On Fri, 1 Mar 2019 17:47:24 +0000
Ioana Ciornei <ioana.cior...@nxp.com> wrote:
> +static int dpaa2_eth_xdp_xmit_frame(struct net_device *net_dev,
> + struct xdp_frame *xdpf)
> +{
> + struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
> + struct device *dev = net_dev->dev.parent;
> + struct rtnl_link_stats64 *percpu_stats;
> + struct dpaa2_eth_drv_stats *percpu_extras;
> + unsigned int needed_headroom;
> + struct dpaa2_eth_swa *swa;
> + struct dpaa2_eth_fq *fq;
> + struct dpaa2_fd fd;
> + void *buffer_start, *aligned_start;
> + dma_addr_t addr;
> + int err, i;
> +
> + /* We require a minimum headroom to be able to transmit the frame.
> + * Otherwise return an error and let the original net_device handle it
> + */
> + needed_headroom = dpaa2_eth_needed_headroom(priv, NULL);
> + if (xdpf->headroom < needed_headroom)
> + return -EINVAL;
> +
> + percpu_stats = this_cpu_ptr(priv->percpu_stats);
> + percpu_extras = this_cpu_ptr(priv->percpu_extras);
> +
> + /* Setup the FD fields */
> + memset(&fd, 0, sizeof(fd));
> +
> + /* Align FD address, if possible */
> + buffer_start = xdpf->data - needed_headroom;
> + aligned_start = PTR_ALIGN(buffer_start - DPAA2_ETH_TX_BUF_ALIGN,
> + DPAA2_ETH_TX_BUF_ALIGN);
> + if (aligned_start >= xdpf->data - xdpf->headroom)
> + buffer_start = aligned_start;
> +
> + swa = (struct dpaa2_eth_swa *)buffer_start;
> + /* fill in necessary fields here */
> + swa->type = DPAA2_ETH_SWA_XDP;
> + swa->xdp.dma_size = xdpf->data + xdpf->len - buffer_start;
> + swa->xdp.xdpf = xdpf;
> +
> + addr = dma_map_single(dev, buffer_start,
> + swa->xdp.dma_size,
> + DMA_BIDIRECTIONAL);
> + if (unlikely(dma_mapping_error(dev, addr))) {
> + percpu_stats->tx_dropped++;
> + return -ENOMEM;
> + }
> +
> + dpaa2_fd_set_addr(&fd, addr);
> + dpaa2_fd_set_offset(&fd, xdpf->data - buffer_start);
> + dpaa2_fd_set_len(&fd, xdpf->len);
> + dpaa2_fd_set_format(&fd, dpaa2_fd_single);
> + dpaa2_fd_set_ctrl(&fd, FD_CTRL_PTA);
> +
> + fq = &priv->fq[smp_processor_id()];
It is guaranteed that you have one FQ per CPU in the system?
> + for (i = 0; i < DPAA2_ETH_ENQUEUE_RETRIES; i++) {
> + err = priv->enqueue(priv, fq, &fd, 0);
> + if (err != -EBUSY)
> + break;
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
