Loading...
Note: File does not exist in v3.5.6.
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * acpi_processor.c - ACPI processor enumeration support
4 *
5 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
6 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
7 * Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
8 * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
9 * Copyright (C) 2013, Intel Corporation
10 * Rafael J. Wysocki <rafael.j.wysocki@intel.com>
11 */
12
13#include <linux/acpi.h>
14#include <linux/device.h>
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/pci.h>
18
19#include <acpi/processor.h>
20
21#include <asm/cpu.h>
22
23#include "internal.h"
24
25DEFINE_PER_CPU(struct acpi_processor *, processors);
26EXPORT_PER_CPU_SYMBOL(processors);
27
28/* Errata Handling */
29struct acpi_processor_errata errata __read_mostly;
30EXPORT_SYMBOL_GPL(errata);
31
32static int acpi_processor_errata_piix4(struct pci_dev *dev)
33{
34 u8 value1 = 0;
35 u8 value2 = 0;
36
37
38 if (!dev)
39 return -EINVAL;
40
41 /*
42 * Note that 'dev' references the PIIX4 ACPI Controller.
43 */
44
45 switch (dev->revision) {
46 case 0:
47 dev_dbg(&dev->dev, "Found PIIX4 A-step\n");
48 break;
49 case 1:
50 dev_dbg(&dev->dev, "Found PIIX4 B-step\n");
51 break;
52 case 2:
53 dev_dbg(&dev->dev, "Found PIIX4E\n");
54 break;
55 case 3:
56 dev_dbg(&dev->dev, "Found PIIX4M\n");
57 break;
58 default:
59 dev_dbg(&dev->dev, "Found unknown PIIX4\n");
60 break;
61 }
62
63 switch (dev->revision) {
64
65 case 0: /* PIIX4 A-step */
66 case 1: /* PIIX4 B-step */
67 /*
68 * See specification changes #13 ("Manual Throttle Duty Cycle")
69 * and #14 ("Enabling and Disabling Manual Throttle"), plus
70 * erratum #5 ("STPCLK# Deassertion Time") from the January
71 * 2002 PIIX4 specification update. Applies to only older
72 * PIIX4 models.
73 */
74 errata.piix4.throttle = 1;
75 fallthrough;
76
77 case 2: /* PIIX4E */
78 case 3: /* PIIX4M */
79 /*
80 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
81 * Livelock") from the January 2002 PIIX4 specification update.
82 * Applies to all PIIX4 models.
83 */
84
85 /*
86 * BM-IDE
87 * ------
88 * Find the PIIX4 IDE Controller and get the Bus Master IDE
89 * Status register address. We'll use this later to read
90 * each IDE controller's DMA status to make sure we catch all
91 * DMA activity.
92 */
93 dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
94 PCI_DEVICE_ID_INTEL_82371AB,
95 PCI_ANY_ID, PCI_ANY_ID, NULL);
96 if (dev) {
97 errata.piix4.bmisx = pci_resource_start(dev, 4);
98 pci_dev_put(dev);
99 }
100
101 /*
102 * Type-F DMA
103 * ----------
104 * Find the PIIX4 ISA Controller and read the Motherboard
105 * DMA controller's status to see if Type-F (Fast) DMA mode
106 * is enabled (bit 7) on either channel. Note that we'll
107 * disable C3 support if this is enabled, as some legacy
108 * devices won't operate well if fast DMA is disabled.
109 */
110 dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
111 PCI_DEVICE_ID_INTEL_82371AB_0,
112 PCI_ANY_ID, PCI_ANY_ID, NULL);
113 if (dev) {
114 pci_read_config_byte(dev, 0x76, &value1);
115 pci_read_config_byte(dev, 0x77, &value2);
116 if ((value1 & 0x80) || (value2 & 0x80))
117 errata.piix4.fdma = 1;
118 pci_dev_put(dev);
119 }
120
121 break;
122 }
123
124 if (errata.piix4.bmisx)
125 dev_dbg(&dev->dev, "Bus master activity detection (BM-IDE) erratum enabled\n");
126 if (errata.piix4.fdma)
127 dev_dbg(&dev->dev, "Type-F DMA livelock erratum (C3 disabled)\n");
128
129 return 0;
130}
131
132static int acpi_processor_errata(void)
133{
134 int result = 0;
135 struct pci_dev *dev = NULL;
136
137 /*
138 * PIIX4
139 */
140 dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
141 PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
142 PCI_ANY_ID, NULL);
143 if (dev) {
144 result = acpi_processor_errata_piix4(dev);
145 pci_dev_put(dev);
146 }
147
148 return result;
149}
150
151/* Initialization */
152#ifdef CONFIG_ACPI_HOTPLUG_CPU
153int __weak acpi_map_cpu(acpi_handle handle,
154 phys_cpuid_t physid, u32 acpi_id, int *pcpu)
155{
156 return -ENODEV;
157}
158
159int __weak acpi_unmap_cpu(int cpu)
160{
161 return -ENODEV;
162}
163
164int __weak arch_register_cpu(int cpu)
165{
166 return -ENODEV;
167}
168
169void __weak arch_unregister_cpu(int cpu) {}
170
171static int acpi_processor_hotadd_init(struct acpi_processor *pr)
172{
173 unsigned long long sta;
174 acpi_status status;
175 int ret;
176
177 if (invalid_phys_cpuid(pr->phys_id))
178 return -ENODEV;
179
180 status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
181 if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
182 return -ENODEV;
183
184 cpu_maps_update_begin();
185 cpu_hotplug_begin();
186
187 ret = acpi_map_cpu(pr->handle, pr->phys_id, pr->acpi_id, &pr->id);
188 if (ret)
189 goto out;
190
191 ret = arch_register_cpu(pr->id);
192 if (ret) {
193 acpi_unmap_cpu(pr->id);
194 goto out;
195 }
196
197 /*
198 * CPU got hot-added, but cpu_data is not initialized yet. Set a flag
199 * to delay cpu_idle/throttling initialization and do it when the CPU
200 * gets online for the first time.
201 */
202 pr_info("CPU%d has been hot-added\n", pr->id);
203 pr->flags.need_hotplug_init = 1;
204
205out:
206 cpu_hotplug_done();
207 cpu_maps_update_done();
208 return ret;
209}
210#else
211static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
212{
213 return -ENODEV;
214}
215#endif /* CONFIG_ACPI_HOTPLUG_CPU */
216
217static int acpi_processor_get_info(struct acpi_device *device)
218{
219 union acpi_object object = { 0 };
220 struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
221 struct acpi_processor *pr = acpi_driver_data(device);
222 int device_declaration = 0;
223 acpi_status status = AE_OK;
224 static int cpu0_initialized;
225 unsigned long long value;
226
227 acpi_processor_errata();
228
229 /*
230 * Check to see if we have bus mastering arbitration control. This
231 * is required for proper C3 usage (to maintain cache coherency).
232 */
233 if (acpi_gbl_FADT.pm2_control_block && acpi_gbl_FADT.pm2_control_length) {
234 pr->flags.bm_control = 1;
235 dev_dbg(&device->dev, "Bus mastering arbitration control present\n");
236 } else
237 dev_dbg(&device->dev, "No bus mastering arbitration control\n");
238
239 if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
240 /* Declared with "Processor" statement; match ProcessorID */
241 status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
242 if (ACPI_FAILURE(status)) {
243 dev_err(&device->dev,
244 "Failed to evaluate processor object (0x%x)\n",
245 status);
246 return -ENODEV;
247 }
248
249 pr->acpi_id = object.processor.proc_id;
250 } else {
251 /*
252 * Declared with "Device" statement; match _UID.
253 */
254 status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
255 NULL, &value);
256 if (ACPI_FAILURE(status)) {
257 dev_err(&device->dev,
258 "Failed to evaluate processor _UID (0x%x)\n",
259 status);
260 return -ENODEV;
261 }
262 device_declaration = 1;
263 pr->acpi_id = value;
264 }
265
266 if (acpi_duplicate_processor_id(pr->acpi_id)) {
267 if (pr->acpi_id == 0xff)
268 dev_info_once(&device->dev,
269 "Entry not well-defined, consider updating BIOS\n");
270 else
271 dev_err(&device->dev,
272 "Failed to get unique processor _UID (0x%x)\n",
273 pr->acpi_id);
274 return -ENODEV;
275 }
276
277 pr->phys_id = acpi_get_phys_id(pr->handle, device_declaration,
278 pr->acpi_id);
279 if (invalid_phys_cpuid(pr->phys_id))
280 dev_dbg(&device->dev, "Failed to get CPU physical ID.\n");
281
282 pr->id = acpi_map_cpuid(pr->phys_id, pr->acpi_id);
283 if (!cpu0_initialized && !acpi_has_cpu_in_madt()) {
284 cpu0_initialized = 1;
285 /*
286 * Handle UP system running SMP kernel, with no CPU
287 * entry in MADT
288 */
289 if (invalid_logical_cpuid(pr->id) && (num_online_cpus() == 1))
290 pr->id = 0;
291 }
292
293 /*
294 * Extra Processor objects may be enumerated on MP systems with
295 * less than the max # of CPUs. They should be ignored _iff
296 * they are physically not present.
297 *
298 * NOTE: Even if the processor has a cpuid, it may not be present
299 * because cpuid <-> apicid mapping is persistent now.
300 */
301 if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id)) {
302 int ret = acpi_processor_hotadd_init(pr);
303
304 if (ret)
305 return ret;
306 }
307
308 /*
309 * On some boxes several processors use the same processor bus id.
310 * But they are located in different scope. For example:
311 * \_SB.SCK0.CPU0
312 * \_SB.SCK1.CPU0
313 * Rename the processor device bus id. And the new bus id will be
314 * generated as the following format:
315 * CPU+CPU ID.
316 */
317 sprintf(acpi_device_bid(device), "CPU%X", pr->id);
318 dev_dbg(&device->dev, "Processor [%d:%d]\n", pr->id, pr->acpi_id);
319
320 if (!object.processor.pblk_address)
321 dev_dbg(&device->dev, "No PBLK (NULL address)\n");
322 else if (object.processor.pblk_length != 6)
323 dev_err(&device->dev, "Invalid PBLK length [%d]\n",
324 object.processor.pblk_length);
325 else {
326 pr->throttling.address = object.processor.pblk_address;
327 pr->throttling.duty_offset = acpi_gbl_FADT.duty_offset;
328 pr->throttling.duty_width = acpi_gbl_FADT.duty_width;
329
330 pr->pblk = object.processor.pblk_address;
331 }
332
333 /*
334 * If ACPI describes a slot number for this CPU, we can use it to
335 * ensure we get the right value in the "physical id" field
336 * of /proc/cpuinfo
337 */
338 status = acpi_evaluate_integer(pr->handle, "_SUN", NULL, &value);
339 if (ACPI_SUCCESS(status))
340 arch_fix_phys_package_id(pr->id, value);
341
342 return 0;
343}
344
345/*
346 * Do not put anything in here which needs the core to be online.
347 * For example MSR access or setting up things which check for cpuinfo_x86
348 * (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
349 * Such things have to be put in and set up by the processor driver's .probe().
350 */
351static DEFINE_PER_CPU(void *, processor_device_array);
352
353static int acpi_processor_add(struct acpi_device *device,
354 const struct acpi_device_id *id)
355{
356 struct acpi_processor *pr;
357 struct device *dev;
358 int result = 0;
359
360 pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
361 if (!pr)
362 return -ENOMEM;
363
364 if (!zalloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
365 result = -ENOMEM;
366 goto err_free_pr;
367 }
368
369 pr->handle = device->handle;
370 strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
371 strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
372 device->driver_data = pr;
373
374 result = acpi_processor_get_info(device);
375 if (result) /* Processor is not physically present or unavailable */
376 return 0;
377
378 BUG_ON(pr->id >= nr_cpu_ids);
379
380 /*
381 * Buggy BIOS check.
382 * ACPI id of processors can be reported wrongly by the BIOS.
383 * Don't trust it blindly
384 */
385 if (per_cpu(processor_device_array, pr->id) != NULL &&
386 per_cpu(processor_device_array, pr->id) != device) {
387 dev_warn(&device->dev,
388 "BIOS reported wrong ACPI id %d for the processor\n",
389 pr->id);
390 /* Give up, but do not abort the namespace scan. */
391 goto err;
392 }
393 /*
394 * processor_device_array is not cleared on errors to allow buggy BIOS
395 * checks.
396 */
397 per_cpu(processor_device_array, pr->id) = device;
398 per_cpu(processors, pr->id) = pr;
399
400 dev = get_cpu_device(pr->id);
401 if (!dev) {
402 result = -ENODEV;
403 goto err;
404 }
405
406 result = acpi_bind_one(dev, device);
407 if (result)
408 goto err;
409
410 pr->dev = dev;
411
412 /* Trigger the processor driver's .probe() if present. */
413 if (device_attach(dev) >= 0)
414 return 1;
415
416 dev_err(dev, "Processor driver could not be attached\n");
417 acpi_unbind_one(dev);
418
419 err:
420 free_cpumask_var(pr->throttling.shared_cpu_map);
421 device->driver_data = NULL;
422 per_cpu(processors, pr->id) = NULL;
423 err_free_pr:
424 kfree(pr);
425 return result;
426}
427
428#ifdef CONFIG_ACPI_HOTPLUG_CPU
429/* Removal */
430static void acpi_processor_remove(struct acpi_device *device)
431{
432 struct acpi_processor *pr;
433
434 if (!device || !acpi_driver_data(device))
435 return;
436
437 pr = acpi_driver_data(device);
438 if (pr->id >= nr_cpu_ids)
439 goto out;
440
441 /*
442 * The only reason why we ever get here is CPU hot-removal. The CPU is
443 * already offline and the ACPI device removal locking prevents it from
444 * being put back online at this point.
445 *
446 * Unbind the driver from the processor device and detach it from the
447 * ACPI companion object.
448 */
449 device_release_driver(pr->dev);
450 acpi_unbind_one(pr->dev);
451
452 /* Clean up. */
453 per_cpu(processor_device_array, pr->id) = NULL;
454 per_cpu(processors, pr->id) = NULL;
455
456 cpu_maps_update_begin();
457 cpu_hotplug_begin();
458
459 /* Remove the CPU. */
460 arch_unregister_cpu(pr->id);
461 acpi_unmap_cpu(pr->id);
462
463 cpu_hotplug_done();
464 cpu_maps_update_done();
465
466 try_offline_node(cpu_to_node(pr->id));
467
468 out:
469 free_cpumask_var(pr->throttling.shared_cpu_map);
470 kfree(pr);
471}
472#endif /* CONFIG_ACPI_HOTPLUG_CPU */
473
474#ifdef CONFIG_X86
475static bool acpi_hwp_native_thermal_lvt_set;
476static acpi_status __init acpi_hwp_native_thermal_lvt_osc(acpi_handle handle,
477 u32 lvl,
478 void *context,
479 void **rv)
480{
481 u8 sb_uuid_str[] = "4077A616-290C-47BE-9EBD-D87058713953";
482 u32 capbuf[2];
483 struct acpi_osc_context osc_context = {
484 .uuid_str = sb_uuid_str,
485 .rev = 1,
486 .cap.length = 8,
487 .cap.pointer = capbuf,
488 };
489
490 if (acpi_hwp_native_thermal_lvt_set)
491 return AE_CTRL_TERMINATE;
492
493 capbuf[0] = 0x0000;
494 capbuf[1] = 0x1000; /* set bit 12 */
495
496 if (ACPI_SUCCESS(acpi_run_osc(handle, &osc_context))) {
497 if (osc_context.ret.pointer && osc_context.ret.length > 1) {
498 u32 *capbuf_ret = osc_context.ret.pointer;
499
500 if (capbuf_ret[1] & 0x1000) {
501 acpi_handle_info(handle,
502 "_OSC native thermal LVT Acked\n");
503 acpi_hwp_native_thermal_lvt_set = true;
504 }
505 }
506 kfree(osc_context.ret.pointer);
507 }
508
509 return AE_OK;
510}
511
512void __init acpi_early_processor_osc(void)
513{
514 if (boot_cpu_has(X86_FEATURE_HWP)) {
515 acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
516 ACPI_UINT32_MAX,
517 acpi_hwp_native_thermal_lvt_osc,
518 NULL, NULL, NULL);
519 acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID,
520 acpi_hwp_native_thermal_lvt_osc,
521 NULL, NULL);
522 }
523}
524#endif
525
526/*
527 * The following ACPI IDs are known to be suitable for representing as
528 * processor devices.
529 */
530static const struct acpi_device_id processor_device_ids[] = {
531
532 { ACPI_PROCESSOR_OBJECT_HID, },
533 { ACPI_PROCESSOR_DEVICE_HID, },
534
535 { }
536};
537
538static struct acpi_scan_handler processor_handler = {
539 .ids = processor_device_ids,
540 .attach = acpi_processor_add,
541#ifdef CONFIG_ACPI_HOTPLUG_CPU
542 .detach = acpi_processor_remove,
543#endif
544 .hotplug = {
545 .enabled = true,
546 },
547};
548
549static int acpi_processor_container_attach(struct acpi_device *dev,
550 const struct acpi_device_id *id)
551{
552 return 1;
553}
554
555static const struct acpi_device_id processor_container_ids[] = {
556 { ACPI_PROCESSOR_CONTAINER_HID, },
557 { }
558};
559
560static struct acpi_scan_handler processor_container_handler = {
561 .ids = processor_container_ids,
562 .attach = acpi_processor_container_attach,
563};
564
565/* The number of the unique processor IDs */
566static int nr_unique_ids __initdata;
567
568/* The number of the duplicate processor IDs */
569static int nr_duplicate_ids;
570
571/* Used to store the unique processor IDs */
572static int unique_processor_ids[] __initdata = {
573 [0 ... NR_CPUS - 1] = -1,
574};
575
576/* Used to store the duplicate processor IDs */
577static int duplicate_processor_ids[] = {
578 [0 ... NR_CPUS - 1] = -1,
579};
580
581static void __init processor_validated_ids_update(int proc_id)
582{
583 int i;
584
585 if (nr_unique_ids == NR_CPUS||nr_duplicate_ids == NR_CPUS)
586 return;
587
588 /*
589 * Firstly, compare the proc_id with duplicate IDs, if the proc_id is
590 * already in the IDs, do nothing.
591 */
592 for (i = 0; i < nr_duplicate_ids; i++) {
593 if (duplicate_processor_ids[i] == proc_id)
594 return;
595 }
596
597 /*
598 * Secondly, compare the proc_id with unique IDs, if the proc_id is in
599 * the IDs, put it in the duplicate IDs.
600 */
601 for (i = 0; i < nr_unique_ids; i++) {
602 if (unique_processor_ids[i] == proc_id) {
603 duplicate_processor_ids[nr_duplicate_ids] = proc_id;
604 nr_duplicate_ids++;
605 return;
606 }
607 }
608
609 /*
610 * Lastly, the proc_id is a unique ID, put it in the unique IDs.
611 */
612 unique_processor_ids[nr_unique_ids] = proc_id;
613 nr_unique_ids++;
614}
615
616static acpi_status __init acpi_processor_ids_walk(acpi_handle handle,
617 u32 lvl,
618 void *context,
619 void **rv)
620{
621 acpi_status status;
622 acpi_object_type acpi_type;
623 unsigned long long uid;
624 union acpi_object object = { 0 };
625 struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
626
627 status = acpi_get_type(handle, &acpi_type);
628 if (ACPI_FAILURE(status))
629 return status;
630
631 switch (acpi_type) {
632 case ACPI_TYPE_PROCESSOR:
633 status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
634 if (ACPI_FAILURE(status))
635 goto err;
636 uid = object.processor.proc_id;
637 break;
638
639 case ACPI_TYPE_DEVICE:
640 status = acpi_evaluate_integer(handle, "_UID", NULL, &uid);
641 if (ACPI_FAILURE(status))
642 goto err;
643 break;
644 default:
645 goto err;
646 }
647
648 processor_validated_ids_update(uid);
649 return AE_OK;
650
651err:
652 /* Exit on error, but don't abort the namespace walk */
653 acpi_handle_info(handle, "Invalid processor object\n");
654 return AE_OK;
655
656}
657
658static void __init acpi_processor_check_duplicates(void)
659{
660 /* check the correctness for all processors in ACPI namespace */
661 acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
662 ACPI_UINT32_MAX,
663 acpi_processor_ids_walk,
664 NULL, NULL, NULL);
665 acpi_get_devices(ACPI_PROCESSOR_DEVICE_HID, acpi_processor_ids_walk,
666 NULL, NULL);
667}
668
669bool acpi_duplicate_processor_id(int proc_id)
670{
671 int i;
672
673 /*
674 * compare the proc_id with duplicate IDs, if the proc_id is already
675 * in the duplicate IDs, return true, otherwise, return false.
676 */
677 for (i = 0; i < nr_duplicate_ids; i++) {
678 if (duplicate_processor_ids[i] == proc_id)
679 return true;
680 }
681 return false;
682}
683
684void __init acpi_processor_init(void)
685{
686 acpi_processor_check_duplicates();
687 acpi_scan_add_handler_with_hotplug(&processor_handler, "processor");
688 acpi_scan_add_handler(&processor_container_handler);
689}
690
691#ifdef CONFIG_ACPI_PROCESSOR_CSTATE
692/**
693 * acpi_processor_claim_cst_control - Request _CST control from the platform.
694 */
695bool acpi_processor_claim_cst_control(void)
696{
697 static bool cst_control_claimed;
698 acpi_status status;
699
700 if (!acpi_gbl_FADT.cst_control || cst_control_claimed)
701 return true;
702
703 status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
704 acpi_gbl_FADT.cst_control, 8);
705 if (ACPI_FAILURE(status)) {
706 pr_warn("ACPI: Failed to claim processor _CST control\n");
707 return false;
708 }
709
710 cst_control_claimed = true;
711 return true;
712}
713EXPORT_SYMBOL_GPL(acpi_processor_claim_cst_control);
714
715/**
716 * acpi_processor_evaluate_cst - Evaluate the processor _CST control method.
717 * @handle: ACPI handle of the processor object containing the _CST.
718 * @cpu: The numeric ID of the target CPU.
719 * @info: Object write the C-states information into.
720 *
721 * Extract the C-state information for the given CPU from the output of the _CST
722 * control method under the corresponding ACPI processor object (or processor
723 * device object) and populate @info with it.
724 *
725 * If any ACPI_ADR_SPACE_FIXED_HARDWARE C-states are found, invoke
726 * acpi_processor_ffh_cstate_probe() to verify them and update the
727 * cpu_cstate_entry data for @cpu.
728 */
729int acpi_processor_evaluate_cst(acpi_handle handle, u32 cpu,
730 struct acpi_processor_power *info)
731{
732 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
733 union acpi_object *cst;
734 acpi_status status;
735 u64 count;
736 int last_index = 0;
737 int i, ret = 0;
738
739 status = acpi_evaluate_object(handle, "_CST", NULL, &buffer);
740 if (ACPI_FAILURE(status)) {
741 acpi_handle_debug(handle, "No _CST\n");
742 return -ENODEV;
743 }
744
745 cst = buffer.pointer;
746
747 /* There must be at least 2 elements. */
748 if (!cst || cst->type != ACPI_TYPE_PACKAGE || cst->package.count < 2) {
749 acpi_handle_warn(handle, "Invalid _CST output\n");
750 ret = -EFAULT;
751 goto end;
752 }
753
754 count = cst->package.elements[0].integer.value;
755
756 /* Validate the number of C-states. */
757 if (count < 1 || count != cst->package.count - 1) {
758 acpi_handle_warn(handle, "Inconsistent _CST data\n");
759 ret = -EFAULT;
760 goto end;
761 }
762
763 for (i = 1; i <= count; i++) {
764 union acpi_object *element;
765 union acpi_object *obj;
766 struct acpi_power_register *reg;
767 struct acpi_processor_cx cx;
768
769 /*
770 * If there is not enough space for all C-states, skip the
771 * excess ones and log a warning.
772 */
773 if (last_index >= ACPI_PROCESSOR_MAX_POWER - 1) {
774 acpi_handle_warn(handle,
775 "No room for more idle states (limit: %d)\n",
776 ACPI_PROCESSOR_MAX_POWER - 1);
777 break;
778 }
779
780 memset(&cx, 0, sizeof(cx));
781
782 element = &cst->package.elements[i];
783 if (element->type != ACPI_TYPE_PACKAGE) {
784 acpi_handle_info(handle, "_CST C%d type(%x) is not package, skip...\n",
785 i, element->type);
786 continue;
787 }
788
789 if (element->package.count != 4) {
790 acpi_handle_info(handle, "_CST C%d package count(%d) is not 4, skip...\n",
791 i, element->package.count);
792 continue;
793 }
794
795 obj = &element->package.elements[0];
796
797 if (obj->type != ACPI_TYPE_BUFFER) {
798 acpi_handle_info(handle, "_CST C%d package element[0] type(%x) is not buffer, skip...\n",
799 i, obj->type);
800 continue;
801 }
802
803 reg = (struct acpi_power_register *)obj->buffer.pointer;
804
805 obj = &element->package.elements[1];
806 if (obj->type != ACPI_TYPE_INTEGER) {
807 acpi_handle_info(handle, "_CST C[%d] package element[1] type(%x) is not integer, skip...\n",
808 i, obj->type);
809 continue;
810 }
811
812 cx.type = obj->integer.value;
813 /*
814 * There are known cases in which the _CST output does not
815 * contain C1, so if the type of the first state found is not
816 * C1, leave an empty slot for C1 to be filled in later.
817 */
818 if (i == 1 && cx.type != ACPI_STATE_C1)
819 last_index = 1;
820
821 cx.address = reg->address;
822 cx.index = last_index + 1;
823
824 if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
825 if (!acpi_processor_ffh_cstate_probe(cpu, &cx, reg)) {
826 /*
827 * In the majority of cases _CST describes C1 as
828 * a FIXED_HARDWARE C-state, but if the command
829 * line forbids using MWAIT, use CSTATE_HALT for
830 * C1 regardless.
831 */
832 if (cx.type == ACPI_STATE_C1 &&
833 boot_option_idle_override == IDLE_NOMWAIT) {
834 cx.entry_method = ACPI_CSTATE_HALT;
835 snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
836 } else {
837 cx.entry_method = ACPI_CSTATE_FFH;
838 }
839 } else if (cx.type == ACPI_STATE_C1) {
840 /*
841 * In the special case of C1, FIXED_HARDWARE can
842 * be handled by executing the HLT instruction.
843 */
844 cx.entry_method = ACPI_CSTATE_HALT;
845 snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
846 } else {
847 acpi_handle_info(handle, "_CST C%d declares FIXED_HARDWARE C-state but not supported in hardware, skip...\n",
848 i);
849 continue;
850 }
851 } else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
852 cx.entry_method = ACPI_CSTATE_SYSTEMIO;
853 snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
854 cx.address);
855 } else {
856 acpi_handle_info(handle, "_CST C%d space_id(%x) neither FIXED_HARDWARE nor SYSTEM_IO, skip...\n",
857 i, reg->space_id);
858 continue;
859 }
860
861 if (cx.type == ACPI_STATE_C1)
862 cx.valid = 1;
863
864 obj = &element->package.elements[2];
865 if (obj->type != ACPI_TYPE_INTEGER) {
866 acpi_handle_info(handle, "_CST C%d package element[2] type(%x) not integer, skip...\n",
867 i, obj->type);
868 continue;
869 }
870
871 cx.latency = obj->integer.value;
872
873 obj = &element->package.elements[3];
874 if (obj->type != ACPI_TYPE_INTEGER) {
875 acpi_handle_info(handle, "_CST C%d package element[3] type(%x) not integer, skip...\n",
876 i, obj->type);
877 continue;
878 }
879
880 memcpy(&info->states[++last_index], &cx, sizeof(cx));
881 }
882
883 acpi_handle_info(handle, "Found %d idle states\n", last_index);
884
885 info->count = last_index;
886
887end:
888 kfree(buffer.pointer);
889
890 return ret;
891}
892EXPORT_SYMBOL_GPL(acpi_processor_evaluate_cst);
893#endif /* CONFIG_ACPI_PROCESSOR_CSTATE */