path: root/host/lib/rfnoc/legacy_compat.cpp

//
// Copyright 2016 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 "legacy_compat.hpp"
#include <uhd/property_tree.hpp>
#include <uhd/rfnoc/radio_ctrl.hpp>
#include <uhd/rfnoc/ddc_block_ctrl.hpp>
#include <uhd/rfnoc/graph.hpp>
#include <uhd/usrp/subdev_spec.hpp>
#include <uhd/stream.hpp>
#include <uhd/types/stream_cmd.hpp>
#include <uhd/types/direction.hpp>
#include <uhd/types/ranges.hpp>
#include <uhd/utils/msg.hpp>
#include <uhd/utils/log.hpp>
#include <uhd/transport/chdr.hpp>
#include <boost/make_shared.hpp>

#define UHD_LEGACY_LOG() UHD_LOGV(never)

using namespace uhd::rfnoc;
using uhd::usrp::subdev_spec_t;
using uhd::usrp::subdev_spec_pair_t;
using uhd::stream_cmd_t;

/************************************************************************
 * Constants
 ***********************************************************************/
static const std::string RADIO_BLOCK_NAME = "Radio";
static const std::string DFIFO_BLOCK_NAME = "DmaFIFO";
static const std::string DDC_BLOCK_NAME = "DDC";
static const std::string DUC_BLOCK_NAME = "DUC";
static const size_t MAX_BYTES_PER_HEADER =
        uhd::transport::vrt::chdr::max_if_hdr_words64 * sizeof(uint64_t);
static const size_t BYTES_PER_SAMPLE = 4; // We currently only support sc16

/************************************************************************
 * Static helpers
 ***********************************************************************/
static uhd::fs_path mb_root(const size_t mboard)
{
    return uhd::fs_path("/mboards") / mboard;
}

size_t num_ports(const uhd::property_tree::sptr &tree, const std::string &block_name, const std::string &in_out)
{
    return tree->list(
            uhd::fs_path("/mboards/0/xbar") /
            str(boost::format("%s_0") % block_name) /
            "ports" / in_out
    ).size();
}

size_t calc_num_tx_chans_per_radio(
    const uhd::property_tree::sptr &tree,
    const size_t num_radios_per_board,
    const bool has_ducs,
    const bool has_dmafifo
) {
    const size_t num_radio_ports = num_ports(tree, RADIO_BLOCK_NAME, "in");
    if (has_ducs) {
        return std::min(
            num_radio_ports,
            num_ports(tree, DUC_BLOCK_NAME, "in")
        );
    }

    if (not has_dmafifo) {
        return num_radio_ports;
    }

    const size_t num_dmafifo_ports_per_radio = num_ports(tree, DFIFO_BLOCK_NAME, "in") / num_radios_per_board;
    UHD_ASSERT_THROW(num_dmafifo_ports_per_radio);

    return std::min(
        num_radio_ports,
        num_dmafifo_ports_per_radio
    );
}

double lambda_const_double(const double d)
{
    return d;
}

uhd::meta_range_t lambda_const_meta_range(const double start, const double stop, const double step)
{
    return uhd::meta_range_t(start, stop, step);
}
/************************************************************************
 * Class Definition
 ***********************************************************************/
class legacy_compat_impl : public legacy_compat
{
public:
    /************************************************************************
     * Structors and Initialization
     ***********************************************************************/
    legacy_compat_impl(
            uhd::device3::sptr device,
            const uhd::device_addr_t &args
    ) : _device(device),
        _tree(device->get_tree()),
        _has_ducs(not args.has_key("skip_duc") and not device->find_blocks(DUC_BLOCK_NAME).empty()),
        _has_ddcs(not args.has_key("skip_ddc") and not device->find_blocks(DDC_BLOCK_NAME).empty()),
        _has_dmafifo(not args.has_key("skip_dram") and not device->find_blocks(DFIFO_BLOCK_NAME).empty()),
        _num_mboards(_tree->list("/mboards").size()),
        _num_radios_per_board(device->find_blocks<radio_ctrl>("0/Radio").size()), // These might throw, maybe we catch that and provide a nicer error message.
        _num_tx_chans_per_radio(
            calc_num_tx_chans_per_radio(_tree, _num_radios_per_board, _has_ducs, not device->find_blocks(DFIFO_BLOCK_NAME).empty())
        ),
        _num_rx_chans_per_radio(_has_ddcs ?
                std::min(num_ports(_tree, RADIO_BLOCK_NAME, "out"), num_ports(_tree, DDC_BLOCK_NAME, "out"))
                : num_ports(_tree, RADIO_BLOCK_NAME, "out")),
        _rx_spp(get_block_ctrl<radio_ctrl>(0, RADIO_BLOCK_NAME, 0)->get_arg<int>("spp")),
        _tx_spp(_rx_spp),
        _rx_channel_map(_num_mboards, std::vector<radio_port_pair_t>(_num_radios_per_board)),
        _tx_channel_map(_num_mboards, std::vector<radio_port_pair_t>(_num_radios_per_board))
    {
        _device->clear();
        check_available_periphs(); // Throws if invalid configuration.
        setup_prop_tree();
        if (_tree->exists("/mboards/0/mtu/send")) {
            _tx_spp = (_tree->access<size_t>("/mboards/0/mtu/send").get() - MAX_BYTES_PER_HEADER) / BYTES_PER_SAMPLE;
        }
        connect_blocks();
        if (args.has_key("skip_ddc")) {
            UHD_LEGACY_LOG() << "[legacy_compat] Skipping DDCs by user request." << std::endl;
        } else if (not _has_ddcs) {
            UHD_MSG(warning)
                << "[legacy_compat] No DDCs detected. You will only be able to receive at the radio frontend rate."
                << std::endl;
        }
        if (args.has_key("skip_duc")) {
            UHD_LEGACY_LOG() << "[legacy_compat] Skipping DUCs by user request." << std::endl;
        } else if (not _has_ducs) {
            UHD_MSG(warning) << "[legacy_compat] No DUCs detected. You will only be able to transmit at the radio frontend rate." << std::endl;
        }
        if (args.has_key("skip_dram")) {
            UHD_LEGACY_LOG() << "[legacy_compat] Skipping DRAM by user request." << std::endl;
        } else if (not _has_dmafifo) {
            UHD_MSG(warning) << "[legacy_compat] No DMA FIFO detected. You will only be able to transmit at slow rates." << std::endl;
        }

        for (size_t mboard = 0; mboard < _num_mboards; mboard++) {
            for (size_t radio = 0; radio < _num_radios_per_board; radio++) {
                _rx_channel_map[mboard][radio].radio_index = radio;
                _tx_channel_map[mboard][radio].radio_index = radio;
            }

            const double tick_rate = _tree->access<double>(mb_root(mboard) / "tick_rate").get();
            update_tick_rate_on_blocks(tick_rate, mboard);
        }
    }

    /************************************************************************
     * API Calls
     ***********************************************************************/
    uhd::fs_path rx_dsp_root(const size_t mboard_idx, const size_t chan)
    {
        // The DSP index is the same as the radio index
        size_t dsp_index = _rx_channel_map[mboard_idx][chan].radio_index;
        size_t port_index = _rx_channel_map[mboard_idx][chan].port_index;

        if (not _has_ddcs) {
            return mb_root(mboard_idx) / "rx_dsps" / dsp_index / port_index;
        }

        return mb_root(mboard_idx) / "xbar" /
               str(boost::format("%s_%d") % DDC_BLOCK_NAME % dsp_index) /
               "legacy_api" / port_index;
    }

    uhd::fs_path tx_dsp_root(const size_t mboard_idx, const size_t chan)
    {
        // The DSP index is the same as the radio index
        size_t dsp_index = _tx_channel_map[mboard_idx][chan].radio_index;
        size_t port_index = _tx_channel_map[mboard_idx][chan].port_index;

        if (not _has_ducs) {
            return mb_root(mboard_idx) / "tx_dsps" / dsp_index / port_index;
        }

        return mb_root(mboard_idx) / "xbar" /
               str(boost::format("%s_%d") % DUC_BLOCK_NAME % dsp_index) /
               "legacy_api" / port_index;
    }

    uhd::fs_path rx_fe_root(const size_t mboard_idx, const size_t chan)
    {
        size_t radio_index = _rx_channel_map[mboard_idx][chan].radio_index;
        size_t port_index = _rx_channel_map[mboard_idx][chan].port_index;
        return uhd::fs_path(str(
                boost::format("/mboards/%d/xbar/%s_%d/rx_fe_corrections/%d/")
                % mboard_idx % RADIO_BLOCK_NAME % radio_index % port_index
        ));
    }

    uhd::fs_path tx_fe_root(const size_t mboard_idx, const size_t chan)
    {
        size_t radio_index = _tx_channel_map[mboard_idx][chan].radio_index;
        size_t port_index = _tx_channel_map[mboard_idx][chan].port_index;
        return uhd::fs_path(str(
                boost::format("/mboards/%d/xbar/%s_%d/tx_fe_corrections/%d/")
                % mboard_idx % RADIO_BLOCK_NAME % radio_index % port_index
        ));
    }

    void issue_stream_cmd(const stream_cmd_t &stream_cmd, size_t mboard, size_t chan)
    {
        UHD_LEGACY_LOG() << "[legacy_compat] issue_stream_cmd() " << std::endl;
        const size_t &radio_index = _rx_channel_map[mboard][chan].radio_index;
        const size_t &port_index  = _rx_channel_map[mboard][chan].port_index;
        if (_has_ddcs) {
            get_block_ctrl<ddc_block_ctrl>(mboard, DDC_BLOCK_NAME, radio_index)->issue_stream_cmd(stream_cmd, port_index);
        } else {
            get_block_ctrl<radio_ctrl>(mboard, RADIO_BLOCK_NAME, radio_index)->issue_stream_cmd(stream_cmd, port_index);
        }
    }

    //! Sets block_id<N> and block_port<N> in the streamer args, otherwise forwards the call
    uhd::rx_streamer::sptr get_rx_stream(const uhd::stream_args_t &args_)
    {
        uhd::stream_args_t args(args_);
        if (args.otw_format.empty()) {
            args.otw_format = "sc16";
        }
        _update_stream_args_for_streaming<uhd::RX_DIRECTION>(args, _rx_channel_map);
        UHD_LEGACY_LOG() << "[legacy_compat] rx stream args: " << args.args.to_string() << std::endl;
        return _device->get_rx_stream(args);
    }

    //! Sets block_id<N> and block_port<N> in the streamer args, otherwise forwards the call.
    // If spp is in the args, update the radios. If it's not set, copy the value from the radios.
    uhd::tx_streamer::sptr get_tx_stream(const uhd::stream_args_t &args_)
    {
        uhd::stream_args_t args(args_);
        if (args.otw_format.empty()) {
            args.otw_format = "sc16";
        }
        _update_stream_args_for_streaming<uhd::TX_DIRECTION>(args, _tx_channel_map);
        UHD_LEGACY_LOG() << "[legacy_compat] tx stream args: " << args.args.to_string() << std::endl;
        return _device->get_tx_stream(args);
    }

    double get_tick_rate(const size_t mboard_idx=0)
    {
        return _tree->access<double>(mb_root(mboard_idx) / "tick_rate").get();
    }

    uhd::meta_range_t lambda_get_samp_rate_range(
            const size_t mboard_idx,
            const size_t radio_idx,
            const size_t chan,
            uhd::direction_t dir
    ) {
        radio_ctrl::sptr radio_sptr = get_block_ctrl<radio_ctrl>(mboard_idx, RADIO_BLOCK_NAME, radio_idx);
        const double samp_rate = (dir == uhd::TX_DIRECTION) ?
            radio_sptr->get_input_samp_rate(chan) :
            radio_sptr->get_output_samp_rate(chan)
        ;

        return uhd::meta_range_t(samp_rate, samp_rate, 0.0);
    }

    void set_tick_rate(const double tick_rate, const size_t mboard_idx=0)
    {
        _tree->access<double>(mb_root(mboard_idx) / "tick_rate").set(tick_rate);
        update_tick_rate_on_blocks(tick_rate, mboard_idx);
    }

private: // types
    struct radio_port_pair_t {
        radio_port_pair_t(const size_t radio=0, const size_t port=0) : radio_index(radio), port_index(port) {}
        size_t radio_index;
        size_t port_index;
    };
    //! Map: _rx_channel_map[mboard_idx][chan_idx] => (Radio, Port)
    // Container is not a std::map because we need to guarantee contiguous
    // ports and correct order anyway.
    typedef std::vector< std::vector<radio_port_pair_t> > chan_map_t;

private: // methods
    /************************************************************************
     * Private helpers
     ***********************************************************************/
    std::string get_slot_name(const size_t radio_index)
    {
        return (radio_index == 0) ? "A" : "B";
    }

    size_t get_radio_index(const std::string slot_name)
    {
        return (slot_name == "A") ? 0 : 1;
    }

    template <typename block_type>
    inline typename block_type::sptr get_block_ctrl(const size_t mboard_idx, const std::string &name, const size_t block_count)
    {
        block_id_t block_id(mboard_idx, name, block_count);
        return _device->get_block_ctrl<block_type>(block_id);
    }

    template <uhd::direction_t dir>
    void _update_stream_args_for_streaming(
            uhd::stream_args_t &args,
            chan_map_t &chan_map
    ) {
        // If the user provides spp, that value is always applied. If it's
        // different from what we thought it was, we need to update the blocks.
        // If it's not provided, we provide our own spp value.
        const size_t args_spp = args.args.cast<size_t>("spp", 0);
        if (dir == uhd::RX_DIRECTION) {
            if (args.args.has_key("spp") and args_spp != _rx_spp) {
                for (size_t mboard = 0; mboard < _num_mboards; mboard++) {
                    for (size_t radio = 0; radio < _num_radios_per_board; radio++) {
                        get_block_ctrl<radio_ctrl>(mboard, RADIO_BLOCK_NAME, radio)->set_arg<int>("spp", args_spp);
                    }
                }
                _rx_spp = args_spp;
                // TODO: Update flow control on the blocks
            } else {
                args.args["spp"] = str(boost::format("%d") % _rx_spp);
            }
        } else {
            if (args.args.has_key("spp") and args_spp != _tx_spp) {
                _tx_spp = args_spp;
                // TODO: Update flow control on the blocks
            } else {
                args.args["spp"] = str(boost::format("%d") % _tx_spp);
            }
        }

        if (args.channels.empty()) {
            args.channels = std::vector<size_t>(1, 0);
        }
        for (size_t i = 0; i < args.channels.size(); i++) {
            const size_t stream_arg_chan_idx = args.channels[i];
            // Determine which mboard, and on that mboard, which channel this is:
            size_t mboard_idx = 0;
            size_t this_mboard_chan_idx = stream_arg_chan_idx;
            while (this_mboard_chan_idx >= chan_map[mboard_idx].size()) {
                mboard_idx++;
                this_mboard_chan_idx -= chan_map[mboard_idx].size();
            }
            if (mboard_idx >= chan_map.size()) {
                throw uhd::index_error(str(
                    boost::format("[legacy_compat]: %s channel %u out of range for given frontend configuration.")
                    % (dir == uhd::TX_DIRECTION ? "TX" : "RX")
                    % stream_arg_chan_idx
                ));
            }
            // Map that mboard and channel to a block:
            const size_t radio_index = chan_map[mboard_idx][this_mboard_chan_idx].radio_index;
            size_t port_index = chan_map[mboard_idx][this_mboard_chan_idx].port_index;
            const std::string block_name = _get_streamer_block_id_and_port<dir>(mboard_idx, radio_index, port_index);
            args.args[str(boost::format("block_id%d") % stream_arg_chan_idx)] = block_name;
            args.args[str(boost::format("block_port%d") % stream_arg_chan_idx)] = str(boost::format("%d") % port_index);
        }
    }

    template <uhd::direction_t dir>
    std::string _get_streamer_block_id_and_port(
            const size_t mboard_idx,
            const size_t radio_index,
            size_t &port_index
    ) {
        if (dir == uhd::TX_DIRECTION) {
            if (_has_dmafifo) {
                port_index = radio_index;
                return block_id_t(mboard_idx, DFIFO_BLOCK_NAME, 0).to_string();
            } else {
                if (_has_ducs) {
                    return block_id_t(mboard_idx, DUC_BLOCK_NAME, radio_index).to_string();
                } else {
                    return block_id_t(mboard_idx, RADIO_BLOCK_NAME, radio_index).to_string();
                }
            }
        } else {
            if (_has_ddcs) {
                return block_id_t(mboard_idx, DDC_BLOCK_NAME, radio_index).to_string();
            } else {
                return block_id_t(mboard_idx, RADIO_BLOCK_NAME, radio_index).to_string();
            }
        }
    }

    /************************************************************************
     * Initialization
     ***********************************************************************/
    /*! Check this device has all the required peripherals.
     *
     * Check rules:
     * - Every mboard needs the same number of radios.
     * - For every radio block, there must be DDC and a DUC block,
     *   with matching number of ports.
     *
     * \throw uhd::runtime_error if any of these checks fail.
     */
    void check_available_periphs()
    {
        if (_num_radios_per_board == 0) {
            throw uhd::runtime_error("For legacy APIs, all devices require at least one radio.");
        }
        block_id_t radio_block_id(0, RADIO_BLOCK_NAME);
        block_id_t duc_block_id(0, DUC_BLOCK_NAME);
        block_id_t ddc_block_id(0, DDC_BLOCK_NAME);
        block_id_t fifo_block_id(0, DFIFO_BLOCK_NAME, 0);
        for (size_t i = 0; i < _num_mboards; i++) {
            radio_block_id.set_device_no(i);
            duc_block_id.set_device_no(i);
            ddc_block_id.set_device_no(i);
            fifo_block_id.set_device_no(i);
            for (size_t k = 0; k < _num_radios_per_board; k++) {
                radio_block_id.set_block_count(k);
                duc_block_id.set_block_count(k);
                ddc_block_id.set_block_count(k);
                // Only one FIFO per crossbar, so don't set block count for that block
                if (not _device->has_block(radio_block_id)
                    or (_has_ducs and not _device->has_block(duc_block_id))
                    or (_has_ddcs and not _device->has_block(ddc_block_id))
                    or (_has_dmafifo and not _device->has_block(fifo_block_id))
                ) {
                    throw uhd::runtime_error("For legacy APIs, all devices require the same number of radios, DDCs and DUCs.");
                }

                const size_t this_spp = get_block_ctrl<radio_ctrl>(i, RADIO_BLOCK_NAME, k)->get_arg<int>("spp");
                if (this_spp != _rx_spp) {
                    throw uhd::runtime_error(str(
                            boost::format("[legacy compat] Radios have differing spp values: %s has %d, others have %d")
                            % radio_block_id.to_string() % this_spp % _rx_spp
                    ));
                }
            }
        }
    }

    /*! Initialize properties in property tree to match legacy mode
     */
    void setup_prop_tree()
    {
        for (size_t mboard_idx = 0; mboard_idx < _num_mboards; mboard_idx++) {
            uhd::fs_path root = mb_root(mboard_idx);
            // Subdev specs
            if (_tree->exists(root / "tx_subdev_spec")) {
                _tree->access<subdev_spec_t>(root / "tx_subdev_spec")
                    .add_coerced_subscriber(boost::bind(&legacy_compat_impl::set_subdev_spec, this, _1, mboard_idx, uhd::TX_DIRECTION))
                    .update()
                    .set_publisher(boost::bind(&legacy_compat_impl::get_subdev_spec, this, mboard_idx, uhd::TX_DIRECTION));
            } else {
                _tree->create<subdev_spec_t>(root / "tx_subdev_spec")
                    .add_coerced_subscriber(boost::bind(&legacy_compat_impl::set_subdev_spec, this, _1, mboard_idx, uhd::TX_DIRECTION))
                    .set_publisher(boost::bind(&legacy_compat_impl::get_subdev_spec, this, mboard_idx, uhd::TX_DIRECTION));
            }

            if (_tree->exists(root / "rx_subdev_spec")) {
                _tree->access<subdev_spec_t>(root / "rx_subdev_spec")
                    .add_coerced_subscriber(boost::bind(&legacy_compat_impl::set_subdev_spec, this, _1, mboard_idx, uhd::RX_DIRECTION))
                    .update()
                    .set_publisher(boost::bind(&legacy_compat_impl::get_subdev_spec, this, mboard_idx, uhd::RX_DIRECTION));
            } else {
                 _tree->create<subdev_spec_t>(root / "rx_subdev_spec")
                    .add_coerced_subscriber(boost::bind(&legacy_compat_impl::set_subdev_spec, this, _1, mboard_idx, uhd::RX_DIRECTION))
                    .set_publisher(boost::bind(&legacy_compat_impl::get_subdev_spec, this, mboard_idx, uhd::RX_DIRECTION));
            }

            if (not _has_ddcs) {
                for (size_t radio_idx = 0; radio_idx < _num_radios_per_board; radio_idx++) {
                    for (size_t chan = 0; chan < _num_rx_chans_per_radio; chan++) {
                        const uhd::fs_path rx_dsp_base_path(mb_root(mboard_idx) / "rx_dsps" / radio_idx / chan);
                        _tree->create<double>(rx_dsp_base_path / "rate/value")
                            .set(0.0)
                            .set_publisher(
                                boost::bind(
                                    &radio_ctrl::get_output_samp_rate,
                                    get_block_ctrl<radio_ctrl>(mboard_idx, RADIO_BLOCK_NAME, radio_idx),
                                    chan
                                )
                            )
                        ;
                        _tree->create<uhd::meta_range_t>(rx_dsp_base_path / "rate/range")
                            .set_publisher(
                                boost::bind(
                                    &legacy_compat_impl::lambda_get_samp_rate_range,
                                    this,
                                    mboard_idx, radio_idx, chan,
                                    uhd::RX_DIRECTION
                                )
                            )
                        ;
                        _tree->create<double>(rx_dsp_base_path / "freq/value")
                            .set_publisher(boost::bind(&lambda_const_double, 0.0))
                        ;
                        _tree->create<uhd::meta_range_t>(rx_dsp_base_path / "freq/range")
                            .set_publisher(boost::bind(&lambda_const_meta_range, 0.0, 0.0, 0.0))
                        ;
                    }
                }
            }
            if (not _has_ducs) {
                for (size_t radio_idx = 0; radio_idx < _num_radios_per_board; radio_idx++) {
                    for (size_t chan = 0; chan < _num_tx_chans_per_radio; chan++) {
                        const uhd::fs_path tx_dsp_base_path(mb_root(mboard_idx) / "tx_dsps" / radio_idx / chan);
                        _tree->create<double>(tx_dsp_base_path / "rate/value")
                            .set(0.0)
                            .set_publisher(
                                boost::bind(
                                    &radio_ctrl::get_output_samp_rate,
                                    get_block_ctrl<radio_ctrl>(mboard_idx, RADIO_BLOCK_NAME, radio_idx),
                                    chan
                                )
                            )
                        ;
                        _tree->create<uhd::meta_range_t>(tx_dsp_base_path / "rate/range")
                            .set_publisher(
                                boost::bind(
                                    &legacy_compat_impl::lambda_get_samp_rate_range,
                                    this,
                                    mboard_idx, radio_idx, chan,
                                    uhd::TX_DIRECTION
                                )
                            )
                        ;
                        _tree->create<double>(tx_dsp_base_path / "freq/value")
                            .set_publisher(boost::bind(&lambda_const_double, 0.0))
                        ;
                        _tree->create<uhd::meta_range_t>(tx_dsp_base_path / "freq/range")
                            .set_publisher(boost::bind(&lambda_const_meta_range, 0.0, 0.0, 0.0))
                        ;
                    }
                }
            }
        }
    }

    /*! Default block connections.
     *
     * Tx connections:
     *
     * [Host] => DMA FIFO => DUC => Radio
     *
     * Note: There is only one DMA FIFO per crossbar, with twice the number of ports.
     *
     * Rx connections:
     *
     * Radio => DDC => [Host]
     *
     * Streamers are *not* generated here.
     */
    void connect_blocks()
    {
        _graph = _device->create_graph("legacy");
        const size_t rx_bpp = _rx_spp * BYTES_PER_SAMPLE + MAX_BYTES_PER_HEADER;
        const size_t tx_bpp = _tx_spp * BYTES_PER_SAMPLE + MAX_BYTES_PER_HEADER;
        for (size_t mboard = 0; mboard < _num_mboards; mboard++) {
            for (size_t radio = 0; radio < _num_radios_per_board; radio++) {
                // Tx Channels
                for (size_t chan = 0; chan < _num_tx_chans_per_radio; chan++) {
                    if (_has_ducs) {
                        _graph->connect(
                            block_id_t(mboard, DUC_BLOCK_NAME,   radio), chan,
                            block_id_t(mboard, RADIO_BLOCK_NAME, radio), chan,
                            tx_bpp
                        );
                        if (_has_dmafifo) {
                            // We have DMA FIFO *and* DUCs
                            _graph->connect(
                                block_id_t(mboard, DFIFO_BLOCK_NAME, 0), radio,
                                block_id_t(mboard, DUC_BLOCK_NAME, radio), chan,
                                tx_bpp
                            );
                        }
                    } else if (_has_dmafifo) {
                            // We have DMA FIFO, *no* DUCs
                            _graph->connect(
                                block_id_t(mboard, DFIFO_BLOCK_NAME,   0), radio,
                                block_id_t(mboard, RADIO_BLOCK_NAME, radio), chan,
                                tx_bpp
                            );
                    }
                }
                // Rx Channels
                for (size_t chan = 0; chan < _num_rx_chans_per_radio; chan++) {
                    if (_has_ddcs) {
                        _graph->connect(
                            block_id_t(mboard, RADIO_BLOCK_NAME, radio), chan,
                            block_id_t(mboard, DDC_BLOCK_NAME,   radio), chan,
                            rx_bpp
                        );
                    }
                }
            }
        }
    }


    /************************************************************************
     * Subdev translation
     ***********************************************************************/
    /*! Subdev -> (Radio, Port)
     *
     * Example: Device is X300, subdev spec is 'A:0 B:0', we have 2 radios.
     * Then we map to ((0, 0), (1, 0)). I.e., zero-th port on radio 0 and
     * radio 1, respectively.
     */
    void set_subdev_spec(const subdev_spec_t &spec, const size_t mboard, const uhd::direction_t dir)
    {
        UHD_ASSERT_THROW(mboard < _num_mboards);
        chan_map_t &chan_map = (dir == uhd::TX_DIRECTION) ? _tx_channel_map : _rx_channel_map;
        std::vector<radio_port_pair_t> new_mapping(spec.size());
        for (size_t i = 0; i < spec.size(); i++) {
            const size_t new_radio_index = get_radio_index(spec[i].db_name);
            radio_ctrl::sptr radio = get_block_ctrl<radio_ctrl>(mboard, "Radio", new_radio_index);
            size_t new_port_index = radio->get_chan_from_dboard_fe(spec[i].sd_name, dir);
            if (new_port_index >= radio->get_input_ports().size()) {
                new_port_index = radio->get_input_ports().at(0);
            }
            radio_port_pair_t new_radio_port_pair(new_radio_index, new_port_index);
            new_mapping[i] = new_radio_port_pair;
        }
        chan_map[mboard] = new_mapping;
    }

    subdev_spec_t get_subdev_spec(const size_t mboard, const uhd::direction_t dir)
    {
        UHD_ASSERT_THROW(mboard < _num_mboards);
        subdev_spec_t subdev_spec;
        chan_map_t &chan_map = (dir == uhd::TX_DIRECTION) ? _tx_channel_map : _rx_channel_map;
        for (size_t chan_idx = 0; chan_idx < chan_map[mboard].size(); chan_idx++) {
            const size_t radio_index = chan_map[mboard][chan_idx].radio_index;
            const size_t port_index = chan_map[mboard][chan_idx].port_index;
            const std::string new_db_name = get_slot_name(radio_index);
            const std::string new_sd_name =
                get_block_ctrl<radio_ctrl>(mboard, "Radio", radio_index)->get_dboard_fe_from_chan(port_index, dir);
            subdev_spec_pair_t new_pair(new_db_name, new_sd_name);
            subdev_spec.push_back(new_pair);
        }

        return subdev_spec;
    }

    void update_tick_rate_on_blocks(const double tick_rate, const size_t mboard_idx)
    {
        block_id_t radio_block_id(mboard_idx, RADIO_BLOCK_NAME);
        block_id_t duc_block_id(mboard_idx, DUC_BLOCK_NAME);
        block_id_t ddc_block_id(mboard_idx, DDC_BLOCK_NAME);

        for (size_t radio = 0; radio < _num_radios_per_board; radio++) {
            radio_block_id.set_block_count(radio);
            duc_block_id.set_block_count(radio);
            ddc_block_id.set_block_count(radio);
            radio_ctrl::sptr radio_sptr = _device->get_block_ctrl<radio_ctrl>(radio_block_id);
            radio_sptr->set_rate(tick_rate);
            for (size_t chan = 0; chan < _num_rx_chans_per_radio and _has_ddcs; chan++) {
                const double radio_output_rate = radio_sptr->get_output_samp_rate(chan);
                _device->get_block_ctrl(ddc_block_id)->set_arg<double>("input_rate", radio_output_rate, chan);
            }
            for (size_t chan = 0; chan < _num_tx_chans_per_radio and _has_ducs; chan++) {
                const double radio_input_rate = radio_sptr->get_input_samp_rate(chan);
                _device->get_block_ctrl(duc_block_id)->set_arg<double>("output_rate", radio_input_rate, chan);
            }
        }
    }

private: // attributes
    uhd::device3::sptr _device;
    uhd::property_tree::sptr _tree;

    const bool _has_ducs;
    const bool _has_ddcs;
    const bool _has_dmafifo;
    const size_t _num_mboards;
    const size_t _num_radios_per_board;
    const size_t _num_tx_chans_per_radio;
    const size_t _num_rx_chans_per_radio;
    size_t _rx_spp;
    size_t _tx_spp;

    chan_map_t _rx_channel_map;
    chan_map_t _tx_channel_map;

    graph::sptr _graph;
};

legacy_compat::sptr legacy_compat::make(
        uhd::device3::sptr device,
        const uhd::device_addr_t &args
) {
    UHD_ASSERT_THROW(bool(device));
    static std::map<void *, boost::weak_ptr<legacy_compat> > legacy_cache;

    if (legacy_cache.count(device.get())) {
        legacy_compat::sptr legacy_compat_copy = legacy_cache.at(device.get()).lock();
        if (not bool(legacy_compat_copy)) {
            throw uhd::runtime_error("Reference to existing legacy compat object expired prematurely!");
        }

        UHD_LEGACY_LOG() << "[legacy_compat] Using existing legacy compat object for this device." << std::endl;
        return legacy_compat_copy;
    }

    legacy_compat::sptr new_legacy_compat = boost::make_shared<legacy_compat_impl>(device, args);
    legacy_cache[device.get()] = new_legacy_compat;
    return new_legacy_compat;
}