netdev - Re: [net-next, PATCH 1/2] net: netsec: initialize tx ring on ndo

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Message-ID: <CAKv+Gu9tdWM=ECwB0HaPuc=dCvPS0=3jtye8gctW9SoVi0b18Q@mail.gmail.com>
Date:   Wed, 19 Jun 2019 11:40:40 +0200
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Ilias Apalodimas <ilias.apalodimas@...aro.org>
Cc:     Jaswinder Singh <jaswinder.singh@...aro.org>,
        "<netdev@...r.kernel.org>" <netdev@...r.kernel.org>,
        Masahisa Kojima <masahisa.kojima@...aro.org>,
        "David S. Miller" <davem@...emloft.net>
Subject: Re: [net-next, PATCH 1/2] net: netsec: initialize tx ring on ndo_open

On Wed, 19 Jun 2019 at 09:57, Ilias Apalodimas
<ilias.apalodimas@...aro.org> wrote:
>
> Since we changed the Tx ring handling and now depend not bit31 to figure

s/not/on/

> out the owner of the descriptor, we should initialize this every time
> the device goes down-up instead of doing it once on driver init. If the
> value is not correctly initialized the device won't have any available
> descriptors
>
> Fixes: 35e07d23473972b8876f98bcfc631ebcf779e870 ("net: socionext: remove mmio reads on Tx")
>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@...aro.org>

Acked-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>

> ---
>  drivers/net/ethernet/socionext/netsec.c | 32 ++++++++++++++-----------
>  1 file changed, 18 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
> index cba5881b2746..a10ef700f16d 100644
> --- a/drivers/net/ethernet/socionext/netsec.c
> +++ b/drivers/net/ethernet/socionext/netsec.c
> @@ -1029,7 +1029,6 @@ static void netsec_free_dring(struct netsec_priv *priv, int id)
>  static int netsec_alloc_dring(struct netsec_priv *priv, enum ring_id id)
>  {
>         struct netsec_desc_ring *dring = &priv->desc_ring[id];
> -       int i;
>
>         dring->vaddr = dma_alloc_coherent(priv->dev, DESC_SZ * DESC_NUM,
>                                           &dring->desc_dma, GFP_KERNEL);
> @@ -1040,19 +1039,6 @@ static int netsec_alloc_dring(struct netsec_priv *priv, enum ring_id id)
>         if (!dring->desc)
>                 goto err;
>
> -       if (id == NETSEC_RING_TX) {
> -               for (i = 0; i < DESC_NUM; i++) {
> -                       struct netsec_de *de;
> -
> -                       de = dring->vaddr + (DESC_SZ * i);
> -                       /* de->attr is not going to be accessed by the NIC
> -                        * until netsec_set_tx_de() is called.
> -                        * No need for a dma_wmb() here
> -                        */
> -                       de->attr = 1U << NETSEC_TX_SHIFT_OWN_FIELD;
> -               }
> -       }
> -
>         return 0;
>  err:
>         netsec_free_dring(priv, id);
> @@ -1060,6 +1046,23 @@ static int netsec_alloc_dring(struct netsec_priv *priv, enum ring_id id)
>         return -ENOMEM;
>  }
>
> +static void netsec_setup_tx_dring(struct netsec_priv *priv)
> +{
> +       struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_TX];
> +       int i;
> +
> +       for (i = 0; i < DESC_NUM; i++) {
> +               struct netsec_de *de;
> +
> +               de = dring->vaddr + (DESC_SZ * i);
> +               /* de->attr is not going to be accessed by the NIC
> +                * until netsec_set_tx_de() is called.
> +                * No need for a dma_wmb() here
> +                */
> +               de->attr = 1U << NETSEC_TX_SHIFT_OWN_FIELD;
> +       }
> +}
> +
>  static int netsec_setup_rx_dring(struct netsec_priv *priv)
>  {
>         struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_RX];
> @@ -1361,6 +1364,7 @@ static int netsec_netdev_open(struct net_device *ndev)
>
>         pm_runtime_get_sync(priv->dev);
>
> +       netsec_setup_tx_dring(priv);
>         ret = netsec_setup_rx_dring(priv);
>         if (ret) {
>                 netif_err(priv, probe, priv->ndev,
> --
> 2.20.1
>