xref: /linux/drivers/net/phy/phy.c (revision 47da88f36639b8de57f6cdd680f8c27528ccd67c)
1 /*
2  * drivers/net/phy/phy.c
3  *
4  * Framework for configuring and reading PHY devices
5  * Based on code in sungem_phy.c and gianfar_phy.c
6  *
7  * Author: Andy Fleming
8  *
9  * Copyright (c) 2004 Freescale Semiconductor, Inc.
10  * Copyright (c) 2006, 2007  Maciej W. Rozycki
11  *
12  * This program is free software; you can redistribute  it and/or modify it
13  * under  the terms of  the GNU General  Public License as published by the
14  * Free Software Foundation;  either version 2 of the  License, or (at your
15  * option) any later version.
16  *
17  */
18 #include <linux/kernel.h>
19 #include <linux/string.h>
20 #include <linux/errno.h>
21 #include <linux/unistd.h>
22 #include <linux/interrupt.h>
23 #include <linux/init.h>
24 #include <linux/delay.h>
25 #include <linux/netdevice.h>
26 #include <linux/etherdevice.h>
27 #include <linux/skbuff.h>
28 #include <linux/mm.h>
29 #include <linux/module.h>
30 #include <linux/mii.h>
31 #include <linux/ethtool.h>
32 #include <linux/phy.h>
33 #include <linux/timer.h>
34 #include <linux/workqueue.h>
35 
36 #include <asm/atomic.h>
37 #include <asm/io.h>
38 #include <asm/irq.h>
39 #include <asm/uaccess.h>
40 
41 /**
42  * phy_print_status - Convenience function to print out the current phy status
43  * @phydev: the phy_device struct
44  */
45 void phy_print_status(struct phy_device *phydev)
46 {
47 	pr_info("PHY: %s - Link is %s", dev_name(&phydev->dev),
48 			phydev->link ? "Up" : "Down");
49 	if (phydev->link)
50 		printk(" - %d/%s", phydev->speed,
51 				DUPLEX_FULL == phydev->duplex ?
52 				"Full" : "Half");
53 
54 	printk("\n");
55 }
56 EXPORT_SYMBOL(phy_print_status);
57 
58 
59 /**
60  * phy_clear_interrupt - Ack the phy device's interrupt
61  * @phydev: the phy_device struct
62  *
63  * If the @phydev driver has an ack_interrupt function, call it to
64  * ack and clear the phy device's interrupt.
65  *
66  * Returns 0 on success on < 0 on error.
67  */
68 int phy_clear_interrupt(struct phy_device *phydev)
69 {
70 	int err = 0;
71 
72 	if (phydev->drv->ack_interrupt)
73 		err = phydev->drv->ack_interrupt(phydev);
74 
75 	return err;
76 }
77 
78 /**
79  * phy_config_interrupt - configure the PHY device for the requested interrupts
80  * @phydev: the phy_device struct
81  * @interrupts: interrupt flags to configure for this @phydev
82  *
83  * Returns 0 on success on < 0 on error.
84  */
85 int phy_config_interrupt(struct phy_device *phydev, u32 interrupts)
86 {
87 	int err = 0;
88 
89 	phydev->interrupts = interrupts;
90 	if (phydev->drv->config_intr)
91 		err = phydev->drv->config_intr(phydev);
92 
93 	return err;
94 }
95 
96 
97 /**
98  * phy_aneg_done - return auto-negotiation status
99  * @phydev: target phy_device struct
100  *
101  * Description: Reads the status register and returns 0 either if
102  *   auto-negotiation is incomplete, or if there was an error.
103  *   Returns BMSR_ANEGCOMPLETE if auto-negotiation is done.
104  */
105 static inline int phy_aneg_done(struct phy_device *phydev)
106 {
107 	int retval;
108 
109 	retval = phy_read(phydev, MII_BMSR);
110 
111 	return (retval < 0) ? retval : (retval & BMSR_ANEGCOMPLETE);
112 }
113 
114 /* A structure for mapping a particular speed and duplex
115  * combination to a particular SUPPORTED and ADVERTISED value */
116 struct phy_setting {
117 	int speed;
118 	int duplex;
119 	u32 setting;
120 };
121 
122 /* A mapping of all SUPPORTED settings to speed/duplex */
123 static const struct phy_setting settings[] = {
124 	{
125 		.speed = 10000,
126 		.duplex = DUPLEX_FULL,
127 		.setting = SUPPORTED_10000baseT_Full,
128 	},
129 	{
130 		.speed = SPEED_1000,
131 		.duplex = DUPLEX_FULL,
132 		.setting = SUPPORTED_1000baseT_Full,
133 	},
134 	{
135 		.speed = SPEED_1000,
136 		.duplex = DUPLEX_HALF,
137 		.setting = SUPPORTED_1000baseT_Half,
138 	},
139 	{
140 		.speed = SPEED_100,
141 		.duplex = DUPLEX_FULL,
142 		.setting = SUPPORTED_100baseT_Full,
143 	},
144 	{
145 		.speed = SPEED_100,
146 		.duplex = DUPLEX_HALF,
147 		.setting = SUPPORTED_100baseT_Half,
148 	},
149 	{
150 		.speed = SPEED_10,
151 		.duplex = DUPLEX_FULL,
152 		.setting = SUPPORTED_10baseT_Full,
153 	},
154 	{
155 		.speed = SPEED_10,
156 		.duplex = DUPLEX_HALF,
157 		.setting = SUPPORTED_10baseT_Half,
158 	},
159 };
160 
161 #define MAX_NUM_SETTINGS ARRAY_SIZE(settings)
162 
163 /**
164  * phy_find_setting - find a PHY settings array entry that matches speed & duplex
165  * @speed: speed to match
166  * @duplex: duplex to match
167  *
168  * Description: Searches the settings array for the setting which
169  *   matches the desired speed and duplex, and returns the index
170  *   of that setting.  Returns the index of the last setting if
171  *   none of the others match.
172  */
173 static inline int phy_find_setting(int speed, int duplex)
174 {
175 	int idx = 0;
176 
177 	while (idx < ARRAY_SIZE(settings) &&
178 			(settings[idx].speed != speed ||
179 			settings[idx].duplex != duplex))
180 		idx++;
181 
182 	return idx < MAX_NUM_SETTINGS ? idx : MAX_NUM_SETTINGS - 1;
183 }
184 
185 /**
186  * phy_find_valid - find a PHY setting that matches the requested features mask
187  * @idx: The first index in settings[] to search
188  * @features: A mask of the valid settings
189  *
190  * Description: Returns the index of the first valid setting less
191  *   than or equal to the one pointed to by idx, as determined by
192  *   the mask in features.  Returns the index of the last setting
193  *   if nothing else matches.
194  */
195 static inline int phy_find_valid(int idx, u32 features)
196 {
197 	while (idx < MAX_NUM_SETTINGS && !(settings[idx].setting & features))
198 		idx++;
199 
200 	return idx < MAX_NUM_SETTINGS ? idx : MAX_NUM_SETTINGS - 1;
201 }
202 
203 /**
204  * phy_sanitize_settings - make sure the PHY is set to supported speed and duplex
205  * @phydev: the target phy_device struct
206  *
207  * Description: Make sure the PHY is set to supported speeds and
208  *   duplexes.  Drop down by one in this order:  1000/FULL,
209  *   1000/HALF, 100/FULL, 100/HALF, 10/FULL, 10/HALF.
210  */
211 void phy_sanitize_settings(struct phy_device *phydev)
212 {
213 	u32 features = phydev->supported;
214 	int idx;
215 
216 	/* Sanitize settings based on PHY capabilities */
217 	if ((features & SUPPORTED_Autoneg) == 0)
218 		phydev->autoneg = AUTONEG_DISABLE;
219 
220 	idx = phy_find_valid(phy_find_setting(phydev->speed, phydev->duplex),
221 			features);
222 
223 	phydev->speed = settings[idx].speed;
224 	phydev->duplex = settings[idx].duplex;
225 }
226 EXPORT_SYMBOL(phy_sanitize_settings);
227 
228 /**
229  * phy_ethtool_sset - generic ethtool sset function, handles all the details
230  * @phydev: target phy_device struct
231  * @cmd: ethtool_cmd
232  *
233  * A few notes about parameter checking:
234  * - We don't set port or transceiver, so we don't care what they
235  *   were set to.
236  * - phy_start_aneg() will make sure forced settings are sane, and
237  *   choose the next best ones from the ones selected, so we don't
238  *   care if ethtool tries to give us bad values.
239  */
240 int phy_ethtool_sset(struct phy_device *phydev, struct ethtool_cmd *cmd)
241 {
242 	if (cmd->phy_address != phydev->addr)
243 		return -EINVAL;
244 
245 	/* We make sure that we don't pass unsupported
246 	 * values in to the PHY */
247 	cmd->advertising &= phydev->supported;
248 
249 	/* Verify the settings we care about. */
250 	if (cmd->autoneg != AUTONEG_ENABLE && cmd->autoneg != AUTONEG_DISABLE)
251 		return -EINVAL;
252 
253 	if (cmd->autoneg == AUTONEG_ENABLE && cmd->advertising == 0)
254 		return -EINVAL;
255 
256 	if (cmd->autoneg == AUTONEG_DISABLE &&
257 	    ((cmd->speed != SPEED_1000 &&
258 	      cmd->speed != SPEED_100 &&
259 	      cmd->speed != SPEED_10) ||
260 	     (cmd->duplex != DUPLEX_HALF &&
261 	      cmd->duplex != DUPLEX_FULL)))
262 		return -EINVAL;
263 
264 	phydev->autoneg = cmd->autoneg;
265 
266 	phydev->speed = cmd->speed;
267 
268 	phydev->advertising = cmd->advertising;
269 
270 	if (AUTONEG_ENABLE == cmd->autoneg)
271 		phydev->advertising |= ADVERTISED_Autoneg;
272 	else
273 		phydev->advertising &= ~ADVERTISED_Autoneg;
274 
275 	phydev->duplex = cmd->duplex;
276 
277 	/* Restart the PHY */
278 	phy_start_aneg(phydev);
279 
280 	return 0;
281 }
282 EXPORT_SYMBOL(phy_ethtool_sset);
283 
284 int phy_ethtool_gset(struct phy_device *phydev, struct ethtool_cmd *cmd)
285 {
286 	cmd->supported = phydev->supported;
287 
288 	cmd->advertising = phydev->advertising;
289 
290 	cmd->speed = phydev->speed;
291 	cmd->duplex = phydev->duplex;
292 	cmd->port = PORT_MII;
293 	cmd->phy_address = phydev->addr;
294 	cmd->transceiver = XCVR_EXTERNAL;
295 	cmd->autoneg = phydev->autoneg;
296 
297 	return 0;
298 }
299 EXPORT_SYMBOL(phy_ethtool_gset);
300 
301 /**
302  * phy_mii_ioctl - generic PHY MII ioctl interface
303  * @phydev: the phy_device struct
304  * @ifr: &struct ifreq for socket ioctl's
305  * @cmd: ioctl cmd to execute
306  *
307  * Note that this function is currently incompatible with the
308  * PHYCONTROL layer.  It changes registers without regard to
309  * current state.  Use at own risk.
310  */
311 int phy_mii_ioctl(struct phy_device *phydev,
312 		struct ifreq *ifr, int cmd)
313 {
314 	struct mii_ioctl_data *mii_data = if_mii(ifr);
315 	u16 val = mii_data->val_in;
316 
317 	switch (cmd) {
318 	case SIOCGMIIPHY:
319 		mii_data->phy_id = phydev->addr;
320 		/* fall through */
321 
322 	case SIOCGMIIREG:
323 		mii_data->val_out = phy_read(phydev, mii_data->reg_num);
324 		break;
325 
326 	case SIOCSMIIREG:
327 		if (mii_data->phy_id == phydev->addr) {
328 			switch(mii_data->reg_num) {
329 			case MII_BMCR:
330 				if ((val & (BMCR_RESET|BMCR_ANENABLE)) == 0)
331 					phydev->autoneg = AUTONEG_DISABLE;
332 				else
333 					phydev->autoneg = AUTONEG_ENABLE;
334 				if ((!phydev->autoneg) && (val & BMCR_FULLDPLX))
335 					phydev->duplex = DUPLEX_FULL;
336 				else
337 					phydev->duplex = DUPLEX_HALF;
338 				if ((!phydev->autoneg) &&
339 						(val & BMCR_SPEED1000))
340 					phydev->speed = SPEED_1000;
341 				else if ((!phydev->autoneg) &&
342 						(val & BMCR_SPEED100))
343 					phydev->speed = SPEED_100;
344 				break;
345 			case MII_ADVERTISE:
346 				phydev->advertising = val;
347 				break;
348 			default:
349 				/* do nothing */
350 				break;
351 			}
352 		}
353 
354 		phy_write(phydev, mii_data->reg_num, val);
355 
356 		if (mii_data->reg_num == MII_BMCR &&
357 		    val & BMCR_RESET &&
358 		    phydev->drv->config_init) {
359 			phy_scan_fixups(phydev);
360 			phydev->drv->config_init(phydev);
361 		}
362 		break;
363 
364 	case SIOCSHWTSTAMP:
365 		if (phydev->drv->hwtstamp)
366 			return phydev->drv->hwtstamp(phydev, ifr);
367 		/* fall through */
368 
369 	default:
370 		return -EOPNOTSUPP;
371 	}
372 
373 	return 0;
374 }
375 EXPORT_SYMBOL(phy_mii_ioctl);
376 
377 /**
378  * phy_start_aneg - start auto-negotiation for this PHY device
379  * @phydev: the phy_device struct
380  *
381  * Description: Sanitizes the settings (if we're not autonegotiating
382  *   them), and then calls the driver's config_aneg function.
383  *   If the PHYCONTROL Layer is operating, we change the state to
384  *   reflect the beginning of Auto-negotiation or forcing.
385  */
386 int phy_start_aneg(struct phy_device *phydev)
387 {
388 	int err;
389 
390 	mutex_lock(&phydev->lock);
391 
392 	if (AUTONEG_DISABLE == phydev->autoneg)
393 		phy_sanitize_settings(phydev);
394 
395 	err = phydev->drv->config_aneg(phydev);
396 
397 	if (err < 0)
398 		goto out_unlock;
399 
400 	if (phydev->state != PHY_HALTED) {
401 		if (AUTONEG_ENABLE == phydev->autoneg) {
402 			phydev->state = PHY_AN;
403 			phydev->link_timeout = PHY_AN_TIMEOUT;
404 		} else {
405 			phydev->state = PHY_FORCING;
406 			phydev->link_timeout = PHY_FORCE_TIMEOUT;
407 		}
408 	}
409 
410 out_unlock:
411 	mutex_unlock(&phydev->lock);
412 	return err;
413 }
414 EXPORT_SYMBOL(phy_start_aneg);
415 
416 
417 static void phy_change(struct work_struct *work);
418 
419 /**
420  * phy_start_machine - start PHY state machine tracking
421  * @phydev: the phy_device struct
422  * @handler: callback function for state change notifications
423  *
424  * Description: The PHY infrastructure can run a state machine
425  *   which tracks whether the PHY is starting up, negotiating,
426  *   etc.  This function starts the timer which tracks the state
427  *   of the PHY.  If you want to be notified when the state changes,
428  *   pass in the callback @handler, otherwise, pass NULL.  If you
429  *   want to maintain your own state machine, do not call this
430  *   function.
431  */
432 void phy_start_machine(struct phy_device *phydev,
433 		void (*handler)(struct net_device *))
434 {
435 	phydev->adjust_state = handler;
436 
437 	schedule_delayed_work(&phydev->state_queue, HZ);
438 }
439 
440 /**
441  * phy_stop_machine - stop the PHY state machine tracking
442  * @phydev: target phy_device struct
443  *
444  * Description: Stops the state machine timer, sets the state to UP
445  *   (unless it wasn't up yet). This function must be called BEFORE
446  *   phy_detach.
447  */
448 void phy_stop_machine(struct phy_device *phydev)
449 {
450 	cancel_delayed_work_sync(&phydev->state_queue);
451 
452 	mutex_lock(&phydev->lock);
453 	if (phydev->state > PHY_UP)
454 		phydev->state = PHY_UP;
455 	mutex_unlock(&phydev->lock);
456 
457 	phydev->adjust_state = NULL;
458 }
459 
460 /**
461  * phy_force_reduction - reduce PHY speed/duplex settings by one step
462  * @phydev: target phy_device struct
463  *
464  * Description: Reduces the speed/duplex settings by one notch,
465  *   in this order--
466  *   1000/FULL, 1000/HALF, 100/FULL, 100/HALF, 10/FULL, 10/HALF.
467  *   The function bottoms out at 10/HALF.
468  */
469 static void phy_force_reduction(struct phy_device *phydev)
470 {
471 	int idx;
472 
473 	idx = phy_find_setting(phydev->speed, phydev->duplex);
474 
475 	idx++;
476 
477 	idx = phy_find_valid(idx, phydev->supported);
478 
479 	phydev->speed = settings[idx].speed;
480 	phydev->duplex = settings[idx].duplex;
481 
482 	pr_info("Trying %d/%s\n", phydev->speed,
483 			DUPLEX_FULL == phydev->duplex ?
484 			"FULL" : "HALF");
485 }
486 
487 
488 /**
489  * phy_error - enter HALTED state for this PHY device
490  * @phydev: target phy_device struct
491  *
492  * Moves the PHY to the HALTED state in response to a read
493  * or write error, and tells the controller the link is down.
494  * Must not be called from interrupt context, or while the
495  * phydev->lock is held.
496  */
497 static void phy_error(struct phy_device *phydev)
498 {
499 	mutex_lock(&phydev->lock);
500 	phydev->state = PHY_HALTED;
501 	mutex_unlock(&phydev->lock);
502 }
503 
504 /**
505  * phy_interrupt - PHY interrupt handler
506  * @irq: interrupt line
507  * @phy_dat: phy_device pointer
508  *
509  * Description: When a PHY interrupt occurs, the handler disables
510  * interrupts, and schedules a work task to clear the interrupt.
511  */
512 static irqreturn_t phy_interrupt(int irq, void *phy_dat)
513 {
514 	struct phy_device *phydev = phy_dat;
515 
516 	if (PHY_HALTED == phydev->state)
517 		return IRQ_NONE;		/* It can't be ours.  */
518 
519 	/* The MDIO bus is not allowed to be written in interrupt
520 	 * context, so we need to disable the irq here.  A work
521 	 * queue will write the PHY to disable and clear the
522 	 * interrupt, and then reenable the irq line. */
523 	disable_irq_nosync(irq);
524 	atomic_inc(&phydev->irq_disable);
525 
526 	schedule_work(&phydev->phy_queue);
527 
528 	return IRQ_HANDLED;
529 }
530 
531 /**
532  * phy_enable_interrupts - Enable the interrupts from the PHY side
533  * @phydev: target phy_device struct
534  */
535 int phy_enable_interrupts(struct phy_device *phydev)
536 {
537 	int err;
538 
539 	err = phy_clear_interrupt(phydev);
540 
541 	if (err < 0)
542 		return err;
543 
544 	err = phy_config_interrupt(phydev, PHY_INTERRUPT_ENABLED);
545 
546 	return err;
547 }
548 EXPORT_SYMBOL(phy_enable_interrupts);
549 
550 /**
551  * phy_disable_interrupts - Disable the PHY interrupts from the PHY side
552  * @phydev: target phy_device struct
553  */
554 int phy_disable_interrupts(struct phy_device *phydev)
555 {
556 	int err;
557 
558 	/* Disable PHY interrupts */
559 	err = phy_config_interrupt(phydev, PHY_INTERRUPT_DISABLED);
560 
561 	if (err)
562 		goto phy_err;
563 
564 	/* Clear the interrupt */
565 	err = phy_clear_interrupt(phydev);
566 
567 	if (err)
568 		goto phy_err;
569 
570 	return 0;
571 
572 phy_err:
573 	phy_error(phydev);
574 
575 	return err;
576 }
577 EXPORT_SYMBOL(phy_disable_interrupts);
578 
579 /**
580  * phy_start_interrupts - request and enable interrupts for a PHY device
581  * @phydev: target phy_device struct
582  *
583  * Description: Request the interrupt for the given PHY.
584  *   If this fails, then we set irq to PHY_POLL.
585  *   Otherwise, we enable the interrupts in the PHY.
586  *   This should only be called with a valid IRQ number.
587  *   Returns 0 on success or < 0 on error.
588  */
589 int phy_start_interrupts(struct phy_device *phydev)
590 {
591 	int err = 0;
592 
593 	INIT_WORK(&phydev->phy_queue, phy_change);
594 
595 	atomic_set(&phydev->irq_disable, 0);
596 	if (request_irq(phydev->irq, phy_interrupt,
597 				IRQF_SHARED,
598 				"phy_interrupt",
599 				phydev) < 0) {
600 		printk(KERN_WARNING "%s: Can't get IRQ %d (PHY)\n",
601 				phydev->bus->name,
602 				phydev->irq);
603 		phydev->irq = PHY_POLL;
604 		return 0;
605 	}
606 
607 	err = phy_enable_interrupts(phydev);
608 
609 	return err;
610 }
611 EXPORT_SYMBOL(phy_start_interrupts);
612 
613 /**
614  * phy_stop_interrupts - disable interrupts from a PHY device
615  * @phydev: target phy_device struct
616  */
617 int phy_stop_interrupts(struct phy_device *phydev)
618 {
619 	int err;
620 
621 	err = phy_disable_interrupts(phydev);
622 
623 	if (err)
624 		phy_error(phydev);
625 
626 	free_irq(phydev->irq, phydev);
627 
628 	/*
629 	 * Cannot call flush_scheduled_work() here as desired because
630 	 * of rtnl_lock(), but we do not really care about what would
631 	 * be done, except from enable_irq(), so cancel any work
632 	 * possibly pending and take care of the matter below.
633 	 */
634 	cancel_work_sync(&phydev->phy_queue);
635 	/*
636 	 * If work indeed has been cancelled, disable_irq() will have
637 	 * been left unbalanced from phy_interrupt() and enable_irq()
638 	 * has to be called so that other devices on the line work.
639 	 */
640 	while (atomic_dec_return(&phydev->irq_disable) >= 0)
641 		enable_irq(phydev->irq);
642 
643 	return err;
644 }
645 EXPORT_SYMBOL(phy_stop_interrupts);
646 
647 
648 /**
649  * phy_change - Scheduled by the phy_interrupt/timer to handle PHY changes
650  * @work: work_struct that describes the work to be done
651  */
652 static void phy_change(struct work_struct *work)
653 {
654 	int err;
655 	struct phy_device *phydev =
656 		container_of(work, struct phy_device, phy_queue);
657 
658 	if (phydev->drv->did_interrupt &&
659 	    !phydev->drv->did_interrupt(phydev))
660 		goto ignore;
661 
662 	err = phy_disable_interrupts(phydev);
663 
664 	if (err)
665 		goto phy_err;
666 
667 	mutex_lock(&phydev->lock);
668 	if ((PHY_RUNNING == phydev->state) || (PHY_NOLINK == phydev->state))
669 		phydev->state = PHY_CHANGELINK;
670 	mutex_unlock(&phydev->lock);
671 
672 	atomic_dec(&phydev->irq_disable);
673 	enable_irq(phydev->irq);
674 
675 	/* Reenable interrupts */
676 	if (PHY_HALTED != phydev->state)
677 		err = phy_config_interrupt(phydev, PHY_INTERRUPT_ENABLED);
678 
679 	if (err)
680 		goto irq_enable_err;
681 
682 	/* reschedule state queue work to run as soon as possible */
683 	cancel_delayed_work_sync(&phydev->state_queue);
684 	schedule_delayed_work(&phydev->state_queue, 0);
685 
686 	return;
687 
688 ignore:
689 	atomic_dec(&phydev->irq_disable);
690 	enable_irq(phydev->irq);
691 	return;
692 
693 irq_enable_err:
694 	disable_irq(phydev->irq);
695 	atomic_inc(&phydev->irq_disable);
696 phy_err:
697 	phy_error(phydev);
698 }
699 
700 /**
701  * phy_stop - Bring down the PHY link, and stop checking the status
702  * @phydev: target phy_device struct
703  */
704 void phy_stop(struct phy_device *phydev)
705 {
706 	mutex_lock(&phydev->lock);
707 
708 	if (PHY_HALTED == phydev->state)
709 		goto out_unlock;
710 
711 	if (phydev->irq != PHY_POLL) {
712 		/* Disable PHY Interrupts */
713 		phy_config_interrupt(phydev, PHY_INTERRUPT_DISABLED);
714 
715 		/* Clear any pending interrupts */
716 		phy_clear_interrupt(phydev);
717 	}
718 
719 	phydev->state = PHY_HALTED;
720 
721 out_unlock:
722 	mutex_unlock(&phydev->lock);
723 
724 	/*
725 	 * Cannot call flush_scheduled_work() here as desired because
726 	 * of rtnl_lock(), but PHY_HALTED shall guarantee phy_change()
727 	 * will not reenable interrupts.
728 	 */
729 }
730 
731 
732 /**
733  * phy_start - start or restart a PHY device
734  * @phydev: target phy_device struct
735  *
736  * Description: Indicates the attached device's readiness to
737  *   handle PHY-related work.  Used during startup to start the
738  *   PHY, and after a call to phy_stop() to resume operation.
739  *   Also used to indicate the MDIO bus has cleared an error
740  *   condition.
741  */
742 void phy_start(struct phy_device *phydev)
743 {
744 	mutex_lock(&phydev->lock);
745 
746 	switch (phydev->state) {
747 		case PHY_STARTING:
748 			phydev->state = PHY_PENDING;
749 			break;
750 		case PHY_READY:
751 			phydev->state = PHY_UP;
752 			break;
753 		case PHY_HALTED:
754 			phydev->state = PHY_RESUMING;
755 		default:
756 			break;
757 	}
758 	mutex_unlock(&phydev->lock);
759 }
760 EXPORT_SYMBOL(phy_stop);
761 EXPORT_SYMBOL(phy_start);
762 
763 /**
764  * phy_state_machine - Handle the state machine
765  * @work: work_struct that describes the work to be done
766  */
767 void phy_state_machine(struct work_struct *work)
768 {
769 	struct delayed_work *dwork = to_delayed_work(work);
770 	struct phy_device *phydev =
771 			container_of(dwork, struct phy_device, state_queue);
772 	int needs_aneg = 0;
773 	int err = 0;
774 
775 	mutex_lock(&phydev->lock);
776 
777 	if (phydev->adjust_state)
778 		phydev->adjust_state(phydev->attached_dev);
779 
780 	switch(phydev->state) {
781 		case PHY_DOWN:
782 		case PHY_STARTING:
783 		case PHY_READY:
784 		case PHY_PENDING:
785 			break;
786 		case PHY_UP:
787 			needs_aneg = 1;
788 
789 			phydev->link_timeout = PHY_AN_TIMEOUT;
790 
791 			break;
792 		case PHY_AN:
793 			err = phy_read_status(phydev);
794 
795 			if (err < 0)
796 				break;
797 
798 			/* If the link is down, give up on
799 			 * negotiation for now */
800 			if (!phydev->link) {
801 				phydev->state = PHY_NOLINK;
802 				netif_carrier_off(phydev->attached_dev);
803 				phydev->adjust_link(phydev->attached_dev);
804 				break;
805 			}
806 
807 			/* Check if negotiation is done.  Break
808 			 * if there's an error */
809 			err = phy_aneg_done(phydev);
810 			if (err < 0)
811 				break;
812 
813 			/* If AN is done, we're running */
814 			if (err > 0) {
815 				phydev->state = PHY_RUNNING;
816 				netif_carrier_on(phydev->attached_dev);
817 				phydev->adjust_link(phydev->attached_dev);
818 
819 			} else if (0 == phydev->link_timeout--) {
820 				int idx;
821 
822 				needs_aneg = 1;
823 				/* If we have the magic_aneg bit,
824 				 * we try again */
825 				if (phydev->drv->flags & PHY_HAS_MAGICANEG)
826 					break;
827 
828 				/* The timer expired, and we still
829 				 * don't have a setting, so we try
830 				 * forcing it until we find one that
831 				 * works, starting from the fastest speed,
832 				 * and working our way down */
833 				idx = phy_find_valid(0, phydev->supported);
834 
835 				phydev->speed = settings[idx].speed;
836 				phydev->duplex = settings[idx].duplex;
837 
838 				phydev->autoneg = AUTONEG_DISABLE;
839 
840 				pr_info("Trying %d/%s\n", phydev->speed,
841 						DUPLEX_FULL ==
842 						phydev->duplex ?
843 						"FULL" : "HALF");
844 			}
845 			break;
846 		case PHY_NOLINK:
847 			err = phy_read_status(phydev);
848 
849 			if (err)
850 				break;
851 
852 			if (phydev->link) {
853 				phydev->state = PHY_RUNNING;
854 				netif_carrier_on(phydev->attached_dev);
855 				phydev->adjust_link(phydev->attached_dev);
856 			}
857 			break;
858 		case PHY_FORCING:
859 			err = genphy_update_link(phydev);
860 
861 			if (err)
862 				break;
863 
864 			if (phydev->link) {
865 				phydev->state = PHY_RUNNING;
866 				netif_carrier_on(phydev->attached_dev);
867 			} else {
868 				if (0 == phydev->link_timeout--) {
869 					phy_force_reduction(phydev);
870 					needs_aneg = 1;
871 				}
872 			}
873 
874 			phydev->adjust_link(phydev->attached_dev);
875 			break;
876 		case PHY_RUNNING:
877 			/* Only register a CHANGE if we are
878 			 * polling */
879 			if (PHY_POLL == phydev->irq)
880 				phydev->state = PHY_CHANGELINK;
881 			break;
882 		case PHY_CHANGELINK:
883 			err = phy_read_status(phydev);
884 
885 			if (err)
886 				break;
887 
888 			if (phydev->link) {
889 				phydev->state = PHY_RUNNING;
890 				netif_carrier_on(phydev->attached_dev);
891 			} else {
892 				phydev->state = PHY_NOLINK;
893 				netif_carrier_off(phydev->attached_dev);
894 			}
895 
896 			phydev->adjust_link(phydev->attached_dev);
897 
898 			if (PHY_POLL != phydev->irq)
899 				err = phy_config_interrupt(phydev,
900 						PHY_INTERRUPT_ENABLED);
901 			break;
902 		case PHY_HALTED:
903 			if (phydev->link) {
904 				phydev->link = 0;
905 				netif_carrier_off(phydev->attached_dev);
906 				phydev->adjust_link(phydev->attached_dev);
907 			}
908 			break;
909 		case PHY_RESUMING:
910 
911 			err = phy_clear_interrupt(phydev);
912 
913 			if (err)
914 				break;
915 
916 			err = phy_config_interrupt(phydev,
917 					PHY_INTERRUPT_ENABLED);
918 
919 			if (err)
920 				break;
921 
922 			if (AUTONEG_ENABLE == phydev->autoneg) {
923 				err = phy_aneg_done(phydev);
924 				if (err < 0)
925 					break;
926 
927 				/* err > 0 if AN is done.
928 				 * Otherwise, it's 0, and we're
929 				 * still waiting for AN */
930 				if (err > 0) {
931 					err = phy_read_status(phydev);
932 					if (err)
933 						break;
934 
935 					if (phydev->link) {
936 						phydev->state = PHY_RUNNING;
937 						netif_carrier_on(phydev->attached_dev);
938 					} else
939 						phydev->state = PHY_NOLINK;
940 					phydev->adjust_link(phydev->attached_dev);
941 				} else {
942 					phydev->state = PHY_AN;
943 					phydev->link_timeout = PHY_AN_TIMEOUT;
944 				}
945 			} else {
946 				err = phy_read_status(phydev);
947 				if (err)
948 					break;
949 
950 				if (phydev->link) {
951 					phydev->state = PHY_RUNNING;
952 					netif_carrier_on(phydev->attached_dev);
953 				} else
954 					phydev->state = PHY_NOLINK;
955 				phydev->adjust_link(phydev->attached_dev);
956 			}
957 			break;
958 	}
959 
960 	mutex_unlock(&phydev->lock);
961 
962 	if (needs_aneg)
963 		err = phy_start_aneg(phydev);
964 
965 	if (err < 0)
966 		phy_error(phydev);
967 
968 	schedule_delayed_work(&phydev->state_queue, PHY_STATE_TIME * HZ);
969 }
970