add condtional variable for PHY initialization and configuration

adding a cond variable and mutex to protect init and (re-)config of PHY
currently this is only used during init. If the stack couldn't be
initialized but the PHY init thread was already started, we need to
properly wait until this is done

srsue/hdr/phy/phy.h

@@ -134,7 +134,9 @@ public:
 private:
   void run_thread() final;
 
-  bool     initiated   = false;
+  std::mutex              config_mutex;
+  std::condition_variable config_cond;
+  bool                    is_configured = false;
   uint32_t nof_workers = 0;
 
   const static int SF_RECV_THREAD_PRIO = 1;

srsue/src/phy/phy.cc

@@ -122,6 +122,7 @@ int phy::init(const phy_args_t& args_, stack_interface_phy_lte* stack_, srslte::
 
 int phy::init(const phy_args_t& args_)
 {
+  std::unique_lock<std::mutex> lock(config_mutex);
   mlockall(MCL_CURRENT | MCL_FUTURE);
 
   args = args_;
@@ -172,7 +173,7 @@ int phy::init(const phy_args_t& args_)
     this->log_phy_lib_h = nullptr;
   }
 
-  initiated = false;
+  is_configured = false;
   start();
   return true;
 }
@@ -180,6 +181,7 @@ int phy::init(const phy_args_t& args_)
 // Initializes PHY in a thread
 void phy::run_thread()
 {
+  std::unique_lock<std::mutex> lock(config_mutex);
   prach_buffer.init(SRSLTE_MAX_PRB, log_h);
   common.init(&args, (srslte::log*)log_vec[0].get(), radio, stack);
 
@@ -213,22 +215,28 @@ void phy::run_thread()
   // Disable UL signal pregeneration until the attachment
   enable_pregen_signals(false);
 
-  initiated = true;
+  is_configured = true;
+  config_cond.notify_all();
 }
 
 void phy::wait_initialize()
 {
-  wait_thread_finish();
+  // wait until PHY is configured
+  std::unique_lock<std::mutex> lock(config_mutex);
+  while (!is_configured) {
+    config_cond.wait(lock);
+  }
 }
 
 bool phy::is_initiated()
 {
-  return initiated;
+  return is_configured;
 }
 
 void phy::stop()
 {
-  if (initiated) {
+  std::unique_lock<std::mutex> lock(config_mutex);
+  if (is_configured) {
     sfsync.stop();
     for (uint32_t i = 0; i < args.nof_radios - 1; i++) {
       scell_sync.at(i)->stop();
@@ -237,7 +245,7 @@ void phy::stop()
     workers_pool.stop();
     prach_buffer.stop();
 
-    initiated = false;
+    is_configured = false;
   }
 }