[PATCH net-next 02/10] net: dsa: microchip: split port_max_mtu() implementation
From: Bastien Curutchet
Date: Thu Jul 02 2026 - 05:29:50 EST
From: Vladimir Oltean <vladimir.oltean@xxxxxxx>
ksz_max_mtu() is a bit cluttered. It would be good for developers and
reviewers if they didn't need to look at a common function for hardware
they likely don't have, and which is vastly different, when they are
interested in only a specific chip.
Benefit from the fact that all families listed here have their own
dsa_switch_ops, and provide separate implementations for the
port_max_mtu() method.
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Signed-off-by: Bastien Curutchet (Schneider Electric) <bastien.curutchet@xxxxxxxxxxx>
---
drivers/net/dsa/microchip/ksz8.c | 16 ++++++++++++---
drivers/net/dsa/microchip/ksz9477.c | 7 ++++++-
drivers/net/dsa/microchip/ksz9477.h | 1 +
drivers/net/dsa/microchip/ksz_common.c | 34 --------------------------------
drivers/net/dsa/microchip/ksz_common.h | 2 --
drivers/net/dsa/microchip/lan937x_main.c | 2 +-
6 files changed, 21 insertions(+), 41 deletions(-)
diff --git a/drivers/net/dsa/microchip/ksz8.c b/drivers/net/dsa/microchip/ksz8.c
index c351179f6a60..2b4720c4c87e 100644
--- a/drivers/net/dsa/microchip/ksz8.c
+++ b/drivers/net/dsa/microchip/ksz8.c
@@ -202,6 +202,16 @@ static int ksz87xx_change_mtu(struct dsa_switch *ds, int port, int mtu)
return ksz_rmw8(dev, REG_SW_CTRL_2, SW_LEGAL_PACKET_DISABLE, ctrl2);
}
+static int ksz87xx_max_mtu(struct dsa_switch *ds, int port)
+{
+ return KSZ8795_HUGE_PACKET_SIZE - VLAN_ETH_HLEN - ETH_FCS_LEN;
+}
+
+static int ksz88xx_max_mtu(struct dsa_switch *ds, int port)
+{
+ return KSZ8863_HUGE_PACKET_SIZE - VLAN_ETH_HLEN - ETH_FCS_LEN;
+}
+
static int ksz8_port_queue_split(struct ksz_device *dev, int port, int queues)
{
u8 mask_4q, mask_2q;
@@ -2541,7 +2551,7 @@ const struct dsa_switch_ops ksz8463_switch_ops = {
.get_stats64 = ksz_get_stats64,
.get_pause_stats = ksz_get_pause_stats,
.port_change_mtu = ksz88xx_change_mtu,
- .port_max_mtu = ksz_max_mtu,
+ .port_max_mtu = ksz88xx_max_mtu,
.suspend = ksz_suspend,
.resume = ksz_resume,
.get_ts_info = ksz_get_ts_info,
@@ -2591,7 +2601,7 @@ const struct dsa_switch_ops ksz87xx_switch_ops = {
.get_stats64 = ksz_get_stats64,
.get_pause_stats = ksz_get_pause_stats,
.port_change_mtu = ksz87xx_change_mtu,
- .port_max_mtu = ksz_max_mtu,
+ .port_max_mtu = ksz87xx_max_mtu,
.suspend = ksz_suspend,
.resume = ksz_resume,
.get_ts_info = ksz_get_ts_info,
@@ -2642,7 +2652,7 @@ const struct dsa_switch_ops ksz88xx_switch_ops = {
.get_stats64 = ksz_get_stats64,
.get_pause_stats = ksz_get_pause_stats,
.port_change_mtu = ksz88xx_change_mtu,
- .port_max_mtu = ksz_max_mtu,
+ .port_max_mtu = ksz88xx_max_mtu,
.get_wol = ksz_get_wol,
.set_wol = ksz_set_wol,
.suspend = ksz_suspend,
diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index f3f0c98dfb5a..0b08d2175f17 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -60,6 +60,11 @@ static int ksz9477_change_mtu(struct dsa_switch *ds, int port, int mtu)
REG_SW_MTU_MASK, frame_size);
}
+int ksz9477_max_mtu(struct dsa_switch *ds, int port)
+{
+ return KSZ9477_MAX_FRAME_SIZE - VLAN_ETH_HLEN - ETH_FCS_LEN;
+}
+
static int ksz9477_wait_vlan_ctrl_ready(struct ksz_device *dev)
{
unsigned int val;
@@ -2098,7 +2103,7 @@ const struct dsa_switch_ops ksz9477_switch_ops = {
.get_stats64 = ksz_get_stats64,
.get_pause_stats = ksz_get_pause_stats,
.port_change_mtu = ksz9477_change_mtu,
- .port_max_mtu = ksz_max_mtu,
+ .port_max_mtu = ksz9477_max_mtu,
.get_wol = ksz_get_wol,
.set_wol = ksz_set_wol,
.suspend = ksz_suspend,
diff --git a/drivers/net/dsa/microchip/ksz9477.h b/drivers/net/dsa/microchip/ksz9477.h
index 92a1d889224d..25b74d0af6c5 100644
--- a/drivers/net/dsa/microchip/ksz9477.h
+++ b/drivers/net/dsa/microchip/ksz9477.h
@@ -21,6 +21,7 @@ void ksz9477_freeze_mib(struct ksz_device *dev, int port, bool freeze);
void ksz9477_port_init_cnt(struct ksz_device *dev, int port);
int ksz9477_port_vlan_filtering(struct dsa_switch *ds, int port,
bool flag, struct netlink_ext_ack *extack);
+int ksz9477_max_mtu(struct dsa_switch *ds, int port);
int ksz9477_port_vlan_add(struct dsa_switch *ds, int port,
const struct switchdev_obj_port_vlan *vlan,
struct netlink_ext_ack *extack);
diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index d1726778bb48..686bdbfe8b6a 100644
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -2984,40 +2984,6 @@ int ksz_port_bridge_flags(struct dsa_switch *ds, int port,
return 0;
}
-int ksz_max_mtu(struct dsa_switch *ds, int port)
-{
- struct ksz_device *dev = ds->priv;
-
- switch (dev->chip_id) {
- case KSZ8795_CHIP_ID:
- case KSZ8794_CHIP_ID:
- case KSZ8765_CHIP_ID:
- return KSZ8795_HUGE_PACKET_SIZE - VLAN_ETH_HLEN - ETH_FCS_LEN;
- case KSZ8463_CHIP_ID:
- case KSZ88X3_CHIP_ID:
- case KSZ8864_CHIP_ID:
- case KSZ8895_CHIP_ID:
- return KSZ8863_HUGE_PACKET_SIZE - VLAN_ETH_HLEN - ETH_FCS_LEN;
- case KSZ8563_CHIP_ID:
- case KSZ8567_CHIP_ID:
- case KSZ9477_CHIP_ID:
- case KSZ9563_CHIP_ID:
- case KSZ9567_CHIP_ID:
- case KSZ9893_CHIP_ID:
- case KSZ9896_CHIP_ID:
- case KSZ9897_CHIP_ID:
- case LAN9370_CHIP_ID:
- case LAN9371_CHIP_ID:
- case LAN9372_CHIP_ID:
- case LAN9373_CHIP_ID:
- case LAN9374_CHIP_ID:
- case LAN9646_CHIP_ID:
- return KSZ9477_MAX_FRAME_SIZE - VLAN_ETH_HLEN - ETH_FCS_LEN;
- }
-
- return -EOPNOTSUPP;
-}
-
int ksz_set_mac_eee(struct dsa_switch *ds, int port,
struct ethtool_keee *e)
{
diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index b4a5673ba365..f276f2452684 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -443,8 +443,6 @@ void ksz_phylink_mac_link_down(struct phylink_config *config,
unsigned int mode,
phy_interface_t interface);
-int ksz_max_mtu(struct dsa_switch *ds, int port);
-
int ksz_set_mac_eee(struct dsa_switch *ds, int port,
struct ethtool_keee *e);
diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c
index 8eb5337b0c10..f060fbc4c4f4 100644
--- a/drivers/net/dsa/microchip/lan937x_main.c
+++ b/drivers/net/dsa/microchip/lan937x_main.c
@@ -983,7 +983,7 @@ const struct dsa_switch_ops lan937x_switch_ops = {
.get_stats64 = ksz_get_stats64,
.get_pause_stats = ksz_get_pause_stats,
.port_change_mtu = lan937x_change_mtu,
- .port_max_mtu = ksz_max_mtu,
+ .port_max_mtu = ksz9477_max_mtu,
.suspend = ksz_suspend,
.resume = ksz_resume,
.get_ts_info = ksz_get_ts_info,
--
2.54.0