From 525d9e824018cd7cc8d8d44832ddcd363abfe6e1 Mon Sep 17 00:00:00 2001 From: Daniel Pieczko Date: Tue, 2 Oct 2012 13:36:18 +0100 Subject: [PATCH] sfc: Work-around flush timeout when flushes have completed We sometimes hit a "failed to flush" timeout on some TX queues, but the flushes have completed and the flush completion events seem to go missing. In this case, we can check the TX_DESC_PTR_TBL register and drain the queues if the flushes had finished. [bwh: Minor fixes to coding style] Signed-off-by: Ben Hutchings --- drivers/net/ethernet/sfc/net_driver.h | 1 + drivers/net/ethernet/sfc/nic.c | 56 ++++++++++++++++++++++++++++++++--- 2 files changed, 53 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h index 1014556..2d756c1 100644 --- a/drivers/net/ethernet/sfc/net_driver.h +++ b/drivers/net/ethernet/sfc/net_driver.h @@ -200,6 +200,7 @@ struct efx_tx_queue { /* Members shared between paths and sometimes updated */ unsigned int empty_read_count ____cacheline_aligned_in_smp; #define EFX_EMPTY_COUNT_VALID 0x80000000 + atomic_t flush_outstanding; }; /** diff --git a/drivers/net/ethernet/sfc/nic.c b/drivers/net/ethernet/sfc/nic.c index 1327f29..0ad790c 100644 --- a/drivers/net/ethernet/sfc/nic.c +++ b/drivers/net/ethernet/sfc/nic.c @@ -73,6 +73,8 @@ _EFX_CHANNEL_MAGIC(_EFX_CHANNEL_MAGIC_TX_DRAIN, \ (_tx_queue)->queue) +static void efx_magic_event(struct efx_channel *channel, u32 magic); + /************************************************************************** * * Solarstorm hardware access @@ -491,6 +493,9 @@ static void efx_flush_tx_queue(struct efx_tx_queue *tx_queue) struct efx_nic *efx = tx_queue->efx; efx_oword_t tx_flush_descq; + WARN_ON(atomic_read(&tx_queue->flush_outstanding)); + atomic_set(&tx_queue->flush_outstanding, 1); + EFX_POPULATE_OWORD_2(tx_flush_descq, FRF_AZ_TX_FLUSH_DESCQ_CMD, 1, FRF_AZ_TX_FLUSH_DESCQ, tx_queue->queue); @@ -666,6 +671,47 @@ static bool efx_flush_wake(struct efx_nic *efx) && atomic_read(&efx->rxq_flush_pending) > 0)); } +static bool efx_check_tx_flush_complete(struct efx_nic *efx) +{ + bool i = true; + efx_oword_t txd_ptr_tbl; + struct efx_channel *channel; + struct efx_tx_queue *tx_queue; + + efx_for_each_channel(channel, efx) { + efx_for_each_channel_tx_queue(tx_queue, channel) { + efx_reado_table(efx, &txd_ptr_tbl, + FR_BZ_TX_DESC_PTR_TBL, tx_queue->queue); + if (EFX_OWORD_FIELD(txd_ptr_tbl, + FRF_AZ_TX_DESCQ_FLUSH) || + EFX_OWORD_FIELD(txd_ptr_tbl, + FRF_AZ_TX_DESCQ_EN)) { + netif_dbg(efx, hw, efx->net_dev, + "flush did not complete on TXQ %d\n", + tx_queue->queue); + i = false; + } else if (atomic_cmpxchg(&tx_queue->flush_outstanding, + 1, 0)) { + /* The flush is complete, but we didn't + * receive a flush completion event + */ + netif_dbg(efx, hw, efx->net_dev, + "flush complete on TXQ %d, so drain " + "the queue\n", tx_queue->queue); + /* Don't need to increment drain_pending as it + * has already been incremented for the queues + * which did not drain + */ + efx_magic_event(channel, + EFX_CHANNEL_MAGIC_TX_DRAIN( + tx_queue)); + } + } + } + + return i; +} + /* Flush all the transmit queues, and continue flushing receive queues until * they're all flushed. Wait for the DRAIN events to be recieved so that there * are no more RX and TX events left on any channel. */ @@ -726,7 +772,8 @@ int efx_nic_flush_queues(struct efx_nic *efx) timeout); } - if (atomic_read(&efx->drain_pending)) { + if (atomic_read(&efx->drain_pending) && + !efx_check_tx_flush_complete(efx)) { netif_err(efx, hw, efx->net_dev, "failed to flush %d queues " "(rx %d+%d)\n", atomic_read(&efx->drain_pending), atomic_read(&efx->rxq_flush_outstanding), @@ -1018,9 +1065,10 @@ efx_handle_tx_flush_done(struct efx_nic *efx, efx_qword_t *event) if (qid < EFX_TXQ_TYPES * efx->n_tx_channels) { tx_queue = efx_get_tx_queue(efx, qid / EFX_TXQ_TYPES, qid % EFX_TXQ_TYPES); - - efx_magic_event(tx_queue->channel, - EFX_CHANNEL_MAGIC_TX_DRAIN(tx_queue)); + if (atomic_cmpxchg(&tx_queue->flush_outstanding, 1, 0)) { + efx_magic_event(tx_queue->channel, + EFX_CHANNEL_MAGIC_TX_DRAIN(tx_queue)); + } } } -- 2.7.4