rfnoc: graph_utils: Add ability to declare back-edges

rfnoc::connect_through_blocks(), unlike rfnoc_graph::connect(), did not
have an argument to declare a back-edge. This patch remedies this
situation by adding a skip_property_propagation argument that works
exactly as with rfnoc_graph::connect().

2 files changed, 13 insertions, 4 deletions

diff --git a/host/include/uhd/utils/graph_utils.hpp b/host/include/uhd/utils/graph_utils.hpp
index 6b264032c..29f488983 100644
--- a/host/include/uhd/utils/graph_utils.hpp
+++ b/host/include/uhd/utils/graph_utils.hpp
@@ -63,6 +63,10 @@ std::vector<graph_edge_t> UHD_API get_block_chain(const rfnoc_graph::sptr graph,
  *  \param src_port Block port where the path starts
  *  \param dst_blk Destination block's ID
  *  \param dst_port Block port where the path ends
+ *  \param skip_property_propagation Declare back-edge
+ *                                   (see also uhd::rfnoc::rfnoc_graph::connect())
+ *                                   If true, it will declare only the first
+ *                                   connection in this chain as a back-edge.
  *
  *  \return The edge list representing the data path requested
  */
@@ -70,6 +74,7 @@ std::vector<graph_edge_t> UHD_API connect_through_blocks(rfnoc_graph::sptr graph
     const block_id_t src_blk,
     const size_t src_port,
     const block_id_t dst_blk,
-    const size_t dst_port);
+    const size_t dst_port,
+    const bool skip_property_propagation = false);
 
 }} // namespace uhd::rfnoc
diff --git a/host/lib/utils/graph_utils.cpp b/host/lib/utils/graph_utils.cpp
index 89df30e15..aeb71b091 100644
--- a/host/lib/utils/graph_utils.cpp
+++ b/host/lib/utils/graph_utils.cpp
@@ -87,7 +87,8 @@ std::vector<graph_edge_t> connect_through_blocks(rfnoc_graph::sptr graph,
     const block_id_t src_blk,
     const size_t src_port,
     const block_id_t dst_blk,
-    const size_t dst_port)
+    const size_t dst_port,
+    const bool skip_property_propagation)
 {
     // First, create a chain from the source block to a stream endpoint
     auto block_chain = get_block_chain(graph, src_blk, src_port, true);
@@ -136,6 +137,7 @@ std::vector<graph_edge_t> connect_through_blocks(rfnoc_graph::sptr graph,
     std::string sep_to_dst_id;
     size_t sep_to_dst_port         = 0;
     bool has_sep_to_dst_connection = false;
+    bool skip_pp                   = skip_property_propagation;
 
     for (auto edge : block_chain) {
         if (uhd::rfnoc::block_id_t(edge.dst_blockid).match(uhd::rfnoc::NODE_ID_SEP)) {
@@ -149,11 +151,13 @@ std::vector<graph_edge_t> connect_through_blocks(rfnoc_graph::sptr graph,
             sep_to_dst_port           = edge.dst_port;
         } else {
             graph->connect(
-                edge.src_blockid, edge.src_port, edge.dst_blockid, edge.dst_port);
+                edge.src_blockid, edge.src_port, edge.dst_blockid, edge.dst_port, skip_pp);
+            skip_pp = false;
         }
     }
     if (has_src_to_sep_connection && has_sep_to_dst_connection) {
-        graph->connect(src_to_sep_id, src_to_sep_port, sep_to_dst_id, sep_to_dst_port);
+        graph->connect(
+            src_to_sep_id, src_to_sep_port, sep_to_dst_id, sep_to_dst_port, skip_pp);
     } else if (has_src_to_sep_connection != has_sep_to_dst_connection) {
         const std::string err_msg = "Incomplete path. Only one SEP edge found.";
         UHD_LOG_TRACE("GRAPH_UTILS", err_msg);