xref: /openbmc/linux/drivers/scsi/sr.c (revision b04b4f78)
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/mm.h>
39 #include <linux/bio.h>
40 #include <linux/string.h>
41 #include <linux/errno.h>
42 #include <linux/cdrom.h>
43 #include <linux/interrupt.h>
44 #include <linux/init.h>
45 #include <linux/blkdev.h>
46 #include <linux/mutex.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 MODULE_DESCRIPTION("SCSI cdrom (sr) driver");
63 MODULE_LICENSE("GPL");
64 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_CDROM_MAJOR);
65 MODULE_ALIAS_SCSI_DEVICE(TYPE_ROM);
66 MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);
67 
68 #define SR_DISKS	256
69 
70 #define SR_CAPABILITIES \
71 	(CDC_CLOSE_TRAY|CDC_OPEN_TRAY|CDC_LOCK|CDC_SELECT_SPEED| \
72 	 CDC_SELECT_DISC|CDC_MULTI_SESSION|CDC_MCN|CDC_MEDIA_CHANGED| \
73 	 CDC_PLAY_AUDIO|CDC_RESET|CDC_DRIVE_STATUS| \
74 	 CDC_CD_R|CDC_CD_RW|CDC_DVD|CDC_DVD_R|CDC_DVD_RAM|CDC_GENERIC_PACKET| \
75 	 CDC_MRW|CDC_MRW_W|CDC_RAM)
76 
77 static int sr_probe(struct device *);
78 static int sr_remove(struct device *);
79 static int sr_done(struct scsi_cmnd *);
80 
81 static struct scsi_driver sr_template = {
82 	.owner			= THIS_MODULE,
83 	.gendrv = {
84 		.name   	= "sr",
85 		.probe		= sr_probe,
86 		.remove		= sr_remove,
87 	},
88 	.done			= sr_done,
89 };
90 
91 static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
92 static DEFINE_SPINLOCK(sr_index_lock);
93 
94 /* This semaphore is used to mediate the 0->1 reference get in the
95  * face of object destruction (i.e. we can't allow a get on an
96  * object after last put) */
97 static DEFINE_MUTEX(sr_ref_mutex);
98 
99 static int sr_open(struct cdrom_device_info *, int);
100 static void sr_release(struct cdrom_device_info *);
101 
102 static void get_sectorsize(struct scsi_cd *);
103 static void get_capabilities(struct scsi_cd *);
104 
105 static int sr_media_change(struct cdrom_device_info *, int);
106 static int sr_packet(struct cdrom_device_info *, struct packet_command *);
107 
108 static struct cdrom_device_ops sr_dops = {
109 	.open			= sr_open,
110 	.release	 	= sr_release,
111 	.drive_status	 	= sr_drive_status,
112 	.media_changed		= sr_media_change,
113 	.tray_move		= sr_tray_move,
114 	.lock_door		= sr_lock_door,
115 	.select_speed		= sr_select_speed,
116 	.get_last_session	= sr_get_last_session,
117 	.get_mcn		= sr_get_mcn,
118 	.reset			= sr_reset,
119 	.audio_ioctl		= sr_audio_ioctl,
120 	.capability		= SR_CAPABILITIES,
121 	.generic_packet		= sr_packet,
122 };
123 
124 static void sr_kref_release(struct kref *kref);
125 
126 static inline struct scsi_cd *scsi_cd(struct gendisk *disk)
127 {
128 	return container_of(disk->private_data, struct scsi_cd, driver);
129 }
130 
131 /*
132  * The get and put routines for the struct scsi_cd.  Note this entity
133  * has a scsi_device pointer and owns a reference to this.
134  */
135 static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk)
136 {
137 	struct scsi_cd *cd = NULL;
138 
139 	mutex_lock(&sr_ref_mutex);
140 	if (disk->private_data == NULL)
141 		goto out;
142 	cd = scsi_cd(disk);
143 	kref_get(&cd->kref);
144 	if (scsi_device_get(cd->device))
145 		goto out_put;
146 	goto out;
147 
148  out_put:
149 	kref_put(&cd->kref, sr_kref_release);
150 	cd = NULL;
151  out:
152 	mutex_unlock(&sr_ref_mutex);
153 	return cd;
154 }
155 
156 static void scsi_cd_put(struct scsi_cd *cd)
157 {
158 	struct scsi_device *sdev = cd->device;
159 
160 	mutex_lock(&sr_ref_mutex);
161 	kref_put(&cd->kref, sr_kref_release);
162 	scsi_device_put(sdev);
163 	mutex_unlock(&sr_ref_mutex);
164 }
165 
166 /* identical to scsi_test_unit_ready except that it doesn't
167  * eat the NOT_READY returns for removable media */
168 int sr_test_unit_ready(struct scsi_device *sdev, struct scsi_sense_hdr *sshdr)
169 {
170 	int retries = MAX_RETRIES;
171 	int the_result;
172 	u8 cmd[] = {TEST_UNIT_READY, 0, 0, 0, 0, 0 };
173 
174 	/* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
175 	 * conditions are gone, or a timeout happens
176 	 */
177 	do {
178 		the_result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL,
179 					      0, sshdr, SR_TIMEOUT,
180 					      retries--, NULL);
181 		if (scsi_sense_valid(sshdr) &&
182 		    sshdr->sense_key == UNIT_ATTENTION)
183 			sdev->changed = 1;
184 
185 	} while (retries > 0 &&
186 		 (!scsi_status_is_good(the_result) ||
187 		  (scsi_sense_valid(sshdr) &&
188 		   sshdr->sense_key == UNIT_ATTENTION)));
189 	return the_result;
190 }
191 
192 /*
193  * This function checks to see if the media has been changed in the
194  * CDROM drive.  It is possible that we have already sensed a change,
195  * or the drive may have sensed one and not yet reported it.  We must
196  * be ready for either case. This function always reports the current
197  * value of the changed bit.  If flag is 0, then the changed bit is reset.
198  * This function could be done as an ioctl, but we would need to have
199  * an inode for that to work, and we do not always have one.
200  */
201 
202 static int sr_media_change(struct cdrom_device_info *cdi, int slot)
203 {
204 	struct scsi_cd *cd = cdi->handle;
205 	int retval;
206 	struct scsi_sense_hdr *sshdr;
207 
208 	if (CDSL_CURRENT != slot) {
209 		/* no changer support */
210 		return -EINVAL;
211 	}
212 
213 	sshdr =  kzalloc(sizeof(*sshdr), GFP_KERNEL);
214 	retval = sr_test_unit_ready(cd->device, sshdr);
215 	if (retval || (scsi_sense_valid(sshdr) &&
216 		       /* 0x3a is medium not present */
217 		       sshdr->asc == 0x3a)) {
218 		/* Media not present or unable to test, unit probably not
219 		 * ready. This usually means there is no disc in the drive.
220 		 * Mark as changed, and we will figure it out later once
221 		 * the drive is available again.
222 		 */
223 		cd->device->changed = 1;
224 		/* This will force a flush, if called from check_disk_change */
225 		retval = 1;
226 		goto out;
227 	};
228 
229 	retval = cd->device->changed;
230 	cd->device->changed = 0;
231 	/* If the disk changed, the capacity will now be different,
232 	 * so we force a re-read of this information */
233 	if (retval) {
234 		/* check multisession offset etc */
235 		sr_cd_check(cdi);
236 		get_sectorsize(cd);
237 	}
238 
239 out:
240 	/* Notify userspace, that media has changed. */
241 	if (retval != cd->previous_state)
242 		sdev_evt_send_simple(cd->device, SDEV_EVT_MEDIA_CHANGE,
243 				     GFP_KERNEL);
244 	cd->previous_state = retval;
245 	kfree(sshdr);
246 
247 	return retval;
248 }
249 
250 /*
251  * sr_done is the interrupt routine for the device driver.
252  *
253  * It will be notified on the end of a SCSI read / write, and will take one
254  * of several actions based on success or failure.
255  */
256 static int sr_done(struct scsi_cmnd *SCpnt)
257 {
258 	int result = SCpnt->result;
259 	int this_count = scsi_bufflen(SCpnt);
260 	int good_bytes = (result == 0 ? this_count : 0);
261 	int block_sectors = 0;
262 	long error_sector;
263 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
264 
265 #ifdef DEBUG
266 	printk("sr.c done: %x\n", result);
267 #endif
268 
269 	/*
270 	 * Handle MEDIUM ERRORs or VOLUME OVERFLOWs that indicate partial
271 	 * success.  Since this is a relatively rare error condition, no
272 	 * care is taken to avoid unnecessary additional work such as
273 	 * memcpy's that could be avoided.
274 	 */
275 	if (driver_byte(result) != 0 &&		/* An error occurred */
276 	    (SCpnt->sense_buffer[0] & 0x7f) == 0x70) { /* Sense current */
277 		switch (SCpnt->sense_buffer[2]) {
278 		case MEDIUM_ERROR:
279 		case VOLUME_OVERFLOW:
280 		case ILLEGAL_REQUEST:
281 			if (!(SCpnt->sense_buffer[0] & 0x90))
282 				break;
283 			error_sector = (SCpnt->sense_buffer[3] << 24) |
284 				(SCpnt->sense_buffer[4] << 16) |
285 				(SCpnt->sense_buffer[5] << 8) |
286 				SCpnt->sense_buffer[6];
287 			if (SCpnt->request->bio != NULL)
288 				block_sectors =
289 					bio_sectors(SCpnt->request->bio);
290 			if (block_sectors < 4)
291 				block_sectors = 4;
292 			if (cd->device->sector_size == 2048)
293 				error_sector <<= 2;
294 			error_sector &= ~(block_sectors - 1);
295 			good_bytes = (error_sector - SCpnt->request->sector) << 9;
296 			if (good_bytes < 0 || good_bytes >= this_count)
297 				good_bytes = 0;
298 			/*
299 			 * The SCSI specification allows for the value
300 			 * returned by READ CAPACITY to be up to 75 2K
301 			 * sectors past the last readable block.
302 			 * Therefore, if we hit a medium error within the
303 			 * last 75 2K sectors, we decrease the saved size
304 			 * value.
305 			 */
306 			if (error_sector < get_capacity(cd->disk) &&
307 			    cd->capacity - error_sector < 4 * 75)
308 				set_capacity(cd->disk, error_sector);
309 			break;
310 
311 		case RECOVERED_ERROR:
312 			good_bytes = this_count;
313 			break;
314 
315 		default:
316 			break;
317 		}
318 	}
319 
320 	return good_bytes;
321 }
322 
323 static int sr_prep_fn(struct request_queue *q, struct request *rq)
324 {
325 	int block = 0, this_count, s_size;
326 	struct scsi_cd *cd;
327 	struct scsi_cmnd *SCpnt;
328 	struct scsi_device *sdp = q->queuedata;
329 	int ret;
330 
331 	if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
332 		ret = scsi_setup_blk_pc_cmnd(sdp, rq);
333 		goto out;
334 	} else if (rq->cmd_type != REQ_TYPE_FS) {
335 		ret = BLKPREP_KILL;
336 		goto out;
337 	}
338 	ret = scsi_setup_fs_cmnd(sdp, rq);
339 	if (ret != BLKPREP_OK)
340 		goto out;
341 	SCpnt = rq->special;
342 	cd = scsi_cd(rq->rq_disk);
343 
344 	/* from here on until we're complete, any goto out
345 	 * is used for a killable error condition */
346 	ret = BLKPREP_KILL;
347 
348 	SCSI_LOG_HLQUEUE(1, printk("Doing sr request, dev = %s, block = %d\n",
349 				cd->disk->disk_name, block));
350 
351 	if (!cd->device || !scsi_device_online(cd->device)) {
352 		SCSI_LOG_HLQUEUE(2, printk("Finishing %ld sectors\n",
353 					rq->nr_sectors));
354 		SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
355 		goto out;
356 	}
357 
358 	if (cd->device->changed) {
359 		/*
360 		 * quietly refuse to do anything to a changed disc until the
361 		 * changed bit has been reset
362 		 */
363 		goto out;
364 	}
365 
366 	/*
367 	 * we do lazy blocksize switching (when reading XA sectors,
368 	 * see CDROMREADMODE2 ioctl)
369 	 */
370 	s_size = cd->device->sector_size;
371 	if (s_size > 2048) {
372 		if (!in_interrupt())
373 			sr_set_blocklength(cd, 2048);
374 		else
375 			printk("sr: can't switch blocksize: in interrupt\n");
376 	}
377 
378 	if (s_size != 512 && s_size != 1024 && s_size != 2048) {
379 		scmd_printk(KERN_ERR, SCpnt, "bad sector size %d\n", s_size);
380 		goto out;
381 	}
382 
383 	if (rq_data_dir(rq) == WRITE) {
384 		if (!cd->device->writeable)
385 			goto out;
386 		SCpnt->cmnd[0] = WRITE_10;
387 		SCpnt->sc_data_direction = DMA_TO_DEVICE;
388  	 	cd->cdi.media_written = 1;
389 	} else if (rq_data_dir(rq) == READ) {
390 		SCpnt->cmnd[0] = READ_10;
391 		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
392 	} else {
393 		blk_dump_rq_flags(rq, "Unknown sr command");
394 		goto out;
395 	}
396 
397 	{
398 		struct scatterlist *sg;
399 		int i, size = 0, sg_count = scsi_sg_count(SCpnt);
400 
401 		scsi_for_each_sg(SCpnt, sg, sg_count, i)
402 			size += sg->length;
403 
404 		if (size != scsi_bufflen(SCpnt)) {
405 			scmd_printk(KERN_ERR, SCpnt,
406 				"mismatch count %d, bytes %d\n",
407 				size, scsi_bufflen(SCpnt));
408 			if (scsi_bufflen(SCpnt) > size)
409 				SCpnt->sdb.length = size;
410 		}
411 	}
412 
413 	/*
414 	 * request doesn't start on hw block boundary, add scatter pads
415 	 */
416 	if (((unsigned int)rq->sector % (s_size >> 9)) ||
417 	    (scsi_bufflen(SCpnt) % s_size)) {
418 		scmd_printk(KERN_NOTICE, SCpnt, "unaligned transfer\n");
419 		goto out;
420 	}
421 
422 	this_count = (scsi_bufflen(SCpnt) >> 9) / (s_size >> 9);
423 
424 
425 	SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n",
426 				cd->cdi.name,
427 				(rq_data_dir(rq) == WRITE) ?
428 					"writing" : "reading",
429 				this_count, rq->nr_sectors));
430 
431 	SCpnt->cmnd[1] = 0;
432 	block = (unsigned int)rq->sector / (s_size >> 9);
433 
434 	if (this_count > 0xffff) {
435 		this_count = 0xffff;
436 		SCpnt->sdb.length = this_count * s_size;
437 	}
438 
439 	SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
440 	SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
441 	SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
442 	SCpnt->cmnd[5] = (unsigned char) block & 0xff;
443 	SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
444 	SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
445 	SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
446 
447 	/*
448 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
449 	 * host adapter, it's safe to assume that we can at least transfer
450 	 * this many bytes between each connect / disconnect.
451 	 */
452 	SCpnt->transfersize = cd->device->sector_size;
453 	SCpnt->underflow = this_count << 9;
454 	SCpnt->allowed = MAX_RETRIES;
455 
456 	/*
457 	 * This indicates that the command is ready from our end to be
458 	 * queued.
459 	 */
460 	ret = BLKPREP_OK;
461  out:
462 	return scsi_prep_return(q, rq, ret);
463 }
464 
465 static int sr_block_open(struct block_device *bdev, fmode_t mode)
466 {
467 	struct scsi_cd *cd = scsi_cd_get(bdev->bd_disk);
468 	int ret = -ENXIO;
469 
470 	if (cd) {
471 		ret = cdrom_open(&cd->cdi, bdev, mode);
472 		if (ret)
473 			scsi_cd_put(cd);
474 	}
475 	return ret;
476 }
477 
478 static int sr_block_release(struct gendisk *disk, fmode_t mode)
479 {
480 	struct scsi_cd *cd = scsi_cd(disk);
481 	cdrom_release(&cd->cdi, mode);
482 	scsi_cd_put(cd);
483 	return 0;
484 }
485 
486 static int sr_block_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
487 			  unsigned long arg)
488 {
489 	struct scsi_cd *cd = scsi_cd(bdev->bd_disk);
490 	struct scsi_device *sdev = cd->device;
491 	void __user *argp = (void __user *)arg;
492 	int ret;
493 
494 	/*
495 	 * Send SCSI addressing ioctls directly to mid level, send other
496 	 * ioctls to cdrom/block level.
497 	 */
498 	switch (cmd) {
499 	case SCSI_IOCTL_GET_IDLUN:
500 	case SCSI_IOCTL_GET_BUS_NUMBER:
501 		return scsi_ioctl(sdev, cmd, argp);
502 	}
503 
504 	ret = cdrom_ioctl(&cd->cdi, bdev, mode, cmd, arg);
505 	if (ret != -ENOSYS)
506 		return ret;
507 
508 	/*
509 	 * ENODEV means that we didn't recognise the ioctl, or that we
510 	 * cannot execute it in the current device state.  In either
511 	 * case fall through to scsi_ioctl, which will return ENDOEV again
512 	 * if it doesn't recognise the ioctl
513 	 */
514 	ret = scsi_nonblockable_ioctl(sdev, cmd, argp,
515 					(mode & FMODE_NDELAY) != 0);
516 	if (ret != -ENODEV)
517 		return ret;
518 	return scsi_ioctl(sdev, cmd, argp);
519 }
520 
521 static int sr_block_media_changed(struct gendisk *disk)
522 {
523 	struct scsi_cd *cd = scsi_cd(disk);
524 	return cdrom_media_changed(&cd->cdi);
525 }
526 
527 static struct block_device_operations sr_bdops =
528 {
529 	.owner		= THIS_MODULE,
530 	.open		= sr_block_open,
531 	.release	= sr_block_release,
532 	.locked_ioctl	= sr_block_ioctl,
533 	.media_changed	= sr_block_media_changed,
534 	/*
535 	 * No compat_ioctl for now because sr_block_ioctl never
536 	 * seems to pass arbitary ioctls down to host drivers.
537 	 */
538 };
539 
540 static int sr_open(struct cdrom_device_info *cdi, int purpose)
541 {
542 	struct scsi_cd *cd = cdi->handle;
543 	struct scsi_device *sdev = cd->device;
544 	int retval;
545 
546 	/*
547 	 * If the device is in error recovery, wait until it is done.
548 	 * If the device is offline, then disallow any access to it.
549 	 */
550 	retval = -ENXIO;
551 	if (!scsi_block_when_processing_errors(sdev))
552 		goto error_out;
553 
554 	return 0;
555 
556 error_out:
557 	return retval;
558 }
559 
560 static void sr_release(struct cdrom_device_info *cdi)
561 {
562 	struct scsi_cd *cd = cdi->handle;
563 
564 	if (cd->device->sector_size > 2048)
565 		sr_set_blocklength(cd, 2048);
566 
567 }
568 
569 static int sr_probe(struct device *dev)
570 {
571 	struct scsi_device *sdev = to_scsi_device(dev);
572 	struct gendisk *disk;
573 	struct scsi_cd *cd;
574 	int minor, error;
575 
576 	error = -ENODEV;
577 	if (sdev->type != TYPE_ROM && sdev->type != TYPE_WORM)
578 		goto fail;
579 
580 	error = -ENOMEM;
581 	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
582 	if (!cd)
583 		goto fail;
584 
585 	kref_init(&cd->kref);
586 
587 	disk = alloc_disk(1);
588 	if (!disk)
589 		goto fail_free;
590 
591 	spin_lock(&sr_index_lock);
592 	minor = find_first_zero_bit(sr_index_bits, SR_DISKS);
593 	if (minor == SR_DISKS) {
594 		spin_unlock(&sr_index_lock);
595 		error = -EBUSY;
596 		goto fail_put;
597 	}
598 	__set_bit(minor, sr_index_bits);
599 	spin_unlock(&sr_index_lock);
600 
601 	disk->major = SCSI_CDROM_MAJOR;
602 	disk->first_minor = minor;
603 	sprintf(disk->disk_name, "sr%d", minor);
604 	disk->fops = &sr_bdops;
605 	disk->flags = GENHD_FL_CD;
606 
607 	blk_queue_rq_timeout(sdev->request_queue, SR_TIMEOUT);
608 
609 	cd->device = sdev;
610 	cd->disk = disk;
611 	cd->driver = &sr_template;
612 	cd->disk = disk;
613 	cd->capacity = 0x1fffff;
614 	cd->device->changed = 1;	/* force recheck CD type */
615 	cd->previous_state = 1;
616 	cd->use = 1;
617 	cd->readcd_known = 0;
618 	cd->readcd_cdda = 0;
619 
620 	cd->cdi.ops = &sr_dops;
621 	cd->cdi.handle = cd;
622 	cd->cdi.mask = 0;
623 	cd->cdi.capacity = 1;
624 	sprintf(cd->cdi.name, "sr%d", minor);
625 
626 	sdev->sector_size = 2048;	/* A guess, just in case */
627 
628 	/* FIXME: need to handle a get_capabilities failure properly ?? */
629 	get_capabilities(cd);
630 	blk_queue_prep_rq(sdev->request_queue, sr_prep_fn);
631 	sr_vendor_init(cd);
632 
633 	disk->driverfs_dev = &sdev->sdev_gendev;
634 	set_capacity(disk, cd->capacity);
635 	disk->private_data = &cd->driver;
636 	disk->queue = sdev->request_queue;
637 	cd->cdi.disk = disk;
638 
639 	if (register_cdrom(&cd->cdi))
640 		goto fail_put;
641 
642 	dev_set_drvdata(dev, cd);
643 	disk->flags |= GENHD_FL_REMOVABLE;
644 	add_disk(disk);
645 
646 	sdev_printk(KERN_DEBUG, sdev,
647 		    "Attached scsi CD-ROM %s\n", cd->cdi.name);
648 	return 0;
649 
650 fail_put:
651 	put_disk(disk);
652 fail_free:
653 	kfree(cd);
654 fail:
655 	return error;
656 }
657 
658 
659 static void get_sectorsize(struct scsi_cd *cd)
660 {
661 	unsigned char cmd[10];
662 	unsigned char buffer[8];
663 	int the_result, retries = 3;
664 	int sector_size;
665 	struct request_queue *queue;
666 
667 	do {
668 		cmd[0] = READ_CAPACITY;
669 		memset((void *) &cmd[1], 0, 9);
670 		memset(buffer, 0, sizeof(buffer));
671 
672 		/* Do the command and wait.. */
673 		the_result = scsi_execute_req(cd->device, cmd, DMA_FROM_DEVICE,
674 					      buffer, sizeof(buffer), NULL,
675 					      SR_TIMEOUT, MAX_RETRIES, NULL);
676 
677 		retries--;
678 
679 	} while (the_result && retries);
680 
681 
682 	if (the_result) {
683 		cd->capacity = 0x1fffff;
684 		sector_size = 2048;	/* A guess, just in case */
685 	} else {
686 #if 0
687 		if (cdrom_get_last_written(&cd->cdi,
688 					   &cd->capacity))
689 #endif
690 			cd->capacity = 1 + ((buffer[0] << 24) |
691 						    (buffer[1] << 16) |
692 						    (buffer[2] << 8) |
693 						    buffer[3]);
694 		sector_size = (buffer[4] << 24) |
695 		    (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
696 		switch (sector_size) {
697 			/*
698 			 * HP 4020i CD-Recorder reports 2340 byte sectors
699 			 * Philips CD-Writers report 2352 byte sectors
700 			 *
701 			 * Use 2k sectors for them..
702 			 */
703 		case 0:
704 		case 2340:
705 		case 2352:
706 			sector_size = 2048;
707 			/* fall through */
708 		case 2048:
709 			cd->capacity *= 4;
710 			/* fall through */
711 		case 512:
712 			break;
713 		default:
714 			printk("%s: unsupported sector size %d.\n",
715 			       cd->cdi.name, sector_size);
716 			cd->capacity = 0;
717 		}
718 
719 		cd->device->sector_size = sector_size;
720 
721 		/*
722 		 * Add this so that we have the ability to correctly gauge
723 		 * what the device is capable of.
724 		 */
725 		set_capacity(cd->disk, cd->capacity);
726 	}
727 
728 	queue = cd->device->request_queue;
729 	blk_queue_hardsect_size(queue, sector_size);
730 
731 	return;
732 }
733 
734 static void get_capabilities(struct scsi_cd *cd)
735 {
736 	unsigned char *buffer;
737 	struct scsi_mode_data data;
738 	struct scsi_sense_hdr sshdr;
739 	int rc, n;
740 
741 	static const char *loadmech[] =
742 	{
743 		"caddy",
744 		"tray",
745 		"pop-up",
746 		"",
747 		"changer",
748 		"cartridge changer",
749 		"",
750 		""
751 	};
752 
753 
754 	/* allocate transfer buffer */
755 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
756 	if (!buffer) {
757 		printk(KERN_ERR "sr: out of memory.\n");
758 		return;
759 	}
760 
761 	/* eat unit attentions */
762 	sr_test_unit_ready(cd->device, &sshdr);
763 
764 	/* ask for mode page 0x2a */
765 	rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128,
766 			     SR_TIMEOUT, 3, &data, NULL);
767 
768 	if (!scsi_status_is_good(rc)) {
769 		/* failed, drive doesn't have capabilities mode page */
770 		cd->cdi.speed = 1;
771 		cd->cdi.mask |= (CDC_CD_R | CDC_CD_RW | CDC_DVD_R |
772 				 CDC_DVD | CDC_DVD_RAM |
773 				 CDC_SELECT_DISC | CDC_SELECT_SPEED |
774 				 CDC_MRW | CDC_MRW_W | CDC_RAM);
775 		kfree(buffer);
776 		printk("%s: scsi-1 drive\n", cd->cdi.name);
777 		return;
778 	}
779 
780 	n = data.header_length + data.block_descriptor_length;
781 	cd->cdi.speed = ((buffer[n + 8] << 8) + buffer[n + 9]) / 176;
782 	cd->readcd_known = 1;
783 	cd->readcd_cdda = buffer[n + 5] & 0x01;
784 	/* print some capability bits */
785 	printk("%s: scsi3-mmc drive: %dx/%dx %s%s%s%s%s%s\n", cd->cdi.name,
786 	       ((buffer[n + 14] << 8) + buffer[n + 15]) / 176,
787 	       cd->cdi.speed,
788 	       buffer[n + 3] & 0x01 ? "writer " : "", /* CD Writer */
789 	       buffer[n + 3] & 0x20 ? "dvd-ram " : "",
790 	       buffer[n + 2] & 0x02 ? "cd/rw " : "", /* can read rewriteable */
791 	       buffer[n + 4] & 0x20 ? "xa/form2 " : "",	/* can read xa/from2 */
792 	       buffer[n + 5] & 0x01 ? "cdda " : "", /* can read audio data */
793 	       loadmech[buffer[n + 6] >> 5]);
794 	if ((buffer[n + 6] >> 5) == 0)
795 		/* caddy drives can't close tray... */
796 		cd->cdi.mask |= CDC_CLOSE_TRAY;
797 	if ((buffer[n + 2] & 0x8) == 0)
798 		/* not a DVD drive */
799 		cd->cdi.mask |= CDC_DVD;
800 	if ((buffer[n + 3] & 0x20) == 0)
801 		/* can't write DVD-RAM media */
802 		cd->cdi.mask |= CDC_DVD_RAM;
803 	if ((buffer[n + 3] & 0x10) == 0)
804 		/* can't write DVD-R media */
805 		cd->cdi.mask |= CDC_DVD_R;
806 	if ((buffer[n + 3] & 0x2) == 0)
807 		/* can't write CD-RW media */
808 		cd->cdi.mask |= CDC_CD_RW;
809 	if ((buffer[n + 3] & 0x1) == 0)
810 		/* can't write CD-R media */
811 		cd->cdi.mask |= CDC_CD_R;
812 	if ((buffer[n + 6] & 0x8) == 0)
813 		/* can't eject */
814 		cd->cdi.mask |= CDC_OPEN_TRAY;
815 
816 	if ((buffer[n + 6] >> 5) == mechtype_individual_changer ||
817 	    (buffer[n + 6] >> 5) == mechtype_cartridge_changer)
818 		cd->cdi.capacity =
819 		    cdrom_number_of_slots(&cd->cdi);
820 	if (cd->cdi.capacity <= 1)
821 		/* not a changer */
822 		cd->cdi.mask |= CDC_SELECT_DISC;
823 	/*else    I don't think it can close its tray
824 		cd->cdi.mask |= CDC_CLOSE_TRAY; */
825 
826 	/*
827 	 * if DVD-RAM, MRW-W or CD-RW, we are randomly writable
828 	 */
829 	if ((cd->cdi.mask & (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) !=
830 			(CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) {
831 		cd->device->writeable = 1;
832 	}
833 
834 	kfree(buffer);
835 }
836 
837 /*
838  * sr_packet() is the entry point for the generic commands generated
839  * by the Uniform CD-ROM layer.
840  */
841 static int sr_packet(struct cdrom_device_info *cdi,
842 		struct packet_command *cgc)
843 {
844 	if (cgc->timeout <= 0)
845 		cgc->timeout = IOCTL_TIMEOUT;
846 
847 	sr_do_ioctl(cdi->handle, cgc);
848 
849 	return cgc->stat;
850 }
851 
852 /**
853  *	sr_kref_release - Called to free the scsi_cd structure
854  *	@kref: pointer to embedded kref
855  *
856  *	sr_ref_mutex must be held entering this routine.  Because it is
857  *	called on last put, you should always use the scsi_cd_get()
858  *	scsi_cd_put() helpers which manipulate the semaphore directly
859  *	and never do a direct kref_put().
860  **/
861 static void sr_kref_release(struct kref *kref)
862 {
863 	struct scsi_cd *cd = container_of(kref, struct scsi_cd, kref);
864 	struct gendisk *disk = cd->disk;
865 
866 	spin_lock(&sr_index_lock);
867 	clear_bit(MINOR(disk_devt(disk)), sr_index_bits);
868 	spin_unlock(&sr_index_lock);
869 
870 	unregister_cdrom(&cd->cdi);
871 
872 	disk->private_data = NULL;
873 
874 	put_disk(disk);
875 
876 	kfree(cd);
877 }
878 
879 static int sr_remove(struct device *dev)
880 {
881 	struct scsi_cd *cd = dev_get_drvdata(dev);
882 
883 	del_gendisk(cd->disk);
884 
885 	mutex_lock(&sr_ref_mutex);
886 	kref_put(&cd->kref, sr_kref_release);
887 	mutex_unlock(&sr_ref_mutex);
888 
889 	return 0;
890 }
891 
892 static int __init init_sr(void)
893 {
894 	int rc;
895 
896 	rc = register_blkdev(SCSI_CDROM_MAJOR, "sr");
897 	if (rc)
898 		return rc;
899 	rc = scsi_register_driver(&sr_template.gendrv);
900 	if (rc)
901 		unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
902 
903 	return rc;
904 }
905 
906 static void __exit exit_sr(void)
907 {
908 	scsi_unregister_driver(&sr_template.gendrv);
909 	unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
910 }
911 
912 module_init(init_sr);
913 module_exit(exit_sr);
914 MODULE_LICENSE("GPL");
915