drm: Introduce plane and CRTC scaling filter properties

Introduce per-plane and per-CRTC scaling filter properties to allow
userspace to select the driver's default scaling filter or
Nearest-neighbor(NN) filter for upscaling operations on CRTC and
plane.

Drivers can set up this property for a plane by calling
drm_plane_create_scaling_filter() and for a CRTC by calling
drm_crtc_create_scaling_filter().

NN filter works by filling in the missing color values in the upscaled
image with that of the coordinate-mapped nearest source pixel value.

NN filter for integer multiple scaling can be particularly useful for
for pixel art games that rely on sharp, blocky images to deliver their
distinctive look.

changes since: v6:
* Move property doc to existing "Standard CRTC Properties" and
  "Plane Composition Properties" doc comments (Simon)
changes since v3:
* Refactor code, add new function for common code (Ville)
changes since v2:
* Create per-plane and per-CRTC scaling filter property (Ville)
changes since v1:
* None
changes since RFC:
* Add separate properties for plane and CRTC (Ville)

Link: https://github.com/xbmc/xbmc/pull/18194
Link: https://github.com/xbmc/xbmc/pull/18567
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Acked-by: Simon Ser <contact@emersion.fr>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201020161427.6941-2-pankaj.laxminarayan.bharadiya@intel.com

drivers/gpu/drm/drm_atomic_uapi.c

@@ -469,6 +469,8 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 			return -EFAULT;
 
 		set_out_fence_for_crtc(state->state, crtc, fence_ptr);
+	} else if (property == crtc->scaling_filter_property) {
+		state->scaling_filter = val;
 	} else if (crtc->funcs->atomic_set_property) {
 		return crtc->funcs->atomic_set_property(crtc, state, property, val);
 	} else {
@@ -503,6 +505,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
 		*val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
 	else if (property == config->prop_out_fence_ptr)
 		*val = 0;
+	else if (property == crtc->scaling_filter_property)
+		*val = state->scaling_filter;
 	else if (crtc->funcs->atomic_get_property)
 		return crtc->funcs->atomic_get_property(crtc, state, property, val);
 	else
@@ -585,6 +589,8 @@ static int drm_atomic_plane_set_property(struct drm_plane *plane,
 					sizeof(struct drm_rect),
 					&replaced);
 		return ret;
+	} else if (property == plane->scaling_filter_property) {
+		state->scaling_filter = val;
 	} else if (plane->funcs->atomic_set_property) {
 		return plane->funcs->atomic_set_property(plane, state,
 				property, val);
@@ -643,6 +649,8 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
 	} else if (property == config->prop_fb_damage_clips) {
 		*val = (state->fb_damage_clips) ?
 			state->fb_damage_clips->base.id : 0;
+	} else if (property == plane->scaling_filter_property) {
+		*val = state->scaling_filter;
 	} else if (plane->funcs->atomic_get_property) {
 		return plane->funcs->atomic_get_property(plane, state, property, val);
 	} else {

drivers/gpu/drm/drm_blend.c

@@ -194,6 +194,19 @@
  * 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).
+ *
+ * SCALING_FILTER:
+ *
+ *     Indicates scaling filter to be used for plane scaler
+ *
+ *     The value of this property can be one of the following:
+ *     Default:
+ *             Driver's default scaling filter
+ *     Nearest Neighbor:
+ *             Nearest Neighbor scaling filter
+ *
+ * Drivers can set up this property for a plane by calling
+ * drm_plane_create_scaling_filter_property
  */
 
 /**

drivers/gpu/drm/drm_crtc.c

@@ -229,6 +229,15 @@ struct dma_fence *drm_crtc_create_fence(struct drm_crtc *crtc)
  * 	user-space must set this property to 0.
  *
  * 	Setting MODE_ID to 0 will release reserved resources for the CRTC.
+ * SCALING_FILTER:
+ *	Atomic property for setting the scaling filter for CRTC scaler
+ *
+ *	The value of this property can be one of the following:
+ *	Default:
+ *		Driver's default scaling filter
+ *	Nearest Neighbor:
+ *		Nearest Neighbor scaling filter
+ *
  */
 
 /**
@@ -774,3 +783,34 @@ int drm_mode_crtc_set_obj_prop(struct drm_mode_object *obj,
 
 	return ret;
 }
+
+/**
+ * drm_crtc_create_scaling_filter_property - create a new scaling filter
+ * property
+ *
+ * @crtc: drm CRTC
+ * @supported_filters: bitmask of supported scaling filters, must include
+ *		       BIT(DRM_SCALING_FILTER_DEFAULT).
+ *
+ * This function lets driver to enable the scaling filter property on a given
+ * CRTC.
+ *
+ * RETURNS:
+ * Zero for success or -errno
+ */
+int drm_crtc_create_scaling_filter_property(struct drm_crtc *crtc,
+					    unsigned int supported_filters)
+{
+	struct drm_property *prop =
+		drm_create_scaling_filter_prop(crtc->dev, supported_filters);
+
+	if (IS_ERR(prop))
+		return PTR_ERR(prop);
+
+	drm_object_attach_property(&crtc->base, prop,
+				   DRM_SCALING_FILTER_DEFAULT);
+	crtc->scaling_filter_property = prop;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_crtc_create_scaling_filter_property);

drivers/gpu/drm/drm_crtc_internal.h

@@ -72,6 +72,9 @@ int drm_crtc_force_disable(struct drm_crtc *crtc);
 
 struct dma_fence *drm_crtc_create_fence(struct drm_crtc *crtc);
 
+struct drm_property *
+drm_create_scaling_filter_prop(struct drm_device *dev,
+			       unsigned int supported_filters);
 /* IOCTLs */
 int drm_mode_getcrtc(struct drm_device *dev,
 		     void *data, struct drm_file *file_priv);

drivers/gpu/drm/drm_plane.c

@@ -1231,3 +1231,76 @@ out:
 
 	return ret;
 }
+
+struct drm_property *
+drm_create_scaling_filter_prop(struct drm_device *dev,
+			       unsigned int supported_filters)
+{
+	struct drm_property *prop;
+	static const struct drm_prop_enum_list props[] = {
+		{ DRM_SCALING_FILTER_DEFAULT, "Default" },
+		{ DRM_SCALING_FILTER_NEAREST_NEIGHBOR, "Nearest Neighbor" },
+	};
+	unsigned int valid_mode_mask = BIT(DRM_SCALING_FILTER_DEFAULT) |
+				       BIT(DRM_SCALING_FILTER_NEAREST_NEIGHBOR);
+	int i;
+
+	if (WARN_ON((supported_filters & ~valid_mode_mask) ||
+		    ((supported_filters & BIT(DRM_SCALING_FILTER_DEFAULT)) == 0)))
+		return ERR_PTR(-EINVAL);
+
+	prop = drm_property_create(dev, DRM_MODE_PROP_ENUM,
+				   "SCALING_FILTER",
+				   hweight32(supported_filters));
+	if (!prop)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < ARRAY_SIZE(props); i++) {
+		int ret;
+
+		if (!(BIT(props[i].type) & supported_filters))
+			continue;
+
+		ret = drm_property_add_enum(prop, props[i].type,
+					    props[i].name);
+
+		if (ret) {
+			drm_property_destroy(dev, prop);
+
+			return ERR_PTR(ret);
+		}
+	}
+
+	return prop;
+}
+
+/**
+ * drm_plane_create_scaling_filter_property - create a new scaling filter
+ * property
+ *
+ * @plane: drm plane
+ * @supported_filters: bitmask of supported scaling filters, must include
+ *		       BIT(DRM_SCALING_FILTER_DEFAULT).
+ *
+ * This function lets driver to enable the scaling filter property on a given
+ * plane.
+ *
+ * RETURNS:
+ * Zero for success or -errno
+ */
+int drm_plane_create_scaling_filter_property(struct drm_plane *plane,
+					     unsigned int supported_filters)
+{
+	struct drm_property *prop =
+		drm_create_scaling_filter_prop(plane->dev, supported_filters);
+
+	if (IS_ERR(prop))
+		return PTR_ERR(prop);
+
+	drm_object_attach_property(&plane->base, prop,
+				   DRM_SCALING_FILTER_DEFAULT);
+	plane->scaling_filter_property = prop;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_plane_create_scaling_filter_property);

include/drm/drm_crtc.h

@@ -324,6 +324,13 @@ struct drm_crtc_state {
 	 */
 	bool self_refresh_active;
 
+	/**
+	 * @scaling_filter:
+	 *
+	 * Scaling filter to be applied
+	 */
+	enum drm_scaling_filter scaling_filter;
+
 	/**
 	 * @event:
 	 *
@@ -1083,6 +1090,12 @@ struct drm_crtc {
 	/** @properties: property tracking for this CRTC */
 	struct drm_object_properties properties;
 
+	/**
+	 * @scaling_filter_property: property to apply a particular filter while
+	 * scaling.
+	 */
+	struct drm_property *scaling_filter_property;
+
 	/**
 	 * @state:
 	 *
@@ -1266,4 +1279,7 @@ static inline struct drm_crtc *drm_crtc_find(struct drm_device *dev,
 #define drm_for_each_crtc(crtc, dev) \
 	list_for_each_entry(crtc, &(dev)->mode_config.crtc_list, head)
 
+int drm_crtc_create_scaling_filter_property(struct drm_crtc *crtc,
+					    unsigned int supported_filters);
+
 #endif /* __DRM_CRTC_H__ */

include/drm/drm_plane.h

@@ -35,6 +35,11 @@ struct drm_crtc;
 struct drm_printer;
 struct drm_modeset_acquire_ctx;
 
+enum drm_scaling_filter {
+	DRM_SCALING_FILTER_DEFAULT,
+	DRM_SCALING_FILTER_NEAREST_NEIGHBOR,
+};
+
 /**
  * struct drm_plane_state - mutable plane state
  *
@@ -214,6 +219,13 @@ struct drm_plane_state {
 	 */
 	bool visible;
 
+	/**
+	 * @scaling_filter:
+	 *
+	 * Scaling filter to be applied
+	 */
+	enum drm_scaling_filter scaling_filter;
+
 	/**
 	 * @commit: Tracks the pending commit to prevent use-after-free conditions,
 	 * and for async plane updates.
@@ -724,6 +736,12 @@ struct drm_plane {
 	 * See drm_plane_create_color_properties().
 	 */
 	struct drm_property *color_range_property;
+
+	/**
+	 * @scaling_filter_property: property to apply a particular filter while
+	 * scaling.
+	 */
+	struct drm_property *scaling_filter_property;
 };
 
 #define obj_to_plane(x) container_of(x, struct drm_plane, base)
@@ -862,4 +880,7 @@ drm_plane_get_damage_clips(const struct drm_plane_state *state)
 					state->fb_damage_clips->data : NULL);
 }
 
+int drm_plane_create_scaling_filter_property(struct drm_plane *plane,
+					     unsigned int supported_filters);
+
 #endif