Line data Source code
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/media-bus-format.h>
26 : #include <linux/module.h>
27 : #include <linux/mutex.h>
28 :
29 : #include <drm/drm_atomic_state_helper.h>
30 : #include <drm/drm_bridge.h>
31 : #include <drm/drm_encoder.h>
32 : #include <drm/drm_of.h>
33 : #include <drm/drm_print.h>
34 :
35 : #include "drm_crtc_internal.h"
36 :
37 : /**
38 : * DOC: overview
39 : *
40 : * &struct drm_bridge represents a device that hangs on to an encoder. These are
41 : * handy when a regular &drm_encoder entity isn't enough to represent the entire
42 : * encoder chain.
43 : *
44 : * A bridge is always attached to a single &drm_encoder at a time, but can be
45 : * either connected to it directly, or through a chain of bridges::
46 : *
47 : * [ CRTC ---> ] Encoder ---> Bridge A ---> Bridge B
48 : *
49 : * Here, the output of the encoder feeds to bridge A, and that furthers feeds to
50 : * bridge B. Bridge chains can be arbitrarily long, and shall be fully linear:
51 : * Chaining multiple bridges to the output of a bridge, or the same bridge to
52 : * the output of different bridges, is not supported.
53 : *
54 : * &drm_bridge, like &drm_panel, aren't &drm_mode_object entities like planes,
55 : * CRTCs, encoders or connectors and hence are not visible to userspace. They
56 : * just provide additional hooks to get the desired output at the end of the
57 : * encoder chain.
58 : */
59 :
60 : /**
61 : * DOC: display driver integration
62 : *
63 : * Display drivers are responsible for linking encoders with the first bridge
64 : * in the chains. This is done by acquiring the appropriate bridge with
65 : * devm_drm_of_get_bridge(). Once acquired, the bridge shall be attached to the
66 : * encoder with a call to drm_bridge_attach().
67 : *
68 : * Bridges are responsible for linking themselves with the next bridge in the
69 : * chain, if any. This is done the same way as for encoders, with the call to
70 : * drm_bridge_attach() occurring in the &drm_bridge_funcs.attach operation.
71 : *
72 : * Once these links are created, the bridges can participate along with encoder
73 : * functions to perform mode validation and fixup (through
74 : * drm_bridge_chain_mode_valid() and drm_atomic_bridge_chain_check()), mode
75 : * setting (through drm_bridge_chain_mode_set()), enable (through
76 : * drm_atomic_bridge_chain_pre_enable() and drm_atomic_bridge_chain_enable())
77 : * and disable (through drm_atomic_bridge_chain_disable() and
78 : * drm_atomic_bridge_chain_post_disable()). Those functions call the
79 : * corresponding operations provided in &drm_bridge_funcs in sequence for all
80 : * bridges in the chain.
81 : *
82 : * For display drivers that use the atomic helpers
83 : * drm_atomic_helper_check_modeset(),
84 : * drm_atomic_helper_commit_modeset_enables() and
85 : * drm_atomic_helper_commit_modeset_disables() (either directly in hand-rolled
86 : * commit check and commit tail handlers, or through the higher-level
87 : * drm_atomic_helper_check() and drm_atomic_helper_commit_tail() or
88 : * drm_atomic_helper_commit_tail_rpm() helpers), this is done transparently and
89 : * requires no intervention from the driver. For other drivers, the relevant
90 : * DRM bridge chain functions shall be called manually.
91 : *
92 : * Bridges also participate in implementing the &drm_connector at the end of
93 : * the bridge chain. Display drivers may use the drm_bridge_connector_init()
94 : * helper to create the &drm_connector, or implement it manually on top of the
95 : * connector-related operations exposed by the bridge (see the overview
96 : * documentation of bridge operations for more details).
97 : */
98 :
99 : /**
100 : * DOC: special care dsi
101 : *
102 : * The interaction between the bridges and other frameworks involved in
103 : * the probing of the upstream driver and the bridge driver can be
104 : * challenging. Indeed, there's multiple cases that needs to be
105 : * considered:
106 : *
107 : * - The upstream driver doesn't use the component framework and isn't a
108 : * MIPI-DSI host. In this case, the bridge driver will probe at some
109 : * point and the upstream driver should try to probe again by returning
110 : * EPROBE_DEFER as long as the bridge driver hasn't probed.
111 : *
112 : * - The upstream driver doesn't use the component framework, but is a
113 : * MIPI-DSI host. The bridge device uses the MIPI-DCS commands to be
114 : * controlled. In this case, the bridge device is a child of the
115 : * display device and when it will probe it's assured that the display
116 : * device (and MIPI-DSI host) is present. The upstream driver will be
117 : * assured that the bridge driver is connected between the
118 : * &mipi_dsi_host_ops.attach and &mipi_dsi_host_ops.detach operations.
119 : * Therefore, it must run mipi_dsi_host_register() in its probe
120 : * function, and then run drm_bridge_attach() in its
121 : * &mipi_dsi_host_ops.attach hook.
122 : *
123 : * - The upstream driver uses the component framework and is a MIPI-DSI
124 : * host. The bridge device uses the MIPI-DCS commands to be
125 : * controlled. This is the same situation than above, and can run
126 : * mipi_dsi_host_register() in either its probe or bind hooks.
127 : *
128 : * - The upstream driver uses the component framework and is a MIPI-DSI
129 : * host. The bridge device uses a separate bus (such as I2C) to be
130 : * controlled. In this case, there's no correlation between the probe
131 : * of the bridge and upstream drivers, so care must be taken to avoid
132 : * an endless EPROBE_DEFER loop, with each driver waiting for the
133 : * other to probe.
134 : *
135 : * The ideal pattern to cover the last item (and all the others in the
136 : * MIPI-DSI host driver case) is to split the operations like this:
137 : *
138 : * - The MIPI-DSI host driver must run mipi_dsi_host_register() in its
139 : * probe hook. It will make sure that the MIPI-DSI host sticks around,
140 : * and that the driver's bind can be called.
141 : *
142 : * - In its probe hook, the bridge driver must try to find its MIPI-DSI
143 : * host, register as a MIPI-DSI device and attach the MIPI-DSI device
144 : * to its host. The bridge driver is now functional.
145 : *
146 : * - In its &struct mipi_dsi_host_ops.attach hook, the MIPI-DSI host can
147 : * now add its component. Its bind hook will now be called and since
148 : * the bridge driver is attached and registered, we can now look for
149 : * and attach it.
150 : *
151 : * At this point, we're now certain that both the upstream driver and
152 : * the bridge driver are functional and we can't have a deadlock-like
153 : * situation when probing.
154 : */
155 :
156 : /**
157 : * DOC: dsi bridge operations
158 : *
159 : * DSI host interfaces are expected to be implemented as bridges rather than
160 : * encoders, however there are a few aspects of their operation that need to
161 : * be defined in order to provide a consistent interface.
162 : *
163 : * A DSI host should keep the PHY powered down until the pre_enable operation is
164 : * called. All lanes are in an undefined idle state up to this point, and it
165 : * must not be assumed that it is LP-11.
166 : * pre_enable should initialise the PHY, set the data lanes to LP-11, and the
167 : * clock lane to either LP-11 or HS depending on the mode_flag
168 : * %MIPI_DSI_CLOCK_NON_CONTINUOUS.
169 : *
170 : * Ordinarily the downstream bridge DSI peripheral pre_enable will have been
171 : * called before the DSI host. If the DSI peripheral requires LP-11 and/or
172 : * the clock lane to be in HS mode prior to pre_enable, then it can set the
173 : * &pre_enable_prev_first flag to request the pre_enable (and
174 : * post_disable) order to be altered to enable the DSI host first.
175 : *
176 : * Either the CRTC being enabled, or the DSI host enable operation should switch
177 : * the host to actively transmitting video on the data lanes.
178 : *
179 : * The reverse also applies. The DSI host disable operation or stopping the CRTC
180 : * should stop transmitting video, and the data lanes should return to the LP-11
181 : * state. The DSI host &post_disable operation should disable the PHY.
182 : * If the &pre_enable_prev_first flag is set, then the DSI peripheral's
183 : * bridge &post_disable will be called before the DSI host's post_disable.
184 : *
185 : * Whilst it is valid to call &host_transfer prior to pre_enable or after
186 : * post_disable, the exact state of the lanes is undefined at this point. The
187 : * DSI host should initialise the interface, transmit the data, and then disable
188 : * the interface again.
189 : *
190 : * Ultra Low Power State (ULPS) is not explicitly supported by DRM. If
191 : * implemented, it therefore needs to be handled entirely within the DSI Host
192 : * driver.
193 : */
194 :
195 : static DEFINE_MUTEX(bridge_lock);
196 : static LIST_HEAD(bridge_list);
197 :
198 : /**
199 : * drm_bridge_add - add the given bridge to the global bridge list
200 : *
201 : * @bridge: bridge control structure
202 : */
203 0 : void drm_bridge_add(struct drm_bridge *bridge)
204 : {
205 0 : mutex_init(&bridge->hpd_mutex);
206 :
207 0 : mutex_lock(&bridge_lock);
208 0 : list_add_tail(&bridge->list, &bridge_list);
209 0 : mutex_unlock(&bridge_lock);
210 0 : }
211 : EXPORT_SYMBOL(drm_bridge_add);
212 :
213 0 : static void drm_bridge_remove_void(void *bridge)
214 : {
215 0 : drm_bridge_remove(bridge);
216 0 : }
217 :
218 : /**
219 : * devm_drm_bridge_add - devm managed version of drm_bridge_add()
220 : *
221 : * @dev: device to tie the bridge lifetime to
222 : * @bridge: bridge control structure
223 : *
224 : * This is the managed version of drm_bridge_add() which automatically
225 : * calls drm_bridge_remove() when @dev is unbound.
226 : *
227 : * Return: 0 if no error or negative error code.
228 : */
229 0 : int devm_drm_bridge_add(struct device *dev, struct drm_bridge *bridge)
230 : {
231 0 : drm_bridge_add(bridge);
232 0 : return devm_add_action_or_reset(dev, drm_bridge_remove_void, bridge);
233 : }
234 : EXPORT_SYMBOL(devm_drm_bridge_add);
235 :
236 : /**
237 : * drm_bridge_remove - remove the given bridge from the global bridge list
238 : *
239 : * @bridge: bridge control structure
240 : */
241 0 : void drm_bridge_remove(struct drm_bridge *bridge)
242 : {
243 0 : mutex_lock(&bridge_lock);
244 0 : list_del_init(&bridge->list);
245 0 : mutex_unlock(&bridge_lock);
246 :
247 0 : mutex_destroy(&bridge->hpd_mutex);
248 0 : }
249 : EXPORT_SYMBOL(drm_bridge_remove);
250 :
251 : static struct drm_private_state *
252 0 : drm_bridge_atomic_duplicate_priv_state(struct drm_private_obj *obj)
253 : {
254 0 : struct drm_bridge *bridge = drm_priv_to_bridge(obj);
255 : struct drm_bridge_state *state;
256 :
257 0 : state = bridge->funcs->atomic_duplicate_state(bridge);
258 0 : return state ? &state->base : NULL;
259 : }
260 :
261 : static void
262 0 : drm_bridge_atomic_destroy_priv_state(struct drm_private_obj *obj,
263 : struct drm_private_state *s)
264 : {
265 0 : struct drm_bridge_state *state = drm_priv_to_bridge_state(s);
266 0 : struct drm_bridge *bridge = drm_priv_to_bridge(obj);
267 :
268 0 : bridge->funcs->atomic_destroy_state(bridge, state);
269 0 : }
270 :
271 : static const struct drm_private_state_funcs drm_bridge_priv_state_funcs = {
272 : .atomic_duplicate_state = drm_bridge_atomic_duplicate_priv_state,
273 : .atomic_destroy_state = drm_bridge_atomic_destroy_priv_state,
274 : };
275 :
276 : /**
277 : * drm_bridge_attach - attach the bridge to an encoder's chain
278 : *
279 : * @encoder: DRM encoder
280 : * @bridge: bridge to attach
281 : * @previous: previous bridge in the chain (optional)
282 : * @flags: DRM_BRIDGE_ATTACH_* flags
283 : *
284 : * Called by a kms driver to link the bridge to an encoder's chain. The previous
285 : * argument specifies the previous bridge in the chain. If NULL, the bridge is
286 : * linked directly at the encoder's output. Otherwise it is linked at the
287 : * previous bridge's output.
288 : *
289 : * If non-NULL the previous bridge must be already attached by a call to this
290 : * function.
291 : *
292 : * Note that bridges attached to encoders are auto-detached during encoder
293 : * cleanup in drm_encoder_cleanup(), so drm_bridge_attach() should generally
294 : * *not* be balanced with a drm_bridge_detach() in driver code.
295 : *
296 : * RETURNS:
297 : * Zero on success, error code on failure
298 : */
299 0 : int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
300 : struct drm_bridge *previous,
301 : enum drm_bridge_attach_flags flags)
302 : {
303 : int ret;
304 :
305 0 : if (!encoder || !bridge)
306 : return -EINVAL;
307 :
308 0 : if (previous && (!previous->dev || previous->encoder != encoder))
309 : return -EINVAL;
310 :
311 0 : if (bridge->dev)
312 : return -EBUSY;
313 :
314 0 : bridge->dev = encoder->dev;
315 0 : bridge->encoder = encoder;
316 :
317 0 : if (previous)
318 0 : list_add(&bridge->chain_node, &previous->chain_node);
319 : else
320 0 : list_add(&bridge->chain_node, &encoder->bridge_chain);
321 :
322 0 : if (bridge->funcs->attach) {
323 0 : ret = bridge->funcs->attach(bridge, flags);
324 0 : if (ret < 0)
325 : goto err_reset_bridge;
326 : }
327 :
328 0 : if (bridge->funcs->atomic_reset) {
329 : struct drm_bridge_state *state;
330 :
331 0 : state = bridge->funcs->atomic_reset(bridge);
332 0 : if (IS_ERR(state)) {
333 0 : ret = PTR_ERR(state);
334 : goto err_detach_bridge;
335 : }
336 :
337 0 : drm_atomic_private_obj_init(bridge->dev, &bridge->base,
338 : &state->base,
339 : &drm_bridge_priv_state_funcs);
340 : }
341 :
342 : return 0;
343 :
344 : err_detach_bridge:
345 0 : if (bridge->funcs->detach)
346 0 : bridge->funcs->detach(bridge);
347 :
348 : err_reset_bridge:
349 0 : bridge->dev = NULL;
350 0 : bridge->encoder = NULL;
351 0 : list_del(&bridge->chain_node);
352 :
353 : #ifdef CONFIG_OF
354 : DRM_ERROR("failed to attach bridge %pOF to encoder %s: %d\n",
355 : bridge->of_node, encoder->name, ret);
356 : #else
357 0 : DRM_ERROR("failed to attach bridge to encoder %s: %d\n",
358 : encoder->name, ret);
359 : #endif
360 :
361 0 : return ret;
362 : }
363 : EXPORT_SYMBOL(drm_bridge_attach);
364 :
365 0 : void drm_bridge_detach(struct drm_bridge *bridge)
366 : {
367 0 : if (WARN_ON(!bridge))
368 : return;
369 :
370 0 : if (WARN_ON(!bridge->dev))
371 : return;
372 :
373 0 : if (bridge->funcs->atomic_reset)
374 0 : drm_atomic_private_obj_fini(&bridge->base);
375 :
376 0 : if (bridge->funcs->detach)
377 0 : bridge->funcs->detach(bridge);
378 :
379 0 : list_del(&bridge->chain_node);
380 0 : bridge->dev = NULL;
381 : }
382 :
383 : /**
384 : * DOC: bridge operations
385 : *
386 : * Bridge drivers expose operations through the &drm_bridge_funcs structure.
387 : * The DRM internals (atomic and CRTC helpers) use the helpers defined in
388 : * drm_bridge.c to call bridge operations. Those operations are divided in
389 : * three big categories to support different parts of the bridge usage.
390 : *
391 : * - The encoder-related operations support control of the bridges in the
392 : * chain, and are roughly counterparts to the &drm_encoder_helper_funcs
393 : * operations. They are used by the legacy CRTC and the atomic modeset
394 : * helpers to perform mode validation, fixup and setting, and enable and
395 : * disable the bridge automatically.
396 : *
397 : * The enable and disable operations are split in
398 : * &drm_bridge_funcs.pre_enable, &drm_bridge_funcs.enable,
399 : * &drm_bridge_funcs.disable and &drm_bridge_funcs.post_disable to provide
400 : * finer-grained control.
401 : *
402 : * Bridge drivers may implement the legacy version of those operations, or
403 : * the atomic version (prefixed with atomic\_), in which case they shall also
404 : * implement the atomic state bookkeeping operations
405 : * (&drm_bridge_funcs.atomic_duplicate_state,
406 : * &drm_bridge_funcs.atomic_destroy_state and &drm_bridge_funcs.reset).
407 : * Mixing atomic and non-atomic versions of the operations is not supported.
408 : *
409 : * - The bus format negotiation operations
410 : * &drm_bridge_funcs.atomic_get_output_bus_fmts and
411 : * &drm_bridge_funcs.atomic_get_input_bus_fmts allow bridge drivers to
412 : * negotiate the formats transmitted between bridges in the chain when
413 : * multiple formats are supported. Negotiation for formats is performed
414 : * transparently for display drivers by the atomic modeset helpers. Only
415 : * atomic versions of those operations exist, bridge drivers that need to
416 : * implement them shall thus also implement the atomic version of the
417 : * encoder-related operations. This feature is not supported by the legacy
418 : * CRTC helpers.
419 : *
420 : * - The connector-related operations support implementing a &drm_connector
421 : * based on a chain of bridges. DRM bridges traditionally create a
422 : * &drm_connector for bridges meant to be used at the end of the chain. This
423 : * puts additional burden on bridge drivers, especially for bridges that may
424 : * be used in the middle of a chain or at the end of it. Furthermore, it
425 : * requires all operations of the &drm_connector to be handled by a single
426 : * bridge, which doesn't always match the hardware architecture.
427 : *
428 : * To simplify bridge drivers and make the connector implementation more
429 : * flexible, a new model allows bridges to unconditionally skip creation of
430 : * &drm_connector and instead expose &drm_bridge_funcs operations to support
431 : * an externally-implemented &drm_connector. Those operations are
432 : * &drm_bridge_funcs.detect, &drm_bridge_funcs.get_modes,
433 : * &drm_bridge_funcs.get_edid, &drm_bridge_funcs.hpd_notify,
434 : * &drm_bridge_funcs.hpd_enable and &drm_bridge_funcs.hpd_disable. When
435 : * implemented, display drivers shall create a &drm_connector instance for
436 : * each chain of bridges, and implement those connector instances based on
437 : * the bridge connector operations.
438 : *
439 : * Bridge drivers shall implement the connector-related operations for all
440 : * the features that the bridge hardware support. For instance, if a bridge
441 : * supports reading EDID, the &drm_bridge_funcs.get_edid shall be
442 : * implemented. This however doesn't mean that the DDC lines are wired to the
443 : * bridge on a particular platform, as they could also be connected to an I2C
444 : * controller of the SoC. Support for the connector-related operations on the
445 : * running platform is reported through the &drm_bridge.ops flags. Bridge
446 : * drivers shall detect which operations they can support on the platform
447 : * (usually this information is provided by ACPI or DT), and set the
448 : * &drm_bridge.ops flags for all supported operations. A flag shall only be
449 : * set if the corresponding &drm_bridge_funcs operation is implemented, but
450 : * an implemented operation doesn't necessarily imply that the corresponding
451 : * flag will be set. Display drivers shall use the &drm_bridge.ops flags to
452 : * decide which bridge to delegate a connector operation to. This mechanism
453 : * allows providing a single static const &drm_bridge_funcs instance in
454 : * bridge drivers, improving security by storing function pointers in
455 : * read-only memory.
456 : *
457 : * In order to ease transition, bridge drivers may support both the old and
458 : * new models by making connector creation optional and implementing the
459 : * connected-related bridge operations. Connector creation is then controlled
460 : * by the flags argument to the drm_bridge_attach() function. Display drivers
461 : * that support the new model and create connectors themselves shall set the
462 : * %DRM_BRIDGE_ATTACH_NO_CONNECTOR flag, and bridge drivers shall then skip
463 : * connector creation. For intermediate bridges in the chain, the flag shall
464 : * be passed to the drm_bridge_attach() call for the downstream bridge.
465 : * Bridge drivers that implement the new model only shall return an error
466 : * from their &drm_bridge_funcs.attach handler when the
467 : * %DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is not set. New display drivers
468 : * should use the new model, and convert the bridge drivers they use if
469 : * needed, in order to gradually transition to the new model.
470 : */
471 :
472 : /**
473 : * drm_bridge_chain_mode_fixup - fixup proposed mode for all bridges in the
474 : * encoder chain
475 : * @bridge: bridge control structure
476 : * @mode: desired mode to be set for the bridge
477 : * @adjusted_mode: updated mode that works for this bridge
478 : *
479 : * Calls &drm_bridge_funcs.mode_fixup for all the bridges in the
480 : * encoder chain, starting from the first bridge to the last.
481 : *
482 : * Note: the bridge passed should be the one closest to the encoder
483 : *
484 : * RETURNS:
485 : * true on success, false on failure
486 : */
487 0 : bool drm_bridge_chain_mode_fixup(struct drm_bridge *bridge,
488 : const struct drm_display_mode *mode,
489 : struct drm_display_mode *adjusted_mode)
490 : {
491 : struct drm_encoder *encoder;
492 :
493 0 : if (!bridge)
494 : return true;
495 :
496 0 : encoder = bridge->encoder;
497 0 : list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
498 0 : if (!bridge->funcs->mode_fixup)
499 0 : continue;
500 :
501 0 : if (!bridge->funcs->mode_fixup(bridge, mode, adjusted_mode))
502 : return false;
503 : }
504 :
505 : return true;
506 : }
507 : EXPORT_SYMBOL(drm_bridge_chain_mode_fixup);
508 :
509 : /**
510 : * drm_bridge_chain_mode_valid - validate the mode against all bridges in the
511 : * encoder chain.
512 : * @bridge: bridge control structure
513 : * @info: display info against which the mode shall be validated
514 : * @mode: desired mode to be validated
515 : *
516 : * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
517 : * chain, starting from the first bridge to the last. If at least one bridge
518 : * does not accept the mode the function returns the error code.
519 : *
520 : * Note: the bridge passed should be the one closest to the encoder.
521 : *
522 : * RETURNS:
523 : * MODE_OK on success, drm_mode_status Enum error code on failure
524 : */
525 : enum drm_mode_status
526 0 : drm_bridge_chain_mode_valid(struct drm_bridge *bridge,
527 : const struct drm_display_info *info,
528 : const struct drm_display_mode *mode)
529 : {
530 : struct drm_encoder *encoder;
531 :
532 0 : if (!bridge)
533 : return MODE_OK;
534 :
535 0 : encoder = bridge->encoder;
536 0 : list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
537 : enum drm_mode_status ret;
538 :
539 0 : if (!bridge->funcs->mode_valid)
540 0 : continue;
541 :
542 0 : ret = bridge->funcs->mode_valid(bridge, info, mode);
543 0 : if (ret != MODE_OK)
544 : return ret;
545 : }
546 :
547 : return MODE_OK;
548 : }
549 : EXPORT_SYMBOL(drm_bridge_chain_mode_valid);
550 :
551 : /**
552 : * drm_bridge_chain_mode_set - set proposed mode for all bridges in the
553 : * encoder chain
554 : * @bridge: bridge control structure
555 : * @mode: desired mode to be set for the encoder chain
556 : * @adjusted_mode: updated mode that works for this encoder chain
557 : *
558 : * Calls &drm_bridge_funcs.mode_set op for all the bridges in the
559 : * encoder chain, starting from the first bridge to the last.
560 : *
561 : * Note: the bridge passed should be the one closest to the encoder
562 : */
563 0 : void drm_bridge_chain_mode_set(struct drm_bridge *bridge,
564 : const struct drm_display_mode *mode,
565 : const struct drm_display_mode *adjusted_mode)
566 : {
567 : struct drm_encoder *encoder;
568 :
569 0 : if (!bridge)
570 : return;
571 :
572 0 : encoder = bridge->encoder;
573 0 : list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
574 0 : if (bridge->funcs->mode_set)
575 0 : bridge->funcs->mode_set(bridge, mode, adjusted_mode);
576 : }
577 : }
578 : EXPORT_SYMBOL(drm_bridge_chain_mode_set);
579 :
580 : /**
581 : * drm_atomic_bridge_chain_disable - disables all bridges in the encoder chain
582 : * @bridge: bridge control structure
583 : * @old_state: old atomic state
584 : *
585 : * Calls &drm_bridge_funcs.atomic_disable (falls back on
586 : * &drm_bridge_funcs.disable) op for all the bridges in the encoder chain,
587 : * starting from the last bridge to the first. These are called before calling
588 : * &drm_encoder_helper_funcs.atomic_disable
589 : *
590 : * Note: the bridge passed should be the one closest to the encoder
591 : */
592 0 : void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,
593 : struct drm_atomic_state *old_state)
594 : {
595 : struct drm_encoder *encoder;
596 : struct drm_bridge *iter;
597 :
598 0 : if (!bridge)
599 : return;
600 :
601 0 : encoder = bridge->encoder;
602 0 : list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
603 0 : if (iter->funcs->atomic_disable) {
604 : struct drm_bridge_state *old_bridge_state;
605 :
606 0 : old_bridge_state =
607 : drm_atomic_get_old_bridge_state(old_state,
608 : iter);
609 0 : if (WARN_ON(!old_bridge_state))
610 : return;
611 :
612 0 : iter->funcs->atomic_disable(iter, old_bridge_state);
613 0 : } else if (iter->funcs->disable) {
614 0 : iter->funcs->disable(iter);
615 : }
616 :
617 0 : if (iter == bridge)
618 : break;
619 : }
620 : }
621 : EXPORT_SYMBOL(drm_atomic_bridge_chain_disable);
622 :
623 0 : static void drm_atomic_bridge_call_post_disable(struct drm_bridge *bridge,
624 : struct drm_atomic_state *old_state)
625 : {
626 0 : if (old_state && bridge->funcs->atomic_post_disable) {
627 : struct drm_bridge_state *old_bridge_state;
628 :
629 0 : old_bridge_state =
630 : drm_atomic_get_old_bridge_state(old_state,
631 : bridge);
632 0 : if (WARN_ON(!old_bridge_state))
633 : return;
634 :
635 0 : bridge->funcs->atomic_post_disable(bridge,
636 : old_bridge_state);
637 0 : } else if (bridge->funcs->post_disable) {
638 0 : bridge->funcs->post_disable(bridge);
639 : }
640 : }
641 :
642 : /**
643 : * drm_atomic_bridge_chain_post_disable - cleans up after disabling all bridges
644 : * in the encoder chain
645 : * @bridge: bridge control structure
646 : * @old_state: old atomic state
647 : *
648 : * Calls &drm_bridge_funcs.atomic_post_disable (falls back on
649 : * &drm_bridge_funcs.post_disable) op for all the bridges in the encoder chain,
650 : * starting from the first bridge to the last. These are called after completing
651 : * &drm_encoder_helper_funcs.atomic_disable
652 : *
653 : * If a bridge sets @pre_enable_prev_first, then the @post_disable for that
654 : * bridge will be called before the previous one to reverse the @pre_enable
655 : * calling direction.
656 : *
657 : * Note: the bridge passed should be the one closest to the encoder
658 : */
659 0 : void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
660 : struct drm_atomic_state *old_state)
661 : {
662 : struct drm_encoder *encoder;
663 : struct drm_bridge *next, *limit;
664 :
665 0 : if (!bridge)
666 : return;
667 :
668 0 : encoder = bridge->encoder;
669 :
670 0 : list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
671 0 : limit = NULL;
672 :
673 0 : if (!list_is_last(&bridge->chain_node, &encoder->bridge_chain)) {
674 0 : next = list_next_entry(bridge, chain_node);
675 :
676 0 : if (next->pre_enable_prev_first) {
677 : /* next bridge had requested that prev
678 : * was enabled first, so disabled last
679 : */
680 : limit = next;
681 :
682 : /* Find the next bridge that has NOT requested
683 : * prev to be enabled first / disabled last
684 : */
685 0 : list_for_each_entry_from(next, &encoder->bridge_chain,
686 : chain_node) {
687 0 : if (next->pre_enable_prev_first) {
688 0 : next = list_prev_entry(next, chain_node);
689 0 : limit = next;
690 0 : break;
691 : }
692 : }
693 :
694 : /* Call these bridges in reverse order */
695 0 : list_for_each_entry_from_reverse(next, &encoder->bridge_chain,
696 : chain_node) {
697 0 : if (next == bridge)
698 : break;
699 :
700 0 : drm_atomic_bridge_call_post_disable(next,
701 : old_state);
702 : }
703 : }
704 : }
705 :
706 0 : drm_atomic_bridge_call_post_disable(bridge, old_state);
707 :
708 0 : if (limit)
709 : /* Jump all bridges that we have already post_disabled */
710 0 : bridge = limit;
711 : }
712 : }
713 : EXPORT_SYMBOL(drm_atomic_bridge_chain_post_disable);
714 :
715 0 : static void drm_atomic_bridge_call_pre_enable(struct drm_bridge *bridge,
716 : struct drm_atomic_state *old_state)
717 : {
718 0 : if (old_state && bridge->funcs->atomic_pre_enable) {
719 : struct drm_bridge_state *old_bridge_state;
720 :
721 0 : old_bridge_state =
722 : drm_atomic_get_old_bridge_state(old_state,
723 : bridge);
724 0 : if (WARN_ON(!old_bridge_state))
725 : return;
726 :
727 0 : bridge->funcs->atomic_pre_enable(bridge, old_bridge_state);
728 0 : } else if (bridge->funcs->pre_enable) {
729 0 : bridge->funcs->pre_enable(bridge);
730 : }
731 : }
732 :
733 : /**
734 : * drm_atomic_bridge_chain_pre_enable - prepares for enabling all bridges in
735 : * the encoder chain
736 : * @bridge: bridge control structure
737 : * @old_state: old atomic state
738 : *
739 : * Calls &drm_bridge_funcs.atomic_pre_enable (falls back on
740 : * &drm_bridge_funcs.pre_enable) op for all the bridges in the encoder chain,
741 : * starting from the last bridge to the first. These are called before calling
742 : * &drm_encoder_helper_funcs.atomic_enable
743 : *
744 : * If a bridge sets @pre_enable_prev_first, then the pre_enable for the
745 : * prev bridge will be called before pre_enable of this bridge.
746 : *
747 : * Note: the bridge passed should be the one closest to the encoder
748 : */
749 0 : void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
750 : struct drm_atomic_state *old_state)
751 : {
752 : struct drm_encoder *encoder;
753 : struct drm_bridge *iter, *next, *limit;
754 :
755 0 : if (!bridge)
756 : return;
757 :
758 0 : encoder = bridge->encoder;
759 :
760 0 : list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
761 0 : if (iter->pre_enable_prev_first) {
762 : next = iter;
763 : limit = bridge;
764 0 : list_for_each_entry_from_reverse(next,
765 : &encoder->bridge_chain,
766 : chain_node) {
767 0 : if (next == bridge)
768 : break;
769 :
770 0 : if (!next->pre_enable_prev_first) {
771 : /* Found first bridge that does NOT
772 : * request prev to be enabled first
773 : */
774 0 : limit = list_prev_entry(next, chain_node);
775 0 : break;
776 : }
777 : }
778 :
779 0 : list_for_each_entry_from(next, &encoder->bridge_chain, chain_node) {
780 : /* Call requested prev bridge pre_enable
781 : * in order.
782 : */
783 0 : if (next == iter)
784 : /* At the first bridge to request prev
785 : * bridges called first.
786 : */
787 : break;
788 :
789 0 : drm_atomic_bridge_call_pre_enable(next, old_state);
790 : }
791 : }
792 :
793 0 : drm_atomic_bridge_call_pre_enable(iter, old_state);
794 :
795 0 : if (iter->pre_enable_prev_first)
796 : /* Jump all bridges that we have already pre_enabled */
797 0 : iter = limit;
798 :
799 0 : if (iter == bridge)
800 : break;
801 : }
802 : }
803 : EXPORT_SYMBOL(drm_atomic_bridge_chain_pre_enable);
804 :
805 : /**
806 : * drm_atomic_bridge_chain_enable - enables all bridges in the encoder chain
807 : * @bridge: bridge control structure
808 : * @old_state: old atomic state
809 : *
810 : * Calls &drm_bridge_funcs.atomic_enable (falls back on
811 : * &drm_bridge_funcs.enable) op for all the bridges in the encoder chain,
812 : * starting from the first bridge to the last. These are called after completing
813 : * &drm_encoder_helper_funcs.atomic_enable
814 : *
815 : * Note: the bridge passed should be the one closest to the encoder
816 : */
817 0 : void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
818 : struct drm_atomic_state *old_state)
819 : {
820 : struct drm_encoder *encoder;
821 :
822 0 : if (!bridge)
823 : return;
824 :
825 0 : encoder = bridge->encoder;
826 0 : list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
827 0 : if (bridge->funcs->atomic_enable) {
828 : struct drm_bridge_state *old_bridge_state;
829 :
830 0 : old_bridge_state =
831 : drm_atomic_get_old_bridge_state(old_state,
832 : bridge);
833 0 : if (WARN_ON(!old_bridge_state))
834 : return;
835 :
836 0 : bridge->funcs->atomic_enable(bridge, old_bridge_state);
837 0 : } else if (bridge->funcs->enable) {
838 0 : bridge->funcs->enable(bridge);
839 : }
840 : }
841 : }
842 : EXPORT_SYMBOL(drm_atomic_bridge_chain_enable);
843 :
844 0 : static int drm_atomic_bridge_check(struct drm_bridge *bridge,
845 : struct drm_crtc_state *crtc_state,
846 : struct drm_connector_state *conn_state)
847 : {
848 0 : if (bridge->funcs->atomic_check) {
849 : struct drm_bridge_state *bridge_state;
850 : int ret;
851 :
852 0 : bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
853 : bridge);
854 0 : if (WARN_ON(!bridge_state))
855 : return -EINVAL;
856 :
857 0 : ret = bridge->funcs->atomic_check(bridge, bridge_state,
858 : crtc_state, conn_state);
859 0 : if (ret)
860 : return ret;
861 0 : } else if (bridge->funcs->mode_fixup) {
862 0 : if (!bridge->funcs->mode_fixup(bridge, &crtc_state->mode,
863 : &crtc_state->adjusted_mode))
864 : return -EINVAL;
865 : }
866 :
867 : return 0;
868 : }
869 :
870 0 : static int select_bus_fmt_recursive(struct drm_bridge *first_bridge,
871 : struct drm_bridge *cur_bridge,
872 : struct drm_crtc_state *crtc_state,
873 : struct drm_connector_state *conn_state,
874 : u32 out_bus_fmt)
875 : {
876 0 : unsigned int i, num_in_bus_fmts = 0;
877 : struct drm_bridge_state *cur_state;
878 : struct drm_bridge *prev_bridge;
879 : u32 *in_bus_fmts;
880 : int ret;
881 :
882 0 : prev_bridge = drm_bridge_get_prev_bridge(cur_bridge);
883 0 : cur_state = drm_atomic_get_new_bridge_state(crtc_state->state,
884 : cur_bridge);
885 :
886 : /*
887 : * If bus format negotiation is not supported by this bridge, let's
888 : * pass MEDIA_BUS_FMT_FIXED to the previous bridge in the chain and
889 : * hope that it can handle this situation gracefully (by providing
890 : * appropriate default values).
891 : */
892 0 : if (!cur_bridge->funcs->atomic_get_input_bus_fmts) {
893 0 : if (cur_bridge != first_bridge) {
894 0 : ret = select_bus_fmt_recursive(first_bridge,
895 : prev_bridge, crtc_state,
896 : conn_state,
897 : MEDIA_BUS_FMT_FIXED);
898 0 : if (ret)
899 : return ret;
900 : }
901 :
902 : /*
903 : * Driver does not implement the atomic state hooks, but that's
904 : * fine, as long as it does not access the bridge state.
905 : */
906 0 : if (cur_state) {
907 0 : cur_state->input_bus_cfg.format = MEDIA_BUS_FMT_FIXED;
908 0 : cur_state->output_bus_cfg.format = out_bus_fmt;
909 : }
910 :
911 : return 0;
912 : }
913 :
914 : /*
915 : * If the driver implements ->atomic_get_input_bus_fmts() it
916 : * should also implement the atomic state hooks.
917 : */
918 0 : if (WARN_ON(!cur_state))
919 : return -EINVAL;
920 :
921 0 : in_bus_fmts = cur_bridge->funcs->atomic_get_input_bus_fmts(cur_bridge,
922 : cur_state,
923 : crtc_state,
924 : conn_state,
925 : out_bus_fmt,
926 : &num_in_bus_fmts);
927 0 : if (!num_in_bus_fmts)
928 : return -ENOTSUPP;
929 0 : else if (!in_bus_fmts)
930 : return -ENOMEM;
931 :
932 0 : if (first_bridge == cur_bridge) {
933 0 : cur_state->input_bus_cfg.format = in_bus_fmts[0];
934 0 : cur_state->output_bus_cfg.format = out_bus_fmt;
935 0 : kfree(in_bus_fmts);
936 0 : return 0;
937 : }
938 :
939 0 : for (i = 0; i < num_in_bus_fmts; i++) {
940 0 : ret = select_bus_fmt_recursive(first_bridge, prev_bridge,
941 : crtc_state, conn_state,
942 0 : in_bus_fmts[i]);
943 0 : if (ret != -ENOTSUPP)
944 : break;
945 : }
946 :
947 0 : if (!ret) {
948 0 : cur_state->input_bus_cfg.format = in_bus_fmts[i];
949 0 : cur_state->output_bus_cfg.format = out_bus_fmt;
950 : }
951 :
952 0 : kfree(in_bus_fmts);
953 0 : return ret;
954 : }
955 :
956 : /*
957 : * This function is called by &drm_atomic_bridge_chain_check() just before
958 : * calling &drm_bridge_funcs.atomic_check() on all elements of the chain.
959 : * It performs bus format negotiation between bridge elements. The negotiation
960 : * happens in reverse order, starting from the last element in the chain up to
961 : * @bridge.
962 : *
963 : * Negotiation starts by retrieving supported output bus formats on the last
964 : * bridge element and testing them one by one. The test is recursive, meaning
965 : * that for each tested output format, the whole chain will be walked backward,
966 : * and each element will have to choose an input bus format that can be
967 : * transcoded to the requested output format. When a bridge element does not
968 : * support transcoding into a specific output format -ENOTSUPP is returned and
969 : * the next bridge element will have to try a different format. If none of the
970 : * combinations worked, -ENOTSUPP is returned and the atomic modeset will fail.
971 : *
972 : * This implementation is relying on
973 : * &drm_bridge_funcs.atomic_get_output_bus_fmts() and
974 : * &drm_bridge_funcs.atomic_get_input_bus_fmts() to gather supported
975 : * input/output formats.
976 : *
977 : * When &drm_bridge_funcs.atomic_get_output_bus_fmts() is not implemented by
978 : * the last element of the chain, &drm_atomic_bridge_chain_select_bus_fmts()
979 : * tries a single format: &drm_connector.display_info.bus_formats[0] if
980 : * available, MEDIA_BUS_FMT_FIXED otherwise.
981 : *
982 : * When &drm_bridge_funcs.atomic_get_input_bus_fmts() is not implemented,
983 : * &drm_atomic_bridge_chain_select_bus_fmts() skips the negotiation on the
984 : * bridge element that lacks this hook and asks the previous element in the
985 : * chain to try MEDIA_BUS_FMT_FIXED. It's up to bridge drivers to decide what
986 : * to do in that case (fail if they want to enforce bus format negotiation, or
987 : * provide a reasonable default if they need to support pipelines where not
988 : * all elements support bus format negotiation).
989 : */
990 : static int
991 0 : drm_atomic_bridge_chain_select_bus_fmts(struct drm_bridge *bridge,
992 : struct drm_crtc_state *crtc_state,
993 : struct drm_connector_state *conn_state)
994 : {
995 0 : struct drm_connector *conn = conn_state->connector;
996 0 : struct drm_encoder *encoder = bridge->encoder;
997 : struct drm_bridge_state *last_bridge_state;
998 0 : unsigned int i, num_out_bus_fmts = 0;
999 : struct drm_bridge *last_bridge;
1000 : u32 *out_bus_fmts;
1001 0 : int ret = 0;
1002 :
1003 0 : last_bridge = list_last_entry(&encoder->bridge_chain,
1004 : struct drm_bridge, chain_node);
1005 0 : last_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
1006 : last_bridge);
1007 :
1008 0 : if (last_bridge->funcs->atomic_get_output_bus_fmts) {
1009 0 : const struct drm_bridge_funcs *funcs = last_bridge->funcs;
1010 :
1011 : /*
1012 : * If the driver implements ->atomic_get_output_bus_fmts() it
1013 : * should also implement the atomic state hooks.
1014 : */
1015 0 : if (WARN_ON(!last_bridge_state))
1016 : return -EINVAL;
1017 :
1018 0 : out_bus_fmts = funcs->atomic_get_output_bus_fmts(last_bridge,
1019 : last_bridge_state,
1020 : crtc_state,
1021 : conn_state,
1022 : &num_out_bus_fmts);
1023 0 : if (!num_out_bus_fmts)
1024 : return -ENOTSUPP;
1025 0 : else if (!out_bus_fmts)
1026 : return -ENOMEM;
1027 : } else {
1028 0 : num_out_bus_fmts = 1;
1029 0 : out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL);
1030 0 : if (!out_bus_fmts)
1031 : return -ENOMEM;
1032 :
1033 0 : if (conn->display_info.num_bus_formats &&
1034 0 : conn->display_info.bus_formats)
1035 0 : out_bus_fmts[0] = conn->display_info.bus_formats[0];
1036 : else
1037 0 : out_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;
1038 : }
1039 :
1040 0 : for (i = 0; i < num_out_bus_fmts; i++) {
1041 0 : ret = select_bus_fmt_recursive(bridge, last_bridge, crtc_state,
1042 0 : conn_state, out_bus_fmts[i]);
1043 0 : if (ret != -ENOTSUPP)
1044 : break;
1045 : }
1046 :
1047 0 : kfree(out_bus_fmts);
1048 :
1049 0 : return ret;
1050 : }
1051 :
1052 : static void
1053 0 : drm_atomic_bridge_propagate_bus_flags(struct drm_bridge *bridge,
1054 : struct drm_connector *conn,
1055 : struct drm_atomic_state *state)
1056 : {
1057 : struct drm_bridge_state *bridge_state, *next_bridge_state;
1058 : struct drm_bridge *next_bridge;
1059 0 : u32 output_flags = 0;
1060 :
1061 0 : bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
1062 :
1063 : /* No bridge state attached to this bridge => nothing to propagate. */
1064 0 : if (!bridge_state)
1065 : return;
1066 :
1067 0 : next_bridge = drm_bridge_get_next_bridge(bridge);
1068 :
1069 : /*
1070 : * Let's try to apply the most common case here, that is, propagate
1071 : * display_info flags for the last bridge, and propagate the input
1072 : * flags of the next bridge element to the output end of the current
1073 : * bridge when the bridge is not the last one.
1074 : * There are exceptions to this rule, like when signal inversion is
1075 : * happening at the board level, but that's something drivers can deal
1076 : * with from their &drm_bridge_funcs.atomic_check() implementation by
1077 : * simply overriding the flags value we've set here.
1078 : */
1079 0 : if (!next_bridge) {
1080 0 : output_flags = conn->display_info.bus_flags;
1081 : } else {
1082 0 : next_bridge_state = drm_atomic_get_new_bridge_state(state,
1083 : next_bridge);
1084 : /*
1085 : * No bridge state attached to the next bridge, just leave the
1086 : * flags to 0.
1087 : */
1088 0 : if (next_bridge_state)
1089 0 : output_flags = next_bridge_state->input_bus_cfg.flags;
1090 : }
1091 :
1092 0 : bridge_state->output_bus_cfg.flags = output_flags;
1093 :
1094 : /*
1095 : * Propagate the output flags to the input end of the bridge. Again, it's
1096 : * not necessarily what all bridges want, but that's what most of them
1097 : * do, and by doing that by default we avoid forcing drivers to
1098 : * duplicate the "dummy propagation" logic.
1099 : */
1100 0 : bridge_state->input_bus_cfg.flags = output_flags;
1101 : }
1102 :
1103 : /**
1104 : * drm_atomic_bridge_chain_check() - Do an atomic check on the bridge chain
1105 : * @bridge: bridge control structure
1106 : * @crtc_state: new CRTC state
1107 : * @conn_state: new connector state
1108 : *
1109 : * First trigger a bus format negotiation before calling
1110 : * &drm_bridge_funcs.atomic_check() (falls back on
1111 : * &drm_bridge_funcs.mode_fixup()) op for all the bridges in the encoder chain,
1112 : * starting from the last bridge to the first. These are called before calling
1113 : * &drm_encoder_helper_funcs.atomic_check()
1114 : *
1115 : * RETURNS:
1116 : * 0 on success, a negative error code on failure
1117 : */
1118 0 : int drm_atomic_bridge_chain_check(struct drm_bridge *bridge,
1119 : struct drm_crtc_state *crtc_state,
1120 : struct drm_connector_state *conn_state)
1121 : {
1122 0 : struct drm_connector *conn = conn_state->connector;
1123 : struct drm_encoder *encoder;
1124 : struct drm_bridge *iter;
1125 : int ret;
1126 :
1127 0 : if (!bridge)
1128 : return 0;
1129 :
1130 0 : ret = drm_atomic_bridge_chain_select_bus_fmts(bridge, crtc_state,
1131 : conn_state);
1132 0 : if (ret)
1133 : return ret;
1134 :
1135 0 : encoder = bridge->encoder;
1136 0 : list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
1137 : int ret;
1138 :
1139 : /*
1140 : * Bus flags are propagated by default. If a bridge needs to
1141 : * tweak the input bus flags for any reason, it should happen
1142 : * in its &drm_bridge_funcs.atomic_check() implementation such
1143 : * that preceding bridges in the chain can propagate the new
1144 : * bus flags.
1145 : */
1146 0 : drm_atomic_bridge_propagate_bus_flags(iter, conn,
1147 : crtc_state->state);
1148 :
1149 0 : ret = drm_atomic_bridge_check(iter, crtc_state, conn_state);
1150 0 : if (ret)
1151 : return ret;
1152 :
1153 0 : if (iter == bridge)
1154 : break;
1155 : }
1156 :
1157 : return 0;
1158 : }
1159 : EXPORT_SYMBOL(drm_atomic_bridge_chain_check);
1160 :
1161 : /**
1162 : * drm_bridge_detect - check if anything is attached to the bridge output
1163 : * @bridge: bridge control structure
1164 : *
1165 : * If the bridge supports output detection, as reported by the
1166 : * DRM_BRIDGE_OP_DETECT bridge ops flag, call &drm_bridge_funcs.detect for the
1167 : * bridge and return the connection status. Otherwise return
1168 : * connector_status_unknown.
1169 : *
1170 : * RETURNS:
1171 : * The detection status on success, or connector_status_unknown if the bridge
1172 : * doesn't support output detection.
1173 : */
1174 0 : enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge)
1175 : {
1176 0 : if (!(bridge->ops & DRM_BRIDGE_OP_DETECT))
1177 : return connector_status_unknown;
1178 :
1179 0 : return bridge->funcs->detect(bridge);
1180 : }
1181 : EXPORT_SYMBOL_GPL(drm_bridge_detect);
1182 :
1183 : /**
1184 : * drm_bridge_get_modes - fill all modes currently valid for the sink into the
1185 : * @connector
1186 : * @bridge: bridge control structure
1187 : * @connector: the connector to fill with modes
1188 : *
1189 : * If the bridge supports output modes retrieval, as reported by the
1190 : * DRM_BRIDGE_OP_MODES bridge ops flag, call &drm_bridge_funcs.get_modes to
1191 : * fill the connector with all valid modes and return the number of modes
1192 : * added. Otherwise return 0.
1193 : *
1194 : * RETURNS:
1195 : * The number of modes added to the connector.
1196 : */
1197 0 : int drm_bridge_get_modes(struct drm_bridge *bridge,
1198 : struct drm_connector *connector)
1199 : {
1200 0 : if (!(bridge->ops & DRM_BRIDGE_OP_MODES))
1201 : return 0;
1202 :
1203 0 : return bridge->funcs->get_modes(bridge, connector);
1204 : }
1205 : EXPORT_SYMBOL_GPL(drm_bridge_get_modes);
1206 :
1207 : /**
1208 : * drm_bridge_get_edid - get the EDID data of the connected display
1209 : * @bridge: bridge control structure
1210 : * @connector: the connector to read EDID for
1211 : *
1212 : * If the bridge supports output EDID retrieval, as reported by the
1213 : * DRM_BRIDGE_OP_EDID bridge ops flag, call &drm_bridge_funcs.get_edid to
1214 : * get the EDID and return it. Otherwise return NULL.
1215 : *
1216 : * RETURNS:
1217 : * The retrieved EDID on success, or NULL otherwise.
1218 : */
1219 0 : struct edid *drm_bridge_get_edid(struct drm_bridge *bridge,
1220 : struct drm_connector *connector)
1221 : {
1222 0 : if (!(bridge->ops & DRM_BRIDGE_OP_EDID))
1223 : return NULL;
1224 :
1225 0 : return bridge->funcs->get_edid(bridge, connector);
1226 : }
1227 : EXPORT_SYMBOL_GPL(drm_bridge_get_edid);
1228 :
1229 : /**
1230 : * drm_bridge_hpd_enable - enable hot plug detection for the bridge
1231 : * @bridge: bridge control structure
1232 : * @cb: hot-plug detection callback
1233 : * @data: data to be passed to the hot-plug detection callback
1234 : *
1235 : * Call &drm_bridge_funcs.hpd_enable if implemented and register the given @cb
1236 : * and @data as hot plug notification callback. From now on the @cb will be
1237 : * called with @data when an output status change is detected by the bridge,
1238 : * until hot plug notification gets disabled with drm_bridge_hpd_disable().
1239 : *
1240 : * Hot plug detection is supported only if the DRM_BRIDGE_OP_HPD flag is set in
1241 : * bridge->ops. This function shall not be called when the flag is not set.
1242 : *
1243 : * Only one hot plug detection callback can be registered at a time, it is an
1244 : * error to call this function when hot plug detection is already enabled for
1245 : * the bridge.
1246 : */
1247 0 : void drm_bridge_hpd_enable(struct drm_bridge *bridge,
1248 : void (*cb)(void *data,
1249 : enum drm_connector_status status),
1250 : void *data)
1251 : {
1252 0 : if (!(bridge->ops & DRM_BRIDGE_OP_HPD))
1253 : return;
1254 :
1255 0 : mutex_lock(&bridge->hpd_mutex);
1256 :
1257 0 : if (WARN(bridge->hpd_cb, "Hot plug detection already enabled\n"))
1258 : goto unlock;
1259 :
1260 0 : bridge->hpd_cb = cb;
1261 0 : bridge->hpd_data = data;
1262 :
1263 0 : if (bridge->funcs->hpd_enable)
1264 0 : bridge->funcs->hpd_enable(bridge);
1265 :
1266 : unlock:
1267 0 : mutex_unlock(&bridge->hpd_mutex);
1268 : }
1269 : EXPORT_SYMBOL_GPL(drm_bridge_hpd_enable);
1270 :
1271 : /**
1272 : * drm_bridge_hpd_disable - disable hot plug detection for the bridge
1273 : * @bridge: bridge control structure
1274 : *
1275 : * Call &drm_bridge_funcs.hpd_disable if implemented and unregister the hot
1276 : * plug detection callback previously registered with drm_bridge_hpd_enable().
1277 : * Once this function returns the callback will not be called by the bridge
1278 : * when an output status change occurs.
1279 : *
1280 : * Hot plug detection is supported only if the DRM_BRIDGE_OP_HPD flag is set in
1281 : * bridge->ops. This function shall not be called when the flag is not set.
1282 : */
1283 0 : void drm_bridge_hpd_disable(struct drm_bridge *bridge)
1284 : {
1285 0 : if (!(bridge->ops & DRM_BRIDGE_OP_HPD))
1286 : return;
1287 :
1288 0 : mutex_lock(&bridge->hpd_mutex);
1289 0 : if (bridge->funcs->hpd_disable)
1290 0 : bridge->funcs->hpd_disable(bridge);
1291 :
1292 0 : bridge->hpd_cb = NULL;
1293 0 : bridge->hpd_data = NULL;
1294 0 : mutex_unlock(&bridge->hpd_mutex);
1295 : }
1296 : EXPORT_SYMBOL_GPL(drm_bridge_hpd_disable);
1297 :
1298 : /**
1299 : * drm_bridge_hpd_notify - notify hot plug detection events
1300 : * @bridge: bridge control structure
1301 : * @status: output connection status
1302 : *
1303 : * Bridge drivers shall call this function to report hot plug events when they
1304 : * detect a change in the output status, when hot plug detection has been
1305 : * enabled by drm_bridge_hpd_enable().
1306 : *
1307 : * This function shall be called in a context that can sleep.
1308 : */
1309 0 : void drm_bridge_hpd_notify(struct drm_bridge *bridge,
1310 : enum drm_connector_status status)
1311 : {
1312 0 : mutex_lock(&bridge->hpd_mutex);
1313 0 : if (bridge->hpd_cb)
1314 0 : bridge->hpd_cb(bridge->hpd_data, status);
1315 0 : mutex_unlock(&bridge->hpd_mutex);
1316 0 : }
1317 : EXPORT_SYMBOL_GPL(drm_bridge_hpd_notify);
1318 :
1319 : #ifdef CONFIG_OF
1320 : /**
1321 : * of_drm_find_bridge - find the bridge corresponding to the device node in
1322 : * the global bridge list
1323 : *
1324 : * @np: device node
1325 : *
1326 : * RETURNS:
1327 : * drm_bridge control struct on success, NULL on failure
1328 : */
1329 : struct drm_bridge *of_drm_find_bridge(struct device_node *np)
1330 : {
1331 : struct drm_bridge *bridge;
1332 :
1333 : mutex_lock(&bridge_lock);
1334 :
1335 : list_for_each_entry(bridge, &bridge_list, list) {
1336 : if (bridge->of_node == np) {
1337 : mutex_unlock(&bridge_lock);
1338 : return bridge;
1339 : }
1340 : }
1341 :
1342 : mutex_unlock(&bridge_lock);
1343 : return NULL;
1344 : }
1345 : EXPORT_SYMBOL(of_drm_find_bridge);
1346 : #endif
1347 :
1348 : MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
1349 : MODULE_DESCRIPTION("DRM bridge infrastructure");
1350 : MODULE_LICENSE("GPL and additional rights");
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