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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, Trevor Woerner <twoerner@gmail.com>,
        Vladimir Zapolskiy <vz@mleia.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.9 18/20] net: nxp: lpc_eth.c: avoid hang when bringing interface down
Date:   Mon,  1 Nov 2021 10:17:27 +0100
Message-Id: <20211101082447.960614660@linuxfoundation.org>
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From: Trevor Woerner <twoerner@gmail.com>

commit ace19b992436a257d9a793672e57abc28fe83e2e upstream.

A hard hang is observed whenever the ethernet interface is brought
down. If the PHY is stopped before the LPC core block is reset,
the SoC will hang. Comparing lpc_eth_close() and lpc_eth_open() I
re-arranged the ordering of the functions calls in lpc_eth_close() to
reset the hardware before stopping the PHY.
Fixes: b7370112f519 ("lpc32xx: Added ethernet driver")
Signed-off-by: Trevor Woerner <twoerner@gmail.com>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/nxp/lpc_eth.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/net/ethernet/nxp/lpc_eth.c
+++ b/drivers/net/ethernet/nxp/lpc_eth.c
@@ -1039,9 +1039,6 @@ static int lpc_eth_close(struct net_devi
 	napi_disable(&pldat->napi);
 	netif_stop_queue(ndev);
 
-	if (ndev->phydev)
-		phy_stop(ndev->phydev);
-
 	spin_lock_irqsave(&pldat->lock, flags);
 	__lpc_eth_reset(pldat);
 	netif_carrier_off(ndev);
@@ -1049,6 +1046,8 @@ static int lpc_eth_close(struct net_devi
 	writel(0, LPC_ENET_MAC2(pldat->net_base));
 	spin_unlock_irqrestore(&pldat->lock, flags);
 
+	if (ndev->phydev)
+		phy_stop(ndev->phydev);
 	clk_disable_unprepare(pldat->clk);
 
 	return 0;