On Thu, 13 Jan 2022, Ricardo Martinez wrote:
> From: Haijun Liu <haijun.liu@xxxxxxxxxxxx>
>
> Creates the Cross Core Modem Network Interface (CCMNI) which implements
> the wwan_ops for registration with the WWAN framework, CCMNI also
> implements the net_device_ops functions used by the network device.
> Network device operations include open, close, start transmission, TX
> timeout, change MTU, and select queue.
>
> Signed-off-by: Haijun Liu <haijun.liu@xxxxxxxxxxxx>
> Co-developed-by: Chandrashekar Devegowda <chandrashekar.devegowda@xxxxxxxxx>
> Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@xxxxxxxxx>
> Co-developed-by: Ricardo Martinez <ricardo.martinez@xxxxxxxxxxxxxxx>
> Signed-off-by: Ricardo Martinez <ricardo.martinez@xxxxxxxxxxxxxxx>
> ---
> +static int t7xx_ccmni_open(struct net_device *dev)
> +{
> + struct t7xx_ccmni *ccmni = wwan_netdev_drvpriv(dev);
> +
> + netif_carrier_on(dev);
> + netif_tx_start_all_queues(dev);
> + atomic_inc(&ccmni->usage);
> + return 0;
> +}
> +
> +static int t7xx_ccmni_close(struct net_device *dev)
> +{
> + struct t7xx_ccmni *ccmni = wwan_netdev_drvpriv(dev);
> +
> + if (atomic_dec_return(&ccmni->usage) < 0)
> + return -EINVAL;
I'm certainly way out of my expertize here in knowing how/when these open
and close can be called. That kept in mind, I wonder if there's need to do
rollback for the atomic dec.
> +static void t7xx_ccmni_wwan_setup(struct net_device *dev)
> +{
> + dev->header_ops = NULL;
> + dev->hard_header_len += sizeof(struct ccci_header);
> +
> + dev->mtu = ETH_DATA_LEN;
> + dev->max_mtu = CCMNI_MTU_MAX;
> + dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
> + dev->watchdog_timeo = CCMNI_NETDEV_WDT_TO;
> + /* CCMNI is a pure IP device */
> + dev->flags = IFF_POINTOPOINT | IFF_NOARP;
> +
> + /* Not supporting VLAN */
> + dev->features = NETIF_F_VLAN_CHALLENGED;
> +
> + dev->features |= NETIF_F_SG;
> + dev->hw_features |= NETIF_F_SG;
> +
> + /* Uplink checksum offload */
> + dev->features |= NETIF_F_HW_CSUM;
> + dev->hw_features |= NETIF_F_HW_CSUM;
> +
> + /* Downlink checksum offload */
> + dev->features |= NETIF_F_RXCSUM;
> + dev->hw_features |= NETIF_F_RXCSUM;
> +
> + /* Use kernel default free_netdev() function */
> + dev->needs_free_netdev = true;
> +
> + /* No need to free again because of free_netdev() */
> + dev->priv_destructor = NULL;
Isn't the struct zeroed for you?
Maybe some of those comments are not that useful?
> + ctlb->capability = NIC_CAP_TXBUSY_STOP | NIC_CAP_SGIO |
> + NIC_CAP_DATA_ACK_DVD | NIC_CAP_CCMNI_MQ;
Is capability going to remain constant? And some of these are
not used at all.
Related to this, e.g., the NETIF_F_SG setting above doesn't seem to care
about what is in capability (assuming SGIO means what I think it does),
should it?
> + /* WWAN core will create a netdev for the default IP MUX channel */
> + ret = wwan_register_ops(dev, &ccmni_wwan_ops, ctlb, IP_MUX_SESSION_DEFAULT);
> + if (ret)
> + goto err_unregister_ops;
> +
> + init_md_status_notifier(t7xx_dev);
> +
> + return 0;
> +
> +err_unregister_ops:
> + wwan_unregister_ops(dev);
If wwan_register_ops fails, why is wwan_unregister_ops needed?
> +/* Must be less than DPMAIF_HW_MTU_SIZE (3*1024 + 8) */
This could be enforced with BUILD_BUG_ON if you want.
--
i.
