Merged in antmerlino/nuttx/xbee-stability-improvements (pull request #1000)

Xbee stability improvements

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

drivers/wireless/ieee802154/xbee/Kconfig

@@ -29,4 +29,18 @@ config XBEE_NETDEV_RECVRPRIO
 		the MAC character driver (which should always be lowest priority since
 		it is a "catch-all" type receiver).
 
+config XBEE_LOCKUP_WORKAROUND
+	bool "Enable workaround to counteract XBee lockup"
+	default y
+	---help---
+		When receiving large amounts of data over the XBee, there is some probability
+		that the XBee will lockup and stop sending us data over SPI. In most cases,
+		querying the XBee will get it out of this state and communication will resume.
+		In some cases however, the XBee will freeze completely and won't ever respond
+		to our queries.
+
+		This workaround periodically queries the XBee if there hasn't been any
+		recent interaction. Additionally, if any query does not get a response
+		after 10 attempts, the XBee is reset.
+
 endif # IEEE802154_XBEE

drivers/wireless/ieee802154/xbee/xbee.h

@@ -167,6 +167,7 @@ struct xbee_priv_s
                                    * callback to registered receivers */
   WDOG_ID assocwd;                /* Association watchdog */
   struct work_s assocwork;        /* For polling for association status */
+  bool associating;               /* Are we currently associating */
   sem_t atquery_sem;              /* Only allow one AT query at a time */
   sem_t atresp_sem;               /* For signaling pending AT response received */
   char querycmd[2];               /* Stores the pending AT Query command */
@@ -177,6 +178,11 @@ struct xbee_priv_s
   sem_t tx_sem;                   /* Support a single pending transmit */
   sem_t txdone_sem;               /* For signalling tx is completed */
   bool txdone;
+#ifdef CONFIG_XBEE_LOCKUP_WORKAROUND
+  WDOG_ID lockup_wd;              /* Watchdog to protect for XBee lockup */
+  struct work_s lockupwork;       /* For deferring lockup query check to LPWORK queue*/
+  struct work_s backupwork;       /* For deferring backing up parameters to LPWORK queue*/
+#endif
 
   /******************* Fields related to Xbee radio ***************************/
 
@@ -382,7 +388,18 @@ void xbee_send_atquery(FAR struct xbee_priv_s *priv, FAR const char *atcommand);
  *
  ****************************************************************************/
 
-#define xbee_query_assoc(priv) xbee_atquery(priv "AI")
+#define xbee_query_assoc(priv) xbee_atquery(priv, "AI")
+
+/****************************************************************************
+ * Name: xbee_save_params
+ *
+ * Description:
+ *   Sends API frame with AT command request to write current parameters to
+ *   non-volatile memory so that they are used after next reset.
+ *
+ ****************************************************************************/
+
+#define xbee_save_params(priv) xbee_atquery(priv, "WR")
 
 /****************************************************************************
  * Name: xbee_set_panid

drivers/wireless/ieee802154/xbee/xbee_mac.c

@@ -58,6 +58,10 @@
 
 #define XBEE_RESPONSE_TIMEOUT MSEC2TICK(200)
 
+#ifdef CONFIG_XBEE_LOCKUP_WORKAROUND
+#define XBEE_LOCKUP_SENDATTEMPTS 20
+#endif
+
 /****************************************************************************
  * Private Types
  ****************************************************************************/
@@ -146,9 +150,12 @@ static void xbee_assocworker(FAR void *arg)
 {
   FAR struct xbee_priv_s *priv = (FAR struct xbee_priv_s *)arg;
 
-  xbee_send_atquery(priv, "AI");
+  if (priv->associating)
+    {
+      xbee_send_atquery(priv, "AI");
 
-  (void)wd_start(priv->assocwd, XBEE_ASSOC_POLLDELAY, xbee_assoctimer, 1, (wdparm_t)arg);
+      (void)wd_start(priv->assocwd, XBEE_ASSOC_POLLDELAY, xbee_assoctimer, 1, (wdparm_t)arg);
+    }
 }
 
 /****************************************************************************
@@ -303,6 +310,9 @@ int xbee_req_data(XBEEHANDLE xbee,
 #ifdef CONFIG_DEBUG_ASSERTIONS
   int prevoffs = frame->io_offset;
 #endif
+#ifdef CONFIG_XBEE_LOCKUP_WORKAROUND
+  int retries = XBEE_LOCKUP_SENDATTEMPTS;
+#endif
 
   /* Support one pending transmit at a time */
 
@@ -380,6 +390,28 @@ int xbee_req_data(XBEEHANDLE xbee,
       /* Wait for a transmit status to be received. Does not necessarily mean success */
 
       while (nxsem_wait(&priv->txdone_sem) < 0);
+
+      /* If the transmit timeout has occured, and there are no IOBs available,
+       * we may be blocking the context needed to free the IOBs. We cannot receive
+       * the Tx status because it requires an IOB. Therefore, if we have hit the
+       * timeout, and there are no IOBs, let's move on assuming the transmit was
+       * a success
+       */
+
+      if (!priv->txdone && iob_navail(false) <= 0)
+        {
+          wlwarn("Couldn't confirm TX. No IOBs\n");
+          break;
+        }
+
+#ifdef CONFIG_XBEE_LOCKUP_WORKAROUND
+      if (--retries == 0 && !priv->txdone)
+        {
+          wlerr("XBee not responding. Resetting.\n");
+          priv->lower->reset(priv->lower);
+          retries = XBEE_LOCKUP_SENDATTEMPTS;
+        }
+#endif
     }
   while (!priv->txdone);
 
@@ -646,6 +678,8 @@ int xbee_req_associate(XBEEHANDLE xbee, FAR struct ieee802154_assoc_req_s *req)
 
   xbee_set_epassocflags(priv, XBEE_EPASSOCFLAGS_AUTOASSOC);
 
+  priv->associating = true;
+
   /* In order to track the association status, we must poll the device for
    * an update.
    */