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;
112 
113 	if (addr < 0 || addr >= ARRAY_SIZE(bus->mdio_map))
114 		return NULL;
115 
116 	mdiodev = bus->mdio_map[addr];
117 
118 	if (!mdiodev)
119 		return NULL;
120 
121 	if (!(mdiodev->flags & MDIO_DEVICE_FLAG_PHY))
122 		return NULL;
123 
124 	return container_of(mdiodev, struct phy_device, mdio);
125 }
126 EXPORT_SYMBOL(mdiobus_get_phy);
127 
mdiobus_is_registered_device(struct mii_bus * bus,int addr)128 bool mdiobus_is_registered_device(struct mii_bus *bus, int addr)
129 {
130 	return bus->mdio_map[addr];
131 }
132 EXPORT_SYMBOL(mdiobus_is_registered_device);
133 
134 /**
135  * mdiobus_alloc_size - allocate a mii_bus structure
136  * @size: extra amount of memory to allocate for private storage.
137  * If non-zero, then bus->priv is points to that memory.
138  *
139  * Description: called by a bus driver to allocate an mii_bus
140  * structure to fill in.
141  */
mdiobus_alloc_size(size_t size)142 struct mii_bus *mdiobus_alloc_size(size_t size)
143 {
144 	struct mii_bus *bus;
145 	size_t aligned_size = ALIGN(sizeof(*bus), NETDEV_ALIGN);
146 	size_t alloc_size;
147 	int i;
148 
149 	/* If we alloc extra space, it should be aligned */
150 	if (size)
151 		alloc_size = aligned_size + size;
152 	else
153 		alloc_size = sizeof(*bus);
154 
155 	bus = kzalloc(alloc_size, GFP_KERNEL);
156 	if (!bus)
157 		return NULL;
158 
159 	bus->state = MDIOBUS_ALLOCATED;
160 	if (size)
161 		bus->priv = (void *)bus + aligned_size;
162 
163 	/* Initialise the interrupts to polling and 64-bit seqcounts */
164 	for (i = 0; i < PHY_MAX_ADDR; i++) {
165 		bus->irq[i] = PHY_POLL;
166 		u64_stats_init(&bus->stats[i].syncp);
167 	}
168 
169 	return bus;
170 }
171 EXPORT_SYMBOL(mdiobus_alloc_size);
172 
173 /**
174  * mdiobus_release - mii_bus device release callback
175  * @d: the target struct device that contains the mii_bus
176  *
177  * Description: called when the last reference to an mii_bus is
178  * dropped, to free the underlying memory.
179  */
mdiobus_release(struct device * d)180 static void mdiobus_release(struct device *d)
181 {
182 	struct mii_bus *bus = to_mii_bus(d);
183 
184 	WARN(bus->state != MDIOBUS_RELEASED &&
185 	     /* for compatibility with error handling in drivers */
186 	     bus->state != MDIOBUS_ALLOCATED,
187 	     "%s: not in RELEASED or ALLOCATED state\n",
188 	     bus->id);
189 	kfree(bus);
190 }
191 
192 struct mdio_bus_stat_attr {
193 	int addr;
194 	unsigned int field_offset;
195 };
196 
mdio_bus_get_stat(struct mdio_bus_stats * s,unsigned int offset)197 static u64 mdio_bus_get_stat(struct mdio_bus_stats *s, unsigned int offset)
198 {
199 	const char *p = (const char *)s + offset;
200 	unsigned int start;
201 	u64 val = 0;
202 
203 	do {
204 		start = u64_stats_fetch_begin(&s->syncp);
205 		val = u64_stats_read((const u64_stats_t *)p);
206 	} while (u64_stats_fetch_retry(&s->syncp, start));
207 
208 	return val;
209 }
210 
mdio_bus_get_global_stat(struct mii_bus * bus,unsigned int offset)211 static u64 mdio_bus_get_global_stat(struct mii_bus *bus, unsigned int offset)
212 {
213 	unsigned int i;
214 	u64 val = 0;
215 
216 	for (i = 0; i < PHY_MAX_ADDR; i++)
217 		val += mdio_bus_get_stat(&bus->stats[i], offset);
218 
219 	return val;
220 }
221 
mdio_bus_stat_field_show(struct device * dev,struct device_attribute * attr,char * buf)222 static ssize_t mdio_bus_stat_field_show(struct device *dev,
223 					struct device_attribute *attr,
224 					char *buf)
225 {
226 	struct mii_bus *bus = to_mii_bus(dev);
227 	struct mdio_bus_stat_attr *sattr;
228 	struct dev_ext_attribute *eattr;
229 	u64 val;
230 
231 	eattr = container_of(attr, struct dev_ext_attribute, attr);
232 	sattr = eattr->var;
233 
234 	if (sattr->addr < 0)
235 		val = mdio_bus_get_global_stat(bus, sattr->field_offset);
236 	else
237 		val = mdio_bus_get_stat(&bus->stats[sattr->addr],
238 					sattr->field_offset);
239 
240 	return sysfs_emit(buf, "%llu\n", val);
241 }
242 
mdio_bus_device_stat_field_show(struct device * dev,struct device_attribute * attr,char * buf)243 static ssize_t mdio_bus_device_stat_field_show(struct device *dev,
244 					       struct device_attribute *attr,
245 					       char *buf)
246 {
247 	struct mdio_device *mdiodev = to_mdio_device(dev);
248 	struct mii_bus *bus = mdiodev->bus;
249 	struct mdio_bus_stat_attr *sattr;
250 	struct dev_ext_attribute *eattr;
251 	int addr = mdiodev->addr;
252 	u64 val;
253 
254 	eattr = container_of(attr, struct dev_ext_attribute, attr);
255 	sattr = eattr->var;
256 
257 	val = mdio_bus_get_stat(&bus->stats[addr], sattr->field_offset);
258 
259 	return sysfs_emit(buf, "%llu\n", val);
260 }
261 
262 #define MDIO_BUS_STATS_ATTR_DECL(field, file)				\
263 static struct dev_ext_attribute dev_attr_mdio_bus_##field = {		\
264 	.attr = { .attr = { .name = file, .mode = 0444 },		\
265 		     .show = mdio_bus_stat_field_show,			\
266 	},								\
267 	.var = &((struct mdio_bus_stat_attr) {				\
268 		-1, offsetof(struct mdio_bus_stats, field)		\
269 	}),								\
270 };									\
271 static struct dev_ext_attribute dev_attr_mdio_bus_device_##field = {	\
272 	.attr = { .attr = { .name = file, .mode = 0444 },		\
273 		     .show = mdio_bus_device_stat_field_show,		\
274 	},								\
275 	.var = &((struct mdio_bus_stat_attr) {				\
276 		-1, offsetof(struct mdio_bus_stats, field)		\
277 	}),								\
278 };
279 
280 #define MDIO_BUS_STATS_ATTR(field)					\
281 	MDIO_BUS_STATS_ATTR_DECL(field, __stringify(field))
282 
283 MDIO_BUS_STATS_ATTR(transfers);
284 MDIO_BUS_STATS_ATTR(errors);
285 MDIO_BUS_STATS_ATTR(writes);
286 MDIO_BUS_STATS_ATTR(reads);
287 
288 #define MDIO_BUS_STATS_ADDR_ATTR_DECL(field, addr, file)		\
289 static struct dev_ext_attribute dev_attr_mdio_bus_addr_##field##_##addr = { \
290 	.attr = { .attr = { .name = file, .mode = 0444 },		\
291 		     .show = mdio_bus_stat_field_show,			\
292 	},								\
293 	.var = &((struct mdio_bus_stat_attr) {				\
294 		addr, offsetof(struct mdio_bus_stats, field)		\
295 	}),								\
296 }
297 
298 #define MDIO_BUS_STATS_ADDR_ATTR(field, addr)				\
299 	MDIO_BUS_STATS_ADDR_ATTR_DECL(field, addr,			\
300 				 __stringify(field) "_" __stringify(addr))
301 
302 #define MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(addr)			\
303 	MDIO_BUS_STATS_ADDR_ATTR(transfers, addr);			\
304 	MDIO_BUS_STATS_ADDR_ATTR(errors, addr);				\
305 	MDIO_BUS_STATS_ADDR_ATTR(writes, addr);				\
306 	MDIO_BUS_STATS_ADDR_ATTR(reads, addr)				\
307 
308 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(0);
309 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(1);
310 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(2);
311 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(3);
312 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(4);
313 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(5);
314 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(6);
315 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(7);
316 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(8);
317 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(9);
318 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(10);
319 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(11);
320 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(12);
321 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(13);
322 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(14);
323 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(15);
324 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(16);
325 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(17);
326 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(18);
327 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(19);
328 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(20);
329 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(21);
330 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(22);
331 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(23);
332 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(24);
333 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(25);
334 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(26);
335 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(27);
336 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(28);
337 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(29);
338 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(30);
339 MDIO_BUS_STATS_ADDR_ATTR_GROUP_DECL(31);
340 
341 #define MDIO_BUS_STATS_ADDR_ATTR_GROUP(addr)				\
342 	&dev_attr_mdio_bus_addr_transfers_##addr.attr.attr,		\
343 	&dev_attr_mdio_bus_addr_errors_##addr.attr.attr,		\
344 	&dev_attr_mdio_bus_addr_writes_##addr.attr.attr,		\
345 	&dev_attr_mdio_bus_addr_reads_##addr.attr.attr			\
346 
347 static struct attribute *mdio_bus_statistics_attrs[] = {
348 	&dev_attr_mdio_bus_transfers.attr.attr,
349 	&dev_attr_mdio_bus_errors.attr.attr,
350 	&dev_attr_mdio_bus_writes.attr.attr,
351 	&dev_attr_mdio_bus_reads.attr.attr,
352 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(0),
353 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(1),
354 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(2),
355 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(3),
356 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(4),
357 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(5),
358 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(6),
359 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(7),
360 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(8),
361 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(9),
362 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(10),
363 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(11),
364 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(12),
365 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(13),
366 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(14),
367 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(15),
368 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(16),
369 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(17),
370 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(18),
371 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(19),
372 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(20),
373 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(21),
374 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(22),
375 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(23),
376 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(24),
377 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(25),
378 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(26),
379 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(27),
380 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(28),
381 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(29),
382 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(30),
383 	MDIO_BUS_STATS_ADDR_ATTR_GROUP(31),
384 	NULL,
385 };
386 
387 static const struct attribute_group mdio_bus_statistics_group = {
388 	.name	= "statistics",
389 	.attrs	= mdio_bus_statistics_attrs,
390 };
391 
392 static const struct attribute_group *mdio_bus_groups[] = {
393 	&mdio_bus_statistics_group,
394 	NULL,
395 };
396 
397 static struct class mdio_bus_class = {
398 	.name		= "mdio_bus",
399 	.dev_release	= mdiobus_release,
400 	.dev_groups	= mdio_bus_groups,
401 };
402 
403 /**
404  * mdio_find_bus - Given the name of a mdiobus, find the mii_bus.
405  * @mdio_name: The name of a mdiobus.
406  *
407  * Returns a reference to the mii_bus, or NULL if none found.  The
408  * embedded struct device will have its reference count incremented,
409  * and this must be put_deviced'ed once the bus is finished with.
410  */
mdio_find_bus(const char * mdio_name)411 struct mii_bus *mdio_find_bus(const char *mdio_name)
412 {
413 	struct device *d;
414 
415 	d = class_find_device_by_name(&mdio_bus_class, mdio_name);
416 	return d ? to_mii_bus(d) : NULL;
417 }
418 EXPORT_SYMBOL(mdio_find_bus);
419 
420 #if IS_ENABLED(CONFIG_OF_MDIO)
421 /**
422  * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.
423  * @mdio_bus_np: Pointer to the mii_bus.
424  *
425  * Returns a reference to the mii_bus, or NULL if none found.  The
426  * embedded struct device will have its reference count incremented,
427  * and this must be put once the bus is finished with.
428  *
429  * Because the association of a device_node and mii_bus is made via
430  * of_mdiobus_register(), the mii_bus cannot be found before it is
431  * registered with of_mdiobus_register().
432  *
433  */
of_mdio_find_bus(struct device_node * mdio_bus_np)434 struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
435 {
436 	struct device *d;
437 
438 	if (!mdio_bus_np)
439 		return NULL;
440 
441 	d = class_find_device_by_of_node(&mdio_bus_class, mdio_bus_np);
442 	return d ? to_mii_bus(d) : NULL;
443 }
444 EXPORT_SYMBOL(of_mdio_find_bus);
445 
446 /* Walk the list of subnodes of a mdio bus and look for a node that
447  * matches the mdio device's address with its 'reg' property. If
448  * found, set the of_node pointer for the mdio device. This allows
449  * auto-probed phy devices to be supplied with information passed in
450  * via DT.
451  */
of_mdiobus_link_mdiodev(struct mii_bus * bus,struct mdio_device * mdiodev)452 static void of_mdiobus_link_mdiodev(struct mii_bus *bus,
453 				    struct mdio_device *mdiodev)
454 {
455 	struct device *dev = &mdiodev->dev;
456 	struct device_node *child;
457 
458 	if (dev->of_node || !bus->dev.of_node)
459 		return;
460 
461 	for_each_available_child_of_node(bus->dev.of_node, child) {
462 		int addr;
463 
464 		addr = of_mdio_parse_addr(dev, child);
465 		if (addr < 0)
466 			continue;
467 
468 		if (addr == mdiodev->addr) {
469 			device_set_node(dev, of_fwnode_handle(child));
470 			/* The refcount on "child" is passed to the mdio
471 			 * device. Do _not_ use of_node_put(child) here.
472 			 */
473 			return;
474 		}
475 	}
476 }
477 #else /* !IS_ENABLED(CONFIG_OF_MDIO) */
of_mdiobus_link_mdiodev(struct mii_bus * mdio,struct mdio_device * mdiodev)478 static inline void of_mdiobus_link_mdiodev(struct mii_bus *mdio,
479 					   struct mdio_device *mdiodev)
480 {
481 }
482 #endif
483 
484 /**
485  * mdiobus_create_device - create a full MDIO device given
486  * a mdio_board_info structure
487  * @bus: MDIO bus to create the devices on
488  * @bi: mdio_board_info structure describing the devices
489  *
490  * Returns 0 on success or < 0 on error.
491  */
mdiobus_create_device(struct mii_bus * bus,struct mdio_board_info * bi)492 static int mdiobus_create_device(struct mii_bus *bus,
493 				 struct mdio_board_info *bi)
494 {
495 	struct mdio_device *mdiodev;
496 	int ret = 0;
497 
498 	mdiodev = mdio_device_create(bus, bi->mdio_addr);
499 	if (IS_ERR(mdiodev))
500 		return -ENODEV;
501 
502 	strncpy(mdiodev->modalias, bi->modalias,
503 		sizeof(mdiodev->modalias));
504 	mdiodev->bus_match = mdio_device_bus_match;
505 	mdiodev->dev.platform_data = (void *)bi->platform_data;
506 
507 	ret = mdio_device_register(mdiodev);
508 	if (ret)
509 		mdio_device_free(mdiodev);
510 
511 	return ret;
512 }
513 
514 /**
515  * __mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
516  * @bus: target mii_bus
517  * @owner: module containing bus accessor functions
518  *
519  * Description: Called by a bus driver to bring up all the PHYs
520  *   on a given bus, and attach them to the bus. Drivers should use
521  *   mdiobus_register() rather than __mdiobus_register() unless they
522  *   need to pass a specific owner module. MDIO devices which are not
523  *   PHYs will not be brought up by this function. They are expected
524  *   to be explicitly listed in DT and instantiated by of_mdiobus_register().
525  *
526  * Returns 0 on success or < 0 on error.
527  */
__mdiobus_register(struct mii_bus * bus,struct module * owner)528 int __mdiobus_register(struct mii_bus *bus, struct module *owner)
529 {
530 	struct mdio_device *mdiodev;
531 	int i, err;
532 	struct gpio_desc *gpiod;
533 
534 	if (NULL == bus || NULL == bus->name ||
535 	    NULL == bus->read || NULL == bus->write)
536 		return -EINVAL;
537 
538 	if (bus->parent && bus->parent->of_node)
539 		bus->parent->of_node->fwnode.flags |=
540 					FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD;
541 
542 	WARN(bus->state != MDIOBUS_ALLOCATED &&
543 	     bus->state != MDIOBUS_UNREGISTERED,
544 	     "%s: not in ALLOCATED or UNREGISTERED state\n", bus->id);
545 
546 	bus->owner = owner;
547 	bus->dev.parent = bus->parent;
548 	bus->dev.class = &mdio_bus_class;
549 	bus->dev.groups = NULL;
550 	dev_set_name(&bus->dev, "%s", bus->id);
551 
552 	/* We need to set state to MDIOBUS_UNREGISTERED to correctly release
553 	 * the device in mdiobus_free()
554 	 *
555 	 * State will be updated later in this function in case of success
556 	 */
557 	bus->state = MDIOBUS_UNREGISTERED;
558 
559 	err = device_register(&bus->dev);
560 	if (err) {
561 		pr_err("mii_bus %s failed to register\n", bus->id);
562 		return -EINVAL;
563 	}
564 
565 	mutex_init(&bus->mdio_lock);
566 	mutex_init(&bus->shared_lock);
567 
568 	/* assert bus level PHY GPIO reset */
569 	gpiod = devm_gpiod_get_optional(&bus->dev, "reset", GPIOD_OUT_HIGH);
570 	if (IS_ERR(gpiod)) {
571 		err = dev_err_probe(&bus->dev, PTR_ERR(gpiod),
572 				    "mii_bus %s couldn't get reset GPIO\n",
573 				    bus->id);
574 		device_del(&bus->dev);
575 		return err;
576 	} else	if (gpiod) {
577 		bus->reset_gpiod = gpiod;
578 		fsleep(bus->reset_delay_us);
579 		gpiod_set_value_cansleep(gpiod, 0);
580 		if (bus->reset_post_delay_us > 0)
581 			fsleep(bus->reset_post_delay_us);
582 	}
583 
584 	if (bus->reset) {
585 		err = bus->reset(bus);
586 		if (err)
587 			goto error_reset_gpiod;
588 	}
589 
590 	for (i = 0; i < PHY_MAX_ADDR; i++) {
591 		if ((bus->phy_mask & BIT(i)) == 0) {
592 			struct phy_device *phydev;
593 
594 			phydev = mdiobus_scan(bus, i);
595 			if (IS_ERR(phydev) && (PTR_ERR(phydev) != -ENODEV)) {
596 				err = PTR_ERR(phydev);
597 				goto error;
598 			}
599 		}
600 	}
601 
602 	mdiobus_setup_mdiodev_from_board_info(bus, mdiobus_create_device);
603 
604 	bus->state = MDIOBUS_REGISTERED;
605 	dev_dbg(&bus->dev, "probed\n");
606 	return 0;
607 
608 error:
609 	while (--i >= 0) {
610 		mdiodev = bus->mdio_map[i];
611 		if (!mdiodev)
612 			continue;
613 
614 		mdiodev->device_remove(mdiodev);
615 		mdiodev->device_free(mdiodev);
616 	}
617 error_reset_gpiod:
618 	/* Put PHYs in RESET to save power */
619 	if (bus->reset_gpiod)
620 		gpiod_set_value_cansleep(bus->reset_gpiod, 1);
621 
622 	device_del(&bus->dev);
623 	return err;
624 }
625 EXPORT_SYMBOL(__mdiobus_register);
626 
mdiobus_unregister(struct mii_bus * bus)627 void mdiobus_unregister(struct mii_bus *bus)
628 {
629 	struct mdio_device *mdiodev;
630 	int i;
631 
632 	if (WARN_ON_ONCE(bus->state != MDIOBUS_REGISTERED))
633 		return;
634 	bus->state = MDIOBUS_UNREGISTERED;
635 
636 	for (i = 0; i < PHY_MAX_ADDR; i++) {
637 		mdiodev = bus->mdio_map[i];
638 		if (!mdiodev)
639 			continue;
640 
641 		if (mdiodev->reset_gpio)
642 			gpiod_put(mdiodev->reset_gpio);
643 
644 		mdiodev->device_remove(mdiodev);
645 		mdiodev->device_free(mdiodev);
646 	}
647 
648 	/* Put PHYs in RESET to save power */
649 	if (bus->reset_gpiod)
650 		gpiod_set_value_cansleep(bus->reset_gpiod, 1);
651 
652 	device_del(&bus->dev);
653 }
654 EXPORT_SYMBOL(mdiobus_unregister);
655 
656 /**
657  * mdiobus_free - free a struct mii_bus
658  * @bus: mii_bus to free
659  *
660  * This function releases the reference to the underlying device
661  * object in the mii_bus.  If this is the last reference, the mii_bus
662  * will be freed.
663  */
mdiobus_free(struct mii_bus * bus)664 void mdiobus_free(struct mii_bus *bus)
665 {
666 	/* For compatibility with error handling in drivers. */
667 	if (bus->state == MDIOBUS_ALLOCATED) {
668 		kfree(bus);
669 		return;
670 	}
671 
672 	WARN(bus->state != MDIOBUS_UNREGISTERED,
673 	     "%s: not in UNREGISTERED state\n", bus->id);
674 	bus->state = MDIOBUS_RELEASED;
675 
676 	put_device(&bus->dev);
677 }
678 EXPORT_SYMBOL(mdiobus_free);
679 
680 /**
681  * mdiobus_scan - scan a bus for MDIO devices.
682  * @bus: mii_bus to scan
683  * @addr: address on bus to scan
684  *
685  * This function scans the MDIO bus, looking for devices which can be
686  * identified using a vendor/product ID in registers 2 and 3. Not all
687  * MDIO devices have such registers, but PHY devices typically
688  * do. Hence this function assumes anything found is a PHY, or can be
689  * treated as a PHY. Other MDIO devices, such as switches, will
690  * probably not be found during the scan.
691  */
mdiobus_scan(struct mii_bus * bus,int addr)692 struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
693 {
694 	struct phy_device *phydev = ERR_PTR(-ENODEV);
695 	int err;
696 
697 	switch (bus->probe_capabilities) {
698 	case MDIOBUS_NO_CAP:
699 	case MDIOBUS_C22:
700 		phydev = get_phy_device(bus, addr, false);
701 		break;
702 	case MDIOBUS_C45:
703 		phydev = get_phy_device(bus, addr, true);
704 		break;
705 	case MDIOBUS_C22_C45:
706 		phydev = get_phy_device(bus, addr, false);
707 		if (IS_ERR(phydev))
708 			phydev = get_phy_device(bus, addr, true);
709 		break;
710 	}
711 
712 	if (IS_ERR(phydev))
713 		return phydev;
714 
715 	/*
716 	 * For DT, see if the auto-probed phy has a correspoding child
717 	 * in the bus node, and set the of_node pointer in this case.
718 	 */
719 	of_mdiobus_link_mdiodev(bus, &phydev->mdio);
720 
721 	err = phy_device_register(phydev);
722 	if (err) {
723 		phy_device_free(phydev);
724 		return ERR_PTR(-ENODEV);
725 	}
726 
727 	return phydev;
728 }
729 EXPORT_SYMBOL(mdiobus_scan);
730 
mdiobus_stats_acct(struct mdio_bus_stats * stats,bool op,int ret)731 static void mdiobus_stats_acct(struct mdio_bus_stats *stats, bool op, int ret)
732 {
733 	preempt_disable();
734 	u64_stats_update_begin(&stats->syncp);
735 
736 	u64_stats_inc(&stats->transfers);
737 	if (ret < 0) {
738 		u64_stats_inc(&stats->errors);
739 		goto out;
740 	}
741 
742 	if (op)
743 		u64_stats_inc(&stats->reads);
744 	else
745 		u64_stats_inc(&stats->writes);
746 out:
747 	u64_stats_update_end(&stats->syncp);
748 	preempt_enable();
749 }
750 
751 /**
752  * __mdiobus_read - Unlocked version of the mdiobus_read function
753  * @bus: the mii_bus struct
754  * @addr: the phy address
755  * @regnum: register number to read
756  *
757  * Read a MDIO bus register. Caller must hold the mdio bus lock.
758  *
759  * NOTE: MUST NOT be called from interrupt context.
760  */
__mdiobus_read(struct mii_bus * bus,int addr,u32 regnum)761 int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
762 {
763 	int retval;
764 
765 	lockdep_assert_held_once(&bus->mdio_lock);
766 
767 	retval = bus->read(bus, addr, regnum);
768 
769 	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
770 	mdiobus_stats_acct(&bus->stats[addr], true, retval);
771 
772 	return retval;
773 }
774 EXPORT_SYMBOL(__mdiobus_read);
775 
776 /**
777  * __mdiobus_write - Unlocked version of the mdiobus_write function
778  * @bus: the mii_bus struct
779  * @addr: the phy address
780  * @regnum: register number to write
781  * @val: value to write to @regnum
782  *
783  * Write a MDIO bus register. Caller must hold the mdio bus lock.
784  *
785  * NOTE: MUST NOT be called from interrupt context.
786  */
__mdiobus_write(struct mii_bus * bus,int addr,u32 regnum,u16 val)787 int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
788 {
789 	int err;
790 
791 	lockdep_assert_held_once(&bus->mdio_lock);
792 
793 	err = bus->write(bus, addr, regnum, val);
794 
795 	trace_mdio_access(bus, 0, addr, regnum, val, err);
796 	mdiobus_stats_acct(&bus->stats[addr], false, err);
797 
798 	return err;
799 }
800 EXPORT_SYMBOL(__mdiobus_write);
801 
802 /**
803  * __mdiobus_modify_changed - Unlocked version of the mdiobus_modify function
804  * @bus: the mii_bus struct
805  * @addr: the phy address
806  * @regnum: register number to modify
807  * @mask: bit mask of bits to clear
808  * @set: bit mask of bits to set
809  *
810  * Read, modify, and if any change, write the register value back to the
811  * device. Any error returns a negative number.
812  *
813  * NOTE: MUST NOT be called from interrupt context.
814  */
__mdiobus_modify_changed(struct mii_bus * bus,int addr,u32 regnum,u16 mask,u16 set)815 int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
816 			     u16 mask, u16 set)
817 {
818 	int new, ret;
819 
820 	ret = __mdiobus_read(bus, addr, regnum);
821 	if (ret < 0)
822 		return ret;
823 
824 	new = (ret & ~mask) | set;
825 	if (new == ret)
826 		return 0;
827 
828 	ret = __mdiobus_write(bus, addr, regnum, new);
829 
830 	return ret < 0 ? ret : 1;
831 }
832 EXPORT_SYMBOL_GPL(__mdiobus_modify_changed);
833 
834 /**
835  * mdiobus_read_nested - Nested version of the mdiobus_read function
836  * @bus: the mii_bus struct
837  * @addr: the phy address
838  * @regnum: register number to read
839  *
840  * In case of nested MDIO bus access avoid lockdep false positives by
841  * using mutex_lock_nested().
842  *
843  * NOTE: MUST NOT be called from interrupt context,
844  * because the bus read/write functions may wait for an interrupt
845  * to conclude the operation.
846  */
mdiobus_read_nested(struct mii_bus * bus,int addr,u32 regnum)847 int mdiobus_read_nested(struct mii_bus *bus, int addr, u32 regnum)
848 {
849 	int retval;
850 
851 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
852 	retval = __mdiobus_read(bus, addr, regnum);
853 	mutex_unlock(&bus->mdio_lock);
854 
855 	return retval;
856 }
857 EXPORT_SYMBOL(mdiobus_read_nested);
858 
859 /**
860  * mdiobus_read - Convenience function for reading a given MII mgmt register
861  * @bus: the mii_bus struct
862  * @addr: the phy address
863  * @regnum: register number to read
864  *
865  * NOTE: MUST NOT be called from interrupt context,
866  * because the bus read/write functions may wait for an interrupt
867  * to conclude the operation.
868  */
mdiobus_read(struct mii_bus * bus,int addr,u32 regnum)869 int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
870 {
871 	int retval;
872 
873 	mutex_lock(&bus->mdio_lock);
874 	retval = __mdiobus_read(bus, addr, regnum);
875 	mutex_unlock(&bus->mdio_lock);
876 
877 	return retval;
878 }
879 EXPORT_SYMBOL(mdiobus_read);
880 
881 /**
882  * mdiobus_write_nested - Nested version of the mdiobus_write function
883  * @bus: the mii_bus struct
884  * @addr: the phy address
885  * @regnum: register number to write
886  * @val: value to write to @regnum
887  *
888  * In case of nested MDIO bus access avoid lockdep false positives by
889  * using mutex_lock_nested().
890  *
891  * NOTE: MUST NOT be called from interrupt context,
892  * because the bus read/write functions may wait for an interrupt
893  * to conclude the operation.
894  */
mdiobus_write_nested(struct mii_bus * bus,int addr,u32 regnum,u16 val)895 int mdiobus_write_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val)
896 {
897 	int err;
898 
899 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
900 	err = __mdiobus_write(bus, addr, regnum, val);
901 	mutex_unlock(&bus->mdio_lock);
902 
903 	return err;
904 }
905 EXPORT_SYMBOL(mdiobus_write_nested);
906 
907 /**
908  * mdiobus_write - Convenience function for writing a given MII mgmt register
909  * @bus: the mii_bus struct
910  * @addr: the phy address
911  * @regnum: register number to write
912  * @val: value to write to @regnum
913  *
914  * NOTE: MUST NOT be called from interrupt context,
915  * because the bus read/write functions may wait for an interrupt
916  * to conclude the operation.
917  */
mdiobus_write(struct mii_bus * bus,int addr,u32 regnum,u16 val)918 int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
919 {
920 	int err;
921 
922 	mutex_lock(&bus->mdio_lock);
923 	err = __mdiobus_write(bus, addr, regnum, val);
924 	mutex_unlock(&bus->mdio_lock);
925 
926 	return err;
927 }
928 EXPORT_SYMBOL(mdiobus_write);
929 
930 /**
931  * mdiobus_modify - Convenience function for modifying a given mdio device
932  *	register
933  * @bus: the mii_bus struct
934  * @addr: the phy address
935  * @regnum: register number to write
936  * @mask: bit mask of bits to clear
937  * @set: bit mask of bits to set
938  */
mdiobus_modify(struct mii_bus * bus,int addr,u32 regnum,u16 mask,u16 set)939 int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask, u16 set)
940 {
941 	int err;
942 
943 	mutex_lock(&bus->mdio_lock);
944 	err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
945 	mutex_unlock(&bus->mdio_lock);
946 
947 	return err < 0 ? err : 0;
948 }
949 EXPORT_SYMBOL_GPL(mdiobus_modify);
950 
951 /**
952  * mdiobus_modify_changed - Convenience function for modifying a given mdio
953  *	device register and returning if it changed
954  * @bus: the mii_bus struct
955  * @addr: the phy address
956  * @regnum: register number to write
957  * @mask: bit mask of bits to clear
958  * @set: bit mask of bits to set
959  */
mdiobus_modify_changed(struct mii_bus * bus,int addr,u32 regnum,u16 mask,u16 set)960 int mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
961 			   u16 mask, u16 set)
962 {
963 	int err;
964 
965 	mutex_lock(&bus->mdio_lock);
966 	err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
967 	mutex_unlock(&bus->mdio_lock);
968 
969 	return err;
970 }
971 EXPORT_SYMBOL_GPL(mdiobus_modify_changed);
972 
973 /**
974  * mdio_bus_match - determine if given MDIO driver supports the given
975  *		    MDIO device
976  * @dev: target MDIO device
977  * @drv: given MDIO driver
978  *
979  * Description: Given a MDIO device, and a MDIO driver, return 1 if
980  *   the driver supports the device.  Otherwise, return 0. This may
981  *   require calling the devices own match function, since different classes
982  *   of MDIO devices have different match criteria.
983  */
mdio_bus_match(struct device * dev,struct device_driver * drv)984 static int mdio_bus_match(struct device *dev, struct device_driver *drv)
985 {
986 	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
987 	struct mdio_device *mdio = to_mdio_device(dev);
988 
989 	/* Both the driver and device must type-match */
990 	if (!(mdiodrv->mdiodrv.flags & MDIO_DEVICE_IS_PHY) !=
991 	    !(mdio->flags & MDIO_DEVICE_FLAG_PHY))
992 		return 0;
993 
994 	if (of_driver_match_device(dev, drv))
995 		return 1;
996 
997 	if (mdio->bus_match)
998 		return mdio->bus_match(dev, drv);
999 
1000 	return 0;
1001 }
1002 
mdio_uevent(struct device * dev,struct kobj_uevent_env * env)1003 static int mdio_uevent(struct device *dev, struct kobj_uevent_env *env)
1004 {
1005 	int rc;
1006 
1007 	/* Some devices have extra OF data and an OF-style MODALIAS */
1008 	rc = of_device_uevent_modalias(dev, env);
1009 	if (rc != -ENODEV)
1010 		return rc;
1011 
1012 	return 0;
1013 }
1014 
1015 static struct attribute *mdio_bus_device_statistics_attrs[] = {
1016 	&dev_attr_mdio_bus_device_transfers.attr.attr,
1017 	&dev_attr_mdio_bus_device_errors.attr.attr,
1018 	&dev_attr_mdio_bus_device_writes.attr.attr,
1019 	&dev_attr_mdio_bus_device_reads.attr.attr,
1020 	NULL,
1021 };
1022 
1023 static const struct attribute_group mdio_bus_device_statistics_group = {
1024 	.name	= "statistics",
1025 	.attrs	= mdio_bus_device_statistics_attrs,
1026 };
1027 
1028 static const struct attribute_group *mdio_bus_dev_groups[] = {
1029 	&mdio_bus_device_statistics_group,
1030 	NULL,
1031 };
1032 
1033 struct bus_type mdio_bus_type = {
1034 	.name		= "mdio_bus",
1035 	.dev_groups	= mdio_bus_dev_groups,
1036 	.match		= mdio_bus_match,
1037 	.uevent		= mdio_uevent,
1038 };
1039 EXPORT_SYMBOL(mdio_bus_type);
1040 
mdio_bus_init(void)1041 int __init mdio_bus_init(void)
1042 {
1043 	int ret;
1044 
1045 	ret = class_register(&mdio_bus_class);
1046 	if (!ret) {
1047 		ret = bus_register(&mdio_bus_type);
1048 		if (ret)
1049 			class_unregister(&mdio_bus_class);
1050 	}
1051 
1052 	return ret;
1053 }
1054 
1055 #if IS_ENABLED(CONFIG_PHYLIB)
mdio_bus_exit(void)1056 void mdio_bus_exit(void)
1057 {
1058 	class_unregister(&mdio_bus_class);
1059 	bus_unregister(&mdio_bus_type);
1060 }
1061 EXPORT_SYMBOL_GPL(mdio_bus_exit);
1062 #else
1063 module_init(mdio_bus_init);
1064 /* no module_exit, intentional */
1065 MODULE_LICENSE("GPL");
1066 MODULE_DESCRIPTION("MDIO bus/device layer");
1067 #endif
1068