ath9k: remove ah->mask_reg, it's never used properly

ah->mask_reg was used to hold different data throughout the driver.
ath9k_hw_init_interrupt_masks() used it to save the value written to
AR_IMR.  ath9k_hw_set_interrupts() used it to hold the interrupt mask as
defined in enum ath9k_int.  Those masks differ in many bits.

Use ah->imask instead of ah->mask_reg in ath9k_hw_set_interrupts() and
ath9k_hw_updatetxtriglevel().  That's what the code was meant to do.
ah->imask is initialized in ath9k_start(), so we don't need to
initialize it from ah->mask_reg.

Once it's done, ah->mask_reg becomes write-only, so it's replaced with a
local variable in ath9k_hw_init_interrupt_masks().

Signed-off-by: Pavel Roskin <proski@gnu.org>
Reported-by: Julia Lawall <julia@diku.dk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/hw.c

@@ -1120,23 +1120,23 @@ static void ath9k_hw_init_chain_masks(struct ath_hw *ah)
 static void ath9k_hw_init_interrupt_masks(struct ath_hw *ah,
 					  enum nl80211_iftype opmode)
 {
-	ah->mask_reg = AR_IMR_TXERR |
+	u32 imr_reg = AR_IMR_TXERR |
 		AR_IMR_TXURN |
 		AR_IMR_RXERR |
 		AR_IMR_RXORN |
 		AR_IMR_BCNMISC;
 
 	if (ah->config.rx_intr_mitigation)
-		ah->mask_reg |= AR_IMR_RXINTM | AR_IMR_RXMINTR;
+		imr_reg |= AR_IMR_RXINTM | AR_IMR_RXMINTR;
 	else
-		ah->mask_reg |= AR_IMR_RXOK;
+		imr_reg |= AR_IMR_RXOK;
 
-	ah->mask_reg |= AR_IMR_TXOK;
+	imr_reg |= AR_IMR_TXOK;
 
 	if (opmode == NL80211_IFTYPE_AP)
-		ah->mask_reg |= AR_IMR_MIB;
+		imr_reg |= AR_IMR_MIB;
 
-	REG_WRITE(ah, AR_IMR, ah->mask_reg);
+	REG_WRITE(ah, AR_IMR, imr_reg);
 	ah->imrs2_reg |= AR_IMR_S2_GTT;
 	REG_WRITE(ah, AR_IMR_S2, ah->imrs2_reg);
 
@@ -2839,7 +2839,7 @@ EXPORT_SYMBOL(ath9k_hw_getisr);
 
 enum ath9k_int ath9k_hw_set_interrupts(struct ath_hw *ah, enum ath9k_int ints)
 {
-	u32 omask = ah->mask_reg;
+	enum ath9k_int omask = ah->imask;
 	u32 mask, mask2;
 	struct ath9k_hw_capabilities *pCap = &ah->caps;
 	struct ath_common *common = ath9k_hw_common(ah);
@@ -2911,7 +2911,6 @@ enum ath9k_int ath9k_hw_set_interrupts(struct ath_hw *ah, enum ath9k_int ints)
 			   AR_IMR_S2_TSFOOR | AR_IMR_S2_GTT | AR_IMR_S2_CST);
 	ah->imrs2_reg |= mask2;
 	REG_WRITE(ah, AR_IMR_S2, ah->imrs2_reg);
-	ah->mask_reg = ints;
 
 	if (!(pCap->hw_caps & ATH9K_HW_CAP_AUTOSLEEP)) {
 		if (ints & ATH9K_INT_TIM_TIMER)

drivers/net/wireless/ath/ath9k/hw.h

@@ -479,7 +479,6 @@ struct ath_hw {
 
 	int16_t curchan_rad_index;
 	enum ath9k_int imask;
-	u32 mask_reg;
 	u32 imrs2_reg;
 	u32 txok_interrupt_mask;
 	u32 txerr_interrupt_mask;

drivers/net/wireless/ath/ath9k/mac.c

@@ -105,7 +105,7 @@ bool ath9k_hw_updatetxtriglevel(struct ath_hw *ah, bool bIncTrigLevel)
 	if (ah->tx_trig_level >= ah->config.max_txtrig_level)
 		return false;
 
-	omask = ath9k_hw_set_interrupts(ah, ah->mask_reg & ~ATH9K_INT_GLOBAL);
+	omask = ath9k_hw_set_interrupts(ah, ah->imask & ~ATH9K_INT_GLOBAL);
 
 	txcfg = REG_READ(ah, AR_TXCFG);
 	curLevel = MS(txcfg, AR_FTRIG);