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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, Vladimir Oltean <vladimir.oltean@nxp.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 020/146] net: dsa: felix: re-enable TX flow control in ocelot_port_flush()
Date:   Mon, 21 Jun 2021 18:14:10 +0200
Message-Id: <20210621154911.958549234@linuxfoundation.org>
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From: Vladimir Oltean <vladimir.oltean@nxp.com>

[ Upstream commit 1650bdb1c516c248fb06f6d076559ff6437a5853 ]

Because flow control is set up statically in ocelot_init_port(), and not
in phylink_mac_link_up(), what happens is that after the blamed commit,
the flow control remains disabled after the port flushing procedure.

Fixes: eb4733d7cffc ("net: dsa: felix: implement port flushing on .phylink_mac_link_down")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/mscc/ocelot.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index aa400b925b08..5bfc7acfd13a 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -355,6 +355,7 @@ static u32 ocelot_read_eq_avail(struct ocelot *ocelot, int port)
 
 int ocelot_port_flush(struct ocelot *ocelot, int port)
 {
+	unsigned int pause_ena;
 	int err, val;
 
 	/* Disable dequeuing from the egress queues */
@@ -363,6 +364,7 @@ int ocelot_port_flush(struct ocelot *ocelot, int port)
 		       QSYS_PORT_MODE, port);
 
 	/* Disable flow control */
+	ocelot_fields_read(ocelot, port, SYS_PAUSE_CFG_PAUSE_ENA, &pause_ena);
 	ocelot_fields_write(ocelot, port, SYS_PAUSE_CFG_PAUSE_ENA, 0);
 
 	/* Disable priority flow control */
@@ -398,6 +400,9 @@ int ocelot_port_flush(struct ocelot *ocelot, int port)
 	/* Clear flushing again. */
 	ocelot_rmw_gix(ocelot, 0, REW_PORT_CFG_FLUSH_ENA, REW_PORT_CFG, port);
 
+	/* Re-enable flow control */
+	ocelot_fields_write(ocelot, port, SYS_PAUSE_CFG_PAUSE_ENA, pause_ena);
+
 	return err;
 }
 EXPORT_SYMBOL(ocelot_port_flush);
-- 
2.30.2