1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2011, 2012 Cavium, Inc.
*/
#include <linux/platform_device.h>
#include <linux/mdio-mux.h>
#include <linux/of_mdio.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/phy.h>
#define DRV_VERSION "1.0"
#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;
/* In theory multiple mdio_mux could be stacked, thus creating
* more than a single level of nesting. But in practice,
* SINGLE_DEPTH_NESTING will cover the vast majority of use
* cases. We use it, instead of trying to handle the general
* case.
*/
mutex_lock_nested(&pb->mii_bus->mdio_lock, SINGLE_DEPTH_NESTING);
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, SINGLE_DEPTH_NESTING);
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,
int (*switch_fn)(int cur, int desired, void *data),
void **mux_handle,
void *data)
{
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 (!dev->of_node)
return -ENODEV;
parent_bus_node = of_parse_phandle(dev->of_node, "mdio-parent-bus", 0);
if (!parent_bus_node)
return -ENODEV;
pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
if (pb == NULL) {
ret_val = -ENOMEM;
goto err_parent_bus;
}
parent_bus = of_mdio_find_bus(parent_bus_node);
if (parent_bus == NULL) {
ret_val = -EPROBE_DEFER;
goto err_parent_bus;
}
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(dev->of_node, child_bus_node) {
u32 v;
r = of_property_read_u32(child_bus_node, "reg", &v);
if (r)
continue;
cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
if (cb == NULL) {
dev_err(dev,
"Error: Failed to allocate memory for child\n");
ret_val = -ENOMEM;
of_node_put(child_bus_node);
break;
}
cb->bus_number = v;
cb->parent = pb;
cb->mii_bus = mdiobus_alloc();
if (!cb->mii_bus) {
ret_val = -ENOMEM;
of_node_put(child_bus_node);
break;
}
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);
devm_kfree(dev, cb);
} else {
of_node_get(child_bus_node);
cb->next = pb->children;
pb->children = cb;
}
}
if (pb->children) {
*mux_handle = pb;
dev_info(dev, "Version " DRV_VERSION "\n");
return 0;
}
/* balance the reference of_mdio_find_bus() took */
put_device(&pb->mii_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;
}
/* balance the reference of_mdio_find_bus() in mdio_mux_init() took */
put_device(&pb->mii_bus->dev);
}
EXPORT_SYMBOL_GPL(mdio_mux_uninit);
MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_VERSION(DRV_VERSION);
MODULE_AUTHOR("David Daney");
MODULE_LICENSE("GPL");
|
