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Commit 97a3a9a6 authored by Rob Herring's avatar Rob Herring Committed by David S. Miller
Browse files

net: calxedaxgmac: rework transmit ring handling 



Only generate tx interrupts on every ring size / 4 descriptors. Move the
netif_stop_queue call to the end of the xmit function rather than
checking at the beginning.

Signed-off-by: default avatarRob Herring <rob.herring@calxeda.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9169963d

drivers/net/ethernet/calxeda/xgmac.c

+12 −12
Original line number Diff line number Diff line
@@ -211,7 +211,7 @@ 
#define DMA_INTR_ENA_TIE	0x00000001	/* Transmit Interrupt */



#define DMA_INTR_NORMAL		(DMA_INTR_ENA_NIE | DMA_INTR_ENA_RIE | \

				 DMA_INTR_ENA_TUE)

				 DMA_INTR_ENA_TUE | DMA_INTR_ENA_TIE)



#define DMA_INTR_ABNORMAL	(DMA_INTR_ENA_AIE | DMA_INTR_ENA_FBE | \

				 DMA_INTR_ENA_RWE | DMA_INTR_ENA_RSE | \
@@ -374,6 +374,7 @@ struct xgmac_priv { 
	struct sk_buff **tx_skbuff;

	unsigned int tx_head;

	unsigned int tx_tail;

	int tx_irq_cnt;



	void __iomem *base;

	unsigned int dma_buf_sz;
@@ -886,7 +887,7 @@ static void xgmac_tx_complete(struct xgmac_priv *priv) 
	}



	if (dma_ring_space(priv->tx_head, priv->tx_tail, DMA_TX_RING_SZ) >

	    TX_THRESH)

	    MAX_SKB_FRAGS)

		netif_wake_queue(priv->dev);

}
@@ -1057,19 +1058,15 @@ static netdev_tx_t xgmac_xmit(struct sk_buff *skb, struct net_device *dev) 
	struct xgmac_priv *priv = netdev_priv(dev);

	unsigned int entry;

	int i;

	u32 irq_flag;

	int nfrags = skb_shinfo(skb)->nr_frags;

	struct xgmac_dma_desc *desc, *first;

	unsigned int desc_flags;

	unsigned int len;

	dma_addr_t paddr;



	if (dma_ring_space(priv->tx_head, priv->tx_tail, DMA_TX_RING_SZ) <

	    (nfrags + 1)) {

		writel(DMA_INTR_DEFAULT_MASK | DMA_INTR_ENA_TIE,

			priv->base + XGMAC_DMA_INTR_ENA);

		netif_stop_queue(dev);

		return NETDEV_TX_BUSY;

	}

	priv->tx_irq_cnt = (priv->tx_irq_cnt + 1) & (DMA_TX_RING_SZ/4 - 1);

	irq_flag = priv->tx_irq_cnt ? 0 : TXDESC_INTERRUPT;



	desc_flags = (skb->ip_summed == CHECKSUM_PARTIAL) ?

		TXDESC_CSUM_ALL : 0;
@@ -1110,9 +1107,9 @@ static netdev_tx_t xgmac_xmit(struct sk_buff *skb, struct net_device *dev) 
	/* Interrupt on completition only for the latest segment */

	if (desc != first)

		desc_set_tx_owner(desc, desc_flags |

			TXDESC_LAST_SEG | TXDESC_INTERRUPT);

			TXDESC_LAST_SEG | irq_flag);

	else

		desc_flags |= TXDESC_LAST_SEG | TXDESC_INTERRUPT;

		desc_flags |= TXDESC_LAST_SEG | irq_flag;



	/* Set owner on first desc last to avoid race condition */

	wmb();
@@ -1121,6 +1118,9 @@ static netdev_tx_t xgmac_xmit(struct sk_buff *skb, struct net_device *dev) 
	priv->tx_head = dma_ring_incr(entry, DMA_TX_RING_SZ);



	writel(1, priv->base + XGMAC_DMA_TX_POLL);

	if (dma_ring_space(priv->tx_head, priv->tx_tail, DMA_TX_RING_SZ) <

	    MAX_SKB_FRAGS)

		netif_stop_queue(dev);



	return NETDEV_TX_OK;

}
@@ -1397,7 +1397,7 @@ static irqreturn_t xgmac_interrupt(int irq, void *dev_id) 
	}



	/* TX/RX NORMAL interrupts */

	if (intr_status & (DMA_STATUS_RI | DMA_STATUS_TU)) {

	if (intr_status & (DMA_STATUS_RI | DMA_STATUS_TU | DMA_STATUS_TI)) {

		__raw_writel(DMA_INTR_ABNORMAL, priv->base + XGMAC_DMA_INTR_ENA);

		napi_schedule(&priv->napi);

	}