[PATCH RFC 06/15] drm/vkms: Introduce plane configuration

[José Expósito]

> The current vkms driver only allows the usage of one primary, eight
> overlays and one cursor plane. This new configuration structure aims to
> make the configuration more flexible.
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx>
> ---
>  drivers/gpu/drm/vkms/vkms_config.c | 90 ++++++++++++++++++++++++++++++++++++--
>  drivers/gpu/drm/vkms/vkms_config.h | 44 +++++++++++++++++--
>  drivers/gpu/drm/vkms/vkms_drv.c    | 33 +++++---------
>  drivers/gpu/drm/vkms/vkms_plane.c  |  4 +-
>  drivers/gpu/drm/vkms/vkms_plane.h  |  3 +-
>  5 files changed, 141 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
> index 27b49a2ad9c8..b1c6160d350f 100644
> --- a/drivers/gpu/drm/vkms/vkms_config.c
> +++ b/drivers/gpu/drm/vkms/vkms_config.c
> @@ -13,32 +13,111 @@ struct vkms_config *vkms_config_create(void)
>  	if (!config)
>  		return ERR_PTR(-ENOMEM);
>  
> +	INIT_LIST_HEAD(&config->planes);
> +
>  	return config;
>  }
>  
>  struct vkms_config *vkms_config_alloc_default(bool enable_writeback, bool enable_overlay,
>  					      bool enable_cursor)
>  {
> +	struct vkms_config_plane *plane;
>  	struct vkms_config *vkms_config = vkms_config_create();
>  
>  	if (IS_ERR(vkms_config))
>  		return vkms_config;
>  
>  	vkms_config->writeback = enable_writeback;
> -	vkms_config->overlay = enable_overlay;
> -	vkms_config->cursor = enable_cursor;
> +
> +	plane = vkms_config_create_plane(vkms_config);
> +	if (!plane)
> +		goto err_alloc;
> +
> +	plane->type = DRM_PLANE_TYPE_PRIMARY;

Since all planes need to have a type, I think it'd make sense
to make "type" a param of vkms_config_create_plane().

> +
> +	if (enable_overlay) {
> +		for (int i = 0; i < NUM_OVERLAY_PLANES; i++) {
> +			plane = vkms_config_create_plane(vkms_config);
> +			if (!plane)
> +				goto err_alloc;
> +			plane->type = DRM_PLANE_TYPE_OVERLAY;
> +		}
> +	}
> +	if (enable_cursor) {
> +		plane = vkms_config_create_plane(vkms_config);
> +		if (!plane)
> +			goto err_alloc;
> +		plane->type = DRM_PLANE_TYPE_CURSOR;
> +	}
>  
>  	return vkms_config;
> +err_alloc:
> +	vkms_config_destroy(vkms_config);
> +	return ERR_PTR(-ENOMEM);
>  }
>  
> +struct vkms_config_plane *vkms_config_create_plane(struct vkms_config *vkms_config)
> +{
> +	if (!vkms_config)
> +		return NULL;
> +
> +	struct vkms_config_plane *vkms_config_overlay = kzalloc(sizeof(*vkms_config_overlay),
> +								GFP_KERNEL);

Nit: I guess the variable is named "vkms_config_overlay" due to a rebase.
As "struct vkms_config_plane" is used to configure any plane, it'd be
great to rename the variable to reflect it.

> +
> +	if (!vkms_config_overlay)
> +		return NULL;
> +
> +	vkms_config_overlay->type = DRM_PLANE_TYPE_OVERLAY;
> +
> +	list_add(&vkms_config_overlay->link, &vkms_config->planes);
> +
> +	return vkms_config_overlay;
> +}
> +
> +void vkms_config_delete_plane(struct vkms_config_plane *vkms_config_overlay)
> +{
> +	if (!vkms_config_overlay)
> +		return;
> +	list_del(&vkms_config_overlay->link);
> +	kfree(vkms_config_overlay);
> +}
>  
>  void vkms_config_destroy(struct vkms_config *config)
>  {
> +	struct vkms_config_plane *vkms_config_plane, *tmp_plane;
> +
> +	list_for_each_entry_safe(vkms_config_plane, tmp_plane, &config->planes, link) {
> +		vkms_config_delete_plane(vkms_config_plane);
> +	}

You can drop the extra curly brackets here.

> +
>  	kfree(config);
>  }
>  
>  bool vkms_config_is_valid(struct vkms_config *config)
>  {
> +	struct vkms_config_plane *config_plane;
> +
> +	bool has_cursor = false;
> +	bool has_primary = false;
> +
> +	list_for_each_entry(config_plane, &config->planes, link) {
> +		if (config_plane->type == DRM_PLANE_TYPE_PRIMARY) {
> +			// Multiple primary planes for only one CRTC
> +			if (has_primary)
> +				return false;
> +			has_primary = true;
> +		}
> +		if (config_plane->type == DRM_PLANE_TYPE_CURSOR) {
> +			// Multiple cursor planes for only one CRTC
> +			if (has_cursor)
> +				return false;
> +			has_cursor = true;
> +		}
> +	}
> +
> +	if (!has_primary)
> +		return false;
> +
>  	return true;
>  }
>  
> @@ -47,10 +126,13 @@ static int vkms_config_show(struct seq_file *m, void *data)
>  	struct drm_debugfs_entry *entry = m->private;
>  	struct drm_device *dev = entry->dev;
>  	struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
> +	struct vkms_config_plane *config_plane;
>  
>  	seq_printf(m, "writeback=%d\n", vkmsdev->config->writeback);
> -	seq_printf(m, "cursor=%d\n", vkmsdev->config->cursor);
> -	seq_printf(m, "overlay=%d\n", vkmsdev->config->overlay);
> +	list_for_each_entry(config_plane, &vkmsdev->config->planes, link) {
> +		seq_puts(m, "plane:\n");
> +		seq_printf(m, "\ttype: %d\n", config_plane->type);
> +	}
>  
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
> index 50c3b021a66b..77c1c3934189 100644
> --- a/drivers/gpu/drm/vkms/vkms_config.h
> +++ b/drivers/gpu/drm/vkms/vkms_config.h
> @@ -10,15 +10,34 @@
>   * struct vkms_config - General configuration for VKMS driver
>   *
>   * @writeback: If true, a writeback buffer can be attached to the CRTC
> - * @cursor: If true, a cursor plane is created in the VKMS device
> - * @overlay: If true, NUM_OVERLAY_PLANES will be created for the VKMS device
> + * @planes: List of planes configured for this device. They are created by the function
> + *          vkms_config_create_plane().
>   * @dev: Used to store the current vkms device. Only set when the device is instancied.
>   */
>  struct vkms_config {
>  	bool writeback;
> -	bool cursor;
> -	bool overlay;
>  	struct vkms_device *dev;
> +
> +	struct list_head planes;
> +};
> +
> +/**
> + * struct vkms_config_plane
> + *
> + * @link: Link to the others planes
> + * @type: Type of the plane. The creator of configuration needs to ensures that at least one
> + *        plane is primary.
> + * @plane: Internal usage. This pointer should never be considered as valid. It can be used to
> + *         store a temporary reference to a vkms plane during device creation. This pointer is
> + *         not managed by the configuration and must be managed by other means.
> + */
> +struct vkms_config_plane {
> +	struct list_head link;
> +
> +	enum drm_plane_type type;
> +
> +	/* Internal usage */
> +	struct vkms_plane *plane;
>  };
>  
>  /**
> @@ -42,6 +61,23 @@ void vkms_config_destroy(struct vkms_config *config);
>   */
>  bool vkms_config_is_valid(struct vkms_config *vkms_config);
>  
> +/**
> + * vkms_config_create_plane() - Create a plane configuration
> + *
> + * This will allocate and add a new plane to @vkms_config. This plane will have by default the
> + * maximum supported values.
> + * @vkms_config: Configuration where to insert new plane
> + */
> +struct vkms_config_plane *vkms_config_create_plane(struct vkms_config *vkms_config);
> +
> +/**
> + * vkms_config_delete_plane() - Remove a plane configuration and frees its memory
> + *
> + * This will delete a plane configuration from the parent configuration. This will NOT
> + * cleanup and frees the vkms_plane that can be stored in @vkms_config_plane.
> + * @vkms_config_plane: Plane configuration to cleanup
> + */
> +void vkms_config_delete_plane(struct vkms_config_plane *vkms_config_plane);
>  
>  /**
>   * vkms_config_alloc_default() - Allocate the configuration for the default device
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> index af237daa3c5c..403006a0bb61 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.c
> +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> @@ -153,38 +153,27 @@ static const struct drm_connector_helper_funcs vkms_conn_helper_funcs = {
>  
>  static int vkms_output_init(struct vkms_device *vkmsdev)
>  {
> +	struct vkms_config_plane *config_plane;
>  	struct drm_device *dev = &vkmsdev->drm;
>  	struct drm_connector *connector;
>  	struct drm_encoder *encoder;
>  	struct vkms_crtc *crtc;
>  	struct drm_plane *plane;
> -	struct vkms_plane *primary, *cursor, *overlay = NULL;
> +	struct vkms_plane *primary, *cursor = NULL;
>  	int ret;
>  	int writeback;
> -	unsigned int n;
>  
> -	/*
> -	 * Initialize used plane. One primary plane is required to perform the composition.
> -	 *
> -	 * The overlay and cursor planes are not mandatory, but can be used to perform complex
> -	 * composition.
> -	 */
> -	primary = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_PRIMARY);
> -	if (IS_ERR(primary))
> -		return PTR_ERR(primary);
> -
> -	if (vkmsdev->config->overlay) {
> -		for (n = 0; n < NUM_OVERLAY_PLANES; n++) {
> -			overlay = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_OVERLAY);
> -			if (IS_ERR(overlay))
> -				return PTR_ERR(overlay);
> +	list_for_each_entry(config_plane, &vkmsdev->config->planes, link) {
> +		config_plane->plane = vkms_plane_init(vkmsdev, config_plane);
> +		if (IS_ERR(config_plane->plane)) {
> +			ret = PTR_ERR(config_plane->plane);
> +			return ret;
>  		}
> -	}
>  
> -	if (vkmsdev->config->cursor) {
> -		cursor = vkms_plane_init(vkmsdev, DRM_PLANE_TYPE_CURSOR);
> -		if (IS_ERR(cursor))
> -			return PTR_ERR(cursor);
> +		if (config_plane->type == DRM_PLANE_TYPE_PRIMARY)
> +			primary = config_plane->plane;
> +		else if (config_plane->type == DRM_PLANE_TYPE_CURSOR)
> +			cursor = config_plane->plane;
>  	}
>  
>  	/* [1]: Initialize the crtc component */
> diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
> index b5740c27180b..dc9bccf60071 100644
> --- a/drivers/gpu/drm/vkms/vkms_plane.c
> +++ b/drivers/gpu/drm/vkms/vkms_plane.c
> @@ -223,7 +223,7 @@ static const struct drm_plane_helper_funcs vkms_plane_helper_funcs = {
>  };
>  
>  struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
> -				   enum drm_plane_type type)
> +				   struct vkms_config_plane *config)
>  {
>  	struct drm_device *dev = &vkmsdev->drm;
>  	struct vkms_plane *plane;
> @@ -231,7 +231,7 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
>  	plane = drmm_universal_plane_alloc(dev, struct vkms_plane, base, 0,
>  					   &vkms_plane_funcs,
>  					   vkms_formats, ARRAY_SIZE(vkms_formats),
> -					   NULL, type, NULL);
> +					   NULL, config->type, NULL);
>  	if (IS_ERR(plane))
>  		return plane;
>  
> diff --git a/drivers/gpu/drm/vkms/vkms_plane.h b/drivers/gpu/drm/vkms/vkms_plane.h
> index 95b2428331b8..82049966ee7e 100644
> --- a/drivers/gpu/drm/vkms/vkms_plane.h
> +++ b/drivers/gpu/drm/vkms/vkms_plane.h
> @@ -9,6 +9,7 @@
>  #include <linux/iosys-map.h>
>  
>  #include "vkms_formats.h"
> +#include "vkms_config.h"
>  
>  struct vkms_plane {
>  	struct drm_plane base;
> @@ -54,7 +55,7 @@ struct vkms_frame_info {
>   * @type: type of plane to initialize
>   */
>  struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
> -				   enum drm_plane_type type);
> +				   struct vkms_config_plane *config);
>  
>  #define drm_plane_state_to_vkms_plane_state(target) \
>  	container_of(target, struct vkms_plane_state, base.base)
>