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Message-ID: <6ee3541ba7d14a57aea08d503bb7a61d@BLUPR03MB486.namprd03.prod.outlook.com>
Date: Thu, 20 Feb 2014 14:12:08 +0000
From: "Frank.Li@...escale.com" <Frank.Li@...escale.com>
To: "fugang.duan@...escale.com" <fugang.duan@...escale.com>,
"davem@...emloft.net" <davem@...emloft.net>
CC: "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH] net: fec: fix potential issue to avoid fec interrupt
lost and crc error
> -----Original Message-----
> From: Fugang Duan [mailto:B38611@...escale.com]
> Sent: Thursday, February 20, 2014 4:15 AM
> To: Li Frank-B20596; davem@...emloft.net
> Cc: netdev@...r.kernel.org
> Subject: [PATCH] net: fec: fix potential issue to avoid fec interrupt lost
> and crc error
>
> The current flow: Set TX BD ready, and then set "INT" and "PINS" bit to
> enable tx interrupt generation and crc checksum.
>
> There has potential issue like as:
> CPU fec uDMA
> Set tx ready bit
> uDMA start the BD transmission
> Set "INT" bit
> Set "PINS" bit
> ...
>
> Above situation cause fec tx interrupt lost and fec MAC don't do CRC checksum.
> The patch fix the potential issue.
>
> Signed-off-by: Fugang Duan <B38611@...escale.com>
Acked-by: Frank Li <Frank.li@...escale.com>
> ---
> drivers/net/ethernet/freescale/fec_main.c | 13 +++++++------
> 1 files changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c
> index 45b8b22..739608b 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -390,12 +390,6 @@ fec_enet_start_xmit(struct sk_buff *skb, struct
> net_device *ndev)
> netdev_err(ndev, "Tx DMA memory map failed\n");
> return NETDEV_TX_OK;
> }
> - /* Send it on its way. Tell FEC it's ready, interrupt when done,
> - * it's the last BD of the frame, and to put the CRC on the end.
> - */
> - status |= (BD_ENET_TX_READY | BD_ENET_TX_INTR
> - | BD_ENET_TX_LAST | BD_ENET_TX_TC);
> - bdp->cbd_sc = status;
>
> if (fep->bufdesc_ex) {
>
> @@ -417,6 +411,13 @@ fec_enet_start_xmit(struct sk_buff *skb, struct
> net_device *ndev)
> }
> }
>
> + /* Send it on its way. Tell FEC it's ready, interrupt when done,
> + * it's the last BD of the frame, and to put the CRC on the end.
> + */
> + status |= (BD_ENET_TX_READY | BD_ENET_TX_INTR
> + | BD_ENET_TX_LAST | BD_ENET_TX_TC);
> + bdp->cbd_sc = status;
> +
> bdp_pre = fec_enet_get_prevdesc(bdp, fep);
> if ((id_entry->driver_data & FEC_QUIRK_ERR006358) &&
> !(bdp_pre->cbd_sc & BD_ENET_TX_READY)) {
> --
> 1.7.2.rc3
>
--
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