[PATCH 1/4] ath9k_hw: fix REG_SET_BIT and REG_CLR_BIT for multiple bits

[PATCH 1/4] ath9k_hw: fix REG_SET_BIT and REG_CLR_BIT for multiple bits

[Felix Fietkau]

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 drivers/net/wireless/ath/ath9k/hw.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/hw.h b/drivers/net/wireless/ath/ath9k/hw.h
index ef79f4c..6650fd4 100644
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -95,9 +95,9 @@
 #define REG_READ_FIELD(_a, _r, _f) \
 	(((REG_READ(_a, _r) & _f) >> _f##_S))
 #define REG_SET_BIT(_a, _r, _f) \
-	REG_WRITE(_a, _r, REG_READ(_a, _r) | _f)
+	REG_WRITE(_a, _r, REG_READ(_a, _r) | (_f))
 #define REG_CLR_BIT(_a, _r, _f) \
-	REG_WRITE(_a, _r, REG_READ(_a, _r) & ~_f)
+	REG_WRITE(_a, _r, REG_READ(_a, _r) & ~(_f))
 
 #define DO_DELAY(x) do {			\
 		if ((++(x) % 64) == 0)          \
-- 
1.7.3.2

[PATCH 2/4] ath9k: fix stopping tx dma on reset

[Felix Fietkau]

In some situations, stopping Tx DMA frequently fails, leading to messages
like this:

ath: Failed to stop TX DMA in 100 msec after killing last frame
ath: Failed to stop TX DMA!

This patch uses a few MAC features to abort DMA globally instead of iterating
over all hardware queues and attempting to stop them individually.
Not only is that faster and works with a shorter timeout, it also makes the
process much more reliable.

With this change, I can no longer trigger these messages on AR9380,
and on AR9280 they become much more rare.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 drivers/net/wireless/ath/ath9k/mac.c  |   31 +++++++++++++++++++++++++++++++
 drivers/net/wireless/ath/ath9k/mac.h  |    1 +
 drivers/net/wireless/ath/ath9k/xmit.c |   14 ++++++--------
 3 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/mac.c b/drivers/net/wireless/ath/ath9k/mac.c
index 5efc869..aa9f646 100644
--- a/drivers/net/wireless/ath/ath9k/mac.c
+++ b/drivers/net/wireless/ath/ath9k/mac.c
@@ -143,6 +143,37 @@ bool ath9k_hw_updatetxtriglevel(struct ath_hw *ah, bool bIncTrigLevel)
 }
 EXPORT_SYMBOL(ath9k_hw_updatetxtriglevel);
 
+bool ath9k_hw_abort_tx_dma(struct ath_hw *ah)
+{
+	int i, q;
+
+	REG_WRITE(ah, AR_Q_TXD, AR_Q_TXD_M);
+
+	REG_SET_BIT(ah, AR_PCU_MISC, AR_PCU_FORCE_QUIET_COLL | AR_PCU_CLEAR_VMF);
+	REG_SET_BIT(ah, AR_DIAG_SW, AR_DIAG_FORCE_CH_IDLE_HIGH);
+	REG_SET_BIT(ah, AR_D_GBL_IFS_MISC, AR_D_GBL_IFS_MISC_IGNORE_BACKOFF);
+
+	for (q = 0; q < AR_NUM_QCU; q++) {
+		for (i = 1000; i > 0; i--) {
+			if (!ath9k_hw_numtxpending(ah, q))
+				break;
+
+			udelay(5);
+		}
+	}
+	if (!i)
+		return false;
+
+	REG_CLR_BIT(ah, AR_PCU_MISC, AR_PCU_FORCE_QUIET_COLL | AR_PCU_CLEAR_VMF);
+	REG_CLR_BIT(ah, AR_DIAG_SW, AR_DIAG_FORCE_CH_IDLE_HIGH);
+	REG_CLR_BIT(ah, AR_D_GBL_IFS_MISC, AR_D_GBL_IFS_MISC_IGNORE_BACKOFF);
+
+	REG_WRITE(ah, AR_Q_TXD, 0);
+
+	return true;
+}
+EXPORT_SYMBOL(ath9k_hw_abort_tx_dma);
+
 bool ath9k_hw_stoptxdma(struct ath_hw *ah, u32 q)
 {
 #define ATH9K_TX_STOP_DMA_TIMEOUT	4000    /* usec */
diff --git a/drivers/net/wireless/ath/ath9k/mac.h b/drivers/net/wireless/ath/ath9k/mac.h
index 04d58ae..347ee5f 100644
--- a/drivers/net/wireless/ath/ath9k/mac.h
+++ b/drivers/net/wireless/ath/ath9k/mac.h
@@ -677,6 +677,7 @@ void ath9k_hw_cleartxdesc(struct ath_hw *ah, void *ds);
 u32 ath9k_hw_numtxpending(struct ath_hw *ah, u32 q);
 bool ath9k_hw_updatetxtriglevel(struct ath_hw *ah, bool bIncTrigLevel);
 bool ath9k_hw_stoptxdma(struct ath_hw *ah, u32 q);
+bool ath9k_hw_abort_tx_dma(struct ath_hw *ah);
 void ath9k_hw_gettxintrtxqs(struct ath_hw *ah, u32 *txqs);
 bool ath9k_hw_set_txq_props(struct ath_hw *ah, int q,
 			    const struct ath9k_tx_queue_info *qinfo);
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index e16136d..bb1d29e 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -1194,16 +1194,14 @@ bool ath_drain_all_txq(struct ath_softc *sc, bool retry_tx)
 	if (sc->sc_flags & SC_OP_INVALID)
 		return true;
 
-	/* Stop beacon queue */
-	ath9k_hw_stoptxdma(sc->sc_ah, sc->beacon.beaconq);
+	ath9k_hw_abort_tx_dma(ah);
 
-	/* Stop data queues */
+	/* Check if any queue remains active */
 	for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
-		if (ATH_TXQ_SETUP(sc, i)) {
-			txq = &sc->tx.txq[i];
-			ath9k_hw_stoptxdma(ah, txq->axq_qnum);
-			npend += ath9k_hw_numtxpending(ah, txq->axq_qnum);
-		}
+		if (!ATH_TXQ_SETUP(sc, i))
+			continue;
+
+		npend += ath9k_hw_numtxpending(ah, sc->tx.txq[i].axq_qnum);
 	}
 
 	if (npend)
-- 
1.7.3.2

[PATCH 3/4] ath9k: fix the .flush driver op implementation

[Felix Fietkau]

ath9k has a timeout of 60ms for the flush, but instead waiting 60 ms for
all tx activity to finish, it resets it for every single queue.

This patch simplifies the flush op and reuses ath_drain_all_txq for
flushing out pending frames if necessary.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 drivers/net/wireless/ath/ath9k/main.c |   55 +++++++++++---------------------
 1 files changed, 19 insertions(+), 36 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 2e228aa..0e9f748 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -2128,54 +2128,37 @@ static void ath9k_set_coverage_class(struct ieee80211_hw *hw, u8 coverage_class)
 
 static void ath9k_flush(struct ieee80211_hw *hw, bool drop)
 {
-#define ATH_FLUSH_TIMEOUT	60 /* ms */
 	struct ath_softc *sc = hw->priv;
-	struct ath_txq *txq = NULL;
-	struct ath_hw *ah = sc->sc_ah;
-	struct ath_common *common = ath9k_hw_common(ah);
-	int i, j, npend = 0;
+	int timeout = 60; /* ms */
+	int i, j;
 
 	mutex_lock(&sc->mutex);
 
 	cancel_delayed_work_sync(&sc->tx_complete_work);
 
-	for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
-		if (!ATH_TXQ_SETUP(sc, i))
-			continue;
-		txq = &sc->tx.txq[i];
+	if (drop)
+		timeout = 1;
 
-		if (!drop) {
-			for (j = 0; j < ATH_FLUSH_TIMEOUT; j++) {
-				if (!ath9k_has_pending_frames(sc, txq))
-					break;
-				usleep_range(1000, 2000);
-			}
-		}
+	for (j = 0; j < timeout; j++) {
+		int npend = 0;
+		for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
+			if (!ATH_TXQ_SETUP(sc, i))
+				continue;
 
-		if (drop || ath9k_has_pending_frames(sc, txq)) {
-			ath_dbg(common, ATH_DBG_QUEUE, "Drop frames from hw queue:%d\n",
-				txq->axq_qnum);
-			spin_lock_bh(&txq->axq_lock);
-			txq->txq_flush_inprogress = true;
-			spin_unlock_bh(&txq->axq_lock);
-
-			ath9k_ps_wakeup(sc);
-			ath9k_hw_stoptxdma(ah, txq->axq_qnum);
-			npend = ath9k_hw_numtxpending(ah, txq->axq_qnum);
-			ath9k_ps_restore(sc);
-			if (npend)
-				break;
-
-			ath_draintxq(sc, txq, false);
-			txq->txq_flush_inprogress = false;
+			npend += ath9k_has_pending_frames(sc, &sc->tx.txq[i]);
 		}
-	}
 
-	if (npend) {
-		ath_reset(sc, false);
-		txq->txq_flush_inprogress = false;
+		if (!npend)
+		    goto out;
+
+		usleep_range(1000, 2000);
 	}
 
+	ath9k_ps_wakeup(sc);
+	ath_drain_all_txq(sc, false);
+	ath9k_ps_restore(sc);
+
+out:
 	ieee80211_queue_delayed_work(hw, &sc->tx_complete_work, 0);
 	mutex_unlock(&sc->mutex);
 }
-- 
1.7.3.2

[PATCH 4/4] ath9k: improve reliability of beacon transmission and stuck beacon handling

[Felix Fietkau]

ath9k calls ath9k_hw_stoptxdma every time it sends a beacon, however there
is not much point in doing that if the previous beacon and mcast traffic
went out properly. On AR9380, calling that function too often can result
in an increase of stuck beacons due to differences in the handling of the
queue enable/disable functionality.

With this patch, the queue will only be explicitly stopped if the previous
data frames were not sent successfully. With the beacon code being the
only remaining user of ath9k_hw_stoptxdma, this function can be simplified
in order to remove the now pointless attempts at waiting for transmission
completion, which would never happen at this point due to the different
method of tx scheduling of the beacon queue.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 drivers/net/wireless/ath/ath9k/beacon.c |   13 +-----
 drivers/net/wireless/ath/ath9k/mac.c    |   68 +++---------------------------
 drivers/net/wireless/ath/ath9k/mac.h    |    2 +-
 3 files changed, 10 insertions(+), 73 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
index a4bdfdb..6d2a545f 100644
--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -373,6 +373,7 @@ void ath_beacon_tasklet(unsigned long data)
 			ath_dbg(common, ATH_DBG_BSTUCK,
 				"missed %u consecutive beacons\n",
 				sc->beacon.bmisscnt);
+			ath9k_hw_stop_dma_queue(ah, sc->beacon.beaconq);
 			ath9k_hw_bstuck_nfcal(ah);
 		} else if (sc->beacon.bmisscnt >= BSTUCK_THRESH) {
 			ath_dbg(common, ATH_DBG_BSTUCK,
@@ -450,16 +451,6 @@ void ath_beacon_tasklet(unsigned long data)
 		sc->beacon.updateslot = OK;
 	}
 	if (bfaddr != 0) {
-		/*
-		 * Stop any current dma and put the new frame(s) on the queue.
-		 * This should never fail since we check above that no frames
-		 * are still pending on the queue.
-		 */
-		if (!ath9k_hw_stoptxdma(ah, sc->beacon.beaconq)) {
-			ath_err(common, "beacon queue %u did not stop?\n",
-				sc->beacon.beaconq);
-		}
-
 		/* NB: cabq traffic should already be queued and primed */
 		ath9k_hw_puttxbuf(ah, sc->beacon.beaconq, bfaddr);
 		ath9k_hw_txstart(ah, sc->beacon.beaconq);
@@ -780,7 +771,7 @@ void ath9k_set_beaconing_status(struct ath_softc *sc, bool status)
 		ah->imask &= ~ATH9K_INT_SWBA;
 		ath9k_hw_set_interrupts(ah, ah->imask);
 		tasklet_kill(&sc->bcon_tasklet);
-		ath9k_hw_stoptxdma(ah, sc->beacon.beaconq);
+		ath9k_hw_stop_dma_queue(ah, sc->beacon.beaconq);
 	}
 	ath9k_ps_restore(sc);
 }
diff --git a/drivers/net/wireless/ath/ath9k/mac.c b/drivers/net/wireless/ath/ath9k/mac.c
index aa9f646..40373c5 100644
--- a/drivers/net/wireless/ath/ath9k/mac.c
+++ b/drivers/net/wireless/ath/ath9k/mac.c
@@ -174,84 +174,30 @@ bool ath9k_hw_abort_tx_dma(struct ath_hw *ah)
 }
 EXPORT_SYMBOL(ath9k_hw_abort_tx_dma);
 
-bool ath9k_hw_stoptxdma(struct ath_hw *ah, u32 q)
+bool ath9k_hw_stop_dma_queue(struct ath_hw *ah, u32 q)
 {
-#define ATH9K_TX_STOP_DMA_TIMEOUT	4000    /* usec */
+#define ATH9K_TX_STOP_DMA_TIMEOUT	1000    /* usec */
 #define ATH9K_TIME_QUANTUM		100     /* usec */
-	struct ath_common *common = ath9k_hw_common(ah);
-	struct ath9k_hw_capabilities *pCap = &ah->caps;
-	struct ath9k_tx_queue_info *qi;
-	u32 tsfLow, j, wait;
-	u32 wait_time = ATH9K_TX_STOP_DMA_TIMEOUT / ATH9K_TIME_QUANTUM;
-
-	if (q >= pCap->total_queues) {
-		ath_dbg(common, ATH_DBG_QUEUE,
-			"Stopping TX DMA, invalid queue: %u\n", q);
-		return false;
-	}
-
-	qi = &ah->txq[q];
-	if (qi->tqi_type == ATH9K_TX_QUEUE_INACTIVE) {
-		ath_dbg(common, ATH_DBG_QUEUE,
-			"Stopping TX DMA, inactive queue: %u\n", q);
-		return false;
-	}
+	int wait_time = ATH9K_TX_STOP_DMA_TIMEOUT / ATH9K_TIME_QUANTUM;
+	int wait;
 
 	REG_WRITE(ah, AR_Q_TXD, 1 << q);
 
 	for (wait = wait_time; wait != 0; wait--) {
 		if (ath9k_hw_numtxpending(ah, q) == 0)
 			break;
-		udelay(ATH9K_TIME_QUANTUM);
-	}
-
-	if (ath9k_hw_numtxpending(ah, q)) {
-		ath_dbg(common, ATH_DBG_QUEUE,
-			"%s: Num of pending TX Frames %d on Q %d\n",
-			__func__, ath9k_hw_numtxpending(ah, q), q);
-
-		for (j = 0; j < 2; j++) {
-			tsfLow = REG_READ(ah, AR_TSF_L32);
-			REG_WRITE(ah, AR_QUIET2,
-				  SM(10, AR_QUIET2_QUIET_DUR));
-			REG_WRITE(ah, AR_QUIET_PERIOD, 100);
-			REG_WRITE(ah, AR_NEXT_QUIET_TIMER, tsfLow >> 10);
-			REG_SET_BIT(ah, AR_TIMER_MODE,
-				       AR_QUIET_TIMER_EN);
-
-			if ((REG_READ(ah, AR_TSF_L32) >> 10) == (tsfLow >> 10))
-				break;
-
-			ath_dbg(common, ATH_DBG_QUEUE,
-				"TSF has moved while trying to set quiet time TSF: 0x%08x\n",
-				tsfLow);
-		}
-
-		REG_SET_BIT(ah, AR_DIAG_SW, AR_DIAG_FORCE_CH_IDLE_HIGH);
 
-		udelay(200);
-		REG_CLR_BIT(ah, AR_TIMER_MODE, AR_QUIET_TIMER_EN);
-
-		wait = wait_time;
-		while (ath9k_hw_numtxpending(ah, q)) {
-			if ((--wait) == 0) {
-				ath_err(common,
-					"Failed to stop TX DMA in 100 msec after killing last frame\n");
-				break;
-			}
-			udelay(ATH9K_TIME_QUANTUM);
-		}
-
-		REG_CLR_BIT(ah, AR_DIAG_SW, AR_DIAG_FORCE_CH_IDLE_HIGH);
+		udelay(ATH9K_TIME_QUANTUM);
 	}
 
 	REG_WRITE(ah, AR_Q_TXD, 0);
+
 	return wait != 0;
 
 #undef ATH9K_TX_STOP_DMA_TIMEOUT
 #undef ATH9K_TIME_QUANTUM
 }
-EXPORT_SYMBOL(ath9k_hw_stoptxdma);
+EXPORT_SYMBOL(ath9k_hw_stop_dma_queue);
 
 void ath9k_hw_gettxintrtxqs(struct ath_hw *ah, u32 *txqs)
 {
diff --git a/drivers/net/wireless/ath/ath9k/mac.h b/drivers/net/wireless/ath/ath9k/mac.h
index 347ee5f..bf8944a 100644
--- a/drivers/net/wireless/ath/ath9k/mac.h
+++ b/drivers/net/wireless/ath/ath9k/mac.h
@@ -676,7 +676,7 @@ void ath9k_hw_txstart(struct ath_hw *ah, u32 q);
 void ath9k_hw_cleartxdesc(struct ath_hw *ah, void *ds);
 u32 ath9k_hw_numtxpending(struct ath_hw *ah, u32 q);
 bool ath9k_hw_updatetxtriglevel(struct ath_hw *ah, bool bIncTrigLevel);
-bool ath9k_hw_stoptxdma(struct ath_hw *ah, u32 q);
+bool ath9k_hw_stop_dma_queue(struct ath_hw *ah, u32 q);
 bool ath9k_hw_abort_tx_dma(struct ath_hw *ah);
 void ath9k_hw_gettxintrtxqs(struct ath_hw *ah, u32 *txqs);
 bool ath9k_hw_set_txq_props(struct ath_hw *ah, int q,
-- 
1.7.3.2

Re: [PATCH 4/4] ath9k: improve reliability of beacon transmission and stuck beacon handling

[Vasanthakumar Thiagarajan]

On Thu, Mar 10, 2011 at 06:05:03AM +0530, Felix Fietkau wrote:
> ath9k calls ath9k_hw_stoptxdma every time it sends a beacon, however there
> is not much point in doing that if the previous beacon and mcast traffic
> went out properly. On AR9380, calling that function too often can result
> in an increase of stuck beacons due to differences in the handling of the
> queue enable/disable functionality.
> 
> With this patch, the queue will only be explicitly stopped if the previous
> data frames were not sent successfully. With the beacon code being the
> only remaining user of ath9k_hw_stoptxdma, this function can be simplified
> in order to remove the now pointless attempts at waiting for transmission
> completion, which would never happen at this point due to the different
> method of tx scheduling of the beacon queue.

Thanks. Can this patch be split into two, one which possibly fixes btsuck
(a stable fix) and the other one which is a cleanup?.

Vasanth

Re: [PATCH 4/4] ath9k: improve reliability of beacon transmission and stuck beacon handling

[Felix Fietkau]

On 2011-03-10 10:46 AM, Vasanthakumar Thiagarajan wrote:
> On Thu, Mar 10, 2011 at 06:05:03AM +0530, Felix Fietkau wrote:
>> ath9k calls ath9k_hw_stoptxdma every time it sends a beacon, however there
>> is not much point in doing that if the previous beacon and mcast traffic
>> went out properly. On AR9380, calling that function too often can result
>> in an increase of stuck beacons due to differences in the handling of the
>> queue enable/disable functionality.
>> 
>> With this patch, the queue will only be explicitly stopped if the previous
>> data frames were not sent successfully. With the beacon code being the
>> only remaining user of ath9k_hw_stoptxdma, this function can be simplified
>> in order to remove the now pointless attempts at waiting for transmission
>> completion, which would never happen at this point due to the different
>> method of tx scheduling of the beacon queue.
> 
> Thanks. Can this patch be split into two, one which possibly fixes btsuck
> (a stable fix) and the other one which is a cleanup?.
OK. I'll split it up, but won't propose it for stable yet, I want to see
how well it works for users first.

Thanks for the review of those patches.

- Felix

Re: [PATCH 4/4] ath9k: improve reliability of beacon transmission and stuck beacon handling

[Felix Fietkau]

On 2011-03-10 2:04 PM, Felix Fietkau wrote:
> On 2011-03-10 10:46 AM, Vasanthakumar Thiagarajan wrote:
>> On Thu, Mar 10, 2011 at 06:05:03AM +0530, Felix Fietkau wrote:
>>> ath9k calls ath9k_hw_stoptxdma every time it sends a beacon, however there
>>> is not much point in doing that if the previous beacon and mcast traffic
>>> went out properly. On AR9380, calling that function too often can result
>>> in an increase of stuck beacons due to differences in the handling of the
>>> queue enable/disable functionality.
>>> 
>>> With this patch, the queue will only be explicitly stopped if the previous
>>> data frames were not sent successfully. With the beacon code being the
>>> only remaining user of ath9k_hw_stoptxdma, this function can be simplified
>>> in order to remove the now pointless attempts at waiting for transmission
>>> completion, which would never happen at this point due to the different
>>> method of tx scheduling of the beacon queue.
>> 
>> Thanks. Can this patch be split into two, one which possibly fixes btsuck
>> (a stable fix) and the other one which is a cleanup?.
> OK. I'll split it up, but won't propose it for stable yet, I want to see
> how well it works for users first.
Actually, now that I think about it, it can't easily be split up without
introducing potential side-effects. The unmodified ath9k_hw_stoptxdma
should not be called when a beacon is stuck, because then it will hit
the code path that tries to kill pending frames by setting various flags
and waiting for a while, which is absolutely counterproductive when
being done to the beacon queue.
I think it's better to leave the patch as a whole, the changes to
ath9k_hw_stoptxdma do not fix anything without the changes to beacon.c.

- Felix

Re: [PATCH 3/4] ath9k: fix the .flush driver op implementation

[Vasanthakumar Thiagarajan]

On Thu, Mar 10, 2011 at 06:05:02AM +0530, Felix Fietkau wrote:
> ath9k has a timeout of 60ms for the flush, but instead waiting 60 ms for
> all tx activity to finish, it resets it for every single queue.

No, it does not do reset for every queue.

> +	for (j = 0; j < timeout; j++) {
> +		int npend = 0;
> +		for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
> +			if (!ATH_TXQ_SETUP(sc, i))
> +				continue;
>  
> -		if (drop || ath9k_has_pending_frames(sc, txq)) {
> -			ath_dbg(common, ATH_DBG_QUEUE, "Drop frames from hw queue:%d\n",
> -				txq->axq_qnum);
> -			spin_lock_bh(&txq->axq_lock);
> -			txq->txq_flush_inprogress = true;
> -			spin_unlock_bh(&txq->axq_lock);
> -
> -			ath9k_ps_wakeup(sc);
> -			ath9k_hw_stoptxdma(ah, txq->axq_qnum);
> -			npend = ath9k_hw_numtxpending(ah, txq->axq_qnum);
> -			ath9k_ps_restore(sc);
> -			if (npend)
> -				break;
> -
> -			ath_draintxq(sc, txq, false);
> -			txq->txq_flush_inprogress = false;
> +			npend += ath9k_has_pending_frames(sc, &sc->tx.txq[i]);
>  		}
> -	}
>  
> -	if (npend) {
> -		ath_reset(sc, false);
> -		txq->txq_flush_inprogress = false;
> +		if (!npend)
> +		    goto out;
> +
> +		usleep_range(1000, 2000);

Existing flush gives about 60ms for every q, that is reasonable
time, but this 60ms for all the queues is too small. This flush
is also called before sending null func in PS, so reset after
hw queue stuck is necessary to find the hang early on.
The usage of txq_flush_inprogress needs to be removed in other
places in xmit.

Vasanth

Re: [PATCH 3/4] ath9k: fix the .flush driver op implementation

[Felix Fietkau]

On 2011-03-10 10:25 AM, Vasanthakumar Thiagarajan wrote:
> On Thu, Mar 10, 2011 at 06:05:02AM +0530, Felix Fietkau wrote:
>> ath9k has a timeout of 60ms for the flush, but instead waiting 60 ms for
>> all tx activity to finish, it resets it for every single queue.
> 
> No, it does not do reset for every queue.
You're right, I got confused by the diff and my recollection of an old
version of the flush op ;)

>> +	for (j = 0; j < timeout; j++) {
>> +		int npend = 0;
>> +		for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
>> +			if (!ATH_TXQ_SETUP(sc, i))
>> +				continue;
>>  
>> -		if (drop || ath9k_has_pending_frames(sc, txq)) {
>> -			ath_dbg(common, ATH_DBG_QUEUE, "Drop frames from hw queue:%d\n",
>> -				txq->axq_qnum);
>> -			spin_lock_bh(&txq->axq_lock);
>> -			txq->txq_flush_inprogress = true;
>> -			spin_unlock_bh(&txq->axq_lock);
>> -
>> -			ath9k_ps_wakeup(sc);
>> -			ath9k_hw_stoptxdma(ah, txq->axq_qnum);
>> -			npend = ath9k_hw_numtxpending(ah, txq->axq_qnum);
>> -			ath9k_ps_restore(sc);
>> -			if (npend)
>> -				break;
>> -
>> -			ath_draintxq(sc, txq, false);
>> -			txq->txq_flush_inprogress = false;
>> +			npend += ath9k_has_pending_frames(sc, &sc->tx.txq[i]);
>>  		}
>> -	}
>>  
>> -	if (npend) {
>> -		ath_reset(sc, false);
>> -		txq->txq_flush_inprogress = false;
>> +		if (!npend)
>> +		    goto out;
>> +
>> +		usleep_range(1000, 2000);
> 
> Existing flush gives about 60ms for every q, that is reasonable
> time, but this 60ms for all the queues is too small. This flush
> is also called before sending null func in PS, so reset after
> hw queue stuck is necessary to find the hang early on.
So maybe we should set it to something like 200ms for all? Anything more
than that seems a bit excessive.
I intend to add some more restrictions for the queue lengths soon, then
we can reduce this timeout even further.

> The usage of txq_flush_inprogress needs to be removed in other
> places in xmit.
OK

- Felix

Re: [PATCH 2/4] ath9k: fix stopping tx dma on reset

[Vasanthakumar Thiagarajan]

On Thu, Mar 10, 2011 at 06:05:01AM +0530, Felix Fietkau wrote:
> +bool ath9k_hw_abort_tx_dma(struct ath_hw *ah)
> +{
> +	int i, q;
> +
> +	REG_WRITE(ah, AR_Q_TXD, AR_Q_TXD_M);
> +
> +	REG_SET_BIT(ah, AR_PCU_MISC, AR_PCU_FORCE_QUIET_COLL | AR_PCU_CLEAR_VMF);
> +	REG_SET_BIT(ah, AR_DIAG_SW, AR_DIAG_FORCE_CH_IDLE_HIGH);
> +	REG_SET_BIT(ah, AR_D_GBL_IFS_MISC, AR_D_GBL_IFS_MISC_IGNORE_BACKOFF);
> +
> +	for (q = 0; q < AR_NUM_QCU; q++) {
> +		for (i = 1000; i > 0; i--) {
> +			if (!ath9k_hw_numtxpending(ah, q))
> +				break;
> +
> +			udelay(5);
> +		}
> +	}
> +	if (!i)
> +		return false;

Here the assumption looks like a reset would follow to configure
those registers back, may be some comment will be useful.

> diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
> index e16136d..bb1d29e 100644
> --- a/drivers/net/wireless/ath/ath9k/xmit.c
> +++ b/drivers/net/wireless/ath/ath9k/xmit.c
> @@ -1194,16 +1194,14 @@ bool ath_drain_all_txq(struct ath_softc *sc, bool retry_tx)
>  	if (sc->sc_flags & SC_OP_INVALID)
>  		return true;
>  
> -	/* Stop beacon queue */
> -	ath9k_hw_stoptxdma(sc->sc_ah, sc->beacon.beaconq);
> +	ath9k_hw_abort_tx_dma(ah);
>  
> -	/* Stop data queues */
> +	/* Check if any queue remains active */
>  	for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
> -		if (ATH_TXQ_SETUP(sc, i)) {
> -			txq = &sc->tx.txq[i];
> -			ath9k_hw_stoptxdma(ah, txq->axq_qnum);
> -			npend += ath9k_hw_numtxpending(ah, txq->axq_qnum);
> -		}
> +		if (!ATH_TXQ_SETUP(sc, i))
> +			continue;
> +
> +		npend += ath9k_hw_numtxpending(ah, sc->tx.txq[i].axq_qnum);

This can be moved to ath9k_hw_abort_tx_dma() and make it return
npend as the current return value is unused anyway.

Vasanth

Re: [PATCH 2/4] ath9k: fix stopping tx dma on reset

[Vasanthakumar Thiagarajan]

On Thu, Mar 10, 2011 at 02:28:47PM +0530, Vasanthakumar Thiagarajan wrote:
> On Thu, Mar 10, 2011 at 06:05:01AM +0530, Felix Fietkau wrote:
> > +bool ath9k_hw_abort_tx_dma(struct ath_hw *ah)
> > +{
> > +	int i, q;
> > +
> > +	REG_WRITE(ah, AR_Q_TXD, AR_Q_TXD_M);
> > +
> > +	REG_SET_BIT(ah, AR_PCU_MISC, AR_PCU_FORCE_QUIET_COLL | AR_PCU_CLEAR_VMF);
> > +	REG_SET_BIT(ah, AR_DIAG_SW, AR_DIAG_FORCE_CH_IDLE_HIGH);
> > +	REG_SET_BIT(ah, AR_D_GBL_IFS_MISC, AR_D_GBL_IFS_MISC_IGNORE_BACKOFF);
> > +
> > +	for (q = 0; q < AR_NUM_QCU; q++) {
> > +		for (i = 1000; i > 0; i--) {
> > +			if (!ath9k_hw_numtxpending(ah, q))
> > +				break;
> > +
> > +			udelay(5);
> > +		}
> > +	}
> > +	if (!i)
> > +		return false;
> 
> Here the assumption looks like a reset would follow to configure
> those registers back, may be some comment will be useful.
> 

Also a hw reset is not guaranteed to follow this,
call of ath_drain_all_txq() in .flush(), for ex.

Vasanth

Re: [PATCH 2/4] ath9k: fix stopping tx dma on reset

[Felix Fietkau]

On 2011-03-10 9:58 AM, Vasanthakumar Thiagarajan wrote:
> On Thu, Mar 10, 2011 at 06:05:01AM +0530, Felix Fietkau wrote:
>> +bool ath9k_hw_abort_tx_dma(struct ath_hw *ah)
>> +{
>> +	int i, q;
>> +
>> +	REG_WRITE(ah, AR_Q_TXD, AR_Q_TXD_M);
>> +
>> +	REG_SET_BIT(ah, AR_PCU_MISC, AR_PCU_FORCE_QUIET_COLL | AR_PCU_CLEAR_VMF);
>> +	REG_SET_BIT(ah, AR_DIAG_SW, AR_DIAG_FORCE_CH_IDLE_HIGH);
>> +	REG_SET_BIT(ah, AR_D_GBL_IFS_MISC, AR_D_GBL_IFS_MISC_IGNORE_BACKOFF);
>> +
>> +	for (q = 0; q < AR_NUM_QCU; q++) {
>> +		for (i = 1000; i > 0; i--) {
>> +			if (!ath9k_hw_numtxpending(ah, q))
>> +				break;
>> +
>> +			udelay(5);
>> +		}
>> +	}
>> +	if (!i)
>> +		return false;
> 
> Here the assumption looks like a reset would follow to configure
> those registers back, may be some comment will be useful.
> 
>> diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
>> index e16136d..bb1d29e 100644
>> --- a/drivers/net/wireless/ath/ath9k/xmit.c
>> +++ b/drivers/net/wireless/ath/ath9k/xmit.c
>> @@ -1194,16 +1194,14 @@ bool ath_drain_all_txq(struct ath_softc *sc, bool retry_tx)
>>  	if (sc->sc_flags & SC_OP_INVALID)
>>  		return true;
>>  
>> -	/* Stop beacon queue */
>> -	ath9k_hw_stoptxdma(sc->sc_ah, sc->beacon.beaconq);
>> +	ath9k_hw_abort_tx_dma(ah);
>>  
>> -	/* Stop data queues */
>> +	/* Check if any queue remains active */
>>  	for (i = 0; i < ATH9K_NUM_TX_QUEUES; i++) {
>> -		if (ATH_TXQ_SETUP(sc, i)) {
>> -			txq = &sc->tx.txq[i];
>> -			ath9k_hw_stoptxdma(ah, txq->axq_qnum);
>> -			npend += ath9k_hw_numtxpending(ah, txq->axq_qnum);
>> -		}
>> +		if (!ATH_TXQ_SETUP(sc, i))
>> +			continue;
>> +
>> +		npend += ath9k_hw_numtxpending(ah, sc->tx.txq[i].axq_qnum);
> 
> This can be moved to ath9k_hw_abort_tx_dma() and make it return
> npend as the current return value is unused anyway.
I think I'll drop the return code of ath9k_hw_abort_tx_dma. Since it
checks the queues individually, queues that hit a timeout at first might
recover later, so it would be useful if the caller checks them properly
after the abort has been issued completely.

- Felix