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From: Lucas Stach <l.stach@pengutronix.de>
To: Ladislav Michl <ladis@linux-mips.org>, barebox@lists.infradead.org
Subject: Re: [PATCH] net: macb: dma_sync_* receive buffers
Date: Fri, 16 Nov 2018 16:07:25 +0100	[thread overview]
Message-ID: <1542380845.23489.24.camel@pengutronix.de> (raw)
In-Reply-To: <20181115003637.GA16443@lenoch>

Am Donnerstag, den 15.11.2018, 01:36 +0100 schrieb Ladislav Michl:
> 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@linux-mips.org>
> ---
>  Hi Sascha,
> 
>  I'm unsure this is proper fix, but works for me (as well as
>  reverting 86dc5259e25d)
> 
>  drivers/net/macb.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/macb.c b/drivers/net/macb.c
> index 1c5752d10..2bd5b62a4 100644
> --- a/drivers/net/macb.c
> +++ b/drivers/net/macb.c
> @@ -216,9 +216,11 @@ 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)
> @@ -229,6 +231,8 @@ static int macb_recv(struct eth_device *edev)
> >  		if (status & MACB_BIT(RX_EOF)) {
> >  			buffer = macb->rx_buffer + macb->rx_buffer_size * macb->rx_tail;
> >  			length = MACB_BFEXT(RX_FRMLEN, status);
> > +			dma_sync_single_for_cpu((unsigned long)buffer, length,
> > +						DMA_FROM_DEVICE);
> >  			if (wrapped) {
> >  				unsigned int headlen, taillen;
>  
> @@ -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.

Regards,
Lucas

>  				buffer = (void *)NetRxPackets[0];
> >  			}
>  
> >  			net_receive(edev, buffer, length);
> > +			dma_sync_single_for_device((unsigned long)buffer, length,
> > +						   DMA_FROM_DEVICE);
> > +			barrier();
> >  			if (++rx_tail >= macb->rx_ring_size)
> >  				rx_tail = 0;
> >  			reclaim_rx_buffers(macb, rx_tail);
> @@ -252,7 +261,6 @@ static int macb_recv(struct eth_device *edev)
> >  				rx_tail = 0;
> >  			}
> >  		}
> > -		barrier();
> >  	}
>  
> >  	return 0;

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  reply	other threads:[~2018-11-16 15:07 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-15  0:36 Ladislav Michl
2018-11-16 15:07 ` Lucas Stach [this message]
2018-12-04  7:58   ` Sascha Hauer
2019-05-30 12:28     ` Ladislav Michl
2019-06-04  6:49       ` Sascha Hauer

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