Disable DMA on server exit

os/src/userspace/puzzlecmd.cpp

@@ -14,6 +14,7 @@
 #include <boost/asio.hpp>
 
 #include "puzzlefw.hpp"
+#include "logging.hpp"
 #include "interrupt_manager.hpp"
 #include "data_server.hpp"
 
@@ -115,6 +116,14 @@ void run_data_server(puzzlefw::PuzzleFwDevice& device)
 
     asio::io_context io;
 
+    // Catch Ctrl-C for controlled shut down.
+    asio::signal_set signals(io, SIGINT);
+    signals.async_wait(
+        [&io](auto& ec, int sig) {
+            log(LOG_INFO, "Got SIGINT, stopping server");
+            io.stop();
+        });
+
     // Reserve 3/4 of the DMA buffer for analog acquisition data.
     // Reserve 1/4 of the DMA buffer for timetagger data.
     size_t acq_buf_size = 3 * 4096 * (device.dma_buffer_size() / 4096 / 4);
@@ -145,14 +154,23 @@ void run_data_server(puzzlefw::PuzzleFwDevice& device)
         device,
         std::chrono::milliseconds(100));
 
+    // Disable DMA engine on exit from this function.
+    struct ScopeGuard {
+        PuzzleFwDevice& m_device;
+        ScopeGuard(PuzzleFwDevice& device) : m_device(device) { }
+        ~ScopeGuard() { m_device.set_dma_enabled(false); }
+    } scope_guard(device);
+
     // Clear DMA errors, then enable DMA engine.
     device.clear_dma_errors();
     device.set_dma_enabled(true);
 
     acq_server.start_server();
+    timetagger_server.start_server();
     acq_stream.set_enabled(true);
-// TODO -- timetagger
+    timetagger_stream.set_enabled(true);
 
+    log(LOG_INFO, "Running, press Ctrl-C to stop");
     io.run();
 }