[PATCH net-next 5/7] net:fec: add support for dumping transmit ring on timeout

[David Laight]

From: Of Frank Li
...
> When we timeout on transmit, it would be useful to dump the transmit
> ring, so we can see the ring state.  This can be helpful to diagnose
> the cause of transmit timeouts.
...
> +static void fec_dump(struct net_device *ndev)
> +{
> +	struct fec_enet_private *fep = netdev_priv(ndev);
> +	struct bufdesc *bdp = fep->tx_bd_base;
> +	unsigned index = 0;
> +
> +	netdev_info(ndev, "TX ring dump\n");
> +	pr_info("Nr     SC     addr       len  SKB\n");
> +
> +	do {
> +		pr_info("%3u %c%c 0x%04x 0x%08lx %4u %p\n",
> +			index,
> +			bdp == fep->cur_tx ? 'S' : ' ',
> +			bdp == fep->dirty_tx ? 'H' : ' ',
> +			bdp->cbd_sc, bdp->cbd_bufaddr, bdp->cbd_datlen,
> +			fep->tx_skbuff[index]);
> +		bdp = fec_enet_get_nextdesc(bdp, fep);
> +		index++;
> +	} while (bdp != fep->tx_bd_base);
> +}
> +

You probably want the read and write indexes as well.

	David