1 /*
2  * processor_perflib.c - ACPI Processor P-States Library ($Revision: 71 $)
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) 2004       Dominik Brodowski <linux@brodo.de>
7  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
8  *  			- Added processor hotplug support
9  *
10  *
11  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
12  *
13  *  This program is free software; you can redistribute it and/or modify
14  *  it under the terms of the GNU General Public License as published by
15  *  the Free Software Foundation; either version 2 of the License, or (at
16  *  your option) any later version.
17  *
18  *  This program is distributed in the hope that it will be useful, but
19  *  WITHOUT ANY WARRANTY; without even the implied warranty of
20  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21  *  General Public License for more details.
22  *
23  *  You should have received a copy of the GNU General Public License along
24  *  with this program; if not, write to the Free Software Foundation, Inc.,
25  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
26  *
27  */
28 
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/init.h>
32 #include <linux/cpufreq.h>
33 
34 #ifdef CONFIG_X86
35 #include <asm/cpufeature.h>
36 #endif
37 
38 #include <acpi/acpi_bus.h>
39 #include <acpi/acpi_drivers.h>
40 #include <acpi/processor.h>
41 
42 #define ACPI_PROCESSOR_CLASS		"processor"
43 #define ACPI_PROCESSOR_FILE_PERFORMANCE	"performance"
44 #define _COMPONENT		ACPI_PROCESSOR_COMPONENT
45 ACPI_MODULE_NAME("processor_perflib");
46 
47 static DEFINE_MUTEX(performance_mutex);
48 
49 /* Use cpufreq debug layer for _PPC changes. */
50 #define cpufreq_printk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_CORE, \
51 						"cpufreq-core", msg)
52 
53 /*
54  * _PPC support is implemented as a CPUfreq policy notifier:
55  * This means each time a CPUfreq driver registered also with
56  * the ACPI core is asked to change the speed policy, the maximum
57  * value is adjusted so that it is within the platform limit.
58  *
59  * Also, when a new platform limit value is detected, the CPUfreq
60  * policy is adjusted accordingly.
61  */
62 
63 /* ignore_ppc:
64  * -1 -> cpufreq low level drivers not initialized -> _PSS, etc. not called yet
65  *       ignore _PPC
66  *  0 -> cpufreq low level drivers initialized -> consider _PPC values
67  *  1 -> ignore _PPC totally -> forced by user through boot param
68  */
69 static int ignore_ppc = -1;
70 module_param(ignore_ppc, int, 0644);
71 MODULE_PARM_DESC(ignore_ppc, "If the frequency of your machine gets wrongly" \
72 		 "limited by BIOS, this should help");
73 
74 #define PPC_REGISTERED   1
75 #define PPC_IN_USE       2
76 
77 static int acpi_processor_ppc_status;
78 
79 static int acpi_processor_ppc_notifier(struct notifier_block *nb,
80 				       unsigned long event, void *data)
81 {
82 	struct cpufreq_policy *policy = data;
83 	struct acpi_processor *pr;
84 	unsigned int ppc = 0;
85 
86 	if (event == CPUFREQ_START && ignore_ppc <= 0) {
87 		ignore_ppc = 0;
88 		return 0;
89 	}
90 
91 	if (ignore_ppc)
92 		return 0;
93 
94 	if (event != CPUFREQ_INCOMPATIBLE)
95 		return 0;
96 
97 	mutex_lock(&performance_mutex);
98 
99 	pr = per_cpu(processors, policy->cpu);
100 	if (!pr || !pr->performance)
101 		goto out;
102 
103 	ppc = (unsigned int)pr->performance_platform_limit;
104 
105 	if (ppc >= pr->performance->state_count)
106 		goto out;
107 
108 	cpufreq_verify_within_limits(policy, 0,
109 				     pr->performance->states[ppc].
110 				     core_frequency * 1000);
111 
112       out:
113 	mutex_unlock(&performance_mutex);
114 
115 	return 0;
116 }
117 
118 static struct notifier_block acpi_ppc_notifier_block = {
119 	.notifier_call = acpi_processor_ppc_notifier,
120 };
121 
122 static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
123 {
124 	acpi_status status = 0;
125 	unsigned long long ppc = 0;
126 
127 
128 	if (!pr)
129 		return -EINVAL;
130 
131 	/*
132 	 * _PPC indicates the maximum state currently supported by the platform
133 	 * (e.g. 0 = states 0..n; 1 = states 1..n; etc.
134 	 */
135 	status = acpi_evaluate_integer(pr->handle, "_PPC", NULL, &ppc);
136 
137 	if (status != AE_NOT_FOUND)
138 		acpi_processor_ppc_status |= PPC_IN_USE;
139 
140 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
141 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PPC"));
142 		return -ENODEV;
143 	}
144 
145 	cpufreq_printk("CPU %d: _PPC is %d - frequency %s limited\n", pr->id,
146 		       (int)ppc, ppc ? "" : "not");
147 
148 	pr->performance_platform_limit = (int)ppc;
149 
150 	return 0;
151 }
152 
153 int acpi_processor_ppc_has_changed(struct acpi_processor *pr)
154 {
155 	int ret;
156 
157 	if (ignore_ppc)
158 		return 0;
159 
160 	ret = acpi_processor_get_platform_limit(pr);
161 
162 	if (ret < 0)
163 		return (ret);
164 	else
165 		return cpufreq_update_policy(pr->id);
166 }
167 
168 void acpi_processor_ppc_init(void)
169 {
170 	if (!cpufreq_register_notifier
171 	    (&acpi_ppc_notifier_block, CPUFREQ_POLICY_NOTIFIER))
172 		acpi_processor_ppc_status |= PPC_REGISTERED;
173 	else
174 		printk(KERN_DEBUG
175 		       "Warning: Processor Platform Limit not supported.\n");
176 }
177 
178 void acpi_processor_ppc_exit(void)
179 {
180 	if (acpi_processor_ppc_status & PPC_REGISTERED)
181 		cpufreq_unregister_notifier(&acpi_ppc_notifier_block,
182 					    CPUFREQ_POLICY_NOTIFIER);
183 
184 	acpi_processor_ppc_status &= ~PPC_REGISTERED;
185 }
186 
187 static int acpi_processor_get_performance_control(struct acpi_processor *pr)
188 {
189 	int result = 0;
190 	acpi_status status = 0;
191 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
192 	union acpi_object *pct = NULL;
193 	union acpi_object obj = { 0 };
194 
195 
196 	status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);
197 	if (ACPI_FAILURE(status)) {
198 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PCT"));
199 		return -ENODEV;
200 	}
201 
202 	pct = (union acpi_object *)buffer.pointer;
203 	if (!pct || (pct->type != ACPI_TYPE_PACKAGE)
204 	    || (pct->package.count != 2)) {
205 		printk(KERN_ERR PREFIX "Invalid _PCT data\n");
206 		result = -EFAULT;
207 		goto end;
208 	}
209 
210 	/*
211 	 * control_register
212 	 */
213 
214 	obj = pct->package.elements[0];
215 
216 	if ((obj.type != ACPI_TYPE_BUFFER)
217 	    || (obj.buffer.length < sizeof(struct acpi_pct_register))
218 	    || (obj.buffer.pointer == NULL)) {
219 		printk(KERN_ERR PREFIX "Invalid _PCT data (control_register)\n");
220 		result = -EFAULT;
221 		goto end;
222 	}
223 	memcpy(&pr->performance->control_register, obj.buffer.pointer,
224 	       sizeof(struct acpi_pct_register));
225 
226 	/*
227 	 * status_register
228 	 */
229 
230 	obj = pct->package.elements[1];
231 
232 	if ((obj.type != ACPI_TYPE_BUFFER)
233 	    || (obj.buffer.length < sizeof(struct acpi_pct_register))
234 	    || (obj.buffer.pointer == NULL)) {
235 		printk(KERN_ERR PREFIX "Invalid _PCT data (status_register)\n");
236 		result = -EFAULT;
237 		goto end;
238 	}
239 
240 	memcpy(&pr->performance->status_register, obj.buffer.pointer,
241 	       sizeof(struct acpi_pct_register));
242 
243       end:
244 	kfree(buffer.pointer);
245 
246 	return result;
247 }
248 
249 static int acpi_processor_get_performance_states(struct acpi_processor *pr)
250 {
251 	int result = 0;
252 	acpi_status status = AE_OK;
253 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
254 	struct acpi_buffer format = { sizeof("NNNNNN"), "NNNNNN" };
255 	struct acpi_buffer state = { 0, NULL };
256 	union acpi_object *pss = NULL;
257 	int i;
258 
259 
260 	status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);
261 	if (ACPI_FAILURE(status)) {
262 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PSS"));
263 		return -ENODEV;
264 	}
265 
266 	pss = buffer.pointer;
267 	if (!pss || (pss->type != ACPI_TYPE_PACKAGE)) {
268 		printk(KERN_ERR PREFIX "Invalid _PSS data\n");
269 		result = -EFAULT;
270 		goto end;
271 	}
272 
273 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d performance states\n",
274 			  pss->package.count));
275 
276 	pr->performance->state_count = pss->package.count;
277 	pr->performance->states =
278 	    kmalloc(sizeof(struct acpi_processor_px) * pss->package.count,
279 		    GFP_KERNEL);
280 	if (!pr->performance->states) {
281 		result = -ENOMEM;
282 		goto end;
283 	}
284 
285 	for (i = 0; i < pr->performance->state_count; i++) {
286 
287 		struct acpi_processor_px *px = &(pr->performance->states[i]);
288 
289 		state.length = sizeof(struct acpi_processor_px);
290 		state.pointer = px;
291 
292 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));
293 
294 		status = acpi_extract_package(&(pss->package.elements[i]),
295 					      &format, &state);
296 		if (ACPI_FAILURE(status)) {
297 			ACPI_EXCEPTION((AE_INFO, status, "Invalid _PSS data"));
298 			result = -EFAULT;
299 			kfree(pr->performance->states);
300 			goto end;
301 		}
302 
303 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
304 				  "State [%d]: core_frequency[%d] power[%d] transition_latency[%d] bus_master_latency[%d] control[0x%x] status[0x%x]\n",
305 				  i,
306 				  (u32) px->core_frequency,
307 				  (u32) px->power,
308 				  (u32) px->transition_latency,
309 				  (u32) px->bus_master_latency,
310 				  (u32) px->control, (u32) px->status));
311 
312 		/*
313  		 * Check that ACPI's u64 MHz will be valid as u32 KHz in cpufreq
314 		 */
315 		if (!px->core_frequency ||
316 		    ((u32)(px->core_frequency * 1000) !=
317 		     (px->core_frequency * 1000))) {
318 			printk(KERN_ERR FW_BUG PREFIX
319 			       "Invalid BIOS _PSS frequency: 0x%llx MHz\n",
320 			       px->core_frequency);
321 			result = -EFAULT;
322 			kfree(pr->performance->states);
323 			goto end;
324 		}
325 	}
326 
327       end:
328 	kfree(buffer.pointer);
329 
330 	return result;
331 }
332 
333 static int acpi_processor_get_performance_info(struct acpi_processor *pr)
334 {
335 	int result = 0;
336 	acpi_status status = AE_OK;
337 	acpi_handle handle = NULL;
338 
339 	if (!pr || !pr->performance || !pr->handle)
340 		return -EINVAL;
341 
342 	status = acpi_get_handle(pr->handle, "_PCT", &handle);
343 	if (ACPI_FAILURE(status)) {
344 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
345 				  "ACPI-based processor performance control unavailable\n"));
346 		return -ENODEV;
347 	}
348 
349 	result = acpi_processor_get_performance_control(pr);
350 	if (result)
351 		goto update_bios;
352 
353 	result = acpi_processor_get_performance_states(pr);
354 	if (result)
355 		goto update_bios;
356 
357 	return 0;
358 
359 	/*
360 	 * Having _PPC but missing frequencies (_PSS, _PCT) is a very good hint that
361 	 * the BIOS is older than the CPU and does not know its frequencies
362 	 */
363  update_bios:
364 #ifdef CONFIG_X86
365 	if (ACPI_SUCCESS(acpi_get_handle(pr->handle, "_PPC", &handle))){
366 		if(boot_cpu_has(X86_FEATURE_EST))
367 			printk(KERN_WARNING FW_BUG "BIOS needs update for CPU "
368 			       "frequency support\n");
369 	}
370 #endif
371 	return result;
372 }
373 
374 int acpi_processor_notify_smm(struct module *calling_module)
375 {
376 	acpi_status status;
377 	static int is_done = 0;
378 
379 
380 	if (!(acpi_processor_ppc_status & PPC_REGISTERED))
381 		return -EBUSY;
382 
383 	if (!try_module_get(calling_module))
384 		return -EINVAL;
385 
386 	/* is_done is set to negative if an error occured,
387 	 * and to postitive if _no_ error occured, but SMM
388 	 * was already notified. This avoids double notification
389 	 * which might lead to unexpected results...
390 	 */
391 	if (is_done > 0) {
392 		module_put(calling_module);
393 		return 0;
394 	} else if (is_done < 0) {
395 		module_put(calling_module);
396 		return is_done;
397 	}
398 
399 	is_done = -EIO;
400 
401 	/* Can't write pstate_control to smi_command if either value is zero */
402 	if ((!acpi_gbl_FADT.smi_command) || (!acpi_gbl_FADT.pstate_control)) {
403 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No SMI port or pstate_control\n"));
404 		module_put(calling_module);
405 		return 0;
406 	}
407 
408 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
409 			  "Writing pstate_control [0x%x] to smi_command [0x%x]\n",
410 			  acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command));
411 
412 	status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
413 				    (u32) acpi_gbl_FADT.pstate_control, 8);
414 	if (ACPI_FAILURE(status)) {
415 		ACPI_EXCEPTION((AE_INFO, status,
416 				"Failed to write pstate_control [0x%x] to "
417 				"smi_command [0x%x]", acpi_gbl_FADT.pstate_control,
418 				acpi_gbl_FADT.smi_command));
419 		module_put(calling_module);
420 		return status;
421 	}
422 
423 	/* Success. If there's no _PPC, we need to fear nothing, so
424 	 * we can allow the cpufreq driver to be rmmod'ed. */
425 	is_done = 1;
426 
427 	if (!(acpi_processor_ppc_status & PPC_IN_USE))
428 		module_put(calling_module);
429 
430 	return 0;
431 }
432 
433 EXPORT_SYMBOL(acpi_processor_notify_smm);
434 
435 static int acpi_processor_get_psd(struct acpi_processor	*pr)
436 {
437 	int result = 0;
438 	acpi_status status = AE_OK;
439 	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
440 	struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
441 	struct acpi_buffer state = {0, NULL};
442 	union acpi_object  *psd = NULL;
443 	struct acpi_psd_package *pdomain;
444 
445 	status = acpi_evaluate_object(pr->handle, "_PSD", NULL, &buffer);
446 	if (ACPI_FAILURE(status)) {
447 		return -ENODEV;
448 	}
449 
450 	psd = buffer.pointer;
451 	if (!psd || (psd->type != ACPI_TYPE_PACKAGE)) {
452 		printk(KERN_ERR PREFIX "Invalid _PSD data\n");
453 		result = -EFAULT;
454 		goto end;
455 	}
456 
457 	if (psd->package.count != 1) {
458 		printk(KERN_ERR PREFIX "Invalid _PSD data\n");
459 		result = -EFAULT;
460 		goto end;
461 	}
462 
463 	pdomain = &(pr->performance->domain_info);
464 
465 	state.length = sizeof(struct acpi_psd_package);
466 	state.pointer = pdomain;
467 
468 	status = acpi_extract_package(&(psd->package.elements[0]),
469 		&format, &state);
470 	if (ACPI_FAILURE(status)) {
471 		printk(KERN_ERR PREFIX "Invalid _PSD data\n");
472 		result = -EFAULT;
473 		goto end;
474 	}
475 
476 	if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
477 		printk(KERN_ERR PREFIX "Unknown _PSD:num_entries\n");
478 		result = -EFAULT;
479 		goto end;
480 	}
481 
482 	if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
483 		printk(KERN_ERR PREFIX "Unknown _PSD:revision\n");
484 		result = -EFAULT;
485 		goto end;
486 	}
487 
488 	if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
489 	    pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
490 	    pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
491 		printk(KERN_ERR PREFIX "Invalid _PSD:coord_type\n");
492 		result = -EFAULT;
493 		goto end;
494 	}
495 end:
496 	kfree(buffer.pointer);
497 	return result;
498 }
499 
500 int acpi_processor_preregister_performance(
501 		struct acpi_processor_performance *performance)
502 {
503 	int count, count_target;
504 	int retval = 0;
505 	unsigned int i, j;
506 	cpumask_var_t covered_cpus;
507 	struct acpi_processor *pr;
508 	struct acpi_psd_package *pdomain;
509 	struct acpi_processor *match_pr;
510 	struct acpi_psd_package *match_pdomain;
511 
512 	if (!alloc_cpumask_var(&covered_cpus, GFP_KERNEL))
513 		return -ENOMEM;
514 
515 	mutex_lock(&performance_mutex);
516 
517 	/*
518 	 * Check if another driver has already registered, and abort before
519 	 * changing pr->performance if it has. Check input data as well.
520 	 */
521 	for_each_possible_cpu(i) {
522 		pr = per_cpu(processors, i);
523 		if (!pr) {
524 			/* Look only at processors in ACPI namespace */
525 			continue;
526 		}
527 
528 		if (pr->performance) {
529 			retval = -EBUSY;
530 			goto err_out;
531 		}
532 
533 		if (!performance || !per_cpu_ptr(performance, i)) {
534 			retval = -EINVAL;
535 			goto err_out;
536 		}
537 	}
538 
539 	/* Call _PSD for all CPUs */
540 	for_each_possible_cpu(i) {
541 		pr = per_cpu(processors, i);
542 		if (!pr)
543 			continue;
544 
545 		pr->performance = per_cpu_ptr(performance, i);
546 		cpumask_set_cpu(i, pr->performance->shared_cpu_map);
547 		if (acpi_processor_get_psd(pr)) {
548 			retval = -EINVAL;
549 			continue;
550 		}
551 	}
552 	if (retval)
553 		goto err_ret;
554 
555 	/*
556 	 * Now that we have _PSD data from all CPUs, lets setup P-state
557 	 * domain info.
558 	 */
559 	cpumask_clear(covered_cpus);
560 	for_each_possible_cpu(i) {
561 		pr = per_cpu(processors, i);
562 		if (!pr)
563 			continue;
564 
565 		if (cpumask_test_cpu(i, covered_cpus))
566 			continue;
567 
568 		pdomain = &(pr->performance->domain_info);
569 		cpumask_set_cpu(i, pr->performance->shared_cpu_map);
570 		cpumask_set_cpu(i, covered_cpus);
571 		if (pdomain->num_processors <= 1)
572 			continue;
573 
574 		/* Validate the Domain info */
575 		count_target = pdomain->num_processors;
576 		count = 1;
577 		if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
578 			pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
579 		else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
580 			pr->performance->shared_type = CPUFREQ_SHARED_TYPE_HW;
581 		else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
582 			pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ANY;
583 
584 		for_each_possible_cpu(j) {
585 			if (i == j)
586 				continue;
587 
588 			match_pr = per_cpu(processors, j);
589 			if (!match_pr)
590 				continue;
591 
592 			match_pdomain = &(match_pr->performance->domain_info);
593 			if (match_pdomain->domain != pdomain->domain)
594 				continue;
595 
596 			/* Here i and j are in the same domain */
597 
598 			if (match_pdomain->num_processors != count_target) {
599 				retval = -EINVAL;
600 				goto err_ret;
601 			}
602 
603 			if (pdomain->coord_type != match_pdomain->coord_type) {
604 				retval = -EINVAL;
605 				goto err_ret;
606 			}
607 
608 			cpumask_set_cpu(j, covered_cpus);
609 			cpumask_set_cpu(j, pr->performance->shared_cpu_map);
610 			count++;
611 		}
612 
613 		for_each_possible_cpu(j) {
614 			if (i == j)
615 				continue;
616 
617 			match_pr = per_cpu(processors, j);
618 			if (!match_pr)
619 				continue;
620 
621 			match_pdomain = &(match_pr->performance->domain_info);
622 			if (match_pdomain->domain != pdomain->domain)
623 				continue;
624 
625 			match_pr->performance->shared_type =
626 					pr->performance->shared_type;
627 			cpumask_copy(match_pr->performance->shared_cpu_map,
628 				     pr->performance->shared_cpu_map);
629 		}
630 	}
631 
632 err_ret:
633 	for_each_possible_cpu(i) {
634 		pr = per_cpu(processors, i);
635 		if (!pr || !pr->performance)
636 			continue;
637 
638 		/* Assume no coordination on any error parsing domain info */
639 		if (retval) {
640 			cpumask_clear(pr->performance->shared_cpu_map);
641 			cpumask_set_cpu(i, pr->performance->shared_cpu_map);
642 			pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
643 		}
644 		pr->performance = NULL; /* Will be set for real in register */
645 	}
646 
647 err_out:
648 	mutex_unlock(&performance_mutex);
649 	free_cpumask_var(covered_cpus);
650 	return retval;
651 }
652 EXPORT_SYMBOL(acpi_processor_preregister_performance);
653 
654 int
655 acpi_processor_register_performance(struct acpi_processor_performance
656 				    *performance, unsigned int cpu)
657 {
658 	struct acpi_processor *pr;
659 
660 	if (!(acpi_processor_ppc_status & PPC_REGISTERED))
661 		return -EINVAL;
662 
663 	mutex_lock(&performance_mutex);
664 
665 	pr = per_cpu(processors, cpu);
666 	if (!pr) {
667 		mutex_unlock(&performance_mutex);
668 		return -ENODEV;
669 	}
670 
671 	if (pr->performance) {
672 		mutex_unlock(&performance_mutex);
673 		return -EBUSY;
674 	}
675 
676 	WARN_ON(!performance);
677 
678 	pr->performance = performance;
679 
680 	if (acpi_processor_get_performance_info(pr)) {
681 		pr->performance = NULL;
682 		mutex_unlock(&performance_mutex);
683 		return -EIO;
684 	}
685 
686 	mutex_unlock(&performance_mutex);
687 	return 0;
688 }
689 
690 EXPORT_SYMBOL(acpi_processor_register_performance);
691 
692 void
693 acpi_processor_unregister_performance(struct acpi_processor_performance
694 				      *performance, unsigned int cpu)
695 {
696 	struct acpi_processor *pr;
697 
698 	mutex_lock(&performance_mutex);
699 
700 	pr = per_cpu(processors, cpu);
701 	if (!pr) {
702 		mutex_unlock(&performance_mutex);
703 		return;
704 	}
705 
706 	if (pr->performance)
707 		kfree(pr->performance->states);
708 	pr->performance = NULL;
709 
710 	mutex_unlock(&performance_mutex);
711 
712 	return;
713 }
714 
715 EXPORT_SYMBOL(acpi_processor_unregister_performance);
716