usrp2: restored discovery and most of io_impl

8 files changed, 597 insertions, 21 deletions

diff --git a/host/lib/property_tree.cpp b/host/lib/property_tree.cpp
index 7cda7a524..4fbdbad12 100644
--- a/host/lib/property_tree.cpp
+++ b/host/lib/property_tree.cpp
@@ -49,7 +49,7 @@ public:
         return true;
     }
 
-    iterator_type iterate(const path_type &path){
+    std::vector<std::string> list(const path_type &path){
         boost::mutex::scoped_lock lock(_mutex);
 
         node_type *node = &_root;
@@ -58,11 +58,7 @@ public:
             node = &(*node)[leaf];
         }
 
-        iterator_type iter;
-        BOOST_FOREACH(const std::string &name, node->keys()){
-            iter.push_back(name);
-        }
-        return iter;
+        return node->keys();
     }
 
     void _create(const path_type &path, const boost::any &prop){
diff --git a/host/lib/usrp/CMakeLists.txt b/host/lib/usrp/CMakeLists.txt
index 32ba79fbb..554da369e 100644
--- a/host/lib/usrp/CMakeLists.txt
+++ b/host/lib/usrp/CMakeLists.txt
@@ -36,7 +36,7 @@ LIBUHD_APPEND_SOURCES(
 INCLUDE_SUBDIRECTORY(cores)
 INCLUDE_SUBDIRECTORY(dboard)
 INCLUDE_SUBDIRECTORY(fx2)
-INCLUDE_SUBDIRECTORY(usrp1)
+#INCLUDE_SUBDIRECTORY(usrp1)
 #INCLUDE_SUBDIRECTORY(usrp2)
-INCLUDE_SUBDIRECTORY(b100)
-INCLUDE_SUBDIRECTORY(e100)
+#INCLUDE_SUBDIRECTORY(b100)
+#INCLUDE_SUBDIRECTORY(e100)
diff --git a/host/lib/usrp/dboard/db_basic_and_lf.cpp b/host/lib/usrp/dboard/db_basic_and_lf.cpp
index 566e24d97..05c989a97 100644
--- a/host/lib/usrp/dboard/db_basic_and_lf.cpp
+++ b/host/lib/usrp/dboard/db_basic_and_lf.cpp
@@ -162,6 +162,10 @@ void basic_rx::rx_get(const wax::obj &key_, wax::obj &val){
         val = prop_names_t(1, ""); //vector of 1 empty string
         return;
 
+    case SUBDEV_PROP_SENSOR_NAMES:
+        val = prop_names_t(1, ""); //vector of 1 empty string
+        return;
+
     case SUBDEV_PROP_CONNECTION:
         val = sd_name_to_conn[get_subdev_name()];
         return;
@@ -268,6 +272,10 @@ void basic_tx::tx_get(const wax::obj &key_, wax::obj &val){
         val = prop_names_t(1, ""); //vector of 1 empty string
         return;
 
+    case SUBDEV_PROP_SENSOR_NAMES:
+        val = prop_names_t(1, ""); //vector of 1 empty string
+        return;
+
     case SUBDEV_PROP_CONNECTION:
         val = sd_name_to_conn[get_subdev_name()];
         return;
diff --git a/host/lib/usrp/dboard/db_unknown.cpp b/host/lib/usrp/dboard/db_unknown.cpp
index 6cacab231..19f0f1c71 100644
--- a/host/lib/usrp/dboard/db_unknown.cpp
+++ b/host/lib/usrp/dboard/db_unknown.cpp
@@ -142,6 +142,10 @@ void unknown_rx::rx_get(const wax::obj &key_, wax::obj &val){
         val = prop_names_t(1, ""); //vector of 1 empty string
         return;
 
+    case SUBDEV_PROP_SENSOR_NAMES:
+        val = prop_names_t(1, ""); //vector of 1 empty string
+        return;
+
     case SUBDEV_PROP_CONNECTION:
         val = SUBDEV_CONN_COMPLEX_IQ;
         return;
@@ -238,6 +242,10 @@ void unknown_tx::tx_get(const wax::obj &key_, wax::obj &val){
         val = prop_names_t(1, ""); //vector of 1 empty string
         return;
 
+    case SUBDEV_PROP_SENSOR_NAMES:
+        val = prop_names_t(1, ""); //vector of 1 empty string
+        return;
+
     case SUBDEV_PROP_CONNECTION:
         val = SUBDEV_CONN_COMPLEX_IQ;
         return;
diff --git a/host/lib/usrp2/CMakeLists.txt b/host/lib/usrp2/CMakeLists.txt
index 7a0157f00..d16976060 100644
--- a/host/lib/usrp2/CMakeLists.txt
+++ b/host/lib/usrp2/CMakeLists.txt
@@ -20,15 +20,9 @@
 ########################################################################
 LIBUHD_APPEND_SOURCES(
     ${CMAKE_CURRENT_SOURCE_DIR}/clock_ctrl.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/clock_ctrl.hpp
     ${CMAKE_CURRENT_SOURCE_DIR}/codec_ctrl.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/codec_ctrl.hpp
     ${CMAKE_CURRENT_SOURCE_DIR}/dboard_iface.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/fw_common.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/io_impl.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/usrp2_iface.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/usrp2_iface.hpp
     ${CMAKE_CURRENT_SOURCE_DIR}/usrp2_impl.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/usrp2_impl.hpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/usrp2_regs.hpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/usrp2_clk_regs.hpp
 )
diff --git a/host/lib/usrp2/io_impl.cpp b/host/lib/usrp2/io_impl.cpp
new file mode 100644
index 000000000..9f0792d53
--- /dev/null
+++ b/host/lib/usrp2/io_impl.cpp
@@ -0,0 +1,414 @@
+//
+// Copyright 2010-2011 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 "../../transport/super_recv_packet_handler.hpp"
+#include "../../transport/super_send_packet_handler.hpp"
+#include "usrp2_impl.hpp"
+#include "usrp2_regs.hpp"
+#include <uhd/utils/log.hpp>
+#include <uhd/utils/msg.hpp>
+#include <uhd/exception.hpp>
+#include <uhd/usrp/mboard_props.hpp>
+#include <uhd/usrp/dsp_props.hpp>
+#include <uhd/utils/byteswap.hpp>
+#include <uhd/utils/thread_priority.hpp>
+#include <uhd/transport/bounded_buffer.hpp>
+#include <boost/format.hpp>
+#include <boost/bind.hpp>
+#include <boost/thread/mutex.hpp>
+#include <boost/thread/thread.hpp>
+#include <boost/thread/barrier.hpp>
+#include <numeric>
+#include <iostream>
+
+using namespace uhd;
+using namespace uhd::usrp;
+using namespace uhd::transport;
+namespace asio = boost::asio;
+namespace pt = boost::posix_time;
+
+/***********************************************************************
+ * helpers
+ **********************************************************************/
+static UHD_INLINE pt::time_duration to_time_dur(double timeout){
+    return pt::microseconds(long(timeout*1e6));
+}
+
+static UHD_INLINE double from_time_dur(const pt::time_duration &time_dur){
+    return 1e-6*time_dur.total_microseconds();
+}
+
+/***********************************************************************
+ * constants
+ **********************************************************************/
+static const int underflow_flags = 0
+    | async_metadata_t::EVENT_CODE_UNDERFLOW
+    | async_metadata_t::EVENT_CODE_UNDERFLOW_IN_PACKET
+;
+
+static const size_t vrt_send_header_offset_words32 = 1;
+
+/***********************************************************************
+ * flow control monitor for a single tx channel
+ *  - the pirate thread calls update
+ *  - the get send buffer calls check
+ **********************************************************************/
+class flow_control_monitor{
+public:
+    typedef boost::uint32_t seq_type;
+    typedef boost::shared_ptr<flow_control_monitor> sptr;
+
+    /*!
+     * Make a new flow control monitor.
+     * \param max_seqs_out num seqs before throttling
+     */
+    flow_control_monitor(seq_type max_seqs_out){
+        _last_seq_out = 0;
+        _last_seq_ack = 0;
+        _max_seqs_out = max_seqs_out;
+        _ready_fcn = boost::bind(&flow_control_monitor::ready, this);
+    }
+
+    /*!
+     * Gets the current sequence number to go out.
+     * Increments the sequence for the next call
+     * \return the sequence to be sent to the dsp
+     */
+    UHD_INLINE seq_type get_curr_seq_out(void){
+        return _last_seq_out++;
+    }
+
+    /*!
+     * Check the flow control condition.
+     * \param timeout the timeout in seconds
+     * \return false on timeout
+     */
+    UHD_INLINE bool check_fc_condition(double timeout){
+        boost::mutex::scoped_lock lock(_fc_mutex);
+        if (this->ready()) return true;
+        boost::this_thread::disable_interruption di; //disable because the wait can throw
+        return _fc_cond.timed_wait(lock, to_time_dur(timeout), _ready_fcn);
+    }
+
+    /*!
+     * Update the flow control condition.
+     * \param seq the last sequence number to be ACK'd
+     */
+    UHD_INLINE void update_fc_condition(seq_type seq){
+        boost::mutex::scoped_lock lock(_fc_mutex);
+        _last_seq_ack = seq;
+        lock.unlock();
+        _fc_cond.notify_one();
+    }
+
+private:
+    bool ready(void){
+        return seq_type(_last_seq_out -_last_seq_ack) < _max_seqs_out;
+    }
+
+    boost::mutex _fc_mutex;
+    boost::condition _fc_cond;
+    seq_type _last_seq_out, _last_seq_ack, _max_seqs_out;
+    boost::function<bool(void)> _ready_fcn;
+};
+
+/***********************************************************************
+ * io impl details (internal to this file)
+ * - pirate crew
+ * - alignment buffer
+ * - thread loop
+ * - vrt packet handler states
+ **********************************************************************/
+struct usrp2_impl::io_impl{
+
+    io_impl(const size_t mboards):
+        rx_chan_occ(mboards), tx_chan_occ(mboards),
+        async_msg_fifo(100/*messages deep*/)
+    {
+        /* NOP */
+    }
+
+    ~io_impl(void){
+        recv_pirate_crew.interrupt_all();
+        recv_pirate_crew.join_all();
+    }
+
+    managed_send_buffer::sptr get_send_buff(size_t chan, double timeout){
+        flow_control_monitor &fc_mon = *fc_mons[chan];
+
+        //wait on flow control w/ timeout
+        if (not fc_mon.check_fc_condition(timeout)) return managed_send_buffer::sptr();
+
+        //get a buffer from the transport w/ timeout
+        managed_send_buffer::sptr buff = tx_xports[chan]->get_send_buff(timeout);
+
+        //write the flow control word into the buffer
+        if (buff.get()) buff->cast<boost::uint32_t *>()[0] = uhd::htonx(fc_mon.get_curr_seq_out());
+
+        return buff;
+    }
+
+    //subdev spec mapping information
+    std::vector<size_t> rx_chan_occ, tx_chan_occ;
+
+    //tx dsp: xports and flow control monitors
+    std::vector<zero_copy_if::sptr> tx_xports;
+    std::vector<flow_control_monitor::sptr> fc_mons;
+
+    //state management for the vrt packet handler code
+    sph::recv_packet_handler recv_handler;
+    sph::send_packet_handler send_handler;
+
+    //methods and variables for the pirate crew
+    void recv_pirate_loop(boost::barrier &, zero_copy_if::sptr, size_t);
+    boost::thread_group recv_pirate_crew;
+    bounded_buffer<async_metadata_t> async_msg_fifo;
+    double tick_rate;
+};
+
+/***********************************************************************
+ * Receive Pirate Loop
+ * - while raiding, loot for message packet
+ * - update flow control condition count
+ * - put async message packets into queue
+ **********************************************************************/
+void usrp2_impl::io_impl::recv_pirate_loop(
+    boost::barrier &spawn_barrier,
+    zero_copy_if::sptr err_xport,
+    size_t index
+){
+    spawn_barrier.wait();
+    set_thread_priority_safe();
+
+    //store a reference to the flow control monitor (offset by max dsps)
+    flow_control_monitor &fc_mon = *(this->fc_mons[index]);
+
+    while (not boost::this_thread::interruption_requested()){
+        managed_recv_buffer::sptr buff = err_xport->get_recv_buff();
+        if (not buff.get()) continue; //ignore timeout/error buffers
+
+        try{
+            //extract the vrt header packet info
+            vrt::if_packet_info_t if_packet_info;
+            if_packet_info.num_packet_words32 = buff->size()/sizeof(boost::uint32_t);
+            const boost::uint32_t *vrt_hdr = buff->cast<const boost::uint32_t *>();
+            vrt::if_hdr_unpack_be(vrt_hdr, if_packet_info);
+
+            //handle a tx async report message
+            if (if_packet_info.sid == USRP2_TX_ASYNC_SID and if_packet_info.packet_type != vrt::if_packet_info_t::PACKET_TYPE_DATA){
+
+                //fill in the async metadata
+                async_metadata_t metadata;
+                metadata.channel = index;
+                metadata.has_time_spec = if_packet_info.has_tsi and if_packet_info.has_tsf;
+                metadata.time_spec = time_spec_t(
+                    time_t(if_packet_info.tsi), size_t(if_packet_info.tsf), tick_rate
+                );
+                metadata.event_code = async_metadata_t::event_code_t(sph::get_context_code(vrt_hdr, if_packet_info));
+
+                //catch the flow control packets and react
+                if (metadata.event_code == 0){
+                    boost::uint32_t fc_word32 = (vrt_hdr + if_packet_info.num_header_words32)[1];
+                    fc_mon.update_fc_condition(uhd::ntohx(fc_word32));
+                    continue;
+                }
+
+                //print the famous U, and push the metadata into the message queue
+                if (metadata.event_code & underflow_flags) UHD_MSG(fastpath) << "U";
+                //else UHD_MSG(often) << "metadata.event_code " << metadata.event_code << std::endl;
+                async_msg_fifo.push_with_pop_on_full(metadata);
+            }
+            else{
+                //TODO unknown received packet, may want to print error...
+            }
+        }catch(const std::exception &e){
+            UHD_MSG(error) << "Error (usrp2 recv pirate loop): " << e.what() << std::endl;
+        }
+    }
+}
+
+/***********************************************************************
+ * Helper Functions
+ **********************************************************************/
+void usrp2_impl::io_init(void){
+
+    //TODO //This is a hack/fix for the lingering packet problem.
+
+    //create new io impl
+    _io_impl = UHD_PIMPL_MAKE(io_impl, (_mboard_stuff.size()));
+
+    //init first so we dont have an access race
+    for (size_t i = 0; i < _mboard_stuff.size(); i++){
+        //init the tx xport and flow control monitor
+        _io_impl->tx_xports.push_back(_mboard_stuff[i].dsp_xports.at(0));
+        _io_impl->fc_mons.push_back(flow_control_monitor::sptr(new flow_control_monitor(
+            USRP2_SRAM_BYTES/_mboard_stuff[i].dsp_xports.at(0)->get_send_frame_size()
+        )));
+    }
+
+    //create a new pirate thread for each zc if (yarr!!)
+    boost::barrier spawn_barrier(_mboard_stuff.size()+1);
+    for (size_t i = 0; i < _mboard_stuff.size(); i++){
+        //spawn a new pirate to plunder the recv booty
+        _io_impl->recv_pirate_crew.create_thread(boost::bind(
+            &usrp2_impl::io_impl::recv_pirate_loop,
+            _io_impl.get(), boost::ref(spawn_barrier),
+            _mboard_stuff[i].err_xports.at(0), i
+        ));
+    }
+    spawn_barrier.wait();
+
+    //init some handler stuff
+    _io_impl->recv_handler.set_vrt_unpacker(&vrt::if_hdr_unpack_be);
+    _io_impl->recv_handler.set_converter(_rx_otw_type);
+    _io_impl->send_handler.set_vrt_packer(&vrt::if_hdr_pack_be, vrt_send_header_offset_words32);
+    _io_impl->send_handler.set_converter(_tx_otw_type);
+    _io_impl->send_handler.set_max_samples_per_packet(get_max_send_samps_per_packet());
+}
+
+void usrp2_impl::update_tick_rate(const double rate){
+    _io_impl->tick_rate = rate;
+    boost::mutex::scoped_lock recv_lock = _io_impl->recv_handler.get_scoped_lock();
+    _io_impl->recv_handler.set_tick_rate(rate);
+    boost::mutex::scoped_lock send_lock = _io_impl->send_handler.get_scoped_lock();
+    _io_impl->send_handler.set_tick_rate(rate);
+}
+
+void usrp2_impl::update_rx_samp_rate(const double rate){
+    boost::mutex::scoped_lock recv_lock = _io_impl->recv_handler.get_scoped_lock();
+    _io_impl->recv_handler.set_samp_rate(rate);
+}
+
+void usrp2_impl::update_tx_samp_rate(const double rate){
+    boost::mutex::scoped_lock send_lock = _io_impl->send_handler.get_scoped_lock();
+    _io_impl->send_handler.set_samp_rate(rate);
+}
+
+void usrp2_impl::update_rx_subdev_spec(const size_t which_mb, const subdev_spec_t &spec){
+    boost::mutex::scoped_lock recv_lock = _io_impl->recv_handler.get_scoped_lock();
+
+    //TODO setup mux for this spec
+
+    //compute the new occupancy and resize
+    _io_impl->rx_chan_occ[which_mb] = spec.size();
+    const size_t nchan = std::accumulate(_io_impl->rx_chan_occ.begin(), _io_impl->rx_chan_occ.end(), 0);
+    _io_impl->recv_handler.resize(nchan);
+
+    //bind new callbacks for the handler
+    size_t chan = 0;
+    for (size_t mb = 0; mb < _mboard_stuff.size(); mb++){
+        for (size_t dsp = 0; dsp < _io_impl->rx_chan_occ[mb]; dsp++){
+            _io_impl->recv_handler.set_xport_chan_get_buff(chan++, boost::bind(
+                &zero_copy_if::get_recv_buff, _mboard_stuff[mb].dsp_xports[dsp], _1
+            ));
+        }
+    }
+}
+
+void usrp2_impl::update_tx_subdev_spec(const size_t which_mb, const subdev_spec_t &spec_){
+    boost::mutex::scoped_lock send_lock = _io_impl->send_handler.get_scoped_lock();
+    property_tree::path_type root = str(boost::format("/mboards/%u/dboards") % which_mb);
+
+    //sanity checking
+    subdev_spec_t spec(spec_);
+    if (spec.size() == 0){
+        //determine the first subdev spec that exists
+        const std::string db_name = _tree->list(root).at(0);
+        const std::string sd_name = _tree->list(root / db_name / "tx_frontends").at(0);
+        spec.push_back(db_name + ":" + sd_name);
+    }
+    if (spec.size() != 1) throw uhd::value_error("tx subdev spec has to be size 1");
+
+    //set the mux for this spec
+    const std::string conn = _tree->access<std::string>(root / spec[0].db_name / "tx_frontends" / spec[0].sd_name / "connection").get();
+    _mboard_stuff[which_mb].tx_fe->set_mux(conn);
+
+    //compute the new occupancy and resize
+    _io_impl->tx_chan_occ[which_mb] = spec.size();
+    const size_t nchan = std::accumulate(_io_impl->tx_chan_occ.begin(), _io_impl->tx_chan_occ.end(), 0);
+    _io_impl->send_handler.resize(nchan);
+
+    //bind new callbacks for the handler
+    size_t chan = 0;
+    for (size_t mb = 0; mb < _mboard_stuff.size(); mb++){
+        for (size_t dsp = 0; dsp < _io_impl->tx_chan_occ[mb]; dsp++){
+            _io_impl->send_handler.set_xport_chan_get_buff(chan++, boost::bind(
+                &usrp2_impl::io_impl::get_send_buff, _io_impl.get(), mb, _1
+            ));
+        }
+    }
+}
+
+/***********************************************************************
+ * Async Data
+ **********************************************************************/
+bool usrp2_impl::recv_async_msg(
+    async_metadata_t &async_metadata, double timeout
+){
+    boost::this_thread::disable_interruption di; //disable because the wait can throw
+    return _io_impl->async_msg_fifo.pop_with_timed_wait(async_metadata, timeout);
+}
+
+/***********************************************************************
+ * Send Data
+ **********************************************************************/
+size_t usrp2_impl::get_max_send_samps_per_packet(void) const{
+    static const size_t hdr_size = 0
+        + vrt::max_if_hdr_words32*sizeof(boost::uint32_t)
+        + vrt_send_header_offset_words32*sizeof(boost::uint32_t)
+        - sizeof(vrt::if_packet_info_t().cid) //no class id ever used
+    ;
+    const size_t bpp = _mboard_stuff[0].dsp_xports[0]->get_send_frame_size() - hdr_size;
+    return bpp/_tx_otw_type.get_sample_size();
+}
+
+size_t usrp2_impl::send(
+    const send_buffs_type &buffs, size_t nsamps_per_buff,
+    const tx_metadata_t &metadata, const io_type_t &io_type,
+    send_mode_t send_mode, double timeout
+){
+    return _io_impl->send_handler.send(
+        buffs, nsamps_per_buff,
+        metadata, io_type,
+        send_mode, timeout
+    );
+}
+
+/***********************************************************************
+ * Receive Data
+ **********************************************************************/
+size_t usrp2_impl::get_max_recv_samps_per_packet(void) const{
+    static const size_t hdr_size = 0
+        + vrt::max_if_hdr_words32*sizeof(boost::uint32_t)
+        + sizeof(vrt::if_packet_info_t().tlr) //forced to have trailer
+        - sizeof(vrt::if_packet_info_t().cid) //no class id ever used
+    ;
+    const size_t bpp = _mboard_stuff[0].dsp_xports[0]->get_recv_frame_size() - hdr_size;
+    return bpp/_rx_otw_type.get_sample_size();
+}
+
+size_t usrp2_impl::recv(
+    const recv_buffs_type &buffs, size_t nsamps_per_buff,
+    rx_metadata_t &metadata, const io_type_t &io_type,
+    recv_mode_t recv_mode, double timeout
+){
+    return _io_impl->recv_handler.recv(
+        buffs, nsamps_per_buff,
+        metadata, io_type,
+        recv_mode, timeout
+    );
+}
diff --git a/host/lib/usrp2/usrp2_impl.cpp b/host/lib/usrp2/usrp2_impl.cpp
index 3e39b7d23..cbe4a7dba 100644
--- a/host/lib/usrp2/usrp2_impl.cpp
+++ b/host/lib/usrp2/usrp2_impl.cpp
@@ -40,6 +40,123 @@ using namespace uhd::transport;
 namespace asio = boost::asio;
 
 /***********************************************************************
+ * Discovery over the udp transport
+ **********************************************************************/
+static device_addrs_t usrp2_find(const device_addr_t &hint_){
+    //handle the multi-device discovery
+    device_addrs_t hints = separate_device_addr(hint_);
+    if (hints.size() > 1){
+        device_addrs_t found_devices;
+        BOOST_FOREACH(const device_addr_t &hint_i, hints){
+            device_addrs_t found_devices_i = usrp2_find(hint_i);
+            if (found_devices_i.size() != 1) throw uhd::value_error(str(boost::format(
+                "Could not resolve device hint \"%s\" to a single device."
+            ) % hint_i.to_string()));
+            found_devices.push_back(found_devices_i[0]);
+        }
+        return device_addrs_t(1, combine_device_addrs(found_devices));
+    }
+
+    //initialize the hint for a single device case
+    UHD_ASSERT_THROW(hints.size() <= 1);
+    hints.resize(1); //in case it was empty
+    device_addr_t hint = hints[0];
+    device_addrs_t usrp2_addrs;
+
+    //return an empty list of addresses when type is set to non-usrp2
+    if (hint.has_key("type") and hint["type"] != "usrp2") return usrp2_addrs;
+
+    //if no address was specified, send a broadcast on each interface
+    if (not hint.has_key("addr")){
+        BOOST_FOREACH(const if_addrs_t &if_addrs, get_if_addrs()){
+            //avoid the loopback device
+            if (if_addrs.inet == asio::ip::address_v4::loopback().to_string()) continue;
+
+            //create a new hint with this broadcast address
+            device_addr_t new_hint = hint;
+            new_hint["addr"] = if_addrs.bcast;
+
+            //call discover with the new hint and append results
+            device_addrs_t new_usrp2_addrs = usrp2_find(new_hint);
+            usrp2_addrs.insert(usrp2_addrs.begin(),
+                new_usrp2_addrs.begin(), new_usrp2_addrs.end()
+            );
+        }
+        return usrp2_addrs;
+    }
+
+    //create a udp transport to communicate
+    std::string ctrl_port = boost::lexical_cast<std::string>(USRP2_UDP_CTRL_PORT);
+    udp_simple::sptr udp_transport = udp_simple::make_broadcast(
+        hint["addr"], ctrl_port
+    );
+
+    //send a hello control packet
+    usrp2_ctrl_data_t ctrl_data_out = usrp2_ctrl_data_t();
+    ctrl_data_out.proto_ver = uhd::htonx<boost::uint32_t>(USRP2_FW_COMPAT_NUM);
+    ctrl_data_out.id = uhd::htonx<boost::uint32_t>(USRP2_CTRL_ID_WAZZUP_BRO);
+    udp_transport->send(boost::asio::buffer(&ctrl_data_out, sizeof(ctrl_data_out)));
+
+    //loop and recieve until the timeout
+    boost::uint8_t usrp2_ctrl_data_in_mem[udp_simple::mtu]; //allocate max bytes for recv
+    const usrp2_ctrl_data_t *ctrl_data_in = reinterpret_cast<const usrp2_ctrl_data_t *>(usrp2_ctrl_data_in_mem);
+    while(true){
+        size_t len = udp_transport->recv(asio::buffer(usrp2_ctrl_data_in_mem));
+        if (len > offsetof(usrp2_ctrl_data_t, data) and ntohl(ctrl_data_in->id) == USRP2_CTRL_ID_WAZZUP_DUDE){
+
+            //make a boost asio ipv4 with the raw addr in host byte order
+            boost::asio::ip::address_v4 ip_addr(ntohl(ctrl_data_in->data.ip_addr));
+            device_addr_t new_addr;
+            new_addr["type"] = "usrp2";
+            new_addr["addr"] = ip_addr.to_string();
+
+            //Attempt to read the name from the EEPROM and perform filtering.
+            //This operation can throw due to compatibility mismatch.
+            try{
+                usrp2_iface::sptr iface = usrp2_iface::make(udp_simple::make_connected(
+                    new_addr["addr"], BOOST_STRINGIZE(USRP2_UDP_CTRL_PORT)
+                ));
+                if (iface->is_device_locked()) continue; //ignore locked devices
+                mboard_eeprom_t mb_eeprom = iface->mb_eeprom;
+                new_addr["name"] = mb_eeprom["name"];
+                new_addr["serial"] = mb_eeprom["serial"];
+            }
+            catch(const std::exception &){
+                //set these values as empty string so the device may still be found
+                //and the filter's below can still operate on the discovered device
+                new_addr["name"] = "";
+                new_addr["serial"] = "";
+            }
+
+            //filter the discovered device below by matching optional keys
+            if (
+                (not hint.has_key("name")   or hint["name"]   == new_addr["name"]) and
+                (not hint.has_key("serial") or hint["serial"] == new_addr["serial"])
+            ){
+                usrp2_addrs.push_back(new_addr);
+            }
+
+            //dont break here, it will exit the while loop
+            //just continue on to the next loop iteration
+        }
+        if (len == 0) break; //timeout
+    }
+
+    return usrp2_addrs;
+}
+
+/***********************************************************************
+ * Make
+ **********************************************************************/
+static device::sptr usrp2_make(const device_addr_t &device_addr){
+    return device::sptr(new usrp2_impl(device_addr));
+}
+
+UHD_STATIC_BLOCK(register_usrp2_device){
+    device::register_device(&usrp2_find, &usrp2_make);
+}
+
+/***********************************************************************
  * MTU Discovery
  **********************************************************************/
 struct mtu_result_t{
@@ -291,6 +408,7 @@ usrp2_impl::usrp2_impl(const device_addr_t &_device_addr){
         //TODO //initialize VITA time to GPS time
 
         //TODO clock source, time source
+        //and if gps is present, set to external automatically
 
 
 
@@ -313,10 +431,10 @@ usrp2_impl::usrp2_impl(const device_addr_t &_device_addr){
         // create dsp control objects
         ////////////////////////////////////////////////////////////////
         _mboard_stuff[mb].rx_dsps.push_back(rx_dsp_core_200::make(
-            _mboard_stuff[mb].iface, U2_REG_SR_ADDR(SR_RX_DSP0), U2_REG_SR_ADDR(SR_RX_CTRL0), 3
+            _mboard_stuff[mb].iface, U2_REG_SR_ADDR(SR_RX_DSP0), U2_REG_SR_ADDR(SR_RX_CTRL0), USRP2_RX_SID_BASE + 0
         ));
         _mboard_stuff[mb].rx_dsps.push_back(rx_dsp_core_200::make(
-            _mboard_stuff[mb].iface, U2_REG_SR_ADDR(SR_RX_DSP1), U2_REG_SR_ADDR(SR_RX_CTRL1), 4
+            _mboard_stuff[mb].iface, U2_REG_SR_ADDR(SR_RX_DSP1), U2_REG_SR_ADDR(SR_RX_CTRL1), USRP2_RX_SID_BASE + 1
         ));
         for (size_t dspno = 0; dspno < _mboard_stuff[mb].rx_dsps.size(); dspno++){
             _mboard_stuff[mb].rx_dsps[dspno]->set_tick_rate(tick_rate); //does not change on usrp2
@@ -327,9 +445,10 @@ usrp2_impl::usrp2_impl(const device_addr_t &_device_addr){
             freq_prop.subscribe_master(boost::bind(&rx_dsp_core_200::set_freq, _mboard_stuff[mb].rx_dsps[dspno], _1));
             _tree->create(rx_dsp_path / "freq/value", freq_prop);
             //TODO set nsamps per packet
+            //TODO stream command issue
         }
         _mboard_stuff[mb].tx_dsp = tx_dsp_core_200::make(
-            _mboard_stuff[mb].iface, U2_REG_SR_ADDR(SR_TX_DSP), U2_REG_SR_ADDR(SR_TX_CTRL), 2
+            _mboard_stuff[mb].iface, U2_REG_SR_ADDR(SR_TX_DSP), U2_REG_SR_ADDR(SR_TX_CTRL), USRP2_TX_ASYNC_SID
         );
         _mboard_stuff[mb].tx_dsp->set_tick_rate(tick_rate); //does not change on usrp2
         property<double> tx_dsp_host_rate_prop, tx_dsp_freq_prop;
@@ -407,6 +526,11 @@ usrp2_impl::usrp2_impl(const device_addr_t &_device_addr){
             );
         }
     }
+
+    //TODO io init
+    //TODO subdev spec init
+    //TODO tick rate init
+
 }
 
 usrp2_impl::~usrp2_impl(void){UHD_SAFE_CALL(
diff --git a/host/lib/usrp2/usrp2_impl.hpp b/host/lib/usrp2/usrp2_impl.hpp
index 47fc10d8d..a26ab455d 100644
--- a/host/lib/usrp2/usrp2_impl.hpp
+++ b/host/lib/usrp2/usrp2_impl.hpp
@@ -47,6 +47,8 @@ static const double mimo_clock_delay_usrp2_rev4 = 4.18e-9;
 static const double mimo_clock_delay_usrp_n2xx = 3.55e-9;
 static const size_t mimo_clock_sync_delay_cycles = 137;
 static const size_t USRP2_SRAM_BYTES = size_t(1 << 20);
+static const boost::uint32_t USRP2_TX_ASYNC_SID = 2;
+static const boost::uint32_t USRP2_RX_SID_BASE = 3;
 
 /*!
  * Make a usrp2 dboard interface.
@@ -64,12 +66,28 @@ uhd::usrp::dboard_iface::sptr make_usrp2_dboard_iface(
  * The implementation details are encapsulated here.
  * Handles device properties and streaming...
  */
-class usrp2_impl{
+class usrp2_impl : public uhd::device{
 public:
     usrp2_impl(const uhd::device_addr_t &);
     ~usrp2_impl(void);
-    uhd::property_tree::sptr _tree;
+
+    //the io interface
+    size_t send(
+        const send_buffs_type &, size_t,
+        const uhd::tx_metadata_t &, const uhd::io_type_t &,
+        uhd::device::send_mode_t, double
+    );
+    size_t recv(
+        const recv_buffs_type &, size_t,
+        uhd::rx_metadata_t &, const uhd::io_type_t &,
+        uhd::device::recv_mode_t, double
+    );
+    size_t get_max_send_samps_per_packet(void) const;
+    size_t get_max_recv_samps_per_packet(void) const;
+    bool recv_async_msg(uhd::async_metadata_t &, double);
+
 private:
+    uhd::property_tree::sptr _tree;
     struct mboard_stuff_type{
         usrp2_iface::sptr iface;
         usrp2_clock_ctrl::sptr clock;
@@ -93,6 +111,20 @@ private:
     uhd::sensor_value_t get_mimo_locked(const size_t which_mb);
     uhd::sensor_value_t get_ref_locked(const size_t which_mb);
 
+    //device properties interface
+    void get(const wax::obj &, wax::obj &val){
+        val = _tree; //entry point into property tree
+    }
+
+    //io impl methods and members
+    uhd::otw_type_t _rx_otw_type, _tx_otw_type;
+    UHD_PIMPL_DECL(io_impl) _io_impl;
+    void io_init(void);
+    void update_tick_rate(const double rate);
+    void update_rx_samp_rate(const double rate);
+    void update_tx_samp_rate(const double rate);
+    void update_rx_subdev_spec(const size_t, const uhd::usrp::subdev_spec_t &);
+    void update_tx_subdev_spec(const size_t, const uhd::usrp::subdev_spec_t &);
 };
 
 #endif /* INCLUDED_USRP2_IMPL_HPP */