phy: Add Open Alliance helpers for the PHY framework

Introduce helper functions specific to Open Alliance diagnostics,
integrating them into the PHY framework. Currently, these helpers
are limited to 1000BaseT1 specific TDR functionality.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://patch.msgid.link/20240812073046.1728288-2-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 7fddc8306d8226be2d628289f8e3302d31b2f6a9..874422e530ff07e80fd08f30f9155d8a93791838 100644 (file)
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -44,6 +44,9 @@ config LED_TRIGGER_PHY
                <Speed in megabits>Mbps OR <Speed in gigabits>Gbps OR link
                for any speed known to the PHY.
 
+config OPEN_ALLIANCE_HELPERS
+       bool
+
 config PHYLIB_LEDS
        def_bool OF
        depends on LEDS_CLASS=y || LEDS_CLASS=PHYLIB

diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 202ed7f450da6f9c9286b1b00e5c27cc8dc596a9..f086a606a87e90ac2713181de11783449c774bde 100644 (file)
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -22,6 +22,7 @@ endif
 obj-$(CONFIG_MDIO_DEVRES)      += mdio_devres.o
 libphy-$(CONFIG_SWPHY)         += swphy.o
 libphy-$(CONFIG_LED_TRIGGER_PHY)       += phy_led_triggers.o
+libphy-$(CONFIG_OPEN_ALLIANCE_HELPERS) += open_alliance_helpers.o
 
 obj-$(CONFIG_PHYLINK)          += phylink.o
 obj-$(CONFIG_PHYLIB)           += libphy.o

diff --git a/drivers/net/phy/open_alliance_helpers.c b/drivers/net/phy/open_alliance_helpers.c
new file mode 100644 (file)
index 0000000..36a7045
--- /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);

diff --git a/drivers/net/phy/open_alliance_helpers.h b/drivers/net/phy/open_alliance_helpers.h
new file mode 100644 (file)
index 0000000..8b7d97b
--- /dev/null
+++ b/drivers/net/phy/open_alliance_helpers.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef OPEN_ALLIANCE_HELPERS_H
+#define OPEN_ALLIANCE_HELPERS_H
+
+/*
+ * These defines reflect the TDR (Time Delay Reflection) diagnostic feature
+ * for 1000BASE-T1 automotive Ethernet PHYs as specified by the OPEN Alliance.
+ *
+ * The register values are part of the HDD.TDR register, which provides
+ * information about the cable status and faults. The exact register offset
+ * is device-specific and should be provided by the driver.
+ */
+#define OA_1000BT1_HDD_TDR_ACTIVATION_MASK             GENMASK(1, 0)
+#define OA_1000BT1_HDD_TDR_ACTIVATION_OFF              1
+#define OA_1000BT1_HDD_TDR_ACTIVATION_ON               2
+
+#define OA_1000BT1_HDD_TDR_STATUS_MASK                 GENMASK(7, 4)
+#define OA_1000BT1_HDD_TDR_STATUS_SHORT                        3
+#define OA_1000BT1_HDD_TDR_STATUS_OPEN                 6
+#define OA_1000BT1_HDD_TDR_STATUS_NOISE                        5
+#define OA_1000BT1_HDD_TDR_STATUS_CABLE_OK             7
+#define OA_1000BT1_HDD_TDR_STATUS_TEST_IN_PROGRESS     8
+#define OA_1000BT1_HDD_TDR_STATUS_TEST_NOT_POSSIBLE    13
+
+/*
+ * OA_1000BT1_HDD_TDR_DISTANCE_MASK:
+ * This mask is used to extract the distance to the first/main fault
+ * detected by the TDR feature. Each bit represents an approximate distance
+ * of 1 meter, ranging from 0 to 31 meters. The exact interpretation of the
+ * bits may vary, but generally:
+ * 000000 = no error
+ * 000001 = error about 0-1m away
+ * 000010 = error between 1-2m away
+ * ...
+ * 011111 = error about 30-31m away
+ * 111111 = resolution not possible / out of distance
+ */
+#define OA_1000BT1_HDD_TDR_DISTANCE_MASK                       GENMASK(13, 8)
+#define OA_1000BT1_HDD_TDR_DISTANCE_NO_ERROR                   0
+#define OA_1000BT1_HDD_TDR_DISTANCE_RESOLUTION_NOT_POSSIBLE    0x3f
+
+int oa_1000bt1_get_ethtool_cable_result_code(u16 reg_value);
+int oa_1000bt1_get_tdr_distance(u16 reg_value);
+
+#endif /* OPEN_ALLIANCE_HELPERS_H */
+