1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Link physical devices with ACPI devices support
4 *
5 * Copyright (c) 2005 David Shaohua Li <shaohua.li@intel.com>
6 * Copyright (c) 2005 Intel Corp.
7 */
8
9#define pr_fmt(fmt) "ACPI: " fmt
10
11#include <linux/acpi_iort.h>
12#include <linux/export.h>
13#include <linux/init.h>
14#include <linux/list.h>
15#include <linux/device.h>
16#include <linux/slab.h>
17#include <linux/rwsem.h>
18#include <linux/acpi.h>
19#include <linux/dma-mapping.h>
20#include <linux/pci.h>
21#include <linux/pci-acpi.h>
22#include <linux/platform_device.h>
23
24#include "internal.h"
25
26static LIST_HEAD(bus_type_list);
27static DECLARE_RWSEM(bus_type_sem);
28
29#define PHYSICAL_NODE_STRING "physical_node"
30#define PHYSICAL_NODE_NAME_SIZE (sizeof(PHYSICAL_NODE_STRING) + 10)
31
32int register_acpi_bus_type(struct acpi_bus_type *type)
33{
34	if (acpi_disabled)
35		return -ENODEV;
36	if (type && type->match && type->find_companion) {
37		down_write(&bus_type_sem);
38		list_add_tail(&type->list, &bus_type_list);
39		up_write(&bus_type_sem);
40		pr_info("bus type %s registered\n", type->name);
41		return 0;
42	}
43	return -ENODEV;
44}
45EXPORT_SYMBOL_GPL(register_acpi_bus_type);
46
47int unregister_acpi_bus_type(struct acpi_bus_type *type)
48{
49	if (acpi_disabled)
50		return 0;
51	if (type) {
52		down_write(&bus_type_sem);
53		list_del_init(&type->list);
54		up_write(&bus_type_sem);
55		pr_info("bus type %s unregistered\n", type->name);
56		return 0;
57	}
58	return -ENODEV;
59}
60EXPORT_SYMBOL_GPL(unregister_acpi_bus_type);
61
62static struct acpi_bus_type *acpi_get_bus_type(struct device *dev)
63{
64	struct acpi_bus_type *tmp, *ret = NULL;
65
66	down_read(&bus_type_sem);
67	list_for_each_entry(tmp, &bus_type_list, list) {
68		if (tmp->match(dev)) {
69			ret = tmp;
70			break;
71		}
72	}
73	up_read(&bus_type_sem);
74	return ret;
75}
76
77#define FIND_CHILD_MIN_SCORE	1
78#define FIND_CHILD_MID_SCORE	2
79#define FIND_CHILD_MAX_SCORE	3
80
81static int match_any(struct acpi_device *adev, void *not_used)
82{
83	return 1;
84}
85
86static bool acpi_dev_has_children(struct acpi_device *adev)
87{
88	return acpi_dev_for_each_child(adev, match_any, NULL) > 0;
89}
90
91static int find_child_checks(struct acpi_device *adev, bool check_children)
92{
93	unsigned long long sta;
94	acpi_status status;
95
96	if (check_children && !acpi_dev_has_children(adev))
97		return -ENODEV;
98
99	status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta);
100	if (status == AE_NOT_FOUND) {
101		/*
102		 * Special case: backlight device objects without _STA are
103		 * preferred to other objects with the same _ADR value, because
104		 * it is more likely that they are actually useful.
105		 */
106		if (adev->pnp.type.backlight)
107			return FIND_CHILD_MID_SCORE;
108
109		return FIND_CHILD_MIN_SCORE;
110	}
111
112	if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_ENABLED))
113		return -ENODEV;
114
115	/*
116	 * If the device has a _HID returning a valid ACPI/PNP device ID, it is
117	 * better to make it look less attractive here, so that the other device
118	 * with the same _ADR value (that may not have a valid device ID) can be
119	 * matched going forward.  [This means a second spec violation in a row,
120	 * so whatever we do here is best effort anyway.]
121	 */
122	if (adev->pnp.type.platform_id)
123		return FIND_CHILD_MIN_SCORE;
124
125	return FIND_CHILD_MAX_SCORE;
126}
127
128struct find_child_walk_data {
129	struct acpi_device *adev;
130	u64 address;
131	int score;
132	bool check_sta;
133	bool check_children;
134};
135
136static int check_one_child(struct acpi_device *adev, void *data)
137{
138	struct find_child_walk_data *wd = data;
139	int score;
140
141	if (!adev->pnp.type.bus_address || acpi_device_adr(adev) != wd->address)
142		return 0;
143
144	if (!wd->adev) {
145		/*
146		 * This is the first matching object, so save it.  If it is not
147		 * necessary to look for any other matching objects, stop the
148		 * search.
149		 */
150		wd->adev = adev;
151		return !(wd->check_sta || wd->check_children);
152	}
153
154	/*
155	 * There is more than one matching device object with the same _ADR
156	 * value.  That really is unexpected, so we are kind of beyond the scope
157	 * of the spec here.  We have to choose which one to return, though.
158	 *
159	 * First, get the score for the previously found object and terminate
160	 * the walk if it is maximum.
161	*/
162	if (!wd->score) {
163		score = find_child_checks(wd->adev, wd->check_children);
164		if (score == FIND_CHILD_MAX_SCORE)
165			return 1;
166
167		wd->score = score;
168	}
169	/*
170	 * Second, if the object that has just been found has a better score,
171	 * replace the previously found one with it and terminate the walk if
172	 * the new score is maximum.
173	 */
174	score = find_child_checks(adev, wd->check_children);
175	if (score > wd->score) {
176		wd->adev = adev;
177		if (score == FIND_CHILD_MAX_SCORE)
178			return 1;
179
180		wd->score = score;
181	}
182
183	/* Continue, because there may be better matches. */
184	return 0;
185}
186
187static struct acpi_device *acpi_find_child(struct acpi_device *parent,
188					   u64 address, bool check_children,
189					   bool check_sta)
190{
191	struct find_child_walk_data wd = {
192		.address = address,
193		.check_children = check_children,
194		.check_sta = check_sta,
195		.adev = NULL,
196		.score = 0,
197	};
198
199	if (parent)
200		acpi_dev_for_each_child(parent, check_one_child, &wd);
201
202	return wd.adev;
203}
204
205struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
206					   u64 address, bool check_children)
207{
208	return acpi_find_child(parent, address, check_children, true);
209}
210EXPORT_SYMBOL_GPL(acpi_find_child_device);
211
212struct acpi_device *acpi_find_child_by_adr(struct acpi_device *adev,
213					   acpi_bus_address adr)
214{
215	return acpi_find_child(adev, adr, false, false);
216}
217EXPORT_SYMBOL_GPL(acpi_find_child_by_adr);
218
219static void acpi_physnode_link_name(char *buf, unsigned int node_id)
220{
221	if (node_id > 0)
222		snprintf(buf, PHYSICAL_NODE_NAME_SIZE,
223			 PHYSICAL_NODE_STRING "%u", node_id);
224	else
225		strcpy(buf, PHYSICAL_NODE_STRING);
226}
227
228int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev)
229{
230	struct acpi_device_physical_node *physical_node, *pn;
231	char physical_node_name[PHYSICAL_NODE_NAME_SIZE];
232	struct list_head *physnode_list;
233	unsigned int node_id;
234	int retval = -EINVAL;
235
236	if (has_acpi_companion(dev)) {
237		if (acpi_dev) {
238			dev_warn(dev, "ACPI companion already set\n");
239			return -EINVAL;
240		} else {
241			acpi_dev = ACPI_COMPANION(dev);
242		}
243	}
244	if (!acpi_dev)
245		return -EINVAL;
246
247	acpi_dev_get(acpi_dev);
248	get_device(dev);
249	physical_node = kzalloc(sizeof(*physical_node), GFP_KERNEL);
250	if (!physical_node) {
251		retval = -ENOMEM;
252		goto err;
253	}
254
255	mutex_lock(&acpi_dev->physical_node_lock);
256
257	/*
258	 * Keep the list sorted by node_id so that the IDs of removed nodes can
259	 * be recycled easily.
260	 */
261	physnode_list = &acpi_dev->physical_node_list;
262	node_id = 0;
263	list_for_each_entry(pn, &acpi_dev->physical_node_list, node) {
264		/* Sanity check. */
265		if (pn->dev == dev) {
266			mutex_unlock(&acpi_dev->physical_node_lock);
267
268			dev_warn(dev, "Already associated with ACPI node\n");
269			kfree(physical_node);
270			if (ACPI_COMPANION(dev) != acpi_dev)
271				goto err;
272
273			put_device(dev);
274			acpi_dev_put(acpi_dev);
275			return 0;
276		}
277		if (pn->node_id == node_id) {
278			physnode_list = &pn->node;
279			node_id++;
280		}
281	}
282
283	physical_node->node_id = node_id;
284	physical_node->dev = dev;
285	list_add(&physical_node->node, physnode_list);
286	acpi_dev->physical_node_count++;
287
288	if (!has_acpi_companion(dev))
289		ACPI_COMPANION_SET(dev, acpi_dev);
290
291	acpi_physnode_link_name(physical_node_name, node_id);
292	retval = sysfs_create_link(&acpi_dev->dev.kobj, &dev->kobj,
293				   physical_node_name);
294	if (retval)
295		dev_err(&acpi_dev->dev, "Failed to create link %s (%d)\n",
296			physical_node_name, retval);
297
298	retval = sysfs_create_link(&dev->kobj, &acpi_dev->dev.kobj,
299				   "firmware_node");
300	if (retval)
301		dev_err(dev, "Failed to create link firmware_node (%d)\n",
302			retval);
303
304	mutex_unlock(&acpi_dev->physical_node_lock);
305
306	if (acpi_dev->wakeup.flags.valid)
307		device_set_wakeup_capable(dev, true);
308
309	return 0;
310
311 err:
312	ACPI_COMPANION_SET(dev, NULL);
313	put_device(dev);
314	acpi_dev_put(acpi_dev);
315	return retval;
316}
317EXPORT_SYMBOL_GPL(acpi_bind_one);
318
319int acpi_unbind_one(struct device *dev)
320{
321	struct acpi_device *acpi_dev = ACPI_COMPANION(dev);
322	struct acpi_device_physical_node *entry;
323
324	if (!acpi_dev)
325		return 0;
326
327	mutex_lock(&acpi_dev->physical_node_lock);
328
329	list_for_each_entry(entry, &acpi_dev->physical_node_list, node)
330		if (entry->dev == dev) {
331			char physnode_name[PHYSICAL_NODE_NAME_SIZE];
332
333			list_del(&entry->node);
334			acpi_dev->physical_node_count--;
335
336			acpi_physnode_link_name(physnode_name, entry->node_id);
337			sysfs_remove_link(&acpi_dev->dev.kobj, physnode_name);
338			sysfs_remove_link(&dev->kobj, "firmware_node");
339			ACPI_COMPANION_SET(dev, NULL);
340			/* Drop references taken by acpi_bind_one(). */
341			put_device(dev);
342			acpi_dev_put(acpi_dev);
343			kfree(entry);
344			break;
345		}
346
347	mutex_unlock(&acpi_dev->physical_node_lock);
348	return 0;
349}
350EXPORT_SYMBOL_GPL(acpi_unbind_one);
351
352void acpi_device_notify(struct device *dev)
353{
354	struct acpi_device *adev;
355	int ret;
356
357	ret = acpi_bind_one(dev, NULL);
358	if (ret) {
359		struct acpi_bus_type *type = acpi_get_bus_type(dev);
360
361		if (!type)
362			goto err;
363
364		adev = type->find_companion(dev);
365		if (!adev) {
366			dev_dbg(dev, "ACPI companion not found\n");
367			goto err;
368		}
369		ret = acpi_bind_one(dev, adev);
370		if (ret)
371			goto err;
372
373		if (type->setup) {
374			type->setup(dev);
375			goto done;
376		}
377	} else {
378		adev = ACPI_COMPANION(dev);
379
380		if (dev_is_pci(dev)) {
381			pci_acpi_setup(dev, adev);
382			goto done;
383		} else if (dev_is_platform(dev)) {
384			acpi_configure_pmsi_domain(dev);
385		}
386	}
387
388	if (adev->handler && adev->handler->bind)
389		adev->handler->bind(dev);
390
391done:
392	acpi_handle_debug(ACPI_HANDLE(dev), "Bound to device %s\n",
393			  dev_name(dev));
394
395	return;
396
397err:
398	dev_dbg(dev, "No ACPI support\n");
399}
400
401void acpi_device_notify_remove(struct device *dev)
402{
403	struct acpi_device *adev = ACPI_COMPANION(dev);
404
405	if (!adev)
406		return;
407
408	if (dev_is_pci(dev))
409		pci_acpi_cleanup(dev, adev);
410	else if (adev->handler && adev->handler->unbind)
411		adev->handler->unbind(dev);
412
413	acpi_unbind_one(dev);
414}
415