net: nvethernet: Fix build for Linux v6.15

In Linux v6,15, a 'speed' argument was added to the phy_loopback()
function. Add a conftest test to detect this change and update the
nvethernet driver accordingly. Note that if 'speed' is set to 0 when
calling phy_loopback(), then phy_loopback() behaves the same way as it
did before this argument was added. So by default set speed to 0 for the
nvethernet driver.

JIRA LINQPJ14-47

Change-Id: I55f775e672bfa1a00c9ccbd825c82be1868b0b52
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/3330685
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: buildbot_gerritrpt <buildbot_gerritrpt@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Reviewed-by: Revanth Kumar Uppala <ruppala@nvidia.com>

drivers/net/ethernet/nvidia/nvethernet/selftests.c

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
-/* Copyright (c) 2019-2025, NVIDIA CORPORATION & AFFILIATES. All rights reserved */
+// SPDX-FileCopyrightText: Copyright (c) 2019-2025, NVIDIA CORPORATION & AFFILIATES. All rights reserved
 
 #ifndef OSI_STRIPPED_LIB
 #include "ether_linux.h"
@@ -291,7 +291,11 @@ static int ether_test_phy_loopback(struct ether_priv_data *pdata)
 	if (!pdata->phydev)
 		return -ENODEV;
 
+#if defined(NV_PHY_LOOPBACK_HAS_SPEED_ARG) /* Linux v6.15 */
+	ret = phy_loopback(pdata->phydev, true, 0);
+#else
 	ret = phy_loopback(pdata->phydev, true);
+#endif
 	if (ret != 0 && ret != -EBUSY)
 		return ret;
 
@@ -397,7 +401,11 @@ void ether_selftest_run(struct net_device *dev,
 		case ETHER_LOOPBACK_PHY:
 			ret = -EOPNOTSUPP;
 			if (dev->phydev)
+#if defined(NV_PHY_LOOPBACK_HAS_SPEED_ARG) /* Linux v6.15 */
+				ret = phy_loopback(dev->phydev, true, 0);
+#else
 				ret = phy_loopback(dev->phydev, true);
+#endif
 			if (!ret)
 				break;
 		/* Fallthrough */
@@ -430,7 +438,11 @@ void ether_selftest_run(struct net_device *dev,
 		case ETHER_LOOPBACK_PHY:
 			ret = -EOPNOTSUPP;
 			if (dev->phydev)
+#if defined(NV_PHY_LOOPBACK_HAS_SPEED_ARG) /* Linux v6.15 */
+				ret = phy_loopback(dev->phydev, false, 0);
+#else
 				ret = phy_loopback(dev->phydev, false);
+#endif
 			if (!ret)
 				break;
 		/* Fallthrough */

scripts/conftest/Makefile

@@ -193,6 +193,7 @@ NV_CONFTEST_FUNCTION_COMPILE_TESTS += pci_epf_alloc_space_has_epc_features_arg
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += pci_epf_driver_struct_probe_has_id_arg
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += pci_epc_irq_type_enum_present
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += pci_irq_intx
+NV_CONFTEST_FUNCTION_COMPILE_TESTS += phy_loopback_has_speed_arg
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += platform_driver_struct_remove_returns_void
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += register_shrinker_has_fmt_arg
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += shrinker_alloc

scripts/conftest/conftest.sh

@@ -8166,6 +8166,23 @@ compile_test() {
             compile_check_conftest "$CODE" "NV_PCI_IRQ_INTX" "" "types"
         ;;
 
+        phy_loopback_has_speed_arg)
+            #
+            # Determine if phy_loopback() has 'speed' argument.
+            #
+            # Commit 0d60fd50328a ("net: phy: Support speed selection for PHY
+            # loopback") add a 'speed' argument to phy_loopback() in Linux
+            # v6.15.
+            #
+            CODE="
+            #include <linux/phy.h>
+            int conftest_phy_loopback_has_speed_arg(struct phy_device *phydev) {
+                return phy_loopback(phydev, true, 0);
+            }"
+
+            compile_check_conftest "$CODE" "NV_PHY_LOOPBACK_HAS_SPEED_ARG" "" "types"
+        ;;
+
         platform_driver_struct_remove_returns_void)
             #
             # Determine if the 'platform_driver' structure 'remove' function