From a34ff932faaab80e9ec26f2cef98e896b8d09e47 Mon Sep 17 00:00:00 2001 From: Jan Leon Date: Mon, 7 Sep 2026 14:20:35 +0200 Subject: [PATCH] qualcommax: qca_ppe: fix BPDU trapping and CPU transmission The STP APP_CTRL rule uses 0x93fc for its third word. CMD occupies bits 16:15 of that word, so this selects DROP (1), not the intended REDIRECT_TO_CPU (3). Incoming BPDUs never reach the bridge protocol implementation even though ordinary traffic continues to work. Correcting only CMD exposes another issue: the 0x7f ingress port mask includes CPU port 0. CPU-originated BPDUs are then trapped back to the CPU rather than transmitted to the selected external port. Exclude the CPU and SoC-specific loopback ports, deriving the remaining mask from the port count. Use named fields for the third word so the action and port selection are explicit. On an AX3600/IPQ8074 running 6.18.44, register readback confirmed the original rule. A guarded runtime test of 0x193fc restored BPDU reception but captured locally generated BPDUs on the CPU RX path. With 0x193f4, those RX reflections disappeared and the adjacent switch received bridge protocol traffic again. Reapplying that value automatically after a reboot established RSTP with the upstream root. The patched driver also builds against the matching aarch64 kernel SDK. IPQ6018's generated mask was checked, but not tested on hardware. Fixes: 142104bb90b3 ("qualcommax: add PPE driver") Assisted-by: OpenAI Codex Signed-off-by: Jan Leon Link: https://github.com/openwrt/openwrt/pull/25063 Signed-off-by: Robert Marko --- .../files/drivers/net/ethernet/qualcomm/qca_ppe.h | 6 ++++++ .../drivers/net/ethernet/qualcomm/qca_ppe_main.c | 12 +++++++++++- 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/target/linux/qualcommax/files/drivers/net/ethernet/qualcomm/qca_ppe.h b/target/linux/qualcommax/files/drivers/net/ethernet/qualcomm/qca_ppe.h index bc31b61486..5e526f5dc5 100644 --- a/target/linux/qualcommax/files/drivers/net/ethernet/qualcomm/qca_ppe.h +++ b/target/linux/qualcommax/files/drivers/net/ethernet/qualcomm/qca_ppe.h @@ -276,6 +276,12 @@ #define PPE_RFDB_TBL(idx) (PPE_L2_BASE + 0x1000 + (idx) * 0x8) #define PPE_APP_CTRL(idx) (PPE_L2_BASE + 0x1400 + (idx) * 0x10) +/* Fields in the third 32-bit word of APP_CTRL. */ +#define PPE_APP_CTRL_PORT_BITMAP_EN BIT(2) +#define PPE_APP_CTRL_PORT_BITMAP GENMASK(10, 3) +#define PPE_APP_CTRL_STP_BYPASS BIT(12) +#define PPE_APP_CTRL_CMD GENMASK(16, 15) +#define PPE_APP_CTRL_REDIRECT_CPU 3 #define PPE_VSI_TBL(vsi) (PPE_L2_BASE + 0x1800 + (vsi) * 0x10) #define PPE_VSI_TBL_MEMBER GENMASK(7, 0) diff --git a/target/linux/qualcommax/files/drivers/net/ethernet/qualcomm/qca_ppe_main.c b/target/linux/qualcommax/files/drivers/net/ethernet/qualcomm/qca_ppe_main.c index e6d546762e..6170963089 100644 --- a/target/linux/qualcommax/files/drivers/net/ethernet/qualcomm/qca_ppe_main.c +++ b/target/linux/qualcommax/files/drivers/net/ethernet/qualcomm/qca_ppe_main.c @@ -1683,6 +1683,12 @@ static void ppe_mac_hw_init(struct qca_ppe_priv *priv) static void ppe_ctrlpkt_init(struct qca_ppe_priv *priv) { + u32 ports; + + /* Trap external BPDUs, but let CPU-originated BPDUs reach the wire. */ + ports = GENMASK(priv->data->num_ports - 1, 0) & + ~(BIT(QCA_PPE_CPU_PORT) | BIT(priv->data->loopback_port)); + /* RFDB_TBL[31]: STP multicast MAC 01:80:c2:00:00:00 */ regmap_write(priv->regmap, PPE_RFDB_TBL(31), 0xc2000000); regmap_write(priv->regmap, PPE_RFDB_TBL(31) + 4, 0x00010180); @@ -1690,7 +1696,11 @@ static void ppe_ctrlpkt_init(struct qca_ppe_priv *priv) /* APP_CTRL[0]: match RFDB profile 31, bypass STP, redirect to CPU */ regmap_write(priv->regmap, PPE_APP_CTRL(0), 0x00000003); regmap_write(priv->regmap, PPE_APP_CTRL(0) + 4, 0x00000002); - regmap_write(priv->regmap, PPE_APP_CTRL(0) + 8, 0x000093fc); + regmap_write(priv->regmap, PPE_APP_CTRL(0) + 8, + PPE_APP_CTRL_PORT_BITMAP_EN | + FIELD_PREP(PPE_APP_CTRL_PORT_BITMAP, ports) | + PPE_APP_CTRL_STP_BYPASS | + FIELD_PREP(PPE_APP_CTRL_CMD, PPE_APP_CTRL_REDIRECT_CPU)); } static int ppe_ipq6018_mux_setup(struct qca_ppe_priv *priv)