[openwrt/openwrt] realtek: pcs: cover number of links per SerDes for USXGMII

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/7cd3407fdef67e4922f73df327c97bb0a2c679e5

commit 7cd3407fdef67e4922f73df327c97bb0a2c679e5
Author: Jonas Jelonek <jelonek.jonas at gmail.com>
AuthorDate: Fri Jan 2 16:30:16 2026 +0000

    realtek: pcs: cover number of links per SerDes for USXGMII
    
    A SerDes may supply multiple ports and depending on that number,
    different hardware modes need to be used. While there are corresponding
    modes in the kernel in some cases (e.g. USXGMII with 4 2.5G ports aka
    10G-QXGMII), this doesn't always map to Realtek hardware modes. Use the
    previously added link number accounting for that.
    
    An obvious example of this is the SerDes on XGS12xx-12 switches which
    is connected to an octa-PHY. This runs Realtek proprietary XSGMII mode
    (10G-pumped SGMII interface) for which there is no corresponding mode
    in the kernel.
    
    Signed-off-by: Jonas Jelonek <jelonek.jonas at gmail.com>
    Link: https://github.com/openwrt/openwrt/pull/21365
    Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 .../linux/realtek/files-6.12/drivers/net/pcs/pcs-rtl-otto.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/target/linux/realtek/files-6.12/drivers/net/pcs/pcs-rtl-otto.c b/target/linux/realtek/files-6.12/drivers/net/pcs/pcs-rtl-otto.c
index da11b7bafe..bd19bd5fb2 100644
--- a/target/linux/realtek/files-6.12/drivers/net/pcs/pcs-rtl-otto.c
+++ b/target/linux/realtek/files-6.12/drivers/net/pcs/pcs-rtl-otto.c
@@ -285,6 +285,8 @@ static int rtpcs_sds_determine_hw_mode(struct rtpcs_serdes *sds,
                                        phy_interface_t if_mode,
                                        enum rtpcs_sds_mode *hw_mode)
 {
+	u8 n_links = sds->num_of_links;
+
 	switch (if_mode) {
 	case PHY_INTERFACE_MODE_NA:
 		*hw_mode = RTPCS_SDS_MODE_OFF;
@@ -308,8 +310,15 @@ static int rtpcs_sds_determine_hw_mode(struct rtpcs_serdes *sds,
 		*hw_mode = RTPCS_SDS_MODE_QSGMII;
 		break;
 	case PHY_INTERFACE_MODE_USXGMII:
-		/* TODO: set this depending on number of links on SerDes */
-		*hw_mode = RTPCS_SDS_MODE_USXGMII_10GSXGMII;
+		if (n_links == 1)
+			*hw_mode = RTPCS_SDS_MODE_USXGMII_10GSXGMII;
+		else if (n_links == 2)
+			*hw_mode = RTPCS_SDS_MODE_USXGMII_10GDXGMII;
+		else if (n_links <= 4)
+			*hw_mode = RTPCS_SDS_MODE_USXGMII_10GQXGMII;
+		else if (n_links <= 8)
+			*hw_mode = RTPCS_SDS_MODE_XSGMII;
+
 		break;
 	case PHY_INTERFACE_MODE_10G_QXGMII:
 		*hw_mode = RTPCS_SDS_MODE_USXGMII_10GQXGMII;