ath: Speedup key set/reset ops for HTC driver

By enabling buffered register write for ath9k_htc driver
avoids unnecessary dissociation while rekeying phase under
heavy traffic exchange.
Signed-off-by: NRajkumar Manoharan <rmanoharan@atheros.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/key.c

@@ -23,6 +23,14 @@
 
 #define REG_READ			(common->ops->read)
 #define REG_WRITE(_ah, _reg, _val)	(common->ops->write)(_ah, _val, _reg)
+#define ENABLE_REGWRITE_BUFFER(_ah)			\
+	if (common->ops->enable_write_buffer)		\
+		common->ops->enable_write_buffer((_ah));
+
+#define REGWRITE_BUFFER_FLUSH(_ah)			\
+	if (common->ops->write_flush)			\
+		common->ops->write_flush((_ah));
+
 
 #define IEEE80211_WEP_NKID      4       /* number of key ids */
 
@@ -42,6 +50,8 @@ bool ath_hw_keyreset(struct ath_common *common, u16 entry)
 
 	keyType = REG_READ(ah, AR_KEYTABLE_TYPE(entry));
 
+	ENABLE_REGWRITE_BUFFER(ah);
+
 	REG_WRITE(ah, AR_KEYTABLE_KEY0(entry), 0);
 	REG_WRITE(ah, AR_KEYTABLE_KEY1(entry), 0);
 	REG_WRITE(ah, AR_KEYTABLE_KEY2(entry), 0);
@@ -66,6 +76,8 @@ bool ath_hw_keyreset(struct ath_common *common, u16 entry)
 
 	}
 
+	REGWRITE_BUFFER_FLUSH(ah);
+
 	return true;
 }
 EXPORT_SYMBOL(ath_hw_keyreset);
@@ -104,9 +116,13 @@ static bool ath_hw_keysetmac(struct ath_common *common,
 	} else {
 		macLo = macHi = 0;
 	}
+	ENABLE_REGWRITE_BUFFER(ah);
+
 	REG_WRITE(ah, AR_KEYTABLE_MAC0(entry), macLo);
 	REG_WRITE(ah, AR_KEYTABLE_MAC1(entry), macHi | unicast_flag);
 
+	REGWRITE_BUFFER_FLUSH(ah);
+
 	return true;
 }
 
@@ -223,6 +239,8 @@ static bool ath_hw_set_keycache_entry(struct ath_common *common, u16 entry,
 			mic3 = get_unaligned_le16(k->kv_txmic + 0) & 0xffff;
 			mic4 = get_unaligned_le32(k->kv_txmic + 4);
 
+			ENABLE_REGWRITE_BUFFER(ah);
+
 			/* Write RX[31:0] and TX[31:16] */
 			REG_WRITE(ah, AR_KEYTABLE_KEY0(micentry), mic0);
 			REG_WRITE(ah, AR_KEYTABLE_KEY1(micentry), mic1);
@@ -236,6 +254,8 @@ static bool ath_hw_set_keycache_entry(struct ath_common *common, u16 entry,
 			REG_WRITE(ah, AR_KEYTABLE_TYPE(micentry),
 				  AR_KEYTABLE_TYPE_CLR);
 
+			REGWRITE_BUFFER_FLUSH(ah);
+
 		} else {
 			/*
 			 * TKIP uses four key cache entries (two for group
@@ -258,6 +278,8 @@ static bool ath_hw_set_keycache_entry(struct ath_common *common, u16 entry,
 			mic0 = get_unaligned_le32(k->kv_mic + 0);
 			mic2 = get_unaligned_le32(k->kv_mic + 4);
 
+			ENABLE_REGWRITE_BUFFER(ah);
+
 			/* Write MIC key[31:0] */
 			REG_WRITE(ah, AR_KEYTABLE_KEY0(micentry), mic0);
 			REG_WRITE(ah, AR_KEYTABLE_KEY1(micentry), 0);
@@ -270,8 +292,12 @@ static bool ath_hw_set_keycache_entry(struct ath_common *common, u16 entry,
 			REG_WRITE(ah, AR_KEYTABLE_KEY4(micentry), 0);
 			REG_WRITE(ah, AR_KEYTABLE_TYPE(micentry),
 				  AR_KEYTABLE_TYPE_CLR);
+
+			REGWRITE_BUFFER_FLUSH(ah);
 		}
 
+		ENABLE_REGWRITE_BUFFER(ah);
+
 		/* MAC address registers are reserved for the MIC entry */
 		REG_WRITE(ah, AR_KEYTABLE_MAC0(micentry), 0);
 		REG_WRITE(ah, AR_KEYTABLE_MAC1(micentry), 0);
@@ -283,7 +309,11 @@ static bool ath_hw_set_keycache_entry(struct ath_common *common, u16 entry,
 		 */
 		REG_WRITE(ah, AR_KEYTABLE_KEY0(entry), key0);
 		REG_WRITE(ah, AR_KEYTABLE_KEY1(entry), key1);
+
+		REGWRITE_BUFFER_FLUSH(ah);
 	} else {
+		ENABLE_REGWRITE_BUFFER(ah);
+
 		/* Write key[47:0] */
 		REG_WRITE(ah, AR_KEYTABLE_KEY0(entry), key0);
 		REG_WRITE(ah, AR_KEYTABLE_KEY1(entry), key1);
@@ -296,6 +326,8 @@ static bool ath_hw_set_keycache_entry(struct ath_common *common, u16 entry,
 		REG_WRITE(ah, AR_KEYTABLE_KEY4(entry), key4);
 		REG_WRITE(ah, AR_KEYTABLE_TYPE(entry), keyType);
 
+		REGWRITE_BUFFER_FLUSH(ah);
+
 		/* Write MAC address for the entry */
 		(void) ath_hw_keysetmac(common, entry, mac);
 	}