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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Sudheesh Mavila <sudheesh.mavila@amd.com>,
        Shyam Sundar S K <Shyam-sundar.S-k@amd.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 070/247] net: amd-xgbe: Reset link when the link never comes back
Date:   Mon,  1 Mar 2021 17:11:30 +0100
Message-Id: <20210301161035.112391119@linuxfoundation.org>
In-Reply-To: <20210301161031.684018251@linuxfoundation.org>
References: <20210301161031.684018251@linuxfoundation.org>
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From: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>

[ Upstream commit 84fe68eb67f9499309cffd97c1ba269de125ff14 ]

Normally, auto negotiation and reconnect should be automatically done by
the hardware. But there seems to be an issue where auto negotiation has
to be restarted manually. This happens because of link training and so
even though still connected to the partner the link never "comes back".
This needs an auto-negotiation restart.

Also, a change in xgbe-mdio is needed to get ethtool to recognize the
link down and get the link change message. This change is only
required in a backplane connection mode.

Fixes: abf0a1c2b26a ("amd-xgbe: Add support for SFP+ modules")
Co-developed-by: Sudheesh Mavila <sudheesh.mavila@amd.com>
Signed-off-by: Sudheesh Mavila <sudheesh.mavila@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/amd/xgbe/xgbe-mdio.c   | 2 +-
 drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c b/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c
index 4d5506d928973..156a0bc8ab01d 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-mdio.c
@@ -1345,7 +1345,7 @@ static void xgbe_phy_status(struct xgbe_prv_data *pdata)
 							     &an_restart);
 	if (an_restart) {
 		xgbe_phy_config_aneg(pdata);
-		return;
+		goto adjust_link;
 	}
 
 	if (pdata->phy.link) {
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
index 828d12bf523fe..1a617d6d2bf86 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c
@@ -2595,6 +2595,14 @@ static int xgbe_phy_link_status(struct xgbe_prv_data *pdata, int *an_restart)
 	if (reg & MDIO_STAT1_LSTATUS)
 		return 1;
 
+	if (pdata->phy.autoneg == AUTONEG_ENABLE &&
+	    phy_data->port_mode == XGBE_PORT_MODE_BACKPLANE) {
+		if (!test_bit(XGBE_LINK_INIT, &pdata->dev_state)) {
+			netif_carrier_off(pdata->netdev);
+			*an_restart = 1;
+		}
+	}
+
 	/* No link, attempt a receiver reset cycle */
 	if (phy_data->rrc_count++ > XGBE_RRC_FREQUENCY) {
 		phy_data->rrc_count = 0;
-- 
2.27.0