1 files changed, 206 insertions, 0 deletions
diff --git a/host/lib/usrp/usrp1/soft_time_ctrl.cpp b/host/lib/usrp/usrp1/soft_time_ctrl.cpp
new file mode 100644
index 000000000..1bab34e7b
--- /dev/null
+++ b/host/lib/usrp/usrp1/soft_time_ctrl.cpp
@@ -0,0 +1,206 @@
+//
+// Copyright 2011 Ettus Research LLC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+#include "soft_time_ctrl.hpp"
+#include <uhd/transport/bounded_buffer.hpp>
+#include <boost/any.hpp>
+#include <boost/thread/thread.hpp>
+#include <boost/thread/barrier.hpp>
+#include <boost/thread/condition_variable.hpp>
+#include <boost/date_time/posix_time/posix_time.hpp>
+#include <iostream>
+
+using namespace uhd;
+using namespace uhd::usrp;
+using namespace uhd::transport;
+namespace pt = boost::posix_time;
+
+static const time_spec_t TWIDDLE(0.0011);
+
+/***********************************************************************
+ * Soft time control implementation
+ **********************************************************************/
+class soft_time_ctrl_impl : public soft_time_ctrl{
+public:
+
+    soft_time_ctrl_impl(const cb_fcn_type &stream_on_off):
+        _nsamps_remaining(0),
+        _stream_mode(stream_cmd_t::STREAM_MODE_STOP_CONTINUOUS),
+        _cmd_queue(2),
+        _stream_on_off(stream_on_off)
+    {
+        //synchronously spawn a new thread
+        boost::barrier spawn_barrier(2);
+        _thread_group.create_thread(boost::bind(
+            &soft_time_ctrl_impl::recv_cmd_dispatcher, this, boost::ref(spawn_barrier))
+        );
+        spawn_barrier.wait();
+
+        //initialize the time to something
+        this->set_time(time_spec_t(0.0));
+    }
+
+    ~soft_time_ctrl_impl(void){
+        _thread_group.interrupt_all();
+        _thread_group.join_all();
+    }
+
+    /*******************************************************************
+     * Time control
+     ******************************************************************/
+    void set_time(const time_spec_t &time){
+        boost::mutex::scoped_lock lock(_update_mutex);
+        _time_offset = time_spec_t::get_system_time() - time;
+    }
+
+    time_spec_t get_time(void){
+        boost::mutex::scoped_lock lock(_update_mutex);
+        return time_now();
+    }
+
+    UHD_INLINE time_spec_t time_now(void){
+        //internal get time without scoped lock
+        return time_spec_t::get_system_time() - _time_offset;
+    }
+
+    UHD_INLINE void sleep_until_time(
+        boost::mutex::scoped_lock &lock, const time_spec_t &time
+    ){
+        boost::condition_variable cond;
+        //use a condition variable to unlock, sleep, lock
+        double seconds_to_sleep = (time - time_now()).get_real_secs();
+        cond.timed_wait(lock, pt::microseconds(long(seconds_to_sleep*1e6)));
+    }
+
+    /*******************************************************************
+     * Receive control
+     ******************************************************************/
+    void recv_post(rx_metadata_t &md, size_t &nsamps){
+        boost::mutex::scoped_lock lock(_update_mutex);
+
+        //load the metadata with the expected time
+        md.has_time_spec = true;
+        md.time_spec = time_now();
+
+        //none of the stuff below matters in continuous streaming mode
+        if (_stream_mode == stream_cmd_t::STREAM_MODE_START_CONTINUOUS) return;
+
+        //When to stop streaming:
+        //The samples have been received and the stream mode is non-continuous.
+        //Rewrite the sample count to clip to the requested number of samples.
+        if (_nsamps_remaining <= nsamps){
+            nsamps = _nsamps_remaining; //set nsamps, then stop
+            md.end_of_burst = true;
+            stream_on_off(false);
+            return;
+        }
+
+        //update the consumed samples
+        _nsamps_remaining -= nsamps;
+    }
+
+    void issue_stream_cmd(const stream_cmd_t &cmd){
+        _cmd_queue.push_with_wait(cmd);
+    }
+
+    void stream_on_off(bool enb){
+        _stream_on_off(enb);
+        _nsamps_remaining = 0;
+    }
+
+    /*******************************************************************
+     * Transmit control
+     ******************************************************************/
+    bool send_pre(const tx_metadata_t &md, double &timeout){
+        if (not md.has_time_spec) return false;
+
+        boost::mutex::scoped_lock lock(_update_mutex);
+
+        time_spec_t time_at(md.time_spec - TWIDDLE);
+
+        //handle late packets
+        if (time_at < time_now()){
+            //TODO post async message
+            return true;
+        }
+
+        timeout -= (time_at - time_now()).get_real_secs();
+        sleep_until_time(lock, time_at);
+        return false;
+    }
+
+    /*******************************************************************
+     * Thread control
+     ******************************************************************/
+    void recv_cmd_handle_cmd(const stream_cmd_t &cmd){
+        boost::mutex::scoped_lock lock(_update_mutex);
+
+        //handle the stream at time by sleeping
+        if (not cmd.stream_now){
+            time_spec_t time_at(cmd.time_spec - TWIDDLE);
+            if (time_at < time_now()){
+                //TODO inject late cmd inline error
+            }
+            else{
+                sleep_until_time(lock, time_at);
+            }
+        }
+
+        //When to stop streaming:
+        //Stop streaming when the command is a stop and streaming.
+        if (cmd.stream_mode == stream_cmd_t::STREAM_MODE_STOP_CONTINUOUS
+           and _stream_mode != stream_cmd_t::STREAM_MODE_STOP_CONTINUOUS
+        ) stream_on_off(false);
+
+        //When to start streaming:
+        //Start streaming when the command is not a stop and not streaming.
+        if (cmd.stream_mode != stream_cmd_t::STREAM_MODE_STOP_CONTINUOUS
+           and _stream_mode == stream_cmd_t::STREAM_MODE_STOP_CONTINUOUS
+        ) stream_on_off(true);
+
+        //update the state
+        _nsamps_remaining += cmd.num_samps;
+        _stream_mode = cmd.stream_mode;
+    }
+
+    void recv_cmd_dispatcher(boost::barrier &spawn_barrier){
+        spawn_barrier.wait();
+        try{
+            boost::any cmd;
+            while (true){
+                _cmd_queue.pop_with_wait(cmd);
+                recv_cmd_handle_cmd(boost::any_cast<stream_cmd_t>(cmd));
+            }
+        } catch(const boost::thread_interrupted &){}
+    }
+
+private:
+    boost::mutex _update_mutex;
+    size_t _nsamps_remaining;
+    stream_cmd_t::stream_mode_t _stream_mode;
+    time_spec_t _time_offset;
+    bounded_buffer<boost::any> _cmd_queue;
+    const cb_fcn_type _stream_on_off;
+    boost::thread_group _thread_group;
+};
+
+/***********************************************************************
+ * Soft time control factor
+ **********************************************************************/
+soft_time_ctrl::sptr soft_time_ctrl::make(const cb_fcn_type &stream_on_off){
+    return sptr(new soft_time_ctrl_impl(stream_on_off));
+}