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![Timur Tabi](/assets/img/avatar_default.png)
The mdio-mux driver scans all child mdio nodes, without regard to whether the node is actually used. Some device trees include all possible mdio-mux nodes and rely on the boot loader to disable those that are not present, based on some run-time configuration. Those nodes need to be skipped. Signed-off-by: Timur Tabi <timur@freescale.com> Signed-off-by: David S. Miller <davem@davemloft.net>
198 lines
4.6 KiB
C
198 lines
4.6 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2011, 2012 Cavium, Inc.
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*/
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#include <linux/platform_device.h>
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#include <linux/mdio-mux.h>
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#include <linux/of_mdio.h>
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#include <linux/device.h>
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#include <linux/module.h>
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#include <linux/phy.h>
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#define DRV_VERSION "1.0"
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#define DRV_DESCRIPTION "MDIO bus multiplexer driver"
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struct mdio_mux_child_bus;
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struct mdio_mux_parent_bus {
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struct mii_bus *mii_bus;
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int current_child;
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int parent_id;
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void *switch_data;
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int (*switch_fn)(int current_child, int desired_child, void *data);
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/* List of our children linked through their next fields. */
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struct mdio_mux_child_bus *children;
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};
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struct mdio_mux_child_bus {
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struct mii_bus *mii_bus;
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struct mdio_mux_parent_bus *parent;
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struct mdio_mux_child_bus *next;
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int bus_number;
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int phy_irq[PHY_MAX_ADDR];
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};
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/*
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* The parent bus' lock is used to order access to the switch_fn.
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*/
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static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum)
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{
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struct mdio_mux_child_bus *cb = bus->priv;
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struct mdio_mux_parent_bus *pb = cb->parent;
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int r;
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/* In theory multiple mdio_mux could be stacked, thus creating
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* more than a single level of nesting. But in practice,
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* SINGLE_DEPTH_NESTING will cover the vast majority of use
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* cases. We use it, instead of trying to handle the general
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* case.
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*/
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mutex_lock_nested(&pb->mii_bus->mdio_lock, SINGLE_DEPTH_NESTING);
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r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
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if (r)
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goto out;
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pb->current_child = cb->bus_number;
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r = pb->mii_bus->read(pb->mii_bus, phy_id, regnum);
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out:
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mutex_unlock(&pb->mii_bus->mdio_lock);
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return r;
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}
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/*
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* The parent bus' lock is used to order access to the switch_fn.
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*/
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static int mdio_mux_write(struct mii_bus *bus, int phy_id,
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int regnum, u16 val)
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{
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struct mdio_mux_child_bus *cb = bus->priv;
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struct mdio_mux_parent_bus *pb = cb->parent;
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int r;
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mutex_lock_nested(&pb->mii_bus->mdio_lock, SINGLE_DEPTH_NESTING);
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r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
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if (r)
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goto out;
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pb->current_child = cb->bus_number;
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r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val);
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out:
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mutex_unlock(&pb->mii_bus->mdio_lock);
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return r;
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}
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static int parent_count;
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int mdio_mux_init(struct device *dev,
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int (*switch_fn)(int cur, int desired, void *data),
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void **mux_handle,
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void *data)
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{
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struct device_node *parent_bus_node;
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struct device_node *child_bus_node;
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int r, ret_val;
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struct mii_bus *parent_bus;
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struct mdio_mux_parent_bus *pb;
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struct mdio_mux_child_bus *cb;
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if (!dev->of_node)
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return -ENODEV;
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parent_bus_node = of_parse_phandle(dev->of_node, "mdio-parent-bus", 0);
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if (!parent_bus_node)
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return -ENODEV;
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parent_bus = of_mdio_find_bus(parent_bus_node);
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if (parent_bus == NULL) {
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ret_val = -EPROBE_DEFER;
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goto err_parent_bus;
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}
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pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
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if (pb == NULL) {
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ret_val = -ENOMEM;
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goto err_parent_bus;
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}
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pb->switch_data = data;
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pb->switch_fn = switch_fn;
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pb->current_child = -1;
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pb->parent_id = parent_count++;
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pb->mii_bus = parent_bus;
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ret_val = -ENODEV;
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for_each_available_child_of_node(dev->of_node, child_bus_node) {
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u32 v;
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r = of_property_read_u32(child_bus_node, "reg", &v);
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if (r)
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continue;
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cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
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if (cb == NULL) {
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dev_err(dev,
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"Error: Failed to allocate memory for child\n");
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ret_val = -ENOMEM;
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break;
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}
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cb->bus_number = v;
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cb->parent = pb;
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cb->mii_bus = mdiobus_alloc();
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cb->mii_bus->priv = cb;
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cb->mii_bus->irq = cb->phy_irq;
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cb->mii_bus->name = "mdio_mux";
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snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%x.%x",
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pb->parent_id, v);
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cb->mii_bus->parent = dev;
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cb->mii_bus->read = mdio_mux_read;
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cb->mii_bus->write = mdio_mux_write;
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r = of_mdiobus_register(cb->mii_bus, child_bus_node);
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if (r) {
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mdiobus_free(cb->mii_bus);
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devm_kfree(dev, cb);
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} else {
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of_node_get(child_bus_node);
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cb->next = pb->children;
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pb->children = cb;
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}
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}
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if (pb->children) {
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*mux_handle = pb;
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dev_info(dev, "Version " DRV_VERSION "\n");
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return 0;
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}
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err_parent_bus:
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of_node_put(parent_bus_node);
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return ret_val;
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}
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EXPORT_SYMBOL_GPL(mdio_mux_init);
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void mdio_mux_uninit(void *mux_handle)
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{
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struct mdio_mux_parent_bus *pb = mux_handle;
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struct mdio_mux_child_bus *cb = pb->children;
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while (cb) {
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mdiobus_unregister(cb->mii_bus);
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mdiobus_free(cb->mii_bus);
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cb = cb->next;
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}
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}
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EXPORT_SYMBOL_GPL(mdio_mux_uninit);
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MODULE_DESCRIPTION(DRV_DESCRIPTION);
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MODULE_VERSION(DRV_VERSION);
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MODULE_AUTHOR("David Daney");
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MODULE_LICENSE("GPL");
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