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

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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: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Vladimir Oltean 2023-04-18 14:14:51 +03:00 committed by Jakub Kicinski
parent 787e6144ae
commit 59be75db59
1 changed files with 7 additions and 4 deletions
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11
drivers/net/ethernet/freescale/enetc/enetc_ethtool.c
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@ -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))
val |= ENETC_MMCSR_ME;
/* 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);