1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  dock.c - ACPI dock station driver
4  *
5  *  Copyright (C) 2006, 2014, Intel Corp.
6  *  Author: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
7  *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/moduleparam.h>
12 #include <linux/slab.h>
13 #include <linux/init.h>
14 #include <linux/types.h>
15 #include <linux/notifier.h>
16 #include <linux/platform_device.h>
17 #include <linux/jiffies.h>
18 #include <linux/stddef.h>
19 #include <linux/acpi.h>
20 
21 #include "internal.h"
22 
23 static bool immediate_undock = 1;
24 module_param(immediate_undock, bool, 0644);
25 MODULE_PARM_DESC(immediate_undock, "1 (default) will cause the driver to "
26 	"undock immediately when the undock button is pressed, 0 will cause"
27 	" the driver to wait for userspace to write the undock sysfs file "
28 	" before undocking");
29 
30 struct dock_station {
31 	acpi_handle handle;
32 	unsigned long last_dock_time;
33 	u32 flags;
34 	struct list_head dependent_devices;
35 
36 	struct list_head sibling;
37 	struct platform_device *dock_device;
38 };
39 static LIST_HEAD(dock_stations);
40 static int dock_station_count;
41 
42 struct dock_dependent_device {
43 	struct list_head list;
44 	struct acpi_device *adev;
45 };
46 
47 #define DOCK_DOCKING	0x00000001
48 #define DOCK_UNDOCKING  0x00000002
49 #define DOCK_IS_DOCK	0x00000010
50 #define DOCK_IS_ATA	0x00000020
51 #define DOCK_IS_BAT	0x00000040
52 #define DOCK_EVENT	3
53 #define UNDOCK_EVENT	2
54 
55 enum dock_callback_type {
56 	DOCK_CALL_HANDLER,
57 	DOCK_CALL_FIXUP,
58 	DOCK_CALL_UEVENT,
59 };
60 
61 /*****************************************************************************
62  *                         Dock Dependent device functions                   *
63  *****************************************************************************/
64 /**
65  * add_dock_dependent_device - associate a device with the dock station
66  * @ds: Dock station.
67  * @adev: Dependent ACPI device object.
68  *
69  * Add the dependent device to the dock's dependent device list.
70  */
add_dock_dependent_device(struct dock_station * ds,struct acpi_device * adev)71 static int add_dock_dependent_device(struct dock_station *ds,
72 				     struct acpi_device *adev)
73 {
74 	struct dock_dependent_device *dd;
75 
76 	dd = kzalloc(sizeof(*dd), GFP_KERNEL);
77 	if (!dd)
78 		return -ENOMEM;
79 
80 	dd->adev = adev;
81 	INIT_LIST_HEAD(&dd->list);
82 	list_add_tail(&dd->list, &ds->dependent_devices);
83 
84 	return 0;
85 }
86 
dock_hotplug_event(struct dock_dependent_device * dd,u32 event,enum dock_callback_type cb_type)87 static void dock_hotplug_event(struct dock_dependent_device *dd, u32 event,
88 			       enum dock_callback_type cb_type)
89 {
90 	struct acpi_device *adev = dd->adev;
91 
92 	acpi_lock_hp_context();
93 
94 	if (!adev->hp)
95 		goto out;
96 
97 	if (cb_type == DOCK_CALL_FIXUP) {
98 		void (*fixup)(struct acpi_device *);
99 
100 		fixup = adev->hp->fixup;
101 		if (fixup) {
102 			acpi_unlock_hp_context();
103 			fixup(adev);
104 			return;
105 		}
106 	} else if (cb_type == DOCK_CALL_UEVENT) {
107 		void (*uevent)(struct acpi_device *, u32);
108 
109 		uevent = adev->hp->uevent;
110 		if (uevent) {
111 			acpi_unlock_hp_context();
112 			uevent(adev, event);
113 			return;
114 		}
115 	} else {
116 		int (*notify)(struct acpi_device *, u32);
117 
118 		notify = adev->hp->notify;
119 		if (notify) {
120 			acpi_unlock_hp_context();
121 			notify(adev, event);
122 			return;
123 		}
124 	}
125 
126  out:
127 	acpi_unlock_hp_context();
128 }
129 
find_dock_station(acpi_handle handle)130 static struct dock_station *find_dock_station(acpi_handle handle)
131 {
132 	struct dock_station *ds;
133 
134 	list_for_each_entry(ds, &dock_stations, sibling)
135 		if (ds->handle == handle)
136 			return ds;
137 
138 	return NULL;
139 }
140 
141 /**
142  * find_dock_dependent_device - get a device dependent on this dock
143  * @ds: the dock station
144  * @adev: ACPI device object to find.
145  *
146  * iterate over the dependent device list for this dock.  If the
147  * dependent device matches the handle, return.
148  */
149 static struct dock_dependent_device *
find_dock_dependent_device(struct dock_station * ds,struct acpi_device * adev)150 find_dock_dependent_device(struct dock_station *ds, struct acpi_device *adev)
151 {
152 	struct dock_dependent_device *dd;
153 
154 	list_for_each_entry(dd, &ds->dependent_devices, list)
155 		if (adev == dd->adev)
156 			return dd;
157 
158 	return NULL;
159 }
160 
register_dock_dependent_device(struct acpi_device * adev,acpi_handle dshandle)161 void register_dock_dependent_device(struct acpi_device *adev,
162 				    acpi_handle dshandle)
163 {
164 	struct dock_station *ds = find_dock_station(dshandle);
165 
166 	if (ds && !find_dock_dependent_device(ds, adev))
167 		add_dock_dependent_device(ds, adev);
168 }
169 
170 /*****************************************************************************
171  *                         Dock functions                                    *
172  *****************************************************************************/
173 
174 /**
175  * is_dock_device - see if a device is on a dock station
176  * @adev: ACPI device object to check.
177  *
178  * If this device is either the dock station itself,
179  * or is a device dependent on the dock station, then it
180  * is a dock device
181  */
is_dock_device(struct acpi_device * adev)182 int is_dock_device(struct acpi_device *adev)
183 {
184 	struct dock_station *dock_station;
185 
186 	if (!dock_station_count)
187 		return 0;
188 
189 	if (acpi_dock_match(adev->handle))
190 		return 1;
191 
192 	list_for_each_entry(dock_station, &dock_stations, sibling)
193 		if (find_dock_dependent_device(dock_station, adev))
194 			return 1;
195 
196 	return 0;
197 }
198 EXPORT_SYMBOL_GPL(is_dock_device);
199 
200 /**
201  * dock_present - see if the dock station is present.
202  * @ds: the dock station
203  *
204  * execute the _STA method.  note that present does not
205  * imply that we are docked.
206  */
dock_present(struct dock_station * ds)207 static int dock_present(struct dock_station *ds)
208 {
209 	unsigned long long sta;
210 	acpi_status status;
211 
212 	if (ds) {
213 		status = acpi_evaluate_integer(ds->handle, "_STA", NULL, &sta);
214 		if (ACPI_SUCCESS(status) && sta)
215 			return 1;
216 	}
217 	return 0;
218 }
219 
220 /**
221  * hot_remove_dock_devices - Remove dock station devices.
222  * @ds: Dock station.
223  */
hot_remove_dock_devices(struct dock_station * ds)224 static void hot_remove_dock_devices(struct dock_station *ds)
225 {
226 	struct dock_dependent_device *dd;
227 
228 	/*
229 	 * Walk the list in reverse order so that devices that have been added
230 	 * last are removed first (in case there are some indirect dependencies
231 	 * between them).
232 	 */
233 	list_for_each_entry_reverse(dd, &ds->dependent_devices, list)
234 		dock_hotplug_event(dd, ACPI_NOTIFY_EJECT_REQUEST,
235 				   DOCK_CALL_HANDLER);
236 
237 	list_for_each_entry_reverse(dd, &ds->dependent_devices, list)
238 		acpi_bus_trim(dd->adev);
239 }
240 
241 /**
242  * hotplug_dock_devices - Insert devices on a dock station.
243  * @ds: the dock station
244  * @event: either bus check or device check request
245  *
246  * Some devices on the dock station need to have drivers called
247  * to perform hotplug operations after a dock event has occurred.
248  * Traverse the list of dock devices that have registered a
249  * hotplug handler, and call the handler.
250  */
hotplug_dock_devices(struct dock_station * ds,u32 event)251 static void hotplug_dock_devices(struct dock_station *ds, u32 event)
252 {
253 	struct dock_dependent_device *dd;
254 
255 	/* Call driver specific post-dock fixups. */
256 	list_for_each_entry(dd, &ds->dependent_devices, list)
257 		dock_hotplug_event(dd, event, DOCK_CALL_FIXUP);
258 
259 	/* Call driver specific hotplug functions. */
260 	list_for_each_entry(dd, &ds->dependent_devices, list)
261 		dock_hotplug_event(dd, event, DOCK_CALL_HANDLER);
262 
263 	/*
264 	 * Check if all devices have been enumerated already.  If not, run
265 	 * acpi_bus_scan() for them and that will cause scan handlers to be
266 	 * attached to device objects or acpi_drivers to be stopped/started if
267 	 * they are present.
268 	 */
269 	list_for_each_entry(dd, &ds->dependent_devices, list) {
270 		struct acpi_device *adev = dd->adev;
271 
272 		if (!acpi_device_enumerated(adev)) {
273 			int ret = acpi_bus_scan(adev->handle);
274 
275 			if (ret)
276 				dev_dbg(&adev->dev, "scan error %d\n", -ret);
277 		}
278 	}
279 }
280 
dock_event(struct dock_station * ds,u32 event,int num)281 static void dock_event(struct dock_station *ds, u32 event, int num)
282 {
283 	struct device *dev = &ds->dock_device->dev;
284 	char event_string[13];
285 	char *envp[] = { event_string, NULL };
286 	struct dock_dependent_device *dd;
287 
288 	if (num == UNDOCK_EVENT)
289 		sprintf(event_string, "EVENT=undock");
290 	else
291 		sprintf(event_string, "EVENT=dock");
292 
293 	/*
294 	 * Indicate that the status of the dock station has
295 	 * changed.
296 	 */
297 	if (num == DOCK_EVENT)
298 		kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
299 
300 	list_for_each_entry(dd, &ds->dependent_devices, list)
301 		dock_hotplug_event(dd, event, DOCK_CALL_UEVENT);
302 
303 	if (num != DOCK_EVENT)
304 		kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
305 }
306 
307 /**
308  * handle_dock - handle a dock event
309  * @ds: the dock station
310  * @dock: to dock, or undock - that is the question
311  *
312  * Execute the _DCK method in response to an acpi event
313  */
handle_dock(struct dock_station * ds,int dock)314 static void handle_dock(struct dock_station *ds, int dock)
315 {
316 	acpi_status status;
317 	struct acpi_object_list arg_list;
318 	union acpi_object arg;
319 	unsigned long long value;
320 
321 	acpi_handle_info(ds->handle, "%s\n", dock ? "docking" : "undocking");
322 
323 	/* _DCK method has one argument */
324 	arg_list.count = 1;
325 	arg_list.pointer = &arg;
326 	arg.type = ACPI_TYPE_INTEGER;
327 	arg.integer.value = dock;
328 	status = acpi_evaluate_integer(ds->handle, "_DCK", &arg_list, &value);
329 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND)
330 		acpi_handle_err(ds->handle, "Failed to execute _DCK (0x%x)\n",
331 				status);
332 }
333 
dock(struct dock_station * ds)334 static inline void dock(struct dock_station *ds)
335 {
336 	handle_dock(ds, 1);
337 }
338 
undock(struct dock_station * ds)339 static inline void undock(struct dock_station *ds)
340 {
341 	handle_dock(ds, 0);
342 }
343 
begin_dock(struct dock_station * ds)344 static inline void begin_dock(struct dock_station *ds)
345 {
346 	ds->flags |= DOCK_DOCKING;
347 }
348 
complete_dock(struct dock_station * ds)349 static inline void complete_dock(struct dock_station *ds)
350 {
351 	ds->flags &= ~(DOCK_DOCKING);
352 	ds->last_dock_time = jiffies;
353 }
354 
begin_undock(struct dock_station * ds)355 static inline void begin_undock(struct dock_station *ds)
356 {
357 	ds->flags |= DOCK_UNDOCKING;
358 }
359 
complete_undock(struct dock_station * ds)360 static inline void complete_undock(struct dock_station *ds)
361 {
362 	ds->flags &= ~(DOCK_UNDOCKING);
363 }
364 
365 /**
366  * dock_in_progress - see if we are in the middle of handling a dock event
367  * @ds: the dock station
368  *
369  * Sometimes while docking, false dock events can be sent to the driver
370  * because good connections aren't made or some other reason.  Ignore these
371  * if we are in the middle of doing something.
372  */
dock_in_progress(struct dock_station * ds)373 static int dock_in_progress(struct dock_station *ds)
374 {
375 	if ((ds->flags & DOCK_DOCKING) ||
376 	    time_before(jiffies, (ds->last_dock_time + HZ)))
377 		return 1;
378 	return 0;
379 }
380 
381 /**
382  * handle_eject_request - handle an undock request checking for error conditions
383  *
384  * Check to make sure the dock device is still present, then undock and
385  * hotremove all the devices that may need removing.
386  */
handle_eject_request(struct dock_station * ds,u32 event)387 static int handle_eject_request(struct dock_station *ds, u32 event)
388 {
389 	if (dock_in_progress(ds))
390 		return -EBUSY;
391 
392 	/*
393 	 * here we need to generate the undock
394 	 * event prior to actually doing the undock
395 	 * so that the device struct still exists.
396 	 * Also, even send the dock event if the
397 	 * device is not present anymore
398 	 */
399 	dock_event(ds, event, UNDOCK_EVENT);
400 
401 	hot_remove_dock_devices(ds);
402 	undock(ds);
403 	acpi_evaluate_lck(ds->handle, 0);
404 	acpi_evaluate_ej0(ds->handle);
405 	if (dock_present(ds)) {
406 		acpi_handle_err(ds->handle, "Unable to undock!\n");
407 		return -EBUSY;
408 	}
409 	complete_undock(ds);
410 	return 0;
411 }
412 
413 /**
414  * dock_notify - Handle ACPI dock notification.
415  * @adev: Dock station's ACPI device object.
416  * @event: Event code.
417  *
418  * If we are notified to dock, then check to see if the dock is
419  * present and then dock.  Notify all drivers of the dock event,
420  * and then hotplug and devices that may need hotplugging.
421  */
dock_notify(struct acpi_device * adev,u32 event)422 int dock_notify(struct acpi_device *adev, u32 event)
423 {
424 	acpi_handle handle = adev->handle;
425 	struct dock_station *ds = find_dock_station(handle);
426 	int surprise_removal = 0;
427 
428 	if (!ds)
429 		return -ENODEV;
430 
431 	/*
432 	 * According to acpi spec 3.0a, if a DEVICE_CHECK notification
433 	 * is sent and _DCK is present, it is assumed to mean an undock
434 	 * request.
435 	 */
436 	if ((ds->flags & DOCK_IS_DOCK) && event == ACPI_NOTIFY_DEVICE_CHECK)
437 		event = ACPI_NOTIFY_EJECT_REQUEST;
438 
439 	/*
440 	 * dock station: BUS_CHECK - docked or surprise removal
441 	 *		 DEVICE_CHECK - undocked
442 	 * other device: BUS_CHECK/DEVICE_CHECK - added or surprise removal
443 	 *
444 	 * To simplify event handling, dock dependent device handler always
445 	 * get ACPI_NOTIFY_BUS_CHECK/ACPI_NOTIFY_DEVICE_CHECK for add and
446 	 * ACPI_NOTIFY_EJECT_REQUEST for removal
447 	 */
448 	switch (event) {
449 	case ACPI_NOTIFY_BUS_CHECK:
450 	case ACPI_NOTIFY_DEVICE_CHECK:
451 		if (!dock_in_progress(ds) && !acpi_device_enumerated(adev)) {
452 			begin_dock(ds);
453 			dock(ds);
454 			if (!dock_present(ds)) {
455 				acpi_handle_err(handle, "Unable to dock!\n");
456 				complete_dock(ds);
457 				break;
458 			}
459 			hotplug_dock_devices(ds, event);
460 			complete_dock(ds);
461 			dock_event(ds, event, DOCK_EVENT);
462 			acpi_evaluate_lck(ds->handle, 1);
463 			acpi_update_all_gpes();
464 			break;
465 		}
466 		if (dock_present(ds) || dock_in_progress(ds))
467 			break;
468 		/* This is a surprise removal */
469 		surprise_removal = 1;
470 		event = ACPI_NOTIFY_EJECT_REQUEST;
471 		/* Fall back */
472 		fallthrough;
473 	case ACPI_NOTIFY_EJECT_REQUEST:
474 		begin_undock(ds);
475 		if ((immediate_undock && !(ds->flags & DOCK_IS_ATA))
476 		   || surprise_removal)
477 			handle_eject_request(ds, event);
478 		else
479 			dock_event(ds, event, UNDOCK_EVENT);
480 		break;
481 	}
482 	return 0;
483 }
484 
485 /*
486  * show_docked - read method for "docked" file in sysfs
487  */
docked_show(struct device * dev,struct device_attribute * attr,char * buf)488 static ssize_t docked_show(struct device *dev,
489 			   struct device_attribute *attr, char *buf)
490 {
491 	struct dock_station *dock_station = dev->platform_data;
492 	struct acpi_device *adev = acpi_fetch_acpi_dev(dock_station->handle);
493 
494 	return sysfs_emit(buf, "%u\n", acpi_device_enumerated(adev));
495 }
496 static DEVICE_ATTR_RO(docked);
497 
498 /*
499  * show_flags - read method for flags file in sysfs
500  */
flags_show(struct device * dev,struct device_attribute * attr,char * buf)501 static ssize_t flags_show(struct device *dev,
502 			  struct device_attribute *attr, char *buf)
503 {
504 	struct dock_station *dock_station = dev->platform_data;
505 
506 	return sysfs_emit(buf, "%d\n", dock_station->flags);
507 
508 }
509 static DEVICE_ATTR_RO(flags);
510 
511 /*
512  * write_undock - write method for "undock" file in sysfs
513  */
undock_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)514 static ssize_t undock_store(struct device *dev, struct device_attribute *attr,
515 			    const char *buf, size_t count)
516 {
517 	int ret;
518 	struct dock_station *dock_station = dev->platform_data;
519 
520 	if (!count)
521 		return -EINVAL;
522 
523 	acpi_scan_lock_acquire();
524 	begin_undock(dock_station);
525 	ret = handle_eject_request(dock_station, ACPI_NOTIFY_EJECT_REQUEST);
526 	acpi_scan_lock_release();
527 	return ret ? ret : count;
528 }
529 static DEVICE_ATTR_WO(undock);
530 
531 /*
532  * show_dock_uid - read method for "uid" file in sysfs
533  */
uid_show(struct device * dev,struct device_attribute * attr,char * buf)534 static ssize_t uid_show(struct device *dev,
535 			struct device_attribute *attr, char *buf)
536 {
537 	unsigned long long lbuf;
538 	struct dock_station *dock_station = dev->platform_data;
539 
540 	acpi_status status = acpi_evaluate_integer(dock_station->handle,
541 					"_UID", NULL, &lbuf);
542 	if (ACPI_FAILURE(status))
543 		return 0;
544 
545 	return sysfs_emit(buf, "%llx\n", lbuf);
546 }
547 static DEVICE_ATTR_RO(uid);
548 
type_show(struct device * dev,struct device_attribute * attr,char * buf)549 static ssize_t type_show(struct device *dev,
550 			 struct device_attribute *attr, char *buf)
551 {
552 	struct dock_station *dock_station = dev->platform_data;
553 	char *type;
554 
555 	if (dock_station->flags & DOCK_IS_DOCK)
556 		type = "dock_station";
557 	else if (dock_station->flags & DOCK_IS_ATA)
558 		type = "ata_bay";
559 	else if (dock_station->flags & DOCK_IS_BAT)
560 		type = "battery_bay";
561 	else
562 		type = "unknown";
563 
564 	return sysfs_emit(buf, "%s\n", type);
565 }
566 static DEVICE_ATTR_RO(type);
567 
568 static struct attribute *dock_attributes[] = {
569 	&dev_attr_docked.attr,
570 	&dev_attr_flags.attr,
571 	&dev_attr_undock.attr,
572 	&dev_attr_uid.attr,
573 	&dev_attr_type.attr,
574 	NULL
575 };
576 
577 static const struct attribute_group dock_attribute_group = {
578 	.attrs = dock_attributes
579 };
580 
581 /**
582  * acpi_dock_add - Add a new dock station
583  * @adev: Dock station ACPI device object.
584  *
585  * allocated and initialize a new dock station device.
586  */
acpi_dock_add(struct acpi_device * adev)587 void acpi_dock_add(struct acpi_device *adev)
588 {
589 	struct dock_station *dock_station, ds = { NULL, };
590 	struct platform_device_info pdevinfo;
591 	acpi_handle handle = adev->handle;
592 	struct platform_device *dd;
593 	int ret;
594 
595 	memset(&pdevinfo, 0, sizeof(pdevinfo));
596 	pdevinfo.name = "dock";
597 	pdevinfo.id = dock_station_count;
598 	pdevinfo.fwnode = acpi_fwnode_handle(adev);
599 	pdevinfo.data = &ds;
600 	pdevinfo.size_data = sizeof(ds);
601 	dd = platform_device_register_full(&pdevinfo);
602 	if (IS_ERR(dd))
603 		return;
604 
605 	dock_station = dd->dev.platform_data;
606 
607 	dock_station->handle = handle;
608 	dock_station->dock_device = dd;
609 	dock_station->last_dock_time = jiffies - HZ;
610 
611 	INIT_LIST_HEAD(&dock_station->sibling);
612 	INIT_LIST_HEAD(&dock_station->dependent_devices);
613 
614 	/* we want the dock device to send uevents */
615 	dev_set_uevent_suppress(&dd->dev, 0);
616 
617 	if (acpi_dock_match(handle))
618 		dock_station->flags |= DOCK_IS_DOCK;
619 	if (acpi_ata_match(handle))
620 		dock_station->flags |= DOCK_IS_ATA;
621 	if (acpi_device_is_battery(adev))
622 		dock_station->flags |= DOCK_IS_BAT;
623 
624 	ret = sysfs_create_group(&dd->dev.kobj, &dock_attribute_group);
625 	if (ret)
626 		goto err_unregister;
627 
628 	/* add the dock station as a device dependent on itself */
629 	ret = add_dock_dependent_device(dock_station, adev);
630 	if (ret)
631 		goto err_rmgroup;
632 
633 	dock_station_count++;
634 	list_add(&dock_station->sibling, &dock_stations);
635 	adev->flags.is_dock_station = true;
636 	dev_info(&adev->dev, "ACPI dock station (docks/bays count: %d)\n",
637 		 dock_station_count);
638 	return;
639 
640 err_rmgroup:
641 	sysfs_remove_group(&dd->dev.kobj, &dock_attribute_group);
642 
643 err_unregister:
644 	platform_device_unregister(dd);
645 	acpi_handle_err(handle, "%s encountered error %d\n", __func__, ret);
646 }
647