Re: [PATCH net-next v3 1/1] net: phy: marvell: avoid bringing down fibre link when autoneg is bypassed

[Mateusz Polchlopek <mateusz.polchlopek@intel.com>]

On 10/3/2024 9:10 AM, Qingtao Cao wrote:
> On 88E151x the SGMII autoneg bypass mode defaults to be enabled. When it is
> activated, the device assumes a link-up status with existing configuration
> in BMCR, avoid bringing down the fibre link in this case
> 
> Test case:
> 1. Two 88E151x connected with SFP, both enable autoneg, link is up with
>     speed 1000M
> 2. Disable autoneg on one device and explicitly set its speed to 1000M
> 3. The fibre link can still up with this change, otherwise not.
> 
> Signed-off-by: Qingtao Cao <qingtao.cao@digi.com>
> ---
>   drivers/net/phy/marvell.c | 14 ++++++++++++++
>   1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
> index 9964bf3dea2f..efc4b2317466 100644
> --- a/drivers/net/phy/marvell.c
> +++ b/drivers/net/phy/marvell.c
> @@ -195,6 +195,10 @@
>   
>   #define MII_88E1510_MSCR_2		0x15
>   
> +#define MII_88E1510_FSCR2		0x1a
> +#define MII_88E1510_FSCR2_BYPASS_ENABLE	BIT(6)
> +#define MII_88E1510_FSCR2_BYPASS_STATUS	BIT(5)
> +
>   #define MII_VCT5_TX_RX_MDI0_COUPLING	0x10
>   #define MII_VCT5_TX_RX_MDI1_COUPLING	0x11
>   #define MII_VCT5_TX_RX_MDI2_COUPLING	0x12
> @@ -1623,11 +1627,21 @@ static void fiber_lpa_mod_linkmode_lpa_t(unsigned long *advertising, u32 lpa)
>   static int marvell_read_status_page_an(struct phy_device *phydev,
>   				       int fiber, int status)
>   {
> +	int fscr2;
>   	int lpa;
>   	int err;
>   
>   	if (!(status & MII_M1011_PHY_STATUS_RESOLVED)) {
>   		phydev->link = 0;
> +		if (fiber) {
> +			fscr2 = phy_read(phydev, MII_88E1510_FSCR2);
> +			if (fscr2 < 0)
> +				return fscr2;
> +			if ((fscr2 & MII_88E1510_FSCR2_BYPASS_ENABLE) &&
> +			    (fscr2 & MII_88E1510_FSCR2_BYPASS_STATUS) &&
> +			    (genphy_read_status_fixed(phydev) == 0))
> +				phydev->link = 1;
> +		}
>   		return 0;
>   	}
>   

LGTM.

Reviewed-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>