[PATCH net] net: dsa: mv88e6xxx: Enable IGMP snooping on user ports only

[PATCH net] net: dsa: mv88e6xxx: Enable IGMP snooping on user ports only

[Fabio Estevam]

From: Steffen Bätz <steffen@innosonix.de>

Do not set the MV88E6XXX_PORT_CTL0_IGMP_MLD_SNOOP bit on CPU or DSA ports.

This allows the host CPU port to be a regular IGMP listener by sending out
IGMP Membership Reports, which would otherwise not be forwarded by the
mv88exxx chip, but directly looped back to the CPU port itself.

Fixes: 54d792f257c6 ("net: dsa: Centralise global and port setup code into mv88e6xxx.")
Signed-off-by: Steffen Bätz <steffen@innosonix.de>
Signed-off-by: Fabio Estevam <festevam@denx.de>
---
Changes since RFC:
- Use dsa_is_user_port() to decide when to set the snoop bit (Andrew).
- Reword the commit message to differentiate between IGMP snooping and an IGMP listener on
the bridge.

 drivers/net/dsa/mv88e6xxx/chip.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index b73d1d6747b7..62a126402983 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -3354,9 +3354,14 @@ static int mv88e6xxx_setup_port(struct mv88e6xxx_chip *chip, int port)
 	 * If this is the upstream port for this switch, enable
 	 * forwarding of unknown unicasts and multicasts.
 	 */
-	reg = MV88E6XXX_PORT_CTL0_IGMP_MLD_SNOOP |
-		MV88E6185_PORT_CTL0_USE_TAG | MV88E6185_PORT_CTL0_USE_IP |
+	reg = MV88E6185_PORT_CTL0_USE_TAG | MV88E6185_PORT_CTL0_USE_IP |
 		MV88E6XXX_PORT_CTL0_STATE_FORWARDING;
+	/* Forward any IPv4 IGMP or IPv6 MLD frames received
+	 * by a USER port to the CPU port to allow snooping.
+	 */
+	if (dsa_is_user_port(ds, port))
+		reg |= MV88E6XXX_PORT_CTL0_IGMP_MLD_SNOOP;
+
 	err = mv88e6xxx_port_write(chip, port, MV88E6XXX_PORT_CTL0, reg);
 	if (err)
 		return err;
-- 
2.34.1

Re: [PATCH net] net: dsa: mv88e6xxx: Enable IGMP snooping on user ports only

[Andrew Lunn]

On Wed, Mar 29, 2023 at 12:01:40PM -0300, Fabio Estevam wrote:
> From: Steffen Bätz <steffen@innosonix.de>
> 
> Do not set the MV88E6XXX_PORT_CTL0_IGMP_MLD_SNOOP bit on CPU or DSA ports.
> 
> This allows the host CPU port to be a regular IGMP listener by sending out
> IGMP Membership Reports, which would otherwise not be forwarded by the
> mv88exxx chip, but directly looped back to the CPU port itself.
> 
> Fixes: 54d792f257c6 ("net: dsa: Centralise global and port setup code into mv88e6xxx.")
> Signed-off-by: Steffen Bätz <steffen@innosonix.de>
> Signed-off-by: Fabio Estevam <festevam@denx.de>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH net] net: dsa: mv88e6xxx: Enable IGMP snooping on user ports only

[Vladimir Oltean]

On Wed, Mar 29, 2023 at 12:01:40PM -0300, Fabio Estevam wrote:
> From: Steffen Bätz <steffen@innosonix.de>
> 
> Do not set the MV88E6XXX_PORT_CTL0_IGMP_MLD_SNOOP bit on CPU or DSA ports.
> 
> This allows the host CPU port to be a regular IGMP listener by sending out
> IGMP Membership Reports, which would otherwise not be forwarded by the
> mv88exxx chip, but directly looped back to the CPU port itself.
> 
> Fixes: 54d792f257c6 ("net: dsa: Centralise global and port setup code into mv88e6xxx.")

I checked to see if the Fixes tag is correct, and... it's complicated.
That patch comes from the consolidation of multiple drivers
(mv88e6123_61_65.c, mv88e6131.c, mv88e6171.c, mv88e6352.c into what
later became the common mv88e6xxx driver. In principle, each of the
above drivers had their own buggy pre-existing logic to enable IGMP/MLD
snooping on all ports, but it seems a pointless exercise to add
individual Fixes: tags for all drivers prior to an unification process
that took place in 2015. So this gets my:

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>

Re: [PATCH net] net: dsa: mv88e6xxx: Enable IGMP snooping on user ports only

[Florian Fainelli]

On 3/29/2023 8:01 AM, Fabio Estevam wrote:
> From: Steffen Bätz <steffen@innosonix.de>
> 
> Do not set the MV88E6XXX_PORT_CTL0_IGMP_MLD_SNOOP bit on CPU or DSA ports.
> 
> This allows the host CPU port to be a regular IGMP listener by sending out
> IGMP Membership Reports, which would otherwise not be forwarded by the
> mv88exxx chip, but directly looped back to the CPU port itself.
> 
> Fixes: 54d792f257c6 ("net: dsa: Centralise global and port setup code into mv88e6xxx.")
> Signed-off-by: Steffen Bätz <steffen@innosonix.de>
> Signed-off-by: Fabio Estevam <festevam@denx.de>

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

Re: [PATCH net] net: dsa: mv88e6xxx: Enable IGMP snooping on user ports only

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Wed, 29 Mar 2023 12:01:40 -0300 you wrote:
> From: Steffen Bätz <steffen@innosonix.de>
> 
> Do not set the MV88E6XXX_PORT_CTL0_IGMP_MLD_SNOOP bit on CPU or DSA ports.
> 
> This allows the host CPU port to be a regular IGMP listener by sending out
> IGMP Membership Reports, which would otherwise not be forwarded by the
> mv88exxx chip, but directly looped back to the CPU port itself.
> 
> [...]

Here is the summary with links:
  - [net] net: dsa: mv88e6xxx: Enable IGMP snooping on user ports only
    https://git.kernel.org/netdev/net/c/7bcad0f0e6fb

You are awesome, thank you!
-- 
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