From: John Jacques <john.jacq...@intel.com>
Make the transfer length a multiple of 64 bytes. The
number of bytes transferred will still be limited to
the pdulength. Hardware requires the transfer length
to be a multiple of 64.
Add a memory barrier after updating the descriptor in
memory but before incrementing the head pointer to
start packet transmission.
Signed-off-by: John Jacques <john.jacq...@intel.com>
---
drivers/net/ethernet/intel/axxia/nemac.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/axxia/nemac.c
b/drivers/net/ethernet/intel/axxia/nemac.c
index 4a3ab72..2eead12 100644
--- a/drivers/net/ethernet/intel/axxia/nemac.c
+++ b/drivers/net/ethernet/intel/axxia/nemac.c
@@ -109,6 +109,14 @@ static void desc_set_ctrl(struct dma_desc *desc, u32 ctrl)
static void desc_set_xferlen(struct dma_desc *desc, u32 len)
{
+ /* 'len' is increased to the nearest multiple of 64 bytes. The
+ current understaning of the hardware is that this will not
+ result in the hardware reading memory beyond 'pdulen'.
+ */
+
+ if (0 != (len % 64))
+ len += 64 - (len % 64);
+
desc->ctrl = ((desc->ctrl & ~D_XFER_MASK) |
((u64)len << D_XFER_SHIFT));
}
@@ -568,7 +576,12 @@ static int nemac_open(struct net_device *ndev)
pr_debug("[%s] (phy %s)\n",
priv->phy_dev->drv->name, dev_name(&priv->phy_dev->dev));
- nemac_set(priv, NEM_DMA_CTL, DMACTL_EN | DMACTL_FORCE_RX_ORDER);
+ nemac_clr(priv, NEM_DMA_CTL,
+ DMACTL_TX_TAIL_PTR_EN | DMACTL_RX_TAIL_PTR_EN);
+ nemac_set(priv, NEM_DMA_CTL,
+ DMACTL_EN |
+ DMACTL_RX_FORCE_ORDERING | DMACTL_TX_FORCE_ORDERING |
+ DMACTL_TX_DISABLE_PREALIGN | DMACTL_RX_DISABLE_PREALIGN);
napi_enable(&priv->napi);
phy_start(priv->phy_dev);
@@ -610,6 +623,7 @@ static netdev_tx_t nemac_xmit(struct sk_buff *skb, struct
net_device *ndev)
desc_set_pdulen(desc, skb->len);
desc_set_bufptr(desc, addr);
pr_desc("TX", desc);
+ mb(); /* Make sure the descriptor is in memory */
writel(queue_inc_head(&priv->txq), priv->reg + NEM_DMA_TXHEAD_PTR);
spin_unlock_irqrestore(&priv->txlock, flags);
ndev->trans_start = jiffies;
@@ -727,6 +741,7 @@ nemac_tx_cleanup(struct nemac_priv *priv)
dma_unmap_single(priv->dev, desc_get_bufptr(desc),
desc_get_xferlen(desc), DMA_TO_DEVICE);
dev_kfree_skb_any(skb);
+ mb();
queue_inc_tail(&priv->txq);
pr_queue("TX-DONE", &priv->txq);
++complete;
@@ -750,6 +765,7 @@ nemac_rx_packet(struct nemac_priv *priv)
desc = queue_get_tail(&priv->rxq);
if (!desc)
return -1;
+ mb();
queue_inc_tail(&priv->rxq);
dma_unmap_single(priv->dev, desc_get_bufptr(desc),
@@ -779,6 +795,7 @@ nemac_rx_packet(struct nemac_priv *priv)
if (!skb)
break;
queue_set_skb(&priv->rxq, desc, skb);
+ mb();
writel(queue_inc_head(&priv->rxq),
priv->reg + NEM_DMA_RXHEAD_PTR);
}
@@ -965,6 +982,7 @@ nemac_setup_descriptors(struct nemac_priv *priv)
skb = nemac_alloc_rx_buf(priv, desc);
queue_set_skb(&priv->rxq, desc, skb);
+ mb();
writel(queue_inc_head(&priv->rxq),
priv->reg + NEM_DMA_RXHEAD_PTR);
++i;
--
2.7.4
--
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