drm/colorop: Add 3D LUT support to color pipeline

It is to be used to enable HDR by allowing userpace to create and pass
3D LUTs to kernel and hardware.

new drm_colorop_type: DRM_COLOROP_3D_LUT.

Reviewed-by: Simon Ser <[e-mail]>
Signed-off-by: Alex Hung <[e-mail]>
Reviewed-by: Daniel Stone <[e-mail]>
Reviewed-by: Melissa Wen <[e-mail]>
Reviewed-by: Sebastian Wick <[e-mail]>
Signed-off-by: Simon Ser <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

drivers/gpu/drm/drm_atomic.c

···
 	case DRM_COLOROP_MULTIPLIER:
 		drm_printf(p, "\tmultiplier=%llu\n", state->multiplier);
 		break;
+	case DRM_COLOROP_3D_LUT:
+		drm_printf(p, "\tsize=%d\n", colorop->size);
+		drm_printf(p, "\tinterpolation=%s\n",
+			   drm_get_colorop_lut3d_interpolation_name(colorop->lut3d_interpolation));
+		drm_printf(p, "\tdata blob id=%d\n", state->data ? state->data->base.id : 0);
+		break;
 	default:
 		break;
 	}

drivers/gpu/drm/drm_atomic_uapi.c

···
 	case DRM_COLOROP_CTM_3X4:
 		size = sizeof(struct drm_color_ctm_3x4);
 		break;
+	case DRM_COLOROP_3D_LUT:
+		size = colorop->size * colorop->size * colorop->size *
+		       sizeof(struct drm_color_lut32);
+		break;
 	default:
 		/* should never get here */
 		return -EINVAL;
···
 		state->curve_1d_type = val;
 	} else if (property == colorop->multiplier_property) {
 		state->multiplier = val;
+	} else if (property == colorop->lut3d_interpolation_property) {
+		colorop->lut3d_interpolation = val;
 	} else if (property == colorop->data_property) {
 		return drm_atomic_color_set_data_property(colorop, state,
 							  property, val);
···
 		*val = state->multiplier;
 	else if (property == colorop->size_property)
 		*val = colorop->size;
+	else if (property == colorop->lut3d_interpolation_property)
+		*val = colorop->lut3d_interpolation;
 	else if (property == colorop->data_property)
 		*val = (state->data) ? state->data->base.id : 0;
 	else

drivers/gpu/drm/drm_colorop.c

···
 	{ DRM_COLOROP_1D_LUT, "1D LUT" },
 	{ DRM_COLOROP_CTM_3X4, "3x4 Matrix"},
 	{ DRM_COLOROP_MULTIPLIER, "Multiplier"},
+	{ DRM_COLOROP_3D_LUT, "3D LUT"},
 };
 
 static const char * const colorop_curve_1d_type_names[] = {
···
 
 static const struct drm_prop_enum_list drm_colorop_lut1d_interpolation_list[] = {
 	{ DRM_COLOROP_LUT1D_INTERPOLATION_LINEAR, "Linear" },
+};
+
+
+static const struct drm_prop_enum_list drm_colorop_lut3d_interpolation_list[] = {
+	{ DRM_COLOROP_LUT3D_INTERPOLATION_TETRAHEDRAL, "Tetrahedral" },
 };
 
 /* Init Helpers */
···
 }
 EXPORT_SYMBOL(drm_plane_colorop_mult_init);
 
+int drm_plane_colorop_3dlut_init(struct drm_device *dev, struct drm_colorop *colorop,
+				 struct drm_plane *plane,
+				 uint32_t lut_size,
+				 enum drm_colorop_lut3d_interpolation_type interpolation,
+				 uint32_t flags)
+{
+	struct drm_property *prop;
+	int ret;
+
+	ret = drm_plane_colorop_init(dev, colorop, plane, DRM_COLOROP_3D_LUT, flags);
+	if (ret)
+		return ret;
+
+	/* LUT size */
+	prop = drm_property_create_range(dev, DRM_MODE_PROP_IMMUTABLE  | DRM_MODE_PROP_ATOMIC,
+					 "SIZE", 0, UINT_MAX);
+	if (!prop)
+		return -ENOMEM;
+
+	colorop->size_property = prop;
+	drm_object_attach_property(&colorop->base, colorop->size_property, lut_size);
+	colorop->size = lut_size;
+
+	/* interpolation */
+	prop = drm_property_create_enum(dev, 0, "LUT3D_INTERPOLATION",
+					drm_colorop_lut3d_interpolation_list,
+					ARRAY_SIZE(drm_colorop_lut3d_interpolation_list));
+	if (!prop)
+		return -ENOMEM;
+
+	colorop->lut3d_interpolation_property = prop;
+	drm_object_attach_property(&colorop->base, prop, interpolation);
+	colorop->lut3d_interpolation = interpolation;
+
+	/* data */
+	ret = drm_colorop_create_data_prop(dev, colorop);
+	if (ret)
+		return ret;
+
+	drm_colorop_reset(colorop);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_plane_colorop_3dlut_init);
+
 static void __drm_atomic_helper_colorop_duplicate_state(struct drm_colorop *colorop,
 							struct drm_colorop_state *state)
 {
···
 	[DRM_COLOROP_1D_LUT] = "1D LUT",
 	[DRM_COLOROP_CTM_3X4] = "3x4 Matrix",
 	[DRM_COLOROP_MULTIPLIER] = "Multiplier",
+	[DRM_COLOROP_3D_LUT] = "3D LUT",
 };
+
+static const char * const colorop_lu3d_interpolation_name[] = {
+	[DRM_COLOROP_LUT3D_INTERPOLATION_TETRAHEDRAL] = "Tetrahedral",
+};
+
 static const char * const colorop_lut1d_interpolation_name[] = {
 	[DRM_COLOROP_LUT1D_INTERPOLATION_LINEAR] = "Linear",
 };
···
 		return "unknown";
 
 	return colorop_lut1d_interpolation_name[type];
+}
+
+/**
+ * drm_get_colorop_lut3d_interpolation_name - return a string for interpolation type
+ * @type: interpolation type to compute name of
+ *
+ * In contrast to the other drm_get_*_name functions this one here returns a
+ * const pointer and hence is threadsafe.
+ */
+const char *drm_get_colorop_lut3d_interpolation_name(enum drm_colorop_lut3d_interpolation_type type)
+{
+	if (WARN_ON(type >= ARRAY_SIZE(colorop_lu3d_interpolation_name)))
+		return "unknown";
+
+	return colorop_lu3d_interpolation_name[type];
 }
 
 /**

include/drm/drm_colorop.h

···
 	enum drm_colorop_lut1d_interpolation_type lut1d_interpolation;
 
 	/**
+	 * @lut3d_interpolation:
+	 *
+	 * Read-only
+	 * Interpolation for DRM_COLOROP_3D_LUT
+	 */
+	enum drm_colorop_lut3d_interpolation_type lut3d_interpolation;
+
+	/**
 	 * @lut1d_interpolation_property:
 	 *
 	 * Read-only property for DRM_COLOROP_1D_LUT interpolation
···
 	 * Size property for custom LUT from userspace.
 	 */
 	struct drm_property *size_property;
+
+	/**
+	 * @lut3d_interpolation_property:
+	 *
+	 * Read-only property for DRM_COLOROP_3D_LUT interpolation
+	 */
+	struct drm_property *lut3d_interpolation_property;
 
 	/**
 	 * @data_property:
···
 				   struct drm_plane *plane, uint32_t flags);
 int drm_plane_colorop_mult_init(struct drm_device *dev, struct drm_colorop *colorop,
 				struct drm_plane *plane, uint32_t flags);
+int drm_plane_colorop_3dlut_init(struct drm_device *dev, struct drm_colorop *colorop,
+				 struct drm_plane *plane,
+				 uint32_t lut_size,
+				 enum drm_colorop_lut3d_interpolation_type interpolation,
+				 uint32_t flags);
 
 struct drm_colorop_state *
 drm_atomic_helper_colorop_duplicate_state(struct drm_colorop *colorop);
···
 
 const char *
 drm_get_colorop_lut1d_interpolation_name(enum drm_colorop_lut1d_interpolation_type type);
+
+const char *
+drm_get_colorop_lut3d_interpolation_name(enum drm_colorop_lut3d_interpolation_type type);
 
 void drm_colorop_set_next_property(struct drm_colorop *colorop, struct drm_colorop *next);
 

include/uapi/drm/drm_mode.h

···
 	 * property.
 	 */
 	DRM_COLOROP_MULTIPLIER,
+
+	/**
+	 * @DRM_COLOROP_3D_LUT:
+	 *
+	 * enum string "3D LUT"
+	 *
+	 * A 3D LUT of &drm_color_lut32 entries,
+	 * packed into a blob via the DATA property. The driver's expected
+	 * LUT size is advertised via the SIZE property, i.e., a 3D LUT with
+	 * 17x17x17 entries will have SIZE set to 17.
+	 *
+	 * The DATA blob is a 3D array of struct drm_color_lut32 with dimension
+	 * length of "size".
+	 * The LUT elements are traversed like so:
+	 *
+	 *   for B in range 0..n
+	 *     for G in range 0..n
+	 *       for R in range 0..n
+	 *        index = R + n * (G + n * B)
+	 *         color = lut3d[index]
+	 */
+	DRM_COLOROP_3D_LUT,
+};
+
+/**
+ * enum drm_colorop_lut3d_interpolation_type - type of 3DLUT interpolation
+ */
+enum drm_colorop_lut3d_interpolation_type {
+	/**
+	 * @DRM_COLOROP_LUT3D_INTERPOLATION_TETRAHEDRAL:
+	 *
+	 * Tetrahedral 3DLUT interpolation
+	 */
+	DRM_COLOROP_LUT3D_INTERPOLATION_TETRAHEDRAL,
 };
 
 /**