ide-tape.c 75.1 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
/*
2 3
 * IDE ATAPI streaming tape driver.
 *
4 5
 * Copyright (C) 1995-1999  Gadi Oxman <gadio@netvision.net.il>
 * Copyright (C) 2003-2005  Bartlomiej Zolnierkiewicz
Linus Torvalds's avatar
Linus Torvalds committed
6 7 8 9 10 11 12 13
 *
 * This driver was constructed as a student project in the software laboratory
 * of the faculty of electrical engineering in the Technion - Israel's
 * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
 *
 * It is hereby placed under the terms of the GNU general public license.
 * (See linux/COPYING).
 *
14 15
 * For a historical changelog see
 * Documentation/ide/ChangeLog.ide-tape.1995-2002
Linus Torvalds's avatar
Linus Torvalds committed
16 17
 */

18
#define IDETAPE_VERSION "1.20"
Linus Torvalds's avatar
Linus Torvalds committed
19 20 21 22 23 24 25 26 27

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
28
#include <linux/jiffies.h>
Linus Torvalds's avatar
Linus Torvalds committed
29 30 31 32 33 34 35 36 37
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/genhd.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/ide.h>
#include <linux/smp_lock.h>
#include <linux/completion.h>
#include <linux/bitops.h>
38
#include <linux/mutex.h>
39
#include <scsi/scsi.h>
Linus Torvalds's avatar
Linus Torvalds committed
40 41

#include <asm/byteorder.h>
42 43 44
#include <linux/irq.h>
#include <linux/uaccess.h>
#include <linux/io.h>
Linus Torvalds's avatar
Linus Torvalds committed
45 46 47
#include <asm/unaligned.h>
#include <linux/mtio.h>

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
enum {
	/* output errors only */
	DBG_ERR =		(1 << 0),
	/* output all sense key/asc */
	DBG_SENSE =		(1 << 1),
	/* info regarding all chrdev-related procedures */
	DBG_CHRDEV =		(1 << 2),
	/* all remaining procedures */
	DBG_PROCS =		(1 << 3),
	/* buffer alloc info (pc_stack & rq_stack) */
	DBG_PCRQ_STACK =	(1 << 4),
};

/* define to see debug info */
#define IDETAPE_DEBUG_LOG		0

#if IDETAPE_DEBUG_LOG
#define debug_log(lvl, fmt, args...)			\
{							\
	if (tape->debug_mask & lvl)			\
	printk(KERN_INFO "ide-tape: " fmt, ## args);	\
}
#else
#define debug_log(lvl, fmt, args...) do {} while (0)
#endif

Linus Torvalds's avatar
Linus Torvalds committed
74 75
/**************************** Tunable parameters *****************************/
/*
76 77
 * After each failed packet command we issue a request sense command and retry
 * the packet command IDETAPE_MAX_PC_RETRIES times.
Linus Torvalds's avatar
Linus Torvalds committed
78
 *
79
 * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
Linus Torvalds's avatar
Linus Torvalds committed
80 81 82 83
 */
#define IDETAPE_MAX_PC_RETRIES		3

/*
84 85
 * With each packet command, we allocate a buffer of IDETAPE_PC_BUFFER_SIZE
 * bytes. This is used for several packet commands (Not for READ/WRITE commands)
Linus Torvalds's avatar
Linus Torvalds committed
86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
 */
#define IDETAPE_PC_BUFFER_SIZE		256

/*
 *	In various places in the driver, we need to allocate storage
 *	for packet commands and requests, which will remain valid while
 *	we leave the driver to wait for an interrupt or a timeout event.
 */
#define IDETAPE_PC_STACK		(10 + IDETAPE_MAX_PC_RETRIES)

/*
 * Some drives (for example, Seagate STT3401A Travan) require a very long
 * timeout, because they don't return an interrupt or clear their busy bit
 * until after the command completes (even retension commands).
 */
#define IDETAPE_WAIT_CMD		(900*HZ)

/*
104 105 106 107
 * The following parameter is used to select the point in the internal tape fifo
 * in which we will start to refill the buffer. Decreasing the following
 * parameter will improve the system's latency and interactive response, while
 * using a high value might improve system throughput.
Linus Torvalds's avatar
Linus Torvalds committed
108
 */
109
#define IDETAPE_FIFO_THRESHOLD		2
Linus Torvalds's avatar
Linus Torvalds committed
110 111

/*
112
 * DSC polling parameters.
Linus Torvalds's avatar
Linus Torvalds committed
113
 *
114 115
 * Polling for DSC (a single bit in the status register) is a very important
 * function in ide-tape. There are two cases in which we poll for DSC:
Linus Torvalds's avatar
Linus Torvalds committed
116
 *
117 118 119 120 121
 * 1. Before a read/write packet command, to ensure that we can transfer data
 * from/to the tape's data buffers, without causing an actual media access.
 * In case the tape is not ready yet, we take out our request from the device
 * request queue, so that ide.c could service requests from the other device
 * on the same interface in the meantime.
Linus Torvalds's avatar
Linus Torvalds committed
122
 *
123 124 125 126 127 128 129 130
 * 2. After the successful initialization of a "media access packet command",
 * which is a command that can take a long time to complete (the interval can
 * range from several seconds to even an hour). Again, we postpone our request
 * in the middle to free the bus for the other device. The polling frequency
 * here should be lower than the read/write frequency since those media access
 * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
 * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
 * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
Linus Torvalds's avatar
Linus Torvalds committed
131
 *
132 133
 * We also set a timeout for the timer, in case something goes wrong. The
 * timeout should be longer then the maximum execution time of a tape operation.
Linus Torvalds's avatar
Linus Torvalds committed
134
 */
135 136

/* DSC timings. */
Linus Torvalds's avatar
Linus Torvalds committed
137 138 139 140 141 142 143 144 145 146
#define IDETAPE_DSC_RW_MIN		5*HZ/100	/* 50 msec */
#define IDETAPE_DSC_RW_MAX		40*HZ/100	/* 400 msec */
#define IDETAPE_DSC_RW_TIMEOUT		2*60*HZ		/* 2 minutes */
#define IDETAPE_DSC_MA_FAST		2*HZ		/* 2 seconds */
#define IDETAPE_DSC_MA_THRESHOLD	5*60*HZ		/* 5 minutes */
#define IDETAPE_DSC_MA_SLOW		30*HZ		/* 30 seconds */
#define IDETAPE_DSC_MA_TIMEOUT		2*60*60*HZ	/* 2 hours */

/*************************** End of tunable parameters ***********************/

147 148 149 150 151 152
/* tape directions */
enum {
	IDETAPE_DIR_NONE  = (1 << 0),
	IDETAPE_DIR_READ  = (1 << 1),
	IDETAPE_DIR_WRITE = (1 << 2),
};
Linus Torvalds's avatar
Linus Torvalds committed
153 154

struct idetape_bh {
155
	u32 b_size;
Linus Torvalds's avatar
Linus Torvalds committed
156 157 158 159 160
	atomic_t b_count;
	struct idetape_bh *b_reqnext;
	char *b_data;
};

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
/* Tape door status */
#define DOOR_UNLOCKED			0
#define DOOR_LOCKED			1
#define DOOR_EXPLICITLY_LOCKED		2

/* Some defines for the SPACE command */
#define IDETAPE_SPACE_OVER_FILEMARK	1
#define IDETAPE_SPACE_TO_EOD		3

/* Some defines for the LOAD UNLOAD command */
#define IDETAPE_LU_LOAD_MASK		1
#define IDETAPE_LU_RETENSION_MASK	2
#define IDETAPE_LU_EOT_MASK		4

/*
 * Special requests for our block device strategy routine.
 *
 * In order to service a character device command, we add special requests to
 * the tail of our block device request queue and wait for their completion.
 */

enum {
	REQ_IDETAPE_PC1		= (1 << 0), /* packet command (first stage) */
	REQ_IDETAPE_PC2		= (1 << 1), /* packet command (second stage) */
	REQ_IDETAPE_READ	= (1 << 2),
	REQ_IDETAPE_WRITE	= (1 << 3),
};

/* Error codes returned in rq->errors to the higher part of the driver. */
#define IDETAPE_ERROR_GENERAL		101
#define IDETAPE_ERROR_FILEMARK		102
#define IDETAPE_ERROR_EOD		103

/* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
#define IDETAPE_BLOCK_DESCRIPTOR	0
#define IDETAPE_CAPABILITIES_PAGE	0x2a

Linus Torvalds's avatar
Linus Torvalds committed
198
/*
199 200
 * Most of our global data which we need to save even as we leave the driver due
 * to an interrupt or a timer event is stored in the struct defined below.
Linus Torvalds's avatar
Linus Torvalds committed
201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223
 */
typedef struct ide_tape_obj {
	ide_drive_t	*drive;
	ide_driver_t	*driver;
	struct gendisk	*disk;
	struct kref	kref;

	/*
	 *	Since a typical character device operation requires more
	 *	than one packet command, we provide here enough memory
	 *	for the maximum of interconnected packet commands.
	 *	The packet commands are stored in the circular array pc_stack.
	 *	pc_stack_index points to the last used entry, and warps around
	 *	to the start when we get to the last array entry.
	 *
	 *	pc points to the current processed packet command.
	 *
	 *	failed_pc points to the last failed packet command, or contains
	 *	NULL if we do not need to retry any packet command. This is
	 *	required since an additional packet command is needed before the
	 *	retry, to get detailed information on what went wrong.
	 */
	/* Current packet command */
224
	struct ide_atapi_pc *pc;
Linus Torvalds's avatar
Linus Torvalds committed
225
	/* Last failed packet command */
226
	struct ide_atapi_pc *failed_pc;
Linus Torvalds's avatar
Linus Torvalds committed
227
	/* Packet command stack */
228
	struct ide_atapi_pc pc_stack[IDETAPE_PC_STACK];
Linus Torvalds's avatar
Linus Torvalds committed
229 230 231 232 233 234 235
	/* Next free packet command storage space */
	int pc_stack_index;
	struct request rq_stack[IDETAPE_PC_STACK];
	/* We implement a circular array */
	int rq_stack_index;

	/*
236
	 * DSC polling variables.
Linus Torvalds's avatar
Linus Torvalds committed
237
	 *
238 239 240
	 * While polling for DSC we use postponed_rq to postpone the current
	 * request so that ide.c will be able to service pending requests on the
	 * other device. Note that at most we will have only one DSC (usually
241
	 * data transfer) request in the device request queue.
Linus Torvalds's avatar
Linus Torvalds committed
242 243 244 245 246 247 248
	 */
	struct request *postponed_rq;
	/* The time in which we started polling for DSC */
	unsigned long dsc_polling_start;
	/* Timer used to poll for dsc */
	struct timer_list dsc_timer;
	/* Read/Write dsc polling frequency */
249 250
	unsigned long best_dsc_rw_freq;
	unsigned long dsc_poll_freq;
Linus Torvalds's avatar
Linus Torvalds committed
251 252
	unsigned long dsc_timeout;

253
	/* Read position information */
Linus Torvalds's avatar
Linus Torvalds committed
254 255
	u8 partition;
	/* Current block */
256
	unsigned int first_frame;
Linus Torvalds's avatar
Linus Torvalds committed
257

258
	/* Last error information */
Linus Torvalds's avatar
Linus Torvalds committed
259 260
	u8 sense_key, asc, ascq;

261
	/* Character device operation */
Linus Torvalds's avatar
Linus Torvalds committed
262 263 264 265
	unsigned int minor;
	/* device name */
	char name[4];
	/* Current character device data transfer direction */
266
	u8 chrdev_dir;
Linus Torvalds's avatar
Linus Torvalds committed
267

268 269
	/* tape block size, usually 512 or 1024 bytes */
	unsigned short blk_size;
Linus Torvalds's avatar
Linus Torvalds committed
270
	int user_bs_factor;
271

Linus Torvalds's avatar
Linus Torvalds committed
272
	/* Copy of the tape's Capabilities and Mechanical Page */
273
	u8 caps[20];
Linus Torvalds's avatar
Linus Torvalds committed
274 275

	/*
276
	 * Active data transfer request parameters.
Linus Torvalds's avatar
Linus Torvalds committed
277
	 *
278 279 280
	 * At most, there is only one ide-tape originated data transfer request
	 * in the device request queue. This allows ide.c to easily service
	 * requests from the other device when we postpone our active request.
Linus Torvalds's avatar
Linus Torvalds committed
281
	 */
282

283
	/* Data buffer size chosen based on the tape's recommendation */
284
	int buffer_size;
285 286
	/* merge buffer */
	struct idetape_bh *merge_bh;
287 288
	/* size of the merge buffer */
	int merge_bh_size;
289
	/* pointer to current buffer head within the merge buffer */
Linus Torvalds's avatar
Linus Torvalds committed
290 291 292
	struct idetape_bh *bh;
	char *b_data;
	int b_count;
293

294
	int pages_per_buffer;
Linus Torvalds's avatar
Linus Torvalds committed
295 296 297 298
	/* Wasted space in each stage */
	int excess_bh_size;

	/* protects the ide-tape queue */
299
	spinlock_t lock;
Linus Torvalds's avatar
Linus Torvalds committed
300

301
	/* Measures average tape speed */
Linus Torvalds's avatar
Linus Torvalds committed
302 303 304 305 306 307 308 309 310 311 312
	unsigned long avg_time;
	int avg_size;
	int avg_speed;

	/* the door is currently locked */
	int door_locked;
	/* the tape hardware is write protected */
	char drv_write_prot;
	/* the tape is write protected (hardware or opened as read-only) */
	char write_prot;

313
	u32 debug_mask;
Linus Torvalds's avatar
Linus Torvalds committed
314 315
} idetape_tape_t;

316
static DEFINE_MUTEX(idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
317

318 319
static struct class *idetape_sysfs_class;

Linus Torvalds's avatar
Linus Torvalds committed
320 321 322 323 324
#define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)

#define ide_tape_g(disk) \
	container_of((disk)->private_data, struct ide_tape_obj, driver)

325 326
static void ide_tape_release(struct kref *);

Linus Torvalds's avatar
Linus Torvalds committed
327 328 329 330
static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
{
	struct ide_tape_obj *tape = NULL;

331
	mutex_lock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
332
	tape = ide_tape_g(disk);
333
	if (tape) {
334
		if (ide_device_get(tape->drive))
335
			tape = NULL;
336 337
		else
			kref_get(&tape->kref);
338
	}
339
	mutex_unlock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
340 341 342 343 344
	return tape;
}

static void ide_tape_put(struct ide_tape_obj *tape)
{
345 346
	ide_drive_t *drive = tape->drive;

347
	mutex_lock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
348
	kref_put(&tape->kref, ide_tape_release);
349
	ide_device_put(drive);
350
	mutex_unlock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
351 352 353
}

/*
354 355
 * The variables below are used for the character device interface. Additional
 * state variables are defined in our ide_drive_t structure.
Linus Torvalds's avatar
Linus Torvalds committed
356
 */
357
static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
Linus Torvalds's avatar
Linus Torvalds committed
358 359 360 361 362 363 364

#define ide_tape_f(file) ((file)->private_data)

static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
{
	struct ide_tape_obj *tape = NULL;

365
	mutex_lock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
366 367 368
	tape = idetape_devs[i];
	if (tape)
		kref_get(&tape->kref);
369
	mutex_unlock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
370 371 372
	return tape;
}

373
static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
374
				  unsigned int bcount)
Linus Torvalds's avatar
Linus Torvalds committed
375 376 377 378 379 380 381 382
{
	struct idetape_bh *bh = pc->bh;
	int count;

	while (bcount) {
		if (bh == NULL) {
			printk(KERN_ERR "ide-tape: bh == NULL in "
				"idetape_input_buffers\n");
383
			ide_pad_transfer(drive, 0, bcount);
Linus Torvalds's avatar
Linus Torvalds committed
384 385
			return;
		}
386 387 388
		count = min(
			(unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
			bcount);
389
		drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
390
					atomic_read(&bh->b_count), count);
Linus Torvalds's avatar
Linus Torvalds committed
391 392 393 394 395 396 397 398 399 400 401
		bcount -= count;
		atomic_add(count, &bh->b_count);
		if (atomic_read(&bh->b_count) == bh->b_size) {
			bh = bh->b_reqnext;
			if (bh)
				atomic_set(&bh->b_count, 0);
		}
	}
	pc->bh = bh;
}

402
static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
403
				   unsigned int bcount)
Linus Torvalds's avatar
Linus Torvalds committed
404 405 406 407 408 409
{
	struct idetape_bh *bh = pc->bh;
	int count;

	while (bcount) {
		if (bh == NULL) {
410 411
			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
					__func__);
Linus Torvalds's avatar
Linus Torvalds committed
412 413 414
			return;
		}
		count = min((unsigned int)pc->b_count, (unsigned int)bcount);
415
		drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
Linus Torvalds's avatar
Linus Torvalds committed
416 417 418 419
		bcount -= count;
		pc->b_data += count;
		pc->b_count -= count;
		if (!pc->b_count) {
420 421
			bh = bh->b_reqnext;
			pc->bh = bh;
Linus Torvalds's avatar
Linus Torvalds committed
422 423 424 425 426 427 428 429
			if (bh) {
				pc->b_data = bh->b_data;
				pc->b_count = atomic_read(&bh->b_count);
			}
		}
	}
}

430
static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
Linus Torvalds's avatar
Linus Torvalds committed
431 432 433
{
	struct idetape_bh *bh = pc->bh;
	int count;
434
	unsigned int bcount = pc->xferred;
Linus Torvalds's avatar
Linus Torvalds committed
435

436
	if (pc->flags & PC_FLAG_WRITING)
Linus Torvalds's avatar
Linus Torvalds committed
437 438 439
		return;
	while (bcount) {
		if (bh == NULL) {
440 441
			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
					__func__);
Linus Torvalds's avatar
Linus Torvalds committed
442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458
			return;
		}
		count = min((unsigned int)bh->b_size, (unsigned int)bcount);
		atomic_set(&bh->b_count, count);
		if (atomic_read(&bh->b_count) == bh->b_size)
			bh = bh->b_reqnext;
		bcount -= count;
	}
	pc->bh = bh;
}

/*
 *	idetape_next_pc_storage returns a pointer to a place in which we can
 *	safely store a packet command, even though we intend to leave the
 *	driver. A storage space for a maximum of IDETAPE_PC_STACK packet
 *	commands is allocated at initialization time.
 */
459
static struct ide_atapi_pc *idetape_next_pc_storage(ide_drive_t *drive)
Linus Torvalds's avatar
Linus Torvalds committed
460 461 462
{
	idetape_tape_t *tape = drive->driver_data;

463 464
	debug_log(DBG_PCRQ_STACK, "pc_stack_index=%d\n", tape->pc_stack_index);

Linus Torvalds's avatar
Linus Torvalds committed
465
	if (tape->pc_stack_index == IDETAPE_PC_STACK)
466
		tape->pc_stack_index = 0;
Linus Torvalds's avatar
Linus Torvalds committed
467 468 469 470 471 472 473 474
	return (&tape->pc_stack[tape->pc_stack_index++]);
}

/*
 *	idetape_next_rq_storage is used along with idetape_next_pc_storage.
 *	Since we queue packet commands in the request queue, we need to
 *	allocate a request, along with the allocation of a packet command.
 */
475

Linus Torvalds's avatar
Linus Torvalds committed
476 477 478 479 480 481
/**************************************************************
 *                                                            *
 *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
 *  followed later on by kfree().   -ml                       *
 *                                                            *
 **************************************************************/
482 483

static struct request *idetape_next_rq_storage(ide_drive_t *drive)
Linus Torvalds's avatar
Linus Torvalds committed
484 485 486
{
	idetape_tape_t *tape = drive->driver_data;

487 488
	debug_log(DBG_PCRQ_STACK, "rq_stack_index=%d\n", tape->rq_stack_index);

Linus Torvalds's avatar
Linus Torvalds committed
489
	if (tape->rq_stack_index == IDETAPE_PC_STACK)
490
		tape->rq_stack_index = 0;
Linus Torvalds's avatar
Linus Torvalds committed
491 492 493 494
	return (&tape->rq_stack[tape->rq_stack_index++]);
}

/*
495 496
 * called on each failed packet command retry to analyze the request sense. We
 * currently do not utilize this information.
Linus Torvalds's avatar
Linus Torvalds committed
497
 */
498
static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
Linus Torvalds's avatar
Linus Torvalds committed
499 500
{
	idetape_tape_t *tape = drive->driver_data;
501
	struct ide_atapi_pc *pc = tape->failed_pc;
Linus Torvalds's avatar
Linus Torvalds committed
502

503 504 505
	tape->sense_key = sense[2] & 0xF;
	tape->asc       = sense[12];
	tape->ascq      = sense[13];
506 507 508

	debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
		 pc->c[0], tape->sense_key, tape->asc, tape->ascq);
Linus Torvalds's avatar
Linus Torvalds committed
509

510
	/* Correct pc->xferred by asking the tape.	 */
511
	if (pc->flags & PC_FLAG_DMA_ERROR) {
512
		pc->xferred = pc->req_xfer -
513
			tape->blk_size *
514
			get_unaligned_be32(&sense[3]);
515
		idetape_update_buffers(drive, pc);
Linus Torvalds's avatar
Linus Torvalds committed
516 517 518 519 520 521 522
	}

	/*
	 * If error was the result of a zero-length read or write command,
	 * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
	 * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
	 */
523
	if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
524 525 526
	    /* length == 0 */
	    && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
		if (tape->sense_key == 5) {
Linus Torvalds's avatar
Linus Torvalds committed
527 528 529
			/* don't report an error, everything's ok */
			pc->error = 0;
			/* don't retry read/write */
530
			pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
531 532
		}
	}
533
	if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
Linus Torvalds's avatar
Linus Torvalds committed
534
		pc->error = IDETAPE_ERROR_FILEMARK;
535
		pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
536
	}
537
	if (pc->c[0] == WRITE_6) {
538 539
		if ((sense[2] & 0x40) || (tape->sense_key == 0xd
		     && tape->asc == 0x0 && tape->ascq == 0x2)) {
Linus Torvalds's avatar
Linus Torvalds committed
540
			pc->error = IDETAPE_ERROR_EOD;
541
			pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
542 543
		}
	}
544
	if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
545
		if (tape->sense_key == 8) {
Linus Torvalds's avatar
Linus Torvalds committed
546
			pc->error = IDETAPE_ERROR_EOD;
547
			pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
548
		}
549
		if (!(pc->flags & PC_FLAG_ABORT) &&
550
		    pc->xferred)
Linus Torvalds's avatar
Linus Torvalds committed
551 552 553 554
			pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
	}
}

555
/* Free data buffers completely. */
556
static void ide_tape_kfree_buffer(idetape_tape_t *tape)
Linus Torvalds's avatar
Linus Torvalds committed
557
{
558
	struct idetape_bh *prev_bh, *bh = tape->merge_bh;
559 560 561 562 563 564 565 566 567 568 569 570

	while (bh) {
		u32 size = bh->b_size;

		while (size) {
			unsigned int order = fls(size >> PAGE_SHIFT)-1;

			if (bh->b_data)
				free_pages((unsigned long)bh->b_data, order);

			size &= (order-1);
			bh->b_data += (1 << order) * PAGE_SIZE;
Linus Torvalds's avatar
Linus Torvalds committed
571 572 573 574 575 576 577 578 579 580 581 582 583 584
		}
		prev_bh = bh;
		bh = bh->b_reqnext;
		kfree(prev_bh);
	}
}

static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
{
	struct request *rq = HWGROUP(drive)->rq;
	idetape_tape_t *tape = drive->driver_data;
	unsigned long flags;
	int error;

585
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
Linus Torvalds's avatar
Linus Torvalds committed
586 587

	switch (uptodate) {
588 589 590
	case 0:	error = IDETAPE_ERROR_GENERAL; break;
	case 1: error = 0; break;
	default: error = uptodate;
Linus Torvalds's avatar
Linus Torvalds committed
591 592 593 594 595
	}
	rq->errors = error;
	if (error)
		tape->failed_pc = NULL;

596 597 598 599 600
	if (!blk_special_request(rq)) {
		ide_end_request(drive, uptodate, nr_sects);
		return 0;
	}

601
	spin_lock_irqsave(&tape->lock, flags);
Linus Torvalds's avatar
Linus Torvalds committed
602 603 604

	ide_end_drive_cmd(drive, 0, 0);

605
	spin_unlock_irqrestore(&tape->lock, flags);
Linus Torvalds's avatar
Linus Torvalds committed
606 607 608
	return 0;
}

609
static void ide_tape_callback(ide_drive_t *drive)
Linus Torvalds's avatar
Linus Torvalds committed
610 611
{
	idetape_tape_t *tape = drive->driver_data;
612 613
	struct ide_atapi_pc *pc = tape->pc;
	int uptodate = pc->error ? 0 : 1;
Linus Torvalds's avatar
Linus Torvalds committed
614

615 616
	debug_log(DBG_PROCS, "Enter %s\n", __func__);

617 618 619
	if (tape->failed_pc == pc)
		tape->failed_pc = NULL;

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
	if (pc->c[0] == REQUEST_SENSE) {
		if (uptodate)
			idetape_analyze_error(drive, pc->buf);
		else
			printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
					"itself - Aborting request!\n");
	} else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
		struct request *rq = drive->hwif->hwgroup->rq;
		int blocks = pc->xferred / tape->blk_size;

		tape->avg_size += blocks * tape->blk_size;

		if (time_after_eq(jiffies, tape->avg_time + HZ)) {
			tape->avg_speed = tape->avg_size * HZ /
				(jiffies - tape->avg_time) / 1024;
			tape->avg_size = 0;
			tape->avg_time = jiffies;
		}

		tape->first_frame += blocks;
		rq->current_nr_sectors -= blocks;

		if (pc->error)
			uptodate = pc->error;
	} else if (pc->c[0] == READ_POSITION && uptodate) {
		u8 *readpos = tape->pc->buf;

		debug_log(DBG_SENSE, "BOP - %s\n",
				(readpos[0] & 0x80) ? "Yes" : "No");
		debug_log(DBG_SENSE, "EOP - %s\n",
				(readpos[0] & 0x40) ? "Yes" : "No");

		if (readpos[0] & 0x4) {
			printk(KERN_INFO "ide-tape: Block location is unknown"
					 "to the tape\n");
655
			clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
656 657 658
			uptodate = 0;
		} else {
			debug_log(DBG_SENSE, "Block Location - %u\n",
659
					be32_to_cpup((__be32 *)&readpos[4]));
660 661

			tape->partition = readpos[1];
662
			tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
663
			set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
664
		}
Linus Torvalds's avatar
Linus Torvalds committed
665
	}
666 667

	idetape_end_request(drive, uptodate, 0);
Linus Torvalds's avatar
Linus Torvalds committed
668 669
}

670 671 672 673 674 675 676 677 678 679
static void idetape_init_pc(struct ide_atapi_pc *pc)
{
	memset(pc->c, 0, 12);
	pc->retries = 0;
	pc->flags = 0;
	pc->req_xfer = 0;
	pc->buf = pc->pc_buf;
	pc->buf_size = IDETAPE_PC_BUFFER_SIZE;
	pc->bh = NULL;
	pc->b_data = NULL;
Linus Torvalds's avatar
Linus Torvalds committed
680 681
}

682
static void idetape_create_request_sense_cmd(struct ide_atapi_pc *pc)
Linus Torvalds's avatar
Linus Torvalds committed
683
{
684
	idetape_init_pc(pc);
685
	pc->c[0] = REQUEST_SENSE;
Linus Torvalds's avatar
Linus Torvalds committed
686
	pc->c[4] = 20;
687
	pc->req_xfer = 20;
Linus Torvalds's avatar
Linus Torvalds committed
688 689 690 691
}

static void idetape_init_rq(struct request *rq, u8 cmd)
{
692
	blk_rq_init(NULL, rq);
693
	rq->cmd_type = REQ_TYPE_SPECIAL;
694
	rq->cmd[13] = cmd;
Linus Torvalds's avatar
Linus Torvalds committed
695 696 697
}

/*
698 699 700 701 702
 * Generate a new packet command request in front of the request queue, before
 * the current request, so that it will be processed immediately, on the next
 * pass through the driver. The function below is called from the request
 * handling part of the driver (the "bottom" part). Safe storage for the request
 * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
Linus Torvalds's avatar
Linus Torvalds committed
703
 *
704 705 706
 * Memory for those requests is pre-allocated at initialization time, and is
 * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
 * the maximum possible number of inter-dependent packet commands.
Linus Torvalds's avatar
Linus Torvalds committed
707
 *
708 709 710
 * The higher level of the driver - The ioctl handler and the character device
 * handling functions should queue request to the lower level part and wait for
 * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
Linus Torvalds's avatar
Linus Torvalds committed
711
 */
712
static void idetape_queue_pc_head(ide_drive_t *drive, struct ide_atapi_pc *pc,
713
				  struct request *rq)
Linus Torvalds's avatar
Linus Torvalds committed
714 715 716 717
{
	struct ide_tape_obj *tape = drive->driver_data;

	idetape_init_rq(rq, REQ_IDETAPE_PC1);
718
	rq->cmd_flags |= REQ_PREEMPT;
Linus Torvalds's avatar
Linus Torvalds committed
719 720
	rq->buffer = (char *) pc;
	rq->rq_disk = tape->disk;
721
	memcpy(rq->cmd, pc->c, 12);
722
	ide_do_drive_cmd(drive, rq);
Linus Torvalds's avatar
Linus Torvalds committed
723 724 725 726 727 728 729
}

/*
 *	idetape_retry_pc is called when an error was detected during the
 *	last packet command. We queue a request sense packet command in
 *	the head of the request list.
 */
730
static void idetape_retry_pc(ide_drive_t *drive)
Linus Torvalds's avatar
Linus Torvalds committed
731
{
732
	struct ide_atapi_pc *pc;
Linus Torvalds's avatar
Linus Torvalds committed
733 734
	struct request *rq;

735
	(void)ide_read_error(drive);
Linus Torvalds's avatar
Linus Torvalds committed
736 737 738
	pc = idetape_next_pc_storage(drive);
	rq = idetape_next_rq_storage(drive);
	idetape_create_request_sense_cmd(pc);
739
	set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
Linus Torvalds's avatar
Linus Torvalds committed
740 741 742 743
	idetape_queue_pc_head(drive, pc, rq);
}

/*
744 745
 * Postpone the current request so that ide.c will be able to service requests
 * from another device on the same hwgroup while we are polling for DSC.
Linus Torvalds's avatar
Linus Torvalds committed
746
 */
747
static void idetape_postpone_request(ide_drive_t *drive)
Linus Torvalds's avatar
Linus Torvalds committed
748 749 750
{
	idetape_tape_t *tape = drive->driver_data;

751 752
	debug_log(DBG_PROCS, "Enter %s\n", __func__);

Linus Torvalds's avatar
Linus Torvalds committed
753
	tape->postponed_rq = HWGROUP(drive)->rq;
754
	ide_stall_queue(drive, tape->dsc_poll_freq);
Linus Torvalds's avatar
Linus Torvalds committed
755 756
}

757 758 759 760 761 762 763 764 765 766 767 768
static void ide_tape_handle_dsc(ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;

	/* Media access command */
	tape->dsc_polling_start = jiffies;
	tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
	tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
	/* Allow ide.c to handle other requests */
	idetape_postpone_request(drive);
}

769 770 771 772 773 774 775 776
static void ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
				unsigned int bcount, int write)
{
	if (write)
		idetape_output_buffers(drive, pc, bcount);
	else
		idetape_input_buffers(drive, pc, bcount);
}
777

Linus Torvalds's avatar
Linus Torvalds committed
778
/*
779 780 781 782
 * This is the usual interrupt handler which will be called during a packet
 * command. We will transfer some of the data (as requested by the drive) and
 * will re-point interrupt handler to us. When data transfer is finished, we
 * will act according to the algorithm described before
783
 * idetape_issue_pc.
Linus Torvalds's avatar
Linus Torvalds committed
784
 */
785
static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
Linus Torvalds's avatar
Linus Torvalds committed
786 787 788
{
	idetape_tape_t *tape = drive->driver_data;

789 790 791
	return ide_pc_intr(drive, tape->pc, idetape_pc_intr, IDETAPE_WAIT_CMD,
			   NULL, idetape_update_buffers, idetape_retry_pc,
			   ide_tape_handle_dsc, ide_tape_io_buffers);
Linus Torvalds's avatar
Linus Torvalds committed
792 793 794
}

/*
795
 * Packet Command Interface
Linus Torvalds's avatar
Linus Torvalds committed
796
 *
797 798 799
 * The current Packet Command is available in tape->pc, and will not change
 * until we finish handling it. Each packet command is associated with a
 * callback function that will be called when the command is finished.
Linus Torvalds's avatar
Linus Torvalds committed
800
 *
801
 * The handling will be done in three stages:
Linus Torvalds's avatar
Linus Torvalds committed
802
 *
803 804
 * 1. idetape_issue_pc will send the packet command to the drive, and will set
 * the interrupt handler to idetape_pc_intr.
Linus Torvalds's avatar
Linus Torvalds committed
805
 *
806 807
 * 2. On each interrupt, idetape_pc_intr will be called. This step will be
 * repeated until the device signals us that no more interrupts will be issued.
Linus Torvalds's avatar
Linus Torvalds committed
808
 *
809 810 811 812 813 814 815
 * 3. ATAPI Tape media access commands have immediate status with a delayed
 * process. In case of a successful initiation of a media access packet command,
 * the DSC bit will be set when the actual execution of the command is finished.
 * Since the tape drive will not issue an interrupt, we have to poll for this
 * event. In this case, we define the request as "low priority request" by
 * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
 * exit the driver.
Linus Torvalds's avatar
Linus Torvalds committed
816
 *
817 818
 * ide.c will then give higher priority to requests which originate from the
 * other device, until will change rq_status to RQ_ACTIVE.
Linus Torvalds's avatar
Linus Torvalds committed
819
 *
820
 * 4. When the packet command is finished, it will be checked for errors.
Linus Torvalds's avatar
Linus Torvalds committed
821
 *
822 823 824
 * 5. In case an error was found, we queue a request sense packet command in
 * front of the request queue and retry the operation up to
 * IDETAPE_MAX_PC_RETRIES times.
Linus Torvalds's avatar
Linus Torvalds committed
825
 *
826 827 828
 * 6. In case no error was found, or we decided to give up and not to retry
 * again, the callback function will be called and then we will handle the next
 * request.
Linus Torvalds's avatar
Linus Torvalds committed
829 830 831 832
 */
static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
{
	idetape_tape_t *tape = drive->driver_data;
833

834 835
	return ide_transfer_pc(drive, tape->pc, idetape_pc_intr,
			       IDETAPE_WAIT_CMD, NULL);
Linus Torvalds's avatar
Linus Torvalds committed
836 837
}

838 839
static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
		struct ide_atapi_pc *pc)
Linus Torvalds's avatar
Linus Torvalds committed
840 841 842
{
	idetape_tape_t *tape = drive->driver_data;

843 844
	if (tape->pc->c[0] == REQUEST_SENSE &&
	    pc->c[0] == REQUEST_SENSE) {
Linus Torvalds's avatar
Linus Torvalds committed
845 846 847 848
		printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
			"Two request sense in serial were issued\n");
	}

849
	if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
Linus Torvalds's avatar
Linus Torvalds committed
850 851 852 853 854
		tape->failed_pc = pc;
	/* Set the current packet command */
	tape->pc = pc;

	if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
855
		(pc->flags & PC_FLAG_ABORT)) {
Linus Torvalds's avatar
Linus Torvalds committed
856
		/*
857 858 859
		 * We will "abort" retrying a packet command in case legitimate
		 * error code was received (crossing a filemark, or end of the
		 * media, for example).
Linus Torvalds's avatar
Linus Torvalds committed
860
		 */
861
		if (!(pc->flags & PC_FLAG_ABORT)) {
862
			if (!(pc->c[0] == TEST_UNIT_READY &&
Linus Torvalds's avatar
Linus Torvalds committed
863 864 865 866 867 868 869 870 871 872 873 874 875
			      tape->sense_key == 2 && tape->asc == 4 &&
			     (tape->ascq == 1 || tape->ascq == 8))) {
				printk(KERN_ERR "ide-tape: %s: I/O error, "
						"pc = %2x, key = %2x, "
						"asc = %2x, ascq = %2x\n",
						tape->name, pc->c[0],
						tape->sense_key, tape->asc,
						tape->ascq);
			}
			/* Giving up */
			pc->error = IDETAPE_ERROR_GENERAL;
		}
		tape->failed_pc = NULL;
876
		drive->pc_callback(drive);
877
		return ide_stopped;
Linus Torvalds's avatar
Linus Torvalds committed
878
	}
879
	debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
Linus Torvalds's avatar
Linus Torvalds committed
880 881 882

	pc->retries++;

883 884
	return ide_issue_pc(drive, pc, idetape_transfer_pc,
			    IDETAPE_WAIT_CMD, NULL);
Linus Torvalds's avatar
Linus Torvalds committed
885 886
}

887
/* A mode sense command is used to "sense" tape parameters. */
888
static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
Linus Torvalds's avatar
Linus Torvalds committed
889 890
{
	idetape_init_pc(pc);
891
	pc->c[0] = MODE_SENSE;
Linus Torvalds's avatar
Linus Torvalds committed
892
	if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
893 894
		/* DBD = 1 - Don't return block descriptors */
		pc->c[1] = 8;
Linus Torvalds's avatar
Linus Torvalds committed
895 896 897 898 899 900 901 902 903
	pc->c[2] = page_code;
	/*
	 * Changed pc->c[3] to 0 (255 will at best return unused info).
	 *
	 * For SCSI this byte is defined as subpage instead of high byte
	 * of length and some IDE drives seem to interpret it this way
	 * and return an error when 255 is used.
	 */
	pc->c[3] = 0;
904 905
	/* We will just discard data in that case */
	pc->c[4] = 255;
Linus Torvalds's avatar
Linus Torvalds committed
906
	if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
907
		pc->req_xfer = 12;
Linus Torvalds's avatar
Linus Torvalds committed
908
	else if (page_code == IDETAPE_CAPABILITIES_PAGE)
909
		pc->req_xfer = 24;
Linus Torvalds's avatar
Linus Torvalds committed
910
	else
911
		pc->req_xfer = 50;
Linus Torvalds's avatar
Linus Torvalds committed
912 913
}

914
static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
Linus Torvalds's avatar
Linus Torvalds committed
915
{
916
	ide_hwif_t *hwif = drive->hwif;
Linus Torvalds's avatar
Linus Torvalds committed
917
	idetape_tape_t *tape = drive->driver_data;
918
	struct ide_atapi_pc *pc = tape->pc;
919
	u8 stat;
Linus Torvalds's avatar
Linus Torvalds committed
920

921
	stat = hwif->tp_ops->read_status(hwif);
922

923 924
	if (stat & SEEK_STAT) {
		if (stat & ERR_STAT) {
Linus Torvalds's avatar
Linus Torvalds committed
925
			/* Error detected */
926
			if (pc->c[0] != TEST_UNIT_READY)
Linus Torvalds's avatar
Linus Torvalds committed
927 928 929
				printk(KERN_ERR "ide-tape: %s: I/O error, ",
						tape->name);
			/* Retry operation */
930 931
			idetape_retry_pc(drive);
			return ide_stopped;
Linus Torvalds's avatar
Linus Torvalds committed
932 933 934 935 936 937
		}
		pc->error = 0;
	} else {
		pc->error = IDETAPE_ERROR_GENERAL;
		tape->failed_pc = NULL;
	}
938
	drive->pc_callback(drive);
Linus Torvalds's avatar
Linus Torvalds committed
939 940 941
	return ide_stopped;
}

942
static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
943 944
				   struct ide_atapi_pc *pc, struct request *rq,
				   u8 opcode)
Linus Torvalds's avatar
Linus Torvalds committed
945
{
946 947 948
	struct idetape_bh *bh = (struct idetape_bh *)rq->special;
	unsigned int length = rq->current_nr_sectors;

Linus Torvalds's avatar
Linus Torvalds committed
949
	idetape_init_pc(pc);
950
	put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
Linus Torvalds's avatar
Linus Torvalds committed
951 952
	pc->c[1] = 1;
	pc->bh = bh;
953 954 955
	pc->buf = NULL;
	pc->buf_size = length * tape->blk_size;
	pc->req_xfer = pc->buf_size;
956
	if (pc->req_xfer == tape->buffer_size)
957
		pc->flags |= PC_FLAG_DMA_OK;
Linus Torvalds's avatar
Linus Torvalds committed
958

959 960 961 962 963 964 965 966 967
	if (opcode == READ_6) {
		pc->c[0] = READ_6;
		atomic_set(&bh->b_count, 0);
	} else if (opcode == WRITE_6) {
		pc->c[0] = WRITE_6;
		pc->flags |= PC_FLAG_WRITING;
		pc->b_data = bh->b_data;
		pc->b_count = atomic_read(&bh->b_count);
	}
968 969

	memcpy(rq->cmd, pc->c, 12);
Linus Torvalds's avatar
Linus Torvalds committed
970 971 972 973 974
}

static ide_startstop_t idetape_do_request(ide_drive_t *drive,
					  struct request *rq, sector_t block)
{
975
	ide_hwif_t *hwif = drive->hwif;
Linus Torvalds's avatar
Linus Torvalds committed
976
	idetape_tape_t *tape = drive->driver_data;
977
	struct ide_atapi_pc *pc = NULL;
Linus Torvalds's avatar
Linus Torvalds committed
978
	struct request *postponed_rq = tape->postponed_rq;
979
	u8 stat;
Linus Torvalds's avatar
Linus Torvalds committed
980

981 982
	debug_log(DBG_SENSE, "sector: %ld, nr_sectors: %ld,"
			" current_nr_sectors: %d\n",
Linus Torvalds's avatar
Linus Torvalds committed
983 984
			rq->sector, rq->nr_sectors, rq->current_nr_sectors);

985
	if (!blk_special_request(rq)) {
986
		/* We do not support buffer cache originated requests. */
Linus Torvalds's avatar
Linus Torvalds committed
987
		printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
988
			"request queue (%d)\n", drive->name, rq->cmd_type);
Linus Torvalds's avatar
Linus Torvalds committed
989 990 991 992
		ide_end_request(drive, 0, 0);
		return ide_stopped;
	}

993
	/* Retry a failed packet command */
994 995 996 997
	if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE) {
		pc = tape->failed_pc;
		goto out;
	}
998

Linus Torvalds's avatar
Linus Torvalds committed
999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012
	if (postponed_rq != NULL)
		if (rq != postponed_rq) {
			printk(KERN_ERR "ide-tape: ide-tape.c bug - "
					"Two DSC requests were queued\n");
			idetape_end_request(drive, 0, 0);
			return ide_stopped;
		}

	tape->postponed_rq = NULL;

	/*
	 * If the tape is still busy, postpone our request and service
	 * the other device meanwhile.
	 */
1013
	stat = hwif->tp_ops->read_status(hwif);
Linus Torvalds's avatar
Linus Torvalds committed
1014

1015
	if (!drive->dsc_overlap && !(rq->cmd[13] & REQ_IDETAPE_PC2))
1016
		set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
Linus Torvalds's avatar
Linus Torvalds committed
1017 1018

	if (drive->post_reset == 1) {
1019
		set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
Linus Torvalds's avatar
Linus Torvalds committed
1020 1021 1022
		drive->post_reset = 0;
	}