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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2011, 2012 Cavium, Inc.
4 */
5
6#include <linux/platform_device.h>
7#include <linux/mdio-mux.h>
8#include <linux/of_mdio.h>
9#include <linux/device.h>
10#include <linux/module.h>
11#include <linux/phy.h>
12
13#define DRV_DESCRIPTION "MDIO bus multiplexer driver"
14
15struct mdio_mux_child_bus;
16
17struct mdio_mux_parent_bus {
18 struct mii_bus *mii_bus;
19 int current_child;
20 int parent_id;
21 void *switch_data;
22 int (*switch_fn)(int current_child, int desired_child, void *data);
23
24 /* List of our children linked through their next fields. */
25 struct mdio_mux_child_bus *children;
26};
27
28struct mdio_mux_child_bus {
29 struct mii_bus *mii_bus;
30 struct mdio_mux_parent_bus *parent;
31 struct mdio_mux_child_bus *next;
32 int bus_number;
33};
34
35/*
36 * The parent bus' lock is used to order access to the switch_fn.
37 */
38static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum)
39{
40 struct mdio_mux_child_bus *cb = bus->priv;
41 struct mdio_mux_parent_bus *pb = cb->parent;
42 int r;
43
44 mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
45 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
46 if (r)
47 goto out;
48
49 pb->current_child = cb->bus_number;
50
51 r = pb->mii_bus->read(pb->mii_bus, phy_id, regnum);
52out:
53 mutex_unlock(&pb->mii_bus->mdio_lock);
54
55 return r;
56}
57
58/*
59 * The parent bus' lock is used to order access to the switch_fn.
60 */
61static int mdio_mux_write(struct mii_bus *bus, int phy_id,
62 int regnum, u16 val)
63{
64 struct mdio_mux_child_bus *cb = bus->priv;
65 struct mdio_mux_parent_bus *pb = cb->parent;
66
67 int r;
68
69 mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
70 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
71 if (r)
72 goto out;
73
74 pb->current_child = cb->bus_number;
75
76 r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val);
77out:
78 mutex_unlock(&pb->mii_bus->mdio_lock);
79
80 return r;
81}
82
83static int parent_count;
84
85int mdio_mux_init(struct device *dev,
86 struct device_node *mux_node,
87 int (*switch_fn)(int cur, int desired, void *data),
88 void **mux_handle,
89 void *data,
90 struct mii_bus *mux_bus)
91{
92 struct device_node *parent_bus_node;
93 struct device_node *child_bus_node;
94 int r, ret_val;
95 struct mii_bus *parent_bus;
96 struct mdio_mux_parent_bus *pb;
97 struct mdio_mux_child_bus *cb;
98
99 if (!mux_node)
100 return -ENODEV;
101
102 if (!mux_bus) {
103 parent_bus_node = of_parse_phandle(mux_node,
104 "mdio-parent-bus", 0);
105
106 if (!parent_bus_node)
107 return -ENODEV;
108
109 parent_bus = of_mdio_find_bus(parent_bus_node);
110 if (!parent_bus) {
111 ret_val = -EPROBE_DEFER;
112 goto err_parent_bus;
113 }
114 } else {
115 parent_bus_node = NULL;
116 parent_bus = mux_bus;
117 get_device(&parent_bus->dev);
118 }
119
120 pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
121 if (!pb) {
122 ret_val = -ENOMEM;
123 goto err_pb_kz;
124 }
125
126 pb->switch_data = data;
127 pb->switch_fn = switch_fn;
128 pb->current_child = -1;
129 pb->parent_id = parent_count++;
130 pb->mii_bus = parent_bus;
131
132 ret_val = -ENODEV;
133 for_each_available_child_of_node(mux_node, child_bus_node) {
134 int v;
135
136 r = of_property_read_u32(child_bus_node, "reg", &v);
137 if (r) {
138 dev_err(dev,
139 "Error: Failed to find reg for child %pOF\n",
140 child_bus_node);
141 continue;
142 }
143
144 cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
145 if (!cb) {
146 ret_val = -ENOMEM;
147 continue;
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 devm_kfree(dev, cb);
156 continue;
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 dev_err(dev,
169 "Error: Failed to register MDIO bus for child %pOF\n",
170 child_bus_node);
171 mdiobus_free(cb->mii_bus);
172 devm_kfree(dev, cb);
173 } else {
174 cb->next = pb->children;
175 pb->children = cb;
176 }
177 }
178 if (pb->children) {
179 *mux_handle = pb;
180 return 0;
181 }
182
183 dev_err(dev, "Error: No acceptable child buses found\n");
184 devm_kfree(dev, pb);
185err_pb_kz:
186 put_device(&parent_bus->dev);
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 put_device(&pb->mii_bus->dev);
205}
206EXPORT_SYMBOL_GPL(mdio_mux_uninit);
207
208MODULE_DESCRIPTION(DRV_DESCRIPTION);
209MODULE_AUTHOR("David Daney");
210MODULE_LICENSE("GPL v2");
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");