From 591aa45a7d20f305f1526f3601c33aa3d3ecb108 Mon Sep 17 00:00:00 2001
From: Martin Braun <martin.braun@ettus.com>
Date: Fri, 28 Feb 2014 18:14:31 +0100
Subject: uhd: multi_usrp now understands link rate info and can check for it

---
 host/include/uhd/usrp/multi_usrp.hpp |  8 ++-----
 host/lib/usrp/multi_usrp.cpp         | 41 ++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/host/include/uhd/usrp/multi_usrp.hpp b/host/include/uhd/usrp/multi_usrp.hpp
index 5b4991202..49aad5d8c 100644
--- a/host/include/uhd/usrp/multi_usrp.hpp
+++ b/host/include/uhd/usrp/multi_usrp.hpp
@@ -119,14 +119,10 @@ public:
     virtual device::sptr get_device(void) = 0;
 
     //! Convenience method to get a RX streamer
-    rx_streamer::sptr get_rx_stream(const stream_args_t &args){
-        return this->get_device()->get_rx_stream(args);
-    }
+    virtual rx_streamer::sptr get_rx_stream(const stream_args_t &args) = 0;
 
     //! Convenience method to get a TX streamer
-    tx_streamer::sptr get_tx_stream(const stream_args_t &args){
-        return this->get_device()->get_tx_stream(args);
-    }
+    virtual tx_streamer::sptr get_tx_stream(const stream_args_t &args) = 0;
 
     /*!
      * Returns identifying information about this USRP's configuration.
diff --git a/host/lib/usrp/multi_usrp.cpp b/host/lib/usrp/multi_usrp.cpp
index f08709669..4883b2410 100644
--- a/host/lib/usrp/multi_usrp.cpp
+++ b/host/lib/usrp/multi_usrp.cpp
@@ -24,6 +24,7 @@
 #include <uhd/usrp/dboard_id.hpp>
 #include <uhd/usrp/mboard_eeprom.hpp>
 #include <uhd/usrp/dboard_eeprom.hpp>
+#include <uhd/convert.hpp>
 #include <boost/assign/list_of.hpp>
 #include <boost/thread.hpp>
 #include <boost/foreach.hpp>
@@ -103,6 +104,8 @@ static meta_range_t make_overall_tune_range(
     return range;
 }
 
+
+
 /***********************************************************************
  * Gain helper functions
  **********************************************************************/
@@ -589,6 +592,11 @@ public:
     /*******************************************************************
      * RX methods
      ******************************************************************/
+    rx_streamer::sptr get_rx_stream(const stream_args_t &args) {
+        _check_link_rate(args, false);
+        return this->get_device()->get_rx_stream(args);
+    }
+
     void set_rx_subdev_spec(const subdev_spec_t &spec, size_t mboard){
         if (mboard != ALL_MBOARDS){
             _tree->access<subdev_spec_t>(mb_root(mboard) / "rx_subdev_spec").set(spec);
@@ -770,6 +778,11 @@ public:
     /*******************************************************************
      * TX methods
      ******************************************************************/
+    tx_streamer::sptr get_tx_stream(const stream_args_t &args) {
+        _check_link_rate(args, true);
+        return this->get_device()->get_tx_stream(args);
+    }
+
     void set_tx_subdev_spec(const subdev_spec_t &spec, size_t mboard){
         if (mboard != ALL_MBOARDS){
             _tree->access<subdev_spec_t>(mb_root(mboard) / "tx_subdev_spec").set(spec);
@@ -1178,6 +1191,34 @@ private:
         }
         return gg;
     }
+
+    //! \param is_tx True for tx
+    // Assumption is that all mboards use the same link
+    bool _check_link_rate(const stream_args_t &args, bool is_tx) {
+        bool link_rate_is_ok = true;
+        size_t bytes_per_sample = convert::get_bytes_per_item(args.otw_format);
+        double max_link_rate = 0;
+        double sum_rate = 0;
+        BOOST_FOREACH(const size_t chan, args.channels) {
+            mboard_chan_pair mcp = is_tx ? tx_chan_to_mcp(chan) : rx_chan_to_mcp(chan);
+            if (_tree->exists(mb_root(mcp.mboard) / "link_max_rate")) {
+                max_link_rate = std::max(
+                    max_link_rate,
+                   _tree->access<double>(mb_root(mcp.mboard) / "link_max_rate").get()
+                );
+            }
+            sum_rate += is_tx ? get_tx_rate(chan) : get_rx_rate(chan);
+        }
+        if (max_link_rate > 0 and (max_link_rate / bytes_per_sample) < sum_rate) {
+            UHD_MSG(warning) << boost::format(
+                "The total sum of rates (%f MSps on %u channels) exceeds the maximum capacity of the connection.\n"
+                "This can cause %s."
+            ) % (sum_rate/1e6) % args.channels.size() % (is_tx ? "underruns (U)" : "overflows (O)")  << std::endl;
+            link_rate_is_ok = false;
+        }
+
+        return link_rate_is_ok;
+    }
 };
 
 /***********************************************************************
-- 
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