1/*
2 *  dock.c - ACPI dock station driver
3 *
4 *  Copyright (C) 2006, 2014, Intel Corp.
5 *  Author: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
6 *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
7 *
8 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
9 *
10 *  This program is free software; you can redistribute it and/or modify
11 *  it under the terms of the GNU General Public License as published by
12 *  the Free Software Foundation; either version 2 of the License, or (at
13 *  your option) any later version.
14 *
15 *  This program is distributed in the hope that it will be useful, but
16 *  WITHOUT ANY WARRANTY; without even the implied warranty of
17 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 *  General Public License for more details.
19 *
20 *  You should have received a copy of the GNU General Public License along
21 *  with this program; if not, write to the Free Software Foundation, Inc.,
22 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
23 *
24 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
25 */
26
27#include <linux/kernel.h>
28#include <linux/module.h>
29#include <linux/slab.h>
30#include <linux/init.h>
31#include <linux/types.h>
32#include <linux/notifier.h>
33#include <linux/platform_device.h>
34#include <linux/jiffies.h>
35#include <linux/stddef.h>
36#include <linux/acpi.h>
37
38#include "internal.h"
39
40#define ACPI_DOCK_DRIVER_DESCRIPTION "ACPI Dock Station Driver"
41
42ACPI_MODULE_NAME("dock");
43MODULE_AUTHOR("Kristen Carlson Accardi");
44MODULE_DESCRIPTION(ACPI_DOCK_DRIVER_DESCRIPTION);
45MODULE_LICENSE("GPL");
46
47static bool immediate_undock = 1;
48module_param(immediate_undock, bool, 0644);
49MODULE_PARM_DESC(immediate_undock, "1 (default) will cause the driver to "
50	"undock immediately when the undock button is pressed, 0 will cause"
51	" the driver to wait for userspace to write the undock sysfs file "
52	" before undocking");
53
54struct dock_station {
55	acpi_handle handle;
56	unsigned long last_dock_time;
57	u32 flags;
58	struct list_head dependent_devices;
59
60	struct list_head sibling;
61	struct platform_device *dock_device;
62};
63static LIST_HEAD(dock_stations);
64static int dock_station_count;
65
66struct dock_dependent_device {
67	struct list_head list;
68	struct acpi_device *adev;
69};
70
71#define DOCK_DOCKING	0x00000001
72#define DOCK_UNDOCKING  0x00000002
73#define DOCK_IS_DOCK	0x00000010
74#define DOCK_IS_ATA	0x00000020
75#define DOCK_IS_BAT	0x00000040
76#define DOCK_EVENT	3
77#define UNDOCK_EVENT	2
78
79enum dock_callback_type {
80	DOCK_CALL_HANDLER,
81	DOCK_CALL_FIXUP,
82	DOCK_CALL_UEVENT,
83};
84
85/*****************************************************************************
86 *                         Dock Dependent device functions                   *
87 *****************************************************************************/
88/**
89 * add_dock_dependent_device - associate a device with the dock station
90 * @ds: Dock station.
91 * @adev: Dependent ACPI device object.
92 *
93 * Add the dependent device to the dock's dependent device list.
94 */
95static int add_dock_dependent_device(struct dock_station *ds,
96				     struct acpi_device *adev)
97{
98	struct dock_dependent_device *dd;
99
100	dd = kzalloc(sizeof(*dd), GFP_KERNEL);
101	if (!dd)
102		return -ENOMEM;
103
104	dd->adev = adev;
105	INIT_LIST_HEAD(&dd->list);
106	list_add_tail(&dd->list, &ds->dependent_devices);
107
108	return 0;
109}
110
111static void dock_hotplug_event(struct dock_dependent_device *dd, u32 event,
112			       enum dock_callback_type cb_type)
113{
114	struct acpi_device *adev = dd->adev;
115
116	acpi_lock_hp_context();
117
118	if (!adev->hp)
119		goto out;
120
121	if (cb_type == DOCK_CALL_FIXUP) {
122		void (*fixup)(struct acpi_device *);
123
124		fixup = adev->hp->fixup;
125		if (fixup) {
126			acpi_unlock_hp_context();
127			fixup(adev);
128			return;
129		}
130	} else if (cb_type == DOCK_CALL_UEVENT) {
131		void (*uevent)(struct acpi_device *, u32);
132
133		uevent = adev->hp->uevent;
134		if (uevent) {
135			acpi_unlock_hp_context();
136			uevent(adev, event);
137			return;
138		}
139	} else {
140		int (*notify)(struct acpi_device *, u32);
141
142		notify = adev->hp->notify;
143		if (notify) {
144			acpi_unlock_hp_context();
145			notify(adev, event);
146			return;
147		}
148	}
149
150 out:
151	acpi_unlock_hp_context();
152}
153
154static struct dock_station *find_dock_station(acpi_handle handle)
155{
156	struct dock_station *ds;
157
158	list_for_each_entry(ds, &dock_stations, sibling)
159		if (ds->handle == handle)
160			return ds;
161
162	return NULL;
163}
164
165/**
166 * find_dock_dependent_device - get a device dependent on this dock
167 * @ds: the dock station
168 * @adev: ACPI device object to find.
169 *
170 * iterate over the dependent device list for this dock.  If the
171 * dependent device matches the handle, return.
172 */
173static struct dock_dependent_device *
174find_dock_dependent_device(struct dock_station *ds, struct acpi_device *adev)
175{
176	struct dock_dependent_device *dd;
177
178	list_for_each_entry(dd, &ds->dependent_devices, list)
179		if (adev == dd->adev)
180			return dd;
181
182	return NULL;
183}
184
185void register_dock_dependent_device(struct acpi_device *adev,
186				    acpi_handle dshandle)
187{
188	struct dock_station *ds = find_dock_station(dshandle);
189
190	if (ds && !find_dock_dependent_device(ds, adev))
191		add_dock_dependent_device(ds, adev);
192}
193
194/*****************************************************************************
195 *                         Dock functions                                    *
196 *****************************************************************************/
197
198/**
199 * is_dock_device - see if a device is on a dock station
200 * @adev: ACPI device object to check.
201 *
202 * If this device is either the dock station itself,
203 * or is a device dependent on the dock station, then it
204 * is a dock device
205 */
206int is_dock_device(struct acpi_device *adev)
207{
208	struct dock_station *dock_station;
209
210	if (!dock_station_count)
211		return 0;
212
213	if (acpi_dock_match(adev->handle))
214		return 1;
215
216	list_for_each_entry(dock_station, &dock_stations, sibling)
217		if (find_dock_dependent_device(dock_station, adev))
218			return 1;
219
220	return 0;
221}
222EXPORT_SYMBOL_GPL(is_dock_device);
223
224/**
225 * dock_present - see if the dock station is present.
226 * @ds: the dock station
227 *
228 * execute the _STA method.  note that present does not
229 * imply that we are docked.
230 */
231static int dock_present(struct dock_station *ds)
232{
233	unsigned long long sta;
234	acpi_status status;
235
236	if (ds) {
237		status = acpi_evaluate_integer(ds->handle, "_STA", NULL, &sta);
238		if (ACPI_SUCCESS(status) && sta)
239			return 1;
240	}
241	return 0;
242}
243
244/**
245 * hot_remove_dock_devices - Remove dock station devices.
246 * @ds: Dock station.
247 */
248static void hot_remove_dock_devices(struct dock_station *ds)
249{
250	struct dock_dependent_device *dd;
251
252	/*
253	 * Walk the list in reverse order so that devices that have been added
254	 * last are removed first (in case there are some indirect dependencies
255	 * between them).
256	 */
257	list_for_each_entry_reverse(dd, &ds->dependent_devices, list)
258		dock_hotplug_event(dd, ACPI_NOTIFY_EJECT_REQUEST, false);
259
260	list_for_each_entry_reverse(dd, &ds->dependent_devices, list)
261		acpi_bus_trim(dd->adev);
262}
263
264/**
265 * hotplug_dock_devices - Insert devices on a dock station.
266 * @ds: the dock station
267 * @event: either bus check or device check request
268 *
269 * Some devices on the dock station need to have drivers called
270 * to perform hotplug operations after a dock event has occurred.
271 * Traverse the list of dock devices that have registered a
272 * hotplug handler, and call the handler.
273 */
274static void hotplug_dock_devices(struct dock_station *ds, u32 event)
275{
276	struct dock_dependent_device *dd;
277
278	/* Call driver specific post-dock fixups. */
279	list_for_each_entry(dd, &ds->dependent_devices, list)
280		dock_hotplug_event(dd, event, DOCK_CALL_FIXUP);
281
282	/* Call driver specific hotplug functions. */
283	list_for_each_entry(dd, &ds->dependent_devices, list)
284		dock_hotplug_event(dd, event, DOCK_CALL_HANDLER);
285
286	/*
287	 * Check if all devices have been enumerated already.  If not, run
288	 * acpi_bus_scan() for them and that will cause scan handlers to be
289	 * attached to device objects or acpi_drivers to be stopped/started if
290	 * they are present.
291	 */
292	list_for_each_entry(dd, &ds->dependent_devices, list) {
293		struct acpi_device *adev = dd->adev;
294
295		if (!acpi_device_enumerated(adev)) {
296			int ret = acpi_bus_scan(adev->handle);
297			if (ret)
298				dev_dbg(&adev->dev, "scan error %d\n", -ret);
299		}
300	}
301}
302
303static void dock_event(struct dock_station *ds, u32 event, int num)
304{
305	struct device *dev = &ds->dock_device->dev;
306	char event_string[13];
307	char *envp[] = { event_string, NULL };
308	struct dock_dependent_device *dd;
309
310	if (num == UNDOCK_EVENT)
311		sprintf(event_string, "EVENT=undock");
312	else
313		sprintf(event_string, "EVENT=dock");
314
315	/*
316	 * Indicate that the status of the dock station has
317	 * changed.
318	 */
319	if (num == DOCK_EVENT)
320		kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
321
322	list_for_each_entry(dd, &ds->dependent_devices, list)
323		dock_hotplug_event(dd, event, DOCK_CALL_UEVENT);
324
325	if (num != DOCK_EVENT)
326		kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);
327}
328
329/**
330 * handle_dock - handle a dock event
331 * @ds: the dock station
332 * @dock: to dock, or undock - that is the question
333 *
334 * Execute the _DCK method in response to an acpi event
335 */
336static void handle_dock(struct dock_station *ds, int dock)
337{
338	acpi_status status;
339	struct acpi_object_list arg_list;
340	union acpi_object arg;
341	unsigned long long value;
342
343	acpi_handle_info(ds->handle, "%s\n", dock ? "docking" : "undocking");
344
345	/* _DCK method has one argument */
346	arg_list.count = 1;
347	arg_list.pointer = &arg;
348	arg.type = ACPI_TYPE_INTEGER;
349	arg.integer.value = dock;
350	status = acpi_evaluate_integer(ds->handle, "_DCK", &arg_list, &value);
351	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND)
352		acpi_handle_err(ds->handle, "Failed to execute _DCK (0x%x)\n",
353				status);
354}
355
356static inline void dock(struct dock_station *ds)
357{
358	handle_dock(ds, 1);
359}
360
361static inline void undock(struct dock_station *ds)
362{
363	handle_dock(ds, 0);
364}
365
366static inline void begin_dock(struct dock_station *ds)
367{
368	ds->flags |= DOCK_DOCKING;
369}
370
371static inline void complete_dock(struct dock_station *ds)
372{
373	ds->flags &= ~(DOCK_DOCKING);
374	ds->last_dock_time = jiffies;
375}
376
377static inline void begin_undock(struct dock_station *ds)
378{
379	ds->flags |= DOCK_UNDOCKING;
380}
381
382static inline void complete_undock(struct dock_station *ds)
383{
384	ds->flags &= ~(DOCK_UNDOCKING);
385}
386
387/**
388 * dock_in_progress - see if we are in the middle of handling a dock event
389 * @ds: the dock station
390 *
391 * Sometimes while docking, false dock events can be sent to the driver
392 * because good connections aren't made or some other reason.  Ignore these
393 * if we are in the middle of doing something.
394 */
395static int dock_in_progress(struct dock_station *ds)
396{
397	if ((ds->flags & DOCK_DOCKING) ||
398	    time_before(jiffies, (ds->last_dock_time + HZ)))
399		return 1;
400	return 0;
401}
402
403/**
404 * handle_eject_request - handle an undock request checking for error conditions
405 *
406 * Check to make sure the dock device is still present, then undock and
407 * hotremove all the devices that may need removing.
408 */
409static int handle_eject_request(struct dock_station *ds, u32 event)
410{
411	if (dock_in_progress(ds))
412		return -EBUSY;
413
414	/*
415	 * here we need to generate the undock
416	 * event prior to actually doing the undock
417	 * so that the device struct still exists.
418	 * Also, even send the dock event if the
419	 * device is not present anymore
420	 */
421	dock_event(ds, event, UNDOCK_EVENT);
422
423	hot_remove_dock_devices(ds);
424	undock(ds);
425	acpi_evaluate_lck(ds->handle, 0);
426	acpi_evaluate_ej0(ds->handle);
427	if (dock_present(ds)) {
428		acpi_handle_err(ds->handle, "Unable to undock!\n");
429		return -EBUSY;
430	}
431	complete_undock(ds);
432	return 0;
433}
434
435/**
436 * dock_notify - Handle ACPI dock notification.
437 * @adev: Dock station's ACPI device object.
438 * @event: Event code.
439 *
440 * If we are notified to dock, then check to see if the dock is
441 * present and then dock.  Notify all drivers of the dock event,
442 * and then hotplug and devices that may need hotplugging.
443 */
444int dock_notify(struct acpi_device *adev, u32 event)
445{
446	acpi_handle handle = adev->handle;
447	struct dock_station *ds = find_dock_station(handle);
448	int surprise_removal = 0;
449
450	if (!ds)
451		return -ENODEV;
452
453	/*
454	 * According to acpi spec 3.0a, if a DEVICE_CHECK notification
455	 * is sent and _DCK is present, it is assumed to mean an undock
456	 * request.
457	 */
458	if ((ds->flags & DOCK_IS_DOCK) && event == ACPI_NOTIFY_DEVICE_CHECK)
459		event = ACPI_NOTIFY_EJECT_REQUEST;
460
461	/*
462	 * dock station: BUS_CHECK - docked or surprise removal
463	 *		 DEVICE_CHECK - undocked
464	 * other device: BUS_CHECK/DEVICE_CHECK - added or surprise removal
465	 *
466	 * To simplify event handling, dock dependent device handler always
467	 * get ACPI_NOTIFY_BUS_CHECK/ACPI_NOTIFY_DEVICE_CHECK for add and
468	 * ACPI_NOTIFY_EJECT_REQUEST for removal
469	 */
470	switch (event) {
471	case ACPI_NOTIFY_BUS_CHECK:
472	case ACPI_NOTIFY_DEVICE_CHECK:
473		if (!dock_in_progress(ds) && !acpi_device_enumerated(adev)) {
474			begin_dock(ds);
475			dock(ds);
476			if (!dock_present(ds)) {
477				acpi_handle_err(handle, "Unable to dock!\n");
478				complete_dock(ds);
479				break;
480			}
481			hotplug_dock_devices(ds, event);
482			complete_dock(ds);
483			dock_event(ds, event, DOCK_EVENT);
484			acpi_evaluate_lck(ds->handle, 1);
485			acpi_update_all_gpes();
486			break;
487		}
488		if (dock_present(ds) || dock_in_progress(ds))
489			break;
490		/* This is a surprise removal */
491		surprise_removal = 1;
492		event = ACPI_NOTIFY_EJECT_REQUEST;
493		/* Fall back */
494	case ACPI_NOTIFY_EJECT_REQUEST:
495		begin_undock(ds);
496		if ((immediate_undock && !(ds->flags & DOCK_IS_ATA))
497		   || surprise_removal)
498			handle_eject_request(ds, event);
499		else
500			dock_event(ds, event, UNDOCK_EVENT);
501		break;
502	}
503	return 0;
504}
505
506/*
507 * show_docked - read method for "docked" file in sysfs
508 */
509static ssize_t show_docked(struct device *dev,
510			   struct device_attribute *attr, char *buf)
511{
512	struct dock_station *dock_station = dev->platform_data;
513	struct acpi_device *adev = NULL;
514
515	acpi_bus_get_device(dock_station->handle, &adev);
516	return snprintf(buf, PAGE_SIZE, "%u\n", acpi_device_enumerated(adev));
517}
518static DEVICE_ATTR(docked, S_IRUGO, show_docked, NULL);
519
520/*
521 * show_flags - read method for flags file in sysfs
522 */
523static ssize_t show_flags(struct device *dev,
524			  struct device_attribute *attr, char *buf)
525{
526	struct dock_station *dock_station = dev->platform_data;
527	return snprintf(buf, PAGE_SIZE, "%d\n", dock_station->flags);
528
529}
530static DEVICE_ATTR(flags, S_IRUGO, show_flags, NULL);
531
532/*
533 * write_undock - write method for "undock" file in sysfs
534 */
535static ssize_t write_undock(struct device *dev, struct device_attribute *attr,
536			   const char *buf, size_t count)
537{
538	int ret;
539	struct dock_station *dock_station = dev->platform_data;
540
541	if (!count)
542		return -EINVAL;
543
544	acpi_scan_lock_acquire();
545	begin_undock(dock_station);
546	ret = handle_eject_request(dock_station, ACPI_NOTIFY_EJECT_REQUEST);
547	acpi_scan_lock_release();
548	return ret ? ret: count;
549}
550static DEVICE_ATTR(undock, S_IWUSR, NULL, write_undock);
551
552/*
553 * show_dock_uid - read method for "uid" file in sysfs
554 */
555static ssize_t show_dock_uid(struct device *dev,
556			     struct device_attribute *attr, char *buf)
557{
558	unsigned long long lbuf;
559	struct dock_station *dock_station = dev->platform_data;
560	acpi_status status = acpi_evaluate_integer(dock_station->handle,
561					"_UID", NULL, &lbuf);
562	if (ACPI_FAILURE(status))
563	    return 0;
564
565	return snprintf(buf, PAGE_SIZE, "%llx\n", lbuf);
566}
567static DEVICE_ATTR(uid, S_IRUGO, show_dock_uid, NULL);
568
569static ssize_t show_dock_type(struct device *dev,
570		struct device_attribute *attr, char *buf)
571{
572	struct dock_station *dock_station = dev->platform_data;
573	char *type;
574
575	if (dock_station->flags & DOCK_IS_DOCK)
576		type = "dock_station";
577	else if (dock_station->flags & DOCK_IS_ATA)
578		type = "ata_bay";
579	else if (dock_station->flags & DOCK_IS_BAT)
580		type = "battery_bay";
581	else
582		type = "unknown";
583
584	return snprintf(buf, PAGE_SIZE, "%s\n", type);
585}
586static DEVICE_ATTR(type, S_IRUGO, show_dock_type, NULL);
587
588static struct attribute *dock_attributes[] = {
589	&dev_attr_docked.attr,
590	&dev_attr_flags.attr,
591	&dev_attr_undock.attr,
592	&dev_attr_uid.attr,
593	&dev_attr_type.attr,
594	NULL
595};
596
597static struct attribute_group dock_attribute_group = {
598	.attrs = dock_attributes
599};
600
601/**
602 * acpi_dock_add - Add a new dock station
603 * @adev: Dock station ACPI device object.
604 *
605 * allocated and initialize a new dock station device.
606 */
607void acpi_dock_add(struct acpi_device *adev)
608{
609	struct dock_station *dock_station, ds = { NULL, };
610	struct platform_device_info pdevinfo;
611	acpi_handle handle = adev->handle;
612	struct platform_device *dd;
613	int ret;
614
615	memset(&pdevinfo, 0, sizeof(pdevinfo));
616	pdevinfo.name = "dock";
617	pdevinfo.id = dock_station_count;
618	pdevinfo.fwnode = acpi_fwnode_handle(adev);
619	pdevinfo.data = &ds;
620	pdevinfo.size_data = sizeof(ds);
621	dd = platform_device_register_full(&pdevinfo);
622	if (IS_ERR(dd))
623		return;
624
625	dock_station = dd->dev.platform_data;
626
627	dock_station->handle = handle;
628	dock_station->dock_device = dd;
629	dock_station->last_dock_time = jiffies - HZ;
630
631	INIT_LIST_HEAD(&dock_station->sibling);
632	INIT_LIST_HEAD(&dock_station->dependent_devices);
633
634	/* we want the dock device to send uevents */
635	dev_set_uevent_suppress(&dd->dev, 0);
636
637	if (acpi_dock_match(handle))
638		dock_station->flags |= DOCK_IS_DOCK;
639	if (acpi_ata_match(handle))
640		dock_station->flags |= DOCK_IS_ATA;
641	if (acpi_device_is_battery(adev))
642		dock_station->flags |= DOCK_IS_BAT;
643
644	ret = sysfs_create_group(&dd->dev.kobj, &dock_attribute_group);
645	if (ret)
646		goto err_unregister;
647
648	/* add the dock station as a device dependent on itself */
649	ret = add_dock_dependent_device(dock_station, adev);
650	if (ret)
651		goto err_rmgroup;
652
653	dock_station_count++;
654	list_add(&dock_station->sibling, &dock_stations);
655	adev->flags.is_dock_station = true;
656	dev_info(&adev->dev, "ACPI dock station (docks/bays count: %d)\n",
657		 dock_station_count);
658	return;
659
660err_rmgroup:
661	sysfs_remove_group(&dd->dev.kobj, &dock_attribute_group);
662
663err_unregister:
664	platform_device_unregister(dd);
665	acpi_handle_err(handle, "%s encountered error %d\n", __func__, ret);
666}
667