dsp rework: work on scaling and args parsing on RX and TX dsp

This simplified some copy pasta in the io_impl.cpp files,
and adds a place for sc8 tx mode in the tx dsp core code.

4 files changed, 48 insertions, 11 deletions

diff --git a/host/lib/usrp/cores/rx_dsp_core_200.cpp b/host/lib/usrp/cores/rx_dsp_core_200.cpp
index cbc732c9c..b2bf934bc 100644
--- a/host/lib/usrp/cores/rx_dsp_core_200.cpp
+++ b/host/lib/usrp/cores/rx_dsp_core_200.cpp
@@ -224,17 +224,19 @@ public:
         if (_continuous_streaming) issue_stream_command(stream_cmd_t::STREAM_MODE_START_CONTINUOUS);
     }
 
-    void set_format(const std::string &format, const unsigned scale){
+    void setup(const uhd::stream_args_t &stream_args){
+        if (not stream_args.args.has_key("noclear")) this->clear();
+
         unsigned format_word = 0;
-        if (format == "sc16"){
+        if (stream_args.otw_format == "sc16"){
             format_word = 0;
             _extra_scaling = 1.0;
         }
-        else if (format == "sc8"){
+        else if (stream_args.otw_format == "sc8"){
             format_word = (1 << 0);
-            _extra_scaling = scale;
+            _extra_scaling = stream_args.args.cast<double>("scalar", 1.0);
         }
-        else throw uhd::value_error("USRP RX cannot handle requested wire format: " + format);
+        else throw uhd::value_error("USRP RX cannot handle requested wire format: " + stream_args.otw_format);
 
         this->update_scalar();
 
diff --git a/host/lib/usrp/cores/rx_dsp_core_200.hpp b/host/lib/usrp/cores/rx_dsp_core_200.hpp
index 58be51eee..b01f751e9 100644
--- a/host/lib/usrp/cores/rx_dsp_core_200.hpp
+++ b/host/lib/usrp/cores/rx_dsp_core_200.hpp
@@ -19,6 +19,7 @@
 #define INCLUDED_LIBUHD_USRP_RX_DSP_CORE_200_HPP
 
 #include <uhd/config.hpp>
+#include <uhd/stream.hpp>
 #include <uhd/types/ranges.hpp>
 #include <boost/utility.hpp>
 #include <boost/shared_ptr.hpp>
@@ -60,7 +61,7 @@ public:
 
     virtual void handle_overflow(void) = 0;
 
-    virtual void set_format(const std::string &format, const unsigned scale) = 0;
+    virtual void setup(const uhd::stream_args_t &stream_args) = 0;
 };
 
 #endif /* INCLUDED_LIBUHD_USRP_RX_DSP_CORE_200_HPP */
diff --git a/host/lib/usrp/cores/tx_dsp_core_200.cpp b/host/lib/usrp/cores/tx_dsp_core_200.cpp
index f4c303d05..2c5b86bfc 100644
--- a/host/lib/usrp/cores/tx_dsp_core_200.cpp
+++ b/host/lib/usrp/cores/tx_dsp_core_200.cpp
@@ -58,6 +58,11 @@ public:
     ):
         _iface(iface), _dsp_base(dsp_base), _ctrl_base(ctrl_base), _sid(sid)
     {
+        //init to something so update method has reasonable defaults
+        _scaling_adjustment = 1.0;
+        _extra_scaling = 1.0;
+        _fxpt_scalar_correction = 1.0;
+
         //init the tx control registers
         this->clear();
         this->set_underflow_policy("next_packet");
@@ -121,13 +126,24 @@ public:
 
         // Calculate CIC interpolation (i.e., without halfband interpolators)
         // Calculate closest multiplier constant to reverse gain absent scale multipliers
-        double rate_cubed = std::pow(double(interp & 0xff), 3);
-        const boost::int32_t scale = boost::math::iround((4096*std::pow(2, ceil_log2(rate_cubed)))/(1.65*rate_cubed));
-        _iface->poke32(REG_DSP_TX_SCALE_IQ, scale);
+        const double rate_pow = std::pow(double(interp & 0xff), 3);
+        _scaling_adjustment = std::pow(2, ceil_log2(rate_pow))/(1.65*rate_pow);
+        this->update_scalar();
 
         return _tick_rate/interp_rate;
     }
 
+    void update_scalar(void){
+        const double target_scalar = (1 << 17)*_scaling_adjustment/_extra_scaling;
+        const boost::int32_t actual_scalar = boost::math::iround(target_scalar);
+        _fxpt_scalar_correction = target_scalar/actual_scalar; //should be small
+        _iface->poke32(REG_DSP_TX_SCALE_IQ, actual_scalar);
+    }
+
+    double get_scaling_adjustment(void){
+        return _fxpt_scalar_correction*_extra_scaling*32767.;
+    }
+
     double set_freq(const double freq_){
         //correct for outside of rate (wrap around)
         double freq = std::fmod(freq_, _tick_rate);
@@ -156,10 +172,26 @@ public:
         _iface->poke32(REG_TX_CTRL_PACKETS_PER_UP, (packets_per_up == 0)? 0 : (FLAG_TX_CTRL_UP_ENB | packets_per_up));
     }
 
+    void setup(const uhd::stream_args_t &stream_args){
+        if (not stream_args.args.has_key("noclear")) this->clear();
+
+        if (stream_args.otw_format == "sc16"){
+            _extra_scaling = 1.0;
+        }
+        else throw uhd::value_error("USRP TX cannot handle requested wire format: " + stream_args.otw_format);
+
+        this->update_scalar();
+
+        if (stream_args.args.has_key("underflow_policy")){
+            this->set_underflow_policy(stream_args.args["underflow_policy"]);
+        }
+    }
+
 private:
     wb_iface::sptr _iface;
     const size_t _dsp_base, _ctrl_base;
     double _tick_rate, _link_rate;
+    double _scaling_adjustment, _extra_scaling, _fxpt_scalar_correction;
     const boost::uint32_t _sid;
 };
 
diff --git a/host/lib/usrp/cores/tx_dsp_core_200.hpp b/host/lib/usrp/cores/tx_dsp_core_200.hpp
index 4b39a5b07..0e1cfb6bc 100644
--- a/host/lib/usrp/cores/tx_dsp_core_200.hpp
+++ b/host/lib/usrp/cores/tx_dsp_core_200.hpp
@@ -19,6 +19,7 @@
 #define INCLUDED_LIBUHD_USRP_TX_DSP_CORE_200_HPP
 
 #include <uhd/config.hpp>
+#include <uhd/stream.hpp>
 #include <uhd/types/ranges.hpp>
 #include <boost/utility.hpp>
 #include <boost/shared_ptr.hpp>
@@ -44,14 +45,15 @@ public:
 
     virtual uhd::meta_range_t get_host_rates(void) = 0;
 
+    virtual double get_scaling_adjustment(void) = 0;
+
     virtual uhd::meta_range_t get_freq_range(void) = 0;
 
     virtual double set_freq(const double freq) = 0;
 
     virtual void set_updates(const size_t cycles_per_up, const size_t packets_per_up) = 0;
 
-    virtual void set_underflow_policy(const std::string &policy) = 0;
-
+    virtual void setup(const uhd::stream_args_t &stream_args) = 0;
 };
 
 #endif /* INCLUDED_LIBUHD_USRP_TX_DSP_CORE_200_HPP */