[PATCH v2 1/7] ath5k: optimize tx descriptor setup

[Felix Fietkau <nbd@openwrt.org>]

Use local variables to reduce the number of load/store operations on uncached
memory.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 drivers/net/wireless/ath/ath5k/desc.c |   45 +++++++++++++++++++--------------
 1 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/drivers/net/wireless/ath/ath5k/desc.c b/drivers/net/wireless/ath/ath5k/desc.c
index 16b44ff..6996d55 100644
--- a/drivers/net/wireless/ath/ath5k/desc.c
+++ b/drivers/net/wireless/ath/ath5k/desc.c
@@ -185,6 +185,12 @@ static int ath5k_hw_setup_4word_tx_desc(struct ath5k_hw *ah,
 	struct ath5k_hw_4w_tx_ctl *tx_ctl;
 	unsigned int frame_len;
 
+	/*
+	 * Use local variables for these to reduce load/store access on
+	 * uncached memory
+	 */
+	u32 txctl0 = 0, txctl1 = 0, txctl2 = 0, txctl3 = 0;
+
 	tx_ctl = &desc->ud.ds_tx5212.tx_ctl;
 
 	/*
@@ -208,8 +214,9 @@ static int ath5k_hw_setup_4word_tx_desc(struct ath5k_hw *ah,
 	if (tx_power > AR5K_TUNE_MAX_TXPOWER)
 		tx_power = AR5K_TUNE_MAX_TXPOWER;
 
-	/* Clear descriptor */
-	memset(&desc->ud.ds_tx5212, 0, sizeof(struct ath5k_hw_5212_tx_desc));
+	/* Clear descriptor status area */
+	memset(&desc->ud.ds_tx5212.tx_stat, 0,
+	       sizeof(desc->ud.ds_tx5212.tx_stat));
 
 	/* Setup control descriptor */
 
@@ -221,7 +228,7 @@ static int ath5k_hw_setup_4word_tx_desc(struct ath5k_hw *ah,
 	if (frame_len & ~AR5K_4W_TX_DESC_CTL0_FRAME_LEN)
 		return -EINVAL;
 
-	tx_ctl->tx_control_0 = frame_len & AR5K_4W_TX_DESC_CTL0_FRAME_LEN;
+	txctl0 = frame_len & AR5K_4W_TX_DESC_CTL0_FRAME_LEN;
 
 	/* Verify and set buffer length */
 
@@ -232,21 +239,17 @@ static int ath5k_hw_setup_4word_tx_desc(struct ath5k_hw *ah,
 	if (pkt_len & ~AR5K_4W_TX_DESC_CTL1_BUF_LEN)
 		return -EINVAL;
 
-	tx_ctl->tx_control_1 = pkt_len & AR5K_4W_TX_DESC_CTL1_BUF_LEN;
+	txctl1 = pkt_len & AR5K_4W_TX_DESC_CTL1_BUF_LEN;
 
-	tx_ctl->tx_control_0 |=
-		AR5K_REG_SM(tx_power, AR5K_4W_TX_DESC_CTL0_XMIT_POWER) |
-		AR5K_REG_SM(antenna_mode, AR5K_4W_TX_DESC_CTL0_ANT_MODE_XMIT);
-	tx_ctl->tx_control_1 |= AR5K_REG_SM(type,
-					AR5K_4W_TX_DESC_CTL1_FRAME_TYPE);
-	tx_ctl->tx_control_2 = AR5K_REG_SM(tx_tries0,
-					AR5K_4W_TX_DESC_CTL2_XMIT_TRIES0);
-	tx_ctl->tx_control_3 = tx_rate0 & AR5K_4W_TX_DESC_CTL3_XMIT_RATE0;
+	txctl0 |= AR5K_REG_SM(tx_power, AR5K_4W_TX_DESC_CTL0_XMIT_POWER) |
+		  AR5K_REG_SM(antenna_mode, AR5K_4W_TX_DESC_CTL0_ANT_MODE_XMIT);
+	txctl1 |= AR5K_REG_SM(type, AR5K_4W_TX_DESC_CTL1_FRAME_TYPE);
+	txctl2 = AR5K_REG_SM(tx_tries0, AR5K_4W_TX_DESC_CTL2_XMIT_TRIES0);
+	txctl3 = tx_rate0 & AR5K_4W_TX_DESC_CTL3_XMIT_RATE0;
 
 #define _TX_FLAGS(_c, _flag)					\
 	if (flags & AR5K_TXDESC_##_flag) {			\
-		tx_ctl->tx_control_##_c |=			\
-			AR5K_4W_TX_DESC_CTL##_c##_##_flag;	\
+		txctl##_c |= AR5K_4W_TX_DESC_CTL##_c##_##_flag;	\
 	}
 
 	_TX_FLAGS(0, CLRDMASK);
@@ -262,8 +265,8 @@ static int ath5k_hw_setup_4word_tx_desc(struct ath5k_hw *ah,
 	 * WEP crap
 	 */
 	if (key_index != AR5K_TXKEYIX_INVALID) {
-		tx_ctl->tx_control_0 |= AR5K_4W_TX_DESC_CTL0_ENCRYPT_KEY_VALID;
-		tx_ctl->tx_control_1 |= AR5K_REG_SM(key_index,
+		txctl0 |= AR5K_4W_TX_DESC_CTL0_ENCRYPT_KEY_VALID;
+		txctl1 |= AR5K_REG_SM(key_index,
 				AR5K_4W_TX_DESC_CTL1_ENCRYPT_KEY_IDX);
 	}
 
@@ -274,12 +277,16 @@ static int ath5k_hw_setup_4word_tx_desc(struct ath5k_hw *ah,
 		if ((flags & AR5K_TXDESC_RTSENA) &&
 				(flags & AR5K_TXDESC_CTSENA))
 			return -EINVAL;
-		tx_ctl->tx_control_2 |= rtscts_duration &
-				AR5K_4W_TX_DESC_CTL2_RTS_DURATION;
-		tx_ctl->tx_control_3 |= AR5K_REG_SM(rtscts_rate,
+		txctl2 |= rtscts_duration & AR5K_4W_TX_DESC_CTL2_RTS_DURATION;
+		txctl3 |= AR5K_REG_SM(rtscts_rate,
 				AR5K_4W_TX_DESC_CTL3_RTS_CTS_RATE);
 	}
 
+	tx_ctl->tx_control_0 = txctl0;
+	tx_ctl->tx_control_1 = txctl1;
+	tx_ctl->tx_control_2 = txctl2;
+	tx_ctl->tx_control_3 = txctl3;
+
 	return 0;
 }
 
-- 
1.7.3.2