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sfc: Work-around flush timeout when flushes have completed

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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 <bhutchings@solarflare.com>
This commit is contained in:
Daniel Pieczko 2012-10-02 13:36:18 +01:00 committed by Ben Hutchings
parent 876be083b6
commit 525d9e8240
2 changed files with 53 additions and 4 deletions
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1
drivers/net/ethernet/sfc/net_driver.h
View File

@ -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;
};
/**

56
drivers/net/ethernet/sfc/nic.c
View File

@ -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));
}
}
}