drivers/net/phy/mdio_bus.c

   1 /*
   2  * drivers/net/phy/mdio_bus.c
   3  *
   4  * MDIO Bus interface
   5  *
   6  * Author: Andy Fleming
   7  *
   8  * Copyright (c) 2004 Freescale Semiconductor, Inc.
   9  *
  10  * This program is free software; you can redistribute  it and/or modify it
  11  * under  the terms of  the GNU General  Public License as published by the
  12  * Free Software Foundation;  either version 2 of the  License, or (at your
  13  * option) any later version.
  14  *
  15  */
  16
  17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18
  19 #include <linux/kernel.h>
  20 #include <linux/string.h>
  21 #include <linux/errno.h>
  22 #include <linux/unistd.h>
  23 #include <linux/slab.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/init.h>
  26 #include <linux/delay.h>
  27 #include <linux/device.h>
  28 #include <linux/of_device.h>
  29 #include <linux/of_mdio.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/etherdevice.h>
  32 #include <linux/skbuff.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/mm.h>
  35 #include <linux/module.h>
  36 #include <linux/mii.h>
  37 #include <linux/ethtool.h>
  38 #include <linux/phy.h>
  39
  40 #include <asm/io.h>
  41 #include <asm/irq.h>
  42 #include <asm/uaccess.h>
  43
  44 /**
  45  * mdiobus_alloc_size - allocate a mii_bus structure
  46  * @size: extra amount of memory to allocate for private storage.
  47  * If non-zero, then bus->priv is points to that memory.
  48  *
  49  * Description: called by a bus driver to allocate an mii_bus
  50  * structure to fill in.
  51  */
  52 struct mii_bus *mdiobus_alloc_size(size_t size)
  53 {
  54         struct mii_bus *bus;
  55         size_t aligned_size = ALIGN(sizeof(*bus), NETDEV_ALIGN);
  56         size_t alloc_size;
  57
  58         /* If we alloc extra space, it should be aligned */
  59         if (size)
  60                 alloc_size = aligned_size + size;
  61         else
  62                 alloc_size = sizeof(*bus);
  63
  64         bus = kzalloc(alloc_size, GFP_KERNEL);
  65         if (bus) {
  66                 bus->state = MDIOBUS_ALLOCATED;
  67                 if (size)
  68                         bus->priv = (void *)bus + aligned_size;
  69         }
  70
  71         return bus;
  72 }
  73 EXPORT_SYMBOL(mdiobus_alloc_size);
  74
  75 /**
  76  * mdiobus_release - mii_bus device release callback
  77  * @d: the target struct device that contains the mii_bus
  78  *
  79  * Description: called when the last reference to an mii_bus is
  80  * dropped, to free the underlying memory.
  81  */
  82 static void mdiobus_release(struct device *d)
  83 {
  84         struct mii_bus *bus = to_mii_bus(d);
  85         BUG_ON(bus->state != MDIOBUS_RELEASED &&
  86                /* for compatibility with error handling in drivers */
  87                bus->state != MDIOBUS_ALLOCATED);
  88         kfree(bus);
  89 }
  90
  91 static struct class mdio_bus_class = {
  92         .name           = "mdio_bus",
  93         .dev_release    = mdiobus_release,
  94 };
  95
  96 #if IS_ENABLED(CONFIG_OF_MDIO)
  97 /* Helper function for of_mdio_find_bus */
  98 static int of_mdio_bus_match(struct device *dev, const void *mdio_bus_np)
  99 {
 100         return dev->of_node == mdio_bus_np;
 101 }
 102 /**
 103  * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
 104  * @mdio_bus_np: Pointer to the mii_bus.
 105  *
 106  * Returns a pointer to the mii_bus, or NULL if none found.
 107  *
 108  * Because the association of a device_node and mii_bus is made via
 109  * of_mdiobus_register(), the mii_bus cannot be found before it is
 110  * registered with of_mdiobus_register().
 111  *
 112  */
 113 struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
 114 {
 115         struct device *d;
 116
 117         if (!mdio_bus_np)
 118                 return NULL;
 119
 120         d = class_find_device(&mdio_bus_class, NULL,  mdio_bus_np,
 121                               of_mdio_bus_match);
 122
 123         return d ? to_mii_bus(d) : NULL;
 124 }
 125 EXPORT_SYMBOL(of_mdio_find_bus);
 126 #endif
 127
 128 /**
 129  * mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
 130  * @bus: target mii_bus
 131  *
 132  * Description: Called by a bus driver to bring up all the PHYs
 133  *   on a given bus, and attach them to the bus.
 134  *
 135  * Returns 0 on success or < 0 on error.
 136  */
 137 int mdiobus_register(struct mii_bus *bus)
 138 {
 139         int i, err;
 140
 141         if (NULL == bus || NULL == bus->name ||
 142                         NULL == bus->read ||
 143                         NULL == bus->write)
 144                 return -EINVAL;
 145
 146         BUG_ON(bus->state != MDIOBUS_ALLOCATED &&
 147                bus->state != MDIOBUS_UNREGISTERED);
 148
 149         bus->dev.parent = bus->parent;
 150         bus->dev.class = &mdio_bus_class;
 151         bus->dev.groups = NULL;
 152         dev_set_name(&bus->dev, "%s", bus->id);
 153
 154         err = device_register(&bus->dev);
 155         if (err) {
 156                 pr_err("mii_bus %s failed to register\n", bus->id);
 157                 return -EINVAL;
 158         }
 159
 160         mutex_init(&bus->mdio_lock);
 161
 162         if (bus->reset)
 163                 bus->reset(bus);
 164
 165         for (i = 0; i < PHY_MAX_ADDR; i++) {
 166                 if ((bus->phy_mask & (1 << i)) == 0) {
 167                         struct phy_device *phydev;
 168
 169                         phydev = mdiobus_scan(bus, i);
 170                         if (IS_ERR(phydev)) {
 171                                 err = PTR_ERR(phydev);
 172                                 goto error;
 173                         }
 174                 }
 175         }
 176
 177         bus->state = MDIOBUS_REGISTERED;
 178         pr_info("%s: probed\n", bus->name);
 179         return 0;
 180
 181 error:
 182         while (--i >= 0) {
 183                 if (bus->phy_map[i])
 184                         device_unregister(&bus->phy_map[i]->dev);
 185         }
 186         device_del(&bus->dev);
 187         return err;
 188 }
 189 EXPORT_SYMBOL(mdiobus_register);
 190
 191 void mdiobus_unregister(struct mii_bus *bus)
 192 {
 193         int i;
 194
 195         BUG_ON(bus->state != MDIOBUS_REGISTERED);
 196         bus->state = MDIOBUS_UNREGISTERED;
 197
 198         device_del(&bus->dev);
 199         for (i = 0; i < PHY_MAX_ADDR; i++) {
 200                 if (bus->phy_map[i])
 201                         device_unregister(&bus->phy_map[i]->dev);
 202                 bus->phy_map[i] = NULL;
 203         }
 204 }
 205 EXPORT_SYMBOL(mdiobus_unregister);
 206
 207 /**
 208  * mdiobus_free - free a struct mii_bus
 209  * @bus: mii_bus to free
 210  *
 211  * This function releases the reference to the underlying device
 212  * object in the mii_bus.  If this is the last reference, the mii_bus
 213  * will be freed.
 214  */
 215 void mdiobus_free(struct mii_bus *bus)
 216 {
 217         /*
 218          * For compatibility with error handling in drivers.
 219          */
 220         if (bus->state == MDIOBUS_ALLOCATED) {
 221                 kfree(bus);
 222                 return;
 223         }
 224
 225         BUG_ON(bus->state != MDIOBUS_UNREGISTERED);
 226         bus->state = MDIOBUS_RELEASED;
 227
 228         put_device(&bus->dev);
 229 }
 230 EXPORT_SYMBOL(mdiobus_free);
 231
 232 struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
 233 {
 234         struct phy_device *phydev;
 235         int err;
 236
 237         phydev = get_phy_device(bus, addr, false);
 238         if (IS_ERR(phydev) || phydev == NULL)
 239                 return phydev;
 240
 241         err = phy_device_register(phydev);
 242         if (err) {
 243                 phy_device_free(phydev);
 244                 return NULL;
 245         }
 246
 247         return phydev;
 248 }
 249 EXPORT_SYMBOL(mdiobus_scan);
 250
 251 /**
 252  * mdiobus_read - Convenience function for reading a given MII mgmt register
 253  * @bus: the mii_bus struct
 254  * @addr: the phy address
 255  * @regnum: register number to read
 256  *
 257  * NOTE: MUST NOT be called from interrupt context,
 258  * because the bus read/write functions may wait for an interrupt
 259  * to conclude the operation.
 260  */
 261 int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
 262 {
 263         int retval;
 264
 265         BUG_ON(in_interrupt());
 266
 267         mutex_lock(&bus->mdio_lock);
 268         retval = bus->read(bus, addr, regnum);
 269         mutex_unlock(&bus->mdio_lock);
 270
 271         return retval;
 272 }
 273 EXPORT_SYMBOL(mdiobus_read);
 274
 275 /**
 276  * mdiobus_write - Convenience function for writing a given MII mgmt register
 277  * @bus: the mii_bus struct
 278  * @addr: the phy address
 279  * @regnum: register number to write
 280  * @val: value to write to @regnum
 281  *
 282  * NOTE: MUST NOT be called from interrupt context,
 283  * because the bus read/write functions may wait for an interrupt
 284  * to conclude the operation.
 285  */
 286 int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
 287 {
 288         int err;
 289
 290         BUG_ON(in_interrupt());
 291
 292         mutex_lock(&bus->mdio_lock);
 293         err = bus->write(bus, addr, regnum, val);
 294         mutex_unlock(&bus->mdio_lock);
 295
 296         return err;
 297 }
 298 EXPORT_SYMBOL(mdiobus_write);
 299
 300 /**
 301  * mdio_bus_match - determine if given PHY driver supports the given PHY device
 302  * @dev: target PHY device
 303  * @drv: given PHY driver
 304  *
 305  * Description: Given a PHY device, and a PHY driver, return 1 if
 306  *   the driver supports the device.  Otherwise, return 0.
 307  */
 308 static int mdio_bus_match(struct device *dev, struct device_driver *drv)
 309 {
 310         struct phy_device *phydev = to_phy_device(dev);
 311         struct phy_driver *phydrv = to_phy_driver(drv);
 312
 313         if (of_driver_match_device(dev, drv))
 314                 return 1;
 315
 316         if (phydrv->match_phy_device)
 317                 return phydrv->match_phy_device(phydev);
 318
 319         return ((phydrv->phy_id & phydrv->phy_id_mask) ==
 320                 (phydev->phy_id & phydrv->phy_id_mask));
 321 }
 322
 323 #ifdef CONFIG_PM
 324
 325 static bool mdio_bus_phy_may_suspend(struct phy_device *phydev)
 326 {
 327         struct device_driver *drv = phydev->dev.driver;
 328         struct phy_driver *phydrv = to_phy_driver(drv);
 329         struct net_device *netdev = phydev->attached_dev;
 330
 331         if (!drv || !phydrv->suspend)
 332                 return false;
 333
 334         /* PHY not attached? May suspend. */
 335         if (!netdev)
 336                 return true;
 337
 338         /*
 339          * Don't suspend PHY if the attched netdev parent may wakeup.
 340          * The parent may point to a PCI device, as in tg3 driver.
 341          */
 342         if (netdev->dev.parent && device_may_wakeup(netdev->dev.parent))
 343                 return false;
 344
 345         /*
 346          * Also don't suspend PHY if the netdev itself may wakeup. This
 347          * is the case for devices w/o underlaying pwr. mgmt. aware bus,
 348          * e.g. SoC devices.
 349          */
 350         if (device_may_wakeup(&netdev->dev))
 351                 return false;
 352
 353         return true;
 354 }
 355
 356 static int mdio_bus_suspend(struct device *dev)
 357 {
 358         struct phy_driver *phydrv = to_phy_driver(dev->driver);
 359         struct phy_device *phydev = to_phy_device(dev);
 360
 361         /*
 362          * We must stop the state machine manually, otherwise it stops out of
 363          * control, possibly with the phydev->lock held. Upon resume, netdev
 364          * may call phy routines that try to grab the same lock, and that may
 365          * lead to a deadlock.
 366          */
 367         if (phydev->attached_dev && phydev->adjust_link)
 368                 phy_stop_machine(phydev);
 369
 370         if (!mdio_bus_phy_may_suspend(phydev))
 371                 return 0;
 372
 373         return phydrv->suspend(phydev);
 374 }
 375
 376 static int mdio_bus_resume(struct device *dev)
 377 {
 378         struct phy_driver *phydrv = to_phy_driver(dev->driver);
 379         struct phy_device *phydev = to_phy_device(dev);
 380         int ret;
 381
 382         if (!mdio_bus_phy_may_suspend(phydev))
 383                 goto no_resume;
 384
 385         ret = phydrv->resume(phydev);
 386         if (ret < 0)
 387                 return ret;
 388
 389 no_resume:
 390         if (phydev->attached_dev && phydev->adjust_link)
 391                 phy_start_machine(phydev, NULL);
 392
 393         return 0;
 394 }
 395
 396 static int mdio_bus_restore(struct device *dev)
 397 {
 398         struct phy_device *phydev = to_phy_device(dev);
 399         struct net_device *netdev = phydev->attached_dev;
 400         int ret;
 401
 402         if (!netdev)
 403                 return 0;
 404
 405         ret = phy_init_hw(phydev);
 406         if (ret < 0)
 407                 return ret;
 408
 409         /* The PHY needs to renegotiate. */
 410         phydev->link = 0;
 411         phydev->state = PHY_UP;
 412
 413         phy_start_machine(phydev, NULL);
 414
 415         return 0;
 416 }
 417
 418 static struct dev_pm_ops mdio_bus_pm_ops = {
 419         .suspend = mdio_bus_suspend,
 420         .resume = mdio_bus_resume,
 421         .freeze = mdio_bus_suspend,
 422         .thaw = mdio_bus_resume,
 423         .restore = mdio_bus_restore,
 424 };
 425
 426 #define MDIO_BUS_PM_OPS (&mdio_bus_pm_ops)
 427
 428 #else
 429
 430 #define MDIO_BUS_PM_OPS NULL
 431
 432 #endif /* CONFIG_PM */
 433
 434 static ssize_t
 435 phy_id_show(struct device *dev, struct device_attribute *attr, char *buf)
 436 {
 437         struct phy_device *phydev = to_phy_device(dev);
 438
 439         return sprintf(buf, "0x%.8lx\n", (unsigned long)phydev->phy_id);
 440 }
 441 static DEVICE_ATTR_RO(phy_id);
 442
 443 static struct attribute *mdio_dev_attrs[] = {
 444         &dev_attr_phy_id.attr,
 445         NULL,
 446 };
 447 ATTRIBUTE_GROUPS(mdio_dev);
 448
 449 struct bus_type mdio_bus_type = {
 450         .name           = "mdio_bus",
 451         .match          = mdio_bus_match,
 452         .pm             = MDIO_BUS_PM_OPS,
 453         .dev_groups     = mdio_dev_groups,
 454 };
 455 EXPORT_SYMBOL(mdio_bus_type);
 456
 457 int __init mdio_bus_init(void)
 458 {
 459         int ret;
 460
 461         ret = class_register(&mdio_bus_class);
 462         if (!ret) {
 463                 ret = bus_register(&mdio_bus_type);
 464                 if (ret)
 465                         class_unregister(&mdio_bus_class);
 466         }
 467
 468         return ret;
 469 }
 470
 471 void mdio_bus_exit(void)
 472 {
 473         class_unregister(&mdio_bus_class);
 474         bus_unregister(&mdio_bus_type);
 475 }