iwlwifi: avoid Tx queue memory allocation in interface down

We used to free all the Tx queues memory when interface is brought
down and reallocate them again in interface up. This requires
order-4 allocation for txq->cmd[]. In situations like s2ram, this
usually leads to allocation failure in the memory subsystem. The
patch fixed this problem by allocating the Tx queues memory only at
the first time. Later iwl_down/iwl_up only initialize but don't
free and reallocate them. The memory is freed at the device removal
time. BTW, we have already done this for the Rx queue.

This fixed bug https://bugzilla.kernel.org/show_bug.cgi?id=15551

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

1 files changed, 29 insertions, 10 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
index a76e14351b5a..3077eac58880 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
@@ -809,8 +809,7 @@ void iwlagn_hw_txq_ctx_free(struct iwl_priv *priv)
 
 	/* Tx queues */
 	if (priv->txq) {
-		for (txq_id = 0; txq_id < priv->hw_params.max_txq_num;
-		     txq_id++)
+		for (txq_id = 0; txq_id < priv->hw_params.max_txq_num; txq_id++)
 			if (txq_id == IWL_CMD_QUEUE_NUM)
 				iwl_cmd_queue_free(priv);
 			else
@@ -825,15 +824,15 @@ void iwlagn_hw_txq_ctx_free(struct iwl_priv *priv)
 }
 
 /**
- * iwlagn_txq_ctx_reset - Reset TX queue context
- * Destroys all DMA structures and initialize them again
+ * iwlagn_txq_ctx_alloc - allocate TX queue context
+ * Allocate all Tx DMA structures and initialize them
  *
  * @param priv
  * @return error code
  */
-int iwlagn_txq_ctx_reset(struct iwl_priv *priv)
+int iwlagn_txq_ctx_alloc(struct iwl_priv *priv)
 {
-	int ret = 0;
+	int ret;
 	int txq_id, slots_num;
 	unsigned long flags;
 
@@ -891,8 +890,31 @@ int iwlagn_txq_ctx_reset(struct iwl_priv *priv)
 	return ret;
 }
 
+void iwlagn_txq_ctx_reset(struct iwl_priv *priv)
+{
+	int txq_id, slots_num;
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	/* Turn off all Tx DMA fifos */
+	priv->cfg->ops->lib->txq_set_sched(priv, 0);
+
+	/* Tell NIC where to find the "keep warm" buffer */
+	iwl_write_direct32(priv, FH_KW_MEM_ADDR_REG, priv->kw.dma >> 4);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	/* Alloc and init all Tx queues, including the command queue (#4) */
+	for (txq_id = 0; txq_id < priv->hw_params.max_txq_num; txq_id++) {
+		slots_num = txq_id == IWL_CMD_QUEUE_NUM ?
+			    TFD_CMD_SLOTS : TFD_TX_CMD_SLOTS;
+		iwl_tx_queue_reset(priv, &priv->txq[txq_id], slots_num, txq_id);
+	}
+}
+
 /**
- * iwlagn_txq_ctx_stop - Stop all Tx DMA channels, free Tx queue memory
+ * iwlagn_txq_ctx_stop - Stop all Tx DMA channels
  */
 void iwlagn_txq_ctx_stop(struct iwl_priv *priv)
 {
@@ -912,9 +934,6 @@ void iwlagn_txq_ctx_stop(struct iwl_priv *priv)
 				    1000);
 	}
 	spin_unlock_irqrestore(&priv->lock, flags);
-
-	/* Deallocate memory for all Tx queues */
-	iwlagn_hw_txq_ctx_free(priv);
 }
 
 /*