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

[Yannick Fertre <yannick.fertre@foss.st.com>]

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
-- 
2.25.1