summaryrefslogtreecommitdiffstats
path: root/drivers/soundwire/bus.c
blob: 5d7226c251e69b33ddec69c66de9657d10043fa7 (plain)
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
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
// Copyright(c) 2015-17 Intel Corporation.

#include <linux/acpi.h>
#include <linux/mod_devicetable.h>
#include <linux/pm_runtime.h>
#include <linux/soundwire/sdw_registers.h>
#include <linux/soundwire/sdw.h>
#include "bus.h"

/**
 * sdw_add_bus_master() - add a bus Master instance
 * @bus: bus instance
 *
 * Initializes the bus instance, read properties and create child
 * devices.
 */
int sdw_add_bus_master(struct sdw_bus *bus)
{
	int ret;

	if (!bus->dev) {
		pr_err("SoundWire bus has no device");
		return -ENODEV;
	}

	if (!bus->ops) {
		dev_err(bus->dev, "SoundWire Bus ops are not set");
		return -EINVAL;
	}

	mutex_init(&bus->msg_lock);
	mutex_init(&bus->bus_lock);
	INIT_LIST_HEAD(&bus->slaves);

	if (bus->ops->read_prop) {
		ret = bus->ops->read_prop(bus);
		if (ret < 0) {
			dev_err(bus->dev, "Bus read properties failed:%d", ret);
			return ret;
		}
	}

	/*
	 * Device numbers in SoundWire are 0 thru 15. Enumeration device
	 * number (0), Broadcast device number (15), Group numbers (12 and
	 * 13) and Master device number (14) are not used for assignment so
	 * mask these and other higher bits.
	 */

	/* Set higher order bits */
	*bus->assigned = ~GENMASK(SDW_BROADCAST_DEV_NUM, SDW_ENUM_DEV_NUM);

	/* Set enumuration device number and broadcast device number */
	set_bit(SDW_ENUM_DEV_NUM, bus->assigned);
	set_bit(SDW_BROADCAST_DEV_NUM, bus->assigned);

	/* Set group device numbers and master device number */
	set_bit(SDW_GROUP12_DEV_NUM, bus->assigned);
	set_bit(SDW_GROUP13_DEV_NUM, bus->assigned);
	set_bit(SDW_MASTER_DEV_NUM, bus->assigned);

	/*
	 * SDW is an enumerable bus, but devices can be powered off. So,
	 * they won't be able to report as present.
	 *
	 * Create Slave devices based on Slaves described in
	 * the respective firmware (ACPI/DT)
	 */
	if (IS_ENABLED(CONFIG_ACPI) && ACPI_HANDLE(bus->dev))
		ret = sdw_acpi_find_slaves(bus);
	else
		ret = -ENOTSUPP; /* No ACPI/DT so error out */

	if (ret) {
		dev_err(bus->dev, "Finding slaves failed:%d\n", ret);
		return ret;
	}

	return 0;
}
EXPORT_SYMBOL(sdw_add_bus_master);

static int sdw_delete_slave(struct device *dev, void *data)
{
	struct sdw_slave *slave = dev_to_sdw_dev(dev);
	struct sdw_bus *bus = slave->bus;

	mutex_lock(&bus->bus_lock);

	if (slave->dev_num) /* clear dev_num if assigned */
		clear_bit(slave->dev_num, bus->assigned);

	list_del_init(&slave->node);
	mutex_unlock(&bus->bus_lock);

	device_unregister(dev);
	return 0;
}

/**
 * sdw_delete_bus_master() - delete the bus master instance
 * @bus: bus to be deleted
 *
 * Remove the instance, delete the child devices.
 */
void sdw_delete_bus_master(struct sdw_bus *bus)
{
	device_for_each_child(bus->dev, NULL, sdw_delete_slave);
}
EXPORT_SYMBOL(sdw_delete_bus_master);

/*
 * SDW IO Calls
 */

static inline int find_response_code(enum sdw_command_response resp)
{
	switch (resp) {
	case SDW_CMD_OK:
		return 0;

	case SDW_CMD_IGNORED:
		return -ENODATA;

	case SDW_CMD_TIMEOUT:
		return -ETIMEDOUT;

	default:
		return -EIO;
	}
}

static inline int do_transfer(struct sdw_bus *bus, struct sdw_msg *msg)
{
	int retry = bus->prop.err_threshold;
	enum sdw_command_response resp;
	int ret = 0, i;

	for (i = 0; i <= retry; i++) {
		resp = bus->ops->xfer_msg(bus, msg);
		ret = find_response_code(resp);

		/* if cmd is ok or ignored return */
		if (ret == 0 || ret == -ENODATA)
			return ret;
	}

	return ret;
}

static inline int do_transfer_defer(struct sdw_bus *bus,
			struct sdw_msg *msg, struct sdw_defer *defer)
{
	int retry = bus->prop.err_threshold;
	enum sdw_command_response resp;
	int ret = 0, i;

	defer->msg = msg;
	defer->length = msg->len;

	for (i = 0; i <= retry; i++) {
		resp = bus->ops->xfer_msg_defer(bus, msg, defer);
		ret = find_response_code(resp);
		/* if cmd is ok or ignored return */
		if (ret == 0 || ret == -ENODATA)
			return ret;
	}

	return ret;
}

static int sdw_reset_page(struct sdw_bus *bus, u16 dev_num)
{
	int retry = bus->prop.err_threshold;
	enum sdw_command_response resp;
	int ret = 0, i;

	for (i = 0; i <= retry; i++) {
		resp = bus->ops->reset_page_addr(bus, dev_num);
		ret = find_response_code(resp);
		/* if cmd is ok or ignored return */
		if (ret == 0 || ret == -ENODATA)
			return ret;
	}

	return ret;
}

/**
 * sdw_transfer() - Synchronous transfer message to a SDW Slave device
 * @bus: SDW bus
 * @msg: SDW message to be xfered
 */
int sdw_transfer(struct sdw_bus *bus, struct sdw_msg *msg)
{
	int ret;

	mutex_lock(&bus->msg_lock);

	ret = do_transfer(bus, msg);
	if (ret != 0 && ret != -ENODATA)
		dev_err(bus->dev, "trf on Slave %d failed:%d\n",
				msg->dev_num, ret);

	if (msg->page)
		sdw_reset_page(bus, msg->dev_num);

	mutex_unlock(&bus->msg_lock);

	return ret;
}

/**
 * sdw_transfer_defer() - Asynchronously transfer message to a SDW Slave device
 * @bus: SDW bus
 * @msg: SDW message to be xfered
 * @defer: Defer block for signal completion
 *
 * Caller needs to hold the msg_lock lock while calling this
 */
int sdw_transfer_defer(struct sdw_bus *bus, struct sdw_msg *msg,
				struct sdw_defer *defer)
{
	int ret;

	if (!bus->ops->xfer_msg_defer)
		return -ENOTSUPP;

	ret = do_transfer_defer(bus, msg, defer);
	if (ret != 0 && ret != -ENODATA)
		dev_err(bus->dev, "Defer trf on Slave %d failed:%d\n",
				msg->dev_num, ret);

	if (msg->page)
		sdw_reset_page(bus, msg->dev_num);

	return ret;
}


int sdw_fill_msg(struct sdw_msg *msg, struct sdw_slave *slave,
		u32 addr, size_t count, u16 dev_num, u8 flags, u8 *buf)
{
	memset(msg, 0, sizeof(*msg));
	msg->addr = addr; /* addr is 16 bit and truncated here */
	msg->len = count;
	msg->dev_num = dev_num;
	msg->flags = flags;
	msg->buf = buf;
	msg->ssp_sync = false;
	msg->page = false;

	if (addr < SDW_REG_NO_PAGE) { /* no paging area */
		return 0;
	} else if (addr >= SDW_REG_MAX) { /* illegal addr */
		pr_err("SDW: Invalid address %x passed\n", addr);
		return -EINVAL;
	}

	if (addr < SDW_REG_OPTIONAL_PAGE) { /* 32k but no page */
		if (slave && !slave->prop.paging_support)
			return 0;
		/* no need for else as that will fall thru to paging */
	}

	/* paging mandatory */
	if (dev_num == SDW_ENUM_DEV_NUM || dev_num == SDW_BROADCAST_DEV_NUM) {
		pr_err("SDW: Invalid device for paging :%d\n", dev_num);
		return -EINVAL;
	}

	if (!slave) {
		pr_err("SDW: No slave for paging addr\n");
		return -EINVAL;
	} else if (!slave->prop.paging_support) {
		dev_err(&slave->dev,
			"address %x needs paging but no support", addr);
		return -EINVAL;
	}

	msg->addr_page1 = (addr >> SDW_REG_SHIFT(SDW_SCP_ADDRPAGE1_MASK));
	msg->addr_page2 = (addr >> SDW_REG_SHIFT(SDW_SCP_ADDRPAGE2_MASK));
	msg->addr |= BIT(15);
	msg->page = true;

	return 0;
}

/**
 * sdw_nread() - Read "n" contiguous SDW Slave registers
 * @slave: SDW Slave
 * @addr: Register address
 * @count: length
 * @val: Buffer for values to be read
 */
int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
{
	struct sdw_msg msg;
	int ret;

	ret = sdw_fill_msg(&msg, slave, addr, count,
			slave->dev_num, SDW_MSG_FLAG_READ, val);
	if (ret < 0)
		return ret;

	ret = pm_runtime_get_sync(slave->bus->dev);
	if (ret < 0)
		return ret;

	ret = sdw_transfer(slave->bus, &msg);
	pm_runtime_put(slave->bus->dev);

	return ret;
}
EXPORT_SYMBOL(sdw_nread);

/**
 * sdw_nwrite() - Write "n" contiguous SDW Slave registers
 * @slave: SDW Slave
 * @addr: Register address
 * @count: length
 * @val: Buffer for values to be read
 */
int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
{
	struct sdw_msg msg;
	int ret;

	ret = sdw_fill_msg(&msg, slave, addr, count,
			slave->dev_num, SDW_MSG_FLAG_WRITE, val);
	if (ret < 0)
		return ret;

	ret = pm_runtime_get_sync(slave->bus->dev);
	if (ret < 0)
		return ret;

	ret = sdw_transfer(slave->bus, &msg);
	pm_runtime_put(slave->bus->dev);

	return ret;
}
EXPORT_SYMBOL(sdw_nwrite);

/**
 * sdw_read() - Read a SDW Slave register
 * @slave: SDW Slave
 * @addr: Register address
 */
int sdw_read(struct sdw_slave *slave, u32 addr)
{
	u8 buf;
	int ret;

	ret = sdw_nread(slave, addr, 1, &buf);
	if (ret < 0)
		return ret;
	else
		return buf;
}
EXPORT_SYMBOL(sdw_read);

/**
 * sdw_write() - Write a SDW Slave register
 * @slave: SDW Slave
 * @addr: Register address
 * @value: Register value
 */
int sdw_write(struct sdw_slave *slave, u32 addr, u8 value)
{
	return sdw_nwrite(slave, addr, 1, &value);

}
EXPORT_SYMBOL(sdw_write);

/*
 * SDW alert handling
 */

/* called with bus_lock held */
static struct sdw_slave *sdw_get_slave(struct sdw_bus *bus, int i)
{
	struct sdw_slave *slave = NULL;

	list_for_each_entry(slave, &bus->slaves, node) {
		if (slave->dev_num == i)
			return slave;
	}

	return NULL;
}

static int sdw_compare_devid(struct sdw_slave *slave, struct sdw_slave_id id)
{

	if ((slave->id.unique_id != id.unique_id) ||
	    (slave->id.mfg_id != id.mfg_id) ||
	    (slave->id.part_id != id.part_id) ||
	    (slave->id.class_id != id.class_id))
		return -ENODEV;

	return 0;
}

/* called with bus_lock held */
static int sdw_get_device_num(struct sdw_slave *slave)
{
	int bit;

	bit = find_first_zero_bit(slave->bus->assigned, SDW_MAX_DEVICES);
	if (bit == SDW_MAX_DEVICES) {
		bit = -ENODEV;
		goto err;
	}

	/*
	 * Do not update dev_num in Slave data structure here,
	 * Update once program dev_num is successful
	 */
	set_bit(bit, slave->bus->assigned);

err:
	return bit;
}

static int sdw_assign_device_num(struct sdw_slave *slave)
{
	int ret, dev_num;

	/* check first if device number is assigned, if so reuse that */
	if (!slave->dev_num) {
		mutex_lock(&slave->bus->bus_lock);
		dev_num = sdw_get_device_num(slave);
		mutex_unlock(&slave->bus->bus_lock);
		if (dev_num < 0) {
			dev_err(slave->bus->dev, "Get dev_num failed: %d",
								dev_num);
			return dev_num;
		}
	} else {
		dev_info(slave->bus->dev,
				"Slave already registered dev_num:%d",
				slave->dev_num);

		/* Clear the slave->dev_num to transfer message on device 0 */
		dev_num = slave->dev_num;
		slave->dev_num = 0;

	}

	ret = sdw_write(slave, SDW_SCP_DEVNUMBER, dev_num);
	if (ret < 0) {
		dev_err(&slave->dev, "Program device_num failed: %d", ret);
		return ret;
	}

	/* After xfer of msg, restore dev_num */
	slave->dev_num = dev_num;

	return 0;
}

void sdw_extract_slave_id(struct sdw_bus *bus,
			u64 addr, struct sdw_slave_id *id)
{
	dev_dbg(bus->dev, "SDW Slave Addr: %llx", addr);

	/*
	 * Spec definition
	 *   Register		Bit	Contents
	 *   DevId_0 [7:4]	47:44	sdw_version
	 *   DevId_0 [3:0]	43:40	unique_id
	 *   DevId_1		39:32	mfg_id [15:8]
	 *   DevId_2		31:24	mfg_id [7:0]
	 *   DevId_3		23:16	part_id [15:8]
	 *   DevId_4		15:08	part_id [7:0]
	 *   DevId_5		07:00	class_id
	 */
	id->sdw_version = (addr >> 44) & GENMASK(3, 0);
	id->unique_id = (addr >> 40) & GENMASK(3, 0);
	id->mfg_id = (addr >> 24) & GENMASK(15, 0);
	id->part_id = (addr >> 8) & GENMASK(15, 0);
	id->class_id = addr & GENMASK(7, 0);

	dev_dbg(bus->dev,
		"SDW Slave class_id %x, part_id %x, mfg_id %x, unique_id %x, version %x",
				id->class_id, id->part_id, id->mfg_id,
				id->unique_id, id->sdw_version);

}

static int sdw_program_device_num(struct sdw_bus *bus)
{
	u8 buf[SDW_NUM_DEV_ID_REGISTERS] = {0};
	struct sdw_slave *slave, *_s;
	struct sdw_slave_id id;
	struct sdw_msg msg;
	bool found = false;
	int count = 0, ret;
	u64 addr;

	/* No Slave, so use raw xfer api */
	ret = sdw_fill_msg(&msg, NULL, SDW_SCP_DEVID_0,
			SDW_NUM_DEV_ID_REGISTERS, 0, SDW_MSG_FLAG_READ, buf);
	if (ret < 0)
		return ret;

	do {
		ret = sdw_transfer(bus, &msg);
		if (ret == -ENODATA) { /* end of device id reads */
			ret = 0;
			break;
		}
		if (ret < 0) {
			dev_err(bus->dev, "DEVID read fail:%d\n", ret);
			break;
		}

		/*
		 * Construct the addr and extract. Cast the higher shift
		 * bits to avoid truncation due to size limit.
		 */
		addr = buf[5] | (buf[4] << 8) | (buf[3] << 16) |
			((u64)buf[2] << 24) | ((u64)buf[1] << 32) |
			((u64)buf[0] << 40);

		sdw_extract_slave_id(bus, addr, &id);

		/* Now compare with entries */
		list_for_each_entry_safe(slave, _s, &bus->slaves, node) {
			if (sdw_compare_devid(slave, id) == 0) {
				found = true;

				/*
				 * Assign a new dev_num to this Slave and
				 * not mark it present. It will be marked
				 * present after it reports ATTACHED on new
				 * dev_num
				 */
				ret = sdw_assign_device_num(slave);
				if (ret) {
					dev_err(slave->bus->dev,
						"Assign dev_num failed:%d",
						ret);
					return ret;
				}

				break;
			}
		}

		if (found == false) {
			/* TODO: Park this device in Group 13 */
			dev_err(bus->dev, "Slave Entry not found");
		}

		count++;

		/*
		 * Check till error out or retry (count) exhausts.
		 * Device can drop off and rejoin during enumeration
		 * so count till twice the bound.
		 */

	} while (ret == 0 && count < (SDW_MAX_DEVICES * 2));

	return ret;
}

static void sdw_modify_slave_status(struct sdw_slave *slave,
				enum sdw_slave_status status)
{
	mutex_lock(&slave->bus->bus_lock);
	slave->status = status;
	mutex_unlock(&slave->bus->bus_lock);
}

static int sdw_initialize_slave(struct sdw_slave *slave)
{
	struct sdw_slave_prop *prop = &slave->prop;
	int ret;
	u8 val;

	/*
	 * Set bus clash, parity and SCP implementation
	 * defined interrupt mask
	 * TODO: Read implementation defined interrupt mask
	 * from Slave property
	 */
	val = SDW_SCP_INT1_IMPL_DEF | SDW_SCP_INT1_BUS_CLASH |
					SDW_SCP_INT1_PARITY;

	/* Enable SCP interrupts */
	ret = sdw_update(slave, SDW_SCP_INTMASK1, val, val);
	if (ret < 0) {
		dev_err(slave->bus->dev,
				"SDW_SCP_INTMASK1 write failed:%d", ret);
		return ret;
	}

	/* No need to continue if DP0 is not present */
	if (!slave->prop.dp0_prop)
		return 0;

	/* Enable DP0 interrupts */
	val = prop->dp0_prop->device_interrupts;
	val |= SDW_DP0_INT_PORT_READY | SDW_DP0_INT_BRA_FAILURE;

	ret = sdw_update(slave, SDW_DP0_INTMASK, val, val);
	if (ret < 0) {
		dev_err(slave->bus->dev,
				"SDW_DP0_INTMASK read failed:%d", ret);
		return val;
	}

	return 0;
}

static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
{
	u8 clear = 0, impl_int_mask;
	int status, status2, ret, count = 0;

	status = sdw_read(slave, SDW_DP0_INT);
	if (status < 0) {
		dev_err(slave->bus->dev,
				"SDW_DP0_INT read failed:%d", status);
		return status;
	}

	do {

		if (status & SDW_DP0_INT_TEST_FAIL) {
			dev_err(&slave->dev, "Test fail for port 0");
			clear |= SDW_DP0_INT_TEST_FAIL;
		}

		/*
		 * Assumption: PORT_READY interrupt will be received only for
		 * ports implementing Channel Prepare state machine (CP_SM)
		 */

		if (status & SDW_DP0_INT_PORT_READY) {
			complete(&slave->port_ready[0]);
			clear |= SDW_DP0_INT_PORT_READY;
		}

		if (status & SDW_DP0_INT_BRA_FAILURE) {
			dev_err(&slave->dev, "BRA failed");
			clear |= SDW_DP0_INT_BRA_FAILURE;
		}

		impl_int_mask = SDW_DP0_INT_IMPDEF1 |
			SDW_DP0_INT_IMPDEF2 | SDW_DP0_INT_IMPDEF3;

		if (status & impl_int_mask) {
			clear |= impl_int_mask;
			*slave_status = clear;
		}

		/* clear the interrupt */
		ret = sdw_write(slave, SDW_DP0_INT, clear);
		if (ret < 0) {
			dev_err(slave->bus->dev,
				"SDW_DP0_INT write failed:%d", ret);
			return ret;
		}

		/* Read DP0 interrupt again */
		status2 = sdw_read(slave, SDW_DP0_INT);
		if (status2 < 0) {
			dev_err(slave->bus->dev,
				"SDW_DP0_INT read failed:%d", status2);
			return status2;
		}
		status &= status2;

		count++;

		/* we can get alerts while processing so keep retrying */
	} while (status != 0 && count < SDW_READ_INTR_CLEAR_RETRY);

	if (count == SDW_READ_INTR_CLEAR_RETRY)
		dev_warn(slave->bus->dev, "Reached MAX_RETRY on DP0 read");

	return ret;
}

static int sdw_handle_port_interrupt(struct sdw_slave *slave,
		int port, u8 *slave_status)
{
	u8 clear = 0, impl_int_mask;
	int status, status2, ret, count = 0;
	u32 addr;

	if (port == 0)
		return sdw_handle_dp0_interrupt(slave, slave_status);

	addr = SDW_DPN_INT(port);
	status = sdw_read(slave, addr);
	if (status < 0) {
		dev_err(slave->bus->dev,
				"SDW_DPN_INT read failed:%d", status);

		return status;
	}

	do {

		if (status & SDW_DPN_INT_TEST_FAIL) {
			dev_err(&slave->dev, "Test fail for port:%d", port);
			clear |= SDW_DPN_INT_TEST_FAIL;
		}

		/*
		 * Assumption: PORT_READY interrupt will be received only
		 * for ports implementing CP_SM.
		 */
		if (status & SDW_DPN_INT_PORT_READY) {
			complete(&slave->port_ready[port]);
			clear |= SDW_DPN_INT_PORT_READY;
		}

		impl_int_mask = SDW_DPN_INT_IMPDEF1 |
			SDW_DPN_INT_IMPDEF2 | SDW_DPN_INT_IMPDEF3;


		if (status & impl_int_mask) {
			clear |= impl_int_mask;
			*slave_status = clear;
		}

		/* clear the interrupt */
		ret = sdw_write(slave, addr, clear);
		if (ret < 0) {
			dev_err(slave->bus->dev,
					"SDW_DPN_INT write failed:%d", ret);
			return ret;
		}

		/* Read DPN interrupt again */
		status2 = sdw_read(slave, addr);
		if (status2 < 0) {
			dev_err(slave->bus->dev,
					"SDW_DPN_INT read failed:%d", status2);
			return status2;
		}
		status &= status2;

		count++;

		/* we can get alerts while processing so keep retrying */
	} while (status != 0 && count < SDW_READ_INTR_CLEAR_RETRY);

	if (count == SDW_READ_INTR_CLEAR_RETRY)
		dev_warn(slave->bus->dev, "Reached MAX_RETRY on port read");

	return ret;
}

static int sdw_handle_slave_alerts(struct sdw_slave *slave)
{
	struct sdw_slave_intr_status slave_intr;
	u8 clear = 0, bit, port_status[15];
	int port_num, stat, ret, count = 0;
	unsigned long port;
	bool slave_notify = false;
	u8 buf, buf2[2], _buf, _buf2[2];

	sdw_modify_slave_status(slave, SDW_SLAVE_ALERT);

	/* Read Instat 1, Instat 2 and Instat 3 registers */
	ret = buf = sdw_read(slave, SDW_SCP_INT1);
	if (ret < 0) {
		dev_err(slave->bus->dev,
					"SDW_SCP_INT1 read failed:%d", ret);
		return ret;
	}

	ret = sdw_nread(slave, SDW_SCP_INTSTAT2, 2, buf2);
	if (ret < 0) {
		dev_err(slave->bus->dev,
					"SDW_SCP_INT2/3 read failed:%d", ret);
		return ret;
	}

	do {
		/*
		 * Check parity, bus clash and Slave (impl defined)
		 * interrupt
		 */
		if (buf & SDW_SCP_INT1_PARITY) {
			dev_err(&slave->dev, "Parity error detected");
			clear |= SDW_SCP_INT1_PARITY;
		}

		if (buf & SDW_SCP_INT1_BUS_CLASH) {
			dev_err(&slave->dev, "Bus clash error detected");
			clear |= SDW_SCP_INT1_BUS_CLASH;
		}

		/*
		 * When bus clash or parity errors are detected, such errors
		 * are unlikely to be recoverable errors.
		 * TODO: In such scenario, reset bus. Make this configurable
		 * via sysfs property with bus reset being the default.
		 */

		if (buf & SDW_SCP_INT1_IMPL_DEF) {
			dev_dbg(&slave->dev, "Slave impl defined interrupt\n");
			clear |= SDW_SCP_INT1_IMPL_DEF;
			slave_notify = true;
		}

		/* Check port 0 - 3 interrupts */
		port = buf & SDW_SCP_INT1_PORT0_3;

		/* To get port number corresponding to bits, shift it */
		port = port >> SDW_REG_SHIFT(SDW_SCP_INT1_PORT0_3);
		for_each_set_bit(bit, &port, 8) {
			sdw_handle_port_interrupt(slave, bit,
						&port_status[bit]);

		}

		/* Check if cascade 2 interrupt is present */
		if (buf & SDW_SCP_INT1_SCP2_CASCADE) {
			port = buf2[0] & SDW_SCP_INTSTAT2_PORT4_10;
			for_each_set_bit(bit, &port, 8) {
				/* scp2 ports start from 4 */
				port_num = bit + 3;
				sdw_handle_port_interrupt(slave,
						port_num,
						&port_status[port_num]);
			}
		}

		/* now check last cascade */
		if (buf2[0] & SDW_SCP_INTSTAT2_SCP3_CASCADE) {
			port = buf2[1] & SDW_SCP_INTSTAT3_PORT11_14;
			for_each_set_bit(bit, &port, 8) {
				/* scp3 ports start from 11 */
				port_num = bit + 10;
				sdw_handle_port_interrupt(slave,
						port_num,
						&port_status[port_num]);
			}
		}

		/* Update the Slave driver */
		if (slave_notify && (slave->ops) &&
					(slave->ops->interrupt_callback)) {
			slave_intr.control_port = clear;
			memcpy(slave_intr.port, &port_status,
						sizeof(slave_intr.port));

			slave->ops->interrupt_callback(slave, &slave_intr);
		}

		/* Ack interrupt */
		ret = sdw_write(slave, SDW_SCP_INT1, clear);
		if (ret < 0) {
			dev_err(slave->bus->dev,
					"SDW_SCP_INT1 write failed:%d", ret);
			return ret;
		}

		/*
		 * Read status again to ensure no new interrupts arrived
		 * while servicing interrupts.
		 */
		ret = _buf = sdw_read(slave, SDW_SCP_INT1);
		if (ret < 0) {
			dev_err(slave->bus->dev,
					"SDW_SCP_INT1 read failed:%d", ret);
			return ret;
		}

		ret = sdw_nread(slave, SDW_SCP_INTSTAT2, 2, _buf2);
		if (ret < 0) {
			dev_err(slave->bus->dev,
					"SDW_SCP_INT2/3 read failed:%d", ret);
			return ret;
		}

		/* Make sure no interrupts are pending */
		buf &= _buf;
		buf2[0] &= _buf2[0];
		buf2[1] &= _buf2[1];
		stat = buf || buf2[0] || buf2[1];

		/*
		 * Exit loop if Slave is continuously in ALERT state even
		 * after servicing the interrupt multiple times.
		 */
		count++;

		/* we can get alerts while processing so keep retrying */
	} while (stat != 0 && count < SDW_READ_INTR_CLEAR_RETRY);

	if (count == SDW_READ_INTR_CLEAR_RETRY)
		dev_warn(slave->bus->dev, "Reached MAX_RETRY on alert read");

	return ret;
}

static int sdw_update_slave_status(struct sdw_slave *slave,
				enum sdw_slave_status status)
{
	if ((slave->ops) && (slave->ops->update_status))
		return slave->ops->update_status(slave, status);

	return 0;
}

/**
 * sdw_handle_slave_status() - Handle Slave status
 * @bus: SDW bus instance
 * @status: Status for all Slave(s)
 */
int sdw_handle_slave_status(struct sdw_bus *bus,
			enum sdw_slave_status status[])
{
	enum sdw_slave_status prev_status;
	struct sdw_slave *slave;
	int i, ret = 0;

	if (status[0] == SDW_SLAVE_ATTACHED) {
		ret = sdw_program_device_num(bus);
		if (ret)
			dev_err(bus->dev, "Slave attach failed: %d", ret);
	}

	/* Continue to check other slave statuses */
	for (i = 1; i <= SDW_MAX_DEVICES; i++) {
		mutex_lock(&bus->bus_lock);
		if (test_bit(i, bus->assigned) == false) {
			mutex_unlock(&bus->bus_lock);
			continue;
		}
		mutex_unlock(&bus->bus_lock);

		slave = sdw_get_slave(bus, i);
		if (!slave)
			continue;

		switch (status[i]) {
		case SDW_SLAVE_UNATTACHED:
			if (slave->status == SDW_SLAVE_UNATTACHED)
				break;

			sdw_modify_slave_status(slave, SDW_SLAVE_UNATTACHED);
			break;

		case SDW_SLAVE_ALERT:
			ret = sdw_handle_slave_alerts(slave);
			if (ret)
				dev_err(bus->dev,
					"Slave %d alert handling failed: %d",
					i, ret);
			break;

		case SDW_SLAVE_ATTACHED:
			if (slave->status == SDW_SLAVE_ATTACHED)
				break;

			prev_status = slave->status;
			sdw_modify_slave_status(slave, SDW_SLAVE_ATTACHED);

			if (prev_status == SDW_SLAVE_ALERT)
				break;

			ret = sdw_initialize_slave(slave);
			if (ret)
				dev_err(bus->dev,
					"Slave %d initialization failed: %d",
					i, ret);

			break;

		default:
			dev_err(bus->dev, "Invalid slave %d status:%d",
							i, status[i]);
			break;
		}

		ret = sdw_update_slave_status(slave, status[i]);
		if (ret)
			dev_err(slave->bus->dev,
				"Update Slave status failed:%d", ret);

	}

	return ret;
}
EXPORT_SYMBOL(sdw_handle_slave_status);