xref: /linux/drivers/net/phy/mdio_bus.c (revision 6ae67f115986734bc24dfed5cee1daafb5351623)
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/device.h>
12 #include <linux/errno.h>
13 #include <linux/etherdevice.h>
14 #include <linux/ethtool.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/init.h>
17 #include <linux/io.h>
18 #include <linux/kernel.h>
19 #include <linux/mii.h>
20 #include <linux/mm.h>
21 #include <linux/module.h>
22 #include <linux/netdevice.h>
23 #include <linux/of_device.h>
24 #include <linux/of_mdio.h>
25 #include <linux/phy.h>
26 #include <linux/reset.h>
27 #include <linux/slab.h>
28 #include <linux/spinlock.h>
29 #include <linux/string.h>
30 #include <linux/uaccess.h>
31 #include <linux/unistd.h>
32 #include "mdio-private.h"
33 
34 #define CREATE_TRACE_POINTS
35 #include <trace/events/mdio.h>
36 
37 int mdiobus_register_device(struct mdio_device *mdiodev)
38 {
39 	int err;
40 
41 	if (mdiodev->bus->mdio_map[mdiodev->addr])
42 		return -EBUSY;
43 
44 	if (mdiodev->flags & MDIO_DEVICE_FLAG_PHY) {
45 		err = mdio_device_register_reset(mdiodev);
46 		if (err)
47 			return err;
48 
49 		/* Assert the reset signal */
50 		mdio_device_reset(mdiodev, 1);
51 	}
52 
53 	mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
54 
55 	return 0;
56 }
57 EXPORT_SYMBOL(mdiobus_register_device);
58 
59 int mdiobus_unregister_device(struct mdio_device *mdiodev)
60 {
61 	if (mdiodev->bus->mdio_map[mdiodev->addr] != mdiodev)
62 		return -EINVAL;
63 
64 	mdio_device_unregister_reset(mdiodev);
65 
66 	mdiodev->bus->mdio_map[mdiodev->addr] = NULL;
67 
68 	return 0;
69 }
70 EXPORT_SYMBOL(mdiobus_unregister_device);
71 
72 static struct mdio_device *mdiobus_find_device(struct mii_bus *bus, int addr)
73 {
74 	bool addr_valid = addr >= 0 && addr < ARRAY_SIZE(bus->mdio_map);
75 
76 	if (WARN_ONCE(!addr_valid, "addr %d out of range\n", addr))
77 		return NULL;
78 
79 	return bus->mdio_map[addr];
80 }
81 
82 struct phy_device *mdiobus_get_phy(struct mii_bus *bus, int addr)
83 {
84 	struct mdio_device *mdiodev;
85 
86 	mdiodev = mdiobus_find_device(bus, addr);
87 	if (!mdiodev)
88 		return NULL;
89 
90 	if (!(mdiodev->flags & MDIO_DEVICE_FLAG_PHY))
91 		return NULL;
92 
93 	return container_of(mdiodev, struct phy_device, mdio);
94 }
95 EXPORT_SYMBOL(mdiobus_get_phy);
96 
97 bool mdiobus_is_registered_device(struct mii_bus *bus, int addr)
98 {
99 	return mdiobus_find_device(bus, addr) != NULL;
100 }
101 EXPORT_SYMBOL(mdiobus_is_registered_device);
102 
103 /**
104  * mdiobus_release - mii_bus device release callback
105  * @d: the target struct device that contains the mii_bus
106  *
107  * Description: called when the last reference to an mii_bus is
108  * dropped, to free the underlying memory.
109  */
110 static void mdiobus_release(struct device *d)
111 {
112 	struct mii_bus *bus = to_mii_bus(d);
113 
114 	WARN(bus->state != MDIOBUS_RELEASED &&
115 	     /* for compatibility with error handling in drivers */
116 	     bus->state != MDIOBUS_ALLOCATED,
117 	     "%s: not in RELEASED or ALLOCATED state\n",
118 	     bus->id);
119 
120 	if (bus->state == MDIOBUS_RELEASED)
121 		fwnode_handle_put(dev_fwnode(d));
122 
123 	kfree(bus);
124 }
125 
126 struct mdio_bus_stat_attr {
127 	int addr;
128 	unsigned int field_offset;
129 };
130 
131 static u64 mdio_bus_get_stat(struct mdio_bus_stats *s, unsigned int offset)
132 {
133 	const char *p = (const char *)s + offset;
134 	unsigned int start;
135 	u64 val = 0;
136 
137 	do {
138 		start = u64_stats_fetch_begin(&s->syncp);
139 		val = u64_stats_read((const u64_stats_t *)p);
140 	} while (u64_stats_fetch_retry(&s->syncp, start));
141 
142 	return val;
143 }
144 
145 static u64 mdio_bus_get_global_stat(struct mii_bus *bus, unsigned int offset)
146 {
147 	unsigned int i;
148 	u64 val = 0;
149 
150 	for (i = 0; i < PHY_MAX_ADDR; i++)
151 		val += mdio_bus_get_stat(&bus->stats[i], offset);
152 
153 	return val;
154 }
155 
156 static ssize_t mdio_bus_stat_field_show(struct device *dev,
157 					struct device_attribute *attr,
158 					char *buf)
159 {
160 	struct mii_bus *bus = to_mii_bus(dev);
161 	struct mdio_bus_stat_attr *sattr;
162 	struct dev_ext_attribute *eattr;
163 	u64 val;
164 
165 	eattr = container_of(attr, struct dev_ext_attribute, attr);
166 	sattr = eattr->var;
167 
168 	if (sattr->addr < 0)
169 		val = mdio_bus_get_global_stat(bus, sattr->field_offset);
170 	else
171 		val = mdio_bus_get_stat(&bus->stats[sattr->addr],
172 					sattr->field_offset);
173 
174 	return sysfs_emit(buf, "%llu\n", val);
175 }
176 
177 static ssize_t mdio_bus_device_stat_field_show(struct device *dev,
178 					       struct device_attribute *attr,
179 					       char *buf)
180 {
181 	struct mdio_device *mdiodev = to_mdio_device(dev);
182 	struct mii_bus *bus = mdiodev->bus;
183 	struct mdio_bus_stat_attr *sattr;
184 	struct dev_ext_attribute *eattr;
185 	int addr = mdiodev->addr;
186 	u64 val;
187 
188 	eattr = container_of(attr, struct dev_ext_attribute, attr);
189 	sattr = eattr->var;
190 
191 	val = mdio_bus_get_stat(&bus->stats[addr], sattr->field_offset);
192 
193 	return sysfs_emit(buf, "%llu\n", val);
194 }
195 
196 #define MDIO_BUS_STATS_ATTR_DECL(field, file)				\
197 static struct dev_ext_attribute dev_attr_mdio_bus_##field = {		\
198 	.attr = { .attr = { .name = file, .mode = 0444 },		\
199 		     .show = mdio_bus_stat_field_show,			\
200 	},								\
201 	.var = &((struct mdio_bus_stat_attr) {				\
202 		-1, offsetof(struct mdio_bus_stats, field)		\
203 	}),								\
204 };									\
205 static struct dev_ext_attribute dev_attr_mdio_bus_device_##field = {	\
206 	.attr = { .attr = { .name = file, .mode = 0444 },		\
207 		     .show = mdio_bus_device_stat_field_show,		\
208 	},								\
209 	.var = &((struct mdio_bus_stat_attr) {				\
210 		-1, offsetof(struct mdio_bus_stats, field)		\
211 	}),								\
212 };
213 
214 #define MDIO_BUS_STATS_ATTR(field)					\
215 	MDIO_BUS_STATS_ATTR_DECL(field, __stringify(field))
216 
217 MDIO_BUS_STATS_ATTR(transfers);
218 MDIO_BUS_STATS_ATTR(errors);
219 MDIO_BUS_STATS_ATTR(writes);
220 MDIO_BUS_STATS_ATTR(reads);
221 
222 #define MDIO_BUS_STATS_ADDR_ATTR_DECL(field, addr, file)		\
223 static struct dev_ext_attribute dev_attr_mdio_bus_addr_##field##_##addr = { \
224 	.attr = { .attr = { .name = file, .mode = 0444 },		\
225 		     .show = mdio_bus_stat_field_show,			\
226 	},								\
227 	.var = &((struct mdio_bus_stat_attr) {				\
228 		addr, offsetof(struct mdio_bus_stats, field)		\
229 	}),								\
230 }
231 
232 #define MDIO_BUS_STATS_ADDR_ATTR(field, addr)				\
233 	MDIO_BUS_STATS_ADDR_ATTR_DECL(field, addr,			\
234 				 __stringify(field) "_" __stringify(addr))
235 
236 #define MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(addr)			\
237 	MDIO_BUS_STATS_ADDR_ATTR(transfers, addr);			\
238 	MDIO_BUS_STATS_ADDR_ATTR(errors, addr);				\
239 	MDIO_BUS_STATS_ADDR_ATTR(writes, addr);				\
240 	MDIO_BUS_STATS_ADDR_ATTR(reads, addr)				\
241 
242 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(0);
243 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(1);
244 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(2);
245 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(3);
246 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(4);
247 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(5);
248 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(6);
249 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(7);
250 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(8);
251 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(9);
252 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(10);
253 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(11);
254 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(12);
255 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(13);
256 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(14);
257 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(15);
258 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(16);
259 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(17);
260 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(18);
261 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(19);
262 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(20);
263 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(21);
264 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(22);
265 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(23);
266 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(24);
267 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(25);
268 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(26);
269 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(27);
270 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(28);
271 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(29);
272 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(30);
273 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(31);
274 
275 #define MDIO_BUS_STATS_ADDR_ATTR_GROUP(addr)				\
276 	&dev_attr_mdio_bus_addr_transfers_##addr.attr.attr,		\
277 	&dev_attr_mdio_bus_addr_errors_##addr.attr.attr,		\
278 	&dev_attr_mdio_bus_addr_writes_##addr.attr.attr,		\
279 	&dev_attr_mdio_bus_addr_reads_##addr.attr.attr			\
280 
281 static struct attribute *mdio_bus_statistics_attrs[] = {
282 	&dev_attr_mdio_bus_transfers.attr.attr,
283 	&dev_attr_mdio_bus_errors.attr.attr,
284 	&dev_attr_mdio_bus_writes.attr.attr,
285 	&dev_attr_mdio_bus_reads.attr.attr,
286 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(0),
287 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(1),
288 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(2),
289 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(3),
290 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(4),
291 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(5),
292 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(6),
293 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(7),
294 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(8),
295 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(9),
296 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(10),
297 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(11),
298 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(12),
299 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(13),
300 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(14),
301 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(15),
302 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(16),
303 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(17),
304 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(18),
305 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(19),
306 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(20),
307 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(21),
308 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(22),
309 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(23),
310 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(24),
311 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(25),
312 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(26),
313 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(27),
314 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(28),
315 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(29),
316 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(30),
317 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(31),
318 	NULL,
319 };
320 
321 static const struct attribute_group mdio_bus_statistics_group = {
322 	.name	= "statistics",
323 	.attrs	= mdio_bus_statistics_attrs,
324 };
325 
326 static const struct attribute_group *mdio_bus_groups[] = {
327 	&mdio_bus_statistics_group,
328 	NULL,
329 };
330 
331 const struct class mdio_bus_class = {
332 	.name		= "mdio_bus",
333 	.dev_release	= mdiobus_release,
334 	.dev_groups	= mdio_bus_groups,
335 };
336 EXPORT_SYMBOL_GPL(mdio_bus_class);
337 
338 /**
339  * mdio_find_bus - Given the name of a mdiobus, find the mii_bus.
340  * @mdio_name: The name of a mdiobus.
341  *
342  * Returns a reference to the mii_bus, or NULL if none found.  The
343  * embedded struct device will have its reference count incremented,
344  * and this must be put_deviced'ed once the bus is finished with.
345  */
346 struct mii_bus *mdio_find_bus(const char *mdio_name)
347 {
348 	struct device *d;
349 
350 	d = class_find_device_by_name(&mdio_bus_class, mdio_name);
351 	return d ? to_mii_bus(d) : NULL;
352 }
353 EXPORT_SYMBOL(mdio_find_bus);
354 
355 #if IS_ENABLED(CONFIG_OF_MDIO)
356 /**
357  * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
358  * @mdio_bus_np: Pointer to the mii_bus.
359  *
360  * Returns a reference to the mii_bus, or NULL if none found.  The
361  * embedded struct device will have its reference count incremented,
362  * and this must be put once the bus is finished with.
363  *
364  * Because the association of a device_node and mii_bus is made via
365  * of_mdiobus_register(), the mii_bus cannot be found before it is
366  * registered with of_mdiobus_register().
367  *
368  */
369 struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
370 {
371 	struct device *d;
372 
373 	if (!mdio_bus_np)
374 		return NULL;
375 
376 	d = class_find_device_by_of_node(&mdio_bus_class, mdio_bus_np);
377 	return d ? to_mii_bus(d) : NULL;
378 }
379 EXPORT_SYMBOL(of_mdio_find_bus);
380 #endif
381 
382 static void mdiobus_stats_acct(struct mdio_bus_stats *stats, bool op, int ret)
383 {
384 	preempt_disable();
385 	u64_stats_update_begin(&stats->syncp);
386 
387 	u64_stats_inc(&stats->transfers);
388 	if (ret < 0) {
389 		u64_stats_inc(&stats->errors);
390 		goto out;
391 	}
392 
393 	if (op)
394 		u64_stats_inc(&stats->reads);
395 	else
396 		u64_stats_inc(&stats->writes);
397 out:
398 	u64_stats_update_end(&stats->syncp);
399 	preempt_enable();
400 }
401 
402 /**
403  * __mdiobus_read - Unlocked version of the mdiobus_read function
404  * @bus: the mii_bus struct
405  * @addr: the phy address
406  * @regnum: register number to read
407  *
408  * Read a MDIO bus register. Caller must hold the mdio bus lock.
409  *
410  * NOTE: MUST NOT be called from interrupt context.
411  */
412 int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
413 {
414 	int retval;
415 
416 	lockdep_assert_held_once(&bus->mdio_lock);
417 
418 	if (addr >= PHY_MAX_ADDR)
419 		return -ENXIO;
420 
421 	if (bus->read)
422 		retval = bus->read(bus, addr, regnum);
423 	else
424 		retval = -EOPNOTSUPP;
425 
426 	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
427 	mdiobus_stats_acct(&bus->stats[addr], true, retval);
428 
429 	return retval;
430 }
431 EXPORT_SYMBOL(__mdiobus_read);
432 
433 /**
434  * __mdiobus_write - Unlocked version of the mdiobus_write function
435  * @bus: the mii_bus struct
436  * @addr: the phy address
437  * @regnum: register number to write
438  * @val: value to write to @regnum
439  *
440  * Write a MDIO bus register. Caller must hold the mdio bus lock.
441  *
442  * NOTE: MUST NOT be called from interrupt context.
443  */
444 int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
445 {
446 	int err;
447 
448 	lockdep_assert_held_once(&bus->mdio_lock);
449 
450 	if (addr >= PHY_MAX_ADDR)
451 		return -ENXIO;
452 
453 	if (bus->write)
454 		err = bus->write(bus, addr, regnum, val);
455 	else
456 		err = -EOPNOTSUPP;
457 
458 	trace_mdio_access(bus, 0, addr, regnum, val, err);
459 	mdiobus_stats_acct(&bus->stats[addr], false, err);
460 
461 	return err;
462 }
463 EXPORT_SYMBOL(__mdiobus_write);
464 
465 /**
466  * __mdiobus_modify_changed - Unlocked version of the mdiobus_modify function
467  * @bus: the mii_bus struct
468  * @addr: the phy address
469  * @regnum: register number to modify
470  * @mask: bit mask of bits to clear
471  * @set: bit mask of bits to set
472  *
473  * Read, modify, and if any change, write the register value back to the
474  * device. Any error returns a negative number.
475  *
476  * NOTE: MUST NOT be called from interrupt context.
477  */
478 int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
479 			     u16 mask, u16 set)
480 {
481 	int new, ret;
482 
483 	ret = __mdiobus_read(bus, addr, regnum);
484 	if (ret < 0)
485 		return ret;
486 
487 	new = (ret & ~mask) | set;
488 	if (new == ret)
489 		return 0;
490 
491 	ret = __mdiobus_write(bus, addr, regnum, new);
492 
493 	return ret < 0 ? ret : 1;
494 }
495 EXPORT_SYMBOL_GPL(__mdiobus_modify_changed);
496 
497 /**
498  * __mdiobus_c45_read - Unlocked version of the mdiobus_c45_read function
499  * @bus: the mii_bus struct
500  * @addr: the phy address
501  * @devad: device address to read
502  * @regnum: register number to read
503  *
504  * Read a MDIO bus register. Caller must hold the mdio bus lock.
505  *
506  * NOTE: MUST NOT be called from interrupt context.
507  */
508 int __mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum)
509 {
510 	int retval;
511 
512 	lockdep_assert_held_once(&bus->mdio_lock);
513 
514 	if (addr >= PHY_MAX_ADDR)
515 		return -ENXIO;
516 
517 	if (bus->read_c45)
518 		retval = bus->read_c45(bus, addr, devad, regnum);
519 	else
520 		retval = -EOPNOTSUPP;
521 
522 	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
523 	mdiobus_stats_acct(&bus->stats[addr], true, retval);
524 
525 	return retval;
526 }
527 EXPORT_SYMBOL(__mdiobus_c45_read);
528 
529 /**
530  * __mdiobus_c45_write - Unlocked version of the mdiobus_write function
531  * @bus: the mii_bus struct
532  * @addr: the phy address
533  * @devad: device address to read
534  * @regnum: register number to write
535  * @val: value to write to @regnum
536  *
537  * Write a MDIO bus register. Caller must hold the mdio bus lock.
538  *
539  * NOTE: MUST NOT be called from interrupt context.
540  */
541 int __mdiobus_c45_write(struct mii_bus *bus, int addr, int devad, u32 regnum,
542 			u16 val)
543 {
544 	int err;
545 
546 	lockdep_assert_held_once(&bus->mdio_lock);
547 
548 	if (addr >= PHY_MAX_ADDR)
549 		return -ENXIO;
550 
551 	if (bus->write_c45)
552 		err = bus->write_c45(bus, addr, devad, regnum, val);
553 	else
554 		err = -EOPNOTSUPP;
555 
556 	trace_mdio_access(bus, 0, addr, regnum, val, err);
557 	mdiobus_stats_acct(&bus->stats[addr], false, err);
558 
559 	return err;
560 }
561 EXPORT_SYMBOL(__mdiobus_c45_write);
562 
563 /**
564  * __mdiobus_c45_modify_changed - Unlocked version of the mdiobus_modify function
565  * @bus: the mii_bus struct
566  * @addr: the phy address
567  * @devad: device address to read
568  * @regnum: register number to modify
569  * @mask: bit mask of bits to clear
570  * @set: bit mask of bits to set
571  *
572  * Read, modify, and if any change, write the register value back to the
573  * device. Any error returns a negative number.
574  *
575  * NOTE: MUST NOT be called from interrupt context.
576  */
577 static int __mdiobus_c45_modify_changed(struct mii_bus *bus, int addr,
578 					int devad, u32 regnum, u16 mask,
579 					u16 set)
580 {
581 	int new, ret;
582 
583 	ret = __mdiobus_c45_read(bus, addr, devad, regnum);
584 	if (ret < 0)
585 		return ret;
586 
587 	new = (ret & ~mask) | set;
588 	if (new == ret)
589 		return 0;
590 
591 	ret = __mdiobus_c45_write(bus, addr, devad, regnum, new);
592 
593 	return ret < 0 ? ret : 1;
594 }
595 
596 /**
597  * mdiobus_read_nested - Nested version of the mdiobus_read function
598  * @bus: the mii_bus struct
599  * @addr: the phy address
600  * @regnum: register number to read
601  *
602  * In case of nested MDIO bus access avoid lockdep false positives by
603  * using mutex_lock_nested().
604  *
605  * NOTE: MUST NOT be called from interrupt context,
606  * because the bus read/write functions may wait for an interrupt
607  * to conclude the operation.
608  */
609 int mdiobus_read_nested(struct mii_bus *bus, int addr, u32 regnum)
610 {
611 	int retval;
612 
613 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
614 	retval = __mdiobus_read(bus, addr, regnum);
615 	mutex_unlock(&bus->mdio_lock);
616 
617 	return retval;
618 }
619 EXPORT_SYMBOL(mdiobus_read_nested);
620 
621 /**
622  * mdiobus_read - Convenience function for reading a given MII mgmt register
623  * @bus: the mii_bus struct
624  * @addr: the phy address
625  * @regnum: register number to read
626  *
627  * NOTE: MUST NOT be called from interrupt context,
628  * because the bus read/write functions may wait for an interrupt
629  * to conclude the operation.
630  */
631 int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
632 {
633 	int retval;
634 
635 	mutex_lock(&bus->mdio_lock);
636 	retval = __mdiobus_read(bus, addr, regnum);
637 	mutex_unlock(&bus->mdio_lock);
638 
639 	return retval;
640 }
641 EXPORT_SYMBOL(mdiobus_read);
642 
643 /**
644  * mdiobus_c45_read - Convenience function for reading a given MII mgmt register
645  * @bus: the mii_bus struct
646  * @addr: the phy address
647  * @devad: device address to read
648  * @regnum: register number to read
649  *
650  * NOTE: MUST NOT be called from interrupt context,
651  * because the bus read/write functions may wait for an interrupt
652  * to conclude the operation.
653  */
654 int mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum)
655 {
656 	int retval;
657 
658 	mutex_lock(&bus->mdio_lock);
659 	retval = __mdiobus_c45_read(bus, addr, devad, regnum);
660 	mutex_unlock(&bus->mdio_lock);
661 
662 	return retval;
663 }
664 EXPORT_SYMBOL(mdiobus_c45_read);
665 
666 /**
667  * mdiobus_c45_read_nested - Nested version of the mdiobus_c45_read function
668  * @bus: the mii_bus struct
669  * @addr: the phy address
670  * @devad: device address to read
671  * @regnum: register number to read
672  *
673  * In case of nested MDIO bus access avoid lockdep false positives by
674  * using mutex_lock_nested().
675  *
676  * NOTE: MUST NOT be called from interrupt context,
677  * because the bus read/write functions may wait for an interrupt
678  * to conclude the operation.
679  */
680 int mdiobus_c45_read_nested(struct mii_bus *bus, int addr, int devad,
681 			    u32 regnum)
682 {
683 	int retval;
684 
685 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
686 	retval = __mdiobus_c45_read(bus, addr, devad, regnum);
687 	mutex_unlock(&bus->mdio_lock);
688 
689 	return retval;
690 }
691 EXPORT_SYMBOL(mdiobus_c45_read_nested);
692 
693 /**
694  * mdiobus_write_nested - Nested version of the mdiobus_write function
695  * @bus: the mii_bus struct
696  * @addr: the phy address
697  * @regnum: register number to write
698  * @val: value to write to @regnum
699  *
700  * In case of nested MDIO bus access avoid lockdep false positives by
701  * using mutex_lock_nested().
702  *
703  * NOTE: MUST NOT be called from interrupt context,
704  * because the bus read/write functions may wait for an interrupt
705  * to conclude the operation.
706  */
707 int mdiobus_write_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val)
708 {
709 	int err;
710 
711 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
712 	err = __mdiobus_write(bus, addr, regnum, val);
713 	mutex_unlock(&bus->mdio_lock);
714 
715 	return err;
716 }
717 EXPORT_SYMBOL(mdiobus_write_nested);
718 
719 /**
720  * mdiobus_write - Convenience function for writing a given MII mgmt register
721  * @bus: the mii_bus struct
722  * @addr: the phy address
723  * @regnum: register number to write
724  * @val: value to write to @regnum
725  *
726  * NOTE: MUST NOT be called from interrupt context,
727  * because the bus read/write functions may wait for an interrupt
728  * to conclude the operation.
729  */
730 int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
731 {
732 	int err;
733 
734 	mutex_lock(&bus->mdio_lock);
735 	err = __mdiobus_write(bus, addr, regnum, val);
736 	mutex_unlock(&bus->mdio_lock);
737 
738 	return err;
739 }
740 EXPORT_SYMBOL(mdiobus_write);
741 
742 /**
743  * mdiobus_c45_write - Convenience function for writing a given MII mgmt register
744  * @bus: the mii_bus struct
745  * @addr: the phy address
746  * @devad: device address to read
747  * @regnum: register number to write
748  * @val: value to write to @regnum
749  *
750  * NOTE: MUST NOT be called from interrupt context,
751  * because the bus read/write functions may wait for an interrupt
752  * to conclude the operation.
753  */
754 int mdiobus_c45_write(struct mii_bus *bus, int addr, int devad, u32 regnum,
755 		      u16 val)
756 {
757 	int err;
758 
759 	mutex_lock(&bus->mdio_lock);
760 	err = __mdiobus_c45_write(bus, addr, devad, regnum, val);
761 	mutex_unlock(&bus->mdio_lock);
762 
763 	return err;
764 }
765 EXPORT_SYMBOL(mdiobus_c45_write);
766 
767 /**
768  * mdiobus_c45_write_nested - Nested version of the mdiobus_c45_write function
769  * @bus: the mii_bus struct
770  * @addr: the phy address
771  * @devad: device address to read
772  * @regnum: register number to write
773  * @val: value to write to @regnum
774  *
775  * In case of nested MDIO bus access avoid lockdep false positives by
776  * using mutex_lock_nested().
777  *
778  * NOTE: MUST NOT be called from interrupt context,
779  * because the bus read/write functions may wait for an interrupt
780  * to conclude the operation.
781  */
782 int mdiobus_c45_write_nested(struct mii_bus *bus, int addr, int devad,
783 			     u32 regnum, u16 val)
784 {
785 	int err;
786 
787 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
788 	err = __mdiobus_c45_write(bus, addr, devad, regnum, val);
789 	mutex_unlock(&bus->mdio_lock);
790 
791 	return err;
792 }
793 EXPORT_SYMBOL(mdiobus_c45_write_nested);
794 
795 /*
796  * __mdiobus_modify - Convenience function for modifying a given mdio device
797  *	register
798  * @bus: the mii_bus struct
799  * @addr: the phy address
800  * @regnum: register number to write
801  * @mask: bit mask of bits to clear
802  * @set: bit mask of bits to set
803  */
804 int __mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask,
805 		     u16 set)
806 {
807 	int err;
808 
809 	err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
810 
811 	return err < 0 ? err : 0;
812 }
813 EXPORT_SYMBOL_GPL(__mdiobus_modify);
814 
815 /**
816  * mdiobus_modify - Convenience function for modifying a given mdio device
817  *	register
818  * @bus: the mii_bus struct
819  * @addr: the phy address
820  * @regnum: register number to write
821  * @mask: bit mask of bits to clear
822  * @set: bit mask of bits to set
823  */
824 int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask, u16 set)
825 {
826 	int err;
827 
828 	mutex_lock(&bus->mdio_lock);
829 	err = __mdiobus_modify(bus, addr, regnum, mask, set);
830 	mutex_unlock(&bus->mdio_lock);
831 
832 	return err;
833 }
834 EXPORT_SYMBOL_GPL(mdiobus_modify);
835 
836 /**
837  * mdiobus_c45_modify - Convenience function for modifying a given mdio device
838  *	register
839  * @bus: the mii_bus struct
840  * @addr: the phy address
841  * @devad: device address to read
842  * @regnum: register number to write
843  * @mask: bit mask of bits to clear
844  * @set: bit mask of bits to set
845  */
846 int mdiobus_c45_modify(struct mii_bus *bus, int addr, int devad, u32 regnum,
847 		       u16 mask, u16 set)
848 {
849 	int err;
850 
851 	mutex_lock(&bus->mdio_lock);
852 	err = __mdiobus_c45_modify_changed(bus, addr, devad, regnum,
853 					   mask, set);
854 	mutex_unlock(&bus->mdio_lock);
855 
856 	return err < 0 ? err : 0;
857 }
858 EXPORT_SYMBOL_GPL(mdiobus_c45_modify);
859 
860 /**
861  * mdiobus_modify_changed - Convenience function for modifying a given mdio
862  *	device register and returning if it changed
863  * @bus: the mii_bus struct
864  * @addr: the phy address
865  * @regnum: register number to write
866  * @mask: bit mask of bits to clear
867  * @set: bit mask of bits to set
868  */
869 int mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
870 			   u16 mask, u16 set)
871 {
872 	int err;
873 
874 	mutex_lock(&bus->mdio_lock);
875 	err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
876 	mutex_unlock(&bus->mdio_lock);
877 
878 	return err;
879 }
880 EXPORT_SYMBOL_GPL(mdiobus_modify_changed);
881 
882 /**
883  * mdiobus_c45_modify_changed - Convenience function for modifying a given mdio
884  *	device register and returning if it changed
885  * @bus: the mii_bus struct
886  * @addr: the phy address
887  * @devad: device address to read
888  * @regnum: register number to write
889  * @mask: bit mask of bits to clear
890  * @set: bit mask of bits to set
891  */
892 int mdiobus_c45_modify_changed(struct mii_bus *bus, int addr, int devad,
893 			       u32 regnum, u16 mask, u16 set)
894 {
895 	int err;
896 
897 	mutex_lock(&bus->mdio_lock);
898 	err = __mdiobus_c45_modify_changed(bus, addr, devad, regnum, mask, set);
899 	mutex_unlock(&bus->mdio_lock);
900 
901 	return err;
902 }
903 EXPORT_SYMBOL_GPL(mdiobus_c45_modify_changed);
904 
905 /**
906  * mdio_bus_match - determine if given MDIO driver supports the given
907  *		    MDIO device
908  * @dev: target MDIO device
909  * @drv: given MDIO driver
910  *
911  * Description: Given a MDIO device, and a MDIO driver, return 1 if
912  *   the driver supports the device.  Otherwise, return 0. This may
913  *   require calling the devices own match function, since different classes
914  *   of MDIO devices have different match criteria.
915  */
916 static int mdio_bus_match(struct device *dev, const struct device_driver *drv)
917 {
918 	const struct mdio_driver *mdiodrv = to_mdio_driver(drv);
919 	struct mdio_device *mdio = to_mdio_device(dev);
920 
921 	/* Both the driver and device must type-match */
922 	if (!(mdiodrv->mdiodrv.flags & MDIO_DEVICE_IS_PHY) !=
923 	    !(mdio->flags & MDIO_DEVICE_FLAG_PHY))
924 		return 0;
925 
926 	if (of_driver_match_device(dev, drv))
927 		return 1;
928 
929 	if (mdio->bus_match)
930 		return mdio->bus_match(dev, drv);
931 
932 	return 0;
933 }
934 
935 static int mdio_uevent(const struct device *dev, struct kobj_uevent_env *env)
936 {
937 	int rc;
938 
939 	/* Some devices have extra OF data and an OF-style MODALIAS */
940 	rc = of_device_uevent_modalias(dev, env);
941 	if (rc != -ENODEV)
942 		return rc;
943 
944 	return 0;
945 }
946 
947 static struct attribute *mdio_bus_device_statistics_attrs[] = {
948 	&dev_attr_mdio_bus_device_transfers.attr.attr,
949 	&dev_attr_mdio_bus_device_errors.attr.attr,
950 	&dev_attr_mdio_bus_device_writes.attr.attr,
951 	&dev_attr_mdio_bus_device_reads.attr.attr,
952 	NULL,
953 };
954 
955 static const struct attribute_group mdio_bus_device_statistics_group = {
956 	.name	= "statistics",
957 	.attrs	= mdio_bus_device_statistics_attrs,
958 };
959 
960 static const struct attribute_group *mdio_bus_dev_groups[] = {
961 	&mdio_bus_device_statistics_group,
962 	NULL,
963 };
964 
965 const struct bus_type mdio_bus_type = {
966 	.name		= "mdio_bus",
967 	.dev_groups	= mdio_bus_dev_groups,
968 	.match		= mdio_bus_match,
969 	.uevent		= mdio_uevent,
970 };
971 EXPORT_SYMBOL(mdio_bus_type);
972 
973 static int __init mdio_bus_init(void)
974 {
975 	int ret;
976 
977 	ret = class_register(&mdio_bus_class);
978 	if (!ret) {
979 		ret = bus_register(&mdio_bus_type);
980 		if (ret)
981 			class_unregister(&mdio_bus_class);
982 	}
983 
984 	return ret;
985 }
986 
987 static void __exit mdio_bus_exit(void)
988 {
989 	class_unregister(&mdio_bus_class);
990 	bus_unregister(&mdio_bus_type);
991 }
992 
993 subsys_initcall(mdio_bus_init);
994 module_exit(mdio_bus_exit);
995 
996 MODULE_LICENSE("GPL");
997 MODULE_DESCRIPTION("MDIO bus/device layer");
998