Re: [PATCH v8 2/2] net: Add mhi-net driver

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Wed, Oct 28, 2020 at 05:34:58PM +0100, Loic Poulain wrote:
> This patch adds a new network driver implementing MHI transport for
> network packets. Packets can be in any format, though QMAP (rmnet)
> is the usual protocol (flow control + PDN mux).
> 
> It support two MHI devices, IP_HW0 which is, the path to the IPA
> (IP accelerator) on qcom modem, And IP_SW0 which is the software
> driven IP path (to modem CPU).
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> ---
>   v2: - rebase on net-next
>       - remove useless skb_linearize
>       - check error type on mhi_queue return
>       - rate limited errors
>       - Schedule RX refill only on 'low' buf level
>       - SET_NETDEV_DEV in probe
>       - reorder device remove sequence
>   v3: - Stop channels on net_register error
>       - Remove useles parentheses
>       - Add driver .owner
>   v4: - prevent potential cpu hog in rx-refill loop
>       - Access mtu via READ_ONCE
>   v5: - Fix access to u64 stats
>   v6: - Stop TX queue earlier if queue is full
>       - Preventing 'abnormal' NETDEV_TX_BUSY path
>   v7: - Stop dl/ul cb operations on channel resetting
>   v8: - remove premature comment about TX threading gain
>       - check rx_queued to determine queuing limits
>       - fix probe error path (unified goto usage)
> 
>  drivers/net/Kconfig   |   7 ++
>  drivers/net/Makefile  |   1 +
>  drivers/net/mhi_net.c | 313 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 321 insertions(+)
>  create mode 100644 drivers/net/mhi_net.c
> 

[...]

> +static int mhi_net_probe(struct mhi_device *mhi_dev,
> +			 const struct mhi_device_id *id)
> +{
> +	const char *netname = (char *)id->driver_data;
> +	struct mhi_net_dev *mhi_netdev;
> +	struct net_device *ndev;
> +	struct device *dev = &mhi_dev->dev;
> +	int err;
> +
> +	ndev = alloc_netdev(sizeof(*mhi_netdev), netname, NET_NAME_PREDICTABLE,
> +			    mhi_net_setup);
> +	if (!ndev)
> +		return -ENOMEM;
> +
> +	mhi_netdev = netdev_priv(ndev);
> +	dev_set_drvdata(dev, mhi_netdev);
> +	mhi_netdev->ndev = ndev;
> +	mhi_netdev->mdev = mhi_dev;
> +	SET_NETDEV_DEV(ndev, &mhi_dev->dev);
> +
> +	/* All MHI net channels have 128 ring elements (at least for now) */
> +	mhi_netdev->rx_queue_sz = 128;
> +
> +	INIT_DELAYED_WORK(&mhi_netdev->rx_refill, mhi_net_rx_refill_work);
> +	u64_stats_init(&mhi_netdev->stats.rx_syncp);
> +	u64_stats_init(&mhi_netdev->stats.tx_syncp);
> +
> +	/* Start MHI channels */
> +	err = mhi_prepare_for_transfer(mhi_dev);
> +	if (err)
> +		goto out_prep_err;
> +
> +	err = register_netdev(ndev);
> +	if (err)
> +		goto out_register_err;
> +
> +	return 0;
> +
> +out_register_err:
> +	mhi_unprepare_from_transfer(mhi_dev);

Missed this one. MHI stack will do this for you incase of failure.

Thanks,
Mani