Commit 6a6733f2 authored by Luis R. Rodriguez's avatar Luis R. Rodriguez Committed by John W. Linville
Browse files

ath9k: content DMA start / stop through the PCU lock 

This helps align resets / RX enable & disable / TX stop / start.
Locking around the PCU is important to ensure the hardware doesn't
get stale data when working with DMA'able data.

This is part of a series of patches which fix stopping
TX DMA completley when requested on the driver.
For more details about this issue refer to this thread:

http://marc.info/?l=linux-wireless&m=128629803703756&w=2



Tested-by: default avatarBen Greear <greearb@candelatech.com>
Cc: Kyungwan Nam <kyungwan.nam@atheros.com>
Cc: stable@kernel.org
Signed-off-by: default avatarLuis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 4bdd1e97

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

+26 −26
Original line number Diff line number Diff line
@@ -230,6 +230,8 @@ int ath_set_channel(struct ath_softc *sc, struct ieee80211_hw *hw, 


	ath9k_ps_wakeup(sc);



	spin_lock_bh(&sc->sc_pcu_lock);



	/*

	 * This is only performed if the channel settings have

	 * actually changed.
@@ -242,8 +244,6 @@ int ath_set_channel(struct ath_softc *sc, struct ieee80211_hw *hw, 
	ath9k_hw_disable_interrupts(ah);

	ath_drain_all_txq(sc, false);



	spin_lock_bh(&sc->sc_pcu_lock);



	stopped = ath_stoprecv(sc);



	/* XXX: do not flush receive queue here. We don't want
@@ -268,7 +268,6 @@ int ath_set_channel(struct ath_softc *sc, struct ieee80211_hw *hw, 
			  "Unable to reset channel (%u MHz), "

			  "reset status %d\n",

			  channel->center_freq, r);

		spin_unlock_bh(&sc->sc_pcu_lock);

		goto ps_restore;

	}
@@ -276,12 +275,9 @@ int ath_set_channel(struct ath_softc *sc, struct ieee80211_hw *hw, 
		ath_print(common, ATH_DBG_FATAL,

			  "Unable to restart recv logic\n");

		r = -EIO;

		spin_unlock_bh(&sc->sc_pcu_lock);

		goto ps_restore;

	}



	spin_unlock_bh(&sc->sc_pcu_lock);



	ath_update_txpow(sc);

	ath9k_hw_set_interrupts(ah, ah->imask);
@@ -292,6 +288,8 @@ int ath_set_channel(struct ath_softc *sc, struct ieee80211_hw *hw, 
	}



 ps_restore:

	spin_unlock_bh(&sc->sc_pcu_lock);



	ath9k_ps_restore(sc);

	return r;

}
@@ -605,6 +603,8 @@ void ath9k_tasklet(unsigned long data) 
		return;

	}



	spin_lock_bh(&sc->sc_pcu_lock);



	if (!ath9k_hw_check_alive(ah))

		ieee80211_queue_work(sc->hw, &sc->hw_check_work);
@@ -615,15 +615,12 @@ void ath9k_tasklet(unsigned long data) 
		rxmask = (ATH9K_INT_RX | ATH9K_INT_RXEOL | ATH9K_INT_RXORN);



	if (status & rxmask) {

		spin_lock_bh(&sc->sc_pcu_lock);



		/* Check for high priority Rx first */

		if ((ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) &&

		    (status & ATH9K_INT_RXHP))

			ath_rx_tasklet(sc, 0, true);



		ath_rx_tasklet(sc, 0, false);

		spin_unlock_bh(&sc->sc_pcu_lock);

	}



	if (status & ATH9K_INT_TX) {
@@ -649,6 +646,8 @@ void ath9k_tasklet(unsigned long data) 


	/* re-enable hardware interrupt */

	ath9k_hw_enable_interrupts(ah);



	spin_unlock_bh(&sc->sc_pcu_lock);

	ath9k_ps_restore(sc);

}
@@ -876,12 +875,13 @@ void ath_radio_enable(struct ath_softc *sc, struct ieee80211_hw *hw) 
	int r;



	ath9k_ps_wakeup(sc);

	spin_lock_bh(&sc->sc_pcu_lock);



	ath9k_hw_configpcipowersave(ah, 0, 0);



	if (!ah->curchan)

		ah->curchan = ath_get_curchannel(sc, sc->hw);



	spin_lock_bh(&sc->sc_pcu_lock);

	r = ath9k_hw_reset(ah, ah->curchan, ah->caldata, false);

	if (r) {

		ath_print(common, ATH_DBG_FATAL,
@@ -897,8 +897,6 @@ void ath_radio_enable(struct ath_softc *sc, struct ieee80211_hw *hw) 
		spin_unlock_bh(&sc->sc_pcu_lock);

		return;

	}

	spin_unlock_bh(&sc->sc_pcu_lock);



	if (sc->sc_flags & SC_OP_BEACONS)

		ath_beacon_config(sc, NULL);	/* restart beacons */
@@ -911,6 +909,8 @@ void ath_radio_enable(struct ath_softc *sc, struct ieee80211_hw *hw) 
	ath9k_hw_set_gpio(ah, ah->led_pin, 0);



	ieee80211_wake_queues(hw);

	spin_unlock_bh(&sc->sc_pcu_lock);



	ath9k_ps_restore(sc);

}
@@ -921,6 +921,8 @@ void ath_radio_disable(struct ath_softc *sc, struct ieee80211_hw *hw) 
	int r;



	ath9k_ps_wakeup(sc);

	spin_lock_bh(&sc->sc_pcu_lock);



	ieee80211_stop_queues(hw);



	/*
@@ -937,8 +939,6 @@ void ath_radio_disable(struct ath_softc *sc, struct ieee80211_hw *hw) 


	ath_drain_all_txq(sc, false);	/* clear pending tx frames */



	spin_lock_bh(&sc->sc_pcu_lock);



	ath_stoprecv(sc);		/* turn off frame recv */

	ath_flushrecv(sc);		/* flush recv queue */
@@ -955,10 +955,11 @@ void ath_radio_disable(struct ath_softc *sc, struct ieee80211_hw *hw) 


	ath9k_hw_phy_disable(ah);



	spin_unlock_bh(&sc->sc_pcu_lock);



	ath9k_hw_configpcipowersave(ah, 1, 1);



	spin_unlock_bh(&sc->sc_pcu_lock);

	ath9k_ps_restore(sc);



	ath9k_setpower(sc, ATH9K_PM_FULL_SLEEP);

}
@@ -972,13 +973,13 @@ int ath_reset(struct ath_softc *sc, bool retry_tx) 
	/* Stop ANI */

	del_timer_sync(&common->ani.timer);



	spin_lock_bh(&sc->sc_pcu_lock);



	ieee80211_stop_queues(hw);



	ath9k_hw_disable_interrupts(ah);

	ath_drain_all_txq(sc, retry_tx);



	spin_lock_bh(&sc->sc_pcu_lock);



	ath_stoprecv(sc);

	ath_flushrecv(sc);
@@ -991,8 +992,6 @@ int ath_reset(struct ath_softc *sc, bool retry_tx) 
		ath_print(common, ATH_DBG_FATAL,

			  "Unable to start recv logic\n");



	spin_unlock_bh(&sc->sc_pcu_lock);



	/*

	 * We may be doing a reset in response to a request

	 * that changes the channel so update any state that
@@ -1017,6 +1016,7 @@ int ath_reset(struct ath_softc *sc, bool retry_tx) 
	}



	ieee80211_wake_queues(hw);

	spin_unlock_bh(&sc->sc_pcu_lock);



	/* Start ANI */

	ath_start_ani(common);
@@ -1381,25 +1381,25 @@ static void ath9k_stop(struct ieee80211_hw *hw) 
			ath9k_btcoex_timer_pause(sc);

	}



	spin_lock_bh(&sc->sc_pcu_lock);



	/* make sure h/w will not generate any interrupt

	 * before setting the invalid flag. */

	ath9k_hw_disable_interrupts(ah);



	if (!(sc->sc_flags & SC_OP_INVALID)) {

		ath_drain_all_txq(sc, false);

		spin_lock_bh(&sc->sc_pcu_lock);

		ath_stoprecv(sc);

		ath9k_hw_phy_disable(ah);

		spin_unlock_bh(&sc->sc_pcu_lock);

	} else {

		spin_lock_bh(&sc->sc_pcu_lock);

	} else

		sc->rx.rxlink = NULL;

		spin_unlock_bh(&sc->sc_pcu_lock);

	}



	/* disable HAL and put h/w to sleep */

	ath9k_hw_disable(ah);

	ath9k_hw_configpcipowersave(ah, 1, 1);



	spin_unlock_bh(&sc->sc_pcu_lock);



	ath9k_ps_restore(sc);



	/* Finally, put the chip in FULL SLEEP mode */

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

+0 −2
Original line number Diff line number Diff line
@@ -1148,13 +1148,11 @@ void ath_drain_all_txq(struct ath_softc *sc, bool retry_tx) 
		ath_print(common, ATH_DBG_FATAL,

			  "Failed to stop TX DMA. Resetting hardware!\n");



		spin_lock_bh(&sc->sc_pcu_lock);

		r = ath9k_hw_reset(ah, sc->sc_ah->curchan, ah->caldata, false);

		if (r)

			ath_print(common, ATH_DBG_FATAL,

				  "Unable to reset hardware; reset status %d\n",

				  r);

		spin_unlock_bh(&sc->sc_pcu_lock);

	}



	for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {