hackrf: implement device discovery

Unfortunately libhackrf still doesn't offer a way to enumerate devices
*or* to open a specific device by index or it's serial number. Thus we
have implemented a rather hack-ish way to detect the presence of a
device by trying to open it and closing right after that.

lib/hackrf/hackrf_sink_c.cc

@@ -209,6 +209,7 @@ hackrf_sink_c::hackrf_sink_c (const std::string &args)
               << std::endl;
   }
 
+  set_center_freq( (get_freq_range().start() + get_freq_range().stop()) / 2.0 );
   set_sample_rate( get_sample_rates().start() );
   set_bandwidth( 0 );
 
@@ -449,7 +450,7 @@ std::vector<std::string> hackrf_sink_c::get_devices()
 {
   std::vector<std::string> devices;
   std::string label;
-
+#if 0
   for (unsigned int i = 0; i < 1 /* TODO: missing libhackrf api */; i++) {
     std::string args = "hackrf=" + boost::lexical_cast< std::string >( i );
 
@@ -462,7 +463,49 @@ std::vector<std::string> hackrf_sink_c::get_devices()
     args += ",label='" + label + "'";
     devices.push_back( args );
   }
+#else
+
+  {
+    boost::mutex::scoped_lock lock( _usage_mutex );
+
+    if ( _usage == 0 )
+      hackrf_init(); /* call only once before the first open */
+
+    _usage++;
+  }
+
+  int ret;
+  hackrf_device *dev = NULL;
+  ret = hackrf_open(&dev);
+  if ( HACKRF_SUCCESS == ret )
+  {
+    std::string args = "hackrf=0";
+
+    label = "HackRF";
+
+    uint8_t board_id;
+    ret = hackrf_board_id_read( dev, &board_id );
+    if ( HACKRF_SUCCESS == ret )
+    {
+      label += std::string(" ") + hackrf_board_id_name(hackrf_board_id(board_id));
+    }
+
+    args += ",label='" + label + "'";
+    devices.push_back( args );
+
+    ret = hackrf_close(dev);
+  }
 
+  {
+    boost::mutex::scoped_lock lock( _usage_mutex );
+
+     _usage--;
+
+    if ( _usage == 0 )
+      hackrf_exit(); /* call only once after last close */
+  }
+
+#endif
   return devices;
 }
 

lib/hackrf/hackrf_source_c.cc

@@ -27,8 +27,8 @@
 #include "config.h"
 #endif
 
-#include "hackrf_source_c.h"
-#include <gnuradio/io_signature.h>
+#include <stdexcept>
+#include <iostream>
 
 #include <boost/assign.hpp>
 #include <boost/format.hpp>
@@ -36,8 +36,9 @@
 #include <boost/algorithm/string.hpp>
 #include <boost/thread/thread.hpp>
 
-#include <stdexcept>
-#include <iostream>
+#include <gnuradio/io_signature.h>
+
+#include "hackrf_source_c.h"
 
 #include "arg_helpers.h"
 
@@ -163,6 +164,7 @@ hackrf_source_c::hackrf_source_c (const std::string &args)
               << std::endl;
   }
 
+  set_center_freq( (get_freq_range().start() + get_freq_range().stop()) / 2.0 );
   set_sample_rate( get_sample_rates().start() );
   set_bandwidth( 0 );
 
@@ -341,7 +343,7 @@ std::vector<std::string> hackrf_source_c::get_devices()
 {
   std::vector<std::string> devices;
   std::string label;
-
+#if 0
   for (unsigned int i = 0; i < 1 /* TODO: missing libhackrf api */; i++) {
     std::string args = "hackrf=" + boost::lexical_cast< std::string >( i );
 
@@ -354,7 +356,49 @@ std::vector<std::string> hackrf_source_c::get_devices()
     args += ",label='" + label + "'";
     devices.push_back( args );
   }
+#else
+
+  {
+    boost::mutex::scoped_lock lock( _usage_mutex );
+
+    if ( _usage == 0 )
+      hackrf_init(); /* call only once before the first open */
+
+    _usage++;
+  }
+
+  int ret;
+  hackrf_device *dev = NULL;
+  ret = hackrf_open(&dev);
+  if ( HACKRF_SUCCESS == ret )
+  {
+    std::string args = "hackrf=0";
+
+    label = "HackRF";
+
+    uint8_t board_id;
+    ret = hackrf_board_id_read( dev, &board_id );
+    if ( HACKRF_SUCCESS == ret )
+    {
+      label += std::string(" ") + hackrf_board_id_name(hackrf_board_id(board_id));
+    }
+
+    args += ",label='" + label + "'";
+    devices.push_back( args );
+
+    ret = hackrf_close(dev);
+  }
+
+  {
+    boost::mutex::scoped_lock lock( _usage_mutex );
+
+     _usage--;
+
+    if ( _usage == 0 )
+      hackrf_exit(); /* call only once after last close */
+  }
 
+#endif
   return devices;
 }