examples: Add example out-of-tree module for RFNoC modules

This subdirectory is its own, self-contained project. It is supposed to
work against the UHD version it is shipped with.

Co-Authored-By: Martin Braun <martin.braun@ettus.com>
Co-Authored-By: Wade Fife <wade.fife@ni.com>

1 files changed, 77 insertions, 0 deletions

diff --git a/host/examples/rfnoc-example/apps/init_gain_block.cpp b/host/examples/rfnoc-example/apps/init_gain_block.cpp
new file mode 100644
index 000000000..f9de5f92c
--- /dev/null
+++ b/host/examples/rfnoc-example/apps/init_gain_block.cpp
@@ -0,0 +1,77 @@
+//
+// Copyright 2019 Ettus Research, a National Instruments Brand
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+// Example application to show how to write applications that depend on both UHD
+// and out-of-tree RFNoC modules.
+//
+// It will see if a USRP is runnging the gain block, if so, it will test to see
+// if it can change the gain.
+
+#include <uhd/exception.hpp>
+#include <uhd/rfnoc_graph.hpp>
+#include <uhd/utils/safe_main.hpp>
+#include <rfnoc/example/gain_block_control.hpp>
+#include <boost/program_options.hpp>
+
+namespace po = boost::program_options;
+
+int UHD_SAFE_MAIN(int argc, char* argv[])
+{
+    std::string args;
+
+    // setup the program options
+    po::options_description desc("Allowed options");
+    // clang-format off
+    desc.add_options()
+        ("help", "help message")
+        ("args", po::value<std::string>(&args)->default_value(""), "USRP device address args")
+    ;
+    // clang-format on
+    po::variables_map vm;
+    po::store(po::parse_command_line(argc, argv, desc), vm);
+    po::notify(vm);
+
+    // print the help message
+    if (vm.count("help")) {
+        std::cout << "Init RFNoC gain block " << desc << std::endl;
+        std::cout << std::endl
+                  << "This application attempts to find a gain block in a USRP "
+                     "and tries to peek/poke registers..\n"
+                  << std::endl;
+        return EXIT_SUCCESS;
+    }
+
+    // Create RFNoC graph object:
+    auto graph = uhd::rfnoc::rfnoc_graph::make(args);
+
+    // Verify we have a gain block:
+    auto gain_blocks = graph->find_blocks<rfnoc::example::gain_block_control>("");
+    if (gain_blocks.empty()) {
+        std::cout << "No gain block found." << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    auto gain_block =
+        graph->get_block<rfnoc::example::gain_block_control>(gain_blocks.front());
+    if (!gain_block) {
+        std::cout << "ERROR: Failed to extract block controller!" << std::endl;
+        return EXIT_FAILURE;
+    }
+    constexpr uint32_t new_gain_value = 42;
+    gain_block->set_gain_value(new_gain_value);
+    const uint32_t gain_value_read = gain_block->get_gain_value();
+
+    if (gain_value_read != new_gain_value) {
+        std::cout << "ERROR: Readback of gain value not working! "
+                  << "Expected: " << new_gain_value << " Read: " << gain_value_read
+                  << std::endl;
+        return EXIT_FAILURE;
+    } else {
+        std::cout << "Gain value read/write loopback successful!" << std::endl;
+    }
+
+    return EXIT_SUCCESS;
+}