From 5a5efed4817ef931f648b118aeb9222e53122d2b Mon Sep 17 00:00:00 2001 From: Dai Haruki Date: Tue, 16 Dec 2008 15:34:50 -0800 Subject: [PATCH] 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 Signed-off-by: Andy Fleming Signed-off-by: David S. Miller --- drivers/net/gianfar.c | 36 +++++++++++++++--------------------- drivers/net/gianfar.h | 20 ++++++++++++++++---- 2 files changed, 31 insertions(+), 25 deletions(-) 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 @@ 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; } diff --git a/drivers/net/gianfar.h b/drivers/net/gianfar.h index 1ebf7ac..9c8974d 100644 --- a/drivers/net/gianfar.h +++ b/drivers/net/gianfar.h @@ -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 { - u16 status; /* Status Fields */ - u16 length; /* Buffer length */ + union { + struct { + u16 status; /* Status Fields */ + u16 length; /* Buffer length */ + }; + u32 lstatus; + }; u32 bufPtr; /* Buffer Pointer */ }; @@ -390,8 +397,13 @@ struct txfcb { struct rxbd8 { - u16 status; /* Status Fields */ - u16 length; /* Buffer Length */ + union { + struct { + u16 status; /* Status Fields */ + u16 length; /* Buffer Length */ + }; + u32 lstatus; + }; u32 bufPtr; /* Buffer Pointer */ }; -- 2.7.4