openwrt-mirror/openwrt
1
0
Fork 0
mirror of https://github.com/openwrt/openwrt.git synced 2026-07-14 02:54:48 +04:00
Code Issues Packages Projects Releases Wiki Activity

airoha: account for L2 overhead in PPE MTU configuration

Browse Source 
The PPE egress MTU register and WAN MTU register compare against L2
frame length without FCS, as confirmed by the hardware reset value of
0x05EA (1514 = ETH_HLEN + 1500).

Account for VLAN_ETH_HLEN when programming these registers to prevent
valid VLAN-tagged frames from being incorrectly dropped by hardware.

Signed-off-by: Sayantan Nandy <sayantann11@gmail.com>
[ add commit description ]
Link: https://github.com/openwrt/openwrt/pull/23875
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
This commit is contained in:
Sayantan Nandy
2026-06-19 12:18:29 +05:30
committed by Christian Marangi
parent 4e2920fc08
commit d3e13c05f7
1 changed files with 79 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
target/linux/airoha/patches-6.18/920-16-net-airoha-Account-for-L2-overhead-in-PPE-MTU-configuration.patch
+79
View File
@@ -0,0 +1,79 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Sayantan Nandy <sayantann11@gmail.com>
Date: Thu, 19 Jun 2026 12:00:00 +0530
Subject: [PATCH] net: airoha: Account for L2 overhead in PPE MTU configuration
The PPE egress MTU register and WAN MTU register compare against L2
frame length without FCS, as confirmed by the hardware reset value of
0x05EA (1514 = ETH_HLEN + 1500).
Account for VLAN_ETH_HLEN when programming these registers to prevent
valid VLAN-tagged frames from being incorrectly dropped by hardware.
Rename the local variable from 'mtu' to 'len' in airoha_ppe_set_mtu()
since it now represents a frame length rather than an L3 MTU value.
Fixes: 99e204d255c9 ("net: airoha: Rework MTU configuration")
Signed-off-by: Sayantan Nandy <sayantann11@gmail.com>
---
drivers/net/ethernet/airoha/airoha_eth.c | 2 +-
drivers/net/ethernet/airoha/airoha_ppe.c | 7 ++++---
2 files changed, 5 insertions(+), 4 deletions(-)
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -8,6 +8,7 @@
#include <linux/of_reserved_mem.h>
#include <linux/platform_device.h>
#include <linux/tcp.h>
+#include <linux/if_vlan.h>
#include <linux/pcs/pcs.h>
#include <linux/u64_stats_sync.h>
#include <net/dst_metadata.h>
@@ -2115,7 +2116,7 @@ static void airoha_dev_set_mtu(struct ne
if (!airoha_is_lan_gdm_dev(dev))
airoha_fe_rmw(dev->eth, REG_WAN_MTU0,
WAN_MTU0_MASK,
- FIELD_PREP(WAN_MTU0_MASK, netdev->mtu));
+ FIELD_PREP(WAN_MTU0_MASK, netdev->mtu + VLAN_ETH_HLEN));
}
static int airoha_dev_open(struct net_device *netdev)
--- a/drivers/net/ethernet/airoha/airoha_ppe.c
+++ b/drivers/net/ethernet/airoha/airoha_ppe.c
@@ -10,6 +10,7 @@
#include <linux/platform_device.h>
#include <linux/rhashtable.h>
#include <net/ipv6.h>
+#include <linux/if_vlan.h>
#include <net/pkt_cls.h>
#include <net/route.h>
@@ -107,7 +108,7 @@ void airoha_ppe_set_mtu(struct airoha_gd
struct airoha_eth *eth = dev->eth;
struct airoha_qdma *qdma;
int i, ppe_id, index;
- u32 mtu = 0;
+ u32 len = 0;
qdma = airoha_qdma_deref(dev);
for (i = 0; i < ARRAY_SIZE(port->devs); i++) {
@@ -124,14 +125,15 @@ void airoha_ppe_set_mtu(struct airoha_gd
netdev = netdev_from_priv(d);
if (netif_running(netdev))
- mtu = max_t(u32, mtu, netdev->mtu);
+ len = max_t(u32, len, netdev->mtu);
}
+ len += VLAN_ETH_HLEN;
ppe_id = !airoha_is_lan_gdm_dev(dev) && airoha_ppe_is_enabled(eth, 1);
index = port->id == AIROHA_GDM4_IDX ? 7 : port->id;
airoha_fe_rmw(eth, REG_PPE_MTU(ppe_id, index),
FP_EGRESS_MTU_MASK(index),
- __field_prep(FP_EGRESS_MTU_MASK(index), mtu));
+ __field_prep(FP_EGRESS_MTU_MASK(index), len));
}
static void airoha_ppe_hw_init(struct airoha_ppe *ppe)