linux-kernel - Re: [PATCH net-next 0/4] net: phy: mscc-miim: reduce waiting time between MDIO transactions

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Message-ID: <159056285904.265465.1821646548974311512@kwain>
Date:   Wed, 27 May 2020 09:00:59 +0200
From:   Antoine Tenart <antoine.tenart@...tlin.com>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     davem@...emloft.net, f.fainelli@...il.com, hkallweit1@...il.com,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        alexandre.belloni@...tlin.com, thomas.petazzoni@...tlin.com,
        allan.nielsen@...rochip.com
Subject: Re: [PATCH net-next 0/4] net: phy: mscc-miim: reduce waiting time between MDIO transactions

Hi Andrew,

Quoting Andrew Lunn (2020-05-26 19:01:00)
> On Tue, May 26, 2020 at 06:22:52PM +0200, Antoine Tenart wrote:
> > 
> > This series aims at reducing the waiting time between MDIO transactions
> > when using the MSCC MIIM MDIO controller.
> 
> There are a couple of other things you can look at:
> 
> Can you disable the pre-amble on the MDIO transaction. It requires
> that both the bus master and all devices on the bus support it, but
> when it is usable, you half the number of bits sent over the wire.
> 
> Can you control the frequency of MDC? 802.3 says 2.5MHz, but many
> devices support higher speeds. Again, you need all devices on the bus
> to support the speed.
> 
> When accessing raw TDR data for cable tests i also have a lot of PHY
> accesses. I implemented both of these for the FEC MDIO bus, and made
> it a lot faster.

Thanks for the tips!

Antoine

-- 
Antoine Ténart, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com