[PATCH net-next v3 4/5] ionic: report the operational FEC mode from ethtool --show-fec

[Eric Joyner <eric.joyner@amd.com>]

From: "Nikhil P. Rao" <nikhil.rao@amd.com>

ionic_get_fecparam() fills fec->active_fec from config.fec_type, the mode
the host requested, which on an autoneg link is whatever was last
programmed while the link negotiates something else.  Read it from
status.fec_type, where firmware reports the operational mode.

status.fec_type was carved out of the reserved area by commit
c4e7a75a096c ("ionic: updates to ionic FW api description"), and
firmware older than that leaves the byte reserved, where zero reads as
IONIC_PORT_FEC_TYPE_NONE, so --show-fec reports FEC off on a link that
may be running it.

Poisoning the byte before PORT_INIT, the way the driver marks unwritten
extra_stats counters with IONIC_STAT_INVALID, does not work here:
firmware builds the whole port status block and writes it over the DMA
region, so the marker is gone whether or not that firmware knows the
field.  Accept the wrong answer on firmware that old.

Signed-off-by: Nikhil P. Rao <nikhil.rao@amd.com>
Signed-off-by: Eric Joyner <eric.joyner@amd.com>
---
 drivers/net/ethernet/pensando/ionic/ionic_ethtool.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_ethtool.c b/drivers/net/ethernet/pensando/ionic/ionic_ethtool.c
index bf7c70438a8c..2e067481bb15 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_ethtool.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_ethtool.c
@@ -442,8 +442,10 @@ static int ionic_get_fecparam(struct net_device *netdev,
 	lif = netdev_priv(netdev);
 	port_info = lif->ionic->idev.port_info;
 
-	fec->active_fec = ionic_fec_type_to_ethtool(port_info->config.fec_type);
-	fec->fec = ionic_fec_type_to_ethtool(port_info->config.fec_type);
+	fec->active_fec =
+		ionic_fec_type_to_ethtool(READ_ONCE(port_info->status.fec_type));
+	fec->fec =
+		ionic_fec_type_to_ethtool(READ_ONCE(port_info->config.fec_type));
 
 	return 0;
 }

-- 
2.53.0