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sfc: Use the correct maximum TX DMA ring size for SFC9100

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As part of a workaround for a hardware erratum in the SFC9100 family
(SF bug 35388), the TX_DESC_UPD_DWORD register address is also used
for communicating with the event block, and only descriptor pointer
values < 2048 are valid.

If the TX DMA ring size is increased to 4096 descriptors (which the
firmware still allows) then we may write a descriptor pointer
value >= 2048, which has entirely different and undesirable effects!

Limit the TX DMA ring size correctly when this workaround is in
effect.

Fixes: 8127d661e7 ('sfc: Add support for Solarflare SFC9100 family')
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Shradha Shah <sshah@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ben Hutchings 2014-01-23 14:35:48 +00:00 committed by David S. Miller
parent 8533ccf3e7
commit d9317aea16
2 changed files with 5 additions and 2 deletions
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3
drivers/net/ethernet/sfc/efx.h
View File

@ -66,6 +66,9 @@ void efx_schedule_slow_fill(struct efx_rx_queue *rx_queue);
#define EFX_RXQ_MIN_ENT 128U
#define EFX_TXQ_MIN_ENT(efx) (2 * efx_tx_max_skb_descs(efx))
#define EFX_TXQ_MAX_ENT(efx) (EFX_WORKAROUND_35388(efx) ? \
EFX_MAX_DMAQ_SIZE / 2 : EFX_MAX_DMAQ_SIZE)
/* Filters */
/**

4
drivers/net/ethernet/sfc/ethtool.c
View File

@ -591,7 +591,7 @@ static void efx_ethtool_get_ringparam(struct net_device *net_dev,
struct efx_nic *efx = netdev_priv(net_dev);
ring->rx_max_pending = EFX_MAX_DMAQ_SIZE;
ring->tx_max_pending = EFX_MAX_DMAQ_SIZE;
ring->tx_max_pending = EFX_TXQ_MAX_ENT(efx);
ring->rx_pending = efx->rxq_entries;
ring->tx_pending = efx->txq_entries;
}
@ -604,7 +604,7 @@ static int efx_ethtool_set_ringparam(struct net_device *net_dev,
if (ring->rx_mini_pending || ring->rx_jumbo_pending ||
ring->rx_pending > EFX_MAX_DMAQ_SIZE ||
ring->tx_pending > EFX_MAX_DMAQ_SIZE)
ring->tx_pending > EFX_TXQ_MAX_ENT(efx))
return -EINVAL;
if (ring->rx_pending < EFX_RXQ_MIN_ENT) {