drivers/net/phy/mdio_bus.c

   1 /* MDIO Bus interface
   2  *
   3  * Author: Andy Fleming
   4  *
   5  * Copyright (c) 2004 Freescale Semiconductor, Inc.
   6  *
   7  * This program is free software; you can redistribute  it and/or modify it
   8  * under  the terms of  the GNU General  Public License as published by the
   9  * Free Software Foundation;  either version 2 of the  License, or (at your
  10  * option) any later version.
  11  *
  12  */
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/kernel.h>
  17 #include <linux/string.h>
  18 #include <linux/errno.h>
  19 #include <linux/unistd.h>
  20 #include <linux/slab.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/init.h>
  23 #include <linux/delay.h>
  24 #include <linux/device.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_mdio.h>
  27 #include <linux/netdevice.h>
  28 #include <linux/etherdevice.h>
  29 #include <linux/skbuff.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/mm.h>
  32 #include <linux/module.h>
  33 #include <linux/mii.h>
  34 #include <linux/ethtool.h>
  35 #include <linux/phy.h>
  36 #include <linux/io.h>
  37 #include <linux/uaccess.h>
  38
  39 #include <asm/irq.h>
  40
  41 int mdiobus_register_device(struct mdio_device *mdiodev)
  42 {
  43         if (mdiodev->bus->mdio_map[mdiodev->addr])
  44                 return -EBUSY;
  45
  46         mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
  47
  48         return 0;
  49 }
  50 EXPORT_SYMBOL(mdiobus_register_device);
  51
  52 int mdiobus_unregister_device(struct mdio_device *mdiodev)
  53 {
  54         if (mdiodev->bus->mdio_map[mdiodev->addr] != mdiodev)
  55                 return -EINVAL;
  56
  57         mdiodev->bus->mdio_map[mdiodev->addr] = NULL;
  58
  59         return 0;
  60 }
  61 EXPORT_SYMBOL(mdiobus_unregister_device);
  62
  63 struct phy_device *mdiobus_get_phy(struct mii_bus *bus, int addr)
  64 {
  65         struct mdio_device *mdiodev = bus->mdio_map[addr];
  66
  67         if (!mdiodev)
  68                 return NULL;
  69
  70         if (!(mdiodev->flags & MDIO_DEVICE_FLAG_PHY))
  71                 return NULL;
  72
  73         return container_of(mdiodev, struct phy_device, mdio);
  74 }
  75 EXPORT_SYMBOL(mdiobus_get_phy);
  76
  77 bool mdiobus_is_registered_device(struct mii_bus *bus, int addr)
  78 {
  79         return bus->mdio_map[addr];
  80 }
  81 EXPORT_SYMBOL(mdiobus_is_registered_device);
  82
  83 /**
  84  * mdiobus_alloc_size - allocate a mii_bus structure
  85  * @size: extra amount of memory to allocate for private storage.
  86  * If non-zero, then bus->priv is points to that memory.
  87  *
  88  * Description: called by a bus driver to allocate an mii_bus
  89  * structure to fill in.
  90  */
  91 struct mii_bus *mdiobus_alloc_size(size_t size)
  92 {
  93         struct mii_bus *bus;
  94         size_t aligned_size = ALIGN(sizeof(*bus), NETDEV_ALIGN);
  95         size_t alloc_size;
  96         int i;
  97
  98         /* If we alloc extra space, it should be aligned */
  99         if (size)
 100                 alloc_size = aligned_size + size;
 101         else
 102                 alloc_size = sizeof(*bus);
 103
 104         bus = kzalloc(alloc_size, GFP_KERNEL);
 105         if (bus) {
 106                 bus->state = MDIOBUS_ALLOCATED;
 107                 if (size)
 108                         bus->priv = (void *)bus + aligned_size;
 109         }
 110
 111         /* Initialise the interrupts to polling */
 112         for (i = 0; i < PHY_MAX_ADDR; i++)
 113                 bus->irq[i] = PHY_POLL;
 114
 115         return bus;
 116 }
 117 EXPORT_SYMBOL(mdiobus_alloc_size);
 118
 119 static void _devm_mdiobus_free(struct device *dev, void *res)
 120 {
 121         mdiobus_free(*(struct mii_bus **)res);
 122 }
 123
 124 static int devm_mdiobus_match(struct device *dev, void *res, void *data)
 125 {
 126         struct mii_bus **r = res;
 127
 128         if (WARN_ON(!r || !*r))
 129                 return 0;
 130
 131         return *r == data;
 132 }
 133
 134 /**
 135  * devm_mdiobus_alloc_size - Resource-managed mdiobus_alloc_size()
 136  * @dev:                Device to allocate mii_bus for
 137  * @sizeof_priv:        Space to allocate for private structure.
 138  *
 139  * Managed mdiobus_alloc_size. mii_bus allocated with this function is
 140  * automatically freed on driver detach.
 141  *
 142  * If an mii_bus allocated with this function needs to be freed separately,
 143  * devm_mdiobus_free() must be used.
 144  *
 145  * RETURNS:
 146  * Pointer to allocated mii_bus on success, NULL on failure.
 147  */
 148 struct mii_bus *devm_mdiobus_alloc_size(struct device *dev, int sizeof_priv)
 149 {
 150         struct mii_bus **ptr, *bus;
 151
 152         ptr = devres_alloc(_devm_mdiobus_free, sizeof(*ptr), GFP_KERNEL);
 153         if (!ptr)
 154                 return NULL;
 155
 156         /* use raw alloc_dr for kmalloc caller tracing */
 157         bus = mdiobus_alloc_size(sizeof_priv);
 158         if (bus) {
 159                 *ptr = bus;
 160                 devres_add(dev, ptr);
 161         } else {
 162                 devres_free(ptr);
 163         }
 164
 165         return bus;
 166 }
 167 EXPORT_SYMBOL_GPL(devm_mdiobus_alloc_size);
 168
 169 /**
 170  * devm_mdiobus_free - Resource-managed mdiobus_free()
 171  * @dev:                Device this mii_bus belongs to
 172  * @bus:                the mii_bus associated with the device
 173  *
 174  * Free mii_bus allocated with devm_mdiobus_alloc_size().
 175  */
 176 void devm_mdiobus_free(struct device *dev, struct mii_bus *bus)
 177 {
 178         int rc;
 179
 180         rc = devres_release(dev, _devm_mdiobus_free,
 181                             devm_mdiobus_match, bus);
 182         WARN_ON(rc);
 183 }
 184 EXPORT_SYMBOL_GPL(devm_mdiobus_free);
 185
 186 /**
 187  * mdiobus_release - mii_bus device release callback
 188  * @d: the target struct device that contains the mii_bus
 189  *
 190  * Description: called when the last reference to an mii_bus is
 191  * dropped, to free the underlying memory.
 192  */
 193 static void mdiobus_release(struct device *d)
 194 {
 195         struct mii_bus *bus = to_mii_bus(d);
 196         BUG_ON(bus->state != MDIOBUS_RELEASED &&
 197                /* for compatibility with error handling in drivers */
 198                bus->state != MDIOBUS_ALLOCATED);
 199         kfree(bus);
 200 }
 201
 202 static struct class mdio_bus_class = {
 203         .name           = "mdio_bus",
 204         .dev_release    = mdiobus_release,
 205 };
 206
 207 #if IS_ENABLED(CONFIG_OF_MDIO)
 208 /* Helper function for of_mdio_find_bus */
 209 static int of_mdio_bus_match(struct device *dev, const void *mdio_bus_np)
 210 {
 211         return dev->of_node == mdio_bus_np;
 212 }
 213 /**
 214  * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
 215  * @mdio_bus_np: Pointer to the mii_bus.
 216  *
 217  * Returns a reference to the mii_bus, or NULL if none found.  The
 218  * embedded struct device will have its reference count incremented,
 219  * and this must be put once the bus is finished with.
 220  *
 221  * Because the association of a device_node and mii_bus is made via
 222  * of_mdiobus_register(), the mii_bus cannot be found before it is
 223  * registered with of_mdiobus_register().
 224  *
 225  */
 226 struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
 227 {
 228         struct device *d;
 229
 230         if (!mdio_bus_np)
 231                 return NULL;
 232
 233         d = class_find_device(&mdio_bus_class, NULL,  mdio_bus_np,
 234                               of_mdio_bus_match);
 235
 236         return d ? to_mii_bus(d) : NULL;
 237 }
 238 EXPORT_SYMBOL(of_mdio_find_bus);
 239
 240 /* Walk the list of subnodes of a mdio bus and look for a node that
 241  * matches the mdio device's address with its 'reg' property. If
 242  * found, set the of_node pointer for the mdio device. This allows
 243  * auto-probed phy devices to be supplied with information passed in
 244  * via DT.
 245  */
 246 static void of_mdiobus_link_mdiodev(struct mii_bus *bus,
 247                                     struct mdio_device *mdiodev)
 248 {
 249         struct device *dev = &mdiodev->dev;
 250         struct device_node *child;
 251
 252         if (dev->of_node || !bus->dev.of_node)
 253                 return;
 254
 255         for_each_available_child_of_node(bus->dev.of_node, child) {
 256                 int addr;
 257                 int ret;
 258
 259                 ret = of_property_read_u32(child, "reg", &addr);
 260                 if (ret < 0) {
 261                         dev_err(dev, "%s has invalid MDIO address\n",
 262                                 child->full_name);
 263                         continue;
 264                 }
 265
 266                 /* A MDIO device must have a reg property in the range [0-31] */
 267                 if (addr >= PHY_MAX_ADDR) {
 268                         dev_err(dev, "%s MDIO address %i is too large\n",
 269                                 child->full_name, addr);
 270                         continue;
 271                 }
 272
 273                 if (addr == mdiodev->addr) {
 274                         dev->of_node = child;
 275                         return;
 276                 }
 277         }
 278 }
 279 #else /* !IS_ENABLED(CONFIG_OF_MDIO) */
 280 static inline void of_mdiobus_link_mdiodev(struct mii_bus *mdio,
 281                                            struct mdio_device *mdiodev)
 282 {
 283 }
 284 #endif
 285
 286 /**
 287  * __mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
 288  * @bus: target mii_bus
 289  * @owner: module containing bus accessor functions
 290  *
 291  * Description: Called by a bus driver to bring up all the PHYs
 292  *   on a given bus, and attach them to the bus. Drivers should use
 293  *   mdiobus_register() rather than __mdiobus_register() unless they
 294  *   need to pass a specific owner module. MDIO devices which are not
 295  *   PHYs will not be brought up by this function. They are expected to
 296  *   to be explicitly listed in DT and instantiated by of_mdiobus_register().
 297  *
 298  * Returns 0 on success or < 0 on error.
 299  */
 300 int __mdiobus_register(struct mii_bus *bus, struct module *owner)
 301 {
 302         struct mdio_device *mdiodev;
 303         int i, err;
 304
 305         if (NULL == bus || NULL == bus->name ||
 306             NULL == bus->read || NULL == bus->write)
 307                 return -EINVAL;
 308
 309         BUG_ON(bus->state != MDIOBUS_ALLOCATED &&
 310                bus->state != MDIOBUS_UNREGISTERED);
 311
 312         bus->owner = owner;
 313         bus->dev.parent = bus->parent;
 314         bus->dev.class = &mdio_bus_class;
 315         bus->dev.groups = NULL;
 316         dev_set_name(&bus->dev, "%s", bus->id);
 317
 318         err = device_register(&bus->dev);
 319         if (err) {
 320                 pr_err("mii_bus %s failed to register\n", bus->id);
 321                 put_device(&bus->dev);
 322                 return -EINVAL;
 323         }
 324
 325         mutex_init(&bus->mdio_lock);
 326
 327         if (bus->reset)
 328                 bus->reset(bus);
 329
 330         for (i = 0; i < PHY_MAX_ADDR; i++) {
 331                 if ((bus->phy_mask & (1 << i)) == 0) {
 332                         struct phy_device *phydev;
 333
 334                         phydev = mdiobus_scan(bus, i);
 335                         if (IS_ERR(phydev)) {
 336                                 err = PTR_ERR(phydev);
 337                                 goto error;
 338                         }
 339                 }
 340         }
 341
 342         bus->state = MDIOBUS_REGISTERED;
 343         pr_info("%s: probed\n", bus->name);
 344         return 0;
 345
 346 error:
 347         while (--i >= 0) {
 348                 mdiodev = bus->mdio_map[i];
 349                 if (!mdiodev)
 350                         continue;
 351
 352                 mdiodev->device_remove(mdiodev);
 353                 mdiodev->device_free(mdiodev);
 354         }
 355         device_del(&bus->dev);
 356         return err;
 357 }
 358 EXPORT_SYMBOL(__mdiobus_register);
 359
 360 void mdiobus_unregister(struct mii_bus *bus)
 361 {
 362         struct mdio_device *mdiodev;
 363         int i;
 364
 365         BUG_ON(bus->state != MDIOBUS_REGISTERED);
 366         bus->state = MDIOBUS_UNREGISTERED;
 367
 368         for (i = 0; i < PHY_MAX_ADDR; i++) {
 369                 mdiodev = bus->mdio_map[i];
 370                 if (!mdiodev)
 371                         continue;
 372
 373                 mdiodev->device_remove(mdiodev);
 374                 mdiodev->device_free(mdiodev);
 375         }
 376         device_del(&bus->dev);
 377 }
 378 EXPORT_SYMBOL(mdiobus_unregister);
 379
 380 /**
 381  * mdiobus_free - free a struct mii_bus
 382  * @bus: mii_bus to free
 383  *
 384  * This function releases the reference to the underlying device
 385  * object in the mii_bus.  If this is the last reference, the mii_bus
 386  * will be freed.
 387  */
 388 void mdiobus_free(struct mii_bus *bus)
 389 {
 390         /* For compatibility with error handling in drivers. */
 391         if (bus->state == MDIOBUS_ALLOCATED) {
 392                 kfree(bus);
 393                 return;
 394         }
 395
 396         BUG_ON(bus->state != MDIOBUS_UNREGISTERED);
 397         bus->state = MDIOBUS_RELEASED;
 398
 399         put_device(&bus->dev);
 400 }
 401 EXPORT_SYMBOL(mdiobus_free);
 402
 403 /**
 404  * mdiobus_scan - scan a bus for MDIO devices.
 405  * @bus: mii_bus to scan
 406  * @addr: address on bus to scan
 407  *
 408  * This function scans the MDIO bus, looking for devices which can be
 409  * identified using a vendor/product ID in registers 2 and 3. Not all
 410  * MDIO devices have such registers, but PHY devices typically
 411  * do. Hence this function assumes anything found is a PHY, or can be
 412  * treated as a PHY. Other MDIO devices, such as switches, will
 413  * probably not be found during the scan.
 414  */
 415 struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
 416 {
 417         struct phy_device *phydev;
 418         int err;
 419
 420         phydev = get_phy_device(bus, addr, false);
 421         if (IS_ERR(phydev) || phydev == NULL)
 422                 return phydev;
 423
 424         /*
 425          * For DT, see if the auto-probed phy has a correspoding child
 426          * in the bus node, and set the of_node pointer in this case.
 427          */
 428         of_mdiobus_link_mdiodev(bus, &phydev->mdio);
 429
 430         err = phy_device_register(phydev);
 431         if (err) {
 432                 phy_device_free(phydev);
 433                 return NULL;
 434         }
 435
 436         return phydev;
 437 }
 438 EXPORT_SYMBOL(mdiobus_scan);
 439
 440 /**
 441  * mdiobus_read_nested - Nested version of the mdiobus_read function
 442  * @bus: the mii_bus struct
 443  * @addr: the phy address
 444  * @regnum: register number to read
 445  *
 446  * In case of nested MDIO bus access avoid lockdep false positives by
 447  * using mutex_lock_nested().
 448  *
 449  * NOTE: MUST NOT be called from interrupt context,
 450  * because the bus read/write functions may wait for an interrupt
 451  * to conclude the operation.
 452  */
 453 int mdiobus_read_nested(struct mii_bus *bus, int addr, u32 regnum)
 454 {
 455         int retval;
 456
 457         BUG_ON(in_interrupt());
 458
 459         mutex_lock_nested(&bus->mdio_lock, SINGLE_DEPTH_NESTING);
 460         retval = bus->read(bus, addr, regnum);
 461         mutex_unlock(&bus->mdio_lock);
 462
 463         return retval;
 464 }
 465 EXPORT_SYMBOL(mdiobus_read_nested);
 466
 467 /**
 468  * mdiobus_read - Convenience function for reading a given MII mgmt register
 469  * @bus: the mii_bus struct
 470  * @addr: the phy address
 471  * @regnum: register number to read
 472  *
 473  * NOTE: MUST NOT be called from interrupt context,
 474  * because the bus read/write functions may wait for an interrupt
 475  * to conclude the operation.
 476  */
 477 int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
 478 {
 479         int retval;
 480
 481         BUG_ON(in_interrupt());
 482
 483         mutex_lock(&bus->mdio_lock);
 484         retval = bus->read(bus, addr, regnum);
 485         mutex_unlock(&bus->mdio_lock);
 486
 487         return retval;
 488 }
 489 EXPORT_SYMBOL(mdiobus_read);
 490
 491 /**
 492  * mdiobus_write_nested - Nested version of the mdiobus_write function
 493  * @bus: the mii_bus struct
 494  * @addr: the phy address
 495  * @regnum: register number to write
 496  * @val: value to write to @regnum
 497  *
 498  * In case of nested MDIO bus access avoid lockdep false positives by
 499  * using mutex_lock_nested().
 500  *
 501  * NOTE: MUST NOT be called from interrupt context,
 502  * because the bus read/write functions may wait for an interrupt
 503  * to conclude the operation.
 504  */
 505 int mdiobus_write_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val)
 506 {
 507         int err;
 508
 509         BUG_ON(in_interrupt());
 510
 511         mutex_lock_nested(&bus->mdio_lock, SINGLE_DEPTH_NESTING);
 512         err = bus->write(bus, addr, regnum, val);
 513         mutex_unlock(&bus->mdio_lock);
 514
 515         return err;
 516 }
 517 EXPORT_SYMBOL(mdiobus_write_nested);
 518
 519 /**
 520  * mdiobus_write - Convenience function for writing a given MII mgmt register
 521  * @bus: the mii_bus struct
 522  * @addr: the phy address
 523  * @regnum: register number to write
 524  * @val: value to write to @regnum
 525  *
 526  * NOTE: MUST NOT be called from interrupt context,
 527  * because the bus read/write functions may wait for an interrupt
 528  * to conclude the operation.
 529  */
 530 int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
 531 {
 532         int err;
 533
 534         BUG_ON(in_interrupt());
 535
 536         mutex_lock(&bus->mdio_lock);
 537         err = bus->write(bus, addr, regnum, val);
 538         mutex_unlock(&bus->mdio_lock);
 539
 540         return err;
 541 }
 542 EXPORT_SYMBOL(mdiobus_write);
 543
 544 /**
 545  * mdio_bus_match - determine if given MDIO driver supports the given
 546  *                  MDIO device
 547  * @dev: target MDIO device
 548  * @drv: given MDIO driver
 549  *
 550  * Description: Given a MDIO device, and a MDIO driver, return 1 if
 551  *   the driver supports the device.  Otherwise, return 0. This may
 552  *   require calling the devices own match function, since different classes
 553  *   of MDIO devices have different match criteria.
 554  */
 555 static int mdio_bus_match(struct device *dev, struct device_driver *drv)
 556 {
 557         struct mdio_device *mdio = to_mdio_device(dev);
 558
 559         if (of_driver_match_device(dev, drv))
 560                 return 1;
 561
 562         if (mdio->bus_match)
 563                 return mdio->bus_match(dev, drv);
 564
 565         return 0;
 566 }
 567
 568 #ifdef CONFIG_PM
 569 static int mdio_bus_suspend(struct device *dev)
 570 {
 571         struct mdio_device *mdio = to_mdio_device(dev);
 572
 573         if (mdio->pm_ops && mdio->pm_ops->suspend)
 574                 return mdio->pm_ops->suspend(dev);
 575
 576         return 0;
 577 }
 578
 579 static int mdio_bus_resume(struct device *dev)
 580 {
 581         struct mdio_device *mdio = to_mdio_device(dev);
 582
 583         if (mdio->pm_ops && mdio->pm_ops->resume)
 584                 return mdio->pm_ops->resume(dev);
 585
 586         return 0;
 587 }
 588
 589 static int mdio_bus_restore(struct device *dev)
 590 {
 591         struct mdio_device *mdio = to_mdio_device(dev);
 592
 593         if (mdio->pm_ops && mdio->pm_ops->restore)
 594                 return mdio->pm_ops->restore(dev);
 595
 596         return 0;
 597 }
 598
 599 static const struct dev_pm_ops mdio_bus_pm_ops = {
 600         .suspend = mdio_bus_suspend,
 601         .resume = mdio_bus_resume,
 602         .freeze = mdio_bus_suspend,
 603         .thaw = mdio_bus_resume,
 604         .restore = mdio_bus_restore,
 605 };
 606
 607 #define MDIO_BUS_PM_OPS (&mdio_bus_pm_ops)
 608
 609 #else
 610
 611 #define MDIO_BUS_PM_OPS NULL
 612
 613 #endif /* CONFIG_PM */
 614
 615 struct bus_type mdio_bus_type = {
 616         .name           = "mdio_bus",
 617         .match          = mdio_bus_match,
 618         .pm             = MDIO_BUS_PM_OPS,
 619 };
 620 EXPORT_SYMBOL(mdio_bus_type);
 621
 622 int __init mdio_bus_init(void)
 623 {
 624         int ret;
 625
 626         ret = class_register(&mdio_bus_class);
 627         if (!ret) {
 628                 ret = bus_register(&mdio_bus_type);
 629                 if (ret)
 630                         class_unregister(&mdio_bus_class);
 631         }
 632
 633         return ret;
 634 }
 635
 636 void mdio_bus_exit(void)
 637 {
 638         class_unregister(&mdio_bus_class);
 639         bus_unregister(&mdio_bus_type);
 640 }