xref: /linux/drivers/net/phy/mdio_bus.c (revision 4949009eb8d40a441dcddcd96e101e77d31cf1b2)
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 /**
42  * mdiobus_alloc_size - allocate a mii_bus structure
43  * @size: extra amount of memory to allocate for private storage.
44  * If non-zero, then bus->priv is points to that memory.
45  *
46  * Description: called by a bus driver to allocate an mii_bus
47  * structure to fill in.
48  */
49 struct mii_bus *mdiobus_alloc_size(size_t size)
50 {
51 	struct mii_bus *bus;
52 	size_t aligned_size = ALIGN(sizeof(*bus), NETDEV_ALIGN);
53 	size_t alloc_size;
54 
55 	/* If we alloc extra space, it should be aligned */
56 	if (size)
57 		alloc_size = aligned_size + size;
58 	else
59 		alloc_size = sizeof(*bus);
60 
61 	bus = kzalloc(alloc_size, GFP_KERNEL);
62 	if (bus) {
63 		bus->state = MDIOBUS_ALLOCATED;
64 		if (size)
65 			bus->priv = (void *)bus + aligned_size;
66 	}
67 
68 	return bus;
69 }
70 EXPORT_SYMBOL(mdiobus_alloc_size);
71 
72 static void _devm_mdiobus_free(struct device *dev, void *res)
73 {
74 	mdiobus_free(*(struct mii_bus **)res);
75 }
76 
77 static int devm_mdiobus_match(struct device *dev, void *res, void *data)
78 {
79 	struct mii_bus **r = res;
80 
81 	if (WARN_ON(!r || !*r))
82 		return 0;
83 
84 	return *r == data;
85 }
86 
87 /**
88  * devm_mdiobus_alloc_size - Resource-managed mdiobus_alloc_size()
89  * @dev:		Device to allocate mii_bus for
90  * @sizeof_priv:	Space to allocate for private structure.
91  *
92  * Managed mdiobus_alloc_size. mii_bus allocated with this function is
93  * automatically freed on driver detach.
94  *
95  * If an mii_bus allocated with this function needs to be freed separately,
96  * devm_mdiobus_free() must be used.
97  *
98  * RETURNS:
99  * Pointer to allocated mii_bus on success, NULL on failure.
100  */
101 struct mii_bus *devm_mdiobus_alloc_size(struct device *dev, int sizeof_priv)
102 {
103 	struct mii_bus **ptr, *bus;
104 
105 	ptr = devres_alloc(_devm_mdiobus_free, sizeof(*ptr), GFP_KERNEL);
106 	if (!ptr)
107 		return NULL;
108 
109 	/* use raw alloc_dr for kmalloc caller tracing */
110 	bus = mdiobus_alloc_size(sizeof_priv);
111 	if (bus) {
112 		*ptr = bus;
113 		devres_add(dev, ptr);
114 	} else {
115 		devres_free(ptr);
116 	}
117 
118 	return bus;
119 }
120 EXPORT_SYMBOL_GPL(devm_mdiobus_alloc_size);
121 
122 /**
123  * devm_mdiobus_free - Resource-managed mdiobus_free()
124  * @dev:		Device this mii_bus belongs to
125  * @bus:		the mii_bus associated with the device
126  *
127  * Free mii_bus allocated with devm_mdiobus_alloc_size().
128  */
129 void devm_mdiobus_free(struct device *dev, struct mii_bus *bus)
130 {
131 	int rc;
132 
133 	rc = devres_release(dev, _devm_mdiobus_free,
134 			    devm_mdiobus_match, bus);
135 	WARN_ON(rc);
136 }
137 EXPORT_SYMBOL_GPL(devm_mdiobus_free);
138 
139 /**
140  * mdiobus_release - mii_bus device release callback
141  * @d: the target struct device that contains the mii_bus
142  *
143  * Description: called when the last reference to an mii_bus is
144  * dropped, to free the underlying memory.
145  */
146 static void mdiobus_release(struct device *d)
147 {
148 	struct mii_bus *bus = to_mii_bus(d);
149 	BUG_ON(bus->state != MDIOBUS_RELEASED &&
150 	       /* for compatibility with error handling in drivers */
151 	       bus->state != MDIOBUS_ALLOCATED);
152 	kfree(bus);
153 }
154 
155 static struct class mdio_bus_class = {
156 	.name		= "mdio_bus",
157 	.dev_release	= mdiobus_release,
158 };
159 
160 #if IS_ENABLED(CONFIG_OF_MDIO)
161 /* Helper function for of_mdio_find_bus */
162 static int of_mdio_bus_match(struct device *dev, const void *mdio_bus_np)
163 {
164 	return dev->of_node == mdio_bus_np;
165 }
166 /**
167  * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
168  * @mdio_bus_np: Pointer to the mii_bus.
169  *
170  * Returns a pointer to the mii_bus, or NULL if none found.
171  *
172  * Because the association of a device_node and mii_bus is made via
173  * of_mdiobus_register(), the mii_bus cannot be found before it is
174  * registered with of_mdiobus_register().
175  *
176  */
177 struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
178 {
179 	struct device *d;
180 
181 	if (!mdio_bus_np)
182 		return NULL;
183 
184 	d = class_find_device(&mdio_bus_class, NULL,  mdio_bus_np,
185 			      of_mdio_bus_match);
186 
187 	return d ? to_mii_bus(d) : NULL;
188 }
189 EXPORT_SYMBOL(of_mdio_find_bus);
190 
191 /* Walk the list of subnodes of a mdio bus and look for a node that matches the
192  * phy's address with its 'reg' property. If found, set the of_node pointer for
193  * the phy. This allows auto-probed pyh devices to be supplied with information
194  * passed in via DT.
195  */
196 static void of_mdiobus_link_phydev(struct mii_bus *mdio,
197 				   struct phy_device *phydev)
198 {
199 	struct device *dev = &phydev->dev;
200 	struct device_node *child;
201 
202 	if (dev->of_node || !mdio->dev.of_node)
203 		return;
204 
205 	for_each_available_child_of_node(mdio->dev.of_node, child) {
206 		int addr;
207 		int ret;
208 
209 		ret = of_property_read_u32(child, "reg", &addr);
210 		if (ret < 0) {
211 			dev_err(dev, "%s has invalid PHY address\n",
212 				child->full_name);
213 			continue;
214 		}
215 
216 		/* A PHY must have a reg property in the range [0-31] */
217 		if (addr >= PHY_MAX_ADDR) {
218 			dev_err(dev, "%s PHY address %i is too large\n",
219 				child->full_name, addr);
220 			continue;
221 		}
222 
223 		if (addr == phydev->addr) {
224 			dev->of_node = child;
225 			return;
226 		}
227 	}
228 }
229 #else /* !IS_ENABLED(CONFIG_OF_MDIO) */
230 static inline void of_mdiobus_link_phydev(struct mii_bus *mdio,
231 					  struct phy_device *phydev)
232 {
233 }
234 #endif
235 
236 /**
237  * mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
238  * @bus: target mii_bus
239  *
240  * Description: Called by a bus driver to bring up all the PHYs
241  *   on a given bus, and attach them to the bus.
242  *
243  * Returns 0 on success or < 0 on error.
244  */
245 int mdiobus_register(struct mii_bus *bus)
246 {
247 	int i, err;
248 
249 	if (NULL == bus || NULL == bus->name ||
250 	    NULL == bus->read || NULL == bus->write)
251 		return -EINVAL;
252 
253 	BUG_ON(bus->state != MDIOBUS_ALLOCATED &&
254 	       bus->state != MDIOBUS_UNREGISTERED);
255 
256 	bus->dev.parent = bus->parent;
257 	bus->dev.class = &mdio_bus_class;
258 	bus->dev.groups = NULL;
259 	dev_set_name(&bus->dev, "%s", bus->id);
260 
261 	err = device_register(&bus->dev);
262 	if (err) {
263 		pr_err("mii_bus %s failed to register\n", bus->id);
264 		put_device(&bus->dev);
265 		return -EINVAL;
266 	}
267 
268 	mutex_init(&bus->mdio_lock);
269 
270 	if (bus->reset)
271 		bus->reset(bus);
272 
273 	for (i = 0; i < PHY_MAX_ADDR; i++) {
274 		if ((bus->phy_mask & (1 << i)) == 0) {
275 			struct phy_device *phydev;
276 
277 			phydev = mdiobus_scan(bus, i);
278 			if (IS_ERR(phydev)) {
279 				err = PTR_ERR(phydev);
280 				goto error;
281 			}
282 		}
283 	}
284 
285 	bus->state = MDIOBUS_REGISTERED;
286 	pr_info("%s: probed\n", bus->name);
287 	return 0;
288 
289 error:
290 	while (--i >= 0) {
291 		if (bus->phy_map[i])
292 			device_unregister(&bus->phy_map[i]->dev);
293 	}
294 	device_del(&bus->dev);
295 	return err;
296 }
297 EXPORT_SYMBOL(mdiobus_register);
298 
299 void mdiobus_unregister(struct mii_bus *bus)
300 {
301 	int i;
302 
303 	BUG_ON(bus->state != MDIOBUS_REGISTERED);
304 	bus->state = MDIOBUS_UNREGISTERED;
305 
306 	device_del(&bus->dev);
307 	for (i = 0; i < PHY_MAX_ADDR; i++) {
308 		if (bus->phy_map[i])
309 			device_unregister(&bus->phy_map[i]->dev);
310 		bus->phy_map[i] = NULL;
311 	}
312 }
313 EXPORT_SYMBOL(mdiobus_unregister);
314 
315 /**
316  * mdiobus_free - free a struct mii_bus
317  * @bus: mii_bus to free
318  *
319  * This function releases the reference to the underlying device
320  * object in the mii_bus.  If this is the last reference, the mii_bus
321  * will be freed.
322  */
323 void mdiobus_free(struct mii_bus *bus)
324 {
325 	/* For compatibility with error handling in drivers. */
326 	if (bus->state == MDIOBUS_ALLOCATED) {
327 		kfree(bus);
328 		return;
329 	}
330 
331 	BUG_ON(bus->state != MDIOBUS_UNREGISTERED);
332 	bus->state = MDIOBUS_RELEASED;
333 
334 	put_device(&bus->dev);
335 }
336 EXPORT_SYMBOL(mdiobus_free);
337 
338 struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
339 {
340 	struct phy_device *phydev;
341 	int err;
342 
343 	phydev = get_phy_device(bus, addr, false);
344 	if (IS_ERR(phydev) || phydev == NULL)
345 		return phydev;
346 
347 	/*
348 	 * For DT, see if the auto-probed phy has a correspoding child
349 	 * in the bus node, and set the of_node pointer in this case.
350 	 */
351 	of_mdiobus_link_phydev(bus, phydev);
352 
353 	err = phy_device_register(phydev);
354 	if (err) {
355 		phy_device_free(phydev);
356 		return NULL;
357 	}
358 
359 	return phydev;
360 }
361 EXPORT_SYMBOL(mdiobus_scan);
362 
363 /**
364  * mdiobus_read - Convenience function for reading a given MII mgmt register
365  * @bus: the mii_bus struct
366  * @addr: the phy address
367  * @regnum: register number to read
368  *
369  * NOTE: MUST NOT be called from interrupt context,
370  * because the bus read/write functions may wait for an interrupt
371  * to conclude the operation.
372  */
373 int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
374 {
375 	int retval;
376 
377 	BUG_ON(in_interrupt());
378 
379 	mutex_lock(&bus->mdio_lock);
380 	retval = bus->read(bus, addr, regnum);
381 	mutex_unlock(&bus->mdio_lock);
382 
383 	return retval;
384 }
385 EXPORT_SYMBOL(mdiobus_read);
386 
387 /**
388  * mdiobus_write - Convenience function for writing a given MII mgmt register
389  * @bus: the mii_bus struct
390  * @addr: the phy address
391  * @regnum: register number to write
392  * @val: value to write to @regnum
393  *
394  * NOTE: MUST NOT be called from interrupt context,
395  * because the bus read/write functions may wait for an interrupt
396  * to conclude the operation.
397  */
398 int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
399 {
400 	int err;
401 
402 	BUG_ON(in_interrupt());
403 
404 	mutex_lock(&bus->mdio_lock);
405 	err = bus->write(bus, addr, regnum, val);
406 	mutex_unlock(&bus->mdio_lock);
407 
408 	return err;
409 }
410 EXPORT_SYMBOL(mdiobus_write);
411 
412 /**
413  * mdio_bus_match - determine if given PHY driver supports the given PHY device
414  * @dev: target PHY device
415  * @drv: given PHY driver
416  *
417  * Description: Given a PHY device, and a PHY driver, return 1 if
418  *   the driver supports the device.  Otherwise, return 0.
419  */
420 static int mdio_bus_match(struct device *dev, struct device_driver *drv)
421 {
422 	struct phy_device *phydev = to_phy_device(dev);
423 	struct phy_driver *phydrv = to_phy_driver(drv);
424 
425 	if (of_driver_match_device(dev, drv))
426 		return 1;
427 
428 	if (phydrv->match_phy_device)
429 		return phydrv->match_phy_device(phydev);
430 
431 	return (phydrv->phy_id & phydrv->phy_id_mask) ==
432 		(phydev->phy_id & phydrv->phy_id_mask);
433 }
434 
435 #ifdef CONFIG_PM
436 
437 static bool mdio_bus_phy_may_suspend(struct phy_device *phydev)
438 {
439 	struct device_driver *drv = phydev->dev.driver;
440 	struct phy_driver *phydrv = to_phy_driver(drv);
441 	struct net_device *netdev = phydev->attached_dev;
442 
443 	if (!drv || !phydrv->suspend)
444 		return false;
445 
446 	/* PHY not attached? May suspend. */
447 	if (!netdev)
448 		return true;
449 
450 	/* Don't suspend PHY if the attched netdev parent may wakeup.
451 	 * The parent may point to a PCI device, as in tg3 driver.
452 	 */
453 	if (netdev->dev.parent && device_may_wakeup(netdev->dev.parent))
454 		return false;
455 
456 	/* Also don't suspend PHY if the netdev itself may wakeup. This
457 	 * is the case for devices w/o underlaying pwr. mgmt. aware bus,
458 	 * e.g. SoC devices.
459 	 */
460 	if (device_may_wakeup(&netdev->dev))
461 		return false;
462 
463 	return true;
464 }
465 
466 static int mdio_bus_suspend(struct device *dev)
467 {
468 	struct phy_driver *phydrv = to_phy_driver(dev->driver);
469 	struct phy_device *phydev = to_phy_device(dev);
470 
471 	/* We must stop the state machine manually, otherwise it stops out of
472 	 * control, possibly with the phydev->lock held. Upon resume, netdev
473 	 * may call phy routines that try to grab the same lock, and that may
474 	 * lead to a deadlock.
475 	 */
476 	if (phydev->attached_dev && phydev->adjust_link)
477 		phy_stop_machine(phydev);
478 
479 	if (!mdio_bus_phy_may_suspend(phydev))
480 		return 0;
481 
482 	return phydrv->suspend(phydev);
483 }
484 
485 static int mdio_bus_resume(struct device *dev)
486 {
487 	struct phy_driver *phydrv = to_phy_driver(dev->driver);
488 	struct phy_device *phydev = to_phy_device(dev);
489 	int ret;
490 
491 	if (!mdio_bus_phy_may_suspend(phydev))
492 		goto no_resume;
493 
494 	ret = phydrv->resume(phydev);
495 	if (ret < 0)
496 		return ret;
497 
498 no_resume:
499 	if (phydev->attached_dev && phydev->adjust_link)
500 		phy_start_machine(phydev);
501 
502 	return 0;
503 }
504 
505 static int mdio_bus_restore(struct device *dev)
506 {
507 	struct phy_device *phydev = to_phy_device(dev);
508 	struct net_device *netdev = phydev->attached_dev;
509 	int ret;
510 
511 	if (!netdev)
512 		return 0;
513 
514 	ret = phy_init_hw(phydev);
515 	if (ret < 0)
516 		return ret;
517 
518 	/* The PHY needs to renegotiate. */
519 	phydev->link = 0;
520 	phydev->state = PHY_UP;
521 
522 	phy_start_machine(phydev);
523 
524 	return 0;
525 }
526 
527 static const struct dev_pm_ops mdio_bus_pm_ops = {
528 	.suspend = mdio_bus_suspend,
529 	.resume = mdio_bus_resume,
530 	.freeze = mdio_bus_suspend,
531 	.thaw = mdio_bus_resume,
532 	.restore = mdio_bus_restore,
533 };
534 
535 #define MDIO_BUS_PM_OPS (&mdio_bus_pm_ops)
536 
537 #else
538 
539 #define MDIO_BUS_PM_OPS NULL
540 
541 #endif /* CONFIG_PM */
542 
543 static ssize_t
544 phy_id_show(struct device *dev, struct device_attribute *attr, char *buf)
545 {
546 	struct phy_device *phydev = to_phy_device(dev);
547 
548 	return sprintf(buf, "0x%.8lx\n", (unsigned long)phydev->phy_id);
549 }
550 static DEVICE_ATTR_RO(phy_id);
551 
552 static ssize_t
553 phy_interface_show(struct device *dev, struct device_attribute *attr, char *buf)
554 {
555 	struct phy_device *phydev = to_phy_device(dev);
556 	const char *mode = NULL;
557 
558 	if (phy_is_internal(phydev))
559 		mode = "internal";
560 	else
561 		mode = phy_modes(phydev->interface);
562 
563 	return sprintf(buf, "%s\n", mode);
564 }
565 static DEVICE_ATTR_RO(phy_interface);
566 
567 static ssize_t
568 phy_has_fixups_show(struct device *dev, struct device_attribute *attr, char *buf)
569 {
570 	struct phy_device *phydev = to_phy_device(dev);
571 
572 	return sprintf(buf, "%d\n", phydev->has_fixups);
573 }
574 static DEVICE_ATTR_RO(phy_has_fixups);
575 
576 static struct attribute *mdio_dev_attrs[] = {
577 	&dev_attr_phy_id.attr,
578 	&dev_attr_phy_interface.attr,
579 	&dev_attr_phy_has_fixups.attr,
580 	NULL,
581 };
582 ATTRIBUTE_GROUPS(mdio_dev);
583 
584 struct bus_type mdio_bus_type = {
585 	.name		= "mdio_bus",
586 	.match		= mdio_bus_match,
587 	.pm		= MDIO_BUS_PM_OPS,
588 	.dev_groups	= mdio_dev_groups,
589 };
590 EXPORT_SYMBOL(mdio_bus_type);
591 
592 int __init mdio_bus_init(void)
593 {
594 	int ret;
595 
596 	ret = class_register(&mdio_bus_class);
597 	if (!ret) {
598 		ret = bus_register(&mdio_bus_type);
599 		if (ret)
600 			class_unregister(&mdio_bus_class);
601 	}
602 
603 	return ret;
604 }
605 
606 void mdio_bus_exit(void)
607 {
608 	class_unregister(&mdio_bus_class);
609 	bus_unregister(&mdio_bus_type);
610 }
611