3 files changed, 45 insertions, 2 deletions
diff --git a/host/include/uhd/usrp/multi_usrp.hpp b/host/include/uhd/usrp/multi_usrp.hpp
index 27b5f3d9a..4efc062b0 100644
--- a/host/include/uhd/usrp/multi_usrp.hpp
+++ b/host/include/uhd/usrp/multi_usrp.hpp
@@ -614,6 +614,17 @@ public:
      */
     virtual void set_rx_rate(double rate, size_t chan = ALL_CHANS) = 0;
 
+    /*! Set the number of samples sent per packet (spp) for RX streaming
+     *
+     * On RFNoC devices, this will set the spp value on the radio itself. For
+     * older devices, it will inject the spp value into a later get_rx_stream()
+     * call, but it won't change anything in existing streamers.
+     *
+     * \param spp the new spp value
+     * \param chan the channel index 0 to N-1
+     */
+    virtual void set_rx_spp(const size_t spp, const size_t chan = ALL_CHANS) = 0;
+
     /*!
      * Gets the RX sample rate.
      * \param chan the channel index 0 to N-1
diff --git a/host/lib/usrp/multi_usrp.cpp b/host/lib/usrp/multi_usrp.cpp
index 6dad00787..1b39a2827 100644
--- a/host/lib/usrp/multi_usrp.cpp
+++ b/host/lib/usrp/multi_usrp.cpp
@@ -961,7 +961,16 @@ public:
      ******************************************************************/
     rx_streamer::sptr get_rx_stream(const stream_args_t &args) {
         _check_link_rate(args, false);
-        return this->get_device()->get_rx_stream(args);
+        stream_args_t args_ = args;
+        if (!args.args.has_key("spp")) {
+            for (auto chan : args.channels) {
+                if (_rx_spp.count(chan)) {
+                    args_.args.set("spp", std::to_string(_rx_spp.at(chan)));
+                    break;
+                }
+            }
+        }
+        return this->get_device()->get_rx_stream(args_);
     }
 
     void set_rx_subdev_spec(const subdev_spec_t &spec, size_t mboard){
@@ -1018,6 +1027,11 @@ public:
         }
     }
 
+    void set_rx_spp(const size_t spp, const size_t chan = ALL_CHANS)
+    {
+        _rx_spp[chan] = spp;
+    }
+
     double get_rx_rate(size_t chan){
         return _tree->access<double>(rx_dsp_root(chan) / "rate" / "value").get();
     }
@@ -2258,6 +2272,9 @@ private:
     device::sptr _dev;
     property_tree::sptr _tree;
 
+    //! Container for spp values set in set_rx_spp()
+    std::unordered_map<size_t, size_t> _rx_spp;
+
     struct mboard_chan_pair{
         size_t mboard, chan;
         mboard_chan_pair(void): mboard(0), chan(0){}
diff --git a/host/lib/usrp/multi_usrp_rfnoc.cpp b/host/lib/usrp/multi_usrp_rfnoc.cpp
index b3851ba9e..d6f16824d 100644
--- a/host/lib/usrp/multi_usrp_rfnoc.cpp
+++ b/host/lib/usrp/multi_usrp_rfnoc.cpp
@@ -16,8 +16,9 @@
 #include <uhd/utils/graph_utils.hpp>
 #include <uhdlib/rfnoc/rfnoc_device.hpp>
 #include <uhdlib/usrp/gpio_defs.hpp>
+#include <uhdlib/utils/narrow.hpp>
 #include <unordered_set>
-#include <boost/pointer_cast.hpp>
+#include <boost/format.hpp>
 #include <algorithm>
 #include <chrono>
 #include <memory>
@@ -1044,6 +1045,20 @@ public:
         _rx_rates[chan] = actual_rate;
     }
 
+    void set_rx_spp(const size_t spp, const size_t chan = ALL_CHANS)
+    {
+        std::lock_guard<std::recursive_mutex> l(_graph_mutex);
+        if (chan == ALL_CHANS) {
+            for (size_t chan = 0; chan < _rx_chans.size(); ++chan) {
+                set_rx_spp(spp, chan);
+            }
+            return;
+        }
+        auto rx_chain = _get_rx_chan(chan);
+        rx_chain.radio->set_property<int>(
+            "spp", narrow_cast<int>(spp), rx_chain.block_chan);
+    }
+
     double get_rx_rate(size_t chan)
     {
         std::lock_guard<std::recursive_mutex> l(_graph_mutex);