v4.19.13 snapshot.
diff --git a/drivers/net/phy/fixed_phy.c b/drivers/net/phy/fixed_phy.c
new file mode 100644
index 0000000..67b2608
--- /dev/null
+++ b/drivers/net/phy/fixed_phy.c
@@ -0,0 +1,311 @@
+/*
+ * Fixed MDIO bus (MDIO bus emulation with fixed PHYs)
+ *
+ * Author: Vitaly Bordug <vbordug@ru.mvista.com>
+ *         Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * Copyright (c) 2006-2007 MontaVista Software, Inc.
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/list.h>
+#include <linux/mii.h>
+#include <linux/phy.h>
+#include <linux/phy_fixed.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/gpio.h>
+#include <linux/seqlock.h>
+#include <linux/idr.h>
+
+#include "swphy.h"
+
+struct fixed_mdio_bus {
+	struct mii_bus *mii_bus;
+	struct list_head phys;
+};
+
+struct fixed_phy {
+	int addr;
+	struct phy_device *phydev;
+	seqcount_t seqcount;
+	struct fixed_phy_status status;
+	int (*link_update)(struct net_device *, struct fixed_phy_status *);
+	struct list_head node;
+	int link_gpio;
+};
+
+static struct platform_device *pdev;
+static struct fixed_mdio_bus platform_fmb = {
+	.phys = LIST_HEAD_INIT(platform_fmb.phys),
+};
+
+static void fixed_phy_update(struct fixed_phy *fp)
+{
+	if (gpio_is_valid(fp->link_gpio))
+		fp->status.link = !!gpio_get_value_cansleep(fp->link_gpio);
+}
+
+static int fixed_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
+{
+	struct fixed_mdio_bus *fmb = bus->priv;
+	struct fixed_phy *fp;
+
+	list_for_each_entry(fp, &fmb->phys, node) {
+		if (fp->addr == phy_addr) {
+			struct fixed_phy_status state;
+			int s;
+
+			do {
+				s = read_seqcount_begin(&fp->seqcount);
+				/* Issue callback if user registered it. */
+				if (fp->link_update) {
+					fp->link_update(fp->phydev->attached_dev,
+							&fp->status);
+					fixed_phy_update(fp);
+				}
+				state = fp->status;
+			} while (read_seqcount_retry(&fp->seqcount, s));
+
+			return swphy_read_reg(reg_num, &state);
+		}
+	}
+
+	return 0xFFFF;
+}
+
+static int fixed_mdio_write(struct mii_bus *bus, int phy_addr, int reg_num,
+			    u16 val)
+{
+	return 0;
+}
+
+/*
+ * If something weird is required to be done with link/speed,
+ * network driver is able to assign a function to implement this.
+ * May be useful for PHY's that need to be software-driven.
+ */
+int fixed_phy_set_link_update(struct phy_device *phydev,
+			      int (*link_update)(struct net_device *,
+						 struct fixed_phy_status *))
+{
+	struct fixed_mdio_bus *fmb = &platform_fmb;
+	struct fixed_phy *fp;
+
+	if (!phydev || !phydev->mdio.bus)
+		return -EINVAL;
+
+	list_for_each_entry(fp, &fmb->phys, node) {
+		if (fp->addr == phydev->mdio.addr) {
+			fp->link_update = link_update;
+			fp->phydev = phydev;
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+EXPORT_SYMBOL_GPL(fixed_phy_set_link_update);
+
+int fixed_phy_add(unsigned int irq, int phy_addr,
+		  struct fixed_phy_status *status,
+		  int link_gpio)
+{
+	int ret;
+	struct fixed_mdio_bus *fmb = &platform_fmb;
+	struct fixed_phy *fp;
+
+	ret = swphy_validate_state(status);
+	if (ret < 0)
+		return ret;
+
+	fp = kzalloc(sizeof(*fp), GFP_KERNEL);
+	if (!fp)
+		return -ENOMEM;
+
+	seqcount_init(&fp->seqcount);
+
+	if (irq != PHY_POLL)
+		fmb->mii_bus->irq[phy_addr] = irq;
+
+	fp->addr = phy_addr;
+	fp->status = *status;
+	fp->link_gpio = link_gpio;
+
+	if (gpio_is_valid(fp->link_gpio)) {
+		ret = gpio_request_one(fp->link_gpio, GPIOF_DIR_IN,
+				       "fixed-link-gpio-link");
+		if (ret)
+			goto err_regs;
+	}
+
+	fixed_phy_update(fp);
+
+	list_add_tail(&fp->node, &fmb->phys);
+
+	return 0;
+
+err_regs:
+	kfree(fp);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(fixed_phy_add);
+
+static DEFINE_IDA(phy_fixed_ida);
+
+static void fixed_phy_del(int phy_addr)
+{
+	struct fixed_mdio_bus *fmb = &platform_fmb;
+	struct fixed_phy *fp, *tmp;
+
+	list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
+		if (fp->addr == phy_addr) {
+			list_del(&fp->node);
+			if (gpio_is_valid(fp->link_gpio))
+				gpio_free(fp->link_gpio);
+			kfree(fp);
+			ida_simple_remove(&phy_fixed_ida, phy_addr);
+			return;
+		}
+	}
+}
+
+struct phy_device *fixed_phy_register(unsigned int irq,
+				      struct fixed_phy_status *status,
+				      int link_gpio,
+				      struct device_node *np)
+{
+	struct fixed_mdio_bus *fmb = &platform_fmb;
+	struct phy_device *phy;
+	int phy_addr;
+	int ret;
+
+	if (!fmb->mii_bus || fmb->mii_bus->state != MDIOBUS_REGISTERED)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	/* Get the next available PHY address, up to PHY_MAX_ADDR */
+	phy_addr = ida_simple_get(&phy_fixed_ida, 0, PHY_MAX_ADDR, GFP_KERNEL);
+	if (phy_addr < 0)
+		return ERR_PTR(phy_addr);
+
+	ret = fixed_phy_add(irq, phy_addr, status, link_gpio);
+	if (ret < 0) {
+		ida_simple_remove(&phy_fixed_ida, phy_addr);
+		return ERR_PTR(ret);
+	}
+
+	phy = get_phy_device(fmb->mii_bus, phy_addr, false);
+	if (IS_ERR(phy)) {
+		fixed_phy_del(phy_addr);
+		return ERR_PTR(-EINVAL);
+	}
+
+	/* propagate the fixed link values to struct phy_device */
+	phy->link = status->link;
+	if (status->link) {
+		phy->speed = status->speed;
+		phy->duplex = status->duplex;
+		phy->pause = status->pause;
+		phy->asym_pause = status->asym_pause;
+	}
+
+	of_node_get(np);
+	phy->mdio.dev.of_node = np;
+	phy->is_pseudo_fixed_link = true;
+
+	switch (status->speed) {
+	case SPEED_1000:
+		phy->supported = PHY_1000BT_FEATURES;
+		break;
+	case SPEED_100:
+		phy->supported = PHY_100BT_FEATURES;
+		break;
+	case SPEED_10:
+	default:
+		phy->supported = PHY_10BT_FEATURES;
+	}
+
+	ret = phy_device_register(phy);
+	if (ret) {
+		phy_device_free(phy);
+		of_node_put(np);
+		fixed_phy_del(phy_addr);
+		return ERR_PTR(ret);
+	}
+
+	return phy;
+}
+EXPORT_SYMBOL_GPL(fixed_phy_register);
+
+void fixed_phy_unregister(struct phy_device *phy)
+{
+	phy_device_remove(phy);
+	of_node_put(phy->mdio.dev.of_node);
+	fixed_phy_del(phy->mdio.addr);
+}
+EXPORT_SYMBOL_GPL(fixed_phy_unregister);
+
+static int __init fixed_mdio_bus_init(void)
+{
+	struct fixed_mdio_bus *fmb = &platform_fmb;
+	int ret;
+
+	pdev = platform_device_register_simple("Fixed MDIO bus", 0, NULL, 0);
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	fmb->mii_bus = mdiobus_alloc();
+	if (fmb->mii_bus == NULL) {
+		ret = -ENOMEM;
+		goto err_mdiobus_reg;
+	}
+
+	snprintf(fmb->mii_bus->id, MII_BUS_ID_SIZE, "fixed-0");
+	fmb->mii_bus->name = "Fixed MDIO Bus";
+	fmb->mii_bus->priv = fmb;
+	fmb->mii_bus->parent = &pdev->dev;
+	fmb->mii_bus->read = &fixed_mdio_read;
+	fmb->mii_bus->write = &fixed_mdio_write;
+
+	ret = mdiobus_register(fmb->mii_bus);
+	if (ret)
+		goto err_mdiobus_alloc;
+
+	return 0;
+
+err_mdiobus_alloc:
+	mdiobus_free(fmb->mii_bus);
+err_mdiobus_reg:
+	platform_device_unregister(pdev);
+	return ret;
+}
+module_init(fixed_mdio_bus_init);
+
+static void __exit fixed_mdio_bus_exit(void)
+{
+	struct fixed_mdio_bus *fmb = &platform_fmb;
+	struct fixed_phy *fp, *tmp;
+
+	mdiobus_unregister(fmb->mii_bus);
+	mdiobus_free(fmb->mii_bus);
+	platform_device_unregister(pdev);
+
+	list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
+		list_del(&fp->node);
+		kfree(fp);
+	}
+	ida_destroy(&phy_fixed_ida);
+}
+module_exit(fixed_mdio_bus_exit);
+
+MODULE_DESCRIPTION("Fixed MDIO bus (MDIO bus emulation with fixed PHYs)");
+MODULE_AUTHOR("Vitaly Bordug");
+MODULE_LICENSE("GPL");