mdio_bus_provider.c

  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(&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(-ENODEV);
136	struct fwnode_handle *fwnode;
137	char node_name[16];
138	int err;
139
140	phydev = get_phy_device(bus, addr, c45);
141	if (IS_ERR(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(node_name, sizeof(node_name), "ethernet-phy@%d",
156			 addr);
157		fwnode = fwnode_get_named_child_node(dev_fwnode(&bus->dev),
158						     node_name);
159		if (fwnode)
160			device_set_node(&phydev->mdio.dev, fwnode);
161	}
162
163	err = phy_device_register(phydev);
164	if (err) {
165		phy_device_free(phydev);
166		return ERR_PTR(-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, 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, 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(phydev) && (PTR_ERR(phydev) != -ENODEV))
217				return PTR_ERR(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, i);
236			if (IS_ERR(phydev) && (PTR_ERR(phydev) != -ENODEV))
237				return PTR_ERR(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	struct phy_device *phydev;
253
254	mdiobus_for_each_phy(bus, phydev) {
255		u32 oui = phydev->phy_id >> 10;
256
257		if (oui == MICREL_OUI)
258			return true;
259	}
260
261	return false;
262}
263
264/**
265 * __mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
266 * @bus: target mii_bus
267 * @owner: module containing bus accessor functions
268 *
269 * Description: Called by a bus driver to bring up all the PHYs
270 *   on a given bus, and attach them to the bus. Drivers should use
271 *   mdiobus_register() rather than __mdiobus_register() unless they
272 *   need to pass a specific owner module. MDIO devices which are not
273 *   PHYs will not be brought up by this function. They are expected
274 *   to be explicitly listed in DT and instantiated by of_mdiobus_register().
275 *
276 * Returns 0 on success or < 0 on error.
277 */
278int __mdiobus_register(struct mii_bus *bus, struct module *owner)
279{
280	struct mdio_device *mdiodev;
281	struct gpio_desc *gpiod;
282	bool prevent_c45_scan;
283	int i, err;
284
285	if (!bus || !bus->name)
286		return -EINVAL;
287
288	/* An access method always needs both read and write operations */
289	if (!!bus->read != !!bus->write || !!bus->read_c45 != !!bus->write_c45)
290		return -EINVAL;
291
292	/* At least one method is mandatory */
293	if (!bus->read && !bus->read_c45)
294		return -EINVAL;
295
296	if (bus->parent && bus->parent->of_node)
297		bus->parent->of_node->fwnode.flags |=
298					FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD;
299
300	WARN(bus->state != MDIOBUS_ALLOCATED &&
301	     bus->state != MDIOBUS_UNREGISTERED,
302	     "%s: not in ALLOCATED or UNREGISTERED state\n", bus->id);
303
304	bus->owner = owner;
305	bus->dev.parent = bus->parent;
306	bus->dev.class = &mdio_bus_class;
307	bus->dev.groups = NULL;
308	dev_set_name(&bus->dev, "%s", bus->id);
309
310	/* If the bus state is allocated, we're registering a fresh bus
311	 * that may have a fwnode associated with it. Grab a reference
312	 * to the fwnode. This will be dropped when the bus is released.
313	 * If the bus was set to unregistered, it means that the bus was
314	 * previously registered, and we've already grabbed a reference.
315	 */
316	if (bus->state == MDIOBUS_ALLOCATED)
317		fwnode_handle_get(dev_fwnode(&bus->dev));
318
319	/* We need to set state to MDIOBUS_UNREGISTERED to correctly release
320	 * the device in mdiobus_free()
321	 *
322	 * State will be updated later in this function in case of success
323	 */
324	bus->state = MDIOBUS_UNREGISTERED;
325
326	err = device_register(&bus->dev);
327	if (err) {
328		pr_err("mii_bus %s failed to register\n", bus->id);
329		return -EINVAL;
330	}
331
332	mutex_init(&bus->mdio_lock);
333	mutex_init(&bus->shared_lock);
334
335	/* assert bus level PHY GPIO reset */
336	gpiod = devm_gpiod_get_optional(&bus->dev, "reset", GPIOD_OUT_HIGH);
337	if (IS_ERR(gpiod)) {
338		err = dev_err_probe(&bus->dev, PTR_ERR(gpiod),
339				    "mii_bus %s couldn't get reset GPIO\n",
340				    bus->id);
341		device_del(&bus->dev);
342		return err;
343	} else	if (gpiod) {
344		bus->reset_gpiod = gpiod;
345		fsleep(bus->reset_delay_us);
346		gpiod_set_value_cansleep(gpiod, 0);
347		if (bus->reset_post_delay_us > 0)
348			fsleep(bus->reset_post_delay_us);
349	}
350
351	if (bus->reset) {
352		err = bus->reset(bus);
353		if (err)
354			goto error_reset_gpiod;
355	}
356
357	if (bus->read) {
358		err = mdiobus_scan_bus_c22(bus);
359		if (err)
360			goto error;
361	}
362
363	prevent_c45_scan = mdiobus_prevent_c45_scan(bus);
364
365	if (!prevent_c45_scan && bus->read_c45) {
366		err = mdiobus_scan_bus_c45(bus);
367		if (err)
368			goto error;
369	}
370
371	bus->state = MDIOBUS_REGISTERED;
372	dev_dbg(&bus->dev, "probed\n");
373	return 0;
374
375error:
376	for (i = 0; i < PHY_MAX_ADDR; i++) {
377		mdiodev = bus->mdio_map[i];
378		if (!mdiodev)
379			continue;
380
381		mdiodev->device_remove(mdiodev);
382		mdiodev->device_free(mdiodev);
383	}
384error_reset_gpiod:
385	/* Put PHYs in RESET to save power */
386	if (bus->reset_gpiod)
387		gpiod_set_value_cansleep(bus->reset_gpiod, 1);
388
389	device_del(&bus->dev);
390	return err;
391}
392EXPORT_SYMBOL(__mdiobus_register);
393
394void mdiobus_unregister(struct mii_bus *bus)
395{
396	struct mdio_device *mdiodev;
397	int i;
398
399	if (WARN_ON_ONCE(bus->state != MDIOBUS_REGISTERED))
400		return;
401	bus->state = MDIOBUS_UNREGISTERED;
402
403	for (i = 0; i < PHY_MAX_ADDR; i++) {
404		mdiodev = bus->mdio_map[i];
405		if (!mdiodev)
406			continue;
407
408		mdiodev->device_remove(mdiodev);
409		mdiodev->device_free(mdiodev);
410	}
411
412	/* Put PHYs in RESET to save power */
413	if (bus->reset_gpiod)
414		gpiod_set_value_cansleep(bus->reset_gpiod, 1);
415
416	device_del(&bus->dev);
417}
418EXPORT_SYMBOL(mdiobus_unregister);
419
420/**
421 * mdiobus_free - free a struct mii_bus
422 * @bus: mii_bus to free
423 *
424 * This function releases the reference to the underlying device
425 * object in the mii_bus.  If this is the last reference, the mii_bus
426 * will be freed.
427 */
428void mdiobus_free(struct mii_bus *bus)
429{
430	/* For compatibility with error handling in drivers. */
431	if (bus->state == MDIOBUS_ALLOCATED) {
432		kfree(bus);
433		return;
434	}
435
436	WARN(bus->state != MDIOBUS_UNREGISTERED,
437	     "%s: not in UNREGISTERED state\n", bus->id);
438	bus->state = MDIOBUS_RELEASED;
439
440	put_device(&bus->dev);
441}
442EXPORT_SYMBOL(mdiobus_free);