Commit 5a5efed4 authored by Dai Haruki's avatar Dai Haruki Committed by David S. Miller
Browse files

gianfar: Make all BD status writes 32-bit 



Whenever we want to update the status field in a BD, we usually want to
update the length field, too.  By combining them into one 32-bit field, we
reduce the number of stores to memory shared with the controller, and we
eliminate the need for order-enforcement, as the length and "READY" bit are
now updated atomically at the same time.

Signed-off-by: default avatarDai Haruki <Dai.Haruki@freescale.com>
Signed-off-by: default avatarAndy Fleming <afleming@freescale.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 31de198b

drivers/net/gianfar.c

+15 −21
Original line number Diff line number Diff line
@@ -854,8 +854,7 @@ static void free_skb_resources(struct gfar_private *priv) 
				priv->rx_skbuff[i] = NULL;

			}



			rxbdp->status = 0;

			rxbdp->length = 0;

			rxbdp->lstatus = 0;

			rxbdp->bufPtr = 0;



			rxbdp++;
@@ -976,8 +975,7 @@ int startup_gfar(struct net_device *dev) 
	/* Initialize Transmit Descriptor Ring */

	txbdp = priv->tx_bd_base;

	for (i = 0; i < priv->tx_ring_size; i++) {

		txbdp->status = 0;

		txbdp->length = 0;

		txbdp->lstatus = 0;

		txbdp->bufPtr = 0;

		txbdp++;

	}
@@ -1216,7 +1214,7 @@ static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	struct gfar_private *priv = netdev_priv(dev);

	struct txfcb *fcb = NULL;

	struct txbd8 *txbdp, *base;

	u16 status;

	u32 lstatus;

	unsigned long flags;



	/* Update transmit stats */
@@ -1230,26 +1228,25 @@ static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	base = priv->tx_bd_base;



	/* Clear all but the WRAP status flags */

	status = txbdp->status & TXBD_WRAP;

	lstatus = txbdp->lstatus & BD_LFLAG(TXBD_WRAP);



	/* Set up checksumming */

	if (CHECKSUM_PARTIAL == skb->ip_summed) {

		fcb = gfar_add_fcb(skb);

		status |= TXBD_TOE;

		lstatus |= BD_LFLAG(TXBD_TOE);

		gfar_tx_checksum(skb, fcb);

	}



	if (priv->vlgrp && vlan_tx_tag_present(skb)) {

		if (unlikely(NULL == fcb)) {

			fcb = gfar_add_fcb(skb);

			status |= TXBD_TOE;

			lstatus |= BD_LFLAG(TXBD_TOE);

		}



		gfar_tx_vlan(skb, fcb);

	}



	/* Set buffer length and pointer */

	txbdp->length = skb->len;

	txbdp->bufPtr = dma_map_single(&dev->dev, skb->data,

			skb->len, DMA_TO_DEVICE);
@@ -1260,12 +1257,10 @@ static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	priv->skb_curtx =

	    (priv->skb_curtx + 1) & TX_RING_MOD_MASK(priv->tx_ring_size);



	/* Flag the BD as interrupt-causing */

	status |= TXBD_INTERRUPT;



	/* Flag the BD as ready to go, last in frame, and  */

	/* in need of CRC */

	status |= (TXBD_READY | TXBD_LAST | TXBD_CRC);

	/* Flag the BD as ready, interrupt-causing, last, and in need of CRC */

	lstatus |=

		BD_LFLAG(TXBD_READY | TXBD_LAST | TXBD_CRC | TXBD_INTERRUPT) |

		skb->len;



	dev->trans_start = jiffies;
@@ -1278,7 +1273,7 @@ static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	 */



	eieio();

	txbdp->status = status;

	txbdp->lstatus = lstatus;



	txbdp = next_bd(txbdp, base, priv->tx_ring_size);
@@ -1546,20 +1541,19 @@ static void gfar_new_rxbdp(struct net_device *dev, struct rxbd8 *bdp, 
		struct sk_buff *skb)

{

	struct gfar_private *priv = netdev_priv(dev);

	u32 * status_len = (u32 *)bdp;

	u16 flags;

	u32 lstatus;



	bdp->bufPtr = dma_map_single(&dev->dev, skb->data,

			priv->rx_buffer_size, DMA_FROM_DEVICE);



	flags = RXBD_EMPTY | RXBD_INTERRUPT;

	lstatus = BD_LFLAG(RXBD_EMPTY | RXBD_INTERRUPT);



	if (bdp == priv->rx_bd_base + priv->rx_ring_size - 1)

		flags |= RXBD_WRAP;

		lstatus |= BD_LFLAG(RXBD_WRAP);



	eieio();



	*status_len = (u32)flags << 16;

	bdp->lstatus = lstatus;

}

drivers/net/gianfar.h

+16 −4
Original line number Diff line number Diff line
@@ -311,6 +311,8 @@ extern const char gfar_driver_version[]; 
#define ATTRELI_EI_MASK		0x00003fff

#define ATTRELI_EI(x) (x)



#define BD_LFLAG(flags) ((flags) << 16)

#define BD_LENGTH_MASK		0x00ff



/* TxBD status field bits */

#define TXBD_READY		0x8000
@@ -374,8 +376,13 @@ extern const char gfar_driver_version[]; 


struct txbd8

{

	union {

		struct {

			u16	status;	/* Status Fields */

			u16	length;	/* Buffer length */

		};

		u32 lstatus;

	};

	u32	bufPtr;	/* Buffer Pointer */

};
@@ -390,8 +397,13 @@ struct txfcb { 


struct rxbd8

{

	union {

		struct {

			u16	status;	/* Status Fields */

			u16	length;	/* Buffer Length */

		};

		u32 lstatus;

	};

	u32	bufPtr;	/* Buffer Pointer */

};

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