From: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit d9317aea16ecec7694271ef11fb7791a0f0d9cc5 upstream.
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: 8127d661e77f ('sfc: Add support for Solarflare SFC9100 family')
Signed-off-by: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>
Signed-off-by: Shradha Shah <sshah@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/net/ethernet/sfc/efx.h | 3 +++
drivers/net/ethernet/sfc/ethtool.c | 4 ++--
2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/sfc/efx.h b/drivers/net/ethernet/sfc/efx.h
index 34d00f5771fe..b6b601cebb9e 100644
--- a/drivers/net/ethernet/sfc/efx.h
+++ b/drivers/net/ethernet/sfc/efx.h
@@ -67,6 +67,9 @@ extern 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 */
/**
diff --git a/drivers/net/ethernet/sfc/ethtool.c b/drivers/net/ethernet/sfc/ethtool.c
index 5b471cf5c323..3b2356bc6fba 100644
--- a/drivers/net/ethernet/sfc/ethtool.c
+++ b/drivers/net/ethernet/sfc/ethtool.c
@@ -582,7 +582,7 @@ 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;
}
@@ -595,7 +595,7 @@ 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) {
--
1.9.1
--
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