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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 | ||
b93984c9 DD |
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); | |
0ca2997d DD |
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); | |
62 | out: | |
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 | */ | |
71 | static 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 | ||
b93984c9 | 79 | mutex_lock_nested(&pb->mii_bus->mdio_lock, SINGLE_DEPTH_NESTING); |
0ca2997d DD |
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); | |
87 | out: | |
88 | mutex_unlock(&pb->mii_bus->mdio_lock); | |
89 | ||
90 | return r; | |
91 | } | |
92 | ||
93 | static int parent_count; | |
94 | ||
95 | int 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 | ||
0ca2997d DD |
115 | pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL); |
116 | if (pb == NULL) { | |
117 | ret_val = -ENOMEM; | |
118 | goto err_parent_bus; | |
119 | } | |
120 | ||
a1364421 RK |
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 | ||
0ca2997d DD |
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; | |
61abcb7b | 134 | for_each_available_child_of_node(dev->of_node, child_bus_node) { |
0ca2997d DD |
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; | |
447ed736 | 146 | of_node_put(child_bus_node); |
0ca2997d DD |
147 | break; |
148 | } | |
149 | cb->bus_number = v; | |
150 | cb->parent = pb; | |
20b08e1a | 151 | |
0ca2997d | 152 | cb->mii_bus = mdiobus_alloc(); |
20b08e1a TK |
153 | if (!cb->mii_bus) { |
154 | ret_val = -ENOMEM; | |
155 | of_node_put(child_bus_node); | |
156 | break; | |
157 | } | |
0ca2997d | 158 | cb->mii_bus->priv = cb; |
e7f4dc35 | 159 | |
0ca2997d DD |
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 | } | |
a1364421 RK |
181 | |
182 | /* balance the reference of_mdio_find_bus() took */ | |
183 | put_device(&pb->mii_bus->dev); | |
184 | ||
0ca2997d DD |
185 | err_parent_bus: |
186 | of_node_put(parent_bus_node); | |
187 | return ret_val; | |
188 | } | |
189 | EXPORT_SYMBOL_GPL(mdio_mux_init); | |
190 | ||
191 | void 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 | } | |
a1364421 RK |
201 | |
202 | /* balance the reference of_mdio_find_bus() in mdio_mux_init() took */ | |
203 | put_device(&pb->mii_bus->dev); | |
0ca2997d DD |
204 | } |
205 | EXPORT_SYMBOL_GPL(mdio_mux_uninit); | |
206 | ||
207 | MODULE_DESCRIPTION(DRV_DESCRIPTION); | |
208 | MODULE_VERSION(DRV_VERSION); | |
209 | MODULE_AUTHOR("David Daney"); | |
210 | MODULE_LICENSE("GPL"); |