1 files changed, 130 insertions, 0 deletions
diff --git a/host/lib/include/uhdlib/rfnoc/rx_flow_ctrl_state.hpp b/host/lib/include/uhdlib/rfnoc/rx_flow_ctrl_state.hpp
new file mode 100644
index 000000000..937baf982
--- /dev/null
+++ b/host/lib/include/uhdlib/rfnoc/rx_flow_ctrl_state.hpp
@@ -0,0 +1,130 @@
+//
+// Copyright 2019 Ettus Research, a National Instruments Brand
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+#ifndef INCLUDED_LIBUHD_RFNOC_RX_FLOW_CTRL_STATE_HPP
+#define INCLUDED_LIBUHD_RFNOC_RX_FLOW_CTRL_STATE_HPP
+
+#include <uhd/utils/log.hpp>
+#include <uhdlib/rfnoc/rfnoc_common.hpp>
+
+namespace uhd { namespace rfnoc {
+
+//! Class to manage rx flow control state
+class rx_flow_ctrl_state
+{
+public:
+    //! Constructor
+    rx_flow_ctrl_state(const rfnoc::sep_id_pair_t epids) : _epids(epids) {}
+
+    //! Initialize frequency parameters
+    void initialize(const stream_buff_params_t fc_freq)
+    {
+        _fc_freq = fc_freq;
+    }
+
+    //! Resynchronize with transfer counts from the sender
+    void resynchronize(const stream_buff_params_t counts)
+    {
+        if (_recv_counts.bytes != counts.bytes
+            || _recv_counts.packets != counts.packets) {
+            // If there is a discrepancy between the amount of data sent by
+            // the device and received by the transport, adjust the counts
+            // of data received and transferred to include the dropped data.
+            auto bytes_dropped = counts.bytes - _recv_counts.bytes;
+            auto pkts_dropped  = counts.packets - _recv_counts.packets;
+            _xfer_counts.bytes += bytes_dropped;
+            _xfer_counts.packets += pkts_dropped;
+
+            UHD_LOGGER_DEBUG("rx_flow_ctrl_state")
+                << "oh noes: bytes_sent=" << counts.bytes
+                << "  bytes_received=" << _recv_counts.bytes
+                << "  pkts_sent=" << counts.packets
+                << "  pkts_received=" << _recv_counts.packets
+                << " src_epid=" << _epids.first << " dst_epid=" << _epids.second
+                << std::endl;
+
+            _recv_counts = counts;
+        }
+    }
+
+    //! Reset the transfer counts (happens during init)
+    void reset_counts()
+    {
+        UHD_LOGGER_TRACE("rx_flow_ctrl_state")
+            << "Resetting transfer counts" << std::endl;
+        _recv_counts = {0, 0};
+        _xfer_counts = {0, 0};
+    }
+
+    //! Update state when data is received
+    void data_received(const size_t bytes)
+    {
+        _recv_counts.bytes += bytes;
+        _recv_counts.packets++;
+    }
+
+    //! Update state when transfer is complete (buffer space freed)
+    void xfer_done(const size_t bytes)
+    {
+        _xfer_counts.bytes += bytes;
+        _xfer_counts.packets++;
+    }
+
+    //! Returns whether a flow control response is needed
+    bool fc_resp_due() const
+    {
+        stream_buff_params_t accum_counts = {
+            _xfer_counts.bytes - _last_fc_resp_counts.bytes,
+            _xfer_counts.packets - _last_fc_resp_counts.packets};
+
+        return accum_counts.bytes >= _fc_freq.bytes
+               || accum_counts.packets >= _fc_freq.packets;
+    }
+
+    //! Update state after flow control response was sent
+    void fc_resp_sent()
+    {
+        _last_fc_resp_counts = _xfer_counts;
+    }
+
+    //! Returns counts for completed transfers
+    stream_buff_params_t get_xfer_counts() const
+    {
+        return _xfer_counts;
+    }
+
+    //! Returns counts for completed transfers
+    stream_buff_params_t get_recv_counts() const
+    {
+        return _recv_counts;
+    }
+
+    //! Returns configured flow control frequency
+    stream_buff_params_t get_fc_freq() const
+    {
+        return _fc_freq;
+    }
+
+private:
+    // Counts for data received, including any data still in use
+    stream_buff_params_t _recv_counts{0, 0};
+
+    // Counts for data read and whose buffer space is ok to reuse
+    stream_buff_params_t _xfer_counts{0, 0};
+
+    // Counts sent in last flow control response
+    stream_buff_params_t _last_fc_resp_counts{0, 0};
+
+    // Frequency of flow control responses
+    stream_buff_params_t _fc_freq{0, 0};
+
+    // Endpoint ID for log messages
+    const sep_id_pair_t _epids;
+};
+
+}} // namespace uhd::rfnoc
+
+#endif /* INCLUDED_LIBUHD_RFNOC_RX_FLOW_CTRL_STATE_HPP */