ath9k: simplify hw reset locking

The new PCU lock is better placed so we can just contend
against that when trying to reset hardware.

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:  Ben Greear <greearb@candelatech.com>
Cc: Kyungwan Nam <kyungwan.nam@atheros.com>
Cc: stable@kernel.org
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 8 insertions, 20 deletions

diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 81fed83add7a..cb9194a5b561 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -599,7 +599,6 @@ struct ath_softc {
         struct ath_hw *sc_ah;
         void __iomem *mem;
         int irq;
-        spinlock_t sc_resetlock;
         spinlock_t sc_serial_rw;
         spinlock_t sc_pm_lock;
         struct mutex mutex;
diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c
index 1b72720b36e2..adff0da01f4c 100644
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -580,7 +580,6 @@ static int ath9k_init_softc(u16 devid, struct ath_softc *sc, u16 subsysid,
         spin_lock_init(&common->cc_lock);
 
         spin_lock_init(&sc->wiphy_lock);
-        spin_lock_init(&sc->sc_resetlock);
         spin_lock_init(&sc->sc_serial_rw);
         spin_lock_init(&sc->sc_pm_lock);
         mutex_init(&sc->mutex);
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 92ed5bb71196..341d587b686b 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -262,19 +262,15 @@ int ath_set_channel(struct ath_softc *sc, struct ieee80211_hw *hw,
                   channel->center_freq, conf_is_ht40(conf),
                   fastcc);
 
-        spin_lock_bh(&sc->sc_resetlock);
-
         r = ath9k_hw_reset(ah, hchan, caldata, fastcc);
         if (r) {
                 ath_print(common, ATH_DBG_FATAL,
                           "Unable to reset channel (%u MHz), "
                           "reset status %d\n",
                           channel->center_freq, r);
-                spin_unlock_bh(&sc->sc_resetlock);
                 spin_unlock_bh(&sc->rx.pcu_lock);
                 goto ps_restore;
         }
-        spin_unlock_bh(&sc->sc_resetlock);
 
         if (ath_startrecv(sc) != 0) {
                 ath_print(common, ATH_DBG_FATAL,
@@ -886,7 +882,6 @@ void ath_radio_enable(struct ath_softc *sc, struct ieee80211_hw *hw)
                 ah->curchan = ath_get_curchannel(sc, sc->hw);
 
         spin_lock_bh(&sc->rx.pcu_lock);
-        spin_lock_bh(&sc->sc_resetlock);
         r = ath9k_hw_reset(ah, ah->curchan, ah->caldata, false);
         if (r) {
                 ath_print(common, ATH_DBG_FATAL,
@@ -894,7 +889,6 @@ void ath_radio_enable(struct ath_softc *sc, struct ieee80211_hw *hw)
                           "reset status %d\n",
                           channel->center_freq, r);
         }
-        spin_unlock_bh(&sc->sc_resetlock);
 
         ath_update_txpow(sc);
         if (ath_startrecv(sc) != 0) {
@@ -951,7 +945,6 @@ void ath_radio_disable(struct ath_softc *sc, struct ieee80211_hw *hw)
         if (!ah->curchan)
                 ah->curchan = ath_get_curchannel(sc, hw);
 
-        spin_lock_bh(&sc->sc_resetlock);
         r = ath9k_hw_reset(ah, ah->curchan, ah->caldata, false);
         if (r) {
                 ath_print(ath9k_hw_common(sc->sc_ah), ATH_DBG_FATAL,
@@ -959,7 +952,6 @@ void ath_radio_disable(struct ath_softc *sc, struct ieee80211_hw *hw)
                           "reset status %d\n",
                           channel->center_freq, r);
         }
-        spin_unlock_bh(&sc->sc_resetlock);
 
         ath9k_hw_phy_disable(ah);
 
@@ -990,12 +982,10 @@ int ath_reset(struct ath_softc *sc, bool retry_tx)
         ath_stoprecv(sc);
         ath_flushrecv(sc);
 
-        spin_lock_bh(&sc->sc_resetlock);
         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_resetlock);
 
         if (ath_startrecv(sc) != 0)
                 ath_print(common, ATH_DBG_FATAL,
@@ -1166,18 +1156,15 @@ static int ath9k_start(struct ieee80211_hw *hw)
          * and then setup of the interrupt mask.
          */
         spin_lock_bh(&sc->rx.pcu_lock);
-        spin_lock_bh(&sc->sc_resetlock);
         r = ath9k_hw_reset(ah, init_channel, ah->caldata, false);
         if (r) {
                 ath_print(common, ATH_DBG_FATAL,
                           "Unable to reset hardware; reset status %d "
                           "(freq %u MHz)\n", r,
                           curchan->center_freq);
-                spin_unlock_bh(&sc->sc_resetlock);
                 spin_unlock_bh(&sc->rx.pcu_lock);
                 goto mutex_unlock;
         }
-        spin_unlock_bh(&sc->sc_resetlock);
 
         /*
          * This is needed only to setup initial state
@@ -1398,14 +1385,17 @@ static void ath9k_stop(struct ieee80211_hw *hw)
          * before setting the invalid flag. */
         ath9k_hw_disable_interrupts(ah);
 
-        spin_lock_bh(&sc->rx.pcu_lock);
         if (!(sc->sc_flags & SC_OP_INVALID)) {
                 ath_drain_all_txq(sc, false);
+                spin_lock_bh(&sc->rx.pcu_lock);
                 ath_stoprecv(sc);
                 ath9k_hw_phy_disable(ah);
-        } else
+                spin_unlock_bh(&sc->rx.pcu_lock);
+        } else {
+                spin_lock_bh(&sc->rx.pcu_lock);
                 sc->rx.rxlink = NULL;
-        spin_unlock_bh(&sc->rx.pcu_lock);
+                spin_unlock_bh(&sc->rx.pcu_lock);
+        }
 
         /* disable HAL and put h/w to sleep */
         ath9k_hw_disable(ah);
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index f2ade2402ce2..e662ecade398 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -1148,13 +1148,13 @@ 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_resetlock);
+                spin_lock_bh(&sc->rx.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_resetlock);
+                spin_unlock_bh(&sc->rx.pcu_lock);
         }
 
         for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {