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/delay.h>
12 #include <linux/device.h>
13 #include <linux/errno.h>
14 #include <linux/etherdevice.h>
15 #include <linux/ethtool.h>
16 #include <linux/gpio.h>
17 #include <linux/gpio/consumer.h>
18 #include <linux/init.h>
19 #include <linux/interrupt.h>
20 #include <linux/io.h>
21 #include <linux/kernel.h>
22 #include <linux/mii.h>
23 #include <linux/mm.h>
24 #include <linux/module.h>
25 #include <linux/netdevice.h>
26 #include <linux/of_device.h>
27 #include <linux/of_gpio.h>
28 #include <linux/of_mdio.h>
29 #include <linux/phy.h>
30 #include <linux/reset.h>
31 #include <linux/skbuff.h>
32 #include <linux/slab.h>
33 #include <linux/spinlock.h>
34 #include <linux/string.h>
35 #include <linux/uaccess.h>
36 #include <linux/unistd.h>
37 
38 #define CREATE_TRACE_POINTS
39 #include <trace/events/mdio.h>
40 
41 #include "mdio-boardinfo.h"
42 
mdiobus_register_gpiod(struct mdio_device * mdiodev)43 static int mdiobus_register_gpiod(struct mdio_device *mdiodev)
44 {
45 	/* Deassert the optional reset signal */
46 	mdiodev->reset_gpio = gpiod_get_optional(&mdiodev->dev,
47 						 "reset", GPIOD_OUT_LOW);
48 	if (IS_ERR(mdiodev->reset_gpio))
49 		return PTR_ERR(mdiodev->reset_gpio);
50 
51 	if (mdiodev->reset_gpio)
52 		gpiod_set_consumer_name(mdiodev->reset_gpio, "PHY reset");
53 
54 	return 0;
55 }
56 
mdiobus_register_reset(struct mdio_device * mdiodev)57 static int mdiobus_register_reset(struct mdio_device *mdiodev)
58 {
59 	struct reset_control *reset;
60 
61 	reset = reset_control_get_optional_exclusive(&mdiodev->dev, "phy");
62 	if (IS_ERR(reset))
63 		return PTR_ERR(reset);
64 
65 	mdiodev->reset_ctrl = reset;
66 
67 	return 0;
68 }
69 
mdiobus_register_device(struct mdio_device * mdiodev)70 int mdiobus_register_device(struct mdio_device *mdiodev)
71 {
72 	int err;
73 
74 	if (mdiodev->bus->mdio_map[mdiodev->addr])
75 		return -EBUSY;
76 
77 	if (mdiodev->flags & MDIO_DEVICE_FLAG_PHY) {
78 		err = mdiobus_register_gpiod(mdiodev);
79 		if (err)
80 			return err;
81 
82 		err = mdiobus_register_reset(mdiodev);
83 		if (err)
84 			return err;
85 
86 		/* Assert the reset signal */
87 		mdio_device_reset(mdiodev, 1);
88 	}
89 
90 	mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
91 
92 	return 0;
93 }
94 EXPORT_SYMBOL(mdiobus_register_device);
95 
mdiobus_unregister_device(struct mdio_device * mdiodev)96 int mdiobus_unregister_device(struct mdio_device *mdiodev)
97 {
98 	if (mdiodev->bus->mdio_map[mdiodev->addr] != mdiodev)
99 		return -EINVAL;
100 
101 	reset_control_put(mdiodev->reset_ctrl);
102 
103 	mdiodev->bus->mdio_map[mdiodev->addr] = NULL;
104 
105 	return 0;
106 }
107 EXPORT_SYMBOL(mdiobus_unregister_device);
108 
mdiobus_get_phy(struct mii_bus * bus,int addr)109 struct phy_device *mdiobus_get_phy(struct mii_bus *bus, int addr)
110 {
111 	struct mdio_device *mdiodev = bus->mdio_map[addr];
112 
113 	if (!mdiodev)
114 		return NULL;
115 
116 	if (!(mdiodev->flags & MDIO_DEVICE_FLAG_PHY))
117 		return NULL;
118 
119 	return container_of(mdiodev, struct phy_device, mdio);
120 }
121 EXPORT_SYMBOL(mdiobus_get_phy);
122 
mdiobus_is_registered_device(struct mii_bus * bus,int addr)123 bool mdiobus_is_registered_device(struct mii_bus *bus, int addr)
124 {
125 	return bus->mdio_map[addr];
126 }
127 EXPORT_SYMBOL(mdiobus_is_registered_device);
128 
129 /**
130  * mdiobus_alloc_size - allocate a mii_bus structure
131  * @size: extra amount of memory to allocate for private storage.
132  * If non-zero, then bus->priv is points to that memory.
133  *
134  * Description: called by a bus driver to allocate an mii_bus
135  * structure to fill in.
136  */
mdiobus_alloc_size(size_t size)137 struct mii_bus *mdiobus_alloc_size(size_t size)
138 {
139 	struct mii_bus *bus;
140 	size_t aligned_size = ALIGN(sizeof(*bus), NETDEV_ALIGN);
141 	size_t alloc_size;
142 	int i;
143 
144 	/* If we alloc extra space, it should be aligned */
145 	if (size)
146 		alloc_size = aligned_size + size;
147 	else
148 		alloc_size = sizeof(*bus);
149 
150 	bus = kzalloc(alloc_size, GFP_KERNEL);
151 	if (!bus)
152 		return NULL;
153 
154 	bus->state = MDIOBUS_ALLOCATED;
155 	if (size)
156 		bus->priv = (void *)bus + aligned_size;
157 
158 	/* Initialise the interrupts to polling and 64-bit seqcounts */
159 	for (i = 0; i < PHY_MAX_ADDR; i++) {
160 		bus->irq[i] = PHY_POLL;
161 		u64_stats_init(&bus->stats[i].syncp);
162 	}
163 
164 	return bus;
165 }
166 EXPORT_SYMBOL(mdiobus_alloc_size);
167 
168 /**
169  * mdiobus_release - mii_bus device release callback
170  * @d: the target struct device that contains the mii_bus
171  *
172  * Description: called when the last reference to an mii_bus is
173  * dropped, to free the underlying memory.
174  */
mdiobus_release(struct device * d)175 static void mdiobus_release(struct device *d)
176 {
177 	struct mii_bus *bus = to_mii_bus(d);
178 
179 	WARN(bus->state != MDIOBUS_RELEASED &&
180 	     /* for compatibility with error handling in drivers */
181 	     bus->state != MDIOBUS_ALLOCATED,
182 	     "%s: not in RELEASED or ALLOCATED state\n",
183 	     bus->id);
184 	kfree(bus);
185 }
186 
187 struct mdio_bus_stat_attr {
188 	int addr;
189 	unsigned int field_offset;
190 };
191 
mdio_bus_get_stat(struct mdio_bus_stats * s,unsigned int offset)192 static u64 mdio_bus_get_stat(struct mdio_bus_stats *s, unsigned int offset)
193 {
194 	const char *p = (const char *)s + offset;
195 	unsigned int start;
196 	u64 val = 0;
197 
198 	do {
199 		start = u64_stats_fetch_begin(&s->syncp);
200 		val = u64_stats_read((const u64_stats_t *)p);
201 	} while (u64_stats_fetch_retry(&s->syncp, start));
202 
203 	return val;
204 }
205 
mdio_bus_get_global_stat(struct mii_bus * bus,unsigned int offset)206 static u64 mdio_bus_get_global_stat(struct mii_bus *bus, unsigned int offset)
207 {
208 	unsigned int i;
209 	u64 val = 0;
210 
211 	for (i = 0; i < PHY_MAX_ADDR; i++)
212 		val += mdio_bus_get_stat(&bus->stats[i], offset);
213 
214 	return val;
215 }
216 
mdio_bus_stat_field_show(struct device * dev,struct device_attribute * attr,char * buf)217 static ssize_t mdio_bus_stat_field_show(struct device *dev,
218 					struct device_attribute *attr,
219 					char *buf)
220 {
221 	struct mii_bus *bus = to_mii_bus(dev);
222 	struct mdio_bus_stat_attr *sattr;
223 	struct dev_ext_attribute *eattr;
224 	u64 val;
225 
226 	eattr = container_of(attr, struct dev_ext_attribute, attr);
227 	sattr = eattr->var;
228 
229 	if (sattr->addr < 0)
230 		val = mdio_bus_get_global_stat(bus, sattr->field_offset);
231 	else
232 		val = mdio_bus_get_stat(&bus->stats[sattr->addr],
233 					sattr->field_offset);
234 
235 	return sprintf(buf, "%llu\n", val);
236 }
237 
mdio_bus_device_stat_field_show(struct device * dev,struct device_attribute * attr,char * buf)238 static ssize_t mdio_bus_device_stat_field_show(struct device *dev,
239 					       struct device_attribute *attr,
240 					       char *buf)
241 {
242 	struct mdio_device *mdiodev = to_mdio_device(dev);
243 	struct mii_bus *bus = mdiodev->bus;
244 	struct mdio_bus_stat_attr *sattr;
245 	struct dev_ext_attribute *eattr;
246 	int addr = mdiodev->addr;
247 	u64 val;
248 
249 	eattr = container_of(attr, struct dev_ext_attribute, attr);
250 	sattr = eattr->var;
251 
252 	val = mdio_bus_get_stat(&bus->stats[addr], sattr->field_offset);
253 
254 	return sprintf(buf, "%llu\n", val);
255 }
256 
257 #define MDIO_BUS_STATS_ATTR_DECL(field, file)				\
258 static struct dev_ext_attribute dev_attr_mdio_bus_##field = {		\
259 	.attr = { .attr = { .name = file, .mode = 0444 },		\
260 		     .show = mdio_bus_stat_field_show,			\
261 	},								\
262 	.var = &((struct mdio_bus_stat_attr) {				\
263 		-1, offsetof(struct mdio_bus_stats, field)		\
264 	}),								\
265 };									\
266 static struct dev_ext_attribute dev_attr_mdio_bus_device_##field = {	\
267 	.attr = { .attr = { .name = file, .mode = 0444 },		\
268 		     .show = mdio_bus_device_stat_field_show,		\
269 	},								\
270 	.var = &((struct mdio_bus_stat_attr) {				\
271 		-1, offsetof(struct mdio_bus_stats, field)		\
272 	}),								\
273 };
274 
275 #define MDIO_BUS_STATS_ATTR(field)					\
276 	MDIO_BUS_STATS_ATTR_DECL(field, __stringify(field))
277 
278 MDIO_BUS_STATS_ATTR(transfers);
279 MDIO_BUS_STATS_ATTR(errors);
280 MDIO_BUS_STATS_ATTR(writes);
281 MDIO_BUS_STATS_ATTR(reads);
282 
283 #define MDIO_BUS_STATS_ADDR_ATTR_DECL(field, addr, file)		\
284 static struct dev_ext_attribute dev_attr_mdio_bus_addr_##field##_##addr = { \
285 	.attr = { .attr = { .name = file, .mode = 0444 },		\
286 		     .show = mdio_bus_stat_field_show,			\
287 	},								\
288 	.var = &((struct mdio_bus_stat_attr) {				\
289 		addr, offsetof(struct mdio_bus_stats, field)		\
290 	}),								\
291 }
292 
293 #define MDIO_BUS_STATS_ADDR_ATTR(field, addr)				\
294 	MDIO_BUS_STATS_ADDR_ATTR_DECL(field, addr,			\
295 				 __stringify(field) "_" __stringify(addr))
296 
297 #define MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(addr)			\
298 	MDIO_BUS_STATS_ADDR_ATTR(transfers, addr);			\
299 	MDIO_BUS_STATS_ADDR_ATTR(errors, addr);				\
300 	MDIO_BUS_STATS_ADDR_ATTR(writes, addr);				\
301 	MDIO_BUS_STATS_ADDR_ATTR(reads, addr)				\
302 
303 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(0);
304 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(1);
305 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(2);
306 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(3);
307 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(4);
308 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(5);
309 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(6);
310 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(7);
311 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(8);
312 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(9);
313 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(10);
314 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(11);
315 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(12);
316 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(13);
317 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(14);
318 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(15);
319 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(16);
320 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(17);
321 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(18);
322 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(19);
323 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(20);
324 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(21);
325 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(22);
326 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(23);
327 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(24);
328 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(25);
329 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(26);
330 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(27);
331 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(28);
332 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(29);
333 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(30);
334 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(31);
335 
336 #define MDIO_BUS_STATS_ADDR_ATTR_GROUP(addr)				\
337 	&dev_attr_mdio_bus_addr_transfers_##addr.attr.attr,		\
338 	&dev_attr_mdio_bus_addr_errors_##addr.attr.attr,		\
339 	&dev_attr_mdio_bus_addr_writes_##addr.attr.attr,		\
340 	&dev_attr_mdio_bus_addr_reads_##addr.attr.attr			\
341 
342 static struct attribute *mdio_bus_statistics_attrs[] = {
343 	&dev_attr_mdio_bus_transfers.attr.attr,
344 	&dev_attr_mdio_bus_errors.attr.attr,
345 	&dev_attr_mdio_bus_writes.attr.attr,
346 	&dev_attr_mdio_bus_reads.attr.attr,
347 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(0),
348 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(1),
349 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(2),
350 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(3),
351 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(4),
352 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(5),
353 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(6),
354 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(7),
355 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(8),
356 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(9),
357 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(10),
358 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(11),
359 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(12),
360 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(13),
361 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(14),
362 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(15),
363 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(16),
364 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(17),
365 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(18),
366 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(19),
367 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(20),
368 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(21),
369 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(22),
370 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(23),
371 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(24),
372 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(25),
373 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(26),
374 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(27),
375 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(28),
376 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(29),
377 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(30),
378 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(31),
379 	NULL,
380 };
381 
382 static const struct attribute_group mdio_bus_statistics_group = {
383 	.name	= "statistics",
384 	.attrs	= mdio_bus_statistics_attrs,
385 };
386 
387 static const struct attribute_group *mdio_bus_groups[] = {
388 	&mdio_bus_statistics_group,
389 	NULL,
390 };
391 
392 static struct class mdio_bus_class = {
393 	.name		= "mdio_bus",
394 	.dev_release	= mdiobus_release,
395 	.dev_groups	= mdio_bus_groups,
396 };
397 
398 /**
399  * mdio_find_bus - Given the name of a mdiobus, find the mii_bus.
400  * @mdio_name: The name of a mdiobus.
401  *
402  * Returns a reference to the mii_bus, or NULL if none found.  The
403  * embedded struct device will have its reference count incremented,
404  * and this must be put_deviced'ed once the bus is finished with.
405  */
mdio_find_bus(const char * mdio_name)406 struct mii_bus *mdio_find_bus(const char *mdio_name)
407 {
408 	struct device *d;
409 
410 	d = class_find_device_by_name(&mdio_bus_class, mdio_name);
411 	return d ? to_mii_bus(d) : NULL;
412 }
413 EXPORT_SYMBOL(mdio_find_bus);
414 
415 #if IS_ENABLED(CONFIG_OF_MDIO)
416 /**
417  * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
418  * @mdio_bus_np: Pointer to the mii_bus.
419  *
420  * Returns a reference to the mii_bus, or NULL if none found.  The
421  * embedded struct device will have its reference count incremented,
422  * and this must be put once the bus is finished with.
423  *
424  * Because the association of a device_node and mii_bus is made via
425  * of_mdiobus_register(), the mii_bus cannot be found before it is
426  * registered with of_mdiobus_register().
427  *
428  */
of_mdio_find_bus(struct device_node * mdio_bus_np)429 struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
430 {
431 	struct device *d;
432 
433 	if (!mdio_bus_np)
434 		return NULL;
435 
436 	d = class_find_device_by_of_node(&mdio_bus_class, mdio_bus_np);
437 	return d ? to_mii_bus(d) : NULL;
438 }
439 EXPORT_SYMBOL(of_mdio_find_bus);
440 
441 /* Walk the list of subnodes of a mdio bus and look for a node that
442  * matches the mdio device's address with its 'reg' property. If
443  * found, set the of_node pointer for the mdio device. This allows
444  * auto-probed phy devices to be supplied with information passed in
445  * via DT.
446  */
of_mdiobus_link_mdiodev(struct mii_bus * bus,struct mdio_device * mdiodev)447 static void of_mdiobus_link_mdiodev(struct mii_bus *bus,
448 				    struct mdio_device *mdiodev)
449 {
450 	struct device *dev = &mdiodev->dev;
451 	struct device_node *child;
452 
453 	if (dev->of_node || !bus->dev.of_node)
454 		return;
455 
456 	for_each_available_child_of_node(bus->dev.of_node, child) {
457 		int addr;
458 
459 		addr = of_mdio_parse_addr(dev, child);
460 		if (addr < 0)
461 			continue;
462 
463 		if (addr == mdiodev->addr) {
464 			device_set_node(dev, of_fwnode_handle(child));
465 			/* The refcount on "child" is passed to the mdio
466 			 * device. Do _not_ use of_node_put(child) here.
467 			 */
468 			return;
469 		}
470 	}
471 }
472 #else /* !IS_ENABLED(CONFIG_OF_MDIO) */
of_mdiobus_link_mdiodev(struct mii_bus * mdio,struct mdio_device * mdiodev)473 static inline void of_mdiobus_link_mdiodev(struct mii_bus *mdio,
474 					   struct mdio_device *mdiodev)
475 {
476 }
477 #endif
478 
479 /**
480  * mdiobus_create_device - create a full MDIO device given
481  * a mdio_board_info structure
482  * @bus: MDIO bus to create the devices on
483  * @bi: mdio_board_info structure describing the devices
484  *
485  * Returns 0 on success or < 0 on error.
486  */
mdiobus_create_device(struct mii_bus * bus,struct mdio_board_info * bi)487 static int mdiobus_create_device(struct mii_bus *bus,
488 				 struct mdio_board_info *bi)
489 {
490 	struct mdio_device *mdiodev;
491 	int ret = 0;
492 
493 	mdiodev = mdio_device_create(bus, bi->mdio_addr);
494 	if (IS_ERR(mdiodev))
495 		return -ENODEV;
496 
497 	strncpy(mdiodev->modalias, bi->modalias,
498 		sizeof(mdiodev->modalias));
499 	mdiodev->bus_match = mdio_device_bus_match;
500 	mdiodev->dev.platform_data = (void *)bi->platform_data;
501 
502 	ret = mdio_device_register(mdiodev);
503 	if (ret)
504 		mdio_device_free(mdiodev);
505 
506 	return ret;
507 }
508 
509 /**
510  * __mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
511  * @bus: target mii_bus
512  * @owner: module containing bus accessor functions
513  *
514  * Description: Called by a bus driver to bring up all the PHYs
515  *   on a given bus, and attach them to the bus. Drivers should use
516  *   mdiobus_register() rather than __mdiobus_register() unless they
517  *   need to pass a specific owner module. MDIO devices which are not
518  *   PHYs will not be brought up by this function. They are expected
519  *   to be explicitly listed in DT and instantiated by of_mdiobus_register().
520  *
521  * Returns 0 on success or < 0 on error.
522  */
__mdiobus_register(struct mii_bus * bus,struct module * owner)523 int __mdiobus_register(struct mii_bus *bus, struct module *owner)
524 {
525 	struct mdio_device *mdiodev;
526 	int i, err;
527 	struct gpio_desc *gpiod;
528 
529 	if (NULL == bus || NULL == bus->name ||
530 	    NULL == bus->read || NULL == bus->write)
531 		return -EINVAL;
532 
533 	if (bus->parent && bus->parent->of_node)
534 		bus->parent->of_node->fwnode.flags |=
535 					FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD;
536 
537 	WARN(bus->state != MDIOBUS_ALLOCATED &&
538 	     bus->state != MDIOBUS_UNREGISTERED,
539 	     "%s: not in ALLOCATED or UNREGISTERED state\n", bus->id);
540 
541 	bus->owner = owner;
542 	bus->dev.parent = bus->parent;
543 	bus->dev.class = &mdio_bus_class;
544 	bus->dev.groups = NULL;
545 	dev_set_name(&bus->dev, "%s", bus->id);
546 
547 	/* We need to set state to MDIOBUS_UNREGISTERED to correctly release
548 	 * the device in mdiobus_free()
549 	 *
550 	 * State will be updated later in this function in case of success
551 	 */
552 	bus->state = MDIOBUS_UNREGISTERED;
553 
554 	err = device_register(&bus->dev);
555 	if (err) {
556 		pr_err("mii_bus %s failed to register\n", bus->id);
557 		return -EINVAL;
558 	}
559 
560 	mutex_init(&bus->mdio_lock);
561 	mutex_init(&bus->shared_lock);
562 
563 	/* assert bus level PHY GPIO reset */
564 	gpiod = devm_gpiod_get_optional(&bus->dev, "reset", GPIOD_OUT_HIGH);
565 	if (IS_ERR(gpiod)) {
566 		err = dev_err_probe(&bus->dev, PTR_ERR(gpiod),
567 				    "mii_bus %s couldn't get reset GPIO\n",
568 				    bus->id);
569 		device_del(&bus->dev);
570 		return err;
571 	} else	if (gpiod) {
572 		bus->reset_gpiod = gpiod;
573 		fsleep(bus->reset_delay_us);
574 		gpiod_set_value_cansleep(gpiod, 0);
575 		if (bus->reset_post_delay_us > 0)
576 			fsleep(bus->reset_post_delay_us);
577 	}
578 
579 	if (bus->reset) {
580 		err = bus->reset(bus);
581 		if (err)
582 			goto error_reset_gpiod;
583 	}
584 
585 	for (i = 0; i < PHY_MAX_ADDR; i++) {
586 		if ((bus->phy_mask & (1 << i)) == 0) {
587 			struct phy_device *phydev;
588 
589 			phydev = mdiobus_scan(bus, i);
590 			if (IS_ERR(phydev) && (PTR_ERR(phydev) != -ENODEV)) {
591 				err = PTR_ERR(phydev);
592 				goto error;
593 			}
594 		}
595 	}
596 
597 	mdiobus_setup_mdiodev_from_board_info(bus, mdiobus_create_device);
598 
599 	bus->state = MDIOBUS_REGISTERED;
600 	dev_dbg(&bus->dev, "probed\n");
601 	return 0;
602 
603 error:
604 	while (--i >= 0) {
605 		mdiodev = bus->mdio_map[i];
606 		if (!mdiodev)
607 			continue;
608 
609 		mdiodev->device_remove(mdiodev);
610 		mdiodev->device_free(mdiodev);
611 	}
612 error_reset_gpiod:
613 	/* Put PHYs in RESET to save power */
614 	if (bus->reset_gpiod)
615 		gpiod_set_value_cansleep(bus->reset_gpiod, 1);
616 
617 	device_del(&bus->dev);
618 	return err;
619 }
620 EXPORT_SYMBOL(__mdiobus_register);
621 
mdiobus_unregister(struct mii_bus * bus)622 void mdiobus_unregister(struct mii_bus *bus)
623 {
624 	struct mdio_device *mdiodev;
625 	int i;
626 
627 	if (WARN_ON_ONCE(bus->state != MDIOBUS_REGISTERED))
628 		return;
629 	bus->state = MDIOBUS_UNREGISTERED;
630 
631 	for (i = 0; i < PHY_MAX_ADDR; i++) {
632 		mdiodev = bus->mdio_map[i];
633 		if (!mdiodev)
634 			continue;
635 
636 		if (mdiodev->reset_gpio)
637 			gpiod_put(mdiodev->reset_gpio);
638 
639 		mdiodev->device_remove(mdiodev);
640 		mdiodev->device_free(mdiodev);
641 	}
642 
643 	/* Put PHYs in RESET to save power */
644 	if (bus->reset_gpiod)
645 		gpiod_set_value_cansleep(bus->reset_gpiod, 1);
646 
647 	device_del(&bus->dev);
648 }
649 EXPORT_SYMBOL(mdiobus_unregister);
650 
651 /**
652  * mdiobus_free - free a struct mii_bus
653  * @bus: mii_bus to free
654  *
655  * This function releases the reference to the underlying device
656  * object in the mii_bus.  If this is the last reference, the mii_bus
657  * will be freed.
658  */
mdiobus_free(struct mii_bus * bus)659 void mdiobus_free(struct mii_bus *bus)
660 {
661 	/* For compatibility with error handling in drivers. */
662 	if (bus->state == MDIOBUS_ALLOCATED) {
663 		kfree(bus);
664 		return;
665 	}
666 
667 	WARN(bus->state != MDIOBUS_UNREGISTERED,
668 	     "%s: not in UNREGISTERED state\n", bus->id);
669 	bus->state = MDIOBUS_RELEASED;
670 
671 	put_device(&bus->dev);
672 }
673 EXPORT_SYMBOL(mdiobus_free);
674 
675 /**
676  * mdiobus_scan - scan a bus for MDIO devices.
677  * @bus: mii_bus to scan
678  * @addr: address on bus to scan
679  *
680  * This function scans the MDIO bus, looking for devices which can be
681  * identified using a vendor/product ID in registers 2 and 3. Not all
682  * MDIO devices have such registers, but PHY devices typically
683  * do. Hence this function assumes anything found is a PHY, or can be
684  * treated as a PHY. Other MDIO devices, such as switches, will
685  * probably not be found during the scan.
686  */
mdiobus_scan(struct mii_bus * bus,int addr)687 struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
688 {
689 	struct phy_device *phydev = ERR_PTR(-ENODEV);
690 	int err;
691 
692 	switch (bus->probe_capabilities) {
693 	case MDIOBUS_NO_CAP:
694 	case MDIOBUS_C22:
695 		phydev = get_phy_device(bus, addr, false);
696 		break;
697 	case MDIOBUS_C45:
698 		phydev = get_phy_device(bus, addr, true);
699 		break;
700 	case MDIOBUS_C22_C45:
701 		phydev = get_phy_device(bus, addr, false);
702 		if (IS_ERR(phydev))
703 			phydev = get_phy_device(bus, addr, true);
704 		break;
705 	}
706 
707 	if (IS_ERR(phydev))
708 		return phydev;
709 
710 	/*
711 	 * For DT, see if the auto-probed phy has a correspoding child
712 	 * in the bus node, and set the of_node pointer in this case.
713 	 */
714 	of_mdiobus_link_mdiodev(bus, &phydev->mdio);
715 
716 	err = phy_device_register(phydev);
717 	if (err) {
718 		phy_device_free(phydev);
719 		return ERR_PTR(-ENODEV);
720 	}
721 
722 	return phydev;
723 }
724 EXPORT_SYMBOL(mdiobus_scan);
725 
mdiobus_stats_acct(struct mdio_bus_stats * stats,bool op,int ret)726 static void mdiobus_stats_acct(struct mdio_bus_stats *stats, bool op, int ret)
727 {
728 	preempt_disable();
729 	u64_stats_update_begin(&stats->syncp);
730 
731 	u64_stats_inc(&stats->transfers);
732 	if (ret < 0) {
733 		u64_stats_inc(&stats->errors);
734 		goto out;
735 	}
736 
737 	if (op)
738 		u64_stats_inc(&stats->reads);
739 	else
740 		u64_stats_inc(&stats->writes);
741 out:
742 	u64_stats_update_end(&stats->syncp);
743 	preempt_enable();
744 }
745 
746 /**
747  * __mdiobus_read - Unlocked version of the mdiobus_read function
748  * @bus: the mii_bus struct
749  * @addr: the phy address
750  * @regnum: register number to read
751  *
752  * Read a MDIO bus register. Caller must hold the mdio bus lock.
753  *
754  * NOTE: MUST NOT be called from interrupt context.
755  */
__mdiobus_read(struct mii_bus * bus,int addr,u32 regnum)756 int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
757 {
758 	int retval;
759 
760 	lockdep_assert_held_once(&bus->mdio_lock);
761 
762 	retval = bus->read(bus, addr, regnum);
763 
764 	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
765 	mdiobus_stats_acct(&bus->stats[addr], true, retval);
766 
767 	return retval;
768 }
769 EXPORT_SYMBOL(__mdiobus_read);
770 
771 /**
772  * __mdiobus_write - Unlocked version of the mdiobus_write function
773  * @bus: the mii_bus struct
774  * @addr: the phy address
775  * @regnum: register number to write
776  * @val: value to write to @regnum
777  *
778  * Write a MDIO bus register. Caller must hold the mdio bus lock.
779  *
780  * NOTE: MUST NOT be called from interrupt context.
781  */
__mdiobus_write(struct mii_bus * bus,int addr,u32 regnum,u16 val)782 int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
783 {
784 	int err;
785 
786 	lockdep_assert_held_once(&bus->mdio_lock);
787 
788 	err = bus->write(bus, addr, regnum, val);
789 
790 	trace_mdio_access(bus, 0, addr, regnum, val, err);
791 	mdiobus_stats_acct(&bus->stats[addr], false, err);
792 
793 	return err;
794 }
795 EXPORT_SYMBOL(__mdiobus_write);
796 
797 /**
798  * __mdiobus_modify_changed - Unlocked version of the mdiobus_modify function
799  * @bus: the mii_bus struct
800  * @addr: the phy address
801  * @regnum: register number to modify
802  * @mask: bit mask of bits to clear
803  * @set: bit mask of bits to set
804  *
805  * Read, modify, and if any change, write the register value back to the
806  * device. Any error returns a negative number.
807  *
808  * NOTE: MUST NOT be called from interrupt context.
809  */
__mdiobus_modify_changed(struct mii_bus * bus,int addr,u32 regnum,u16 mask,u16 set)810 int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
811 			     u16 mask, u16 set)
812 {
813 	int new, ret;
814 
815 	ret = __mdiobus_read(bus, addr, regnum);
816 	if (ret < 0)
817 		return ret;
818 
819 	new = (ret & ~mask) | set;
820 	if (new == ret)
821 		return 0;
822 
823 	ret = __mdiobus_write(bus, addr, regnum, new);
824 
825 	return ret < 0 ? ret : 1;
826 }
827 EXPORT_SYMBOL_GPL(__mdiobus_modify_changed);
828 
829 /**
830  * mdiobus_read_nested - Nested version of the mdiobus_read function
831  * @bus: the mii_bus struct
832  * @addr: the phy address
833  * @regnum: register number to read
834  *
835  * In case of nested MDIO bus access avoid lockdep false positives by
836  * using mutex_lock_nested().
837  *
838  * NOTE: MUST NOT be called from interrupt context,
839  * because the bus read/write functions may wait for an interrupt
840  * to conclude the operation.
841  */
mdiobus_read_nested(struct mii_bus * bus,int addr,u32 regnum)842 int mdiobus_read_nested(struct mii_bus *bus, int addr, u32 regnum)
843 {
844 	int retval;
845 
846 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
847 	retval = __mdiobus_read(bus, addr, regnum);
848 	mutex_unlock(&bus->mdio_lock);
849 
850 	return retval;
851 }
852 EXPORT_SYMBOL(mdiobus_read_nested);
853 
854 /**
855  * mdiobus_read - Convenience function for reading a given MII mgmt register
856  * @bus: the mii_bus struct
857  * @addr: the phy address
858  * @regnum: register number to read
859  *
860  * NOTE: MUST NOT be called from interrupt context,
861  * because the bus read/write functions may wait for an interrupt
862  * to conclude the operation.
863  */
mdiobus_read(struct mii_bus * bus,int addr,u32 regnum)864 int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
865 {
866 	int retval;
867 
868 	mutex_lock(&bus->mdio_lock);
869 	retval = __mdiobus_read(bus, addr, regnum);
870 	mutex_unlock(&bus->mdio_lock);
871 
872 	return retval;
873 }
874 EXPORT_SYMBOL(mdiobus_read);
875 
876 /**
877  * mdiobus_write_nested - Nested version of the mdiobus_write function
878  * @bus: the mii_bus struct
879  * @addr: the phy address
880  * @regnum: register number to write
881  * @val: value to write to @regnum
882  *
883  * In case of nested MDIO bus access avoid lockdep false positives by
884  * using mutex_lock_nested().
885  *
886  * NOTE: MUST NOT be called from interrupt context,
887  * because the bus read/write functions may wait for an interrupt
888  * to conclude the operation.
889  */
mdiobus_write_nested(struct mii_bus * bus,int addr,u32 regnum,u16 val)890 int mdiobus_write_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val)
891 {
892 	int err;
893 
894 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
895 	err = __mdiobus_write(bus, addr, regnum, val);
896 	mutex_unlock(&bus->mdio_lock);
897 
898 	return err;
899 }
900 EXPORT_SYMBOL(mdiobus_write_nested);
901 
902 /**
903  * mdiobus_write - Convenience function for writing a given MII mgmt register
904  * @bus: the mii_bus struct
905  * @addr: the phy address
906  * @regnum: register number to write
907  * @val: value to write to @regnum
908  *
909  * NOTE: MUST NOT be called from interrupt context,
910  * because the bus read/write functions may wait for an interrupt
911  * to conclude the operation.
912  */
mdiobus_write(struct mii_bus * bus,int addr,u32 regnum,u16 val)913 int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
914 {
915 	int err;
916 
917 	mutex_lock(&bus->mdio_lock);
918 	err = __mdiobus_write(bus, addr, regnum, val);
919 	mutex_unlock(&bus->mdio_lock);
920 
921 	return err;
922 }
923 EXPORT_SYMBOL(mdiobus_write);
924 
925 /**
926  * mdiobus_modify - Convenience function for modifying a given mdio device
927  *	register
928  * @bus: the mii_bus struct
929  * @addr: the phy address
930  * @regnum: register number to write
931  * @mask: bit mask of bits to clear
932  * @set: bit mask of bits to set
933  */
mdiobus_modify(struct mii_bus * bus,int addr,u32 regnum,u16 mask,u16 set)934 int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask, u16 set)
935 {
936 	int err;
937 
938 	mutex_lock(&bus->mdio_lock);
939 	err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
940 	mutex_unlock(&bus->mdio_lock);
941 
942 	return err < 0 ? err : 0;
943 }
944 EXPORT_SYMBOL_GPL(mdiobus_modify);
945 
946 /**
947  * mdiobus_modify_changed - Convenience function for modifying a given mdio
948  *	device register and returning if it changed
949  * @bus: the mii_bus struct
950  * @addr: the phy address
951  * @regnum: register number to write
952  * @mask: bit mask of bits to clear
953  * @set: bit mask of bits to set
954  */
mdiobus_modify_changed(struct mii_bus * bus,int addr,u32 regnum,u16 mask,u16 set)955 int mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
956 			   u16 mask, u16 set)
957 {
958 	int err;
959 
960 	mutex_lock(&bus->mdio_lock);
961 	err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
962 	mutex_unlock(&bus->mdio_lock);
963 
964 	return err;
965 }
966 EXPORT_SYMBOL_GPL(mdiobus_modify_changed);
967 
968 /**
969  * mdio_bus_match - determine if given MDIO driver supports the given
970  *		    MDIO device
971  * @dev: target MDIO device
972  * @drv: given MDIO driver
973  *
974  * Description: Given a MDIO device, and a MDIO driver, return 1 if
975  *   the driver supports the device.  Otherwise, return 0. This may
976  *   require calling the devices own match function, since different classes
977  *   of MDIO devices have different match criteria.
978  */
mdio_bus_match(struct device * dev,struct device_driver * drv)979 static int mdio_bus_match(struct device *dev, struct device_driver *drv)
980 {
981 	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
982 	struct mdio_device *mdio = to_mdio_device(dev);
983 
984 	/* Both the driver and device must type-match */
985 	if (!(mdiodrv->mdiodrv.flags & MDIO_DEVICE_IS_PHY) !=
986 	    !(mdio->flags & MDIO_DEVICE_FLAG_PHY))
987 		return 0;
988 
989 	if (of_driver_match_device(dev, drv))
990 		return 1;
991 
992 	if (mdio->bus_match)
993 		return mdio->bus_match(dev, drv);
994 
995 	return 0;
996 }
997 
mdio_uevent(struct device * dev,struct kobj_uevent_env * env)998 static int mdio_uevent(struct device *dev, struct kobj_uevent_env *env)
999 {
1000 	int rc;
1001 
1002 	/* Some devices have extra OF data and an OF-style MODALIAS */
1003 	rc = of_device_uevent_modalias(dev, env);
1004 	if (rc != -ENODEV)
1005 		return rc;
1006 
1007 	return 0;
1008 }
1009 
1010 static struct attribute *mdio_bus_device_statistics_attrs[] = {
1011 	&dev_attr_mdio_bus_device_transfers.attr.attr,
1012 	&dev_attr_mdio_bus_device_errors.attr.attr,
1013 	&dev_attr_mdio_bus_device_writes.attr.attr,
1014 	&dev_attr_mdio_bus_device_reads.attr.attr,
1015 	NULL,
1016 };
1017 
1018 static const struct attribute_group mdio_bus_device_statistics_group = {
1019 	.name	= "statistics",
1020 	.attrs	= mdio_bus_device_statistics_attrs,
1021 };
1022 
1023 static const struct attribute_group *mdio_bus_dev_groups[] = {
1024 	&mdio_bus_device_statistics_group,
1025 	NULL,
1026 };
1027 
1028 struct bus_type mdio_bus_type = {
1029 	.name		= "mdio_bus",
1030 	.dev_groups	= mdio_bus_dev_groups,
1031 	.match		= mdio_bus_match,
1032 	.uevent		= mdio_uevent,
1033 };
1034 EXPORT_SYMBOL(mdio_bus_type);
1035 
mdio_bus_init(void)1036 int __init mdio_bus_init(void)
1037 {
1038 	int ret;
1039 
1040 	ret = class_register(&mdio_bus_class);
1041 	if (!ret) {
1042 		ret = bus_register(&mdio_bus_type);
1043 		if (ret)
1044 			class_unregister(&mdio_bus_class);
1045 	}
1046 
1047 	return ret;
1048 }
1049 
1050 #if IS_ENABLED(CONFIG_PHYLIB)
mdio_bus_exit(void)1051 void mdio_bus_exit(void)
1052 {
1053 	class_unregister(&mdio_bus_class);
1054 	bus_unregister(&mdio_bus_type);
1055 }
1056 EXPORT_SYMBOL_GPL(mdio_bus_exit);
1057 #else
1058 module_init(mdio_bus_init);
1059 /* no module_exit, intentional */
1060 MODULE_LICENSE("GPL");
1061 MODULE_DESCRIPTION("MDIO bus/device layer");
1062 #endif
1063