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net: pxa168_eth: Use dma_wmb/rmb where appropriate 

Update the pxa168_eth driver to use the dma_rmb/wmb calls instead of the
full barriers in order to improve performance: reduced 97ns/39ns on
average in tx/rx path on Marvell BG4CT platform.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jisheng Zhang 2016-05-13 19:57:30 +08:00 committed by David S. Miller
parent 3ed687823c
commit b17d15592d
1 changed files with 4 additions and 4 deletions
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8
drivers/net/ethernet/marvell/pxa168_eth.c
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@ -342,9 +342,9 @@ static void rxq_refill(struct net_device *dev)
pep->rx_skb[used_rx_desc] = skb;
/* Return the descriptor to DMA ownership */
wmb();
dma_wmb();
p_used_rx_desc->cmd_sts = BUF_OWNED_BY_DMA | RX_EN_INT;
wmb();
dma_wmb();
/* Move the used descriptor pointer to the next descriptor */
pep->rx_used_desc_q = (used_rx_desc + 1) % pep->rx_ring_size;
@ -794,7 +794,7 @@ static int rxq_process(struct net_device *dev, int budget)
rx_used_desc = pep->rx_used_desc_q;
rx_desc = &pep->p_rx_desc_area[rx_curr_desc];
cmd_sts = rx_desc->cmd_sts;
rmb();
dma_rmb();
if (cmd_sts & (BUF_OWNED_BY_DMA))
break;
skb = pep->rx_skb[rx_curr_desc];
@ -1287,7 +1287,7 @@ static int pxa168_eth_start_xmit(struct sk_buff *skb, struct net_device *dev)
skb_tx_timestamp(skb);
wmb();
dma_wmb();
desc->cmd_sts = BUF_OWNED_BY_DMA | TX_GEN_CRC | TX_FIRST_DESC |
TX_ZERO_PADDING | TX_LAST_DESC | TX_EN_INT;
wmb();