| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 2011, 2012 Cavium, Inc. |
| */ |
| |
| #include <linux/device.h> |
| #include <linux/mdio-mux.h> |
| #include <linux/module.h> |
| #include <linux/of_mdio.h> |
| #include <linux/phy.h> |
| #include <linux/platform_device.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 v2"); |