[PATCH] net: macb: dma_sync_* receive buffers

Sascha Hauer s.hauer at pengutronix.de
Mon Jun 3 23:49:18 PDT 2019


On Thu, May 30, 2019 at 02:28:15PM +0200, Ladislav Michl wrote:
> On Tue, Dec 04, 2018 at 08:58:01AM +0100, Sascha Hauer wrote:
> > Ladis,
> > 
> > On Fri, Nov 16, 2018 at 04:07:25PM +0100, Lucas Stach wrote:
> > > > @@ -237,12 +241,17 @@ static int macb_recv(struct eth_device *edev)
> > > > >  				taillen = length - headlen;
> > > > >  				memcpy((void *)NetRxPackets[0],
> > > > >  				       buffer, headlen);
> > > > > +				dma_sync_single_for_cpu((unsigned long)macb->rx_buffer,
> > > > > +							taillen, DMA_FROM_DEVICE);
> > > > >  				memcpy((void *)NetRxPackets[0] + headlen,
> > > >  				       macb->rx_buffer, taillen);
> > > 
> > > This is missing a dma_sync_single_for_device() here, matching the
> > > ...for_cpu added above. Otherwise patch looks good.
> > 
> > Any input to this one or an updated patch?
> 
> This must have slipped to the very bottom of my mailbox, sorry.
> 
> We should also not running sync outside buffer, if it is wrapped.
> Updated patch bellow.

Applied, thanks

Sascha

> 
> 	ladis
> 
> --- 8< ---
> 
> From: Ladislav Michl <ladis at linux-mips.org>
> Subject: [PATCH v2] net: macb: dma_sync_* receive buffers
> 
> Receive buffers are properly synchronized only if Cadence is
> GEM. Fix it for MACB as well.
> 
> Fixes: 86dc5259e25d (net: macb: no need for coherent memory for receive buffer)
> Signed-off-by: Ladislav Michl <ladis at linux-mips.org>
> ---
>  drivers/net/macb.c | 27 ++++++++++++++++++++-------
>  1 file changed, 20 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/macb.c b/drivers/net/macb.c
> index 0c0d17ee9..a0411d6e4 100644
> --- a/drivers/net/macb.c
> +++ b/drivers/net/macb.c
> @@ -209,9 +209,11 @@ static int macb_recv(struct eth_device *edev)
>  	dev_dbg(macb->dev, "%s\n", __func__);
>  
>  	for (;;) {
> +		barrier();
>  		if (!(macb->rx_ring[rx_tail].addr & MACB_BIT(RX_USED)))
>  			return -1;
>  
> +		barrier();
>  		status = macb->rx_ring[rx_tail].ctrl;
>  		if (status & MACB_BIT(RX_SOF)) {
>  			if (rx_tail != macb->rx_tail)
> @@ -228,14 +230,26 @@ static int macb_recv(struct eth_device *edev)
>  				headlen = macb->rx_buffer_size * (macb->rx_ring_size
>  						 - macb->rx_tail);
>  				taillen = length - headlen;
> -				memcpy((void *)NetRxPackets[0],
> -				       buffer, headlen);
> +				dma_sync_single_for_cpu((unsigned long)buffer,
> +							headlen, DMA_FROM_DEVICE);
> +				memcpy((void *)NetRxPackets[0], buffer, headlen);
> +				dma_sync_single_for_cpu((unsigned long)macb->rx_buffer,
> +							taillen, DMA_FROM_DEVICE);
>  				memcpy((void *)NetRxPackets[0] + headlen,
> -				       macb->rx_buffer, taillen);
> -				buffer = (void *)NetRxPackets[0];
> +					macb->rx_buffer, taillen);
> +				dma_sync_single_for_device((unsigned long)buffer,
> +							headlen, DMA_FROM_DEVICE);
> +				dma_sync_single_for_device((unsigned long)macb->rx_buffer,
> +							taillen, DMA_FROM_DEVICE);
> +				net_receive(edev, NetRxPackets[0], length);
> +			} else {
> +				dma_sync_single_for_cpu((unsigned long)buffer, length,
> +							DMA_FROM_DEVICE);
> +				net_receive(edev, buffer, length);
> +				dma_sync_single_for_device((unsigned long)buffer, length,
> +							DMA_FROM_DEVICE);
>  			}
> -
> -			net_receive(edev, buffer, length);
> +			barrier();
>  			if (++rx_tail >= macb->rx_ring_size)
>  				rx_tail = 0;
>  			reclaim_rx_buffers(macb, rx_tail);
> @@ -245,7 +259,6 @@ static int macb_recv(struct eth_device *edev)
>  				rx_tail = 0;
>  			}
>  		}
> -		barrier();
>  	}
>  
>  	return 0;
> -- 
> 2.20.1
> 
> 

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