[PATCH v4 4/5] drm/sun4i: Add support for plane alpha

[Paul Kocialkowski]

Hi,

On Tue, 2018-03-13 at 21:54 +0100, Maxime Ripard wrote:
> Our backend supports a per-plane alpha property. Support it through
> our new
> helper.

See one comment below. Otherwise, this is:
Reviewed-by: Paul Kocialkowski <paul.kocialkowski at bootlin.com>

> Reviewed-by: Chen-Yu Tsai <wens at csie.org>
> Signed-off-by: Maxime Ripard <maxime.ripard at bootlin.com>
> ---
>  drivers/gpu/drm/sun4i/sun4i_backend.c | 16 +++++++++++++---
>  drivers/gpu/drm/sun4i/sun4i_backend.h |  3 +++
>  drivers/gpu/drm/sun4i/sun4i_layer.c   |  2 ++
>  3 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c
> b/drivers/gpu/drm/sun4i/sun4i_backend.c
> index 092ade4ff6a5..98cd4a8a93ed 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_backend.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
> @@ -186,6 +186,15 @@ int sun4i_backend_update_layer_formats(struct
> sun4i_backend *backend,
>  	DRM_DEBUG_DRIVER("Switching display backend interlaced mode
> %s\n",
>  			 interlaced ? "on" : "off");
>  
> +	val = SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA(state->alpha >>
> 8);

Have you checked that the alpha value expected by the hardware does
match the "premultiplied" alpha blemding equation?

> +	if (state->alpha != DRM_BLEND_ALPHA_OPAQUE)
> +		val |= SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_EN;

Maybe insert a newline for improved readability here?

> +	regmap_update_bits(backend->engine.regs,
> +			   SUN4I_BACKEND_ATTCTL_REG0(layer),
> +			   SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_MAS
> K |
> +			   SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_EN,
> +			   val);
> +
>  	ret = sun4i_backend_drm_format_to_layer(fb->format->format,
> &val);
>  	if (ret) {
>  		DRM_DEBUG_DRIVER("Invalid format\n");
> @@ -359,7 +368,7 @@ static int sun4i_backend_atomic_check(struct
> sunxi_engine *engine,
>  		DRM_DEBUG_DRIVER("Plane FB format is %s\n",
>  				 drm_get_format_name(fb->format-
> >format,
>  						     &format_name));
> -		if (fb->format->has_alpha)
> +		if (fb->format->has_alpha || (plane_state->alpha !=
> DRM_BLEND_ALPHA_OPAQUE))
>  			num_alpha_planes++;
>  
>  		DRM_DEBUG_DRIVER("Plane zpos is %d\n",
> @@ -412,7 +421,8 @@ static int sun4i_backend_atomic_check(struct
> sunxi_engine *engine,
>  	}
>  
>  	/* We can't have an alpha plane at the lowest position */
> -	if (plane_states[0]->fb->format->has_alpha)
> +	if (plane_states[0]->fb->format->has_alpha ||
> +	    (plane_states[0]->alpha != DRM_BLEND_ALPHA_OPAQUE))
>  		return -EINVAL;
>  
>  	for (i = 1; i < num_planes; i++) {
> @@ -424,7 +434,7 @@ static int sun4i_backend_atomic_check(struct
> sunxi_engine *engine,
>  		 * The only alpha position is the lowest plane of the
>  		 * second pipe.
>  		 */
> -		if (fb->format->has_alpha)
> +		if (fb->format->has_alpha || (p_state->alpha !=
> DRM_BLEND_ALPHA_OPAQUE))
>  			current_pipe++;
>  
>  		s_state->pipe = current_pipe;
> diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.h
> b/drivers/gpu/drm/sun4i/sun4i_backend.h
> index 52e77591186a..03294d5dd1a2 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_backend.h
> +++ b/drivers/gpu/drm/sun4i/sun4i_backend.h
> @@ -68,11 +68,14 @@
>  #define SUN4I_BACKEND_CKMIN_REG			0x884
>  #define SUN4I_BACKEND_CKCFG_REG			0x888
>  #define SUN4I_BACKEND_ATTCTL_REG0(l)		(0x890 + (0x4 *
> (l)))
> +#define SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_MASK	GENMASK(31
> , 24)
> +#define SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA(x)		((x)
> << 24)
>  #define SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL_MASK	BIT(15)
>  #define SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL(x)		((x)
> << 15)
>  #define SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL_MASK	GENMASK(11,
> 10)
>  #define SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL(x)			
> ((x) << 10)
>  #define SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN		BIT(1)
> +#define SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_EN	BIT(0)
>  
>  #define SUN4I_BACKEND_ATTCTL_REG1(l)		(0x8a0 + (0x4 *
> (l)))
>  #define SUN4I_BACKEND_ATTCTL_REG1_LAY_HSCAFCT		GENMASK(
> 15, 14)
> diff --git a/drivers/gpu/drm/sun4i/sun4i_layer.c
> b/drivers/gpu/drm/sun4i/sun4i_layer.c
> index 33ad377569ec..cf7857b8ac5c 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_layer.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_layer.c
> @@ -37,6 +37,7 @@ static void sun4i_backend_layer_reset(struct
> drm_plane *plane)
>  	if (state) {
>  		plane->state = &state->state;
>  		plane->state->plane = plane;
> +		plane->state->alpha = DRM_BLEND_ALPHA_OPAQUE;
>  		plane->state->zpos = layer->id;
>  	}
>  }
> @@ -163,6 +164,7 @@ static struct sun4i_layer
> *sun4i_layer_init_one(struct drm_device *drm,
>  			     &sun4i_backend_layer_helper_funcs);
>  	layer->backend = backend;
>  
> +	drm_plane_create_alpha_property(&layer->plane);
>  	drm_plane_create_zpos_property(&layer->plane, 0, 0,
>  				       SUN4I_BACKEND_NUM_LAYERS - 1);
>  
-- 
Paul Kocialkowski, Bootlin (formerly Free Electrons)
Embedded Linux and kernel engineering
https://bootlin.com
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