From efdcd66a2f33340588b67660f2642f5eec2e1915 Mon Sep 17 00:00:00 2001
From: Thomas Tsou <tom@tsou.cc>
Date: Thu, 17 Oct 2013 06:18:56 +0000
Subject: [PATCH] Transceiver52M: Separate main transmit and receive drive
 threads

This patch primarily addresses observed repeated overrun
conditions in embedded environments - namely ARM.

The heartbeat of the transceiver is derived from the receive
sample stream, which drives the main GSM clock. Detach the
transmit thread from the receive loop to avoid interfering with
the receive I/O, which is sensitive to overrun conditions if
pull process is interrupted.

Signed-off-by: Thomas Tsou <tom@tsou.cc>

git-svn-id: http://wush.net/svn/range/software/public/openbts/trunk@6745 19bc5d8c-e614-43d4-8b26-e1612bc8e597
---
 Transceiver52M/Transceiver.cpp | 27 ++++++++++++++++-----------
 Transceiver52M/Transceiver.h   | 12 ++++++++----
 2 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/Transceiver52M/Transceiver.cpp b/Transceiver52M/Transceiver.cpp
index efa2d0a..1f85242 100644
--- a/Transceiver52M/Transceiver.cpp
+++ b/Transceiver52M/Transceiver.cpp
@@ -57,7 +57,8 @@ Transceiver::Transceiver(int wBasePort,
 {
   GSM::Time startTime(random() % gHyperframe,0);
 
-  mFIFOServiceLoopThread = new Thread(32768);  ///< thread to push bursts into transmit FIFO
+  mRxServiceLoopThread = new Thread(32768);
+  mTxServiceLoopThread = new Thread(32768);
   mControlServiceLoopThread = new Thread(32768);       ///< thread to process control messages from GSM core
   mTransmitPriorityQueueServiceLoopThread = new Thread(32768);///< thread to process transmit bursts from GSM core
 
@@ -527,7 +528,8 @@ void Transceiver::driveControl()
         mRadioInterface->start();
 
         // Start radio interface threads.
-        mFIFOServiceLoopThread->start((void * (*)(void*))FIFOServiceLoopAdapter,(void*) this);
+        mTxServiceLoopThread->start((void * (*)(void*))TxServiceLoopAdapter,(void*) this);
+        mRxServiceLoopThread->start((void * (*)(void*))RxServiceLoopAdapter,(void*) this);
         mTransmitPriorityQueueServiceLoopThread->start((void * (*)(void*))TransmitPriorityQueueServiceLoopAdapter,(void*) this);
         writeClockInterface();
 
@@ -836,11 +838,9 @@ void Transceiver::driveTransmitFIFO()
       pushRadioVector(mTransmitDeadlineClock);
       mTransmitDeadlineClock.incTN();
     }
-    
   }
-  // FIXME -- This should not be a hard spin.
-  // But any delay here causes us to throw omni_thread_fatal.
-  //else radioClock->wait();
+
+  radioClock->wait();
 }
 
 
@@ -857,17 +857,22 @@ void Transceiver::writeClockInterface()
 
   mLastClockUpdateTime = mTransmitDeadlineClock;
 
-}   
-  
+}
 
-
-
-void *FIFOServiceLoopAdapter(Transceiver *transceiver)
+void *RxServiceLoopAdapter(Transceiver *transceiver)
 {
   transceiver->setPriority();
 
   while (1) {
     transceiver->driveReceiveFIFO();
+    pthread_testcancel();
+  }
+  return NULL;
+}
+
+void *TxServiceLoopAdapter(Transceiver *transceiver)
+{
+  while (1) {
     transceiver->driveTransmitFIFO();
     pthread_testcancel();
   }
diff --git a/Transceiver52M/Transceiver.h b/Transceiver52M/Transceiver.h
index c88c589..dea10f4 100644
--- a/Transceiver52M/Transceiver.h
+++ b/Transceiver52M/Transceiver.h
@@ -56,7 +56,8 @@ private:
   VectorFIFO*  mTransmitFIFO;     ///< radioInterface FIFO of transmit bursts 
   VectorFIFO*  mReceiveFIFO;      ///< radioInterface FIFO of receive bursts 
 
-  Thread *mFIFOServiceLoopThread;  ///< thread to push/pull bursts into transmit/receive FIFO
+  Thread *mRxServiceLoopThread;   ///< thread to pull bursts into receive FIFO
+  Thread *mTxServiceLoopThread;   ///< thread to push bursts into transmit FIFO
   Thread *mControlServiceLoopThread;       ///< thread to process control messages from GSM core
   Thread *mTransmitPriorityQueueServiceLoopThread;///< thread to process transmit bursts from GSM core
 
@@ -193,7 +194,9 @@ protected:
   */
   bool driveTransmitPriorityQueue();
 
-  friend void *FIFOServiceLoopAdapter(Transceiver *);
+  friend void *RxServiceLoopAdapter(Transceiver *);
+
+  friend void *TxServiceLoopAdapter(Transceiver *);
 
   friend void *ControlServiceLoopAdapter(Transceiver *);
 
@@ -206,8 +209,9 @@ protected:
 
 };
 
-/** FIFO thread loop */
-void *FIFOServiceLoopAdapter(Transceiver *);
+/** Main drive threads */
+void *RxServiceLoopAdapter(Transceiver *);
+void *TxServiceLoopAdapter(Transceiver *);
 
 /** control message handler thread loop */
 void *ControlServiceLoopAdapter(Transceiver *);