From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yx0-f178.google.com (mail-yx0-f178.google.com [209.85.210.178]) by ozlabs.org (Postfix) with ESMTP id B5433B7CEA for ; Thu, 18 Feb 2010 02:14:14 +1100 (EST) Received: by yxe8 with SMTP id 8so10497173yxe.17 for ; Wed, 17 Feb 2010 07:14:13 -0800 (PST) MIME-Version: 1.0 Sender: glikely@secretlab.ca In-Reply-To: <1266418530-2727-4-git-send-email-agust@denx.de> References: <1266418530-2727-1-git-send-email-agust@denx.de> <1266418530-2727-2-git-send-email-agust@denx.de> <1266418530-2727-3-git-send-email-agust@denx.de> <1266418530-2727-4-git-send-email-agust@denx.de> From: Grant Likely Date: Wed, 17 Feb 2010 08:13:52 -0700 Message-ID: Subject: Re: [net-next-2.6 PATCH v2 3/3] fs_enet: add FEC TX buffer alignment workaround for MPC5121 To: Anatolij Gustschin Content-Type: text/plain; charset=ISO-8859-1 Cc: Wolfgang Denk , Detlev Zundel , netdev@vger.kernel.org, linuxppc-dev@ozlabs.org, "David S. Miller" , Piotr Ziecik List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Feb 17, 2010 at 7:55 AM, Anatolij Gustschin wrote: > 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 > Signed-off-by: Piotr Ziecik > Signed-off-by: Wolfgang Denk > Signed-off-by: Anatolij Gustschin Acked-by: Grant Likely > --- > =A0drivers/net/fs_enet/fs_enet-main.c | =A0 44 ++++++++++++++++++++++++++= ++++++++++ > =A01 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) > > =A0/*********************************************************************= *************/ > > +#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, > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0= =A0 =A0 =A0 =A0 =A0struct sk_buff *skb) > +{ > + =A0 =A0 =A0 struct sk_buff *new_skb; > + =A0 =A0 =A0 struct fs_enet_private *fep =3D netdev_priv(dev); > + > + =A0 =A0 =A0 /* Alloc new skb */ > + =A0 =A0 =A0 new_skb =3D dev_alloc_skb(ENET_RX_FRSIZE + 4); > + =A0 =A0 =A0 if (!new_skb) { > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 dev_warn(fep->dev, "Memory squeeze, droppin= g tx packet.\n"); > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 return NULL; > + =A0 =A0 =A0 } > + > + =A0 =A0 =A0 /* Make sure new skb is properly aligned */ > + =A0 =A0 =A0 skb_align(new_skb, 4); > + > + =A0 =A0 =A0 /* Copy data to new skb ... */ > + =A0 =A0 =A0 skb_copy_from_linear_data(skb, new_skb->data, skb->len); > + =A0 =A0 =A0 skb_put(new_skb, skb->len); > + > + =A0 =A0 =A0 /* ... and free an old one */ > + =A0 =A0 =A0 dev_kfree_skb_any(skb); > + > + =A0 =A0 =A0 return new_skb; > +} > +#endif > + > =A0static int fs_enet_start_xmit(struct sk_buff *skb, struct net_device *= dev) > =A0{ > =A0 =A0 =A0 =A0struct fs_enet_private *fep =3D netdev_priv(dev); > @@ -588,6 +619,19 @@ static int fs_enet_start_xmit(struct sk_buff *skb, s= truct net_device *dev) > =A0 =A0 =A0 =A0u16 sc; > =A0 =A0 =A0 =A0unsigned long flags; > > +#ifdef CONFIG_FS_ENET_MPC5121_FEC > + =A0 =A0 =A0 if (((unsigned long)skb->data) & 0x3) { > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 skb =3D tx_skb_align_workaround(dev, skb); > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 if (!skb) { > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 /* > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0* We have lost packet du= e to memory allocation error > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0* in tx_skb_align_workar= ound(). Hopefully original > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0* skb is still valid, so= try transmit it later. > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0*/ > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 return NETDEV_TX_BUSY; > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 } > + =A0 =A0 =A0 } > +#endif Instead of > =A0 =A0 =A0 =A0spin_lock_irqsave(&fep->tx_lock, flags); > > =A0 =A0 =A0 =A0/* > -- > 1.6.3.3 > > --=20 Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd.