Re: [PATCH] drm/stm: ltdc: add support of the dynamic z-order

[Philippe CORNU <philippe.cornu@foss.st.com>]

On 6/3/22 15:44, Yannick Fertre wrote:
> Zpos property is immutable for all hardware versions except the last
> version (0x40100) which support the blending order feature
> (dynamic z-order).
> 
> Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
> ---
>   drivers/gpu/drm/stm/drv.c  |  1 +
>   drivers/gpu/drm/stm/ltdc.c | 23 ++++++++++++++++++++---
>   drivers/gpu/drm/stm/ltdc.h |  1 +
>   3 files changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/stm/drv.c b/drivers/gpu/drm/stm/drv.c
> index 0da7cce2a1a2..c63945dc2260 100644
> --- a/drivers/gpu/drm/stm/drv.c
> +++ b/drivers/gpu/drm/stm/drv.c
> @@ -95,6 +95,7 @@ static int drv_load(struct drm_device *ddev)
>   	ddev->mode_config.max_width = STM_MAX_FB_WIDTH;
>   	ddev->mode_config.max_height = STM_MAX_FB_HEIGHT;
>   	ddev->mode_config.funcs = &drv_mode_config_funcs;
> +	ddev->mode_config.normalize_zpos = true;
>   
>   	ret = ltdc_load(ddev);
>   	if (ret)
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> index 6a9f613839b5..00a6bc1b1d7c 100644
> --- a/drivers/gpu/drm/stm/ltdc.c
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -194,6 +194,7 @@
>   
>   #define LXBFCR_BF2	GENMASK(2, 0)	/* Blending Factor 2 */
>   #define LXBFCR_BF1	GENMASK(10, 8)	/* Blending Factor 1 */
> +#define LXBFCR_BOR	GENMASK(18, 16) /* Blending ORder */
>   
>   #define LXCFBLR_CFBLL	GENMASK(12, 0)	/* Color Frame Buffer Line Length */
>   #define LXCFBLR_CFBP	GENMASK(28, 16)	/* Color Frame Buffer Pitch in bytes */
> @@ -1309,7 +1310,14 @@ static void ltdc_plane_atomic_update(struct drm_plane *plane,
>   	    plane->type != DRM_PLANE_TYPE_PRIMARY)
>   		val = BF1_PAXCA | BF2_1PAXCA;
>   
> -	regmap_write_bits(ldev->regmap, LTDC_L1BFCR + lofs, LXBFCR_BF2 | LXBFCR_BF1, val);
> +	if (ldev->caps.dynamic_zorder) {
> +		val |= (newstate->normalized_zpos << 16);
> +		regmap_write_bits(ldev->regmap, LTDC_L1BFCR + lofs,
> +				  LXBFCR_BF2 | LXBFCR_BF1 | LXBFCR_BOR, val);
> +	} else {
> +		regmap_write_bits(ldev->regmap, LTDC_L1BFCR + lofs,
> +				  LXBFCR_BF2 | LXBFCR_BF1, val);
> +	}
>   
>   	/* Configures the frame buffer line number */
>   	line_number = y1 - y0 + 1;
> @@ -1578,7 +1586,10 @@ static int ltdc_crtc_init(struct drm_device *ddev, struct drm_crtc *crtc)
>   		return -EINVAL;
>   	}
>   
> -	drm_plane_create_zpos_immutable_property(primary, 0);
> +	if (ldev->caps.dynamic_zorder)
> +		drm_plane_create_zpos_property(primary, 0, 0, ldev->caps.nb_layers - 1);
> +	else
> +		drm_plane_create_zpos_immutable_property(primary, 0);
>   
>   	/* Init CRTC according to its hardware features */
>   	if (ldev->caps.crc)
> @@ -1607,7 +1618,10 @@ static int ltdc_crtc_init(struct drm_device *ddev, struct drm_crtc *crtc)
>   			DRM_ERROR("Can not create overlay plane %d\n", i);
>   			goto cleanup;
>   		}
> -		drm_plane_create_zpos_immutable_property(overlay, i);
> +		if (ldev->caps.dynamic_zorder)
> +			drm_plane_create_zpos_property(overlay, i, 0, ldev->caps.nb_layers - 1);
> +		else
> +			drm_plane_create_zpos_immutable_property(overlay, i);
>   	}
>   
>   	return 0;
> @@ -1737,6 +1751,7 @@ static int ltdc_get_caps(struct drm_device *ddev)
>   		ldev->caps.ycbcr_output = false;
>   		ldev->caps.plane_reg_shadow = false;
>   		ldev->caps.crc = false;
> +		ldev->caps.dynamic_zorder = false;
>   		break;
>   	case HWVER_20101:
>   		ldev->caps.layer_ofs = LAY_OFS_0;
> @@ -1752,6 +1767,7 @@ static int ltdc_get_caps(struct drm_device *ddev)
>   		ldev->caps.ycbcr_output = false;
>   		ldev->caps.plane_reg_shadow = false;
>   		ldev->caps.crc = false;
> +		ldev->caps.dynamic_zorder = false;
>   		break;
>   	case HWVER_40100:
>   		ldev->caps.layer_ofs = LAY_OFS_1;
> @@ -1767,6 +1783,7 @@ static int ltdc_get_caps(struct drm_device *ddev)
>   		ldev->caps.ycbcr_output = true;
>   		ldev->caps.plane_reg_shadow = true;
>   		ldev->caps.crc = true;
> +		ldev->caps.dynamic_zorder = true;
>   		break;
>   	default:
>   		return -ENODEV;
> diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
> index 59fc5d1bbbab..4855898bd4c0 100644
> --- a/drivers/gpu/drm/stm/ltdc.h
> +++ b/drivers/gpu/drm/stm/ltdc.h
> @@ -28,6 +28,7 @@ struct ltdc_caps {
>   	bool ycbcr_output;	/* ycbcr output converter supported */
>   	bool plane_reg_shadow;	/* plane shadow registers ability */
>   	bool crc;		/* cyclic redundancy check supported */
> +	bool dynamic_zorder;	/* dynamic z-order */
>   };
>   
>   #define LTDC_MAX_LAYER	4
Dear Yannick,
Many thanks for your patch,
Applied on drm-misc-next.
Have a good day
Philippe :-)