Commit 59be75db authored by Vladimir Oltean's avatar Vladimir Oltean Committed by Jakub Kicinski
Browse files

net: enetc: fix MAC Merge layer remaining enabled until a link down event 



Current enetc_set_mm() is designed to set the priv->active_offloads bit
ENETC_F_QBU for enetc_mm_link_state_update() to act on, but if the link
is already up, it modifies the ENETC_MMCSR_ME ("Merge Enable") bit
directly.

The problem is that it only *sets* ENETC_MMCSR_ME if the link is up, it
doesn't *clear* it if needed. So subsequent enetc_get_mm() calls still
see tx-enabled as true, up until a link down event, which is when
enetc_mm_link_state_update() will get called.

This is not a functional issue as far as I can assess. It has only come
up because I'd like to uphold a simple API rule in core ethtool code:
the pMAC cannot be disabled if TX is going to be enabled. Currently,
the fact that TX remains enabled for longer than expected (after the
enetc_set_mm() call that disables it) is going to violate that rule,
which is how it was caught.

Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: default avatarSimon Horman <simon.horman@corigine.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 787e6144

drivers/net/ethernet/freescale/enetc/enetc_ethtool.c

+7 −4
Original line number Diff line number Diff line
@@ -1041,10 +1041,13 @@ static int enetc_set_mm(struct net_device *ndev, struct ethtool_mm_cfg *cfg, 
	else

		priv->active_offloads &= ~ENETC_F_QBU;



	/* If link is up, enable MAC Merge right away */

	if (!!(priv->active_offloads & ENETC_F_QBU) &&

	    !(val & ENETC_MMCSR_LINK_FAIL))

	/* If link is up, enable/disable MAC Merge right away */

	if (!(val & ENETC_MMCSR_LINK_FAIL)) {

		if (!!(priv->active_offloads & ENETC_F_QBU))

			val |= ENETC_MMCSR_ME;

		else

			val &= ~ENETC_MMCSR_ME;

	}



	val &= ~ENETC_MMCSR_VT_MASK;

	val |= ENETC_MMCSR_VT(cfg->verify_time);