Re: [PATCH net-next v7 2/3] net: phy: add support for clause 37 auto-negotiation

[Tao Ren <taoren@fb.com>]

On 8/11/19 4:40 PM, Tao Ren wrote:
> From: Heiner Kallweit <hkallweit1@gmail.com>
> 
> This patch adds support for clause 37 1000Base-X auto-negotiation.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> Signed-off-by: Tao Ren <taoren@fb.com>

A kind reminder: could someone help to review the patch when you have bandwidth?


Cheers,

Tao

> ---
>  Changes in v7:
>   - Update "if (AUTONEG_ENABLE != phydev->autoneg)" to
>     "if (phydev->autoneg != AUTONEG_ENABLE)" so checkpatch.pl is happy.
>  Changes in v6:
>   - add "Signed-off-by: Tao Ren <taoren@fb.com>"
>  Changes in v1-v5:
>   - nothing changed. It's given v5 just to align with the version of
>     patch series.
> 
>  drivers/net/phy/phy_device.c | 139 +++++++++++++++++++++++++++++++++++
>  include/linux/phy.h          |   5 ++
>  2 files changed, 144 insertions(+)
> 
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 252a712d1b2b..301a794b2963 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -1617,6 +1617,40 @@ static int genphy_config_advert(struct phy_device *phydev)
>  	return changed;
>  }
>  
> +/**
> + * genphy_c37_config_advert - sanitize and advertise auto-negotiation parameters
> + * @phydev: target phy_device struct
> + *
> + * Description: Writes MII_ADVERTISE with the appropriate values,
> + *   after sanitizing the values to make sure we only advertise
> + *   what is supported.  Returns < 0 on error, 0 if the PHY's advertisement
> + *   hasn't changed, and > 0 if it has changed. This function is intended
> + *   for Clause 37 1000Base-X mode.
> + */
> +static int genphy_c37_config_advert(struct phy_device *phydev)
> +{
> +	u16 adv = 0;
> +
> +	/* Only allow advertising what this PHY supports */
> +	linkmode_and(phydev->advertising, phydev->advertising,
> +		     phydev->supported);
> +
> +	if (linkmode_test_bit(ETHTOOL_LINK_MODE_1000baseX_Full_BIT,
> +			      phydev->advertising))
> +		adv |= ADVERTISE_1000XFULL;
> +	if (linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,
> +			      phydev->advertising))
> +		adv |= ADVERTISE_1000XPAUSE;
> +	if (linkmode_test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,
> +			      phydev->advertising))
> +		adv |= ADVERTISE_1000XPSE_ASYM;
> +
> +	return phy_modify_changed(phydev, MII_ADVERTISE,
> +				  ADVERTISE_1000XFULL | ADVERTISE_1000XPAUSE |
> +				  ADVERTISE_1000XHALF | ADVERTISE_1000XPSE_ASYM,
> +				  adv);
> +}
> +
>  /**
>   * genphy_config_eee_advert - disable unwanted eee mode advertisement
>   * @phydev: target phy_device struct
> @@ -1726,6 +1760,54 @@ int genphy_config_aneg(struct phy_device *phydev)
>  }
>  EXPORT_SYMBOL(genphy_config_aneg);
>  
> +/**
> + * genphy_c37_config_aneg - restart auto-negotiation or write BMCR
> + * @phydev: target phy_device struct
> + *
> + * Description: If auto-negotiation is enabled, we configure the
> + *   advertising, and then restart auto-negotiation.  If it is not
> + *   enabled, then we write the BMCR. This function is intended
> + *   for use with Clause 37 1000Base-X mode.
> + */
> +int genphy_c37_config_aneg(struct phy_device *phydev)
> +{
> +	int err, changed;
> +
> +	if (phydev->autoneg != AUTONEG_ENABLE)
> +		return genphy_setup_forced(phydev);
> +
> +	err = phy_modify(phydev, MII_BMCR, BMCR_SPEED1000 | BMCR_SPEED100,
> +			 BMCR_SPEED1000);
> +	if (err)
> +		return err;
> +
> +	changed = genphy_c37_config_advert(phydev);
> +	if (changed < 0) /* error */
> +		return changed;
> +
> +	if (!changed) {
> +		/* Advertisement hasn't changed, but maybe aneg was never on to
> +		 * begin with?  Or maybe phy was isolated?
> +		 */
> +		int ctl = phy_read(phydev, MII_BMCR);
> +
> +		if (ctl < 0)
> +			return ctl;
> +
> +		if (!(ctl & BMCR_ANENABLE) || (ctl & BMCR_ISOLATE))
> +			changed = 1; /* do restart aneg */
> +	}
> +
> +	/* Only restart aneg if we are advertising something different
> +	 * than we were before.
> +	 */
> +	if (changed > 0)
> +		return genphy_restart_aneg(phydev);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(genphy_c37_config_aneg);
> +
>  /**
>   * genphy_aneg_done - return auto-negotiation status
>   * @phydev: target phy_device struct
> @@ -1864,6 +1946,63 @@ int genphy_read_status(struct phy_device *phydev)
>  }
>  EXPORT_SYMBOL(genphy_read_status);
>  
> +/**
> + * genphy_c37_read_status - check the link status and update current link state
> + * @phydev: target phy_device struct
> + *
> + * Description: Check the link, then figure out the current state
> + *   by comparing what we advertise with what the link partner
> + *   advertises. This function is for Clause 37 1000Base-X mode.
> + */
> +int genphy_c37_read_status(struct phy_device *phydev)
> +{
> +	int lpa, err, old_link = phydev->link;
> +
> +	/* Update the link, but return if there was an error */
> +	err = genphy_update_link(phydev);
> +	if (err)
> +		return err;
> +
> +	/* why bother the PHY if nothing can have changed */
> +	if (phydev->autoneg == AUTONEG_ENABLE && old_link && phydev->link)
> +		return 0;
> +
> +	phydev->duplex = DUPLEX_UNKNOWN;
> +	phydev->pause = 0;
> +	phydev->asym_pause = 0;
> +
> +	if (phydev->autoneg == AUTONEG_ENABLE && phydev->autoneg_complete) {
> +		lpa = phy_read(phydev, MII_LPA);
> +		if (lpa < 0)
> +			return lpa;
> +
> +		linkmode_mod_bit(ETHTOOL_LINK_MODE_Autoneg_BIT,
> +				 phydev->lp_advertising, lpa & LPA_LPACK);
> +		linkmode_mod_bit(ETHTOOL_LINK_MODE_1000baseX_Full_BIT,
> +				 phydev->lp_advertising, lpa & LPA_1000XFULL);
> +		linkmode_mod_bit(ETHTOOL_LINK_MODE_Pause_BIT,
> +				 phydev->lp_advertising, lpa & LPA_1000XPAUSE);
> +		linkmode_mod_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,
> +				 phydev->lp_advertising,
> +				 lpa & LPA_1000XPAUSE_ASYM);
> +
> +		phy_resolve_aneg_linkmode(phydev);
> +	} else if (phydev->autoneg == AUTONEG_DISABLE) {
> +		int bmcr = phy_read(phydev, MII_BMCR);
> +
> +		if (bmcr < 0)
> +			return bmcr;
> +
> +		if (bmcr & BMCR_FULLDPLX)
> +			phydev->duplex = DUPLEX_FULL;
> +		else
> +			phydev->duplex = DUPLEX_HALF;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(genphy_c37_read_status);
> +
>  /**
>   * genphy_soft_reset - software reset the PHY via BMCR_RESET bit
>   * @phydev: target phy_device struct
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index 462b90b73f93..81a2921512ee 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -1077,6 +1077,11 @@ int genphy_suspend(struct phy_device *phydev);
>  int genphy_resume(struct phy_device *phydev);
>  int genphy_loopback(struct phy_device *phydev, bool enable);
>  int genphy_soft_reset(struct phy_device *phydev);
> +
> +/* Clause 37 */
> +int genphy_c37_config_aneg(struct phy_device *phydev);
> +int genphy_c37_read_status(struct phy_device *phydev);
> +
>  static inline int genphy_no_soft_reset(struct phy_device *phydev)
>  {
>  	return 0;
>