drm/colorop: Add 1D Curve Custom LUT type

We've previously introduced DRM_COLOROP_1D_CURVE for
pre-defined 1D curves. But we also have HW that supports
custom curves and userspace needs the ability to pass
custom curves, aka LUTs.

This patch introduces a new colorop type, called
DRM_COLOROP_1D_LUT that provides a SIZE property which
is used by a driver to advertise the supported SIZE
of the LUT, as well as a DATA property which userspace
uses to set the LUT.

DATA and size function in the same way as current drm_crtc
GAMMA and DEGAMMA LUTs.

Reviewed-by: Simon Ser <contact@emersion.fr>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Co-developed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Simon Ser <contact@emersion.fr>
Link: https://patch.msgid.link/20251115000237.3561250-38-alex.hung@amd.com

Author: Alex Hung

drivers/gpu/drm/drm_atomic.c

@@ -794,6 +794,10 @@ static void drm_atomic_colorop_print_state(struct drm_printer *p,
 		drm_printf(p, "\tcurve_1d_type=%s\n",
 			   drm_get_colorop_curve_1d_type_name(state->curve_1d_type));
 		break;
+	case DRM_COLOROP_1D_LUT:
+		drm_printf(p, "\tsize=%d\n", colorop->size);
+		drm_printf(p, "\tdata blob id=%d\n", state->data ? state->data->base.id : 0);
+		break;
 	case DRM_COLOROP_CTM_3X4:
 		drm_printf(p, "\tdata blob id=%d\n", state->data ? state->data->base.id : 0);
 		break;

drivers/gpu/drm/drm_atomic_uapi.c

@@ -699,6 +699,9 @@ static int drm_atomic_color_set_data_property(struct drm_colorop *colorop,
 	bool replaced = false;
 
 	switch (colorop->type) {
+	case DRM_COLOROP_1D_LUT:
+		size = colorop->size * sizeof(struct drm_color_lut32);
+		break;
 	case DRM_COLOROP_CTM_3X4:
 		size = sizeof(struct drm_color_ctm_3x4);
 		break;
@@ -750,6 +753,8 @@ drm_atomic_colorop_get_property(struct drm_colorop *colorop,
 		*val = state->bypass;
 	else if (property == colorop->curve_1d_type_property)
 		*val = state->curve_1d_type;
+	else if (property == colorop->size_property)
+		*val = colorop->size;
 	else if (property == colorop->data_property)
 		*val = (state->data) ? state->data->base.id : 0;
 	else

drivers/gpu/drm/drm_colorop.c

@@ -64,6 +64,7 @@
 
 static const struct drm_prop_enum_list drm_colorop_type_enum_list[] = {
 	{ DRM_COLOROP_1D_CURVE, "1D Curve" },
+	{ DRM_COLOROP_1D_LUT, "1D LUT" },
 	{ DRM_COLOROP_CTM_3X4, "3x4 Matrix"},
 };
 
@@ -264,6 +265,47 @@ static int drm_colorop_create_data_prop(struct drm_device *dev, struct drm_color
 	return 0;
 }
 
+/**
+ * drm_plane_colorop_curve_1d_lut_init - Initialize a DRM_COLOROP_1D_LUT
+ *
+ * @dev: DRM device
+ * @colorop: The drm_colorop object to initialize
+ * @plane: The associated drm_plane
+ * @lut_size: LUT size supported by driver
+ * @return zero on success, -E value on failure
+ */
+int drm_plane_colorop_curve_1d_lut_init(struct drm_device *dev, struct drm_colorop *colorop,
+					struct drm_plane *plane, uint32_t lut_size)
+{
+	struct drm_property *prop;
+	int ret;
+
+	ret = drm_plane_colorop_init(dev, colorop, plane, DRM_COLOROP_1D_LUT);
+	if (ret)
+		return ret;
+
+	/* initialize 1D LUT only attribute */
+	/* 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;
+
+	/* data */
+	ret = drm_colorop_create_data_prop(dev, colorop);
+	if (ret)
+		return ret;
+
+	drm_colorop_reset(colorop);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_plane_colorop_curve_1d_lut_init);
+
 int drm_plane_colorop_ctm_3x4_init(struct drm_device *dev, struct drm_colorop *colorop,
 				   struct drm_plane *plane)
 {
@@ -371,6 +413,7 @@ void drm_colorop_reset(struct drm_colorop *colorop)
 
 static const char * const colorop_type_name[] = {
 	[DRM_COLOROP_1D_CURVE] = "1D Curve",
+	[DRM_COLOROP_1D_LUT] = "1D LUT",
 	[DRM_COLOROP_CTM_3X4] = "3x4 Matrix",
 };
 

include/drm/drm_colorop.h

@@ -257,13 +257,27 @@ struct drm_colorop {
 	 */
 	struct drm_property *bypass_property;
 
+	/**
+	 * @size:
+	 *
+	 * Number of entries of the custom LUT. This should be read-only.
+	 */
+	uint32_t size;
+
 	/**
 	 * @curve_1d_type_property:
 	 *
 	 * Sub-type for DRM_COLOROP_1D_CURVE type.
 	 */
 	struct drm_property *curve_1d_type_property;
 
+	/**
+	 * @size_property:
+	 *
+	 * Size property for custom LUT from userspace.
+	 */
+	struct drm_property *size_property;
+
 	/**
 	 * @data_property:
 	 *
@@ -311,6 +325,8 @@ void drm_colorop_cleanup(struct drm_colorop *colorop);
 
 int drm_plane_colorop_curve_1d_init(struct drm_device *dev, struct drm_colorop *colorop,
 				    struct drm_plane *plane, u64 supported_tfs);
+int drm_plane_colorop_curve_1d_lut_init(struct drm_device *dev, struct drm_colorop *colorop,
+					struct drm_plane *plane, uint32_t lut_size);
 int drm_plane_colorop_ctm_3x4_init(struct drm_device *dev, struct drm_colorop *colorop,
 				   struct drm_plane *plane);
 

include/uapi/drm/drm_mode.h

@@ -902,6 +902,20 @@ enum drm_colorop_type {
 	 */
 	DRM_COLOROP_1D_CURVE,
 
+	/**
+	 * @DRM_COLOROP_1D_LUT:
+	 *
+	 * enum string "1D LUT"
+	 *
+	 * A simple 1D LUT of uniformly spaced &drm_color_lut32 entries,
+	 * packed into a blob via the DATA property. The driver's
+	 * expected LUT size is advertised via the SIZE property.
+	 *
+	 * The DATA blob is an array of struct drm_color_lut32 with size
+	 * of "size".
+	 */
+	DRM_COLOROP_1D_LUT,
+
 	/**
 	 * @DRM_COLOROP_CTM_3X4:
 	 *