From: Anatolij Gustschin <agust@denx.de>
To: netdev@vger.kernel.org
Cc: Wolfgang Denk <wd@denx.de>, Detlev Zundel <dzu@denx.de>,
linuxppc-dev@ozlabs.org, Anatolij Gustschin <agust@denx.de>,
"David S. Miller" <davem@davemloft.net>,
Piotr Ziecik <kosmo@semihalf.com>
Subject: [net-next-2.6 PATCH v2 3/3] fs_enet: add FEC TX buffer alignment workaround for MPC5121
Date: Wed, 17 Feb 2010 15:55:30 +0100 [thread overview]
Message-ID: <1266418530-2727-4-git-send-email-agust@denx.de> (raw)
In-Reply-To: <1266418530-2727-3-git-send-email-agust@denx.de>
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>
---
drivers/net/fs_enet/fs_enet-main.c | 44 ++++++++++++++++++++++++++++++++++++
1 files changed, 44 insertions(+), 0 deletions(-)
diff --git a/drivers/net/fs_enet/fs_enet-main.c b/drivers/net/fs_enet/fs_enet-main.c
index 4297021..166a89d 100644
--- a/drivers/net/fs_enet/fs_enet-main.c
+++ b/drivers/net/fs_enet/fs_enet-main.c
@@ -580,6 +580,37 @@ 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(ENET_RX_FRSIZE + 4);
+ if (!new_skb) {
+ 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 +619,19 @@ 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);
/*
--
1.6.3.3
next prev parent reply other threads:[~2010-02-17 14:57 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-17 14:55 [net-next-2.6 PATCH v2 0/3] Support for MPC512x FEC Anatolij Gustschin
2010-02-17 14:55 ` [net-next-2.6 PATCH v2 1/3] fs_enet: use dev_xxx instead of printk Anatolij Gustschin
2010-02-17 14:55 ` [net-next-2.6 PATCH v2 2/3] fs_enet: Add support for MPC512x to fs_enet driver Anatolij Gustschin
2010-02-17 14:55 ` Anatolij Gustschin [this message]
2010-02-17 15:13 ` [net-next-2.6 PATCH v2 3/3] fs_enet: add FEC TX buffer alignment workaround for MPC5121 Grant Likely
2010-02-17 15:17 ` Eric Dumazet
2010-02-17 21:31 ` Anatolij Gustschin
2010-02-17 22:08 ` [net-next-2.6 PATCH v3 " Anatolij Gustschin
2010-02-17 15:11 ` [net-next-2.6 PATCH v2 2/3] fs_enet: Add support for MPC512x to fs_enet driver Grant Likely
2010-02-22 11:37 ` [net-next-2.6 PATCH v2 0/3] Support for MPC512x FEC Anatolij Gustschin
2010-02-22 11:44 ` David Miller
2010-02-26 20:18 ` Anatolij Gustschin
2010-02-26 20:48 ` David Miller
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