1 /*
2  * QorIQ 10G MDIO Controller
3  *
4  * Copyright 2012 Freescale Semiconductor, Inc.
5  * Copyright 2021 NXP
6  *
7  * Authors: Andy Fleming <afleming@freescale.com>
8  *          Timur Tabi <timur@freescale.com>
9  *
10  * This file is licensed under the terms of the GNU General Public License
11  * version 2.  This program is licensed "as is" without any warranty of any
12  * kind, whether express or implied.
13  */
14 
15 #include <linux/acpi.h>
16 #include <linux/acpi_mdio.h>
17 #include <linux/interrupt.h>
18 #include <linux/kernel.h>
19 #include <linux/mdio.h>
20 #include <linux/module.h>
21 #include <linux/of_address.h>
22 #include <linux/of_mdio.h>
23 #include <linux/of_platform.h>
24 #include <linux/phy.h>
25 #include <linux/slab.h>
26 
27 /* Number of microseconds to wait for a register to respond */
28 #define TIMEOUT	1000
29 
30 struct tgec_mdio_controller {
31 	__be32	reserved[12];
32 	__be32	mdio_stat;	/* MDIO configuration and status */
33 	__be32	mdio_ctl;	/* MDIO control */
34 	__be32	mdio_data;	/* MDIO data */
35 	__be32	mdio_addr;	/* MDIO address */
36 } __packed;
37 
38 #define MDIO_STAT_ENC		BIT(6)
39 #define MDIO_STAT_CLKDIV(x)	(((x>>1) & 0xff) << 8)
40 #define MDIO_STAT_BSY		BIT(0)
41 #define MDIO_STAT_RD_ER		BIT(1)
42 #define MDIO_CTL_DEV_ADDR(x) 	(x & 0x1f)
43 #define MDIO_CTL_PORT_ADDR(x)	((x & 0x1f) << 5)
44 #define MDIO_CTL_PRE_DIS	BIT(10)
45 #define MDIO_CTL_SCAN_EN	BIT(11)
46 #define MDIO_CTL_POST_INC	BIT(14)
47 #define MDIO_CTL_READ		BIT(15)
48 
49 #define MDIO_DATA(x)		(x & 0xffff)
50 
51 struct mdio_fsl_priv {
52 	struct	tgec_mdio_controller __iomem *mdio_base;
53 	bool	is_little_endian;
54 	bool	has_a009885;
55 	bool	has_a011043;
56 };
57 
58 static u32 xgmac_read32(void __iomem *regs,
59 			bool is_little_endian)
60 {
61 	if (is_little_endian)
62 		return ioread32(regs);
63 	else
64 		return ioread32be(regs);
65 }
66 
67 static void xgmac_write32(u32 value,
68 			  void __iomem *regs,
69 			  bool is_little_endian)
70 {
71 	if (is_little_endian)
72 		iowrite32(value, regs);
73 	else
74 		iowrite32be(value, regs);
75 }
76 
77 /*
78  * Wait until the MDIO bus is free
79  */
80 static int xgmac_wait_until_free(struct device *dev,
81 				 struct tgec_mdio_controller __iomem *regs,
82 				 bool is_little_endian)
83 {
84 	unsigned int timeout;
85 
86 	/* Wait till the bus is free */
87 	timeout = TIMEOUT;
88 	while ((xgmac_read32(&regs->mdio_stat, is_little_endian) &
89 		MDIO_STAT_BSY) && timeout) {
90 		cpu_relax();
91 		timeout--;
92 	}
93 
94 	if (!timeout) {
95 		dev_err(dev, "timeout waiting for bus to be free\n");
96 		return -ETIMEDOUT;
97 	}
98 
99 	return 0;
100 }
101 
102 /*
103  * Wait till the MDIO read or write operation is complete
104  */
105 static int xgmac_wait_until_done(struct device *dev,
106 				 struct tgec_mdio_controller __iomem *regs,
107 				 bool is_little_endian)
108 {
109 	unsigned int timeout;
110 
111 	/* Wait till the MDIO write is complete */
112 	timeout = TIMEOUT;
113 	while ((xgmac_read32(&regs->mdio_stat, is_little_endian) &
114 		MDIO_STAT_BSY) && timeout) {
115 		cpu_relax();
116 		timeout--;
117 	}
118 
119 	if (!timeout) {
120 		dev_err(dev, "timeout waiting for operation to complete\n");
121 		return -ETIMEDOUT;
122 	}
123 
124 	return 0;
125 }
126 
127 /*
128  * Write value to the PHY for this device to the register at regnum,waiting
129  * until the write is done before it returns.  All PHY configuration has to be
130  * done through the TSEC1 MIIM regs.
131  */
132 static int xgmac_mdio_write(struct mii_bus *bus, int phy_id, int regnum, u16 value)
133 {
134 	struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
135 	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
136 	uint16_t dev_addr;
137 	u32 mdio_ctl, mdio_stat;
138 	int ret;
139 	bool endian = priv->is_little_endian;
140 
141 	mdio_stat = xgmac_read32(&regs->mdio_stat, endian);
142 	if (regnum & MII_ADDR_C45) {
143 		/* Clause 45 (ie 10G) */
144 		dev_addr = (regnum >> 16) & 0x1f;
145 		mdio_stat |= MDIO_STAT_ENC;
146 	} else {
147 		/* Clause 22 (ie 1G) */
148 		dev_addr = regnum & 0x1f;
149 		mdio_stat &= ~MDIO_STAT_ENC;
150 	}
151 
152 	xgmac_write32(mdio_stat, &regs->mdio_stat, endian);
153 
154 	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
155 	if (ret)
156 		return ret;
157 
158 	/* Set the port and dev addr */
159 	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) | MDIO_CTL_DEV_ADDR(dev_addr);
160 	xgmac_write32(mdio_ctl, &regs->mdio_ctl, endian);
161 
162 	/* Set the register address */
163 	if (regnum & MII_ADDR_C45) {
164 		xgmac_write32(regnum & 0xffff, &regs->mdio_addr, endian);
165 
166 		ret = xgmac_wait_until_free(&bus->dev, regs, endian);
167 		if (ret)
168 			return ret;
169 	}
170 
171 	/* Write the value to the register */
172 	xgmac_write32(MDIO_DATA(value), &regs->mdio_data, endian);
173 
174 	ret = xgmac_wait_until_done(&bus->dev, regs, endian);
175 	if (ret)
176 		return ret;
177 
178 	return 0;
179 }
180 
181 /*
182  * Reads from register regnum in the PHY for device dev, returning the value.
183  * Clears miimcom first.  All PHY configuration has to be done through the
184  * TSEC1 MIIM regs.
185  */
186 static int xgmac_mdio_read(struct mii_bus *bus, int phy_id, int regnum)
187 {
188 	struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
189 	struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
190 	unsigned long flags;
191 	uint16_t dev_addr;
192 	uint32_t mdio_stat;
193 	uint32_t mdio_ctl;
194 	int ret;
195 	bool endian = priv->is_little_endian;
196 
197 	mdio_stat = xgmac_read32(&regs->mdio_stat, endian);
198 	if (regnum & MII_ADDR_C45) {
199 		dev_addr = (regnum >> 16) & 0x1f;
200 		mdio_stat |= MDIO_STAT_ENC;
201 	} else {
202 		dev_addr = regnum & 0x1f;
203 		mdio_stat &= ~MDIO_STAT_ENC;
204 	}
205 
206 	xgmac_write32(mdio_stat, &regs->mdio_stat, endian);
207 
208 	ret = xgmac_wait_until_free(&bus->dev, regs, endian);
209 	if (ret)
210 		return ret;
211 
212 	/* Set the Port and Device Addrs */
213 	mdio_ctl = MDIO_CTL_PORT_ADDR(phy_id) | MDIO_CTL_DEV_ADDR(dev_addr);
214 	xgmac_write32(mdio_ctl, &regs->mdio_ctl, endian);
215 
216 	/* Set the register address */
217 	if (regnum & MII_ADDR_C45) {
218 		xgmac_write32(regnum & 0xffff, &regs->mdio_addr, endian);
219 
220 		ret = xgmac_wait_until_free(&bus->dev, regs, endian);
221 		if (ret)
222 			return ret;
223 	}
224 
225 	if (priv->has_a009885)
226 		/* Once the operation completes, i.e. MDIO_STAT_BSY clears, we
227 		 * must read back the data register within 16 MDC cycles.
228 		 */
229 		local_irq_save(flags);
230 
231 	/* Initiate the read */
232 	xgmac_write32(mdio_ctl | MDIO_CTL_READ, &regs->mdio_ctl, endian);
233 
234 	ret = xgmac_wait_until_done(&bus->dev, regs, endian);
235 	if (ret)
236 		goto irq_restore;
237 
238 	/* Return all Fs if nothing was there */
239 	if ((xgmac_read32(&regs->mdio_stat, endian) & MDIO_STAT_RD_ER) &&
240 	    !priv->has_a011043) {
241 		dev_dbg(&bus->dev,
242 			"Error while reading PHY%d reg at %d.%hhu\n",
243 			phy_id, dev_addr, regnum);
244 		ret = 0xffff;
245 	} else {
246 		ret = xgmac_read32(&regs->mdio_data, endian) & 0xffff;
247 		dev_dbg(&bus->dev, "read %04x\n", ret);
248 	}
249 
250 irq_restore:
251 	if (priv->has_a009885)
252 		local_irq_restore(flags);
253 
254 	return ret;
255 }
256 
257 static int xgmac_mdio_probe(struct platform_device *pdev)
258 {
259 	struct fwnode_handle *fwnode;
260 	struct mdio_fsl_priv *priv;
261 	struct resource *res;
262 	struct mii_bus *bus;
263 	int ret;
264 
265 	/* In DPAA-1, MDIO is one of the many FMan sub-devices. The FMan
266 	 * defines a register space that spans a large area, covering all the
267 	 * subdevice areas. Therefore, MDIO cannot claim exclusive access to
268 	 * this register area.
269 	 */
270 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
271 	if (!res) {
272 		dev_err(&pdev->dev, "could not obtain address\n");
273 		return -EINVAL;
274 	}
275 
276 	bus = mdiobus_alloc_size(sizeof(struct mdio_fsl_priv));
277 	if (!bus)
278 		return -ENOMEM;
279 
280 	bus->name = "Freescale XGMAC MDIO Bus";
281 	bus->read = xgmac_mdio_read;
282 	bus->write = xgmac_mdio_write;
283 	bus->parent = &pdev->dev;
284 	bus->probe_capabilities = MDIOBUS_C22_C45;
285 	snprintf(bus->id, MII_BUS_ID_SIZE, "%pa", &res->start);
286 
287 	/* Set the PHY base address */
288 	priv = bus->priv;
289 	priv->mdio_base = ioremap(res->start, resource_size(res));
290 	if (!priv->mdio_base) {
291 		ret = -ENOMEM;
292 		goto err_ioremap;
293 	}
294 
295 	/* For both ACPI and DT cases, endianness of MDIO controller
296 	 * needs to be specified using "little-endian" property.
297 	 */
298 	priv->is_little_endian = device_property_read_bool(&pdev->dev,
299 							   "little-endian");
300 
301 	priv->has_a009885 = device_property_read_bool(&pdev->dev,
302 						      "fsl,erratum-a009885");
303 	priv->has_a011043 = device_property_read_bool(&pdev->dev,
304 						      "fsl,erratum-a011043");
305 
306 	fwnode = pdev->dev.fwnode;
307 	if (is_of_node(fwnode))
308 		ret = of_mdiobus_register(bus, to_of_node(fwnode));
309 	else if (is_acpi_node(fwnode))
310 		ret = acpi_mdiobus_register(bus, fwnode);
311 	else
312 		ret = -EINVAL;
313 	if (ret) {
314 		dev_err(&pdev->dev, "cannot register MDIO bus\n");
315 		goto err_registration;
316 	}
317 
318 	platform_set_drvdata(pdev, bus);
319 
320 	return 0;
321 
322 err_registration:
323 	iounmap(priv->mdio_base);
324 
325 err_ioremap:
326 	mdiobus_free(bus);
327 
328 	return ret;
329 }
330 
331 static int xgmac_mdio_remove(struct platform_device *pdev)
332 {
333 	struct mii_bus *bus = platform_get_drvdata(pdev);
334 	struct mdio_fsl_priv *priv = bus->priv;
335 
336 	mdiobus_unregister(bus);
337 	iounmap(priv->mdio_base);
338 	mdiobus_free(bus);
339 
340 	return 0;
341 }
342 
343 static const struct of_device_id xgmac_mdio_match[] = {
344 	{
345 		.compatible = "fsl,fman-xmdio",
346 	},
347 	{
348 		.compatible = "fsl,fman-memac-mdio",
349 	},
350 	{},
351 };
352 MODULE_DEVICE_TABLE(of, xgmac_mdio_match);
353 
354 static const struct acpi_device_id xgmac_acpi_match[] = {
355 	{ "NXP0006" },
356 	{ }
357 };
358 MODULE_DEVICE_TABLE(acpi, xgmac_acpi_match);
359 
360 static struct platform_driver xgmac_mdio_driver = {
361 	.driver = {
362 		.name = "fsl-fman_xmdio",
363 		.of_match_table = xgmac_mdio_match,
364 		.acpi_match_table = xgmac_acpi_match,
365 	},
366 	.probe = xgmac_mdio_probe,
367 	.remove = xgmac_mdio_remove,
368 };
369 
370 module_platform_driver(xgmac_mdio_driver);
371 
372 MODULE_DESCRIPTION("Freescale QorIQ 10G MDIO Controller");
373 MODULE_LICENSE("GPL v2");
374