1 files changed, 93 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-core.c b/drivers/net/wireless/iwlwifi/iwl-core.c
index d4c2a3e17c5..5180fb24cd3 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.c
+++ b/drivers/net/wireless/iwlwifi/iwl-core.c
@@ -3051,6 +3051,99 @@ int iwl_force_reset(struct iwl_priv *priv, int mode)
         }
         return 0;
 }
+EXPORT_SYMBOL(iwl_force_reset);
+
+/**
+ * iwl_bg_monitor_recover - Timer callback to check for stuck queue and recover
+ *
+ * During normal condition (no queue is stuck), the timer is continually set to
+ * execute every monitor_recover_period milliseconds after the last timer
+ * expired.  When the queue read_ptr is at the same place, the timer is
+ * shorten to 100mSecs.  This is
+ *      1) to reduce the chance that the read_ptr may wrap around (not stuck)
+ *      2) to detect the stuck queues quicker before the station and AP can
+ *      disassociate each other.
+ *
+ * This function monitors all the tx queues and recover from it if any
+ * of the queues are stuck.
+ * 1. It first check the cmd queue for stuck conditions.  If it is stuck,
+ *      it will recover by resetting the firmware and return.
+ * 2. Then, it checks for station association.  If it associates it will check
+ *      other queues.  If any queue is stuck, it will recover by resetting
+ *      the firmware.
+ * Note: It the number of times the queue read_ptr to be at the same place to
+ *      be MAX_REPEAT+1 in order to consider to be stuck.
+ */
+/*
+ * The maximum number of times the read pointer of the tx queue at the
+ * same place without considering to be stuck.
+ */
+#define MAX_REPEAT      (2)
+static int iwl_check_stuck_queue(struct iwl_priv *priv, int cnt)
+{
+        struct iwl_tx_queue *txq;
+        struct iwl_queue *q;
+
+        txq = &priv->txq[cnt];
+        q = &txq->q;
+        /* queue is empty, skip */
+        if (q->read_ptr != q->write_ptr) {
+                if (q->read_ptr == q->last_read_ptr) {
+                        /* a queue has not been read from last time */
+                        if (q->repeat_same_read_ptr > MAX_REPEAT) {
+                                IWL_ERR(priv,
+                                        "queue %d stuck %d time. Fw reload.\n",
+                                        q->id, q->repeat_same_read_ptr);
+                                q->repeat_same_read_ptr = 0;
+                                iwl_force_reset(priv, IWL_FW_RESET);
+                        } else {
+                                q->repeat_same_read_ptr++;
+                                IWL_DEBUG_RADIO(priv,
+                                                "queue %d, not read %d time\n",
+                                                q->id,
+                                                q->repeat_same_read_ptr);
+                                mod_timer(&priv->monitor_recover, jiffies +
+                                        msecs_to_jiffies(IWL_ONE_HUNDRED_MSECS));
+                        }
+                        return 1;
+                } else {
+                        q->last_read_ptr = q->read_ptr;
+                        q->repeat_same_read_ptr = 0;
+                }
+        }
+        return 0;
+}
+
+void iwl_bg_monitor_recover(unsigned long data)
+{
+        struct iwl_priv *priv = (struct iwl_priv *)data;
+        int cnt;
+
+        if (test_bit(STATUS_EXIT_PENDING, &priv->status))
+                return;
+
+        /* monitor and check for stuck cmd queue */
+        if (iwl_check_stuck_queue(priv, IWL_CMD_QUEUE_NUM))
+                return;
+
+        /* monitor and check for other stuck queues */
+        if (iwl_is_associated(priv)) {
+                for (cnt = 0; cnt < priv->hw_params.max_txq_num; cnt++) {
+                        /* skip as we already checked the command queue */
+                        if (cnt == IWL_CMD_QUEUE_NUM)
+                                continue;
+                        if (iwl_check_stuck_queue(priv, cnt))
+                                return;
+                }
+        }
+        /*
+         * Reschedule the timer to occur in
+         * priv->cfg->monitor_recover_period
+         */
+        mod_timer(&priv->monitor_recover,
+                jiffies + msecs_to_jiffies(priv->cfg->monitor_recover_period));
+}
+EXPORT_SYMBOL(iwl_bg_monitor_recover);
 
 #ifdef CONFIG_PM