diff mbox series

[net,1/2] net: dsa: b53: Fix calculating number of switch ports

Message ID 20210901092141.6451-1-zajec5@gmail.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [net,1/2] net: dsa: b53: Fix calculating number of switch ports | expand

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Commit Message

Rafał Miłecki Sept. 1, 2021, 9:21 a.m. UTC 
From: Rafał Miłecki <rafal@milecki.pl>

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: 967dd82ffc52 ("net: dsa: b53: Add support for Broadcom RoboSwitch")
Cc: stable@vger.kernel.org
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
 drivers/net/dsa/b53/b53_common.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Comments

Florian Fainelli Sept. 1, 2021, 5:16 p.m. UTC | #1 
On 9/1/2021 2:21 AM, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal@milecki.pl>
> 
> 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: 967dd82ffc52 ("net: dsa: b53: Add support for Broadcom RoboSwitch")
> Cc: stable@vger.kernel.org
> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

For a bug fix, this looks appropriate to me, and for net-next, we need 
to remove the dev->num_ports and b53_for_each_port() entirely as there 
is no need to duplicate what DSA already maintains for us. Thanks!

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
diff mbox series

Patch

diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index bd1417a66cbf..dcf9d7e5ae14 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -2612,9 +2612,8 @@  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);
 
 	/* Include non standard CPU port built-in PHYs to be probed */
 	if (is539x(dev) || is531x5(dev)) {