Date:   Sat, 27 Jan 2018 12:26:55 +0530
From:   Harini Katakam <harinikatakamlinux@...il.com>
To:     Nicolas Ferre <nicolas.ferre@...el.com>,
        David Miller <davem@...emloft.net>,
        Harini Katakam <harinikatakamlinux@...il.com>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Harini Katakam <harinik@...inx.com>, michals@...inx.com,
        Harini Katakam <harini.katakam@...inx.com>,
        Michal Simek <michal.simek@...inx.com>
Subject: Re: [PATCH v3] net: macb: Handle HRESP error

Hi David,

On Sat, Jan 27, 2018 at 12:09 PM,  <harinikatakamlinux@...il.com> wrote:
> From: Harini Katakam <harini.katakam@...inx.com>
>
> Handle HRESP error by doing a SW reset of RX and TX and
> re-initializing the descriptors, RX and TX queue pointers.
>
> Signed-off-by: Harini Katakam <harinik@...inx.com>
> Signed-off-by: Michal Simek <michal.simek@...inx.com>
> ---
> v3 and v2 changes:
> Fixed patch formatting errors
> Rebased on latest net-next and reinitialized
> multiple rx queues in error handling.
>
>  drivers/net/ethernet/cadence/macb.h      |  3 ++
>  drivers/net/ethernet/cadence/macb_main.c | 59 +++++++++++++++++++++++++++++---
>  2 files changed, 58 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
> index c50c5ec..8665982 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -13,6 +13,7 @@
>  #include <linux/phy.h>
>  #include <linux/ptp_clock_kernel.h>
>  #include <linux/net_tstamp.h>
> +#include <linux/interrupt.h>
>
>  #if defined(CONFIG_ARCH_DMA_ADDR_T_64BIT) || defined(CONFIG_MACB_USE_HWSTAMP)
>  #define MACB_EXT_DESC
> @@ -1200,6 +1201,8 @@ struct macb {
>         struct ethtool_rx_fs_list rx_fs_list;
>         spinlock_t rx_fs_lock;
>         unsigned int max_tuples;
> +
> +       struct tasklet_struct   hresp_err_tasklet;
>  };
>
>  #ifdef CONFIG_MACB_USE_HWSTAMP
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index 234667e..e84afcf 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -1258,6 +1258,57 @@ static int macb_poll(struct napi_struct *napi, int budget)
>         return work_done;
>  }
>
> +static void macb_hresp_error_task(unsigned long data)
> +{
> +       struct macb *bp = (struct macb *)data;
> +       struct net_device *dev = bp->dev;
> +       struct macb_queue *queue = bp->queues;
> +       unsigned int q;
> +       u32 ctrl;
> +
> +       for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
> +               queue_writel(queue, IDR, MACB_RX_INT_FLAGS |
> +                                        MACB_TX_INT_FLAGS |
> +                                        MACB_BIT(HRESP));
> +       }
> +       ctrl = macb_readl(bp, NCR);
> +       ctrl &= ~(MACB_BIT(RE) | MACB_BIT(TE));
> +       macb_writel(bp, NCR, ctrl);
> +
> +       netif_tx_stop_all_queues(dev);
> +       netif_carrier_off(dev);
> +
> +       bp->macbgem_ops.mog_init_rings(bp);
> +
> +       /* Initialize TX and RX buffers */
> +       for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
> +               queue_writel(queue, RBQP, lower_32_bits(queue->rx_ring_dma));
> +#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> +               if (bp->hw_dma_cap & HW_DMA_CAP_64B)
> +                       queue_writel(queue, RBQPH,
> +                                    upper_32_bits(queue->rx_ring_dma));
> +#endif
> +               queue_writel(queue, TBQP, lower_32_bits(queue->tx_ring_dma));
> +#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> +               if (bp->hw_dma_cap & HW_DMA_CAP_64B)
> +                       queue_writel(queue, TBQPH,
> +                                    upper_32_bits(queue->tx_ring_dma));
> +#endif
> +
> +               /* Enable interrupts */
> +               queue_writel(queue, IER,
> +                            MACB_RX_INT_FLAGS |
> +                            MACB_TX_INT_FLAGS |
> +                            MACB_BIT(HRESP));
> +       }
> +
> +       ctrl |= MACB_BIT(RE) | MACB_BIT(TE);
> +       macb_writel(bp, NCR, ctrl);
> +
> +       netif_carrier_on(dev);
> +       netif_tx_start_all_queues(dev);
> +}
> +
>  static irqreturn_t macb_interrupt(int irq, void *dev_id)
>  {
>         struct macb_queue *queue = dev_id;
> @@ -1347,10 +1398,7 @@ static irqreturn_t macb_interrupt(int irq, void *dev_id)
>                 }
>
>                 if (status & MACB_BIT(HRESP)) {
> -                       /* TODO: Reset the hardware, and maybe move the
> -                        * netdev_err to a lower-priority context as well
> -                        * (work queue?)
> -                        */
> +                       tasklet_schedule(&bp->hresp_err_tasklet);
>                         netdev_err(dev, "DMA bus error: HRESP not OK\n");
>
>                         if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE)
> @@ -3937,6 +3985,9 @@ static int macb_probe(struct platform_device *pdev)
>                 goto err_out_unregister_mdio;
>         }
>
> +       tasklet_init(&bp->hresp_err_tasklet, macb_hresp_error_task,
> +                    (unsigned long)bp);
> +
>         phy_attached_info(phydev);
>
>         netdev_info(dev, "Cadence %s rev 0x%08x at 0x%08lx irq %d (%pM)\n",
> --
> 2.7.4
>

Apologies for the spam.
This is the v3. Please do let me know in case you still see any corruption.

Regards,
Harini

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