1/*
  2 * Copyright (c) 2014 Samsung Electronics Co., Ltd
  3 *
  4 * Permission is hereby granted, free of charge, to any person obtaining a
  5 * copy of this software and associated documentation files (the "Software"),
  6 * to deal in the Software without restriction, including without limitation
  7 * the rights to use, copy, modify, merge, publish, distribute, sub license,
  8 * and/or sell copies of the Software, and to permit persons to whom the
  9 * Software is furnished to do so, subject to the following conditions:
 10 *
 11 * The above copyright notice and this permission notice (including the
 12 * next paragraph) shall be included in all copies or substantial portions
 13 * of the Software.
 14 *
 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 21 * DEALINGS IN THE SOFTWARE.
 22 */
 23
 24#include <linux/err.h>
 25#include <linux/module.h>
 26#include <linux/mutex.h>
 27
 28#include <drm/drm_bridge.h>
 29#include <drm/drm_encoder.h>
 30
 31#include "drm_crtc_internal.h"
 32
 33/**
 34 * DOC: overview
 35 *
 36 * &struct drm_bridge represents a device that hangs on to an encoder. These are
 37 * handy when a regular &drm_encoder entity isn't enough to represent the entire
 38 * encoder chain.
 39 *
 40 * A bridge is always attached to a single &drm_encoder at a time, but can be
 41 * either connected to it directly, or through an intermediate bridge::
 42 *
 43 *     encoder ---> bridge B ---> bridge A
 44 *
 45 * Here, the output of the encoder feeds to bridge B, and that furthers feeds to
 46 * bridge A.
 47 *
 48 * The driver using the bridge is responsible to make the associations between
 49 * the encoder and bridges. Once these links are made, the bridges will
 50 * participate along with encoder functions to perform mode_set/enable/disable
 51 * through the ops provided in &drm_bridge_funcs.
 52 *
 53 * drm_bridge, like drm_panel, aren't drm_mode_object entities like planes,
 54 * CRTCs, encoders or connectors and hence are not visible to userspace. They
 55 * just provide additional hooks to get the desired output at the end of the
 56 * encoder chain.
 57 *
 58 * Bridges can also be chained up using the &drm_bridge.next pointer.
 59 *
 60 * Both legacy CRTC helpers and the new atomic modeset helpers support bridges.
 61 */
 62
 63static DEFINE_MUTEX(bridge_lock);
 64static LIST_HEAD(bridge_list);
 65
 66/**
 67 * drm_bridge_add - add the given bridge to the global bridge list
 68 *
 69 * @bridge: bridge control structure
 70 */
 71void drm_bridge_add(struct drm_bridge *bridge)
 72{
 73	mutex_lock(&bridge_lock);
 74	list_add_tail(&bridge->list, &bridge_list);
 75	mutex_unlock(&bridge_lock);
 76}
 77EXPORT_SYMBOL(drm_bridge_add);
 78
 79/**
 80 * drm_bridge_remove - remove the given bridge from the global bridge list
 81 *
 82 * @bridge: bridge control structure
 83 */
 84void drm_bridge_remove(struct drm_bridge *bridge)
 85{
 86	mutex_lock(&bridge_lock);
 87	list_del_init(&bridge->list);
 88	mutex_unlock(&bridge_lock);
 89}
 90EXPORT_SYMBOL(drm_bridge_remove);
 91
 92/**
 93 * drm_bridge_attach - attach the bridge to an encoder's chain
 94 *
 95 * @encoder: DRM encoder
 96 * @bridge: bridge to attach
 97 * @previous: previous bridge in the chain (optional)
 98 *
 99 * Called by a kms driver to link the bridge to an encoder's chain. The previous
100 * argument specifies the previous bridge in the chain. If NULL, the bridge is
101 * linked directly at the encoder's output. Otherwise it is linked at the
102 * previous bridge's output.
103 *
104 * If non-NULL the previous bridge must be already attached by a call to this
105 * function.
106 *
107 * Note that bridges attached to encoders are auto-detached during encoder
108 * cleanup in drm_encoder_cleanup(), so drm_bridge_attach() should generally
109 * *not* be balanced with a drm_bridge_detach() in driver code.
110 *
111 * RETURNS:
112 * Zero on success, error code on failure
113 */
114int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
115		      struct drm_bridge *previous)
116{
117	int ret;
118
119	if (!encoder || !bridge)
120		return -EINVAL;
121
122	if (previous && (!previous->dev || previous->encoder != encoder))
123		return -EINVAL;
124
125	if (bridge->dev)
126		return -EBUSY;
127
128	bridge->dev = encoder->dev;
129	bridge->encoder = encoder;
130
131	if (bridge->funcs->attach) {
132		ret = bridge->funcs->attach(bridge);
133		if (ret < 0) {
134			bridge->dev = NULL;
135			bridge->encoder = NULL;
136			return ret;
137		}
138	}
139
140	if (previous)
141		previous->next = bridge;
142	else
143		encoder->bridge = bridge;
144
145	return 0;
146}
147EXPORT_SYMBOL(drm_bridge_attach);
148
149void drm_bridge_detach(struct drm_bridge *bridge)
150{
151	if (WARN_ON(!bridge))
152		return;
153
154	if (WARN_ON(!bridge->dev))
155		return;
156
157	if (bridge->funcs->detach)
158		bridge->funcs->detach(bridge);
159
160	bridge->dev = NULL;
161}
162
163/**
164 * DOC: bridge callbacks
165 *
166 * The &drm_bridge_funcs ops are populated by the bridge driver. The DRM
167 * internals (atomic and CRTC helpers) use the helpers defined in drm_bridge.c
168 * These helpers call a specific &drm_bridge_funcs op for all the bridges
169 * during encoder configuration.
170 *
171 * For detailed specification of the bridge callbacks see &drm_bridge_funcs.
172 */
173
174/**
175 * drm_bridge_mode_fixup - fixup proposed mode for all bridges in the
176 *			   encoder chain
177 * @bridge: bridge control structure
178 * @mode: desired mode to be set for the bridge
179 * @adjusted_mode: updated mode that works for this bridge
180 *
181 * Calls &drm_bridge_funcs.mode_fixup for all the bridges in the
182 * encoder chain, starting from the first bridge to the last.
183 *
184 * Note: the bridge passed should be the one closest to the encoder
185 *
186 * RETURNS:
187 * true on success, false on failure
188 */
189bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
190			const struct drm_display_mode *mode,
191			struct drm_display_mode *adjusted_mode)
192{
193	bool ret = true;
194
195	if (!bridge)
196		return true;
197
198	if (bridge->funcs->mode_fixup)
199		ret = bridge->funcs->mode_fixup(bridge, mode, adjusted_mode);
200
201	ret = ret && drm_bridge_mode_fixup(bridge->next, mode, adjusted_mode);
202
203	return ret;
204}
205EXPORT_SYMBOL(drm_bridge_mode_fixup);
206
207/**
208 * drm_bridge_mode_valid - validate the mode against all bridges in the
209 * 			   encoder chain.
210 * @bridge: bridge control structure
211 * @mode: desired mode to be validated
212 *
213 * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
214 * chain, starting from the first bridge to the last. If at least one bridge
215 * does not accept the mode the function returns the error code.
216 *
217 * Note: the bridge passed should be the one closest to the encoder.
218 *
219 * RETURNS:
220 * MODE_OK on success, drm_mode_status Enum error code on failure
221 */
222enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
223					   const struct drm_display_mode *mode)
224{
225	enum drm_mode_status ret = MODE_OK;
226
227	if (!bridge)
228		return ret;
229
230	if (bridge->funcs->mode_valid)
231		ret = bridge->funcs->mode_valid(bridge, mode);
232
233	if (ret != MODE_OK)
234		return ret;
235
236	return drm_bridge_mode_valid(bridge->next, mode);
237}
238EXPORT_SYMBOL(drm_bridge_mode_valid);
239
240/**
241 * drm_bridge_disable - disables all bridges in the encoder chain
242 * @bridge: bridge control structure
243 *
244 * Calls &drm_bridge_funcs.disable op for all the bridges in the encoder
245 * chain, starting from the last bridge to the first. These are called before
246 * calling the encoder's prepare op.
247 *
248 * Note: the bridge passed should be the one closest to the encoder
249 */
250void drm_bridge_disable(struct drm_bridge *bridge)
251{
252	if (!bridge)
253		return;
254
255	drm_bridge_disable(bridge->next);
256
257	if (bridge->funcs->disable)
258		bridge->funcs->disable(bridge);
259}
260EXPORT_SYMBOL(drm_bridge_disable);
261
262/**
263 * drm_bridge_post_disable - cleans up after disabling all bridges in the encoder chain
264 * @bridge: bridge control structure
265 *
266 * Calls &drm_bridge_funcs.post_disable op for all the bridges in the
267 * encoder chain, starting from the first bridge to the last. These are called
268 * after completing the encoder's prepare op.
269 *
270 * Note: the bridge passed should be the one closest to the encoder
271 */
272void drm_bridge_post_disable(struct drm_bridge *bridge)
273{
274	if (!bridge)
275		return;
276
277	if (bridge->funcs->post_disable)
278		bridge->funcs->post_disable(bridge);
279
280	drm_bridge_post_disable(bridge->next);
281}
282EXPORT_SYMBOL(drm_bridge_post_disable);
283
284/**
285 * drm_bridge_mode_set - set proposed mode for all bridges in the
286 *			 encoder chain
287 * @bridge: bridge control structure
288 * @mode: desired mode to be set for the bridge
289 * @adjusted_mode: updated mode that works for this bridge
290 *
291 * Calls &drm_bridge_funcs.mode_set op for all the bridges in the
292 * encoder chain, starting from the first bridge to the last.
293 *
294 * Note: the bridge passed should be the one closest to the encoder
295 */
296void drm_bridge_mode_set(struct drm_bridge *bridge,
297			 const struct drm_display_mode *mode,
298			 const struct drm_display_mode *adjusted_mode)
299{
300	if (!bridge)
301		return;
302
303	if (bridge->funcs->mode_set)
304		bridge->funcs->mode_set(bridge, mode, adjusted_mode);
305
306	drm_bridge_mode_set(bridge->next, mode, adjusted_mode);
307}
308EXPORT_SYMBOL(drm_bridge_mode_set);
309
310/**
311 * drm_bridge_pre_enable - prepares for enabling all
312 *			   bridges in the encoder chain
313 * @bridge: bridge control structure
314 *
315 * Calls &drm_bridge_funcs.pre_enable op for all the bridges in the encoder
316 * chain, starting from the last bridge to the first. These are called
317 * before calling the encoder's commit op.
318 *
319 * Note: the bridge passed should be the one closest to the encoder
320 */
321void drm_bridge_pre_enable(struct drm_bridge *bridge)
322{
323	if (!bridge)
324		return;
325
326	drm_bridge_pre_enable(bridge->next);
327
328	if (bridge->funcs->pre_enable)
329		bridge->funcs->pre_enable(bridge);
330}
331EXPORT_SYMBOL(drm_bridge_pre_enable);
332
333/**
334 * drm_bridge_enable - enables all bridges in the encoder chain
335 * @bridge: bridge control structure
336 *
337 * Calls &drm_bridge_funcs.enable op for all the bridges in the encoder
338 * chain, starting from the first bridge to the last. These are called
339 * after completing the encoder's commit op.
340 *
341 * Note that the bridge passed should be the one closest to the encoder
342 */
343void drm_bridge_enable(struct drm_bridge *bridge)
344{
345	if (!bridge)
346		return;
347
348	if (bridge->funcs->enable)
349		bridge->funcs->enable(bridge);
350
351	drm_bridge_enable(bridge->next);
352}
353EXPORT_SYMBOL(drm_bridge_enable);
354
355/**
356 * drm_atomic_bridge_disable - disables all bridges in the encoder chain
357 * @bridge: bridge control structure
358 * @state: atomic state being committed
359 *
360 * Calls &drm_bridge_funcs.atomic_disable (falls back on
361 * &drm_bridge_funcs.disable) op for all the bridges in the encoder chain,
362 * starting from the last bridge to the first. These are called before calling
363 * &drm_encoder_helper_funcs.atomic_disable
364 *
365 * Note: the bridge passed should be the one closest to the encoder
366 */
367void drm_atomic_bridge_disable(struct drm_bridge *bridge,
368			       struct drm_atomic_state *state)
369{
370	if (!bridge)
371		return;
372
373	drm_atomic_bridge_disable(bridge->next, state);
374
375	if (bridge->funcs->atomic_disable)
376		bridge->funcs->atomic_disable(bridge, state);
377	else if (bridge->funcs->disable)
378		bridge->funcs->disable(bridge);
379}
380EXPORT_SYMBOL(drm_atomic_bridge_disable);
381
382/**
383 * drm_atomic_bridge_post_disable - cleans up after disabling all bridges in the
384 *				    encoder chain
385 * @bridge: bridge control structure
386 * @state: atomic state being committed
387 *
388 * Calls &drm_bridge_funcs.atomic_post_disable (falls back on
389 * &drm_bridge_funcs.post_disable) op for all the bridges in the encoder chain,
390 * starting from the first bridge to the last. These are called after completing
391 * &drm_encoder_helper_funcs.atomic_disable
392 *
393 * Note: the bridge passed should be the one closest to the encoder
394 */
395void drm_atomic_bridge_post_disable(struct drm_bridge *bridge,
396				    struct drm_atomic_state *state)
397{
398	if (!bridge)
399		return;
400
401	if (bridge->funcs->atomic_post_disable)
402		bridge->funcs->atomic_post_disable(bridge, state);
403	else if (bridge->funcs->post_disable)
404		bridge->funcs->post_disable(bridge);
405
406	drm_atomic_bridge_post_disable(bridge->next, state);
407}
408EXPORT_SYMBOL(drm_atomic_bridge_post_disable);
409
410/**
411 * drm_atomic_bridge_pre_enable - prepares for enabling all bridges in the
412 *				  encoder chain
413 * @bridge: bridge control structure
414 * @state: atomic state being committed
415 *
416 * Calls &drm_bridge_funcs.atomic_pre_enable (falls back on
417 * &drm_bridge_funcs.pre_enable) op for all the bridges in the encoder chain,
418 * starting from the last bridge to the first. These are called before calling
419 * &drm_encoder_helper_funcs.atomic_enable
420 *
421 * Note: the bridge passed should be the one closest to the encoder
422 */
423void drm_atomic_bridge_pre_enable(struct drm_bridge *bridge,
424				  struct drm_atomic_state *state)
425{
426	if (!bridge)
427		return;
428
429	drm_atomic_bridge_pre_enable(bridge->next, state);
430
431	if (bridge->funcs->atomic_pre_enable)
432		bridge->funcs->atomic_pre_enable(bridge, state);
433	else if (bridge->funcs->pre_enable)
434		bridge->funcs->pre_enable(bridge);
435}
436EXPORT_SYMBOL(drm_atomic_bridge_pre_enable);
437
438/**
439 * drm_atomic_bridge_enable - enables all bridges in the encoder chain
440 * @bridge: bridge control structure
441 * @state: atomic state being committed
442 *
443 * Calls &drm_bridge_funcs.atomic_enable (falls back on
444 * &drm_bridge_funcs.enable) op for all the bridges in the encoder chain,
445 * starting from the first bridge to the last. These are called after completing
446 * &drm_encoder_helper_funcs.atomic_enable
447 *
448 * Note: the bridge passed should be the one closest to the encoder
449 */
450void drm_atomic_bridge_enable(struct drm_bridge *bridge,
451			      struct drm_atomic_state *state)
452{
453	if (!bridge)
454		return;
455
456	if (bridge->funcs->atomic_enable)
457		bridge->funcs->atomic_enable(bridge, state);
458	else if (bridge->funcs->enable)
459		bridge->funcs->enable(bridge);
460
461	drm_atomic_bridge_enable(bridge->next, state);
462}
463EXPORT_SYMBOL(drm_atomic_bridge_enable);
464
465#ifdef CONFIG_OF
466/**
467 * of_drm_find_bridge - find the bridge corresponding to the device node in
468 *			the global bridge list
469 *
470 * @np: device node
471 *
472 * RETURNS:
473 * drm_bridge control struct on success, NULL on failure
474 */
475struct drm_bridge *of_drm_find_bridge(struct device_node *np)
476{
477	struct drm_bridge *bridge;
478
479	mutex_lock(&bridge_lock);
480
481	list_for_each_entry(bridge, &bridge_list, list) {
482		if (bridge->of_node == np) {
483			mutex_unlock(&bridge_lock);
484			return bridge;
485		}
486	}
487
488	mutex_unlock(&bridge_lock);
489	return NULL;
490}
491EXPORT_SYMBOL(of_drm_find_bridge);
492#endif
493
494MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
495MODULE_DESCRIPTION("DRM bridge infrastructure");
496MODULE_LICENSE("GPL and additional rights");