On Fri, Mar 14, 2014 at 09:04:44AM -0500, Vince Bridgers wrote:
> +static int tse_start_xmit(struct sk_buff *skb, struct net_device *dev)
> +{
> + struct altera_tse_private *priv = netdev_priv(dev);
> + unsigned int txsize = priv->tx_ring_size;
> + unsigned int entry;
> + struct tse_buffer *buffer = NULL;
> + int nfrags = skb_shinfo(skb)->nr_frags;
> + unsigned int nopaged_len = skb_headlen(skb);
> + enum netdev_tx ret = NETDEV_TX_OK;
> + dma_addr_t dma_addr;
> + int txcomplete = 0;
> +
> + spin_lock_bh(&priv->tx_lock);
> +
> + if (unlikely(tse_tx_avail(priv) < nfrags + 1)) {
> + if (!netif_queue_stopped(dev)) {
> + netif_stop_queue(dev);
> + /* This is a hard error, log it. */
> + netdev_err(priv->dev,
> + "%s: Tx list full when queue awake\n",
> + __func__);
> + }
> + ret = NETDEV_TX_BUSY;
> + goto out;
> + }
> +
> + /* Map the first skb fragment */
> + entry = priv->tx_prod % txsize;
> + buffer = &priv->tx_ring[entry];
> +
> + dma_addr = dma_map_single(priv->device, skb->data, nopaged_len,
> + DMA_TO_DEVICE);
> + if (dma_mapping_error(priv->device, dma_addr)) {
> + netdev_err(priv->dev, "%s: DMA mapping error\n", __func__);
> + ret = NETDEV_TX_OK;
> + goto out;
> + }
> +
> + buffer->skb = skb;
> + buffer->dma_addr = dma_addr;
> + buffer->len = nopaged_len;
> +
> + /* Push data out of the cache hierarchy into main memory */
> + dma_sync_single_for_device(priv->device, buffer->dma_addr,
> + buffer->len, DMA_TO_DEVICE);
> +
> + txcomplete = priv->dmaops->tx_buffer(priv, buffer);
> +
> + priv->tx_prod++;
> + dev->stats.tx_bytes += skb->len;
This could use a call to skb_tx_timestamp() somewhere around here.
> +
> + if (unlikely(tse_tx_avail(priv) <= TXQUEUESTOP_THRESHHOLD)) {
> + if (netif_msg_hw(priv))
> + netdev_dbg(priv->dev, "%s: stop transmitted packets\n",
> + __func__);
> + netif_stop_queue(dev);
> + }
> +
> +out:
> + spin_unlock_bh(&priv->tx_lock);
> +
> + return ret;
> +}
Thanks,
Richard
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