text: /*
   * Copyright (C) 2016 Noralf Trønnes
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   */
  
  #include <drm/drmP.h>
  #include <drm/drm_atomic.h>
  #include <drm/drm_atomic_helper.h>
  #include <drm/drm_crtc_helper.h>
  #include <drm/drm_plane_helper.h>
  #include <drm/drm_simple_kms_helper.h>
  #include <linux/slab.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.
   */
  
  static const struct drm_encoder_funcs drm_simple_kms_encoder_funcs = {
  	.destroy = drm_encoder_cleanup,
  };
  
  static int drm_simple_kms_crtc_check(struct drm_crtc *crtc,
  				     struct drm_crtc_state *state)
  {
  	return drm_atomic_add_affected_planes(state->state, crtc);
  }
  
  static void drm_simple_kms_crtc_enable(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)
  		return;
  
  	pipe->funcs->enable(pipe, crtc->state);
  }
  
  static void drm_simple_kms_crtc_disable(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)
  		return;
  
  	pipe->funcs->disable(pipe);
  }
  
  static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
  	.atomic_check = drm_simple_kms_crtc_check,
  	.disable = drm_simple_kms_crtc_disable,
  	.enable = drm_simple_kms_crtc_enable,
  };
  
  static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
  	.reset = drm_atomic_helper_crtc_reset,
  	.destroy = drm_crtc_cleanup,
  	.set_config = drm_atomic_helper_set_config,
  	.page_flip = drm_atomic_helper_page_flip,
  	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
  	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
  };
  
  static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
  					struct drm_plane_state *plane_state)
  {
  	struct drm_rect clip = { 0 };
  	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_existing_crtc_state(plane_state->state,
  							&pipe->crtc);
  	if (crtc_state->enable != !!plane_state->crtc)
  		return -EINVAL; /* plane must match crtc enable state */
  
  	if (!crtc_state->enable)
  		return 0; /* nothing to check when disabling or disabled */
  
  	clip.x2 = crtc_state->adjusted_mode.hdisplay;
  	clip.y2 = crtc_state->adjusted_mode.vdisplay;
  
  	ret = drm_plane_helper_check_state(plane_state, &clip,
  					   DRM_PLANE_HELPER_NO_SCALING,
  					   DRM_PLANE_HELPER_NO_SCALING,
  					   false, true);
  	if (ret)
  		return ret;
  
  	if (!plane_state->visible)
  		return -EINVAL;
  
  	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_plane_state *pstate)
  {
  	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, 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)
  		return 0;
  
  	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 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 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_atomic_helper_plane_reset,
  	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
  	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
  };
  
  /**
   * 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);
  }
  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
   * @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,
  			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,
  				       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 = 1 << drm_crtc_index(crtc);
  	ret = drm_encoder_init(dev, encoder, &drm_simple_kms_encoder_funcs,
  			       DRM_MODE_ENCODER_NONE, NULL);
  	if (ret || !connector)
  		return ret;
  
  	return drm_mode_connector_attach_encoder(connector, encoder);
  }
  EXPORT_SYMBOL(drm_simple_display_pipe_init);
  
  MODULE_LICENSE("GPL");
  