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: Dai Haruki <Dai.Haruki@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
index e7e8201..3e611a6 100644
--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -854,8 +854,7 @@
priv->rx_skbuff[i] = NULL;
}
- rxbdp->status = 0;
- rxbdp->length = 0;
+ rxbdp->lstatus = 0;
rxbdp->bufPtr = 0;
rxbdp++;
@@ -976,8 +975,7 @@
/* 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 @@
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 @@
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 @@
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 @@
*/
eieio();
- txbdp->status = status;
+ txbdp->lstatus = lstatus;
txbdp = next_bd(txbdp, base, priv->tx_ring_size);
@@ -1546,20 +1541,19 @@
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;
}