doc/user_manual.md

@@ -351,11 +351,9 @@ In the response string, such data elements are separated by space characters.
 | `AIN:TRIGGER:EXT:CHANNEL` | External trigger channel. |
 | `AIN:TRIGGER:EXT:EDGE`    | External trigger edge. |
 | `AIN:ACQUIRE:ENABLE`      | Enable analog acquisition. |
-| `AIN:CLEAR`               | Clear buffer and drop data connection. |
 | `TT:SAMPLE?`              | Digital input state. |
 | `TT:EVENT:MASK`           | Timetagger event mask. |
 | `TT:MARK`                 | Emit timetagger marker. |
-| `TT:CLEAR`                | Clear buffer and drop data connection. |
 | `TEMP:FPGA?`              | FPGA temperature. |
 | `IPCFG[:SAVED]`           | IP address configuration. |
 | `HALT`                    | Shut down system. |
@@ -628,17 +626,6 @@ When disabled, all triggers are ignored and any ongoing analog acquisition stops
 Query: `AIN:ACQUIRE:ENABLE?` <br>
 Response: either `0` or `1`.
 
-### `AIN:CLEAR`
-
-Command: `AIN:CLEAR`
-
-This command clears internal buffers holding analog acquisition data.
-It also drops the current data connection to port 5001, if any.
-
-Clients should send this command just before connecting to the analog
-sample data port and enabling analog data acquisition.
-This prevents the transmission of stale data from a previous run.
-
 ### `TT:SAMPLE?`
 
 Query: `TT:SAMPLE?` <br>
@@ -675,17 +662,6 @@ Command: `TT:MARK`
 
 This command emits a marker record in the timetagger event stream.
 
-### `TT:CLEAR`
-
-Command: `TT:CLEAR`
-
-This command clears internal buffers holding timetagger data.
-It also drops the current data connection to port 5002, if any.
-
-Clients should send this command just before connecting to the timetagger
-data port and enabling timetagger events.
-This prevents the transmission of stale data from a previous run.
-
 ### `TEMP:FPGA?`
 
 Query: `TEMP:FPGA?` <br>

sw/src/userspace/data_server.hpp

@@ -115,12 +115,6 @@ public:
         asio::ip::tcp::endpoint addr(asio::ip::address_v6::any(), m_tcp_port);
         m_acceptor.bind(addr);
 
-        // Clear buffer, then enable DMA stream.
-        if (! m_connection.is_open()) {
-            discard_stale_data();
-            m_dma_stream.set_enabled(true);
-        }
-
         // Start listening for connections.
         m_acceptor.listen();
 
@@ -139,6 +133,9 @@ public:
      */
     void stop_server()
     {
+        // Disable DMA stream and clear buffer.
+        m_dma_stream.init();
+
         // Stop accepting connections.
         if (m_acceptor.is_open()) {
             log(LOG_INFO, "Closing TCP server on port %d", m_tcp_port);
@@ -152,34 +149,6 @@ public:
             m_stale_receive = true;
             m_stale_send = m_send_in_progress;
         }
-
-        // Disable DMA stream and clear buffer.
-        m_dma_stream.init();
-    }
-
-    /**
-     * Disconnect the current client and discard all pending data.
-     *
-     * If a multi-threaded Asio event loop is running, this method may only
-     * be called through the strand returned by "get_executor()".
-     */
-    void clear_data()
-    {
-        // Close the current connection.
-        if (m_connection.is_open()) {
-            log(LOG_INFO, "Closing connection to port %d", m_tcp_port);
-            m_connection.close();
-            m_stale_receive = true;
-            m_stale_send = m_send_in_progress;
-        }
-
-        // Disable DMA stream and clear buffer.
-        discard_stale_data();
-
-        // Re-enable DMA stream.
-        if (m_acceptor.is_open()) {
-            m_dma_stream.set_enabled(true);
-        }
     }
 
     /**
@@ -303,6 +272,10 @@ private:
                 [this](auto ec, size_t n){ handle_receive(ec, n); });
         }
 
+        // Clear buffer, then enable DMA stream.
+        discard_stale_data();
+        m_dma_stream.set_enabled(true);
+
         // Prepare to send data.
         transmit_data(false);
     }

sw/src/userspace/puzzlefw.hpp

@@ -732,6 +732,7 @@ public:
         // Set up DMA buffer segment.
         m_device.write_reg(m_reg.addr_start, m_buf_start);
         m_device.write_reg(m_reg.addr_end, m_buf_end);
+        m_device.write_reg(m_reg.addr_limit, m_buf_end - POINTER_MARGIN);
 
         // Initialize DMA stream and reset write pointer.
         init();
@@ -790,9 +791,6 @@ public:
 
         // Reset read pointer.
         m_read_pointer = m_buf_start;
-
-        // Reset write limit pointer.
-        m_device.write_reg(m_reg.addr_limit, m_buf_end - POINTER_MARGIN);
     }
 
     /** Return the number of bytes available in the DMA buffer. */

sw/src/userspace/remotectl.cpp

@@ -481,8 +481,6 @@ public:
       , m_model_name(model_name)
       , m_serial_number(serial_number)
       , m_control_server(nullptr)
-      , m_acquisition_server(nullptr)
-      , m_timetagger_server(nullptr)
       , m_shutting_down(false)
       , m_exit_status(EXIT_ERROR)
     { }
@@ -497,13 +495,10 @@ public:
         m_control_server = &control_server;
     }
 
-    /** Register the data servers with the command handler. */
+    /** Register a data server with the command handler. */
-    void set_data_servers(DataServer& acquisition_server,
+    void add_data_server(DataServer& data_server)
-                          DataServer& timetagger_server)
     {
-        m_acquisition_server = &acquisition_server;
+        m_data_servers.push_back(&data_server);
-        m_timetagger_server = &timetagger_server;
-        m_data_servers = {m_acquisition_server, m_timetagger_server};
     }
 
     /** Return the exit status of the command handler. */
@@ -556,20 +551,17 @@ public:
      * If a multi-threaded Asio event loop is running, this method may only
      * be called through the strand returned by "get_executor()".
      *
-     * The specified response function will be called exactly once to pass
+     * Returns:
-     * the command response (without line terminator). An empty string is
+     *   Response without line terminator,
-     * passed if no response must be sent.
+     *   or an empty string if no response must be sent.
-     *
-     * The call to the response function may be deferred.
      */
-    void handle_command(const std::string& command,
+    std::string handle_command(const std::string& command)
-                        std::function<void(std::string)> respond)
     {
         if (m_shutting_down) {
             // The server is shutting down.
-            // Ignore new commands and send no response.
+            // Ignore new commands and return an empty string to indicate
-            respond(std::string());
+            // that no response must be sent.
-            return;
+            return std::string();
         }
 
         // Split words.
@@ -577,8 +569,7 @@ public:
 
         // Ignore empty command line without response.
         if (tokens.empty()) {
-            respond(std::string());
+            return std::string();
-            return;
         }
 
         // Convert command to lower case.
@@ -593,8 +584,7 @@ public:
                 && action[7] == ':') {
             char channel_digit = action[6];
             if (channel_digit < '1' || channel_digit > '4') {
-                respond(err_unknown_command());
+                return err_unknown_command();
-                return;
             }
             env.channel = channel_digit - '1';
             action[6] = 'N';  // mark channel index
@@ -632,13 +622,10 @@ public:
             const auto it = command_table_no_args.find(action);
             if (it != command_table_no_args.end()) {
                 if (tokens.size() != 1) {
-                    respond(err_unexpected_argument());
+                    return err_unexpected_argument();
-                    return;
                 }
                 auto func = it->second;
-                std::string resp = (this->*func)(env);
+                return (this->*func)(env);
-                respond(resp);
-                return;
             }
         }
 
@@ -647,57 +634,37 @@ public:
             const auto it = command_table_one_arg.find(action);
             if (it != command_table_one_arg.end()) {
                 if (tokens.size() < 2) {
-                    respond(err_missing_argument());
+                    return err_missing_argument();
-                    return;
                 }
                 if (tokens.size() > 2) {
-                    respond(err_unexpected_argument());
+                    return err_unexpected_argument();
-                    return;
                 }
                 auto func = it->second;
-                std::string resp = (this->*func)(env, tokens[1]);
+                return (this->*func)(env, tokens[1]);
-                respond(resp);
-                return;
             }
         }
 
         // Handle command IPCFG.
         if (action == "ipcfg" || action == "ipcfg:saved") {
             if (tokens.size() < 2) {
-                respond(err_missing_argument());
+                return err_missing_argument();
-                return;
             }
             if (tokens.size() > 5) {
-                respond(err_unexpected_argument());
+                return err_unexpected_argument();
-                return;
             }
             tokens.erase(tokens.begin());
-            std::string resp = cmd_ipcfg(env, tokens);
+            return cmd_ipcfg(env, tokens);
-            respond(resp);
-            return;
         }
 
-        // Handle command AIN:CLEAR.
+        return err_unknown_command();
-        if (action == "ain:clear") {
-            cmd_ain_clear(respond);
-            return;
-        }
-
-        // Handle command TT:CLEAR.
-        if (action == "tt:clear") {
-            cmd_tt_clear(respond);
-            return;
-        }
-
-        respond(err_unknown_command());
     }
 
 private:
-    /** Asynchronously stop control and data servers. */
+    /** Asynchronously stop control and/or data servers. */
     void stop_server(std::function<void()> handler);
     void stop_data_servers(unsigned int idx, std::function<void()> handler);
 
-    /** Asynchronously start control and data servers. */
+    /** Asynchronously start control and/or data servers. */
     void start_server();
     void start_data_servers(unsigned int idx);
 
@@ -1398,26 +1365,6 @@ private:
         }
     }
 
-    /** Handle command AIN:CLEAR */
-    void cmd_ain_clear(std::function<void(std::string)> respond)
-    {
-        asio::post(m_acquisition_server->get_executor(),
-            [this,respond]() {
-                m_acquisition_server->clear_data();
-                respond("OK");
-            });
-    }
-
-    /** Handle command TT:CLEAR */
-    void cmd_tt_clear(std::function<void(std::string)> respond)
-    {
-        asio::post(m_timetagger_server->get_executor(),
-            [this,respond]() {
-                m_timetagger_server->clear_data();
-                respond("OK");
-            });
-    }
-
     static const inline std::map<
         std::string,
         std::string (CommandHandler::*)(CommandEnvironment)>
@@ -1489,8 +1436,6 @@ private:
     std::string                 m_model_name;
     std::string                 m_serial_number;
     ControlServer*              m_control_server;
-    DataServer*                 m_acquisition_server;
-    DataServer*                 m_timetagger_server;
     std::vector<DataServer*>    m_data_servers;
     Calibration                 m_calibration;
     bool                        m_shutting_down;
@@ -1770,22 +1715,17 @@ private:
             m_command_handler.get_executor(),
             [this,conn,command]() {
                 // This code runs in the command handler strand.
-
-                // Define helper function which will be called by
-                // the command handler to pass a response.
-                auto respond = [this,conn](std::string response) {
-                    // Post the response back to our own strand.
-                    asio::post(
-                        m_strand,
-                        [this,conn,response]() {
-                            // This code runs in our own strand.
-                            // Handle the response.
-                            process_response(conn, response);
-                        });
-                };
-
                 // Tell the command handler to run the command.
-                m_command_handler.handle_command(command, respond);
+                auto response = m_command_handler.handle_command(command);
+
+                // Post the response back to our own strand.
+                asio::post(
+                    m_strand,
+                    [this,conn,response]() {
+                        // This code runs in our own strand.
+                        // Handle the response.
+                        process_response(conn, response);
+                    });
             });
     }
 
@@ -1938,7 +1878,8 @@ int run_remote_control_server(
     ControlServer control_server(io, command_handler, 5025);
 
     command_handler.set_control_server(control_server);
-    command_handler.set_data_servers(acq_server, timetagger_server);
+    command_handler.add_data_server(acq_server);
+    command_handler.add_data_server(timetagger_server);
 
     // Disable DMA on exit from this function.
     struct ScopeGuard {

sw/src/userspace/version.hpp

@@ -1,2 +1,2 @@
 #define PUZZLEFW_SW_MAJOR 1
-#define PUZZLEFW_SW_MINOR 1
+#define PUZZLEFW_SW_MINOR 0