From: Corentin Labbe <clabbe.montjoie@gmail.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: robh+dt@kernel.org, mark.rutland@arm.com,
maxime.ripard@free-electrons.com, wens@csie.org,
linux@armlinux.org.uk, catalin.marinas@arm.com,
will.deacon@arm.com, peppe.cavallaro@st.com,
alexandre.torgue@st.com, f.fainelli@gmail.com,
netdev@vger.kernel.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 10/10] net: stmmac: dwmac-sun8i: Handle integrated/external MDIOs
Date: Fri, 8 Sep 2017 16:28:25 +0200 [thread overview]
Message-ID: <20170908142825.GC3037@Red> (raw)
In-Reply-To: <20170908141736.GF25219@lunn.ch>
On Fri, Sep 08, 2017 at 04:17:36PM +0200, Andrew Lunn wrote:
> > > Do you know why the reset times out/fails?
> > >
> >
> > Because there are nothing connected to it.
>
> That should not be an issue. A read should just return 0xffff. And it
> should return 0xffff fast. The timing of the MDIO protocol is fixed. A
> read or a write takes a fixed number of cycles, independent of if
> there is a device there or not. The bus data line has a pullup, so if
> you try to access a missing device, you automatically read 0xffff.
>
Perhaps, but the reality is that with nothing connected to it, the reset of the MAC timeout.
Certainly, the MAC does not support finding no PHY.
So, to prevent an error message, and a "freeze" of the net process, the need_reset trick is necessary.
Regards
Corentin Labbe
next prev parent reply other threads:[~2017-09-08 14:28 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-08 7:11 [PATCH v5 00/10] net: stmmac: dwmac-sun8i: Handle integrated PHY Corentin Labbe
2017-09-08 7:11 ` [PATCH v5 01/10] arm64: dts: allwinner: Restore EMAC changes Corentin Labbe
2017-09-08 7:19 ` Maxime Ripard
[not found] ` <20170908071954.j2bhtw4wqa27fald-ZC1Zs529Oq4@public.gmane.org>
2017-09-08 7:36 ` Corentin Labbe
2017-09-08 7:39 ` Chen-Yu Tsai
[not found] ` <CAGb2v64K3XTLJwZwYmq3r64=3_bHHGTeGyC0gfoJfL5+Ty53ag-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-09-10 18:56 ` Corentin Labbe
2017-09-08 7:11 ` [PATCH v5 02/10] dt-bindings: net: Restore sun8i dwmac binding Corentin Labbe
2017-09-13 18:07 ` Rob Herring
2017-09-14 18:31 ` Corentin Labbe
2017-09-08 7:11 ` [PATCH v5 03/10] arm: dts: sunxi: Restore EMAC changes Corentin Labbe
[not found] ` <20170908071156.5115-1-clabbe.montjoie-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-09-08 7:11 ` [PATCH v5 04/10] net: stmmac: sun8i: Restore the compatibles Corentin Labbe
2017-09-08 7:11 ` [PATCH v5 05/10] dt-bindings: net: dwmac-sun8i: update documentation about integrated PHY Corentin Labbe
[not found] ` <20170908071156.5115-6-clabbe.montjoie-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-09-08 7:25 ` Maxime Ripard
[not found] ` <20170908072538.rqsp6dobwsqmzrsr-ZC1Zs529Oq4@public.gmane.org>
2017-09-08 7:43 ` Corentin Labbe
2017-09-13 18:20 ` Rob Herring
2017-09-14 18:53 ` Corentin Labbe
2017-09-14 19:19 ` Andrew Lunn
[not found] ` <20170914191949.GA3796-g2DYL2Zd6BY@public.gmane.org>
2017-09-19 5:31 ` Corentin Labbe
2017-09-20 2:49 ` Rob Herring
2017-09-20 18:23 ` Corentin Labbe
2017-09-08 7:11 ` [PATCH v5 06/10] ARM: dts: sunxi: h3/h5: represent the mdio switch used by sun8i-h3-emac Corentin Labbe
2017-09-08 7:11 ` [PATCH v5 07/10] arm64: dts: allwinner: add snps,dwmac-mdio compatible to emac/mdio Corentin Labbe
2017-09-08 7:11 ` [PATCH v5 08/10] net: stmmac: dwmac-sun8i: choose internal PHY via phy-is-integrated Corentin Labbe
2017-09-08 7:11 ` [PATCH v5 09/10] net: stmmac: snps,dwmac-mdio MDIOs are automatically registered Corentin Labbe
2017-09-08 7:11 ` [PATCH v5 10/10] net: stmmac: dwmac-sun8i: Handle integrated/external MDIOs Corentin Labbe
2017-09-08 13:05 ` Andrew Lunn
2017-09-08 13:26 ` Corentin Labbe
2017-09-08 14:00 ` Andrew Lunn
[not found] ` <20170908140020.GC25219-g2DYL2Zd6BY@public.gmane.org>
2017-09-08 14:08 ` Corentin Labbe
2017-09-08 14:17 ` Andrew Lunn
2017-09-08 14:28 ` Corentin Labbe [this message]
2017-09-11 16:11 ` Andrew Lunn
2017-09-11 19:08 ` Corentin Labbe
2017-09-11 20:19 ` Andrew Lunn
2017-09-12 7:54 ` Corentin Labbe
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