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Message-Id: <1238089445-28396-1-git-send-email-Joakim.Tjernlund@transmode.se>
Date: Thu, 26 Mar 2009 18:44:05 +0100
From: Joakim Tjernlund <Joakim.Tjernlund@...nsmode.se>
To: avorontsov@...mvista.com, leoli@...escale.com,
linuxppc-dev@...abs.org, netdev@...r.kernel.org
Cc: Joakim Tjernlund <Joakim.Tjernlund@...nsmode.se>
Subject: [PATCH] ucc_geth: Rework the TX logic.
The line:
if ((bd == ugeth->txBd[txQ]) && (netif_queue_stopped(dev) == 0))
break;
in ucc_geth_tx() didn not make sense to me. Rework & cleanup
this logic to something understandable.
---
Reworked the patch according to Antons comments.
drivers/net/ucc_geth.c | 66 +++++++++++++++++++++++++++--------------------
1 files changed, 38 insertions(+), 28 deletions(-)
diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index 7fc91aa..465de3a 100644
--- a/drivers/net/ucc_geth.c
+++ b/drivers/net/ucc_geth.c
@@ -161,6 +161,17 @@ static struct ucc_geth_info ugeth_primary_info = {
static struct ucc_geth_info ugeth_info[8];
+
+static inline u32 __iomem *bd2buf(u8 __iomem *bd)
+{
+ return (u32 __iomem *)(bd+4);
+}
+
+static inline u32 __iomem *bd2status(u8 __iomem *bd)
+{
+ return (u32 __iomem *)bd;
+}
+
#ifdef DEBUG
static void mem_disp(u8 *addr, int size)
{
@@ -3048,6 +3059,7 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev)
u8 __iomem *bd; /* BD pointer */
u32 bd_status;
u8 txQ = 0;
+ int tx_ind;
ugeth_vdbg("%s: IN", __func__);
@@ -3057,21 +3069,19 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev)
/* Start from the next BD that should be filled */
bd = ugeth->txBd[txQ];
- bd_status = in_be32((u32 __iomem *)bd);
+ bd_status = in_be32(bd2status(bd));
/* Save the skb pointer so we can free it later */
- ugeth->tx_skbuff[txQ][ugeth->skb_curtx[txQ]] = skb;
+ tx_ind = ugeth->skb_curtx[txQ];
+ ugeth->tx_skbuff[txQ][tx_ind] = skb;
/* Update the current skb pointer (wrapping if this was the last) */
- ugeth->skb_curtx[txQ] =
- (ugeth->skb_curtx[txQ] +
- 1) & TX_RING_MOD_MASK(ugeth->ug_info->bdRingLenTx[txQ]);
+ tx_ind = (tx_ind + 1) & TX_RING_MOD_MASK(ugeth->ug_info->bdRingLenTx[txQ]);
+ ugeth->skb_curtx[txQ] = tx_ind;
/* set up the buffer descriptor */
- out_be32(&((struct qe_bd __iomem *)bd)->buf,
- dma_map_single(&ugeth->dev->dev, skb->data,
- skb->len, DMA_TO_DEVICE));
-
- /* printk(KERN_DEBUG"skb->data is 0x%x\n",skb->data); */
+ out_be32(bd2buf(bd),
+ dma_map_single(&ugeth->dev->dev, skb->data,
+ skb->len, DMA_TO_DEVICE));
bd_status = (bd_status & T_W) | T_R | T_I | T_L | skb->len;
@@ -3088,9 +3098,9 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev)
/* If the next BD still needs to be cleaned up, then the bds
are full. We need to tell the kernel to stop sending us stuff. */
- if (bd == ugeth->confBd[txQ]) {
- if (!netif_queue_stopped(dev))
- netif_stop_queue(dev);
+
+ if (!in_be32(bd2buf(bd))) {
+ netif_stop_queue(dev);
}
ugeth->txBd[txQ] = bd;
@@ -3198,41 +3208,41 @@ static int ucc_geth_tx(struct net_device *dev, u8 txQ)
struct ucc_geth_private *ugeth = netdev_priv(dev);
u8 __iomem *bd; /* BD pointer */
u32 bd_status;
+ int tx_ind, num_freed;
bd = ugeth->confBd[txQ];
- bd_status = in_be32((u32 __iomem *)bd);
-
+ bd_status = in_be32(bd2status(bd));
+ tx_ind = ugeth->skb_dirtytx[txQ];
+ num_freed = 0;
/* Normal processing. */
while ((bd_status & T_R) == 0) {
/* BD contains already transmitted buffer. */
/* Handle the transmitted buffer and release */
/* the BD to be used with the current frame */
- if ((bd == ugeth->txBd[txQ]) && (netif_queue_stopped(dev) == 0))
- break;
+ if (bd == ugeth->txBd[txQ])
+ break; /* Queue is empty */
dev->stats.tx_packets++;
/* Free the sk buffer associated with this TxBD */
- dev_kfree_skb(ugeth->
- tx_skbuff[txQ][ugeth->skb_dirtytx[txQ]]);
- ugeth->tx_skbuff[txQ][ugeth->skb_dirtytx[txQ]] = NULL;
- ugeth->skb_dirtytx[txQ] =
- (ugeth->skb_dirtytx[txQ] +
- 1) & TX_RING_MOD_MASK(ugeth->ug_info->bdRingLenTx[txQ]);
-
- /* We freed a buffer, so now we can restart transmission */
- if (netif_queue_stopped(dev))
- netif_wake_queue(dev);
+ dev_kfree_skb(ugeth->tx_skbuff[txQ][tx_ind]);
+ ugeth->tx_skbuff[txQ][tx_ind] = NULL;
+ out_be32(bd2buf(bd), 0); /* Mark it free */
+ num_freed++;
+ tx_ind = (tx_ind + 1) & TX_RING_MOD_MASK(ugeth->ug_info->bdRingLenTx[txQ]);
/* Advance the confirmation BD pointer */
if (!(bd_status & T_W))
bd += sizeof(struct qe_bd);
else
bd = ugeth->p_tx_bd_ring[txQ];
- bd_status = in_be32((u32 __iomem *)bd);
+ bd_status = in_be32(bd2status(bd));
}
ugeth->confBd[txQ] = bd;
+ ugeth->skb_dirtytx[txQ] = tx_ind;
+ if (num_freed)
+ netif_wake_queue(dev); /* We freed some buffers, so restart transmission */
return 0;
}
--
1.6.1.3
--
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