[U-Boot] [PATCH 10/12][v3] driver/ldpaa_eth: Retry enqueue if portal was busy

[Joe Hershberger]

Hi Prabhakar,

On Sat, Jun 27, 2015 at 11:38 PM, Prabhakar Kushwaha
<prabhakar at freescale.com> wrote:
> Do not immediately return if the enqueue function returns -EBUSY; re-try
> mulitple times.
>
> if timeout occures, release the buffer.
>
> Signed-off-by: Prabhakar Kushwaha <prabhakar at freescale.com>
>
> driver/ldpaa_eth:Avoid infinite loop in QBMAN buf release
>
> Change infinite loop mechanism to timer based polling.
>
> ---
> Changes for v2: Sending as it is for patchset
> Changes for v3: Incorporated Joe Hershberger's comments
>     - Squash with "driver/ldpaa_eth:Avoid infinite loop in QBMAN buf release"
>     - use err instead of calling get_timer() again
>
>
>  drivers/net/ldpaa_eth/ldpaa_eth.c | 39 ++++++++++++++++++++++++++++++++++++---
>  1 file changed, 36 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ldpaa_eth/ldpaa_eth.c b/drivers/net/ldpaa_eth/ldpaa_eth.c
> index 5636511..275e316 100644
> --- a/drivers/net/ldpaa_eth/ldpaa_eth.c
> +++ b/drivers/net/ldpaa_eth/ldpaa_eth.c
> @@ -31,6 +31,8 @@ static void ldpaa_eth_rx(struct ldpaa_eth_priv *priv,
>         uint32_t fd_length;
>         struct ldpaa_fas *fas;
>         uint32_t status, err;
> +       u32 timeo = (CONFIG_SYS_HZ * 2) / 1000;
> +       u32 time_start;
>         struct qbman_release_desc releasedesc;
>         struct qbman_swp *swp = dflt_dpio->sw_portal;
>
> @@ -65,10 +67,15 @@ error:
>         flush_dcache_range(fd_addr, fd_addr + LDPAA_ETH_RX_BUFFER_SIZE);
>         qbman_release_desc_clear(&releasedesc);
>         qbman_release_desc_set_bpid(&releasedesc, dflt_dpbp->dpbp_attr.bpid);
> +       time_start = get_timer(0);
>         do {
>                 /* Release buffer into the QBMAN */
>                 err = qbman_swp_release(swp, &releasedesc, &fd_addr, 1);
> -       } while (err == -EBUSY);
> +       } while (get_timer(time_start) < timeo && err == -EBUSY);
> +
> +       if (err == -EBUSY)
> +               printf("Rx frame: QBMAN buffer release fails\n");
> +

I asked you to squash the "fix to ldpaa_eth_tx", not this
otherwise-unrelated change to ldpaa_eth_rx(). Please put this part
back in a separate patch.

>         return;
>  }
>
> @@ -221,8 +228,11 @@ static int ldpaa_eth_tx(struct eth_device *net_dev, void *buf, int len)
>         struct dpaa_fd fd;
>         u64 buffer_start;
>         int data_offset, err;
> +       u32 timeo = (CONFIG_SYS_HZ * 10) / 1000;
> +       u32 time_start;
>         struct qbman_swp *swp = dflt_dpio->sw_portal;
>         struct qbman_eq_desc ed;
> +       struct qbman_release_desc releasedesc;
>
>         /* Setup the FD fields */
>         memset(&fd, 0, sizeof(fd));
> @@ -258,9 +268,18 @@ static int ldpaa_eth_tx(struct eth_device *net_dev, void *buf, int len)
>         qbman_eq_desc_clear(&ed);
>         qbman_eq_desc_set_no_orp(&ed, 0);
>         qbman_eq_desc_set_qd(&ed, priv->tx_qdid, priv->tx_flow_id, 0);
> -       err = qbman_swp_enqueue(swp, &ed, (const struct qbman_fd *)(&fd));
> +
> +       time_start = get_timer(0);
> +
> +       while (get_timer(time_start) < timeo) {
> +               err = qbman_swp_enqueue(swp, &ed,
> +                               (const struct qbman_fd *)(&fd));
> +               if (err != -EBUSY)
> +                       break;
> +       }
> +
>         if (err < 0)
> -               printf("error enqueueing Tx frame\n");

You no longer have any place that you indicate this error to the
user... It seems you should have this either here or below in the
error: case.

> +               goto error;
>
>         mdelay(1);
>
> @@ -269,6 +288,20 @@ static int ldpaa_eth_tx(struct eth_device *net_dev, void *buf, int len)
>                 printf("error Tx Conf frame\n");
>
>         return err;
> +
> +error:
> +       qbman_release_desc_clear(&releasedesc);
> +       qbman_release_desc_set_bpid(&releasedesc, dflt_dpbp->dpbp_attr.bpid);
> +       time_start = get_timer(0);
> +       do {
> +               /* Release buffer into the QBMAN */
> +               err = qbman_swp_release(swp, &releasedesc, &buffer_start, 1);
> +       } while (get_timer(time_start) < timeo && err == -EBUSY);
> +
> +       if (err == -EBUSY)
> +               printf("TX data: QBMAN buffer release fails\n");
> +
> +       return err;
>  }
>
>  static int ldpaa_eth_open(struct eth_device *net_dev, bd_t *bd)
> --
> 1.9.1
>
>
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