[U-Boot] [Drivers PATCH 14/19] net/macb: workaround for transmission hang issue

[Albert ARIBAUD]

On Sun, 3 Feb 2013 12:19:26 +0100, Albert ARIBAUD
<albert.u.boot at aribaud.net> wrote:

> Hi Vipin,
> 
> On Fri, 2 Nov 2012 23:09:59 +0530, Vipin Kumar <vipin.kumar at st.com>
> wrote:
> 
> > From: Shiraz Hashim <shiraz.hashim at st.com>
> > 
> > It is observed on SPEAr320S RMII#1 interface that on transmitting
> > packets the MAC dma hangs randomly and constantly showing busy tx-go
> > state.
> > 
> > It comes out if this situation only when Transmission is disabled and
> > enabled again.
> > 
> > Since it happens randomly and u-boot doesn't require high performance we
> > disable TE and re-enable it on each transmission. We also change number
> > of transmit descriptor to 1 as we would not require more than it, further
> > it would not alter GMAC notion of transmit descriptor start queue as it
> > always point to same descriptor.
> > 
> > Signed-off-by: Shiraz Hashim <shiraz.hashim at st.com>
> > ---
> >  drivers/net/macb.c | 38 ++++++++++++++++++++++++++++++++++----
> >  1 file changed, 34 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/net/macb.c b/drivers/net/macb.c
> > index ac25b52..17bad33 100644
> > --- a/drivers/net/macb.c
> > +++ b/drivers/net/macb.c
> > @@ -55,7 +55,7 @@
> >  
> >  #define CONFIG_SYS_MACB_RX_BUFFER_SIZE		4096
> >  #define CONFIG_SYS_MACB_RX_RING_SIZE		(CONFIG_SYS_MACB_RX_BUFFER_SIZE / 128)
> > -#define CONFIG_SYS_MACB_TX_RING_SIZE		16
> > +#define CONFIG_SYS_MACB_TX_RING_SIZE		1
> >  #define CONFIG_SYS_MACB_TX_TIMEOUT		1000
> >  #define CONFIG_SYS_MACB_AUTONEG_TIMEOUT	5000000
> >  
> > @@ -226,7 +226,13 @@ static int macb_send(struct eth_device *netdev, void *packet, int length)
> >  	macb->tx_ring[tx_head].ctrl = ctrl;
> >  	macb->tx_ring[tx_head].addr = paddr;
> >  	barrier();
> > -	macb_writel(macb, NCR, MACB_BIT(TE) | MACB_BIT(RE) | MACB_BIT(TSTART));
> > +	/*
> > +	 * Due to issues on SPEAr320 RMII, disable TE first so that
> > +	 * controller can come out if it is hanged during transmission
> > +	 */
> > +	macb_writel(macb, NCR, macb_readl(macb, NCR) & ~MACB_BIT(TE));
> > +	macb_writel(macb, NCR, macb_readl(macb, NCR) |
> > +			MACB_BIT(TE) | MACB_BIT(TSTART));
> >  
> >  	/*
> >  	 * I guess this is necessary because the networking core may
> > @@ -444,6 +450,31 @@ static int macb_phy_init(struct macb_device *macb)
> >  	}
> >  }
> >  
> > +static void macb_reset_hw(struct macb_device *bp)
> > +{
> > +	/* Make sure we have the write buffer for ourselves */
> > +	barrier();
> > +	/*
> > +	 * Disable RX and TX (XXX: Should we halt the transmission
> > +	 * more gracefully?) and we should not close the mdio port
> > +	 */
> > +	macb_writel(bp, NCR, 0);
> > +
> > +	/* Clear the stats registers (XXX: Update stats first?) */
> > +	macb_writel(bp, NCR, MACB_BIT(CLRSTAT));
> > +
> > +	/* keep the mdio port , otherwise other eth will not work */
> > +	macb_writel(bp, NCR, MACB_BIT(MPE));
> > +
> > +	/* Clear all status flags */
> > +	macb_writel(bp, TSR, ~0UL);
> > +	macb_writel(bp, RSR, ~0UL);
> > +
> > +	/* Disable all interrupts */
> > +	macb_writel(bp, IDR, ~0UL);
> > +	macb_readl(bp, ISR);
> > +}
> > +
> >  static int macb_init(struct eth_device *netdev, bd_t *bd)
> >  {
> >  	struct macb_device *macb = to_macb(netdev);
> > @@ -520,8 +551,7 @@ static void macb_halt(struct eth_device *netdev)
> >  		tsr = macb_readl(macb, TSR);
> >  	} while (tsr & MACB_BIT(TGO));
> >  
> > -	/* Disable TX and RX, and clear statistics */
> > -	macb_writel(macb, NCR, MACB_BIT(CLRSTAT));
> > +	macb_reset_hw(macb);
> >  }
> >  
> >  static int macb_write_hwaddr(struct eth_device *dev)
> 
> This patch did not reappear in later versions of the series, and no
> other standalone patch seems to match it. Was it dropped?

Ping?

Amicalement,
-- 
Albert.