xref: /openbmc/linux/drivers/scsi/sr.c (revision 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2)
1 /*
2  *  sr.c Copyright (C) 1992 David Giller
3  *           Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
4  *
5  *  adapted from:
6  *      sd.c Copyright (C) 1992 Drew Eckhardt
7  *      Linux scsi disk driver by
8  *              Drew Eckhardt <drew@colorado.edu>
9  *
10  *	Modified by Eric Youngdale ericy@andante.org to
11  *	add scatter-gather, multiple outstanding request, and other
12  *	enhancements.
13  *
14  *      Modified by Eric Youngdale eric@andante.org to support loadable
15  *      low-level scsi drivers.
16  *
17  *      Modified by Thomas Quinot thomas@melchior.cuivre.fdn.fr to
18  *      provide auto-eject.
19  *
20  *      Modified by Gerd Knorr <kraxel@cs.tu-berlin.de> to support the
21  *      generic cdrom interface
22  *
23  *      Modified by Jens Axboe <axboe@suse.de> - Uniform sr_packet()
24  *      interface, capabilities probe additions, ioctl cleanups, etc.
25  *
26  *	Modified by Richard Gooch <rgooch@atnf.csiro.au> to support devfs
27  *
28  *	Modified by Jens Axboe <axboe@suse.de> - support DVD-RAM
29  *	transparently and lose the GHOST hack
30  *
31  *	Modified by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
32  *	check resource allocation in sr_init and some cleanups
33  */
34 
35 #include <linux/module.h>
36 #include <linux/fs.h>
37 #include <linux/kernel.h>
38 #include <linux/sched.h>
39 #include <linux/mm.h>
40 #include <linux/bio.h>
41 #include <linux/string.h>
42 #include <linux/errno.h>
43 #include <linux/cdrom.h>
44 #include <linux/interrupt.h>
45 #include <linux/init.h>
46 #include <linux/blkdev.h>
47 #include <asm/uaccess.h>
48 
49 #include <scsi/scsi.h>
50 #include <scsi/scsi_dbg.h>
51 #include <scsi/scsi_device.h>
52 #include <scsi/scsi_driver.h>
53 #include <scsi/scsi_eh.h>
54 #include <scsi/scsi_host.h>
55 #include <scsi/scsi_ioctl.h>	/* For the door lock/unlock commands */
56 #include <scsi/scsi_request.h>
57 
58 #include "scsi_logging.h"
59 #include "sr.h"
60 
61 
62 #define SR_DISKS	256
63 
64 #define MAX_RETRIES	3
65 #define SR_TIMEOUT	(30 * HZ)
66 #define SR_CAPABILITIES \
67 	(CDC_CLOSE_TRAY|CDC_OPEN_TRAY|CDC_LOCK|CDC_SELECT_SPEED| \
68 	 CDC_SELECT_DISC|CDC_MULTI_SESSION|CDC_MCN|CDC_MEDIA_CHANGED| \
69 	 CDC_PLAY_AUDIO|CDC_RESET|CDC_IOCTLS|CDC_DRIVE_STATUS| \
70 	 CDC_CD_R|CDC_CD_RW|CDC_DVD|CDC_DVD_R|CDC_DVD_RAM|CDC_GENERIC_PACKET| \
71 	 CDC_MRW|CDC_MRW_W|CDC_RAM)
72 
73 static int sr_probe(struct device *);
74 static int sr_remove(struct device *);
75 static int sr_init_command(struct scsi_cmnd *);
76 
77 static struct scsi_driver sr_template = {
78 	.owner			= THIS_MODULE,
79 	.gendrv = {
80 		.name   	= "sr",
81 		.probe		= sr_probe,
82 		.remove		= sr_remove,
83 	},
84 	.init_command		= sr_init_command,
85 };
86 
87 static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
88 static DEFINE_SPINLOCK(sr_index_lock);
89 
90 /* This semaphore is used to mediate the 0->1 reference get in the
91  * face of object destruction (i.e. we can't allow a get on an
92  * object after last put) */
93 static DECLARE_MUTEX(sr_ref_sem);
94 
95 static int sr_open(struct cdrom_device_info *, int);
96 static void sr_release(struct cdrom_device_info *);
97 
98 static void get_sectorsize(struct scsi_cd *);
99 static void get_capabilities(struct scsi_cd *);
100 
101 static int sr_media_change(struct cdrom_device_info *, int);
102 static int sr_packet(struct cdrom_device_info *, struct packet_command *);
103 
104 static struct cdrom_device_ops sr_dops = {
105 	.open			= sr_open,
106 	.release	 	= sr_release,
107 	.drive_status	 	= sr_drive_status,
108 	.media_changed		= sr_media_change,
109 	.tray_move		= sr_tray_move,
110 	.lock_door		= sr_lock_door,
111 	.select_speed		= sr_select_speed,
112 	.get_last_session	= sr_get_last_session,
113 	.get_mcn		= sr_get_mcn,
114 	.reset			= sr_reset,
115 	.audio_ioctl		= sr_audio_ioctl,
116 	.dev_ioctl		= sr_dev_ioctl,
117 	.capability		= SR_CAPABILITIES,
118 	.generic_packet		= sr_packet,
119 };
120 
121 static void sr_kref_release(struct kref *kref);
122 
123 static inline struct scsi_cd *scsi_cd(struct gendisk *disk)
124 {
125 	return container_of(disk->private_data, struct scsi_cd, driver);
126 }
127 
128 /*
129  * The get and put routines for the struct scsi_cd.  Note this entity
130  * has a scsi_device pointer and owns a reference to this.
131  */
132 static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk)
133 {
134 	struct scsi_cd *cd = NULL;
135 
136 	down(&sr_ref_sem);
137 	if (disk->private_data == NULL)
138 		goto out;
139 	cd = scsi_cd(disk);
140 	kref_get(&cd->kref);
141 	if (scsi_device_get(cd->device))
142 		goto out_put;
143 	goto out;
144 
145  out_put:
146 	kref_put(&cd->kref, sr_kref_release);
147 	cd = NULL;
148  out:
149 	up(&sr_ref_sem);
150 	return cd;
151 }
152 
153 static inline void scsi_cd_put(struct scsi_cd *cd)
154 {
155 	struct scsi_device *sdev = cd->device;
156 
157 	down(&sr_ref_sem);
158 	kref_put(&cd->kref, sr_kref_release);
159 	scsi_device_put(sdev);
160 	up(&sr_ref_sem);
161 }
162 
163 /*
164  * This function checks to see if the media has been changed in the
165  * CDROM drive.  It is possible that we have already sensed a change,
166  * or the drive may have sensed one and not yet reported it.  We must
167  * be ready for either case. This function always reports the current
168  * value of the changed bit.  If flag is 0, then the changed bit is reset.
169  * This function could be done as an ioctl, but we would need to have
170  * an inode for that to work, and we do not always have one.
171  */
172 
173 int sr_media_change(struct cdrom_device_info *cdi, int slot)
174 {
175 	struct scsi_cd *cd = cdi->handle;
176 	int retval;
177 
178 	if (CDSL_CURRENT != slot) {
179 		/* no changer support */
180 		return -EINVAL;
181 	}
182 
183 	retval = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES);
184 	if (retval) {
185 		/* Unable to test, unit probably not ready.  This usually
186 		 * means there is no disc in the drive.  Mark as changed,
187 		 * and we will figure it out later once the drive is
188 		 * available again.  */
189 		cd->device->changed = 1;
190 		return 1;	/* This will force a flush, if called from
191 				 * check_disk_change */
192 	};
193 
194 	retval = cd->device->changed;
195 	cd->device->changed = 0;
196 	/* If the disk changed, the capacity will now be different,
197 	 * so we force a re-read of this information */
198 	if (retval) {
199 		/* check multisession offset etc */
200 		sr_cd_check(cdi);
201 
202 		/*
203 		 * If the disk changed, the capacity will now be different,
204 		 * so we force a re-read of this information
205 		 * Force 2048 for the sector size so that filesystems won't
206 		 * be trying to use something that is too small if the disc
207 		 * has changed.
208 		 */
209 		cd->needs_sector_size = 1;
210 		cd->device->sector_size = 2048;
211 	}
212 	return retval;
213 }
214 
215 /*
216  * rw_intr is the interrupt routine for the device driver.
217  *
218  * It will be notified on the end of a SCSI read / write, and will take on
219  * of several actions based on success or failure.
220  */
221 static void rw_intr(struct scsi_cmnd * SCpnt)
222 {
223 	int result = SCpnt->result;
224 	int this_count = SCpnt->bufflen;
225 	int good_bytes = (result == 0 ? this_count : 0);
226 	int block_sectors = 0;
227 	long error_sector;
228 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
229 
230 #ifdef DEBUG
231 	printk("sr.c done: %x\n", result);
232 #endif
233 
234 	/*
235 	 * Handle MEDIUM ERRORs or VOLUME OVERFLOWs that indicate partial
236 	 * success.  Since this is a relatively rare error condition, no
237 	 * care is taken to avoid unnecessary additional work such as
238 	 * memcpy's that could be avoided.
239 	 */
240 	if (driver_byte(result) != 0 &&		/* An error occurred */
241 	    (SCpnt->sense_buffer[0] & 0x7f) == 0x70) { /* Sense current */
242 		switch (SCpnt->sense_buffer[2]) {
243 		case MEDIUM_ERROR:
244 		case VOLUME_OVERFLOW:
245 		case ILLEGAL_REQUEST:
246 			if (!(SCpnt->sense_buffer[0] & 0x90))
247 				break;
248 			if (!blk_fs_request(SCpnt->request))
249 				break;
250 			error_sector = (SCpnt->sense_buffer[3] << 24) |
251 				(SCpnt->sense_buffer[4] << 16) |
252 				(SCpnt->sense_buffer[5] << 8) |
253 				SCpnt->sense_buffer[6];
254 			if (SCpnt->request->bio != NULL)
255 				block_sectors =
256 					bio_sectors(SCpnt->request->bio);
257 			if (block_sectors < 4)
258 				block_sectors = 4;
259 			if (cd->device->sector_size == 2048)
260 				error_sector <<= 2;
261 			error_sector &= ~(block_sectors - 1);
262 			good_bytes = (error_sector - SCpnt->request->sector) << 9;
263 			if (good_bytes < 0 || good_bytes >= this_count)
264 				good_bytes = 0;
265 			/*
266 			 * The SCSI specification allows for the value
267 			 * returned by READ CAPACITY to be up to 75 2K
268 			 * sectors past the last readable block.
269 			 * Therefore, if we hit a medium error within the
270 			 * last 75 2K sectors, we decrease the saved size
271 			 * value.
272 			 */
273 			if (error_sector < get_capacity(cd->disk) &&
274 			    cd->capacity - error_sector < 4 * 75)
275 				set_capacity(cd->disk, error_sector);
276 			break;
277 
278 		case RECOVERED_ERROR:
279 
280 			/*
281 			 * An error occured, but it recovered.  Inform the
282 			 * user, but make sure that it's not treated as a
283 			 * hard error.
284 			 */
285 			scsi_print_sense("sr", SCpnt);
286 			SCpnt->result = 0;
287 			SCpnt->sense_buffer[0] = 0x0;
288 			good_bytes = this_count;
289 			break;
290 
291 		default:
292 			break;
293 		}
294 	}
295 
296 	/*
297 	 * This calls the generic completion function, now that we know
298 	 * how many actual sectors finished, and how many sectors we need
299 	 * to say have failed.
300 	 */
301 	scsi_io_completion(SCpnt, good_bytes, block_sectors << 9);
302 }
303 
304 static int sr_init_command(struct scsi_cmnd * SCpnt)
305 {
306 	int block=0, this_count, s_size, timeout = SR_TIMEOUT;
307 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
308 
309 	SCSI_LOG_HLQUEUE(1, printk("Doing sr request, dev = %s, block = %d\n",
310 				cd->disk->disk_name, block));
311 
312 	if (!cd->device || !scsi_device_online(cd->device)) {
313 		SCSI_LOG_HLQUEUE(2, printk("Finishing %ld sectors\n",
314 					SCpnt->request->nr_sectors));
315 		SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
316 		return 0;
317 	}
318 
319 	if (cd->device->changed) {
320 		/*
321 		 * quietly refuse to do anything to a changed disc until the
322 		 * changed bit has been reset
323 		 */
324 		return 0;
325 	}
326 
327 	/*
328 	 * these are already setup, just copy cdb basically
329 	 */
330 	if (SCpnt->request->flags & REQ_BLOCK_PC) {
331 		struct request *rq = SCpnt->request;
332 
333 		if (sizeof(rq->cmd) > sizeof(SCpnt->cmnd))
334 			return 0;
335 
336 		memcpy(SCpnt->cmnd, rq->cmd, sizeof(SCpnt->cmnd));
337 		if (!rq->data_len)
338 			SCpnt->sc_data_direction = DMA_NONE;
339 		else if (rq_data_dir(rq) == WRITE)
340 			SCpnt->sc_data_direction = DMA_TO_DEVICE;
341 		else
342 			SCpnt->sc_data_direction = DMA_FROM_DEVICE;
343 
344 		this_count = rq->data_len;
345 		if (rq->timeout)
346 			timeout = rq->timeout;
347 
348 		SCpnt->transfersize = rq->data_len;
349 		goto queue;
350 	}
351 
352 	if (!(SCpnt->request->flags & REQ_CMD)) {
353 		blk_dump_rq_flags(SCpnt->request, "sr unsup command");
354 		return 0;
355 	}
356 
357 	/*
358 	 * we do lazy blocksize switching (when reading XA sectors,
359 	 * see CDROMREADMODE2 ioctl)
360 	 */
361 	s_size = cd->device->sector_size;
362 	if (s_size > 2048) {
363 		if (!in_interrupt())
364 			sr_set_blocklength(cd, 2048);
365 		else
366 			printk("sr: can't switch blocksize: in interrupt\n");
367 	}
368 
369 	if (s_size != 512 && s_size != 1024 && s_size != 2048) {
370 		printk("sr: bad sector size %d\n", s_size);
371 		return 0;
372 	}
373 
374 	if (rq_data_dir(SCpnt->request) == WRITE) {
375 		if (!cd->device->writeable)
376 			return 0;
377 		SCpnt->cmnd[0] = WRITE_10;
378 		SCpnt->sc_data_direction = DMA_TO_DEVICE;
379  	 	cd->cdi.media_written = 1;
380 	} else if (rq_data_dir(SCpnt->request) == READ) {
381 		SCpnt->cmnd[0] = READ_10;
382 		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
383 	} else {
384 		blk_dump_rq_flags(SCpnt->request, "Unknown sr command");
385 		return 0;
386 	}
387 
388 	{
389 		struct scatterlist *sg = SCpnt->request_buffer;
390 		int i, size = 0;
391 		for (i = 0; i < SCpnt->use_sg; i++)
392 			size += sg[i].length;
393 
394 		if (size != SCpnt->request_bufflen && SCpnt->use_sg) {
395 			printk(KERN_ERR "sr: mismatch count %d, bytes %d\n",
396 					size, SCpnt->request_bufflen);
397 			if (SCpnt->request_bufflen > size)
398 				SCpnt->request_bufflen = SCpnt->bufflen = size;
399 		}
400 	}
401 
402 	/*
403 	 * request doesn't start on hw block boundary, add scatter pads
404 	 */
405 	if (((unsigned int)SCpnt->request->sector % (s_size >> 9)) ||
406 	    (SCpnt->request_bufflen % s_size)) {
407 		printk("sr: unaligned transfer\n");
408 		return 0;
409 	}
410 
411 	this_count = (SCpnt->request_bufflen >> 9) / (s_size >> 9);
412 
413 
414 	SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n",
415 				cd->cdi.name,
416 				(rq_data_dir(SCpnt->request) == WRITE) ?
417 					"writing" : "reading",
418 				this_count, SCpnt->request->nr_sectors));
419 
420 	SCpnt->cmnd[1] = 0;
421 	block = (unsigned int)SCpnt->request->sector / (s_size >> 9);
422 
423 	if (this_count > 0xffff) {
424 		this_count = 0xffff;
425 		SCpnt->request_bufflen = SCpnt->bufflen =
426 				this_count * s_size;
427 	}
428 
429 	SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
430 	SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
431 	SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
432 	SCpnt->cmnd[5] = (unsigned char) block & 0xff;
433 	SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
434 	SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
435 	SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
436 
437 	/*
438 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
439 	 * host adapter, it's safe to assume that we can at least transfer
440 	 * this many bytes between each connect / disconnect.
441 	 */
442 	SCpnt->transfersize = cd->device->sector_size;
443 	SCpnt->underflow = this_count << 9;
444 
445 queue:
446 	SCpnt->allowed = MAX_RETRIES;
447 	SCpnt->timeout_per_command = timeout;
448 
449 	/*
450 	 * This is the completion routine we use.  This is matched in terms
451 	 * of capability to this function.
452 	 */
453 	SCpnt->done = rw_intr;
454 
455 	/*
456 	 * This indicates that the command is ready from our end to be
457 	 * queued.
458 	 */
459 	return 1;
460 }
461 
462 static int sr_block_open(struct inode *inode, struct file *file)
463 {
464 	struct gendisk *disk = inode->i_bdev->bd_disk;
465 	struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
466 	int ret = 0;
467 
468 	if(!(cd = scsi_cd_get(disk)))
469 		return -ENXIO;
470 
471 	if((ret = cdrom_open(&cd->cdi, inode, file)) != 0)
472 		scsi_cd_put(cd);
473 
474 	return ret;
475 }
476 
477 static int sr_block_release(struct inode *inode, struct file *file)
478 {
479 	int ret;
480 	struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
481 	ret = cdrom_release(&cd->cdi, file);
482 	if(ret)
483 		return ret;
484 
485 	scsi_cd_put(cd);
486 
487 	return 0;
488 }
489 
490 static int sr_block_ioctl(struct inode *inode, struct file *file, unsigned cmd,
491 			  unsigned long arg)
492 {
493 	struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
494 	struct scsi_device *sdev = cd->device;
495 
496         /*
497          * Send SCSI addressing ioctls directly to mid level, send other
498          * ioctls to cdrom/block level.
499          */
500         switch (cmd) {
501                 case SCSI_IOCTL_GET_IDLUN:
502                 case SCSI_IOCTL_GET_BUS_NUMBER:
503                         return scsi_ioctl(sdev, cmd, (void __user *)arg);
504 	}
505 	return cdrom_ioctl(file, &cd->cdi, inode, cmd, arg);
506 }
507 
508 static int sr_block_media_changed(struct gendisk *disk)
509 {
510 	struct scsi_cd *cd = scsi_cd(disk);
511 	return cdrom_media_changed(&cd->cdi);
512 }
513 
514 static struct block_device_operations sr_bdops =
515 {
516 	.owner		= THIS_MODULE,
517 	.open		= sr_block_open,
518 	.release	= sr_block_release,
519 	.ioctl		= sr_block_ioctl,
520 	.media_changed	= sr_block_media_changed,
521 	/*
522 	 * No compat_ioctl for now because sr_block_ioctl never
523 	 * seems to pass arbitary ioctls down to host drivers.
524 	 */
525 };
526 
527 static int sr_open(struct cdrom_device_info *cdi, int purpose)
528 {
529 	struct scsi_cd *cd = cdi->handle;
530 	struct scsi_device *sdev = cd->device;
531 	int retval;
532 
533 	/*
534 	 * If the device is in error recovery, wait until it is done.
535 	 * If the device is offline, then disallow any access to it.
536 	 */
537 	retval = -ENXIO;
538 	if (!scsi_block_when_processing_errors(sdev))
539 		goto error_out;
540 
541 	/*
542 	 * If this device did not have media in the drive at boot time, then
543 	 * we would have been unable to get the sector size.  Check to see if
544 	 * this is the case, and try again.
545 	 */
546 	if (cd->needs_sector_size)
547 		get_sectorsize(cd);
548 	return 0;
549 
550 error_out:
551 	return retval;
552 }
553 
554 static void sr_release(struct cdrom_device_info *cdi)
555 {
556 	struct scsi_cd *cd = cdi->handle;
557 
558 	if (cd->device->sector_size > 2048)
559 		sr_set_blocklength(cd, 2048);
560 
561 }
562 
563 static int sr_probe(struct device *dev)
564 {
565 	struct scsi_device *sdev = to_scsi_device(dev);
566 	struct gendisk *disk;
567 	struct scsi_cd *cd;
568 	int minor, error;
569 
570 	error = -ENODEV;
571 	if (sdev->type != TYPE_ROM && sdev->type != TYPE_WORM)
572 		goto fail;
573 
574 	error = -ENOMEM;
575 	cd = kmalloc(sizeof(*cd), GFP_KERNEL);
576 	if (!cd)
577 		goto fail;
578 	memset(cd, 0, sizeof(*cd));
579 
580 	kref_init(&cd->kref);
581 
582 	disk = alloc_disk(1);
583 	if (!disk)
584 		goto fail_free;
585 
586 	spin_lock(&sr_index_lock);
587 	minor = find_first_zero_bit(sr_index_bits, SR_DISKS);
588 	if (minor == SR_DISKS) {
589 		spin_unlock(&sr_index_lock);
590 		error = -EBUSY;
591 		goto fail_put;
592 	}
593 	__set_bit(minor, sr_index_bits);
594 	spin_unlock(&sr_index_lock);
595 
596 	disk->major = SCSI_CDROM_MAJOR;
597 	disk->first_minor = minor;
598 	sprintf(disk->disk_name, "sr%d", minor);
599 	disk->fops = &sr_bdops;
600 	disk->flags = GENHD_FL_CD;
601 
602 	cd->device = sdev;
603 	cd->disk = disk;
604 	cd->driver = &sr_template;
605 	cd->disk = disk;
606 	cd->capacity = 0x1fffff;
607 	cd->needs_sector_size = 1;
608 	cd->device->changed = 1;	/* force recheck CD type */
609 	cd->use = 1;
610 	cd->readcd_known = 0;
611 	cd->readcd_cdda = 0;
612 
613 	cd->cdi.ops = &sr_dops;
614 	cd->cdi.handle = cd;
615 	cd->cdi.mask = 0;
616 	cd->cdi.capacity = 1;
617 	sprintf(cd->cdi.name, "sr%d", minor);
618 
619 	sdev->sector_size = 2048;	/* A guess, just in case */
620 
621 	/* FIXME: need to handle a get_capabilities failure properly ?? */
622 	get_capabilities(cd);
623 	sr_vendor_init(cd);
624 
625 	snprintf(disk->devfs_name, sizeof(disk->devfs_name),
626 			"%s/cd", sdev->devfs_name);
627 	disk->driverfs_dev = &sdev->sdev_gendev;
628 	set_capacity(disk, cd->capacity);
629 	disk->private_data = &cd->driver;
630 	disk->queue = sdev->request_queue;
631 	cd->cdi.disk = disk;
632 
633 	if (register_cdrom(&cd->cdi))
634 		goto fail_put;
635 
636 	dev_set_drvdata(dev, cd);
637 	disk->flags |= GENHD_FL_REMOVABLE;
638 	add_disk(disk);
639 
640 	printk(KERN_DEBUG
641 	    "Attached scsi CD-ROM %s at scsi%d, channel %d, id %d, lun %d\n",
642 	    cd->cdi.name, sdev->host->host_no, sdev->channel,
643 	    sdev->id, sdev->lun);
644 	return 0;
645 
646 fail_put:
647 	put_disk(disk);
648 fail_free:
649 	kfree(cd);
650 fail:
651 	return error;
652 }
653 
654 
655 static void get_sectorsize(struct scsi_cd *cd)
656 {
657 	unsigned char cmd[10];
658 	unsigned char *buffer;
659 	int the_result, retries = 3;
660 	int sector_size;
661 	struct scsi_request *SRpnt = NULL;
662 	request_queue_t *queue;
663 
664 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
665 	if (!buffer)
666 		goto Enomem;
667 	SRpnt = scsi_allocate_request(cd->device, GFP_KERNEL);
668 	if (!SRpnt)
669 		goto Enomem;
670 
671 	do {
672 		cmd[0] = READ_CAPACITY;
673 		memset((void *) &cmd[1], 0, 9);
674 		/* Mark as really busy */
675 		SRpnt->sr_request->rq_status = RQ_SCSI_BUSY;
676 		SRpnt->sr_cmd_len = 0;
677 
678 		memset(buffer, 0, 8);
679 
680 		/* Do the command and wait.. */
681 		SRpnt->sr_data_direction = DMA_FROM_DEVICE;
682 		scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer,
683 			      8, SR_TIMEOUT, MAX_RETRIES);
684 
685 		the_result = SRpnt->sr_result;
686 		retries--;
687 
688 	} while (the_result && retries);
689 
690 
691 	scsi_release_request(SRpnt);
692 	SRpnt = NULL;
693 
694 	if (the_result) {
695 		cd->capacity = 0x1fffff;
696 		sector_size = 2048;	/* A guess, just in case */
697 		cd->needs_sector_size = 1;
698 	} else {
699 #if 0
700 		if (cdrom_get_last_written(&cd->cdi,
701 					   &cd->capacity))
702 #endif
703 			cd->capacity = 1 + ((buffer[0] << 24) |
704 						    (buffer[1] << 16) |
705 						    (buffer[2] << 8) |
706 						    buffer[3]);
707 		sector_size = (buffer[4] << 24) |
708 		    (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
709 		switch (sector_size) {
710 			/*
711 			 * HP 4020i CD-Recorder reports 2340 byte sectors
712 			 * Philips CD-Writers report 2352 byte sectors
713 			 *
714 			 * Use 2k sectors for them..
715 			 */
716 		case 0:
717 		case 2340:
718 		case 2352:
719 			sector_size = 2048;
720 			/* fall through */
721 		case 2048:
722 			cd->capacity *= 4;
723 			/* fall through */
724 		case 512:
725 			break;
726 		default:
727 			printk("%s: unsupported sector size %d.\n",
728 			       cd->cdi.name, sector_size);
729 			cd->capacity = 0;
730 			cd->needs_sector_size = 1;
731 		}
732 
733 		cd->device->sector_size = sector_size;
734 
735 		/*
736 		 * Add this so that we have the ability to correctly gauge
737 		 * what the device is capable of.
738 		 */
739 		cd->needs_sector_size = 0;
740 		set_capacity(cd->disk, cd->capacity);
741 	}
742 
743 	queue = cd->device->request_queue;
744 	blk_queue_hardsect_size(queue, sector_size);
745 out:
746 	kfree(buffer);
747 	return;
748 
749 Enomem:
750 	cd->capacity = 0x1fffff;
751 	sector_size = 2048;	/* A guess, just in case */
752 	cd->needs_sector_size = 1;
753 	if (SRpnt)
754 		scsi_release_request(SRpnt);
755 	goto out;
756 }
757 
758 static void get_capabilities(struct scsi_cd *cd)
759 {
760 	unsigned char *buffer;
761 	struct scsi_mode_data data;
762 	struct scsi_request *SRpnt;
763 	unsigned char cmd[MAX_COMMAND_SIZE];
764 	unsigned int the_result;
765 	int retries, rc, n;
766 
767 	static char *loadmech[] =
768 	{
769 		"caddy",
770 		"tray",
771 		"pop-up",
772 		"",
773 		"changer",
774 		"cartridge changer",
775 		"",
776 		""
777 	};
778 
779 	/* allocate a request for the TEST_UNIT_READY */
780 	SRpnt = scsi_allocate_request(cd->device, GFP_KERNEL);
781 	if (!SRpnt) {
782 		printk(KERN_WARNING "(get_capabilities:) Request allocation "
783 		       "failure.\n");
784 		return;
785 	}
786 
787 	/* allocate transfer buffer */
788 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
789 	if (!buffer) {
790 		printk(KERN_ERR "sr: out of memory.\n");
791 		scsi_release_request(SRpnt);
792 		return;
793 	}
794 
795 	/* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
796 	 * conditions are gone, or a timeout happens
797 	 */
798 	retries = 0;
799 	do {
800 		memset((void *)cmd, 0, MAX_COMMAND_SIZE);
801 		cmd[0] = TEST_UNIT_READY;
802 
803 		SRpnt->sr_cmd_len = 0;
804 		SRpnt->sr_sense_buffer[0] = 0;
805 		SRpnt->sr_sense_buffer[2] = 0;
806 		SRpnt->sr_data_direction = DMA_NONE;
807 
808 		scsi_wait_req (SRpnt, (void *) cmd, buffer,
809 			       0, SR_TIMEOUT, MAX_RETRIES);
810 
811 		the_result = SRpnt->sr_result;
812 		retries++;
813 	} while (retries < 5 &&
814 		 (!scsi_status_is_good(the_result) ||
815 		  ((driver_byte(the_result) & DRIVER_SENSE) &&
816 		   SRpnt->sr_sense_buffer[2] == UNIT_ATTENTION)));
817 
818 	/* ask for mode page 0x2a */
819 	rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128,
820 			     SR_TIMEOUT, 3, &data);
821 
822 	if (!scsi_status_is_good(rc)) {
823 		/* failed, drive doesn't have capabilities mode page */
824 		cd->cdi.speed = 1;
825 		cd->cdi.mask |= (CDC_CD_R | CDC_CD_RW | CDC_DVD_R |
826 					 CDC_DVD | CDC_DVD_RAM |
827 					 CDC_SELECT_DISC | CDC_SELECT_SPEED);
828 		scsi_release_request(SRpnt);
829 		kfree(buffer);
830 		printk("%s: scsi-1 drive\n", cd->cdi.name);
831 		return;
832 	}
833 
834 	n = data.header_length + data.block_descriptor_length;
835 	cd->cdi.speed = ((buffer[n + 8] << 8) + buffer[n + 9]) / 176;
836 	cd->readcd_known = 1;
837 	cd->readcd_cdda = buffer[n + 5] & 0x01;
838 	/* print some capability bits */
839 	printk("%s: scsi3-mmc drive: %dx/%dx %s%s%s%s%s%s\n", cd->cdi.name,
840 	       ((buffer[n + 14] << 8) + buffer[n + 15]) / 176,
841 	       cd->cdi.speed,
842 	       buffer[n + 3] & 0x01 ? "writer " : "", /* CD Writer */
843 	       buffer[n + 3] & 0x20 ? "dvd-ram " : "",
844 	       buffer[n + 2] & 0x02 ? "cd/rw " : "", /* can read rewriteable */
845 	       buffer[n + 4] & 0x20 ? "xa/form2 " : "",	/* can read xa/from2 */
846 	       buffer[n + 5] & 0x01 ? "cdda " : "", /* can read audio data */
847 	       loadmech[buffer[n + 6] >> 5]);
848 	if ((buffer[n + 6] >> 5) == 0)
849 		/* caddy drives can't close tray... */
850 		cd->cdi.mask |= CDC_CLOSE_TRAY;
851 	if ((buffer[n + 2] & 0x8) == 0)
852 		/* not a DVD drive */
853 		cd->cdi.mask |= CDC_DVD;
854 	if ((buffer[n + 3] & 0x20) == 0)
855 		/* can't write DVD-RAM media */
856 		cd->cdi.mask |= CDC_DVD_RAM;
857 	if ((buffer[n + 3] & 0x10) == 0)
858 		/* can't write DVD-R media */
859 		cd->cdi.mask |= CDC_DVD_R;
860 	if ((buffer[n + 3] & 0x2) == 0)
861 		/* can't write CD-RW media */
862 		cd->cdi.mask |= CDC_CD_RW;
863 	if ((buffer[n + 3] & 0x1) == 0)
864 		/* can't write CD-R media */
865 		cd->cdi.mask |= CDC_CD_R;
866 	if ((buffer[n + 6] & 0x8) == 0)
867 		/* can't eject */
868 		cd->cdi.mask |= CDC_OPEN_TRAY;
869 
870 	if ((buffer[n + 6] >> 5) == mechtype_individual_changer ||
871 	    (buffer[n + 6] >> 5) == mechtype_cartridge_changer)
872 		cd->cdi.capacity =
873 		    cdrom_number_of_slots(&cd->cdi);
874 	if (cd->cdi.capacity <= 1)
875 		/* not a changer */
876 		cd->cdi.mask |= CDC_SELECT_DISC;
877 	/*else    I don't think it can close its tray
878 		cd->cdi.mask |= CDC_CLOSE_TRAY; */
879 
880 	/*
881 	 * if DVD-RAM, MRW-W or CD-RW, we are randomly writable
882 	 */
883 	if ((cd->cdi.mask & (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) !=
884 			(CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) {
885 		cd->device->writeable = 1;
886 	}
887 
888 	scsi_release_request(SRpnt);
889 	kfree(buffer);
890 }
891 
892 /*
893  * sr_packet() is the entry point for the generic commands generated
894  * by the Uniform CD-ROM layer.
895  */
896 static int sr_packet(struct cdrom_device_info *cdi,
897 		struct packet_command *cgc)
898 {
899 	if (cgc->timeout <= 0)
900 		cgc->timeout = IOCTL_TIMEOUT;
901 
902 	sr_do_ioctl(cdi->handle, cgc);
903 
904 	return cgc->stat;
905 }
906 
907 /**
908  *	sr_kref_release - Called to free the scsi_cd structure
909  *	@kref: pointer to embedded kref
910  *
911  *	sr_ref_sem must be held entering this routine.  Because it is
912  *	called on last put, you should always use the scsi_cd_get()
913  *	scsi_cd_put() helpers which manipulate the semaphore directly
914  *	and never do a direct kref_put().
915  **/
916 static void sr_kref_release(struct kref *kref)
917 {
918 	struct scsi_cd *cd = container_of(kref, struct scsi_cd, kref);
919 	struct gendisk *disk = cd->disk;
920 
921 	spin_lock(&sr_index_lock);
922 	clear_bit(disk->first_minor, sr_index_bits);
923 	spin_unlock(&sr_index_lock);
924 
925 	unregister_cdrom(&cd->cdi);
926 
927 	disk->private_data = NULL;
928 
929 	put_disk(disk);
930 
931 	kfree(cd);
932 }
933 
934 static int sr_remove(struct device *dev)
935 {
936 	struct scsi_cd *cd = dev_get_drvdata(dev);
937 
938 	del_gendisk(cd->disk);
939 
940 	down(&sr_ref_sem);
941 	kref_put(&cd->kref, sr_kref_release);
942 	up(&sr_ref_sem);
943 
944 	return 0;
945 }
946 
947 static int __init init_sr(void)
948 {
949 	int rc;
950 
951 	rc = register_blkdev(SCSI_CDROM_MAJOR, "sr");
952 	if (rc)
953 		return rc;
954 	return scsi_register_driver(&sr_template.gendrv);
955 }
956 
957 static void __exit exit_sr(void)
958 {
959 	scsi_unregister_driver(&sr_template.gendrv);
960 	unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
961 }
962 
963 module_init(init_sr);
964 module_exit(exit_sr);
965 MODULE_LICENSE("GPL");
966