1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Fixed MDIO bus (MDIO bus emulation with fixed PHYs)
4 *
5 * Author: Vitaly Bordug <vbordug@ru.mvista.com>
6 *         Anton Vorontsov <avorontsov@ru.mvista.com>
7 *
8 * Copyright (c) 2006-2007 MontaVista Software, Inc.
9 */
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/platform_device.h>
14#include <linux/list.h>
15#include <linux/mii.h>
16#include <linux/phy.h>
17#include <linux/phy_fixed.h>
18#include <linux/err.h>
19#include <linux/slab.h>
20#include <linux/of.h>
21#include <linux/gpio/consumer.h>
22#include <linux/idr.h>
23#include <linux/netdevice.h>
24#include <linux/linkmode.h>
25
26#include "swphy.h"
27
28struct fixed_mdio_bus {
29	struct mii_bus *mii_bus;
30	struct list_head phys;
31};
32
33struct fixed_phy {
34	int addr;
35	struct phy_device *phydev;
36	struct fixed_phy_status status;
37	bool no_carrier;
38	int (*link_update)(struct net_device *, struct fixed_phy_status *);
39	struct list_head node;
40	struct gpio_desc *link_gpiod;
41};
42
43static struct platform_device *pdev;
44static struct fixed_mdio_bus platform_fmb = {
45	.phys = LIST_HEAD_INIT(platform_fmb.phys),
46};
47
48int fixed_phy_change_carrier(struct net_device *dev, bool new_carrier)
49{
50	struct fixed_mdio_bus *fmb = &platform_fmb;
51	struct phy_device *phydev = dev->phydev;
52	struct fixed_phy *fp;
53
54	if (!phydev || !phydev->mdio.bus)
55		return -EINVAL;
56
57	list_for_each_entry(fp, &fmb->phys, node) {
58		if (fp->addr == phydev->mdio.addr) {
59			fp->no_carrier = !new_carrier;
60			return 0;
61		}
62	}
63	return -EINVAL;
64}
65EXPORT_SYMBOL_GPL(fixed_phy_change_carrier);
66
67static void fixed_phy_update(struct fixed_phy *fp)
68{
69	if (!fp->no_carrier && fp->link_gpiod)
70		fp->status.link = !!gpiod_get_value_cansleep(fp->link_gpiod);
71}
72
73static int fixed_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
74{
75	struct fixed_mdio_bus *fmb = bus->priv;
76	struct fixed_phy *fp;
77
78	list_for_each_entry(fp, &fmb->phys, node) {
79		if (fp->addr == phy_addr) {
80			struct fixed_phy_status state;
81
82			fp->status.link = !fp->no_carrier;
83
84			/* Issue callback if user registered it. */
85			if (fp->link_update)
86				fp->link_update(fp->phydev->attached_dev,
87						&fp->status);
88
89			/* Check the GPIO for change in status */
90			fixed_phy_update(fp);
91			state = fp->status;
92
93			return swphy_read_reg(reg_num, &state);
94		}
95	}
96
97	return 0xFFFF;
98}
99
100static int fixed_mdio_write(struct mii_bus *bus, int phy_addr, int reg_num,
101			    u16 val)
102{
103	return 0;
104}
105
106/*
107 * If something weird is required to be done with link/speed,
108 * network driver is able to assign a function to implement this.
109 * May be useful for PHY's that need to be software-driven.
110 */
111int fixed_phy_set_link_update(struct phy_device *phydev,
112			      int (*link_update)(struct net_device *,
113						 struct fixed_phy_status *))
114{
115	struct fixed_mdio_bus *fmb = &platform_fmb;
116	struct fixed_phy *fp;
117
118	if (!phydev || !phydev->mdio.bus)
119		return -EINVAL;
120
121	list_for_each_entry(fp, &fmb->phys, node) {
122		if (fp->addr == phydev->mdio.addr) {
123			fp->link_update = link_update;
124			fp->phydev = phydev;
125			return 0;
126		}
127	}
128
129	return -ENOENT;
130}
131EXPORT_SYMBOL_GPL(fixed_phy_set_link_update);
132
133static int fixed_phy_add_gpiod(unsigned int irq, int phy_addr,
134			       struct fixed_phy_status *status,
135			       struct gpio_desc *gpiod)
136{
137	int ret;
138	struct fixed_mdio_bus *fmb = &platform_fmb;
139	struct fixed_phy *fp;
140
141	ret = swphy_validate_state(status);
142	if (ret < 0)
143		return ret;
144
145	fp = kzalloc(sizeof(*fp), GFP_KERNEL);
146	if (!fp)
147		return -ENOMEM;
148
149	if (irq != PHY_POLL)
150		fmb->mii_bus->irq[phy_addr] = irq;
151
152	fp->addr = phy_addr;
153	fp->status = *status;
154	fp->link_gpiod = gpiod;
155
156	fixed_phy_update(fp);
157
158	list_add_tail(&fp->node, &fmb->phys);
159
160	return 0;
161}
162
163int fixed_phy_add(unsigned int irq, int phy_addr,
164		  struct fixed_phy_status *status)
165{
166	return fixed_phy_add_gpiod(irq, phy_addr, status, NULL);
167}
168EXPORT_SYMBOL_GPL(fixed_phy_add);
169
170static DEFINE_IDA(phy_fixed_ida);
171
172static void fixed_phy_del(int phy_addr)
173{
174	struct fixed_mdio_bus *fmb = &platform_fmb;
175	struct fixed_phy *fp, *tmp;
176
177	list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
178		if (fp->addr == phy_addr) {
179			list_del(&fp->node);
180			if (fp->link_gpiod)
181				gpiod_put(fp->link_gpiod);
182			kfree(fp);
183			ida_free(&phy_fixed_ida, phy_addr);
184			return;
185		}
186	}
187}
188
189#ifdef CONFIG_OF_GPIO
190static struct gpio_desc *fixed_phy_get_gpiod(struct device_node *np)
191{
192	struct device_node *fixed_link_node;
193	struct gpio_desc *gpiod;
194
195	if (!np)
196		return NULL;
197
198	fixed_link_node = of_get_child_by_name(np, "fixed-link");
199	if (!fixed_link_node)
200		return NULL;
201
202	/*
203	 * As the fixed link is just a device tree node without any
204	 * Linux device associated with it, we simply have obtain
205	 * the GPIO descriptor from the device tree like this.
206	 */
207	gpiod = fwnode_gpiod_get_index(of_fwnode_handle(fixed_link_node),
208				       "link", 0, GPIOD_IN, "mdio");
209	if (IS_ERR(gpiod) && PTR_ERR(gpiod) != -EPROBE_DEFER) {
210		if (PTR_ERR(gpiod) != -ENOENT)
211			pr_err("error getting GPIO for fixed link %pOF, proceed without\n",
212			       fixed_link_node);
213		gpiod = NULL;
214	}
215	of_node_put(fixed_link_node);
216
217	return gpiod;
218}
219#else
220static struct gpio_desc *fixed_phy_get_gpiod(struct device_node *np)
221{
222	return NULL;
223}
224#endif
225
226static struct phy_device *__fixed_phy_register(unsigned int irq,
227					       struct fixed_phy_status *status,
228					       struct device_node *np,
229					       struct gpio_desc *gpiod)
230{
231	struct fixed_mdio_bus *fmb = &platform_fmb;
232	struct phy_device *phy;
233	int phy_addr;
234	int ret;
235
236	if (!fmb->mii_bus || fmb->mii_bus->state != MDIOBUS_REGISTERED)
237		return ERR_PTR(-EPROBE_DEFER);
238
239	/* Check if we have a GPIO associated with this fixed phy */
240	if (!gpiod) {
241		gpiod = fixed_phy_get_gpiod(np);
242		if (IS_ERR(gpiod))
243			return ERR_CAST(gpiod);
244	}
245
246	/* Get the next available PHY address, up to PHY_MAX_ADDR */
247	phy_addr = ida_alloc_max(&phy_fixed_ida, PHY_MAX_ADDR - 1, GFP_KERNEL);
248	if (phy_addr < 0)
249		return ERR_PTR(phy_addr);
250
251	ret = fixed_phy_add_gpiod(irq, phy_addr, status, gpiod);
252	if (ret < 0) {
253		ida_free(&phy_fixed_ida, phy_addr);
254		return ERR_PTR(ret);
255	}
256
257	phy = get_phy_device(fmb->mii_bus, phy_addr, false);
258	if (IS_ERR(phy)) {
259		fixed_phy_del(phy_addr);
260		return ERR_PTR(-EINVAL);
261	}
262
263	/* propagate the fixed link values to struct phy_device */
264	phy->link = status->link;
265	if (status->link) {
266		phy->speed = status->speed;
267		phy->duplex = status->duplex;
268		phy->pause = status->pause;
269		phy->asym_pause = status->asym_pause;
270	}
271
272	of_node_get(np);
273	phy->mdio.dev.of_node = np;
274	phy->is_pseudo_fixed_link = true;
275
276	switch (status->speed) {
277	case SPEED_1000:
278		linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Half_BIT,
279				 phy->supported);
280		linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Full_BIT,
281				 phy->supported);
282		fallthrough;
283	case SPEED_100:
284		linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Half_BIT,
285				 phy->supported);
286		linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Full_BIT,
287				 phy->supported);
288		fallthrough;
289	case SPEED_10:
290	default:
291		linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT_Half_BIT,
292				 phy->supported);
293		linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT_Full_BIT,
294				 phy->supported);
295	}
296
297	phy_advertise_supported(phy);
298
299	ret = phy_device_register(phy);
300	if (ret) {
301		phy_device_free(phy);
302		of_node_put(np);
303		fixed_phy_del(phy_addr);
304		return ERR_PTR(ret);
305	}
306
307	return phy;
308}
309
310struct phy_device *fixed_phy_register(unsigned int irq,
311				      struct fixed_phy_status *status,
312				      struct device_node *np)
313{
314	return __fixed_phy_register(irq, status, np, NULL);
315}
316EXPORT_SYMBOL_GPL(fixed_phy_register);
317
318struct phy_device *
319fixed_phy_register_with_gpiod(unsigned int irq,
320			      struct fixed_phy_status *status,
321			      struct gpio_desc *gpiod)
322{
323	return __fixed_phy_register(irq, status, NULL, gpiod);
324}
325EXPORT_SYMBOL_GPL(fixed_phy_register_with_gpiod);
326
327void fixed_phy_unregister(struct phy_device *phy)
328{
329	phy_device_remove(phy);
330	of_node_put(phy->mdio.dev.of_node);
331	fixed_phy_del(phy->mdio.addr);
332}
333EXPORT_SYMBOL_GPL(fixed_phy_unregister);
334
335static int __init fixed_mdio_bus_init(void)
336{
337	struct fixed_mdio_bus *fmb = &platform_fmb;
338	int ret;
339
340	pdev = platform_device_register_simple("Fixed MDIO bus", 0, NULL, 0);
341	if (IS_ERR(pdev))
342		return PTR_ERR(pdev);
343
344	fmb->mii_bus = mdiobus_alloc();
345	if (fmb->mii_bus == NULL) {
346		ret = -ENOMEM;
347		goto err_mdiobus_reg;
348	}
349
350	snprintf(fmb->mii_bus->id, MII_BUS_ID_SIZE, "fixed-0");
351	fmb->mii_bus->name = "Fixed MDIO Bus";
352	fmb->mii_bus->priv = fmb;
353	fmb->mii_bus->parent = &pdev->dev;
354	fmb->mii_bus->read = &fixed_mdio_read;
355	fmb->mii_bus->write = &fixed_mdio_write;
356	fmb->mii_bus->phy_mask = ~0;
357
358	ret = mdiobus_register(fmb->mii_bus);
359	if (ret)
360		goto err_mdiobus_alloc;
361
362	return 0;
363
364err_mdiobus_alloc:
365	mdiobus_free(fmb->mii_bus);
366err_mdiobus_reg:
367	platform_device_unregister(pdev);
368	return ret;
369}
370module_init(fixed_mdio_bus_init);
371
372static void __exit fixed_mdio_bus_exit(void)
373{
374	struct fixed_mdio_bus *fmb = &platform_fmb;
375	struct fixed_phy *fp, *tmp;
376
377	mdiobus_unregister(fmb->mii_bus);
378	mdiobus_free(fmb->mii_bus);
379	platform_device_unregister(pdev);
380
381	list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
382		list_del(&fp->node);
383		kfree(fp);
384	}
385	ida_destroy(&phy_fixed_ida);
386}
387module_exit(fixed_mdio_bus_exit);
388
389MODULE_DESCRIPTION("Fixed MDIO bus (MDIO bus emulation with fixed PHYs)");
390MODULE_AUTHOR("Vitaly Bordug");
391MODULE_LICENSE("GPL");
392