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(new: &lookup->list, head: &drm_privacy_screen_lookup_list); |
59 | mutex_unlock(lock: &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(entry: &lookup->list); |
75 | mutex_unlock(lock: &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(dev: &priv->dev), name) == 0) { |
91 | dev = get_device(dev: &priv->dev); |
92 | break; |
93 | } |
94 | } |
95 | |
96 | mutex_unlock(lock: &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(lock: &drm_privacy_screen_lookup_lock); |
166 | |
167 | if (!provider) |
168 | return ERR_PTR(error: -ENODEV); |
169 | |
170 | priv = drm_privacy_screen_get_by_name(name: provider); |
171 | if (!priv) |
172 | return ERR_PTR(error: -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(ptr: priv)) |
189 | return; |
190 | |
191 | put_device(dev: &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(lock: &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(lock: &priv->lock); |
257 | } |
258 | EXPORT_SYMBOL(drm_privacy_screen_get_state); |
259 | |
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. |
272 | * A pointer to the drm_privacy_screen's struct is passed as the ``void *data`` |
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(nh: &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(nh: &priv->notifier_head, nb); |
300 | } |
301 | EXPORT_SYMBOL(drm_privacy_screen_unregister_notifier); |
302 | |
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, fmt: "%s\n" , sw_state_names[priv->sw_state]); |
323 | |
324 | mutex_unlock(lock: &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, fmt: "%s\n" , hw_state_names[priv->hw_state]); |
353 | |
354 | mutex_unlock(lock: &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(objp: 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 |
382 | * @data: Private data owned by the privacy screen provider |
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( |
391 | struct device *parent, const struct drm_privacy_screen_ops *ops, |
392 | void *data) |
393 | { |
394 | struct drm_privacy_screen *priv; |
395 | int ret; |
396 | |
397 | priv = kzalloc(size: sizeof(*priv), GFP_KERNEL); |
398 | if (!priv) |
399 | return ERR_PTR(error: -ENOMEM); |
400 | |
401 | mutex_init(&priv->lock); |
402 | BLOCKING_INIT_NOTIFIER_HEAD(&priv->notifier_head); |
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(dev: &priv->dev, name: "privacy_screen-%s" , dev_name(dev: parent)); |
409 | priv->drvdata = data; |
410 | priv->ops = ops; |
411 | |
412 | priv->ops->get_hw_state(priv); |
413 | |
414 | ret = device_register(dev: &priv->dev); |
415 | if (ret) { |
416 | put_device(dev: &priv->dev); |
417 | return ERR_PTR(error: ret); |
418 | } |
419 | |
420 | mutex_lock(&drm_privacy_screen_devs_lock); |
421 | list_add(new: &priv->list, head: &drm_privacy_screen_devs); |
422 | mutex_unlock(lock: &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(ptr: priv)) |
438 | return; |
439 | |
440 | mutex_lock(&drm_privacy_screen_devs_lock); |
441 | list_del(entry: &priv->list); |
442 | mutex_unlock(lock: &drm_privacy_screen_devs_lock); |
443 | |
444 | mutex_lock(&priv->lock); |
445 | priv->drvdata = NULL; |
446 | priv->ops = NULL; |
447 | mutex_unlock(lock: &priv->lock); |
448 | |
449 | device_unregister(dev: &priv->dev); |
450 | } |
451 | EXPORT_SYMBOL(drm_privacy_screen_unregister); |
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(nh: &priv->notifier_head, val: 0, v: priv); |
470 | } |
471 | EXPORT_SYMBOL(drm_privacy_screen_call_notifier_chain); |
472 | |