ath5k: Add watchdog for stuck TX queues

Since we do not know any better solution to the problem that TX queues can get
stuck, this adds a timer-based watchdog, which will check for stuck queues and
reset the hardware if necessary.

Ported from ath9k commit 164ace38536849966ffa377b1b1132993a5a375d.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 56 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath5k/ath5k.h b/drivers/net/wireless/ath/ath5k/ath5k.h
index 50209aed0ed2..9475b2157f2d 100644
--- a/drivers/net/wireless/ath/ath5k/ath5k.h
+++ b/drivers/net/wireless/ath/ath5k/ath5k.h
@@ -206,6 +206,8 @@
 #define ATH5K_TUNE_CALIBRATION_INTERVAL_ANI     1000    /* 1 sec */
 #define ATH5K_TUNE_CALIBRATION_INTERVAL_NF      60000   /* 60 sec */
 
+#define ATH5K_TX_COMPLETE_POLL_INT              3000    /* 3 sec */
+
 #define AR5K_INIT_CARR_SENSE_EN                 1
 
 /*Swap RX/TX Descriptor for big endian archs*/
diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c
index 81f4b567c6f2..afedfeba13dd 100644
--- a/drivers/net/wireless/ath/ath5k/base.c
+++ b/drivers/net/wireless/ath/ath5k/base.c
@@ -891,6 +891,7 @@ ath5k_txq_setup(struct ath5k_softc *sc,
                 spin_lock_init(&txq->lock);
                 txq->setup = true;
                 txq->txq_len = 0;
+                txq->txq_poll_mark = false;
         }
         return &sc->txqs[qnum];
 }
@@ -989,6 +990,7 @@ ath5k_txq_drainq(struct ath5k_softc *sc, struct ath5k_txq *txq)
                 spin_unlock_bh(&sc->txbuflock);
         }
         txq->link = NULL;
+        txq->txq_poll_mark = false;
         spin_unlock_bh(&txq->lock);
 }
 
@@ -1616,6 +1618,8 @@ ath5k_tx_processq(struct ath5k_softc *sc, struct ath5k_txq *txq)
                 sc->txbuf_len++;
                 txq->txq_len--;
                 spin_unlock(&sc->txbuflock);
+
+                txq->txq_poll_mark = false;
         }
         if (likely(list_empty(&txq->q)))
                 txq->link = NULL;
@@ -2170,6 +2174,46 @@ ath5k_tasklet_ani(unsigned long data)
 }
 
 
+static void
+ath5k_tx_complete_poll_work(struct work_struct *work)
+{
+        struct ath5k_softc *sc = container_of(work, struct ath5k_softc,
+                        tx_complete_work.work);
+        struct ath5k_txq *txq;
+        int i;
+        bool needreset = false;
+
+        for (i = 0; i < ARRAY_SIZE(sc->txqs); i++) {
+                if (sc->txqs[i].setup) {
+                        txq = &sc->txqs[i];
+                        spin_lock_bh(&txq->lock);
+                        if (txq->txq_len > 0) {
+                                if (txq->txq_poll_mark) {
+                                        ATH5K_DBG(sc, ATH5K_DEBUG_XMIT,
+                                                  "TX queue stuck %d\n",
+                                                  txq->qnum);
+                                        needreset = true;
+                                        spin_unlock_bh(&txq->lock);
+                                        break;
+                                } else {
+                                        txq->txq_poll_mark = true;
+                                }
+                        }
+                        spin_unlock_bh(&txq->lock);
+                }
+        }
+
+        if (needreset) {
+                ATH5K_DBG(sc, ATH5K_DEBUG_RESET,
+                          "TX queues stuck, resetting\n");
+                ath5k_reset(sc, sc->curchan);
+        }
+
+        ieee80211_queue_delayed_work(sc->hw, &sc->tx_complete_work,
+                msecs_to_jiffies(ATH5K_TX_COMPLETE_POLL_INT));
+}
+
+
 /*************************\
 * Initialization routines *
 \*************************/
@@ -2261,6 +2305,10 @@ ath5k_init(struct ath5k_softc *sc)
 done:
         mmiowb();
         mutex_unlock(&sc->lock);
+
+        ieee80211_queue_delayed_work(sc->hw, &sc->tx_complete_work,
+                        msecs_to_jiffies(ATH5K_TX_COMPLETE_POLL_INT));
+
         return ret;
 }
 
@@ -2319,6 +2367,8 @@ ath5k_stop_hw(struct ath5k_softc *sc)
 
         stop_tasklets(sc);
 
+        cancel_delayed_work_sync(&sc->tx_complete_work);
+
         ath5k_rfkill_hw_stop(sc->ah);
 
         return ret;
@@ -2505,6 +2555,7 @@ ath5k_attach(struct pci_dev *pdev, struct ieee80211_hw *hw)
         tasklet_init(&sc->ani_tasklet, ath5k_tasklet_ani, (unsigned long)sc);
 
         INIT_WORK(&sc->reset_work, ath5k_reset_work);
+        INIT_DELAYED_WORK(&sc->tx_complete_work, ath5k_tx_complete_poll_work);
 
         ret = ath5k_eeprom_read_mac(ah, mac);
         if (ret) {
diff --git a/drivers/net/wireless/ath/ath5k/base.h b/drivers/net/wireless/ath/ath5k/base.h
index 5e2366d3db09..d8e2674aec71 100644
--- a/drivers/net/wireless/ath/ath5k/base.h
+++ b/drivers/net/wireless/ath/ath5k/base.h
@@ -87,6 +87,7 @@ struct ath5k_txq {
         spinlock_t              lock;   /* lock on q and link */
         bool                    setup;
         int                     txq_len; /* number of queued buffers */
+        bool                    txq_poll_mark;
 };
 
 #define ATH5K_LED_MAX_NAME_LEN 31
@@ -233,6 +234,8 @@ struct ath5k_softc {
 
         struct ath5k_ani_state  ani_state;
         struct tasklet_struct   ani_tasklet;    /* ANI calibration */
+
+        struct delayed_work     tx_complete_work;
 };
 
 #define ath5k_hw_hasbssidmask(_ah) \