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Message-Id: <1229469667-25002-11-git-send-email-afleming@freescale.com>
Date: Tue, 16 Dec 2008 17:21:03 -0600
From: Andy Fleming <afleming@...escale.com>
To: jeff@...zik.org
Cc: galak@...nel.crashing.org, netdev@...r.kernel.org,
Andy Fleming <afleming@...escale.com>,
Dai Haruki <Dai.Haruki@...escale.com>
Subject: [PATCH v2.6.29 10/14] 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@...escale.com>
Signed-off-by: Andy Fleming <afleming@...escale.com>
---
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 2c88701..27dbe5a 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);
@@ -1542,20 +1537,19 @@ 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 */
};
--
1.5.4.GIT
--
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