From 5ba017f9efef3cf65cc60005aae4cbbf70b9b2b8 Mon Sep 17 00:00:00 2001 From: Sandeep Sondagar Date: Sun, 9 Aug 2026 21:31:41 +0530 Subject: [PATCH] net: phylink: treat PSGMII as an inband capable interface PSGMII (the Qualcomm 5-port SGMII) conveys the link negotiation result from the PHY back to the MAC through per-channel in-band SGMII words, exactly like SGMII and QSGMII. However, PHY_INTERFACE_MODE_PSGMII is missing from phylink_get_inband_type(), so phylink reports INBAND_NONE for it and phylink_pcs_neg_mode() falls back to PHYLINK_PCS_NEG_NONE. The PCS is then programmed in force mode and its control-register speed bits (which default to 1000base) are used, so a slower copper link - e.g. 100base-T - is reported as 1Gbps and cannot pass traffic. Classify PSGMII alongside SGMII and QSGMII as INBAND_CISCO_SGMII so the PCS negotiates in-band and the resolved link speed comes from the PHY in-band word. Also add PSGMII to the generic clause 22 PCS helper functions which handle the SGMII in-band word. Without this, a PCS using these helpers would still fall through to the default handling and force the link state to false in phylink_mii_c22_pcs_decode_state(), fail to encode the SGMII advertisement, and get rejected by phylink_get_link_timer_ns(). Signed-off-by: Sandeep Sondagar Reviewed-by: Nicolai Buchwitz Link: https://patch.msgid.link/20260809-phylink-psgmii-v3-1-908dcd3a9e3d@gmail.com Signed-off-by: Jakub Kicinski --- drivers/net/phy/phylink.c | 3 +++ include/linux/phylink.h | 1 + 2 files changed, 4 insertions(+) diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c index b241768edbcb..5b8e956902fb 100644 --- a/drivers/net/phy/phylink.c +++ b/drivers/net/phy/phylink.c @@ -1039,6 +1039,7 @@ static enum inband_type phylink_get_inband_type(phy_interface_t interface) { switch (interface) { case PHY_INTERFACE_MODE_SGMII: + case PHY_INTERFACE_MODE_PSGMII: case PHY_INTERFACE_MODE_QSGMII: case PHY_INTERFACE_MODE_QUSGMII: case PHY_INTERFACE_MODE_USXGMII: @@ -4178,6 +4179,7 @@ void phylink_mii_c22_pcs_decode_state(struct phylink_link_state *state, break; case PHY_INTERFACE_MODE_SGMII: + case PHY_INTERFACE_MODE_PSGMII: case PHY_INTERFACE_MODE_QSGMII: if (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED) phylink_decode_sgmii_word(state, lpa); @@ -4258,6 +4260,7 @@ int phylink_mii_c22_pcs_encode_advertisement(phy_interface_t interface, adv |= ADVERTISE_1000XPSE_ASYM; return adv; case PHY_INTERFACE_MODE_SGMII: + case PHY_INTERFACE_MODE_PSGMII: case PHY_INTERFACE_MODE_QSGMII: return 0x0001; default: diff --git a/include/linux/phylink.h b/include/linux/phylink.h index 2bc0db3d52ac..1dda5c7ed5f1 100644 --- a/include/linux/phylink.h +++ b/include/linux/phylink.h @@ -791,6 +791,7 @@ static inline int phylink_get_link_timer_ns(phy_interface_t interface) { switch (interface) { case PHY_INTERFACE_MODE_SGMII: + case PHY_INTERFACE_MODE_PSGMII: case PHY_INTERFACE_MODE_QSGMII: case PHY_INTERFACE_MODE_USXGMII: case PHY_INTERFACE_MODE_10G_QXGMII: