From fa1a8457b8581725ae237efefb2358eddd7e05c9 Mon Sep 17 00:00:00 2001 From: Wei Fang Date: Fri, 21 Aug 2026 14:41:40 +0800 Subject: [PATCH] net: enetc: restore RX ring congestion mode for ENETC v4 ENETC v4 has the same problem as ENETC v1: the RX BD ring congestion mode (CM) is only configured in the phylink .mac_link_up() callback, so it is cleared when enetc_reconfigure() rebuilds the RX BD rings at runtime (for example when enabling or disabling PTP RX hardware timestamping) without a link status change, and it is never restored. As a result, the MAC can no longer generate PAUSE frames on ingress congestion and flow control stops working. Fix it in the same way as ENETC v1. Track the desired CM state in the software flag ENETC_RXBDR_CM. Route enetc4_set_tx_pause() through the shared helper enetc_set_congestion_mode(), which sets or clears the flag according to tx_pause and updates the ENETC_RBMR_CM bit under si->gen_lock. When the RX BD rings are (re)enabled, enetc_enable_rxbdr() consults this flag and restores the CM bit accordingly, so flow control survives ring reconfiguration even when the link status does not change. Fixes: f5b9a1cde0a2 ("net: enetc: add PTP synchronization support for ENETC v4") Signed-off-by: Wei Fang Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260821064140.1315611-3-wei.fang@oss.nxp.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/freescale/enetc/enetc4_pf.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/freescale/enetc/enetc4_pf.c b/drivers/net/ethernet/freescale/enetc/enetc4_pf.c index fcfbabb29d22..9bb1004548ab 100644 --- a/drivers/net/ethernet/freescale/enetc/enetc4_pf.c +++ b/drivers/net/ethernet/freescale/enetc/enetc4_pf.c @@ -718,22 +718,14 @@ static void enetc4_set_rx_pause(struct enetc_pf *pf, bool rx_pause) enetc_port_mac_wr(si, ENETC4_PM_CMD_CFG(0), val); } -static void enetc4_set_tx_pause(struct enetc_pf *pf, int num_rxbdr, bool tx_pause) +static void enetc4_set_tx_pause(struct enetc_pf *pf, bool tx_pause) { + struct enetc_ndev_priv *priv = netdev_priv(pf->si->ndev); u32 pause_off_thresh = 0, pause_on_thresh = 0; u32 init_quanta = 0, refresh_quanta = 0; struct enetc_hw *hw = &pf->si->hw; - u32 rbmr, old_rbmr; - int i; - for (i = 0; i < num_rxbdr; i++) { - old_rbmr = enetc_rxbdr_rd(hw, i, ENETC_RBMR); - rbmr = u32_replace_bits(old_rbmr, tx_pause ? 1 : 0, ENETC_RBMR_CM); - if (rbmr == old_rbmr) - continue; - - enetc_rxbdr_wr(hw, i, ENETC_RBMR, rbmr); - } + enetc_set_congestion_mode(priv, tx_pause); if (tx_pause) { /* When the port first enters congestion, send a PAUSE request @@ -898,7 +890,7 @@ static void enetc4_pl_mac_link_up(struct phylink_config *config, tx_pause = false; } - enetc4_set_tx_pause(pf, priv->num_rx_rings, tx_pause); + enetc4_set_tx_pause(pf, tx_pause); enetc4_set_rx_pause(pf, rx_pause); enetc4_mac_tx_enable(pf); enetc4_mac_rx_enable(pf);