aboutsummaryrefslogtreecommitdiff
path: root/drivers/mmc/at91_mci.c
blob: 08a33c33f6edbb98ddd1dbd044f4f3848123bde4 (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
998
999
1000
/*
 *  linux/drivers/mmc/at91_mci.c - ATMEL AT91 MCI Driver
 *
 *  Copyright (C) 2005 Cougar Creek Computing Devices Ltd, All Rights Reserved
 *
 *  Copyright (C) 2006 Malcolm Noyes
 *
 * 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.
 */

/*
   This is the AT91 MCI driver that has been tested with both MMC cards
   and SD-cards.  Boards that support write protect are now supported.
   The CCAT91SBC001 board does not support SD cards.

   The three entry points are at91_mci_request, at91_mci_set_ios
   and at91_mci_get_ro.

   SET IOS
     This configures the device to put it into the correct mode and clock speed
     required.

   MCI REQUEST
     MCI request processes the commands sent in the mmc_request structure. This
     can consist of a processing command and a stop command in the case of
     multiple block transfers.

     There are three main types of request, commands, reads and writes.

     Commands are straight forward. The command is submitted to the controller and
     the request function returns. When the controller generates an interrupt to indicate
     the command is finished, the response to the command are read and the mmc_request_done
     function called to end the request.

     Reads and writes work in a similar manner to normal commands but involve the PDC (DMA)
     controller to manage the transfers.

     A read is done from the controller directly to the scatterlist passed in from the request.
     Due to a bug in the AT91RM9200 controller, when a read is completed, all the words are byte
     swapped in the scatterlist buffers.  AT91SAM926x are not affected by this bug.

     The sequence of read interrupts is: ENDRX, RXBUFF, CMDRDY

     A write is slightly different in that the bytes to write are read from the scatterlist
     into a dma memory buffer (this is in case the source buffer should be read only). The
     entire write buffer is then done from this single dma memory buffer.

     The sequence of write interrupts is: ENDTX, TXBUFE, NOTBUSY, CMDRDY

   GET RO
     Gets the status of the write protect pin, if available.
*/

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/dma-mapping.h>
#include <linux/clk.h>

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

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/mach/mmc.h>
#include <asm/arch/board.h>
#include <asm/arch/cpu.h>
#include <asm/arch/gpio.h>
#include <asm/arch/at91_mci.h>
#include <asm/arch/at91_pdc.h>

#define DRIVER_NAME "at91_mci"

#undef	SUPPORT_4WIRE

#define FL_SENT_COMMAND	(1 << 0)
#define FL_SENT_STOP	(1 << 1)

#define AT91_MCI_ERRORS	(AT91_MCI_RINDE | AT91_MCI_RDIRE | AT91_MCI_RCRCE	\
		| AT91_MCI_RENDE | AT91_MCI_RTOE | AT91_MCI_DCRCE		\
		| AT91_MCI_DTOE | AT91_MCI_OVRE | AT91_MCI_UNRE)			

#define at91_mci_read(host, reg)	__raw_readl((host)->baseaddr + (reg))
#define at91_mci_write(host, reg, val)	__raw_writel((val), (host)->baseaddr + (reg))


/*
 * Low level type for this driver
 */
struct at91mci_host
{
	struct mmc_host *mmc;
	struct mmc_command *cmd;
	struct mmc_request *request;

	void __iomem *baseaddr;
	int irq;

	struct at91_mmc_data *board;
	int present;

	struct clk *mci_clk;

	/*
	 * Flag indicating when the command has been sent. This is used to
	 * work out whether or not to send the stop
	 */
	unsigned int flags;
	/* flag for current bus settings */
	u32 bus_mode;

	/* DMA buffer used for transmitting */
	unsigned int* buffer;
	dma_addr_t physical_address;
	unsigned int total_length;

	/* Latest in the scatterlist that has been enabled for transfer, but not freed */
	int in_use_index;

	/* Latest in the scatterlist that has been enabled for transfer */
	int transfer_index;
};

/*
 * Copy from sg to a dma block - used for transfers
 */
static inline void at91mci_sg_to_dma(struct at91mci_host *host, struct mmc_data *data)
{
	unsigned int len, i, size;
	unsigned *dmabuf = host->buffer;

	size = host->total_length;
	len = data->sg_len;

	/*
	 * Just loop through all entries. Size might not
	 * be the entire list though so make sure that
	 * we do not transfer too much.
	 */
	for (i = 0; i < len; i++) {
		struct scatterlist *sg;
		int amount;
		unsigned int *sgbuffer;

		sg = &data->sg[i];

		sgbuffer = kmap_atomic(sg->page, KM_BIO_SRC_IRQ) + sg->offset;
		amount = min(size, sg->length);
		size -= amount;

		if (cpu_is_at91rm9200()) {	/* AT91RM9200 errata */
			int index;

			for (index = 0; index < (amount / 4); index++)
				*dmabuf++ = swab32(sgbuffer[index]);
		}
		else
			memcpy(dmabuf, sgbuffer, amount);

		kunmap_atomic(sgbuffer, KM_BIO_SRC_IRQ);

		if (size == 0)
			break;
	}

	/*
	 * Check that we didn't get a request to transfer
	 * more data than can fit into the SG list.
	 */
	BUG_ON(size != 0);
}

/*
 * Prepare a dma read
 */
static void at91mci_pre_dma_read(struct at91mci_host *host)
{
	int i;
	struct scatterlist *sg;
	struct mmc_command *cmd;
	struct mmc_data *data;

	pr_debug("pre dma read\n");

	cmd = host->cmd;
	if (!cmd) {
		pr_debug("no command\n");
		return;
	}

	data = cmd->data;
	if (!data) {
		pr_debug("no data\n");
		return;
	}

	for (i = 0; i < 2; i++) {
		/* nothing left to transfer */
		if (host->transfer_index >= data->sg_len) {
			pr_debug("Nothing left to transfer (index = %d)\n", host->transfer_index);
			break;
		}

		/* Check to see if this needs filling */
		if (i == 0) {
			if (at91_mci_read(host, AT91_PDC_RCR) != 0) {
				pr_debug("Transfer active in current\n");
				continue;
			}
		}
		else {
			if (at91_mci_read(host, AT91_PDC_RNCR) != 0) {
				pr_debug("Transfer active in next\n");
				continue;
			}
		}

		/* Setup the next transfer */
		pr_debug("Using transfer index %d\n", host->transfer_index);

		sg = &data->sg[host->transfer_index++];
		pr_debug("sg = %p\n", sg);

		sg->dma_address = dma_map_page(NULL, sg->page, sg->offset, sg->length, DMA_FROM_DEVICE);

		pr_debug("dma address = %08X, length = %d\n", sg->dma_address, sg->length);

		if (i == 0) {
			at91_mci_write(host, AT91_PDC_RPR, sg->dma_address);
			at91_mci_write(host, AT91_PDC_RCR, sg->length / 4);
		}
		else {
			at91_mci_write(host, AT91_PDC_RNPR, sg->dma_address);
			at91_mci_write(host, AT91_PDC_RNCR, sg->length / 4);
		}
	}

	pr_debug("pre dma read done\n");
}

/*
 * Handle after a dma read
 */
static void at91mci_post_dma_read(struct at91mci_host *host)
{
	struct mmc_command *cmd;
	struct mmc_data *data;

	pr_debug("post dma read\n");

	cmd = host->cmd;
	if (!cmd) {
		pr_debug("no command\n");
		return;
	}

	data = cmd->data;
	if (!data) {
		pr_debug("no data\n");
		return;
	}

	while (host->in_use_index < host->transfer_index) {
		unsigned int *buffer;

		struct scatterlist *sg;

		pr_debug("finishing index %d\n", host->in_use_index);

		sg = &data->sg[host->in_use_index++];

		pr_debug("Unmapping page %08X\n", sg->dma_address);

		dma_unmap_page(NULL, sg->dma_address, sg->length, DMA_FROM_DEVICE);

		/* Swap the contents of the buffer */
		buffer = kmap_atomic(sg->page, KM_BIO_SRC_IRQ) + sg->offset;
		pr_debug("buffer = %p, length = %d\n", buffer, sg->length);

		data->bytes_xfered += sg->length;

		if (cpu_is_at91rm9200()) {	/* AT91RM9200 errata */
			int index;

			for (index = 0; index < (sg->length / 4); index++)
				buffer[index] = swab32(buffer[index]);
		}

		kunmap_atomic(buffer, KM_BIO_SRC_IRQ);
		flush_dcache_page(sg->page);
	}

	/* Is there another transfer to trigger? */
	if (host->transfer_index < data->sg_len)
		at91mci_pre_dma_read(host);
	else {
		at91_mci_write(host, AT91_MCI_IER, AT91_MCI_RXBUFF);
		at91_mci_write(host, AT91_PDC_PTCR, AT91_PDC_RXTDIS | AT91_PDC_TXTDIS);
	}

	pr_debug("post dma read done\n");
}

/*
 * Handle transmitted data
 */
static void at91_mci_handle_transmitted(struct at91mci_host *host)
{
	struct mmc_command *cmd;
	struct mmc_data *data;

	pr_debug("Handling the transmit\n");

	/* Disable the transfer */
	at91_mci_write(host, AT91_PDC_PTCR, AT91_PDC_RXTDIS | AT91_PDC_TXTDIS);

	/* Now wait for cmd ready */
	at91_mci_write(host, AT91_MCI_IDR, AT91_MCI_TXBUFE);
	at91_mci_write(host, AT91_MCI_IER, AT91_MCI_NOTBUSY);

	cmd = host->cmd;
	if (!cmd) return;

	data = cmd->data;
	if (!data) return;

	data->bytes_xfered = host->total_length;
}

/*
 * Enable the controller
 */
static void at91_mci_enable(struct at91mci_host *host)
{
	at91_mci_write(host, AT91_MCI_CR, AT91_MCI_MCIEN);
	at91_mci_write(host, AT91_MCI_IDR, 0xffffffff);
	at91_mci_write(host, AT91_MCI_DTOR, AT91_MCI_DTOMUL_1M | AT91_MCI_DTOCYC);
	at91_mci_write(host, AT91_MCI_MR, AT91_MCI_PDCMODE | 0x34a);

	/* use Slot A or B (only one at same time) */
	at91_mci_write(host, AT91_MCI_SDCR, host->board->slot_b);
}

/*
 * Disable the controller
 */
static void at91_mci_disable(struct at91mci_host *host)
{
	at91_mci_write(host, AT91_MCI_CR, AT91_MCI_MCIDIS | AT91_MCI_SWRST);
}

/*
 * Send a command
 * return the interrupts to enable
 */
static unsigned int at91_mci_send_command(struct at91mci_host *host, struct mmc_command *cmd)
{
	unsigned int cmdr, mr;
	unsigned int block_length;
	struct mmc_data *data = cmd->data;

	unsigned int blocks;
	unsigned int ier = 0;

	host->cmd = cmd;

	/* Not sure if this is needed */
#if 0
	if ((at91_mci_read(host, AT91_MCI_SR) & AT91_MCI_RTOE) && (cmd->opcode == 1)) {
		pr_debug("Clearing timeout\n");
		at91_mci_write(host, AT91_MCI_ARGR, 0);
		at91_mci_write(host, AT91_MCI_CMDR, AT91_MCI_OPDCMD);
		while (!(at91_mci_read(host, AT91_MCI_SR) & AT91_MCI_CMDRDY)) {
			/* spin */
			pr_debug("Clearing: SR = %08X\n", at91_mci_read(host, AT91_MCI_SR));
		}
	}
#endif
	cmdr = cmd->opcode;

	if (mmc_resp_type(cmd) == MMC_RSP_NONE)
		cmdr |= AT91_MCI_RSPTYP_NONE;
	else {
		/* if a response is expected then allow maximum response latancy */
		cmdr |= AT91_MCI_MAXLAT;
		/* set 136 bit response for R2, 48 bit response otherwise */
		if (mmc_resp_type(cmd) == MMC_RSP_R2)
			cmdr |= AT91_MCI_RSPTYP_136;
		else
			cmdr |= AT91_MCI_RSPTYP_48;
	}

	if (data) {
		block_length = data->blksz;
		blocks = data->blocks;

		/* always set data start - also set direction flag for read */
		if (data->flags & MMC_DATA_READ)
			cmdr |= (AT91_MCI_TRDIR | AT91_MCI_TRCMD_START);
		else if (data->flags & MMC_DATA_WRITE)
			cmdr |= AT91_MCI_TRCMD_START;

		if (data->flags & MMC_DATA_STREAM)
			cmdr |= AT91_MCI_TRTYP_STREAM;
		if (data->flags & MMC_DATA_MULTI)
			cmdr |= AT91_MCI_TRTYP_MULTIPLE;
	}
	else {
		block_length = 0;
		blocks = 0;
	}

	if (cmd->opcode == MMC_STOP_TRANSMISSION)
		cmdr |= AT91_MCI_TRCMD_STOP;

	if (host->bus_mode == MMC_BUSMODE_OPENDRAIN)
		cmdr |= AT91_MCI_OPDCMD;

	/*
	 * Set the arguments and send the command
	 */
	pr_debug("Sending command %d as %08X, arg = %08X, blocks = %d, length = %d (MR = %08X)\n",
		cmd->opcode, cmdr, cmd->arg, blocks, block_length, at91_mci_read(host, AT91_MCI_MR));

	if (!data) {
		at91_mci_write(host, AT91_PDC_PTCR, AT91_PDC_TXTDIS | AT91_PDC_RXTDIS);
		at91_mci_write(host, AT91_PDC_RPR, 0);
		at91_mci_write(host, AT91_PDC_RCR, 0);
		at91_mci_write(host, AT91_PDC_RNPR, 0);
		at91_mci_write(host, AT91_PDC_RNCR, 0);
		at91_mci_write(host, AT91_PDC_TPR, 0);
		at91_mci_write(host, AT91_PDC_TCR, 0);
		at91_mci_write(host, AT91_PDC_TNPR, 0);
		at91_mci_write(host, AT91_PDC_TNCR, 0);

		at91_mci_write(host, AT91_MCI_ARGR, cmd->arg);
		at91_mci_write(host, AT91_MCI_CMDR, cmdr);
		return AT91_MCI_CMDRDY;
	}

	mr = at91_mci_read(host, AT91_MCI_MR) & 0x7fff;	/* zero block length and PDC mode */
	at91_mci_write(host, AT91_MCI_MR, mr | (block_length << 16) | AT91_MCI_PDCMODE);

	/*
	 * Disable the PDC controller
	 */
	at91_mci_write(host, AT91_PDC_PTCR, AT91_PDC_RXTDIS | AT91_PDC_TXTDIS);

	if (cmdr & AT91_MCI_TRCMD_START) {
		data->bytes_xfered = 0;
		host->transfer_index = 0;
		host->in_use_index = 0;
		if (cmdr & AT91_MCI_TRDIR) {
			/*
			 * Handle a read
			 */
			host->buffer = NULL;
			host->total_length = 0;

			at91mci_pre_dma_read(host);
			ier = AT91_MCI_ENDRX /* | AT91_MCI_RXBUFF */;
		}
		else {
			/*
			 * Handle a write
			 */
			host->total_length = block_length * blocks;
			host->buffer = dma_alloc_coherent(NULL,
						  host->total_length,
						  &host->physical_address, GFP_KERNEL);

			at91mci_sg_to_dma(host, data);

			pr_debug("Transmitting %d bytes\n", host->total_length);

			at91_mci_write(host, AT91_PDC_TPR, host->physical_address);
			at91_mci_write(host, AT91_PDC_TCR, host->total_length / 4);
			ier = AT91_MCI_TXBUFE;
		}
	}

	/*
	 * Send the command and then enable the PDC - not the other way round as
	 * the data sheet says
	 */

	at91_mci_write(host, AT91_MCI_ARGR, cmd->arg);
	at91_mci_write(host, AT91_MCI_CMDR, cmdr);

	if (cmdr & AT91_MCI_TRCMD_START) {
		if (cmdr & AT91_MCI_TRDIR)
			at91_mci_write(host, AT91_PDC_PTCR, AT91_PDC_RXTEN);
		else
			at91_mci_write(host, AT91_PDC_PTCR, AT91_PDC_TXTEN);
	}
	return ier;
}

/*
 * Wait for a command to complete
 */
static void at91mci_process_command(struct at91mci_host *host, struct mmc_command *cmd)
{
	unsigned int ier;

	ier = at91_mci_send_command(host, cmd);

	pr_debug("setting ier to %08X\n", ier);

	/* Stop on errors or the required value */
	at91_mci_write(host, AT91_MCI_IER, AT91_MCI_ERRORS | ier);
}

/*
 * Process the next step in the request
 */
static void at91mci_process_next(struct at91mci_host *host)
{
	if (!(host->flags & FL_SENT_COMMAND)) {
		host->flags |= FL_SENT_COMMAND;
		at91mci_process_command(host, host->request->cmd);
	}
	else if ((!(host->flags & FL_SENT_STOP)) && host->request->stop) {
		host->flags |= FL_SENT_STOP;
		at91mci_process_command(host, host->request->stop);
	}
	else
		mmc_request_done(host->mmc, host->request);
}

/*
 * Handle a command that has been completed
 */
static void at91mci_completed_command(struct at91mci_host *host)
{
	struct mmc_command *cmd = host->cmd;
	unsigned int status;

	at91_mci_write(host, AT91_MCI_IDR, 0xffffffff);

	cmd->resp[0] = at91_mci_read(host, AT91_MCI_RSPR(0));
	cmd->resp[1] = at91_mci_read(host, AT91_MCI_RSPR(1));
	cmd->resp[2] = at91_mci_read(host, AT91_MCI_RSPR(2));
	cmd->resp[3] = at91_mci_read(host, AT91_MCI_RSPR(3));

	if (host->buffer) {
		dma_free_coherent(NULL, host->total_length, host->buffer, host->physical_address);
		host->buffer = NULL;
	}

	status = at91_mci_read(host, AT91_MCI_SR);

	pr_debug("Status = %08X [%08X %08X %08X %08X]\n",
		 status, cmd->resp[0], cmd->resp[1], cmd->resp[2], cmd->resp[3]);

	if (status & (AT91_MCI_RINDE | AT91_MCI_RDIRE | AT91_MCI_RCRCE |
			AT91_MCI_RENDE | AT91_MCI_RTOE | AT91_MCI_DCRCE |
			AT91_MCI_DTOE | AT91_MCI_OVRE | AT91_MCI_UNRE)) {
		if ((status & AT91_MCI_RCRCE) &&
			((cmd->opcode == MMC_SEND_OP_COND) || (cmd->opcode == SD_APP_OP_COND))) {
			cmd->error = MMC_ERR_NONE;
		}
		else {
			if (status & (AT91_MCI_RTOE | AT91_MCI_DTOE))
				cmd->error = MMC_ERR_TIMEOUT;
			else if (status & (AT91_MCI_RCRCE | AT91_MCI_DCRCE))
				cmd->error = MMC_ERR_BADCRC;
			else if (status & (AT91_MCI_OVRE | AT91_MCI_UNRE))
				cmd->error = MMC_ERR_FIFO;
			else
				cmd->error = MMC_ERR_FAILED;

			pr_debug("Error detected and set to %d (cmd = %d, retries = %d)\n",
				 cmd->error, cmd->opcode, cmd->retries);
		}
	}
	else
		cmd->error = MMC_ERR_NONE;

	at91mci_process_next(host);
}

/*
 * Handle an MMC request
 */
static void at91_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
	struct at91mci_host *host = mmc_priv(mmc);
	host->request = mrq;
	host->flags = 0;

	at91mci_process_next(host);
}

/*
 * Set the IOS
 */
static void at91_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
	int clkdiv;
	struct at91mci_host *host = mmc_priv(mmc);
	unsigned long at91_master_clock = clk_get_rate(host->mci_clk);

	host->bus_mode = ios->bus_mode;

	if (ios->clock == 0) {
		/* Disable the MCI controller */
		at91_mci_write(host, AT91_MCI_CR, AT91_MCI_MCIDIS);
		clkdiv = 0;
	}
	else {
		/* Enable the MCI controller */
		at91_mci_write(host, AT91_MCI_CR, AT91_MCI_MCIEN);

		if ((at91_master_clock % (ios->clock * 2)) == 0)
			clkdiv = ((at91_master_clock / ios->clock) / 2) - 1;
		else
			clkdiv = (at91_master_clock / ios->clock) / 2;

		pr_debug("clkdiv = %d. mcck = %ld\n", clkdiv,
			at91_master_clock / (2 * (clkdiv + 1)));
	}
	if (ios->bus_width == MMC_BUS_WIDTH_4 && host->board->wire4) {
		pr_debug("MMC: Setting controller bus width to 4\n");
		at91_mci_write(host, AT91_MCI_SDCR, at91_mci_read(host, AT91_MCI_SDCR) | AT91_MCI_SDCBUS);
	}
	else {
		pr_debug("MMC: Setting controller bus width to 1\n");
		at91_mci_write(host, AT91_MCI_SDCR, at91_mci_read(host, AT91_MCI_SDCR) & ~AT91_MCI_SDCBUS);
	}

	/* Set the clock divider */
	at91_mci_write(host, AT91_MCI_MR, (at91_mci_read(host, AT91_MCI_MR) & ~AT91_MCI_CLKDIV) | clkdiv);

	/* maybe switch power to the card */
	if (host->board->vcc_pin) {
		switch (ios->power_mode) {
			case MMC_POWER_OFF:
				at91_set_gpio_value(host->board->vcc_pin, 0);
				break;
			case MMC_POWER_UP:
			case MMC_POWER_ON:
				at91_set_gpio_value(host->board->vcc_pin, 1);
				break;
		}
	}
}

/*
 * Handle an interrupt
 */
static irqreturn_t at91_mci_irq(int irq, void *devid)
{
	struct at91mci_host *host = devid;
	int completed = 0;
	unsigned int int_status, int_mask;

	int_status = at91_mci_read(host, AT91_MCI_SR);
	int_mask = at91_mci_read(host, AT91_MCI_IMR);
	
	pr_debug("MCI irq: status = %08X, %08X, %08X\n", int_status, int_mask,
		int_status & int_mask);
	
	int_status = int_status & int_mask;

	if (int_status & AT91_MCI_ERRORS) {
		completed = 1;
		
		if (int_status & AT91_MCI_UNRE)
			pr_debug("MMC: Underrun error\n");
		if (int_status & AT91_MCI_OVRE)
			pr_debug("MMC: Overrun error\n");
		if (int_status & AT91_MCI_DTOE)
			pr_debug("MMC: Data timeout\n");
		if (int_status & AT91_MCI_DCRCE)
			pr_debug("MMC: CRC error in data\n");
		if (int_status & AT91_MCI_RTOE)
			pr_debug("MMC: Response timeout\n");
		if (int_status & AT91_MCI_RENDE)
			pr_debug("MMC: Response end bit error\n");
		if (int_status & AT91_MCI_RCRCE)
			pr_debug("MMC: Response CRC error\n");
		if (int_status & AT91_MCI_RDIRE)
			pr_debug("MMC: Response direction error\n");
		if (int_status & AT91_MCI_RINDE)
			pr_debug("MMC: Response index error\n");
	} else {
		/* Only continue processing if no errors */

		if (int_status & AT91_MCI_TXBUFE) {
			pr_debug("TX buffer empty\n");
			at91_mci_handle_transmitted(host);
		}

		if (int_status & AT91_MCI_RXBUFF) {
			pr_debug("RX buffer full\n");
			at91_mci_write(host, AT91_MCI_IER, AT91_MCI_CMDRDY);
		}

		if (int_status & AT91_MCI_ENDTX)
			pr_debug("Transmit has ended\n");

		if (int_status & AT91_MCI_ENDRX) {
			pr_debug("Receive has ended\n");
			at91mci_post_dma_read(host);
		}

		if (int_status & AT91_MCI_NOTBUSY) {
			pr_debug("Card is ready\n");
			at91_mci_write(host, AT91_MCI_IER, AT91_MCI_CMDRDY);
		}

		if (int_status & AT91_MCI_DTIP)
			pr_debug("Data transfer in progress\n");

		if (int_status & AT91_MCI_BLKE)
			pr_debug("Block transfer has ended\n");

		if (int_status & AT91_MCI_TXRDY)
			pr_debug("Ready to transmit\n");

		if (int_status & AT91_MCI_RXRDY)
			pr_debug("Ready to receive\n");

		if (int_status & AT91_MCI_CMDRDY) {
			pr_debug("Command ready\n");
			completed = 1;
		}
	}

	if (completed) {
		pr_debug("Completed command\n");
		at91_mci_write(host, AT91_MCI_IDR, 0xffffffff);
		at91mci_completed_command(host);
	} else
		at91_mci_write(host, AT91_MCI_IDR, int_status);

	return IRQ_HANDLED;
}

static irqreturn_t at91_mmc_det_irq(int irq, void *_host)
{
	struct at91mci_host *host = _host;
	int present = !at91_get_gpio_value(irq);

	/*
	 * we expect this irq on both insert and remove,
	 * and use a short delay to debounce.
	 */
	if (present != host->present) {
		host->present = present;
		pr_debug("%s: card %s\n", mmc_hostname(host->mmc),
			present ? "insert" : "remove");
		if (!present) {
			pr_debug("****** Resetting SD-card bus width ******\n");
			at91_mci_write(host, AT91_MCI_SDCR, at91_mci_read(host, AT91_MCI_SDCR) & ~AT91_MCI_SDCBUS);
		}
		mmc_detect_change(host->mmc, msecs_to_jiffies(100));
	}
	return IRQ_HANDLED;
}

int at91_mci_get_ro(struct mmc_host *mmc)
{
	int read_only = 0;
	struct at91mci_host *host = mmc_priv(mmc);

	if (host->board->wp_pin) {
		read_only = at91_get_gpio_value(host->board->wp_pin);
		printk(KERN_WARNING "%s: card is %s\n", mmc_hostname(mmc),
				(read_only ? "read-only" : "read-write") );
	}
	else {
		printk(KERN_WARNING "%s: host does not support reading read-only "
				"switch.  Assuming write-enable.\n", mmc_hostname(mmc));
	}
	return read_only;
}

static const struct mmc_host_ops at91_mci_ops = {
	.request	= at91_mci_request,
	.set_ios	= at91_mci_set_ios,
	.get_ro		= at91_mci_get_ro,
};

/*
 * Probe for the device
 */
static int at91_mci_probe(struct platform_device *pdev)
{
	struct mmc_host *mmc;
	struct at91mci_host *host;
	struct resource *res;
	int ret;

	pr_debug("Probe MCI devices\n");

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENXIO;

	if (!request_mem_region(res->start, res->end - res->start + 1, DRIVER_NAME))
		return -EBUSY;

	mmc = mmc_alloc_host(sizeof(struct at91mci_host), &pdev->dev);
	if (!mmc) {
		pr_debug("Failed to allocate mmc host\n");
		release_mem_region(res->start, res->end - res->start + 1);
		return -ENOMEM;
	}

	mmc->ops = &at91_mci_ops;
	mmc->f_min = 375000;
	mmc->f_max = 25000000;
	mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
	mmc->caps = MMC_CAP_BYTEBLOCK;

	host = mmc_priv(mmc);
	host->mmc = mmc;
	host->buffer = NULL;
	host->bus_mode = 0;
	host->board = pdev->dev.platform_data;
	if (host->board->wire4) {
#ifdef SUPPORT_4WIRE
		mmc->caps |= MMC_CAP_4_BIT_DATA;
#else
		printk("AT91 MMC: 4 wire bus mode not supported by this driver - using 1 wire\n");
#endif
	}

	/*
	 * Get Clock
	 */
	host->mci_clk = clk_get(&pdev->dev, "mci_clk");
	if (IS_ERR(host->mci_clk)) {
		printk(KERN_ERR "AT91 MMC: no clock defined.\n");
		mmc_free_host(mmc);
		release_mem_region(res->start, res->end - res->start + 1);
		return -ENODEV;
	}

	/*
	 * Map I/O region
	 */
	host->baseaddr = ioremap(res->start, res->end - res->start + 1);
	if (!host->baseaddr) {
		clk_put(host->mci_clk);
		mmc_free_host(mmc);
		release_mem_region(res->start, res->end - res->start + 1);
		return -ENOMEM;
	}

	/*
	 * Reset hardware
	 */
	clk_enable(host->mci_clk);		/* Enable the peripheral clock */
	at91_mci_disable(host);
	at91_mci_enable(host);

	/*
	 * Allocate the MCI interrupt
	 */
	host->irq = platform_get_irq(pdev, 0);
	ret = request_irq(host->irq, at91_mci_irq, IRQF_SHARED, DRIVER_NAME, host);
	if (ret) {
		printk(KERN_ERR "AT91 MMC: Failed to request MCI interrupt\n");
		clk_disable(host->mci_clk);
		clk_put(host->mci_clk);
		mmc_free_host(mmc);
		iounmap(host->baseaddr);
		release_mem_region(res->start, res->end - res->start + 1);
		return ret;
	}

	platform_set_drvdata(pdev, mmc);

	/*
	 * Add host to MMC layer
	 */
	if (host->board->det_pin)
		host->present = !at91_get_gpio_value(host->board->det_pin);
	else
		host->present = -1;

	mmc_add_host(mmc);

	/*
	 * monitor card insertion/removal if we can
	 */
	if (host->board->det_pin) {
		ret = request_irq(host->board->det_pin, at91_mmc_det_irq,
				0, DRIVER_NAME, host);
		if (ret)
			printk(KERN_ERR "AT91 MMC: Couldn't allocate MMC detect irq\n");
	}

	pr_debug("Added MCI driver\n");

	return 0;
}

/*
 * Remove a device
 */
static int at91_mci_remove(struct platform_device *pdev)
{
	struct mmc_host *mmc = platform_get_drvdata(pdev);
	struct at91mci_host *host;
	struct resource *res;

	if (!mmc)
		return -1;

	host = mmc_priv(mmc);

	if (host->present != -1) {
		free_irq(host->board->det_pin, host);
		cancel_delayed_work(&host->mmc->detect);
	}

	at91_mci_disable(host);
	mmc_remove_host(mmc);
	free_irq(host->irq, host);

	clk_disable(host->mci_clk);			/* Disable the peripheral clock */
	clk_put(host->mci_clk);

	iounmap(host->baseaddr);
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(res->start, res->end - res->start + 1);

	mmc_free_host(mmc);
	platform_set_drvdata(pdev, NULL);
	pr_debug("MCI Removed\n");

	return 0;
}

#ifdef CONFIG_PM
static int at91_mci_suspend(struct platform_device *pdev, pm_message_t state)
{
	struct mmc_host *mmc = platform_get_drvdata(pdev);
	int ret = 0;

	if (mmc)
		ret = mmc_suspend_host(mmc, state);

	return ret;
}

static int at91_mci_resume(struct platform_device *pdev)
{
	struct mmc_host *mmc = platform_get_drvdata(pdev);
	int ret = 0;

	if (mmc)
		ret = mmc_resume_host(mmc);

	return ret;
}
#else
#define at91_mci_suspend	NULL
#define at91_mci_resume		NULL
#endif

static struct platform_driver at91_mci_driver = {
	.probe		= at91_mci_probe,
	.remove		= at91_mci_remove,
	.suspend	= at91_mci_suspend,
	.resume		= at91_mci_resume,
	.driver		= {
		.name	= DRIVER_NAME,
		.owner	= THIS_MODULE,
	},
};

static int __init at91_mci_init(void)
{
	return platform_driver_register(&at91_mci_driver);
}

static void __exit at91_mci_exit(void)
{
	platform_driver_unregister(&at91_mci_driver);
}

module_init(at91_mci_init);
module_exit(at91_mci_exit);

MODULE_DESCRIPTION("AT91 Multimedia Card Interface driver");
MODULE_AUTHOR("Nick Randell");
MODULE_LICENSE("GPL");