1 /*
2  * QorIQ 10G MDIO Controller
3  *
4  * Copyright 2012 Freescale Semiconductor, Inc.
5  *
6  * Authors: Andy Fleming <afleming@freescale.com>
7  *          Timur Tabi <timur@freescale.com>
8  *
9  * This file is licensed under the terms of the GNU General Public License
10  * version 2.  This program is licensed "as is" without any warranty of any
11  * kind, whether express or implied.
12  */
13 
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/interrupt.h>
17 #include <linux/module.h>
18 #include <linux/phy.h>
19 #include <linux/mdio.h>
20 #include <linux/of_address.h>
21 #include <linux/of_platform.h>
22 #include <linux/of_mdio.h>
23 
24 /* Number of microseconds to wait for a register to respond */
25 #define TIMEOUT	1000
26 
27 struct tgec_mdio_controller {
28 	__be32	reserved[12];
29 	__be32	mdio_stat;	/* MDIO configuration and status */
30 	__be32	mdio_ctl;	/* MDIO control */
31 	__be32	mdio_data;	/* MDIO data */
32 	__be32	mdio_addr;	/* MDIO address */
33 } __packed;
34 
35 #define MDIO_STAT_ENC		BIT(6)
36 #define MDIO_STAT_CLKDIV(x)	(((x>>1) & 0xff) << 8)
37 #define MDIO_STAT_BSY		BIT(0)
38 #define MDIO_STAT_RD_ER		BIT(1)
39 #define MDIO_CTL_DEV_ADDR(x) 	(x & 0x1f)
40 #define MDIO_CTL_PORT_ADDR(x)	((x & 0x1f) << 5)
41 #define MDIO_CTL_PRE_DIS	BIT(10)
42 #define MDIO_CTL_SCAN_EN	BIT(11)
43 #define MDIO_CTL_POST_INC	BIT(14)
44 #define MDIO_CTL_READ		BIT(15)
45 
46 #define MDIO_DATA(x)		(x & 0xffff)
47 #define MDIO_DATA_BSY		BIT(31)
48 
49 struct mdio_fsl_priv {
50 	struct	tgec_mdio_controller __iomem *mdio_base;
51 	bool	is_little_endian;
52 };
53 
54 static u32 xgmac_read32(void __iomem *regs,
55 			bool is_little_endian)
56 {
57 	if (is_little_endian)
58 		return ioread32(regs);
59 	else
60 		return ioread32be(regs);
61 }
62 
63 static void xgmac_write32(u32 value,
64 			  void __iomem *regs,
65 			  bool is_little_endian)
66 {
67 	if (is_little_endian)
68 		iowrite32(value, regs);
69 	else
70 		iowrite32be(value, regs);
71 }
72 
73 /*
74  * Wait until the MDIO bus is free
75  */
76 static int xgmac_wait_until_free(struct device *dev,
77 				 struct tgec_mdio_controller __iomem *regs,
78 				 bool is_little_endian)
79 {
80 	unsigned int timeout;
81 
82 	/* Wait till the bus is free */
83 	timeout = TIMEOUT;
84 	while ((xgmac_read32(&regs->mdio_stat, is_little_endian) &
85 		MDIO_STAT_BSY) && timeout) {
86 		cpu_relax();
87 		timeout--;
88 	}
89 
90 	if (!timeout) {
91 		dev_err(dev, "timeout waiting for bus to be free\n");
92 		return -ETIMEDOUT;
93 	}
94 
95 	return 0;
96 }
97 
98 /*
99  * Wait till the MDIO read or write operation is complete
100  */
101 static int xgmac_wait_until_done(struct device *dev,
102 				 struct tgec_mdio_controller __iomem *regs,
103 				 bool is_little_endian)
104 {
105 	unsigned int timeout;
106 
107 	/* Wait till the MDIO write is complete */
108 	timeout = TIMEOUT;
109 	while ((xgmac_read32(&regs->mdio_stat, is_little_endian) &
110 		MDIO_STAT_BSY) && timeout) {
111 		cpu_relax();
112 		timeout--;
113 	}
114 
115 	if (!timeout) {
116 		dev_err(dev, "timeout waiting for operation to complete\n");
117 		return -ETIMEDOUT;
118 	}
119 
120 	return 0;
121 }
122 
123 /*
124  * Write value to the PHY for this device to the register at regnum,waiting
125  * until the write is done before it returns.  All PHY configuration has to be
126  * done through the TSEC1 MIIM regs.
127  */
128 static int xgmac_mdio_write(struct mii_bus *bus, int phy_id, int regnum, u16 value)
129 {
130 	struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
131 	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
132 	uint16_t dev_addr;
133 	u32 mdio_ctl, mdio_stat;
134 	int ret;
135 	bool endian = priv->is_little_endian;
136 
137 	mdio_stat = xgmac_read32(&regs->mdio_stat, endian);
138 	if (regnum & MII_ADDR_C45) {
139 		/* Clause 45 (ie 10G) */
140 		dev_addr = (regnum >> 16) & 0x1f;
141 		mdio_stat |= MDIO_STAT_ENC;
142 	} else {
143 		/* Clause 22 (ie 1G) */
144 		dev_addr = regnum & 0x1f;
145 		mdio_stat &= ~MDIO_STAT_ENC;
146 	}
147 
148 	xgmac_write32(mdio_stat, &regs->mdio_stat, endian);
149 
150 	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
151 	if (ret)
152 		return ret;
153 
154 	/* Set the port and dev addr */
155 	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) | MDIO_CTL_DEV_ADDR(dev_addr);
156 	xgmac_write32(mdio_ctl, &regs->mdio_ctl, endian);
157 
158 	/* Set the register address */
159 	if (regnum & MII_ADDR_C45) {
160 		xgmac_write32(regnum & 0xffff, &regs->mdio_addr, endian);
161 
162 		ret = xgmac_wait_until_free(&bus->dev, regs, endian);
163 		if (ret)
164 			return ret;
165 	}
166 
167 	/* Write the value to the register */
168 	xgmac_write32(MDIO_DATA(value), &regs->mdio_data, endian);
169 
170 	ret = xgmac_wait_until_done(&bus->dev, regs, endian);
171 	if (ret)
172 		return ret;
173 
174 	return 0;
175 }
176 
177 /*
178  * Reads from register regnum in the PHY for device dev, returning the value.
179  * Clears miimcom first.  All PHY configuration has to be done through the
180  * TSEC1 MIIM regs.
181  */
182 static int xgmac_mdio_read(struct mii_bus *bus, int phy_id, int regnum)
183 {
184 	struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
185 	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
186 	uint16_t dev_addr;
187 	uint32_t mdio_stat;
188 	uint32_t mdio_ctl;
189 	uint16_t value;
190 	int ret;
191 	bool endian = priv->is_little_endian;
192 
193 	mdio_stat = xgmac_read32(&regs->mdio_stat, endian);
194 	if (regnum & MII_ADDR_C45) {
195 		dev_addr = (regnum >> 16) & 0x1f;
196 		mdio_stat |= MDIO_STAT_ENC;
197 	} else {
198 		dev_addr = regnum & 0x1f;
199 		mdio_stat &= ~MDIO_STAT_ENC;
200 	}
201 
202 	xgmac_write32(mdio_stat, &regs->mdio_stat, endian);
203 
204 	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
205 	if (ret)
206 		return ret;
207 
208 	/* Set the Port and Device Addrs */
209 	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) | MDIO_CTL_DEV_ADDR(dev_addr);
210 	xgmac_write32(mdio_ctl, &regs->mdio_ctl, endian);
211 
212 	/* Set the register address */
213 	if (regnum & MII_ADDR_C45) {
214 		xgmac_write32(regnum & 0xffff, &regs->mdio_addr, endian);
215 
216 		ret = xgmac_wait_until_free(&bus->dev, regs, endian);
217 		if (ret)
218 			return ret;
219 	}
220 
221 	/* Initiate the read */
222 	xgmac_write32(mdio_ctl | MDIO_CTL_READ, &regs->mdio_ctl, endian);
223 
224 	ret = xgmac_wait_until_done(&bus->dev, regs, endian);
225 	if (ret)
226 		return ret;
227 
228 	/* Return all Fs if nothing was there */
229 	if (xgmac_read32(&regs->mdio_stat, endian) & MDIO_STAT_RD_ER) {
230 		dev_err(&bus->dev,
231 			"Error while reading PHY%d reg at %d.%hhu\n",
232 			phy_id, dev_addr, regnum);
233 		return 0xffff;
234 	}
235 
236 	value = xgmac_read32(&regs->mdio_data, endian) & 0xffff;
237 	dev_dbg(&bus->dev, "read %04x\n", value);
238 
239 	return value;
240 }
241 
242 static int xgmac_mdio_probe(struct platform_device *pdev)
243 {
244 	struct device_node *np = pdev->dev.of_node;
245 	struct mii_bus *bus;
246 	struct resource res;
247 	struct mdio_fsl_priv *priv;
248 	int ret;
249 
250 	ret = of_address_to_resource(np, 0, &res);
251 	if (ret) {
252 		dev_err(&pdev->dev, "could not obtain address\n");
253 		return ret;
254 	}
255 
256 	bus = mdiobus_alloc_size(sizeof(struct mdio_fsl_priv));
257 	if (!bus)
258 		return -ENOMEM;
259 
260 	bus->name = "Freescale XGMAC MDIO Bus";
261 	bus->read = xgmac_mdio_read;
262 	bus->write = xgmac_mdio_write;
263 	bus->parent = &pdev->dev;
264 	snprintf(bus->id, MII_BUS_ID_SIZE, "%llx", (unsigned long long)res.start);
265 
266 	/* Set the PHY base address */
267 	priv = bus->priv;
268 	priv->mdio_base = of_iomap(np, 0);
269 	if (!priv->mdio_base) {
270 		ret = -ENOMEM;
271 		goto err_ioremap;
272 	}
273 
274 	if (of_get_property(pdev->dev.of_node,
275 			    "little-endian", NULL))
276 		priv->is_little_endian = true;
277 	else
278 		priv->is_little_endian = false;
279 
280 	ret = of_mdiobus_register(bus, np);
281 	if (ret) {
282 		dev_err(&pdev->dev, "cannot register MDIO bus\n");
283 		goto err_registration;
284 	}
285 
286 	platform_set_drvdata(pdev, bus);
287 
288 	return 0;
289 
290 err_registration:
291 	iounmap(priv->mdio_base);
292 
293 err_ioremap:
294 	mdiobus_free(bus);
295 
296 	return ret;
297 }
298 
299 static int xgmac_mdio_remove(struct platform_device *pdev)
300 {
301 	struct mii_bus *bus = platform_get_drvdata(pdev);
302 
303 	mdiobus_unregister(bus);
304 	iounmap(bus->priv);
305 	mdiobus_free(bus);
306 
307 	return 0;
308 }
309 
310 static const struct of_device_id xgmac_mdio_match[] = {
311 	{
312 		.compatible = "fsl,fman-xmdio",
313 	},
314 	{
315 		.compatible = "fsl,fman-memac-mdio",
316 	},
317 	{},
318 };
319 MODULE_DEVICE_TABLE(of, xgmac_mdio_match);
320 
321 static struct platform_driver xgmac_mdio_driver = {
322 	.driver = {
323 		.name = "fsl-fman_xmdio",
324 		.of_match_table = xgmac_mdio_match,
325 	},
326 	.probe = xgmac_mdio_probe,
327 	.remove = xgmac_mdio_remove,
328 };
329 
330 module_platform_driver(xgmac_mdio_driver);
331 
332 MODULE_DESCRIPTION("Freescale QorIQ 10G MDIO Controller");
333 MODULE_LICENSE("GPL v2");
334