Commit 45c767fa authored by Russell King's avatar Russell King Committed by David S. Miller
Browse files

net: add linkmode helper for setting flow control advertisement 



Add a linkmode helper to set the flow control advertisement in an
ethtool linkmode mask according to the tx/rx capabilities. This
implementation is moved from phylib, and documented with an
analysis of its shortcomings.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a87ae8a9

drivers/net/phy/linkmode.c

+51 −0
Original line number Diff line number Diff line
@@ -42,3 +42,54 @@ void linkmode_resolve_pause(const unsigned long *local_adv, 
	}

}

EXPORT_SYMBOL_GPL(linkmode_resolve_pause);



/**

 * linkmode_set_pause - set the pause mode advertisement

 * @advertisement: advertisement in ethtool format

 * @tx: boolean from ethtool struct ethtool_pauseparam tx_pause member

 * @rx: boolean from ethtool struct ethtool_pauseparam rx_pause member

 *

 * Configure the advertised Pause and Asym_Pause bits according to the

 * capabilities of provided in @tx and @rx.

 *

 * We convert as follows:

 *  tx rx  Pause AsymDir

 *  0  0   0     0

 *  0  1   1     1

 *  1  0   0     1

 *  1  1   1     0

 *

 * Note: this translation from ethtool tx/rx notation to the advertisement

 * is actually very problematical. Here are some examples:

 *

 * For tx=0 rx=1, meaning transmit is unsupported, receive is supported:

 *

 *  Local device  Link partner

 *  Pause AsymDir Pause AsymDir Result

 *    1     1       1     0     TX + RX - but we have no TX support.

 *    1     1       0     1	Only this gives RX only

 *

 * For tx=1 rx=1, meaning we have the capability to transmit and receive

 * pause frames:

 *

 *  Local device  Link partner

 *  Pause AsymDir Pause AsymDir Result

 *    1     0       0     1     Disabled - but since we do support tx and rx,

 *				this should resolve to RX only.

 *

 * Hence, asking for:

 *  rx=1 tx=0 gives Pause+AsymDir advertisement, but we may end up

 *            resolving to tx+rx pause or only rx pause depending on

 *            the partners advertisement.

 *  rx=0 tx=1 gives AsymDir only, which will only give tx pause if

 *            the partners advertisement allows it.

 *  rx=1 tx=1 gives Pause only, which will only allow tx+rx pause

 *            if the other end also advertises Pause.

 */

void linkmode_set_pause(unsigned long *advertisement, bool tx, bool rx)

{

	linkmode_mod_bit(ETHTOOL_LINK_MODE_Pause_BIT, advertisement, rx);

	linkmode_mod_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, advertisement,

			 rx ^ tx);

}

EXPORT_SYMBOL_GPL(linkmode_set_pause);

drivers/net/phy/phy_device.c

+1 −16
Original line number Diff line number Diff line
@@ -2361,22 +2361,7 @@ void phy_set_asym_pause(struct phy_device *phydev, bool rx, bool tx) 
	__ETHTOOL_DECLARE_LINK_MODE_MASK(oldadv);



	linkmode_copy(oldadv, phydev->advertising);



	linkmode_clear_bit(ETHTOOL_LINK_MODE_Pause_BIT,

			   phydev->advertising);

	linkmode_clear_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,

			   phydev->advertising);



	if (rx) {

		linkmode_set_bit(ETHTOOL_LINK_MODE_Pause_BIT,

				 phydev->advertising);

		linkmode_set_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,

				 phydev->advertising);

	}



	if (tx)

		linkmode_change_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,

				    phydev->advertising);

	linkmode_set_pause(phydev->advertising, tx, rx);



	if (!linkmode_equal(oldadv, phydev->advertising) &&

	    phydev->autoneg)

include/linux/linkmode.h

+2 −0
Original line number Diff line number Diff line
@@ -92,4 +92,6 @@ void linkmode_resolve_pause(const unsigned long *local_adv, 
			    const unsigned long *partner_adv,

			    bool *tx_pause, bool *rx_pause);



void linkmode_set_pause(unsigned long *advertisement, bool tx, bool rx);



#endif /* __LINKMODE_H */

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