Re: [PATCH v4 3/5] net: macb: fix macb_get/set_wol() when moving to phylink

From: Russell King - ARM Linux admin
Date: Wed May 13 2020 - 09:06:18 EST


On Wed, May 06, 2020 at 01:37:39PM +0200, nicolas.ferre@xxxxxxxxxxxxx wrote:
> From: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
>
> Keep previous function goals and integrate phylink actions to them.
>
> phylink_ethtool_get_wol() is not enough to figure out if Ethernet driver
> supports Wake-on-Lan.
> Initialization of "supported" and "wolopts" members is done in phylink
> function, no need to keep them in calling function.
>
> phylink_ethtool_set_wol() return value is not enough to determine
> if WoL is enabled for the calling Ethernet driver. Call it first
> but don't rely on its return value as most of simple PHY drivers
> don't implement a set_wol() function.
>
> Fixes: 7897b071ac3b ("net: macb: convert to phylink")
> Signed-off-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
> Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
> Cc: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
> Cc: Harini Katakam <harini.katakam@xxxxxxxxxx>
> Cc: Antoine Tenart <antoine.tenart@xxxxxxxxxxx>
> ---
> drivers/net/ethernet/cadence/macb_main.c | 18 ++++++++++--------
> 1 file changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index 53e81ab048ae..24c044dc7fa0 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -2817,21 +2817,23 @@ static void macb_get_wol(struct net_device *netdev, struct ethtool_wolinfo *wol)
> {
> struct macb *bp = netdev_priv(netdev);
>
> - wol->supported = 0;
> - wol->wolopts = 0;
> -
> - if (bp->wol & MACB_WOL_HAS_MAGIC_PACKET)
> + if (bp->wol & MACB_WOL_HAS_MAGIC_PACKET) {
> phylink_ethtool_get_wol(bp->phylink, wol);
> + wol->supported |= WAKE_MAGIC;
> +
> + if (bp->wol & MACB_WOL_ENABLED)
> + wol->wolopts |= WAKE_MAGIC;
> + }
> }
>
> static int macb_set_wol(struct net_device *netdev, struct ethtool_wolinfo *wol)
> {
> struct macb *bp = netdev_priv(netdev);
> - int ret;
>
> - ret = phylink_ethtool_set_wol(bp->phylink, wol);
> - if (!ret)
> - return 0;
> + /* Pass the order to phylink layer.
> + * Don't test return value as set_wol() is often not supported.
> + */
> + phylink_ethtool_set_wol(bp->phylink, wol);

If this returns an error, does that mean WOL works or does it not?

Note that if set_wol() is not supported, this will return -EOPNOTSUPP.
What about other errors?

If you want to just ignore the case where it's not supported, then
this looks like a sledge hammer to crack a nut.

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