ath9k: fix a DMA related race condition at hw reset time

SVN-Revision: 24261

diff --git a/package/mac80211/patches/520-ath9k_reset_fix.patch b/package/mac80211/patches/520-ath9k_reset_fix.patch
new file mode 100644 (file)
index 0000000..10175f9
--- /dev/null
+++ b/package/mac80211/patches/520-ath9k_reset_fix.patch
@@ -0,0 +1,74 @@
+--- a/drivers/net/wireless/ath/ath9k/xmit.c
++++ b/drivers/net/wireless/ath/ath9k/xmit.c
+@@ -1172,7 +1172,7 @@ void ath_draintxq(struct ath_softc *sc, 
+       }
+ }
+ 
+-void ath_drain_all_txq(struct ath_softc *sc, bool retry_tx)
++bool ath_drain_all_txq(struct ath_softc *sc, bool retry_tx)
+ {
+       struct ath_hw *ah = sc->sc_ah;
+       struct ath_common *common = ath9k_hw_common(sc->sc_ah);
+@@ -1180,7 +1180,7 @@ void ath_drain_all_txq(struct ath_softc 
+       int i, npend = 0;
+ 
+       if (sc->sc_flags & SC_OP_INVALID)
+-              return;
++              return true;
+ 
+       /* Stop beacon queue */
+       ath9k_hw_stoptxdma(sc->sc_ah, sc->beacon.beaconq);
+@@ -1194,23 +1194,15 @@ void ath_drain_all_txq(struct ath_softc 
+               }
+       }
+ 
+-      if (npend) {
+-              int r;
+-
+-              ath_print(common, ATH_DBG_FATAL,
+-                        "Failed to stop TX DMA. Resetting hardware!\n");
+-
+-              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);
+-      }
++      if (npend)
++              ath_print(common, ATH_DBG_FATAL,  "Failed to stop TX DMA!\n");
+ 
+       for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
+               if (ATH_TXQ_SETUP(sc, i))
+                       ath_draintxq(sc, &sc->tx.txq[i], retry_tx);
+       }
++
++      return !npend;
+ }
+ 
+ void ath_tx_cleanupq(struct ath_softc *sc, struct ath_txq *txq)
+--- a/drivers/net/wireless/ath/ath9k/ath9k.h
++++ b/drivers/net/wireless/ath/ath9k/ath9k.h
+@@ -311,7 +311,7 @@ void ath_rx_cleanup(struct ath_softc *sc
+ int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp);
+ struct ath_txq *ath_txq_setup(struct ath_softc *sc, int qtype, int subtype);
+ void ath_tx_cleanupq(struct ath_softc *sc, struct ath_txq *txq);
+-void ath_drain_all_txq(struct ath_softc *sc, bool retry_tx);
++bool ath_drain_all_txq(struct ath_softc *sc, bool retry_tx);
+ void ath_draintxq(struct ath_softc *sc,
+                    struct ath_txq *txq, bool retry_tx);
+ void ath_tx_node_init(struct ath_softc *sc, struct ath_node *an);
+--- a/drivers/net/wireless/ath/ath9k/main.c
++++ b/drivers/net/wireless/ath/ath9k/main.c
+@@ -246,9 +246,10 @@ int ath_set_channel(struct ath_softc *sc
+        * the relevant bits of the h/w.
+        */
+       ath9k_hw_disable_interrupts(ah);
+-      ath_drain_all_txq(sc, false);
++      stopped = ath_drain_all_txq(sc, false);
+ 
+-      stopped = ath_stoprecv(sc);
++      if (!ath_stoprecv(sc))
++              stopped = false;
+ 
+       /* XXX: do not flush receive queue here. We don't want
+        * to flush data frames already in queue because of