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>
diff --git a/drivers/net/fs_enet/fs_enet-main.c b/drivers/net/fs_enet/fs_enet-main.c
index 4297021..0770e2f 100644
--- a/drivers/net/fs_enet/fs_enet-main.c
+++ b/drivers/net/fs_enet/fs_enet-main.c
@@ -580,6 +580,40 @@
/**********************************************************************************/
+#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 @@
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);
/*