[PATCH 6/6] net: sun8i-emac: v3s: fix soft reset timeout

[Andre Przywara]

On Thu, 20 May 2021 00:10:47 +0200
Andreas Rehn <rehn.andreas86 at gmail.com> wrote:

> hey,
> 
> sure. I give it a try tomorrow.
> with 250 ms, for example, I ran into timeouts after the first tftp download.
> after a manual retry, it works fine but retry is not a valid production
> behavior.

Just read the arch timer after the SOFT_RST write and after the first
read of 0 again, and I got 17-18 ticks on my OrangePi Zero (H2+). So at
24MHz this is less than a *micro*second for the MAC to reset. So the 10
ms are already plenty.
Are you sure that it's this timeout value that is improving things for
you?

Cheers,
Andre

> greetings
> Andreas
> 
> Am Mi., 19. Mai 2021 um 23:45 Uhr schrieb Andre Przywara <
> andre.przywara at arm.com>:  
> 
> > On Wed, 19 May 2021 21:42:08 +0200
> > Andreas Rehn <rehn.andreas86 at gmail.com> wrote:
> >
> > Hi,
> >  
> > > v3s emac soft reset tooks quit longer if autonegation is active
> > > on 100 Mbit full duplex pairs what can result in
> > > `sun8i_emac_eth_start: Timeout` error  
> >
> > Mmmh, why the 500ms? Can you figure out how long it typically
> > takes for you? By open-coding wait_for_bit_le32() and printing the time
> > it took to flip the bit back?
> >
> > Happy to change this then when we have some data.
> >
> > Cheers,
> > Andre
> >  
> > > wait_for_bit_le32 polls register value each ms.
> > > Increasing the timeout for setup do not effect current behavior
> > > but reduces unexpected behaviors (e.g. timeouts on tftp download).
> > >
> > > Signed-off-by: Andreas Rehn <rehn.andreas86 at gmail.com>
> > > ---
> > >  drivers/net/sun8i_emac.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/net/sun8i_emac.c b/drivers/net/sun8i_emac.c
> > > index 0e7ad3b0d4..23fd35f9e1 100644
> > > --- a/drivers/net/sun8i_emac.c
> > > +++ b/drivers/net/sun8i_emac.c
> > > @@ -475,7 +475,7 @@ static int sun8i_emac_eth_start(struct udevice *dev)
> > >       /* Soft reset MAC */
> > >       writel(EMAC_CTL1_SOFT_RST, priv->mac_reg + EMAC_CTL1);
> > >       ret = wait_for_bit_le32(priv->mac_reg + EMAC_CTL1,
> > > -                             EMAC_CTL1_SOFT_RST, false, 10, true);
> > > +                             EMAC_CTL1_SOFT_RST, false, 500, true);
> > >       if (ret) {
> > >               printf("%s: Timeout\n", __func__);
> > >               return ret;  
> >
> >  
>