drm/amd/display: Implement custom degamma lut on dcn

[Why]
Custom degamma lut functions are a feature we would
like to support on compatible hardware

[How]
In atomic check, convert from array of drm_color_lut to
dc_transfer_func.  On hardware commit, allow for possibility
of custom degamma.  Both are based on the equivalent
regamma pipeline.

Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 32 insertions, 10 deletions

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
index b329393307e5..326f6fb7e0bc 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
@@ -231,18 +231,21 @@ void amdgpu_dm_set_ctm(struct dm_crtc_state *crtc)
  * preparation for hardware commit. If no lut is specified by user, we default
  * to SRGB degamma.
  *
- * Currently, we only support degamma bypass, or preprogrammed SRGB degamma.
- * Programmable degamma is not supported, and an attempt to do so will return
- * -EINVAL.
+ * We support degamma bypass, predefined SRGB, and custom degamma
  *
  * RETURNS:
- * 0 on success, -EINVAL if custom degamma curve is given.
+ * 0 on success
+ * -EINVAL if crtc_state has a degamma_lut of invalid size
+ * -ENOMEM if gamma allocation fails
  */
 int amdgpu_dm_set_degamma_lut(struct drm_crtc_state *crtc_state,
 			      struct dc_plane_state *dc_plane_state)
 {
 	struct drm_property_blob *blob = crtc_state->degamma_lut;
 	struct drm_color_lut *lut;
+	uint32_t lut_size;
+	struct dc_gamma *gamma;
+	bool ret;
 
 	if (!blob) {
 		/* Default to SRGB */
@@ -258,11 +261,30 @@ int amdgpu_dm_set_degamma_lut(struct drm_crtc_state *crtc_state,
 		return 0;
 	}
 
-	/* Otherwise, assume SRGB, since programmable degamma is not
-	 * supported.
-	 */
-	dc_plane_state->in_transfer_func->type = TF_TYPE_PREDEFINED;
-	dc_plane_state->in_transfer_func->tf = TRANSFER_FUNCTION_SRGB;
-	return -EINVAL;
+	gamma = dc_create_gamma();
+	if (!gamma)
+		return -ENOMEM;
+
+	lut_size = blob->length / sizeof(struct drm_color_lut);
+	gamma->num_entries = lut_size;
+	if (gamma->num_entries == MAX_COLOR_LUT_ENTRIES)
+		gamma->type = GAMMA_CUSTOM;
+	else {
+		dc_gamma_release(&gamma);
+		return -EINVAL;
+	}
+
+	__drm_lut_to_dc_gamma(lut, gamma, false);
+
+	dc_plane_state->in_transfer_func->type = TF_TYPE_DISTRIBUTED_POINTS;
+	ret = mod_color_calculate_degamma_params(dc_plane_state->in_transfer_func, gamma, true);
+	dc_gamma_release(&gamma);
+	if (!ret) {
+		dc_plane_state->in_transfer_func->type = TF_TYPE_BYPASS;
+		DRM_ERROR("Out of memory when calculating degamma params\n");
+		return -ENOMEM;
+	}
+
+	return 0;
 }