ide-tape.c 66.7 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 19
#define DRV_NAME "ide-tape"

20
#define IDETAPE_VERSION "1.20"
Linus Torvalds's avatar
Linus Torvalds committed
21 22 23 24 25 26 27 28 29

#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>
30
#include <linux/jiffies.h>
Linus Torvalds's avatar
Linus Torvalds committed
31 32 33 34 35 36 37 38 39
#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>
40
#include <linux/mutex.h>
41
#include <scsi/scsi.h>
Linus Torvalds's avatar
Linus Torvalds committed
42 43

#include <asm/byteorder.h>
44 45 46
#include <linux/irq.h>
#include <linux/uaccess.h>
#include <linux/io.h>
Linus Torvalds's avatar
Linus Torvalds committed
47 48 49
#include <asm/unaligned.h>
#include <linux/mtio.h>

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),
};

/* 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 86 87
 * 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
88
 */
89
#define IDETAPE_FIFO_THRESHOLD		2
Linus Torvalds's avatar
Linus Torvalds committed
90 91

/*
92
 * DSC polling parameters.
Linus Torvalds's avatar
Linus Torvalds committed
93
 *
94 95
 * 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
96
 *
97 98 99 100 101
 * 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
102
 *
103 104 105 106 107 108 109 110
 * 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
111
 *
112 113
 * 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
114
 */
115 116

/* DSC timings. */
Linus Torvalds's avatar
Linus Torvalds committed
117 118 119 120 121 122 123 124 125 126
#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 ***********************/

127 128 129 130 131 132
/* 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
133 134

struct idetape_bh {
135
	u32 b_size;
Linus Torvalds's avatar
Linus Torvalds committed
136 137 138 139 140
	atomic_t b_count;
	struct idetape_bh *b_reqnext;
	char *b_data;
};

141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163
/* 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

/* 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
164
/*
165 166
 * 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
167 168 169 170 171 172 173 174 175 176 177 178 179 180
 */
typedef struct ide_tape_obj {
	ide_drive_t	*drive;
	ide_driver_t	*driver;
	struct gendisk	*disk;
	struct kref	kref;

	/*
	 *	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.
	 */
	/* Last failed packet command */
181
	struct ide_atapi_pc *failed_pc;
182 183
	/* used by REQ_IDETAPE_{READ,WRITE} requests */
	struct ide_atapi_pc queued_pc;
184

Linus Torvalds's avatar
Linus Torvalds committed
185
	/*
186
	 * DSC polling variables.
Linus Torvalds's avatar
Linus Torvalds committed
187
	 *
188 189 190
	 * 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
191
	 * data transfer) request in the device request queue.
Linus Torvalds's avatar
Linus Torvalds committed
192 193 194 195 196 197 198
	 */
	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 */
199 200
	unsigned long best_dsc_rw_freq;
	unsigned long dsc_poll_freq;
Linus Torvalds's avatar
Linus Torvalds committed
201 202
	unsigned long dsc_timeout;

203
	/* Read position information */
Linus Torvalds's avatar
Linus Torvalds committed
204 205
	u8 partition;
	/* Current block */
206
	unsigned int first_frame;
Linus Torvalds's avatar
Linus Torvalds committed
207

208
	/* Last error information */
Linus Torvalds's avatar
Linus Torvalds committed
209 210
	u8 sense_key, asc, ascq;

211
	/* Character device operation */
Linus Torvalds's avatar
Linus Torvalds committed
212 213 214 215
	unsigned int minor;
	/* device name */
	char name[4];
	/* Current character device data transfer direction */
216
	u8 chrdev_dir;
Linus Torvalds's avatar
Linus Torvalds committed
217

218 219
	/* tape block size, usually 512 or 1024 bytes */
	unsigned short blk_size;
Linus Torvalds's avatar
Linus Torvalds committed
220
	int user_bs_factor;
221

Linus Torvalds's avatar
Linus Torvalds committed
222
	/* Copy of the tape's Capabilities and Mechanical Page */
223
	u8 caps[20];
Linus Torvalds's avatar
Linus Torvalds committed
224 225

	/*
226
	 * Active data transfer request parameters.
Linus Torvalds's avatar
Linus Torvalds committed
227
	 *
228 229 230
	 * 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
231
	 */
232

233
	/* Data buffer size chosen based on the tape's recommendation */
234
	int buffer_size;
235 236
	/* merge buffer */
	struct idetape_bh *merge_bh;
237 238
	/* size of the merge buffer */
	int merge_bh_size;
239
	/* pointer to current buffer head within the merge buffer */
Linus Torvalds's avatar
Linus Torvalds committed
240 241 242
	struct idetape_bh *bh;
	char *b_data;
	int b_count;
243

244
	int pages_per_buffer;
Linus Torvalds's avatar
Linus Torvalds committed
245 246 247 248
	/* Wasted space in each stage */
	int excess_bh_size;

	/* protects the ide-tape queue */
249
	spinlock_t lock;
Linus Torvalds's avatar
Linus Torvalds committed
250

251
	/* Measures average tape speed */
Linus Torvalds's avatar
Linus Torvalds committed
252 253 254 255 256 257 258 259 260 261 262
	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;

263
	u32 debug_mask;
Linus Torvalds's avatar
Linus Torvalds committed
264 265
} idetape_tape_t;

266
static DEFINE_MUTEX(idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
267

268 269
static struct class *idetape_sysfs_class;

270 271
static void ide_tape_release(struct kref *);

Linus Torvalds's avatar
Linus Torvalds committed
272 273 274 275
static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
{
	struct ide_tape_obj *tape = NULL;

276
	mutex_lock(&idetape_ref_mutex);
Borislav Petkov's avatar
Borislav Petkov committed
277
	tape = ide_drv_g(disk, ide_tape_obj);
278
	if (tape) {
279
		if (ide_device_get(tape->drive))
280
			tape = NULL;
281 282
		else
			kref_get(&tape->kref);
283
	}
284
	mutex_unlock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
285 286 287 288 289
	return tape;
}

static void ide_tape_put(struct ide_tape_obj *tape)
{
290 291
	ide_drive_t *drive = tape->drive;

292
	mutex_lock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
293
	kref_put(&tape->kref, ide_tape_release);
294
	ide_device_put(drive);
295
	mutex_unlock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
296 297 298
}

/*
299 300
 * 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
301
 */
302
static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
Linus Torvalds's avatar
Linus Torvalds committed
303 304 305 306 307

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

308
	mutex_lock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
309 310 311
	tape = idetape_devs[i];
	if (tape)
		kref_get(&tape->kref);
312
	mutex_unlock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
313 314 315
	return tape;
}

316
static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
317
				  unsigned int bcount)
Linus Torvalds's avatar
Linus Torvalds committed
318 319 320 321 322 323 324 325
{
	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");
326
			ide_pad_transfer(drive, 0, bcount);
Linus Torvalds's avatar
Linus Torvalds committed
327 328
			return;
		}
329 330 331
		count = min(
			(unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
			bcount);
332
		drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
333
					atomic_read(&bh->b_count), count);
Linus Torvalds's avatar
Linus Torvalds committed
334 335 336 337 338 339 340 341 342 343 344
		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;
}

345
static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
346
				   unsigned int bcount)
Linus Torvalds's avatar
Linus Torvalds committed
347 348 349 350 351 352
{
	struct idetape_bh *bh = pc->bh;
	int count;

	while (bcount) {
		if (bh == NULL) {
353 354
			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
					__func__);
Linus Torvalds's avatar
Linus Torvalds committed
355 356 357
			return;
		}
		count = min((unsigned int)pc->b_count, (unsigned int)bcount);
358
		drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
Linus Torvalds's avatar
Linus Torvalds committed
359 360 361 362
		bcount -= count;
		pc->b_data += count;
		pc->b_count -= count;
		if (!pc->b_count) {
363 364
			bh = bh->b_reqnext;
			pc->bh = bh;
Linus Torvalds's avatar
Linus Torvalds committed
365 366 367 368 369 370 371 372
			if (bh) {
				pc->b_data = bh->b_data;
				pc->b_count = atomic_read(&bh->b_count);
			}
		}
	}
}

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

379
	if (pc->flags & PC_FLAG_WRITING)
Linus Torvalds's avatar
Linus Torvalds committed
380 381 382
		return;
	while (bcount) {
		if (bh == NULL) {
383 384
			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
					__func__);
Linus Torvalds's avatar
Linus Torvalds committed
385 386 387 388 389 390 391 392 393 394 395 396
			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;
}

/*
397 398
 * 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
399
 */
400
static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
Linus Torvalds's avatar
Linus Torvalds committed
401 402
{
	idetape_tape_t *tape = drive->driver_data;
403
	struct ide_atapi_pc *pc = tape->failed_pc;
Linus Torvalds's avatar
Linus Torvalds committed
404

405 406 407
	tape->sense_key = sense[2] & 0xF;
	tape->asc       = sense[12];
	tape->ascq      = sense[13];
408 409 410

	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
411

412
	/* Correct pc->xferred by asking the tape.	 */
413
	if (pc->flags & PC_FLAG_DMA_ERROR) {
414
		pc->xferred = pc->req_xfer -
415
			tape->blk_size *
416
			get_unaligned_be32(&sense[3]);
417
		idetape_update_buffers(drive, pc);
Linus Torvalds's avatar
Linus Torvalds committed
418 419 420 421 422 423 424
	}

	/*
	 * 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.
	 */
425
	if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
426 427 428
	    /* 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
429 430 431
			/* don't report an error, everything's ok */
			pc->error = 0;
			/* don't retry read/write */
432
			pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
433 434
		}
	}
435
	if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
Linus Torvalds's avatar
Linus Torvalds committed
436
		pc->error = IDETAPE_ERROR_FILEMARK;
437
		pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
438
	}
439
	if (pc->c[0] == WRITE_6) {
440 441
		if ((sense[2] & 0x40) || (tape->sense_key == 0xd
		     && tape->asc == 0x0 && tape->ascq == 0x2)) {
Linus Torvalds's avatar
Linus Torvalds committed
442
			pc->error = IDETAPE_ERROR_EOD;
443
			pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
444 445
		}
	}
446
	if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
447
		if (tape->sense_key == 8) {
Linus Torvalds's avatar
Linus Torvalds committed
448
			pc->error = IDETAPE_ERROR_EOD;
449
			pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
450
		}
451
		if (!(pc->flags & PC_FLAG_ABORT) &&
452
		    pc->xferred)
Linus Torvalds's avatar
Linus Torvalds committed
453 454 455 456
			pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
	}
}

457
/* Free data buffers completely. */
458
static void ide_tape_kfree_buffer(idetape_tape_t *tape)
Linus Torvalds's avatar
Linus Torvalds committed
459
{
460
	struct idetape_bh *prev_bh, *bh = tape->merge_bh;
461 462 463 464 465 466 467 468 469 470 471 472

	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
473 474 475 476 477 478 479 480 481 482 483 484 485 486
		}
		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;

487
	debug_log(DBG_PROCS, "Enter %s\n", __func__);
Linus Torvalds's avatar
Linus Torvalds committed
488 489

	switch (uptodate) {
490 491 492
	case 0:	error = IDETAPE_ERROR_GENERAL; break;
	case 1: error = 0; break;
	default: error = uptodate;
Linus Torvalds's avatar
Linus Torvalds committed
493 494 495 496 497
	}
	rq->errors = error;
	if (error)
		tape->failed_pc = NULL;

498 499 500 501 502
	if (!blk_special_request(rq)) {
		ide_end_request(drive, uptodate, nr_sects);
		return 0;
	}

503
	spin_lock_irqsave(&tape->lock, flags);
Linus Torvalds's avatar
Linus Torvalds committed
504 505 506

	ide_end_drive_cmd(drive, 0, 0);

507
	spin_unlock_irqrestore(&tape->lock, flags);
Linus Torvalds's avatar
Linus Torvalds committed
508 509 510
	return 0;
}

511 512 513
static void ide_tape_handle_dsc(ide_drive_t *);

static void ide_tape_callback(ide_drive_t *drive, int dsc)
Linus Torvalds's avatar
Linus Torvalds committed
514 515
{
	idetape_tape_t *tape = drive->driver_data;
516
	struct ide_atapi_pc *pc = drive->pc;
517
	int uptodate = pc->error ? 0 : 1;
Linus Torvalds's avatar
Linus Torvalds committed
518

519 520
	debug_log(DBG_PROCS, "Enter %s\n", __func__);

521 522 523
	if (dsc)
		ide_tape_handle_dsc(drive);

524 525 526
	if (tape->failed_pc == pc)
		tape->failed_pc = NULL;

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
	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) {
552
		u8 *readpos = pc->buf;
553 554 555 556 557 558 559 560 561

		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");
562
			clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
563 564 565
			uptodate = 0;
		} else {
			debug_log(DBG_SENSE, "Block Location - %u\n",
566
					be32_to_cpup((__be32 *)&readpos[4]));
567 568

			tape->partition = readpos[1];
569
			tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
570
			set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
571
		}
Linus Torvalds's avatar
Linus Torvalds committed
572
	}
573 574

	idetape_end_request(drive, uptodate, 0);
Linus Torvalds's avatar
Linus Torvalds committed
575 576 577
}

/*
578 579
 * 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
580
 */
581
static void idetape_postpone_request(ide_drive_t *drive)
Linus Torvalds's avatar
Linus Torvalds committed
582 583 584
{
	idetape_tape_t *tape = drive->driver_data;

585 586
	debug_log(DBG_PROCS, "Enter %s\n", __func__);

Linus Torvalds's avatar
Linus Torvalds committed
587
	tape->postponed_rq = HWGROUP(drive)->rq;
588
	ide_stall_queue(drive, tape->dsc_poll_freq);
Linus Torvalds's avatar
Linus Torvalds committed
589 590
}

591 592 593 594 595 596 597 598 599 600 601 602
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);
}

603
static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
604 605 606 607 608 609
				unsigned int bcount, int write)
{
	if (write)
		idetape_output_buffers(drive, pc, bcount);
	else
		idetape_input_buffers(drive, pc, bcount);
610 611

	return bcount;
612
}
613

Linus Torvalds's avatar
Linus Torvalds committed
614
/*
615
 * Packet Command Interface
Linus Torvalds's avatar
Linus Torvalds committed
616
 *
617
 * The current Packet Command is available in drive->pc, and will not change
618 619
 * 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
620
 *
621
 * The handling will be done in three stages:
Linus Torvalds's avatar
Linus Torvalds committed
622
 *
623
 * 1. idetape_issue_pc will send the packet command to the drive, and will set
624
 * the interrupt handler to ide_pc_intr.
Linus Torvalds's avatar
Linus Torvalds committed
625
 *
626
 * 2. On each interrupt, ide_pc_intr will be called. This step will be
627
 * repeated until the device signals us that no more interrupts will be issued.
Linus Torvalds's avatar
Linus Torvalds committed
628
 *
629 630 631 632 633 634 635
 * 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
636
 *
637 638
 * 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
639
 *
640
 * 4. When the packet command is finished, it will be checked for errors.
Linus Torvalds's avatar
Linus Torvalds committed
641
 *
642 643 644
 * 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
645
 *
646 647 648
 * 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
649 650
 */

651 652
static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
		struct ide_atapi_pc *pc)
Linus Torvalds's avatar
Linus Torvalds committed
653 654 655
{
	idetape_tape_t *tape = drive->driver_data;

656
	if (drive->pc->c[0] == REQUEST_SENSE &&
657
	    pc->c[0] == REQUEST_SENSE) {
Linus Torvalds's avatar
Linus Torvalds committed
658 659 660 661
		printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
			"Two request sense in serial were issued\n");
	}

662
	if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
Linus Torvalds's avatar
Linus Torvalds committed
663
		tape->failed_pc = pc;
664

Linus Torvalds's avatar
Linus Torvalds committed
665
	/* Set the current packet command */
666
	drive->pc = pc;
Linus Torvalds's avatar
Linus Torvalds committed
667 668

	if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
669
		(pc->flags & PC_FLAG_ABORT)) {
Linus Torvalds's avatar
Linus Torvalds committed
670
		/*
671 672 673
		 * 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
674
		 */
675
		if (!(pc->flags & PC_FLAG_ABORT)) {
676
			if (!(pc->c[0] == TEST_UNIT_READY &&
Linus Torvalds's avatar
Linus Torvalds committed
677 678 679 680 681 682 683 684 685 686 687 688 689
			      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;
690
		drive->pc_callback(drive, 0);
691
		return ide_stopped;
Linus Torvalds's avatar
Linus Torvalds committed
692
	}
693
	debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
Linus Torvalds's avatar
Linus Torvalds committed
694 695 696

	pc->retries++;

697
	return ide_issue_pc(drive, WAIT_TAPE_CMD);
Linus Torvalds's avatar
Linus Torvalds committed
698 699
}

700
/* A mode sense command is used to "sense" tape parameters. */
701
static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
Linus Torvalds's avatar
Linus Torvalds committed
702
{
703
	ide_init_pc(pc);
704
	pc->c[0] = MODE_SENSE;
Linus Torvalds's avatar
Linus Torvalds committed
705
	if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
706 707
		/* DBD = 1 - Don't return block descriptors */
		pc->c[1] = 8;
Linus Torvalds's avatar
Linus Torvalds committed
708 709 710 711 712 713 714 715 716
	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;
717 718
	/* We will just discard data in that case */
	pc->c[4] = 255;
Linus Torvalds's avatar
Linus Torvalds committed
719
	if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
720
		pc->req_xfer = 12;
Linus Torvalds's avatar
Linus Torvalds committed
721
	else if (page_code == IDETAPE_CAPABILITIES_PAGE)
722
		pc->req_xfer = 24;
Linus Torvalds's avatar
Linus Torvalds committed
723
	else
724
		pc->req_xfer = 50;
Linus Torvalds's avatar
Linus Torvalds committed
725 726
}

727
static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
Linus Torvalds's avatar
Linus Torvalds committed
728
{
729
	ide_hwif_t *hwif = drive->hwif;
Linus Torvalds's avatar
Linus Torvalds committed
730
	idetape_tape_t *tape = drive->driver_data;
731
	struct ide_atapi_pc *pc = drive->pc;
732
	u8 stat;
Linus Torvalds's avatar
Linus Torvalds committed
733

734
	stat = hwif->tp_ops->read_status(hwif);
735

736 737
	if (stat & ATA_DSC) {
		if (stat & ATA_ERR) {
Linus Torvalds's avatar
Linus Torvalds committed
738
			/* Error detected */
739
			if (pc->c[0] != TEST_UNIT_READY)
Linus Torvalds's avatar
Linus Torvalds committed
740 741 742
				printk(KERN_ERR "ide-tape: %s: I/O error, ",
						tape->name);
			/* Retry operation */
743
			ide_retry_pc(drive, tape->disk);
744
			return ide_stopped;
Linus Torvalds's avatar
Linus Torvalds committed
745 746 747 748 749 750
		}
		pc->error = 0;
	} else {
		pc->error = IDETAPE_ERROR_GENERAL;
		tape->failed_pc = NULL;
	}
751
	drive->pc_callback(drive, 0);
Linus Torvalds's avatar
Linus Torvalds committed
752 753 754
	return ide_stopped;
}

755
static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
756 757
				   struct ide_atapi_pc *pc, struct request *rq,
				   u8 opcode)
Linus Torvalds's avatar
Linus Torvalds committed
758
{
759 760 761
	struct idetape_bh *bh = (struct idetape_bh *)rq->special;
	unsigned int length = rq->current_nr_sectors;

762
	ide_init_pc(pc);
763
	put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
Linus Torvalds's avatar
Linus Torvalds committed
764 765
	pc->c[1] = 1;
	pc->bh = bh;
766 767 768
	pc->buf = NULL;
	pc->buf_size = length * tape->blk_size;
	pc->req_xfer = pc->buf_size;
769
	if (pc->req_xfer == tape->buffer_size)
770
		pc->flags |= PC_FLAG_DMA_OK;
Linus Torvalds's avatar
Linus Torvalds committed
771

772 773 774 775 776 777 778 779 780
	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);
	}
781 782

	memcpy(rq->cmd, pc->c, 12);
Linus Torvalds's avatar
Linus Torvalds committed
783 784 785 786 787
}

static ide_startstop_t idetape_do_request(ide_drive_t *drive,
					  struct request *rq, sector_t block)
{
788
	ide_hwif_t *hwif = drive->hwif;
Linus Torvalds's avatar
Linus Torvalds committed
789
	idetape_tape_t *tape = drive->driver_data;
790
	struct ide_atapi_pc *pc = NULL;
Linus Torvalds's avatar
Linus Torvalds committed
791
	struct request *postponed_rq = tape->postponed_rq;
792
	u8 stat;
Linus Torvalds's avatar
Linus Torvalds committed
793

794 795 796 797
	debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
			" current_nr_sectors: %u\n",
			(unsigned long long)rq->sector, rq->nr_sectors,
			rq->current_nr_sectors);
Linus Torvalds's avatar
Linus Torvalds committed
798

799
	if (!blk_special_request(rq)) {
800
		/* We do not support buffer cache originated requests. */
Linus Torvalds's avatar
Linus Torvalds committed
801
		printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
802
			"request queue (%d)\n", drive->name, rq->cmd_type);
Linus Torvalds's avatar
Linus Torvalds committed
803 804 805 806
		ide_end_request(drive, 0, 0);
		return ide_stopped;
	}

807
	/* Retry a failed packet command */
808
	if (tape->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
809 810 811
		pc = tape->failed_pc;
		goto out;
	}
812

Linus Torvalds's avatar
Linus Torvalds committed
813 814 815 816 817 818 819 820 821 822 823 824 825 826
	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.
	 */
827
	stat = hwif->tp_ops->read_status(hwif);
Linus Torvalds's avatar
Linus Torvalds committed
828

829 830
	if ((drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) == 0 &&
	    (rq->cmd[13] & REQ_IDETAPE_PC2) == 0)
831
		set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
Linus Torvalds's avatar
Linus Torvalds committed
832

833
	if (drive->dev_flags & IDE_DFLAG_POST_RESET) {
834
		set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
835
		drive->dev_flags &= ~IDE_DFLAG_POST_RESET;
Linus Torvalds's avatar
Linus Torvalds committed
836 837
	}

838
	if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
839
	    (stat & ATA_DSC) == 0) {
Linus Torvalds's avatar
Linus Torvalds committed
840 841
		if (postponed_rq == NULL) {
			tape->dsc_polling_start = jiffies;
842
			tape->dsc_poll_freq = tape->best_dsc_rw_freq;
Linus Torvalds's avatar
Linus Torvalds committed
843 844 845 846
			tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
		} else if (time_after(jiffies, tape->dsc_timeout)) {
			printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
				tape->name);
847
			if (rq->cmd[13] & REQ_IDETAPE_PC2) {
Linus Torvalds's avatar
Linus Torvalds committed
848 849 850 851 852
				idetape_media_access_finished(drive);
				return ide_stopped;
			} else {
				return ide_do_reset(drive);
			}
853 854 855
		} else if (time_after(jiffies,
					tape->dsc_polling_start +
					IDETAPE_DSC_MA_THRESHOLD))
856
			tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
Linus Torvalds's avatar
Linus Torvalds committed
857 858 859
		idetape_postpone_request(drive);
		return ide_stopped;
	}
860
	if (rq->cmd[13] & REQ_IDETAPE_READ) {
861
		pc = &tape->queued_pc;
862
		ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
Linus Torvalds's avatar
Linus Torvalds committed
863 864
		goto out;
	}
865
	if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
866
		pc = &tape->queued_pc;
867
		ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
Linus Torvalds's avatar
Linus Torvalds committed
868 869
		goto out;
	}
870
	if (rq->cmd[13] & REQ_IDETAPE_PC1) {
871
		pc = (struct ide_atapi_pc *) rq->buffer;
872 873
		rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
		rq->cmd[13] |= REQ_IDETAPE_PC2;
Linus Torvalds's avatar
Linus Torvalds committed
874 875
		goto out;
	}
876
	if (rq->cmd[13] & REQ_IDETAPE_PC2) {
Linus Torvalds's avatar
Linus Torvalds committed
877 878 879 880
		idetape_media_access_finished(drive);
		return ide_stopped;
	}
	BUG();
881

882
out:
883
	return idetape_issue_pc(drive, pc);
Linus Torvalds's avatar
Linus Torvalds committed
884 885 886
}

/*
887
 * The function below uses __get_free_pages to allocate a data buffer of size
888
 * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
889
 * much as possible.
Linus Torvalds's avatar
Linus Torvalds committed
890
 *
891 892
 * It returns a pointer to the newly allocated buffer, or NULL in case of
 * failure.
Linus Torvalds's avatar
Linus Torvalds committed
893
 */
894 895
static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
						  int full, int clear)
Linus Torvalds's avatar
Linus Torvalds committed
896
{
897
	struct idetape_bh *prev_bh, *bh, *merge_bh;
898
	int pages = tape->pages_per_buffer;
899
	unsigned int order, b_allocd;
Linus Torvalds's avatar
Linus Torvalds committed
900 901
	char *b_data = NULL;

902 903
	merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
	bh = merge_bh;
Linus Torvalds's avatar
Linus Torvalds committed
904 905
	if (bh == NULL)
		goto abort;
906 907 908

	order = fls(pages) - 1;
	bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
909
	if (!bh->b_data)
Linus Torvalds's avatar
Linus Torvalds committed
910
		goto abort;
911 912 913
	b_allocd = (1 << order) * PAGE_SIZE;
	pages &= (order-1);

Linus Torvalds's avatar
Linus Torvalds committed
914
	if (clear)
915 916 917
		memset(bh->b_data, 0, b_allocd);
	bh->b_reqnext = NULL;
	bh->b_size = b_allocd;
Linus Torvalds's avatar
Linus Torvalds committed
918 919
	atomic_set(&bh->b_count, full ? bh->b_size : 0);

920 921 922
	while (pages) {
		order = fls(pages) - 1;
		b_data = (char *) __get_free_pages(GFP_KERNEL, order);
923
		if (!b_data)
Linus Torvalds's avatar
Linus Torvalds committed
924
			goto abort;
925 926
		b_allocd = (1 << order) * PAGE_SIZE;

Linus Torvalds's avatar
Linus Torvalds committed
927
		if (clear)
928 929 930 931 932 933
			memset(b_data, 0, b_allocd);

		/* newly allocated page frames below buffer header or ...*/
		if (bh->b_data == b_data + b_allocd) {
			bh->b_size += b_allocd;
			bh->b_data -= b_allocd;
Linus Torvalds's avatar
Linus Torvalds committed
934
			if (full)
935
				atomic_add(b_allocd, &bh->b_count);
Linus Torvalds's avatar
Linus Torvalds committed
936 937
			continue;
		}
938
		/* they are above the header */
Linus Torvalds's avatar
Linus Torvalds committed
939
		if (b_data == bh->b_data + bh->b_size) {