Add support for pixel_source property to drm_plane and related
documentation. In addition, force pixel_source to
DRM_PLANE_PIXEL_SOURCE_FB in DRM_IOCTL_MODE_SETPLANE as to not break
legacy userspace.

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_NONE and
DRM_PLANE_PIXEL_SOURCE_FB with *_PIXEL_SOURCE_FB being the default value.

Signed-off-by: Jessica Zhang <quic_jessz...@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               | 85 +++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_plane.c               |  3 ++
 include/drm/drm_blend.h                   |  2 +
 include/drm/drm_plane.h                   | 21 ++++++++
 6 files changed, 116 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c 
b/drivers/gpu/drm/drm_atomic_state_helper.c
index 784e63d70a42..01638c51ce0a 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->color_encoding_property) {
                if (!drm_object_property_get_default_value(&plane->base,
diff --git a/drivers/gpu/drm/drm_atomic_uapi.c 
b/drivers/gpu/drm/drm_atomic_uapi.c
index d867e7f9f2cd..454f980e16c9 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -544,6 +544,8 @@ static int drm_atomic_plane_set_property(struct drm_plane 
*plane,
                state->src_w = val;
        } else if (property == config->prop_src_h) {
                state->src_h = val;
+       } 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) {
@@ -616,6 +618,8 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
                *val = state->src_w;
        } else if (property == config->prop_src_h) {
                *val = state->src_h;
+       } 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 6e74de833466..c500310a3d09 100644
--- a/drivers/gpu/drm/drm_blend.c
+++ b/drivers/gpu/drm/drm_blend.c
@@ -185,6 +185,21 @@
  *              plane does not expose the "alpha" property, then this is
  *              assumed to be 1.0
  *
+ * pixel_source:
+ *     pixel_source is set up with drm_plane_create_pixel_source_property().
+ *     It is used to toggle the active source of pixel data for the plane.
+ *     The plane will only display data from the set pixel_source -- any
+ *     data from other sources will be ignored.
+ *
+ *     Possible values:
+ *
+ *     "NONE":
+ *             No active pixel source.
+ *             Committing with a NONE pixel source will disable the plane.
+ *
+ *     "FB":
+ *             Framebuffer source set by the "FB_ID" property.
+ *
  * 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).
@@ -615,3 +630,73 @@ int drm_plane_create_blend_mode_property(struct drm_plane 
*plane,
        return 0;
 }
 EXPORT_SYMBOL(drm_plane_create_blend_mode_property);
+
+/**
+ * drm_plane_create_pixel_source_property - create a new pixel source property
+ * @plane: DRM plane
+ * @extra_sources: Bitmask of additional supported pixel_sources for the 
driver.
+ *                DRM_PLANE_PIXEL_SOURCE_FB always be enabled as a supported
+ *                source.
+ *
+ * This creates a new property describing the current source of pixel data for 
the
+ * plane. The pixel_source will be initialized as DRM_PLANE_PIXEL_SOURCE_FB by 
default.
+ *
+ * Drivers can set a custom default source by overriding the pixel_source 
value in
+ * drm_plane_funcs.reset()
+ *
+ * The property is exposed to userspace as an enumeration property called
+ * "pixel_source" and has the following enumeration values:
+ *
+ * "NONE":
+ *      No active pixel source
+ *
+ * "FB":
+ *     Framebuffer pixel source
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_plane_create_pixel_source_property(struct drm_plane *plane,
+                                          unsigned long extra_sources)
+{
+       struct drm_device *dev = plane->dev;
+       struct drm_property *prop;
+       static const struct drm_prop_enum_list enum_list[] = {
+               { DRM_PLANE_PIXEL_SOURCE_NONE, "NONE" },
+               { DRM_PLANE_PIXEL_SOURCE_FB, "FB" },
+       };
+       static const unsigned int valid_source_mask = 
BIT(DRM_PLANE_PIXEL_SOURCE_FB);
+       int i;
+
+       /* FB is supported by default */
+       unsigned long supported_sources = extra_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 | 
DRM_MODE_PROP_ATOMIC, "pixel_source",
+                       hweight32(supported_sources));
+
+       if (!prop)
+               return -ENOMEM;
+
+       for (i = 0; i < ARRAY_SIZE(enum_list); i++) {
+               int ret;
+
+               if (!test_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/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index 24e7998d1731..f342cf15412b 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -987,6 +987,9 @@ int drm_mode_setplane(struct drm_device *dev, void *data,
                return -ENOENT;
        }
 
+       if (plane->state && plane->state->pixel_source != 
DRM_PLANE_PIXEL_SOURCE_FB)
+               plane->state->pixel_source = DRM_PLANE_PIXEL_SOURCE_FB;
+
        if (plane_req->fb_id) {
                fb = drm_framebuffer_lookup(dev, file_priv, plane_req->fb_id);
                if (!fb) {
diff --git a/include/drm/drm_blend.h b/include/drm/drm_blend.h
index 88bdfec3bd88..122bbfbaae33 100644
--- a/include/drm/drm_blend.h
+++ b/include/drm/drm_blend.h
@@ -58,4 +58,6 @@ int drm_atomic_normalize_zpos(struct drm_device *dev,
                              struct drm_atomic_state *state);
 int drm_plane_create_blend_mode_property(struct drm_plane *plane,
                                         unsigned int supported_modes);
+int drm_plane_create_pixel_source_property(struct drm_plane *plane,
+                                          unsigned long extra_sources);
 #endif
diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
index 51291983ea44..89508b4dea4a 100644
--- a/include/drm/drm_plane.h
+++ b/include/drm/drm_plane.h
@@ -40,6 +40,12 @@ enum drm_scaling_filter {
        DRM_SCALING_FILTER_NEAREST_NEIGHBOR,
 };
 
+enum drm_plane_pixel_source {
+       DRM_PLANE_PIXEL_SOURCE_NONE,
+       DRM_PLANE_PIXEL_SOURCE_FB,
+       DRM_PLANE_PIXEL_SOURCE_MAX
+};
+
 /**
  * struct drm_plane_state - mutable plane state
  *
@@ -116,6 +122,14 @@ struct drm_plane_state {
        /** @src_h: height of visible portion of plane (in 16.16) */
        uint32_t src_h, src_w;
 
+       /**
+        * @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
@@ -699,6 +713,13 @@ struct drm_plane {
         */
        struct drm_plane_state *state;
 
+       /*
+        * @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

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