drivers/gpu/drm/drm_simple_kms_helper.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (C) 2016 Noralf Trønnes
  */

 #include <linux/module.h>
 #include <linux/slab.h>

 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_gem_atomic_helper.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_simple_kms_helper.h>

 /**
  * DOC: overview
  *
  * This helper library provides helpers for drivers for simple display
  * hardware.
  *
  * drm_simple_display_pipe_init() initializes a simple display pipeline
  * which has only one full-screen scanout buffer feeding one output. The
  * pipeline is represented by &struct drm_simple_display_pipe and binds
  * together &drm_plane, &drm_crtc and &drm_encoder structures into one fixed
  * entity. Some flexibility for code reuse is provided through a separately
  * allocated &drm_connector object and supporting optional &drm_bridge
  * encoder drivers.
  *
  * Many drivers require only a very simple encoder that fulfills the minimum
  * requirements of the display pipeline and does not add additional
  * functionality. The function drm_simple_encoder_init() provides an
  * implementation of such an encoder.
  */

 static const struct drm_encoder_funcs drm_simple_encoder_funcs_cleanup = {
 	.destroy = drm_encoder_cleanup,
 };

 /**
  * drm_simple_encoder_init - Initialize a preallocated encoder with
  *                           basic functionality.
  * @dev: drm device
  * @encoder: the encoder to initialize
  * @encoder_type: user visible type of the encoder
  *
  * Initialises a preallocated encoder that has no further functionality.
  * Settings for possible CRTC and clones are left to their initial values.
  * The encoder will be cleaned up automatically as part of the mode-setting
  * cleanup.
  *
  * The caller of drm_simple_encoder_init() is responsible for freeing
  * the encoder's memory after the encoder has been cleaned up. At the
  * moment this only works reliably if the encoder data structure is
  * stored in the device structure. Free the encoder's memory as part of
  * the device release function.
  *
  * Note: consider using drmm_simple_encoder_alloc() instead of
  * drm_simple_encoder_init() to let the DRM managed resource infrastructure
  * take care of cleanup and deallocation.
  *
  * Returns:
  * Zero on success, error code on failure.
  */
 int drm_simple_encoder_init(struct drm_device *dev,
 			    struct drm_encoder *encoder,
 			    int encoder_type)
 {
 	return drm_encoder_init(dev, encoder,
 				&drm_simple_encoder_funcs_cleanup,
 				encoder_type, NULL);
 }
 EXPORT_SYMBOL(drm_simple_encoder_init);

 void *__drmm_simple_encoder_alloc(struct drm_device *dev, size_t size,
 				  size_t offset, int encoder_type)
 {
 	return __drmm_encoder_alloc(dev, size, offset, NULL, encoder_type,
 				    NULL);
 }
 EXPORT_SYMBOL(__drmm_simple_encoder_alloc);

 static enum drm_mode_status
 drm_simple_kms_crtc_mode_valid(struct drm_crtc *crtc,
 			       const struct drm_display_mode *mode)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 	if (!pipe->funcs || !pipe->funcs->mode_valid)
 		/* Anything goes */
 		return MODE_OK;

 	return pipe->funcs->mode_valid(pipe, mode);
 }

 static int drm_simple_kms_crtc_check(struct drm_crtc *crtc,
 				     struct drm_atomic_state *state)
 {
 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
 									  crtc);
 	bool has_primary = crtc_state->plane_mask &
 			   drm_plane_mask(crtc->primary);

 	/* We always want to have an active plane with an active CRTC */
 	if (has_primary != crtc_state->enable)
 		return -EINVAL;

 	return drm_atomic_add_affected_planes(state, crtc);
 }

 static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc,
 				       struct drm_atomic_state *state)
 {
 	struct drm_plane *plane;
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 	if (!pipe->funcs || !pipe->funcs->enable)
 		return;

 	plane = &pipe->plane;
 	pipe->funcs->enable(pipe, crtc->state, plane->state);
 }

 static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc,
 					struct drm_atomic_state *state)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 	if (!pipe->funcs || !pipe->funcs->disable)
 		return;

 	pipe->funcs->disable(pipe);
 }

 static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
 	.mode_valid = drm_simple_kms_crtc_mode_valid,
 	.atomic_check = drm_simple_kms_crtc_check,
 	.atomic_enable = drm_simple_kms_crtc_enable,
 	.atomic_disable = drm_simple_kms_crtc_disable,
 };

 static void drm_simple_kms_crtc_reset(struct drm_crtc *crtc)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 	if (!pipe->funcs || !pipe->funcs->reset_crtc)
 		return drm_atomic_helper_crtc_reset(crtc);

 	return pipe->funcs->reset_crtc(pipe);
 }

 static struct drm_crtc_state *drm_simple_kms_crtc_duplicate_state(struct drm_crtc *crtc)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 	if (!pipe->funcs || !pipe->funcs->duplicate_crtc_state)
 		return drm_atomic_helper_crtc_duplicate_state(crtc);

 	return pipe->funcs->duplicate_crtc_state(pipe);
 }

 static void drm_simple_kms_crtc_destroy_state(struct drm_crtc *crtc, struct drm_crtc_state *state)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 	if (!pipe->funcs || !pipe->funcs->destroy_crtc_state)
 		drm_atomic_helper_crtc_destroy_state(crtc, state);
 	else
 		pipe->funcs->destroy_crtc_state(pipe, state);
 }

 static int drm_simple_kms_crtc_enable_vblank(struct drm_crtc *crtc)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 	if (!pipe->funcs || !pipe->funcs->enable_vblank)
 		return 0;

 	return pipe->funcs->enable_vblank(pipe);
 }

 static void drm_simple_kms_crtc_disable_vblank(struct drm_crtc *crtc)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 	if (!pipe->funcs || !pipe->funcs->disable_vblank)
 		return;

 	pipe->funcs->disable_vblank(pipe);
 }

 static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
 	.reset = drm_simple_kms_crtc_reset,
 	.destroy = drm_crtc_cleanup,
 	.set_config = drm_atomic_helper_set_config,
 	.page_flip = drm_atomic_helper_page_flip,
 	.atomic_duplicate_state = drm_simple_kms_crtc_duplicate_state,
 	.atomic_destroy_state = drm_simple_kms_crtc_destroy_state,
 	.enable_vblank = drm_simple_kms_crtc_enable_vblank,
 	.disable_vblank = drm_simple_kms_crtc_disable_vblank,
 };

 static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
 					struct drm_atomic_state *state)
 {
 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state,
 									     plane);
 	struct drm_simple_display_pipe *pipe;
 	struct drm_crtc_state *crtc_state;
 	int ret;

 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 	crtc_state = drm_atomic_get_new_crtc_state(state,
 						   &pipe->crtc);

 	ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
 						  DRM_PLANE_HELPER_NO_SCALING,
 						  DRM_PLANE_HELPER_NO_SCALING,
 						  false, true);
 	if (ret)
 		return ret;

 	if (!plane_state->visible)
 		return 0;

 	if (!pipe->funcs || !pipe->funcs->check)
 		return 0;

 	return pipe->funcs->check(pipe, plane_state, crtc_state);
 }

 static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
 					struct drm_atomic_state *state)
 {
 	struct drm_plane_state *old_pstate = drm_atomic_get_old_plane_state(state,
 									    plane);
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 	if (!pipe->funcs || !pipe->funcs->update)
 		return;

 	pipe->funcs->update(pipe, old_pstate);
 }

 static int drm_simple_kms_plane_prepare_fb(struct drm_plane *plane,
 					   struct drm_plane_state *state)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 	if (!pipe->funcs || !pipe->funcs->prepare_fb) {
 		if (WARN_ON_ONCE(!drm_core_check_feature(plane->dev, DRIVER_GEM)))
 			return 0;

 		WARN_ON_ONCE(pipe->funcs && pipe->funcs->cleanup_fb);

 		return drm_gem_simple_display_pipe_prepare_fb(pipe, state);
 	}

 	return pipe->funcs->prepare_fb(pipe, state);
 }

 static void drm_simple_kms_plane_cleanup_fb(struct drm_plane *plane,
 					    struct drm_plane_state *state)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 	if (!pipe->funcs || !pipe->funcs->cleanup_fb)
 		return;

 	pipe->funcs->cleanup_fb(pipe, state);
 }

 static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane,
 						uint32_t format,
 						uint64_t modifier)
 {
 	return modifier == DRM_FORMAT_MOD_LINEAR;
 }

 static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
 	.prepare_fb = drm_simple_kms_plane_prepare_fb,
 	.cleanup_fb = drm_simple_kms_plane_cleanup_fb,
 	.atomic_check = drm_simple_kms_plane_atomic_check,
 	.atomic_update = drm_simple_kms_plane_atomic_update,
 };

 static void drm_simple_kms_plane_reset(struct drm_plane *plane)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 	if (!pipe->funcs || !pipe->funcs->reset_plane)
 		return drm_atomic_helper_plane_reset(plane);

 	return pipe->funcs->reset_plane(pipe);
 }

 static struct drm_plane_state *drm_simple_kms_plane_duplicate_state(struct drm_plane *plane)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 	if (!pipe->funcs || !pipe->funcs->duplicate_plane_state)
 		return drm_atomic_helper_plane_duplicate_state(plane);

 	return pipe->funcs->duplicate_plane_state(pipe);
 }

 static void drm_simple_kms_plane_destroy_state(struct drm_plane *plane,
 					       struct drm_plane_state *state)
 {
 	struct drm_simple_display_pipe *pipe;

 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 	if (!pipe->funcs || !pipe->funcs->destroy_plane_state)
 		drm_atomic_helper_plane_destroy_state(plane, state);
 	else
 		pipe->funcs->destroy_plane_state(pipe, state);
 }

 static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
 	.update_plane		= drm_atomic_helper_update_plane,
 	.disable_plane		= drm_atomic_helper_disable_plane,
 	.destroy		= drm_plane_cleanup,
 	.reset			= drm_simple_kms_plane_reset,
 	.atomic_duplicate_state	= drm_simple_kms_plane_duplicate_state,
 	.atomic_destroy_state	= drm_simple_kms_plane_destroy_state,
 	.format_mod_supported   = drm_simple_kms_format_mod_supported,
 };

 /**
  * drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
  * @pipe: simple display pipe object
  * @bridge: bridge to attach
  *
  * Makes it possible to still use the drm_simple_display_pipe helpers when
  * a DRM bridge has to be used.
  *
  * Note that you probably want to initialize the pipe by passing a NULL
  * connector to drm_simple_display_pipe_init().
  *
  * Returns:
  * Zero on success, negative error code on failure.
  */
 int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
 					  struct drm_bridge *bridge)
 {
 	return drm_bridge_attach(&pipe->encoder, bridge, NULL, 0);
 }
 EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);

 /**
  * drm_simple_display_pipe_init - Initialize a simple display pipeline
  * @dev: DRM device
  * @pipe: simple display pipe object to initialize
  * @funcs: callbacks for the display pipe (optional)
  * @formats: array of supported formats (DRM_FORMAT\_\*)
  * @format_count: number of elements in @formats
  * @format_modifiers: array of formats modifiers
  * @connector: connector to attach and register (optional)
  *
  * Sets up a display pipeline which consist of a really simple
  * plane-crtc-encoder pipe.
  *
  * If a connector is supplied, the pipe will be coupled with the provided
  * connector. You may supply a NULL connector when using drm bridges, that
  * handle connectors themselves (see drm_simple_display_pipe_attach_bridge()).
  *
  * Teardown of a simple display pipe is all handled automatically by the drm
  * core through calling drm_mode_config_cleanup(). Drivers afterwards need to
  * release the memory for the structure themselves.
  *
  * Returns:
  * Zero on success, negative error code on failure.
  */
 int drm_simple_display_pipe_init(struct drm_device *dev,
 			struct drm_simple_display_pipe *pipe,
 			const struct drm_simple_display_pipe_funcs *funcs,
 			const uint32_t *formats, unsigned int format_count,
 			const uint64_t *format_modifiers,
 			struct drm_connector *connector)
 {
 	struct drm_encoder *encoder = &pipe->encoder;
 	struct drm_plane *plane = &pipe->plane;
 	struct drm_crtc *crtc = &pipe->crtc;
 	int ret;

 	pipe->connector = connector;
 	pipe->funcs = funcs;

 	drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
 	ret = drm_universal_plane_init(dev, plane, 0,
 				       &drm_simple_kms_plane_funcs,
 				       formats, format_count,
 				       format_modifiers,
 				       DRM_PLANE_TYPE_PRIMARY, NULL);
 	if (ret)
 		return ret;

 	drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
 	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
 					&drm_simple_kms_crtc_funcs, NULL);
 	if (ret)
 		return ret;

 	encoder->possible_crtcs = drm_crtc_mask(crtc);
 	ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
 	if (ret || !connector)
 		return ret;

 	return drm_connector_attach_encoder(connector, encoder);
 }
 EXPORT_SYMBOL(drm_simple_display_pipe_init);

 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Copyright (C) 2016 Noralf Trønnes
	*/

	#include <linux/module.h>
	#include <linux/slab.h>

	#include <drm/drm_atomic.h>
	#include <drm/drm_atomic_helper.h>
	#include <drm/drm_bridge.h>
	#include <drm/drm_drv.h>
	#include <drm/drm_gem_atomic_helper.h>
	#include <drm/drm_managed.h>
	#include <drm/drm_plane_helper.h>
	#include <drm/drm_probe_helper.h>
	#include <drm/drm_simple_kms_helper.h>

	/**
	* DOC: overview
	*
	* This helper library provides helpers for drivers for simple display
	* hardware.
	*
	* drm_simple_display_pipe_init() initializes a simple display pipeline
	* which has only one full-screen scanout buffer feeding one output. The
	* pipeline is represented by &struct drm_simple_display_pipe and binds
	* together &drm_plane, &drm_crtc and &drm_encoder structures into one fixed
	* entity. Some flexibility for code reuse is provided through a separately
	* allocated &drm_connector object and supporting optional &drm_bridge
	* encoder drivers.
	*
	* Many drivers require only a very simple encoder that fulfills the minimum
	* requirements of the display pipeline and does not add additional
	* functionality. The function drm_simple_encoder_init() provides an
	* implementation of such an encoder.
	*/

	static const struct drm_encoder_funcs drm_simple_encoder_funcs_cleanup = {
	.destroy = drm_encoder_cleanup,
	};

	/**
	* drm_simple_encoder_init - Initialize a preallocated encoder with
	* basic functionality.
	* @dev: drm device
	* @encoder: the encoder to initialize
	* @encoder_type: user visible type of the encoder
	*
	* Initialises a preallocated encoder that has no further functionality.
	* Settings for possible CRTC and clones are left to their initial values.
	* The encoder will be cleaned up automatically as part of the mode-setting
	* cleanup.
	*
	* The caller of drm_simple_encoder_init() is responsible for freeing
	* the encoder's memory after the encoder has been cleaned up. At the
	* moment this only works reliably if the encoder data structure is
	* stored in the device structure. Free the encoder's memory as part of
	* the device release function.
	*
	* Note: consider using drmm_simple_encoder_alloc() instead of
	* drm_simple_encoder_init() to let the DRM managed resource infrastructure
	* take care of cleanup and deallocation.
	*
	* Returns:
	* Zero on success, error code on failure.
	*/
	int drm_simple_encoder_init(struct drm_device *dev,
	struct drm_encoder *encoder,
	int encoder_type)
	{
	return drm_encoder_init(dev, encoder,
	&drm_simple_encoder_funcs_cleanup,
	encoder_type, NULL);
	}
	EXPORT_SYMBOL(drm_simple_encoder_init);

	void __drmm_simple_encoder_alloc(struct drm_device dev, size_t size,
	size_t offset, int encoder_type)
	{
	return __drmm_encoder_alloc(dev, size, offset, NULL, encoder_type,
	NULL);
	}
	EXPORT_SYMBOL(__drmm_simple_encoder_alloc);

	static enum drm_mode_status
	drm_simple_kms_crtc_mode_valid(struct drm_crtc *crtc,
	const struct drm_display_mode *mode)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
	if (!pipe->funcs \|\| !pipe->funcs->mode_valid)
	/* Anything goes */
	return MODE_OK;

	return pipe->funcs->mode_valid(pipe, mode);
	}

	static int drm_simple_kms_crtc_check(struct drm_crtc *crtc,
	struct drm_atomic_state *state)
	{
	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
	crtc);
	bool has_primary = crtc_state->plane_mask &
	drm_plane_mask(crtc->primary);

	/* We always want to have an active plane with an active CRTC */
	if (has_primary != crtc_state->enable)
	return -EINVAL;

	return drm_atomic_add_affected_planes(state, crtc);
	}

	static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc,
	struct drm_atomic_state *state)
	{
	struct drm_plane *plane;
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
	if (!pipe->funcs \|\| !pipe->funcs->enable)
	return;

	plane = &pipe->plane;
	pipe->funcs->enable(pipe, crtc->state, plane->state);
	}

	static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc,
	struct drm_atomic_state *state)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
	if (!pipe->funcs \|\| !pipe->funcs->disable)
	return;

	pipe->funcs->disable(pipe);
	}

	static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
	.mode_valid = drm_simple_kms_crtc_mode_valid,
	.atomic_check = drm_simple_kms_crtc_check,
	.atomic_enable = drm_simple_kms_crtc_enable,
	.atomic_disable = drm_simple_kms_crtc_disable,
	};

	static void drm_simple_kms_crtc_reset(struct drm_crtc *crtc)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
	if (!pipe->funcs \|\| !pipe->funcs->reset_crtc)
	return drm_atomic_helper_crtc_reset(crtc);

	return pipe->funcs->reset_crtc(pipe);
	}

	static struct drm_crtc_state drm_simple_kms_crtc_duplicate_state(struct drm_crtc crtc)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
	if (!pipe->funcs \|\| !pipe->funcs->duplicate_crtc_state)
	return drm_atomic_helper_crtc_duplicate_state(crtc);

	return pipe->funcs->duplicate_crtc_state(pipe);
	}

	static void drm_simple_kms_crtc_destroy_state(struct drm_crtc crtc, struct drm_crtc_state state)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
	if (!pipe->funcs \|\| !pipe->funcs->destroy_crtc_state)
	drm_atomic_helper_crtc_destroy_state(crtc, state);
	else
	pipe->funcs->destroy_crtc_state(pipe, state);
	}

	static int drm_simple_kms_crtc_enable_vblank(struct drm_crtc *crtc)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
	if (!pipe->funcs \|\| !pipe->funcs->enable_vblank)
	return 0;

	return pipe->funcs->enable_vblank(pipe);
	}

	static void drm_simple_kms_crtc_disable_vblank(struct drm_crtc *crtc)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
	if (!pipe->funcs \|\| !pipe->funcs->disable_vblank)
	return;

	pipe->funcs->disable_vblank(pipe);
	}

	static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
	.reset = drm_simple_kms_crtc_reset,
	.destroy = drm_crtc_cleanup,
	.set_config = drm_atomic_helper_set_config,
	.page_flip = drm_atomic_helper_page_flip,
	.atomic_duplicate_state = drm_simple_kms_crtc_duplicate_state,
	.atomic_destroy_state = drm_simple_kms_crtc_destroy_state,
	.enable_vblank = drm_simple_kms_crtc_enable_vblank,
	.disable_vblank = drm_simple_kms_crtc_disable_vblank,
	};

	static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
	struct drm_atomic_state *state)
	{
	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state,
	plane);
	struct drm_simple_display_pipe *pipe;
	struct drm_crtc_state *crtc_state;
	int ret;

	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
	crtc_state = drm_atomic_get_new_crtc_state(state,
	&pipe->crtc);

	ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
	DRM_PLANE_HELPER_NO_SCALING,
	DRM_PLANE_HELPER_NO_SCALING,
	false, true);
	if (ret)
	return ret;

	if (!plane_state->visible)
	return 0;

	if (!pipe->funcs \|\| !pipe->funcs->check)
	return 0;

	return pipe->funcs->check(pipe, plane_state, crtc_state);
	}

	static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
	struct drm_atomic_state *state)
	{
	struct drm_plane_state *old_pstate = drm_atomic_get_old_plane_state(state,
	plane);
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
	if (!pipe->funcs \|\| !pipe->funcs->update)
	return;

	pipe->funcs->update(pipe, old_pstate);
	}

	static int drm_simple_kms_plane_prepare_fb(struct drm_plane *plane,
	struct drm_plane_state *state)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
	if (!pipe->funcs \|\| !pipe->funcs->prepare_fb) {
	if (WARN_ON_ONCE(!drm_core_check_feature(plane->dev, DRIVER_GEM)))
	return 0;

	WARN_ON_ONCE(pipe->funcs && pipe->funcs->cleanup_fb);

	return drm_gem_simple_display_pipe_prepare_fb(pipe, state);
	}

	return pipe->funcs->prepare_fb(pipe, state);
	}

	static void drm_simple_kms_plane_cleanup_fb(struct drm_plane *plane,
	struct drm_plane_state *state)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
	if (!pipe->funcs \|\| !pipe->funcs->cleanup_fb)
	return;

	pipe->funcs->cleanup_fb(pipe, state);
	}

	static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane,
	uint32_t format,
	uint64_t modifier)
	{
	return modifier == DRM_FORMAT_MOD_LINEAR;
	}

	static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
	.prepare_fb = drm_simple_kms_plane_prepare_fb,
	.cleanup_fb = drm_simple_kms_plane_cleanup_fb,
	.atomic_check = drm_simple_kms_plane_atomic_check,
	.atomic_update = drm_simple_kms_plane_atomic_update,
	};

	static void drm_simple_kms_plane_reset(struct drm_plane *plane)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
	if (!pipe->funcs \|\| !pipe->funcs->reset_plane)
	return drm_atomic_helper_plane_reset(plane);

	return pipe->funcs->reset_plane(pipe);
	}

	static struct drm_plane_state drm_simple_kms_plane_duplicate_state(struct drm_plane plane)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
	if (!pipe->funcs \|\| !pipe->funcs->duplicate_plane_state)
	return drm_atomic_helper_plane_duplicate_state(plane);

	return pipe->funcs->duplicate_plane_state(pipe);
	}

	static void drm_simple_kms_plane_destroy_state(struct drm_plane *plane,
	struct drm_plane_state *state)
	{
	struct drm_simple_display_pipe *pipe;

	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
	if (!pipe->funcs \|\| !pipe->funcs->destroy_plane_state)
	drm_atomic_helper_plane_destroy_state(plane, state);
	else
	pipe->funcs->destroy_plane_state(pipe, state);
	}

	static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
	.update_plane = drm_atomic_helper_update_plane,
	.disable_plane = drm_atomic_helper_disable_plane,
	.destroy = drm_plane_cleanup,
	.reset = drm_simple_kms_plane_reset,
	.atomic_duplicate_state = drm_simple_kms_plane_duplicate_state,
	.atomic_destroy_state = drm_simple_kms_plane_destroy_state,
	.format_mod_supported = drm_simple_kms_format_mod_supported,
	};

	/**
	* drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
	* @pipe: simple display pipe object
	* @bridge: bridge to attach
	*
	* Makes it possible to still use the drm_simple_display_pipe helpers when
	* a DRM bridge has to be used.
	*
	* Note that you probably want to initialize the pipe by passing a NULL
	* connector to drm_simple_display_pipe_init().
	*
	* Returns:
	* Zero on success, negative error code on failure.
	*/
	int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
	struct drm_bridge *bridge)
	{
	return drm_bridge_attach(&pipe->encoder, bridge, NULL, 0);
	}
	EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);

	/**
	* drm_simple_display_pipe_init - Initialize a simple display pipeline
	* @dev: DRM device
	* @pipe: simple display pipe object to initialize
	* @funcs: callbacks for the display pipe (optional)
	* @formats: array of supported formats (DRM_FORMAT\_\*)
	* @format_count: number of elements in @formats
	* @format_modifiers: array of formats modifiers
	* @connector: connector to attach and register (optional)
	*
	* Sets up a display pipeline which consist of a really simple
	* plane-crtc-encoder pipe.
	*
	* If a connector is supplied, the pipe will be coupled with the provided
	* connector. You may supply a NULL connector when using drm bridges, that
	* handle connectors themselves (see drm_simple_display_pipe_attach_bridge()).
	*
	* Teardown of a simple display pipe is all handled automatically by the drm
	* core through calling drm_mode_config_cleanup(). Drivers afterwards need to
	* release the memory for the structure themselves.
	*
	* Returns:
	* Zero on success, negative error code on failure.
	*/
	int drm_simple_display_pipe_init(struct drm_device *dev,
	struct drm_simple_display_pipe *pipe,
	const struct drm_simple_display_pipe_funcs *funcs,
	const uint32_t *formats, unsigned int format_count,
	const uint64_t *format_modifiers,
	struct drm_connector *connector)
	{
	struct drm_encoder *encoder = &pipe->encoder;
	struct drm_plane *plane = &pipe->plane;
	struct drm_crtc *crtc = &pipe->crtc;
	int ret;

	pipe->connector = connector;
	pipe->funcs = funcs;

	drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
	ret = drm_universal_plane_init(dev, plane, 0,
	&drm_simple_kms_plane_funcs,
	formats, format_count,
	format_modifiers,
	DRM_PLANE_TYPE_PRIMARY, NULL);
	if (ret)
	return ret;

	drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
	&drm_simple_kms_crtc_funcs, NULL);
	if (ret)
	return ret;

	encoder->possible_crtcs = drm_crtc_mask(crtc);
	ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
	if (ret \|\| !connector)
	return ret;

	return drm_connector_attach_encoder(connector, encoder);
	}
	EXPORT_SYMBOL(drm_simple_display_pipe_init);

	MODULE_LICENSE("GPL");