ide-tape.c 65.8 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
/* 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

/* 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
159
/*
160 161
 * 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
162 163
 */
typedef struct ide_tape_obj {
164 165 166
	ide_drive_t		*drive;
	struct ide_driver	*driver;
	struct gendisk		*disk;
167
	struct device		dev;
Linus Torvalds's avatar
Linus Torvalds committed
168

169 170
	/* used by REQ_IDETAPE_{READ,WRITE} requests */
	struct ide_atapi_pc queued_pc;
171

Linus Torvalds's avatar
Linus Torvalds committed
172
	/*
173
	 * DSC polling variables.
Linus Torvalds's avatar
Linus Torvalds committed
174
	 *
175 176 177
	 * 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
178
	 * data transfer) request in the device request queue.
Linus Torvalds's avatar
Linus Torvalds committed
179 180 181 182 183 184 185
	 */
	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 */
186 187
	unsigned long best_dsc_rw_freq;
	unsigned long dsc_poll_freq;
Linus Torvalds's avatar
Linus Torvalds committed
188 189
	unsigned long dsc_timeout;

190
	/* Read position information */
Linus Torvalds's avatar
Linus Torvalds committed
191 192
	u8 partition;
	/* Current block */
193
	unsigned int first_frame;
Linus Torvalds's avatar
Linus Torvalds committed
194

195
	/* Last error information */
Linus Torvalds's avatar
Linus Torvalds committed
196 197
	u8 sense_key, asc, ascq;

198
	/* Character device operation */
Linus Torvalds's avatar
Linus Torvalds committed
199 200 201 202
	unsigned int minor;
	/* device name */
	char name[4];
	/* Current character device data transfer direction */
203
	u8 chrdev_dir;
Linus Torvalds's avatar
Linus Torvalds committed
204

205 206
	/* tape block size, usually 512 or 1024 bytes */
	unsigned short blk_size;
Linus Torvalds's avatar
Linus Torvalds committed
207
	int user_bs_factor;
208

Linus Torvalds's avatar
Linus Torvalds committed
209
	/* Copy of the tape's Capabilities and Mechanical Page */
210
	u8 caps[20];
Linus Torvalds's avatar
Linus Torvalds committed
211 212

	/*
213
	 * Active data transfer request parameters.
Linus Torvalds's avatar
Linus Torvalds committed
214
	 *
215 216 217
	 * 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
218
	 */
219

220
	/* Data buffer size chosen based on the tape's recommendation */
221
	int buffer_size;
222 223
	/* merge buffer */
	struct idetape_bh *merge_bh;
224 225
	/* size of the merge buffer */
	int merge_bh_size;
226
	/* pointer to current buffer head within the merge buffer */
Linus Torvalds's avatar
Linus Torvalds committed
227 228 229
	struct idetape_bh *bh;
	char *b_data;
	int b_count;
230

231
	int pages_per_buffer;
Linus Torvalds's avatar
Linus Torvalds committed
232 233 234
	/* Wasted space in each stage */
	int excess_bh_size;

235
	/* Measures average tape speed */
Linus Torvalds's avatar
Linus Torvalds committed
236 237 238 239 240 241 242 243 244 245 246
	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;

247
	u32 debug_mask;
Linus Torvalds's avatar
Linus Torvalds committed
248 249
} idetape_tape_t;

250
static DEFINE_MUTEX(idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
251

252 253
static struct class *idetape_sysfs_class;

254
static void ide_tape_release(struct device *);
255

Linus Torvalds's avatar
Linus Torvalds committed
256 257 258 259
static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
{
	struct ide_tape_obj *tape = NULL;

260
	mutex_lock(&idetape_ref_mutex);
Borislav Petkov's avatar
Borislav Petkov committed
261
	tape = ide_drv_g(disk, ide_tape_obj);
262
	if (tape) {
263
		if (ide_device_get(tape->drive))
264
			tape = NULL;
265
		else
266
			get_device(&tape->dev);
267
	}
268
	mutex_unlock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
269 270 271 272 273
	return tape;
}

static void ide_tape_put(struct ide_tape_obj *tape)
{
274 275
	ide_drive_t *drive = tape->drive;

276
	mutex_lock(&idetape_ref_mutex);
277
	put_device(&tape->dev);
278
	ide_device_put(drive);
279
	mutex_unlock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
280 281 282
}

/*
283 284
 * 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
285
 */
286
static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
Linus Torvalds's avatar
Linus Torvalds committed
287 288 289 290 291

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

292
	mutex_lock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
293 294
	tape = idetape_devs[i];
	if (tape)
295
		get_device(&tape->dev);
296
	mutex_unlock(&idetape_ref_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
297 298 299
	return tape;
}

300
static int idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
301
				  unsigned int bcount)
Linus Torvalds's avatar
Linus Torvalds committed
302 303 304 305 306
{
	struct idetape_bh *bh = pc->bh;
	int count;

	while (bcount) {
307 308
		if (bh == NULL)
			break;
309 310 311
		count = min(
			(unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
			bcount);
312
		drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
313
					atomic_read(&bh->b_count), count);
Linus Torvalds's avatar
Linus Torvalds committed
314 315 316 317 318 319 320 321
		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);
		}
	}
322

Linus Torvalds's avatar
Linus Torvalds committed
323
	pc->bh = bh;
324 325

	return bcount;
Linus Torvalds's avatar
Linus Torvalds committed
326 327
}

328
static int idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
329
				   unsigned int bcount)
Linus Torvalds's avatar
Linus Torvalds committed
330 331 332 333 334
{
	struct idetape_bh *bh = pc->bh;
	int count;

	while (bcount) {
335 336
		if (bh == NULL)
			break;
Linus Torvalds's avatar
Linus Torvalds committed
337
		count = min((unsigned int)pc->b_count, (unsigned int)bcount);
338
		drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
Linus Torvalds's avatar
Linus Torvalds committed
339 340 341 342
		bcount -= count;
		pc->b_data += count;
		pc->b_count -= count;
		if (!pc->b_count) {
343 344
			bh = bh->b_reqnext;
			pc->bh = bh;
Linus Torvalds's avatar
Linus Torvalds committed
345 346 347 348 349 350
			if (bh) {
				pc->b_data = bh->b_data;
				pc->b_count = atomic_read(&bh->b_count);
			}
		}
	}
351 352

	return bcount;
Linus Torvalds's avatar
Linus Torvalds committed
353 354
}

355
static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
Linus Torvalds's avatar
Linus Torvalds committed
356 357 358
{
	struct idetape_bh *bh = pc->bh;
	int count;
359
	unsigned int bcount = pc->xferred;
Linus Torvalds's avatar
Linus Torvalds committed
360

361
	if (pc->flags & PC_FLAG_WRITING)
Linus Torvalds's avatar
Linus Torvalds committed
362 363 364
		return;
	while (bcount) {
		if (bh == NULL) {
365 366
			printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
					__func__);
Linus Torvalds's avatar
Linus Torvalds committed
367 368 369 370 371 372 373 374 375 376 377 378
			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;
}

/*
379 380
 * 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
381
 */
382
static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
Linus Torvalds's avatar
Linus Torvalds committed
383 384
{
	idetape_tape_t *tape = drive->driver_data;
385
	struct ide_atapi_pc *pc = drive->failed_pc;
Linus Torvalds's avatar
Linus Torvalds committed
386

387 388 389
	tape->sense_key = sense[2] & 0xF;
	tape->asc       = sense[12];
	tape->ascq      = sense[13];
390 391 392

	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
393

394
	/* Correct pc->xferred by asking the tape.	 */
395
	if (pc->flags & PC_FLAG_DMA_ERROR) {
396
		pc->xferred = pc->req_xfer -
397
			tape->blk_size *
398
			get_unaligned_be32(&sense[3]);
399
		idetape_update_buffers(drive, pc);
Linus Torvalds's avatar
Linus Torvalds committed
400 401 402 403 404 405 406
	}

	/*
	 * 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.
	 */
407
	if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
408 409 410
	    /* 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
411 412 413
			/* don't report an error, everything's ok */
			pc->error = 0;
			/* don't retry read/write */
414
			pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
415 416
		}
	}
417
	if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
418
		pc->error = IDE_DRV_ERROR_FILEMARK;
419
		pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
420
	}
421
	if (pc->c[0] == WRITE_6) {
422 423
		if ((sense[2] & 0x40) || (tape->sense_key == 0xd
		     && tape->asc == 0x0 && tape->ascq == 0x2)) {
424
			pc->error = IDE_DRV_ERROR_EOD;
425
			pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
426 427
		}
	}
428
	if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
429
		if (tape->sense_key == 8) {
430
			pc->error = IDE_DRV_ERROR_EOD;
431
			pc->flags |= PC_FLAG_ABORT;
Linus Torvalds's avatar
Linus Torvalds committed
432
		}
433
		if (!(pc->flags & PC_FLAG_ABORT) &&
434
		    pc->xferred)
Linus Torvalds's avatar
Linus Torvalds committed
435 436 437 438
			pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
	}
}

439
/* Free data buffers completely. */
440
static void ide_tape_kfree_buffer(idetape_tape_t *tape)
Linus Torvalds's avatar
Linus Torvalds committed
441
{
442
	struct idetape_bh *prev_bh, *bh = tape->merge_bh;
443 444 445 446 447 448 449 450 451 452 453 454

	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
455 456 457 458 459 460 461
		}
		prev_bh = bh;
		bh = bh->b_reqnext;
		kfree(prev_bh);
	}
}

462 463
static void ide_tape_handle_dsc(ide_drive_t *);

464
static int ide_tape_callback(ide_drive_t *drive, int dsc)
Linus Torvalds's avatar
Linus Torvalds committed
465 466
{
	idetape_tape_t *tape = drive->driver_data;
467
	struct ide_atapi_pc *pc = drive->pc;
468
	struct request *rq = drive->hwif->rq;
469
	int uptodate = pc->error ? 0 : 1;
470
	int err = uptodate ? 0 : IDE_DRV_ERROR_GENERAL;
Linus Torvalds's avatar
Linus Torvalds committed
471

472 473
	debug_log(DBG_PROCS, "Enter %s\n", __func__);

474 475 476
	if (dsc)
		ide_tape_handle_dsc(drive);

477 478
	if (drive->failed_pc == pc)
		drive->failed_pc = NULL;
479

480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500
	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) {
		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;

501 502 503 504
		if (pc->error) {
			uptodate = 0;
			err = pc->error;
		}
505
	} else if (pc->c[0] == READ_POSITION && uptodate) {
506
		u8 *readpos = pc->buf;
507 508 509 510 511 512 513 514 515

		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");
516
			clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
517
			uptodate = 0;
518
			err = IDE_DRV_ERROR_GENERAL;
519 520
		} else {
			debug_log(DBG_SENSE, "Block Location - %u\n",
521
					be32_to_cpup((__be32 *)&readpos[4]));
522 523

			tape->partition = readpos[1];
524
			tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
525
			set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
526
		}
Linus Torvalds's avatar
Linus Torvalds committed
527
	}
528

529 530
	rq->errors = err;

531
	return uptodate;
Linus Torvalds's avatar
Linus Torvalds committed
532 533 534
}

/*
535
 * Postpone the current request so that ide.c will be able to service requests
536
 * from another device on the same port while we are polling for DSC.
Linus Torvalds's avatar
Linus Torvalds committed
537
 */
538
static void idetape_postpone_request(ide_drive_t *drive)
Linus Torvalds's avatar
Linus Torvalds committed
539 540 541
{
	idetape_tape_t *tape = drive->driver_data;

542 543
	debug_log(DBG_PROCS, "Enter %s\n", __func__);

544 545
	tape->postponed_rq = drive->hwif->rq;

546
	ide_stall_queue(drive, tape->dsc_poll_freq);
Linus Torvalds's avatar
Linus Torvalds committed
547 548
}

549 550 551 552 553 554 555 556 557 558 559 560
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);
}

561
static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
562 563
				unsigned int bcount, int write)
{
564 565
	unsigned int bleft;

566
	if (write)
567
		bleft = idetape_output_buffers(drive, pc, bcount);
568
	else
569
		bleft = idetape_input_buffers(drive, pc, bcount);
570

571
	return bcount - bleft;
572
}
573

Linus Torvalds's avatar
Linus Torvalds committed
574
/*
575
 * Packet Command Interface
Linus Torvalds's avatar
Linus Torvalds committed
576
 *
577
 * The current Packet Command is available in drive->pc, and will not change
578 579
 * 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
580
 *
581
 * The handling will be done in three stages:
Linus Torvalds's avatar
Linus Torvalds committed
582
 *
583
 * 1. ide_tape_issue_pc will send the packet command to the drive, and will set
584
 * the interrupt handler to ide_pc_intr.
Linus Torvalds's avatar
Linus Torvalds committed
585
 *
586
 * 2. On each interrupt, ide_pc_intr will be called. This step will be
587
 * repeated until the device signals us that no more interrupts will be issued.
Linus Torvalds's avatar
Linus Torvalds committed
588
 *
589 590 591 592 593 594 595
 * 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
596
 *
597 598
 * 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
599
 *
600
 * 4. When the packet command is finished, it will be checked for errors.
Linus Torvalds's avatar
Linus Torvalds committed
601
 *
602 603 604
 * 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
605
 *
606 607 608
 * 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
609 610
 */

611 612 613
static ide_startstop_t ide_tape_issue_pc(ide_drive_t *drive,
					 struct ide_cmd *cmd,
					 struct ide_atapi_pc *pc)
Linus Torvalds's avatar
Linus Torvalds committed
614 615 616
{
	idetape_tape_t *tape = drive->driver_data;

617 618
	if (drive->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
		drive->failed_pc = pc;
619

Linus Torvalds's avatar
Linus Torvalds committed
620
	/* Set the current packet command */
621
	drive->pc = pc;
Linus Torvalds's avatar
Linus Torvalds committed
622 623

	if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
624
		(pc->flags & PC_FLAG_ABORT)) {
Linus Torvalds's avatar
Linus Torvalds committed
625
		/*
626 627 628
		 * 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
629
		 */
630
		if (!(pc->flags & PC_FLAG_ABORT)) {
631
			if (!(pc->c[0] == TEST_UNIT_READY &&
Linus Torvalds's avatar
Linus Torvalds committed
632 633 634 635 636 637 638 639 640 641
			      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 */
642
			pc->error = IDE_DRV_ERROR_GENERAL;
Linus Torvalds's avatar
Linus Torvalds committed
643
		}
644
		drive->failed_pc = NULL;
645
		drive->pc_callback(drive, 0);
646
		return ide_stopped;
Linus Torvalds's avatar
Linus Torvalds committed
647
	}
648
	debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
Linus Torvalds's avatar
Linus Torvalds committed
649 650 651

	pc->retries++;

652
	return ide_issue_pc(drive, cmd);
Linus Torvalds's avatar
Linus Torvalds committed
653 654
}

655
/* A mode sense command is used to "sense" tape parameters. */
656
static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
Linus Torvalds's avatar
Linus Torvalds committed
657
{
658
	ide_init_pc(pc);
659
	pc->c[0] = MODE_SENSE;
Linus Torvalds's avatar
Linus Torvalds committed
660
	if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
661 662
		/* DBD = 1 - Don't return block descriptors */
		pc->c[1] = 8;
Linus Torvalds's avatar
Linus Torvalds committed
663 664 665 666 667 668 669 670 671
	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;
672 673
	/* We will just discard data in that case */
	pc->c[4] = 255;
Linus Torvalds's avatar
Linus Torvalds committed
674
	if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
675
		pc->req_xfer = 12;
Linus Torvalds's avatar
Linus Torvalds committed
676
	else if (page_code == IDETAPE_CAPABILITIES_PAGE)
677
		pc->req_xfer = 24;
Linus Torvalds's avatar
Linus Torvalds committed
678
	else
679
		pc->req_xfer = 50;
Linus Torvalds's avatar
Linus Torvalds committed
680 681
}

682
static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
Linus Torvalds's avatar
Linus Torvalds committed
683
{
684
	ide_hwif_t *hwif = drive->hwif;
Linus Torvalds's avatar
Linus Torvalds committed
685
	idetape_tape_t *tape = drive->driver_data;
686
	struct ide_atapi_pc *pc = drive->pc;
687
	u8 stat;
Linus Torvalds's avatar
Linus Torvalds committed
688

689
	stat = hwif->tp_ops->read_status(hwif);
690

691 692
	if (stat & ATA_DSC) {
		if (stat & ATA_ERR) {
Linus Torvalds's avatar
Linus Torvalds committed
693
			/* Error detected */
694
			if (pc->c[0] != TEST_UNIT_READY)
Linus Torvalds's avatar
Linus Torvalds committed
695 696 697
				printk(KERN_ERR "ide-tape: %s: I/O error, ",
						tape->name);
			/* Retry operation */
698
			ide_retry_pc(drive, tape->disk);
699
			return ide_stopped;
Linus Torvalds's avatar
Linus Torvalds committed
700 701 702
		}
		pc->error = 0;
	} else {
703
		pc->error = IDE_DRV_ERROR_GENERAL;
704
		drive->failed_pc = NULL;
Linus Torvalds's avatar
Linus Torvalds committed
705
	}
706
	drive->pc_callback(drive, 0);
Linus Torvalds's avatar
Linus Torvalds committed
707 708 709
	return ide_stopped;
}

710
static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
711 712
				   struct ide_atapi_pc *pc, struct request *rq,
				   u8 opcode)
Linus Torvalds's avatar
Linus Torvalds committed
713
{
714 715 716
	struct idetape_bh *bh = (struct idetape_bh *)rq->special;
	unsigned int length = rq->current_nr_sectors;

717
	ide_init_pc(pc);
718
	put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
Linus Torvalds's avatar
Linus Torvalds committed
719 720
	pc->c[1] = 1;
	pc->bh = bh;
721 722 723
	pc->buf = NULL;
	pc->buf_size = length * tape->blk_size;
	pc->req_xfer = pc->buf_size;
724
	if (pc->req_xfer == tape->buffer_size)
725
		pc->flags |= PC_FLAG_DMA_OK;
Linus Torvalds's avatar
Linus Torvalds committed
726

727 728 729 730 731 732 733 734 735
	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);
	}
736 737

	memcpy(rq->cmd, pc->c, 12);
Linus Torvalds's avatar
Linus Torvalds committed
738 739 740 741 742
}

static ide_startstop_t idetape_do_request(ide_drive_t *drive,
					  struct request *rq, sector_t block)
{
743
	ide_hwif_t *hwif = drive->hwif;
Linus Torvalds's avatar
Linus Torvalds committed
744
	idetape_tape_t *tape = drive->driver_data;
745
	struct ide_atapi_pc *pc = NULL;
Linus Torvalds's avatar
Linus Torvalds committed
746
	struct request *postponed_rq = tape->postponed_rq;
747
	struct ide_cmd cmd;
748
	u8 stat;
Linus Torvalds's avatar
Linus Torvalds committed
749

750 751 752 753
	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
754

755
	if (!blk_special_request(rq)) {
756
		/* We do not support buffer cache originated requests. */
Linus Torvalds's avatar
Linus Torvalds committed
757
		printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
758
			"request queue (%d)\n", drive->name, rq->cmd_type);
759 760
		if (blk_fs_request(rq) == 0 && rq->errors == 0)
			rq->errors = -EIO;
761
		ide_complete_rq(drive, -EIO, ide_rq_bytes(rq));
Linus Torvalds's avatar
Linus Torvalds committed
762 763 764
		return ide_stopped;
	}

765
	/* Retry a failed packet command */
766 767
	if (drive->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
		pc = drive->failed_pc;
768 769
		goto out;
	}
770

Linus Torvalds's avatar
Linus Torvalds committed
771 772 773 774
	if (postponed_rq != NULL)
		if (rq != postponed_rq) {
			printk(KERN_ERR "ide-tape: ide-tape.c bug - "
					"Two DSC requests were queued\n");
775
			drive->failed_pc = NULL;
776
			rq->errors = 0;
777
			ide_complete_rq(drive, 0, blk_rq_bytes(rq));
Linus Torvalds's avatar
Linus Torvalds committed
778 779 780 781 782 783 784 785 786
			return ide_stopped;
		}

	tape->postponed_rq = NULL;

	/*
	 * If the tape is still busy, postpone our request and service
	 * the other device meanwhile.
	 */
787
	stat = hwif->tp_ops->read_status(hwif);
Linus Torvalds's avatar
Linus Torvalds committed
788

789 790
	if ((drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) == 0 &&
	    (rq->cmd[13] & REQ_IDETAPE_PC2) == 0)
791
		set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
Linus Torvalds's avatar
Linus Torvalds committed
792

793
	if (drive->dev_flags & IDE_DFLAG_POST_RESET) {
794
		set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
795
		drive->dev_flags &= ~IDE_DFLAG_POST_RESET;
Linus Torvalds's avatar
Linus Torvalds committed
796 797
	}

798
	if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
799
	    (stat & ATA_DSC) == 0) {
Linus Torvalds's avatar
Linus Torvalds committed
800 801
		if (postponed_rq == NULL) {
			tape->dsc_polling_start = jiffies;
802
			tape->dsc_poll_freq = tape->best_dsc_rw_freq;
Linus Torvalds's avatar
Linus Torvalds committed
803 804 805 806
			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);
807
			if (rq->cmd[13] & REQ_IDETAPE_PC2) {
Linus Torvalds's avatar
Linus Torvalds committed
808 809 810 811 812
				idetape_media_access_finished(drive);
				return ide_stopped;
			} else {
				return ide_do_reset(drive);
			}
813 814 815
		} else if (time_after(jiffies,
					tape->dsc_polling_start +
					IDETAPE_DSC_MA_THRESHOLD))
816
			tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
Linus Torvalds's avatar
Linus Torvalds committed
817 818 819
		idetape_postpone_request(drive);
		return ide_stopped;
	}
820
	if (rq->cmd[13] & REQ_IDETAPE_READ) {
821
		pc = &tape->queued_pc;
822
		ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
Linus Torvalds's avatar
Linus Torvalds committed
823 824
		goto out;
	}
825
	if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
826
		pc = &tape->queued_pc;
827
		ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
Linus Torvalds's avatar
Linus Torvalds committed
828 829
		goto out;
	}
830
	if (rq->cmd[13] & REQ_IDETAPE_PC1) {
Tejun Heo's avatar
Tejun Heo committed
831
		pc = (struct ide_atapi_pc *)rq->special;
832 833
		rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
		rq->cmd[13] |= REQ_IDETAPE_PC2;
Linus Torvalds's avatar
Linus Torvalds committed
834 835
		goto out;
	}
836
	if (rq->cmd[13] & REQ_IDETAPE_PC2) {
Linus Torvalds's avatar
Linus Torvalds committed
837 838 839 840
		idetape_media_access_finished(drive);
		return ide_stopped;
	}
	BUG();
841

842
out:
843 844 845 846 847 848 849 850
	memset(&cmd, 0, sizeof(cmd));

	if (rq_data_dir(rq))
		cmd.tf_flags |= IDE_TFLAG_WRITE;

	cmd.rq = rq;

	return ide_tape_issue_pc(drive, &cmd, pc);
Linus Torvalds's avatar
Linus Torvalds committed
851 852 853
}

/*
854
 * The function below uses __get_free_pages to allocate a data buffer of size
855
 * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
856
 * much as possible.
Linus Torvalds's avatar
Linus Torvalds committed
857
 *
858 859
 * It returns a pointer to the newly allocated buffer, or NULL in case of
 * failure.
Linus Torvalds's avatar
Linus Torvalds committed
860
 */
861 862
static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
						  int full, int clear)
Linus Torvalds's avatar
Linus Torvalds committed
863
{
864
	struct idetape_bh *prev_bh, *bh, *merge_bh;
865
	int pages = tape->pages_per_buffer;
866
	unsigned int order, b_allocd;
Linus Torvalds's avatar
Linus Torvalds committed
867 868
	char *b_data = NULL;

869 870
	merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
	bh = merge_bh;
Linus Torvalds's avatar
Linus Torvalds committed
871 872
	if (bh == NULL)
		goto abort;
873 874 875

	order = fls(pages) - 1;
	bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
876
	if (!bh->b_data)
Linus Torvalds's avatar
Linus Torvalds committed
877
		goto abort;
878 879 880
	b_allocd = (1 << order) * PAGE_SIZE;
	pages &= (order-1);

Linus Torvalds's avatar
Linus Torvalds committed
881
	if (clear)
882 883 884
		memset(bh->b_data, 0, b_allocd);
	bh->b_reqnext = NULL;
	bh->b_size =