1/*
  2 * Copyright 2016 Broadcom
  3 *
  4 * This program is free software; you can redistribute it and/or modify
  5 * it under the terms of the GNU General Public License, version 2, as
  6 * published by the Free Software Foundation (the "GPL").
  7 *
  8 * This program is distributed in the hope that it will be useful, but
  9 * WITHOUT ANY WARRANTY; without even the implied warranty of
 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 11 * General Public License version 2 (GPLv2) for more details.
 12 *
 13 * You should have received a copy of the GNU General Public License
 14 * version 2 (GPLv2) along with this source code.
 15 */
 16
 17#include <linux/platform_device.h>
 18#include <linux/device.h>
 19#include <linux/of_mdio.h>
 20#include <linux/module.h>
 21#include <linux/phy.h>
 22#include <linux/mdio-mux.h>
 23#include <linux/delay.h>
 24
 25#define MDIO_PARAM_OFFSET		0x00
 26#define MDIO_PARAM_MIIM_CYCLE		29
 27#define MDIO_PARAM_INTERNAL_SEL		25
 28#define MDIO_PARAM_BUS_ID		22
 29#define MDIO_PARAM_C45_SEL		21
 30#define MDIO_PARAM_PHY_ID		16
 31#define MDIO_PARAM_PHY_DATA		0
 32
 33#define MDIO_READ_OFFSET		0x04
 34#define MDIO_READ_DATA_MASK		0xffff
 35#define MDIO_ADDR_OFFSET		0x08
 36
 37#define MDIO_CTRL_OFFSET		0x0C
 38#define MDIO_CTRL_WRITE_OP		0x1
 39#define MDIO_CTRL_READ_OP		0x2
 40
 41#define MDIO_STAT_OFFSET		0x10
 42#define MDIO_STAT_DONE			1
 43
 44#define BUS_MAX_ADDR			32
 45#define EXT_BUS_START_ADDR		16
 46
 47struct iproc_mdiomux_desc {
 48	void *mux_handle;
 49	void __iomem *base;
 50	struct device *dev;
 51	struct mii_bus *mii_bus;
 52};
 53
 54static int iproc_mdio_wait_for_idle(void __iomem *base, bool result)
 55{
 56	unsigned int timeout = 1000; /* loop for 1s */
 57	u32 val;
 58
 59	do {
 60		val = readl(base + MDIO_STAT_OFFSET);
 61		if ((val & MDIO_STAT_DONE) == result)
 62			return 0;
 63
 64		usleep_range(1000, 2000);
 65	} while (timeout--);
 66
 67	return -ETIMEDOUT;
 68}
 69
 70/* start_miim_ops- Program and start MDIO transaction over mdio bus.
 71 * @base: Base address
 72 * @phyid: phyid of the selected bus.
 73 * @reg: register offset to be read/written.
 74 * @val :0 if read op else value to be written in @reg;
 75 * @op: Operation that need to be carried out.
 76 *      MDIO_CTRL_READ_OP: Read transaction.
 77 *      MDIO_CTRL_WRITE_OP: Write transaction.
 78 *
 79 * Return value: Successful Read operation returns read reg values and write
 80 *      operation returns 0. Failure operation returns negative error code.
 81 */
 82static int start_miim_ops(void __iomem *base,
 83			  u16 phyid, u32 reg, u16 val, u32 op)
 84{
 85	u32 param;
 86	int ret;
 87
 88	writel(0, base + MDIO_CTRL_OFFSET);
 89	ret = iproc_mdio_wait_for_idle(base, 0);
 90	if (ret)
 91		goto err;
 92
 93	param = readl(base + MDIO_PARAM_OFFSET);
 94	param |= phyid << MDIO_PARAM_PHY_ID;
 95	param |= val << MDIO_PARAM_PHY_DATA;
 96	if (reg & MII_ADDR_C45)
 97		param |= BIT(MDIO_PARAM_C45_SEL);
 98
 99	writel(param, base + MDIO_PARAM_OFFSET);
100
101	writel(reg, base + MDIO_ADDR_OFFSET);
102
103	writel(op, base + MDIO_CTRL_OFFSET);
104
105	ret = iproc_mdio_wait_for_idle(base, 1);
106	if (ret)
107		goto err;
108
109	if (op == MDIO_CTRL_READ_OP)
110		ret = readl(base + MDIO_READ_OFFSET) & MDIO_READ_DATA_MASK;
111err:
112	return ret;
113}
114
115static int iproc_mdiomux_read(struct mii_bus *bus, int phyid, int reg)
116{
117	struct iproc_mdiomux_desc *md = bus->priv;
118	int ret;
119
120	ret = start_miim_ops(md->base, phyid, reg, 0, MDIO_CTRL_READ_OP);
121	if (ret < 0)
122		dev_err(&bus->dev, "mdiomux read operation failed!!!");
123
124	return ret;
125}
126
127static int iproc_mdiomux_write(struct mii_bus *bus,
128			       int phyid, int reg, u16 val)
129{
130	struct iproc_mdiomux_desc *md = bus->priv;
131	int ret;
132
133	/* Write val at reg offset */
134	ret = start_miim_ops(md->base, phyid, reg, val, MDIO_CTRL_WRITE_OP);
135	if (ret < 0)
136		dev_err(&bus->dev, "mdiomux write operation failed!!!");
137
138	return ret;
139}
140
141static int mdio_mux_iproc_switch_fn(int current_child, int desired_child,
142				    void *data)
143{
144	struct iproc_mdiomux_desc *md = data;
145	u32 param, bus_id;
146	bool bus_dir;
147
148	/* select bus and its properties */
149	bus_dir = (desired_child < EXT_BUS_START_ADDR);
150	bus_id = bus_dir ? desired_child : (desired_child - EXT_BUS_START_ADDR);
151
152	param = (bus_dir ? 1 : 0) << MDIO_PARAM_INTERNAL_SEL;
153	param |= (bus_id << MDIO_PARAM_BUS_ID);
154
155	writel(param, md->base + MDIO_PARAM_OFFSET);
156	return 0;
157}
158
159static int mdio_mux_iproc_probe(struct platform_device *pdev)
160{
161	struct iproc_mdiomux_desc *md;
162	struct mii_bus *bus;
163	struct resource *res;
164	int rc;
165
166	md = devm_kzalloc(&pdev->dev, sizeof(*md), GFP_KERNEL);
167	if (!md)
168		return -ENOMEM;
169	md->dev = &pdev->dev;
170
171	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
172	md->base = devm_ioremap_resource(&pdev->dev, res);
173	if (IS_ERR(md->base)) {
174		dev_err(&pdev->dev, "failed to ioremap register\n");
175		return PTR_ERR(md->base);
176	}
177
178	md->mii_bus = mdiobus_alloc();
179	if (!md->mii_bus) {
180		dev_err(&pdev->dev, "mdiomux bus alloc failed\n");
181		return -ENOMEM;
182	}
183
184	bus = md->mii_bus;
185	bus->priv = md;
186	bus->name = "iProc MDIO mux bus";
187	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id);
188	bus->parent = &pdev->dev;
189	bus->read = iproc_mdiomux_read;
190	bus->write = iproc_mdiomux_write;
191
192	bus->phy_mask = ~0;
193	bus->dev.of_node = pdev->dev.of_node;
194	rc = mdiobus_register(bus);
195	if (rc) {
196		dev_err(&pdev->dev, "mdiomux registration failed\n");
197		goto out;
198	}
199
200	platform_set_drvdata(pdev, md);
201
202	rc = mdio_mux_init(md->dev, md->dev->of_node, mdio_mux_iproc_switch_fn,
203			   &md->mux_handle, md, md->mii_bus);
204	if (rc) {
205		dev_info(md->dev, "mdiomux initialization failed\n");
206		goto out_register;
207	}
208
209	dev_info(md->dev, "iProc mdiomux registered\n");
210	return 0;
211
212out_register:
213	mdiobus_unregister(bus);
214out:
215	mdiobus_free(bus);
216	return rc;
217}
218
219static int mdio_mux_iproc_remove(struct platform_device *pdev)
220{
221	struct iproc_mdiomux_desc *md = dev_get_platdata(&pdev->dev);
222
223	mdio_mux_uninit(md->mux_handle);
224	mdiobus_unregister(md->mii_bus);
225	mdiobus_free(md->mii_bus);
226
227	return 0;
228}
229
230static const struct of_device_id mdio_mux_iproc_match[] = {
231	{
232		.compatible = "brcm,mdio-mux-iproc",
233	},
234	{},
235};
236MODULE_DEVICE_TABLE(of, mdio_mux_iproc_match);
237
238static struct platform_driver mdiomux_iproc_driver = {
239	.driver = {
240		.name		= "mdio-mux-iproc",
241		.of_match_table = mdio_mux_iproc_match,
242	},
243	.probe		= mdio_mux_iproc_probe,
244	.remove		= mdio_mux_iproc_remove,
245};
246
247module_platform_driver(mdiomux_iproc_driver);
248
249MODULE_DESCRIPTION("iProc MDIO Mux Bus Driver");
250MODULE_AUTHOR("Pramod Kumar <pramod.kumar@broadcom.com>");
251MODULE_LICENSE("GPL v2");