net: dsa: felix: re-enable TX flow control in ocelot_port_flush()

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: eb4733d ("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>

Author: vladimiroltean

drivers/net/ethernet/mscc/ocelot.c

@@ -379,6 +379,7 @@ 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 */
@@ -387,6 +388,7 @@ 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 */
@@ -422,6 +424,9 @@ 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);