From 278b8a9cd448bc658ea6c6109044a2726cfe1812 Mon Sep 17 00:00:00 2001 From: Wei Fang Date: Fri, 28 Nov 2025 10:59:15 +0800 Subject: [PATCH] net: fec: ERR007885 Workaround for XDP TX path [ Upstream commit e8e032cd24dda7cceaa27bc2eb627f82843f0466 ] The ERR007885 will lead to a TDAR race condition for mutliQ when the driver sets TDAR and the UDMA clears TDAR simultaneously or in a small window (2-4 cycles). And it will cause the udma_tx and udma_tx_arbiter state machines to hang. Therefore, the commit 53bb20d1faba ("net: fec: add variable reg_desc_active to speed things up") and the commit a179aad12bad ("net: fec: ERR007885 Workaround for conventional TX") have added the workaround to fix the potential issue for the conventional TX path. Similarly, the XDP TX path should also have the potential hang issue, so add the workaround for XDP TX path. Fixes: 6d6b39f180b8 ("net: fec: add initial XDP support") Signed-off-by: Wei Fang Link: https://patch.msgid.link/20251128025915.2486943-1-wei.fang@nxp.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/ethernet/freescale/fec_main.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index d1800868c2e0..9018a7d3864f 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -3934,7 +3934,12 @@ static int fec_enet_txq_xmit_frame(struct fec_enet_private *fep, txq->bd.cur = bdp; /* Trigger transmission start */ - writel(0, txq->bd.reg_desc_active); + if (!(fep->quirks & FEC_QUIRK_ERR007885) || + !readl(txq->bd.reg_desc_active) || + !readl(txq->bd.reg_desc_active) || + !readl(txq->bd.reg_desc_active) || + !readl(txq->bd.reg_desc_active)) + writel(0, txq->bd.reg_desc_active); return 0; }