v4.19.13 snapshot.
diff --git a/drivers/net/phy/mdio-mux.c b/drivers/net/phy/mdio-mux.c
new file mode 100644
index 0000000..0a86f1e
--- /dev/null
+++ b/drivers/net/phy/mdio-mux.c
@@ -0,0 +1,213 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2011, 2012 Cavium, Inc.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/mdio-mux.h>
+#include <linux/of_mdio.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/phy.h>
+
+#define DRV_DESCRIPTION "MDIO bus multiplexer driver"
+
+struct mdio_mux_child_bus;
+
+struct mdio_mux_parent_bus {
+ struct mii_bus *mii_bus;
+ int current_child;
+ int parent_id;
+ void *switch_data;
+ int (*switch_fn)(int current_child, int desired_child, void *data);
+
+ /* List of our children linked through their next fields. */
+ struct mdio_mux_child_bus *children;
+};
+
+struct mdio_mux_child_bus {
+ struct mii_bus *mii_bus;
+ struct mdio_mux_parent_bus *parent;
+ struct mdio_mux_child_bus *next;
+ int bus_number;
+};
+
+/*
+ * The parent bus' lock is used to order access to the switch_fn.
+ */
+static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum)
+{
+ struct mdio_mux_child_bus *cb = bus->priv;
+ struct mdio_mux_parent_bus *pb = cb->parent;
+ int r;
+
+ mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
+ r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
+ if (r)
+ goto out;
+
+ pb->current_child = cb->bus_number;
+
+ r = pb->mii_bus->read(pb->mii_bus, phy_id, regnum);
+out:
+ mutex_unlock(&pb->mii_bus->mdio_lock);
+
+ return r;
+}
+
+/*
+ * The parent bus' lock is used to order access to the switch_fn.
+ */
+static int mdio_mux_write(struct mii_bus *bus, int phy_id,
+ int regnum, u16 val)
+{
+ struct mdio_mux_child_bus *cb = bus->priv;
+ struct mdio_mux_parent_bus *pb = cb->parent;
+
+ int r;
+
+ mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
+ r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
+ if (r)
+ goto out;
+
+ pb->current_child = cb->bus_number;
+
+ r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val);
+out:
+ mutex_unlock(&pb->mii_bus->mdio_lock);
+
+ return r;
+}
+
+static int parent_count;
+
+int mdio_mux_init(struct device *dev,
+ struct device_node *mux_node,
+ int (*switch_fn)(int cur, int desired, void *data),
+ void **mux_handle,
+ void *data,
+ struct mii_bus *mux_bus)
+{
+ struct device_node *parent_bus_node;
+ struct device_node *child_bus_node;
+ int r, ret_val;
+ struct mii_bus *parent_bus;
+ struct mdio_mux_parent_bus *pb;
+ struct mdio_mux_child_bus *cb;
+
+ if (!mux_node)
+ return -ENODEV;
+
+ if (!mux_bus) {
+ parent_bus_node = of_parse_phandle(mux_node,
+ "mdio-parent-bus", 0);
+
+ if (!parent_bus_node)
+ return -ENODEV;
+
+ parent_bus = of_mdio_find_bus(parent_bus_node);
+ if (!parent_bus) {
+ ret_val = -EPROBE_DEFER;
+ goto err_parent_bus;
+ }
+ } else {
+ parent_bus_node = NULL;
+ parent_bus = mux_bus;
+ get_device(&parent_bus->dev);
+ }
+
+ pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
+ if (!pb) {
+ ret_val = -ENOMEM;
+ goto err_pb_kz;
+ }
+
+ pb->switch_data = data;
+ pb->switch_fn = switch_fn;
+ pb->current_child = -1;
+ pb->parent_id = parent_count++;
+ pb->mii_bus = parent_bus;
+
+ ret_val = -ENODEV;
+ for_each_available_child_of_node(mux_node, child_bus_node) {
+ int v;
+
+ r = of_property_read_u32(child_bus_node, "reg", &v);
+ if (r) {
+ dev_err(dev,
+ "Error: Failed to find reg for child %pOF\n",
+ child_bus_node);
+ continue;
+ }
+
+ cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
+ if (!cb) {
+ ret_val = -ENOMEM;
+ continue;
+ }
+ cb->bus_number = v;
+ cb->parent = pb;
+
+ cb->mii_bus = mdiobus_alloc();
+ if (!cb->mii_bus) {
+ ret_val = -ENOMEM;
+ devm_kfree(dev, cb);
+ continue;
+ }
+ cb->mii_bus->priv = cb;
+
+ cb->mii_bus->name = "mdio_mux";
+ snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%x.%x",
+ pb->parent_id, v);
+ cb->mii_bus->parent = dev;
+ cb->mii_bus->read = mdio_mux_read;
+ cb->mii_bus->write = mdio_mux_write;
+ r = of_mdiobus_register(cb->mii_bus, child_bus_node);
+ if (r) {
+ dev_err(dev,
+ "Error: Failed to register MDIO bus for child %pOF\n",
+ child_bus_node);
+ mdiobus_free(cb->mii_bus);
+ devm_kfree(dev, cb);
+ } else {
+ cb->next = pb->children;
+ pb->children = cb;
+ }
+ }
+ if (pb->children) {
+ *mux_handle = pb;
+ return 0;
+ }
+
+ dev_err(dev, "Error: No acceptable child buses found\n");
+ devm_kfree(dev, pb);
+err_pb_kz:
+ put_device(&parent_bus->dev);
+err_parent_bus:
+ of_node_put(parent_bus_node);
+ return ret_val;
+}
+EXPORT_SYMBOL_GPL(mdio_mux_init);
+
+void mdio_mux_uninit(void *mux_handle)
+{
+ struct mdio_mux_parent_bus *pb = mux_handle;
+ struct mdio_mux_child_bus *cb = pb->children;
+
+ while (cb) {
+ mdiobus_unregister(cb->mii_bus);
+ mdiobus_free(cb->mii_bus);
+ cb = cb->next;
+ }
+
+ put_device(&pb->mii_bus->dev);
+}
+EXPORT_SYMBOL_GPL(mdio_mux_uninit);
+
+MODULE_DESCRIPTION(DRV_DESCRIPTION);
+MODULE_AUTHOR("David Daney");
+MODULE_LICENSE("GPL");