ath5k: move beacon processing to a tasklet

We currently send beacons directly from the interrupt routine.  This
can hold up interrupt processing in beaconing modes and makes the
ISR somewhat more complex.  Move it to a tasklet like rx and tx.

Changes-licensed-under: 3-Clause-BSD

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 36 insertions, 29 deletions

diff --git a/drivers/net/wireless/ath5k/base.c b/drivers/net/wireless/ath5k/base.c
index 8e5620afd2f..fa6a21646bf 100644
--- a/drivers/net/wireless/ath5k/base.c
+++ b/drivers/net/wireless/ath5k/base.c
@@ -350,6 +350,7 @@ static int 	ath5k_beacon_setup(struct ath5k_softc *sc,
 static void     ath5k_beacon_send(struct ath5k_softc *sc);
 static void     ath5k_beacon_config(struct ath5k_softc *sc);
 static void     ath5k_beacon_update_timers(struct ath5k_softc *sc, u64 bc_tsf);
+static void     ath5k_tasklet_beacon(unsigned long data);
 
 static inline u64 ath5k_extend_tsf(struct ath5k_hw *ah, u32 rstamp)
 {
@@ -789,6 +790,7 @@ ath5k_attach(struct pci_dev *pdev, struct ieee80211_hw *hw)
         tasklet_init(&sc->rxtq, ath5k_tasklet_rx, (unsigned long)sc);
         tasklet_init(&sc->txtq, ath5k_tasklet_tx, (unsigned long)sc);
         tasklet_init(&sc->restq, ath5k_tasklet_reset, (unsigned long)sc);
+        tasklet_init(&sc->beacontq, ath5k_tasklet_beacon, (unsigned long)sc);
         setup_timer(&sc->calib_tim, ath5k_calibrate, (unsigned long)sc);
 
         ret = ath5k_eeprom_read_mac(ah, mac);
@@ -1700,6 +1702,35 @@ ath5k_check_ibss_tsf(struct ath5k_softc *sc, struct sk_buff *skb,
         }
 }
 
+static void ath5k_tasklet_beacon(unsigned long data)
+{
+        struct ath5k_softc *sc = (struct ath5k_softc *) data;
+
+        /*
+         * Software beacon alert--time to send a beacon.
+         *
+         * In IBSS mode we use this interrupt just to
+         * keep track of the next TBTT (target beacon
+         * transmission time) in order to detect wether
+         * automatic TSF updates happened.
+         */
+        if (sc->opmode == NL80211_IFTYPE_ADHOC) {
+                /* XXX: only if VEOL suppported */
+                u64 tsf = ath5k_hw_get_tsf64(sc->ah);
+                sc->nexttbtt += sc->bintval;
+                ATH5K_DBG(sc, ATH5K_DEBUG_BEACON,
+                                "SWBA nexttbtt: %x hw_tu: %x "
+                                "TSF: %llx\n",
+                                sc->nexttbtt,
+                                TSF_TO_TU(tsf),
+                                (unsigned long long) tsf);
+        } else {
+                spin_lock(&sc->block);
+                ath5k_beacon_send(sc);
+                spin_unlock(&sc->block);
+        }
+}
+
 static void
 ath5k_tasklet_rx(unsigned long data)
 {
@@ -2039,9 +2070,8 @@ err_unmap:
  * frame contents are done as needed and the slot time is
  * also adjusted based on current state.
  *
- * this is usually called from interrupt context (ath5k_intr())
- * but also from ath5k_beacon_config() in IBSS mode which in turn
- * can be called from a tasklet and user context
+ * This is called from software irq context (beacontq or restq
+ * tasklets) or user context from ath5k_beacon_config.
  */
 static void
 ath5k_beacon_send(struct ath5k_softc *sc)
@@ -2391,6 +2421,7 @@ ath5k_stop_hw(struct ath5k_softc *sc)
         tasklet_kill(&sc->rxtq);
         tasklet_kill(&sc->txtq);
         tasklet_kill(&sc->restq);
+        tasklet_kill(&sc->beacontq);
 
         return ret;
 }
@@ -2421,32 +2452,7 @@ ath5k_intr(int irq, void *dev_id)
                         tasklet_schedule(&sc->restq);
                 } else {
                         if (status & AR5K_INT_SWBA) {
-                                /*
-                                * Software beacon alert--time to send a beacon.
-                                * Handle beacon transmission directly; deferring
-                                * this is too slow to meet timing constraints
-                                * under load.
-                                *
-                                * In IBSS mode we use this interrupt just to
-                                * keep track of the next TBTT (target beacon
-                                * transmission time) in order to detect wether
-                                * automatic TSF updates happened.
-                                */
-                                if (sc->opmode == NL80211_IFTYPE_ADHOC) {
-                                         /* XXX: only if VEOL suppported */
-                                        u64 tsf = ath5k_hw_get_tsf64(ah);
-                                        sc->nexttbtt += sc->bintval;
-                                        ATH5K_DBG(sc, ATH5K_DEBUG_BEACON,
-                                                  "SWBA nexttbtt: %x hw_tu: %x "
-                                                  "TSF: %llx\n",
-                                                  sc->nexttbtt,
-                                                  TSF_TO_TU(tsf),
-                                                  (unsigned long long) tsf);
-                                } else {
-                                        spin_lock(&sc->block);
-                                        ath5k_beacon_send(sc);
-                                        spin_unlock(&sc->block);
-                                }
+                                tasklet_schedule(&sc->beacontq);
                         }
                         if (status & AR5K_INT_RXEOL) {
                                 /*
diff --git a/drivers/net/wireless/ath5k/base.h b/drivers/net/wireless/ath5k/base.h
index c0fb8b5c42f..20e0d14b41e 100644
--- a/drivers/net/wireless/ath5k/base.h
+++ b/drivers/net/wireless/ath5k/base.h
@@ -169,6 +169,7 @@ struct ath5k_softc {
         struct ath5k_led        tx_led;         /* tx led */
 
         spinlock_t              block;          /* protects beacon */
+        struct tasklet_struct   beacontq;       /* beacon intr tasklet */
         struct ath5k_buf        *bbuf;          /* beacon buffer */
         unsigned int            bhalq,          /* SW q for outgoing beacons */
                                 bmisscount,     /* missed beacon transmits */