ath9k: Revamp PCIE workarounds

* Disable L1 state ONLY when device is in D3 mode.
* Clear bit 22 of register 0x4004.
* Handle power on/off properly

Not setting the workarounds properly resulted in the
disappearance of the card in certain cases.

Signed-off-by: Vivek Natarajan <vnatarajan@atheros.com>
Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -965,7 +965,7 @@ int ath9k_hw_init(struct ath_hw *ah)
 	ath9k_hw_init_mode_regs(ah);
 
 	if (ah->is_pciexpress)
-		ath9k_hw_configpcipowersave(ah, 0);
+		ath9k_hw_configpcipowersave(ah, 0, 0);
 	else
 		ath9k_hw_disablepcie(ah);
 
@@ -3005,9 +3005,10 @@ void ath9k_ps_restore(struct ath_softc *sc)
  * Programming the SerDes must go through the same 288 bit serial shift
  * register as the other analog registers.  Hence the 9 writes.
  */
-void ath9k_hw_configpcipowersave(struct ath_hw *ah, int restore)
+void ath9k_hw_configpcipowersave(struct ath_hw *ah, int restore, int power_off)
 {
 	u8 i;
+	u32 val;
 
 	if (ah->is_pciexpress != true)
 		return;
@@ -3017,9 +3018,7 @@ void ath9k_hw_configpcipowersave(struct ath_hw *ah, int restore)
 		return;
 
 	/* Nothing to do on restore for 11N */
-	if (restore)
+	if (!restore) {
-		return;
-
 		if (AR_SREV_9280_20_OR_LATER(ah)) {
 			/*
 			 * AR9280 2.0 or later chips use SerDes values from the
@@ -3083,18 +3082,49 @@ void ath9k_hw_configpcipowersave(struct ath_hw *ah, int restore)
 
 		/* Several PCIe massages to ensure proper behaviour */
 		if (ah->config.pcie_waen) {
-		REG_WRITE(ah, AR_WA, ah->config.pcie_waen);
+			val = ah->config.pcie_waen;
+			if (!power_off)
+				val &= (~AR_WA_D3_L1_DISABLE);
 		} else {
-		if (AR_SREV_9285(ah) || AR_SREV_9271(ah) || AR_SREV_9287(ah))
+			if (AR_SREV_9285(ah) || AR_SREV_9271(ah) ||
-			REG_WRITE(ah, AR_WA, AR9285_WA_DEFAULT);
+			    AR_SREV_9287(ah)) {
+				val = AR9285_WA_DEFAULT;
+				if (!power_off)
+					val &= (~AR_WA_D3_L1_DISABLE);
+			} else if (AR_SREV_9280(ah)) {
 				/*
-		 * On AR9280 chips bit 22 of 0x4004 needs to be set to
+				 * On AR9280 chips bit 22 of 0x4004 needs to be
-		 * otherwise card may disappear.
+				 * set otherwise card may disappear.
 				 */
-		else if (AR_SREV_9280(ah))
+				val = AR9280_WA_DEFAULT;
-			REG_WRITE(ah, AR_WA, AR9280_WA_DEFAULT);
+				if (!power_off)
-		else
+					val &= (~AR_WA_D3_L1_DISABLE);
-			REG_WRITE(ah, AR_WA, AR_WA_DEFAULT);
+			} else
+				val = AR_WA_DEFAULT;
+		}
+
+		REG_WRITE(ah, AR_WA, val);
+	}
+
+	if (power_off) {
+		/*
+		 * Set PCIe workaround bits
+		 * bit 14 in WA register (disable L1) should only
+		 * be set when device enters D3 and be cleared
+		 * when device comes back to D0.
+		 */
+		if (ah->config.pcie_waen) {
+			if (ah->config.pcie_waen & AR_WA_D3_L1_DISABLE)
+				REG_SET_BIT(ah, AR_WA, AR_WA_D3_L1_DISABLE);
+		} else {
+			if (((AR_SREV_9285(ah) || AR_SREV_9271(ah) ||
+			      AR_SREV_9287(ah)) &&
+			     (AR9285_WA_DEFAULT & AR_WA_D3_L1_DISABLE)) ||
+			    (AR_SREV_9280(ah) &&
+			     (AR9280_WA_DEFAULT & AR_WA_D3_L1_DISABLE))) {
+				REG_SET_BIT(ah, AR_WA, AR_WA_D3_L1_DISABLE);
+			}
+		}
 	}
 }
 

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

@@ -650,7 +650,7 @@ void ath9k_hw_set_sta_beacon_timers(struct ath_hw *ah,
 				    const struct ath9k_beacon_state *bs);
 bool ath9k_hw_setpower(struct ath_hw *ah,
 		       enum ath9k_power_mode mode);
-void ath9k_hw_configpcipowersave(struct ath_hw *ah, int restore);
+void ath9k_hw_configpcipowersave(struct ath_hw *ah, int restore, int power_off);
 
 /* Interrupt Handling */
 bool ath9k_hw_intrpend(struct ath_hw *ah);

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

@@ -1131,7 +1131,7 @@ void ath_radio_enable(struct ath_softc *sc)
 	int r;
 
 	ath9k_ps_wakeup(sc);
-	ath9k_hw_configpcipowersave(ah, 0);
+	ath9k_hw_configpcipowersave(ah, 0, 0);
 
 	if (!ah->curchan)
 		ah->curchan = ath_get_curchannel(sc, sc->hw);
@@ -1202,7 +1202,7 @@ void ath_radio_disable(struct ath_softc *sc)
 	spin_unlock_bh(&sc->sc_resetlock);
 
 	ath9k_hw_phy_disable(ah);
-	ath9k_hw_configpcipowersave(ah, 1);
+	ath9k_hw_configpcipowersave(ah, 1, 1);
 	ath9k_ps_restore(sc);
 	ath9k_hw_setpower(ah, ATH9K_PM_FULL_SLEEP);
 }
@@ -1942,7 +1942,7 @@ static int ath9k_start(struct ieee80211_hw *hw)
 	init_channel = ath_get_curchannel(sc, hw);
 
 	/* Reset SERDES registers */
-	ath9k_hw_configpcipowersave(sc->sc_ah, 0);
+	ath9k_hw_configpcipowersave(sc->sc_ah, 0, 0);
 
 	/*
 	 * The basic interface to setting the hardware in a good
@@ -2170,7 +2170,7 @@ static void ath9k_stop(struct ieee80211_hw *hw)
 
 	/* disable HAL and put h/w to sleep */
 	ath9k_hw_disable(sc->sc_ah);
-	ath9k_hw_configpcipowersave(sc->sc_ah, 1);
+	ath9k_hw_configpcipowersave(sc->sc_ah, 1, 1);
 	ath9k_hw_setpower(sc->sc_ah, ATH9K_PM_FULL_SLEEP);
 
 	sc->sc_flags |= SC_OP_INVALID;

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

@@ -676,8 +676,9 @@
 #define AR_RC_HOSTIF         0x00000100
 
 #define AR_WA                		0x4004
+#define AR_WA_D3_L1_DISABLE		(1 << 14)
 #define AR9285_WA_DEFAULT 		0x004a05cb
-#define AR9280_WA_DEFAULT           	0x0040073f
+#define AR9280_WA_DEFAULT           	0x0040073b
 #define AR_WA_DEFAULT               	0x0000073f