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From:   =?UTF-8?q?Michal=20Vok=C3=A1=C4=8D?= <michal.vokac@ysoft.com>
To:     Andrew Lunn <andrew@lunn.ch>,
        "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org
Cc:     Vivien Didelot <vivien.didelot@gmail.com>,
        linux-kernel@vger.kernel.org,
        Florian Fainelli <f.fainelli@gmail.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        =?UTF-8?q?Michal=20Vok=C3=A1=C4=8D?= <michal.vokac@ysoft.com>
Subject: [PATCH net] net: dsa: qca8k: Use up to 7 ports for all operations
Date:   Thu, 26 Sep 2019 10:59:17 +0200
Message-Id: <1569488357-31415-1-git-send-email-michal.vokac@ysoft.com>
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The QCA8K family supports up to 7 ports. So use the existing
QCA8K_NUM_PORTS define to allocate the switch structure and limit all
operations with the switch ports.

This was not an issue until commit 0394a63acfe2 ("net: dsa: enable and
disable all ports") disabled all unused ports. Since the unused ports 7-11
are outside of the correct register range on this switch some registers
were rewritten with invalid content.

Fixes: 6b93fb46480a ("net-next: dsa: add new driver for qca8xxx family")
Fixes: a0c02161ecfc ("net: dsa: variable number of ports")
Fixes: 0394a63acfe2 ("net: dsa: enable and disable all ports")
Signed-off-by: Michal Vokáč <michal.vokac@ysoft.com>
---
I am not sure which of the fixes tags should be used but this definetelly
fixes something..

IMHO the 0394a63acfe2 ("net: dsa: enable and disable all ports") did not
cause the issue but made it visible.

 drivers/net/dsa/qca8k.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index 16f15c93a102..bbeeb8618c80 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -705,7 +705,7 @@ qca8k_setup(struct dsa_switch *ds)
 		    BIT(0) << QCA8K_GLOBAL_FW_CTRL1_UC_DP_S);
 
 	/* Setup connection between CPU port & user ports */
-	for (i = 0; i < DSA_MAX_PORTS; i++) {
+	for (i = 0; i < QCA8K_NUM_PORTS; i++) {
 		/* CPU port gets connected to all user ports of the switch */
 		if (dsa_is_cpu_port(ds, i)) {
 			qca8k_rmw(priv, QCA8K_PORT_LOOKUP_CTRL(QCA8K_CPU_PORT),
@@ -1074,7 +1074,7 @@ qca8k_sw_probe(struct mdio_device *mdiodev)
 	if (id != QCA8K_ID_QCA8337)
 		return -ENODEV;
 
-	priv->ds = dsa_switch_alloc(&mdiodev->dev, DSA_MAX_PORTS);
+	priv->ds = dsa_switch_alloc(&mdiodev->dev, QCA8K_NUM_PORTS);
 	if (!priv->ds)
 		return -ENOMEM;
 
-- 
2.1.4