1 files changed, 77 insertions, 0 deletions
diff --git a/drivers/net/phy/open_alliance_helpers.c b/drivers/net/phy/open_alliance_helpers.c
new file mode 100644
index 000000000000..36a70451d7da
--- /dev/null
+++ b/drivers/net/phy/open_alliance_helpers.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * open_alliance_helpers.c - OPEN Alliance specific PHY diagnostic helpers
+ *
+ * This file contains helper functions for implementing advanced diagnostic
+ * features as specified by the OPEN Alliance for automotive Ethernet PHYs.
+ * These helpers include functionality for Time Delay Reflection (TDR), dynamic
+ * channel quality assessment, and other PHY diagnostics.
+ *
+ * For more information on the specifications, refer to the OPEN Alliance
+ * documentation: https://opensig.org/automotive-ethernet-specifications/
+ * Currently following specifications are partially or fully implemented:
+ * - Advanced diagnostic features for 1000BASE-T1 automotive Ethernet PHYs.
+ *   TC12 - advanced PHY features.
+ *   https://opensig.org/wp-content/uploads/2024/03/Advanced_PHY_features_for_automotive_Ethernet_v2.0_fin.pdf
+ */
+
+#include <linux/bitfield.h>
+#include <linux/ethtool_netlink.h>
+
+#include "open_alliance_helpers.h"
+
+/**
+ * oa_1000bt1_get_ethtool_cable_result_code - Convert TDR status to ethtool
+ *					      result code
+ * @reg_value: Value read from the TDR register
+ *
+ * This function takes a register value from the HDD.TDR register and converts
+ * the TDR status to the corresponding ethtool cable test result code.
+ *
+ * Return: The appropriate ethtool result code based on the TDR status
+ */
+int oa_1000bt1_get_ethtool_cable_result_code(u16 reg_value)
+{
+	u8 tdr_status = FIELD_GET(OA_1000BT1_HDD_TDR_STATUS_MASK, reg_value);
+	u8 dist_val = FIELD_GET(OA_1000BT1_HDD_TDR_DISTANCE_MASK, reg_value);
+
+	switch (tdr_status) {
+	case OA_1000BT1_HDD_TDR_STATUS_CABLE_OK:
+		return ETHTOOL_A_CABLE_RESULT_CODE_OK;
+	case OA_1000BT1_HDD_TDR_STATUS_OPEN:
+		return ETHTOOL_A_CABLE_RESULT_CODE_OPEN;
+	case OA_1000BT1_HDD_TDR_STATUS_SHORT:
+		return ETHTOOL_A_CABLE_RESULT_CODE_SAME_SHORT;
+	case OA_1000BT1_HDD_TDR_STATUS_NOISE:
+		return ETHTOOL_A_CABLE_RESULT_CODE_NOISE;
+	default:
+		if (dist_val == OA_1000BT1_HDD_TDR_DISTANCE_RESOLUTION_NOT_POSSIBLE)
+			return ETHTOOL_A_CABLE_RESULT_CODE_RESOLUTION_NOT_POSSIBLE;
+		return ETHTOOL_A_CABLE_RESULT_CODE_UNSPEC;
+	}
+}
+EXPORT_SYMBOL_GPL(oa_1000bt1_get_ethtool_cable_result_code);
+
+/**
+ * oa_1000bt1_get_tdr_distance - Get distance to the main fault from TDR
+ *				 register value
+ * @reg_value: Value read from the TDR register
+ *
+ * This function takes a register value from the HDD.TDR register and extracts
+ * the distance to the main fault detected by the TDR feature. The distance is
+ * measured in centimeters and ranges from 0 to 3100 centimeters. If the
+ * distance is not available (0x3f), the function returns -ERANGE.
+ *
+ * Return: The distance to the main fault in centimeters, or -ERANGE if the
+ * resolution is not possible.
+ */
+int oa_1000bt1_get_tdr_distance(u16 reg_value)
+{
+	u8 dist_val = FIELD_GET(OA_1000BT1_HDD_TDR_DISTANCE_MASK, reg_value);
+
+	if (dist_val == OA_1000BT1_HDD_TDR_DISTANCE_RESOLUTION_NOT_POSSIBLE)
+		return -ERANGE;
+
+	return dist_val * 100;
+}
+EXPORT_SYMBOL_GPL(oa_1000bt1_get_tdr_distance);