fan_core.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *  fan_core.c - ACPI Fan core Driver
  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) 2022 Intel Corporation. All rights reserved.
  8 */
  9
 10#include <linux/bits.h>
 11#include <linux/kernel.h>
 12#include <linux/limits.h>
 13#include <linux/math.h>
 14#include <linux/math64.h>
 15#include <linux/module.h>
 16#include <linux/init.h>
 17#include <linux/types.h>
 18#include <linux/uaccess.h>
 19#include <linux/uuid.h>
 20#include <linux/thermal.h>
 21#include <linux/acpi.h>
 22#include <linux/platform_device.h>
 23#include <linux/sort.h>
 24
 25#include "fan.h"
 26
 27#define ACPI_FAN_NOTIFY_STATE_CHANGED	0x80
 28
 29/*
 30 * Defined inside the "Fan Noise Signal" section at
 31 * https://learn.microsoft.com/en-us/windows-hardware/design/device-experiences/design-guide.
 32 */
 33static const guid_t acpi_fan_microsoft_guid = GUID_INIT(0xA7611840, 0x99FE, 0x41AE, 0xA4, 0x88,
 34							0x35, 0xC7, 0x59, 0x26, 0xC8, 0xEB);
 35#define ACPI_FAN_DSM_GET_TRIP_POINT_GRANULARITY 1
 36#define ACPI_FAN_DSM_SET_TRIP_POINTS		2
 37#define ACPI_FAN_DSM_GET_OPERATING_RANGES	3
 38
 39/*
 40 * Ensures that fans with a very low trip point granularity
 41 * do not send too many notifications.
 42 */
 43static uint min_trip_distance = 100;
 44module_param(min_trip_distance, uint, 0);
 45MODULE_PARM_DESC(min_trip_distance, "Minimum distance between fan speed trip points in RPM");
 46
 47static const struct acpi_device_id fan_device_ids[] = {
 48	ACPI_FAN_DEVICE_IDS,
 49	{"", 0},
 50};
 51MODULE_DEVICE_TABLE(acpi, fan_device_ids);
 52
 53/* thermal cooling device callbacks */
 54static int fan_get_max_state(struct thermal_cooling_device *cdev, unsigned long
 55			     *state)
 56{
 57	struct acpi_device *device = cdev->devdata;
 58	struct acpi_fan *fan = acpi_driver_data(device);
 59
 60	if (fan->acpi4) {
 61		if (fan->fif.fine_grain_ctrl)
 62			*state = 100 / fan->fif.step_size;
 63		else
 64			*state = fan->fps_count - 1;
 65	} else {
 66		*state = 1;
 67	}
 68
 69	return 0;
 70}
 71
 72int acpi_fan_get_fst(acpi_handle handle, struct acpi_fan_fst *fst)
 73{
 74	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 75	union acpi_object *obj;
 76	acpi_status status;
 77	int ret = 0;
 78
 79	status = acpi_evaluate_object(handle, "_FST", NULL, &buffer);
 80	if (ACPI_FAILURE(status))
 81		return -EIO;
 82
 83	obj = buffer.pointer;
 84	if (!obj)
 85		return -ENODATA;
 86
 87	if (obj->type != ACPI_TYPE_PACKAGE || obj->package.count != 3) {
 88		ret = -EPROTO;
 89		goto err;
 90	}
 91
 92	if (obj->package.elements[0].type != ACPI_TYPE_INTEGER ||
 93	    obj->package.elements[1].type != ACPI_TYPE_INTEGER ||
 94	    obj->package.elements[2].type != ACPI_TYPE_INTEGER) {
 95		ret = -EPROTO;
 96		goto err;
 97	}
 98
 99	fst->revision = obj->package.elements[0].integer.value;
100	fst->control = obj->package.elements[1].integer.value;
101	fst->speed = obj->package.elements[2].integer.value;
102
103err:
104	kfree(obj);
105	return ret;
106}
107
108static int fan_get_state_acpi4(struct acpi_device *device, unsigned long *state)
109{
110	struct acpi_fan *fan = acpi_driver_data(device);
111	struct acpi_fan_fst fst;
112	int status, i;
113
114	status = acpi_fan_get_fst(device->handle, &fst);
115	if (status)
116		return status;
117
118	if (fan->fif.fine_grain_ctrl) {
119		/* This control should be same what we set using _FSL by spec */
120		if (fst.control > 100) {
121			dev_dbg(&device->dev, "Invalid control value returned\n");
122			goto match_fps;
123		}
124
125		*state = (int) fst.control / fan->fif.step_size;
126		return 0;
127	}
128
129match_fps:
130	for (i = 0; i < fan->fps_count; i++) {
131		if (fst.control == fan->fps[i].control)
132			break;
133	}
134	if (i == fan->fps_count) {
135		dev_dbg(&device->dev, "No matching fps control value\n");
136		return -EINVAL;
137	}
138
139	*state = i;
140
141	return status;
142}
143
144static int fan_get_state(struct acpi_device *device, unsigned long *state)
145{
146	int result;
147	int acpi_state = ACPI_STATE_D0;
148
149	result = acpi_device_update_power(device, &acpi_state);
150	if (result)
151		return result;
152
153	*state = acpi_state == ACPI_STATE_D3_COLD
154			|| acpi_state == ACPI_STATE_D3_HOT ?
155		0 : (acpi_state == ACPI_STATE_D0 ? 1 : -1);
156	return 0;
157}
158
159static int fan_get_cur_state(struct thermal_cooling_device *cdev, unsigned long
160			     *state)
161{
162	struct acpi_device *device = cdev->devdata;
163	struct acpi_fan *fan = acpi_driver_data(device);
164
165	if (fan->acpi4)
166		return fan_get_state_acpi4(device, state);
167	else
168		return fan_get_state(device, state);
169}
170
171static int fan_set_state(struct acpi_device *device, unsigned long state)
172{
173	if (state != 0 && state != 1)
174		return -EINVAL;
175
176	return acpi_device_set_power(device,
177				     state ? ACPI_STATE_D0 : ACPI_STATE_D3_COLD);
178}
179
180static int fan_set_state_acpi4(struct acpi_device *device, unsigned long state)
181{
182	struct acpi_fan *fan = acpi_driver_data(device);
183	acpi_status status;
184	u64 value = state;
185	int max_state;
186
187	if (fan->fif.fine_grain_ctrl)
188		max_state = 100 / fan->fif.step_size;
189	else
190		max_state = fan->fps_count - 1;
191
192	if (state > max_state)
193		return -EINVAL;
194
195	if (fan->fif.fine_grain_ctrl) {
196		value *= fan->fif.step_size;
197		/* Spec allows compensate the last step only */
198		if (value + fan->fif.step_size > 100)
199			value = 100;
200	} else {
201		value = fan->fps[state].control;
202	}
203
204	status = acpi_execute_simple_method(device->handle, "_FSL", value);
205	if (ACPI_FAILURE(status)) {
206		dev_dbg(&device->dev, "Failed to set state by _FSL\n");
207		return -ENODEV;
208	}
209
210	return 0;
211}
212
213static int
214fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
215{
216	struct acpi_device *device = cdev->devdata;
217	struct acpi_fan *fan = acpi_driver_data(device);
218
219	if (fan->acpi4)
220		return fan_set_state_acpi4(device, state);
221	else
222		return fan_set_state(device, state);
223}
224
225static const struct thermal_cooling_device_ops fan_cooling_ops = {
226	.get_max_state = fan_get_max_state,
227	.get_cur_state = fan_get_cur_state,
228	.set_cur_state = fan_set_cur_state,
229};
230
231/* --------------------------------------------------------------------------
232 *                               Driver Interface
233 * --------------------------------------------------------------------------
234*/
235
236static int acpi_fan_get_fif(struct acpi_device *device)
237{
238	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
239	struct acpi_fan *fan = acpi_driver_data(device);
240	struct acpi_buffer format = { sizeof("NNNN"), "NNNN" };
241	u64 fields[4];
242	struct acpi_buffer fif = { sizeof(fields), fields };
243	union acpi_object *obj;
244	acpi_status status;
245
246	status = acpi_evaluate_object(device->handle, "_FIF", NULL, &buffer);
247	if (ACPI_FAILURE(status))
248		return status;
249
250	obj = buffer.pointer;
251	if (!obj || obj->type != ACPI_TYPE_PACKAGE) {
252		dev_err(&device->dev, "Invalid _FIF data\n");
253		status = -EINVAL;
254		goto err;
255	}
256
257	status = acpi_extract_package(obj, &format, &fif);
258	if (ACPI_FAILURE(status)) {
259		dev_err(&device->dev, "Invalid _FIF element\n");
260		status = -EINVAL;
261		goto err;
262	}
263
264	fan->fif.revision = fields[0];
265	fan->fif.fine_grain_ctrl = fields[1];
266	fan->fif.step_size = fields[2];
267	fan->fif.low_speed_notification = fields[3];
268
269	/* If there is a bug in step size and set as 0, change to 1 */
270	if (!fan->fif.step_size)
271		fan->fif.step_size = 1;
272	/* If step size > 9, change to 9 (by spec valid values 1-9) */
273	else if (fan->fif.step_size > 9)
274		fan->fif.step_size = 9;
275err:
276	kfree(obj);
277	return status;
278}
279
280static int acpi_fan_speed_cmp(const void *a, const void *b)
281{
282	const struct acpi_fan_fps *fps1 = a;
283	const struct acpi_fan_fps *fps2 = b;
284	return fps1->speed - fps2->speed;
285}
286
287static int acpi_fan_get_fps(struct acpi_device *device)
288{
289	struct acpi_fan *fan = acpi_driver_data(device);
290	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
291	union acpi_object *obj;
292	acpi_status status;
293	int i;
294
295	status = acpi_evaluate_object(device->handle, "_FPS", NULL, &buffer);
296	if (ACPI_FAILURE(status))
297		return status;
298
299	obj = buffer.pointer;
300	if (!obj || obj->type != ACPI_TYPE_PACKAGE || obj->package.count < 2) {
301		dev_err(&device->dev, "Invalid _FPS data\n");
302		status = -EINVAL;
303		goto err;
304	}
305
306	fan->fps_count = obj->package.count - 1; /* minus revision field */
307	fan->fps = devm_kcalloc(&device->dev,
308				fan->fps_count, sizeof(struct acpi_fan_fps),
309				GFP_KERNEL);
310	if (!fan->fps) {
311		dev_err(&device->dev, "Not enough memory\n");
312		status = -ENOMEM;
313		goto err;
314	}
315	for (i = 0; i < fan->fps_count; i++) {
316		struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
317		struct acpi_buffer fps = { offsetof(struct acpi_fan_fps, name),
318						&fan->fps[i] };
319		status = acpi_extract_package(&obj->package.elements[i + 1],
320					      &format, &fps);
321		if (ACPI_FAILURE(status)) {
322			dev_err(&device->dev, "Invalid _FPS element\n");
323			goto err;
324		}
325	}
326
327	/* sort the state array according to fan speed in increase order */
328	sort(fan->fps, fan->fps_count, sizeof(*fan->fps),
329	     acpi_fan_speed_cmp, NULL);
330
331err:
332	kfree(obj);
333	return status;
334}
335
336static int acpi_fan_dsm_init(struct device *dev)
337{
338	union acpi_object dummy = {
339		.package = {
340			.type = ACPI_TYPE_PACKAGE,
341			.count = 0,
342			.elements = NULL,
343		},
344	};
345	struct acpi_fan *fan = dev_get_drvdata(dev);
346	union acpi_object *obj;
347	int ret = 0;
348
349	if (!acpi_check_dsm(fan->handle, &acpi_fan_microsoft_guid, 0,
350			    BIT(ACPI_FAN_DSM_GET_TRIP_POINT_GRANULARITY) |
351			    BIT(ACPI_FAN_DSM_SET_TRIP_POINTS)))
352		return 0;
353
354	dev_info(dev, "Using Microsoft fan extensions\n");
355
356	obj = acpi_evaluate_dsm_typed(fan->handle, &acpi_fan_microsoft_guid, 0,
357				      ACPI_FAN_DSM_GET_TRIP_POINT_GRANULARITY, &dummy,
358				      ACPI_TYPE_INTEGER);
359	if (!obj)
360		return -EIO;
361
362	if (obj->integer.value > U32_MAX)
363		ret = -EOVERFLOW;
364	else
365		fan->fan_trip_granularity = obj->integer.value;
366
367	kfree(obj);
368
369	return ret;
370}
371
372static int acpi_fan_dsm_set_trip_points(struct device *dev, u64 upper, u64 lower)
373{
374	union acpi_object args[2] = {
375		{
376			.integer = {
377				.type = ACPI_TYPE_INTEGER,
378				.value = lower,
379			},
380		},
381		{
382			.integer = {
383				.type = ACPI_TYPE_INTEGER,
384				.value = upper,
385			},
386		},
387	};
388	struct acpi_fan *fan = dev_get_drvdata(dev);
389	union acpi_object in = {
390		.package = {
391			.type = ACPI_TYPE_PACKAGE,
392			.count = ARRAY_SIZE(args),
393			.elements = args,
394		},
395	};
396	union acpi_object *obj;
397
398	obj = acpi_evaluate_dsm(fan->handle, &acpi_fan_microsoft_guid, 0,
399				ACPI_FAN_DSM_SET_TRIP_POINTS, &in);
400	kfree(obj);
401
402	return 0;
403}
404
405static int acpi_fan_dsm_start(struct device *dev)
406{
407	struct acpi_fan *fan = dev_get_drvdata(dev);
408	int ret;
409
410	if (!fan->fan_trip_granularity)
411		return 0;
412
413	/*
414	 * Some firmware implementations only update the values returned by the
415	 * _FST control method when a notification is received. This usually
416	 * works with Microsoft Windows as setting up trip points will keep
417	 * triggering said notifications, but will cause issues when using _FST
418	 * without the Microsoft-specific trip point extension.
419	 *
420	 * Because of this, an initial notification needs to be triggered to
421	 * start the cycle of trip points updates. This is achieved by setting
422	 * the trip points sequencially to two separate ranges. As by the
423	 * Microsoft specification the firmware should trigger a notification
424	 * immediately if the fan speed is outside the trip point range. This
425	 * _should_ result in at least one notification as both ranges do not
426	 * overlap, meaning that the current fan speed needs to be outside at
427	 * least one range.
428	 */
429	ret = acpi_fan_dsm_set_trip_points(dev, fan->fan_trip_granularity, 0);
430	if (ret < 0)
431		return ret;
432
433	return acpi_fan_dsm_set_trip_points(dev, fan->fan_trip_granularity * 3,
434					    fan->fan_trip_granularity * 2);
435}
436
437static int acpi_fan_dsm_update_trips_points(struct device *dev, struct acpi_fan_fst *fst)
438{
439	struct acpi_fan *fan = dev_get_drvdata(dev);
440	u64 upper, lower;
441
442	if (!fan->fan_trip_granularity)
443		return 0;
444
445	if (!acpi_fan_speed_valid(fst->speed))
446		return -EINVAL;
447
448	upper = roundup_u64(fst->speed + min_trip_distance, fan->fan_trip_granularity);
449	if (fst->speed <= min_trip_distance) {
450		lower = 0;
451	} else {
452		/*
453		 * Valid fan speed values cannot be larger than 32 bit, so
454		 * we can safely assume that no overflow will happen here.
455		 */
456		lower = rounddown((u32)fst->speed - min_trip_distance, fan->fan_trip_granularity);
457	}
458
459	return acpi_fan_dsm_set_trip_points(dev, upper, lower);
460}
461
462static void acpi_fan_notify_handler(acpi_handle handle, u32 event, void *context)
463{
464	struct device *dev = context;
465	struct acpi_fan_fst fst;
466	int ret;
467
468	switch (event) {
469	case ACPI_FAN_NOTIFY_STATE_CHANGED:
470		/*
471		 * The ACPI specification says that we must evaluate _FST when we
472		 * receive an ACPI event indicating that the fan state has changed.
473		 */
474		ret = acpi_fan_get_fst(handle, &fst);
475		if (ret < 0) {
476			dev_err(dev, "Error retrieving current fan status: %d\n", ret);
477		} else {
478			ret = acpi_fan_dsm_update_trips_points(dev, &fst);
479			if (ret < 0)
480				dev_err(dev, "Failed to update trip points: %d\n", ret);
481		}
482
483		acpi_fan_notify_hwmon(dev);
484		acpi_bus_generate_netlink_event("fan", dev_name(dev), event, 0);
485		break;
486	default:
487		dev_dbg(dev, "Unsupported ACPI notification 0x%x\n", event);
488		break;
489	}
490}
491
492static void acpi_fan_notify_remove(void *data)
493{
494	struct acpi_fan *fan = data;
495
496	acpi_remove_notify_handler(fan->handle, ACPI_DEVICE_NOTIFY, acpi_fan_notify_handler);
497}
498
499static int devm_acpi_fan_notify_init(struct device *dev)
500{
501	struct acpi_fan *fan = dev_get_drvdata(dev);
502	acpi_status status;
503
504	status = acpi_install_notify_handler(fan->handle, ACPI_DEVICE_NOTIFY,
505					     acpi_fan_notify_handler, dev);
506	if (ACPI_FAILURE(status))
507		return -EIO;
508
509	return devm_add_action_or_reset(dev, acpi_fan_notify_remove, fan);
510}
511
512static int acpi_fan_probe(struct platform_device *pdev)
513{
514	int result = 0;
515	struct thermal_cooling_device *cdev;
516	struct acpi_fan *fan;
517	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
518	char *name;
519
520	if (!device)
521		return -ENODEV;
522
523	fan = devm_kzalloc(&pdev->dev, sizeof(*fan), GFP_KERNEL);
524	if (!fan) {
525		dev_err(&device->dev, "No memory for fan\n");
526		return -ENOMEM;
527	}
528
529	fan->handle = device->handle;
530	device->driver_data = fan;
531	platform_set_drvdata(pdev, fan);
532
533	if (acpi_has_method(device->handle, "_FST")) {
534		fan->has_fst = true;
535		fan->acpi4 = acpi_has_method(device->handle, "_FIF") &&
536				acpi_has_method(device->handle, "_FPS") &&
537				acpi_has_method(device->handle, "_FSL");
538	}
539
540	if (fan->acpi4) {
541		result = acpi_fan_get_fif(device);
542		if (result)
543			return result;
544
545		result = acpi_fan_get_fps(device);
546		if (result)
547			return result;
548	}
549
550	if (fan->has_fst) {
551		result = acpi_fan_dsm_init(&pdev->dev);
552		if (result)
553			return result;
554
555		result = devm_acpi_fan_create_hwmon(&pdev->dev);
556		if (result)
557			return result;
558
559		result = devm_acpi_fan_notify_init(&pdev->dev);
560		if (result)
561			return result;
562
563		result = acpi_fan_dsm_start(&pdev->dev);
564		if (result) {
565			dev_err(&pdev->dev, "Failed to start Microsoft fan extensions\n");
566			return result;
567		}
568
569		result = acpi_fan_create_attributes(device);
570		if (result)
571			return result;
572	}
573
574	if (!fan->acpi4) {
575		result = acpi_device_update_power(device, NULL);
576		if (result) {
577			dev_err(&device->dev, "Failed to set initial power state\n");
578			goto err_end;
579		}
580	}
581
582	if (!strncmp(pdev->name, "PNP0C0B", strlen("PNP0C0B")))
583		name = "Fan";
584	else
585		name = acpi_device_bid(device);
586
587	cdev = thermal_cooling_device_register(name, device,
588						&fan_cooling_ops);
589	if (IS_ERR(cdev)) {
590		result = PTR_ERR(cdev);
591		goto err_end;
592	}
593
594	dev_dbg(&pdev->dev, "registered as cooling_device%d\n", cdev->id);
595
596	fan->cdev = cdev;
597	result = sysfs_create_link(&pdev->dev.kobj,
598				   &cdev->device.kobj,
599				   "thermal_cooling");
600	if (result) {
601		dev_err(&pdev->dev, "Failed to create sysfs link 'thermal_cooling'\n");
602		goto err_unregister;
603	}
604
605	result = sysfs_create_link(&cdev->device.kobj,
606				   &pdev->dev.kobj,
607				   "device");
608	if (result) {
609		dev_err(&pdev->dev, "Failed to create sysfs link 'device'\n");
610		goto err_remove_link;
611	}
612
613	return 0;
614
615err_remove_link:
616	sysfs_remove_link(&pdev->dev.kobj, "thermal_cooling");
617err_unregister:
618	thermal_cooling_device_unregister(cdev);
619err_end:
620	if (fan->has_fst)
621		acpi_fan_delete_attributes(device);
622
623	return result;
624}
625
626static void acpi_fan_remove(struct platform_device *pdev)
627{
628	struct acpi_fan *fan = platform_get_drvdata(pdev);
629
630	if (fan->has_fst) {
631		struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
632
633		acpi_fan_delete_attributes(device);
634	}
635	sysfs_remove_link(&pdev->dev.kobj, "thermal_cooling");
636	sysfs_remove_link(&fan->cdev->device.kobj, "device");
637	thermal_cooling_device_unregister(fan->cdev);
638}
639
640#ifdef CONFIG_PM_SLEEP
641static int acpi_fan_suspend(struct device *dev)
642{
643	struct acpi_fan *fan = dev_get_drvdata(dev);
644	if (fan->acpi4)
645		return 0;
646
647	acpi_device_set_power(ACPI_COMPANION(dev), ACPI_STATE_D0);
648
649	return AE_OK;
650}
651
652static int acpi_fan_resume(struct device *dev)
653{
654	struct acpi_fan *fan = dev_get_drvdata(dev);
655	int result;
656
657	if (fan->has_fst) {
658		result = acpi_fan_dsm_start(dev);
659		if (result)
660			dev_err(dev, "Failed to start Microsoft fan extensions: %d\n", result);
661	}
662
663	if (fan->acpi4)
664		return 0;
665
666	result = acpi_device_update_power(ACPI_COMPANION(dev), NULL);
667	if (result)
668		dev_err(dev, "Error updating fan power state\n");
669
670	return result;
671}
672
673static const struct dev_pm_ops acpi_fan_pm = {
674	.resume = acpi_fan_resume,
675	.freeze = acpi_fan_suspend,
676	.thaw = acpi_fan_resume,
677	.restore = acpi_fan_resume,
678};
679#define FAN_PM_OPS_PTR (&acpi_fan_pm)
680
681#else
682
683#define FAN_PM_OPS_PTR NULL
684
685#endif
686
687static struct platform_driver acpi_fan_driver = {
688	.probe = acpi_fan_probe,
689	.remove = acpi_fan_remove,
690	.driver = {
691		.name = "acpi-fan",
692		.acpi_match_table = fan_device_ids,
693		.pm = FAN_PM_OPS_PTR,
694	},
695};
696
697module_platform_driver(acpi_fan_driver);
698
699MODULE_AUTHOR("Paul Diefenbaugh");
700MODULE_DESCRIPTION("ACPI Fan Driver");
701MODULE_LICENSE("GPL");