drm/amd/display: add get primary dpp pipe resource interface

[why]
Need to have a helper function to find the primary dp pipe of the plane
associated with a dpp pipe
Reviewed-by: Dillon Varone <dillon.varone@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_resource.c

@@ -1807,6 +1807,20 @@ struct pipe_ctx *resource_get_opp_head(const struct pipe_ctx *pipe_ctx)
 	return opp_head;
 }
 
+struct pipe_ctx *resource_get_primary_dpp_pipe(const struct pipe_ctx *dpp_pipe)
+{
+	struct pipe_ctx *pri_dpp_pipe = (struct pipe_ctx *) dpp_pipe;
+
+	ASSERT(resource_is_pipe_type(dpp_pipe, DPP_PIPE));
+	while (pri_dpp_pipe->prev_odm_pipe)
+		pri_dpp_pipe = pri_dpp_pipe->prev_odm_pipe;
+	while (pri_dpp_pipe->top_pipe &&
+			pri_dpp_pipe->top_pipe->plane_state == pri_dpp_pipe->plane_state)
+		pri_dpp_pipe = pri_dpp_pipe->top_pipe;
+	return pri_dpp_pipe;
+}
+
+
 int resource_get_mpc_slice_index(const struct pipe_ctx *pipe_ctx)
 {
 	struct pipe_ctx *split_pipe = pipe_ctx->top_pipe;

drivers/gpu/drm/amd/display/dc/inc/resource.h

@@ -409,6 +409,12 @@ struct pipe_ctx *resource_get_otg_master(const struct pipe_ctx *pipe_ctx);
  */
 struct pipe_ctx *resource_get_opp_head(const struct pipe_ctx *pipe_ctx);
 
+/*
+ * Get the DPP pipe allocated for MPC slice 0 and ODM slice 0 of the plane
+ * associated with dpp_pipe.
+ */
+struct pipe_ctx *resource_get_primary_dpp_pipe(const struct pipe_ctx *dpp_pipe);
+
 /*
  * Get the MPC slice index counting from 0 from left most slice
  * For example, if a DPP pipe is used as a secondary pipe in MPCC combine, MPC