[Linux-stm32] [PATCH 1/4] net: stmmac: update rx tail pointer register to fix rx dma hang issue.

[Jose Abreu]

From: Biao Huang <biao.huang at mediatek.com>
Date: Mon, Apr 29, 2019 at 07:15:53

> Currently we will not update the receive descriptor tail pointer in
> stmmac_rx_refill. Rx dma will think no available descriptors and stop
> once received packets exceed DMA_RX_SIZE, so that the rx only test will fail.
> 
> Update the receive tail pointer in stmmac_rx_refill to add more descriptors
> to the rx channel, so packets can be received continually
> 
> Signed-off-by: Biao Huang <biao.huang at mediatek.com>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 97c5e1a..818ad88 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -3336,6 +3336,9 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv, u32 queue)
>  		entry = STMMAC_GET_ENTRY(entry, DMA_RX_SIZE);
>  	}
>  	rx_q->dirty_rx = entry;
> +	stmmac_set_rx_tail_ptr(priv, priv->ioaddr,
> +			       rx_q->dma_rx_phy + (entry * sizeof(struct dma_desc)),

I think you can just use the "rx_q->rx_tail_addr" here. It'll always 
trigger a poll demand for the channel.

Thanks,
Jose Miguel Abreu