[PATCH net 0/3] mv88e6xxx: MTU fixes

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5 messages, 2 authors, 2021-09-27 · open the first message on its own page

[PATCH net 0/3] mv88e6xxx: MTU fixes

From: Andrew Lunn <andrew@lunn.ch>
Date: 2021-09-26 17:58:26 

These three patches fix MTU issues reported by 曹煜.

There are two different ways of configuring the MTU in the hardware.
The 6161 family is using the wrong method. Some of the marvell switch
enforce the MTU when the port is used for CPU/DSA, some don't.
Because of the extra header, the MTU needs increasing with this
overhead.

Andrew Lunn (3):
  dsa: mv88e6xxx: 6161: Use chip wide MAX MTU
  dsa: mv88e6xxx: Fix MTU definition
  dsa: mv88e6xxx: Include tagger overhead when setting MTU for DSA and
    CPU ports

 drivers/net/dsa/mv88e6xxx/chip.c    | 17 ++++++++++-------
 drivers/net/dsa/mv88e6xxx/chip.h    |  1 +
 drivers/net/dsa/mv88e6xxx/global1.c |  2 ++
 drivers/net/dsa/mv88e6xxx/port.c    |  2 ++
 4 files changed, 15 insertions(+), 7 deletions(-)

-- 
2.33.0

[PATCH net 1/3] dsa: mv88e6xxx: 6161: Use chip wide MAX MTU

From: Andrew Lunn <andrew@lunn.ch>
Date: 2021-09-26 17:58:20 

The datasheets suggests the 6161 uses a per port setting for jumbo
frames. Testing has however shown this is not correct, it uses the old
style chip wide MTU control. Change the ops in the 6161 structure to
reflect this.

Fixes: 1baf0fac10fb ("net: dsa: mv88e6xxx: Use chip-wide max frame size for MTU")
Reported by: 曹煜 [off-list ref]
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 8ab0be793811..86d3cab6ceef 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -3725,7 +3725,6 @@ static const struct mv88e6xxx_ops mv88e6161_ops = {
 	.port_set_ucast_flood = mv88e6352_port_set_ucast_flood,
 	.port_set_mcast_flood = mv88e6352_port_set_mcast_flood,
 	.port_set_ether_type = mv88e6351_port_set_ether_type,
-	.port_set_jumbo_size = mv88e6165_port_set_jumbo_size,
 	.port_egress_rate_limiting = mv88e6097_port_egress_rate_limiting,
 	.port_pause_limit = mv88e6097_port_pause_limit,
 	.port_disable_learn_limit = mv88e6xxx_port_disable_learn_limit,
@@ -3750,6 +3749,7 @@ static const struct mv88e6xxx_ops mv88e6161_ops = {
 	.avb_ops = &mv88e6165_avb_ops,
 	.ptp_ops = &mv88e6165_ptp_ops,
 	.phylink_validate = mv88e6185_phylink_validate,
+	.set_max_frame_size = mv88e6185_g1_set_max_frame_size,
 };
 
 static const struct mv88e6xxx_ops mv88e6165_ops = {
-- 
2.33.0

[PATCH net 2/3] dsa: mv88e6xxx: Fix MTU definition

From: Andrew Lunn <andrew@lunn.ch>
Date: 2021-09-26 17:58:23 

The MTU passed to the DSA driver is the payload size, typically 1500.
However, the switch uses the frame size when applying restrictions.
Adjust the MTU with the size of the Ethernet header and the frame
checksum. The VLAN header also needs to be included when the frame
size it per port, but not when it is global.

Fixes: 1baf0fac10fb ("net: dsa: mv88e6xxx: Use chip-wide max frame size for MTU")
Reported by: 曹煜 [off-list ref]
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/dsa/mv88e6xxx/chip.c    | 12 ++++++------
 drivers/net/dsa/mv88e6xxx/global1.c |  2 ++
 drivers/net/dsa/mv88e6xxx/port.c    |  2 ++
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 86d3cab6ceef..ed4a6d18142b 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2834,8 +2834,8 @@ static int mv88e6xxx_setup_port(struct mv88e6xxx_chip *chip, int port)
 	if (err)
 		return err;
 
-	/* Port Control 2: don't force a good FCS, set the maximum frame size to
-	 * 10240 bytes, disable 802.1q tags checking, don't discard tagged or
+	/* Port Control 2: don't force a good FCS, set the MTU size to
+	 * 10222 bytes, disable 802.1q tags checking, don't discard tagged or
 	 * untagged frames on this port, do a destination address lookup on all
 	 * received packets as usual, disable ARP mirroring and don't send a
 	 * copy of all transmitted/received frames on this port to the CPU.
@@ -2854,7 +2854,7 @@ static int mv88e6xxx_setup_port(struct mv88e6xxx_chip *chip, int port)
 		return err;
 
 	if (chip->info->ops->port_set_jumbo_size) {
-		err = chip->info->ops->port_set_jumbo_size(chip, port, 10240);
+		err = chip->info->ops->port_set_jumbo_size(chip, port, 10218);
 		if (err)
 			return err;
 	}
@@ -2944,10 +2944,10 @@ static int mv88e6xxx_get_max_mtu(struct dsa_switch *ds, int port)
 	struct mv88e6xxx_chip *chip = ds->priv;
 
 	if (chip->info->ops->port_set_jumbo_size)
-		return 10240;
+		return 10240 - VLAN_ETH_HLEN - ETH_FCS_LEN;
 	else if (chip->info->ops->set_max_frame_size)
-		return 1632;
-	return 1522;
+		return 1632 - VLAN_ETH_HLEN - ETH_FCS_LEN;
+	return 1522 - VLAN_ETH_HLEN - ETH_FCS_LEN;
 }
 
 static int mv88e6xxx_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
diff --git a/drivers/net/dsa/mv88e6xxx/global1.c b/drivers/net/dsa/mv88e6xxx/global1.c
index 815b0f681d69..5848112036b0 100644
--- a/drivers/net/dsa/mv88e6xxx/global1.c
+++ b/drivers/net/dsa/mv88e6xxx/global1.c
@@ -232,6 +232,8 @@ int mv88e6185_g1_set_max_frame_size(struct mv88e6xxx_chip *chip, int mtu)
 	u16 val;
 	int err;
 
+	mtu += ETH_HLEN + ETH_FCS_LEN;
+
 	err = mv88e6xxx_g1_read(chip, MV88E6XXX_G1_CTL1, &val);
 	if (err)
 		return err;
diff --git a/drivers/net/dsa/mv88e6xxx/port.c b/drivers/net/dsa/mv88e6xxx/port.c
index f77e2ee64a60..451028c57af8 100644
--- a/drivers/net/dsa/mv88e6xxx/port.c
+++ b/drivers/net/dsa/mv88e6xxx/port.c
@@ -1277,6 +1277,8 @@ int mv88e6165_port_set_jumbo_size(struct mv88e6xxx_chip *chip, int port,
 	u16 reg;
 	int err;
 
+	size += VLAN_ETH_HLEN + ETH_FCS_LEN;
+
 	err = mv88e6xxx_port_read(chip, port, MV88E6XXX_PORT_CTL2, &reg);
 	if (err)
 		return err;
-- 
2.33.0

[PATCH net 3/3] dsa: mv88e6xxx: Include tagger overhead when setting MTU for DSA and CPU ports

From: Andrew Lunn <andrew@lunn.ch>
Date: 2021-09-26 17:58:25 

Same members of the Marvell Ethernet switches impose MTU restrictions
on ports used for connecting to the CPU or another switch for DSA. If
the MTU is set too low, tagged frames will be discarded. Ensure the
worst case tagger overhead is included in setting the MTU for DSA and
CPU ports.

Fixes: 1baf0fac10fb ("net: dsa: mv88e6xxx: Use chip-wide max frame size for MTU")
Reported by: 曹煜 [off-list ref]
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 9 ++++++---
 drivers/net/dsa/mv88e6xxx/chip.h | 1 +
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index ed4a6d18142b..03744d1c43fc 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2944,10 +2944,10 @@ static int mv88e6xxx_get_max_mtu(struct dsa_switch *ds, int port)
 	struct mv88e6xxx_chip *chip = ds->priv;
 
 	if (chip->info->ops->port_set_jumbo_size)
-		return 10240 - VLAN_ETH_HLEN - ETH_FCS_LEN;
+		return 10240 - VLAN_ETH_HLEN - EDSA_HLEN - ETH_FCS_LEN;
 	else if (chip->info->ops->set_max_frame_size)
-		return 1632 - VLAN_ETH_HLEN - ETH_FCS_LEN;
-	return 1522 - VLAN_ETH_HLEN - ETH_FCS_LEN;
+		return 1632 - VLAN_ETH_HLEN - EDSA_HLEN - ETH_FCS_LEN;
+	return 1522 - VLAN_ETH_HLEN - EDSA_HLEN - ETH_FCS_LEN;
 }
 
 static int mv88e6xxx_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
@@ -2955,6 +2955,9 @@ static int mv88e6xxx_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
 	struct mv88e6xxx_chip *chip = ds->priv;
 	int ret = 0;
 
+	if (dsa_is_dsa_port(ds, port) || dsa_is_cpu_port(ds, port))
+		new_mtu += EDSA_HLEN;
+
 	mv88e6xxx_reg_lock(chip);
 	if (chip->info->ops->port_set_jumbo_size)
 		ret = chip->info->ops->port_set_jumbo_size(chip, port, new_mtu);
diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index 675b1f3e43b7..59f316cc8583 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -18,6 +18,7 @@
 #include <linux/timecounter.h>
 #include <net/dsa.h>
 
+#define EDSA_HLEN		8
 #define MV88E6XXX_N_FID		4096
 
 /* PVT limits for 4-bit port and 5-bit switch */
-- 
2.33.0

Re: [PATCH net 0/3] mv88e6xxx: MTU fixes

From: patchwork-bot+netdevbpf@kernel.org
Date: 2021-09-27 12:40:09 

Hello:

This series was applied to netdev/net.git (refs/heads/master):

On Sun, 26 Sep 2021 19:41:23 +0200 you wrote:
These three patches fix MTU issues reported by 曹煜.

There are two different ways of configuring the MTU in the hardware.
The 6161 family is using the wrong method. Some of the marvell switch
enforce the MTU when the port is used for CPU/DSA, some don't.
Because of the extra header, the MTU needs increasing with this
overhead.

[...]
Here is the summary with links:
  - [net,1/3] dsa: mv88e6xxx: 6161: Use chip wide MAX MTU
    https://git.kernel.org/netdev/net/c/fe23036192c9
  - [net,2/3] dsa: mv88e6xxx: Fix MTU definition
    https://git.kernel.org/netdev/net/c/b92ce2f54c0f
  - [net,3/3] dsa: mv88e6xxx: Include tagger overhead when setting MTU for DSA and CPU ports
    https://git.kernel.org/netdev/net/c/b9c587fed61c

You are awesome, thank you!
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