Merge branch 'master' of git://git.denx.de/u-boot-netWIP/18Jul2019

21 files changed, 770 insertions, 15 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index bc67c49965..2fcc60f40f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -616,6 +616,7 @@ M:	Joe Hershberger <joe.hershberger@ni.com>
 S:	Maintained
 T:	git https://gitlab.denx.de/u-boot/custodians/u-boot-net.git
 F:	drivers/net/
+F:	include/net.h
 F:	net/
 
 NIOS
diff --git a/arch/Kconfig b/arch/Kconfig
index a946af816f..949eb28dfa 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -125,6 +125,7 @@ config SANDBOX
 	imply PCH
 	imply PHYLIB
 	imply DM_MDIO
+	imply DM_MDIO_MUX
 
 config SH
 	bool "SuperH architecture"
diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index 531c1afc97..a0856764f6 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -824,7 +824,28 @@
 		dma-names = "m2m", "tx0", "rx0";
 	};
 
-	mdio-test {
+	/*
+	 * keep mdio-mux ahead of mdio so that the mux is removed first at the
+	 * end of the test.  If parent mdio is removed first, clean-up of the
+	 * mux will trigger a 2nd probe of parent-mdio, leaving parent-mdio
+	 * active at the end of the test.  That it turn doesn't allow the mdio
+	 * class to be destroyed, triggering an error.
+	 */
+	mdio-mux-test {
+		compatible = "sandbox,mdio-mux";
+		#address-cells = <1>;
+		#size-cells = <0>;
+		mdio-parent-bus = <&mdio>;
+
+		mdio-ch-test@0 {
+			reg = <0>;
+		};
+		mdio-ch-test@1 {
+			reg = <1>;
+		};
+	};
+
+	mdio: mdio-test {
 		compatible = "sandbox,mdio";
 	};
 };
diff --git a/cmd/mdio.c b/cmd/mdio.c
index a6fa9266d0..add6440813 100644
--- a/cmd/mdio.c
+++ b/cmd/mdio.c
@@ -268,6 +268,11 @@ static int do_mdio(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 		break;
 	}
 
+	if (!bus) {
+		puts("No MDIO bus found\n");
+		return CMD_RET_FAILURE;
+	}
+
 	if (op[0] == 'l') {
 		mdio_list_devices();
 
diff --git a/doc/device-tree-bindings/net/mdio-mux.txt b/doc/device-tree-bindings/net/mdio-mux.txt
new file mode 100644
index 0000000000..eaa31efda2
--- /dev/null
+++ b/doc/device-tree-bindings/net/mdio-mux.txt
@@ -0,0 +1,138 @@
+The expected structure of an MDIO MUX device tree node is described here.  This
+is heavily based on current Linux specification.
+One notable difference to Linux is that mdio-parent-bus is currently required
+by U-Boot, not optional as is in Linux.  Current U-Boot MDIO MUX udevice class
+implementation does not have specific support for MDIOs with an integrated MUX,
+the property should be made optional if such support is added.
+
+The MDIO buses downstream of the MUX should be described in the device tree as
+child nodes as indicated below.
+
+Required properties:
+mdio-parent-bus = a phandle to the MDIO bus used to perform actual I/O.  This is
+                  typically a real MDIO device, unless there are cascaded MUXes.
+#address-cells = <1>, each MDIO group is identified by one 32b value.
+#size-cells = <0>
+
+Other properties:
+The properties described here are sufficient for MDIO MUX DM class code, but
+MUX drivers may define additional properties, either required or optional.
+
+Required properties in child nodes:
+reg = value to be configured on the MUX to select the respective downstream
+      MDIO.
+
+Child nodes should normally contain PHY nodes, referenced by phandle from
+ethernet nodes of the eth interfaces using these PHYs.
+
+Example structure, extracted from Linux bindings document:
+
+	/* The parent MDIO bus. */
+	smi1: mdio@1180000001900 {
+		compatible = "cavium,octeon-3860-mdio";
+		#address-cells = <1>;
+		#size-cells = <0>;
+		reg = <0x11800 0x00001900 0x0 0x40>;
+	};
+	/*
+	 * An NXP sn74cbtlv3253 dual 1-of-4 switch controlled by a
+	 * pair of GPIO lines.  Child busses 2 and 3 populated with 4
+	 * PHYs each.
+	 */
+	mdio-mux {
+		compatible = "mdio-mux-gpio";
+		gpios = <&gpio1 3 0>, <&gpio1 4 0>;
+		mdio-parent-bus = <&smi1>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		mdio@2 {
+			reg = <2>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+			phy11: ethernet-phy@1 {
+				reg = <1>;
+				compatible = "marvell,88e1149r";
+				marvell,reg-init = <3 0x10 0 0x5777>,
+					<3 0x11 0 0x00aa>,
+					<3 0x12 0 0x4105>,
+					<3 0x13 0 0x0a60>;
+				interrupt-parent = <&gpio>;
+				interrupts = <10 8>; /* Pin 10, active low */
+			};
+			phy12: ethernet-phy@2 {
+				reg = <2>;
+				compatible = "marvell,88e1149r";
+				marvell,reg-init = <3 0x10 0 0x5777>,
+					<3 0x11 0 0x00aa>,
+					<3 0x12 0 0x4105>,
+					<3 0x13 0 0x0a60>;
+				interrupt-parent = <&gpio>;
+				interrupts = <10 8>; /* Pin 10, active low */
+			};
+			phy13: ethernet-phy@3 {
+				reg = <3>;
+				compatible = "marvell,88e1149r";
+				marvell,reg-init = <3 0x10 0 0x5777>,
+					<3 0x11 0 0x00aa>,
+					<3 0x12 0 0x4105>,
+					<3 0x13 0 0x0a60>;
+				interrupt-parent = <&gpio>;
+				interrupts = <10 8>; /* Pin 10, active low */
+			};
+			phy14: ethernet-phy@4 {
+				reg = <4>;
+				compatible = "marvell,88e1149r";
+				marvell,reg-init = <3 0x10 0 0x5777>,
+					<3 0x11 0 0x00aa>,
+					<3 0x12 0 0x4105>,
+					<3 0x13 0 0x0a60>;
+				interrupt-parent = <&gpio>;
+				interrupts = <10 8>; /* Pin 10, active low */
+			};
+		};
+		mdio@3 {
+			reg = <3>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+			phy21: ethernet-phy@1 {
+				reg = <1>;
+				compatible = "marvell,88e1149r";
+				marvell,reg-init = <3 0x10 0 0x5777>,
+					<3 0x11 0 0x00aa>,
+					<3 0x12 0 0x4105>,
+					<3 0x13 0 0x0a60>;
+				interrupt-parent = <&gpio>;
+				interrupts = <12 8>; /* Pin 12, active low */
+			};
+			phy22: ethernet-phy@2 {
+				reg = <2>;
+				compatible = "marvell,88e1149r";
+				marvell,reg-init = <3 0x10 0 0x5777>,
+					<3 0x11 0 0x00aa>,
+					<3 0x12 0 0x4105>,
+					<3 0x13 0 0x0a60>;
+				interrupt-parent = <&gpio>;
+				interrupts = <12 8>; /* Pin 12, active low */
+			};
+			phy23: ethernet-phy@3 {
+				reg = <3>;
+				compatible = "marvell,88e1149r";
+				marvell,reg-init = <3 0x10 0 0x5777>,
+					<3 0x11 0 0x00aa>,
+					<3 0x12 0 0x4105>,
+					<3 0x13 0 0x0a60>;
+				interrupt-parent = <&gpio>;
+				interrupts = <12 8>; /* Pin 12, active low */
+			};
+			phy24: ethernet-phy@4 {
+				reg = <4>;
+				compatible = "marvell,88e1149r";
+				marvell,reg-init = <3 0x10 0 0x5777>,
+					<3 0x11 0 0x00aa>,
+					<3 0x12 0 0x4105>,
+					<3 0x13 0 0x0a60>;
+				interrupt-parent = <&gpio>;
+				interrupts = <12 8>; /* Pin 12, active low */
+			};
+		};
+	};
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 635f8d72c2..403df5e960 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -24,6 +24,18 @@ config DM_MDIO
 	  This is currently implemented in net/mdio-uclass.c
 	  Look in include/miiphy.h for details.
 
+config DM_MDIO_MUX
+	bool "Enable Driver Model for MDIO MUX devices"
+	depends on DM_MDIO
+	help
+	  Enable driver model for MDIO MUX devices
+
+	  Adds UCLASS_MDIO_MUX DM class supporting MDIO MUXes.  Useful for
+	  systems that support DM_MDIO and integrate one or multiple muxes on
+	  the MDIO bus.
+	  This is currently implemented in net/mdio-mux-uclass.c
+	  Look in include/miiphy.h for details.
+
 config MDIO_SANDBOX
 	depends on DM_MDIO && SANDBOX
 	default y
@@ -34,6 +46,16 @@ config MDIO_SANDBOX
 
 	  This driver is used in for testing in test/dm/mdio.c
 
+config MDIO_MUX_SANDBOX
+	depends on DM_MDIO_MUX && MDIO_SANDBOX
+	default y
+	bool "Sandbox: Mocked MDIO-MUX driver"
+	help
+	  This driver implements dummy select/deselect ops mimicking a MUX on
+	  the MDIO bux.  It uses mdio_sandbox driver as parent MDIO.
+
+	  This driver is used for testing in test/dm/mdio.c
+
 menuconfig NETDEVICES
 	bool "Network device support"
 	depends on NET
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 40038427db..3c473b205d 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_LAN91C96) += lan91c96.o
 obj-$(CONFIG_LPC32XX_ETH) += lpc32xx_eth.o
 obj-$(CONFIG_MACB) += macb.o
 obj-$(CONFIG_MCFFEC) += mcffec.o mcfmii.o
+obj-$(CONFIG_MDIO_MUX_SANDBOX) += mdio_mux_sandbox.o
 obj-$(CONFIG_MPC8XX_FEC) += mpc8xx_fec.o
 obj-$(CONFIG_MT7628_ETH) += mt7628-eth.o
 obj-$(CONFIG_MVGBE) += mvgbe.o
diff --git a/drivers/net/designware.c b/drivers/net/designware.c
index 2c5d9560c5..3b6cf5ddb5 100644
--- a/drivers/net/designware.c
+++ b/drivers/net/designware.c
@@ -677,10 +677,10 @@ int designware_eth_probe(struct udevice *dev)
 	struct dw_eth_dev *priv = dev_get_priv(dev);
 	u32 iobase = pdata->iobase;
 	ulong ioaddr;
-	int ret;
+	int ret, err;
 	struct reset_ctl_bulk reset_bulk;
 #ifdef CONFIG_CLK
-	int i, err, clock_nb;
+	int i, clock_nb;
 
 	priv->clock_count = 0;
 	clock_nb = dev_count_phandle_with_args(dev, "clocks", "#clock-cells");
@@ -753,13 +753,23 @@ int designware_eth_probe(struct udevice *dev)
 	priv->interface = pdata->phy_interface;
 	priv->max_speed = pdata->max_speed;
 
-	dw_mdio_init(dev->name, dev);
+	ret = dw_mdio_init(dev->name, dev);
+	if (ret) {
+		err = ret;
+		goto mdio_err;
+	}
 	priv->bus = miiphy_get_dev_by_name(dev->name);
 
 	ret = dw_phy_init(priv, dev);
 	debug("%s, ret=%d\n", __func__, ret);
+	if (!ret)
+		return 0;
 
-	return ret;
+	/* continue here for cleanup if no PHY found */
+	err = ret;
+	mdio_unregister(priv->bus);
+	mdio_free(priv->bus);
+mdio_err:
 
 #ifdef CONFIG_CLK
 clk_err:
@@ -767,8 +777,8 @@ clk_err:
 	if (ret)
 		pr_err("failed to disable all clocks\n");
 
-	return err;
 #endif
+	return err;
 }
 
 static int designware_eth_remove(struct udevice *dev)
diff --git a/drivers/net/mdio_mux_sandbox.c b/drivers/net/mdio_mux_sandbox.c
new file mode 100644
index 0000000000..3dba4d18a1
--- /dev/null
+++ b/drivers/net/mdio_mux_sandbox.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2019
+ * Alex Marginean, NXP
+ */
+
+#include <dm.h>
+#include <errno.h>
+#include <miiphy.h>
+
+/* macros copied over from mdio_sandbox.c */
+#define SANDBOX_PHY_ADDR	5
+#define SANDBOX_PHY_REG_CNT	2
+
+struct mdio_mux_sandbox_priv {
+	int enabled;
+	int sel;
+};
+
+static int mdio_mux_sandbox_mark_selection(struct udevice *dev, int sel)
+{
+	struct udevice *mdio;
+	struct mdio_ops *ops;
+	int err;
+
+	/*
+	 * find the sandbox parent mdio and write a register on the PHY there
+	 * so the mux test can verify selection.
+	 */
+	err = uclass_get_device_by_name(UCLASS_MDIO, "mdio-test", &mdio);
+	if (err)
+		return err;
+	ops = mdio_get_ops(mdio);
+	return ops->write(mdio, SANDBOX_PHY_ADDR, MDIO_DEVAD_NONE,
+			  SANDBOX_PHY_REG_CNT - 1, (u16)sel);
+}
+
+static int mdio_mux_sandbox_select(struct udevice *dev, int cur, int sel)
+{
+	struct mdio_mux_sandbox_priv *priv = dev_get_priv(dev);
+
+	if (!priv->enabled)
+		return -ENODEV;
+
+	if (cur != priv->sel)
+		return -EINVAL;
+
+	priv->sel = sel;
+	mdio_mux_sandbox_mark_selection(dev, priv->sel);
+
+	return 0;
+}
+
+static int mdio_mux_sandbox_deselect(struct udevice *dev, int sel)
+{
+	struct mdio_mux_sandbox_priv *priv = dev_get_priv(dev);
+
+	if (!priv->enabled)
+		return -ENODEV;
+
+	if (sel != priv->sel)
+		return -EINVAL;
+
+	priv->sel = -1;
+	mdio_mux_sandbox_mark_selection(dev, priv->sel);
+
+	return 0;
+}
+
+static const struct mdio_mux_ops mdio_mux_sandbox_ops = {
+	.select = mdio_mux_sandbox_select,
+	.deselect = mdio_mux_sandbox_deselect,
+};
+
+static int mdio_mux_sandbox_probe(struct udevice *dev)
+{
+	struct mdio_mux_sandbox_priv *priv = dev_get_priv(dev);
+
+	priv->enabled = 1;
+	priv->sel = -1;
+
+	return 0;
+}
+
+static const struct udevice_id mdio_mux_sandbox_ids[] = {
+	{ .compatible = "sandbox,mdio-mux" },
+	{ }
+};
+
+U_BOOT_DRIVER(mdio_mux_sandbox) = {
+	.name		= "mdio_mux_sandbox",
+	.id		= UCLASS_MDIO_MUX,
+	.of_match	= mdio_mux_sandbox_ids,
+	.probe		= mdio_mux_sandbox_probe,
+	.ops		= &mdio_mux_sandbox_ops,
+	.priv_auto_alloc_size = sizeof(struct mdio_mux_sandbox_priv),
+};
diff --git a/drivers/net/mdio_sandbox.c b/drivers/net/mdio_sandbox.c
index 07515e078c..df053f5381 100644
--- a/drivers/net/mdio_sandbox.c
+++ b/drivers/net/mdio_sandbox.c
@@ -9,11 +9,11 @@
 #include <miiphy.h>
 
 #define SANDBOX_PHY_ADDR	5
-#define SANDBOX_PHY_REG		0
+#define SANDBOX_PHY_REG_CNT	2
 
 struct mdio_sandbox_priv {
 	int enabled;
-	u16 reg;
+	u16 reg[SANDBOX_PHY_REG_CNT];
 };
 
 static int mdio_sandbox_read(struct udevice *dev, int addr, int devad, int reg)
@@ -27,10 +27,10 @@ static int mdio_sandbox_read(struct udevice *dev, int addr, int devad, int reg)
 		return -ENODEV;
 	if (devad != MDIO_DEVAD_NONE)
 		return -ENODEV;
-	if (reg != SANDBOX_PHY_REG)
+	if (reg < 0 || reg > SANDBOX_PHY_REG_CNT)
 		return -ENODEV;
 
-	return priv->reg;
+	return priv->reg[reg];
 }
 
 static int mdio_sandbox_write(struct udevice *dev, int addr, int devad, int reg,
@@ -45,10 +45,10 @@ static int mdio_sandbox_write(struct udevice *dev, int addr, int devad, int reg,
 		return -ENODEV;
 	if (devad != MDIO_DEVAD_NONE)
 		return -ENODEV;
-	if (reg != SANDBOX_PHY_REG)
+	if (reg < 0 || reg > SANDBOX_PHY_REG_CNT)
 		return -ENODEV;
 
-	priv->reg = val;
+	priv->reg[reg] = val;
 
 	return 0;
 }
@@ -56,8 +56,10 @@ static int mdio_sandbox_write(struct udevice *dev, int addr, int devad, int reg,
 static int mdio_sandbox_reset(struct udevice *dev)
 {
 	struct mdio_sandbox_priv *priv = dev_get_priv(dev);
+	int i;
 
-	priv->reg = 0;
+	for (i = 0; i < SANDBOX_PHY_REG_CNT; i++)
+		priv->reg[i] = 0;
 
 	return 0;
 }
diff --git a/drivers/net/phy/aquantia.c b/drivers/net/phy/aquantia.c
index 5c3298d612..465ec2d342 100644
--- a/drivers/net/phy/aquantia.c
+++ b/drivers/net/phy/aquantia.c
@@ -461,6 +461,19 @@ struct phy_driver aqr107_driver = {
 	.shutdown = &gen10g_shutdown,
 };
 
+struct phy_driver aqr112_driver = {
+	.name = "Aquantia AQR112",
+	.uid = 0x3a1b660,
+	.mask = 0xfffffff0,
+	.features = PHY_10G_FEATURES,
+	.mmds = (MDIO_MMD_PMAPMD | MDIO_MMD_PCS |
+		 MDIO_MMD_PHYXS | MDIO_MMD_AN |
+		 MDIO_MMD_VEND1),
+	.config = &aquantia_config,
+	.startup = &aquantia_startup,
+	.shutdown = &gen10g_shutdown,
+};
+
 struct phy_driver aqr405_driver = {
 	.name = "Aquantia AQR405",
 	.uid = 0x3a1b4b2,
@@ -474,6 +487,19 @@ struct phy_driver aqr405_driver = {
 	.shutdown = &gen10g_shutdown,
 };
 
+struct phy_driver aqr412_driver = {
+	.name = "Aquantia AQR412",
+	.uid = 0x3a1b710,
+	.mask = 0xfffffff0,
+	.features = PHY_10G_FEATURES,
+	.mmds = (MDIO_MMD_PMAPMD | MDIO_MMD_PCS |
+		 MDIO_MMD_PHYXS | MDIO_MMD_AN |
+		 MDIO_MMD_VEND1),
+	.config = &aquantia_config,
+	.startup = &aquantia_startup,
+	.shutdown = &gen10g_shutdown,
+};
+
 int phy_aquantia_init(void)
 {
 	phy_register(&aq1202_driver);
@@ -481,7 +507,9 @@ int phy_aquantia_init(void)
 	phy_register(&aqr105_driver);
 	phy_register(&aqr106_driver);
 	phy_register(&aqr107_driver);
+	phy_register(&aqr112_driver);
 	phy_register(&aqr405_driver);
+	phy_register(&aqr412_driver);
 
 	return 0;
 }
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index c1c1af9abd..ae37dd6c1e 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -727,12 +727,23 @@ static struct phy_device *create_phy_by_mask(struct mii_dev *bus,
 	while (phy_mask) {
 		int addr = ffs(phy_mask) - 1;
 		int r = get_phy_id(bus, addr, devad, &phy_id);
+
+		/*
+		 * If the PHY ID is flat 0 we ignore it.  There are C45 PHYs
+		 * that return all 0s for C22 reads (like Aquantia AQR112) and
+		 * there are C22 PHYs that return all 0s for C45 reads (like
+		 * Atheros AR8035).
+		 */
+		if (r == 0 && phy_id == 0)
+			goto next;
+
 		/* If the PHY ID is mostly f's, we didn't find anything */
 		if (r == 0 && (phy_id & 0x1fffffff) != 0x1fffffff) {
 			is_c45 = (devad == MDIO_DEVAD_NONE) ? false : true;
 			return phy_device_create(bus, addr, phy_id, is_c45,
 						 interface);
 		}
+next:
 		phy_mask &= ~(1 << addr);
 	}
 	return NULL;
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index f9300a64ce..d4d96106b3 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -59,6 +59,7 @@ enum uclass_id {
 	UCLASS_MAILBOX,		/* Mailbox controller */
 	UCLASS_MASS_STORAGE,	/* Mass storage device */
 	UCLASS_MDIO,		/* MDIO bus */
+	UCLASS_MDIO_MUX,	/* MDIO MUX/switch */
 	UCLASS_MISC,		/* Miscellaneous device */
 	UCLASS_MMC,		/* SD / MMC card or chip */
 	UCLASS_MOD_EXP,		/* RSA Mod Exp device */
diff --git a/include/miiphy.h b/include/miiphy.h
index e6dd441983..9b97d09f18 100644
--- a/include/miiphy.h
+++ b/include/miiphy.h
@@ -167,4 +167,24 @@ struct phy_device *dm_mdio_phy_connect(struct udevice *dev, int addr,
 
 #endif
 
+#ifdef CONFIG_DM_MDIO_MUX
+
+/* indicates none of the child buses is selected */
+#define MDIO_MUX_SELECT_NONE	-1
+
+/**
+ * struct mdio_mux_ops - MDIO MUX operations
+ *
+ * @select: Selects a child bus
+ * @deselect: Clean up selection.  Optional, can be NULL
+ */
+struct mdio_mux_ops {
+	int (*select)(struct udevice *mux, int cur, int sel);
+	int (*deselect)(struct udevice *mux, int sel);
+};
+
+#define mdio_mux_get_ops(dev) ((struct mdio_mux_ops *)(dev)->driver->ops)
+
+#endif
+
 #endif
diff --git a/include/net.h b/include/net.h
index 44b32385c4..7684076af6 100644
--- a/include/net.h
+++ b/include/net.h
@@ -728,7 +728,7 @@ static inline struct in_addr net_read_ip(void *from)
 }
 
 /* return ulong *in network byteorder* */
-static inline u32 net_read_u32(u32 *from)
+static inline u32 net_read_u32(void *from)
 {
 	u32 l;
 
@@ -749,7 +749,7 @@ static inline void net_copy_ip(void *to, void *from)
 }
 
 /* copy ulong */
-static inline void net_copy_u32(u32 *to, u32 *from)
+static inline void net_copy_u32(void *to, void *from)
 {
 	memcpy((void *)to, (void *)from, sizeof(u32));
 }
diff --git a/include/phy.h b/include/phy.h
index d01435d1aa..f4530faeb9 100644
--- a/include/phy.h
+++ b/include/phy.h
@@ -246,15 +246,71 @@ static inline int is_10g_interface(phy_interface_t interface)
 
 #endif
 
+/**
+ * phy_init() - Initializes the PHY drivers
+ *
+ * This function registers all available PHY drivers
+ *
+ * @return 0 if OK, -ve on error
+ */
 int phy_init(void);
+
+/**
+ * phy_reset() - Resets the specified PHY
+ *
+ * Issues a reset of the PHY and waits for it to complete
+ *
+ * @phydev:	PHY to reset
+ * @return 0 if OK, -ve on error
+ */
 int phy_reset(struct phy_device *phydev);
+
+/**
+ * phy_find_by_mask() - Searches for a PHY on the specified MDIO bus
+ *
+ * The function checks the PHY addresses flagged in phy_mask and returns a
+ * phy_device pointer if it detects a PHY.
+ * This function should only be called if just one PHY is expected to be present
+ * in the set of addresses flagged in phy_mask.  If multiple PHYs are present,
+ * it is undefined which of these PHYs is returned.
+ *
+ * @bus:	MII/MDIO bus to scan
+ * @phy_mask:	bitmap of PYH addresses to scan
+ * @interface:	type of MAC-PHY interface
+ * @return pointer to phy_device if a PHY is found, or NULL otherwise
+ */
 struct phy_device *phy_find_by_mask(struct mii_dev *bus, unsigned phy_mask,
 		phy_interface_t interface);
+
 #ifdef CONFIG_DM_ETH
+
+/**
+ * phy_connect_dev() - Associates the given pair of PHY and Ethernet devices
+ * @phydev:	PHY device
+ * @dev:	Ethernet device
+ */
 void phy_connect_dev(struct phy_device *phydev, struct udevice *dev);
+
+/**
+ * phy_connect() - Creates a PHY device for the Ethernet interface
+ *
+ * Creates a PHY device for the PHY at the given address, if one doesn't exist
+ * already, and associates it with the Ethernet device.
+ * The function may be called with addr <= 0, in this case addr value is ignored
+ * and the bus is scanned to detect a PHY.  Scanning should only be used if only
+ * one PHY is expected to be present on the MDIO bus, otherwise it is undefined
+ * which PHY is returned.
+ *
+ * @bus:	MII/MDIO bus that hosts the PHY
+ * @addr:	PHY address on MDIO bus
+ * @dev:	Ethernet device to associate to the PHY
+ * @interface:	type of MAC-PHY interface
+ * @return pointer to phy_device if a PHY is found, or NULL otherwise
+ */
 struct phy_device *phy_connect(struct mii_dev *bus, int addr,
 				struct udevice *dev,
 				phy_interface_t interface);
+
 static inline ofnode phy_get_ofnode(struct phy_device *phydev)
 {
 	if (ofnode_valid(phydev->node))
@@ -263,10 +319,34 @@ static inline ofnode phy_get_ofnode(struct phy_device *phydev)
 		return dev_ofnode(phydev->dev);
 }
 #else
+
+/**
+ * phy_connect_dev() - Associates the given pair of PHY and Ethernet devices
+ * @phydev:	PHY device
+ * @dev:	Ethernet device
+ */
 void phy_connect_dev(struct phy_device *phydev, struct eth_device *dev);
+
+/**
+ * phy_connect() - Creates a PHY device for the Ethernet interface
+ *
+ * Creates a PHY device for the PHY at the given address, if one doesn't exist
+ * already, and associates it with the Ethernet device.
+ * The function may be called with addr <= 0, in this case addr value is ignored
+ * and the bus is scanned to detect a PHY.  Scanning should only be used if only
+ * one PHY is expected to be present on the MDIO bus, otherwise it is undefined
+ * which PHY is returned.
+ *
+ * @bus:	MII/MDIO bus that hosts the PHY
+ * @addr:	PHY address on MDIO bus
+ * @dev:	Ethernet device to associate to the PHY
+ * @interface:	type of MAC-PHY interface
+ * @return pointer to phy_device if a PHY is found, or NULL otherwise
+ */
 struct phy_device *phy_connect(struct mii_dev *bus, int addr,
 				struct eth_device *dev,
 				phy_interface_t interface);
+
 static inline ofnode phy_get_ofnode(struct phy_device *phydev)
 {
 	return ofnode_null();
diff --git a/net/Makefile b/net/Makefile
index 6251ff3991..826544f05f 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -16,6 +16,7 @@ else
 obj-$(CONFIG_NET)      += eth_legacy.o
 endif
 obj-$(CONFIG_DM_MDIO)  += mdio-uclass.o
+obj-$(CONFIG_DM_MDIO_MUX) += mdio-mux-uclass.o
 obj-$(CONFIG_NET)      += eth_common.o
 obj-$(CONFIG_CMD_LINK_LOCAL) += link_local.o
 obj-$(CONFIG_NET)      += net.o
diff --git a/net/mdio-mux-uclass.c b/net/mdio-mux-uclass.c
new file mode 100644
index 0000000000..e425207d6e
--- /dev/null
+++ b/net/mdio-mux-uclass.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2019
+ * Alex Marginean, NXP
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <miiphy.h>
+#include <dm/device-internal.h>
+#include <dm/uclass-internal.h>
+#include <dm/lists.h>
+
+#define MDIO_MUX_CHILD_DRV_NAME	"mdio-mux-bus-drv"
+
+/**
+ * struct mdio_mux_perdev_priv - Per-device class data for MDIO MUX DM
+ *
+ * @parent_mdio: Parent DM MDIO device, this is called for actual MDIO I/O after
+ *               setting up the mux.  Typically this is a real MDIO device,
+ *               unless there are cascaded muxes.
+ * @selected:    Current child bus selection.  Defaults to -1
+ */
+struct mdio_mux_perdev_priv {
+	struct udevice *mdio_parent;
+	int selected;
+};
+
+/*
+ * This source file uses three types of devices, as follows:
+ * - mux is the hardware MDIO MUX which selects between the existing child MDIO
+ * buses, this is the device relevant for MDIO MUX class of drivers.
+ * - ch is a child MDIO bus, this is just a representation of a mux selection,
+ * not a real piece of hardware.
+ * - mdio_parent is the actual MDIO bus called to perform reads/writes after
+ * the MUX is configured.  Typically this is a real MDIO device, unless there
+ * are cascaded muxes.
+ */
+
+/**
+ * struct mdio_mux_ch_data - Per-device data for child MDIOs
+ *
+ * @sel: Selection value used by the MDIO MUX to access this child MDIO bus
+ */
+struct mdio_mux_ch_data {
+	int sel;
+};
+
+static struct udevice *mmux_get_parent_mdio(struct udevice *mux)
+{
+	struct mdio_mux_perdev_priv *pdata = dev_get_uclass_priv(mux);
+
+	return pdata->mdio_parent;
+}
+
+static struct mdio_ops *mmux_get_mdio_parent_ops(struct udevice *mux)
+{
+	return mdio_get_ops(mmux_get_parent_mdio(mux));
+}
+
+/* call driver select function before performing MDIO r/w */
+static int mmux_change_sel(struct udevice *ch, bool sel)
+{
+	struct udevice *mux = ch->parent;
+	struct mdio_mux_perdev_priv *priv = dev_get_uclass_priv(mux);
+	struct mdio_mux_ops *ops = mdio_mux_get_ops(mux);
+	struct mdio_mux_ch_data *ch_data = dev_get_parent_platdata(ch);
+	int err = 0;
+
+	if (sel) {
+		err = ops->select(mux, priv->selected, ch_data->sel);
+		if (err)
+			return err;
+
+		priv->selected = ch_data->sel;
+	} else {
+		if (ops->deselect) {
+			ops->deselect(mux, ch_data->sel);
+			priv->selected = MDIO_MUX_SELECT_NONE;
+		}
+	}
+
+	return 0;
+}
+
+/* Read wrapper, sets up the mux before issuing a read on parent MDIO bus */
+static int mmux_read(struct udevice *ch, int addr, int devad,
+		     int reg)
+{
+	struct udevice *mux = ch->parent;
+	struct udevice *parent_mdio = mmux_get_parent_mdio(mux);
+	struct mdio_ops *parent_ops = mmux_get_mdio_parent_ops(mux);
+	int err;
+
+	err = mmux_change_sel(ch, true);
+	if (err)
+		return err;
+
+	err = parent_ops->read(parent_mdio, addr, devad, reg);
+	mmux_change_sel(ch, false);
+
+	return err;
+}
+
+/* Write wrapper, sets up the mux before issuing a write on parent MDIO bus */
+static int mmux_write(struct udevice *ch, int addr, int devad,
+		      int reg, u16 val)
+{
+	struct udevice *mux = ch->parent;
+	struct udevice *parent_mdio = mmux_get_parent_mdio(mux);
+	struct mdio_ops *parent_ops = mmux_get_mdio_parent_ops(mux);
+	int err;
+
+	err = mmux_change_sel(ch, true);
+	if (err)
+		return err;
+
+	err = parent_ops->write(parent_mdio, addr, devad, reg, val);
+	mmux_change_sel(ch, false);
+
+	return err;
+}
+
+/* Reset wrapper, sets up the mux before issuing a reset on parent MDIO bus */
+static int mmux_reset(struct udevice *ch)
+{
+	struct udevice *mux = ch->parent;
+	struct udevice *parent_mdio = mmux_get_parent_mdio(mux);
+	struct mdio_ops *parent_ops = mmux_get_mdio_parent_ops(mux);
+	int err;
+
+	/* reset is optional, if it's not implemented just exit */
+	if (!parent_ops->reset)
+		return 0;
+
+	err = mmux_change_sel(ch, true);
+	if (err)
+		return err;
+
+	err = parent_ops->reset(parent_mdio);
+	mmux_change_sel(ch, false);
+
+	return err;
+}
+
+/* Picks up the mux selection value for each child */
+static int dm_mdio_mux_child_post_bind(struct udevice *ch)
+{
+	struct mdio_mux_ch_data *ch_data = dev_get_parent_platdata(ch);
+
+	ch_data->sel = dev_read_u32_default(ch, "reg", MDIO_MUX_SELECT_NONE);
+
+	if (ch_data->sel == MDIO_MUX_SELECT_NONE)
+		return -EINVAL;
+
+	return 0;
+}
+
+/* Explicitly bind child MDIOs after binding the mux */
+static int dm_mdio_mux_post_bind(struct udevice *mux)
+{
+	ofnode ch_node;
+	int err, first_err = 0;
+
+	if (!ofnode_valid(mux->node)) {
+		debug("%s: no mux node found, no child MDIO busses set up\n",
+		      __func__);
+		return 0;
+	}
+
+	/*
+	 * we're going by Linux bindings so the child nodes do not have
+	 * compatible strings.  We're going through them here and binding to
+	 * them.
+	 */
+	dev_for_each_subnode(ch_node, mux) {
+		struct udevice *ch_dev;
+		const char *ch_name;
+
+		ch_name = ofnode_get_name(ch_node);
+
+		err = device_bind_driver_to_node(mux, MDIO_MUX_CHILD_DRV_NAME,
+						 ch_name, ch_node, &ch_dev);
+		/* try to bind all, but keep 1st error */
+		if (err && !first_err)
+			first_err = err;
+	}
+
+	return first_err;
+}
+
+/* Get a reference to the parent MDIO bus, it should be bound by now */
+static int dm_mdio_mux_post_probe(struct udevice *mux)
+{
+	struct mdio_mux_perdev_priv *priv = dev_get_uclass_priv(mux);
+	int err;
+
+	priv->selected = MDIO_MUX_SELECT_NONE;
+
+	/* pick up mdio parent from device tree */
+	err = uclass_get_device_by_phandle(UCLASS_MDIO, mux, "mdio-parent-bus",
+					   &priv->mdio_parent);
+	if (err) {
+		debug("%s: didn't find mdio-parent-bus\n", __func__);
+		return err;
+	}
+
+	return 0;
+}
+
+const struct mdio_ops mmux_child_mdio_ops = {
+	.read = mmux_read,
+	.write = mmux_write,
+	.reset = mmux_reset,
+};
+
+/* MDIO class driver used for MUX child MDIO buses */
+U_BOOT_DRIVER(mdio_mux_child) = {
+	.name		= MDIO_MUX_CHILD_DRV_NAME,
+	.id		= UCLASS_MDIO,
+	.ops		= &mmux_child_mdio_ops,
+};
+
+UCLASS_DRIVER(mdio_mux) = {
+	.id = UCLASS_MDIO_MUX,
+	.name = "mdio-mux",
+	.child_post_bind = dm_mdio_mux_child_post_bind,
+	.post_bind  = dm_mdio_mux_post_bind,
+	.post_probe = dm_mdio_mux_post_probe,
+	.per_device_auto_alloc_size = sizeof(struct mdio_mux_perdev_priv),
+	.per_child_platdata_auto_alloc_size = sizeof(struct mdio_mux_ch_data),
+};
diff --git a/test/dm/Makefile b/test/dm/Makefile
index 6a36cc0a32..7b4dd6e12e 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -63,4 +63,5 @@ obj-$(CONFIG_TEE) += tee.o
 obj-$(CONFIG_VIRTIO_SANDBOX) += virtio.o
 obj-$(CONFIG_DMA) += dma.o
 obj-$(CONFIG_DM_MDIO) += mdio.o
+obj-$(CONFIG_DM_MDIO_MUX) += mdio_mux.o
 endif
diff --git a/test/dm/mdio.c b/test/dm/mdio.c
index 5b66255f7d..dc229aed6d 100644
--- a/test/dm/mdio.c
+++ b/test/dm/mdio.c
@@ -13,6 +13,9 @@
 
 /* macros copied over from mdio_sandbox.c */
 #define SANDBOX_PHY_ADDR	5
+#define SANDBOX_PHY_REG_CNT	2
+
+/* test using 1st register, 0 */
 #define SANDBOX_PHY_REG		0
 
 #define TEST_REG_VALUE		0xabcd
diff --git a/test/dm/mdio_mux.c b/test/dm/mdio_mux.c
new file mode 100644
index 0000000000..f962e09dbc
--- /dev/null
+++ b/test/dm/mdio_mux.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2019
+ * Alex Marginean, NXP
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/test.h>
+#include <misc.h>
+#include <test/ut.h>
+#include <miiphy.h>
+
+/* macros copied over from mdio_sandbox.c */
+#define SANDBOX_PHY_ADDR	5
+#define SANDBOX_PHY_REG_CNT	2
+
+#define TEST_REG_VALUE		0xabcd
+
+static int dm_test_mdio_mux(struct unit_test_state *uts)
+{
+	struct uclass *uc;
+	struct udevice *mux;
+	struct udevice *mdio_ch0, *mdio_ch1, *mdio;
+	struct mdio_ops *ops, *ops_parent;
+	struct mdio_mux_ops *mmops;
+	u16 reg;
+
+	ut_assertok(uclass_get(UCLASS_MDIO_MUX, &uc));
+
+	ut_assertok(uclass_get_device_by_name(UCLASS_MDIO_MUX, "mdio-mux-test",
+					      &mux));
+
+	ut_assertok(uclass_get_device_by_name(UCLASS_MDIO, "mdio-ch-test@0",
+					      &mdio_ch0));
+	ut_assertok(uclass_get_device_by_name(UCLASS_MDIO, "mdio-ch-test@1",
+					      &mdio_ch1));
+
+	ut_assertok(uclass_get_device_by_name(UCLASS_MDIO, "mdio-test", &mdio));
+
+	ops = mdio_get_ops(mdio_ch0);
+	ut_assertnonnull(ops);
+	ut_assertnonnull(ops->read);
+	ut_assertnonnull(ops->write);
+
+	mmops = mdio_mux_get_ops(mux);
+	ut_assertnonnull(mmops);
+	ut_assertnonnull(mmops->select);
+
+	ops_parent = mdio_get_ops(mdio);
+	ut_assertnonnull(ops);
+	ut_assertnonnull(ops->read);
+
+	/*
+	 * mux driver sets last register on the emulated PHY whenever a group
+	 * is selected to the selection #.  Just reading that register from
+	 * either of the child buses should return the id of the child bus
+	 */
+	reg = ops->read(mdio_ch0, SANDBOX_PHY_ADDR, MDIO_DEVAD_NONE,
+			SANDBOX_PHY_REG_CNT - 1);
+	ut_asserteq(reg, 0);
+
+	reg = ops->read(mdio_ch1, SANDBOX_PHY_ADDR, MDIO_DEVAD_NONE,
+			SANDBOX_PHY_REG_CNT - 1);
+	ut_asserteq(reg, 1);
+
+	mmops->select(mux, MDIO_MUX_SELECT_NONE, 5);
+	reg = ops_parent->read(mdio, SANDBOX_PHY_ADDR, MDIO_DEVAD_NONE,
+			SANDBOX_PHY_REG_CNT - 1);
+	ut_asserteq(reg, 5);
+
+	mmops->deselect(mux, 5);
+	reg = ops_parent->read(mdio, SANDBOX_PHY_ADDR, MDIO_DEVAD_NONE,
+			SANDBOX_PHY_REG_CNT - 1);
+	ut_asserteq(reg, (u16)MDIO_MUX_SELECT_NONE);
+
+	return 0;
+}
+
+DM_TEST(dm_test_mdio_mux, DM_TESTF_SCAN_FDT);