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Date: Thu, 21 Dec 2023 15:16:54 +0800
From: fuyao <fuyao@sjterm.com>
To: Jernej =?utf-8?Q?=C5=A0krabec?= <jernej.skrabec@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Jose Abreu <joabreu@synopsys.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Chen-Yu Tsai <wens@csie.org>, Samuel Holland <samuel@sholland.org>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>, netdev@vger.kernel.org,
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	linux-kernel@vger.kernel.org,
	=?utf-8?B?6bqm5YGl5bu6?= <maijianzhang@allwinnertech.com>
Subject: Re: [PATCH] gmac: sun8i: r40: add gmac tx_delay support
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	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
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	=?utf-8?B?6bqm5YGl5bu6?= <maijianzhang@allwinnertech.com>
References: <ZYKvCQBD-SY9uVLF@debian.cyg>
 <2370947.NG923GbCHz@jernej-laptop>
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Organization: work_work_work

On Wed, Dec 20, 2023 at 06:04:28PM +0100, Jernej Škrabec wrote:
> Dne sreda, 20. december 2023 ob 10:08:25 CET je fuyao napisal(a):
> > r40 can support tx_delay, so we add it.
> 
> I don't see how. User manual, 3.3.4.64. GMAC Clock Register talks only
> about RX delay.
> 

I don't see it in the user manual also.

it works fine in 100M, but it doesn't work good in 1G without tx_delay
in my board.

Read the sdk from allwinner I found in:

https://sourcegraph.com/github.com/tinalinux/linux-3.10/-/blob/arch/arm/boot/dts/sun8iw11p1.dtsi?L1826
https://sourcegraph.com/github.com/tinalinux/linux-3.10@r40-v1.y/-/blob/drivers/net/ethernet/allwinner/sunxi-gmac.c?L877

And I add it to my board, it works fine.

So, I think it may be exist register but not documented.

Best regards,
fuyao

> Best regards,
> Jernej
> 
> > 
> > Signed-off-by: fuyao <fuyao1697@cyg.com>
> > ---
> >  drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
> > index 137741b94122..fd07573afc9b 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
> > @@ -127,6 +127,7 @@ static const struct emac_variant emac_variant_r40 = {
> >  	.support_mii = true,
> >  	.support_rgmii = true,
> >  	.rx_delay_max = 7,
> > +	.tx_delay_max = 7,
> >  };
> >  
> >  static const struct emac_variant emac_variant_a64 = {
> > 
> 
> 
> 
>