[PATCH v2 06/10] net: pcs: xpcs: add ANRESTART support for SGMII link recovery
From: Coia Prant <hidden>
Date: 2026-08-01 14:24:11
Also in:
linux-arm-kernel, linux-devicetree, linux-phy, linux-renesas-soc, linux-rockchip, lkml
Subsystem:
ethernet phy library, networking drivers, synopsys designware ethernet xpcs driver, the rest · Maintainers:
Andrew Lunn, Heiner Kallweit, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
On some hardware using the DesignWare XPCS IP (e.g., RK3568 MAC side SGMII), the PCS does not automatically restart auto-negotiation when the link goes down and comes back up. Without an explicit ANRESTART, the link stays down forever. Add BMCR_ANRESTART in two places: 1. In xpcs_config_aneg_c37_sgmii(), when starting AN, set ANRESTART alongside ANENABLE to initiate a fresh negotiation. 2. In xpcs_get_state_c37_sgmii(), when link is down and AN completion is detected, clear the interrupt and trigger ANRESTART to restart the negotiation process. This change has been verified on: - RK3568 (Photonicat board) - Wangxun NICs (no regression) Tested-by: Jiawen Wu <jiawenwu@trustnetic.com> Signed-off-by: Coia Prant <redacted> --- drivers/net/pcs/pcs-xpcs.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/drivers/net/pcs/pcs-xpcs.c b/drivers/net/pcs/pcs-xpcs.c
index 0337e2bcc0125..28e98449e8ac2 100644
--- a/drivers/net/pcs/pcs-xpcs.c
+++ b/drivers/net/pcs/pcs-xpcs.c@@ -816,9 +816,14 @@ static int xpcs_config_aneg_c37_sgmii(struct dw_xpcs *xpcs, if (ret < 0) return ret; + /* Clear CL37 AN complete status */ + ret = xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_INTR_STS, 0); + if (ret < 0) + return ret; + if (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED) ret = xpcs_write(xpcs, MDIO_MMD_VEND2, MII_BMCR, - mdio_ctrl | BMCR_ANENABLE); + mdio_ctrl | BMCR_ANENABLE | BMCR_ANRESTART); return ret; }
@@ -1089,14 +1094,18 @@ static int xpcs_get_state_c37_sgmii(struct dw_xpcs *xpcs, state->duplex = DUPLEX_FULL; else state->duplex = DUPLEX_HALF; - return 0; } - /* Clear AN complete status or interrupt */ - if (state->an_complete) + if (state->an_complete) { + /* Clear AN complete status or interrupt */ xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_INTR_STS, 0); + /* Initiate the next round of AN */ + xpcs_modify(xpcs, MDIO_MMD_VEND2, MII_BMCR, BMCR_ANRESTART, + BMCR_ANRESTART); + } + return 0; }
--
2.47.3