tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2011, 2012 Cavium, Inc.
7 */
8
9#include <linux/platform_device.h>
10#include <linux/mdio-mux.h>
11#include <linux/of_mdio.h>
12#include <linux/device.h>
13#include <linux/module.h>
14#include <linux/phy.h>
15
16#define DRV_VERSION "1.0"
17#define DRV_DESCRIPTION "MDIO bus multiplexer driver"
18
19struct mdio_mux_child_bus;
20
21struct mdio_mux_parent_bus {
22 struct mii_bus *mii_bus;
23 int current_child;
24 int parent_id;
25 void *switch_data;
26 int (*switch_fn)(int current_child, int desired_child, void *data);
27
28 /* List of our children linked through their next fields. */
29 struct mdio_mux_child_bus *children;
30};
31
32struct mdio_mux_child_bus {
33 struct mii_bus *mii_bus;
34 struct mdio_mux_parent_bus *parent;
35 struct mdio_mux_child_bus *next;
36 int bus_number;
37};
38
39/*
40 * The parent bus' lock is used to order access to the switch_fn.
41 */
42static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum)
43{
44 struct mdio_mux_child_bus *cb = bus->priv;
45 struct mdio_mux_parent_bus *pb = cb->parent;
46 int r;
47
48 mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
49 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
50 if (r)
51 goto out;
52
53 pb->current_child = cb->bus_number;
54
55 r = pb->mii_bus->read(pb->mii_bus, phy_id, regnum);
56out:
57 mutex_unlock(&pb->mii_bus->mdio_lock);
58
59 return r;
60}
61
62/*
63 * The parent bus' lock is used to order access to the switch_fn.
64 */
65static int mdio_mux_write(struct mii_bus *bus, int phy_id,
66 int regnum, u16 val)
67{
68 struct mdio_mux_child_bus *cb = bus->priv;
69 struct mdio_mux_parent_bus *pb = cb->parent;
70
71 int r;
72
73 mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
74 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
75 if (r)
76 goto out;
77
78 pb->current_child = cb->bus_number;
79
80 r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val);
81out:
82 mutex_unlock(&pb->mii_bus->mdio_lock);
83
84 return r;
85}
86
87static int parent_count;
88
89int mdio_mux_init(struct device *dev,
90 int (*switch_fn)(int cur, int desired, void *data),
91 void **mux_handle,
92 void *data)
93{
94 struct device_node *parent_bus_node;
95 struct device_node *child_bus_node;
96 int r, ret_val;
97 struct mii_bus *parent_bus;
98 struct mdio_mux_parent_bus *pb;
99 struct mdio_mux_child_bus *cb;
100
101 if (!dev->of_node)
102 return -ENODEV;
103
104 parent_bus_node = of_parse_phandle(dev->of_node, "mdio-parent-bus", 0);
105
106 if (!parent_bus_node)
107 return -ENODEV;
108
109 pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
110 if (pb == NULL) {
111 ret_val = -ENOMEM;
112 goto err_parent_bus;
113 }
114
115 parent_bus = of_mdio_find_bus(parent_bus_node);
116 if (parent_bus == NULL) {
117 ret_val = -EPROBE_DEFER;
118 goto err_parent_bus;
119 }
120
121 pb->switch_data = data;
122 pb->switch_fn = switch_fn;
123 pb->current_child = -1;
124 pb->parent_id = parent_count++;
125 pb->mii_bus = parent_bus;
126
127 ret_val = -ENODEV;
128 for_each_available_child_of_node(dev->of_node, child_bus_node) {
129 u32 v;
130
131 r = of_property_read_u32(child_bus_node, "reg", &v);
132 if (r)
133 continue;
134
135 cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
136 if (cb == NULL) {
137 dev_err(dev,
138 "Error: Failed to allocate memory for child\n");
139 ret_val = -ENOMEM;
140 of_node_put(child_bus_node);
141 break;
142 }
143 cb->bus_number = v;
144 cb->parent = pb;
145
146 cb->mii_bus = mdiobus_alloc();
147 if (!cb->mii_bus) {
148 ret_val = -ENOMEM;
149 of_node_put(child_bus_node);
150 break;
151 }
152 cb->mii_bus->priv = cb;
153
154 cb->mii_bus->name = "mdio_mux";
155 snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%x.%x",
156 pb->parent_id, v);
157 cb->mii_bus->parent = dev;
158 cb->mii_bus->read = mdio_mux_read;
159 cb->mii_bus->write = mdio_mux_write;
160 r = of_mdiobus_register(cb->mii_bus, child_bus_node);
161 if (r) {
162 mdiobus_free(cb->mii_bus);
163 devm_kfree(dev, cb);
164 } else {
165 of_node_get(child_bus_node);
166 cb->next = pb->children;
167 pb->children = cb;
168 }
169 }
170 if (pb->children) {
171 *mux_handle = pb;
172 dev_info(dev, "Version " DRV_VERSION "\n");
173 return 0;
174 }
175
176 /* balance the reference of_mdio_find_bus() took */
177 put_device(&pb->mii_bus->dev);
178
179err_parent_bus:
180 of_node_put(parent_bus_node);
181 return ret_val;
182}
183EXPORT_SYMBOL_GPL(mdio_mux_init);
184
185void mdio_mux_uninit(void *mux_handle)
186{
187 struct mdio_mux_parent_bus *pb = mux_handle;
188 struct mdio_mux_child_bus *cb = pb->children;
189
190 while (cb) {
191 mdiobus_unregister(cb->mii_bus);
192 mdiobus_free(cb->mii_bus);
193 cb = cb->next;
194 }
195
196 /* balance the reference of_mdio_find_bus() in mdio_mux_init() took */
197 put_device(&pb->mii_bus->dev);
198}
199EXPORT_SYMBOL_GPL(mdio_mux_uninit);
200
201MODULE_DESCRIPTION(DRV_DESCRIPTION);
202MODULE_VERSION(DRV_VERSION);
203MODULE_AUTHOR("David Daney");
204MODULE_LICENSE("GPL");