xref: /linux/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c (revision 8a5f956a9fb7d74fff681145082acfad5afa6bb8)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*******************************************************************************
3   STMMAC Ethernet Driver -- MDIO bus implementation
4   Provides Bus interface for MII registers
5 
6   Copyright (C) 2007-2009  STMicroelectronics Ltd
7 
8 
9   Author: Carl Shaw <carl.shaw@st.com>
10   Maintainer: Giuseppe Cavallaro <peppe.cavallaro@st.com>
11 *******************************************************************************/
12 
13 #include <linux/gpio/consumer.h>
14 #include <linux/io.h>
15 #include <linux/iopoll.h>
16 #include <linux/mii.h>
17 #include <linux/of_mdio.h>
18 #include <linux/pm_runtime.h>
19 #include <linux/phy.h>
20 #include <linux/property.h>
21 #include <linux/slab.h>
22 
23 #include "dwxgmac2.h"
24 #include "stmmac.h"
25 
26 #define MII_ADDR_GBUSY			BIT(0)
27 #define MII_ADDR_GWRITE			BIT(1)
28 #define MII_DATA_GD_MASK		GENMASK(15, 0)
29 
30 /* GMAC4 defines */
31 #define MII_GMAC4_GOC_SHIFT		2
32 #define MII_GMAC4_REG_ADDR_SHIFT	16
33 #define MII_GMAC4_WRITE			(1 << MII_GMAC4_GOC_SHIFT)
34 #define MII_GMAC4_READ			(3 << MII_GMAC4_GOC_SHIFT)
35 #define MII_GMAC4_C45E			BIT(1)
36 
37 /* XGMAC defines */
38 #define MII_XGMAC_SADDR			BIT(18)
39 #define MII_XGMAC_CMD_SHIFT		16
40 #define MII_XGMAC_WRITE			(1 << MII_XGMAC_CMD_SHIFT)
41 #define MII_XGMAC_READ			(3 << MII_XGMAC_CMD_SHIFT)
42 #define MII_XGMAC_BUSY			BIT(22)
43 #define MII_XGMAC_MAX_C22ADDR		3
44 #define MII_XGMAC_C22P_MASK		GENMASK(MII_XGMAC_MAX_C22ADDR, 0)
45 #define MII_XGMAC_PA_SHIFT		16
46 #define MII_XGMAC_DA_SHIFT		21
47 
48 static int stmmac_mdio_wait(void __iomem *reg, u32 mask)
49 {
50 	u32 v;
51 
52 	if (readl_poll_timeout(reg, v, !(v & mask), 100, 10000))
53 		return -EBUSY;
54 
55 	return 0;
56 }
57 
58 static void stmmac_xgmac2_c45_format(struct stmmac_priv *priv, int phyaddr,
59 				     int devad, int phyreg, u32 *hw_addr)
60 {
61 	u32 tmp;
62 
63 	/* Set port as Clause 45 */
64 	tmp = readl(priv->ioaddr + XGMAC_MDIO_C22P);
65 	tmp &= ~BIT(phyaddr);
66 	writel(tmp, priv->ioaddr + XGMAC_MDIO_C22P);
67 
68 	*hw_addr = (phyaddr << MII_XGMAC_PA_SHIFT) | (phyreg & 0xffff);
69 	*hw_addr |= devad << MII_XGMAC_DA_SHIFT;
70 }
71 
72 static void stmmac_xgmac2_c22_format(struct stmmac_priv *priv, int phyaddr,
73 				     int phyreg, u32 *hw_addr)
74 {
75 	u32 tmp = 0;
76 
77 	if (priv->synopsys_id < DWXGMAC_CORE_2_20) {
78 		/* Until ver 2.20 XGMAC does not support C22 addr >= 4. Those
79 		 * bits above bit 3 of XGMAC_MDIO_C22P register are reserved.
80 		 */
81 		tmp = readl(priv->ioaddr + XGMAC_MDIO_C22P);
82 		tmp &= ~MII_XGMAC_C22P_MASK;
83 	}
84 	/* Set port as Clause 22 */
85 	tmp |= BIT(phyaddr);
86 	writel(tmp, priv->ioaddr + XGMAC_MDIO_C22P);
87 
88 	*hw_addr = (phyaddr << MII_XGMAC_PA_SHIFT) | (phyreg & 0x1f);
89 }
90 
91 static int stmmac_xgmac2_mdio_read(struct stmmac_priv *priv, u32 addr,
92 				   u32 value)
93 {
94 	unsigned int mii_address = priv->hw->mii.addr;
95 	unsigned int mii_data = priv->hw->mii.data;
96 	int ret;
97 
98 	ret = pm_runtime_resume_and_get(priv->device);
99 	if (ret < 0)
100 		return ret;
101 
102 	/* Wait until any existing MII operation is complete */
103 	ret = stmmac_mdio_wait(priv->ioaddr + mii_data, MII_XGMAC_BUSY);
104 	if (ret)
105 		goto err_disable_clks;
106 
107 	value |= priv->gmii_address_bus_config | MII_XGMAC_READ;
108 
109 	/* Wait until any existing MII operation is complete */
110 	ret = stmmac_mdio_wait(priv->ioaddr + mii_data, MII_XGMAC_BUSY);
111 	if (ret)
112 		goto err_disable_clks;
113 
114 	/* Set the MII address register to read */
115 	writel(addr, priv->ioaddr + mii_address);
116 	writel(value, priv->ioaddr + mii_data);
117 
118 	/* Wait until any existing MII operation is complete */
119 	ret = stmmac_mdio_wait(priv->ioaddr + mii_data, MII_XGMAC_BUSY);
120 	if (ret)
121 		goto err_disable_clks;
122 
123 	/* Read the data from the MII data register */
124 	ret = (int)readl(priv->ioaddr + mii_data) & GENMASK(15, 0);
125 
126 err_disable_clks:
127 	pm_runtime_put(priv->device);
128 
129 	return ret;
130 }
131 
132 static int stmmac_xgmac2_mdio_read_c22(struct mii_bus *bus, int phyaddr,
133 				       int phyreg)
134 {
135 	struct stmmac_priv *priv = netdev_priv(bus->priv);
136 	u32 addr;
137 
138 	/* Until ver 2.20 XGMAC does not support C22 addr >= 4 */
139 	if (priv->synopsys_id < DWXGMAC_CORE_2_20 &&
140 	    phyaddr > MII_XGMAC_MAX_C22ADDR)
141 		return -ENODEV;
142 
143 	stmmac_xgmac2_c22_format(priv, phyaddr, phyreg, &addr);
144 
145 	return stmmac_xgmac2_mdio_read(priv, addr, MII_XGMAC_BUSY);
146 }
147 
148 static int stmmac_xgmac2_mdio_read_c45(struct mii_bus *bus, int phyaddr,
149 				       int devad, int phyreg)
150 {
151 	struct stmmac_priv *priv = netdev_priv(bus->priv);
152 	u32 addr;
153 
154 	stmmac_xgmac2_c45_format(priv, phyaddr, devad, phyreg, &addr);
155 
156 	return stmmac_xgmac2_mdio_read(priv, addr, MII_XGMAC_BUSY);
157 }
158 
159 static int stmmac_xgmac2_mdio_write(struct stmmac_priv *priv, u32 addr,
160 				    u32 value, u16 phydata)
161 {
162 	unsigned int mii_address = priv->hw->mii.addr;
163 	unsigned int mii_data = priv->hw->mii.data;
164 	int ret;
165 
166 	ret = pm_runtime_resume_and_get(priv->device);
167 	if (ret < 0)
168 		return ret;
169 
170 	/* Wait until any existing MII operation is complete */
171 	ret = stmmac_mdio_wait(priv->ioaddr + mii_data, MII_XGMAC_BUSY);
172 	if (ret)
173 		goto err_disable_clks;
174 
175 	value |= priv->gmii_address_bus_config | phydata | MII_XGMAC_WRITE;
176 
177 	/* Wait until any existing MII operation is complete */
178 	ret = stmmac_mdio_wait(priv->ioaddr + mii_data, MII_XGMAC_BUSY);
179 	if (ret)
180 		goto err_disable_clks;
181 
182 	/* Set the MII address register to write */
183 	writel(addr, priv->ioaddr + mii_address);
184 	writel(value, priv->ioaddr + mii_data);
185 
186 	/* Wait until any existing MII operation is complete */
187 	ret = stmmac_mdio_wait(priv->ioaddr + mii_data, MII_XGMAC_BUSY);
188 
189 err_disable_clks:
190 	pm_runtime_put(priv->device);
191 
192 	return ret;
193 }
194 
195 static int stmmac_xgmac2_mdio_write_c22(struct mii_bus *bus, int phyaddr,
196 					int phyreg, u16 phydata)
197 {
198 	struct stmmac_priv *priv = netdev_priv(bus->priv);
199 	u32 addr;
200 
201 	/* Until ver 2.20 XGMAC does not support C22 addr >= 4 */
202 	if (priv->synopsys_id < DWXGMAC_CORE_2_20 &&
203 	    phyaddr > MII_XGMAC_MAX_C22ADDR)
204 		return -ENODEV;
205 
206 	stmmac_xgmac2_c22_format(priv, phyaddr, phyreg, &addr);
207 
208 	return stmmac_xgmac2_mdio_write(priv, addr,
209 					MII_XGMAC_BUSY | MII_XGMAC_SADDR, phydata);
210 }
211 
212 static int stmmac_xgmac2_mdio_write_c45(struct mii_bus *bus, int phyaddr,
213 					int devad, int phyreg, u16 phydata)
214 {
215 	struct stmmac_priv *priv = netdev_priv(bus->priv);
216 	u32 addr;
217 
218 	stmmac_xgmac2_c45_format(priv, phyaddr, devad, phyreg, &addr);
219 
220 	return stmmac_xgmac2_mdio_write(priv, addr, MII_XGMAC_BUSY,
221 					phydata);
222 }
223 
224 /**
225  * stmmac_mdio_format_addr() - format the address register
226  * @priv: struct stmmac_priv pointer
227  * @pa: 5-bit MDIO package address
228  * @gr: 5-bit MDIO register address (C22) or MDIO device address (C45)
229  *
230  * Return: formatted address register
231  */
232 static u32 stmmac_mdio_format_addr(struct stmmac_priv *priv,
233 				   unsigned int pa, unsigned int gr)
234 {
235 	const struct mii_regs *mii_regs = &priv->hw->mii;
236 
237 	return ((pa << mii_regs->addr_shift) & mii_regs->addr_mask) |
238 	       ((gr << mii_regs->reg_shift) & mii_regs->reg_mask) |
239 	       priv->gmii_address_bus_config |
240 	       MII_ADDR_GBUSY;
241 }
242 
243 static int stmmac_mdio_access(struct stmmac_priv *priv, unsigned int pa,
244 			      unsigned int gr, u32 cmd, u32 data, bool read)
245 {
246 	void __iomem *mii_address = priv->ioaddr + priv->hw->mii.addr;
247 	void __iomem *mii_data = priv->ioaddr + priv->hw->mii.data;
248 	u32 addr;
249 	int ret;
250 
251 	ret = pm_runtime_resume_and_get(priv->device);
252 	if (ret < 0)
253 		return ret;
254 
255 	ret = stmmac_mdio_wait(mii_address, MII_ADDR_GBUSY);
256 	if (ret)
257 		goto out;
258 
259 	addr = stmmac_mdio_format_addr(priv, pa, gr) | cmd;
260 
261 	writel(data, mii_data);
262 	writel(addr, mii_address);
263 
264 	ret = stmmac_mdio_wait(mii_address, MII_ADDR_GBUSY);
265 	if (ret)
266 		goto out;
267 
268 	/* Read the data from the MII data register if in read mode */
269 	ret = read ? readl(mii_data) & MII_DATA_GD_MASK : 0;
270 
271 out:
272 	pm_runtime_put(priv->device);
273 
274 	return ret;
275 }
276 
277 static int stmmac_mdio_read(struct stmmac_priv *priv, unsigned int pa,
278 			    unsigned int gr, u32 cmd, int data)
279 {
280 	return stmmac_mdio_access(priv, pa, gr, cmd, data, true);
281 }
282 
283 static int stmmac_mdio_write(struct stmmac_priv *priv, unsigned int pa,
284 			     unsigned int gr, u32 cmd, int data)
285 {
286 	return stmmac_mdio_access(priv, pa, gr, cmd, data, false);
287 }
288 
289 /**
290  * stmmac_mdio_read_c22
291  * @bus: points to the mii_bus structure
292  * @phyaddr: MII addr
293  * @phyreg: MII reg
294  * Description: it reads data from the MII register from within the phy device.
295  * For the 7111 GMAC, we must set the bit 0 in the MII address register while
296  * accessing the PHY registers.
297  * Fortunately, it seems this has no drawback for the 7109 MAC.
298  */
299 static int stmmac_mdio_read_c22(struct mii_bus *bus, int phyaddr, int phyreg)
300 {
301 	struct stmmac_priv *priv = netdev_priv(bus->priv);
302 	u32 cmd;
303 
304 	if (priv->plat->has_gmac4)
305 		cmd = MII_GMAC4_READ;
306 	else
307 		cmd = 0;
308 
309 	return stmmac_mdio_read(priv, phyaddr, phyreg, cmd, 0);
310 }
311 
312 /**
313  * stmmac_mdio_read_c45
314  * @bus: points to the mii_bus structure
315  * @phyaddr: MII addr
316  * @devad: device address to read
317  * @phyreg: MII reg
318  * Description: it reads data from the MII register from within the phy device.
319  * For the 7111 GMAC, we must set the bit 0 in the MII address register while
320  * accessing the PHY registers.
321  * Fortunately, it seems this has no drawback for the 7109 MAC.
322  */
323 static int stmmac_mdio_read_c45(struct mii_bus *bus, int phyaddr, int devad,
324 				int phyreg)
325 {
326 	struct stmmac_priv *priv = netdev_priv(bus->priv);
327 	int data = phyreg << MII_GMAC4_REG_ADDR_SHIFT;
328 	u32 cmd = MII_GMAC4_READ | MII_GMAC4_C45E;
329 
330 	return stmmac_mdio_read(priv, phyaddr, devad, cmd, data);
331 }
332 
333 /**
334  * stmmac_mdio_write_c22
335  * @bus: points to the mii_bus structure
336  * @phyaddr: MII addr
337  * @phyreg: MII reg
338  * @phydata: phy data
339  * Description: it writes the data into the MII register from within the device.
340  */
341 static int stmmac_mdio_write_c22(struct mii_bus *bus, int phyaddr, int phyreg,
342 				 u16 phydata)
343 {
344 	struct stmmac_priv *priv = netdev_priv(bus->priv);
345 	u32 cmd;
346 
347 	if (priv->plat->has_gmac4)
348 		cmd = MII_GMAC4_WRITE;
349 	else
350 		cmd = MII_ADDR_GWRITE;
351 
352 	return stmmac_mdio_write(priv, phyaddr, phyreg, cmd, phydata);
353 }
354 
355 /**
356  * stmmac_mdio_write_c45
357  * @bus: points to the mii_bus structure
358  * @phyaddr: MII addr
359  * @phyreg: MII reg
360  * @devad: device address to read
361  * @phydata: phy data
362  * Description: it writes the data into the MII register from within the device.
363  */
364 static int stmmac_mdio_write_c45(struct mii_bus *bus, int phyaddr,
365 				 int devad, int phyreg, u16 phydata)
366 {
367 	struct stmmac_priv *priv = netdev_priv(bus->priv);
368 	u32 cmd = MII_GMAC4_WRITE | MII_GMAC4_C45E;
369 	int data = phydata;
370 
371 	data |= phyreg << MII_GMAC4_REG_ADDR_SHIFT;
372 
373 	return stmmac_mdio_write(priv, phyaddr, devad, cmd, data);
374 }
375 
376 /**
377  * stmmac_mdio_reset
378  * @bus: points to the mii_bus structure
379  * Description: reset the MII bus
380  */
381 int stmmac_mdio_reset(struct mii_bus *bus)
382 {
383 #if IS_ENABLED(CONFIG_STMMAC_PLATFORM)
384 	struct stmmac_priv *priv = netdev_priv(bus->priv);
385 	unsigned int mii_address = priv->hw->mii.addr;
386 
387 #ifdef CONFIG_OF
388 	if (priv->device->of_node) {
389 		struct gpio_desc *reset_gpio;
390 		u32 delays[3] = { 0, 0, 0 };
391 
392 		reset_gpio = devm_gpiod_get_optional(priv->device,
393 						     "snps,reset",
394 						     GPIOD_OUT_LOW);
395 		if (IS_ERR(reset_gpio))
396 			return PTR_ERR(reset_gpio);
397 
398 		device_property_read_u32_array(priv->device,
399 					       "snps,reset-delays-us",
400 					       delays, ARRAY_SIZE(delays));
401 
402 		if (delays[0])
403 			msleep(DIV_ROUND_UP(delays[0], 1000));
404 
405 		gpiod_set_value_cansleep(reset_gpio, 1);
406 		if (delays[1])
407 			msleep(DIV_ROUND_UP(delays[1], 1000));
408 
409 		gpiod_set_value_cansleep(reset_gpio, 0);
410 		if (delays[2])
411 			msleep(DIV_ROUND_UP(delays[2], 1000));
412 	}
413 #endif
414 
415 	/* This is a workaround for problems with the STE101P PHY.
416 	 * It doesn't complete its reset until at least one clock cycle
417 	 * on MDC, so perform a dummy mdio read. To be updated for GMAC4
418 	 * if needed.
419 	 */
420 	if (!priv->plat->has_gmac4)
421 		writel(0, priv->ioaddr + mii_address);
422 #endif
423 	return 0;
424 }
425 
426 int stmmac_pcs_setup(struct net_device *ndev)
427 {
428 	struct stmmac_priv *priv = netdev_priv(ndev);
429 	struct fwnode_handle *devnode, *pcsnode;
430 	struct dw_xpcs *xpcs = NULL;
431 	int addr, ret;
432 
433 	devnode = priv->plat->port_node;
434 
435 	if (priv->plat->pcs_init) {
436 		ret = priv->plat->pcs_init(priv);
437 	} else if (fwnode_property_present(devnode, "pcs-handle")) {
438 		pcsnode = fwnode_find_reference(devnode, "pcs-handle", 0);
439 		xpcs = xpcs_create_fwnode(pcsnode);
440 		fwnode_handle_put(pcsnode);
441 		ret = PTR_ERR_OR_ZERO(xpcs);
442 	} else if (priv->plat->mdio_bus_data &&
443 		   priv->plat->mdio_bus_data->pcs_mask) {
444 		addr = ffs(priv->plat->mdio_bus_data->pcs_mask) - 1;
445 		xpcs = xpcs_create_mdiodev(priv->mii, addr);
446 		ret = PTR_ERR_OR_ZERO(xpcs);
447 	} else {
448 		return 0;
449 	}
450 
451 	if (ret)
452 		return dev_err_probe(priv->device, ret, "No xPCS found\n");
453 
454 	if (xpcs)
455 		xpcs_config_eee_mult_fact(xpcs, priv->plat->mult_fact_100ns);
456 
457 	priv->hw->xpcs = xpcs;
458 
459 	return 0;
460 }
461 
462 void stmmac_pcs_clean(struct net_device *ndev)
463 {
464 	struct stmmac_priv *priv = netdev_priv(ndev);
465 
466 	if (priv->plat->pcs_exit)
467 		priv->plat->pcs_exit(priv);
468 
469 	if (!priv->hw->xpcs)
470 		return;
471 
472 	xpcs_destroy(priv->hw->xpcs);
473 	priv->hw->xpcs = NULL;
474 }
475 
476 /**
477  * stmmac_clk_csr_set - dynamically set the MDC clock
478  * @priv: driver private structure
479  * Description: this is to dynamically set the MDC clock according to the csr
480  * clock input.
481  * Return: MII register CR field value
482  * Note:
483  *	If a specific clk_csr value is passed from the platform
484  *	this means that the CSR Clock Range selection cannot be
485  *	changed at run-time and it is fixed (as reported in the driver
486  *	documentation). Viceversa the driver will try to set the MDC
487  *	clock dynamically according to the actual clock input.
488  */
489 static u32 stmmac_clk_csr_set(struct stmmac_priv *priv)
490 {
491 	unsigned long clk_rate;
492 	u32 value = ~0;
493 
494 	clk_rate = clk_get_rate(priv->plat->stmmac_clk);
495 
496 	/* Platform provided default clk_csr would be assumed valid
497 	 * for all other cases except for the below mentioned ones.
498 	 * For values higher than the IEEE 802.3 specified frequency
499 	 * we can not estimate the proper divider as it is not known
500 	 * the frequency of clk_csr_i. So we do not change the default
501 	 * divider.
502 	 */
503 	if (clk_rate < CSR_F_35M)
504 		value = STMMAC_CSR_20_35M;
505 	else if (clk_rate < CSR_F_60M)
506 		value = STMMAC_CSR_35_60M;
507 	else if (clk_rate < CSR_F_100M)
508 		value = STMMAC_CSR_60_100M;
509 	else if (clk_rate < CSR_F_150M)
510 		value = STMMAC_CSR_100_150M;
511 	else if (clk_rate < CSR_F_250M)
512 		value = STMMAC_CSR_150_250M;
513 	else if (clk_rate <= CSR_F_300M)
514 		value = STMMAC_CSR_250_300M;
515 	else if (clk_rate < CSR_F_500M)
516 		value = STMMAC_CSR_300_500M;
517 	else if (clk_rate < CSR_F_800M)
518 		value = STMMAC_CSR_500_800M;
519 
520 	if (priv->plat->flags & STMMAC_FLAG_HAS_SUN8I) {
521 		if (clk_rate > 160000000)
522 			value = 0x03;
523 		else if (clk_rate > 80000000)
524 			value = 0x02;
525 		else if (clk_rate > 40000000)
526 			value = 0x01;
527 		else
528 			value = 0;
529 	}
530 
531 	if (priv->plat->has_xgmac) {
532 		if (clk_rate > 400000000)
533 			value = 0x5;
534 		else if (clk_rate > 350000000)
535 			value = 0x4;
536 		else if (clk_rate > 300000000)
537 			value = 0x3;
538 		else if (clk_rate > 250000000)
539 			value = 0x2;
540 		else if (clk_rate > 150000000)
541 			value = 0x1;
542 		else
543 			value = 0x0;
544 	}
545 
546 	return value;
547 }
548 
549 static void stmmac_mdio_bus_config(struct stmmac_priv *priv)
550 {
551 	u32 value;
552 
553 	/* If a specific clk_csr value is passed from the platform, this means
554 	 * that the CSR Clock Range value should not be computed from the CSR
555 	 * clock.
556 	 */
557 	if (priv->plat->clk_csr >= 0)
558 		value = priv->plat->clk_csr;
559 	else
560 		value = stmmac_clk_csr_set(priv);
561 
562 	value <<= priv->hw->mii.clk_csr_shift;
563 
564 	if (value & ~priv->hw->mii.clk_csr_mask)
565 		dev_warn(priv->device,
566 			 "clk_csr value out of range (0x%08x exceeds mask 0x%08x), truncating\n",
567 			 value, priv->hw->mii.clk_csr_mask);
568 
569 	priv->gmii_address_bus_config = value & priv->hw->mii.clk_csr_mask;
570 }
571 
572 /**
573  * stmmac_mdio_register
574  * @ndev: net device structure
575  * Description: it registers the MII bus
576  */
577 int stmmac_mdio_register(struct net_device *ndev)
578 {
579 	int err = 0;
580 	struct mii_bus *new_bus;
581 	struct stmmac_priv *priv = netdev_priv(ndev);
582 	struct stmmac_mdio_bus_data *mdio_bus_data = priv->plat->mdio_bus_data;
583 	struct device_node *mdio_node = priv->plat->mdio_node;
584 	struct device *dev = ndev->dev.parent;
585 	struct fwnode_handle *fixed_node;
586 	struct fwnode_handle *fwnode;
587 	int addr, found, max_addr;
588 
589 	if (!mdio_bus_data)
590 		return 0;
591 
592 	stmmac_mdio_bus_config(priv);
593 
594 	new_bus = mdiobus_alloc();
595 	if (!new_bus)
596 		return -ENOMEM;
597 
598 	if (mdio_bus_data->irqs)
599 		memcpy(new_bus->irq, mdio_bus_data->irqs, sizeof(new_bus->irq));
600 
601 	new_bus->name = "stmmac";
602 
603 	if (priv->plat->has_xgmac) {
604 		new_bus->read = &stmmac_xgmac2_mdio_read_c22;
605 		new_bus->write = &stmmac_xgmac2_mdio_write_c22;
606 		new_bus->read_c45 = &stmmac_xgmac2_mdio_read_c45;
607 		new_bus->write_c45 = &stmmac_xgmac2_mdio_write_c45;
608 
609 		if (priv->synopsys_id < DWXGMAC_CORE_2_20) {
610 			/* Right now only C22 phys are supported */
611 			max_addr = MII_XGMAC_MAX_C22ADDR + 1;
612 
613 			/* Check if DT specified an unsupported phy addr */
614 			if (priv->plat->phy_addr > MII_XGMAC_MAX_C22ADDR)
615 				dev_err(dev, "Unsupported phy_addr (max=%d)\n",
616 					MII_XGMAC_MAX_C22ADDR);
617 		} else {
618 			/* XGMAC version 2.20 onwards support 32 phy addr */
619 			max_addr = PHY_MAX_ADDR;
620 		}
621 	} else {
622 		new_bus->read = &stmmac_mdio_read_c22;
623 		new_bus->write = &stmmac_mdio_write_c22;
624 		if (priv->plat->has_gmac4) {
625 			new_bus->read_c45 = &stmmac_mdio_read_c45;
626 			new_bus->write_c45 = &stmmac_mdio_write_c45;
627 		}
628 
629 		max_addr = PHY_MAX_ADDR;
630 	}
631 
632 	if (mdio_bus_data->needs_reset)
633 		new_bus->reset = &stmmac_mdio_reset;
634 
635 	snprintf(new_bus->id, MII_BUS_ID_SIZE, "%s-%x",
636 		 new_bus->name, priv->plat->bus_id);
637 	new_bus->priv = ndev;
638 	new_bus->phy_mask = mdio_bus_data->phy_mask | mdio_bus_data->pcs_mask;
639 	new_bus->parent = priv->device;
640 
641 	err = of_mdiobus_register(new_bus, mdio_node);
642 	if (err == -ENODEV) {
643 		err = 0;
644 		dev_info(dev, "MDIO bus is disabled\n");
645 		goto bus_register_fail;
646 	} else if (err) {
647 		dev_err_probe(dev, err, "Cannot register the MDIO bus\n");
648 		goto bus_register_fail;
649 	}
650 
651 	/* Looks like we need a dummy read for XGMAC only and C45 PHYs */
652 	if (priv->plat->has_xgmac)
653 		stmmac_xgmac2_mdio_read_c45(new_bus, 0, 0, 0);
654 
655 	/* If fixed-link is set, skip PHY scanning */
656 	fwnode = priv->plat->port_node;
657 	if (!fwnode)
658 		fwnode = dev_fwnode(priv->device);
659 
660 	if (fwnode) {
661 		fixed_node = fwnode_get_named_child_node(fwnode, "fixed-link");
662 		if (fixed_node) {
663 			fwnode_handle_put(fixed_node);
664 			goto bus_register_done;
665 		}
666 	}
667 
668 	if (priv->plat->phy_node || mdio_node)
669 		goto bus_register_done;
670 
671 	found = 0;
672 	for (addr = 0; addr < max_addr; addr++) {
673 		struct phy_device *phydev = mdiobus_get_phy(new_bus, addr);
674 
675 		if (!phydev)
676 			continue;
677 
678 		/*
679 		 * If an IRQ was provided to be assigned after
680 		 * the bus probe, do it here.
681 		 */
682 		if (!mdio_bus_data->irqs &&
683 		    (mdio_bus_data->probed_phy_irq > 0)) {
684 			new_bus->irq[addr] = mdio_bus_data->probed_phy_irq;
685 			phydev->irq = mdio_bus_data->probed_phy_irq;
686 		}
687 
688 		/*
689 		 * If we're going to bind the MAC to this PHY bus,
690 		 * and no PHY number was provided to the MAC,
691 		 * use the one probed here.
692 		 */
693 		if (priv->plat->phy_addr == -1)
694 			priv->plat->phy_addr = addr;
695 
696 		phy_attached_info(phydev);
697 		found = 1;
698 	}
699 
700 	if (!found && !mdio_node) {
701 		dev_warn(dev, "No PHY found\n");
702 		err = -ENODEV;
703 		goto no_phy_found;
704 	}
705 
706 bus_register_done:
707 	priv->mii = new_bus;
708 
709 	return 0;
710 
711 no_phy_found:
712 	mdiobus_unregister(new_bus);
713 bus_register_fail:
714 	mdiobus_free(new_bus);
715 	return err;
716 }
717 
718 /**
719  * stmmac_mdio_unregister
720  * @ndev: net device structure
721  * Description: it unregisters the MII bus
722  */
723 int stmmac_mdio_unregister(struct net_device *ndev)
724 {
725 	struct stmmac_priv *priv = netdev_priv(ndev);
726 
727 	if (!priv->mii)
728 		return 0;
729 
730 	mdiobus_unregister(priv->mii);
731 	priv->mii->priv = NULL;
732 	mdiobus_free(priv->mii);
733 	priv->mii = NULL;
734 
735 	return 0;
736 }
737