aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/mmc/mmc.c
blob: bfca5c176e8862c559e9f3abc1bf91c2ba9825c7 (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
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
/*
 *  linux/drivers/mmc/mmc.c
 *
 *  Copyright (C) 2003-2004 Russell King, All Rights Reserved.
 *  SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
 *  SD support Copyright (C) 2005 Pierre Ossman, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/pagemap.h>
#include <linux/err.h>
#include <asm/scatterlist.h>
#include <linux/scatterlist.h>

#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/protocol.h>

#include "mmc.h"

#ifdef CONFIG_MMC_DEBUG
#define DBG(x...)	printk(KERN_DEBUG x)
#else
#define DBG(x...)	do { } while (0)
#endif

#define CMD_RETRIES	3

/*
 * OCR Bit positions to 10s of Vdd mV.
 */
static const unsigned short mmc_ocr_bit_to_vdd[] = {
	150,	155,	160,	165,	170,	180,	190,	200,
	210,	220,	230,	240,	250,	260,	270,	280,
	290,	300,	310,	320,	330,	340,	350,	360
};

static const unsigned int tran_exp[] = {
	10000,		100000,		1000000,	10000000,
	0,		0,		0,		0
};

static const unsigned char tran_mant[] = {
	0,	10,	12,	13,	15,	20,	25,	30,
	35,	40,	45,	50,	55,	60,	70,	80,
};

static const unsigned int tacc_exp[] = {
	1,	10,	100,	1000,	10000,	100000,	1000000, 10000000,
};

static const unsigned int tacc_mant[] = {
	0,	10,	12,	13,	15,	20,	25,	30,
	35,	40,	45,	50,	55,	60,	70,	80,
};


/**
 *	mmc_request_done - finish processing an MMC command
 *	@host: MMC host which completed command
 *	@mrq: MMC request which completed
 *
 *	MMC drivers should call this function when they have completed
 *	their processing of a command.  This should be called before the
 *	data part of the command has completed.
 */
void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
{
	struct mmc_command *cmd = mrq->cmd;
	int err = mrq->cmd->error;
	DBG("MMC: req done (%02x): %d: %08x %08x %08x %08x\n", cmd->opcode,
	    err, cmd->resp[0], cmd->resp[1], cmd->resp[2], cmd->resp[3]);

	if (err && cmd->retries) {
		cmd->retries--;
		cmd->error = 0;
		host->ops->request(host, mrq);
	} else if (mrq->done) {
		mrq->done(mrq);
	}
}

EXPORT_SYMBOL(mmc_request_done);

/**
 *	mmc_start_request - start a command on a host
 *	@host: MMC host to start command on
 *	@mrq: MMC request to start
 *
 *	Queue a command on the specified host.  We expect the
 *	caller to be holding the host lock with interrupts disabled.
 */
void
mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
	DBG("MMC: starting cmd %02x arg %08x flags %08x\n",
	    mrq->cmd->opcode, mrq->cmd->arg, mrq->cmd->flags);

	WARN_ON(host->card_busy == NULL);

	mrq->cmd->error = 0;
	mrq->cmd->mrq = mrq;
	if (mrq->data) {
		mrq->cmd->data = mrq->data;
		mrq->data->error = 0;
		mrq->data->mrq = mrq;
		if (mrq->stop) {
			mrq->data->stop = mrq->stop;
			mrq->stop->error = 0;
			mrq->stop->mrq = mrq;
		}
	}
	host->ops->request(host, mrq);
}

EXPORT_SYMBOL(mmc_start_request);

static void mmc_wait_done(struct mmc_request *mrq)
{
	complete(mrq->done_data);
}

int mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
{
	DECLARE_COMPLETION(complete);

	mrq->done_data = &complete;
	mrq->done = mmc_wait_done;

	mmc_start_request(host, mrq);

	wait_for_completion(&complete);

	return 0;
}

EXPORT_SYMBOL(mmc_wait_for_req);

/**
 *	mmc_wait_for_cmd - start a command and wait for completion
 *	@host: MMC host to start command
 *	@cmd: MMC command to start
 *	@retries: maximum number of retries
 *
 *	Start a new MMC command for a host, and wait for the command
 *	to complete.  Return any error that occurred while the command
 *	was executing.  Do not attempt to parse the response.
 */
int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries)
{
	struct mmc_request mrq;

	BUG_ON(host->card_busy == NULL);

	memset(&mrq, 0, sizeof(struct mmc_request));

	memset(cmd->resp, 0, sizeof(cmd->resp));
	cmd->retries = retries;

	mrq.cmd = cmd;
	cmd->data = NULL;

	mmc_wait_for_req(host, &mrq);

	return cmd->error;
}

EXPORT_SYMBOL(mmc_wait_for_cmd);

/**
 *	mmc_wait_for_app_cmd - start an application command and wait for
 			       completion
 *	@host: MMC host to start command
 *	@rca: RCA to send MMC_APP_CMD to
 *	@cmd: MMC command to start
 *	@retries: maximum number of retries
 *
 *	Sends a MMC_APP_CMD, checks the card response, sends the command
 *	in the parameter and waits for it to complete. Return any error
 *	that occurred while the command was executing.  Do not attempt to
 *	parse the response.
 */
int mmc_wait_for_app_cmd(struct mmc_host *host, unsigned int rca,
	struct mmc_command *cmd, int retries)
{
	struct mmc_request mrq;
	struct mmc_command appcmd;

	int i, err;

	BUG_ON(host->card_busy == NULL);
	BUG_ON(retries < 0);

	err = MMC_ERR_INVALID;

	/*
	 * We have to resend MMC_APP_CMD for each attempt so
	 * we cannot use the retries field in mmc_command.
	 */
	for (i = 0;i <= retries;i++) {
		memset(&mrq, 0, sizeof(struct mmc_request));

		appcmd.opcode = MMC_APP_CMD;
		appcmd.arg = rca << 16;
		appcmd.flags = MMC_RSP_R1;
		appcmd.retries = 0;
		memset(appcmd.resp, 0, sizeof(appcmd.resp));
		appcmd.data = NULL;

		mrq.cmd = &appcmd;
		appcmd.data = NULL;

		mmc_wait_for_req(host, &mrq);

		if (appcmd.error) {
			err = appcmd.error;
			continue;
		}

		/* Check that card supported application commands */
		if (!(appcmd.resp[0] & R1_APP_CMD))
			return MMC_ERR_FAILED;

		memset(&mrq, 0, sizeof(struct mmc_request));

		memset(cmd->resp, 0, sizeof(cmd->resp));
		cmd->retries = 0;

		mrq.cmd = cmd;
		cmd->data = NULL;

		mmc_wait_for_req(host, &mrq);

		err = cmd->error;
		if (cmd->error == MMC_ERR_NONE)
			break;
	}

	return err;
}

EXPORT_SYMBOL(mmc_wait_for_app_cmd);

static int mmc_select_card(struct mmc_host *host, struct mmc_card *card);

/**
 *	__mmc_claim_host - exclusively claim a host
 *	@host: mmc host to claim
 *	@card: mmc card to claim host for
 *
 *	Claim a host for a set of operations.  If a valid card
 *	is passed and this wasn't the last card selected, select
 *	the card before returning.
 *
 *	Note: you should use mmc_card_claim_host or mmc_claim_host.
 */
int __mmc_claim_host(struct mmc_host *host, struct mmc_card *card)
{
	DECLARE_WAITQUEUE(wait, current);
	unsigned long flags;
	int err = 0;

	add_wait_queue(&host->wq, &wait);
	spin_lock_irqsave(&host->lock, flags);
	while (1) {
		set_current_state(TASK_UNINTERRUPTIBLE);
		if (host->card_busy == NULL)
			break;
		spin_unlock_irqrestore(&host->lock, flags);
		schedule();
		spin_lock_irqsave(&host->lock, flags);
	}
	set_current_state(TASK_RUNNING);
	host->card_busy = card;
	spin_unlock_irqrestore(&host->lock, flags);
	remove_wait_queue(&host->wq, &wait);

	if (card != (void *)-1) {
		err = mmc_select_card(host, card);
		if (err != MMC_ERR_NONE)
			return err;
	}

	return err;
}

EXPORT_SYMBOL(__mmc_claim_host);

/**
 *	mmc_release_host - release a host
 *	@host: mmc host to release
 *
 *	Release a MMC host, allowing others to claim the host
 *	for their operations.
 */
void mmc_release_host(struct mmc_host *host)
{
	unsigned long flags;

	BUG_ON(host->card_busy == NULL);

	spin_lock_irqsave(&host->lock, flags);
	host->card_busy = NULL;
	spin_unlock_irqrestore(&host->lock, flags);

	wake_up(&host->wq);
}

EXPORT_SYMBOL(mmc_release_host);

static int mmc_select_card(struct mmc_host *host, struct mmc_card *card)
{
	int err;
	struct mmc_command cmd;

	BUG_ON(host->card_busy == NULL);

	if (host->card_selected == card)
		return MMC_ERR_NONE;

	host->card_selected = card;

	cmd.opcode = MMC_SELECT_CARD;
	cmd.arg = card->rca << 16;
	cmd.flags = MMC_RSP_R1;

	err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
	if (err != MMC_ERR_NONE)
		return err;

	/*
	 * Default bus width is 1 bit.
	 */
	host->ios.bus_width = MMC_BUS_WIDTH_1;

	/*
	 * We can only change the bus width of the selected
	 * card so therefore we have to put the handling
	 * here.
	 */
	if (host->caps & MMC_CAP_4_BIT_DATA) {
		/*
		 * The card is in 1 bit mode by default so
		 * we only need to change if it supports the
		 * wider version.
		 */
		if (mmc_card_sd(card) &&
			(card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
			struct mmc_command cmd;
			cmd.opcode = SD_APP_SET_BUS_WIDTH;
			cmd.arg = SD_BUS_WIDTH_4;
			cmd.flags = MMC_RSP_R1;

			err = mmc_wait_for_app_cmd(host, card->rca, &cmd,
				CMD_RETRIES);
			if (err != MMC_ERR_NONE)
				return err;

			host->ios.bus_width = MMC_BUS_WIDTH_4;
		}
	}

	host->ops->set_ios(host, &host->ios);

	return MMC_ERR_NONE;
}

/*
 * Ensure that no card is selected.
 */
static void mmc_deselect_cards(struct mmc_host *host)
{
	struct mmc_command cmd;

	if (host->card_selected) {
		host->card_selected = NULL;

		cmd.opcode = MMC_SELECT_CARD;
		cmd.arg = 0;
		cmd.flags = MMC_RSP_NONE;

		mmc_wait_for_cmd(host, &cmd, 0);
	}
}


static inline void mmc_delay(unsigned int ms)
{
	if (ms < HZ / 1000) {
		yield();
		mdelay(ms);
	} else {
		msleep_interruptible (ms);
	}
}

/*
 * Mask off any voltages we don't support and select
 * the lowest voltage
 */
static u32 mmc_select_voltage(struct mmc_host *host, u32 ocr)
{
	int bit;

	ocr &= host->ocr_avail;

	bit = ffs(ocr);
	if (bit) {
		bit -= 1;

		ocr = 3 << bit;

		host->ios.vdd = bit;
		host->ops->set_ios(host, &host->ios);
	} else {
		ocr = 0;
	}

	return ocr;
}

#define UNSTUFF_BITS(resp,start,size)					\
	({								\
		const int __size = size;				\
		const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1;	\
		const int __off = 3 - ((start) / 32);			\
		const int __shft = (start) & 31;			\
		u32 __res;						\
									\
		__res = resp[__off] >> __shft;				\
		if (__size + __shft > 32)				\
			__res |= resp[__off-1] << ((32 - __shft) % 32);	\
		__res & __mask;						\
	})

/*
 * Given the decoded CSD structure, decode the raw CID to our CID structure.
 */
static void mmc_decode_cid(struct mmc_card *card)
{
	u32 *resp = card->raw_cid;

	memset(&card->cid, 0, sizeof(struct mmc_cid));

	if (mmc_card_sd(card)) {
		/*
		 * SD doesn't currently have a version field so we will
		 * have to assume we can parse this.
		 */
		card->cid.manfid		= UNSTUFF_BITS(resp, 120, 8);
		card->cid.oemid			= UNSTUFF_BITS(resp, 104, 16);
		card->cid.prod_name[0]		= UNSTUFF_BITS(resp, 96, 8);
		card->cid.prod_name[1]		= UNSTUFF_BITS(resp, 88, 8);
		card->cid.prod_name[2]		= UNSTUFF_BITS(resp, 80, 8);
		card->cid.prod_name[3]		= UNSTUFF_BITS(resp, 72, 8);
		card->cid.prod_name[4]		= UNSTUFF_BITS(resp, 64, 8);
		card->cid.hwrev			= UNSTUFF_BITS(resp, 60, 4);
		card->cid.fwrev			= UNSTUFF_BITS(resp, 56, 4);
		card->cid.serial		= UNSTUFF_BITS(resp, 24, 32);
		card->cid.year			= UNSTUFF_BITS(resp, 12, 8);
		card->cid.month			= UNSTUFF_BITS(resp, 8, 4);

		card->cid.year += 2000; /* SD cards year offset */
	} else {
		/*
		 * The selection of the format here is based upon published
		 * specs from sandisk and from what people have reported.
		 */
		switch (card->csd.mmca_vsn) {
		case 0: /* MMC v1.0 - v1.2 */
		case 1: /* MMC v1.4 */
			card->cid.manfid	= UNSTUFF_BITS(resp, 104, 24);
			card->cid.prod_name[0]	= UNSTUFF_BITS(resp, 96, 8);
			card->cid.prod_name[1]	= UNSTUFF_BITS(resp, 88, 8);
			card->cid.prod_name[2]	= UNSTUFF_BITS(resp, 80, 8);
			card->cid.prod_name[3]	= UNSTUFF_BITS(resp, 72, 8);
			card->cid.prod_name[4]	= UNSTUFF_BITS(resp, 64, 8);
			card->cid.prod_name[5]	= UNSTUFF_BITS(resp, 56, 8);
			card->cid.prod_name[6]	= UNSTUFF_BITS(resp, 48, 8);
			card->cid.hwrev		= UNSTUFF_BITS(resp, 44, 4);
			card->cid.fwrev		= UNSTUFF_BITS(resp, 40, 4);
			card->cid.serial	= UNSTUFF_BITS(resp, 16, 24);
			card->cid.month		= UNSTUFF_BITS(resp, 12, 4);
			card->cid.year		= UNSTUFF_BITS(resp, 8, 4) + 1997;
			break;

		case 2: /* MMC v2.0 - v2.2 */
		case 3: /* MMC v3.1 - v3.3 */
		case 4: /* MMC v4 */
			card->cid.manfid	= UNSTUFF_BITS(resp, 120, 8);
			card->cid.oemid		= UNSTUFF_BITS(resp, 104, 16);
			card->cid.prod_name[0]	= UNSTUFF_BITS(resp, 96, 8);
			card->cid.prod_name[1]	= UNSTUFF_BITS(resp, 88, 8);
			card->cid.prod_name[2]	= UNSTUFF_BITS(resp, 80, 8);
			card->cid.prod_name[3]	= UNSTUFF_BITS(resp, 72, 8);
			card->cid.prod_name[4]	= UNSTUFF_BITS(resp, 64, 8);
			card->cid.prod_name[5]	= UNSTUFF_BITS(resp, 56, 8);
			card->cid.serial	= UNSTUFF_BITS(resp, 16, 32);
			card->cid.month		= UNSTUFF_BITS(resp, 12, 4);
			card->cid.year		= UNSTUFF_BITS(resp, 8, 4) + 1997;
			break;

		default:
			printk("%s: card has unknown MMCA version %d\n",
				mmc_hostname(card->host), card->csd.mmca_vsn);
			mmc_card_set_bad(card);
			break;
		}
	}
}

/*
 * Given a 128-bit response, decode to our card CSD structure.
 */
static void mmc_decode_csd(struct mmc_card *card)
{
	struct mmc_csd *csd = &card->csd;
	unsigned int e, m, csd_struct;
	u32 *resp = card->raw_csd;

	if (mmc_card_sd(card)) {
		csd_struct = UNSTUFF_BITS(resp, 126, 2);
		if (csd_struct != 0) {
			printk("%s: unrecognised CSD structure version %d\n",
				mmc_hostname(card->host), csd_struct);
			mmc_card_set_bad(card);
			return;
		}

		m = UNSTUFF_BITS(resp, 115, 4);
		e = UNSTUFF_BITS(resp, 112, 3);
		csd->tacc_ns	 = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
		csd->tacc_clks	 = UNSTUFF_BITS(resp, 104, 8) * 100;

		m = UNSTUFF_BITS(resp, 99, 4);
		e = UNSTUFF_BITS(resp, 96, 3);
		csd->max_dtr	  = tran_exp[e] * tran_mant[m];
		csd->cmdclass	  = UNSTUFF_BITS(resp, 84, 12);

		e = UNSTUFF_BITS(resp, 47, 3);
		m = UNSTUFF_BITS(resp, 62, 12);
		csd->capacity	  = (1 + m) << (e + 2);

		csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
		csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
		csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
		csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
		csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
		csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
	} else {
		/*
		 * We only understand CSD structure v1.1 and v1.2.
		 * v1.2 has extra information in bits 15, 11 and 10.
		 */
		csd_struct = UNSTUFF_BITS(resp, 126, 2);
		if (csd_struct != 1 && csd_struct != 2) {
			printk("%s: unrecognised CSD structure version %d\n",
				mmc_hostname(card->host), csd_struct);
			mmc_card_set_bad(card);
			return;
		}

		csd->mmca_vsn	 = UNSTUFF_BITS(resp, 122, 4);
		m = UNSTUFF_BITS(resp, 115, 4);
		e = UNSTUFF_BITS(resp, 112, 3);
		csd->tacc_ns	 = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
		csd->tacc_clks	 = UNSTUFF_BITS(resp, 104, 8) * 100;

		m = UNSTUFF_BITS(resp, 99, 4);
		e = UNSTUFF_BITS(resp, 96, 3);
		csd->max_dtr	  = tran_exp[e] * tran_mant[m];
		csd->cmdclass	  = UNSTUFF_BITS(resp, 84, 12);

		e = UNSTUFF_BITS(resp, 47, 3);
		m = UNSTUFF_BITS(resp, 62, 12);
		csd->capacity	  = (1 + m) << (e + 2);

		csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
		csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
		csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
		csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
		csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
		csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
	}
}

/*
 * Given a 64-bit response, decode to our card SCR structure.
 */
static void mmc_decode_scr(struct mmc_card *card)
{
	struct sd_scr *scr = &card->scr;
	unsigned int scr_struct;
	u32 resp[4];

	BUG_ON(!mmc_card_sd(card));

	resp[3] = card->raw_scr[1];
	resp[2] = card->raw_scr[0];

	scr_struct = UNSTUFF_BITS(resp, 60, 4);
	if (scr_struct != 0) {
		printk("%s: unrecognised SCR structure version %d\n",
			mmc_hostname(card->host), scr_struct);
		mmc_card_set_bad(card);
		return;
	}

	scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4);
	scr->bus_widths = UNSTUFF_BITS(resp, 48, 4);
}

/*
 * Locate a MMC card on this MMC host given a raw CID.
 */
static struct mmc_card *mmc_find_card(struct mmc_host *host, u32 *raw_cid)
{
	struct mmc_card *card;

	list_for_each_entry(card, &host->cards, node) {
		if (memcmp(card->raw_cid, raw_cid, sizeof(card->raw_cid)) == 0)
			return card;
	}
	return NULL;
}

/*
 * Allocate a new MMC card, and assign a unique RCA.
 */
static struct mmc_card *
mmc_alloc_card(struct mmc_host *host, u32 *raw_cid, unsigned int *frca)
{
	struct mmc_card *card, *c;
	unsigned int rca = *frca;

	card = kmalloc(sizeof(struct mmc_card), GFP_KERNEL);
	if (!card)
		return ERR_PTR(-ENOMEM);

	mmc_init_card(card, host);
	memcpy(card->raw_cid, raw_cid, sizeof(card->raw_cid));

 again:
	list_for_each_entry(c, &host->cards, node)
		if (c->rca == rca) {
			rca++;
			goto again;
		}

	card->rca = rca;

	*frca = rca;

	return card;
}

/*
 * Tell attached cards to go to IDLE state
 */
static void mmc_idle_cards(struct mmc_host *host)
{
	struct mmc_command cmd;

	host->ios.chip_select = MMC_CS_HIGH;
	host->ops->set_ios(host, &host->ios);

	mmc_delay(1);

	cmd.opcode = MMC_GO_IDLE_STATE;
	cmd.arg = 0;
	cmd.flags = MMC_RSP_NONE;

	mmc_wait_for_cmd(host, &cmd, 0);

	mmc_delay(1);

	host->ios.chip_select = MMC_CS_DONTCARE;
	host->ops->set_ios(host, &host->ios);

	mmc_delay(1);
}

/*
 * Apply power to the MMC stack.  This is a two-stage process.
 * First, we enable power to the card without the clock running.
 * We then wait a bit for the power to stabilise.  Finally,
 * enable the bus drivers and clock to the card.
 *
 * We must _NOT_ enable the clock prior to power stablising.
 *
 * If a host does all the power sequencing itself, ignore the
 * initial MMC_POWER_UP stage.
 */
static void mmc_power_up(struct mmc_host *host)
{
	int bit = fls(host->ocr_avail) - 1;

	host->ios.vdd = bit;
	host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
	host->ios.chip_select = MMC_CS_DONTCARE;
	host->ios.power_mode = MMC_POWER_UP;
	host->ios.bus_width = MMC_BUS_WIDTH_1;
	host->ops->set_ios(host, &host->ios);

	mmc_delay(1);

	host->ios.clock = host->f_min;
	host->ios.power_mode = MMC_POWER_ON;
	host->ops->set_ios(host, &host->ios);

	mmc_delay(2);
}

static void mmc_power_off(struct mmc_host *host)
{
	host->ios.clock = 0;
	host->ios.vdd = 0;
	host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
	host->ios.chip_select = MMC_CS_DONTCARE;
	host->ios.power_mode = MMC_POWER_OFF;
	host->ios.bus_width = MMC_BUS_WIDTH_1;
	host->ops->set_ios(host, &host->ios);
}

static int mmc_send_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr)
{
	struct mmc_command cmd;
	int i, err = 0;

	cmd.opcode = MMC_SEND_OP_COND;
	cmd.arg = ocr;
	cmd.flags = MMC_RSP_R3;

	for (i = 100; i; i--) {
		err = mmc_wait_for_cmd(host, &cmd, 0);
		if (err != MMC_ERR_NONE)
			break;

		if (cmd.resp[0] & MMC_CARD_BUSY || ocr == 0)
			break;

		err = MMC_ERR_TIMEOUT;

		mmc_delay(10);
	}

	if (rocr)
		*rocr = cmd.resp[0];

	return err;
}

static int mmc_send_app_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr)
{
	struct mmc_command cmd;
	int i, err = 0;

	cmd.opcode = SD_APP_OP_COND;
	cmd.arg = ocr;
	cmd.flags = MMC_RSP_R3;

	for (i = 100; i; i--) {
		err = mmc_wait_for_app_cmd(host, 0, &cmd, CMD_RETRIES);
		if (err != MMC_ERR_NONE)
			break;

		if (cmd.resp[0] & MMC_CARD_BUSY || ocr == 0)
			break;

		err = MMC_ERR_TIMEOUT;

		mmc_delay(10);
	}

	if (rocr)
		*rocr = cmd.resp[0];

	return err;
}

/*
 * Discover cards by requesting their CID.  If this command
 * times out, it is not an error; there are no further cards
 * to be discovered.  Add new cards to the list.
 *
 * Create a mmc_card entry for each discovered card, assigning
 * it an RCA, and save the raw CID for decoding later.
 */
static void mmc_discover_cards(struct mmc_host *host)
{
	struct mmc_card *card;
	unsigned int first_rca = 1, err;

	while (1) {
		struct mmc_command cmd;

		cmd.opcode = MMC_ALL_SEND_CID;
		cmd.arg = 0;
		cmd.flags = MMC_RSP_R2;

		err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
		if (err == MMC_ERR_TIMEOUT) {
			err = MMC_ERR_NONE;
			break;
		}
		if (err != MMC_ERR_NONE) {
			printk(KERN_ERR "%s: error requesting CID: %d\n",
				mmc_hostname(host), err);
			break;
		}

		card = mmc_find_card(host, cmd.resp);
		if (!card) {
			card = mmc_alloc_card(host, cmd.resp, &first_rca);
			if (IS_ERR(card)) {
				err = PTR_ERR(card);
				break;
			}
			list_add(&card->node, &host->cards);
		}

		card->state &= ~MMC_STATE_DEAD;

		if (host->mode == MMC_MODE_SD) {
			mmc_card_set_sd(card);

			cmd.opcode = SD_SEND_RELATIVE_ADDR;
			cmd.arg = 0;
			cmd.flags = MMC_RSP_R6;

			err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
			if (err != MMC_ERR_NONE)
				mmc_card_set_dead(card);
			else {
				card->rca = cmd.resp[0] >> 16;

				if (!host->ops->get_ro) {
					printk(KERN_WARNING "%s: host does not "
						"support reading read-only "
						"switch. assuming write-enable.\n",
						mmc_hostname(host));
				} else {
					if (host->ops->get_ro(host))
						mmc_card_set_readonly(card);
				}
			}
		} else {
			cmd.opcode = MMC_SET_RELATIVE_ADDR;
			cmd.arg = card->rca << 16;
			cmd.flags = MMC_RSP_R1;

			err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
			if (err != MMC_ERR_NONE)
				mmc_card_set_dead(card);
		}
	}
}

static void mmc_read_csds(struct mmc_host *host)
{
	struct mmc_card *card;

	list_for_each_entry(card, &host->cards, node) {
		struct mmc_command cmd;
		int err;

		if (card->state & (MMC_STATE_DEAD|MMC_STATE_PRESENT))
			continue;

		cmd.opcode = MMC_SEND_CSD;
		cmd.arg = card->rca << 16;
		cmd.flags = MMC_RSP_R2;

		err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
		if (err != MMC_ERR_NONE) {
			mmc_card_set_dead(card);
			continue;
		}

		memcpy(card->raw_csd, cmd.resp, sizeof(card->raw_csd));

		mmc_decode_csd(card);
		mmc_decode_cid(card);
	}
}

static void mmc_read_scrs(struct mmc_host *host)
{
	int err;
	struct mmc_card *card;

	struct mmc_request mrq;
	struct mmc_command cmd;
	struct mmc_data data;

	struct scatterlist sg;

	list_for_each_entry(card, &host->cards, node) {
		if (card->state & (MMC_STATE_DEAD|MMC_STATE_PRESENT))
			continue;
		if (!mmc_card_sd(card))
			continue;

		err = mmc_select_card(host, card);
		if (err != MMC_ERR_NONE) {
			mmc_card_set_dead(card);
			continue;
		}

		memset(&cmd, 0, sizeof(struct mmc_command));

		cmd.opcode = MMC_APP_CMD;
		cmd.arg = card->rca << 16;
		cmd.flags = MMC_RSP_R1;

		err = mmc_wait_for_cmd(host, &cmd, 0);
		if ((err != MMC_ERR_NONE) || !(cmd.resp[0] & R1_APP_CMD)) {
			mmc_card_set_dead(card);
			continue;
		}

		memset(&cmd, 0, sizeof(struct mmc_command));

		cmd.opcode = SD_APP_SEND_SCR;
		cmd.arg = 0;
		cmd.flags = MMC_RSP_R1;

		memset(&data, 0, sizeof(struct mmc_data));

		data.timeout_ns = card->csd.tacc_ns * 10;
		data.timeout_clks = card->csd.tacc_clks * 10;
		data.blksz_bits = 3;
		data.blocks = 1;
		data.flags = MMC_DATA_READ;
		data.sg = &sg;
		data.sg_len = 1;

		memset(&mrq, 0, sizeof(struct mmc_request));

		mrq.cmd = &cmd;
		mrq.data = &data;

		sg_init_one(&sg, (u8*)card->raw_scr, 8);

		mmc_wait_for_req(host, &mrq);

		if (cmd.error != MMC_ERR_NONE || data.error != MMC_ERR_NONE) {
			mmc_card_set_dead(card);
			continue;
		}

		card->raw_scr[0] = ntohl(card->raw_scr[0]);
		card->raw_scr[1] = ntohl(card->raw_scr[1]);

		mmc_decode_scr(card);
	}

	mmc_deselect_cards(host);
}

static unsigned int mmc_calculate_clock(struct mmc_host *host)
{
	struct mmc_card *card;
	unsigned int max_dtr = host->f_max;

	list_for_each_entry(card, &host->cards, node)
		if (!mmc_card_dead(card) && max_dtr > card->csd.max_dtr)
			max_dtr = card->csd.max_dtr;

	DBG("MMC: selected %d.%03dMHz transfer rate\n",
	    max_dtr / 1000000, (max_dtr / 1000) % 1000);

	return max_dtr;
}

/*
 * Check whether cards we already know about are still present.
 * We do this by requesting status, and checking whether a card
 * responds.
 *
 * A request for status does not cause a state change in data
 * transfer mode.
 */
static void mmc_check_cards(struct mmc_host *host)
{
	struct list_head *l, *n;

	mmc_deselect_cards(host);

	list_for_each_safe(l, n, &host->cards) {
		struct mmc_card *card = mmc_list_to_card(l);
		struct mmc_command cmd;
		int err;

		cmd.opcode = MMC_SEND_STATUS;
		cmd.arg = card->rca << 16;
		cmd.flags = MMC_RSP_R1;

		err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
		if (err == MMC_ERR_NONE)
			continue;

		mmc_card_set_dead(card);
	}
}

static void mmc_setup(struct mmc_host *host)
{
	if (host->ios.power_mode != MMC_POWER_ON) {
		int err;
		u32 ocr;

		host->mode = MMC_MODE_SD;

		mmc_power_up(host);
		mmc_idle_cards(host);

		err = mmc_send_app_op_cond(host, 0, &ocr);

		/*
		 * If we fail to detect any SD cards then try
		 * searching for MMC cards.
		 */
		if (err != MMC_ERR_NONE) {
			host->mode = MMC_MODE_MMC;

			err = mmc_send_op_cond(host, 0, &ocr);
			if (err != MMC_ERR_NONE)
				return;
		}

		host->ocr = mmc_select_voltage(host, ocr);

		/*
		 * Since we're changing the OCR value, we seem to
		 * need to tell some cards to go back to the idle
		 * state.  We wait 1ms to give cards time to
		 * respond.
		 */
		if (host->ocr)
			mmc_idle_cards(host);
	} else {
		host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
		host->ios.clock = host->f_min;
		host->ops->set_ios(host, &host->ios);

		/*
		 * We should remember the OCR mask from the existing
		 * cards, and detect the new cards OCR mask, combine
		 * the two and re-select the VDD.  However, if we do
		 * change VDD, we should do an idle, and then do a
		 * full re-initialisation.  We would need to notify
		 * drivers so that they can re-setup the cards as
		 * well, while keeping their queues at bay.
		 *
		 * For the moment, we take the easy way out - if the
		 * new cards don't like our currently selected VDD,
		 * they drop off the bus.
		 */
	}

	if (host->ocr == 0)
		return;

	/*
	 * Send the selected OCR multiple times... until the cards
	 * all get the idea that they should be ready for CMD2.
	 * (My SanDisk card seems to need this.)
	 */
	if (host->mode == MMC_MODE_SD)
		mmc_send_app_op_cond(host, host->ocr, NULL);
	else
		mmc_send_op_cond(host, host->ocr, NULL);

	mmc_discover_cards(host);

	/*
	 * Ok, now switch to push-pull mode.
	 */
	host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
	host->ops->set_ios(host, &host->ios);

	mmc_read_csds(host);

	if (host->mode == MMC_MODE_SD)
		mmc_read_scrs(host);
}


/**
 *	mmc_detect_change - process change of state on a MMC socket
 *	@host: host which changed state.
 *	@delay: optional delay to wait before detection (jiffies)
 *
 *	All we know is that card(s) have been inserted or removed
 *	from the socket(s).  We don't know which socket or cards.
 */
void mmc_detect_change(struct mmc_host *host, unsigned long delay)
{
	if (delay)
		schedule_delayed_work(&host->detect, delay);
	else
		schedule_work(&host->detect);
}

EXPORT_SYMBOL(mmc_detect_change);


static void mmc_rescan(void *data)
{
	struct mmc_host *host = data;
	struct list_head *l, *n;

	mmc_claim_host(host);

	if (host->ios.power_mode == MMC_POWER_ON)
		mmc_check_cards(host);

	mmc_setup(host);

	if (!list_empty(&host->cards)) {
		/*
		 * (Re-)calculate the fastest clock rate which the
		 * attached cards and the host support.
		 */
		host->ios.clock = mmc_calculate_clock(host);
		host->ops->set_ios(host, &host->ios);
	}

	mmc_release_host(host);

	list_for_each_safe(l, n, &host->cards) {
		struct mmc_card *card = mmc_list_to_card(l);

		/*
		 * If this is a new and good card, register it.
		 */
		if (!mmc_card_present(card) && !mmc_card_dead(card)) {
			if (mmc_register_card(card))
				mmc_card_set_dead(card);
			else
				mmc_card_set_present(card);
		}

		/*
		 * If this card is dead, destroy it.
		 */
		if (mmc_card_dead(card)) {
			list_del(&card->node);
			mmc_remove_card(card);
		}
	}

	/*
	 * If we discover that there are no cards on the
	 * bus, turn off the clock and power down.
	 */
	if (list_empty(&host->cards))
		mmc_power_off(host);
}


/**
 *	mmc_alloc_host - initialise the per-host structure.
 *	@extra: sizeof private data structure
 *	@dev: pointer to host device model structure
 *
 *	Initialise the per-host structure.
 */
struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
{
	struct mmc_host *host;

	host = mmc_alloc_host_sysfs(extra, dev);
	if (host) {
		spin_lock_init(&host->lock);
		init_waitqueue_head(&host->wq);
		INIT_LIST_HEAD(&host->cards);
		INIT_WORK(&host->detect, mmc_rescan, host);

		/*
		 * By default, hosts do not support SGIO or large requests.
		 * They have to set these according to their abilities.
		 */
		host->max_hw_segs = 1;
		host->max_phys_segs = 1;
		host->max_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
		host->max_seg_size = PAGE_CACHE_SIZE;
	}

	return host;
}

EXPORT_SYMBOL(mmc_alloc_host);

/**
 *	mmc_add_host - initialise host hardware
 *	@host: mmc host
 */
int mmc_add_host(struct mmc_host *host)
{
	int ret;

	ret = mmc_add_host_sysfs(host);
	if (ret == 0) {
		mmc_power_off(host);
		mmc_detect_change(host, 0);
	}

	return ret;
}

EXPORT_SYMBOL(mmc_add_host);

/**
 *	mmc_remove_host - remove host hardware
 *	@host: mmc host
 *
 *	Unregister and remove all cards associated with this host,
 *	and power down the MMC bus.
 */
void mmc_remove_host(struct mmc_host *host)
{
	struct list_head *l, *n;

	list_for_each_safe(l, n, &host->cards) {
		struct mmc_card *card = mmc_list_to_card(l);

		mmc_remove_card(card);
	}

	mmc_power_off(host);
	mmc_remove_host_sysfs(host);
}

EXPORT_SYMBOL(mmc_remove_host);

/**
 *	mmc_free_host - free the host structure
 *	@host: mmc host
 *
 *	Free the host once all references to it have been dropped.
 */
void mmc_free_host(struct mmc_host *host)
{
	flush_scheduled_work();
	mmc_free_host_sysfs(host);
}

EXPORT_SYMBOL(mmc_free_host);

#ifdef CONFIG_PM

/**
 *	mmc_suspend_host - suspend a host
 *	@host: mmc host
 *	@state: suspend mode (PM_SUSPEND_xxx)
 */
int mmc_suspend_host(struct mmc_host *host, pm_message_t state)
{
	mmc_claim_host(host);
	mmc_deselect_cards(host);
	mmc_power_off(host);
	mmc_release_host(host);

	return 0;
}

EXPORT_SYMBOL(mmc_suspend_host);

/**
 *	mmc_resume_host - resume a previously suspended host
 *	@host: mmc host
 */
int mmc_resume_host(struct mmc_host *host)
{
	mmc_rescan(host);

	return 0;
}

EXPORT_SYMBOL(mmc_resume_host);

#endif

MODULE_LICENSE("GPL");