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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_DESCRIPTION "MDIO bus multiplexer driver"
17
18struct mdio_mux_child_bus;
19
20struct mdio_mux_parent_bus {
21 struct mii_bus *mii_bus;
22 int current_child;
23 int parent_id;
24 void *switch_data;
25 int (*switch_fn)(int current_child, int desired_child, void *data);
26
27 /* List of our children linked through their next fields. */
28 struct mdio_mux_child_bus *children;
29};
30
31struct mdio_mux_child_bus {
32 struct mii_bus *mii_bus;
33 struct mdio_mux_parent_bus *parent;
34 struct mdio_mux_child_bus *next;
35 int bus_number;
36};
37
38/*
39 * The parent bus' lock is used to order access to the switch_fn.
40 */
41static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum)
42{
43 struct mdio_mux_child_bus *cb = bus->priv;
44 struct mdio_mux_parent_bus *pb = cb->parent;
45 int r;
46
47 mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
48 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
49 if (r)
50 goto out;
51
52 pb->current_child = cb->bus_number;
53
54 r = pb->mii_bus->read(pb->mii_bus, phy_id, regnum);
55out:
56 mutex_unlock(&pb->mii_bus->mdio_lock);
57
58 return r;
59}
60
61/*
62 * The parent bus' lock is used to order access to the switch_fn.
63 */
64static int mdio_mux_write(struct mii_bus *bus, int phy_id,
65 int regnum, u16 val)
66{
67 struct mdio_mux_child_bus *cb = bus->priv;
68 struct mdio_mux_parent_bus *pb = cb->parent;
69
70 int r;
71
72 mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
73 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
74 if (r)
75 goto out;
76
77 pb->current_child = cb->bus_number;
78
79 r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val);
80out:
81 mutex_unlock(&pb->mii_bus->mdio_lock);
82
83 return r;
84}
85
86static int parent_count;
87
88int mdio_mux_init(struct device *dev,
89 struct device_node *mux_node,
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 (!mux_node)
103 return -ENODEV;
104
105 if (!mux_bus) {
106 parent_bus_node = of_parse_phandle(mux_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 get_device(&parent_bus->dev);
121 }
122
123 pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
124 if (!pb) {
125 ret_val = -ENOMEM;
126 goto err_pb_kz;
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(mux_node, child_bus_node) {
137 int v;
138
139 r = of_property_read_u32(child_bus_node, "reg", &v);
140 if (r) {
141 dev_err(dev,
142 "Error: Failed to find reg for child %pOF\n",
143 child_bus_node);
144 continue;
145 }
146
147 cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
148 if (!cb) {
149 ret_val = -ENOMEM;
150 continue;
151 }
152 cb->bus_number = v;
153 cb->parent = pb;
154
155 cb->mii_bus = mdiobus_alloc();
156 if (!cb->mii_bus) {
157 ret_val = -ENOMEM;
158 devm_kfree(dev, cb);
159 continue;
160 }
161 cb->mii_bus->priv = cb;
162
163 cb->mii_bus->name = "mdio_mux";
164 snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%x.%x",
165 pb->parent_id, v);
166 cb->mii_bus->parent = dev;
167 cb->mii_bus->read = mdio_mux_read;
168 cb->mii_bus->write = mdio_mux_write;
169 r = of_mdiobus_register(cb->mii_bus, child_bus_node);
170 if (r) {
171 dev_err(dev,
172 "Error: Failed to register MDIO bus for child %pOF\n",
173 child_bus_node);
174 mdiobus_free(cb->mii_bus);
175 devm_kfree(dev, cb);
176 } else {
177 cb->next = pb->children;
178 pb->children = cb;
179 }
180 }
181 if (pb->children) {
182 *mux_handle = pb;
183 return 0;
184 }
185
186 dev_err(dev, "Error: No acceptable child buses found\n");
187 devm_kfree(dev, pb);
188err_pb_kz:
189 put_device(&parent_bus->dev);
190err_parent_bus:
191 of_node_put(parent_bus_node);
192 return ret_val;
193}
194EXPORT_SYMBOL_GPL(mdio_mux_init);
195
196void mdio_mux_uninit(void *mux_handle)
197{
198 struct mdio_mux_parent_bus *pb = mux_handle;
199 struct mdio_mux_child_bus *cb = pb->children;
200
201 while (cb) {
202 mdiobus_unregister(cb->mii_bus);
203 mdiobus_free(cb->mii_bus);
204 cb = cb->next;
205 }
206
207 put_device(&pb->mii_bus->dev);
208}
209EXPORT_SYMBOL_GPL(mdio_mux_uninit);
210
211MODULE_DESCRIPTION(DRV_DESCRIPTION);
212MODULE_AUTHOR("David Daney");
213MODULE_LICENSE("GPL");
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 /* In theory multiple mdio_mux could be stacked, thus creating
49 * more than a single level of nesting. But in practice,
50 * SINGLE_DEPTH_NESTING will cover the vast majority of use
51 * cases. We use it, instead of trying to handle the general
52 * case.
53 */
54 mutex_lock_nested(&pb->mii_bus->mdio_lock, SINGLE_DEPTH_NESTING);
55 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
56 if (r)
57 goto out;
58
59 pb->current_child = cb->bus_number;
60
61 r = pb->mii_bus->read(pb->mii_bus, phy_id, regnum);
62out:
63 mutex_unlock(&pb->mii_bus->mdio_lock);
64
65 return r;
66}
67
68/*
69 * The parent bus' lock is used to order access to the switch_fn.
70 */
71static int mdio_mux_write(struct mii_bus *bus, int phy_id,
72 int regnum, u16 val)
73{
74 struct mdio_mux_child_bus *cb = bus->priv;
75 struct mdio_mux_parent_bus *pb = cb->parent;
76
77 int r;
78
79 mutex_lock_nested(&pb->mii_bus->mdio_lock, SINGLE_DEPTH_NESTING);
80 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
81 if (r)
82 goto out;
83
84 pb->current_child = cb->bus_number;
85
86 r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val);
87out:
88 mutex_unlock(&pb->mii_bus->mdio_lock);
89
90 return r;
91}
92
93static int parent_count;
94
95int mdio_mux_init(struct device *dev,
96 int (*switch_fn)(int cur, int desired, void *data),
97 void **mux_handle,
98 void *data)
99{
100 struct device_node *parent_bus_node;
101 struct device_node *child_bus_node;
102 int r, ret_val;
103 struct mii_bus *parent_bus;
104 struct mdio_mux_parent_bus *pb;
105 struct mdio_mux_child_bus *cb;
106
107 if (!dev->of_node)
108 return -ENODEV;
109
110 parent_bus_node = of_parse_phandle(dev->of_node, "mdio-parent-bus", 0);
111
112 if (!parent_bus_node)
113 return -ENODEV;
114
115 pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
116 if (pb == NULL) {
117 ret_val = -ENOMEM;
118 goto err_parent_bus;
119 }
120
121 parent_bus = of_mdio_find_bus(parent_bus_node);
122 if (parent_bus == NULL) {
123 ret_val = -EPROBE_DEFER;
124 goto err_parent_bus;
125 }
126
127 pb->switch_data = data;
128 pb->switch_fn = switch_fn;
129 pb->current_child = -1;
130 pb->parent_id = parent_count++;
131 pb->mii_bus = parent_bus;
132
133 ret_val = -ENODEV;
134 for_each_available_child_of_node(dev->of_node, child_bus_node) {
135 u32 v;
136
137 r = of_property_read_u32(child_bus_node, "reg", &v);
138 if (r)
139 continue;
140
141 cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
142 if (cb == NULL) {
143 dev_err(dev,
144 "Error: Failed to allocate memory for child\n");
145 ret_val = -ENOMEM;
146 of_node_put(child_bus_node);
147 break;
148 }
149 cb->bus_number = v;
150 cb->parent = pb;
151
152 cb->mii_bus = mdiobus_alloc();
153 if (!cb->mii_bus) {
154 ret_val = -ENOMEM;
155 of_node_put(child_bus_node);
156 break;
157 }
158 cb->mii_bus->priv = cb;
159
160 cb->mii_bus->name = "mdio_mux";
161 snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%x.%x",
162 pb->parent_id, v);
163 cb->mii_bus->parent = dev;
164 cb->mii_bus->read = mdio_mux_read;
165 cb->mii_bus->write = mdio_mux_write;
166 r = of_mdiobus_register(cb->mii_bus, child_bus_node);
167 if (r) {
168 mdiobus_free(cb->mii_bus);
169 devm_kfree(dev, cb);
170 } else {
171 of_node_get(child_bus_node);
172 cb->next = pb->children;
173 pb->children = cb;
174 }
175 }
176 if (pb->children) {
177 *mux_handle = pb;
178 dev_info(dev, "Version " DRV_VERSION "\n");
179 return 0;
180 }
181
182 /* balance the reference of_mdio_find_bus() took */
183 put_device(&pb->mii_bus->dev);
184
185err_parent_bus:
186 of_node_put(parent_bus_node);
187 return ret_val;
188}
189EXPORT_SYMBOL_GPL(mdio_mux_init);
190
191void mdio_mux_uninit(void *mux_handle)
192{
193 struct mdio_mux_parent_bus *pb = mux_handle;
194 struct mdio_mux_child_bus *cb = pb->children;
195
196 while (cb) {
197 mdiobus_unregister(cb->mii_bus);
198 mdiobus_free(cb->mii_bus);
199 cb = cb->next;
200 }
201
202 /* balance the reference of_mdio_find_bus() in mdio_mux_init() took */
203 put_device(&pb->mii_bus->dev);
204}
205EXPORT_SYMBOL_GPL(mdio_mux_uninit);
206
207MODULE_DESCRIPTION(DRV_DESCRIPTION);
208MODULE_VERSION(DRV_VERSION);
209MODULE_AUTHOR("David Daney");
210MODULE_LICENSE("GPL");