iwlwifi: add mac80211 flush callback support

Adding flush callback support in the driver. Two type of flush can be
issued by mac80211:
1. drop = true: frame drop is ok, issue REPLY_TXFIFO_FLUSH host command
to uCode to drop all the frames in tx fifo queues; then return the
control back to mac80211
2. drop = false: wait for either all the frames in tx fifo queues been
transmitted, or timeout; then return the control back to mac80211

If the flush request coming from mac80211, mac80211 will make sure there
are no additional frames push down to driver before flush operation is
completed.

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

1 files changed, 63 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
index 5f1e7d802cb..95666e565c7 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
@@ -1435,3 +1435,66 @@ void iwl_free_tfds_in_queue(struct iwl_priv *priv,
 		priv->stations[sta_id].tid[tid].tfds_in_queue = 0;
 	}
 }
+
+#define IWL_FLUSH_WAIT_MS	2000
+
+int iwlagn_wait_tx_queue_empty(struct iwl_priv *priv)
+{
+	struct iwl_tx_queue *txq;
+	struct iwl_queue *q;
+	int cnt;
+	unsigned long now = jiffies;
+	int ret = 0;
+
+	/* waiting for all the tx frames complete might take a while */
+	for (cnt = 0; cnt < priv->hw_params.max_txq_num; cnt++) {
+		if (cnt == IWL_CMD_QUEUE_NUM)
+			continue;
+		txq = &priv->txq[cnt];
+		q = &txq->q;
+		while (q->read_ptr != q->write_ptr && !time_after(jiffies,
+		       now + msecs_to_jiffies(IWL_FLUSH_WAIT_MS)))
+				msleep(1);
+
+		if (q->read_ptr != q->write_ptr) {
+			IWL_ERR(priv, "fail to flush all tx fifo queues\n");
+			ret = -ETIMEDOUT;
+			break;
+		}
+	}
+	return ret;
+}
+
+#define IWL_TX_QUEUE_MSK	0xfffff
+
+/**
+ * iwlagn_txfifo_flush: send REPLY_TXFIFO_FLUSH command to uCode
+ *
+ * pre-requirements:
+ *  1. acquire mutex before calling
+ *  2. make sure rf is on and not in exit state
+ */
+int iwlagn_txfifo_flush(struct iwl_priv *priv, u16 flush_control)
+{
+	struct iwl_txfifo_flush_cmd flush_cmd;
+	struct iwl_host_cmd cmd = {
+		.id = REPLY_TXFIFO_FLUSH,
+		.len = sizeof(struct iwl_txfifo_flush_cmd),
+		.flags = CMD_SYNC,
+		.data = &flush_cmd,
+	};
+
+	might_sleep();
+
+	memset(&flush_cmd, 0, sizeof(flush_cmd));
+	flush_cmd.fifo_control = IWL_TX_FIFO_VO_MSK | IWL_TX_FIFO_VI_MSK |
+				 IWL_TX_FIFO_BE_MSK | IWL_TX_FIFO_BK_MSK;
+	if (priv->cfg->sku & IWL_SKU_N)
+		flush_cmd.fifo_control |= IWL_AGG_TX_QUEUE_MSK;
+
+	IWL_DEBUG_INFO(priv, "fifo queue control: 0X%x\n",
+		       flush_cmd.fifo_control);
+	flush_cmd.flush_control = cpu_to_le16(flush_control);
+
+	return iwl_send_cmd(priv, &cmd);
+}