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Subject: Re: [PATCH v5 4/8] drm/omap: omap_plane: subclass drm_plane_state
To:     Neil Armstrong <narmstrong@baylibre.com>
Cc:     linux-omap@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, khilman@baylibre.com,
        Benoit Parrot <bparrot@ti.com>
References: <20210923070701.145377-1-narmstrong@baylibre.com>
 <20210923070701.145377-5-narmstrong@baylibre.com>
From:   Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Message-ID: <b9bb0e4b-26b8-72f0-937b-1a08145352d8@ideasonboard.com>
Date:   Tue, 12 Oct 2021 11:13:59 +0300
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On 23/09/2021 10:06, Neil Armstrong wrote:
> From: Benoit Parrot <bparrot@ti.com>
> 
> In preparation to add omap plane state specific extensions we need to
> subclass drm_plane_state and add the relevant helpers.
> 
> The addition of specific extension will be done separately.
> 
> Signed-off-by: Benoit Parrot <bparrot@ti.com>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
>   drivers/gpu/drm/omapdrm/omap_plane.c | 38 +++++++++++++++++++++++++---
>   1 file changed, 35 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/omap_plane.c b/drivers/gpu/drm/omapdrm/omap_plane.c
> index 0df5381cc015..bda794b4c915 100644
> --- a/drivers/gpu/drm/omapdrm/omap_plane.c
> +++ b/drivers/gpu/drm/omapdrm/omap_plane.c
> @@ -16,6 +16,13 @@
>    * plane funcs
>    */
>   
> +#define to_omap_plane_state(x) container_of(x, struct omap_plane_state, base)
> +
> +struct omap_plane_state {
> +	/* Must be first. */
> +	struct drm_plane_state base;
> +};
> +
>   #define to_omap_plane(x) container_of(x, struct omap_plane, base)
>   
>   struct omap_plane {
> @@ -207,11 +214,17 @@ void omap_plane_install_properties(struct drm_plane *plane,
>   static void omap_plane_reset(struct drm_plane *plane)
>   {
>   	struct omap_plane *omap_plane = to_omap_plane(plane);
> +	struct omap_plane_state *omap_state;
>   
> -	drm_atomic_helper_plane_reset(plane);
> -	if (!plane->state)
> +	if (plane->state)
> +		drm_atomic_helper_plane_destroy_state(plane, plane->state);
> +
> +	omap_state = kzalloc(sizeof(*omap_state), GFP_KERNEL);
> +	if (!omap_state)
>   		return;
>   
> +	__drm_atomic_helper_plane_reset(plane, &omap_state->base);
> +
>   	/*
>   	 * Set the zpos default depending on whether we are a primary or overlay
>   	 * plane.
> @@ -222,6 +235,25 @@ static void omap_plane_reset(struct drm_plane *plane)
>   	plane->state->color_range = DRM_COLOR_YCBCR_FULL_RANGE;
>   }
>   
> +static struct drm_plane_state *
> +omap_plane_atomic_duplicate_state(struct drm_plane *plane)
> +{
> +	struct omap_plane_state *state;
> +	struct omap_plane_state *copy;
> +
> +	if (WARN_ON(!plane->state))
> +		return NULL;
> +
> +	state = to_omap_plane_state(plane->state);
> +	copy = kmemdup(state, sizeof(*state), GFP_KERNEL);
> +	if (!copy)
> +		return NULL;
> +
> +	__drm_atomic_helper_plane_duplicate_state(plane, &copy->base);
> +
> +	return &copy->base;
> +}
> +

omap_crtc.c has similar, but slightly different, functions. I think it 
would be good to use the same style in omap_plane, or, if the approach 
above is better, change omap_crtc to match the style here.

  Tomi