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(sem: &bus_type_sem);
38 list_add_tail(new: &type->list, head: &bus_type_list);
39 up_write(sem: &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(sem: &bus_type_sem);
53 list_del_init(entry: &type->list);
54 up_write(sem: &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(sem: &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(sem: &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, fn: 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(handle: adev->handle, pathname: "_STA", NULL, data: &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(adev: wd->adev, check_children: 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, check_children: 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(adev: parent, fn: check_one_child, data: &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, check_sta: 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(parent: adev, address: adr, check_children: false, check_sta: 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(adev: 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(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(lock: &acpi_dev->physical_node_lock);
267
268 dev_warn(dev, "Already associated with ACPI node\n");
269 kfree(objp: physical_node);
270 if (ACPI_COMPANION(dev) != acpi_dev)
271 goto err;
272
273 put_device(dev);
274 acpi_dev_put(adev: 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(new: &physical_node->node, head: 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(buf: physical_node_name, node_id);
292 retval = sysfs_create_link(kobj: &acpi_dev->dev.kobj, target: &dev->kobj,
293 name: 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(kobj: &dev->kobj, target: &acpi_dev->dev.kobj,
299 name: "firmware_node");
300 if (retval)
301 dev_err(dev, "Failed to create link firmware_node (%d)\n",
302 retval);
303
304 mutex_unlock(lock: &acpi_dev->physical_node_lock);
305
306 if (acpi_dev->wakeup.flags.valid)
307 device_set_wakeup_capable(dev, capable: true);
308
309 return 0;
310
311 err:
312 ACPI_COMPANION_SET(dev, NULL);
313 put_device(dev);
314 acpi_dev_put(adev: 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(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: &entry->node);
334 acpi_dev->physical_node_count--;
335
336 acpi_physnode_link_name(buf: physnode_name, node_id: entry->node_id);
337 sysfs_remove_link(kobj: &acpi_dev->dev.kobj, name: physnode_name);
338 sysfs_remove_link(kobj: &dev->kobj, name: "firmware_node");
339 ACPI_COMPANION_SET(dev, NULL);
340 /* Drop references taken by acpi_bind_one(). */
341 put_device(dev);
342 acpi_dev_put(adev: acpi_dev);
343 kfree(objp: entry);
344 break;
345 }
346
347 mutex_unlock(lock: &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