drm/amd/display: add plane degamma TF driver-specific property

Allow userspace to tell the kernel driver the input space and,
therefore, uses correct predefined transfer function (TF) to go from
encoded values to linear values.

v2:
- rename TF enum prefix from DRM_ to AMDGPU_ (Harry)
- remove HLG TF
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Joshua Ashton <joshua@froggi.es>
Co-developed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h

@@ -355,6 +355,11 @@ struct amdgpu_mode_info {
 	 * size of degamma LUT as supported by the driver (read-only).
 	 */
 	struct drm_property *plane_degamma_lut_size_property;
+	/**
+	 * @plane_degamma_tf_property: Plane pre-defined transfer function to
+	 * to go from scanout/encoded values to linear values.
+	 */
+	struct drm_property *plane_degamma_tf_property;
 };
 
 #define AMDGPU_MAX_BL_LEVEL 0xFF

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h

@@ -724,6 +724,18 @@ struct amdgpu_dm_wb_connector {
 
 extern const struct amdgpu_ip_block_version dm_ip_block;
 
+enum amdgpu_transfer_function {
+	AMDGPU_TRANSFER_FUNCTION_DEFAULT,
+	AMDGPU_TRANSFER_FUNCTION_SRGB,
+	AMDGPU_TRANSFER_FUNCTION_BT709,
+	AMDGPU_TRANSFER_FUNCTION_PQ,
+	AMDGPU_TRANSFER_FUNCTION_LINEAR,
+	AMDGPU_TRANSFER_FUNCTION_UNITY,
+	AMDGPU_TRANSFER_FUNCTION_GAMMA22,
+	AMDGPU_TRANSFER_FUNCTION_GAMMA24,
+	AMDGPU_TRANSFER_FUNCTION_GAMMA26,
+};
+
 struct dm_plane_state {
 	struct drm_plane_state base;
 	struct dc_plane_state *dc_state;
@@ -737,6 +749,13 @@ struct dm_plane_state {
 	 * The blob (if not NULL) is an array of &struct drm_color_lut.
 	 */
 	struct drm_property_blob *degamma_lut;
+	/**
+	 * @degamma_tf:
+	 *
+	 * Predefined transfer function to tell DC driver the input space to
+	 * linearize.
+	 */
+	enum amdgpu_transfer_function degamma_tf;
 };
 
 struct dm_crtc_state {

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

@@ -85,6 +85,18 @@ void amdgpu_dm_init_color_mod(void)
 }
 
 #ifdef AMD_PRIVATE_COLOR
+static const struct drm_prop_enum_list amdgpu_transfer_function_enum_list[] = {
+	{ AMDGPU_TRANSFER_FUNCTION_DEFAULT, "Default" },
+	{ AMDGPU_TRANSFER_FUNCTION_SRGB, "sRGB" },
+	{ AMDGPU_TRANSFER_FUNCTION_BT709, "BT.709" },
+	{ AMDGPU_TRANSFER_FUNCTION_PQ, "PQ (Perceptual Quantizer)" },
+	{ AMDGPU_TRANSFER_FUNCTION_LINEAR, "Linear" },
+	{ AMDGPU_TRANSFER_FUNCTION_UNITY, "Unity" },
+	{ AMDGPU_TRANSFER_FUNCTION_GAMMA22, "Gamma 2.2" },
+	{ AMDGPU_TRANSFER_FUNCTION_GAMMA24, "Gamma 2.4" },
+	{ AMDGPU_TRANSFER_FUNCTION_GAMMA26, "Gamma 2.6" },
+};
+
 int
 amdgpu_dm_create_color_properties(struct amdgpu_device *adev)
 {
@@ -105,6 +117,15 @@ amdgpu_dm_create_color_properties(struct amdgpu_device *adev)
 		return -ENOMEM;
 	adev->mode_info.plane_degamma_lut_size_property = prop;
 
+	prop = drm_property_create_enum(adev_to_drm(adev),
+					DRM_MODE_PROP_ENUM,
+					"AMD_PLANE_DEGAMMA_TF",
+					amdgpu_transfer_function_enum_list,
+					ARRAY_SIZE(amdgpu_transfer_function_enum_list));
+	if (!prop)
+		return -ENOMEM;
+	adev->mode_info.plane_degamma_tf_property = prop;
+
 	return 0;
 }
 #endif

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

@@ -1337,8 +1337,11 @@ static void amdgpu_dm_plane_drm_plane_reset(struct drm_plane *plane)
 	amdgpu_state = kzalloc(sizeof(*amdgpu_state), GFP_KERNEL);
 	WARN_ON(amdgpu_state == NULL);
 
-	if (amdgpu_state)
+	if (!amdgpu_state)
+		return;
+
 	__drm_atomic_helper_plane_reset(plane, &amdgpu_state->base);
+	amdgpu_state->degamma_tf = AMDGPU_TRANSFER_FUNCTION_DEFAULT;
 }
 
 static struct drm_plane_state *amdgpu_dm_plane_drm_plane_duplicate_state(struct drm_plane *plane)
@@ -1361,6 +1364,8 @@ static struct drm_plane_state *amdgpu_dm_plane_drm_plane_duplicate_state(struct
 		dm_plane_state->degamma_lut =
 			drm_property_blob_get(old_dm_plane_state->degamma_lut);
 
+	dm_plane_state->degamma_tf = old_dm_plane_state->degamma_tf;
+
 	return &dm_plane_state->base;
 }
 
@@ -1455,6 +1460,9 @@ dm_atomic_plane_attach_color_mgmt_properties(struct amdgpu_display_manager *dm,
 		drm_object_attach_property(&plane->base,
 					   mode_info.plane_degamma_lut_size_property,
 					   MAX_COLOR_LUT_ENTRIES);
+		drm_object_attach_property(&plane->base,
+					   dm->adev->mode_info.plane_degamma_tf_property,
+					   AMDGPU_TRANSFER_FUNCTION_DEFAULT);
 	}
 }
 
@@ -1477,6 +1485,11 @@ dm_atomic_plane_set_property(struct drm_plane *plane,
 							&replaced);
 		dm_plane_state->base.color_mgmt_changed |= replaced;
 		return ret;
+	} else if (property == adev->mode_info.plane_degamma_tf_property) {
+		if (dm_plane_state->degamma_tf != val) {
+			dm_plane_state->degamma_tf = val;
+			dm_plane_state->base.color_mgmt_changed = 1;
+		}
 	} else {
 		drm_dbg_atomic(plane->dev,
 			       "[PLANE:%d:%s] unknown property [PROP:%d:%s]]\n",
@@ -1500,6 +1513,8 @@ dm_atomic_plane_get_property(struct drm_plane *plane,
 	if (property == adev->mode_info.plane_degamma_lut_property) {
 		*val = (dm_plane_state->degamma_lut) ?
 			dm_plane_state->degamma_lut->base.id : 0;
+	} else if (property == adev->mode_info.plane_degamma_tf_property) {
+		*val = dm_plane_state->degamma_tf;
 	} else {
 		return -EINVAL;
 	}