aboutsummaryrefslogtreecommitdiff
path: root/drivers/block/mg_disk.c
blob: 6440d59454140bbd5e5b04d09e9a5c13c76dfb8a (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
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
/*
 *  drivers/block/mg_disk.c
 *
 *  Support for the mGine m[g]flash IO mode.
 *  Based on legacy hd.c
 *
 * (c) 2008 mGine Co.,LTD
 * (c) 2008 unsik Kim <donari75@gmail.com>
 *
 *  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/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/hdreg.h>
#include <linux/ata.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/mg_disk.h>

#define MG_RES_SEC (CONFIG_MG_DISK_RES << 1)

/* name for block device */
#define MG_DISK_NAME "mgd"

#define MG_DISK_MAJ 0
#define MG_DISK_MAX_PART 16
#define MG_SECTOR_SIZE 512
#define MG_MAX_SECTS 256

/* Register offsets */
#define MG_BUFF_OFFSET			0x8000
#define MG_STORAGE_BUFFER_SIZE		0x200
#define MG_REG_OFFSET			0xC000
#define MG_REG_FEATURE			(MG_REG_OFFSET + 2)	/* write case */
#define MG_REG_ERROR			(MG_REG_OFFSET + 2)	/* read case */
#define MG_REG_SECT_CNT			(MG_REG_OFFSET + 4)
#define MG_REG_SECT_NUM			(MG_REG_OFFSET + 6)
#define MG_REG_CYL_LOW			(MG_REG_OFFSET + 8)
#define MG_REG_CYL_HIGH			(MG_REG_OFFSET + 0xA)
#define MG_REG_DRV_HEAD			(MG_REG_OFFSET + 0xC)
#define MG_REG_COMMAND			(MG_REG_OFFSET + 0xE)	/* write case */
#define MG_REG_STATUS			(MG_REG_OFFSET + 0xE)	/* read  case */
#define MG_REG_DRV_CTRL			(MG_REG_OFFSET + 0x10)
#define MG_REG_BURST_CTRL		(MG_REG_OFFSET + 0x12)

/* handy status */
#define MG_STAT_READY	(ATA_DRDY | ATA_DSC)
#define MG_READY_OK(s)	(((s) & (MG_STAT_READY | (ATA_BUSY | ATA_DF | \
				 ATA_ERR))) == MG_STAT_READY)

/* error code for others */
#define MG_ERR_NONE		0
#define MG_ERR_TIMEOUT		0x100
#define MG_ERR_INIT_STAT	0x101
#define MG_ERR_TRANSLATION	0x102
#define MG_ERR_CTRL_RST		0x103
#define MG_ERR_INV_STAT		0x104
#define MG_ERR_RSTOUT		0x105

#define MG_MAX_ERRORS	6	/* Max read/write errors */

/* command */
#define MG_CMD_RD 0x20
#define MG_CMD_WR 0x30
#define MG_CMD_SLEEP 0x99
#define MG_CMD_WAKEUP 0xC3
#define MG_CMD_ID 0xEC
#define MG_CMD_WR_CONF 0x3C
#define MG_CMD_RD_CONF 0x40

/* operation mode */
#define MG_OP_CASCADE (1 << 0)
#define MG_OP_CASCADE_SYNC_RD (1 << 1)
#define MG_OP_CASCADE_SYNC_WR (1 << 2)
#define MG_OP_INTERLEAVE (1 << 3)

/* synchronous */
#define MG_BURST_LAT_4 (3 << 4)
#define MG_BURST_LAT_5 (4 << 4)
#define MG_BURST_LAT_6 (5 << 4)
#define MG_BURST_LAT_7 (6 << 4)
#define MG_BURST_LAT_8 (7 << 4)
#define MG_BURST_LEN_4 (1 << 1)
#define MG_BURST_LEN_8 (2 << 1)
#define MG_BURST_LEN_16 (3 << 1)
#define MG_BURST_LEN_32 (4 << 1)
#define MG_BURST_LEN_CONT (0 << 1)

/* timeout value (unit: ms) */
#define MG_TMAX_CONF_TO_CMD	1
#define MG_TMAX_WAIT_RD_DRQ	10
#define MG_TMAX_WAIT_WR_DRQ	500
#define MG_TMAX_RST_TO_BUSY	10
#define MG_TMAX_HDRST_TO_RDY	500
#define MG_TMAX_SWRST_TO_RDY	500
#define MG_TMAX_RSTOUT		3000

#define MG_DEV_MASK (MG_BOOT_DEV | MG_STORAGE_DEV | MG_STORAGE_DEV_SKIP_RST)

/* main structure for mflash driver */
struct mg_host {
	struct device *dev;

	struct request_queue *breq;
	struct request *req;
	spinlock_t lock;
	struct gendisk *gd;

	struct timer_list timer;
	void (*mg_do_intr) (struct mg_host *);

	u16 id[ATA_ID_WORDS];

	u16 cyls;
	u16 heads;
	u16 sectors;
	u32 n_sectors;
	u32 nres_sectors;

	void __iomem *dev_base;
	unsigned int irq;
	unsigned int rst;
	unsigned int rstout;

	u32 major;
	u32 error;
};

/*
 * Debugging macro and defines
 */
#undef DO_MG_DEBUG
#ifdef DO_MG_DEBUG
#  define MG_DBG(fmt, args...) \
	printk(KERN_DEBUG "%s:%d "fmt, __func__, __LINE__, ##args)
#else /* CONFIG_MG_DEBUG */
#  define MG_DBG(fmt, args...) do { } while (0)
#endif /* CONFIG_MG_DEBUG */

static void mg_request(struct request_queue *);

static bool mg_end_request(struct mg_host *host, int err, unsigned int nr_bytes)
{
	if (__blk_end_request(host->req, err, nr_bytes))
		return true;

	host->req = NULL;
	return false;
}

static bool mg_end_request_cur(struct mg_host *host, int err)
{
	return mg_end_request(host, err, blk_rq_cur_bytes(host->req));
}

static void mg_dump_status(const char *msg, unsigned int stat,
		struct mg_host *host)
{
	char *name = MG_DISK_NAME;

	if (host->req)
		name = host->req->rq_disk->disk_name;

	printk(KERN_ERR "%s: %s: status=0x%02x { ", name, msg, stat & 0xff);
	if (stat & ATA_BUSY)
		printk("Busy ");
	if (stat & ATA_DRDY)
		printk("DriveReady ");
	if (stat & ATA_DF)
		printk("WriteFault ");
	if (stat & ATA_DSC)
		printk("SeekComplete ");
	if (stat & ATA_DRQ)
		printk("DataRequest ");
	if (stat & ATA_CORR)
		printk("CorrectedError ");
	if (stat & ATA_ERR)
		printk("Error ");
	printk("}\n");
	if ((stat & ATA_ERR) == 0) {
		host->error = 0;
	} else {
		host->error = inb((unsigned long)host->dev_base + MG_REG_ERROR);
		printk(KERN_ERR "%s: %s: error=0x%02x { ", name, msg,
				host->error & 0xff);
		if (host->error & ATA_BBK)
			printk("BadSector ");
		if (host->error & ATA_UNC)
			printk("UncorrectableError ");
		if (host->error & ATA_IDNF)
			printk("SectorIdNotFound ");
		if (host->error & ATA_ABORTED)
			printk("DriveStatusError ");
		if (host->error & ATA_AMNF)
			printk("AddrMarkNotFound ");
		printk("}");
		if (host->error & (ATA_BBK | ATA_UNC | ATA_IDNF | ATA_AMNF)) {
			if (host->req)
				printk(", sector=%u",
				       (unsigned int)blk_rq_pos(host->req));
		}
		printk("\n");
	}
}

static unsigned int mg_wait(struct mg_host *host, u32 expect, u32 msec)
{
	u8 status;
	unsigned long expire, cur_jiffies;
	struct mg_drv_data *prv_data = host->dev->platform_data;

	host->error = MG_ERR_NONE;
	expire = jiffies + msecs_to_jiffies(msec);

	/* These 2 times dummy status read prevents reading invalid
	 * status. A very little time (3 times of mflash operating clk)
	 * is required for busy bit is set. Use dummy read instead of
	 * busy wait, because mflash's PLL is machine dependent.
	 */
	if (prv_data->use_polling) {
		status = inb((unsigned long)host->dev_base + MG_REG_STATUS);
		status = inb((unsigned long)host->dev_base + MG_REG_STATUS);
	}

	status = inb((unsigned long)host->dev_base + MG_REG_STATUS);

	do {
		cur_jiffies = jiffies;
		if (status & ATA_BUSY) {
			if (expect == ATA_BUSY)
				break;
		} else {
			/* Check the error condition! */
			if (status & ATA_ERR) {
				mg_dump_status("mg_wait", status, host);
				break;
			}

			if (expect == MG_STAT_READY)
				if (MG_READY_OK(status))
					break;

			if (expect == ATA_DRQ)
				if (status & ATA_DRQ)
					break;
		}
		if (!msec) {
			mg_dump_status("not ready", status, host);
			return MG_ERR_INV_STAT;
		}

		status = inb((unsigned long)host->dev_base + MG_REG_STATUS);
	} while (time_before(cur_jiffies, expire));

	if (time_after_eq(cur_jiffies, expire) && msec)
		host->error = MG_ERR_TIMEOUT;

	return host->error;
}

static unsigned int mg_wait_rstout(u32 rstout, u32 msec)
{
	unsigned long expire;

	expire = jiffies + msecs_to_jiffies(msec);
	while (time_before(jiffies, expire)) {
		if (gpio_get_value(rstout) == 1)
			return MG_ERR_NONE;
		msleep(10);
	}

	return MG_ERR_RSTOUT;
}

static void mg_unexpected_intr(struct mg_host *host)
{
	u32 status = inb((unsigned long)host->dev_base + MG_REG_STATUS);

	mg_dump_status("mg_unexpected_intr", status, host);
}

static irqreturn_t mg_irq(int irq, void *dev_id)
{
	struct mg_host *host = dev_id;
	void (*handler)(struct mg_host *) = host->mg_do_intr;

	spin_lock(&host->lock);

	host->mg_do_intr = NULL;
	del_timer(&host->timer);
	if (!handler)
		handler = mg_unexpected_intr;
	handler(host);

	spin_unlock(&host->lock);

	return IRQ_HANDLED;
}

/* local copy of ata_id_string() */
static void mg_id_string(const u16 *id, unsigned char *s,
			 unsigned int ofs, unsigned int len)
{
	unsigned int c;

	BUG_ON(len & 1);

	while (len > 0) {
		c = id[ofs] >> 8;
		*s = c;
		s++;

		c = id[ofs] & 0xff;
		*s = c;
		s++;

		ofs++;
		len -= 2;
	}
}

/* local copy of ata_id_c_string() */
static void mg_id_c_string(const u16 *id, unsigned char *s,
			   unsigned int ofs, unsigned int len)
{
	unsigned char *p;

	mg_id_string(id, s, ofs, len - 1);

	p = s + strnlen(s, len - 1);
	while (p > s && p[-1] == ' ')
		p--;
	*p = '\0';
}

static int mg_get_disk_id(struct mg_host *host)
{
	u32 i;
	s32 err;
	const u16 *id = host->id;
	struct mg_drv_data *prv_data = host->dev->platform_data;
	char fwrev[ATA_ID_FW_REV_LEN + 1];
	char model[ATA_ID_PROD_LEN + 1];
	char serial[ATA_ID_SERNO_LEN + 1];

	if (!prv_data->use_polling)
		outb(ATA_NIEN, (unsigned long)host->dev_base + MG_REG_DRV_CTRL);

	outb(MG_CMD_ID, (unsigned long)host->dev_base + MG_REG_COMMAND);
	err = mg_wait(host, ATA_DRQ, MG_TMAX_WAIT_RD_DRQ);
	if (err)
		return err;

	for (i = 0; i < (MG_SECTOR_SIZE >> 1); i++)
		host->id[i] = le16_to_cpu(inw((unsigned long)host->dev_base +
					MG_BUFF_OFFSET + i * 2));

	outb(MG_CMD_RD_CONF, (unsigned long)host->dev_base + MG_REG_COMMAND);
	err = mg_wait(host, MG_STAT_READY, MG_TMAX_CONF_TO_CMD);
	if (err)
		return err;

	if ((id[ATA_ID_FIELD_VALID] & 1) == 0)
		return MG_ERR_TRANSLATION;

	host->n_sectors = ata_id_u32(id, ATA_ID_LBA_CAPACITY);
	host->cyls = id[ATA_ID_CYLS];
	host->heads = id[ATA_ID_HEADS];
	host->sectors = id[ATA_ID_SECTORS];

	if (MG_RES_SEC && host->heads && host->sectors) {
		/* modify cyls, n_sectors */
		host->cyls = (host->n_sectors - MG_RES_SEC) /
			host->heads / host->sectors;
		host->nres_sectors = host->n_sectors - host->cyls *
			host->heads * host->sectors;
		host->n_sectors -= host->nres_sectors;
	}

	mg_id_c_string(id, fwrev, ATA_ID_FW_REV, sizeof(fwrev));
	mg_id_c_string(id, model, ATA_ID_PROD, sizeof(model));
	mg_id_c_string(id, serial, ATA_ID_SERNO, sizeof(serial));
	printk(KERN_INFO "mg_disk: model: %s\n", model);
	printk(KERN_INFO "mg_disk: firm: %.8s\n", fwrev);
	printk(KERN_INFO "mg_disk: serial: %s\n", serial);
	printk(KERN_INFO "mg_disk: %d + reserved %d sectors\n",
			host->n_sectors, host->nres_sectors);

	if (!prv_data->use_polling)
		outb(0, (unsigned long)host->dev_base + MG_REG_DRV_CTRL);

	return err;
}


static int mg_disk_init(struct mg_host *host)
{
	struct mg_drv_data *prv_data = host->dev->platform_data;
	s32 err;
	u8 init_status;

	/* hdd rst low */
	gpio_set_value(host->rst, 0);
	err = mg_wait(host, ATA_BUSY, MG_TMAX_RST_TO_BUSY);
	if (err)
		return err;

	/* hdd rst high */
	gpio_set_value(host->rst, 1);
	err = mg_wait(host, MG_STAT_READY, MG_TMAX_HDRST_TO_RDY);
	if (err)
		return err;

	/* soft reset on */
	outb(ATA_SRST | (prv_data->use_polling ? ATA_NIEN : 0),
			(unsigned long)host->dev_base + MG_REG_DRV_CTRL);
	err = mg_wait(host, ATA_BUSY, MG_TMAX_RST_TO_BUSY);
	if (err)
		return err;

	/* soft reset off */
	outb(prv_data->use_polling ? ATA_NIEN : 0,
			(unsigned long)host->dev_base + MG_REG_DRV_CTRL);
	err = mg_wait(host, MG_STAT_READY, MG_TMAX_SWRST_TO_RDY);
	if (err)
		return err;

	init_status = inb((unsigned long)host->dev_base + MG_REG_STATUS) & 0xf;

	if (init_status == 0xf)
		return MG_ERR_INIT_STAT;

	return err;
}

static void mg_bad_rw_intr(struct mg_host *host)
{
	if (host->req)
		if (++host->req->errors >= MG_MAX_ERRORS ||
		    host->error == MG_ERR_TIMEOUT)
			mg_end_request_cur(host, -EIO);
}

static unsigned int mg_out(struct mg_host *host,
		unsigned int sect_num,
		unsigned int sect_cnt,
		unsigned int cmd,
		void (*intr_addr)(struct mg_host *))
{
	struct mg_drv_data *prv_data = host->dev->platform_data;

	if (mg_wait(host, MG_STAT_READY, MG_TMAX_CONF_TO_CMD))
		return host->error;

	if (!prv_data->use_polling) {
		host->mg_do_intr = intr_addr;
		mod_timer(&host->timer, jiffies + 3 * HZ);
	}
	if (MG_RES_SEC)
		sect_num += MG_RES_SEC;
	outb((u8)sect_cnt, (unsigned long)host->dev_base + MG_REG_SECT_CNT);
	outb((u8)sect_num, (unsigned long)host->dev_base + MG_REG_SECT_NUM);
	outb((u8)(sect_num >> 8), (unsigned long)host->dev_base +
			MG_REG_CYL_LOW);
	outb((u8)(sect_num >> 16), (unsigned long)host->dev_base +
			MG_REG_CYL_HIGH);
	outb((u8)((sect_num >> 24) | ATA_LBA | ATA_DEVICE_OBS),
			(unsigned long)host->dev_base + MG_REG_DRV_HEAD);
	outb(cmd, (unsigned long)host->dev_base + MG_REG_COMMAND);
	return MG_ERR_NONE;
}

static void mg_read(struct request *req)
{
	u32 j;
	struct mg_host *host = req->rq_disk->private_data;

	if (mg_out(host, blk_rq_pos(req), blk_rq_sectors(req),
		   MG_CMD_RD, NULL) != MG_ERR_NONE)
		mg_bad_rw_intr(host);

	MG_DBG("requested %d sects (from %ld), buffer=0x%p\n",
	       blk_rq_sectors(req), blk_rq_pos(req), req->buffer);

	do {
		u16 *buff = (u16 *)req->buffer;

		if (mg_wait(host, ATA_DRQ,
			    MG_TMAX_WAIT_RD_DRQ) != MG_ERR_NONE) {
			mg_bad_rw_intr(host);
			return;
		}
		for (j = 0; j < MG_SECTOR_SIZE >> 1; j++)
			*buff++ = inw((unsigned long)host->dev_base +
				      MG_BUFF_OFFSET + (j << 1));

		outb(MG_CMD_RD_CONF, (unsigned long)host->dev_base +
				MG_REG_COMMAND);
	} while (mg_end_request(host, 0, MG_SECTOR_SIZE));
}

static void mg_write(struct request *req)
{
	u32 j;
	struct mg_host *host = req->rq_disk->private_data;

	if (mg_out(host, blk_rq_pos(req), blk_rq_sectors(req),
		   MG_CMD_WR, NULL) != MG_ERR_NONE) {
		mg_bad_rw_intr(host);
		return;
	}

	MG_DBG("requested %d sects (from %ld), buffer=0x%p\n",
	       blk_rq_sectors(req), blk_rq_pos(req), req->buffer);

	do {
		u16 *buff = (u16 *)req->buffer;

	if (mg_wait(host, ATA_DRQ, MG_TMAX_WAIT_WR_DRQ) != MG_ERR_NONE) {
			mg_bad_rw_intr(host);
			return;
		}
		for (j = 0; j < MG_SECTOR_SIZE >> 1; j++)
			outw(*buff++, (unsigned long)host->dev_base +
				      MG_BUFF_OFFSET + (j << 1));

		outb(MG_CMD_WR_CONF, (unsigned long)host->dev_base +
				MG_REG_COMMAND);
	} while (mg_end_request(host, 0, MG_SECTOR_SIZE));
}

static void mg_read_intr(struct mg_host *host)
{
	struct request *req = host->req;
	u32 i;
	u16 *buff;

	/* check status */
	do {
		i = inb((unsigned long)host->dev_base + MG_REG_STATUS);
		if (i & ATA_BUSY)
			break;
		if (!MG_READY_OK(i))
			break;
		if (i & ATA_DRQ)
			goto ok_to_read;
	} while (0);
	mg_dump_status("mg_read_intr", i, host);
	mg_bad_rw_intr(host);
	mg_request(host->breq);
	return;

ok_to_read:
	/* get current segment of request */
	buff = (u16 *)req->buffer;

	/* read 1 sector */
	for (i = 0; i < MG_SECTOR_SIZE >> 1; i++)
		*buff++ = inw((unsigned long)host->dev_base + MG_BUFF_OFFSET +
			      (i << 1));

	MG_DBG("sector %ld, remaining=%ld, buffer=0x%p\n",
	       blk_rq_pos(req), blk_rq_sectors(req) - 1, req->buffer);

	/* send read confirm */
	outb(MG_CMD_RD_CONF, (unsigned long)host->dev_base + MG_REG_COMMAND);

	if (mg_end_request(host, 0, MG_SECTOR_SIZE)) {
		/* set handler if read remains */
		host->mg_do_intr = mg_read_intr;
		mod_timer(&host->timer, jiffies + 3 * HZ);
	} else /* goto next request */
		mg_request(host->breq);
}

static void mg_write_intr(struct mg_host *host)
{
	struct request *req = host->req;
	u32 i, j;
	u16 *buff;
	bool rem;

	/* check status */
	do {
		i = inb((unsigned long)host->dev_base + MG_REG_STATUS);
		if (i & ATA_BUSY)
			break;
		if (!MG_READY_OK(i))
			break;
		if ((blk_rq_sectors(req) <= 1) || (i & ATA_DRQ))
			goto ok_to_write;
	} while (0);
	mg_dump_status("mg_write_intr", i, host);
	mg_bad_rw_intr(host);
	mg_request(host->breq);
	return;

ok_to_write:
	if ((rem = mg_end_request(host, 0, MG_SECTOR_SIZE))) {
		/* write 1 sector and set handler if remains */
		buff = (u16 *)req->buffer;
		for (j = 0; j < MG_STORAGE_BUFFER_SIZE >> 1; j++) {
			outw(*buff, (unsigned long)host->dev_base +
					MG_BUFF_OFFSET + (j << 1));
			buff++;
		}
		MG_DBG("sector %ld, remaining=%ld, buffer=0x%p\n",
		       blk_rq_pos(req), blk_rq_sectors(req), req->buffer);
		host->mg_do_intr = mg_write_intr;
		mod_timer(&host->timer, jiffies + 3 * HZ);
	}

	/* send write confirm */
	outb(MG_CMD_WR_CONF, (unsigned long)host->dev_base + MG_REG_COMMAND);

	if (!rem)
		mg_request(host->breq);
}

void mg_times_out(unsigned long data)
{
	struct mg_host *host = (struct mg_host *)data;
	char *name;

	spin_lock_irq(&host->lock);

	if (!host->req)
		goto out_unlock;

	host->mg_do_intr = NULL;

	name = host->req->rq_disk->disk_name;
	printk(KERN_DEBUG "%s: timeout\n", name);

	host->error = MG_ERR_TIMEOUT;
	mg_bad_rw_intr(host);

out_unlock:
	mg_request(host->breq);
	spin_unlock_irq(&host->lock);
}

static void mg_request_poll(struct request_queue *q)
{
	struct mg_host *host = q->queuedata;

	while (1) {
		if (!host->req) {
			host->req = blk_fetch_request(q);
			if (!host->req)
				break;
		}

		if (unlikely(!blk_fs_request(host->req))) {
			mg_end_request_cur(host, -EIO);
			continue;
		}

		if (rq_data_dir(host->req) == READ)
			mg_read(host->req);
		else
			mg_write(host->req);
	}
}

static unsigned int mg_issue_req(struct request *req,
		struct mg_host *host,
		unsigned int sect_num,
		unsigned int sect_cnt)
{
	u16 *buff;
	u32 i;

	switch (rq_data_dir(req)) {
	case READ:
		if (mg_out(host, sect_num, sect_cnt, MG_CMD_RD, &mg_read_intr)
				!= MG_ERR_NONE) {
			mg_bad_rw_intr(host);
			return host->error;
		}
		break;
	case WRITE:
		/* TODO : handler */
		outb(ATA_NIEN, (unsigned long)host->dev_base + MG_REG_DRV_CTRL);
		if (mg_out(host, sect_num, sect_cnt, MG_CMD_WR, &mg_write_intr)
				!= MG_ERR_NONE) {
			mg_bad_rw_intr(host);
			return host->error;
		}
		del_timer(&host->timer);
		mg_wait(host, ATA_DRQ, MG_TMAX_WAIT_WR_DRQ);
		outb(0, (unsigned long)host->dev_base + MG_REG_DRV_CTRL);
		if (host->error) {
			mg_bad_rw_intr(host);
			return host->error;
		}
		buff = (u16 *)req->buffer;
		for (i = 0; i < MG_SECTOR_SIZE >> 1; i++) {
			outw(*buff, (unsigned long)host->dev_base +
					MG_BUFF_OFFSET + (i << 1));
			buff++;
		}
		mod_timer(&host->timer, jiffies + 3 * HZ);
		outb(MG_CMD_WR_CONF, (unsigned long)host->dev_base +
				MG_REG_COMMAND);
		break;
	}
	return MG_ERR_NONE;
}

/* This function also called from IRQ context */
static void mg_request(struct request_queue *q)
{
	struct mg_host *host = q->queuedata;
	struct request *req;
	u32 sect_num, sect_cnt;

	while (1) {
		if (!host->req) {
			host->req = blk_fetch_request(q);
			if (!host->req)
				break;
		}
		req = host->req;

		/* check unwanted request call */
		if (host->mg_do_intr)
			return;

		del_timer(&host->timer);

		sect_num = blk_rq_pos(req);
		/* deal whole segments */
		sect_cnt = blk_rq_sectors(req);

		/* sanity check */
		if (sect_num >= get_capacity(req->rq_disk) ||
				((sect_num + sect_cnt) >
				 get_capacity(req->rq_disk))) {
			printk(KERN_WARNING
					"%s: bad access: sector=%d, count=%d\n",
					req->rq_disk->disk_name,
					sect_num, sect_cnt);
			mg_end_request_cur(host, -EIO);
			continue;
		}

		if (unlikely(!blk_fs_request(req))) {
			mg_end_request_cur(host, -EIO);
			continue;
		}

		if (!mg_issue_req(req, host, sect_num, sect_cnt))
			return;
	}
}

static int mg_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
	struct mg_host *host = bdev->bd_disk->private_data;

	geo->cylinders = (unsigned short)host->cyls;
	geo->heads = (unsigned char)host->heads;
	geo->sectors = (unsigned char)host->sectors;
	return 0;
}

static struct block_device_operations mg_disk_ops = {
	.getgeo = mg_getgeo
};

static int mg_suspend(struct platform_device *plat_dev, pm_message_t state)
{
	struct mg_drv_data *prv_data = plat_dev->dev.platform_data;
	struct mg_host *host = prv_data->host;

	if (mg_wait(host, MG_STAT_READY, MG_TMAX_CONF_TO_CMD))
		return -EIO;

	if (!prv_data->use_polling)
		outb(ATA_NIEN, (unsigned long)host->dev_base + MG_REG_DRV_CTRL);

	outb(MG_CMD_SLEEP, (unsigned long)host->dev_base + MG_REG_COMMAND);
	/* wait until mflash deep sleep */
	msleep(1);

	if (mg_wait(host, MG_STAT_READY, MG_TMAX_CONF_TO_CMD)) {
		if (!prv_data->use_polling)
			outb(0, (unsigned long)host->dev_base + MG_REG_DRV_CTRL);
		return -EIO;
	}

	return 0;
}

static int mg_resume(struct platform_device *plat_dev)
{
	struct mg_drv_data *prv_data = plat_dev->dev.platform_data;
	struct mg_host *host = prv_data->host;

	if (mg_wait(host, MG_STAT_READY, MG_TMAX_CONF_TO_CMD))
		return -EIO;

	outb(MG_CMD_WAKEUP, (unsigned long)host->dev_base + MG_REG_COMMAND);
	/* wait until mflash wakeup */
	msleep(1);

	if (mg_wait(host, MG_STAT_READY, MG_TMAX_CONF_TO_CMD))
		return -EIO;

	if (!prv_data->use_polling)
		outb(0, (unsigned long)host->dev_base + MG_REG_DRV_CTRL);

	return 0;
}

static int mg_probe(struct platform_device *plat_dev)
{
	struct mg_host *host;
	struct resource *rsc;
	struct mg_drv_data *prv_data = plat_dev->dev.platform_data;
	int err = 0;

	if (!prv_data) {
		printk(KERN_ERR	"%s:%d fail (no driver_data)\n",
				__func__, __LINE__);
		err = -EINVAL;
		goto probe_err;
	}

	/* alloc mg_host */
	host = kzalloc(sizeof(struct mg_host), GFP_KERNEL);
	if (!host) {
		printk(KERN_ERR "%s:%d fail (no memory for mg_host)\n",
				__func__, __LINE__);
		err = -ENOMEM;
		goto probe_err;
	}
	host->major = MG_DISK_MAJ;

	/* link each other */
	prv_data->host = host;
	host->dev = &plat_dev->dev;

	/* io remap */
	rsc = platform_get_resource(plat_dev, IORESOURCE_MEM, 0);
	if (!rsc) {
		printk(KERN_ERR "%s:%d platform_get_resource fail\n",
				__func__, __LINE__);
		err = -EINVAL;
		goto probe_err_2;
	}
	host->dev_base = ioremap(rsc->start , rsc->end + 1);
	if (!host->dev_base) {
		printk(KERN_ERR "%s:%d ioremap fail\n",
				__func__, __LINE__);
		err = -EIO;
		goto probe_err_2;
	}
	MG_DBG("dev_base = 0x%x\n", (u32)host->dev_base);

	/* get reset pin */
	rsc = platform_get_resource_byname(plat_dev, IORESOURCE_IO,
			MG_RST_PIN);
	if (!rsc) {
		printk(KERN_ERR "%s:%d get reset pin fail\n",
				__func__, __LINE__);
		err = -EIO;
		goto probe_err_3;
	}
	host->rst = rsc->start;

	/* init rst pin */
	err = gpio_request(host->rst, MG_RST_PIN);
	if (err)
		goto probe_err_3;
	gpio_direction_output(host->rst, 1);

	/* reset out pin */
	if (!(prv_data->dev_attr & MG_DEV_MASK))
		goto probe_err_3a;

	if (prv_data->dev_attr != MG_BOOT_DEV) {
		rsc = platform_get_resource_byname(plat_dev, IORESOURCE_IO,
				MG_RSTOUT_PIN);
		if (!rsc) {
			printk(KERN_ERR "%s:%d get reset-out pin fail\n",
					__func__, __LINE__);
			err = -EIO;
			goto probe_err_3a;
		}
		host->rstout = rsc->start;
		err = gpio_request(host->rstout, MG_RSTOUT_PIN);
		if (err)
			goto probe_err_3a;
		gpio_direction_input(host->rstout);
	}

	/* disk reset */
	if (prv_data->dev_attr == MG_STORAGE_DEV) {
		/* If POR seq. not yet finised, wait */
		err = mg_wait_rstout(host->rstout, MG_TMAX_RSTOUT);
		if (err)
			goto probe_err_3b;
		err = mg_disk_init(host);
		if (err) {
			printk(KERN_ERR "%s:%d fail (err code : %d)\n",
					__func__, __LINE__, err);
			err = -EIO;
			goto probe_err_3b;
		}
	}

	/* get irq resource */
	if (!prv_data->use_polling) {
		host->irq = platform_get_irq(plat_dev, 0);
		if (host->irq == -ENXIO) {
			err = host->irq;
			goto probe_err_3b;
		}
		err = request_irq(host->irq, mg_irq,
				IRQF_DISABLED | IRQF_TRIGGER_RISING,
				MG_DEV_NAME, host);
		if (err) {
			printk(KERN_ERR "%s:%d fail (request_irq err=%d)\n",
					__func__, __LINE__, err);
			goto probe_err_3b;
		}

	}

	/* get disk id */
	err = mg_get_disk_id(host);
	if (err) {
		printk(KERN_ERR "%s:%d fail (err code : %d)\n",
				__func__, __LINE__, err);
		err = -EIO;
		goto probe_err_4;
	}

	err = register_blkdev(host->major, MG_DISK_NAME);
	if (err < 0) {
		printk(KERN_ERR "%s:%d register_blkdev fail (err code : %d)\n",
				__func__, __LINE__, err);
		goto probe_err_4;
	}
	if (!host->major)
		host->major = err;

	spin_lock_init(&host->lock);

	if (prv_data->use_polling)
		host->breq = blk_init_queue(mg_request_poll, &host->lock);
	else
		host->breq = blk_init_queue(mg_request, &host->lock);

	if (!host->breq) {
		err = -ENOMEM;
		printk(KERN_ERR "%s:%d (blk_init_queue) fail\n",
				__func__, __LINE__);
		goto probe_err_5;
	}
	host->breq->queuedata = host;

	/* mflash is random device, thanx for the noop */
	elevator_exit(host->breq->elevator);
	err = elevator_init(host->breq, "noop");
	if (err) {
		printk(KERN_ERR "%s:%d (elevator_init) fail\n",
				__func__, __LINE__);
		goto probe_err_6;
	}
	blk_queue_max_sectors(host->breq, MG_MAX_SECTS);
	blk_queue_logical_block_size(host->breq, MG_SECTOR_SIZE);

	init_timer(&host->timer);
	host->timer.function = mg_times_out;
	host->timer.data = (unsigned long)host;

	host->gd = alloc_disk(MG_DISK_MAX_PART);
	if (!host->gd) {
		printk(KERN_ERR "%s:%d (alloc_disk) fail\n",
				__func__, __LINE__);
		err = -ENOMEM;
		goto probe_err_7;
	}
	host->gd->major = host->major;
	host->gd->first_minor = 0;
	host->gd->fops = &mg_disk_ops;
	host->gd->queue = host->breq;
	host->gd->private_data = host;
	sprintf(host->gd->disk_name, MG_DISK_NAME"a");

	set_capacity(host->gd, host->n_sectors);

	add_disk(host->gd);

	return err;

probe_err_7:
	del_timer_sync(&host->timer);
probe_err_6:
	blk_cleanup_queue(host->breq);
probe_err_5:
	unregister_blkdev(MG_DISK_MAJ, MG_DISK_NAME);
probe_err_4:
	if (!prv_data->use_polling)
		free_irq(host->irq, host);
probe_err_3b:
	gpio_free(host->rstout);
probe_err_3a:
	gpio_free(host->rst);
probe_err_3:
	iounmap(host->dev_base);
probe_err_2:
	kfree(host);
probe_err:
	return err;
}

static int mg_remove(struct platform_device *plat_dev)
{
	struct mg_drv_data *prv_data = plat_dev->dev.platform_data;
	struct mg_host *host = prv_data->host;
	int err = 0;

	/* delete timer */
	del_timer_sync(&host->timer);

	/* remove disk */
	if (host->gd) {
		del_gendisk(host->gd);
		put_disk(host->gd);
	}
	/* remove queue */
	if (host->breq)
		blk_cleanup_queue(host->breq);

	/* unregister blk device */
	unregister_blkdev(host->major, MG_DISK_NAME);

	/* free irq */
	if (!prv_data->use_polling)
		free_irq(host->irq, host);

	/* free reset-out pin */
	if (prv_data->dev_attr != MG_BOOT_DEV)
		gpio_free(host->rstout);

	/* free rst pin */
	if (host->rst)
		gpio_free(host->rst);

	/* unmap io */
	if (host->dev_base)
		iounmap(host->dev_base);

	/* free mg_host */
	kfree(host);

	return err;
}

static struct platform_driver mg_disk_driver = {
	.probe = mg_probe,
	.remove = mg_remove,
	.suspend = mg_suspend,
	.resume = mg_resume,
	.driver = {
		.name = MG_DEV_NAME,
		.owner = THIS_MODULE,
	}
};

/****************************************************************************
 *
 * Module stuff
 *
 ****************************************************************************/

static int __init mg_init(void)
{
	printk(KERN_INFO "mGine mflash driver, (c) 2008 mGine Co.\n");
	return platform_driver_register(&mg_disk_driver);
}

static void __exit mg_exit(void)
{
	printk(KERN_INFO "mflash driver : bye bye\n");
	platform_driver_unregister(&mg_disk_driver);
}

module_init(mg_init);
module_exit(mg_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("unsik Kim <donari75@gmail.com>");
MODULE_DESCRIPTION("mGine m[g]flash device driver");