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 struct mii_bus *mux_bus)
94{
95 struct device_node *parent_bus_node;
96 struct device_node *child_bus_node;
97 int r, ret_val;
98 struct mii_bus *parent_bus;
99 struct mdio_mux_parent_bus *pb;
100 struct mdio_mux_child_bus *cb;
101
102 if (!dev->of_node)
103 return -ENODEV;
104
105 if (!mux_bus) {
106 parent_bus_node = of_parse_phandle(dev->of_node,
107 "mdio-parent-bus", 0);
108
109 if (!parent_bus_node)
110 return -ENODEV;
111
112 parent_bus = of_mdio_find_bus(parent_bus_node);
113 if (!parent_bus) {
114 ret_val = -EPROBE_DEFER;
115 goto err_parent_bus;
116 }
117 } else {
118 parent_bus_node = NULL;
119 parent_bus = mux_bus;
120 }
121
122 pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
123 if (pb == NULL) {
124 ret_val = -ENOMEM;
125 goto err_parent_bus;
126 }
127
128
129 pb->switch_data = data;
130 pb->switch_fn = switch_fn;
131 pb->current_child = -1;
132 pb->parent_id = parent_count++;
133 pb->mii_bus = parent_bus;
134
135 ret_val = -ENODEV;
136 for_each_available_child_of_node(dev->of_node, child_bus_node) {
137 u32 v;
138
139 r = of_property_read_u32(child_bus_node, "reg", &v);
140 if (r)
141 continue;
142
143 cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
144 if (cb == NULL) {
145 dev_err(dev,
146 "Error: Failed to allocate memory for child\n");
147 ret_val = -ENOMEM;
148 of_node_put(child_bus_node);
149 break;
150 }
151 cb->bus_number = v;
152 cb->parent = pb;
153
154 cb->mii_bus = mdiobus_alloc();
155 if (!cb->mii_bus) {
156 ret_val = -ENOMEM;
157 of_node_put(child_bus_node);
158 break;
159 }
160 cb->mii_bus->priv = cb;
161
162 cb->mii_bus->name = "mdio_mux";
163 snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%x.%x",
164 pb->parent_id, v);
165 cb->mii_bus->parent = dev;
166 cb->mii_bus->read = mdio_mux_read;
167 cb->mii_bus->write = mdio_mux_write;
168 r = of_mdiobus_register(cb->mii_bus, child_bus_node);
169 if (r) {
170 mdiobus_free(cb->mii_bus);
171 devm_kfree(dev, cb);
172 } else {
173 of_node_get(child_bus_node);
174 cb->next = pb->children;
175 pb->children = cb;
176 }
177 }
178 if (pb->children) {
179 *mux_handle = pb;
180 dev_info(dev, "Version " DRV_VERSION "\n");
181 return 0;
182 }
183
184 /* balance the reference of_mdio_find_bus() took */
185 put_device(&pb->mii_bus->dev);
186
187err_parent_bus:
188 of_node_put(parent_bus_node);
189 return ret_val;
190}
191EXPORT_SYMBOL_GPL(mdio_mux_init);
192
193void mdio_mux_uninit(void *mux_handle)
194{
195 struct mdio_mux_parent_bus *pb = mux_handle;
196 struct mdio_mux_child_bus *cb = pb->children;
197
198 while (cb) {
199 mdiobus_unregister(cb->mii_bus);
200 mdiobus_free(cb->mii_bus);
201 cb = cb->next;
202 }
203
204 /* balance the reference of_mdio_find_bus() in mdio_mux_init() took */
205 put_device(&pb->mii_bus->dev);
206}
207EXPORT_SYMBOL_GPL(mdio_mux_uninit);
208
209MODULE_DESCRIPTION(DRV_DESCRIPTION);
210MODULE_VERSION(DRV_VERSION);
211MODULE_AUTHOR("David Daney");
212MODULE_LICENSE("GPL");