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a1a98689 HG |
1 | // SPDX-License-Identifier: MIT |
2 | /* | |
3 | * Copyright (C) 2020 - 2021 Red Hat, Inc. | |
4 | * | |
5 | * Authors: | |
6 | * Hans de Goede <hdegoede@redhat.com> | |
7 | */ | |
8 | ||
9 | #include <linux/device.h> | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/list.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/mutex.h> | |
14 | #include <linux/slab.h> | |
15 | #include <drm/drm_privacy_screen_machine.h> | |
16 | #include <drm/drm_privacy_screen_consumer.h> | |
17 | #include <drm/drm_privacy_screen_driver.h> | |
18 | #include "drm_internal.h" | |
19 | ||
20 | /** | |
21 | * DOC: overview | |
22 | * | |
23 | * This class allows non KMS drivers, from e.g. drivers/platform/x86 to | |
24 | * register a privacy-screen device, which the KMS drivers can then use | |
25 | * to implement the standard privacy-screen properties, see | |
26 | * :ref:`Standard Connector Properties<standard_connector_properties>`. | |
27 | * | |
28 | * KMS drivers using a privacy-screen class device are advised to use the | |
29 | * drm_connector_attach_privacy_screen_provider() and | |
30 | * drm_connector_update_privacy_screen() helpers for dealing with this. | |
31 | */ | |
32 | ||
33 | #define to_drm_privacy_screen(dev) \ | |
34 | container_of(dev, struct drm_privacy_screen, dev) | |
35 | ||
36 | static DEFINE_MUTEX(drm_privacy_screen_lookup_lock); | |
37 | static LIST_HEAD(drm_privacy_screen_lookup_list); | |
38 | ||
39 | static DEFINE_MUTEX(drm_privacy_screen_devs_lock); | |
40 | static LIST_HEAD(drm_privacy_screen_devs); | |
41 | ||
42 | /*** drm_privacy_screen_machine.h functions ***/ | |
43 | ||
44 | /** | |
45 | * drm_privacy_screen_lookup_add - add an entry to the static privacy-screen | |
46 | * lookup list | |
47 | * @lookup: lookup list entry to add | |
48 | * | |
49 | * Add an entry to the static privacy-screen lookup list. Note the | |
50 | * &struct list_head which is part of the &struct drm_privacy_screen_lookup | |
51 | * gets added to a list owned by the privacy-screen core. So the passed in | |
52 | * &struct drm_privacy_screen_lookup must not be free-ed until it is removed | |
53 | * from the lookup list by calling drm_privacy_screen_lookup_remove(). | |
54 | */ | |
55 | void drm_privacy_screen_lookup_add(struct drm_privacy_screen_lookup *lookup) | |
56 | { | |
57 | mutex_lock(&drm_privacy_screen_lookup_lock); | |
58 | list_add(&lookup->list, &drm_privacy_screen_lookup_list); | |
59 | mutex_unlock(&drm_privacy_screen_lookup_lock); | |
60 | } | |
61 | EXPORT_SYMBOL(drm_privacy_screen_lookup_add); | |
62 | ||
63 | /** | |
64 | * drm_privacy_screen_lookup_remove - remove an entry to the static | |
65 | * privacy-screen lookup list | |
66 | * @lookup: lookup list entry to remove | |
67 | * | |
68 | * Remove an entry previously added with drm_privacy_screen_lookup_add() | |
69 | * from the static privacy-screen lookup list. | |
70 | */ | |
71 | void drm_privacy_screen_lookup_remove(struct drm_privacy_screen_lookup *lookup) | |
72 | { | |
73 | mutex_lock(&drm_privacy_screen_lookup_lock); | |
74 | list_del(&lookup->list); | |
75 | mutex_unlock(&drm_privacy_screen_lookup_lock); | |
76 | } | |
77 | EXPORT_SYMBOL(drm_privacy_screen_lookup_remove); | |
78 | ||
79 | /*** drm_privacy_screen_consumer.h functions ***/ | |
80 | ||
81 | static struct drm_privacy_screen *drm_privacy_screen_get_by_name( | |
82 | const char *name) | |
83 | { | |
84 | struct drm_privacy_screen *priv; | |
85 | struct device *dev = NULL; | |
86 | ||
87 | mutex_lock(&drm_privacy_screen_devs_lock); | |
88 | ||
89 | list_for_each_entry(priv, &drm_privacy_screen_devs, list) { | |
90 | if (strcmp(dev_name(&priv->dev), name) == 0) { | |
91 | dev = get_device(&priv->dev); | |
92 | break; | |
93 | } | |
94 | } | |
95 | ||
96 | mutex_unlock(&drm_privacy_screen_devs_lock); | |
97 | ||
98 | return dev ? to_drm_privacy_screen(dev) : NULL; | |
99 | } | |
100 | ||
101 | /** | |
102 | * drm_privacy_screen_get - get a privacy-screen provider | |
103 | * @dev: consumer-device for which to get a privacy-screen provider | |
104 | * @con_id: (video)connector name for which to get a privacy-screen provider | |
105 | * | |
106 | * Get a privacy-screen provider for a privacy-screen attached to the | |
107 | * display described by the @dev and @con_id parameters. | |
108 | * | |
109 | * Return: | |
110 | * * A pointer to a &struct drm_privacy_screen on success. | |
111 | * * ERR_PTR(-ENODEV) if no matching privacy-screen is found | |
112 | * * ERR_PTR(-EPROBE_DEFER) if there is a matching privacy-screen, | |
113 | * but it has not been registered yet. | |
114 | */ | |
115 | struct drm_privacy_screen *drm_privacy_screen_get(struct device *dev, | |
116 | const char *con_id) | |
117 | { | |
118 | const char *dev_id = dev ? dev_name(dev) : NULL; | |
119 | struct drm_privacy_screen_lookup *l; | |
120 | struct drm_privacy_screen *priv; | |
121 | const char *provider = NULL; | |
122 | int match, best = -1; | |
123 | ||
124 | /* | |
125 | * For now we only support using a static lookup table, which is | |
126 | * populated by the drm_privacy_screen_arch_init() call. This should | |
127 | * be extended with device-tree / fw_node lookup when support is added | |
128 | * for device-tree using hardware with a privacy-screen. | |
129 | * | |
130 | * The lookup algorithm was shamelessly taken from the clock | |
131 | * framework: | |
132 | * | |
133 | * We do slightly fuzzy matching here: | |
134 | * An entry with a NULL ID is assumed to be a wildcard. | |
135 | * If an entry has a device ID, it must match | |
136 | * If an entry has a connection ID, it must match | |
137 | * Then we take the most specific entry - with the following order | |
138 | * of precedence: dev+con > dev only > con only. | |
139 | */ | |
140 | mutex_lock(&drm_privacy_screen_lookup_lock); | |
141 | ||
142 | list_for_each_entry(l, &drm_privacy_screen_lookup_list, list) { | |
143 | match = 0; | |
144 | ||
145 | if (l->dev_id) { | |
146 | if (!dev_id || strcmp(l->dev_id, dev_id)) | |
147 | continue; | |
148 | ||
149 | match += 2; | |
150 | } | |
151 | ||
152 | if (l->con_id) { | |
153 | if (!con_id || strcmp(l->con_id, con_id)) | |
154 | continue; | |
155 | ||
156 | match += 1; | |
157 | } | |
158 | ||
159 | if (match > best) { | |
160 | provider = l->provider; | |
161 | best = match; | |
162 | } | |
163 | } | |
164 | ||
165 | mutex_unlock(&drm_privacy_screen_lookup_lock); | |
166 | ||
167 | if (!provider) | |
168 | return ERR_PTR(-ENODEV); | |
169 | ||
170 | priv = drm_privacy_screen_get_by_name(provider); | |
171 | if (!priv) | |
172 | return ERR_PTR(-EPROBE_DEFER); | |
173 | ||
174 | return priv; | |
175 | } | |
176 | EXPORT_SYMBOL(drm_privacy_screen_get); | |
177 | ||
178 | /** | |
179 | * drm_privacy_screen_put - release a privacy-screen reference | |
180 | * @priv: privacy screen reference to release | |
181 | * | |
182 | * Release a privacy-screen provider reference gotten through | |
183 | * drm_privacy_screen_get(). May be called with a NULL or ERR_PTR, | |
184 | * in which case it is a no-op. | |
185 | */ | |
186 | void drm_privacy_screen_put(struct drm_privacy_screen *priv) | |
187 | { | |
188 | if (IS_ERR_OR_NULL(priv)) | |
189 | return; | |
190 | ||
191 | put_device(&priv->dev); | |
192 | } | |
193 | EXPORT_SYMBOL(drm_privacy_screen_put); | |
194 | ||
195 | /** | |
196 | * drm_privacy_screen_set_sw_state - set a privacy-screen's sw-state | |
197 | * @priv: privacy screen to set the sw-state for | |
198 | * @sw_state: new sw-state value to set | |
199 | * | |
200 | * Set the sw-state of a privacy screen. If the privacy-screen is not | |
201 | * in a locked hw-state, then the actual and hw-state of the privacy-screen | |
202 | * will be immediately updated to the new value. If the privacy-screen is | |
203 | * in a locked hw-state, then the new sw-state will be remembered as the | |
204 | * requested state to put the privacy-screen in when it becomes unlocked. | |
205 | * | |
206 | * Return: 0 on success, negative error code on failure. | |
207 | */ | |
208 | int drm_privacy_screen_set_sw_state(struct drm_privacy_screen *priv, | |
209 | enum drm_privacy_screen_status sw_state) | |
210 | { | |
211 | int ret = 0; | |
212 | ||
213 | mutex_lock(&priv->lock); | |
214 | ||
215 | if (!priv->ops) { | |
216 | ret = -ENODEV; | |
217 | goto out; | |
218 | } | |
219 | ||
220 | /* | |
221 | * As per the DRM connector properties documentation, setting the | |
222 | * sw_state while the hw_state is locked is allowed. In this case | |
223 | * it is a no-op other then storing the new sw_state so that it | |
224 | * can be honored when the state gets unlocked. | |
225 | * Also skip the set if the hw already is in the desired state. | |
226 | */ | |
227 | if (priv->hw_state >= PRIVACY_SCREEN_DISABLED_LOCKED || | |
228 | priv->hw_state == sw_state) { | |
229 | priv->sw_state = sw_state; | |
230 | goto out; | |
231 | } | |
232 | ||
233 | ret = priv->ops->set_sw_state(priv, sw_state); | |
234 | out: | |
235 | mutex_unlock(&priv->lock); | |
236 | return ret; | |
237 | } | |
238 | EXPORT_SYMBOL(drm_privacy_screen_set_sw_state); | |
239 | ||
240 | /** | |
241 | * drm_privacy_screen_get_state - get privacy-screen's current state | |
242 | * @priv: privacy screen to get the state for | |
243 | * @sw_state_ret: address where to store the privacy-screens current sw-state | |
244 | * @hw_state_ret: address where to store the privacy-screens current hw-state | |
245 | * | |
246 | * Get the current state of a privacy-screen, both the sw-state and the | |
247 | * hw-state. | |
248 | */ | |
249 | void drm_privacy_screen_get_state(struct drm_privacy_screen *priv, | |
250 | enum drm_privacy_screen_status *sw_state_ret, | |
251 | enum drm_privacy_screen_status *hw_state_ret) | |
252 | { | |
253 | mutex_lock(&priv->lock); | |
254 | *sw_state_ret = priv->sw_state; | |
255 | *hw_state_ret = priv->hw_state; | |
256 | mutex_unlock(&priv->lock); | |
257 | } | |
258 | EXPORT_SYMBOL(drm_privacy_screen_get_state); | |
259 | ||
8a12b170 HG |
260 | /** |
261 | * drm_privacy_screen_register_notifier - register a notifier | |
262 | * @priv: Privacy screen to register the notifier with | |
263 | * @nb: Notifier-block for the notifier to register | |
264 | * | |
265 | * Register a notifier with the privacy-screen to be notified of changes made | |
266 | * to the privacy-screen state from outside of the privacy-screen class. | |
267 | * E.g. the state may be changed by the hardware itself in response to a | |
268 | * hotkey press. | |
269 | * | |
270 | * The notifier is called with no locks held. The new hw_state and sw_state | |
271 | * can be retrieved using the drm_privacy_screen_get_state() function. | |
200e8e3e | 272 | * A pointer to the drm_privacy_screen's struct is passed as the ``void *data`` |
8a12b170 HG |
273 | * argument of the notifier_block's notifier_call. |
274 | * | |
275 | * The notifier will NOT be called when changes are made through | |
276 | * drm_privacy_screen_set_sw_state(). It is only called for external changes. | |
277 | * | |
278 | * Return: 0 on success, negative error code on failure. | |
279 | */ | |
280 | int drm_privacy_screen_register_notifier(struct drm_privacy_screen *priv, | |
281 | struct notifier_block *nb) | |
282 | { | |
283 | return blocking_notifier_chain_register(&priv->notifier_head, nb); | |
284 | } | |
285 | EXPORT_SYMBOL(drm_privacy_screen_register_notifier); | |
286 | ||
287 | /** | |
288 | * drm_privacy_screen_unregister_notifier - unregister a notifier | |
289 | * @priv: Privacy screen to register the notifier with | |
290 | * @nb: Notifier-block for the notifier to register | |
291 | * | |
292 | * Unregister a notifier registered with drm_privacy_screen_register_notifier(). | |
293 | * | |
294 | * Return: 0 on success, negative error code on failure. | |
295 | */ | |
296 | int drm_privacy_screen_unregister_notifier(struct drm_privacy_screen *priv, | |
297 | struct notifier_block *nb) | |
298 | { | |
299 | return blocking_notifier_chain_unregister(&priv->notifier_head, nb); | |
300 | } | |
301 | EXPORT_SYMBOL(drm_privacy_screen_unregister_notifier); | |
302 | ||
a1a98689 HG |
303 | /*** drm_privacy_screen_driver.h functions ***/ |
304 | ||
305 | static ssize_t sw_state_show(struct device *dev, | |
306 | struct device_attribute *attr, char *buf) | |
307 | { | |
308 | struct drm_privacy_screen *priv = to_drm_privacy_screen(dev); | |
309 | const char * const sw_state_names[] = { | |
310 | "Disabled", | |
311 | "Enabled", | |
312 | }; | |
313 | ssize_t ret; | |
314 | ||
315 | mutex_lock(&priv->lock); | |
316 | ||
317 | if (!priv->ops) | |
318 | ret = -ENODEV; | |
319 | else if (WARN_ON(priv->sw_state >= ARRAY_SIZE(sw_state_names))) | |
320 | ret = -ENXIO; | |
321 | else | |
322 | ret = sprintf(buf, "%s\n", sw_state_names[priv->sw_state]); | |
323 | ||
324 | mutex_unlock(&priv->lock); | |
325 | return ret; | |
326 | } | |
327 | /* | |
328 | * RO: Do not allow setting the sw_state through sysfs, this MUST be done | |
329 | * through the drm_properties on the drm_connector. | |
330 | */ | |
331 | static DEVICE_ATTR_RO(sw_state); | |
332 | ||
333 | static ssize_t hw_state_show(struct device *dev, | |
334 | struct device_attribute *attr, char *buf) | |
335 | { | |
336 | struct drm_privacy_screen *priv = to_drm_privacy_screen(dev); | |
337 | const char * const hw_state_names[] = { | |
338 | "Disabled", | |
339 | "Enabled", | |
340 | "Disabled, locked", | |
341 | "Enabled, locked", | |
342 | }; | |
343 | ssize_t ret; | |
344 | ||
345 | mutex_lock(&priv->lock); | |
346 | ||
347 | if (!priv->ops) | |
348 | ret = -ENODEV; | |
349 | else if (WARN_ON(priv->hw_state >= ARRAY_SIZE(hw_state_names))) | |
350 | ret = -ENXIO; | |
351 | else | |
352 | ret = sprintf(buf, "%s\n", hw_state_names[priv->hw_state]); | |
353 | ||
354 | mutex_unlock(&priv->lock); | |
355 | return ret; | |
356 | } | |
357 | static DEVICE_ATTR_RO(hw_state); | |
358 | ||
359 | static struct attribute *drm_privacy_screen_attrs[] = { | |
360 | &dev_attr_sw_state.attr, | |
361 | &dev_attr_hw_state.attr, | |
362 | NULL | |
363 | }; | |
364 | ATTRIBUTE_GROUPS(drm_privacy_screen); | |
365 | ||
366 | static struct device_type drm_privacy_screen_type = { | |
367 | .name = "privacy_screen", | |
368 | .groups = drm_privacy_screen_groups, | |
369 | }; | |
370 | ||
371 | static void drm_privacy_screen_device_release(struct device *dev) | |
372 | { | |
373 | struct drm_privacy_screen *priv = to_drm_privacy_screen(dev); | |
374 | ||
375 | kfree(priv); | |
376 | } | |
377 | ||
378 | /** | |
379 | * drm_privacy_screen_register - register a privacy-screen | |
380 | * @parent: parent-device for the privacy-screen | |
381 | * @ops: &struct drm_privacy_screen_ops pointer with ops for the privacy-screen | |
ccbeca4c | 382 | * @data: Private data owned by the privacy screen provider |
a1a98689 HG |
383 | * |
384 | * Create and register a privacy-screen. | |
385 | * | |
386 | * Return: | |
387 | * * A pointer to the created privacy-screen on success. | |
388 | * * An ERR_PTR(errno) on failure. | |
389 | */ | |
390 | struct drm_privacy_screen *drm_privacy_screen_register( | |
30598d92 RJ |
391 | struct device *parent, const struct drm_privacy_screen_ops *ops, |
392 | void *data) | |
a1a98689 HG |
393 | { |
394 | struct drm_privacy_screen *priv; | |
395 | int ret; | |
396 | ||
397 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
398 | if (!priv) | |
399 | return ERR_PTR(-ENOMEM); | |
400 | ||
401 | mutex_init(&priv->lock); | |
8a12b170 | 402 | BLOCKING_INIT_NOTIFIER_HEAD(&priv->notifier_head); |
a1a98689 HG |
403 | |
404 | priv->dev.class = drm_class; | |
405 | priv->dev.type = &drm_privacy_screen_type; | |
406 | priv->dev.parent = parent; | |
407 | priv->dev.release = drm_privacy_screen_device_release; | |
408 | dev_set_name(&priv->dev, "privacy_screen-%s", dev_name(parent)); | |
30598d92 | 409 | priv->drvdata = data; |
a1a98689 HG |
410 | priv->ops = ops; |
411 | ||
412 | priv->ops->get_hw_state(priv); | |
413 | ||
414 | ret = device_register(&priv->dev); | |
415 | if (ret) { | |
416 | put_device(&priv->dev); | |
417 | return ERR_PTR(ret); | |
418 | } | |
419 | ||
420 | mutex_lock(&drm_privacy_screen_devs_lock); | |
421 | list_add(&priv->list, &drm_privacy_screen_devs); | |
422 | mutex_unlock(&drm_privacy_screen_devs_lock); | |
423 | ||
424 | return priv; | |
425 | } | |
426 | EXPORT_SYMBOL(drm_privacy_screen_register); | |
427 | ||
428 | /** | |
429 | * drm_privacy_screen_unregister - unregister privacy-screen | |
430 | * @priv: privacy-screen to unregister | |
431 | * | |
432 | * Unregister a privacy-screen registered with drm_privacy_screen_register(). | |
433 | * May be called with a NULL or ERR_PTR, in which case it is a no-op. | |
434 | */ | |
435 | void drm_privacy_screen_unregister(struct drm_privacy_screen *priv) | |
436 | { | |
437 | if (IS_ERR_OR_NULL(priv)) | |
438 | return; | |
439 | ||
440 | mutex_lock(&drm_privacy_screen_devs_lock); | |
441 | list_del(&priv->list); | |
442 | mutex_unlock(&drm_privacy_screen_devs_lock); | |
443 | ||
444 | mutex_lock(&priv->lock); | |
30598d92 | 445 | priv->drvdata = NULL; |
a1a98689 HG |
446 | priv->ops = NULL; |
447 | mutex_unlock(&priv->lock); | |
448 | ||
449 | device_unregister(&priv->dev); | |
450 | } | |
451 | EXPORT_SYMBOL(drm_privacy_screen_unregister); | |
8a12b170 HG |
452 | |
453 | /** | |
454 | * drm_privacy_screen_call_notifier_chain - notify consumers of state change | |
455 | * @priv: Privacy screen to register the notifier with | |
456 | * | |
457 | * A privacy-screen provider driver can call this functions upon external | |
458 | * changes to the privacy-screen state. E.g. the state may be changed by the | |
459 | * hardware itself in response to a hotkey press. | |
460 | * This function must be called without holding the privacy-screen lock. | |
461 | * the driver must update sw_state and hw_state to reflect the new state before | |
462 | * calling this function. | |
463 | * The expected behavior from the driver upon receiving an external state | |
464 | * change event is: 1. Take the lock; 2. Update sw_state and hw_state; | |
465 | * 3. Release the lock. 4. Call drm_privacy_screen_call_notifier_chain(). | |
466 | */ | |
467 | void drm_privacy_screen_call_notifier_chain(struct drm_privacy_screen *priv) | |
468 | { | |
469 | blocking_notifier_call_chain(&priv->notifier_head, 0, priv); | |
470 | } | |
471 | EXPORT_SYMBOL(drm_privacy_screen_call_notifier_chain); |