Re: [PATCH v4 for-next] RDMA/core: Get IB width and speed from netdev

[Leon Romanovsky <leon@kernel.org>]

On Fri, Jul 21, 2023 at 05:20:52PM +0800, Junxian Huang wrote:
> From: Haoyue Xu <xuhaoyue1@hisilicon.com>
> 
> Previously, there was no way to query the number of lanes for a network
> card, so the same netdev_speed would result in a fixed pair of width and
> speed. As network card specifications become more diverse, such fixed
> mode is no longer suitable, so a method is needed to obtain the correct
> width and speed based on the number of lanes.
> 
> This patch retrieves netdev lanes and speed from net_device and
> translates them to IB width and speed.
> 
> Signed-off-by: Haoyue Xu <xuhaoyue1@hisilicon.com>
> Signed-off-by: Luoyouming <luoyouming@huawei.com>
> Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
> ---
>  drivers/infiniband/core/verbs.c | 100 +++++++++++++++++++++++++-------
>  1 file changed, 79 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
> index b99b3cc283b6..25367bd6dd97 100644
> --- a/drivers/infiniband/core/verbs.c
> +++ b/drivers/infiniband/core/verbs.c
> @@ -1880,6 +1880,80 @@ int ib_modify_qp_with_udata(struct ib_qp *ib_qp, struct ib_qp_attr *attr,
>  }
>  EXPORT_SYMBOL(ib_modify_qp_with_udata);
>  
> +static void ib_get_width_and_speed(u32 netdev_speed, u32 lanes,
> +				   u16 *speed, u8 *width)

<...>

> +	switch (netdev_speed / lanes) {
> +	case SPEED_2500:
> +		*speed = IB_SPEED_SDR;
> +		break;
> +	case SPEED_5000:
> +		*speed = IB_SPEED_DDR;
> +		break;
> +	case SPEED_10000:
> +		*speed = IB_SPEED_FDR10;
> +		break;
> +	case SPEED_14000:
> +		*speed = IB_SPEED_FDR;
> +		break;
> +	case SPEED_25000:
> +		*speed = IB_SPEED_EDR;
> +		break;
> +	case SPEED_50000:
> +		*speed = IB_SPEED_HDR;
> +		break;
> +	case SPEED_100000:
> +		*speed = IB_SPEED_NDR;
> +		break;
> +	default:
> +		*speed = IB_SPEED_SDR;
> +	}

How did you come to these translation values?

Thanks