Subject: Re: [PATCH net-next] [RFC] dpaa2-eth: Move DPAA2 Ethernet driver from staging to drivers/net

From: Andrew Lunn <[email-masked]>
Date: Fri, 3 Aug 2018 18:42:39 +0200

> +static int dpaa2_eth_probe(struct fsl_mc_device *dpni_dev)
> +{
> +	struct device *dev;
> +	struct net_device *net_dev = NULL;
> +	struct dpaa2_eth_priv *priv = NULL;
> +	int err = 0;
> +
> +	dev = &dpni_dev->dev;
> +
> +	/* Net device */
> +	net_dev = alloc_etherdev_mq(sizeof(*priv), DPAA2_ETH_MAX_TX_QUEUES);
> +	if (!net_dev) {
> +		dev_err(dev, "alloc_etherdev_mq() failed\n");
> +		return -ENOMEM;
> +	}
> +
> +	SET_NETDEV_DEV(net_dev, dev);
> +	dev_set_drvdata(dev, net_dev);
> +
> +	priv = netdev_priv(net_dev);
> +	priv->net_dev = net_dev;
> +
> +	priv->iommu_domain = iommu_get_domain_for_dev(dev);
> +
> +	/* Obtain a MC portal */
> +	err = fsl_mc_portal_allocate(dpni_dev, FSL_MC_IO_ATOMIC_CONTEXT_PORTAL,
> +				     &priv->mc_io);
> +	if (err) {
> +		if (err == -ENXIO)
> +			err = -EPROBE_DEFER;
> +		else
> +			dev_err(dev, "MC portal allocation failed\n");
> +		goto err_portal_alloc;
> +	}
> +
> +	/* MC objects initialization and configuration */
> +	err = setup_dpni(dpni_dev);
> +	if (err)
> +		goto err_dpni_setup;
> +
> +	err = setup_dpio(priv);
> +	if (err)
> +		goto err_dpio_setup;
> +
> +	setup_fqs(priv);
> +
> +	err = setup_dpbp(priv);
> +	if (err)
> +		goto err_dpbp_setup;
> +
> +	err = bind_dpni(priv);
> +	if (err)
> +		goto err_bind;
> +
> +	/* Add a NAPI context for each channel */
> +	add_ch_napi(priv);
> +
> +	/* Percpu statistics */
> +	priv->percpu_stats = alloc_percpu(*priv->percpu_stats);
> +	if (!priv->percpu_stats) {
> +		dev_err(dev, "alloc_percpu(percpu_stats) failed\n");
> +		err = -ENOMEM;
> +		goto err_alloc_percpu_stats;
> +	}
> +	priv->percpu_extras = alloc_percpu(*priv->percpu_extras);
> +	if (!priv->percpu_extras) {
> +		dev_err(dev, "alloc_percpu(percpu_extras) failed\n");
> +		err = -ENOMEM;
> +		goto err_alloc_percpu_extras;
> +	}
> +
> +	err = netdev_init(net_dev);
> +	if (err)
> +		goto err_netdev_init;

At the end of netdev_init() you call netdev_register(). From that
point on, you device is live. Its .ndo's can be called....

> +
> +	/* Configure checksum offload based on current interface flags */
> +	err = set_rx_csum(priv, !!(net_dev->features & NETIF_F_RXCSUM));
> +	if (err)
> +		goto err_csum;
> +
> +	err = set_tx_csum(priv, !!(net_dev->features &
> +				   (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM)));
> +	if (err)
> +		goto err_csum;
> +
> +	err = alloc_rings(priv);
> +	if (err)
> +		goto err_alloc_rings;

How well does the device work if it has not allocated the rings yet,
when it is asked to do something?

> +
> +	net_dev->ethtool_ops = &dpaa2_ethtool_ops;
> +
> +	err = setup_irqs(dpni_dev);

How well do it work without interrupts being set up?

> +	if (err) {
> +		netdev_warn(net_dev, "Failed to set link interrupt, fall back to polling\n");
> +		priv->poll_thread = kthread_run(poll_link_state, priv,
> +						"%s_poll_link", net_dev->name);
> +		if (IS_ERR(priv->poll_thread)) {
> +			netdev_err(net_dev, "Error starting polling thread\n");
> +			goto err_poll_thread;
> +		}
> +		priv->do_link_poll = true;
> +	}

Probably the correct place to register the netdev is here.

	 Andrew