xref: /linux/drivers/scsi/sr.c (revision 54a8a2220c936a47840c9a3d74910c5a56fae2ed)
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_cmnd.h>
54 #include <scsi/scsi_eh.h>
55 #include <scsi/scsi_host.h>
56 #include <scsi/scsi_ioctl.h>	/* For the door lock/unlock commands */
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 		get_sectorsize(cd);
203 	}
204 	return retval;
205 }
206 
207 /*
208  * rw_intr is the interrupt routine for the device driver.
209  *
210  * It will be notified on the end of a SCSI read / write, and will take on
211  * of several actions based on success or failure.
212  */
213 static void rw_intr(struct scsi_cmnd * SCpnt)
214 {
215 	int result = SCpnt->result;
216 	int this_count = SCpnt->bufflen;
217 	int good_bytes = (result == 0 ? this_count : 0);
218 	int block_sectors = 0;
219 	long error_sector;
220 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
221 
222 #ifdef DEBUG
223 	printk("sr.c done: %x\n", result);
224 #endif
225 
226 	/*
227 	 * Handle MEDIUM ERRORs or VOLUME OVERFLOWs that indicate partial
228 	 * success.  Since this is a relatively rare error condition, no
229 	 * care is taken to avoid unnecessary additional work such as
230 	 * memcpy's that could be avoided.
231 	 */
232 	if (driver_byte(result) != 0 &&		/* An error occurred */
233 	    (SCpnt->sense_buffer[0] & 0x7f) == 0x70) { /* Sense current */
234 		switch (SCpnt->sense_buffer[2]) {
235 		case MEDIUM_ERROR:
236 		case VOLUME_OVERFLOW:
237 		case ILLEGAL_REQUEST:
238 			if (!(SCpnt->sense_buffer[0] & 0x90))
239 				break;
240 			if (!blk_fs_request(SCpnt->request))
241 				break;
242 			error_sector = (SCpnt->sense_buffer[3] << 24) |
243 				(SCpnt->sense_buffer[4] << 16) |
244 				(SCpnt->sense_buffer[5] << 8) |
245 				SCpnt->sense_buffer[6];
246 			if (SCpnt->request->bio != NULL)
247 				block_sectors =
248 					bio_sectors(SCpnt->request->bio);
249 			if (block_sectors < 4)
250 				block_sectors = 4;
251 			if (cd->device->sector_size == 2048)
252 				error_sector <<= 2;
253 			error_sector &= ~(block_sectors - 1);
254 			good_bytes = (error_sector - SCpnt->request->sector) << 9;
255 			if (good_bytes < 0 || good_bytes >= this_count)
256 				good_bytes = 0;
257 			/*
258 			 * The SCSI specification allows for the value
259 			 * returned by READ CAPACITY to be up to 75 2K
260 			 * sectors past the last readable block.
261 			 * Therefore, if we hit a medium error within the
262 			 * last 75 2K sectors, we decrease the saved size
263 			 * value.
264 			 */
265 			if (error_sector < get_capacity(cd->disk) &&
266 			    cd->capacity - error_sector < 4 * 75)
267 				set_capacity(cd->disk, error_sector);
268 			break;
269 
270 		case RECOVERED_ERROR:
271 
272 			/*
273 			 * An error occured, but it recovered.  Inform the
274 			 * user, but make sure that it's not treated as a
275 			 * hard error.
276 			 */
277 			scsi_print_sense("sr", SCpnt);
278 			SCpnt->result = 0;
279 			SCpnt->sense_buffer[0] = 0x0;
280 			good_bytes = this_count;
281 			break;
282 
283 		default:
284 			break;
285 		}
286 	}
287 
288 	/*
289 	 * This calls the generic completion function, now that we know
290 	 * how many actual sectors finished, and how many sectors we need
291 	 * to say have failed.
292 	 */
293 	scsi_io_completion(SCpnt, good_bytes, block_sectors << 9);
294 }
295 
296 static int sr_init_command(struct scsi_cmnd * SCpnt)
297 {
298 	int block=0, this_count, s_size, timeout = SR_TIMEOUT;
299 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
300 
301 	SCSI_LOG_HLQUEUE(1, printk("Doing sr request, dev = %s, block = %d\n",
302 				cd->disk->disk_name, block));
303 
304 	if (!cd->device || !scsi_device_online(cd->device)) {
305 		SCSI_LOG_HLQUEUE(2, printk("Finishing %ld sectors\n",
306 					SCpnt->request->nr_sectors));
307 		SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
308 		return 0;
309 	}
310 
311 	if (cd->device->changed) {
312 		/*
313 		 * quietly refuse to do anything to a changed disc until the
314 		 * changed bit has been reset
315 		 */
316 		return 0;
317 	}
318 
319 	/*
320 	 * these are already setup, just copy cdb basically
321 	 */
322 	if (SCpnt->request->flags & REQ_BLOCK_PC) {
323 		struct request *rq = SCpnt->request;
324 
325 		if (sizeof(rq->cmd) > sizeof(SCpnt->cmnd))
326 			return 0;
327 
328 		memcpy(SCpnt->cmnd, rq->cmd, sizeof(SCpnt->cmnd));
329 		SCpnt->cmd_len = rq->cmd_len;
330 		if (!rq->data_len)
331 			SCpnt->sc_data_direction = DMA_NONE;
332 		else if (rq_data_dir(rq) == WRITE)
333 			SCpnt->sc_data_direction = DMA_TO_DEVICE;
334 		else
335 			SCpnt->sc_data_direction = DMA_FROM_DEVICE;
336 
337 		this_count = rq->data_len;
338 		if (rq->timeout)
339 			timeout = rq->timeout;
340 
341 		SCpnt->transfersize = rq->data_len;
342 		goto queue;
343 	}
344 
345 	if (!(SCpnt->request->flags & REQ_CMD)) {
346 		blk_dump_rq_flags(SCpnt->request, "sr unsup command");
347 		return 0;
348 	}
349 
350 	/*
351 	 * we do lazy blocksize switching (when reading XA sectors,
352 	 * see CDROMREADMODE2 ioctl)
353 	 */
354 	s_size = cd->device->sector_size;
355 	if (s_size > 2048) {
356 		if (!in_interrupt())
357 			sr_set_blocklength(cd, 2048);
358 		else
359 			printk("sr: can't switch blocksize: in interrupt\n");
360 	}
361 
362 	if (s_size != 512 && s_size != 1024 && s_size != 2048) {
363 		printk("sr: bad sector size %d\n", s_size);
364 		return 0;
365 	}
366 
367 	if (rq_data_dir(SCpnt->request) == WRITE) {
368 		if (!cd->device->writeable)
369 			return 0;
370 		SCpnt->cmnd[0] = WRITE_10;
371 		SCpnt->sc_data_direction = DMA_TO_DEVICE;
372  	 	cd->cdi.media_written = 1;
373 	} else if (rq_data_dir(SCpnt->request) == READ) {
374 		SCpnt->cmnd[0] = READ_10;
375 		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
376 	} else {
377 		blk_dump_rq_flags(SCpnt->request, "Unknown sr command");
378 		return 0;
379 	}
380 
381 	{
382 		struct scatterlist *sg = SCpnt->request_buffer;
383 		int i, size = 0;
384 		for (i = 0; i < SCpnt->use_sg; i++)
385 			size += sg[i].length;
386 
387 		if (size != SCpnt->request_bufflen && SCpnt->use_sg) {
388 			printk(KERN_ERR "sr: mismatch count %d, bytes %d\n",
389 					size, SCpnt->request_bufflen);
390 			if (SCpnt->request_bufflen > size)
391 				SCpnt->request_bufflen = SCpnt->bufflen = size;
392 		}
393 	}
394 
395 	/*
396 	 * request doesn't start on hw block boundary, add scatter pads
397 	 */
398 	if (((unsigned int)SCpnt->request->sector % (s_size >> 9)) ||
399 	    (SCpnt->request_bufflen % s_size)) {
400 		printk("sr: unaligned transfer\n");
401 		return 0;
402 	}
403 
404 	this_count = (SCpnt->request_bufflen >> 9) / (s_size >> 9);
405 
406 
407 	SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n",
408 				cd->cdi.name,
409 				(rq_data_dir(SCpnt->request) == WRITE) ?
410 					"writing" : "reading",
411 				this_count, SCpnt->request->nr_sectors));
412 
413 	SCpnt->cmnd[1] = 0;
414 	block = (unsigned int)SCpnt->request->sector / (s_size >> 9);
415 
416 	if (this_count > 0xffff) {
417 		this_count = 0xffff;
418 		SCpnt->request_bufflen = SCpnt->bufflen =
419 				this_count * s_size;
420 	}
421 
422 	SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
423 	SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
424 	SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
425 	SCpnt->cmnd[5] = (unsigned char) block & 0xff;
426 	SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
427 	SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
428 	SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
429 
430 	/*
431 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
432 	 * host adapter, it's safe to assume that we can at least transfer
433 	 * this many bytes between each connect / disconnect.
434 	 */
435 	SCpnt->transfersize = cd->device->sector_size;
436 	SCpnt->underflow = this_count << 9;
437 
438 queue:
439 	SCpnt->allowed = MAX_RETRIES;
440 	SCpnt->timeout_per_command = timeout;
441 
442 	/*
443 	 * This is the completion routine we use.  This is matched in terms
444 	 * of capability to this function.
445 	 */
446 	SCpnt->done = rw_intr;
447 
448 	/*
449 	 * This indicates that the command is ready from our end to be
450 	 * queued.
451 	 */
452 	return 1;
453 }
454 
455 static int sr_block_open(struct inode *inode, struct file *file)
456 {
457 	struct gendisk *disk = inode->i_bdev->bd_disk;
458 	struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
459 	int ret = 0;
460 
461 	if(!(cd = scsi_cd_get(disk)))
462 		return -ENXIO;
463 
464 	if((ret = cdrom_open(&cd->cdi, inode, file)) != 0)
465 		scsi_cd_put(cd);
466 
467 	return ret;
468 }
469 
470 static int sr_block_release(struct inode *inode, struct file *file)
471 {
472 	int ret;
473 	struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
474 	ret = cdrom_release(&cd->cdi, file);
475 	if(ret)
476 		return ret;
477 
478 	scsi_cd_put(cd);
479 
480 	return 0;
481 }
482 
483 static int sr_block_ioctl(struct inode *inode, struct file *file, unsigned cmd,
484 			  unsigned long arg)
485 {
486 	struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
487 	struct scsi_device *sdev = cd->device;
488 
489         /*
490          * Send SCSI addressing ioctls directly to mid level, send other
491          * ioctls to cdrom/block level.
492          */
493         switch (cmd) {
494                 case SCSI_IOCTL_GET_IDLUN:
495                 case SCSI_IOCTL_GET_BUS_NUMBER:
496                         return scsi_ioctl(sdev, cmd, (void __user *)arg);
497 	}
498 	return cdrom_ioctl(file, &cd->cdi, inode, cmd, arg);
499 }
500 
501 static int sr_block_media_changed(struct gendisk *disk)
502 {
503 	struct scsi_cd *cd = scsi_cd(disk);
504 	return cdrom_media_changed(&cd->cdi);
505 }
506 
507 static struct block_device_operations sr_bdops =
508 {
509 	.owner		= THIS_MODULE,
510 	.open		= sr_block_open,
511 	.release	= sr_block_release,
512 	.ioctl		= sr_block_ioctl,
513 	.media_changed	= sr_block_media_changed,
514 	/*
515 	 * No compat_ioctl for now because sr_block_ioctl never
516 	 * seems to pass arbitary ioctls down to host drivers.
517 	 */
518 };
519 
520 static int sr_open(struct cdrom_device_info *cdi, int purpose)
521 {
522 	struct scsi_cd *cd = cdi->handle;
523 	struct scsi_device *sdev = cd->device;
524 	int retval;
525 
526 	/*
527 	 * If the device is in error recovery, wait until it is done.
528 	 * If the device is offline, then disallow any access to it.
529 	 */
530 	retval = -ENXIO;
531 	if (!scsi_block_when_processing_errors(sdev))
532 		goto error_out;
533 
534 	return 0;
535 
536 error_out:
537 	return retval;
538 }
539 
540 static void sr_release(struct cdrom_device_info *cdi)
541 {
542 	struct scsi_cd *cd = cdi->handle;
543 
544 	if (cd->device->sector_size > 2048)
545 		sr_set_blocklength(cd, 2048);
546 
547 }
548 
549 static int sr_probe(struct device *dev)
550 {
551 	struct scsi_device *sdev = to_scsi_device(dev);
552 	struct gendisk *disk;
553 	struct scsi_cd *cd;
554 	int minor, error;
555 
556 	error = -ENODEV;
557 	if (sdev->type != TYPE_ROM && sdev->type != TYPE_WORM)
558 		goto fail;
559 
560 	error = -ENOMEM;
561 	cd = kmalloc(sizeof(*cd), GFP_KERNEL);
562 	if (!cd)
563 		goto fail;
564 	memset(cd, 0, sizeof(*cd));
565 
566 	kref_init(&cd->kref);
567 
568 	disk = alloc_disk(1);
569 	if (!disk)
570 		goto fail_free;
571 
572 	spin_lock(&sr_index_lock);
573 	minor = find_first_zero_bit(sr_index_bits, SR_DISKS);
574 	if (minor == SR_DISKS) {
575 		spin_unlock(&sr_index_lock);
576 		error = -EBUSY;
577 		goto fail_put;
578 	}
579 	__set_bit(minor, sr_index_bits);
580 	spin_unlock(&sr_index_lock);
581 
582 	disk->major = SCSI_CDROM_MAJOR;
583 	disk->first_minor = minor;
584 	sprintf(disk->disk_name, "sr%d", minor);
585 	disk->fops = &sr_bdops;
586 	disk->flags = GENHD_FL_CD;
587 
588 	cd->device = sdev;
589 	cd->disk = disk;
590 	cd->driver = &sr_template;
591 	cd->disk = disk;
592 	cd->capacity = 0x1fffff;
593 	cd->device->changed = 1;	/* force recheck CD type */
594 	cd->use = 1;
595 	cd->readcd_known = 0;
596 	cd->readcd_cdda = 0;
597 
598 	cd->cdi.ops = &sr_dops;
599 	cd->cdi.handle = cd;
600 	cd->cdi.mask = 0;
601 	cd->cdi.capacity = 1;
602 	sprintf(cd->cdi.name, "sr%d", minor);
603 
604 	sdev->sector_size = 2048;	/* A guess, just in case */
605 
606 	/* FIXME: need to handle a get_capabilities failure properly ?? */
607 	get_capabilities(cd);
608 	sr_vendor_init(cd);
609 
610 	snprintf(disk->devfs_name, sizeof(disk->devfs_name),
611 			"%s/cd", sdev->devfs_name);
612 	disk->driverfs_dev = &sdev->sdev_gendev;
613 	set_capacity(disk, cd->capacity);
614 	disk->private_data = &cd->driver;
615 	disk->queue = sdev->request_queue;
616 	cd->cdi.disk = disk;
617 
618 	if (register_cdrom(&cd->cdi))
619 		goto fail_put;
620 
621 	dev_set_drvdata(dev, cd);
622 	disk->flags |= GENHD_FL_REMOVABLE;
623 	add_disk(disk);
624 
625 	printk(KERN_DEBUG
626 	    "Attached scsi CD-ROM %s at scsi%d, channel %d, id %d, lun %d\n",
627 	    cd->cdi.name, sdev->host->host_no, sdev->channel,
628 	    sdev->id, sdev->lun);
629 	return 0;
630 
631 fail_put:
632 	put_disk(disk);
633 fail_free:
634 	kfree(cd);
635 fail:
636 	return error;
637 }
638 
639 
640 static void get_sectorsize(struct scsi_cd *cd)
641 {
642 	unsigned char cmd[10];
643 	unsigned char *buffer;
644 	int the_result, retries = 3;
645 	int sector_size;
646 	request_queue_t *queue;
647 
648 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
649 	if (!buffer)
650 		goto Enomem;
651 
652 	do {
653 		cmd[0] = READ_CAPACITY;
654 		memset((void *) &cmd[1], 0, 9);
655 		memset(buffer, 0, 8);
656 
657 		/* Do the command and wait.. */
658 		the_result = scsi_execute_req(cd->device, cmd, DMA_FROM_DEVICE,
659 					      buffer, 8, NULL, SR_TIMEOUT,
660 					      MAX_RETRIES);
661 
662 		retries--;
663 
664 	} while (the_result && retries);
665 
666 
667 	if (the_result) {
668 		cd->capacity = 0x1fffff;
669 		sector_size = 2048;	/* A guess, just in case */
670 	} else {
671 #if 0
672 		if (cdrom_get_last_written(&cd->cdi,
673 					   &cd->capacity))
674 #endif
675 			cd->capacity = 1 + ((buffer[0] << 24) |
676 						    (buffer[1] << 16) |
677 						    (buffer[2] << 8) |
678 						    buffer[3]);
679 		sector_size = (buffer[4] << 24) |
680 		    (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
681 		switch (sector_size) {
682 			/*
683 			 * HP 4020i CD-Recorder reports 2340 byte sectors
684 			 * Philips CD-Writers report 2352 byte sectors
685 			 *
686 			 * Use 2k sectors for them..
687 			 */
688 		case 0:
689 		case 2340:
690 		case 2352:
691 			sector_size = 2048;
692 			/* fall through */
693 		case 2048:
694 			cd->capacity *= 4;
695 			/* fall through */
696 		case 512:
697 			break;
698 		default:
699 			printk("%s: unsupported sector size %d.\n",
700 			       cd->cdi.name, sector_size);
701 			cd->capacity = 0;
702 		}
703 
704 		cd->device->sector_size = sector_size;
705 
706 		/*
707 		 * Add this so that we have the ability to correctly gauge
708 		 * what the device is capable of.
709 		 */
710 		set_capacity(cd->disk, cd->capacity);
711 	}
712 
713 	queue = cd->device->request_queue;
714 	blk_queue_hardsect_size(queue, sector_size);
715 out:
716 	kfree(buffer);
717 	return;
718 
719 Enomem:
720 	cd->capacity = 0x1fffff;
721 	cd->device->sector_size = 2048;	/* A guess, just in case */
722 	goto out;
723 }
724 
725 static void get_capabilities(struct scsi_cd *cd)
726 {
727 	unsigned char *buffer;
728 	struct scsi_mode_data data;
729 	unsigned char cmd[MAX_COMMAND_SIZE];
730 	struct scsi_sense_hdr sshdr;
731 	unsigned int the_result;
732 	int retries, rc, n;
733 
734 	static char *loadmech[] =
735 	{
736 		"caddy",
737 		"tray",
738 		"pop-up",
739 		"",
740 		"changer",
741 		"cartridge changer",
742 		"",
743 		""
744 	};
745 
746 
747 	/* allocate transfer buffer */
748 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
749 	if (!buffer) {
750 		printk(KERN_ERR "sr: out of memory.\n");
751 		return;
752 	}
753 
754 	/* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
755 	 * conditions are gone, or a timeout happens
756 	 */
757 	retries = 0;
758 	do {
759 		memset((void *)cmd, 0, MAX_COMMAND_SIZE);
760 		cmd[0] = TEST_UNIT_READY;
761 
762 		the_result = scsi_execute_req (cd->device, cmd, DMA_NONE, NULL,
763 					       0, &sshdr, SR_TIMEOUT,
764 					       MAX_RETRIES);
765 
766 		retries++;
767 	} while (retries < 5 &&
768 		 (!scsi_status_is_good(the_result) ||
769 		  (scsi_sense_valid(&sshdr) &&
770 		   sshdr.sense_key == UNIT_ATTENTION)));
771 
772 	/* ask for mode page 0x2a */
773 	rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128,
774 			     SR_TIMEOUT, 3, &data, NULL);
775 
776 	if (!scsi_status_is_good(rc)) {
777 		/* failed, drive doesn't have capabilities mode page */
778 		cd->cdi.speed = 1;
779 		cd->cdi.mask |= (CDC_CD_R | CDC_CD_RW | CDC_DVD_R |
780 					 CDC_DVD | CDC_DVD_RAM |
781 					 CDC_SELECT_DISC | CDC_SELECT_SPEED);
782 		kfree(buffer);
783 		printk("%s: scsi-1 drive\n", cd->cdi.name);
784 		return;
785 	}
786 
787 	n = data.header_length + data.block_descriptor_length;
788 	cd->cdi.speed = ((buffer[n + 8] << 8) + buffer[n + 9]) / 176;
789 	cd->readcd_known = 1;
790 	cd->readcd_cdda = buffer[n + 5] & 0x01;
791 	/* print some capability bits */
792 	printk("%s: scsi3-mmc drive: %dx/%dx %s%s%s%s%s%s\n", cd->cdi.name,
793 	       ((buffer[n + 14] << 8) + buffer[n + 15]) / 176,
794 	       cd->cdi.speed,
795 	       buffer[n + 3] & 0x01 ? "writer " : "", /* CD Writer */
796 	       buffer[n + 3] & 0x20 ? "dvd-ram " : "",
797 	       buffer[n + 2] & 0x02 ? "cd/rw " : "", /* can read rewriteable */
798 	       buffer[n + 4] & 0x20 ? "xa/form2 " : "",	/* can read xa/from2 */
799 	       buffer[n + 5] & 0x01 ? "cdda " : "", /* can read audio data */
800 	       loadmech[buffer[n + 6] >> 5]);
801 	if ((buffer[n + 6] >> 5) == 0)
802 		/* caddy drives can't close tray... */
803 		cd->cdi.mask |= CDC_CLOSE_TRAY;
804 	if ((buffer[n + 2] & 0x8) == 0)
805 		/* not a DVD drive */
806 		cd->cdi.mask |= CDC_DVD;
807 	if ((buffer[n + 3] & 0x20) == 0)
808 		/* can't write DVD-RAM media */
809 		cd->cdi.mask |= CDC_DVD_RAM;
810 	if ((buffer[n + 3] & 0x10) == 0)
811 		/* can't write DVD-R media */
812 		cd->cdi.mask |= CDC_DVD_R;
813 	if ((buffer[n + 3] & 0x2) == 0)
814 		/* can't write CD-RW media */
815 		cd->cdi.mask |= CDC_CD_RW;
816 	if ((buffer[n + 3] & 0x1) == 0)
817 		/* can't write CD-R media */
818 		cd->cdi.mask |= CDC_CD_R;
819 	if ((buffer[n + 6] & 0x8) == 0)
820 		/* can't eject */
821 		cd->cdi.mask |= CDC_OPEN_TRAY;
822 
823 	if ((buffer[n + 6] >> 5) == mechtype_individual_changer ||
824 	    (buffer[n + 6] >> 5) == mechtype_cartridge_changer)
825 		cd->cdi.capacity =
826 		    cdrom_number_of_slots(&cd->cdi);
827 	if (cd->cdi.capacity <= 1)
828 		/* not a changer */
829 		cd->cdi.mask |= CDC_SELECT_DISC;
830 	/*else    I don't think it can close its tray
831 		cd->cdi.mask |= CDC_CLOSE_TRAY; */
832 
833 	/*
834 	 * if DVD-RAM, MRW-W or CD-RW, we are randomly writable
835 	 */
836 	if ((cd->cdi.mask & (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) !=
837 			(CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) {
838 		cd->device->writeable = 1;
839 	}
840 
841 	kfree(buffer);
842 }
843 
844 /*
845  * sr_packet() is the entry point for the generic commands generated
846  * by the Uniform CD-ROM layer.
847  */
848 static int sr_packet(struct cdrom_device_info *cdi,
849 		struct packet_command *cgc)
850 {
851 	if (cgc->timeout <= 0)
852 		cgc->timeout = IOCTL_TIMEOUT;
853 
854 	sr_do_ioctl(cdi->handle, cgc);
855 
856 	return cgc->stat;
857 }
858 
859 /**
860  *	sr_kref_release - Called to free the scsi_cd structure
861  *	@kref: pointer to embedded kref
862  *
863  *	sr_ref_sem must be held entering this routine.  Because it is
864  *	called on last put, you should always use the scsi_cd_get()
865  *	scsi_cd_put() helpers which manipulate the semaphore directly
866  *	and never do a direct kref_put().
867  **/
868 static void sr_kref_release(struct kref *kref)
869 {
870 	struct scsi_cd *cd = container_of(kref, struct scsi_cd, kref);
871 	struct gendisk *disk = cd->disk;
872 
873 	spin_lock(&sr_index_lock);
874 	clear_bit(disk->first_minor, sr_index_bits);
875 	spin_unlock(&sr_index_lock);
876 
877 	unregister_cdrom(&cd->cdi);
878 
879 	disk->private_data = NULL;
880 
881 	put_disk(disk);
882 
883 	kfree(cd);
884 }
885 
886 static int sr_remove(struct device *dev)
887 {
888 	struct scsi_cd *cd = dev_get_drvdata(dev);
889 
890 	del_gendisk(cd->disk);
891 
892 	down(&sr_ref_sem);
893 	kref_put(&cd->kref, sr_kref_release);
894 	up(&sr_ref_sem);
895 
896 	return 0;
897 }
898 
899 static int __init init_sr(void)
900 {
901 	int rc;
902 
903 	rc = register_blkdev(SCSI_CDROM_MAJOR, "sr");
904 	if (rc)
905 		return rc;
906 	return scsi_register_driver(&sr_template.gendrv);
907 }
908 
909 static void __exit exit_sr(void)
910 {
911 	scsi_unregister_driver(&sr_template.gendrv);
912 	unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
913 }
914 
915 module_init(init_sr);
916 module_exit(exit_sr);
917 MODULE_LICENSE("GPL");
918