diff --git a/drivers/net/phy/bcm-phy-lib.c b/drivers/net/phy/bcm-phy-lib.c
index 41c728fbcfb2..4c4ee72a2e52 100644
--- a/drivers/net/phy/bcm-phy-lib.c
+++ b/drivers/net/phy/bcm-phy-lib.c
@@ -4,12 +4,14 @@
  */
 
 #include "bcm-phy-lib.h"
+#include <linux/bitfield.h>
 #include <linux/brcmphy.h>
 #include <linux/export.h>
 #include <linux/mdio.h>
 #include <linux/module.h>
 #include <linux/phy.h>
 #include <linux/ethtool.h>
+#include <linux/ethtool_netlink.h>
 
 #define MII_BCM_CHANNEL_WIDTH     0x2000
 #define BCM_CL45VEN_EEE_ADV       0x3c
@@ -581,6 +583,198 @@ int bcm_phy_enable_jumbo(struct phy_device *phydev)
 }
 EXPORT_SYMBOL_GPL(bcm_phy_enable_jumbo);
 
+int __bcm_phy_enable_rdb_access(struct phy_device *phydev)
+{
+	return __bcm_phy_write_exp(phydev, BCM54XX_EXP_REG7E, 0);
+}
+EXPORT_SYMBOL_GPL(__bcm_phy_enable_rdb_access);
+
+int __bcm_phy_enable_legacy_access(struct phy_device *phydev)
+{
+	return __bcm_phy_write_rdb(phydev, BCM54XX_RDB_REG0087,
+				   BCM54XX_ACCESS_MODE_LEGACY_EN);
+}
+EXPORT_SYMBOL_GPL(__bcm_phy_enable_legacy_access);
+
+static int _bcm_phy_cable_test_start(struct phy_device *phydev, bool is_rdb)
+{
+	u16 mask, set;
+	int ret;
+
+	/* Auto-negotiation must be enabled for cable diagnostics to work, but
+	 * don't advertise any capabilities.
+	 */
+	phy_write(phydev, MII_BMCR, BMCR_ANENABLE);
+	phy_write(phydev, MII_ADVERTISE, ADVERTISE_CSMA);
+	phy_write(phydev, MII_CTRL1000, 0);
+
+	phy_lock_mdio_bus(phydev);
+	if (is_rdb) {
+		ret = __bcm_phy_enable_legacy_access(phydev);
+		if (ret)
+			goto out;
+	}
+
+	mask = BCM54XX_ECD_CTRL_CROSS_SHORT_DIS | BCM54XX_ECD_CTRL_UNIT_MASK;
+	set = BCM54XX_ECD_CTRL_RUN | BCM54XX_ECD_CTRL_BREAK_LINK |
+	      FIELD_PREP(BCM54XX_ECD_CTRL_UNIT_MASK,
+			 BCM54XX_ECD_CTRL_UNIT_CM);
+
+	ret = __bcm_phy_modify_exp(phydev, BCM54XX_EXP_ECD_CTRL, mask, set);
+
+out:
+	/* re-enable the RDB access even if there was an error */
+	if (is_rdb)
+		ret = __bcm_phy_enable_rdb_access(phydev) ? : ret;
+
+	phy_unlock_mdio_bus(phydev);
+
+	return ret;
+}
+
+static int bcm_phy_cable_test_report_trans(int result)
+{
+	switch (result) {
+	case BCM54XX_ECD_FAULT_TYPE_OK:
+		return ETHTOOL_A_CABLE_RESULT_CODE_OK;
+	case BCM54XX_ECD_FAULT_TYPE_OPEN:
+		return ETHTOOL_A_CABLE_RESULT_CODE_OPEN;
+	case BCM54XX_ECD_FAULT_TYPE_SAME_SHORT:
+		return ETHTOOL_A_CABLE_RESULT_CODE_SAME_SHORT;
+	case BCM54XX_ECD_FAULT_TYPE_CROSS_SHORT:
+		return ETHTOOL_A_CABLE_RESULT_CODE_CROSS_SHORT;
+	case BCM54XX_ECD_FAULT_TYPE_INVALID:
+	case BCM54XX_ECD_FAULT_TYPE_BUSY:
+	default:
+		return ETHTOOL_A_CABLE_RESULT_CODE_UNSPEC;
+	}
+}
+
+static bool bcm_phy_distance_valid(int result)
+{
+	switch (result) {
+	case BCM54XX_ECD_FAULT_TYPE_OPEN:
+	case BCM54XX_ECD_FAULT_TYPE_SAME_SHORT:
+	case BCM54XX_ECD_FAULT_TYPE_CROSS_SHORT:
+		return true;
+	}
+	return false;
+}
+
+static int bcm_phy_report_length(struct phy_device *phydev, int result,
+				 int pair)
+{
+	int val;
+
+	val = __bcm_phy_read_exp(phydev,
+				 BCM54XX_EXP_ECD_PAIR_A_LENGTH_RESULTS + pair);
+	if (val < 0)
+		return val;
+
+	if (val == BCM54XX_ECD_LENGTH_RESULTS_INVALID)
+		return 0;
+
+	/* intra-pair shorts report twice the length */
+	if (result == BCM54XX_ECD_FAULT_TYPE_CROSS_SHORT)
+		val >>= 1;
+
+	ethnl_cable_test_fault_length(phydev, pair, val);
+
+	return 0;
+}
+
+static int _bcm_phy_cable_test_get_status(struct phy_device *phydev,
+					  bool *finished, bool is_rdb)
+{
+	int pair_a, pair_b, pair_c, pair_d, ret;
+
+	*finished = false;
+
+	phy_lock_mdio_bus(phydev);
+
+	if (is_rdb) {
+		ret = __bcm_phy_enable_legacy_access(phydev);
+		if (ret)
+			goto out;
+	}
+
+	ret = __bcm_phy_read_exp(phydev, BCM54XX_EXP_ECD_CTRL);
+	if (ret < 0)
+		goto out;
+
+	if (ret & BCM54XX_ECD_CTRL_IN_PROGRESS) {
+		ret = 0;
+		goto out;
+	}
+
+	ret = __bcm_phy_read_exp(phydev, BCM54XX_EXP_ECD_FAULT_TYPE);
+	if (ret < 0)
+		goto out;
+
+	pair_a = FIELD_GET(BCM54XX_ECD_FAULT_TYPE_PAIR_A_MASK, ret);
+	pair_b = FIELD_GET(BCM54XX_ECD_FAULT_TYPE_PAIR_B_MASK, ret);
+	pair_c = FIELD_GET(BCM54XX_ECD_FAULT_TYPE_PAIR_C_MASK, ret);
+	pair_d = FIELD_GET(BCM54XX_ECD_FAULT_TYPE_PAIR_D_MASK, ret);
+
+	ethnl_cable_test_result(phydev, ETHTOOL_A_CABLE_PAIR_A,
+				bcm_phy_cable_test_report_trans(pair_a));
+	ethnl_cable_test_result(phydev, ETHTOOL_A_CABLE_PAIR_B,
+				bcm_phy_cable_test_report_trans(pair_b));
+	ethnl_cable_test_result(phydev, ETHTOOL_A_CABLE_PAIR_C,
+				bcm_phy_cable_test_report_trans(pair_c));
+	ethnl_cable_test_result(phydev, ETHTOOL_A_CABLE_PAIR_D,
+				bcm_phy_cable_test_report_trans(pair_d));
+
+	if (bcm_phy_distance_valid(pair_a))
+		bcm_phy_report_length(phydev, pair_a, 0);
+	if (bcm_phy_distance_valid(pair_b))
+		bcm_phy_report_length(phydev, pair_b, 1);
+	if (bcm_phy_distance_valid(pair_c))
+		bcm_phy_report_length(phydev, pair_c, 2);
+	if (bcm_phy_distance_valid(pair_d))
+		bcm_phy_report_length(phydev, pair_d, 3);
+
+	ret = 0;
+	*finished = true;
+out:
+	/* re-enable the RDB access even if there was an error */
+	if (is_rdb)
+		ret = __bcm_phy_enable_rdb_access(phydev) ? : ret;
+
+	phy_unlock_mdio_bus(phydev);
+
+	return ret;
+}
+
+int bcm_phy_cable_test_start(struct phy_device *phydev)
+{
+	return _bcm_phy_cable_test_start(phydev, false);
+}
+EXPORT_SYMBOL_GPL(bcm_phy_cable_test_start);
+
+int bcm_phy_cable_test_get_status(struct phy_device *phydev, bool *finished)
+{
+	return _bcm_phy_cable_test_get_status(phydev, finished, false);
+}
+EXPORT_SYMBOL_GPL(bcm_phy_cable_test_get_status);
+
+/* We assume that all PHYs which support RDB access can be switched to legacy
+ * mode. If, in the future, this is not true anymore, we have to re-implement
+ * this with RDB access.
+ */
+int bcm_phy_cable_test_start_rdb(struct phy_device *phydev)
+{
+	return _bcm_phy_cable_test_start(phydev, true);
+}
+EXPORT_SYMBOL_GPL(bcm_phy_cable_test_start_rdb);
+
+int bcm_phy_cable_test_get_status_rdb(struct phy_device *phydev,
+				      bool *finished)
+{
+	return _bcm_phy_cable_test_get_status(phydev, finished, true);
+}
+EXPORT_SYMBOL_GPL(bcm_phy_cable_test_get_status_rdb);
+
 MODULE_DESCRIPTION("Broadcom PHY Library");
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Broadcom Corporation");
diff --git a/drivers/net/phy/bcm-phy-lib.h b/drivers/net/phy/bcm-phy-lib.h
index b35d880220b9..237a8503c9b4 100644
--- a/drivers/net/phy/bcm-phy-lib.h
+++ b/drivers/net/phy/bcm-phy-lib.h
@@ -80,4 +80,10 @@ void bcm_phy_r_rc_cal_reset(struct phy_device *phydev);
 int bcm_phy_28nm_a0b0_afe_config_init(struct phy_device *phydev);
 int bcm_phy_enable_jumbo(struct phy_device *phydev);
 
+int bcm_phy_cable_test_get_status_rdb(struct phy_device *phydev,
+				      bool *finished);
+int bcm_phy_cable_test_start_rdb(struct phy_device *phydev);
+int bcm_phy_cable_test_start(struct phy_device *phydev);
+int bcm_phy_cable_test_get_status(struct phy_device *phydev, bool *finished);
+
 #endif /* _LINUX_BCM_PHY_LIB_H */
diff --git a/include/linux/brcmphy.h b/include/linux/brcmphy.h
index 58d0150acc3e..d41624db6de2 100644
--- a/include/linux/brcmphy.h
+++ b/include/linux/brcmphy.h
@@ -119,6 +119,11 @@
 #define MII_BCM54XX_RDB_ADDR	0x1e
 #define MII_BCM54XX_RDB_DATA	0x1f
 
+/* legacy access control via rdb/expansion register */
+#define BCM54XX_RDB_REG0087		0x0087
+#define BCM54XX_EXP_REG7E		(MII_BCM54XX_EXP_SEL_ER + 0x7E)
+#define BCM54XX_ACCESS_MODE_LEGACY_EN	BIT(15)
+
 /*
  * AUXILIARY CONTROL SHADOW ACCESS REGISTERS.  (PHY REG 0x18)
  */
@@ -294,4 +299,51 @@
 #define MII_BRCM_CORE_EXPB0	0xB0
 #define MII_BRCM_CORE_EXPB1	0xB1
 
+/* Enhanced Cable Diagnostics */
+#define BCM54XX_RDB_ECD_CTRL			0x2a0
+#define BCM54XX_EXP_ECD_CTRL			(MII_BCM54XX_EXP_SEL_ER + 0xc0)
+
+#define BCM54XX_ECD_CTRL_CABLE_TYPE_CAT3	1	/* CAT3 or worse */
+#define BCM54XX_ECD_CTRL_CABLE_TYPE_CAT5	0	/* CAT5 or better */
+#define BCM54XX_ECD_CTRL_CABLE_TYPE_MASK	BIT(0)	/* cable type */
+#define BCM54XX_ECD_CTRL_INVALID		BIT(3)	/* invalid result */
+#define BCM54XX_ECD_CTRL_UNIT_CM		0	/* centimeters */
+#define BCM54XX_ECD_CTRL_UNIT_M			1	/* meters */
+#define BCM54XX_ECD_CTRL_UNIT_MASK		BIT(10)	/* cable length unit */
+#define BCM54XX_ECD_CTRL_IN_PROGRESS		BIT(11)	/* test in progress */
+#define BCM54XX_ECD_CTRL_BREAK_LINK		BIT(12)	/* unconnect link
+							 * during test
+							 */
+#define BCM54XX_ECD_CTRL_CROSS_SHORT_DIS	BIT(13)	/* disable inter-pair
+							 * short check
+							 */
+#define BCM54XX_ECD_CTRL_RUN			BIT(15)	/* run immediate */
+
+#define BCM54XX_RDB_ECD_FAULT_TYPE		0x2a1
+#define BCM54XX_EXP_ECD_FAULT_TYPE		(MII_BCM54XX_EXP_SEL_ER + 0xc1)
+#define BCM54XX_ECD_FAULT_TYPE_INVALID		0x0
+#define BCM54XX_ECD_FAULT_TYPE_OK		0x1
+#define BCM54XX_ECD_FAULT_TYPE_OPEN		0x2
+#define BCM54XX_ECD_FAULT_TYPE_SAME_SHORT	0x3 /* short same pair */
+#define BCM54XX_ECD_FAULT_TYPE_CROSS_SHORT	0x4 /* short different pairs */
+#define BCM54XX_ECD_FAULT_TYPE_BUSY		0x9
+#define BCM54XX_ECD_FAULT_TYPE_PAIR_D_MASK	GENMASK(3, 0)
+#define BCM54XX_ECD_FAULT_TYPE_PAIR_C_MASK	GENMASK(7, 4)
+#define BCM54XX_ECD_FAULT_TYPE_PAIR_B_MASK	GENMASK(11, 8)
+#define BCM54XX_ECD_FAULT_TYPE_PAIR_A_MASK	GENMASK(15, 12)
+#define BCM54XX_ECD_PAIR_A_LENGTH_RESULTS	0x2a2
+#define BCM54XX_ECD_PAIR_B_LENGTH_RESULTS	0x2a3
+#define BCM54XX_ECD_PAIR_C_LENGTH_RESULTS	0x2a4
+#define BCM54XX_ECD_PAIR_D_LENGTH_RESULTS	0x2a5
+
+#define BCM54XX_RDB_ECD_PAIR_A_LENGTH_RESULTS	0x2a2
+#define BCM54XX_EXP_ECD_PAIR_A_LENGTH_RESULTS	(MII_BCM54XX_EXP_SEL_ER + 0xc2)
+#define BCM54XX_RDB_ECD_PAIR_B_LENGTH_RESULTS	0x2a3
+#define BCM54XX_EXP_ECD_PAIR_B_LENGTH_RESULTS	(MII_BCM54XX_EXP_SEL_ER + 0xc3)
+#define BCM54XX_RDB_ECD_PAIR_C_LENGTH_RESULTS	0x2a4
+#define BCM54XX_EXP_ECD_PAIR_C_LENGTH_RESULTS	(MII_BCM54XX_EXP_SEL_ER + 0xc4)
+#define BCM54XX_RDB_ECD_PAIR_D_LENGTH_RESULTS	0x2a5
+#define BCM54XX_EXP_ECD_PAIR_D_LENGTH_RESULTS	(MII_BCM54XX_EXP_SEL_ER + 0xc5)
+#define BCM54XX_ECD_LENGTH_RESULTS_INVALID	0xffff
+
 #endif /* _LINUX_BRCMPHY_H */
