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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,
        Codrin Ciubotariu <codrin.ciubotariu@microchip.com>,
        Andrew Lunn <andrew@lunn.ch>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 046/109] net: dsa: microchip: set the correct number of ports
Date:   Tue, 14 Jul 2020 20:43:49 +0200
Message-Id: <20200714184107.727844251@linuxfoundation.org>
In-Reply-To: <20200714184105.507384017@linuxfoundation.org>
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From: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>

[ 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@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/dsa/microchip/ksz8795.c | 3 +++
 drivers/net/dsa/microchip/ksz9477.c | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/drivers/net/dsa/microchip/ksz8795.c b/drivers/net/dsa/microchip/ksz8795.c
index 24a5e99f7fd5b..84c4319e3b31f 100644
--- a/drivers/net/dsa/microchip/ksz8795.c
+++ b/drivers/net/dsa/microchip/ksz8795.c
@@ -1267,6 +1267,9 @@ static int ksz8795_switch_init(struct ksz_device *dev)
 			return -ENOMEM;
 	}
 
+	/* set the real number of ports */
+	dev->ds->num_ports = dev->port_cnt;
+
 	return 0;
 }
 
diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index 50ffc63d62319..3afb596d8e43f 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -1587,6 +1587,9 @@ static int ksz9477_switch_init(struct ksz_device *dev)
 			return -ENOMEM;
 	}
 
+	/* set the real number of ports */
+	dev->ds->num_ports = dev->port_cnt;
+
 	return 0;
 }
 
-- 
2.25.1