1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2011, 2012 Cavium, Inc. 4 */ 5 6 #include <linux/device.h> 7 #include <linux/mdio-mux.h> 8 #include <linux/module.h> 9 #include <linux/of_mdio.h> 10 #include <linux/phy.h> 11 #include <linux/platform_device.h> 12 13 #define DRV_DESCRIPTION "MDIO bus multiplexer driver" 14 15 struct mdio_mux_child_bus; 16 17 struct 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 28 struct 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 */ 38 static 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); 52 out: 53 mutex_unlock(&pb->mii_bus->mdio_lock); 54 55 return r; 56 } 57 58 static int mdio_mux_read_c45(struct mii_bus *bus, int phy_id, int dev_addr, 59 int regnum) 60 { 61 struct mdio_mux_child_bus *cb = bus->priv; 62 struct mdio_mux_parent_bus *pb = cb->parent; 63 int r; 64 65 mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX); 66 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data); 67 if (r) 68 goto out; 69 70 pb->current_child = cb->bus_number; 71 72 r = pb->mii_bus->read_c45(pb->mii_bus, phy_id, dev_addr, regnum); 73 out: 74 mutex_unlock(&pb->mii_bus->mdio_lock); 75 76 return r; 77 } 78 79 /* 80 * The parent bus' lock is used to order access to the switch_fn. 81 */ 82 static int mdio_mux_write(struct mii_bus *bus, int phy_id, 83 int regnum, u16 val) 84 { 85 struct mdio_mux_child_bus *cb = bus->priv; 86 struct mdio_mux_parent_bus *pb = cb->parent; 87 88 int r; 89 90 mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX); 91 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data); 92 if (r) 93 goto out; 94 95 pb->current_child = cb->bus_number; 96 97 r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val); 98 out: 99 mutex_unlock(&pb->mii_bus->mdio_lock); 100 101 return r; 102 } 103 104 static int mdio_mux_write_c45(struct mii_bus *bus, int phy_id, int dev_addr, 105 int regnum, u16 val) 106 { 107 struct mdio_mux_child_bus *cb = bus->priv; 108 struct mdio_mux_parent_bus *pb = cb->parent; 109 110 int r; 111 112 mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX); 113 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data); 114 if (r) 115 goto out; 116 117 pb->current_child = cb->bus_number; 118 119 r = pb->mii_bus->write_c45(pb->mii_bus, phy_id, dev_addr, regnum, val); 120 out: 121 mutex_unlock(&pb->mii_bus->mdio_lock); 122 123 return r; 124 } 125 126 static int parent_count; 127 128 static void mdio_mux_uninit_children(struct mdio_mux_parent_bus *pb) 129 { 130 struct mdio_mux_child_bus *cb = pb->children; 131 132 while (cb) { 133 mdiobus_unregister(cb->mii_bus); 134 mdiobus_free(cb->mii_bus); 135 cb = cb->next; 136 } 137 } 138 139 int mdio_mux_init(struct device *dev, 140 struct device_node *mux_node, 141 int (*switch_fn)(int cur, int desired, void *data), 142 void **mux_handle, 143 void *data, 144 struct mii_bus *mux_bus) 145 { 146 struct device_node *parent_bus_node; 147 struct device_node *child_bus_node; 148 int r, ret_val; 149 struct mii_bus *parent_bus; 150 struct mdio_mux_parent_bus *pb; 151 struct mdio_mux_child_bus *cb; 152 153 if (!mux_node) 154 return -ENODEV; 155 156 if (!mux_bus) { 157 parent_bus_node = of_parse_phandle(mux_node, 158 "mdio-parent-bus", 0); 159 160 if (!parent_bus_node) 161 return -ENODEV; 162 163 parent_bus = of_mdio_find_bus(parent_bus_node); 164 if (!parent_bus) { 165 ret_val = -EPROBE_DEFER; 166 goto err_parent_bus; 167 } 168 } else { 169 parent_bus_node = NULL; 170 parent_bus = mux_bus; 171 get_device(&parent_bus->dev); 172 } 173 174 pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL); 175 if (!pb) { 176 ret_val = -ENOMEM; 177 goto err_pb_kz; 178 } 179 180 pb->switch_data = data; 181 pb->switch_fn = switch_fn; 182 pb->current_child = -1; 183 pb->parent_id = parent_count++; 184 pb->mii_bus = parent_bus; 185 186 ret_val = -ENODEV; 187 for_each_available_child_of_node(mux_node, child_bus_node) { 188 int v; 189 190 r = of_property_read_u32(child_bus_node, "reg", &v); 191 if (r) { 192 dev_err(dev, 193 "Error: Failed to find reg for child %pOF\n", 194 child_bus_node); 195 continue; 196 } 197 198 cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL); 199 if (!cb) { 200 ret_val = -ENOMEM; 201 goto err_loop; 202 } 203 cb->bus_number = v; 204 cb->parent = pb; 205 206 cb->mii_bus = mdiobus_alloc(); 207 if (!cb->mii_bus) { 208 ret_val = -ENOMEM; 209 goto err_loop; 210 } 211 cb->mii_bus->priv = cb; 212 213 cb->mii_bus->name = "mdio_mux"; 214 snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%s-%x.%x", 215 cb->mii_bus->name, pb->parent_id, v); 216 cb->mii_bus->parent = dev; 217 cb->mii_bus->read = mdio_mux_read; 218 cb->mii_bus->write = mdio_mux_write; 219 if (parent_bus->read_c45) 220 cb->mii_bus->read_c45 = mdio_mux_read_c45; 221 if (parent_bus->write_c45) 222 cb->mii_bus->write_c45 = mdio_mux_write_c45; 223 r = of_mdiobus_register(cb->mii_bus, child_bus_node); 224 if (r) { 225 mdiobus_free(cb->mii_bus); 226 if (r == -EPROBE_DEFER) { 227 ret_val = r; 228 goto err_loop; 229 } 230 devm_kfree(dev, cb); 231 dev_err(dev, 232 "Error: Failed to register MDIO bus for child %pOF\n", 233 child_bus_node); 234 } else { 235 cb->next = pb->children; 236 pb->children = cb; 237 } 238 } 239 if (pb->children) { 240 *mux_handle = pb; 241 return 0; 242 } 243 244 dev_err(dev, "Error: No acceptable child buses found\n"); 245 246 err_loop: 247 mdio_mux_uninit_children(pb); 248 of_node_put(child_bus_node); 249 err_pb_kz: 250 put_device(&parent_bus->dev); 251 err_parent_bus: 252 of_node_put(parent_bus_node); 253 return ret_val; 254 } 255 EXPORT_SYMBOL_GPL(mdio_mux_init); 256 257 void mdio_mux_uninit(void *mux_handle) 258 { 259 struct mdio_mux_parent_bus *pb = mux_handle; 260 261 mdio_mux_uninit_children(pb); 262 put_device(&pb->mii_bus->dev); 263 } 264 EXPORT_SYMBOL_GPL(mdio_mux_uninit); 265 266 MODULE_DESCRIPTION(DRV_DESCRIPTION); 267 MODULE_AUTHOR("David Daney"); 268 MODULE_LICENSE("GPL v2"); 269