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Commit 0d51cccc authored by Felix Fietkau's avatar Felix Fietkau Committed by John W. Linville
Browse files

ath9k: fix stopping tx dma on reset 



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: default avatarFelix Fietkau <nbd@openwrt.org>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 997941d7

drivers/net/wireless/ath/ath9k/mac.c

+28 −0
Original line number Diff line number Diff line
@@ -143,6 +143,34 @@ bool ath9k_hw_updatetxtriglevel(struct ath_hw *ah, bool bIncTrigLevel) 
}

EXPORT_SYMBOL(ath9k_hw_updatetxtriglevel);



void 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 = 0; i < 1000; i++) {

			if (i)

				udelay(5);



			if (!ath9k_hw_numtxpending(ah, q))

				break;

		}

	}



	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);

}

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 */

drivers/net/wireless/ath/ath9k/mac.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

void 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);

drivers/net/wireless/ath/ath9k/xmit.c

+6 −8
Original line number Diff line number Diff line
@@ -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)