summaryrefslogtreecommitdiffstats
path: root/arch/ia64/kernel/cpufreq/acpi-cpufreq.c
blob: da4d5cf80a480eb5b4be0518240db04e44776cf0 (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
/*
 * arch/ia64/kernel/cpufreq/acpi-cpufreq.c
 * This file provides the ACPI based P-state support. This
 * module works with generic cpufreq infrastructure. Most of
 * the code is based on i386 version
 * (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c)
 *
 * Copyright (C) 2005 Intel Corp
 *      Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 */

#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 <asm/io.h>
#include <asm/uaccess.h>
#include <asm/pal.h>

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

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

MODULE_AUTHOR("Venkatesh Pallipadi");
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 cpufreq_driver acpi_cpufreq_driver;


static int
processor_set_pstate (
	u32	value)
{
	s64 retval;

	dprintk("processor_set_pstate\n");

	retval = ia64_pal_set_pstate((u64)value);

	if (retval) {
		dprintk("Failed to set freq to 0x%x, with error 0x%x\n",
		        value, retval);
		return -ENODEV;
	}
	return (int)retval;
}


static int
processor_get_pstate (
	u32	*value)
{
	u64	pstate_index = 0;
	s64 	retval;

	dprintk("processor_get_pstate\n");

	retval = ia64_pal_get_pstate(&pstate_index);
	*value = (u32) pstate_index;

	if (retval)
		dprintk("Failed to get current freq with "
		        "error 0x%x, idx 0x%x\n", retval, *value);

	return (int)retval;
}


/* To be used only after data->acpi_data is initialized */
static unsigned
extract_clock (
	struct cpufreq_acpi_io *data,
	unsigned value,
	unsigned int cpu)
{
	unsigned long i;

	dprintk("extract_clock\n");

	for (i = 0; i < data->acpi_data.state_count; i++) {
		if (value >= data->acpi_data.states[i].control)
			return data->acpi_data.states[i].core_frequency;
	}
	return data->acpi_data.states[i-1].core_frequency;
}


static unsigned int
processor_get_freq (
	struct cpufreq_acpi_io	*data,
	unsigned int		cpu)
{
	int			ret = 0;
	u32			value = 0;
	cpumask_t		saved_mask;
	unsigned long 		clock_freq;

	dprintk("processor_get_freq\n");

	saved_mask = current->cpus_allowed;
	set_cpus_allowed(current, cpumask_of_cpu(cpu));
	if (smp_processor_id() != cpu) {
		ret = -EAGAIN;
		goto migrate_end;
	}

	/*
	 * processor_get_pstate gets the average frequency since the
	 * last get. So, do two PAL_get_freq()...
	 */
	ret = processor_get_pstate(&value);
	ret = processor_get_pstate(&value);

	if (ret) {
		set_cpus_allowed(current, saved_mask);
		printk(KERN_WARNING "get performance failed with error %d\n",
		       ret);
		ret = -EAGAIN;
		goto migrate_end;
	}
	clock_freq = extract_clock(data, value, cpu);
	ret = (clock_freq*1000);

migrate_end:
	set_cpus_allowed(current, saved_mask);
	return ret;
}


static int
processor_set_freq (
	struct cpufreq_acpi_io	*data,
	unsigned int		cpu,
	int			state)
{
	int			ret = 0;
	u32			value = 0;
	struct cpufreq_freqs    cpufreq_freqs;
	cpumask_t		saved_mask;
	int			retval;

	dprintk("processor_set_freq\n");

	saved_mask = current->cpus_allowed;
	set_cpus_allowed(current, cpumask_of_cpu(cpu));
	if (smp_processor_id() != cpu) {
		retval = -EAGAIN;
		goto migrate_end;
	}

	if (state == data->acpi_data.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);
			retval = 0;
			goto migrate_end;
		}
	}

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

	/* cpufreq frequency struct */
	cpufreq_freqs.cpu = cpu;
	cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
	cpufreq_freqs.new = data->freq_table[state].frequency;

	/* notify cpufreq */
	cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);

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

	value = (u32) data->acpi_data.states[state].control;

	dprintk("Transitioning to state: 0x%08x\n", value);

	ret = processor_set_pstate(value);
	if (ret) {
		unsigned int tmp = cpufreq_freqs.new;
		cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
		cpufreq_freqs.new = cpufreq_freqs.old;
		cpufreq_freqs.old = tmp;
		cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
		cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
		printk(KERN_WARNING "Transition failed with error %d\n", ret);
		retval = -ENODEV;
		goto migrate_end;
	}

	cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);

	data->acpi_data.state = state;

	retval = 0;

migrate_end:
	set_cpus_allowed(current, saved_mask);
	return (retval);
}


static unsigned int
acpi_cpufreq_get (
	unsigned int		cpu)
{
	struct cpufreq_acpi_io *data = acpi_io_data[cpu];

	dprintk("acpi_cpufreq_get\n");

	return processor_get_freq(data, cpu);
}


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];
	unsigned int next_state = 0;
	unsigned int result = 0;

	dprintk("acpi_cpufreq_setpolicy\n");

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

	result = processor_set_freq(data, policy->cpu, next_state);

	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);
}


/*
 * processor_init_pdc - let BIOS know about the SMP capabilities
 * of this driver
 * @perf: processor-specific acpi_io_data struct
 * @cpu: CPU being initialized
 *
 * To avoid issues with legacy OSes, some BIOSes require to be informed of
 * the SMP capabilities of OS P-state driver. Here we set the bits in _PDC
 * accordingly. Actual call to _PDC is done in driver/acpi/processor.c
 */
static void
processor_init_pdc (
		struct acpi_processor_performance *perf,
		unsigned int cpu,
		struct acpi_object_list *obj_list
		)
{
	union acpi_object *obj;
	u32 *buf;

	dprintk("processor_init_pdc\n");

	perf->pdc = NULL;
	/* Initialize pdc. It will be used later. */
	if (!obj_list)
		return;

	if (!(obj_list->count && obj_list->pointer))
		return;

	obj = obj_list->pointer;
	if ((obj->buffer.length == 12) && obj->buffer.pointer) {
		buf = (u32 *)obj->buffer.pointer;
       		buf[0] = ACPI_PDC_REVISION_ID;
       		buf[1] = 1;
       		buf[2] = ACPI_PDC_EST_CAPABILITY_SMP;
		perf->pdc = obj_list;
	}
	return;
}


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;

	union acpi_object		arg0 = {ACPI_TYPE_BUFFER};
	u32				arg0_buf[3];
	struct acpi_object_list 	arg_list = {1, &arg0};

	dprintk("acpi_cpufreq_cpu_init\n");
	/* setup arg_list for _PDC settings */
        arg0.buffer.length = 12;
        arg0.buffer.pointer = (u8 *) arg0_buf;

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

	memset(data, 0, sizeof(struct cpufreq_acpi_io));

	acpi_io_data[cpu] = data;

	processor_init_pdc(&data->acpi_data, cpu, &arg_list);
	result = acpi_processor_register_performance(&data->acpi_data, cpu);
	data->acpi_data.pdc = NULL;

	if (result)
		goto err_free;

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

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

	/* alloc freq_table */
	data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
	                           (data->acpi_data.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<data->acpi_data.state_count; i++) {
		if ((data->acpi_data.states[i].transition_latency * 1000) >
		    policy->cpuinfo.transition_latency) {
			policy->cpuinfo.transition_latency =
			    data->acpi_data.states[i].transition_latency * 1000;
		}
	}
	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;

	policy->cur = processor_get_freq(data, policy->cpu);

	/* table init */
	for (i = 0; i <= data->acpi_data.state_count; i++)
	{
		data->freq_table[i].index = i;
		if (i < data->acpi_data.state_count) {
			data->freq_table[i].frequency =
			      data->acpi_data.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 < data->acpi_data.state_count; i++)
		dprintk("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
			(i == data->acpi_data.state?'*':' '), i,
			(u32) data->acpi_data.states[i].core_frequency,
			(u32) data->acpi_data.states[i].power,
			(u32) data->acpi_data.states[i].transition_latency,
			(u32) data->acpi_data.states[i].bus_master_latency,
			(u32) data->acpi_data.states[i].status,
			(u32) data->acpi_data.states[i].control);

	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(&data->acpi_data, 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 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,
	.get 		= acpi_cpufreq_get,
	.init		= acpi_cpufreq_cpu_init,
	.exit		= acpi_cpufreq_cpu_exit,
	.name		= "acpi-cpufreq",
	.owner		= THIS_MODULE,
	.attr           = acpi_cpufreq_attr,
};


static int __init
acpi_cpufreq_init (void)
{
	dprintk("acpi_cpufreq_init\n");

 	return cpufreq_register_driver(&acpi_cpufreq_driver);
}


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

	cpufreq_unregister_driver(&acpi_cpufreq_driver);
	return;
}


late_initcall(acpi_cpufreq_init);
module_exit(acpi_cpufreq_exit);