The PPE enforces output frame size limits via per-tag-layer VLAN_MTU registers that the driver never initializes. The hardware defaults do not account for PPPoE overhead, causing the PPE to punt encapsulated frames back to the CPU instead of forwarding them. Initialize the registers at PPE start and on MTU changes using the maximum GMAC MTU. This is a conservative approximation -- the actual per-PPE requirement depends on egress path, but using the global maximum ensures the limits are never too small.
Unified · Split
| @@ -3566,12 +3566,23 @@ found: · 3565 unmodified lines | ||
| 3566 | 3566 | return NOTIFY_DONE; |
| 3567 | 3567 | } |
| 3568 | 3568 | |
| 3569 | +static int mtk_max_gmac_mtu(struct mtk_eth *eth) | |
| 3570 | +{ | |
| 3571 | + int i, max_mtu = ETH_DATA_LEN; | |
| 3572 | + | |
| 3573 | + for (i = 0; i < ARRAY_SIZE(eth->netdev); i++) | |
| 3574 | + if (eth->netdev[i] && eth->netdev[i]->mtu > max_mtu) | |
| 3575 | + max_mtu = eth->netdev[i]->mtu; | |
| 3576 | + | |
| 3577 | + return max_mtu; | |
| 3578 | +} | |
| 3579 | + | |
| 3569 | 3580 | static int mtk_open(struct net_device *dev) |
| 3570 | 3581 | { |
| 3571 | 3582 | struct mtk_mac *mac = netdev_priv(dev); |
| 3572 | 3583 | struct mtk_eth *eth = mac->hw; |
| 3573 | 3584 | struct mtk_mac *target_mac; |
| 3574 | − int i, err, ppe_num; | |
| 3585 | + int i, err, ppe_num, mtu; | |
| 3575 | 3586 | |
| 3576 | 3587 | ppe_num = eth->soc->ppe_num; |
| 3577 | 3588 | |
| @@ -3618,6 +3629,10 @@ static int mtk_open(struct net_device *dev) · 40 unmodified lines | ||
| 3618 | 3629 | mtk_gdm_config(eth, target_mac->id, gdm_config); |
| 3619 | 3630 | } |
| 3620 | 3631 | |
| 3632 | + mtu = mtk_max_gmac_mtu(eth); | |
| 3633 | + for (i = 0; i < ARRAY_SIZE(eth->ppe); i++) | |
| 3634 | + mtk_ppe_update_mtu(eth->ppe[i], mtu); | |
| 3635 | + | |
| 3621 | 3636 | napi_enable(ð->tx_napi); |
| 3622 | 3637 | napi_enable(ð->rx_napi); |
| 3623 | 3638 | mtk_tx_irq_enable(eth, MTK_TX_DONE_INT); |
| @@ -4311,6 +4326,7 @@ static int mtk_change_mtu(struct net_device *dev, int new_mtu) · 687 unmodified lines | ||
| 4311 | 4326 | int length = new_mtu + MTK_RX_ETH_HLEN; |
| 4312 | 4327 | struct mtk_mac *mac = netdev_priv(dev); |
| 4313 | 4328 | struct mtk_eth *eth = mac->hw; |
| 4329 | + int max_mtu, i; | |
| 4314 | 4330 | |
| 4315 | 4331 | if (rcu_access_pointer(eth->prog) && |
| 4316 | 4332 | length > MTK_PP_MAX_BUF_SIZE) { |
| @@ -4321,6 +4337,10 @@ static int mtk_change_mtu(struct net_device *dev, int new_mtu) · 4 unmodified lines | ||
| 4321 | 4337 | mtk_set_mcr_max_rx(mac, length); |
| 4322 | 4338 | WRITE_ONCE(dev->mtu, new_mtu); |
| 4323 | 4339 | |
| 4340 | + max_mtu = mtk_max_gmac_mtu(eth); | |
| 4341 | + for (i = 0; i < ARRAY_SIZE(eth->ppe); i++) | |
| 4342 | + mtk_ppe_update_mtu(eth->ppe[i], max_mtu); | |
| 4343 | + | |
| 4324 | 4344 | return 0; |
| 4325 | 4345 | } |
| 4326 | 4346 | |
| @@ -973,6 +973,36 @@ static void mtk_ppe_init_foe_table(struct mtk_ppe *ppe) · 972 unmodified lines | ||
| 973 | 973 | } |
| 974 | 974 | } |
| 975 | 975 | |
| 976 | +void mtk_ppe_update_mtu(struct mtk_ppe *ppe, int mtu) | |
| 977 | +{ | |
| 978 | + int base; | |
| 979 | + u32 val; | |
| 980 | + | |
| 981 | + if (!ppe) | |
| 982 | + return; | |
| 983 | + | |
| 984 | + /* The PPE checks output frame size against per-tag-layer MTU limits, | |
| 985 | + * treating PPPoE and DSA tags just like 802.1Q VLAN tags. The Linux | |
| 986 | + * device MTU already accounts for PPPoE (PPPOE_SES_HLEN) and DSA tag | |
| 987 | + * overhead, but 802.1Q VLAN tags are handled transparently without | |
| 988 | + * being reflected by the lower device MTU being increased by 4. | |
| 989 | + * Use the maximum MTU across all GMAC interfaces so that PPE output | |
| 990 | + * frame limits are sufficiently high regardless of which port a flow | |
| 991 | + * egresses through. | |
| 992 | + */ | |
| 993 | + base = ETH_HLEN + mtu; | |
| 994 | + | |
| 995 | + val = FIELD_PREP(MTK_PPE_VLAN_MTU0_NONE, base) | | |
| 996 | + FIELD_PREP(MTK_PPE_VLAN_MTU0_1TAG, base + VLAN_HLEN); | |
| 997 | + ppe_w32(ppe, MTK_PPE_VLAN_MTU0, val); | |
| 998 | + | |
| 999 | + val = FIELD_PREP(MTK_PPE_VLAN_MTU1_2TAG, | |
| 1000 | + base + 2 * VLAN_HLEN) | | |
| 1001 | + FIELD_PREP(MTK_PPE_VLAN_MTU1_3TAG, | |
| 1002 | + base + 3 * VLAN_HLEN); | |
| 1003 | + ppe_w32(ppe, MTK_PPE_VLAN_MTU1, val); | |
| 1004 | +} | |
| 1005 | + | |
| 976 | 1006 | void mtk_ppe_start(struct mtk_ppe *ppe) |
| 977 | 1007 | { |
| 978 | 1008 | u32 val; |
| @@ -346,6 +346,7 @@ struct mtk_ppe { · 345 unmodified lines | ||
| 346 | 346 | struct mtk_ppe *mtk_ppe_init(struct mtk_eth *eth, void __iomem *base, int index); |
| 347 | 347 | |
| 348 | 348 | void mtk_ppe_deinit(struct mtk_eth *eth); |
| 349 | +void mtk_ppe_update_mtu(struct mtk_ppe *ppe, int mtu); | |
| 349 | 350 | void mtk_ppe_start(struct mtk_ppe *ppe); |
| 350 | 351 | int mtk_ppe_stop(struct mtk_ppe *ppe); |
| 351 | 352 | int mtk_ppe_prepare_reset(struct mtk_ppe *ppe); |