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fs_enet: add FEC TX buffer alignment workaround for MPC5121 

MPC5121 FEC requeries 4-byte alignmnent for TX data buffers.
This patch is a work around that copies misaligned tx packets
to an aligned skb before sending.

Signed-off-by: John Rigby <jcrigby@gmail.com>
Signed-off-by: Piotr Ziecik <kosmo@semihalf.com>
Signed-off-by: Wolfgang Denk <wd@denx.de>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Anatolij Gustschin 2010-02-26 12:00:49 +00:00 committed by David S. Miller
parent 60ab4361ad
commit cb395eaf43
1 changed files with 47 additions and 0 deletions
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47
drivers/net/fs_enet/fs_enet-main.c
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@ -580,6 +580,40 @@ void fs_cleanup_bds(struct net_device *dev)
/**********************************************************************************/
#ifdef CONFIG_FS_ENET_MPC5121_FEC
/*
* MPC5121 FEC requeries 4-byte alignment for TX data buffer!
*/
static struct sk_buff *tx_skb_align_workaround(struct net_device *dev,
struct sk_buff *skb)
{
struct sk_buff *new_skb;
struct fs_enet_private *fep = netdev_priv(dev);
/* Alloc new skb */
new_skb = dev_alloc_skb(skb->len + 4);
if (!new_skb) {
if (net_ratelimit()) {
dev_warn(fep->dev,
"Memory squeeze, dropping tx packet.\n");
}
return NULL;
}
/* Make sure new skb is properly aligned */
skb_align(new_skb, 4);
/* Copy data to new skb ... */
skb_copy_from_linear_data(skb, new_skb->data, skb->len);
skb_put(new_skb, skb->len);
/* ... and free an old one */
dev_kfree_skb_any(skb);
return new_skb;
}
#endif
static int fs_enet_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct fs_enet_private *fep = netdev_priv(dev);
@ -588,6 +622,19 @@ static int fs_enet_start_xmit(struct sk_buff *skb, struct net_device *dev)
u16 sc;
unsigned long flags;
#ifdef CONFIG_FS_ENET_MPC5121_FEC
if (((unsigned long)skb->data) & 0x3) {
skb = tx_skb_align_workaround(dev, skb);
if (!skb) {
/*
* We have lost packet due to memory allocation error
* in tx_skb_align_workaround(). Hopefully original
* skb is still valid, so try transmit it later.
*/
return NETDEV_TX_BUSY;
}
}
#endif
spin_lock_irqsave(&fep->tx_lock, flags);
/*