[xdp-hints] Re: [PATCH net-next v4 2/3] net: stmmac: add Rx HWTS metadata to XDP receive pkt

[Stanislav Fomichev <sdf@google.com>]

On Wed, Apr 12, 2023 at 8:26 PM Song Yoong Siang
<yoong.siang.song@intel.com> wrote:
>
> Add receive hardware timestamp metadata support via kfunc to XDP receive
> packets.
>
> Suggested-by: Stanislav Fomichev <sdf@google.com>
> Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>

Conceptually looks good, thanks!
Acked-by: Stanislav Fomichev <sdf@google.com>


> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac.h  |  3 ++
>  .../net/ethernet/stmicro/stmmac/stmmac_main.c | 40 ++++++++++++++++++-
>  2 files changed, 42 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
> index ac8ccf851708..826ac0ec88c6 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
> @@ -94,6 +94,9 @@ struct stmmac_rx_buffer {
>
>  struct stmmac_xdp_buff {
>         struct xdp_buff xdp;
> +       struct stmmac_priv *priv;
> +       struct dma_desc *p;
> +       struct dma_desc *np;
>  };
>
>  struct stmmac_rx_queue {
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 6ffce52ca837..831a3e22e0d8 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -5313,10 +5313,15 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
>
>                         xdp_init_buff(&ctx.xdp, buf_sz, &rx_q->xdp_rxq);
>                         xdp_prepare_buff(&ctx.xdp, page_address(buf->page),
> -                                        buf->page_offset, buf1_len, false);
> +                                        buf->page_offset, buf1_len, true);
>
>                         pre_len = ctx.xdp.data_end - ctx.xdp.data_hard_start -
>                                   buf->page_offset;
> +
> +                       ctx.priv = priv;
> +                       ctx.p = p;
> +                       ctx.np = np;
> +
>                         skb = stmmac_xdp_run_prog(priv, &ctx.xdp);
>                         /* Due xdp_adjust_tail: DMA sync for_device
>                          * cover max len CPU touch
> @@ -7060,6 +7065,37 @@ void stmmac_fpe_handshake(struct stmmac_priv *priv, bool enable)
>         }
>  }
>
> +static int stmmac_xdp_rx_timestamp(const struct xdp_md *_ctx, u64 *timestamp)
> +{
> +       const struct stmmac_xdp_buff *ctx = (void *)_ctx;
> +       struct stmmac_priv *priv = ctx->priv;
> +       struct dma_desc *desc = ctx->p;
> +       struct dma_desc *np = ctx->np;
> +       struct dma_desc *p = ctx->p;
> +       u64 ns = 0;
> +
> +       if (!priv->hwts_rx_en)
> +               return -ENODATA;
> +
> +       /* For GMAC4, the valid timestamp is from CTX next desc. */
> +       if (priv->plat->has_gmac4 || priv->plat->has_xgmac)
> +               desc = np;
> +
> +       /* Check if timestamp is available */
> +       if (stmmac_get_rx_timestamp_status(priv, p, np, priv->adv_ts)) {
> +               stmmac_get_timestamp(priv, desc, priv->adv_ts, &ns);
> +               ns -= priv->plat->cdc_error_adj;
> +               *timestamp = ns_to_ktime(ns);
> +               return 0;
> +       }
> +
> +       return -ENODATA;
> +}
> +
> +static const struct xdp_metadata_ops stmmac_xdp_metadata_ops = {
> +       .xmo_rx_timestamp               = stmmac_xdp_rx_timestamp,
> +};
> +
>  /**
>   * stmmac_dvr_probe
>   * @device: device pointer
> @@ -7167,6 +7203,8 @@ int stmmac_dvr_probe(struct device *device,
>
>         ndev->netdev_ops = &stmmac_netdev_ops;
>
> +       ndev->xdp_metadata_ops = &stmmac_xdp_metadata_ops;
> +
>         ndev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
>                             NETIF_F_RXCSUM;
>         ndev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
> --
> 2.34.1
>