radioInterface: Atomically fetch and change underrun variable

Otherwise, it could happen that underrun events are lost:
TxLower (isUnderrun):	RxLower (pullBuffer):
read(underrun)
			read(underrun)
			write(underrun, |val) [maybe underrun becomes TRUE]
write(underrun, false)

Similary, it could happen the other direction if atomic was only applied
to isUnderrun:
TxLower (isUnderrun):	RxLower (pullBuffer):
			read(underrun) -> true
read(underrun)-> true
write(underrun, false)
			write(underrun, true|val) where val=false

So in here isUnderrun would return true twice while it should only
return one.

Change-Id: I684e0a5d2a9583a161d5a6593559b3a9e7cd57e3

1 files changed, 26 insertions, 2 deletions

diff --git a/CommonLibs/Threads.h b/CommonLibs/Threads.h
index 4cc0884..df61c72 100644
--- a/CommonLibs/Threads.h
+++ b/CommonLibs/Threads.h
@@ -28,6 +28,8 @@
 #ifndef THREADS_H
 #define THREADS_H
 
+#include "config.h"
+
 #include <pthread.h>
 #include <iostream>
 #include <assert.h>
@@ -188,8 +190,30 @@ class Thread {
 	void cancel() { pthread_cancel(mThread); }
 };
 
-
-
+#ifdef HAVE_ATOMIC_OPS
+#define osmo_trx_sync_fetch_and_and(ptr, value) __sync_fetch_and_and((ptr), (value))
+#define osmo_trx_sync_or_and_fetch(ptr, value) __sync_or_and_fetch((ptr), (value))
+#else
+extern pthread_mutex_t atomic_ops_mutex;
+static inline int osmo_trx_sync_fetch_and_and(int *ptr, int value)
+{
+	pthread_mutex_lock(&atomic_ops_mutex);
+	int tmp = *ptr;
+	*ptr &= value;
+	pthread_mutex_unlock(&atomic_ops_mutex);
+	return tmp;
+}
+
+static inline int osmo_trx_sync_or_and_fetch(int *ptr, int value)
+{
+	int tmp;
+	pthread_mutex_lock(&atomic_ops_mutex);
+	*ptr |= value;
+	tmp = *ptr;
+	pthread_mutex_unlock(&atomic_ops_mutex);
+	return tmp;
+}
+#endif
 
 #endif
 // vim: ts=4 sw=4