net: dsa: b53: Fix calculating number of switch ports

Rafał Miłecki · gregkh · commit 5d0be300bd08 · 2021-09-22T11:43:10.000+02:00
[ Upstream commit cdb067d31c0fe4cce98b9d15f1f2ef525acaa094 ] It isn't true that CPU port is always the last one. Switches BCM5301x have 9 ports (port 6 being inactive) and they use port 5 as CPU by default (depending on design some other may be CPU ports too). A more reliable way of determining number of ports is to check for the last set bit in the "enabled_ports" bitfield. This fixes b53 internal state, it will allow providing accurate info to the DSA and is required to fix BCM5301x support. Fixes: 967dd82 ("net: dsa: b53: Add support for Broadcom RoboSwitch") Signed-off-by: Rafał Miłecki <rafal@milecki.pl> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
@@ -1798,9 +1798,8 @@ static int b53_switch_init(struct b53_device *dev)
 			dev->cpu_port = 5;
 	}
 
-	/* cpu port is always last */
-	dev->num_ports = dev->cpu_port + 1;
 	dev->enabled_ports |= BIT(dev->cpu_port);
+	dev->num_ports = fls(dev->enabled_ports);
 
 	dev->ports = devm_kzalloc(dev->dev,
 				  sizeof(struct b53_port) * dev->num_ports,

Original file line number	Diff line number	Diff line change
`@@ -1798,9 +1798,8 @@ static int b53_switch_init(struct b53_device *dev)`
`1798`	`1798`	`dev->cpu_port = 5;`
`1799`	`1799`	`}`
`1800`	`1800`
`1801`		`- /* cpu port is always last */`
`1802`		`- dev->num_ports = dev->cpu_port + 1;`
`1803`	`1801`	`dev->enabled_ports \|= BIT(dev->cpu_port);`
	`1802`	`+ dev->num_ports = fls(dev->enabled_ports);`
`1804`	`1803`
`1805`	`1804`	`dev->ports = devm_kzalloc(dev->dev,`
`1806`	`1805`	`sizeof(struct b53_port) * dev->num_ports,`