xref: /openbmc/linux/drivers/net/phy/mdio_bus.c (revision abfbd895)
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 reference to the mii_bus, or NULL if none found.  The
171  * embedded struct device will have its reference count incremented,
172  * and this must be put once the bus is finished with.
173  *
174  * Because the association of a device_node and mii_bus is made via
175  * of_mdiobus_register(), the mii_bus cannot be found before it is
176  * registered with of_mdiobus_register().
177  *
178  */
179 struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
180 {
181 	struct device *d;
182 
183 	if (!mdio_bus_np)
184 		return NULL;
185 
186 	d = class_find_device(&mdio_bus_class, NULL,  mdio_bus_np,
187 			      of_mdio_bus_match);
188 
189 	return d ? to_mii_bus(d) : NULL;
190 }
191 EXPORT_SYMBOL(of_mdio_find_bus);
192 
193 /* Walk the list of subnodes of a mdio bus and look for a node that matches the
194  * phy's address with its 'reg' property. If found, set the of_node pointer for
195  * the phy. This allows auto-probed pyh devices to be supplied with information
196  * passed in via DT.
197  */
198 static void of_mdiobus_link_phydev(struct mii_bus *mdio,
199 				   struct phy_device *phydev)
200 {
201 	struct device *dev = &phydev->dev;
202 	struct device_node *child;
203 
204 	if (dev->of_node || !mdio->dev.of_node)
205 		return;
206 
207 	for_each_available_child_of_node(mdio->dev.of_node, child) {
208 		int addr;
209 		int ret;
210 
211 		ret = of_property_read_u32(child, "reg", &addr);
212 		if (ret < 0) {
213 			dev_err(dev, "%s has invalid PHY address\n",
214 				child->full_name);
215 			continue;
216 		}
217 
218 		/* A PHY must have a reg property in the range [0-31] */
219 		if (addr >= PHY_MAX_ADDR) {
220 			dev_err(dev, "%s PHY address %i is too large\n",
221 				child->full_name, addr);
222 			continue;
223 		}
224 
225 		if (addr == phydev->addr) {
226 			dev->of_node = child;
227 			return;
228 		}
229 	}
230 }
231 #else /* !IS_ENABLED(CONFIG_OF_MDIO) */
232 static inline void of_mdiobus_link_phydev(struct mii_bus *mdio,
233 					  struct phy_device *phydev)
234 {
235 }
236 #endif
237 
238 /**
239  * __mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
240  * @bus: target mii_bus
241  * @owner: module containing bus accessor functions
242  *
243  * Description: Called by a bus driver to bring up all the PHYs
244  *   on a given bus, and attach them to the bus. Drivers should use
245  *   mdiobus_register() rather than __mdiobus_register() unless they
246  *   need to pass a specific owner module.
247  *
248  * Returns 0 on success or < 0 on error.
249  */
250 int __mdiobus_register(struct mii_bus *bus, struct module *owner)
251 {
252 	int i, err;
253 
254 	if (NULL == bus || NULL == bus->name ||
255 	    NULL == bus->read || NULL == bus->write)
256 		return -EINVAL;
257 
258 	BUG_ON(bus->state != MDIOBUS_ALLOCATED &&
259 	       bus->state != MDIOBUS_UNREGISTERED);
260 
261 	bus->owner = owner;
262 	bus->dev.parent = bus->parent;
263 	bus->dev.class = &mdio_bus_class;
264 	bus->dev.groups = NULL;
265 	dev_set_name(&bus->dev, "%s", bus->id);
266 
267 	err = device_register(&bus->dev);
268 	if (err) {
269 		pr_err("mii_bus %s failed to register\n", bus->id);
270 		put_device(&bus->dev);
271 		return -EINVAL;
272 	}
273 
274 	mutex_init(&bus->mdio_lock);
275 
276 	if (bus->reset)
277 		bus->reset(bus);
278 
279 	for (i = 0; i < PHY_MAX_ADDR; i++) {
280 		if ((bus->phy_mask & (1 << i)) == 0) {
281 			struct phy_device *phydev;
282 
283 			phydev = mdiobus_scan(bus, i);
284 			if (IS_ERR(phydev)) {
285 				err = PTR_ERR(phydev);
286 				goto error;
287 			}
288 		}
289 	}
290 
291 	bus->state = MDIOBUS_REGISTERED;
292 	pr_info("%s: probed\n", bus->name);
293 	return 0;
294 
295 error:
296 	while (--i >= 0) {
297 		struct phy_device *phydev = bus->phy_map[i];
298 		if (phydev) {
299 			phy_device_remove(phydev);
300 			phy_device_free(phydev);
301 		}
302 	}
303 	device_del(&bus->dev);
304 	return err;
305 }
306 EXPORT_SYMBOL(__mdiobus_register);
307 
308 void mdiobus_unregister(struct mii_bus *bus)
309 {
310 	int i;
311 
312 	BUG_ON(bus->state != MDIOBUS_REGISTERED);
313 	bus->state = MDIOBUS_UNREGISTERED;
314 
315 	for (i = 0; i < PHY_MAX_ADDR; i++) {
316 		struct phy_device *phydev = bus->phy_map[i];
317 		if (phydev) {
318 			phy_device_remove(phydev);
319 			phy_device_free(phydev);
320 		}
321 	}
322 	device_del(&bus->dev);
323 }
324 EXPORT_SYMBOL(mdiobus_unregister);
325 
326 /**
327  * mdiobus_free - free a struct mii_bus
328  * @bus: mii_bus to free
329  *
330  * This function releases the reference to the underlying device
331  * object in the mii_bus.  If this is the last reference, the mii_bus
332  * will be freed.
333  */
334 void mdiobus_free(struct mii_bus *bus)
335 {
336 	/* For compatibility with error handling in drivers. */
337 	if (bus->state == MDIOBUS_ALLOCATED) {
338 		kfree(bus);
339 		return;
340 	}
341 
342 	BUG_ON(bus->state != MDIOBUS_UNREGISTERED);
343 	bus->state = MDIOBUS_RELEASED;
344 
345 	put_device(&bus->dev);
346 }
347 EXPORT_SYMBOL(mdiobus_free);
348 
349 struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
350 {
351 	struct phy_device *phydev;
352 	int err;
353 
354 	phydev = get_phy_device(bus, addr, false);
355 	if (IS_ERR(phydev) || phydev == NULL)
356 		return phydev;
357 
358 	/*
359 	 * For DT, see if the auto-probed phy has a correspoding child
360 	 * in the bus node, and set the of_node pointer in this case.
361 	 */
362 	of_mdiobus_link_phydev(bus, phydev);
363 
364 	err = phy_device_register(phydev);
365 	if (err) {
366 		phy_device_free(phydev);
367 		return NULL;
368 	}
369 
370 	return phydev;
371 }
372 EXPORT_SYMBOL(mdiobus_scan);
373 
374 /**
375  * mdiobus_read_nested - Nested version of the mdiobus_read function
376  * @bus: the mii_bus struct
377  * @addr: the phy address
378  * @regnum: register number to read
379  *
380  * In case of nested MDIO bus access avoid lockdep false positives by
381  * using mutex_lock_nested().
382  *
383  * NOTE: MUST NOT be called from interrupt context,
384  * because the bus read/write functions may wait for an interrupt
385  * to conclude the operation.
386  */
387 int mdiobus_read_nested(struct mii_bus *bus, int addr, u32 regnum)
388 {
389 	int retval;
390 
391 	BUG_ON(in_interrupt());
392 
393 	mutex_lock_nested(&bus->mdio_lock, SINGLE_DEPTH_NESTING);
394 	retval = bus->read(bus, addr, regnum);
395 	mutex_unlock(&bus->mdio_lock);
396 
397 	return retval;
398 }
399 EXPORT_SYMBOL(mdiobus_read_nested);
400 
401 /**
402  * mdiobus_read - Convenience function for reading a given MII mgmt register
403  * @bus: the mii_bus struct
404  * @addr: the phy address
405  * @regnum: register number to read
406  *
407  * NOTE: MUST NOT be called from interrupt context,
408  * because the bus read/write functions may wait for an interrupt
409  * to conclude the operation.
410  */
411 int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
412 {
413 	int retval;
414 
415 	BUG_ON(in_interrupt());
416 
417 	mutex_lock(&bus->mdio_lock);
418 	retval = bus->read(bus, addr, regnum);
419 	mutex_unlock(&bus->mdio_lock);
420 
421 	return retval;
422 }
423 EXPORT_SYMBOL(mdiobus_read);
424 
425 /**
426  * mdiobus_write_nested - Nested version of the mdiobus_write function
427  * @bus: the mii_bus struct
428  * @addr: the phy address
429  * @regnum: register number to write
430  * @val: value to write to @regnum
431  *
432  * In case of nested MDIO bus access avoid lockdep false positives by
433  * using mutex_lock_nested().
434  *
435  * NOTE: MUST NOT be called from interrupt context,
436  * because the bus read/write functions may wait for an interrupt
437  * to conclude the operation.
438  */
439 int mdiobus_write_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val)
440 {
441 	int err;
442 
443 	BUG_ON(in_interrupt());
444 
445 	mutex_lock_nested(&bus->mdio_lock, SINGLE_DEPTH_NESTING);
446 	err = bus->write(bus, addr, regnum, val);
447 	mutex_unlock(&bus->mdio_lock);
448 
449 	return err;
450 }
451 EXPORT_SYMBOL(mdiobus_write_nested);
452 
453 /**
454  * mdiobus_write - Convenience function for writing a given MII mgmt register
455  * @bus: the mii_bus struct
456  * @addr: the phy address
457  * @regnum: register number to write
458  * @val: value to write to @regnum
459  *
460  * NOTE: MUST NOT be called from interrupt context,
461  * because the bus read/write functions may wait for an interrupt
462  * to conclude the operation.
463  */
464 int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
465 {
466 	int err;
467 
468 	BUG_ON(in_interrupt());
469 
470 	mutex_lock(&bus->mdio_lock);
471 	err = bus->write(bus, addr, regnum, val);
472 	mutex_unlock(&bus->mdio_lock);
473 
474 	return err;
475 }
476 EXPORT_SYMBOL(mdiobus_write);
477 
478 /**
479  * mdio_bus_match - determine if given PHY driver supports the given PHY device
480  * @dev: target PHY device
481  * @drv: given PHY driver
482  *
483  * Description: Given a PHY device, and a PHY driver, return 1 if
484  *   the driver supports the device.  Otherwise, return 0.
485  */
486 static int mdio_bus_match(struct device *dev, struct device_driver *drv)
487 {
488 	struct phy_device *phydev = to_phy_device(dev);
489 	struct phy_driver *phydrv = to_phy_driver(drv);
490 	const int num_ids = ARRAY_SIZE(phydev->c45_ids.device_ids);
491 	int i;
492 
493 	if (of_driver_match_device(dev, drv))
494 		return 1;
495 
496 	if (phydrv->match_phy_device)
497 		return phydrv->match_phy_device(phydev);
498 
499 	if (phydev->is_c45) {
500 		for (i = 1; i < num_ids; i++) {
501 			if (!(phydev->c45_ids.devices_in_package & (1 << i)))
502 				continue;
503 
504 			if ((phydrv->phy_id & phydrv->phy_id_mask) ==
505 			    (phydev->c45_ids.device_ids[i] &
506 			     phydrv->phy_id_mask))
507 				return 1;
508 		}
509 		return 0;
510 	} else {
511 		return (phydrv->phy_id & phydrv->phy_id_mask) ==
512 			(phydev->phy_id & phydrv->phy_id_mask);
513 	}
514 }
515 
516 #ifdef CONFIG_PM
517 
518 static bool mdio_bus_phy_may_suspend(struct phy_device *phydev)
519 {
520 	struct device_driver *drv = phydev->dev.driver;
521 	struct phy_driver *phydrv = to_phy_driver(drv);
522 	struct net_device *netdev = phydev->attached_dev;
523 
524 	if (!drv || !phydrv->suspend)
525 		return false;
526 
527 	/* PHY not attached? May suspend if the PHY has not already been
528 	 * suspended as part of a prior call to phy_disconnect() ->
529 	 * phy_detach() -> phy_suspend() because the parent netdev might be the
530 	 * MDIO bus driver and clock gated at this point.
531 	 */
532 	if (!netdev)
533 		return !phydev->suspended;
534 
535 	/* Don't suspend PHY if the attched netdev parent may wakeup.
536 	 * The parent may point to a PCI device, as in tg3 driver.
537 	 */
538 	if (netdev->dev.parent && device_may_wakeup(netdev->dev.parent))
539 		return false;
540 
541 	/* Also don't suspend PHY if the netdev itself may wakeup. This
542 	 * is the case for devices w/o underlaying pwr. mgmt. aware bus,
543 	 * e.g. SoC devices.
544 	 */
545 	if (device_may_wakeup(&netdev->dev))
546 		return false;
547 
548 	return true;
549 }
550 
551 static int mdio_bus_suspend(struct device *dev)
552 {
553 	struct phy_device *phydev = to_phy_device(dev);
554 
555 	/* We must stop the state machine manually, otherwise it stops out of
556 	 * control, possibly with the phydev->lock held. Upon resume, netdev
557 	 * may call phy routines that try to grab the same lock, and that may
558 	 * lead to a deadlock.
559 	 */
560 	if (phydev->attached_dev && phydev->adjust_link)
561 		phy_stop_machine(phydev);
562 
563 	if (!mdio_bus_phy_may_suspend(phydev))
564 		return 0;
565 
566 	return phy_suspend(phydev);
567 }
568 
569 static int mdio_bus_resume(struct device *dev)
570 {
571 	struct phy_device *phydev = to_phy_device(dev);
572 	int ret;
573 
574 	if (!mdio_bus_phy_may_suspend(phydev))
575 		goto no_resume;
576 
577 	ret = phy_resume(phydev);
578 	if (ret < 0)
579 		return ret;
580 
581 no_resume:
582 	if (phydev->attached_dev && phydev->adjust_link)
583 		phy_start_machine(phydev);
584 
585 	return 0;
586 }
587 
588 static int mdio_bus_restore(struct device *dev)
589 {
590 	struct phy_device *phydev = to_phy_device(dev);
591 	struct net_device *netdev = phydev->attached_dev;
592 	int ret;
593 
594 	if (!netdev)
595 		return 0;
596 
597 	ret = phy_init_hw(phydev);
598 	if (ret < 0)
599 		return ret;
600 
601 	/* The PHY needs to renegotiate. */
602 	phydev->link = 0;
603 	phydev->state = PHY_UP;
604 
605 	phy_start_machine(phydev);
606 
607 	return 0;
608 }
609 
610 static const struct dev_pm_ops mdio_bus_pm_ops = {
611 	.suspend = mdio_bus_suspend,
612 	.resume = mdio_bus_resume,
613 	.freeze = mdio_bus_suspend,
614 	.thaw = mdio_bus_resume,
615 	.restore = mdio_bus_restore,
616 };
617 
618 #define MDIO_BUS_PM_OPS (&mdio_bus_pm_ops)
619 
620 #else
621 
622 #define MDIO_BUS_PM_OPS NULL
623 
624 #endif /* CONFIG_PM */
625 
626 static ssize_t
627 phy_id_show(struct device *dev, struct device_attribute *attr, char *buf)
628 {
629 	struct phy_device *phydev = to_phy_device(dev);
630 
631 	return sprintf(buf, "0x%.8lx\n", (unsigned long)phydev->phy_id);
632 }
633 static DEVICE_ATTR_RO(phy_id);
634 
635 static ssize_t
636 phy_interface_show(struct device *dev, struct device_attribute *attr, char *buf)
637 {
638 	struct phy_device *phydev = to_phy_device(dev);
639 	const char *mode = NULL;
640 
641 	if (phy_is_internal(phydev))
642 		mode = "internal";
643 	else
644 		mode = phy_modes(phydev->interface);
645 
646 	return sprintf(buf, "%s\n", mode);
647 }
648 static DEVICE_ATTR_RO(phy_interface);
649 
650 static ssize_t
651 phy_has_fixups_show(struct device *dev, struct device_attribute *attr, char *buf)
652 {
653 	struct phy_device *phydev = to_phy_device(dev);
654 
655 	return sprintf(buf, "%d\n", phydev->has_fixups);
656 }
657 static DEVICE_ATTR_RO(phy_has_fixups);
658 
659 static struct attribute *mdio_dev_attrs[] = {
660 	&dev_attr_phy_id.attr,
661 	&dev_attr_phy_interface.attr,
662 	&dev_attr_phy_has_fixups.attr,
663 	NULL,
664 };
665 ATTRIBUTE_GROUPS(mdio_dev);
666 
667 struct bus_type mdio_bus_type = {
668 	.name		= "mdio_bus",
669 	.match		= mdio_bus_match,
670 	.pm		= MDIO_BUS_PM_OPS,
671 	.dev_groups	= mdio_dev_groups,
672 };
673 EXPORT_SYMBOL(mdio_bus_type);
674 
675 int __init mdio_bus_init(void)
676 {
677 	int ret;
678 
679 	ret = class_register(&mdio_bus_class);
680 	if (!ret) {
681 		ret = bus_register(&mdio_bus_type);
682 		if (ret)
683 			class_unregister(&mdio_bus_class);
684 	}
685 
686 	return ret;
687 }
688 
689 void mdio_bus_exit(void)
690 {
691 	class_unregister(&mdio_bus_class);
692 	bus_unregister(&mdio_bus_type);
693 }
694