linux/drivers/net/phy/mdio_bus.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/* MDIO Bus interface
   3 *
   4 * Author: Andy Fleming
   5 *
   6 * Copyright (c) 2004 Freescale Semiconductor, Inc.
   7 */
   8
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/delay.h>
  12#include <linux/device.h>
  13#include <linux/errno.h>
  14#include <linux/etherdevice.h>
  15#include <linux/ethtool.h>
  16#include <linux/gpio.h>
  17#include <linux/gpio/consumer.h>
  18#include <linux/init.h>
  19#include <linux/interrupt.h>
  20#include <linux/io.h>
  21#include <linux/kernel.h>
  22#include <linux/mii.h>
  23#include <linux/mm.h>
  24#include <linux/module.h>
  25#include <linux/netdevice.h>
  26#include <linux/of_device.h>
  27#include <linux/of_gpio.h>
  28#include <linux/of_mdio.h>
  29#include <linux/phy.h>
  30#include <linux/reset.h>
  31#include <linux/skbuff.h>
  32#include <linux/slab.h>
  33#include <linux/spinlock.h>
  34#include <linux/string.h>
  35#include <linux/uaccess.h>
  36#include <linux/unistd.h>
  37
  38#define CREATE_TRACE_POINTS
  39#include <trace/events/mdio.h>
  40
  41#include "mdio-boardinfo.h"
  42
  43static int mdiobus_register_gpiod(struct mdio_device *mdiodev)
  44{
  45        /* Deassert the optional reset signal */
  46        mdiodev->reset_gpio = gpiod_get_optional(&mdiodev->dev,
  47                                                 "reset", GPIOD_OUT_LOW);
  48        if (IS_ERR(mdiodev->reset_gpio))
  49                return PTR_ERR(mdiodev->reset_gpio);
  50
  51        if (mdiodev->reset_gpio)
  52                gpiod_set_consumer_name(mdiodev->reset_gpio, "PHY reset");
  53
  54        return 0;
  55}
  56
  57static int mdiobus_register_reset(struct mdio_device *mdiodev)
  58{
  59        struct reset_control *reset;
  60
  61        reset = reset_control_get_optional_exclusive(&mdiodev->dev, "phy");
  62        if (IS_ERR(reset))
  63                return PTR_ERR(reset);
  64
  65        mdiodev->reset_ctrl = reset;
  66
  67        return 0;
  68}
  69
  70int mdiobus_register_device(struct mdio_device *mdiodev)
  71{
  72        int err;
  73
  74        if (mdiodev->bus->mdio_map[mdiodev->addr])
  75                return -EBUSY;
  76
  77        if (mdiodev->flags & MDIO_DEVICE_FLAG_PHY) {
  78                err = mdiobus_register_gpiod(mdiodev);
  79                if (err)
  80                        return err;
  81
  82                err = mdiobus_register_reset(mdiodev);
  83                if (err)
  84                        return err;
  85
  86                /* Assert the reset signal */
  87                mdio_device_reset(mdiodev, 1);
  88        }
  89
  90        mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
  91
  92        return 0;
  93}
  94EXPORT_SYMBOL(mdiobus_register_device);
  95
  96int mdiobus_unregister_device(struct mdio_device *mdiodev)
  97{
  98        if (mdiodev->bus->mdio_map[mdiodev->addr] != mdiodev)
  99                return -EINVAL;
 100
 101        reset_control_put(mdiodev->reset_ctrl);
 102
 103        mdiodev->bus->mdio_map[mdiodev->addr] = NULL;
 104
 105        return 0;
 106}
 107EXPORT_SYMBOL(mdiobus_unregister_device);
 108
 109struct phy_device *mdiobus_get_phy(struct mii_bus *bus, int addr)
 110{
 111        struct mdio_device *mdiodev = bus->mdio_map[addr];
 112
 113        if (!mdiodev)
 114                return NULL;
 115
 116        if (!(mdiodev->flags & MDIO_DEVICE_FLAG_PHY))
 117                return NULL;
 118
 119        return container_of(mdiodev, struct phy_device, mdio);
 120}
 121EXPORT_SYMBOL(mdiobus_get_phy);
 122
 123bool mdiobus_is_registered_device(struct mii_bus *bus, int addr)
 124{
 125        return bus->mdio_map[addr];
 126}
 127EXPORT_SYMBOL(mdiobus_is_registered_device);
 128
 129/**
 130 * mdiobus_alloc_size - allocate a mii_bus structure
 131 * @size: extra amount of memory to allocate for private storage.
 132 * If non-zero, then bus->priv is points to that memory.
 133 *
 134 * Description: called by a bus driver to allocate an mii_bus
 135 * structure to fill in.
 136 */
 137struct mii_bus *mdiobus_alloc_size(size_t size)
 138{
 139        struct mii_bus *bus;
 140        size_t aligned_size = ALIGN(sizeof(*bus), NETDEV_ALIGN);
 141        size_t alloc_size;
 142        int i;
 143
 144        /* If we alloc extra space, it should be aligned */
 145        if (size)
 146                alloc_size = aligned_size + size;
 147        else
 148                alloc_size = sizeof(*bus);
 149
 150        bus = kzalloc(alloc_size, GFP_KERNEL);
 151        if (!bus)
 152                return NULL;
 153
 154        bus->state = MDIOBUS_ALLOCATED;
 155        if (size)
 156                bus->priv = (void *)bus + aligned_size;
 157
 158        /* Initialise the interrupts to polling and 64-bit seqcounts */
 159        for (i = 0; i < PHY_MAX_ADDR; i++) {
 160                bus->irq[i] = PHY_POLL;
 161                u64_stats_init(&bus->stats[i].syncp);
 162        }
 163
 164        return bus;
 165}
 166EXPORT_SYMBOL(mdiobus_alloc_size);
 167
 168/**
 169 * mdiobus_release - mii_bus device release callback
 170 * @d: the target struct device that contains the mii_bus
 171 *
 172 * Description: called when the last reference to an mii_bus is
 173 * dropped, to free the underlying memory.
 174 */
 175static void mdiobus_release(struct device *d)
 176{
 177        struct mii_bus *bus = to_mii_bus(d);
 178        BUG_ON(bus->state != MDIOBUS_RELEASED &&
 179               /* for compatibility with error handling in drivers */
 180               bus->state != MDIOBUS_ALLOCATED);
 181        kfree(bus);
 182}
 183
 184struct mdio_bus_stat_attr {
 185        int addr;
 186        unsigned int field_offset;
 187};
 188
 189static u64 mdio_bus_get_stat(struct mdio_bus_stats *s, unsigned int offset)
 190{
 191        const char *p = (const char *)s + offset;
 192        unsigned int start;
 193        u64 val = 0;
 194
 195        do {
 196                start = u64_stats_fetch_begin(&s->syncp);
 197                val = u64_stats_read((const u64_stats_t *)p);
 198        } while (u64_stats_fetch_retry(&s->syncp, start));
 199
 200        return val;
 201}
 202
 203static u64 mdio_bus_get_global_stat(struct mii_bus *bus, unsigned int offset)
 204{
 205        unsigned int i;
 206        u64 val = 0;
 207
 208        for (i = 0; i < PHY_MAX_ADDR; i++)
 209                val += mdio_bus_get_stat(&bus->stats[i], offset);
 210
 211        return val;
 212}
 213
 214static ssize_t mdio_bus_stat_field_show(struct device *dev,
 215                                        struct device_attribute *attr,
 216                                        char *buf)
 217{
 218        struct mii_bus *bus = to_mii_bus(dev);
 219        struct mdio_bus_stat_attr *sattr;
 220        struct dev_ext_attribute *eattr;
 221        u64 val;
 222
 223        eattr = container_of(attr, struct dev_ext_attribute, attr);
 224        sattr = eattr->var;
 225
 226        if (sattr->addr < 0)
 227                val = mdio_bus_get_global_stat(bus, sattr->field_offset);
 228        else
 229                val = mdio_bus_get_stat(&bus->stats[sattr->addr],
 230                                        sattr->field_offset);
 231
 232        return sprintf(buf, "%llu\n", val);
 233}
 234
 235static ssize_t mdio_bus_device_stat_field_show(struct device *dev,
 236                                               struct device_attribute *attr,
 237                                               char *buf)
 238{
 239        struct mdio_device *mdiodev = to_mdio_device(dev);
 240        struct mii_bus *bus = mdiodev->bus;
 241        struct mdio_bus_stat_attr *sattr;
 242        struct dev_ext_attribute *eattr;
 243        int addr = mdiodev->addr;
 244        u64 val;
 245
 246        eattr = container_of(attr, struct dev_ext_attribute, attr);
 247        sattr = eattr->var;
 248
 249        val = mdio_bus_get_stat(&bus->stats[addr], sattr->field_offset);
 250
 251        return sprintf(buf, "%llu\n", val);
 252}
 253
 254#define MDIO_BUS_STATS_ATTR_DECL(field, file)                           \
 255static struct dev_ext_attribute dev_attr_mdio_bus_##field = {           \
 256        .attr = { .attr = { .name = file, .mode = 0444 },               \
 257                     .show = mdio_bus_stat_field_show,                  \
 258        },                                                              \
 259        .var = &((struct mdio_bus_stat_attr) {                          \
 260                -1, offsetof(struct mdio_bus_stats, field)              \
 261        }),                                                             \
 262};                                                                      \
 263static struct dev_ext_attribute dev_attr_mdio_bus_device_##field = {    \
 264        .attr = { .attr = { .name = file, .mode = 0444 },               \
 265                     .show = mdio_bus_device_stat_field_show,           \
 266        },                                                              \
 267        .var = &((struct mdio_bus_stat_attr) {                          \
 268                -1, offsetof(struct mdio_bus_stats, field)              \
 269        }),                                                             \
 270};
 271
 272#define MDIO_BUS_STATS_ATTR(field)                                      \
 273        MDIO_BUS_STATS_ATTR_DECL(field, __stringify(field))
 274
 275MDIO_BUS_STATS_ATTR(transfers);
 276MDIO_BUS_STATS_ATTR(errors);
 277MDIO_BUS_STATS_ATTR(writes);
 278MDIO_BUS_STATS_ATTR(reads);
 279
 280#define MDIO_BUS_STATS_ADDR_ATTR_DECL(field, addr, file)                \
 281static struct dev_ext_attribute dev_attr_mdio_bus_addr_##field##_##addr = { \
 282        .attr = { .attr = { .name = file, .mode = 0444 },               \
 283                     .show = mdio_bus_stat_field_show,                  \
 284        },                                                              \
 285        .var = &((struct mdio_bus_stat_attr) {                          \
 286                addr, offsetof(struct mdio_bus_stats, field)            \
 287        }),                                                             \
 288}
 289
 290#define MDIO_BUS_STATS_ADDR_ATTR(field, addr)                           \
 291        MDIO_BUS_STATS_ADDR_ATTR_DECL(field, addr,                      \
 292                                 __stringify(field) "_" __stringify(addr))
 293
 294#define MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(addr)                       \
 295        MDIO_BUS_STATS_ADDR_ATTR(transfers, addr);                      \
 296        MDIO_BUS_STATS_ADDR_ATTR(errors, addr);                         \
 297        MDIO_BUS_STATS_ADDR_ATTR(writes, addr);                         \
 298        MDIO_BUS_STATS_ADDR_ATTR(reads, addr)                           \
 299
 300MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(0);
 301MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(1);
 302MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(2);
 303MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(3);
 304MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(4);
 305MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(5);
 306MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(6);
 307MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(7);
 308MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(8);
 309MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(9);
 310MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(10);
 311MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(11);
 312MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(12);
 313MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(13);
 314MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(14);
 315MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(15);
 316MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(16);
 317MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(17);
 318MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(18);
 319MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(19);
 320MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(20);
 321MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(21);
 322MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(22);
 323MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(23);
 324MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(24);
 325MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(25);
 326MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(26);
 327MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(27);
 328MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(28);
 329MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(29);
 330MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(30);
 331MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(31);
 332
 333#define MDIO_BUS_STATS_ADDR_ATTR_GROUP(addr)                            \
 334        &dev_attr_mdio_bus_addr_transfers_##addr.attr.attr,             \
 335        &dev_attr_mdio_bus_addr_errors_##addr.attr.attr,                \
 336        &dev_attr_mdio_bus_addr_writes_##addr.attr.attr,                \
 337        &dev_attr_mdio_bus_addr_reads_##addr.attr.attr                  \
 338
 339static struct attribute *mdio_bus_statistics_attrs[] = {
 340        &dev_attr_mdio_bus_transfers.attr.attr,
 341        &dev_attr_mdio_bus_errors.attr.attr,
 342        &dev_attr_mdio_bus_writes.attr.attr,
 343        &dev_attr_mdio_bus_reads.attr.attr,
 344        MDIO_BUS_STATS_ADDR_ATTR_GROUP(0),
 345        MDIO_BUS_STATS_ADDR_ATTR_GROUP(1),
 346        MDIO_BUS_STATS_ADDR_ATTR_GROUP(2),
 347        MDIO_BUS_STATS_ADDR_ATTR_GROUP(3),
 348        MDIO_BUS_STATS_ADDR_ATTR_GROUP(4),
 349        MDIO_BUS_STATS_ADDR_ATTR_GROUP(5),
 350        MDIO_BUS_STATS_ADDR_ATTR_GROUP(6),
 351        MDIO_BUS_STATS_ADDR_ATTR_GROUP(7),
 352        MDIO_BUS_STATS_ADDR_ATTR_GROUP(8),
 353        MDIO_BUS_STATS_ADDR_ATTR_GROUP(9),
 354        MDIO_BUS_STATS_ADDR_ATTR_GROUP(10),
 355        MDIO_BUS_STATS_ADDR_ATTR_GROUP(11),
 356        MDIO_BUS_STATS_ADDR_ATTR_GROUP(12),
 357        MDIO_BUS_STATS_ADDR_ATTR_GROUP(13),
 358        MDIO_BUS_STATS_ADDR_ATTR_GROUP(14),
 359        MDIO_BUS_STATS_ADDR_ATTR_GROUP(15),
 360        MDIO_BUS_STATS_ADDR_ATTR_GROUP(16),
 361        MDIO_BUS_STATS_ADDR_ATTR_GROUP(17),
 362        MDIO_BUS_STATS_ADDR_ATTR_GROUP(18),
 363        MDIO_BUS_STATS_ADDR_ATTR_GROUP(19),
 364        MDIO_BUS_STATS_ADDR_ATTR_GROUP(20),
 365        MDIO_BUS_STATS_ADDR_ATTR_GROUP(21),
 366        MDIO_BUS_STATS_ADDR_ATTR_GROUP(22),
 367        MDIO_BUS_STATS_ADDR_ATTR_GROUP(23),
 368        MDIO_BUS_STATS_ADDR_ATTR_GROUP(24),
 369        MDIO_BUS_STATS_ADDR_ATTR_GROUP(25),
 370        MDIO_BUS_STATS_ADDR_ATTR_GROUP(26),
 371        MDIO_BUS_STATS_ADDR_ATTR_GROUP(27),
 372        MDIO_BUS_STATS_ADDR_ATTR_GROUP(28),
 373        MDIO_BUS_STATS_ADDR_ATTR_GROUP(29),
 374        MDIO_BUS_STATS_ADDR_ATTR_GROUP(30),
 375        MDIO_BUS_STATS_ADDR_ATTR_GROUP(31),
 376        NULL,
 377};
 378
 379static const struct attribute_group mdio_bus_statistics_group = {
 380        .name   = "statistics",
 381        .attrs  = mdio_bus_statistics_attrs,
 382};
 383
 384static const struct attribute_group *mdio_bus_groups[] = {
 385        &mdio_bus_statistics_group,
 386        NULL,
 387};
 388
 389static struct class mdio_bus_class = {
 390        .name           = "mdio_bus",
 391        .dev_release    = mdiobus_release,
 392        .dev_groups     = mdio_bus_groups,
 393};
 394
 395/**
 396 * mdio_find_bus - Given the name of a mdiobus, find the mii_bus.
 397 * @mdio_name: The name of a mdiobus.
 398 *
 399 * Returns a reference to the mii_bus, or NULL if none found.  The
 400 * embedded struct device will have its reference count incremented,
 401 * and this must be put_deviced'ed once the bus is finished with.
 402 */
 403struct mii_bus *mdio_find_bus(const char *mdio_name)
 404{
 405        struct device *d;
 406
 407        d = class_find_device_by_name(&mdio_bus_class, mdio_name);
 408        return d ? to_mii_bus(d) : NULL;
 409}
 410EXPORT_SYMBOL(mdio_find_bus);
 411
 412#if IS_ENABLED(CONFIG_OF_MDIO)
 413/**
 414 * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
 415 * @mdio_bus_np: Pointer to the mii_bus.
 416 *
 417 * Returns a reference to the mii_bus, or NULL if none found.  The
 418 * embedded struct device will have its reference count incremented,
 419 * and this must be put once the bus is finished with.
 420 *
 421 * Because the association of a device_node and mii_bus is made via
 422 * of_mdiobus_register(), the mii_bus cannot be found before it is
 423 * registered with of_mdiobus_register().
 424 *
 425 */
 426struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
 427{
 428        struct device *d;
 429
 430        if (!mdio_bus_np)
 431                return NULL;
 432
 433        d = class_find_device_by_of_node(&mdio_bus_class, mdio_bus_np);
 434        return d ? to_mii_bus(d) : NULL;
 435}
 436EXPORT_SYMBOL(of_mdio_find_bus);
 437
 438/* Walk the list of subnodes of a mdio bus and look for a node that
 439 * matches the mdio device's address with its 'reg' property. If
 440 * found, set the of_node pointer for the mdio device. This allows
 441 * auto-probed phy devices to be supplied with information passed in
 442 * via DT.
 443 */
 444static void of_mdiobus_link_mdiodev(struct mii_bus *bus,
 445                                    struct mdio_device *mdiodev)
 446{
 447        struct device *dev = &mdiodev->dev;
 448        struct device_node *child;
 449
 450        if (dev->of_node || !bus->dev.of_node)
 451                return;
 452
 453        for_each_available_child_of_node(bus->dev.of_node, child) {
 454                int addr;
 455
 456                addr = of_mdio_parse_addr(dev, child);
 457                if (addr < 0)
 458                        continue;
 459
 460                if (addr == mdiodev->addr) {
 461                        dev->of_node = child;
 462                        dev->fwnode = of_fwnode_handle(child);
 463                        return;
 464                }
 465        }
 466}
 467#else /* !IS_ENABLED(CONFIG_OF_MDIO) */
 468static inline void of_mdiobus_link_mdiodev(struct mii_bus *mdio,
 469                                           struct mdio_device *mdiodev)
 470{
 471}
 472#endif
 473
 474/**
 475 * mdiobus_create_device_from_board_info - create a full MDIO device given
 476 * a mdio_board_info structure
 477 * @bus: MDIO bus to create the devices on
 478 * @bi: mdio_board_info structure describing the devices
 479 *
 480 * Returns 0 on success or < 0 on error.
 481 */
 482static int mdiobus_create_device(struct mii_bus *bus,
 483                                 struct mdio_board_info *bi)
 484{
 485        struct mdio_device *mdiodev;
 486        int ret = 0;
 487
 488        mdiodev = mdio_device_create(bus, bi->mdio_addr);
 489        if (IS_ERR(mdiodev))
 490                return -ENODEV;
 491
 492        strncpy(mdiodev->modalias, bi->modalias,
 493                sizeof(mdiodev->modalias));
 494        mdiodev->bus_match = mdio_device_bus_match;
 495        mdiodev->dev.platform_data = (void *)bi->platform_data;
 496
 497        ret = mdio_device_register(mdiodev);
 498        if (ret)
 499                mdio_device_free(mdiodev);
 500
 501        return ret;
 502}
 503
 504/**
 505 * __mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
 506 * @bus: target mii_bus
 507 * @owner: module containing bus accessor functions
 508 *
 509 * Description: Called by a bus driver to bring up all the PHYs
 510 *   on a given bus, and attach them to the bus. Drivers should use
 511 *   mdiobus_register() rather than __mdiobus_register() unless they
 512 *   need to pass a specific owner module. MDIO devices which are not
 513 *   PHYs will not be brought up by this function. They are expected to
 514 *   to be explicitly listed in DT and instantiated by of_mdiobus_register().
 515 *
 516 * Returns 0 on success or < 0 on error.
 517 */
 518int __mdiobus_register(struct mii_bus *bus, struct module *owner)
 519{
 520        struct mdio_device *mdiodev;
 521        int i, err;
 522        struct gpio_desc *gpiod;
 523
 524        if (NULL == bus || NULL == bus->name ||
 525            NULL == bus->read || NULL == bus->write)
 526                return -EINVAL;
 527
 528        BUG_ON(bus->state != MDIOBUS_ALLOCATED &&
 529               bus->state != MDIOBUS_UNREGISTERED);
 530
 531        bus->owner = owner;
 532        bus->dev.parent = bus->parent;
 533        bus->dev.class = &mdio_bus_class;
 534        bus->dev.groups = NULL;
 535        dev_set_name(&bus->dev, "%s", bus->id);
 536
 537        err = device_register(&bus->dev);
 538        if (err) {
 539                pr_err("mii_bus %s failed to register\n", bus->id);
 540                return -EINVAL;
 541        }
 542
 543        mutex_init(&bus->mdio_lock);
 544        mutex_init(&bus->shared_lock);
 545
 546        /* de-assert bus level PHY GPIO reset */
 547        gpiod = devm_gpiod_get_optional(&bus->dev, "reset", GPIOD_OUT_LOW);
 548        if (IS_ERR(gpiod)) {
 549                dev_err(&bus->dev, "mii_bus %s couldn't get reset GPIO\n",
 550                        bus->id);
 551                device_del(&bus->dev);
 552                return PTR_ERR(gpiod);
 553        } else  if (gpiod) {
 554                bus->reset_gpiod = gpiod;
 555
 556                gpiod_set_value_cansleep(gpiod, 1);
 557                fsleep(bus->reset_delay_us);
 558                gpiod_set_value_cansleep(gpiod, 0);
 559                if (bus->reset_post_delay_us > 0)
 560                        fsleep(bus->reset_post_delay_us);
 561        }
 562
 563        if (bus->reset) {
 564                err = bus->reset(bus);
 565                if (err)
 566                        goto error_reset_gpiod;
 567        }
 568
 569        for (i = 0; i < PHY_MAX_ADDR; i++) {
 570                if ((bus->phy_mask & (1 << i)) == 0) {
 571                        struct phy_device *phydev;
 572
 573                        phydev = mdiobus_scan(bus, i);
 574                        if (IS_ERR(phydev) && (PTR_ERR(phydev) != -ENODEV)) {
 575                                err = PTR_ERR(phydev);
 576                                goto error;
 577                        }
 578                }
 579        }
 580
 581        mdiobus_setup_mdiodev_from_board_info(bus, mdiobus_create_device);
 582
 583        bus->state = MDIOBUS_REGISTERED;
 584        pr_info("%s: probed\n", bus->name);
 585        return 0;
 586
 587error:
 588        while (--i >= 0) {
 589                mdiodev = bus->mdio_map[i];
 590                if (!mdiodev)
 591                        continue;
 592
 593                mdiodev->device_remove(mdiodev);
 594                mdiodev->device_free(mdiodev);
 595        }
 596error_reset_gpiod:
 597        /* Put PHYs in RESET to save power */
 598        if (bus->reset_gpiod)
 599                gpiod_set_value_cansleep(bus->reset_gpiod, 1);
 600
 601        device_del(&bus->dev);
 602        return err;
 603}
 604EXPORT_SYMBOL(__mdiobus_register);
 605
 606void mdiobus_unregister(struct mii_bus *bus)
 607{
 608        struct mdio_device *mdiodev;
 609        int i;
 610
 611        BUG_ON(bus->state != MDIOBUS_REGISTERED);
 612        bus->state = MDIOBUS_UNREGISTERED;
 613
 614        for (i = 0; i < PHY_MAX_ADDR; i++) {
 615                mdiodev = bus->mdio_map[i];
 616                if (!mdiodev)
 617                        continue;
 618
 619                if (mdiodev->reset_gpio)
 620                        gpiod_put(mdiodev->reset_gpio);
 621
 622                mdiodev->device_remove(mdiodev);
 623                mdiodev->device_free(mdiodev);
 624        }
 625
 626        /* Put PHYs in RESET to save power */
 627        if (bus->reset_gpiod)
 628                gpiod_set_value_cansleep(bus->reset_gpiod, 1);
 629
 630        device_del(&bus->dev);
 631}
 632EXPORT_SYMBOL(mdiobus_unregister);
 633
 634/**
 635 * mdiobus_free - free a struct mii_bus
 636 * @bus: mii_bus to free
 637 *
 638 * This function releases the reference to the underlying device
 639 * object in the mii_bus.  If this is the last reference, the mii_bus
 640 * will be freed.
 641 */
 642void mdiobus_free(struct mii_bus *bus)
 643{
 644        /* For compatibility with error handling in drivers. */
 645        if (bus->state == MDIOBUS_ALLOCATED) {
 646                kfree(bus);
 647                return;
 648        }
 649
 650        BUG_ON(bus->state != MDIOBUS_UNREGISTERED);
 651        bus->state = MDIOBUS_RELEASED;
 652
 653        put_device(&bus->dev);
 654}
 655EXPORT_SYMBOL(mdiobus_free);
 656
 657/**
 658 * mdiobus_scan - scan a bus for MDIO devices.
 659 * @bus: mii_bus to scan
 660 * @addr: address on bus to scan
 661 *
 662 * This function scans the MDIO bus, looking for devices which can be
 663 * identified using a vendor/product ID in registers 2 and 3. Not all
 664 * MDIO devices have such registers, but PHY devices typically
 665 * do. Hence this function assumes anything found is a PHY, or can be
 666 * treated as a PHY. Other MDIO devices, such as switches, will
 667 * probably not be found during the scan.
 668 */
 669struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
 670{
 671        struct phy_device *phydev = ERR_PTR(-ENODEV);
 672        int err;
 673
 674        switch (bus->probe_capabilities) {
 675        case MDIOBUS_NO_CAP:
 676        case MDIOBUS_C22:
 677                phydev = get_phy_device(bus, addr, false);
 678                break;
 679        case MDIOBUS_C45:
 680                phydev = get_phy_device(bus, addr, true);
 681                break;
 682        case MDIOBUS_C22_C45:
 683                phydev = get_phy_device(bus, addr, false);
 684                if (IS_ERR(phydev))
 685                        phydev = get_phy_device(bus, addr, true);
 686                break;
 687        }
 688
 689        if (IS_ERR(phydev))
 690                return phydev;
 691
 692        /*
 693         * For DT, see if the auto-probed phy has a correspoding child
 694         * in the bus node, and set the of_node pointer in this case.
 695         */
 696        of_mdiobus_link_mdiodev(bus, &phydev->mdio);
 697
 698        err = phy_device_register(phydev);
 699        if (err) {
 700                phy_device_free(phydev);
 701                return ERR_PTR(-ENODEV);
 702        }
 703
 704        return phydev;
 705}
 706EXPORT_SYMBOL(mdiobus_scan);
 707
 708static void mdiobus_stats_acct(struct mdio_bus_stats *stats, bool op, int ret)
 709{
 710        preempt_disable();
 711        u64_stats_update_begin(&stats->syncp);
 712
 713        u64_stats_inc(&stats->transfers);
 714        if (ret < 0) {
 715                u64_stats_inc(&stats->errors);
 716                goto out;
 717        }
 718
 719        if (op)
 720                u64_stats_inc(&stats->reads);
 721        else
 722                u64_stats_inc(&stats->writes);
 723out:
 724        u64_stats_update_end(&stats->syncp);
 725        preempt_enable();
 726}
 727
 728/**
 729 * __mdiobus_read - Unlocked version of the mdiobus_read function
 730 * @bus: the mii_bus struct
 731 * @addr: the phy address
 732 * @regnum: register number to read
 733 *
 734 * Read a MDIO bus register. Caller must hold the mdio bus lock.
 735 *
 736 * NOTE: MUST NOT be called from interrupt context.
 737 */
 738int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
 739{
 740        int retval;
 741
 742        WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
 743
 744        retval = bus->read(bus, addr, regnum);
 745
 746        trace_mdio_access(bus, 1, addr, regnum, retval, retval);
 747        mdiobus_stats_acct(&bus->stats[addr], true, retval);
 748
 749        return retval;
 750}
 751EXPORT_SYMBOL(__mdiobus_read);
 752
 753/**
 754 * __mdiobus_write - Unlocked version of the mdiobus_write function
 755 * @bus: the mii_bus struct
 756 * @addr: the phy address
 757 * @regnum: register number to write
 758 * @val: value to write to @regnum
 759 *
 760 * Write a MDIO bus register. Caller must hold the mdio bus lock.
 761 *
 762 * NOTE: MUST NOT be called from interrupt context.
 763 */
 764int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
 765{
 766        int err;
 767
 768        WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
 769
 770        err = bus->write(bus, addr, regnum, val);
 771
 772        trace_mdio_access(bus, 0, addr, regnum, val, err);
 773        mdiobus_stats_acct(&bus->stats[addr], false, err);
 774
 775        return err;
 776}
 777EXPORT_SYMBOL(__mdiobus_write);
 778
 779/**
 780 * __mdiobus_modify_changed - Unlocked version of the mdiobus_modify function
 781 * @bus: the mii_bus struct
 782 * @addr: the phy address
 783 * @regnum: register number to modify
 784 * @mask: bit mask of bits to clear
 785 * @set: bit mask of bits to set
 786 *
 787 * Read, modify, and if any change, write the register value back to the
 788 * device. Any error returns a negative number.
 789 *
 790 * NOTE: MUST NOT be called from interrupt context.
 791 */
 792int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
 793                             u16 mask, u16 set)
 794{
 795        int new, ret;
 796
 797        ret = __mdiobus_read(bus, addr, regnum);
 798        if (ret < 0)
 799                return ret;
 800
 801        new = (ret & ~mask) | set;
 802        if (new == ret)
 803                return 0;
 804
 805        ret = __mdiobus_write(bus, addr, regnum, new);
 806
 807        return ret < 0 ? ret : 1;
 808}
 809EXPORT_SYMBOL_GPL(__mdiobus_modify_changed);
 810
 811/**
 812 * mdiobus_read_nested - Nested version of the mdiobus_read function
 813 * @bus: the mii_bus struct
 814 * @addr: the phy address
 815 * @regnum: register number to read
 816 *
 817 * In case of nested MDIO bus access avoid lockdep false positives by
 818 * using mutex_lock_nested().
 819 *
 820 * NOTE: MUST NOT be called from interrupt context,
 821 * because the bus read/write functions may wait for an interrupt
 822 * to conclude the operation.
 823 */
 824int mdiobus_read_nested(struct mii_bus *bus, int addr, u32 regnum)
 825{
 826        int retval;
 827
 828        mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
 829        retval = __mdiobus_read(bus, addr, regnum);
 830        mutex_unlock(&bus->mdio_lock);
 831
 832        return retval;
 833}
 834EXPORT_SYMBOL(mdiobus_read_nested);
 835
 836/**
 837 * mdiobus_read - Convenience function for reading a given MII mgmt register
 838 * @bus: the mii_bus struct
 839 * @addr: the phy address
 840 * @regnum: register number to read
 841 *
 842 * NOTE: MUST NOT be called from interrupt context,
 843 * because the bus read/write functions may wait for an interrupt
 844 * to conclude the operation.
 845 */
 846int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
 847{
 848        int retval;
 849
 850        mutex_lock(&bus->mdio_lock);
 851        retval = __mdiobus_read(bus, addr, regnum);
 852        mutex_unlock(&bus->mdio_lock);
 853
 854        return retval;
 855}
 856EXPORT_SYMBOL(mdiobus_read);
 857
 858/**
 859 * mdiobus_write_nested - Nested version of the mdiobus_write function
 860 * @bus: the mii_bus struct
 861 * @addr: the phy address
 862 * @regnum: register number to write
 863 * @val: value to write to @regnum
 864 *
 865 * In case of nested MDIO bus access avoid lockdep false positives by
 866 * using mutex_lock_nested().
 867 *
 868 * NOTE: MUST NOT be called from interrupt context,
 869 * because the bus read/write functions may wait for an interrupt
 870 * to conclude the operation.
 871 */
 872int mdiobus_write_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val)
 873{
 874        int err;
 875
 876        mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
 877        err = __mdiobus_write(bus, addr, regnum, val);
 878        mutex_unlock(&bus->mdio_lock);
 879
 880        return err;
 881}
 882EXPORT_SYMBOL(mdiobus_write_nested);
 883
 884/**
 885 * mdiobus_write - Convenience function for writing a given MII mgmt register
 886 * @bus: the mii_bus struct
 887 * @addr: the phy address
 888 * @regnum: register number to write
 889 * @val: value to write to @regnum
 890 *
 891 * NOTE: MUST NOT be called from interrupt context,
 892 * because the bus read/write functions may wait for an interrupt
 893 * to conclude the operation.
 894 */
 895int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
 896{
 897        int err;
 898
 899        mutex_lock(&bus->mdio_lock);
 900        err = __mdiobus_write(bus, addr, regnum, val);
 901        mutex_unlock(&bus->mdio_lock);
 902
 903        return err;
 904}
 905EXPORT_SYMBOL(mdiobus_write);
 906
 907/**
 908 * mdiobus_modify - Convenience function for modifying a given mdio device
 909 *      register
 910 * @bus: the mii_bus struct
 911 * @addr: the phy address
 912 * @regnum: register number to write
 913 * @mask: bit mask of bits to clear
 914 * @set: bit mask of bits to set
 915 */
 916int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask, u16 set)
 917{
 918        int err;
 919
 920        mutex_lock(&bus->mdio_lock);
 921        err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
 922        mutex_unlock(&bus->mdio_lock);
 923
 924        return err < 0 ? err : 0;
 925}
 926EXPORT_SYMBOL_GPL(mdiobus_modify);
 927
 928/**
 929 * mdio_bus_match - determine if given MDIO driver supports the given
 930 *                  MDIO device
 931 * @dev: target MDIO device
 932 * @drv: given MDIO driver
 933 *
 934 * Description: Given a MDIO device, and a MDIO driver, return 1 if
 935 *   the driver supports the device.  Otherwise, return 0. This may
 936 *   require calling the devices own match function, since different classes
 937 *   of MDIO devices have different match criteria.
 938 */
 939static int mdio_bus_match(struct device *dev, struct device_driver *drv)
 940{
 941        struct mdio_device *mdio = to_mdio_device(dev);
 942
 943        if (of_driver_match_device(dev, drv))
 944                return 1;
 945
 946        if (mdio->bus_match)
 947                return mdio->bus_match(dev, drv);
 948
 949        return 0;
 950}
 951
 952static int mdio_uevent(struct device *dev, struct kobj_uevent_env *env)
 953{
 954        int rc;
 955
 956        /* Some devices have extra OF data and an OF-style MODALIAS */
 957        rc = of_device_uevent_modalias(dev, env);
 958        if (rc != -ENODEV)
 959                return rc;
 960
 961        return 0;
 962}
 963
 964static struct attribute *mdio_bus_device_statistics_attrs[] = {
 965        &dev_attr_mdio_bus_device_transfers.attr.attr,
 966        &dev_attr_mdio_bus_device_errors.attr.attr,
 967        &dev_attr_mdio_bus_device_writes.attr.attr,
 968        &dev_attr_mdio_bus_device_reads.attr.attr,
 969        NULL,
 970};
 971
 972static const struct attribute_group mdio_bus_device_statistics_group = {
 973        .name   = "statistics",
 974        .attrs  = mdio_bus_device_statistics_attrs,
 975};
 976
 977static const struct attribute_group *mdio_bus_dev_groups[] = {
 978        &mdio_bus_device_statistics_group,
 979        NULL,
 980};
 981
 982struct bus_type mdio_bus_type = {
 983        .name           = "mdio_bus",
 984        .dev_groups     = mdio_bus_dev_groups,
 985        .match          = mdio_bus_match,
 986        .uevent         = mdio_uevent,
 987};
 988EXPORT_SYMBOL(mdio_bus_type);
 989
 990int __init mdio_bus_init(void)
 991{
 992        int ret;
 993
 994        ret = class_register(&mdio_bus_class);
 995        if (!ret) {
 996                ret = bus_register(&mdio_bus_type);
 997                if (ret)
 998                        class_unregister(&mdio_bus_class);
 999        }
1000
1001        return ret;
1002}
1003EXPORT_SYMBOL_GPL(mdio_bus_init);
1004
1005#if IS_ENABLED(CONFIG_PHYLIB)
1006void mdio_bus_exit(void)
1007{
1008        class_unregister(&mdio_bus_class);
1009        bus_unregister(&mdio_bus_type);
1010}
1011EXPORT_SYMBOL_GPL(mdio_bus_exit);
1012#else
1013module_init(mdio_bus_init);
1014/* no module_exit, intentional */
1015MODULE_LICENSE("GPL");
1016MODULE_DESCRIPTION("MDIO bus/device layer");
1017#endif
1018