Add a generic function for tx write out of order (timestamps not increasing)

Add an API to allow out-of-order writes to a radio interface, unlike the
current interface.

this function is called in UE in this commit, even if the tx might
still be in order.

Later, i plan to improve UE pulti-threading, that will lead to out of
order tx.  also, the gNB will benefit of this new function to replace
several specific pieces of code that reorder tx with over complex and
slow systems

radio/COMMON/common_lib.h

@@ -384,6 +384,22 @@ typedef struct fhstate_s {
   int active;
 } fhstate_t;
 
+#define WRITE_QUEUE_SZ 20
+typedef struct {
+  bool initDone;
+  pthread_mutex_t mutex_write;
+  pthread_mutex_t mutex_store;
+  openair0_timestamp nextTS;
+  struct {
+    bool active;
+    openair0_timestamp timestamp;
+    void *txp[NB_ANTENNAS_TX];
+    int nsamps;
+    int nbAnt;
+    int flags;
+  } queue[WRITE_QUEUE_SZ];
+} re_order_t;
+
 /*!\brief structure holds the parameters to configure USRP devices */
 struct openair0_device_t {
   /*!tx write thread*/
@@ -586,6 +602,7 @@ struct openair0_device_t {
   /* \brief timing statistics for TX fronthaul (ethernet)
    */
   time_stats_t tx_fhaul;
+  re_order_t reOrder;
 };
 
 /* type of device init function, implemented in shared lib */
@@ -654,6 +671,7 @@ extern int read_recplayconfig(recplay_conf_t **recplay_conf, recplay_state_t **r
 /*! \brief store recorded iqs from memory to file. */
 extern void iqrecorder_end(openair0_device *device);
 
+int openair0_write_reorder(openair0_device *device, openair0_timestamp timestamp, void **txp, int nsamps, int nbAnt, int flags);
 
 #include <unistd.h>
 #ifndef gettid