mpmd: Device discovery fixes and cleanup

- Fixed issue where the "addr" device args was not honored
- Results returned by find only enumerate mgmt_addrs
- Explicitly require addr to be specified for RFNoC comms
- Cleaned up constants for mgmt_addr, addr and second_addr

Reviewed-by: Martin Braun <martin.braun@ettus.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/host/lib/usrp/mpmd/mpmd_xport_ctrl_udp.cpp b/host/lib/usrp/mpmd/mpmd_xport_ctrl_udp.cpp
index de4b3bbba..0da080724 100644
--- a/host/lib/usrp/mpmd/mpmd_xport_ctrl_udp.cpp
+++ b/host/lib/usrp/mpmd/mpmd_xport_ctrl_udp.cpp
@@ -26,9 +26,13 @@ namespace {
         const uhd::device_addr_t& mb_args
     ) {
         // mb_args must always include addr
-        std::vector<std::string> addrs{mb_args["addr"]};
-        if (mb_args.has_key("second_addr")){
-            addrs.push_back(mb_args["second_addr"]);
+        if (not mb_args.has_key(FIRST_ADDR_KEY)) {
+            throw uhd::runtime_error("The " + FIRST_ADDR_KEY + " key must be specified in "
+                "device args to create an Ethernet transport to an RFNoC block");
+        }
+        std::vector<std::string> addrs{mb_args[FIRST_ADDR_KEY]};
+        if (mb_args.has_key(SECOND_ADDR_KEY)){
+            addrs.push_back(mb_args[SECOND_ADDR_KEY]);
         }
         return addrs;
     }