linux-kernel - Re: [PATCH net] net: macb: fix for fixed-link mode

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Message-ID: <91a5684d-9170-fdf6-3cd1-ae0636f3727b@microchip.com>
Date:   Fri, 10 Jan 2020 11:53:24 +0000
From:   <Claudiu.Beznea@...rochip.com>
To:     <mparab@...ence.com>, <Nicolas.Ferre@...rochip.com>,
        <jakub.kicinski@...ronome.com>, <andrew@...n.ch>,
        <antoine.tenart@...tlin.com>, <rmk+kernel@...linux.org.uk>
CC:     <f.fainelli@...il.com>, <davem@...emloft.net>,
        <netdev@...r.kernel.org>, <hkallweit1@...il.com>,
        <linux-kernel@...r.kernel.org>, <dkangude@...ence.com>,
        <a.fatoum@...gutronix.de>, <brad.mouring@...com>,
        <pthombar@...ence.com>
Subject: Re: [PATCH net] net: macb: fix for fixed-link mode



On 10.01.2020 07:46, Milind Parab wrote:
> This patch fix the issue with fixed link. With fixed-link
> device opening fails due to macb_phylink_connect not
> handling fixed-link mode, in which case no MAC-PHY connection
> is needed and phylink_connect return success (0), however
> in current driver attempt is made to search and connect to
> PHY even for fixed-link.
> 
> Fixes: 7897b071ac3b ("net: macb: convert to phylink")
> Signed-off-by: Milind Parab <mparab@...ence.com>
> ---
>  drivers/net/ethernet/cadence/macb_main.c | 24 +++++++++++++++---------
>  1 file changed, 15 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index c5ee363ca5dc..41c485485619 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -611,21 +611,24 @@ static const struct phylink_mac_ops macb_phylink_ops = {
>         .mac_link_up = macb_mac_link_up,
>  };
> 
> +static bool macb_phy_handle_exists(struct device_node *dn)
> +{
> +       dn = of_parse_phandle(dn, "phy-handle", 0);
> +       of_node_put(dn);
> +       return dn != NULL;
> +}
> +
>  static int macb_phylink_connect(struct macb *bp)
>  {
>         struct net_device *dev = bp->dev;
>         struct phy_device *phydev;
> +       struct device_node *dn = bp->pdev->dev.of_node;
>         int ret;
> 
> -       if (bp->pdev->dev.of_node &&
> -           of_parse_phandle(bp->pdev->dev.of_node, "phy-handle", 0)) {
> -               ret = phylink_of_phy_connect(bp->phylink, bp->pdev->dev.of_node,
> -                                            0);
> -               if (ret) {
> -                       netdev_err(dev, "Could not attach PHY (%d)\n", ret);
> -                       return ret;
> -               }
> -       } else {
> +       if (dn)
> +               ret = phylink_of_phy_connect(bp->phylink, dn, 0);
> +
> +       if (!dn || (ret && !macb_phy_handle_exists(dn))) {
>                 phydev = phy_find_first(bp->mii_bus);
>                 if (!phydev) {
>                         netdev_err(dev, "no PHY found\n");
> @@ -638,6 +641,9 @@ static int macb_phylink_connect(struct macb *bp)
>                         netdev_err(dev, "Could not attach to PHY (%d)\n", ret);
>                         return ret;
>                 }
> +       } else if (ret) {
> +               netdev_err(dev, "Could not attach PHY (%d)\n", ret);
> +               return ret;
>         }

You can remove this "else if (ret)" branch and also:
	if (ret) {
               netdev_err(dev, "Could not attach PHY (%d)\n", ret);
               return ret;
	}

under "if (!dn || (ret && !macb_phy_handle_exists(dn)))" and have something
like:

static int macb_phylink_connect(struct macb *bp)
{
	struct net_device *dev = bp->dev;
	struct phy_device *phydev;
	struct device_node *dn = bp->pdev->dev.of_node;
	int ret;

	if (dn)
		ret = phylink_of_phy_connect(bp->phylink, dn, 0);

	if (!dn || (ret && !macb_phy_handle_exists(dn))) {
		phydev = phy_find_first(bp->mii_bus);
		if (!phydev) {
			netdev_err(dev, "no PHY found\n");
			return -ENXIO;
		}

		/* attach the mac to the phy */
		ret = phylink_connect_phy(bp->phylink, phydev);
	}

	if (ret) {
		netdev_err(dev, "Could not attach PHY (%d)\n", ret);
		return ret;
	}

	phylink_start(bp->phylink);

	return 0;
}

> 
>         phylink_start(bp->phylink);
> --
> 2.17.1
> 
>