// 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; } static int mdio_mux_read_c45(struct mii_bus *bus, int phy_id, int dev_addr, 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_c45(pb->mii_bus, phy_id, dev_addr, 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 mdio_mux_write_c45(struct mii_bus *bus, int phy_id, int dev_addr, 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_c45(pb->mii_bus, phy_id, dev_addr, regnum, val); out: mutex_unlock(&pb->mii_bus->mdio_lock); return r; } static int parent_count; static void mdio_mux_uninit_children(struct mdio_mux_parent_bus *pb) { struct mdio_mux_child_bus *cb = pb->children; while (cb) { mdiobus_unregister(cb->mii_bus); mdiobus_free(cb->mii_bus); cb = cb->next; } } 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; goto err_loop; } cb->bus_number = v; cb->parent = pb; cb->mii_bus = mdiobus_alloc(); if (!cb->mii_bus) { ret_val = -ENOMEM; goto err_loop; } cb->mii_bus->priv = cb; cb->mii_bus->name = "mdio_mux"; snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%s-%x.%x", cb->mii_bus->name, pb->parent_id, v); cb->mii_bus->parent = dev; cb->mii_bus->read = mdio_mux_read; cb->mii_bus->write = mdio_mux_write; if (parent_bus->read_c45) cb->mii_bus->read_c45 = mdio_mux_read_c45; if (parent_bus->write_c45) cb->mii_bus->write_c45 = mdio_mux_write_c45; r = of_mdiobus_register(cb->mii_bus, child_bus_node); if (r) { mdiobus_free(cb->mii_bus); if (r == -EPROBE_DEFER) { ret_val = r; goto err_loop; } devm_kfree(dev, cb); dev_err(dev, "Error: Failed to register MDIO bus for child %pOF\n", child_bus_node); } 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"); err_loop: mdio_mux_uninit_children(pb); of_node_put(child_bus_node); 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; mdio_mux_uninit_children(pb); put_device(&pb->mii_bus->dev); } EXPORT_SYMBOL_GPL(mdio_mux_uninit); MODULE_DESCRIPTION(DRV_DESCRIPTION); MODULE_AUTHOR("David Daney"); MODULE_LICENSE("GPL v2");