1// SPDX-License-Identifier: GPL-2.0+
2/* MDIO Bus provider 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/consumer.h>
17#include <linux/init.h>
18#include <linux/io.h>
19#include <linux/kernel.h>
20#include <linux/micrel_phy.h>
21#include <linux/mii.h>
22#include <linux/mm.h>
23#include <linux/netdevice.h>
24#include <linux/of_device.h>
25#include <linux/of_mdio.h>
26#include <linux/phy.h>
27#include <linux/slab.h>
28#include <linux/string.h>
29#include <linux/uaccess.h>
30#include <linux/unistd.h>
31
32/**
33 * mdiobus_alloc_size - allocate a mii_bus structure
34 * @size: extra amount of memory to allocate for private storage.
35 * If non-zero, then bus->priv is points to that memory.
36 *
37 * Description: called by a bus driver to allocate an mii_bus
38 * structure to fill in.
39 */
40struct mii_bus *mdiobus_alloc_size(size_t size)
41{
42 struct mii_bus *bus;
43 size_t aligned_size = ALIGN(sizeof(*bus), NETDEV_ALIGN);
44 size_t alloc_size;
45 int i;
46
47 /* If we alloc extra space, it should be aligned */
48 if (size)
49 alloc_size = aligned_size + size;
50 else
51 alloc_size = sizeof(*bus);
52
53 bus = kzalloc(alloc_size, GFP_KERNEL);
54 if (!bus)
55 return NULL;
56
57 bus->state = MDIOBUS_ALLOCATED;
58 if (size)
59 bus->priv = (void *)bus + aligned_size;
60
61 /* Initialise the interrupts to polling and 64-bit seqcounts */
62 for (i = 0; i < PHY_MAX_ADDR; i++) {
63 bus->irq[i] = PHY_POLL;
64 u64_stats_init(syncp: &bus->stats[i].syncp);
65 }
66
67 return bus;
68}
69EXPORT_SYMBOL(mdiobus_alloc_size);
70
71#if IS_ENABLED(CONFIG_OF_MDIO)
72/* Walk the list of subnodes of a mdio bus and look for a node that
73 * matches the mdio device's address with its 'reg' property. If
74 * found, set the of_node pointer for the mdio device. This allows
75 * auto-probed phy devices to be supplied with information passed in
76 * via DT.
77 * If a PHY package is found, PHY is searched also there.
78 */
79static int of_mdiobus_find_phy(struct device *dev, struct mdio_device *mdiodev,
80 struct device_node *np)
81{
82 struct device_node *child;
83
84 for_each_available_child_of_node(np, child) {
85 int addr;
86
87 if (of_node_name_eq(child, "ethernet-phy-package")) {
88 /* Validate PHY package reg presence */
89 if (!of_property_present(child, "reg")) {
90 of_node_put(child);
91 return -EINVAL;
92 }
93
94 if (!of_mdiobus_find_phy(dev, mdiodev, child)) {
95 /* The refcount for the PHY package will be
96 * incremented later when PHY join the Package.
97 */
98 of_node_put(child);
99 return 0;
100 }
101
102 continue;
103 }
104
105 addr = of_mdio_parse_addr(dev, child);
106 if (addr < 0)
107 continue;
108
109 if (addr == mdiodev->addr) {
110 device_set_node(dev, of_fwnode_handle(child));
111 /* The refcount on "child" is passed to the mdio
112 * device. Do _not_ use of_node_put(child) here.
113 */
114 return 0;
115 }
116 }
117
118 return -ENODEV;
119}
120
121static void of_mdiobus_link_mdiodev(struct mii_bus *bus,
122 struct mdio_device *mdiodev)
123{
124 struct device *dev = &mdiodev->dev;
125
126 if (dev->of_node || !bus->dev.of_node)
127 return;
128
129 of_mdiobus_find_phy(dev, mdiodev, bus->dev.of_node);
130}
131#endif
132
133static struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr, bool c45)
134{
135 struct phy_device *phydev = ERR_PTR(error: -ENODEV);
136 struct fwnode_handle *fwnode;
137 char node_name[16];
138 int err;
139
140 phydev = get_phy_device(bus, addr, is_c45: c45);
141 if (IS_ERR(ptr: phydev))
142 return phydev;
143
144#if IS_ENABLED(CONFIG_OF_MDIO)
145 /* For DT, see if the auto-probed phy has a corresponding child
146 * in the bus node, and set the of_node pointer in this case.
147 */
148 of_mdiobus_link_mdiodev(bus, &phydev->mdio);
149#endif
150
151 /* Search for a swnode for the phy in the swnode hierarchy of the bus.
152 * If there is no swnode for the phy provided, just ignore it.
153 */
154 if (dev_fwnode(&bus->dev) && !dev_fwnode(&phydev->mdio.dev)) {
155 snprintf(buf: node_name, size: sizeof(node_name), fmt: "ethernet-phy@%d",
156 addr);
157 fwnode = fwnode_get_named_child_node(dev_fwnode(&bus->dev),
158 childname: node_name);
159 if (fwnode)
160 device_set_node(dev: &phydev->mdio.dev, fwnode);
161 }
162
163 err = phy_device_register(phy: phydev);
164 if (err) {
165 phy_device_free(phydev);
166 return ERR_PTR(error: -ENODEV);
167 }
168
169 return phydev;
170}
171
172/**
173 * mdiobus_scan_c22 - scan one address on a bus for C22 MDIO devices.
174 * @bus: mii_bus to scan
175 * @addr: address on bus to scan
176 *
177 * This function scans one address on the MDIO bus, looking for
178 * devices which can be identified using a vendor/product ID in
179 * registers 2 and 3. Not all MDIO devices have such registers, but
180 * PHY devices typically do. Hence this function assumes anything
181 * found is a PHY, or can be treated as a PHY. Other MDIO devices,
182 * such as switches, will probably not be found during the scan.
183 */
184struct phy_device *mdiobus_scan_c22(struct mii_bus *bus, int addr)
185{
186 return mdiobus_scan(bus, addr, c45: false);
187}
188EXPORT_SYMBOL(mdiobus_scan_c22);
189
190/**
191 * mdiobus_scan_c45 - scan one address on a bus for C45 MDIO devices.
192 * @bus: mii_bus to scan
193 * @addr: address on bus to scan
194 *
195 * This function scans one address on the MDIO bus, looking for
196 * devices which can be identified using a vendor/product ID in
197 * registers 2 and 3. Not all MDIO devices have such registers, but
198 * PHY devices typically do. Hence this function assumes anything
199 * found is a PHY, or can be treated as a PHY. Other MDIO devices,
200 * such as switches, will probably not be found during the scan.
201 */
202static struct phy_device *mdiobus_scan_c45(struct mii_bus *bus, int addr)
203{
204 return mdiobus_scan(bus, addr, c45: true);
205}
206
207static int mdiobus_scan_bus_c22(struct mii_bus *bus)
208{
209 int i;
210
211 for (i = 0; i < PHY_MAX_ADDR; i++) {
212 if ((bus->phy_mask & BIT(i)) == 0) {
213 struct phy_device *phydev;
214
215 phydev = mdiobus_scan_c22(bus, i);
216 if (IS_ERR(ptr: phydev) && (PTR_ERR(ptr: phydev) != -ENODEV))
217 return PTR_ERR(ptr: phydev);
218 }
219 }
220 return 0;
221}
222
223static int mdiobus_scan_bus_c45(struct mii_bus *bus)
224{
225 int i;
226
227 for (i = 0; i < PHY_MAX_ADDR; i++) {
228 if ((bus->phy_mask & BIT(i)) == 0) {
229 struct phy_device *phydev;
230
231 /* Don't scan C45 if we already have a C22 device */
232 if (bus->mdio_map[i])
233 continue;
234
235 phydev = mdiobus_scan_c45(bus, addr: i);
236 if (IS_ERR(ptr: phydev) && (PTR_ERR(ptr: phydev) != -ENODEV))
237 return PTR_ERR(ptr: phydev);
238 }
239 }
240 return 0;
241}
242
243/* There are some C22 PHYs which do bad things when where is a C45
244 * transaction on the bus, like accepting a read themselves, and
245 * stomping over the true devices reply, to performing a write to
246 * themselves which was intended for another device. Now that C22
247 * devices have been found, see if any of them are bad for C45, and if we
248 * should skip the C45 scan.
249 */
250static bool mdiobus_prevent_c45_scan(struct mii_bus *bus)
251{
252 int i;
253
254 for (i = 0; i < PHY_MAX_ADDR; i++) {
255 struct phy_device *phydev;
256 u32 oui;
257
258 phydev = mdiobus_get_phy(bus, addr: i);
259 if (!phydev)
260 continue;
261 oui = phydev->phy_id >> 10;
262
263 if (oui == MICREL_OUI)
264 return true;
265 }
266 return false;
267}
268
269/**
270 * __mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
271 * @bus: target mii_bus
272 * @owner: module containing bus accessor functions
273 *
274 * Description: Called by a bus driver to bring up all the PHYs
275 * on a given bus, and attach them to the bus. Drivers should use
276 * mdiobus_register() rather than __mdiobus_register() unless they
277 * need to pass a specific owner module. MDIO devices which are not
278 * PHYs will not be brought up by this function. They are expected
279 * to be explicitly listed in DT and instantiated by of_mdiobus_register().
280 *
281 * Returns 0 on success or < 0 on error.
282 */
283int __mdiobus_register(struct mii_bus *bus, struct module *owner)
284{
285 struct mdio_device *mdiodev;
286 struct gpio_desc *gpiod;
287 bool prevent_c45_scan;
288 int i, err;
289
290 if (!bus || !bus->name)
291 return -EINVAL;
292
293 /* An access method always needs both read and write operations */
294 if (!!bus->read != !!bus->write || !!bus->read_c45 != !!bus->write_c45)
295 return -EINVAL;
296
297 /* At least one method is mandatory */
298 if (!bus->read && !bus->read_c45)
299 return -EINVAL;
300
301 if (bus->parent && bus->parent->of_node)
302 bus->parent->of_node->fwnode.flags |=
303 FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD;
304
305 WARN(bus->state != MDIOBUS_ALLOCATED &&
306 bus->state != MDIOBUS_UNREGISTERED,
307 "%s: not in ALLOCATED or UNREGISTERED state\n", bus->id);
308
309 bus->owner = owner;
310 bus->dev.parent = bus->parent;
311 bus->dev.class = &mdio_bus_class;
312 bus->dev.groups = NULL;
313 dev_set_name(dev: &bus->dev, name: "%s", bus->id);
314
315 /* If the bus state is allocated, we're registering a fresh bus
316 * that may have a fwnode associated with it. Grab a reference
317 * to the fwnode. This will be dropped when the bus is released.
318 * If the bus was set to unregistered, it means that the bus was
319 * previously registered, and we've already grabbed a reference.
320 */
321 if (bus->state == MDIOBUS_ALLOCATED)
322 fwnode_handle_get(dev_fwnode(&bus->dev));
323
324 /* We need to set state to MDIOBUS_UNREGISTERED to correctly release
325 * the device in mdiobus_free()
326 *
327 * State will be updated later in this function in case of success
328 */
329 bus->state = MDIOBUS_UNREGISTERED;
330
331 err = device_register(dev: &bus->dev);
332 if (err) {
333 pr_err("mii_bus %s failed to register\n", bus->id);
334 return -EINVAL;
335 }
336
337 mutex_init(&bus->mdio_lock);
338 mutex_init(&bus->shared_lock);
339
340 /* assert bus level PHY GPIO reset */
341 gpiod = devm_gpiod_get_optional(dev: &bus->dev, con_id: "reset", flags: GPIOD_OUT_HIGH);
342 if (IS_ERR(ptr: gpiod)) {
343 err = dev_err_probe(dev: &bus->dev, err: PTR_ERR(ptr: gpiod),
344 fmt: "mii_bus %s couldn't get reset GPIO\n",
345 bus->id);
346 device_del(dev: &bus->dev);
347 return err;
348 } else if (gpiod) {
349 bus->reset_gpiod = gpiod;
350 fsleep(usecs: bus->reset_delay_us);
351 gpiod_set_value_cansleep(desc: gpiod, value: 0);
352 if (bus->reset_post_delay_us > 0)
353 fsleep(usecs: bus->reset_post_delay_us);
354 }
355
356 if (bus->reset) {
357 err = bus->reset(bus);
358 if (err)
359 goto error_reset_gpiod;
360 }
361
362 if (bus->read) {
363 err = mdiobus_scan_bus_c22(bus);
364 if (err)
365 goto error;
366 }
367
368 prevent_c45_scan = mdiobus_prevent_c45_scan(bus);
369
370 if (!prevent_c45_scan && bus->read_c45) {
371 err = mdiobus_scan_bus_c45(bus);
372 if (err)
373 goto error;
374 }
375
376 bus->state = MDIOBUS_REGISTERED;
377 dev_dbg(&bus->dev, "probed\n");
378 return 0;
379
380error:
381 for (i = 0; i < PHY_MAX_ADDR; i++) {
382 mdiodev = bus->mdio_map[i];
383 if (!mdiodev)
384 continue;
385
386 mdiodev->device_remove(mdiodev);
387 mdiodev->device_free(mdiodev);
388 }
389error_reset_gpiod:
390 /* Put PHYs in RESET to save power */
391 if (bus->reset_gpiod)
392 gpiod_set_value_cansleep(desc: bus->reset_gpiod, value: 1);
393
394 device_del(dev: &bus->dev);
395 return err;
396}
397EXPORT_SYMBOL(__mdiobus_register);
398
399void mdiobus_unregister(struct mii_bus *bus)
400{
401 struct mdio_device *mdiodev;
402 int i;
403
404 if (WARN_ON_ONCE(bus->state != MDIOBUS_REGISTERED))
405 return;
406 bus->state = MDIOBUS_UNREGISTERED;
407
408 for (i = 0; i < PHY_MAX_ADDR; i++) {
409 mdiodev = bus->mdio_map[i];
410 if (!mdiodev)
411 continue;
412
413 mdiodev->device_remove(mdiodev);
414 mdiodev->device_free(mdiodev);
415 }
416
417 /* Put PHYs in RESET to save power */
418 if (bus->reset_gpiod)
419 gpiod_set_value_cansleep(desc: bus->reset_gpiod, value: 1);
420
421 device_del(dev: &bus->dev);
422}
423EXPORT_SYMBOL(mdiobus_unregister);
424
425/**
426 * mdiobus_free - free a struct mii_bus
427 * @bus: mii_bus to free
428 *
429 * This function releases the reference to the underlying device
430 * object in the mii_bus. If this is the last reference, the mii_bus
431 * will be freed.
432 */
433void mdiobus_free(struct mii_bus *bus)
434{
435 /* For compatibility with error handling in drivers. */
436 if (bus->state == MDIOBUS_ALLOCATED) {
437 kfree(objp: bus);
438 return;
439 }
440
441 WARN(bus->state != MDIOBUS_UNREGISTERED,
442 "%s: not in UNREGISTERED state\n", bus->id);
443 bus->state = MDIOBUS_RELEASED;
444
445 put_device(dev: &bus->dev);
446}
447EXPORT_SYMBOL(mdiobus_free);
448