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From:   gregkh@linuxfoundation.org
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Vladimir Oltean <vladimir.oltean@nxp.com>,
        Andrew Lunn <andrew@lunn.ch>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.10 050/290] net: dsa: sja1105: fix SGMII PCS being forced to SPEED_UNKNOWN instead of SPEED_10
Date:   Mon, 15 Mar 2021 14:52:23 +0100
Message-Id: <20210315135543.615398964@linuxfoundation.org>
In-Reply-To: <20210315135541.921894249@linuxfoundation.org>
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Vladimir Oltean <vladimir.oltean@nxp.com>

commit 053d8ad10d585adf9891fcd049637536e2fe9ea7 upstream.

When using MLO_AN_PHY or MLO_AN_FIXED, the MII_BMCR of the SGMII PCS is
read before resetting the switch so it can be reprogrammed afterwards.
This works for the speeds of 1Gbps and 100Mbps, but not for 10Mbps,
because SPEED_10 is actually 0, so AND-ing anything with 0 is false,
therefore that last branch is dead code.

Do what others do (genphy_read_status_fixed, phy_mii_ioctl) and just
remove the check for SPEED_10, let it fall into the default case.

Fixes: ffe10e679cec ("net: dsa: sja1105: Add support for the SGMII port")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/dsa/sja1105/sja1105_main.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -1834,7 +1834,7 @@ out_unlock_ptp:
 				speed = SPEED_1000;
 			else if (bmcr & BMCR_SPEED100)
 				speed = SPEED_100;
-			else if (bmcr & BMCR_SPEED10)
+			else
 				speed = SPEED_10;
 
 			sja1105_sgmii_pcs_force_speed(priv, speed);