cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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drm_atomic_state_helper.c (21694B)


      1/*
      2 * Copyright (C) 2018 Intel Corp.
      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, sublicense,
      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 shall be included in
     12 * all copies or substantial portions of the Software.
     13 *
     14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
     18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     20 * OTHER DEALINGS IN THE SOFTWARE.
     21 *
     22 * Authors:
     23 * Rob Clark <robdclark@gmail.com>
     24 * Daniel Vetter <daniel.vetter@ffwll.ch>
     25 */
     26
     27#include <drm/drm_atomic.h>
     28#include <drm/drm_atomic_state_helper.h>
     29#include <drm/drm_bridge.h>
     30#include <drm/drm_connector.h>
     31#include <drm/drm_crtc.h>
     32#include <drm/drm_device.h>
     33#include <drm/drm_plane.h>
     34#include <drm/drm_print.h>
     35#include <drm/drm_vblank.h>
     36#include <drm/drm_writeback.h>
     37
     38#include <linux/slab.h>
     39#include <linux/dma-fence.h>
     40
     41/**
     42 * DOC: atomic state reset and initialization
     43 *
     44 * Both the drm core and the atomic helpers assume that there is always the full
     45 * and correct atomic software state for all connectors, CRTCs and planes
     46 * available. Which is a bit a problem on driver load and also after system
     47 * suspend. One way to solve this is to have a hardware state read-out
     48 * infrastructure which reconstructs the full software state (e.g. the i915
     49 * driver).
     50 *
     51 * The simpler solution is to just reset the software state to everything off,
     52 * which is easiest to do by calling drm_mode_config_reset(). To facilitate this
     53 * the atomic helpers provide default reset implementations for all hooks.
     54 *
     55 * On the upside the precise state tracking of atomic simplifies system suspend
     56 * and resume a lot. For drivers using drm_mode_config_reset() a complete recipe
     57 * is implemented in drm_atomic_helper_suspend() and drm_atomic_helper_resume().
     58 * For other drivers the building blocks are split out, see the documentation
     59 * for these functions.
     60 */
     61
     62/**
     63 * __drm_atomic_helper_crtc_state_reset - reset the CRTC state
     64 * @crtc_state: atomic CRTC state, must not be NULL
     65 * @crtc: CRTC object, must not be NULL
     66 *
     67 * Initializes the newly allocated @crtc_state with default
     68 * values. This is useful for drivers that subclass the CRTC state.
     69 */
     70void
     71__drm_atomic_helper_crtc_state_reset(struct drm_crtc_state *crtc_state,
     72				     struct drm_crtc *crtc)
     73{
     74	crtc_state->crtc = crtc;
     75}
     76EXPORT_SYMBOL(__drm_atomic_helper_crtc_state_reset);
     77
     78/**
     79 * __drm_atomic_helper_crtc_reset - reset state on CRTC
     80 * @crtc: drm CRTC
     81 * @crtc_state: CRTC state to assign
     82 *
     83 * Initializes the newly allocated @crtc_state and assigns it to
     84 * the &drm_crtc->state pointer of @crtc, usually required when
     85 * initializing the drivers or when called from the &drm_crtc_funcs.reset
     86 * hook.
     87 *
     88 * This is useful for drivers that subclass the CRTC state.
     89 */
     90void
     91__drm_atomic_helper_crtc_reset(struct drm_crtc *crtc,
     92			       struct drm_crtc_state *crtc_state)
     93{
     94	if (crtc_state)
     95		__drm_atomic_helper_crtc_state_reset(crtc_state, crtc);
     96
     97	if (drm_dev_has_vblank(crtc->dev))
     98		drm_crtc_vblank_reset(crtc);
     99
    100	crtc->state = crtc_state;
    101}
    102EXPORT_SYMBOL(__drm_atomic_helper_crtc_reset);
    103
    104/**
    105 * drm_atomic_helper_crtc_reset - default &drm_crtc_funcs.reset hook for CRTCs
    106 * @crtc: drm CRTC
    107 *
    108 * Resets the atomic state for @crtc by freeing the state pointer (which might
    109 * be NULL, e.g. at driver load time) and allocating a new empty state object.
    110 */
    111void drm_atomic_helper_crtc_reset(struct drm_crtc *crtc)
    112{
    113	struct drm_crtc_state *crtc_state =
    114		kzalloc(sizeof(*crtc->state), GFP_KERNEL);
    115
    116	if (crtc->state)
    117		crtc->funcs->atomic_destroy_state(crtc, crtc->state);
    118
    119	__drm_atomic_helper_crtc_reset(crtc, crtc_state);
    120}
    121EXPORT_SYMBOL(drm_atomic_helper_crtc_reset);
    122
    123/**
    124 * __drm_atomic_helper_crtc_duplicate_state - copy atomic CRTC state
    125 * @crtc: CRTC object
    126 * @state: atomic CRTC state
    127 *
    128 * Copies atomic state from a CRTC's current state and resets inferred values.
    129 * This is useful for drivers that subclass the CRTC state.
    130 */
    131void __drm_atomic_helper_crtc_duplicate_state(struct drm_crtc *crtc,
    132					      struct drm_crtc_state *state)
    133{
    134	memcpy(state, crtc->state, sizeof(*state));
    135
    136	if (state->mode_blob)
    137		drm_property_blob_get(state->mode_blob);
    138	if (state->degamma_lut)
    139		drm_property_blob_get(state->degamma_lut);
    140	if (state->ctm)
    141		drm_property_blob_get(state->ctm);
    142	if (state->gamma_lut)
    143		drm_property_blob_get(state->gamma_lut);
    144	state->mode_changed = false;
    145	state->active_changed = false;
    146	state->planes_changed = false;
    147	state->connectors_changed = false;
    148	state->color_mgmt_changed = false;
    149	state->zpos_changed = false;
    150	state->commit = NULL;
    151	state->event = NULL;
    152	state->async_flip = false;
    153
    154	/* Self refresh should be canceled when a new update is available */
    155	state->active = drm_atomic_crtc_effectively_active(state);
    156	state->self_refresh_active = false;
    157}
    158EXPORT_SYMBOL(__drm_atomic_helper_crtc_duplicate_state);
    159
    160/**
    161 * drm_atomic_helper_crtc_duplicate_state - default state duplicate hook
    162 * @crtc: drm CRTC
    163 *
    164 * Default CRTC state duplicate hook for drivers which don't have their own
    165 * subclassed CRTC state structure.
    166 */
    167struct drm_crtc_state *
    168drm_atomic_helper_crtc_duplicate_state(struct drm_crtc *crtc)
    169{
    170	struct drm_crtc_state *state;
    171
    172	if (WARN_ON(!crtc->state))
    173		return NULL;
    174
    175	state = kmalloc(sizeof(*state), GFP_KERNEL);
    176	if (state)
    177		__drm_atomic_helper_crtc_duplicate_state(crtc, state);
    178
    179	return state;
    180}
    181EXPORT_SYMBOL(drm_atomic_helper_crtc_duplicate_state);
    182
    183/**
    184 * __drm_atomic_helper_crtc_destroy_state - release CRTC state
    185 * @state: CRTC state object to release
    186 *
    187 * Releases all resources stored in the CRTC state without actually freeing
    188 * the memory of the CRTC state. This is useful for drivers that subclass the
    189 * CRTC state.
    190 */
    191void __drm_atomic_helper_crtc_destroy_state(struct drm_crtc_state *state)
    192{
    193	if (state->commit) {
    194		/*
    195		 * In the event that a non-blocking commit returns
    196		 * -ERESTARTSYS before the commit_tail work is queued, we will
    197		 * have an extra reference to the commit object. Release it, if
    198		 * the event has not been consumed by the worker.
    199		 *
    200		 * state->event may be freed, so we can't directly look at
    201		 * state->event->base.completion.
    202		 */
    203		if (state->event && state->commit->abort_completion)
    204			drm_crtc_commit_put(state->commit);
    205
    206		kfree(state->commit->event);
    207		state->commit->event = NULL;
    208
    209		drm_crtc_commit_put(state->commit);
    210	}
    211
    212	drm_property_blob_put(state->mode_blob);
    213	drm_property_blob_put(state->degamma_lut);
    214	drm_property_blob_put(state->ctm);
    215	drm_property_blob_put(state->gamma_lut);
    216}
    217EXPORT_SYMBOL(__drm_atomic_helper_crtc_destroy_state);
    218
    219/**
    220 * drm_atomic_helper_crtc_destroy_state - default state destroy hook
    221 * @crtc: drm CRTC
    222 * @state: CRTC state object to release
    223 *
    224 * Default CRTC state destroy hook for drivers which don't have their own
    225 * subclassed CRTC state structure.
    226 */
    227void drm_atomic_helper_crtc_destroy_state(struct drm_crtc *crtc,
    228					  struct drm_crtc_state *state)
    229{
    230	__drm_atomic_helper_crtc_destroy_state(state);
    231	kfree(state);
    232}
    233EXPORT_SYMBOL(drm_atomic_helper_crtc_destroy_state);
    234
    235/**
    236 * __drm_atomic_helper_plane_state_reset - resets plane state to default values
    237 * @plane_state: atomic plane state, must not be NULL
    238 * @plane: plane object, must not be NULL
    239 *
    240 * Initializes the newly allocated @plane_state with default
    241 * values. This is useful for drivers that subclass the CRTC state.
    242 */
    243void __drm_atomic_helper_plane_state_reset(struct drm_plane_state *plane_state,
    244					   struct drm_plane *plane)
    245{
    246	u64 val;
    247
    248	plane_state->plane = plane;
    249	plane_state->rotation = DRM_MODE_ROTATE_0;
    250
    251	plane_state->alpha = DRM_BLEND_ALPHA_OPAQUE;
    252	plane_state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI;
    253
    254	if (plane->color_encoding_property) {
    255		if (!drm_object_property_get_default_value(&plane->base,
    256							   plane->color_encoding_property,
    257							   &val))
    258			plane_state->color_encoding = val;
    259	}
    260
    261	if (plane->color_range_property) {
    262		if (!drm_object_property_get_default_value(&plane->base,
    263							   plane->color_range_property,
    264							   &val))
    265			plane_state->color_range = val;
    266	}
    267
    268	if (plane->zpos_property) {
    269		if (!drm_object_property_get_default_value(&plane->base,
    270							   plane->zpos_property,
    271							   &val)) {
    272			plane_state->zpos = val;
    273			plane_state->normalized_zpos = val;
    274		}
    275	}
    276}
    277EXPORT_SYMBOL(__drm_atomic_helper_plane_state_reset);
    278
    279/**
    280 * __drm_atomic_helper_plane_reset - reset state on plane
    281 * @plane: drm plane
    282 * @plane_state: plane state to assign
    283 *
    284 * Initializes the newly allocated @plane_state and assigns it to
    285 * the &drm_crtc->state pointer of @plane, usually required when
    286 * initializing the drivers or when called from the &drm_plane_funcs.reset
    287 * hook.
    288 *
    289 * This is useful for drivers that subclass the plane state.
    290 */
    291void __drm_atomic_helper_plane_reset(struct drm_plane *plane,
    292				     struct drm_plane_state *plane_state)
    293{
    294	if (plane_state)
    295		__drm_atomic_helper_plane_state_reset(plane_state, plane);
    296
    297	plane->state = plane_state;
    298}
    299EXPORT_SYMBOL(__drm_atomic_helper_plane_reset);
    300
    301/**
    302 * drm_atomic_helper_plane_reset - default &drm_plane_funcs.reset hook for planes
    303 * @plane: drm plane
    304 *
    305 * Resets the atomic state for @plane by freeing the state pointer (which might
    306 * be NULL, e.g. at driver load time) and allocating a new empty state object.
    307 */
    308void drm_atomic_helper_plane_reset(struct drm_plane *plane)
    309{
    310	if (plane->state)
    311		__drm_atomic_helper_plane_destroy_state(plane->state);
    312
    313	kfree(plane->state);
    314	plane->state = kzalloc(sizeof(*plane->state), GFP_KERNEL);
    315	if (plane->state)
    316		__drm_atomic_helper_plane_reset(plane, plane->state);
    317}
    318EXPORT_SYMBOL(drm_atomic_helper_plane_reset);
    319
    320/**
    321 * __drm_atomic_helper_plane_duplicate_state - copy atomic plane state
    322 * @plane: plane object
    323 * @state: atomic plane state
    324 *
    325 * Copies atomic state from a plane's current state. This is useful for
    326 * drivers that subclass the plane state.
    327 */
    328void __drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane,
    329					       struct drm_plane_state *state)
    330{
    331	memcpy(state, plane->state, sizeof(*state));
    332
    333	if (state->fb)
    334		drm_framebuffer_get(state->fb);
    335
    336	state->fence = NULL;
    337	state->commit = NULL;
    338	state->fb_damage_clips = NULL;
    339}
    340EXPORT_SYMBOL(__drm_atomic_helper_plane_duplicate_state);
    341
    342/**
    343 * drm_atomic_helper_plane_duplicate_state - default state duplicate hook
    344 * @plane: drm plane
    345 *
    346 * Default plane state duplicate hook for drivers which don't have their own
    347 * subclassed plane state structure.
    348 */
    349struct drm_plane_state *
    350drm_atomic_helper_plane_duplicate_state(struct drm_plane *plane)
    351{
    352	struct drm_plane_state *state;
    353
    354	if (WARN_ON(!plane->state))
    355		return NULL;
    356
    357	state = kmalloc(sizeof(*state), GFP_KERNEL);
    358	if (state)
    359		__drm_atomic_helper_plane_duplicate_state(plane, state);
    360
    361	return state;
    362}
    363EXPORT_SYMBOL(drm_atomic_helper_plane_duplicate_state);
    364
    365/**
    366 * __drm_atomic_helper_plane_destroy_state - release plane state
    367 * @state: plane state object to release
    368 *
    369 * Releases all resources stored in the plane state without actually freeing
    370 * the memory of the plane state. This is useful for drivers that subclass the
    371 * plane state.
    372 */
    373void __drm_atomic_helper_plane_destroy_state(struct drm_plane_state *state)
    374{
    375	if (state->fb)
    376		drm_framebuffer_put(state->fb);
    377
    378	if (state->fence)
    379		dma_fence_put(state->fence);
    380
    381	if (state->commit)
    382		drm_crtc_commit_put(state->commit);
    383
    384	drm_property_blob_put(state->fb_damage_clips);
    385}
    386EXPORT_SYMBOL(__drm_atomic_helper_plane_destroy_state);
    387
    388/**
    389 * drm_atomic_helper_plane_destroy_state - default state destroy hook
    390 * @plane: drm plane
    391 * @state: plane state object to release
    392 *
    393 * Default plane state destroy hook for drivers which don't have their own
    394 * subclassed plane state structure.
    395 */
    396void drm_atomic_helper_plane_destroy_state(struct drm_plane *plane,
    397					   struct drm_plane_state *state)
    398{
    399	__drm_atomic_helper_plane_destroy_state(state);
    400	kfree(state);
    401}
    402EXPORT_SYMBOL(drm_atomic_helper_plane_destroy_state);
    403
    404/**
    405 * __drm_atomic_helper_connector_state_reset - reset the connector state
    406 * @conn_state: atomic connector state, must not be NULL
    407 * @connector: connectotr object, must not be NULL
    408 *
    409 * Initializes the newly allocated @conn_state with default
    410 * values. This is useful for drivers that subclass the connector state.
    411 */
    412void
    413__drm_atomic_helper_connector_state_reset(struct drm_connector_state *conn_state,
    414					  struct drm_connector *connector)
    415{
    416	conn_state->connector = connector;
    417}
    418EXPORT_SYMBOL(__drm_atomic_helper_connector_state_reset);
    419
    420/**
    421 * __drm_atomic_helper_connector_reset - reset state on connector
    422 * @connector: drm connector
    423 * @conn_state: connector state to assign
    424 *
    425 * Initializes the newly allocated @conn_state and assigns it to
    426 * the &drm_connector->state pointer of @connector, usually required when
    427 * initializing the drivers or when called from the &drm_connector_funcs.reset
    428 * hook.
    429 *
    430 * This is useful for drivers that subclass the connector state.
    431 */
    432void
    433__drm_atomic_helper_connector_reset(struct drm_connector *connector,
    434				    struct drm_connector_state *conn_state)
    435{
    436	if (conn_state)
    437		__drm_atomic_helper_connector_state_reset(conn_state, connector);
    438
    439	connector->state = conn_state;
    440}
    441EXPORT_SYMBOL(__drm_atomic_helper_connector_reset);
    442
    443/**
    444 * drm_atomic_helper_connector_reset - default &drm_connector_funcs.reset hook for connectors
    445 * @connector: drm connector
    446 *
    447 * Resets the atomic state for @connector by freeing the state pointer (which
    448 * might be NULL, e.g. at driver load time) and allocating a new empty state
    449 * object.
    450 */
    451void drm_atomic_helper_connector_reset(struct drm_connector *connector)
    452{
    453	struct drm_connector_state *conn_state =
    454		kzalloc(sizeof(*conn_state), GFP_KERNEL);
    455
    456	if (connector->state)
    457		__drm_atomic_helper_connector_destroy_state(connector->state);
    458
    459	kfree(connector->state);
    460	__drm_atomic_helper_connector_reset(connector, conn_state);
    461}
    462EXPORT_SYMBOL(drm_atomic_helper_connector_reset);
    463
    464/**
    465 * drm_atomic_helper_connector_tv_reset - Resets TV connector properties
    466 * @connector: DRM connector
    467 *
    468 * Resets the TV-related properties attached to a connector.
    469 */
    470void drm_atomic_helper_connector_tv_reset(struct drm_connector *connector)
    471{
    472	struct drm_cmdline_mode *cmdline = &connector->cmdline_mode;
    473	struct drm_connector_state *state = connector->state;
    474
    475	state->tv.margins.left = cmdline->tv_margins.left;
    476	state->tv.margins.right = cmdline->tv_margins.right;
    477	state->tv.margins.top = cmdline->tv_margins.top;
    478	state->tv.margins.bottom = cmdline->tv_margins.bottom;
    479}
    480EXPORT_SYMBOL(drm_atomic_helper_connector_tv_reset);
    481
    482/**
    483 * __drm_atomic_helper_connector_duplicate_state - copy atomic connector state
    484 * @connector: connector object
    485 * @state: atomic connector state
    486 *
    487 * Copies atomic state from a connector's current state. This is useful for
    488 * drivers that subclass the connector state.
    489 */
    490void
    491__drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector,
    492					    struct drm_connector_state *state)
    493{
    494	memcpy(state, connector->state, sizeof(*state));
    495	if (state->crtc)
    496		drm_connector_get(connector);
    497	state->commit = NULL;
    498
    499	if (state->hdr_output_metadata)
    500		drm_property_blob_get(state->hdr_output_metadata);
    501
    502	/* Don't copy over a writeback job, they are used only once */
    503	state->writeback_job = NULL;
    504}
    505EXPORT_SYMBOL(__drm_atomic_helper_connector_duplicate_state);
    506
    507/**
    508 * drm_atomic_helper_connector_duplicate_state - default state duplicate hook
    509 * @connector: drm connector
    510 *
    511 * Default connector state duplicate hook for drivers which don't have their own
    512 * subclassed connector state structure.
    513 */
    514struct drm_connector_state *
    515drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector)
    516{
    517	struct drm_connector_state *state;
    518
    519	if (WARN_ON(!connector->state))
    520		return NULL;
    521
    522	state = kmalloc(sizeof(*state), GFP_KERNEL);
    523	if (state)
    524		__drm_atomic_helper_connector_duplicate_state(connector, state);
    525
    526	return state;
    527}
    528EXPORT_SYMBOL(drm_atomic_helper_connector_duplicate_state);
    529
    530/**
    531 * __drm_atomic_helper_connector_destroy_state - release connector state
    532 * @state: connector state object to release
    533 *
    534 * Releases all resources stored in the connector state without actually
    535 * freeing the memory of the connector state. This is useful for drivers that
    536 * subclass the connector state.
    537 */
    538void
    539__drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state)
    540{
    541	if (state->crtc)
    542		drm_connector_put(state->connector);
    543
    544	if (state->commit)
    545		drm_crtc_commit_put(state->commit);
    546
    547	if (state->writeback_job)
    548		drm_writeback_cleanup_job(state->writeback_job);
    549
    550	drm_property_blob_put(state->hdr_output_metadata);
    551}
    552EXPORT_SYMBOL(__drm_atomic_helper_connector_destroy_state);
    553
    554/**
    555 * drm_atomic_helper_connector_destroy_state - default state destroy hook
    556 * @connector: drm connector
    557 * @state: connector state object to release
    558 *
    559 * Default connector state destroy hook for drivers which don't have their own
    560 * subclassed connector state structure.
    561 */
    562void drm_atomic_helper_connector_destroy_state(struct drm_connector *connector,
    563					  struct drm_connector_state *state)
    564{
    565	__drm_atomic_helper_connector_destroy_state(state);
    566	kfree(state);
    567}
    568EXPORT_SYMBOL(drm_atomic_helper_connector_destroy_state);
    569
    570/**
    571 * __drm_atomic_helper_private_obj_duplicate_state - copy atomic private state
    572 * @obj: CRTC object
    573 * @state: new private object state
    574 *
    575 * Copies atomic state from a private objects's current state and resets inferred values.
    576 * This is useful for drivers that subclass the private state.
    577 */
    578void __drm_atomic_helper_private_obj_duplicate_state(struct drm_private_obj *obj,
    579						     struct drm_private_state *state)
    580{
    581	memcpy(state, obj->state, sizeof(*state));
    582}
    583EXPORT_SYMBOL(__drm_atomic_helper_private_obj_duplicate_state);
    584
    585/**
    586 * __drm_atomic_helper_bridge_duplicate_state() - Copy atomic bridge state
    587 * @bridge: bridge object
    588 * @state: atomic bridge state
    589 *
    590 * Copies atomic state from a bridge's current state and resets inferred values.
    591 * This is useful for drivers that subclass the bridge state.
    592 */
    593void __drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge,
    594						struct drm_bridge_state *state)
    595{
    596	__drm_atomic_helper_private_obj_duplicate_state(&bridge->base,
    597							&state->base);
    598	state->bridge = bridge;
    599}
    600EXPORT_SYMBOL(__drm_atomic_helper_bridge_duplicate_state);
    601
    602/**
    603 * drm_atomic_helper_bridge_duplicate_state() - Duplicate a bridge state object
    604 * @bridge: bridge object
    605 *
    606 * Allocates a new bridge state and initializes it with the current bridge
    607 * state values. This helper is meant to be used as a bridge
    608 * &drm_bridge_funcs.atomic_duplicate_state hook for bridges that don't
    609 * subclass the bridge state.
    610 */
    611struct drm_bridge_state *
    612drm_atomic_helper_bridge_duplicate_state(struct drm_bridge *bridge)
    613{
    614	struct drm_bridge_state *new;
    615
    616	if (WARN_ON(!bridge->base.state))
    617		return NULL;
    618
    619	new = kzalloc(sizeof(*new), GFP_KERNEL);
    620	if (new)
    621		__drm_atomic_helper_bridge_duplicate_state(bridge, new);
    622
    623	return new;
    624}
    625EXPORT_SYMBOL(drm_atomic_helper_bridge_duplicate_state);
    626
    627/**
    628 * drm_atomic_helper_bridge_destroy_state() - Destroy a bridge state object
    629 * @bridge: the bridge this state refers to
    630 * @state: bridge state to destroy
    631 *
    632 * Destroys a bridge state previously created by
    633 * &drm_atomic_helper_bridge_reset() or
    634 * &drm_atomic_helper_bridge_duplicate_state(). This helper is meant to be
    635 * used as a bridge &drm_bridge_funcs.atomic_destroy_state hook for bridges
    636 * that don't subclass the bridge state.
    637 */
    638void drm_atomic_helper_bridge_destroy_state(struct drm_bridge *bridge,
    639					    struct drm_bridge_state *state)
    640{
    641	kfree(state);
    642}
    643EXPORT_SYMBOL(drm_atomic_helper_bridge_destroy_state);
    644
    645/**
    646 * __drm_atomic_helper_bridge_reset() - Initialize a bridge state to its
    647 *					default
    648 * @bridge: the bridge this state refers to
    649 * @state: bridge state to initialize
    650 *
    651 * Initializes the bridge state to default values. This is meant to be called
    652 * by the bridge &drm_bridge_funcs.atomic_reset hook for bridges that subclass
    653 * the bridge state.
    654 */
    655void __drm_atomic_helper_bridge_reset(struct drm_bridge *bridge,
    656				      struct drm_bridge_state *state)
    657{
    658	memset(state, 0, sizeof(*state));
    659	state->bridge = bridge;
    660}
    661EXPORT_SYMBOL(__drm_atomic_helper_bridge_reset);
    662
    663/**
    664 * drm_atomic_helper_bridge_reset() - Allocate and initialize a bridge state
    665 *				      to its default
    666 * @bridge: the bridge this state refers to
    667 *
    668 * Allocates the bridge state and initializes it to default values. This helper
    669 * is meant to be used as a bridge &drm_bridge_funcs.atomic_reset hook for
    670 * bridges that don't subclass the bridge state.
    671 */
    672struct drm_bridge_state *
    673drm_atomic_helper_bridge_reset(struct drm_bridge *bridge)
    674{
    675	struct drm_bridge_state *bridge_state;
    676
    677	bridge_state = kzalloc(sizeof(*bridge_state), GFP_KERNEL);
    678	if (!bridge_state)
    679		return ERR_PTR(-ENOMEM);
    680
    681	__drm_atomic_helper_bridge_reset(bridge, bridge_state);
    682	return bridge_state;
    683}
    684EXPORT_SYMBOL(drm_atomic_helper_bridge_reset);