iwlwifi: add documentation for bt reduced tx power

[firefly-linux-kernel-4.4.55.git] / drivers / net / wireless / iwlwifi / iwl-agn-lib.c

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
index 9d88565cabf87aceb25d7e1598af2cb7e73e583b..cb4b31f658c3db2de81625a2289cd4b1171e812c 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
@@ -274,9 +274,20 @@ void iwlagn_send_advance_bt_config(struct iwl_priv *priv)
                return;
        }
 
+       /*
+        * Possible situations when BT needs to take over for receive,
+        * at the same time where STA needs to response to AP's frame(s),
+        * reduce the tx power of the required response frames, by that,
+        * allow the concurrent BT receive & WiFi transmit
+        * (BT - ANT A, WiFi -ANT B), without interference to one another
+        *
+        * Reduced tx power apply to control frames only (ACK/Back/CTS)
+        * when indicated by the BT config command
+        */
        basic.kill_ack_mask = priv->kill_ack_mask;
        basic.kill_cts_mask = priv->kill_cts_mask;
-       basic.reduce_txpower = priv->reduced_txpower;
+       if (priv->reduced_txpower)
+               basic.reduce_txpower = IWLAGN_BT_REDUCED_TX_PWR;
        basic.valid = priv->bt_valid;
 
        /*
@@ -590,6 +601,15 @@ static bool iwlagn_set_kill_msk(struct iwl_priv *priv,
        return need_update;
 }
 
+/*
+ * Upon RSSI changes, sends a bt config command with following changes
+ *  1. enable/disable "reduced control frames tx power
+ *  2. update the "kill)ack_mask" and "kill_cts_mask"
+ *
+ * If "reduced tx power" is enabled, uCode shall
+ *  1. ACK/Back/CTS rate shall reduced to 6Mbps
+ *  2. not use duplciate 20/40MHz mode
+ */
 static bool iwlagn_fill_txpower_mode(struct iwl_priv *priv,
                                struct iwl_bt_uart_msg *uart_msg)
 {