1/*
  2 * Fixed MDIO bus (MDIO bus emulation with fixed PHYs)
  3 *
  4 * Author: Vitaly Bordug <vbordug@ru.mvista.com>
  5 *         Anton Vorontsov <avorontsov@ru.mvista.com>
  6 *
  7 * Copyright (c) 2006-2007 MontaVista Software, Inc.
  8 *
  9 * This program is free software; you can redistribute  it and/or modify it
 10 * under  the terms of  the GNU General  Public License as published by the
 11 * Free Software Foundation;  either version 2 of the  License, or (at your
 12 * option) any later version.
 13 */
 14
 15#include <linux/kernel.h>
 16#include <linux/module.h>
 17#include <linux/platform_device.h>
 18#include <linux/list.h>
 19#include <linux/mii.h>
 20#include <linux/phy.h>
 21#include <linux/phy_fixed.h>
 22#include <linux/err.h>
 23#include <linux/slab.h>
 24#include <linux/of.h>
 25#include <linux/gpio.h>
 26#include <linux/seqlock.h>
 27#include <linux/idr.h>
 28
 29#include "swphy.h"
 30
 31struct fixed_mdio_bus {
 32	struct mii_bus *mii_bus;
 33	struct list_head phys;
 34};
 35
 36struct fixed_phy {
 37	int addr;
 38	struct phy_device *phydev;
 39	seqcount_t seqcount;
 40	struct fixed_phy_status status;
 41	int (*link_update)(struct net_device *, struct fixed_phy_status *);
 42	struct list_head node;
 43	int link_gpio;
 44};
 45
 46static struct platform_device *pdev;
 47static struct fixed_mdio_bus platform_fmb = {
 48	.phys = LIST_HEAD_INIT(platform_fmb.phys),
 49};
 50
 51static void fixed_phy_update(struct fixed_phy *fp)
 52{
 53	if (gpio_is_valid(fp->link_gpio))
 54		fp->status.link = !!gpio_get_value_cansleep(fp->link_gpio);
 55}
 56
 57static int fixed_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
 58{
 59	struct fixed_mdio_bus *fmb = bus->priv;
 60	struct fixed_phy *fp;
 61
 62	list_for_each_entry(fp, &fmb->phys, node) {
 63		if (fp->addr == phy_addr) {
 64			struct fixed_phy_status state;
 65			int s;
 66
 67			do {
 68				s = read_seqcount_begin(&fp->seqcount);
 69				/* Issue callback if user registered it. */
 70				if (fp->link_update) {
 71					fp->link_update(fp->phydev->attached_dev,
 72							&fp->status);
 73					fixed_phy_update(fp);
 74				}
 75				state = fp->status;
 76			} while (read_seqcount_retry(&fp->seqcount, s));
 77
 78			return swphy_read_reg(reg_num, &state);
 79		}
 80	}
 81
 82	return 0xFFFF;
 83}
 84
 85static int fixed_mdio_write(struct mii_bus *bus, int phy_addr, int reg_num,
 86			    u16 val)
 87{
 88	return 0;
 89}
 90
 91/*
 92 * If something weird is required to be done with link/speed,
 93 * network driver is able to assign a function to implement this.
 94 * May be useful for PHY's that need to be software-driven.
 95 */
 96int fixed_phy_set_link_update(struct phy_device *phydev,
 97			      int (*link_update)(struct net_device *,
 98						 struct fixed_phy_status *))
 99{
100	struct fixed_mdio_bus *fmb = &platform_fmb;
101	struct fixed_phy *fp;
102
103	if (!phydev || !phydev->mdio.bus)
104		return -EINVAL;
105
106	list_for_each_entry(fp, &fmb->phys, node) {
107		if (fp->addr == phydev->mdio.addr) {
108			fp->link_update = link_update;
109			fp->phydev = phydev;
110			return 0;
111		}
112	}
113
114	return -ENOENT;
115}
116EXPORT_SYMBOL_GPL(fixed_phy_set_link_update);
117
118int fixed_phy_update_state(struct phy_device *phydev,
119			   const struct fixed_phy_status *status,
120			   const struct fixed_phy_status *changed)
121{
122	struct fixed_mdio_bus *fmb = &platform_fmb;
123	struct fixed_phy *fp;
124
125	if (!phydev || phydev->mdio.bus != fmb->mii_bus)
126		return -EINVAL;
127
128	list_for_each_entry(fp, &fmb->phys, node) {
129		if (fp->addr == phydev->mdio.addr) {
130			write_seqcount_begin(&fp->seqcount);
131#define _UPD(x) if (changed->x) \
132	fp->status.x = status->x
133			_UPD(link);
134			_UPD(speed);
135			_UPD(duplex);
136			_UPD(pause);
137			_UPD(asym_pause);
138#undef _UPD
139			fixed_phy_update(fp);
140			write_seqcount_end(&fp->seqcount);
141			return 0;
142		}
143	}
144
145	return -ENOENT;
146}
147EXPORT_SYMBOL(fixed_phy_update_state);
148
149int fixed_phy_add(unsigned int irq, int phy_addr,
150		  struct fixed_phy_status *status,
151		  int link_gpio)
152{
153	int ret;
154	struct fixed_mdio_bus *fmb = &platform_fmb;
155	struct fixed_phy *fp;
156
157	ret = swphy_validate_state(status);
158	if (ret < 0)
159		return ret;
160
161	fp = kzalloc(sizeof(*fp), GFP_KERNEL);
162	if (!fp)
163		return -ENOMEM;
164
165	seqcount_init(&fp->seqcount);
166
167	if (irq != PHY_POLL)
168		fmb->mii_bus->irq[phy_addr] = irq;
169
170	fp->addr = phy_addr;
171	fp->status = *status;
172	fp->link_gpio = link_gpio;
173
174	if (gpio_is_valid(fp->link_gpio)) {
175		ret = gpio_request_one(fp->link_gpio, GPIOF_DIR_IN,
176				       "fixed-link-gpio-link");
177		if (ret)
178			goto err_regs;
179	}
180
181	fixed_phy_update(fp);
182
183	list_add_tail(&fp->node, &fmb->phys);
184
185	return 0;
186
187err_regs:
188	kfree(fp);
189	return ret;
190}
191EXPORT_SYMBOL_GPL(fixed_phy_add);
192
193static DEFINE_IDA(phy_fixed_ida);
194
195static void fixed_phy_del(int phy_addr)
196{
197	struct fixed_mdio_bus *fmb = &platform_fmb;
198	struct fixed_phy *fp, *tmp;
199
200	list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
201		if (fp->addr == phy_addr) {
202			list_del(&fp->node);
203			if (gpio_is_valid(fp->link_gpio))
204				gpio_free(fp->link_gpio);
205			kfree(fp);
206			ida_simple_remove(&phy_fixed_ida, phy_addr);
207			return;
208		}
209	}
210}
211
212struct phy_device *fixed_phy_register(unsigned int irq,
213				      struct fixed_phy_status *status,
214				      int link_gpio,
215				      struct device_node *np)
216{
217	struct fixed_mdio_bus *fmb = &platform_fmb;
218	struct phy_device *phy;
219	int phy_addr;
220	int ret;
221
222	if (!fmb->mii_bus || fmb->mii_bus->state != MDIOBUS_REGISTERED)
223		return ERR_PTR(-EPROBE_DEFER);
224
225	/* Get the next available PHY address, up to PHY_MAX_ADDR */
226	phy_addr = ida_simple_get(&phy_fixed_ida, 0, PHY_MAX_ADDR, GFP_KERNEL);
227	if (phy_addr < 0)
228		return ERR_PTR(phy_addr);
229
230	ret = fixed_phy_add(irq, phy_addr, status, link_gpio);
231	if (ret < 0) {
232		ida_simple_remove(&phy_fixed_ida, phy_addr);
233		return ERR_PTR(ret);
234	}
235
236	phy = get_phy_device(fmb->mii_bus, phy_addr, false);
237	if (IS_ERR(phy)) {
238		fixed_phy_del(phy_addr);
239		return ERR_PTR(-EINVAL);
240	}
241
242	/* propagate the fixed link values to struct phy_device */
243	phy->link = status->link;
244	if (status->link) {
245		phy->speed = status->speed;
246		phy->duplex = status->duplex;
247		phy->pause = status->pause;
248		phy->asym_pause = status->asym_pause;
249	}
250
251	of_node_get(np);
252	phy->mdio.dev.of_node = np;
253	phy->is_pseudo_fixed_link = true;
254
255	switch (status->speed) {
256	case SPEED_1000:
257		phy->supported = PHY_1000BT_FEATURES;
258		break;
259	case SPEED_100:
260		phy->supported = PHY_100BT_FEATURES;
261		break;
262	case SPEED_10:
263	default:
264		phy->supported = PHY_10BT_FEATURES;
265	}
266
267	ret = phy_device_register(phy);
268	if (ret) {
269		phy_device_free(phy);
270		of_node_put(np);
271		fixed_phy_del(phy_addr);
272		return ERR_PTR(ret);
273	}
274
275	return phy;
276}
277EXPORT_SYMBOL_GPL(fixed_phy_register);
278
279void fixed_phy_unregister(struct phy_device *phy)
280{
281	phy_device_remove(phy);
282	of_node_put(phy->mdio.dev.of_node);
283	fixed_phy_del(phy->mdio.addr);
284}
285EXPORT_SYMBOL_GPL(fixed_phy_unregister);
286
287static int __init fixed_mdio_bus_init(void)
288{
289	struct fixed_mdio_bus *fmb = &platform_fmb;
290	int ret;
291
292	pdev = platform_device_register_simple("Fixed MDIO bus", 0, NULL, 0);
293	if (IS_ERR(pdev)) {
294		ret = PTR_ERR(pdev);
295		goto err_pdev;
296	}
297
298	fmb->mii_bus = mdiobus_alloc();
299	if (fmb->mii_bus == NULL) {
300		ret = -ENOMEM;
301		goto err_mdiobus_reg;
302	}
303
304	snprintf(fmb->mii_bus->id, MII_BUS_ID_SIZE, "fixed-0");
305	fmb->mii_bus->name = "Fixed MDIO Bus";
306	fmb->mii_bus->priv = fmb;
307	fmb->mii_bus->parent = &pdev->dev;
308	fmb->mii_bus->read = &fixed_mdio_read;
309	fmb->mii_bus->write = &fixed_mdio_write;
310
311	ret = mdiobus_register(fmb->mii_bus);
312	if (ret)
313		goto err_mdiobus_alloc;
314
315	return 0;
316
317err_mdiobus_alloc:
318	mdiobus_free(fmb->mii_bus);
319err_mdiobus_reg:
320	platform_device_unregister(pdev);
321err_pdev:
322	return ret;
323}
324module_init(fixed_mdio_bus_init);
325
326static void __exit fixed_mdio_bus_exit(void)
327{
328	struct fixed_mdio_bus *fmb = &platform_fmb;
329	struct fixed_phy *fp, *tmp;
330
331	mdiobus_unregister(fmb->mii_bus);
332	mdiobus_free(fmb->mii_bus);
333	platform_device_unregister(pdev);
334
335	list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
336		list_del(&fp->node);
337		kfree(fp);
338	}
339	ida_destroy(&phy_fixed_ida);
340}
341module_exit(fixed_mdio_bus_exit);
342
343MODULE_DESCRIPTION("Fixed MDIO bus (MDIO bus emulation with fixed PHYs)");
344MODULE_AUTHOR("Vitaly Bordug");
345MODULE_LICENSE("GPL");