[PATCH net-next v5 1/3] ethtool: Add new result codes for TDR diagnostics

[PATCH net-next v5 1/3] ethtool: Add new result codes for TDR diagnostics

[Oleksij Rempel]

Add new result codes to support TDR diagnostics in preparation for
Open Alliance 1000BaseT1 TDR support:

- ETHTOOL_A_CABLE_RESULT_CODE_NOISE: TDR not possible due to high noise
  level.
- ETHTOOL_A_CABLE_RESULT_CODE_RESOLUTION_NOT_POSSIBLE: TDR resolution not
  possible / out of distance.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 include/uapi/linux/ethtool_netlink.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 6d5bdcc67631a..fc814c8a5ac47 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -556,6 +556,10 @@ enum {
 	 * a regular 100 Ohm cable and a part with the abnormal impedance value
 	 */
 	ETHTOOL_A_CABLE_RESULT_CODE_IMPEDANCE_MISMATCH,
+	/* TDR not possible due to high noise level */
+	ETHTOOL_A_CABLE_RESULT_CODE_NOISE,
+	/* TDR resolution not possible / out of distance */
+	ETHTOOL_A_CABLE_RESULT_CODE_RESOLUTION_NOT_POSSIBLE,
 };
 
 enum {
-- 
2.39.2

[PATCH net-next v5 2/3] phy: Add Open Alliance helpers for the PHY framework

[Oleksij Rempel]

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>
---
changes v5:
- make open_alliance_helpers.o part of libphy
changes v4:
- fix compile error for i386 and m68k
changes v3:
- make it optional
- move headers to the drivers/net/phy folder
---
 drivers/net/phy/Kconfig                 |  3 +
 drivers/net/phy/Makefile                |  1 +
 drivers/net/phy/open_alliance_helpers.c | 77 +++++++++++++++++++++++++
 drivers/net/phy/open_alliance_helpers.h | 47 +++++++++++++++
 4 files changed, 128 insertions(+)
 create mode 100644 drivers/net/phy/open_alliance_helpers.c
 create mode 100644 drivers/net/phy/open_alliance_helpers.h

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 7fddc8306d822..874422e530ff0 100644
--- 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 202ed7f450da6..f086a606a87e9 100644
--- 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
index 0000000000000..36a70451d7da0
--- /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
index 0000000000000..8b7d97bc6f186
--- /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 */
+
-- 
2.39.2

[PATCH net-next v5 3/3] net: phy: dp83tg720: Add cable testing support

[Oleksij Rempel]

Introduce cable testing support for the DP83TG720 PHY. This implementation
is based on the "DP83TG720S-Q1: Configuring for Open Alliance Specification
Compliance (Rev. B)" application note.

The feature has been tested with cables of various lengths:
- No cable: 1m till open reported.
- 5 meter cable: reported properly.
- 20 meter cable: reported as 19m.
- 40 meter cable: reported as cable ok.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
changes v3:
- select OPEN_ALLIANCE_HELPERS
changes v2:
- use open alliance specific helpers for the TDR results
---
 drivers/net/phy/Kconfig     |   1 +
 drivers/net/phy/dp83tg720.c | 154 ++++++++++++++++++++++++++++++++++++
 2 files changed, 155 insertions(+)

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 874422e530ff0..f530fcd092fe4 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -417,6 +417,7 @@ config DP83TD510_PHY
 
 config DP83TG720_PHY
 	tristate "Texas Instruments DP83TG720 Ethernet 1000Base-T1 PHY"
+	select OPEN_ALLIANCE_HELPERS
 	help
 	  The DP83TG720S-Q1 is an automotive Ethernet physical layer
 	  transceiver compliant with IEEE 802.3bp and Open Alliance
diff --git a/drivers/net/phy/dp83tg720.c b/drivers/net/phy/dp83tg720.c
index c706429b225a2..0ef4d7dba0656 100644
--- a/drivers/net/phy/dp83tg720.c
+++ b/drivers/net/phy/dp83tg720.c
@@ -3,10 +3,13 @@
  * Copyright (c) 2023 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
  */
 #include <linux/bitfield.h>
+#include <linux/ethtool_netlink.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/phy.h>
 
+#include "open_alliance_helpers.h"
+
 #define DP83TG720S_PHY_ID			0x2000a284
 
 /* MDIO_MMD_VEND2 registers */
@@ -14,6 +17,17 @@
 #define DP83TG720S_STS_MII_INT			BIT(7)
 #define DP83TG720S_LINK_STATUS			BIT(0)
 
+/* TDR Configuration Register (0x1E) */
+#define DP83TG720S_TDR_CFG			0x1e
+/* 1b = TDR start, 0b = No TDR */
+#define DP83TG720S_TDR_START			BIT(15)
+/* 1b = TDR auto on link down, 0b = Manual TDR start */
+#define DP83TG720S_CFG_TDR_AUTO_RUN		BIT(14)
+/* 1b = TDR done, 0b = TDR in progress */
+#define DP83TG720S_TDR_DONE			BIT(1)
+/* 1b = TDR fail, 0b = TDR success */
+#define DP83TG720S_TDR_FAIL			BIT(0)
+
 #define DP83TG720S_PHY_RESET			0x1f
 #define DP83TG720S_HW_RESET			BIT(15)
 
@@ -22,18 +36,155 @@
 /* Power Mode 0 is Normal mode */
 #define DP83TG720S_LPS_CFG3_PWR_MODE_0		BIT(0)
 
+/* Open Aliance 1000BaseT1 compatible HDD.TDR Fault Status Register */
+#define DP83TG720S_TDR_FAULT_STATUS		0x30f
+
+/* Register 0x0301: TDR Configuration 2 */
+#define DP83TG720S_TDR_CFG2			0x301
+
+/* Register 0x0303: TDR Configuration 3 */
+#define DP83TG720S_TDR_CFG3			0x303
+
+/* Register 0x0304: TDR Configuration 4 */
+#define DP83TG720S_TDR_CFG4			0x304
+
+/* Register 0x0405: Unknown Register */
+#define DP83TG720S_UNKNOWN_0405			0x405
+
+/* Register 0x0576: TDR Master Link Down Control */
+#define DP83TG720S_TDR_MASTER_LINK_DOWN		0x576
+
 #define DP83TG720S_RGMII_DELAY_CTRL		0x602
 /* In RGMII mode, Enable or disable the internal delay for RXD */
 #define DP83TG720S_RGMII_RX_CLK_SEL		BIT(1)
 /* In RGMII mode, Enable or disable the internal delay for TXD */
 #define DP83TG720S_RGMII_TX_CLK_SEL		BIT(0)
 
+/* Register 0x083F: Unknown Register */
+#define DP83TG720S_UNKNOWN_083F			0x83f
+
 #define DP83TG720S_SQI_REG_1			0x871
 #define DP83TG720S_SQI_OUT_WORST		GENMASK(7, 5)
 #define DP83TG720S_SQI_OUT			GENMASK(3, 1)
 
 #define DP83TG720_SQI_MAX			7
 
+/**
+ * dp83tg720_cable_test_start - Start the cable test for the DP83TG720 PHY.
+ * @phydev: Pointer to the phy_device structure.
+ *
+ * This sequence is based on the documented procedure for the DP83TG720 PHY.
+ *
+ * Returns: 0 on success, a negative error code on failure.
+ */
+static int dp83tg720_cable_test_start(struct phy_device *phydev)
+{
+	int ret;
+
+	/* Initialize the PHY to run the TDR test as described in the
+	 * "DP83TG720S-Q1: Configuring for Open Alliance Specification
+	 * Compliance (Rev. B)" application note.
+	 * Most of the registers are not documented. Some of register names
+	 * are guessed by comparing the register offsets with the DP83TD510E.
+	 */
+
+	/* Force master link down */
+	ret = phy_set_bits_mmd(phydev, MDIO_MMD_VEND2,
+			       DP83TG720S_TDR_MASTER_LINK_DOWN, 0x0400);
+	if (ret)
+		return ret;
+
+	ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, DP83TG720S_TDR_CFG2,
+			    0xa008);
+	if (ret)
+		return ret;
+
+	ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, DP83TG720S_TDR_CFG3,
+			    0x0928);
+	if (ret)
+		return ret;
+
+	ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, DP83TG720S_TDR_CFG4,
+			    0x0004);
+	if (ret)
+		return ret;
+
+	ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, DP83TG720S_UNKNOWN_0405,
+			    0x6400);
+	if (ret)
+		return ret;
+
+	ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, DP83TG720S_UNKNOWN_083F,
+			    0x3003);
+	if (ret)
+		return ret;
+
+	/* Start the TDR */
+	ret = phy_set_bits_mmd(phydev, MDIO_MMD_VEND2, DP83TG720S_TDR_CFG,
+			       DP83TG720S_TDR_START);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/**
+ * dp83tg720_cable_test_get_status - Get the status of the cable test for the
+ *                                   DP83TG720 PHY.
+ * @phydev: Pointer to the phy_device structure.
+ * @finished: Pointer to a boolean that indicates whether the test is finished.
+ *
+ * The function sets the @finished flag to true if the test is complete.
+ *
+ * Returns: 0 on success or a negative error code on failure.
+ */
+static int dp83tg720_cable_test_get_status(struct phy_device *phydev,
+					   bool *finished)
+{
+	int ret, stat;
+
+	*finished = false;
+
+	/* Read the TDR status */
+	ret = phy_read_mmd(phydev, MDIO_MMD_VEND2, DP83TG720S_TDR_CFG);
+	if (ret < 0)
+		return ret;
+
+	/* Check if the TDR test is done */
+	if (!(ret & DP83TG720S_TDR_DONE))
+		return 0;
+
+	/* Check for TDR test failure */
+	if (!(ret & DP83TG720S_TDR_FAIL)) {
+		int location;
+
+		/* Read fault status */
+		ret = phy_read_mmd(phydev, MDIO_MMD_VEND2,
+				   DP83TG720S_TDR_FAULT_STATUS);
+		if (ret < 0)
+			return ret;
+
+		/* Get fault type */
+		stat = oa_1000bt1_get_ethtool_cable_result_code(ret);
+
+		/* Determine fault location */
+		location = oa_1000bt1_get_tdr_distance(ret);
+		if (location > 0)
+			ethnl_cable_test_fault_length(phydev,
+						      ETHTOOL_A_CABLE_PAIR_A,
+						      location);
+	} else {
+		/* Active link partner or other issues */
+		stat = ETHTOOL_A_CABLE_RESULT_CODE_UNSPEC;
+	}
+
+	*finished = true;
+
+	ethnl_cable_test_result(phydev, ETHTOOL_A_CABLE_PAIR_A, stat);
+
+	return phy_init_hw(phydev);
+}
+
 static int dp83tg720_config_aneg(struct phy_device *phydev)
 {
 	int ret;
@@ -195,12 +346,15 @@ static struct phy_driver dp83tg720_driver[] = {
 	PHY_ID_MATCH_MODEL(DP83TG720S_PHY_ID),
 	.name		= "TI DP83TG720S",
 
+	.flags          = PHY_POLL_CABLE_TEST,
 	.config_aneg	= dp83tg720_config_aneg,
 	.read_status	= dp83tg720_read_status,
 	.get_features	= genphy_c45_pma_read_ext_abilities,
 	.config_init	= dp83tg720_config_init,
 	.get_sqi	= dp83tg720_get_sqi,
 	.get_sqi_max	= dp83tg720_get_sqi_max,
+	.cable_test_start = dp83tg720_cable_test_start,
+	.cable_test_get_status = dp83tg720_cable_test_get_status,
 
 	.suspend	= genphy_suspend,
 	.resume		= genphy_resume,
-- 
2.39.2

Re: [PATCH net-next v5 1/3] ethtool: Add new result codes for TDR diagnostics

[Jakub Kicinski]

On Mon, 12 Aug 2024 09:30:44 +0200 Oleksij Rempel wrote:
> Add new result codes to support TDR diagnostics in preparation for
> Open Alliance 1000BaseT1 TDR support:
> 
> - ETHTOOL_A_CABLE_RESULT_CODE_NOISE: TDR not possible due to high noise
>   level.
> - ETHTOOL_A_CABLE_RESULT_CODE_RESOLUTION_NOT_POSSIBLE: TDR resolution not
>   possible / out of distance.

Oleksij, please improve your postings. You have no cover letter here.
No link to previous postings. You didn't take Andrew's review tags 
from v4.

Re: [PATCH net-next v5 1/3] ethtool: Add new result codes for TDR diagnostics

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 12 Aug 2024 09:30:44 +0200 you wrote:
> Add new result codes to support TDR diagnostics in preparation for
> Open Alliance 1000BaseT1 TDR support:
> 
> - ETHTOOL_A_CABLE_RESULT_CODE_NOISE: TDR not possible due to high noise
>   level.
> - ETHTOOL_A_CABLE_RESULT_CODE_RESOLUTION_NOT_POSSIBLE: TDR resolution not
>   possible / out of distance.
> 
> [...]

Here is the summary with links:
  - [net-next,v5,1/3] ethtool: Add new result codes for TDR diagnostics
    https://git.kernel.org/netdev/net-next/c/2140e63cd87f
  - [net-next,v5,2/3] phy: Add Open Alliance helpers for the PHY framework
    https://git.kernel.org/netdev/net-next/c/9e7c1a9b9033
  - [net-next,v5,3/3] net: phy: dp83tg720: Add cable testing support
    https://git.kernel.org/netdev/net-next/c/20f77dc72471

You are awesome, thank you!
-- 
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