[PATCH RFC v4 2/7] drm: Introduce pixel_source DRM plane property

Jessica Zhang
2023-06-30T00:26:43Z

Add support for pixel_source property to drm_plane and related
documentation.

This enum property will allow user to specify a pixel source for the
plane. Possible pixel sources will be defined in the
drm_plane_pixel_source enum.

The current possible pixel sources are DRM_PLANE_PIXEL_SOURCE_FB and
DRM_PLANE_PIXEL_SOURCE_COLOR. The default value is *_SOURCE_FB.

Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
---
drivers/gpu/drm/drm_atomic_state_helper.c | 1 +
drivers/gpu/drm/drm_atomic_uapi.c | 4 ++
drivers/gpu/drm/drm_blend.c | 81 +++++++++++++++++++++++++++++++
include/drm/drm_blend.h | 2 +
include/drm/drm_plane.h | 21 ++++++++
5 files changed, 109 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
index fe14be2bd2b2..86fb876efbe6 100644
--- a/drivers/gpu/drm/drm_atomic_state_helper.c
+++ b/drivers/gpu/drm/drm_atomic_state_helper.c
@@ -252,6 +252,7 @@ void __drm_atomic_helper_plane_state_reset(struct drm_plane_state *plane_state,

plane_state->alpha = DRM_BLEND_ALPHA_OPAQUE;
plane_state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI;
+ plane_state->pixel_source = DRM_PLANE_PIXEL_SOURCE_FB;

if (plane_state->solid_fill_blob) {
drm_property_blob_put(plane_state->solid_fill_blob);
diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index a28b4ee79444..6e59c21af66b 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -596,6 +596,8 @@ static int drm_atomic_plane_set_property(struct drm_plane *plane,
drm_property_blob_put(solid_fill);

return ret;
+ } else if (property == plane->pixel_source_property) {
+ state->pixel_source = val;
} else if (property == plane->alpha_property) {
state->alpha = val;
} else if (property == plane->blend_mode_property) {
@@ -671,6 +673,8 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
} else if (property == plane->solid_fill_property) {
*val = state->solid_fill_blob ?
state->solid_fill_blob->base.id : 0;
+ } else if (property == plane->pixel_source_property) {
+ *val = state->pixel_source;
} else if (property == plane->alpha_property) {
*val = state->alpha;
} else if (property == plane->blend_mode_property) {
diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
index 38c3c5d6453a..8c100a957ee2 100644
--- a/drivers/gpu/drm/drm_blend.c
+++ b/drivers/gpu/drm/drm_blend.c
@@ -189,6 +189,18 @@
* solid_fill is set up with drm_plane_create_solid_fill_property(). It
* contains pixel data that drivers can use to fill a plane.
*
+ * pixel_source:
+ * pixel_source is set up with drm_plane_create_pixel_source_property().
+ * It is used to toggle the source of pixel data for the plane.
+ *
+ * Possible values:
+ *
+ * "FB":
+ * Framebuffer source
+ *
+ * "COLOR":
+ * solid_fill source
+ *
* Note that all the property extensions described here apply either to the
* plane or the CRTC (e.g. for the background color, which currently is not
* exposed and assumed to be black).
@@ -648,3 +660,72 @@ int drm_plane_create_solid_fill_property(struct drm_plane *plane)
return 0;
}
EXPORT_SYMBOL(drm_plane_create_solid_fill_property);
+
+/**
+ * drm_plane_create_pixel_source_property - create a new pixel source property
+ * @plane: drm plane
+ * @supported_sources: bitmask of supported pixel_sources for the driver (NOT
+ * including DRM_PLANE_PIXEL_SOURCE_FB, as it will be supported
+ * by default).
+ *
+ * This creates a new property describing the current source of pixel data for the
+ * plane.
+ *
+ * The property is exposed to userspace as an enumeration property called
+ * "pixel_source" and has the following enumeration values:
+ *
+ * "FB":
+ * Framebuffer pixel source
+ *
+ * "COLOR":
+ * Solid fill color pixel source
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_plane_create_pixel_source_property(struct drm_plane *plane,
+ unsigned int supported_sources)
+{
+ struct drm_device *dev = plane->dev;
+ struct drm_property *prop;
+ const struct drm_prop_enum_list enum_list[] = {
+ { DRM_PLANE_PIXEL_SOURCE_FB, "FB" },
+ { DRM_PLANE_PIXEL_SOURCE_COLOR, "COLOR" },
+ };
+ unsigned int valid_source_mask = BIT(DRM_PLANE_PIXEL_SOURCE_FB) |
+ BIT(DRM_PLANE_PIXEL_SOURCE_COLOR);
+ int i;
+
+ /* FB is supported by default */
+ supported_sources |= BIT(DRM_PLANE_PIXEL_SOURCE_FB);
+
+ if (WARN_ON(supported_sources & ~valid_source_mask))
+ return -EINVAL;
+
+ prop = drm_property_create(dev, DRM_MODE_PROP_ENUM, "pixel_source",
+ hweight32(supported_sources));
+
+ if (!prop)
+ return -ENOMEM;
+
+ for (i = 0; i < ARRAY_SIZE(enum_list); i++) {
+ int ret;
+
+ if (!(BIT(enum_list[i].type) & supported_sources))
+ continue;
+
+ ret = drm_property_add_enum(prop, enum_list[i].type, enum_list[i].name);
+
+ if (ret) {
+ drm_property_destroy(dev, prop);
+
+ return ret;
+ }
+ }
+
+ drm_object_attach_property(&plane->base, prop, DRM_PLANE_PIXEL_SOURCE_FB);
+ plane->pixel_source_property = prop;
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_plane_create_pixel_source_property);
diff --git a/include/drm/drm_blend.h b/include/drm/drm_blend.h
index 0338a860b9c8..31af7cfa5b1b 100644
--- a/include/drm/drm_blend.h
+++ b/include/drm/drm_blend.h
@@ -59,4 +59,6 @@ int drm_atomic_normalize_zpos(struct drm_device *dev,
int drm_plane_create_blend_mode_property(struct drm_plane *plane,
unsigned int supported_modes);
int drm_plane_create_solid_fill_property(struct drm_plane *plane);
+int drm_plane_create_pixel_source_property(struct drm_plane *plane,
+ unsigned int supported_sources);
#endif
diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
index f6ab313cb83e..73fb6cf8a5d9 100644
--- a/include/drm/drm_plane.h
+++ b/include/drm/drm_plane.h
@@ -59,6 +59,12 @@ struct drm_solid_fill {
uint32_t b;
};

+enum drm_plane_pixel_source {
+ DRM_PLANE_PIXEL_SOURCE_FB,
+ DRM_PLANE_PIXEL_SOURCE_COLOR,
+ DRM_PLANE_PIXEL_SOURCE_MAX
+};
+
/**
* struct drm_plane_state - mutable plane state
*
@@ -152,6 +158,14 @@ struct drm_plane_state {
*/
struct drm_solid_fill solid_fill;

+ /*
+ * @pixel_source:
+ *
+ * Source of pixel information for the plane. See
+ * drm_plane_create_pixel_source_property() for more details.
+ */
+ enum drm_plane_pixel_source pixel_source;
+
/**
* @alpha:
* Opacity of the plane with 0 as completely transparent and 0xffff as
@@ -742,6 +756,13 @@ struct drm_plane {
*/
struct drm_property *solid_fill_property;

+ /*
+ * @pixel_source_property:
+ * Optional pixel_source property for this plane. See
+ * drm_plane_create_pixel_source_property().
+ */
+ struct drm_property *pixel_source_property;
+
/**
* @alpha_property:
* Optional alpha property for this plane. See

--
2.41.0