netdev - Re: [PATCH net-next v1 13/14] net: phy: nxp-c45-tja11xx: reset PCS if the link goes down

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Date: Fri, 16 Jun 2023 23:00:25 +0200
From: Andrew Lunn <andrew@...n.ch>
To: "Radu Pirea (NXP OSS)" <radu-nicolae.pirea@....nxp.com>
Cc: hkallweit1@...il.com, linux@...linux.org.uk, davem@...emloft.net,
	edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
	richardcochran@...il.com, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, sebastian.tobuschat@....com
Subject: Re: [PATCH net-next v1 13/14] net: phy: nxp-c45-tja11xx: reset PCS
 if the link goes down

On Fri, Jun 16, 2023 at 04:53:22PM +0300, Radu Pirea (NXP OSS) wrote:
> During PTP testing on early TJA1120 engineering samples I observed that
> if the link is lost and recovered, the tx timestamps will be randomly
> lost. To avoid this HW issue, the PCS should be reseted.
> 
> Resetting the PCS will break the link and we should reset the PCS on
> LINK UP -> LINK DOWN transition, otherwise we will trigger and infinite
> loop of LINK UP -> LINK DOWN events.

> +static int tja1120_read_status(struct phy_device *phydev)
> +{
> +	unsigned int link = phydev->link;
> +	int ret;

Maybe consider using link_change_notify:

        /**
         * @link_change_notify: Called to inform a PHY device driver
         * when the core is about to change the link state. This
         * callback is supposed to be used as fixup hook for drivers
         * that need to take action when the link state
         * changes. Drivers are by no means allowed to mess with the
         * PHY device structure in their implementations.
         */
        void (*link_change_notify)(struct phy_device *dev);

Seems like a fixup to me.

      Andrew