xref: /linux/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
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_BUSY 0x00000001
27 #define MII_WRITE 0x00000002
28 #define MII_DATA_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 void stmmac_xgmac2_c45_format(struct stmmac_priv *priv, int phyaddr,
49 				     int devad, int phyreg, u32 *hw_addr)
50 {
51 	u32 tmp;
52 
53 	/* Set port as Clause 45 */
54 	tmp = readl(priv->ioaddr + XGMAC_MDIO_C22P);
55 	tmp &= ~BIT(phyaddr);
56 	writel(tmp, priv->ioaddr + XGMAC_MDIO_C22P);
57 
58 	*hw_addr = (phyaddr << MII_XGMAC_PA_SHIFT) | (phyreg & 0xffff);
59 	*hw_addr |= devad << MII_XGMAC_DA_SHIFT;
60 }
61 
62 static void stmmac_xgmac2_c22_format(struct stmmac_priv *priv, int phyaddr,
63 				     int phyreg, u32 *hw_addr)
64 {
65 	u32 tmp = 0;
66 
67 	if (priv->synopsys_id < DWXGMAC_CORE_2_20) {
68 		/* Until ver 2.20 XGMAC does not support C22 addr >= 4. Those
69 		 * bits above bit 3 of XGMAC_MDIO_C22P register are reserved.
70 		 */
71 		tmp = readl(priv->ioaddr + XGMAC_MDIO_C22P);
72 		tmp &= ~MII_XGMAC_C22P_MASK;
73 	}
74 	/* Set port as Clause 22 */
75 	tmp |= BIT(phyaddr);
76 	writel(tmp, priv->ioaddr + XGMAC_MDIO_C22P);
77 
78 	*hw_addr = (phyaddr << MII_XGMAC_PA_SHIFT) | (phyreg & 0x1f);
79 }
80 
81 static int stmmac_xgmac2_mdio_read(struct stmmac_priv *priv, u32 addr,
82 				   u32 value)
83 {
84 	unsigned int mii_address = priv->hw->mii.addr;
85 	unsigned int mii_data = priv->hw->mii.data;
86 	u32 tmp;
87 	int ret;
88 
89 	ret = pm_runtime_resume_and_get(priv->device);
90 	if (ret < 0)
91 		return ret;
92 
93 	/* Wait until any existing MII operation is complete */
94 	if (readl_poll_timeout(priv->ioaddr + mii_data, tmp,
95 			       !(tmp & MII_XGMAC_BUSY), 100, 10000)) {
96 		ret = -EBUSY;
97 		goto err_disable_clks;
98 	}
99 
100 	value |= (priv->clk_csr << priv->hw->mii.clk_csr_shift)
101 		& priv->hw->mii.clk_csr_mask;
102 	value |= MII_XGMAC_READ;
103 
104 	/* Wait until any existing MII operation is complete */
105 	if (readl_poll_timeout(priv->ioaddr + mii_data, tmp,
106 			       !(tmp & MII_XGMAC_BUSY), 100, 10000)) {
107 		ret = -EBUSY;
108 		goto err_disable_clks;
109 	}
110 
111 	/* Set the MII address register to read */
112 	writel(addr, priv->ioaddr + mii_address);
113 	writel(value, priv->ioaddr + mii_data);
114 
115 	/* Wait until any existing MII operation is complete */
116 	if (readl_poll_timeout(priv->ioaddr + mii_data, tmp,
117 			       !(tmp & MII_XGMAC_BUSY), 100, 10000)) {
118 		ret = -EBUSY;
119 		goto err_disable_clks;
120 	}
121 
122 	/* Read the data from the MII data register */
123 	ret = (int)readl(priv->ioaddr + mii_data) & GENMASK(15, 0);
124 
125 err_disable_clks:
126 	pm_runtime_put(priv->device);
127 
128 	return ret;
129 }
130 
131 static int stmmac_xgmac2_mdio_read_c22(struct mii_bus *bus, int phyaddr,
132 				       int phyreg)
133 {
134 	struct net_device *ndev = bus->priv;
135 	struct stmmac_priv *priv;
136 	u32 addr;
137 
138 	priv = netdev_priv(ndev);
139 
140 	/* Until ver 2.20 XGMAC does not support C22 addr >= 4 */
141 	if (priv->synopsys_id < DWXGMAC_CORE_2_20 &&
142 	    phyaddr > MII_XGMAC_MAX_C22ADDR)
143 		return -ENODEV;
144 
145 	stmmac_xgmac2_c22_format(priv, phyaddr, phyreg, &addr);
146 
147 	return stmmac_xgmac2_mdio_read(priv, addr, MII_XGMAC_BUSY);
148 }
149 
150 static int stmmac_xgmac2_mdio_read_c45(struct mii_bus *bus, int phyaddr,
151 				       int devad, int phyreg)
152 {
153 	struct net_device *ndev = bus->priv;
154 	struct stmmac_priv *priv;
155 	u32 addr;
156 
157 	priv = netdev_priv(ndev);
158 
159 	stmmac_xgmac2_c45_format(priv, phyaddr, devad, phyreg, &addr);
160 
161 	return stmmac_xgmac2_mdio_read(priv, addr, MII_XGMAC_BUSY);
162 }
163 
164 static int stmmac_xgmac2_mdio_write(struct stmmac_priv *priv, u32 addr,
165 				    u32 value, u16 phydata)
166 {
167 	unsigned int mii_address = priv->hw->mii.addr;
168 	unsigned int mii_data = priv->hw->mii.data;
169 	u32 tmp;
170 	int ret;
171 
172 	ret = pm_runtime_resume_and_get(priv->device);
173 	if (ret < 0)
174 		return ret;
175 
176 	/* Wait until any existing MII operation is complete */
177 	if (readl_poll_timeout(priv->ioaddr + mii_data, tmp,
178 			       !(tmp & MII_XGMAC_BUSY), 100, 10000)) {
179 		ret = -EBUSY;
180 		goto err_disable_clks;
181 	}
182 
183 	value |= (priv->clk_csr << priv->hw->mii.clk_csr_shift)
184 		& priv->hw->mii.clk_csr_mask;
185 	value |= phydata;
186 	value |= MII_XGMAC_WRITE;
187 
188 	/* Wait until any existing MII operation is complete */
189 	if (readl_poll_timeout(priv->ioaddr + mii_data, tmp,
190 			       !(tmp & MII_XGMAC_BUSY), 100, 10000)) {
191 		ret = -EBUSY;
192 		goto err_disable_clks;
193 	}
194 
195 	/* Set the MII address register to write */
196 	writel(addr, priv->ioaddr + mii_address);
197 	writel(value, priv->ioaddr + mii_data);
198 
199 	/* Wait until any existing MII operation is complete */
200 	ret = readl_poll_timeout(priv->ioaddr + mii_data, tmp,
201 				 !(tmp & MII_XGMAC_BUSY), 100, 10000);
202 
203 err_disable_clks:
204 	pm_runtime_put(priv->device);
205 
206 	return ret;
207 }
208 
209 static int stmmac_xgmac2_mdio_write_c22(struct mii_bus *bus, int phyaddr,
210 					int phyreg, u16 phydata)
211 {
212 	struct net_device *ndev = bus->priv;
213 	struct stmmac_priv *priv;
214 	u32 addr;
215 
216 	priv = netdev_priv(ndev);
217 
218 	/* Until ver 2.20 XGMAC does not support C22 addr >= 4 */
219 	if (priv->synopsys_id < DWXGMAC_CORE_2_20 &&
220 	    phyaddr > MII_XGMAC_MAX_C22ADDR)
221 		return -ENODEV;
222 
223 	stmmac_xgmac2_c22_format(priv, phyaddr, phyreg, &addr);
224 
225 	return stmmac_xgmac2_mdio_write(priv, addr,
226 					MII_XGMAC_BUSY | MII_XGMAC_SADDR, phydata);
227 }
228 
229 static int stmmac_xgmac2_mdio_write_c45(struct mii_bus *bus, int phyaddr,
230 					int devad, int phyreg, u16 phydata)
231 {
232 	struct net_device *ndev = bus->priv;
233 	struct stmmac_priv *priv;
234 	u32 addr;
235 
236 	priv = netdev_priv(ndev);
237 
238 	stmmac_xgmac2_c45_format(priv, phyaddr, devad, phyreg, &addr);
239 
240 	return stmmac_xgmac2_mdio_write(priv, addr, MII_XGMAC_BUSY,
241 					phydata);
242 }
243 
244 static int stmmac_mdio_read(struct stmmac_priv *priv, int data, u32 value)
245 {
246 	unsigned int mii_address = priv->hw->mii.addr;
247 	unsigned int mii_data = priv->hw->mii.data;
248 	u32 v;
249 
250 	if (readl_poll_timeout(priv->ioaddr + mii_address, v, !(v & MII_BUSY),
251 			       100, 10000))
252 		return -EBUSY;
253 
254 	writel(data, priv->ioaddr + mii_data);
255 	writel(value, priv->ioaddr + mii_address);
256 
257 	if (readl_poll_timeout(priv->ioaddr + mii_address, v, !(v & MII_BUSY),
258 			       100, 10000))
259 		return -EBUSY;
260 
261 	/* Read the data from the MII data register */
262 	return readl(priv->ioaddr + mii_data) & MII_DATA_MASK;
263 }
264 
265 /**
266  * stmmac_mdio_read_c22
267  * @bus: points to the mii_bus structure
268  * @phyaddr: MII addr
269  * @phyreg: MII reg
270  * Description: it reads data from the MII register from within the phy device.
271  * For the 7111 GMAC, we must set the bit 0 in the MII address register while
272  * accessing the PHY registers.
273  * Fortunately, it seems this has no drawback for the 7109 MAC.
274  */
275 static int stmmac_mdio_read_c22(struct mii_bus *bus, int phyaddr, int phyreg)
276 {
277 	struct net_device *ndev = bus->priv;
278 	struct stmmac_priv *priv = netdev_priv(ndev);
279 	u32 value = MII_BUSY;
280 	int data = 0;
281 
282 	data = pm_runtime_resume_and_get(priv->device);
283 	if (data < 0)
284 		return data;
285 
286 	value |= (phyaddr << priv->hw->mii.addr_shift)
287 		& priv->hw->mii.addr_mask;
288 	value |= (phyreg << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
289 	value |= (priv->clk_csr << priv->hw->mii.clk_csr_shift)
290 		& priv->hw->mii.clk_csr_mask;
291 	if (priv->plat->has_gmac4)
292 		value |= MII_GMAC4_READ;
293 
294 	data = stmmac_mdio_read(priv, data, value);
295 
296 	pm_runtime_put(priv->device);
297 
298 	return data;
299 }
300 
301 /**
302  * stmmac_mdio_read_c45
303  * @bus: points to the mii_bus structure
304  * @phyaddr: MII addr
305  * @devad: device address to read
306  * @phyreg: MII reg
307  * Description: it reads data from the MII register from within the phy device.
308  * For the 7111 GMAC, we must set the bit 0 in the MII address register while
309  * accessing the PHY registers.
310  * Fortunately, it seems this has no drawback for the 7109 MAC.
311  */
312 static int stmmac_mdio_read_c45(struct mii_bus *bus, int phyaddr, int devad,
313 				int phyreg)
314 {
315 	struct net_device *ndev = bus->priv;
316 	struct stmmac_priv *priv = netdev_priv(ndev);
317 	u32 value = MII_BUSY;
318 	int data = 0;
319 
320 	data = pm_runtime_get_sync(priv->device);
321 	if (data < 0) {
322 		pm_runtime_put_noidle(priv->device);
323 		return data;
324 	}
325 
326 	value |= (phyaddr << priv->hw->mii.addr_shift)
327 		& priv->hw->mii.addr_mask;
328 	value |= (phyreg << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
329 	value |= (priv->clk_csr << priv->hw->mii.clk_csr_shift)
330 		& priv->hw->mii.clk_csr_mask;
331 	value |= MII_GMAC4_READ;
332 	value |= MII_GMAC4_C45E;
333 	value &= ~priv->hw->mii.reg_mask;
334 	value |= (devad << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
335 
336 	data |= phyreg << MII_GMAC4_REG_ADDR_SHIFT;
337 
338 	data = stmmac_mdio_read(priv, data, value);
339 
340 	pm_runtime_put(priv->device);
341 
342 	return data;
343 }
344 
345 static int stmmac_mdio_write(struct stmmac_priv *priv, int data, u32 value)
346 {
347 	unsigned int mii_address = priv->hw->mii.addr;
348 	unsigned int mii_data = priv->hw->mii.data;
349 	u32 v;
350 
351 	/* Wait until any existing MII operation is complete */
352 	if (readl_poll_timeout(priv->ioaddr + mii_address, v, !(v & MII_BUSY),
353 			       100, 10000))
354 		return -EBUSY;
355 
356 	/* Set the MII address register to write */
357 	writel(data, priv->ioaddr + mii_data);
358 	writel(value, priv->ioaddr + mii_address);
359 
360 	/* Wait until any existing MII operation is complete */
361 	return readl_poll_timeout(priv->ioaddr + mii_address, v,
362 				  !(v & MII_BUSY), 100, 10000);
363 }
364 
365 /**
366  * stmmac_mdio_write_c22
367  * @bus: points to the mii_bus structure
368  * @phyaddr: MII addr
369  * @phyreg: MII reg
370  * @phydata: phy data
371  * Description: it writes the data into the MII register from within the device.
372  */
373 static int stmmac_mdio_write_c22(struct mii_bus *bus, int phyaddr, int phyreg,
374 				 u16 phydata)
375 {
376 	struct net_device *ndev = bus->priv;
377 	struct stmmac_priv *priv = netdev_priv(ndev);
378 	int ret, data = phydata;
379 	u32 value = MII_BUSY;
380 
381 	ret = pm_runtime_resume_and_get(priv->device);
382 	if (ret < 0)
383 		return ret;
384 
385 	value |= (phyaddr << priv->hw->mii.addr_shift)
386 		& priv->hw->mii.addr_mask;
387 	value |= (phyreg << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
388 
389 	value |= (priv->clk_csr << priv->hw->mii.clk_csr_shift)
390 		& priv->hw->mii.clk_csr_mask;
391 	if (priv->plat->has_gmac4)
392 		value |= MII_GMAC4_WRITE;
393 	else
394 		value |= MII_WRITE;
395 
396 	ret = stmmac_mdio_write(priv, data, value);
397 
398 	pm_runtime_put(priv->device);
399 
400 	return ret;
401 }
402 
403 /**
404  * stmmac_mdio_write_c45
405  * @bus: points to the mii_bus structure
406  * @phyaddr: MII addr
407  * @phyreg: MII reg
408  * @devad: device address to read
409  * @phydata: phy data
410  * Description: it writes the data into the MII register from within the device.
411  */
412 static int stmmac_mdio_write_c45(struct mii_bus *bus, int phyaddr,
413 				 int devad, int phyreg, u16 phydata)
414 {
415 	struct net_device *ndev = bus->priv;
416 	struct stmmac_priv *priv = netdev_priv(ndev);
417 	int ret, data = phydata;
418 	u32 value = MII_BUSY;
419 
420 	ret = pm_runtime_get_sync(priv->device);
421 	if (ret < 0) {
422 		pm_runtime_put_noidle(priv->device);
423 		return ret;
424 	}
425 
426 	value |= (phyaddr << priv->hw->mii.addr_shift)
427 		& priv->hw->mii.addr_mask;
428 	value |= (phyreg << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
429 
430 	value |= (priv->clk_csr << priv->hw->mii.clk_csr_shift)
431 		& priv->hw->mii.clk_csr_mask;
432 
433 	value |= MII_GMAC4_WRITE;
434 	value |= MII_GMAC4_C45E;
435 	value &= ~priv->hw->mii.reg_mask;
436 	value |= (devad << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
437 
438 	data |= phyreg << MII_GMAC4_REG_ADDR_SHIFT;
439 
440 	ret = stmmac_mdio_write(priv, data, value);
441 
442 	pm_runtime_put(priv->device);
443 
444 	return ret;
445 }
446 
447 /**
448  * stmmac_mdio_reset
449  * @bus: points to the mii_bus structure
450  * Description: reset the MII bus
451  */
452 int stmmac_mdio_reset(struct mii_bus *bus)
453 {
454 #if IS_ENABLED(CONFIG_STMMAC_PLATFORM)
455 	struct net_device *ndev = bus->priv;
456 	struct stmmac_priv *priv = netdev_priv(ndev);
457 	unsigned int mii_address = priv->hw->mii.addr;
458 
459 #ifdef CONFIG_OF
460 	if (priv->device->of_node) {
461 		struct gpio_desc *reset_gpio;
462 		u32 delays[3] = { 0, 0, 0 };
463 
464 		reset_gpio = devm_gpiod_get_optional(priv->device,
465 						     "snps,reset",
466 						     GPIOD_OUT_LOW);
467 		if (IS_ERR(reset_gpio))
468 			return PTR_ERR(reset_gpio);
469 
470 		device_property_read_u32_array(priv->device,
471 					       "snps,reset-delays-us",
472 					       delays, ARRAY_SIZE(delays));
473 
474 		if (delays[0])
475 			msleep(DIV_ROUND_UP(delays[0], 1000));
476 
477 		gpiod_set_value_cansleep(reset_gpio, 1);
478 		if (delays[1])
479 			msleep(DIV_ROUND_UP(delays[1], 1000));
480 
481 		gpiod_set_value_cansleep(reset_gpio, 0);
482 		if (delays[2])
483 			msleep(DIV_ROUND_UP(delays[2], 1000));
484 	}
485 #endif
486 
487 	/* This is a workaround for problems with the STE101P PHY.
488 	 * It doesn't complete its reset until at least one clock cycle
489 	 * on MDC, so perform a dummy mdio read. To be updated for GMAC4
490 	 * if needed.
491 	 */
492 	if (!priv->plat->has_gmac4)
493 		writel(0, priv->ioaddr + mii_address);
494 #endif
495 	return 0;
496 }
497 
498 int stmmac_pcs_setup(struct net_device *ndev)
499 {
500 	struct fwnode_handle *devnode, *pcsnode;
501 	struct dw_xpcs *xpcs = NULL;
502 	struct stmmac_priv *priv;
503 	int addr, mode, ret;
504 
505 	priv = netdev_priv(ndev);
506 	mode = priv->plat->phy_interface;
507 	devnode = priv->plat->port_node;
508 
509 	if (priv->plat->pcs_init) {
510 		ret = priv->plat->pcs_init(priv);
511 	} else if (fwnode_property_present(devnode, "pcs-handle")) {
512 		pcsnode = fwnode_find_reference(devnode, "pcs-handle", 0);
513 		xpcs = xpcs_create_fwnode(pcsnode, mode);
514 		fwnode_handle_put(pcsnode);
515 		ret = PTR_ERR_OR_ZERO(xpcs);
516 	} else if (priv->plat->mdio_bus_data &&
517 		   priv->plat->mdio_bus_data->pcs_mask) {
518 		addr = ffs(priv->plat->mdio_bus_data->pcs_mask) - 1;
519 		xpcs = xpcs_create_mdiodev(priv->mii, addr, mode);
520 		ret = PTR_ERR_OR_ZERO(xpcs);
521 	} else {
522 		return 0;
523 	}
524 
525 	if (ret)
526 		return dev_err_probe(priv->device, ret, "No xPCS found\n");
527 
528 	priv->hw->xpcs = xpcs;
529 
530 	return 0;
531 }
532 
533 void stmmac_pcs_clean(struct net_device *ndev)
534 {
535 	struct stmmac_priv *priv = netdev_priv(ndev);
536 
537 	if (priv->plat->pcs_exit)
538 		priv->plat->pcs_exit(priv);
539 
540 	if (!priv->hw->xpcs)
541 		return;
542 
543 	xpcs_destroy(priv->hw->xpcs);
544 	priv->hw->xpcs = NULL;
545 }
546 
547 /**
548  * stmmac_mdio_register
549  * @ndev: net device structure
550  * Description: it registers the MII bus
551  */
552 int stmmac_mdio_register(struct net_device *ndev)
553 {
554 	int err = 0;
555 	struct mii_bus *new_bus;
556 	struct stmmac_priv *priv = netdev_priv(ndev);
557 	struct stmmac_mdio_bus_data *mdio_bus_data = priv->plat->mdio_bus_data;
558 	struct device_node *mdio_node = priv->plat->mdio_node;
559 	struct device *dev = ndev->dev.parent;
560 	struct fwnode_handle *fixed_node;
561 	struct fwnode_handle *fwnode;
562 	int addr, found, max_addr;
563 
564 	if (!mdio_bus_data)
565 		return 0;
566 
567 	new_bus = mdiobus_alloc();
568 	if (!new_bus)
569 		return -ENOMEM;
570 
571 	if (mdio_bus_data->irqs)
572 		memcpy(new_bus->irq, mdio_bus_data->irqs, sizeof(new_bus->irq));
573 
574 	new_bus->name = "stmmac";
575 
576 	if (priv->plat->has_xgmac) {
577 		new_bus->read = &stmmac_xgmac2_mdio_read_c22;
578 		new_bus->write = &stmmac_xgmac2_mdio_write_c22;
579 		new_bus->read_c45 = &stmmac_xgmac2_mdio_read_c45;
580 		new_bus->write_c45 = &stmmac_xgmac2_mdio_write_c45;
581 
582 		if (priv->synopsys_id < DWXGMAC_CORE_2_20) {
583 			/* Right now only C22 phys are supported */
584 			max_addr = MII_XGMAC_MAX_C22ADDR + 1;
585 
586 			/* Check if DT specified an unsupported phy addr */
587 			if (priv->plat->phy_addr > MII_XGMAC_MAX_C22ADDR)
588 				dev_err(dev, "Unsupported phy_addr (max=%d)\n",
589 					MII_XGMAC_MAX_C22ADDR);
590 		} else {
591 			/* XGMAC version 2.20 onwards support 32 phy addr */
592 			max_addr = PHY_MAX_ADDR;
593 		}
594 	} else {
595 		new_bus->read = &stmmac_mdio_read_c22;
596 		new_bus->write = &stmmac_mdio_write_c22;
597 		if (priv->plat->has_gmac4) {
598 			new_bus->read_c45 = &stmmac_mdio_read_c45;
599 			new_bus->write_c45 = &stmmac_mdio_write_c45;
600 		}
601 
602 		max_addr = PHY_MAX_ADDR;
603 	}
604 
605 	if (mdio_bus_data->needs_reset)
606 		new_bus->reset = &stmmac_mdio_reset;
607 
608 	snprintf(new_bus->id, MII_BUS_ID_SIZE, "%s-%x",
609 		 new_bus->name, priv->plat->bus_id);
610 	new_bus->priv = ndev;
611 	new_bus->phy_mask = mdio_bus_data->phy_mask | mdio_bus_data->pcs_mask;
612 	new_bus->parent = priv->device;
613 
614 	err = of_mdiobus_register(new_bus, mdio_node);
615 	if (err == -ENODEV) {
616 		err = 0;
617 		dev_info(dev, "MDIO bus is disabled\n");
618 		goto bus_register_fail;
619 	} else if (err) {
620 		dev_err_probe(dev, err, "Cannot register the MDIO bus\n");
621 		goto bus_register_fail;
622 	}
623 
624 	/* Looks like we need a dummy read for XGMAC only and C45 PHYs */
625 	if (priv->plat->has_xgmac)
626 		stmmac_xgmac2_mdio_read_c45(new_bus, 0, 0, 0);
627 
628 	/* If fixed-link is set, skip PHY scanning */
629 	fwnode = priv->plat->port_node;
630 	if (!fwnode)
631 		fwnode = dev_fwnode(priv->device);
632 
633 	if (fwnode) {
634 		fixed_node = fwnode_get_named_child_node(fwnode, "fixed-link");
635 		if (fixed_node) {
636 			fwnode_handle_put(fixed_node);
637 			goto bus_register_done;
638 		}
639 	}
640 
641 	if (priv->plat->phy_node || mdio_node)
642 		goto bus_register_done;
643 
644 	found = 0;
645 	for (addr = 0; addr < max_addr; addr++) {
646 		struct phy_device *phydev = mdiobus_get_phy(new_bus, addr);
647 
648 		if (!phydev)
649 			continue;
650 
651 		/*
652 		 * If an IRQ was provided to be assigned after
653 		 * the bus probe, do it here.
654 		 */
655 		if (!mdio_bus_data->irqs &&
656 		    (mdio_bus_data->probed_phy_irq > 0)) {
657 			new_bus->irq[addr] = mdio_bus_data->probed_phy_irq;
658 			phydev->irq = mdio_bus_data->probed_phy_irq;
659 		}
660 
661 		/*
662 		 * If we're going to bind the MAC to this PHY bus,
663 		 * and no PHY number was provided to the MAC,
664 		 * use the one probed here.
665 		 */
666 		if (priv->plat->phy_addr == -1)
667 			priv->plat->phy_addr = addr;
668 
669 		phy_attached_info(phydev);
670 		found = 1;
671 	}
672 
673 	if (!found && !mdio_node) {
674 		dev_warn(dev, "No PHY found\n");
675 		err = -ENODEV;
676 		goto no_phy_found;
677 	}
678 
679 bus_register_done:
680 	priv->mii = new_bus;
681 
682 	return 0;
683 
684 no_phy_found:
685 	mdiobus_unregister(new_bus);
686 bus_register_fail:
687 	mdiobus_free(new_bus);
688 	return err;
689 }
690 
691 /**
692  * stmmac_mdio_unregister
693  * @ndev: net device structure
694  * Description: it unregisters the MII bus
695  */
696 int stmmac_mdio_unregister(struct net_device *ndev)
697 {
698 	struct stmmac_priv *priv = netdev_priv(ndev);
699 
700 	if (!priv->mii)
701 		return 0;
702 
703 	mdiobus_unregister(priv->mii);
704 	priv->mii->priv = NULL;
705 	mdiobus_free(priv->mii);
706 	priv->mii = NULL;
707 
708 	return 0;
709 }
710