aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/net/phy/phy.c
blob: 9bc11773705b2beaf68064e6ba3166953c20a5f6 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
/*
 * drivers/net/phy/phy.c
 *
 * Framework for configuring and reading PHY devices
 * Based on code in sungem_phy.c and gianfar_phy.c
 *
 * Author: Andy Fleming
 *
 * Copyright (c) 2004 Freescale Semiconductor, Inc.
 * Copyright (c) 2006, 2007  Maciej W. Rozycki
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 *
 */
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/phy.h>
#include <linux/timer.h>
#include <linux/workqueue.h>

#include <asm/atomic.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>

/**
 * phy_print_status - Convenience function to print out the current phy status
 * @phydev: the phy_device struct
 */
void phy_print_status(struct phy_device *phydev)
{
	pr_info("PHY: %s - Link is %s", phydev->dev.bus_id,
			phydev->link ? "Up" : "Down");
	if (phydev->link)
		printk(" - %d/%s", phydev->speed,
				DUPLEX_FULL == phydev->duplex ?
				"Full" : "Half");

	printk("\n");
}
EXPORT_SYMBOL(phy_print_status);


/**
 * phy_read - Convenience function for reading a given PHY register
 * @phydev: the phy_device struct
 * @regnum: register number to read
 *
 * NOTE: MUST NOT be called from interrupt context,
 * because the bus read/write functions may wait for an interrupt
 * to conclude the operation.
 */
int phy_read(struct phy_device *phydev, u16 regnum)
{
	int retval;
	struct mii_bus *bus = phydev->bus;

	spin_lock_bh(&bus->mdio_lock);
	retval = bus->read(bus, phydev->addr, regnum);
	spin_unlock_bh(&bus->mdio_lock);

	return retval;
}
EXPORT_SYMBOL(phy_read);

/**
 * phy_write - Convenience function for writing a given PHY register
 * @phydev: the phy_device struct
 * @regnum: register number to write
 * @val: value to write to @regnum
 *
 * NOTE: MUST NOT be called from interrupt context,
 * because the bus read/write functions may wait for an interrupt
 * to conclude the operation.
 */
int phy_write(struct phy_device *phydev, u16 regnum, u16 val)
{
	int err;
	struct mii_bus *bus = phydev->bus;

	spin_lock_bh(&bus->mdio_lock);
	err = bus->write(bus, phydev->addr, regnum, val);
	spin_unlock_bh(&bus->mdio_lock);

	return err;
}
EXPORT_SYMBOL(phy_write);

/**
 * phy_clear_interrupt - Ack the phy device's interrupt
 * @phydev: the phy_device struct
 *
 * If the @phydev driver has an ack_interrupt function, call it to
 * ack and clear the phy device's interrupt.
 *
 * Returns 0 on success on < 0 on error.
 */
int phy_clear_interrupt(struct phy_device *phydev)
{
	int err = 0;

	if (phydev->drv->ack_interrupt)
		err = phydev->drv->ack_interrupt(phydev);

	return err;
}

/**
 * phy_config_interrupt - configure the PHY device for the requested interrupts
 * @phydev: the phy_device struct
 * @interrupts: interrupt flags to configure for this @phydev
 *
 * Returns 0 on success on < 0 on error.
 */
int phy_config_interrupt(struct phy_device *phydev, u32 interrupts)
{
	int err = 0;

	phydev->interrupts = interrupts;
	if (phydev->drv->config_intr)
		err = phydev->drv->config_intr(phydev);

	return err;
}


/**
 * phy_aneg_done - return auto-negotiation status
 * @phydev: target phy_device struct
 *
 * Description: Reads the status register and returns 0 either if
 *   auto-negotiation is incomplete, or if there was an error.
 *   Returns BMSR_ANEGCOMPLETE if auto-negotiation is done.
 */
static inline int phy_aneg_done(struct phy_device *phydev)
{
	int retval;

	retval = phy_read(phydev, MII_BMSR);

	return (retval < 0) ? retval : (retval & BMSR_ANEGCOMPLETE);
}

/* A structure for mapping a particular speed and duplex
 * combination to a particular SUPPORTED and ADVERTISED value */
struct phy_setting {
	int speed;
	int duplex;
	u32 setting;
};

/* A mapping of all SUPPORTED settings to speed/duplex */
static const struct phy_setting settings[] = {
	{
		.speed = 10000,
		.duplex = DUPLEX_FULL,
		.setting = SUPPORTED_10000baseT_Full,
	},
	{
		.speed = SPEED_1000,
		.duplex = DUPLEX_FULL,
		.setting = SUPPORTED_1000baseT_Full,
	},
	{
		.speed = SPEED_1000,
		.duplex = DUPLEX_HALF,
		.setting = SUPPORTED_1000baseT_Half,
	},
	{
		.speed = SPEED_100,
		.duplex = DUPLEX_FULL,
		.setting = SUPPORTED_100baseT_Full,
	},
	{
		.speed = SPEED_100,
		.duplex = DUPLEX_HALF,
		.setting = SUPPORTED_100baseT_Half,
	},
	{
		.speed = SPEED_10,
		.duplex = DUPLEX_FULL,
		.setting = SUPPORTED_10baseT_Full,
	},
	{
		.speed = SPEED_10,
		.duplex = DUPLEX_HALF,
		.setting = SUPPORTED_10baseT_Half,
	},
};

#define MAX_NUM_SETTINGS ARRAY_SIZE(settings)

/**
 * phy_find_setting - find a PHY settings array entry that matches speed & duplex
 * @speed: speed to match
 * @duplex: duplex to match
 *
 * Description: Searches the settings array for the setting which
 *   matches the desired speed and duplex, and returns the index
 *   of that setting.  Returns the index of the last setting if
 *   none of the others match.
 */
static inline int phy_find_setting(int speed, int duplex)
{
	int idx = 0;

	while (idx < ARRAY_SIZE(settings) &&
			(settings[idx].speed != speed ||
			settings[idx].duplex != duplex))
		idx++;

	return idx < MAX_NUM_SETTINGS ? idx : MAX_NUM_SETTINGS - 1;
}

/**
 * phy_find_valid - find a PHY setting that matches the requested features mask
 * @idx: The first index in settings[] to search
 * @features: A mask of the valid settings
 *
 * Description: Returns the index of the first valid setting less
 *   than or equal to the one pointed to by idx, as determined by
 *   the mask in features.  Returns the index of the last setting
 *   if nothing else matches.
 */
static inline int phy_find_valid(int idx, u32 features)
{
	while (idx < MAX_NUM_SETTINGS && !(settings[idx].setting & features))
		idx++;

	return idx < MAX_NUM_SETTINGS ? idx : MAX_NUM_SETTINGS - 1;
}

/**
 * phy_sanitize_settings - make sure the PHY is set to supported speed and duplex
 * @phydev: the target phy_device struct
 *
 * Description: Make sure the PHY is set to supported speeds and
 *   duplexes.  Drop down by one in this order:  1000/FULL,
 *   1000/HALF, 100/FULL, 100/HALF, 10/FULL, 10/HALF.
 */
void phy_sanitize_settings(struct phy_device *phydev)
{
	u32 features = phydev->supported;
	int idx;

	/* Sanitize settings based on PHY capabilities */
	if ((features & SUPPORTED_Autoneg) == 0)
		phydev->autoneg = AUTONEG_DISABLE;

	idx = phy_find_valid(phy_find_setting(phydev->speed, phydev->duplex),
			features);

	phydev->speed = settings[idx].speed;
	phydev->duplex = settings[idx].duplex;
}
EXPORT_SYMBOL(phy_sanitize_settings);

/**
 * phy_ethtool_sset - generic ethtool sset function, handles all the details
 * @phydev: target phy_device struct
 * @cmd: ethtool_cmd
 *
 * A few notes about parameter checking:
 * - We don't set port or transceiver, so we don't care what they
 *   were set to.
 * - phy_start_aneg() will make sure forced settings are sane, and
 *   choose the next best ones from the ones selected, so we don't
 *   care if ethtool tries to give us bad values.
 */
int phy_ethtool_sset(struct phy_device *phydev, struct ethtool_cmd *cmd)
{
	if (cmd->phy_address != phydev->addr)
		return -EINVAL;

	/* We make sure that we don't pass unsupported
	 * values in to the PHY */
	cmd->advertising &= phydev->supported;

	/* Verify the settings we care about. */
	if (cmd->autoneg != AUTONEG_ENABLE && cmd->autoneg != AUTONEG_DISABLE)
		return -EINVAL;

	if (cmd->autoneg == AUTONEG_ENABLE && cmd->advertising == 0)
		return -EINVAL;

	if (cmd->autoneg == AUTONEG_DISABLE
			&& ((cmd->speed != SPEED_1000
					&& cmd->speed != SPEED_100
					&& cmd->speed != SPEED_10)
				|| (cmd->duplex != DUPLEX_HALF
					&& cmd->duplex != DUPLEX_FULL)))
		return -EINVAL;

	phydev->autoneg = cmd->autoneg;

	phydev->speed = cmd->speed;

	phydev->advertising = cmd->advertising;

	if (AUTONEG_ENABLE == cmd->autoneg)
		phydev->advertising |= ADVERTISED_Autoneg;
	else
		phydev->advertising &= ~ADVERTISED_Autoneg;

	phydev->duplex = cmd->duplex;

	/* Restart the PHY */
	phy_start_aneg(phydev);

	return 0;
}
EXPORT_SYMBOL(phy_ethtool_sset);

int phy_ethtool_gset(struct phy_device *phydev, struct ethtool_cmd *cmd)
{
	cmd->supported = phydev->supported;

	cmd->advertising = phydev->advertising;

	cmd->speed = phydev->speed;
	cmd->duplex = phydev->duplex;
	cmd->port = PORT_MII;
	cmd->phy_address = phydev->addr;
	cmd->transceiver = XCVR_EXTERNAL;
	cmd->autoneg = phydev->autoneg;

	return 0;
}
EXPORT_SYMBOL(phy_ethtool_gset);

/**
 * phy_mii_ioctl - generic PHY MII ioctl interface
 * @phydev: the phy_device struct
 * @mii_data: MII ioctl data
 * @cmd: ioctl cmd to execute
 *
 * Note that this function is currently incompatible with the
 * PHYCONTROL layer.  It changes registers without regard to
 * current state.  Use at own risk.
 */
int phy_mii_ioctl(struct phy_device *phydev,
		struct mii_ioctl_data *mii_data, int cmd)
{
	u16 val = mii_data->val_in;

	switch (cmd) {
	case SIOCGMIIPHY:
		mii_data->phy_id = phydev->addr;
		break;
	case SIOCGMIIREG:
		mii_data->val_out = phy_read(phydev, mii_data->reg_num);
		break;

	case SIOCSMIIREG:
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

		if (mii_data->phy_id == phydev->addr) {
			switch(mii_data->reg_num) {
			case MII_BMCR:
				if ((val & (BMCR_RESET|BMCR_ANENABLE)) == 0)
					phydev->autoneg = AUTONEG_DISABLE;
				else
					phydev->autoneg = AUTONEG_ENABLE;
				if ((!phydev->autoneg) && (val & BMCR_FULLDPLX))
					phydev->duplex = DUPLEX_FULL;
				else
					phydev->duplex = DUPLEX_HALF;
				if ((!phydev->autoneg) &&
						(val & BMCR_SPEED1000))
					phydev->speed = SPEED_1000;
				else if ((!phydev->autoneg) &&
						(val & BMCR_SPEED100))
					phydev->speed = SPEED_100;
				break;
			case MII_ADVERTISE:
				phydev->advertising = val;
				break;
			default:
				/* do nothing */
				break;
			}
		}

		phy_write(phydev, mii_data->reg_num, val);
		
		if (mii_data->reg_num == MII_BMCR 
				&& val & BMCR_RESET
				&& phydev->drv->config_init)
			phydev->drv->config_init(phydev);
		break;
	}

	return 0;
}
EXPORT_SYMBOL(phy_mii_ioctl);

/**
 * phy_start_aneg - start auto-negotiation for this PHY device
 * @phydev: the phy_device struct
 *
 * Description: Sanitizes the settings (if we're not autonegotiating
 *   them), and then calls the driver's config_aneg function.
 *   If the PHYCONTROL Layer is operating, we change the state to
 *   reflect the beginning of Auto-negotiation or forcing.
 */
int phy_start_aneg(struct phy_device *phydev)
{
	int err;

	spin_lock_bh(&phydev->lock);

	if (AUTONEG_DISABLE == phydev->autoneg)
		phy_sanitize_settings(phydev);

	err = phydev->drv->config_aneg(phydev);

	if (err < 0)
		goto out_unlock;

	if (phydev->state != PHY_HALTED) {
		if (AUTONEG_ENABLE == phydev->autoneg) {
			phydev->state = PHY_AN;
			phydev->link_timeout = PHY_AN_TIMEOUT;
		} else {
			phydev->state = PHY_FORCING;
			phydev->link_timeout = PHY_FORCE_TIMEOUT;
		}
	}

out_unlock:
	spin_unlock_bh(&phydev->lock);
	return err;
}
EXPORT_SYMBOL(phy_start_aneg);


static void phy_change(struct work_struct *work);
static void phy_timer(unsigned long data);

/**
 * phy_start_machine - start PHY state machine tracking
 * @phydev: the phy_device struct
 * @handler: callback function for state change notifications
 *
 * Description: The PHY infrastructure can run a state machine
 *   which tracks whether the PHY is starting up, negotiating,
 *   etc.  This function starts the timer which tracks the state
 *   of the PHY.  If you want to be notified when the state changes,
 *   pass in the callback @handler, otherwise, pass NULL.  If you
 *   want to maintain your own state machine, do not call this
 *   function.
 */
void phy_start_machine(struct phy_device *phydev,
		void (*handler)(struct net_device *))
{
	phydev->adjust_state = handler;

	init_timer(&phydev->phy_timer);
	phydev->phy_timer.function = &phy_timer;
	phydev->phy_timer.data = (unsigned long) phydev;
	mod_timer(&phydev->phy_timer, jiffies + HZ);
}

/**
 * phy_stop_machine - stop the PHY state machine tracking
 * @phydev: target phy_device struct
 *
 * Description: Stops the state machine timer, sets the state to UP
 *   (unless it wasn't up yet). This function must be called BEFORE
 *   phy_detach.
 */
void phy_stop_machine(struct phy_device *phydev)
{
	del_timer_sync(&phydev->phy_timer);

	spin_lock_bh(&phydev->lock);
	if (phydev->state > PHY_UP)
		phydev->state = PHY_UP;
	spin_unlock_bh(&phydev->lock);

	phydev->adjust_state = NULL;
}

/**
 * phy_force_reduction - reduce PHY speed/duplex settings by one step
 * @phydev: target phy_device struct
 *
 * Description: Reduces the speed/duplex settings by one notch,
 *   in this order--
 *   1000/FULL, 1000/HALF, 100/FULL, 100/HALF, 10/FULL, 10/HALF.
 *   The function bottoms out at 10/HALF.
 */
static void phy_force_reduction(struct phy_device *phydev)
{
	int idx;

	idx = phy_find_setting(phydev->speed, phydev->duplex);
	
	idx++;

	idx = phy_find_valid(idx, phydev->supported);

	phydev->speed = settings[idx].speed;
	phydev->duplex = settings[idx].duplex;

	pr_info("Trying %d/%s\n", phydev->speed,
			DUPLEX_FULL == phydev->duplex ?
			"FULL" : "HALF");
}


/**
 * phy_error - enter HALTED state for this PHY device
 * @phydev: target phy_device struct
 *
 * Moves the PHY to the HALTED state in response to a read
 * or write error, and tells the controller the link is down.
 * Must not be called from interrupt context, or while the
 * phydev->lock is held.
 */
void phy_error(struct phy_device *phydev)
{
	spin_lock_bh(&phydev->lock);
	phydev->state = PHY_HALTED;
	spin_unlock_bh(&phydev->lock);
}

/**
 * phy_interrupt - PHY interrupt handler
 * @irq: interrupt line
 * @phy_dat: phy_device pointer
 *
 * Description: When a PHY interrupt occurs, the handler disables
 * interrupts, and schedules a work task to clear the interrupt.
 */
static irqreturn_t phy_interrupt(int irq, void *phy_dat)
{
	struct phy_device *phydev = phy_dat;

	if (PHY_HALTED == phydev->state)
		return IRQ_NONE;		/* It can't be ours.  */

	/* The MDIO bus is not allowed to be written in interrupt
	 * context, so we need to disable the irq here.  A work
	 * queue will write the PHY to disable and clear the
	 * interrupt, and then reenable the irq line. */
	disable_irq_nosync(irq);
	atomic_inc(&phydev->irq_disable);

	schedule_work(&phydev->phy_queue);

	return IRQ_HANDLED;
}

/**
 * phy_enable_interrupts - Enable the interrupts from the PHY side
 * @phydev: target phy_device struct
 */
int phy_enable_interrupts(struct phy_device *phydev)
{
	int err;

	err = phy_clear_interrupt(phydev);

	if (err < 0)
		return err;

	err = phy_config_interrupt(phydev, PHY_INTERRUPT_ENABLED);

	return err;
}
EXPORT_SYMBOL(phy_enable_interrupts);

/**
 * phy_disable_interrupts - Disable the PHY interrupts from the PHY side
 * @phydev: target phy_device struct
 */
int phy_disable_interrupts(struct phy_device *phydev)
{
	int err;

	/* Disable PHY interrupts */
	err = phy_config_interrupt(phydev, PHY_INTERRUPT_DISABLED);

	if (err)
		goto phy_err;

	/* Clear the interrupt */
	err = phy_clear_interrupt(phydev);

	if (err)
		goto phy_err;

	return 0;

phy_err:
	phy_error(phydev);

	return err;
}
EXPORT_SYMBOL(phy_disable_interrupts);

/**
 * phy_start_interrupts - request and enable interrupts for a PHY device
 * @phydev: target phy_device struct
 *
 * Description: Request the interrupt for the given PHY.
 *   If this fails, then we set irq to PHY_POLL.
 *   Otherwise, we enable the interrupts in the PHY.
 *   This should only be called with a valid IRQ number.
 *   Returns 0 on success or < 0 on error.
 */
int phy_start_interrupts(struct phy_device *phydev)
{
	int err = 0;

	INIT_WORK(&phydev->phy_queue, phy_change);

	atomic_set(&phydev->irq_disable, 0);
	if (request_irq(phydev->irq, phy_interrupt,
				IRQF_SHARED,
				"phy_interrupt",
				phydev) < 0) {
		printk(KERN_WARNING "%s: Can't get IRQ %d (PHY)\n",
				phydev->bus->name,
				phydev->irq);
		phydev->irq = PHY_POLL;
		return 0;
	}

	err = phy_enable_interrupts(phydev);

	return err;
}
EXPORT_SYMBOL(phy_start_interrupts);

/**
 * phy_stop_interrupts - disable interrupts from a PHY device
 * @phydev: target phy_device struct
 */
int phy_stop_interrupts(struct phy_device *phydev)
{
	int err;

	err = phy_disable_interrupts(phydev);

	if (err)
		phy_error(phydev);

	free_irq(phydev->irq, phydev);

	/*
	 * Cannot call flush_scheduled_work() here as desired because
	 * of rtnl_lock(), but we do not really care about what would
	 * be done, except from enable_irq(), so cancel any work
	 * possibly pending and take care of the matter below.
	 */
	cancel_work_sync(&phydev->phy_queue);
	/*
	 * If work indeed has been cancelled, disable_irq() will have
	 * been left unbalanced from phy_interrupt() and enable_irq()
	 * has to be called so that other devices on the line work.
	 */
	while (atomic_dec_return(&phydev->irq_disable) >= 0)
		enable_irq(phydev->irq);

	return err;
}
EXPORT_SYMBOL(phy_stop_interrupts);


/**
 * phy_change - Scheduled by the phy_interrupt/timer to handle PHY changes
 * @work: work_struct that describes the work to be done
 */
static void phy_change(struct work_struct *work)
{
	int err;
	struct phy_device *phydev =
		container_of(work, struct phy_device, phy_queue);

	err = phy_disable_interrupts(phydev);

	if (err)
		goto phy_err;

	spin_lock_bh(&phydev->lock);
	if ((PHY_RUNNING == phydev->state) || (PHY_NOLINK == phydev->state))
		phydev->state = PHY_CHANGELINK;
	spin_unlock_bh(&phydev->lock);

	atomic_dec(&phydev->irq_disable);
	enable_irq(phydev->irq);

	/* Reenable interrupts */
	if (PHY_HALTED != phydev->state)
		err = phy_config_interrupt(phydev, PHY_INTERRUPT_ENABLED);

	if (err)
		goto irq_enable_err;

	return;

irq_enable_err:
	disable_irq(phydev->irq);
	atomic_inc(&phydev->irq_disable);
phy_err:
	phy_error(phydev);
}

/**
 * phy_stop - Bring down the PHY link, and stop checking the status
 * @phydev: target phy_device struct
 */
void phy_stop(struct phy_device *phydev)
{
	spin_lock_bh(&phydev->lock);

	if (PHY_HALTED == phydev->state)
		goto out_unlock;

	if (phydev->irq != PHY_POLL) {
		/* Disable PHY Interrupts */
		phy_config_interrupt(phydev, PHY_INTERRUPT_DISABLED);

		/* Clear any pending interrupts */
		phy_clear_interrupt(phydev);
	}

	phydev->state = PHY_HALTED;

out_unlock:
	spin_unlock_bh(&phydev->lock);

	/*
	 * Cannot call flush_scheduled_work() here as desired because
	 * of rtnl_lock(), but PHY_HALTED shall guarantee phy_change()
	 * will not reenable interrupts.
	 */
}


/**
 * phy_start - start or restart a PHY device
 * @phydev: target phy_device struct
 *
 * Description: Indicates the attached device's readiness to
 *   handle PHY-related work.  Used during startup to start the
 *   PHY, and after a call to phy_stop() to resume operation.
 *   Also used to indicate the MDIO bus has cleared an error
 *   condition.
 */
void phy_start(struct phy_device *phydev)
{
	spin_lock_bh(&phydev->lock);

	switch (phydev->state) {
		case PHY_STARTING:
			phydev->state = PHY_PENDING;
			break;
		case PHY_READY:
			phydev->state = PHY_UP;
			break;
		case PHY_HALTED:
			phydev->state = PHY_RESUMING;
		default:
			break;
	}
	spin_unlock_bh(&phydev->lock);
}
EXPORT_SYMBOL(phy_stop);
EXPORT_SYMBOL(phy_start);

/* PHY timer which handles the state machine */
static void phy_timer(unsigned long data)
{
	struct phy_device *phydev = (struct phy_device *)data;
	int needs_aneg = 0;
	int err = 0;

	spin_lock_bh(&phydev->lock);

	if (phydev->adjust_state)
		phydev->adjust_state(phydev->attached_dev);

	switch(phydev->state) {
		case PHY_DOWN:
		case PHY_STARTING:
		case PHY_READY:
		case PHY_PENDING:
			break;
		case PHY_UP:
			needs_aneg = 1;

			phydev->link_timeout = PHY_AN_TIMEOUT;

			break;
		case PHY_AN:
			err = phy_read_status(phydev);

			if (err < 0)
				break;

			/* If the link is down, give up on
			 * negotiation for now */
			if (!phydev->link) {
				phydev->state = PHY_NOLINK;
				netif_carrier_off(phydev->attached_dev);
				phydev->adjust_link(phydev->attached_dev);
				break;
			}

			/* Check if negotiation is done.  Break
			 * if there's an error */
			err = phy_aneg_done(phydev);
			if (err < 0)
				break;

			/* If AN is done, we're running */
			if (err > 0) {
				phydev->state = PHY_RUNNING;
				netif_carrier_on(phydev->attached_dev);
				phydev->adjust_link(phydev->attached_dev);

			} else if (0 == phydev->link_timeout--) {
				int idx;

				needs_aneg = 1;
				/* If we have the magic_aneg bit,
				 * we try again */
				if (phydev->drv->flags & PHY_HAS_MAGICANEG)
					break;

				/* The timer expired, and we still
				 * don't have a setting, so we try
				 * forcing it until we find one that
				 * works, starting from the fastest speed,
				 * and working our way down */
				idx = phy_find_valid(0, phydev->supported);

				phydev->speed = settings[idx].speed;
				phydev->duplex = settings[idx].duplex;

				phydev->autoneg = AUTONEG_DISABLE;

				pr_info("Trying %d/%s\n", phydev->speed,
						DUPLEX_FULL ==
						phydev->duplex ?
						"FULL" : "HALF");
			}
			break;
		case PHY_NOLINK:
			err = phy_read_status(phydev);

			if (err)
				break;

			if (phydev->link) {
				phydev->state = PHY_RUNNING;
				netif_carrier_on(phydev->attached_dev);
				phydev->adjust_link(phydev->attached_dev);
			}
			break;
		case PHY_FORCING:
			err = genphy_update_link(phydev);

			if (err)
				break;

			if (phydev->link) {
				phydev->state = PHY_RUNNING;
				netif_carrier_on(phydev->attached_dev);
			} else {
				if (0 == phydev->link_timeout--) {
					phy_force_reduction(phydev);
					needs_aneg = 1;
				}
			}

			phydev->adjust_link(phydev->attached_dev);
			break;
		case PHY_RUNNING:
			/* Only register a CHANGE if we are
			 * polling */
			if (PHY_POLL == phydev->irq)
				phydev->state = PHY_CHANGELINK;
			break;
		case PHY_CHANGELINK:
			err = phy_read_status(phydev);

			if (err)
				break;

			if (phydev->link) {
				phydev->state = PHY_RUNNING;
				netif_carrier_on(phydev->attached_dev);
			} else {
				phydev->state = PHY_NOLINK;
				netif_carrier_off(phydev->attached_dev);
			}

			phydev->adjust_link(phydev->attached_dev);

			if (PHY_POLL != phydev->irq)
				err = phy_config_interrupt(phydev,
						PHY_INTERRUPT_ENABLED);
			break;
		case PHY_HALTED:
			if (phydev->link) {
				phydev->link = 0;
				netif_carrier_off(phydev->attached_dev);
				phydev->adjust_link(phydev->attached_dev);
			}
			break;
		case PHY_RESUMING:

			err = phy_clear_interrupt(phydev);

			if (err)
				break;

			err = phy_config_interrupt(phydev,
					PHY_INTERRUPT_ENABLED);

			if (err)
				break;

			if (AUTONEG_ENABLE == phydev->autoneg) {
				err = phy_aneg_done(phydev);
				if (err < 0)
					break;

				/* err > 0 if AN is done.
				 * Otherwise, it's 0, and we're
				 * still waiting for AN */
				if (err > 0) {
					phydev->state = PHY_RUNNING;
				} else {
					phydev->state = PHY_AN;
					phydev->link_timeout = PHY_AN_TIMEOUT;
				}
			} else
				phydev->state = PHY_RUNNING;
			break;
	}

	spin_unlock_bh(&phydev->lock);

	if (needs_aneg)
		err = phy_start_aneg(phydev);

	if (err < 0)
		phy_error(phydev);

	mod_timer(&phydev->phy_timer, jiffies + PHY_STATE_TIME * HZ);
}