diff options
Diffstat (limited to 'drivers/net/mdio/mdio-mux.c')
| -rw-r--r-- | drivers/net/mdio/mdio-mux.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/drivers/net/mdio/mdio-mux.c b/drivers/net/mdio/mdio-mux.c new file mode 100644 index 000000000..3dde0c2b3 --- /dev/null +++ b/drivers/net/mdio/mdio-mux.c @@ -0,0 +1,222 @@ +// 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; + +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, "%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) { + 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"); + devm_kfree(dev, pb); + +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"); |