[net] net: phylink: Fix flow control for fixed-link

In phylink_parse_fixedlink() the pl->link_config.advertising bits are AND
with pl->supported, pl->supported is zeroed and only the speed/duplex
modes and MII bits are set.
So pl->link_config.advertising always loses the flow control/pause bits.

By setting Pause and Asym_Pause bits in pl->supported, the flow control
work again when devicetree "pause" is set in fixes-link node and the MAC
advertise that is supports pause.

Results with this patch.

Legend:
- DT = 'Pause' is set in the fixed-link in devicetree.
- validate() = ‘Yes’ means phylink_set(mask, Pause) is set in the
  validate().
- flow = results reported my link is Up line.

+-----+------------+-------+
| DT  | validate() | flow  |
+-----+------------+-------+
| Yes | Yes        | rx/tx |
| No  | Yes        | off   |
| Yes | No         | off   |
+-----+------------+-------+

Fixes: 9525ae83959b ("phylink: add phylink infrastructure")
Signed-off-by: René van Dorst <opensource@vdorst.com>
---
 drivers/net/phy/phylink.c | 2 ++
 1 file changed, 2 insertions(+)

On Sat, Jul 27, 2019 at 11:40:11AM +0200, René van Dorst wrote:
> In phylink_parse_fixedlink() the pl->link_config.advertising bits are AND
> with pl->supported, pl->supported is zeroed and only the speed/duplex
> modes and MII bits are set.
> So pl->link_config.advertising always loses the flow control/pause bits.
> 
> By setting Pause and Asym_Pause bits in pl->supported, the flow control
> work again when devicetree "pause" is set in fixes-link node and the MAC
> advertise that is supports pause.
> 
> Results with this patch.
> 
> Legend:
> - DT = 'Pause' is set in the fixed-link in devicetree.
> - validate() = ‘Yes’ means phylink_set(mask, Pause) is set in the
>   validate().
> - flow = results reported my link is Up line.
> 
> +-----+------------+-------+
> | DT  | validate() | flow  |
> +-----+------------+-------+
> | Yes | Yes        | rx/tx |
> | No  | Yes        | off   |
> | Yes | No         | off   |
> +-----+------------+-------+
> 
> Fixes: 9525ae83959b ("phylink: add phylink infrastructure")
> Signed-off-by: René van Dorst <opensource@vdorst.com>

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>

Thanks.

> ---
>  drivers/net/phy/phylink.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
> index 5d0af041b8f9..a6aebaa14338 100644
> --- a/drivers/net/phy/phylink.c
> +++ b/drivers/net/phy/phylink.c
> @@ -216,6 +216,8 @@ static int phylink_parse_fixedlink(struct phylink *pl,
>  			       pl->supported, true);
>  	linkmode_zero(pl->supported);
>  	phylink_set(pl->supported, MII);
> +	phylink_set(pl->supported, Pause);
> +	phylink_set(pl->supported, Asym_Pause);
>  	if (s) {
>  		__set_bit(s->bit, pl->supported);
>  	} else {
> -- 
> 2.20.1
> 
>

From: René van Dorst <opensource@vdorst.com>
Date: Sat, 27 Jul 2019 11:40:11 +0200

> In phylink_parse_fixedlink() the pl->link_config.advertising bits are AND
> with pl->supported, pl->supported is zeroed and only the speed/duplex
> modes and MII bits are set.
> So pl->link_config.advertising always loses the flow control/pause bits.
> 
> By setting Pause and Asym_Pause bits in pl->supported, the flow control
> work again when devicetree "pause" is set in fixes-link node and the MAC
> advertise that is supports pause.
> 
> Results with this patch.
> 
> Legend:
> - DT = 'Pause' is set in the fixed-link in devicetree.
> - validate() = ‘Yes’ means phylink_set(mask, Pause) is set in the
>   validate().
> - flow = results reported my link is Up line.
> 
> +-----+------------+-------+
> | DT  | validate() | flow  |
> +-----+------------+-------+
> | Yes | Yes        | rx/tx |
> | No  | Yes        | off   |
> | Yes | No         | off   |
> +-----+------------+-------+
> 
> Fixes: 9525ae83959b ("phylink: add phylink infrastructure")
> Signed-off-by: René van Dorst <opensource@vdorst.com>

Applied and queued up for -stable, thanks.