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0ca2997d DD |
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 | ||
19 | struct mdio_mux_child_bus; | |
20 | ||
21 | struct 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 | ||
32 | struct 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; | |
0ca2997d DD |
37 | }; |
38 | ||
39 | /* | |
40 | * The parent bus' lock is used to order access to the switch_fn. | |
41 | */ | |
42 | static 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 | ||
9a6f2b01 | 48 | mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX); |
0ca2997d DD |
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); | |
56 | out: | |
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 | */ | |
65 | static 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 | ||
9a6f2b01 | 73 | mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX); |
0ca2997d DD |
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); | |
81 | out: | |
82 | mutex_unlock(&pb->mii_bus->mdio_lock); | |
83 | ||
84 | return r; | |
85 | } | |
86 | ||
87 | static int parent_count; | |
88 | ||
89 | int mdio_mux_init(struct device *dev, | |
90 | int (*switch_fn)(int cur, int desired, void *data), | |
91 | void **mux_handle, | |
f20e6657 PK |
92 | void *data, |
93 | struct mii_bus *mux_bus) | |
0ca2997d DD |
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 | ||
f20e6657 PK |
105 | if (!mux_bus) { |
106 | parent_bus_node = of_parse_phandle(dev->of_node, | |
107 | "mdio-parent-bus", 0); | |
0ca2997d | 108 | |
f20e6657 PK |
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 { | |
a78c16e1 | 118 | parent_bus_node = NULL; |
f20e6657 PK |
119 | parent_bus = mux_bus; |
120 | } | |
0ca2997d | 121 | |
0ca2997d DD |
122 | pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL); |
123 | if (pb == NULL) { | |
124 | ret_val = -ENOMEM; | |
125 | goto err_parent_bus; | |
126 | } | |
127 | ||
a1364421 | 128 | |
0ca2997d DD |
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; | |
61abcb7b | 136 | for_each_available_child_of_node(dev->of_node, child_bus_node) { |
0ca2997d DD |
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; | |
447ed736 | 148 | of_node_put(child_bus_node); |
0ca2997d DD |
149 | break; |
150 | } | |
151 | cb->bus_number = v; | |
152 | cb->parent = pb; | |
20b08e1a | 153 | |
0ca2997d | 154 | cb->mii_bus = mdiobus_alloc(); |
20b08e1a TK |
155 | if (!cb->mii_bus) { |
156 | ret_val = -ENOMEM; | |
157 | of_node_put(child_bus_node); | |
158 | break; | |
159 | } | |
0ca2997d | 160 | cb->mii_bus->priv = cb; |
e7f4dc35 | 161 | |
0ca2997d DD |
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 | } | |
a1364421 RK |
183 | |
184 | /* balance the reference of_mdio_find_bus() took */ | |
185 | put_device(&pb->mii_bus->dev); | |
186 | ||
0ca2997d | 187 | err_parent_bus: |
a78c16e1 | 188 | of_node_put(parent_bus_node); |
0ca2997d DD |
189 | return ret_val; |
190 | } | |
191 | EXPORT_SYMBOL_GPL(mdio_mux_init); | |
192 | ||
193 | void 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 | } | |
a1364421 RK |
203 | |
204 | /* balance the reference of_mdio_find_bus() in mdio_mux_init() took */ | |
205 | put_device(&pb->mii_bus->dev); | |
0ca2997d DD |
206 | } |
207 | EXPORT_SYMBOL_GPL(mdio_mux_uninit); | |
208 | ||
209 | MODULE_DESCRIPTION(DRV_DESCRIPTION); | |
210 | MODULE_VERSION(DRV_VERSION); | |
211 | MODULE_AUTHOR("David Daney"); | |
212 | MODULE_LICENSE("GPL"); |