[PATCH 5.7 009/244] net: dsa: microchip: set the correct number of ports

[Greg Kroah-Hartman]

From: Codrin Ciubotariu <codrin.ciubotariu@xxxxxxxxxxxxx>

[ Upstream commit af199a1a9cb02ec0194804bd46c174b6db262075 ]

The number of ports is incorrectly set to the maximum available for a DSA
switch. Even if the extra ports are not used, this causes some functions
to be called later, like port_disable() and port_stp_state_set(). If the
driver doesn't check the port index, it will end up modifying unknown
registers.

Fixes: b987e98e50ab ("dsa: add DSA switch driver for Microchip KSZ9477")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@xxxxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/dsa/microchip/ksz8795.c |    3 +++
 drivers/net/dsa/microchip/ksz9477.c |    3 +++
 2 files changed, 6 insertions(+)

--- a/drivers/net/dsa/microchip/ksz8795.c
+++ b/drivers/net/dsa/microchip/ksz8795.c
@@ -1271,6 +1271,9 @@ static int ksz8795_switch_init(struct ks
 	/* set the real number of ports */
 	dev->ds->num_ports = dev->port_cnt;
 
+	/* set the real number of ports */
+	dev->ds->num_ports = dev->port_cnt;
+
 	return 0;
 }
 
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -516,6 +516,9 @@ static int ksz9477_port_vlan_filtering(s
 			     PORT_VLAN_LOOKUP_VID_0, false);
 	}
 
+	/* set the real number of ports */
+	dev->ds->num_ports = dev->port_cnt;
+
 	return 0;
 }