Free Electrons

Embedded Linux Experts

   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
/*
 * Copyright (C) 1996-1999  Gadi Oxman <gadio@netvision.net.il>
 * Copyright (C) 2004-2005  Bartlomiej Zolnierkiewicz
 */

/*
 * Emulation of a SCSI host adapter for IDE ATAPI devices.
 *
 * With this driver, one can use the Linux SCSI drivers instead of the
 * native IDE ATAPI drivers.
 *
 * Ver 0.1   Dec  3 96   Initial version.
 * Ver 0.2   Jan 26 97   Fixed bug in cleanup_module() and added emulation
 *                        of MODE_SENSE_6/MODE_SELECT_6 for cdroms. Thanks
 *                        to Janos Farkas for pointing this out.
 *                       Avoid using bitfields in structures for m68k.
 *                       Added Scatter/Gather and DMA support.
 * Ver 0.4   Dec  7 97   Add support for ATAPI PD/CD drives.
 *                       Use variable timeout for each command.
 * Ver 0.5   Jan  2 98   Fix previous PD/CD support.
 *                       Allow disabling of SCSI-6 to SCSI-10 transformation.
 * Ver 0.6   Jan 27 98   Allow disabling of SCSI command translation layer
 *                        for access through /dev/sg.
 *                       Fix MODE_SENSE_6/MODE_SELECT_6/INQUIRY translation.
 * Ver 0.7   Dec 04 98   Ignore commands where lun != 0 to avoid multiple
 *                        detection of devices with CONFIG_SCSI_MULTI_LUN
 * Ver 0.8   Feb 05 99   Optical media need translation too. Reverse 0.7.
 * Ver 0.9   Jul 04 99   Fix a bug in SG_SET_TRANSFORM.
 * Ver 0.91  Jun 10 02   Fix "off by one" error in transforms
 * Ver 0.92  Dec 31 02   Implement new SCSI mid level API
 */

#define IDESCSI_VERSION "0.92"

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/ioport.h>
#include <linux/blkdev.h>
#include <linux/errno.h>
#include <linux/hdreg.h>
#include <linux/slab.h>
#include <linux/ide.h>
#include <linux/scatterlist.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/bitops.h>

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

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>
#include <scsi/sg.h>

#define IDESCSI_DEBUG_LOG		0

typedef struct idescsi_pc_s {
	u8 c[12];				/* Actual packet bytes */
	int request_transfer;			/* Bytes to transfer */
	int actually_transferred;		/* Bytes actually transferred */
	int buffer_size;			/* Size of our data buffer */
	struct request *rq;			/* The corresponding request */
	u8 *buffer;				/* Data buffer */
	u8 *current_position;			/* Pointer into the above buffer */
	struct scatterlist *sg;			/* Scatter gather table */
	unsigned int sg_cnt;			/* Number of entries in sg */
	int b_count;				/* Bytes transferred from current entry */
	struct scsi_cmnd *scsi_cmd;		/* SCSI command */
	void (*done)(struct scsi_cmnd *);	/* Scsi completion routine */
	unsigned long flags;			/* Status/Action flags */
	unsigned long timeout;			/* Command timeout */
} idescsi_pc_t;

/*
 *	Packet command status bits.
 */
#define PC_DMA_IN_PROGRESS		0	/* 1 while DMA in progress */
#define PC_WRITING			1	/* Data direction */
#define PC_TIMEDOUT			3	/* command timed out */
#define PC_DMA_OK			4	/* Use DMA */

/*
 *	SCSI command transformation layer
 */
#define IDESCSI_SG_TRANSFORM		1	/* /dev/sg transformation */

/*
 *	Log flags
 */
#define IDESCSI_LOG_CMD			0	/* Log SCSI commands */

typedef struct ide_scsi_obj {
	ide_drive_t		*drive;
	ide_driver_t		*driver;
	struct gendisk		*disk;
	struct Scsi_Host	*host;

	idescsi_pc_t *pc;			/* Current packet command */
	unsigned long flags;			/* Status/Action flags */
	unsigned long transform;		/* SCSI cmd translation layer */
	unsigned long log;			/* log flags */
} idescsi_scsi_t;

static DEFINE_MUTEX(idescsi_ref_mutex);
static int idescsi_nocd;			/* Set by module param to skip cd */

#define ide_scsi_g(disk) \
	container_of((disk)->private_data, struct ide_scsi_obj, driver)

static struct ide_scsi_obj *ide_scsi_get(struct gendisk *disk)
{
	struct ide_scsi_obj *scsi = NULL;

	mutex_lock(&idescsi_ref_mutex);
	scsi = ide_scsi_g(disk);
	if (scsi)
		scsi_host_get(scsi->host);
	mutex_unlock(&idescsi_ref_mutex);
	return scsi;
}

static void ide_scsi_put(struct ide_scsi_obj *scsi)
{
	mutex_lock(&idescsi_ref_mutex);
	scsi_host_put(scsi->host);
	mutex_unlock(&idescsi_ref_mutex);
}

static inline idescsi_scsi_t *scsihost_to_idescsi(struct Scsi_Host *host)
{
	return (idescsi_scsi_t*) (&host[1]);
}

static inline idescsi_scsi_t *drive_to_idescsi(ide_drive_t *ide_drive)
{
	return scsihost_to_idescsi(ide_drive->driver_data);
}

/*
 *	Per ATAPI device status bits.
 */
#define IDESCSI_DRQ_INTERRUPT		0	/* DRQ interrupt device */

/*
 *	ide-scsi requests.
 */
#define IDESCSI_PC_RQ			90

static void idescsi_discard_data (ide_drive_t *drive, unsigned int bcount)
{
	while (bcount--)
		(void) HWIF(drive)->INB(IDE_DATA_REG);
}

static void idescsi_output_zeros (ide_drive_t *drive, unsigned int bcount)
{
	while (bcount--)
		HWIF(drive)->OUTB(0, IDE_DATA_REG);
}

/*
 *	PIO data transfer routines using the scatter gather table.
 */
static void idescsi_input_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigned int bcount)
{
	int count;
	char *buf;

	while (bcount) {
		count = min(pc->sg->length - pc->b_count, bcount);
		if (PageHighMem(sg_page(pc->sg))) {
			unsigned long flags;

			local_irq_save(flags);
			buf = kmap_atomic(sg_page(pc->sg), KM_IRQ0) +
					pc->sg->offset;
			drive->hwif->atapi_input_bytes(drive,
						buf + pc->b_count, count);
			kunmap_atomic(buf - pc->sg->offset, KM_IRQ0);
			local_irq_restore(flags);
		} else {
			buf = sg_virt(pc->sg);
			drive->hwif->atapi_input_bytes(drive,
						buf + pc->b_count, count);
		}
		bcount -= count; pc->b_count += count;
		if (pc->b_count == pc->sg->length) {
			if (!--pc->sg_cnt)
				break;
			pc->sg = sg_next(pc->sg);
			pc->b_count = 0;
		}
	}

	if (bcount) {
		printk (KERN_ERR "ide-scsi: scatter gather table too small, discarding data\n");
		idescsi_discard_data (drive, bcount);
	}
}

static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigned int bcount)
{
	int count;
	char *buf;

	while (bcount) {
		count = min(pc->sg->length - pc->b_count, bcount);
		if (PageHighMem(sg_page(pc->sg))) {
			unsigned long flags;

			local_irq_save(flags);
			buf = kmap_atomic(sg_page(pc->sg), KM_IRQ0) +
						pc->sg->offset;
			drive->hwif->atapi_output_bytes(drive,
						buf + pc->b_count, count);
			kunmap_atomic(buf - pc->sg->offset, KM_IRQ0);
			local_irq_restore(flags);
		} else {
			buf = sg_virt(pc->sg);
			drive->hwif->atapi_output_bytes(drive,
						buf + pc->b_count, count);
		}
		bcount -= count; pc->b_count += count;
		if (pc->b_count == pc->sg->length) {
			if (!--pc->sg_cnt)
				break;
			pc->sg = sg_next(pc->sg);
			pc->b_count = 0;
		}
	}

	if (bcount) {
		printk (KERN_ERR "ide-scsi: scatter gather table too small, padding with zeros\n");
		idescsi_output_zeros (drive, bcount);
	}
}

static void ide_scsi_hex_dump(u8 *data, int len)
{
	print_hex_dump(KERN_CONT, "", DUMP_PREFIX_NONE, 16, 1, data, len, 0);
}

static int idescsi_check_condition(ide_drive_t *drive, struct request *failed_command)
{
	idescsi_scsi_t *scsi = drive_to_idescsi(drive);
	idescsi_pc_t   *pc;
	struct request *rq;
	u8             *buf;

	/* stuff a sense request in front of our current request */
	pc = kzalloc(sizeof(idescsi_pc_t), GFP_ATOMIC);
	rq = kmalloc(sizeof(struct request), GFP_ATOMIC);
	buf = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_ATOMIC);
	if (!pc || !rq || !buf) {
		kfree(buf);
		kfree(rq);
		kfree(pc);
		return -ENOMEM;
	}
	ide_init_drive_cmd(rq);
	rq->special = (char *) pc;
	pc->rq = rq;
	pc->buffer = buf;
	pc->c[0] = REQUEST_SENSE;
	pc->c[4] = pc->request_transfer = pc->buffer_size = SCSI_SENSE_BUFFERSIZE;
	rq->cmd_type = REQ_TYPE_SENSE;
	pc->timeout = jiffies + WAIT_READY;
	/* NOTE! Save the failed packet command in "rq->buffer" */
	rq->buffer = (void *) failed_command->special;
	pc->scsi_cmd = ((idescsi_pc_t *) failed_command->special)->scsi_cmd;
	if (test_bit(IDESCSI_LOG_CMD, &scsi->log)) {
		printk ("ide-scsi: %s: queue cmd = ", drive->name);
		ide_scsi_hex_dump(pc->c, 6);
	}
	rq->rq_disk = scsi->disk;
	return ide_do_drive_cmd(drive, rq, ide_preempt);
}

static int idescsi_end_request(ide_drive_t *, int, int);

static ide_startstop_t
idescsi_atapi_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
{
	if (ide_read_status(drive) & (BUSY_STAT | DRQ_STAT))
		/* force an abort */
		HWIF(drive)->OUTB(WIN_IDLEIMMEDIATE,IDE_COMMAND_REG);

	rq->errors++;

	idescsi_end_request(drive, 0, 0);

	return ide_stopped;
}

static ide_startstop_t
idescsi_atapi_abort(ide_drive_t *drive, struct request *rq)
{
#if IDESCSI_DEBUG_LOG
	printk(KERN_WARNING "idescsi_atapi_abort called for %lu\n",
			((idescsi_pc_t *) rq->special)->scsi_cmd->serial_number);
#endif
	rq->errors |= ERROR_MAX;

	idescsi_end_request(drive, 0, 0);

	return ide_stopped;
}

static int idescsi_end_request (ide_drive_t *drive, int uptodate, int nrsecs)
{
	idescsi_scsi_t *scsi = drive_to_idescsi(drive);
	struct request *rq = HWGROUP(drive)->rq;
	idescsi_pc_t *pc = (idescsi_pc_t *) rq->special;
	int log = test_bit(IDESCSI_LOG_CMD, &scsi->log);
	struct Scsi_Host *host;
	int errors = rq->errors;
	unsigned long flags;

	if (!blk_special_request(rq) && !blk_sense_request(rq)) {
		ide_end_request(drive, uptodate, nrsecs);
		return 0;
	}
	ide_end_drive_cmd (drive, 0, 0);
	if (blk_sense_request(rq)) {
		idescsi_pc_t *opc = (idescsi_pc_t *) rq->buffer;
		if (log) {
			printk ("ide-scsi: %s: wrap up check %lu, rst = ", drive->name, opc->scsi_cmd->serial_number);
			ide_scsi_hex_dump(pc->buffer, 16);
		}
		memcpy((void *) opc->scsi_cmd->sense_buffer, pc->buffer, SCSI_SENSE_BUFFERSIZE);
		kfree(pc->buffer);
		kfree(pc);
		kfree(rq);
		pc = opc;
		rq = pc->rq;
		pc->scsi_cmd->result = (CHECK_CONDITION << 1) |
					((test_bit(PC_TIMEDOUT, &pc->flags)?DID_TIME_OUT:DID_OK) << 16);
	} else if (test_bit(PC_TIMEDOUT, &pc->flags)) {
		if (log)
			printk (KERN_WARNING "ide-scsi: %s: timed out for %lu\n",
					drive->name, pc->scsi_cmd->serial_number);
		pc->scsi_cmd->result = DID_TIME_OUT << 16;
	} else if (errors >= ERROR_MAX) {
		pc->scsi_cmd->result = DID_ERROR << 16;
		if (log)
			printk ("ide-scsi: %s: I/O error for %lu\n", drive->name, pc->scsi_cmd->serial_number);
	} else if (errors) {
		if (log)
			printk ("ide-scsi: %s: check condition for %lu\n", drive->name, pc->scsi_cmd->serial_number);
		if (!idescsi_check_condition(drive, rq))
			/* we started a request sense, so we'll be back, exit for now */
			return 0;
		pc->scsi_cmd->result = (CHECK_CONDITION << 1) | (DID_OK << 16);
	} else {
		pc->scsi_cmd->result = DID_OK << 16;
	}
	host = pc->scsi_cmd->device->host;
	spin_lock_irqsave(host->host_lock, flags);
	pc->done(pc->scsi_cmd);
	spin_unlock_irqrestore(host->host_lock, flags);
	kfree(pc);
	kfree(rq);
	scsi->pc = NULL;
	return 0;
}

static inline unsigned long get_timeout(idescsi_pc_t *pc)
{
	return max_t(unsigned long, WAIT_CMD, pc->timeout - jiffies);
}

static int idescsi_expiry(ide_drive_t *drive)
{
	idescsi_scsi_t *scsi = drive_to_idescsi(drive);
	idescsi_pc_t   *pc   = scsi->pc;

#if IDESCSI_DEBUG_LOG
	printk(KERN_WARNING "idescsi_expiry called for %lu at %lu\n", pc->scsi_cmd->serial_number, jiffies);
#endif
	set_bit(PC_TIMEDOUT, &pc->flags);

	return 0;					/* we do not want the ide subsystem to retry */
}

/*
 *	Our interrupt handler.
 */
static ide_startstop_t idescsi_pc_intr (ide_drive_t *drive)
{
	idescsi_scsi_t *scsi = drive_to_idescsi(drive);
	ide_hwif_t *hwif = drive->hwif;
	idescsi_pc_t *pc = scsi->pc;
	struct request *rq = pc->rq;
	unsigned int temp;
	u16 bcount;
	u8 stat, ireason;

#if IDESCSI_DEBUG_LOG
	printk (KERN_INFO "ide-scsi: Reached idescsi_pc_intr interrupt handler\n");
#endif /* IDESCSI_DEBUG_LOG */

	if (test_bit(PC_TIMEDOUT, &pc->flags)){
#if IDESCSI_DEBUG_LOG
		printk(KERN_WARNING "idescsi_pc_intr: got timed out packet  %lu at %lu\n",
				pc->scsi_cmd->serial_number, jiffies);
#endif
		/* end this request now - scsi should retry it*/
		idescsi_end_request (drive, 1, 0);
		return ide_stopped;
	}
	if (test_and_clear_bit (PC_DMA_IN_PROGRESS, &pc->flags)) {
#if IDESCSI_DEBUG_LOG
		printk ("ide-scsi: %s: DMA complete\n", drive->name);
#endif /* IDESCSI_DEBUG_LOG */
		pc->actually_transferred=pc->request_transfer;
		(void) HWIF(drive)->ide_dma_end(drive);
	}

	/* Clear the interrupt */
	stat = ide_read_status(drive);

	if ((stat & DRQ_STAT) == 0) {
		/* No more interrupts */
		if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
			printk (KERN_INFO "Packet command completed, %d bytes transferred\n", pc->actually_transferred);
		local_irq_enable_in_hardirq();
		if (stat & ERR_STAT)
			rq->errors++;
		idescsi_end_request (drive, 1, 0);
		return ide_stopped;
	}
	bcount = (hwif->INB(IDE_BCOUNTH_REG) << 8) |
		  hwif->INB(IDE_BCOUNTL_REG);
	ireason = hwif->INB(IDE_IREASON_REG);

	if (ireason & CD) {
		printk(KERN_ERR "ide-scsi: CoD != 0 in idescsi_pc_intr\n");
		return ide_do_reset (drive);
	}
	if (ireason & IO) {
		temp = pc->actually_transferred + bcount;
		if (temp > pc->request_transfer) {
			if (temp > pc->buffer_size) {
				printk(KERN_ERR "ide-scsi: The scsi wants to "
					"send us more data than expected "
					"- discarding data\n");
				temp = pc->buffer_size - pc->actually_transferred;
				if (temp) {
					clear_bit(PC_WRITING, &pc->flags);
					if (pc->sg)
						idescsi_input_buffers(drive, pc, temp);
					else
						drive->hwif->atapi_input_bytes(drive, pc->current_position, temp);
					printk(KERN_ERR "ide-scsi: transferred"
							" %d of %d bytes\n",
							temp, bcount);
				}
				pc->actually_transferred += temp;
				pc->current_position += temp;
				idescsi_discard_data(drive, bcount - temp);
				ide_set_handler(drive, &idescsi_pc_intr, get_timeout(pc), idescsi_expiry);
				return ide_started;
			}
#if IDESCSI_DEBUG_LOG
			printk (KERN_NOTICE "ide-scsi: The scsi wants to send us more data than expected - allowing transfer\n");
#endif /* IDESCSI_DEBUG_LOG */
		}
	}
	if (ireason & IO) {
		clear_bit(PC_WRITING, &pc->flags);
		if (pc->sg)
			idescsi_input_buffers(drive, pc, bcount);
		else
			hwif->atapi_input_bytes(drive, pc->current_position,
						bcount);
	} else {
		set_bit(PC_WRITING, &pc->flags);
		if (pc->sg)
			idescsi_output_buffers(drive, pc, bcount);
		else
			hwif->atapi_output_bytes(drive, pc->current_position,
						 bcount);
	}
	/* Update the current position */
	pc->actually_transferred += bcount;
	pc->current_position += bcount;

	/* And set the interrupt handler again */
	ide_set_handler(drive, &idescsi_pc_intr, get_timeout(pc), idescsi_expiry);
	return ide_started;
}

static ide_startstop_t idescsi_transfer_pc(ide_drive_t *drive)
{
	ide_hwif_t *hwif = drive->hwif;
	idescsi_scsi_t *scsi = drive_to_idescsi(drive);
	idescsi_pc_t *pc = scsi->pc;
	ide_startstop_t startstop;
	u8 ireason;

	if (ide_wait_stat(&startstop,drive,DRQ_STAT,BUSY_STAT,WAIT_READY)) {
		printk(KERN_ERR "ide-scsi: Strange, packet command "
			"initiated yet DRQ isn't asserted\n");
		return startstop;
	}
	ireason = hwif->INB(IDE_IREASON_REG);
	if ((ireason & CD) == 0 || (ireason & IO)) {
		printk(KERN_ERR "ide-scsi: (IO,CoD) != (0,1) while "
				"issuing a packet command\n");
		return ide_do_reset (drive);
	}
	BUG_ON(HWGROUP(drive)->handler != NULL);
	/* Set the interrupt routine */
	ide_set_handler(drive, &idescsi_pc_intr, get_timeout(pc), idescsi_expiry);
	/* Send the actual packet */
	drive->hwif->atapi_output_bytes(drive, scsi->pc->c, 12);
	if (test_bit (PC_DMA_OK, &pc->flags)) {
		set_bit (PC_DMA_IN_PROGRESS, &pc->flags);
		hwif->dma_start(drive);
	}
	return ide_started;
}

static inline int idescsi_set_direction(idescsi_pc_t *pc)
{
	switch (pc->c[0]) {
		case READ_6: case READ_10: case READ_12:
			clear_bit(PC_WRITING, &pc->flags);
			return 0;
		case WRITE_6: case WRITE_10: case WRITE_12:
			set_bit(PC_WRITING, &pc->flags);
			return 0;
		default:
			return 1;
	}
}

static int idescsi_map_sg(ide_drive_t *drive, idescsi_pc_t *pc)
{
	ide_hwif_t *hwif = drive->hwif;
	struct scatterlist *sg, *scsi_sg;
	int segments;

	if (!pc->request_transfer || pc->request_transfer % 1024)
		return 1;

	if (idescsi_set_direction(pc))
		return 1;

	sg = hwif->sg_table;
	scsi_sg = scsi_sglist(pc->scsi_cmd);
	segments = scsi_sg_count(pc->scsi_cmd);

	if (segments > hwif->sg_max_nents)
		return 1;

	hwif->sg_nents = segments;
	memcpy(sg, scsi_sg, sizeof(*sg) * segments);

	return 0;
}

/*
 *	Issue a packet command
 */
static ide_startstop_t idescsi_issue_pc (ide_drive_t *drive, idescsi_pc_t *pc)
{
	idescsi_scsi_t *scsi = drive_to_idescsi(drive);
	ide_hwif_t *hwif = drive->hwif;
	u16 bcount;
	u8 dma = 0;

	scsi->pc=pc;							/* Set the current packet command */
	pc->actually_transferred=0;					/* We haven't transferred any data yet */
	pc->current_position=pc->buffer;
	/* Request to transfer the entire buffer at once */
	bcount = min(pc->request_transfer, 63 * 1024);

	if (drive->using_dma && !idescsi_map_sg(drive, pc)) {
		hwif->sg_mapped = 1;
		dma = !hwif->dma_setup(drive);
		hwif->sg_mapped = 0;
	}

	ide_pktcmd_tf_load(drive, IDE_TFLAG_NO_SELECT_MASK, bcount, dma);

	if (dma)
		set_bit(PC_DMA_OK, &pc->flags);

	if (test_bit(IDESCSI_DRQ_INTERRUPT, &scsi->flags)) {
		ide_execute_command(drive, WIN_PACKETCMD, &idescsi_transfer_pc,
				    get_timeout(pc), idescsi_expiry);
		return ide_started;
	} else {
		/* Issue the packet command */
		HWIF(drive)->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
		return idescsi_transfer_pc(drive);
	}
}

/*
 *	idescsi_do_request is our request handling function.
 */
static ide_startstop_t idescsi_do_request (ide_drive_t *drive, struct request *rq, sector_t block)
{
#if IDESCSI_DEBUG_LOG
	printk (KERN_INFO "dev: %s, cmd: %x, errors: %d\n", rq->rq_disk->disk_name,rq->cmd[0],rq->errors);
	printk (KERN_INFO "sector: %ld, nr_sectors: %ld, current_nr_sectors: %d\n",rq->sector,rq->nr_sectors,rq->current_nr_sectors);
#endif /* IDESCSI_DEBUG_LOG */

	if (blk_sense_request(rq) || blk_special_request(rq)) {
		return idescsi_issue_pc (drive, (idescsi_pc_t *) rq->special);
	}
	blk_dump_rq_flags(rq, "ide-scsi: unsup command");
	idescsi_end_request (drive, 0, 0);
	return ide_stopped;
}

#ifdef CONFIG_IDE_PROC_FS
static void idescsi_add_settings(ide_drive_t *drive)
{
	idescsi_scsi_t *scsi = drive_to_idescsi(drive);

/*
 *			drive	setting name	read/write	data type	min	max	mul_factor	div_factor	data pointer		set function
 */
	ide_add_setting(drive,	"bios_cyl",	SETTING_RW,	TYPE_INT,	0,	1023,	1,		1,		&drive->bios_cyl,	NULL);
	ide_add_setting(drive,	"bios_head",	SETTING_RW,	TYPE_BYTE,	0,	255,	1,		1,		&drive->bios_head,	NULL);
	ide_add_setting(drive,	"bios_sect",	SETTING_RW,	TYPE_BYTE,	0,	63,	1,		1,		&drive->bios_sect,	NULL);
	ide_add_setting(drive,	"transform",	SETTING_RW,	TYPE_INT,	0,	3,	1,		1,		&scsi->transform,	NULL);
	ide_add_setting(drive,	"log",		SETTING_RW,	TYPE_INT,	0,	1,	1,		1,		&scsi->log,		NULL);
}
#else
static inline void idescsi_add_settings(ide_drive_t *drive) { ; }
#endif

/*
 *	Driver initialization.
 */
static void idescsi_setup (ide_drive_t *drive, idescsi_scsi_t *scsi)
{
	if (drive->id && (drive->id->config & 0x0060) == 0x20)
		set_bit (IDESCSI_DRQ_INTERRUPT, &scsi->flags);
	clear_bit(IDESCSI_SG_TRANSFORM, &scsi->transform);
#if IDESCSI_DEBUG_LOG
	set_bit(IDESCSI_LOG_CMD, &scsi->log);
#endif /* IDESCSI_DEBUG_LOG */
	idescsi_add_settings(drive);
}

static void ide_scsi_remove(ide_drive_t *drive)
{
	struct Scsi_Host *scsihost = drive->driver_data;
	struct ide_scsi_obj *scsi = scsihost_to_idescsi(scsihost);
	struct gendisk *g = scsi->disk;

	scsi_remove_host(scsihost);
	ide_proc_unregister_driver(drive, scsi->driver);

	ide_unregister_region(g);

	drive->driver_data = NULL;
	g->private_data = NULL;
	put_disk(g);

	ide_scsi_put(scsi);
}

static int ide_scsi_probe(ide_drive_t *);

#ifdef CONFIG_IDE_PROC_FS
static ide_proc_entry_t idescsi_proc[] = {
	{ "capacity", S_IFREG|S_IRUGO, proc_ide_read_capacity, NULL },
	{ NULL, 0, NULL, NULL }
};
#endif

static ide_driver_t idescsi_driver = {
	.gen_driver = {
		.owner		= THIS_MODULE,
		.name		= "ide-scsi",
		.bus		= &ide_bus_type,
	},
	.probe			= ide_scsi_probe,
	.remove			= ide_scsi_remove,
	.version		= IDESCSI_VERSION,
	.media			= ide_scsi,
	.supports_dsc_overlap	= 0,
	.do_request		= idescsi_do_request,
	.end_request		= idescsi_end_request,
	.error                  = idescsi_atapi_error,
	.abort                  = idescsi_atapi_abort,
#ifdef CONFIG_IDE_PROC_FS
	.proc			= idescsi_proc,
#endif
};

static int idescsi_ide_open(struct inode *inode, struct file *filp)
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	struct ide_scsi_obj *scsi;

	if (!(scsi = ide_scsi_get(disk)))
		return -ENXIO;

	return 0;
}

static int idescsi_ide_release(struct inode *inode, struct file *filp)
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	struct ide_scsi_obj *scsi = ide_scsi_g(disk);

	ide_scsi_put(scsi);

	return 0;
}

static int idescsi_ide_ioctl(struct inode *inode, struct file *file,
			unsigned int cmd, unsigned long arg)
{
	struct block_device *bdev = inode->i_bdev;
	struct ide_scsi_obj *scsi = ide_scsi_g(bdev->bd_disk);
	return generic_ide_ioctl(scsi->drive, file, bdev, cmd, arg);
}

static struct block_device_operations idescsi_ops = {
	.owner		= THIS_MODULE,
	.open		= idescsi_ide_open,
	.release	= idescsi_ide_release,
	.ioctl		= idescsi_ide_ioctl,
};

static int idescsi_slave_configure(struct scsi_device * sdp)
{
	/* Configure detected device */
	sdp->use_10_for_rw = 1;
	sdp->use_10_for_ms = 1;
	scsi_adjust_queue_depth(sdp, MSG_SIMPLE_TAG, sdp->host->cmd_per_lun);
	return 0;
}

static const char *idescsi_info (struct Scsi_Host *host)
{
	return "SCSI host adapter emulation for IDE ATAPI devices";
}

static int idescsi_ioctl (struct scsi_device *dev, int cmd, void __user *arg)
{
	idescsi_scsi_t *scsi = scsihost_to_idescsi(dev->host);

	if (cmd == SG_SET_TRANSFORM) {
		if (arg)
			set_bit(IDESCSI_SG_TRANSFORM, &scsi->transform);
		else
			clear_bit(IDESCSI_SG_TRANSFORM, &scsi->transform);
		return 0;
	} else if (cmd == SG_GET_TRANSFORM)
		return put_user(test_bit(IDESCSI_SG_TRANSFORM, &scsi->transform), (int __user *) arg);
	return -EINVAL;
}

static int idescsi_queue (struct scsi_cmnd *cmd,
		void (*done)(struct scsi_cmnd *))
{
	struct Scsi_Host *host = cmd->device->host;
	idescsi_scsi_t *scsi = scsihost_to_idescsi(host);
	ide_drive_t *drive = scsi->drive;
	struct request *rq = NULL;
	idescsi_pc_t *pc = NULL;

	if (!drive) {
		scmd_printk (KERN_ERR, cmd, "drive not present\n");
		goto abort;
	}
	scsi = drive_to_idescsi(drive);
	pc = kmalloc (sizeof (idescsi_pc_t), GFP_ATOMIC);
	rq = kmalloc (sizeof (struct request), GFP_ATOMIC);
	if (rq == NULL || pc == NULL) {
		printk (KERN_ERR "ide-scsi: %s: out of memory\n", drive->name);
		goto abort;
	}

	memset (pc->c, 0, 12);
	pc->flags = 0;
	pc->rq = rq;
	memcpy (pc->c, cmd->cmnd, cmd->cmd_len);
	pc->buffer = NULL;
	pc->sg = scsi_sglist(cmd);
	pc->sg_cnt = scsi_sg_count(cmd);
	pc->b_count = 0;
	pc->request_transfer = pc->buffer_size = scsi_bufflen(cmd);
	pc->scsi_cmd = cmd;
	pc->done = done;
	pc->timeout = jiffies + cmd->timeout_per_command;

	if (test_bit(IDESCSI_LOG_CMD, &scsi->log)) {
		printk ("ide-scsi: %s: que %lu, cmd = ", drive->name, cmd->serial_number);
		ide_scsi_hex_dump(cmd->cmnd, cmd->cmd_len);
		if (memcmp(pc->c, cmd->cmnd, cmd->cmd_len)) {
			printk ("ide-scsi: %s: que %lu, tsl = ", drive->name, cmd->serial_number);
			ide_scsi_hex_dump(pc->c, 12);
		}
	}

	ide_init_drive_cmd (rq);
	rq->special = (char *) pc;
	rq->cmd_type = REQ_TYPE_SPECIAL;
	spin_unlock_irq(host->host_lock);
	rq->rq_disk = scsi->disk;
	(void) ide_do_drive_cmd (drive, rq, ide_end);
	spin_lock_irq(host->host_lock);
	return 0;
abort:
	kfree (pc);
	kfree (rq);
	cmd->result = DID_ERROR << 16;
	done(cmd);
	return 0;
}

static int idescsi_eh_abort (struct scsi_cmnd *cmd)
{
	idescsi_scsi_t *scsi  = scsihost_to_idescsi(cmd->device->host);
	ide_drive_t    *drive = scsi->drive;
	int		busy;
	int             ret   = FAILED;

	/* In idescsi_eh_abort we try to gently pry our command from the ide subsystem */

	if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
		printk (KERN_WARNING "ide-scsi: abort called for %lu\n", cmd->serial_number);

	if (!drive) {
		printk (KERN_WARNING "ide-scsi: Drive not set in idescsi_eh_abort\n");
		WARN_ON(1);
		goto no_drive;
	}

	/* First give it some more time, how much is "right" is hard to say :-( */

	busy = ide_wait_not_busy(HWIF(drive), 100);	/* FIXME - uses mdelay which causes latency? */
	if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
		printk (KERN_WARNING "ide-scsi: drive did%s become ready\n", busy?" not":"");

	spin_lock_irq(&ide_lock);

	/* If there is no pc running we're done (our interrupt took care of it) */
	if (!scsi->pc) {
		ret = SUCCESS;
		goto ide_unlock;
	}

	/* It's somewhere in flight. Does ide subsystem agree? */
	if (scsi->pc->scsi_cmd->serial_number == cmd->serial_number && !busy &&
	    elv_queue_empty(drive->queue) && HWGROUP(drive)->rq != scsi->pc->rq) {
		/*
		 * FIXME - not sure this condition can ever occur
		 */
		printk (KERN_ERR "ide-scsi: cmd aborted!\n");

		if (blk_sense_request(scsi->pc->rq))
			kfree(scsi->pc->buffer);
		kfree(scsi->pc->rq);
		kfree(scsi->pc);
		scsi->pc = NULL;

		ret = SUCCESS;
	}

ide_unlock:
	spin_unlock_irq(&ide_lock);
no_drive:
	if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
		printk (KERN_WARNING "ide-scsi: abort returns %s\n", ret == SUCCESS?"success":"failed");

	return ret;
}

static int idescsi_eh_reset (struct scsi_cmnd *cmd)
{
	struct request *req;
	idescsi_scsi_t *scsi  = scsihost_to_idescsi(cmd->device->host);
	ide_drive_t    *drive = scsi->drive;
	int             ready = 0;
	int             ret   = SUCCESS;

	/* In idescsi_eh_reset we forcefully remove the command from the ide subsystem and reset the device. */

	if (test_bit(IDESCSI_LOG_CMD, &scsi->log))
		printk (KERN_WARNING "ide-scsi: reset called for %lu\n", cmd->serial_number);

	if (!drive) {
		printk (KERN_WARNING "ide-scsi: Drive not set in idescsi_eh_reset\n");
		WARN_ON(1);
		return FAILED;
	}

	spin_lock_irq(cmd->device->host->host_lock);
	spin_lock(&ide_lock);

	if (!scsi->pc || (req = scsi->pc->rq) != HWGROUP(drive)->rq || !HWGROUP(drive)->handler) {
		printk (KERN_WARNING "ide-scsi: No active request in idescsi_eh_reset\n");
		spin_unlock(&ide_lock);
		spin_unlock_irq(cmd->device->host->host_lock);
		return FAILED;
	}

	/* kill current request */
	if (__blk_end_request(req, -EIO, 0))
		BUG();
	if (blk_sense_request(req))
		kfree(scsi->pc->buffer);
	kfree(scsi->pc);
	scsi->pc = NULL;
	kfree(req);

	/* now nuke the drive queue */
	while ((req = elv_next_request(drive->queue))) {
		if (__blk_end_request(req, -EIO, 0))
			BUG();
	}

	HWGROUP(drive)->rq = NULL;
	HWGROUP(drive)->handler = NULL;
	HWGROUP(drive)->busy = 1;		/* will set this to zero when ide reset finished */
	spin_unlock(&ide_lock);

	ide_do_reset(drive);

	/* ide_do_reset starts a polling handler which restarts itself every 50ms until the reset finishes */

	do {
		spin_unlock_irq(cmd->device->host->host_lock);
		msleep(50);
		spin_lock_irq(cmd->device->host->host_lock);
	} while ( HWGROUP(drive)->handler );

	ready = drive_is_ready(drive);
	HWGROUP(drive)->busy--;
	if (!ready) {
		printk (KERN_ERR "ide-scsi: reset failed!\n");
		ret = FAILED;
	}

	spin_unlock_irq(cmd->device->host->host_lock);
	return ret;
}

static int idescsi_bios(struct scsi_device *sdev, struct block_device *bdev,
		sector_t capacity, int *parm)
{
	idescsi_scsi_t *idescsi = scsihost_to_idescsi(sdev->host);
	ide_drive_t *drive = idescsi->drive;

	if (drive->bios_cyl && drive->bios_head && drive->bios_sect) {
		parm[0] = drive->bios_head;
		parm[1] = drive->bios_sect;
		parm[2] = drive->bios_cyl;
	}
	return 0;
}

static struct scsi_host_template idescsi_template = {
	.module			= THIS_MODULE,
	.name			= "idescsi",
	.info			= idescsi_info,
	.slave_configure        = idescsi_slave_configure,
	.ioctl			= idescsi_ioctl,
	.queuecommand		= idescsi_queue,
	.eh_abort_handler	= idescsi_eh_abort,
	.eh_host_reset_handler  = idescsi_eh_reset,
	.bios_param		= idescsi_bios,
	.can_queue		= 40,
	.this_id		= -1,
	.sg_tablesize		= 256,
	.cmd_per_lun		= 5,
	.max_sectors		= 128,
	.use_clustering		= DISABLE_CLUSTERING,
	.emulated		= 1,
	.proc_name		= "ide-scsi",
};

static int ide_scsi_probe(ide_drive_t *drive)
{
	idescsi_scsi_t *idescsi;
	struct Scsi_Host *host;
	struct gendisk *g;
	static int warned;
	int err = -ENOMEM;

	if (!warned && drive->media == ide_cdrom) {
		printk(KERN_WARNING "ide-scsi is deprecated for cd burning! Use ide-cd and give dev=/dev/hdX as device\n");
		warned = 1;
	}

	if (idescsi_nocd && drive->media == ide_cdrom)
		return -ENODEV;

	if (!strstr("ide-scsi", drive->driver_req) ||
	    !drive->present ||
	    drive->media == ide_disk ||
	    !(host = scsi_host_alloc(&idescsi_template,sizeof(idescsi_scsi_t))))
		return -ENODEV;

	g = alloc_disk(1 << PARTN_BITS);
	if (!g)
		goto out_host_put;

	ide_init_disk(g, drive);

	host->max_id = 1;

#if IDESCSI_DEBUG_LOG
	if (drive->id->last_lun)
		printk(KERN_NOTICE "%s: id->last_lun=%u\n", drive->name, drive->id->last_lun);
#endif
	if ((drive->id->last_lun & 0x7) != 7)
		host->max_lun = (drive->id->last_lun & 0x7) + 1;
	else
		host->max_lun = 1;

	drive->driver_data = host;
	idescsi = scsihost_to_idescsi(host);
	idescsi->drive = drive;
	idescsi->driver = &idescsi_driver;
	idescsi->host = host;
	idescsi->disk = g;
	g->private_data = &idescsi->driver;
	ide_proc_register_driver(drive, &idescsi_driver);
	err = 0;
	idescsi_setup(drive, idescsi);
	g->fops = &idescsi_ops;
	ide_register_region(g);
	err = scsi_add_host(host, &drive->gendev);
	if (!err) {
		scsi_scan_host(host);
		return 0;
	}
	/* fall through on error */
	ide_unregister_region(g);
	ide_proc_unregister_driver(drive, &idescsi_driver);

	put_disk(g);
out_host_put:
	scsi_host_put(host);
	return err;
}

static int __init init_idescsi_module(void)
{
	return driver_register(&idescsi_driver.gen_driver);
}

static void __exit exit_idescsi_module(void)
{
	driver_unregister(&idescsi_driver.gen_driver);
}

module_param(idescsi_nocd, int, 0600);
MODULE_PARM_DESC(idescsi_nocd, "Disable handling of CD-ROMs so they may be driven by ide-cd");
module_init(init_idescsi_module);
module_exit(exit_idescsi_module);
MODULE_LICENSE("GPL");