Merged in antmerlino/nuttx/xbee_timeout (pull request #629)

Xbee: Adds a timeout to send logic to handle case where XBee module fails to respond to a Transmit request with a Transmit Status

Approved-by: Gregory Nutt <gnutt@nuttx.org>

drivers/wireless/ieee802154/xbee/xbee.c

@@ -643,8 +643,10 @@ static void xbee_process_apiframes(FAR struct xbee_priv_s *priv,
             break;
           case XBEE_APIFRAME_TXSTATUS:
             {
+              wd_cancel(priv->reqdata_wd);
               xbee_process_txstatus(priv, frame->io_data[frame->io_offset],
                                     frame->io_data[frame->io_offset + 1]);
+              priv->txdone = true;
               nxsem_post(&priv->txdone_sem);
             }
             break;
@@ -1027,6 +1029,7 @@ XBEEHANDLE xbee_init(FAR struct spi_dev_s *spi,
 
   priv->assocwd    = wd_create();
   priv->atquery_wd = wd_create();
+  priv->reqdata_wd = wd_create();
 
   priv->frameid = 0; /* Frame ID should never be 0, but it is incremented
                       * in xbee_next_frameid before being used so it will be 1 */

drivers/wireless/ieee802154/xbee/xbee.h

@@ -172,9 +172,11 @@ struct xbee_priv_s
   char querycmd[2];               /* Stores the pending AT Query command */
   bool querydone;                 /* Used to tell waiting thread query is done*/
   WDOG_ID atquery_wd;             /* Support AT Query timeout and retry */
+  WDOG_ID reqdata_wd;             /* Support send timeout and retry */
   uint8_t frameid;                /* For differentiating AT request/response */
   sem_t tx_sem;                   /* Support a single pending transmit */
   sem_t txdone_sem;               /* For signalling tx is completed */
+  bool txdone;
 
   /******************* Fields related to Xbee radio ***************************/
 

drivers/wireless/ieee802154/xbee/xbee_mac.c

@@ -55,6 +55,7 @@
  ****************************************************************************/
 
 #define XBEE_ASSOC_POLLDELAY 100
+#define XBEE_RESPONSE_TIMEOUT 100
 
 /****************************************************************************
  * Private Types
@@ -149,6 +150,40 @@ static void xbee_assocworker(FAR void *arg)
   (void)wd_start(priv->assocwd, XBEE_ASSOC_POLLDELAY, xbee_assoctimer, 1, (wdparm_t)arg);
 }
 
+/****************************************************************************
+ * Name: xbee_reqdata_timeout
+ *
+ * Description:
+ *   This function runs when a send request has timed out waiting for a response
+ *   from the XBee module. This really should never happen, but if it does,
+ *   handle it gracefully by retrying the query. Although I still think this
+ *   should not happen, it does seem to happen. The XBee seemingly randomly drops
+ *   the request and never sends a response.
+ *
+ * Parameters:
+ *   argc - The number of available arguments
+ *   arg  - The first argument
+ *
+ * Returned Value:
+ *   None
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+static void xbee_reqdata_timeout(int argc, uint32_t arg, ...)
+{
+  FAR struct xbee_priv_s *priv = (FAR struct xbee_priv_s *)arg;
+
+  DEBUGASSERT(priv != NULL);
+
+  wlwarn("Send timeout\n");
+
+  /* Wake the pending reqdata thread so it can retry */
+
+  nxsem_post(&priv->txdone_sem);
+}
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -327,12 +362,25 @@ int xbee_req_data(XBEEHANDLE xbee,
   xbee_insert_checksum(&frame->io_data[frame->io_offset],
                        (frame->io_len - frame->io_offset));
 
-  xbee_send_apiframe(priv, &frame->io_data[frame->io_offset],
-                     (frame->io_len - frame->io_offset));
+  priv->txdone = false;
 
-  /* Wait for a transmit status to be received. Does not necessarily mean success */
+  do
+    {
+      /* Setup a timeout in case the XBee never responds with a tx status */
 
-  while (nxsem_wait(&priv->txdone_sem) < 0);
+      (void)wd_start(priv->reqdata_wd, XBEE_RESPONSE_TIMEOUT, xbee_reqdata_timeout,
+                     1, (wdparm_t)priv);
+
+      /* Send the frame */
+
+      xbee_send_apiframe(priv, &frame->io_data[frame->io_offset],
+                         (frame->io_len - frame->io_offset));
+
+      /* Wait for a transmit status to be received. Does not necessarily mean success */
+
+      while (nxsem_wait(&priv->txdone_sem) < 0);
+    }
+  while (!priv->txdone);
 
   nxsem_post(&priv->tx_sem);
   iob_free(frame);