xref: /openbmc/linux/drivers/scsi/sr.c (revision 3a598264)
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 <linux/slab.h>
48 #include <asm/uaccess.h>
49 
50 #include <scsi/scsi.h>
51 #include <scsi/scsi_dbg.h>
52 #include <scsi/scsi_device.h>
53 #include <scsi/scsi_driver.h>
54 #include <scsi/scsi_cmnd.h>
55 #include <scsi/scsi_eh.h>
56 #include <scsi/scsi_host.h>
57 #include <scsi/scsi_ioctl.h>	/* For the door lock/unlock commands */
58 
59 #include "scsi_logging.h"
60 #include "sr.h"
61 
62 
63 MODULE_DESCRIPTION("SCSI cdrom (sr) driver");
64 MODULE_LICENSE("GPL");
65 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_CDROM_MAJOR);
66 MODULE_ALIAS_SCSI_DEVICE(TYPE_ROM);
67 MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);
68 
69 #define SR_DISKS	256
70 
71 #define SR_CAPABILITIES \
72 	(CDC_CLOSE_TRAY|CDC_OPEN_TRAY|CDC_LOCK|CDC_SELECT_SPEED| \
73 	 CDC_SELECT_DISC|CDC_MULTI_SESSION|CDC_MCN|CDC_MEDIA_CHANGED| \
74 	 CDC_PLAY_AUDIO|CDC_RESET|CDC_DRIVE_STATUS| \
75 	 CDC_CD_R|CDC_CD_RW|CDC_DVD|CDC_DVD_R|CDC_DVD_RAM|CDC_GENERIC_PACKET| \
76 	 CDC_MRW|CDC_MRW_W|CDC_RAM)
77 
78 static int sr_probe(struct device *);
79 static int sr_remove(struct device *);
80 static int sr_done(struct scsi_cmnd *);
81 
82 static struct scsi_driver sr_template = {
83 	.owner			= THIS_MODULE,
84 	.gendrv = {
85 		.name   	= "sr",
86 		.probe		= sr_probe,
87 		.remove		= sr_remove,
88 	},
89 	.done			= sr_done,
90 };
91 
92 static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
93 static DEFINE_SPINLOCK(sr_index_lock);
94 
95 /* This semaphore is used to mediate the 0->1 reference get in the
96  * face of object destruction (i.e. we can't allow a get on an
97  * object after last put) */
98 static DEFINE_MUTEX(sr_ref_mutex);
99 
100 static int sr_open(struct cdrom_device_info *, int);
101 static void sr_release(struct cdrom_device_info *);
102 
103 static void get_sectorsize(struct scsi_cd *);
104 static void get_capabilities(struct scsi_cd *);
105 
106 static int sr_media_change(struct cdrom_device_info *, int);
107 static int sr_packet(struct cdrom_device_info *, struct packet_command *);
108 
109 static struct cdrom_device_ops sr_dops = {
110 	.open			= sr_open,
111 	.release	 	= sr_release,
112 	.drive_status	 	= sr_drive_status,
113 	.media_changed		= sr_media_change,
114 	.tray_move		= sr_tray_move,
115 	.lock_door		= sr_lock_door,
116 	.select_speed		= sr_select_speed,
117 	.get_last_session	= sr_get_last_session,
118 	.get_mcn		= sr_get_mcn,
119 	.reset			= sr_reset,
120 	.audio_ioctl		= sr_audio_ioctl,
121 	.capability		= SR_CAPABILITIES,
122 	.generic_packet		= sr_packet,
123 };
124 
125 static void sr_kref_release(struct kref *kref);
126 
127 static inline struct scsi_cd *scsi_cd(struct gendisk *disk)
128 {
129 	return container_of(disk->private_data, struct scsi_cd, driver);
130 }
131 
132 /*
133  * The get and put routines for the struct scsi_cd.  Note this entity
134  * has a scsi_device pointer and owns a reference to this.
135  */
136 static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk)
137 {
138 	struct scsi_cd *cd = NULL;
139 
140 	mutex_lock(&sr_ref_mutex);
141 	if (disk->private_data == NULL)
142 		goto out;
143 	cd = scsi_cd(disk);
144 	kref_get(&cd->kref);
145 	if (scsi_device_get(cd->device))
146 		goto out_put;
147 	goto out;
148 
149  out_put:
150 	kref_put(&cd->kref, sr_kref_release);
151 	cd = NULL;
152  out:
153 	mutex_unlock(&sr_ref_mutex);
154 	return cd;
155 }
156 
157 static void scsi_cd_put(struct scsi_cd *cd)
158 {
159 	struct scsi_device *sdev = cd->device;
160 
161 	mutex_lock(&sr_ref_mutex);
162 	kref_put(&cd->kref, sr_kref_release);
163 	scsi_device_put(sdev);
164 	mutex_unlock(&sr_ref_mutex);
165 }
166 
167 /* identical to scsi_test_unit_ready except that it doesn't
168  * eat the NOT_READY returns for removable media */
169 int sr_test_unit_ready(struct scsi_device *sdev, struct scsi_sense_hdr *sshdr)
170 {
171 	int retries = MAX_RETRIES;
172 	int the_result;
173 	u8 cmd[] = {TEST_UNIT_READY, 0, 0, 0, 0, 0 };
174 
175 	/* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
176 	 * conditions are gone, or a timeout happens
177 	 */
178 	do {
179 		the_result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL,
180 					      0, sshdr, SR_TIMEOUT,
181 					      retries--, NULL);
182 		if (scsi_sense_valid(sshdr) &&
183 		    sshdr->sense_key == UNIT_ATTENTION)
184 			sdev->changed = 1;
185 
186 	} while (retries > 0 &&
187 		 (!scsi_status_is_good(the_result) ||
188 		  (scsi_sense_valid(sshdr) &&
189 		   sshdr->sense_key == UNIT_ATTENTION)));
190 	return the_result;
191 }
192 
193 /*
194  * This function checks to see if the media has been changed in the
195  * CDROM drive.  It is possible that we have already sensed a change,
196  * or the drive may have sensed one and not yet reported it.  We must
197  * be ready for either case. This function always reports the current
198  * value of the changed bit.  If flag is 0, then the changed bit is reset.
199  * This function could be done as an ioctl, but we would need to have
200  * an inode for that to work, and we do not always have one.
201  */
202 
203 static int sr_media_change(struct cdrom_device_info *cdi, int slot)
204 {
205 	struct scsi_cd *cd = cdi->handle;
206 	int retval;
207 	struct scsi_sense_hdr *sshdr;
208 
209 	if (CDSL_CURRENT != slot) {
210 		/* no changer support */
211 		return -EINVAL;
212 	}
213 
214 	sshdr =  kzalloc(sizeof(*sshdr), GFP_KERNEL);
215 	retval = sr_test_unit_ready(cd->device, sshdr);
216 	if (retval || (scsi_sense_valid(sshdr) &&
217 		       /* 0x3a is medium not present */
218 		       sshdr->asc == 0x3a)) {
219 		/* Media not present or unable to test, unit probably not
220 		 * ready. This usually means there is no disc in the drive.
221 		 * Mark as changed, and we will figure it out later once
222 		 * the drive is available again.
223 		 */
224 		cd->device->changed = 1;
225 		/* This will force a flush, if called from check_disk_change */
226 		retval = 1;
227 		goto out;
228 	};
229 
230 	retval = cd->device->changed;
231 	cd->device->changed = 0;
232 	/* If the disk changed, the capacity will now be different,
233 	 * so we force a re-read of this information */
234 	if (retval) {
235 		/* check multisession offset etc */
236 		sr_cd_check(cdi);
237 		get_sectorsize(cd);
238 	}
239 
240 out:
241 	/* Notify userspace, that media has changed. */
242 	if (retval != cd->previous_state)
243 		sdev_evt_send_simple(cd->device, SDEV_EVT_MEDIA_CHANGE,
244 				     GFP_KERNEL);
245 	cd->previous_state = retval;
246 	kfree(sshdr);
247 
248 	return retval;
249 }
250 
251 /*
252  * sr_done is the interrupt routine for the device driver.
253  *
254  * It will be notified on the end of a SCSI read / write, and will take one
255  * of several actions based on success or failure.
256  */
257 static int sr_done(struct scsi_cmnd *SCpnt)
258 {
259 	int result = SCpnt->result;
260 	int this_count = scsi_bufflen(SCpnt);
261 	int good_bytes = (result == 0 ? this_count : 0);
262 	int block_sectors = 0;
263 	long error_sector;
264 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
265 
266 #ifdef DEBUG
267 	printk("sr.c done: %x\n", result);
268 #endif
269 
270 	/*
271 	 * Handle MEDIUM ERRORs or VOLUME OVERFLOWs that indicate partial
272 	 * success.  Since this is a relatively rare error condition, no
273 	 * care is taken to avoid unnecessary additional work such as
274 	 * memcpy's that could be avoided.
275 	 */
276 	if (driver_byte(result) != 0 &&		/* An error occurred */
277 	    (SCpnt->sense_buffer[0] & 0x7f) == 0x70) { /* Sense current */
278 		switch (SCpnt->sense_buffer[2]) {
279 		case MEDIUM_ERROR:
280 		case VOLUME_OVERFLOW:
281 		case ILLEGAL_REQUEST:
282 			if (!(SCpnt->sense_buffer[0] & 0x90))
283 				break;
284 			error_sector = (SCpnt->sense_buffer[3] << 24) |
285 				(SCpnt->sense_buffer[4] << 16) |
286 				(SCpnt->sense_buffer[5] << 8) |
287 				SCpnt->sense_buffer[6];
288 			if (SCpnt->request->bio != NULL)
289 				block_sectors =
290 					bio_sectors(SCpnt->request->bio);
291 			if (block_sectors < 4)
292 				block_sectors = 4;
293 			if (cd->device->sector_size == 2048)
294 				error_sector <<= 2;
295 			error_sector &= ~(block_sectors - 1);
296 			good_bytes = (error_sector -
297 				      blk_rq_pos(SCpnt->request)) << 9;
298 			if (good_bytes < 0 || good_bytes >= this_count)
299 				good_bytes = 0;
300 			/*
301 			 * The SCSI specification allows for the value
302 			 * returned by READ CAPACITY to be up to 75 2K
303 			 * sectors past the last readable block.
304 			 * Therefore, if we hit a medium error within the
305 			 * last 75 2K sectors, we decrease the saved size
306 			 * value.
307 			 */
308 			if (error_sector < get_capacity(cd->disk) &&
309 			    cd->capacity - error_sector < 4 * 75)
310 				set_capacity(cd->disk, error_sector);
311 			break;
312 
313 		case RECOVERED_ERROR:
314 			good_bytes = this_count;
315 			break;
316 
317 		default:
318 			break;
319 		}
320 	}
321 
322 	return good_bytes;
323 }
324 
325 static int sr_prep_fn(struct request_queue *q, struct request *rq)
326 {
327 	int block = 0, this_count, s_size;
328 	struct scsi_cd *cd;
329 	struct scsi_cmnd *SCpnt;
330 	struct scsi_device *sdp = q->queuedata;
331 	int ret;
332 
333 	if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
334 		ret = scsi_setup_blk_pc_cmnd(sdp, rq);
335 		goto out;
336 	} else if (rq->cmd_type != REQ_TYPE_FS) {
337 		ret = BLKPREP_KILL;
338 		goto out;
339 	}
340 	ret = scsi_setup_fs_cmnd(sdp, rq);
341 	if (ret != BLKPREP_OK)
342 		goto out;
343 	SCpnt = rq->special;
344 	cd = scsi_cd(rq->rq_disk);
345 
346 	/* from here on until we're complete, any goto out
347 	 * is used for a killable error condition */
348 	ret = BLKPREP_KILL;
349 
350 	SCSI_LOG_HLQUEUE(1, printk("Doing sr request, dev = %s, block = %d\n",
351 				cd->disk->disk_name, block));
352 
353 	if (!cd->device || !scsi_device_online(cd->device)) {
354 		SCSI_LOG_HLQUEUE(2, printk("Finishing %u sectors\n",
355 					   blk_rq_sectors(rq)));
356 		SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
357 		goto out;
358 	}
359 
360 	if (cd->device->changed) {
361 		/*
362 		 * quietly refuse to do anything to a changed disc until the
363 		 * changed bit has been reset
364 		 */
365 		goto out;
366 	}
367 
368 	/*
369 	 * we do lazy blocksize switching (when reading XA sectors,
370 	 * see CDROMREADMODE2 ioctl)
371 	 */
372 	s_size = cd->device->sector_size;
373 	if (s_size > 2048) {
374 		if (!in_interrupt())
375 			sr_set_blocklength(cd, 2048);
376 		else
377 			printk("sr: can't switch blocksize: in interrupt\n");
378 	}
379 
380 	if (s_size != 512 && s_size != 1024 && s_size != 2048) {
381 		scmd_printk(KERN_ERR, SCpnt, "bad sector size %d\n", s_size);
382 		goto out;
383 	}
384 
385 	if (rq_data_dir(rq) == WRITE) {
386 		if (!cd->device->writeable)
387 			goto out;
388 		SCpnt->cmnd[0] = WRITE_10;
389 		SCpnt->sc_data_direction = DMA_TO_DEVICE;
390  	 	cd->cdi.media_written = 1;
391 	} else if (rq_data_dir(rq) == READ) {
392 		SCpnt->cmnd[0] = READ_10;
393 		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
394 	} else {
395 		blk_dump_rq_flags(rq, "Unknown sr command");
396 		goto out;
397 	}
398 
399 	{
400 		struct scatterlist *sg;
401 		int i, size = 0, sg_count = scsi_sg_count(SCpnt);
402 
403 		scsi_for_each_sg(SCpnt, sg, sg_count, i)
404 			size += sg->length;
405 
406 		if (size != scsi_bufflen(SCpnt)) {
407 			scmd_printk(KERN_ERR, SCpnt,
408 				"mismatch count %d, bytes %d\n",
409 				size, scsi_bufflen(SCpnt));
410 			if (scsi_bufflen(SCpnt) > size)
411 				SCpnt->sdb.length = size;
412 		}
413 	}
414 
415 	/*
416 	 * request doesn't start on hw block boundary, add scatter pads
417 	 */
418 	if (((unsigned int)blk_rq_pos(rq) % (s_size >> 9)) ||
419 	    (scsi_bufflen(SCpnt) % s_size)) {
420 		scmd_printk(KERN_NOTICE, SCpnt, "unaligned transfer\n");
421 		goto out;
422 	}
423 
424 	this_count = (scsi_bufflen(SCpnt) >> 9) / (s_size >> 9);
425 
426 
427 	SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%u 512 byte blocks.\n",
428 				cd->cdi.name,
429 				(rq_data_dir(rq) == WRITE) ?
430 					"writing" : "reading",
431 				this_count, blk_rq_sectors(rq)));
432 
433 	SCpnt->cmnd[1] = 0;
434 	block = (unsigned int)blk_rq_pos(rq) / (s_size >> 9);
435 
436 	if (this_count > 0xffff) {
437 		this_count = 0xffff;
438 		SCpnt->sdb.length = this_count * s_size;
439 	}
440 
441 	SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
442 	SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
443 	SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
444 	SCpnt->cmnd[5] = (unsigned char) block & 0xff;
445 	SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
446 	SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
447 	SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
448 
449 	/*
450 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
451 	 * host adapter, it's safe to assume that we can at least transfer
452 	 * this many bytes between each connect / disconnect.
453 	 */
454 	SCpnt->transfersize = cd->device->sector_size;
455 	SCpnt->underflow = this_count << 9;
456 	SCpnt->allowed = MAX_RETRIES;
457 
458 	/*
459 	 * This indicates that the command is ready from our end to be
460 	 * queued.
461 	 */
462 	ret = BLKPREP_OK;
463  out:
464 	return scsi_prep_return(q, rq, ret);
465 }
466 
467 static int sr_block_open(struct block_device *bdev, fmode_t mode)
468 {
469 	struct scsi_cd *cd = scsi_cd_get(bdev->bd_disk);
470 	int ret = -ENXIO;
471 
472 	if (cd) {
473 		ret = cdrom_open(&cd->cdi, bdev, mode);
474 		if (ret)
475 			scsi_cd_put(cd);
476 	}
477 	return ret;
478 }
479 
480 static int sr_block_release(struct gendisk *disk, fmode_t mode)
481 {
482 	struct scsi_cd *cd = scsi_cd(disk);
483 	cdrom_release(&cd->cdi, mode);
484 	scsi_cd_put(cd);
485 	return 0;
486 }
487 
488 static int sr_block_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
489 			  unsigned long arg)
490 {
491 	struct scsi_cd *cd = scsi_cd(bdev->bd_disk);
492 	struct scsi_device *sdev = cd->device;
493 	void __user *argp = (void __user *)arg;
494 	int ret;
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, argp);
504 	}
505 
506 	ret = cdrom_ioctl(&cd->cdi, bdev, mode, cmd, arg);
507 	if (ret != -ENOSYS)
508 		return ret;
509 
510 	/*
511 	 * ENODEV means that we didn't recognise the ioctl, or that we
512 	 * cannot execute it in the current device state.  In either
513 	 * case fall through to scsi_ioctl, which will return ENDOEV again
514 	 * if it doesn't recognise the ioctl
515 	 */
516 	ret = scsi_nonblockable_ioctl(sdev, cmd, argp,
517 					(mode & FMODE_NDELAY) != 0);
518 	if (ret != -ENODEV)
519 		return ret;
520 	return scsi_ioctl(sdev, cmd, argp);
521 }
522 
523 static int sr_block_media_changed(struct gendisk *disk)
524 {
525 	struct scsi_cd *cd = scsi_cd(disk);
526 	return cdrom_media_changed(&cd->cdi);
527 }
528 
529 static const struct block_device_operations sr_bdops =
530 {
531 	.owner		= THIS_MODULE,
532 	.open		= sr_block_open,
533 	.release	= sr_block_release,
534 	.locked_ioctl	= sr_block_ioctl,
535 	.media_changed	= sr_block_media_changed,
536 	/*
537 	 * No compat_ioctl for now because sr_block_ioctl never
538 	 * seems to pass arbitary ioctls down to host drivers.
539 	 */
540 };
541 
542 static int sr_open(struct cdrom_device_info *cdi, int purpose)
543 {
544 	struct scsi_cd *cd = cdi->handle;
545 	struct scsi_device *sdev = cd->device;
546 	int retval;
547 
548 	/*
549 	 * If the device is in error recovery, wait until it is done.
550 	 * If the device is offline, then disallow any access to it.
551 	 */
552 	retval = -ENXIO;
553 	if (!scsi_block_when_processing_errors(sdev))
554 		goto error_out;
555 
556 	return 0;
557 
558 error_out:
559 	return retval;
560 }
561 
562 static void sr_release(struct cdrom_device_info *cdi)
563 {
564 	struct scsi_cd *cd = cdi->handle;
565 
566 	if (cd->device->sector_size > 2048)
567 		sr_set_blocklength(cd, 2048);
568 
569 }
570 
571 static int sr_probe(struct device *dev)
572 {
573 	struct scsi_device *sdev = to_scsi_device(dev);
574 	struct gendisk *disk;
575 	struct scsi_cd *cd;
576 	int minor, error;
577 
578 	error = -ENODEV;
579 	if (sdev->type != TYPE_ROM && sdev->type != TYPE_WORM)
580 		goto fail;
581 
582 	error = -ENOMEM;
583 	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
584 	if (!cd)
585 		goto fail;
586 
587 	kref_init(&cd->kref);
588 
589 	disk = alloc_disk(1);
590 	if (!disk)
591 		goto fail_free;
592 
593 	spin_lock(&sr_index_lock);
594 	minor = find_first_zero_bit(sr_index_bits, SR_DISKS);
595 	if (minor == SR_DISKS) {
596 		spin_unlock(&sr_index_lock);
597 		error = -EBUSY;
598 		goto fail_put;
599 	}
600 	__set_bit(minor, sr_index_bits);
601 	spin_unlock(&sr_index_lock);
602 
603 	disk->major = SCSI_CDROM_MAJOR;
604 	disk->first_minor = minor;
605 	sprintf(disk->disk_name, "sr%d", minor);
606 	disk->fops = &sr_bdops;
607 	disk->flags = GENHD_FL_CD;
608 
609 	blk_queue_rq_timeout(sdev->request_queue, SR_TIMEOUT);
610 
611 	cd->device = sdev;
612 	cd->disk = disk;
613 	cd->driver = &sr_template;
614 	cd->disk = disk;
615 	cd->capacity = 0x1fffff;
616 	cd->device->changed = 1;	/* force recheck CD type */
617 	cd->previous_state = 1;
618 	cd->use = 1;
619 	cd->readcd_known = 0;
620 	cd->readcd_cdda = 0;
621 
622 	cd->cdi.ops = &sr_dops;
623 	cd->cdi.handle = cd;
624 	cd->cdi.mask = 0;
625 	cd->cdi.capacity = 1;
626 	sprintf(cd->cdi.name, "sr%d", minor);
627 
628 	sdev->sector_size = 2048;	/* A guess, just in case */
629 
630 	/* FIXME: need to handle a get_capabilities failure properly ?? */
631 	get_capabilities(cd);
632 	blk_queue_prep_rq(sdev->request_queue, sr_prep_fn);
633 	sr_vendor_init(cd);
634 
635 	disk->driverfs_dev = &sdev->sdev_gendev;
636 	set_capacity(disk, cd->capacity);
637 	disk->private_data = &cd->driver;
638 	disk->queue = sdev->request_queue;
639 	cd->cdi.disk = disk;
640 
641 	if (register_cdrom(&cd->cdi))
642 		goto fail_put;
643 
644 	dev_set_drvdata(dev, cd);
645 	disk->flags |= GENHD_FL_REMOVABLE;
646 	add_disk(disk);
647 
648 	sdev_printk(KERN_DEBUG, sdev,
649 		    "Attached scsi CD-ROM %s\n", cd->cdi.name);
650 	return 0;
651 
652 fail_put:
653 	put_disk(disk);
654 fail_free:
655 	kfree(cd);
656 fail:
657 	return error;
658 }
659 
660 
661 static void get_sectorsize(struct scsi_cd *cd)
662 {
663 	unsigned char cmd[10];
664 	unsigned char buffer[8];
665 	int the_result, retries = 3;
666 	int sector_size;
667 	struct request_queue *queue;
668 
669 	do {
670 		cmd[0] = READ_CAPACITY;
671 		memset((void *) &cmd[1], 0, 9);
672 		memset(buffer, 0, sizeof(buffer));
673 
674 		/* Do the command and wait.. */
675 		the_result = scsi_execute_req(cd->device, cmd, DMA_FROM_DEVICE,
676 					      buffer, sizeof(buffer), NULL,
677 					      SR_TIMEOUT, MAX_RETRIES, NULL);
678 
679 		retries--;
680 
681 	} while (the_result && retries);
682 
683 
684 	if (the_result) {
685 		cd->capacity = 0x1fffff;
686 		sector_size = 2048;	/* A guess, just in case */
687 	} else {
688 		long last_written;
689 
690 		cd->capacity = 1 + ((buffer[0] << 24) | (buffer[1] << 16) |
691 				    (buffer[2] << 8) | buffer[3]);
692 		/*
693 		 * READ_CAPACITY doesn't return the correct size on
694 		 * certain UDF media.  If last_written is larger, use
695 		 * it instead.
696 		 *
697 		 * http://bugzilla.kernel.org/show_bug.cgi?id=9668
698 		 */
699 		if (!cdrom_get_last_written(&cd->cdi, &last_written))
700 			cd->capacity = max_t(long, cd->capacity, last_written);
701 
702 		sector_size = (buffer[4] << 24) |
703 		    (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
704 		switch (sector_size) {
705 			/*
706 			 * HP 4020i CD-Recorder reports 2340 byte sectors
707 			 * Philips CD-Writers report 2352 byte sectors
708 			 *
709 			 * Use 2k sectors for them..
710 			 */
711 		case 0:
712 		case 2340:
713 		case 2352:
714 			sector_size = 2048;
715 			/* fall through */
716 		case 2048:
717 			cd->capacity *= 4;
718 			/* fall through */
719 		case 512:
720 			break;
721 		default:
722 			printk("%s: unsupported sector size %d.\n",
723 			       cd->cdi.name, sector_size);
724 			cd->capacity = 0;
725 		}
726 
727 		cd->device->sector_size = sector_size;
728 
729 		/*
730 		 * Add this so that we have the ability to correctly gauge
731 		 * what the device is capable of.
732 		 */
733 		set_capacity(cd->disk, cd->capacity);
734 	}
735 
736 	queue = cd->device->request_queue;
737 	blk_queue_logical_block_size(queue, sector_size);
738 
739 	return;
740 }
741 
742 static void get_capabilities(struct scsi_cd *cd)
743 {
744 	unsigned char *buffer;
745 	struct scsi_mode_data data;
746 	struct scsi_sense_hdr sshdr;
747 	int rc, n;
748 
749 	static const char *loadmech[] =
750 	{
751 		"caddy",
752 		"tray",
753 		"pop-up",
754 		"",
755 		"changer",
756 		"cartridge changer",
757 		"",
758 		""
759 	};
760 
761 
762 	/* allocate transfer buffer */
763 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
764 	if (!buffer) {
765 		printk(KERN_ERR "sr: out of memory.\n");
766 		return;
767 	}
768 
769 	/* eat unit attentions */
770 	sr_test_unit_ready(cd->device, &sshdr);
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 				 CDC_MRW | CDC_MRW_W | CDC_RAM);
783 		kfree(buffer);
784 		printk("%s: scsi-1 drive\n", cd->cdi.name);
785 		return;
786 	}
787 
788 	n = data.header_length + data.block_descriptor_length;
789 	cd->cdi.speed = ((buffer[n + 8] << 8) + buffer[n + 9]) / 176;
790 	cd->readcd_known = 1;
791 	cd->readcd_cdda = buffer[n + 5] & 0x01;
792 	/* print some capability bits */
793 	printk("%s: scsi3-mmc drive: %dx/%dx %s%s%s%s%s%s\n", cd->cdi.name,
794 	       ((buffer[n + 14] << 8) + buffer[n + 15]) / 176,
795 	       cd->cdi.speed,
796 	       buffer[n + 3] & 0x01 ? "writer " : "", /* CD Writer */
797 	       buffer[n + 3] & 0x20 ? "dvd-ram " : "",
798 	       buffer[n + 2] & 0x02 ? "cd/rw " : "", /* can read rewriteable */
799 	       buffer[n + 4] & 0x20 ? "xa/form2 " : "",	/* can read xa/from2 */
800 	       buffer[n + 5] & 0x01 ? "cdda " : "", /* can read audio data */
801 	       loadmech[buffer[n + 6] >> 5]);
802 	if ((buffer[n + 6] >> 5) == 0)
803 		/* caddy drives can't close tray... */
804 		cd->cdi.mask |= CDC_CLOSE_TRAY;
805 	if ((buffer[n + 2] & 0x8) == 0)
806 		/* not a DVD drive */
807 		cd->cdi.mask |= CDC_DVD;
808 	if ((buffer[n + 3] & 0x20) == 0)
809 		/* can't write DVD-RAM media */
810 		cd->cdi.mask |= CDC_DVD_RAM;
811 	if ((buffer[n + 3] & 0x10) == 0)
812 		/* can't write DVD-R media */
813 		cd->cdi.mask |= CDC_DVD_R;
814 	if ((buffer[n + 3] & 0x2) == 0)
815 		/* can't write CD-RW media */
816 		cd->cdi.mask |= CDC_CD_RW;
817 	if ((buffer[n + 3] & 0x1) == 0)
818 		/* can't write CD-R media */
819 		cd->cdi.mask |= CDC_CD_R;
820 	if ((buffer[n + 6] & 0x8) == 0)
821 		/* can't eject */
822 		cd->cdi.mask |= CDC_OPEN_TRAY;
823 
824 	if ((buffer[n + 6] >> 5) == mechtype_individual_changer ||
825 	    (buffer[n + 6] >> 5) == mechtype_cartridge_changer)
826 		cd->cdi.capacity =
827 		    cdrom_number_of_slots(&cd->cdi);
828 	if (cd->cdi.capacity <= 1)
829 		/* not a changer */
830 		cd->cdi.mask |= CDC_SELECT_DISC;
831 	/*else    I don't think it can close its tray
832 		cd->cdi.mask |= CDC_CLOSE_TRAY; */
833 
834 	/*
835 	 * if DVD-RAM, MRW-W or CD-RW, we are randomly writable
836 	 */
837 	if ((cd->cdi.mask & (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) !=
838 			(CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) {
839 		cd->device->writeable = 1;
840 	}
841 
842 	kfree(buffer);
843 }
844 
845 /*
846  * sr_packet() is the entry point for the generic commands generated
847  * by the Uniform CD-ROM layer.
848  */
849 static int sr_packet(struct cdrom_device_info *cdi,
850 		struct packet_command *cgc)
851 {
852 	if (cgc->timeout <= 0)
853 		cgc->timeout = IOCTL_TIMEOUT;
854 
855 	sr_do_ioctl(cdi->handle, cgc);
856 
857 	return cgc->stat;
858 }
859 
860 /**
861  *	sr_kref_release - Called to free the scsi_cd structure
862  *	@kref: pointer to embedded kref
863  *
864  *	sr_ref_mutex must be held entering this routine.  Because it is
865  *	called on last put, you should always use the scsi_cd_get()
866  *	scsi_cd_put() helpers which manipulate the semaphore directly
867  *	and never do a direct kref_put().
868  **/
869 static void sr_kref_release(struct kref *kref)
870 {
871 	struct scsi_cd *cd = container_of(kref, struct scsi_cd, kref);
872 	struct gendisk *disk = cd->disk;
873 
874 	spin_lock(&sr_index_lock);
875 	clear_bit(MINOR(disk_devt(disk)), sr_index_bits);
876 	spin_unlock(&sr_index_lock);
877 
878 	unregister_cdrom(&cd->cdi);
879 
880 	disk->private_data = NULL;
881 
882 	put_disk(disk);
883 
884 	kfree(cd);
885 }
886 
887 static int sr_remove(struct device *dev)
888 {
889 	struct scsi_cd *cd = dev_get_drvdata(dev);
890 
891 	blk_queue_prep_rq(cd->device->request_queue, scsi_prep_fn);
892 	del_gendisk(cd->disk);
893 
894 	mutex_lock(&sr_ref_mutex);
895 	kref_put(&cd->kref, sr_kref_release);
896 	mutex_unlock(&sr_ref_mutex);
897 
898 	return 0;
899 }
900 
901 static int __init init_sr(void)
902 {
903 	int rc;
904 
905 	rc = register_blkdev(SCSI_CDROM_MAJOR, "sr");
906 	if (rc)
907 		return rc;
908 	rc = scsi_register_driver(&sr_template.gendrv);
909 	if (rc)
910 		unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
911 
912 	return rc;
913 }
914 
915 static void __exit exit_sr(void)
916 {
917 	scsi_unregister_driver(&sr_template.gendrv);
918 	unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
919 }
920 
921 module_init(init_sr);
922 module_exit(exit_sr);
923 MODULE_LICENSE("GPL");
924