cur_state = perf->state;
	freqs.old = data->freq_table[cur_state].frequency;
	freqs.new = data->freq_table[next_state].frequency;

#ifdef CONFIG_HOTPLUG_CPU
	/* cpufreq holds the hotplug lock, so we are safe from here on */
	cpus_and(online_policy_cpus, cpu_online_map, policy->cpus);
#else
	online_policy_cpus = policy->cpus;
#endif

	for_each_cpu_mask(j, online_policy_cpus) {
		freqs.cpu = j;
		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	}

	/*
	 * We need to call driver->target() on all or any CPU in
	 * policy->cpus, depending on policy->shared_type.
	 */
	saved_mask = current->cpus_allowed;
	cpus_clear(covered_cpus);
	for_each_cpu_mask(j, online_policy_cpus) {
		/*
		 * Support for SMP systems.
		 * Make sure we are running on CPU that wants to change freq
		 */
		cpus_clear(set_mask);
		if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
			cpus_or(set_mask, set_mask, online_policy_cpus);
		else
			cpu_set(j, set_mask);

		set_cpus_allowed(current, set_mask);
		if (unlikely(!cpu_isset(smp_processor_id(), set_mask))) {
			dprintk("couldn't limit to CPUs in this domain\n");
			result = -EAGAIN;
			break;
		}

		result = acpi_processor_set_performance (data, j, next_state);
		if (result) {
			result = -EAGAIN;
			break;
		}

		if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
			break;
 
		cpu_set(j, covered_cpus);
	}

	for_each_cpu_mask(j, online_policy_cpus) {
		freqs.cpu = j;
		cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
	}

	if (unlikely(result)) {
		/*
		 * We have failed halfway through the frequency change.
		 * We have sent callbacks to online_policy_cpus and
		 * acpi_processor_set_performance() has been called on 
		 * coverd_cpus. Best effort undo..
		 */

		if (!cpus_empty(covered_cpus)) {
			for_each_cpu_mask(j, covered_cpus) {
				policy->cpu = j;
				acpi_processor_set_performance (data, 
						j, 
						cur_state);
			}
		}

		tmp = freqs.new;
		freqs.new = freqs.old;
		freqs.old = tmp;
		for_each_cpu_mask(j, online_policy_cpus) {
			freqs.cpu = j;
			cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
			cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
		}
	}

	set_cpus_allowed(current, saved_mask);
	return (result);
}


static int
acpi_cpufreq_verify (
	struct cpufreq_policy   *policy)
{
	unsigned int result = 0;
	struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];

	dprintk("acpi_cpufreq_verify\n");

	result = cpufreq_frequency_table_verify(policy, 
			data->freq_table);

	return (result);
}


static unsigned long
acpi_cpufreq_guess_freq (
	struct cpufreq_acpi_io	*data,
	unsigned int		cpu)
{
	struct acpi_processor_performance	*perf = data->acpi_data;

	if (cpu_khz) {
		/* search the closest match to cpu_khz */
		unsigned int i;
		unsigned long freq;
		unsigned long freqn = perf->states[0].core_frequency * 1000;

		for (i = 0; i < (perf->state_count - 1); i++) {
			freq = freqn;
			freqn = perf->states[i+1].core_frequency * 1000;
			if ((2 * cpu_khz) > (freqn + freq)) {
				perf->state = i;
				return (freq);
			}
		}
		perf->state = perf->state_count - 1;
		return (freqn);
	} else {
		/* assume CPU is at P0... */
		perf->state = 0;
		return perf->states[0].core_frequency * 1000;
	}
}


/*
 * acpi_cpufreq_early_init - initialize ACPI P-States library
 *
 * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
 * in order to determine correct frequency and voltage pairings. We can
 * do _PDC and _PSD and find out the processor dependency for the
 * actual init that will happen later...
 */
static int acpi_cpufreq_early_init_acpi(void)
{
	struct acpi_processor_performance	*data;
	unsigned int				i, j;

	dprintk("acpi_cpufreq_early_init\n");

	for_each_cpu(i) {
		data = kzalloc(sizeof(struct acpi_processor_performance), 
			GFP_KERNEL);
		if (!data) {
			for_each_cpu(j) {
				kfree(acpi_perf_data[j]);
				acpi_perf_data[j] = NULL;
			}
			return (-ENOMEM);
		}
		acpi_perf_data[i] = data;
	}

	/* Do initialization in ACPI core */
	acpi_processor_preregister_performance(acpi_perf_data);
	return 0;
}

static int
acpi_cpufreq_cpu_init (
	struct cpufreq_policy   *policy)
{
	unsigned int		i;
	unsigned int		cpu = policy->cpu;
	struct cpufreq_acpi_io	*data;
	unsigned int		result = 0;
	struct cpuinfo_x86 *c = &cpu_data[policy->cpu];
	struct acpi_processor_performance	*perf;

	dprintk("acpi_cpufreq_cpu_init\n");

	if (!acpi_perf_data[cpu])
		return (-ENODEV);

	data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
	if (!data)
		return (-ENOMEM);

	data->acpi_data = acpi_perf_data[cpu];
	acpi_io_data[cpu] = data;

	result = acpi_processor_register_performance(data->acpi_data, cpu);

	if (result)
		goto err_free;

	perf = data->acpi_data;
	policy->cpus = perf->shared_cpu_map;
	policy->shared_type = perf->shared_type;

	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
		acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
	}

	/* capability check */
	if (perf->state_count <= 1) {
		dprintk("No P-States\n");
		result = -ENODEV;
		goto err_unreg;
	}

	if ((perf->control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
	    (perf->status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
		dprintk("Unsupported address space [%d, %d]\n",
			(u32) (perf->control_register.space_id),
			(u32) (perf->status_register.space_id));
		result = -ENODEV;
		goto err_unreg;
	}

	/* alloc freq_table */
	data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (perf->state_count + 1), GFP_KERNEL);
	if (!data->freq_table) {
		result = -ENOMEM;
		goto err_unreg;
	}

	/* detect transition latency */
	policy->cpuinfo.transition_latency = 0;
	for (i=0; i<perf->state_count; i++) {
		if ((perf->states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
			policy->cpuinfo.transition_latency = perf->states[i].transition_latency * 1000;
	}
	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;

	/* The current speed is unknown and not detectable by ACPI...  */
	policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);

	/* table init */
	for (i=0; i<=perf->state_count; i++)
	{
		data->freq_table[i].index = i;
		if (i<perf->state_count)
			data->freq_table[i].frequency = perf->states[i].core_frequency * 1000;
		else
			data->freq_table[i].frequency = CPUFREQ_TABLE_END;
	}

	result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
	if (result) {
		goto err_freqfree;
	}

	/* notify BIOS that we exist */
	acpi_processor_notify_smm(THIS_MODULE);

	printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management activated.\n",
	       cpu);
	for (i = 0; i < perf->state_count; i++)
		dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
			(i == perf->state?'*':' '), i,
			(u32) perf->states[i].core_frequency,
			(u32) perf->states[i].power,
			(u32) perf->states[i].transition_latency);

	cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
	
	/*
	 * the first call to ->target() should result in us actually
	 * writing something to the appropriate registers.
	 */
	data->resume = 1;
	
	return (result);

 err_freqfree:
	kfree(data->freq_table);
 err_unreg:
	acpi_processor_unregister_performance(perf, cpu);
 err_free:
	kfree(data);
	acpi_io_data[cpu] = NULL;

	return (result);
}


static int
acpi_cpufreq_cpu_exit (
	struct cpufreq_policy   *policy)
{
	struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];


	dprintk("acpi_cpufreq_cpu_exit\n");

	if (data) {
		cpufreq_frequency_table_put_attr(policy->cpu);
		acpi_io_data[policy->cpu] = NULL;
		acpi_processor_unregister_performance(data->acpi_data, policy->cpu);
		kfree(data);
	}

	return (0);
}

static int
acpi_cpufreq_resume (
	struct cpufreq_policy   *policy)
{
	struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];


	dprintk("acpi_cpufreq_resume\n");

	data->resume = 1;

	return (0);
}


static struct freq_attr* acpi_cpufreq_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
};

static struct cpufreq_driver acpi_cpufreq_driver = {
	.verify	= acpi_cpufreq_verify,
	.target	= acpi_cpufreq_target,
	.init	= acpi_cpufreq_cpu_init,
	.exit	= acpi_cpufreq_cpu_exit,
	.resume	= acpi_cpufreq_resume,
	.name	= "acpi-cpufreq",
	.owner	= THIS_MODULE,
	.attr	= acpi_cpufreq_attr,
	.flags	= CPUFREQ_STICKY,
};


static int __init
acpi_cpufreq_init (void)
{
	int                     result = 0;

	dprintk("acpi_cpufreq_init\n");

	result = acpi_cpufreq_early_init_acpi();

	if (!result)
 		result = cpufreq_register_driver(&acpi_cpufreq_driver);
	
	return (result);
}


static void __exit
acpi_cpufreq_exit (void)
{
	unsigned int	i;
	dprintk("acpi_cpufreq_exit\n");

	cpufreq_unregister_driver(&acpi_cpufreq_driver);

	for_each_cpu(i) {
		kfree(acpi_perf_data[i]);
		acpi_perf_data[i] = NULL;
	}
	return;
}

module_param(acpi_pstate_strict, uint, 0644);
MODULE_PARM_DESC(acpi_pstate_strict, "value 0 or non-zero. non-zero -> strict ACPI checks are performed during frequency changes.");

late_initcall(acpi_cpufreq_init);
module_exit(acpi_cpufreq_exit);

MODULE_ALIAS("acpi");