drm/amd/display: add multiplier colorop

This adds support for a multiplier. This multiplier is
programmed via the HDR Multiplier in DCN.

With this change the following IGT tests pass:
kms_colorop --run plane-XR30-XR30-multiply_125
kms_colorop --run plane-XR30-XR30-multiply_inv_125

The color pipeline now consists of the following colorops:
1. 1D curve colorop
2. 3x4 CTM
3. Multiplier
4. 1D curve colorop
5. 1D LUT
6. 1D curve colorop
7. 1D LUT

Signed-off-by: Alex Hung <alex.hung@amd.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Simon Ser <contact@emersion.fr>
Link: https://patch.msgid.link/20251115000237.3561250-42-alex.hung@amd.com

Author: Alex Hung

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c

@@ -1419,6 +1419,35 @@ __set_dm_plane_colorop_3x4_matrix(struct drm_plane_state *plane_state,
 	return 0;
 }
 
+static int
+__set_dm_plane_colorop_multiplier(struct drm_plane_state *plane_state,
+				  struct dc_plane_state *dc_plane_state,
+				  struct drm_colorop *colorop)
+{
+	struct drm_colorop *old_colorop;
+	struct drm_colorop_state *colorop_state = NULL, *new_colorop_state;
+	struct drm_atomic_state *state = plane_state->state;
+	const struct drm_device *dev = colorop->dev;
+	int i = 0;
+
+	/* Multiplier */
+	old_colorop = colorop;
+	for_each_new_colorop_in_state(state, colorop, new_colorop_state, i) {
+		if (new_colorop_state->colorop == old_colorop &&
+		    new_colorop_state->colorop->type == DRM_COLOROP_MULTIPLIER) {
+			colorop_state = new_colorop_state;
+			break;
+		}
+	}
+
+	if (colorop_state && !colorop_state->bypass && colorop->type == DRM_COLOROP_MULTIPLIER) {
+		drm_dbg(dev, "Multiplier colorop with ID: %d\n", colorop->base.id);
+		dc_plane_state->hdr_mult = amdgpu_dm_fixpt_from_s3132(colorop_state->multiplier);
+	}
+
+	return 0;
+}
+
 static int
 __set_dm_plane_colorop_shaper(struct drm_plane_state *plane_state,
 			      struct dc_plane_state *dc_plane_state,
@@ -1633,6 +1662,17 @@ amdgpu_dm_plane_set_colorop_properties(struct drm_plane_state *plane_state,
 	if (ret)
 		return ret;
 
+	/* Multiplier */
+	colorop = colorop->next;
+	if (!colorop) {
+		drm_dbg(dev, "no multiplier colorop found\n");
+		return -EINVAL;
+	}
+
+	ret = __set_dm_plane_colorop_multiplier(plane_state, dc_plane_state, colorop);
+	if (ret)
+		return ret;
+
 	/* 1D Curve & LUT - SHAPER TF & LUT */
 	colorop = colorop->next;
 	if (!colorop) {

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_colorop.c

@@ -89,6 +89,21 @@ int amdgpu_dm_initialize_default_pipeline(struct drm_plane *plane, struct drm_pr
 
 	i++;
 
+	/* Multiplier */
+	ops[i] = kzalloc(sizeof(struct drm_colorop), GFP_KERNEL);
+	if (!ops[i]) {
+		ret = -ENOMEM;
+		goto cleanup;
+	}
+
+	ret = drm_plane_colorop_mult_init(dev, ops[i], plane);
+	if (ret)
+		goto cleanup;
+
+	drm_colorop_set_next_property(ops[i-1], ops[i]);
+
+	i++;
+
 	/* 1D curve - SHAPER TF */
 	ops[i] = kzalloc(sizeof(*ops[0]), GFP_KERNEL);
 	if (!ops[i]) {