xref: /linux/drivers/scsi/sr.c (revision 42fda66387daa53538ae13a2c858396aaf037158)
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 MAX_RETRIES	3
71 #define SR_TIMEOUT	(30 * HZ)
72 #define SR_CAPABILITIES \
73 	(CDC_CLOSE_TRAY|CDC_OPEN_TRAY|CDC_LOCK|CDC_SELECT_SPEED| \
74 	 CDC_SELECT_DISC|CDC_MULTI_SESSION|CDC_MCN|CDC_MEDIA_CHANGED| \
75 	 CDC_PLAY_AUDIO|CDC_RESET|CDC_DRIVE_STATUS| \
76 	 CDC_CD_R|CDC_CD_RW|CDC_DVD|CDC_DVD_R|CDC_DVD_RAM|CDC_GENERIC_PACKET| \
77 	 CDC_MRW|CDC_MRW_W|CDC_RAM)
78 
79 static int sr_probe(struct device *);
80 static int sr_remove(struct device *);
81 static int sr_done(struct scsi_cmnd *);
82 
83 static struct scsi_driver sr_template = {
84 	.owner			= THIS_MODULE,
85 	.gendrv = {
86 		.name   	= "sr",
87 		.probe		= sr_probe,
88 		.remove		= sr_remove,
89 	},
90 	.done			= sr_done,
91 };
92 
93 static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
94 static DEFINE_SPINLOCK(sr_index_lock);
95 
96 /* This semaphore is used to mediate the 0->1 reference get in the
97  * face of object destruction (i.e. we can't allow a get on an
98  * object after last put) */
99 static DEFINE_MUTEX(sr_ref_mutex);
100 
101 static int sr_open(struct cdrom_device_info *, int);
102 static void sr_release(struct cdrom_device_info *);
103 
104 static void get_sectorsize(struct scsi_cd *);
105 static void get_capabilities(struct scsi_cd *);
106 
107 static int sr_media_change(struct cdrom_device_info *, int);
108 static int sr_packet(struct cdrom_device_info *, struct packet_command *);
109 
110 static struct cdrom_device_ops sr_dops = {
111 	.open			= sr_open,
112 	.release	 	= sr_release,
113 	.drive_status	 	= sr_drive_status,
114 	.media_changed		= sr_media_change,
115 	.tray_move		= sr_tray_move,
116 	.lock_door		= sr_lock_door,
117 	.select_speed		= sr_select_speed,
118 	.get_last_session	= sr_get_last_session,
119 	.get_mcn		= sr_get_mcn,
120 	.reset			= sr_reset,
121 	.audio_ioctl		= sr_audio_ioctl,
122 	.capability		= SR_CAPABILITIES,
123 	.generic_packet		= sr_packet,
124 };
125 
126 static void sr_kref_release(struct kref *kref);
127 
128 static inline struct scsi_cd *scsi_cd(struct gendisk *disk)
129 {
130 	return container_of(disk->private_data, struct scsi_cd, driver);
131 }
132 
133 /*
134  * The get and put routines for the struct scsi_cd.  Note this entity
135  * has a scsi_device pointer and owns a reference to this.
136  */
137 static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk)
138 {
139 	struct scsi_cd *cd = NULL;
140 
141 	mutex_lock(&sr_ref_mutex);
142 	if (disk->private_data == NULL)
143 		goto out;
144 	cd = scsi_cd(disk);
145 	kref_get(&cd->kref);
146 	if (scsi_device_get(cd->device))
147 		goto out_put;
148 	goto out;
149 
150  out_put:
151 	kref_put(&cd->kref, sr_kref_release);
152 	cd = NULL;
153  out:
154 	mutex_unlock(&sr_ref_mutex);
155 	return cd;
156 }
157 
158 static void scsi_cd_put(struct scsi_cd *cd)
159 {
160 	struct scsi_device *sdev = cd->device;
161 
162 	mutex_lock(&sr_ref_mutex);
163 	kref_put(&cd->kref, sr_kref_release);
164 	scsi_device_put(sdev);
165 	mutex_unlock(&sr_ref_mutex);
166 }
167 
168 /*
169  * This function checks to see if the media has been changed in the
170  * CDROM drive.  It is possible that we have already sensed a change,
171  * or the drive may have sensed one and not yet reported it.  We must
172  * be ready for either case. This function always reports the current
173  * value of the changed bit.  If flag is 0, then the changed bit is reset.
174  * This function could be done as an ioctl, but we would need to have
175  * an inode for that to work, and we do not always have one.
176  */
177 
178 static int sr_media_change(struct cdrom_device_info *cdi, int slot)
179 {
180 	struct scsi_cd *cd = cdi->handle;
181 	int retval;
182 
183 	if (CDSL_CURRENT != slot) {
184 		/* no changer support */
185 		return -EINVAL;
186 	}
187 
188 	retval = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES);
189 	if (retval) {
190 		/* Unable to test, unit probably not ready.  This usually
191 		 * means there is no disc in the drive.  Mark as changed,
192 		 * and we will figure it out later once the drive is
193 		 * available again.  */
194 		cd->device->changed = 1;
195 		return 1;	/* This will force a flush, if called from
196 				 * check_disk_change */
197 	};
198 
199 	retval = cd->device->changed;
200 	cd->device->changed = 0;
201 	/* If the disk changed, the capacity will now be different,
202 	 * so we force a re-read of this information */
203 	if (retval) {
204 		/* check multisession offset etc */
205 		sr_cd_check(cdi);
206 
207 		get_sectorsize(cd);
208 	}
209 	return retval;
210 }
211 
212 /*
213  * sr_done is the interrupt routine for the device driver.
214  *
215  * It will be notified on the end of a SCSI read / write, and will take one
216  * of several actions based on success or failure.
217  */
218 static int sr_done(struct scsi_cmnd *SCpnt)
219 {
220 	int result = SCpnt->result;
221 	int this_count = SCpnt->request_bufflen;
222 	int good_bytes = (result == 0 ? this_count : 0);
223 	int block_sectors = 0;
224 	long error_sector;
225 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
226 
227 #ifdef DEBUG
228 	printk("sr.c done: %x\n", result);
229 #endif
230 
231 	/*
232 	 * Handle MEDIUM ERRORs or VOLUME OVERFLOWs that indicate partial
233 	 * success.  Since this is a relatively rare error condition, no
234 	 * care is taken to avoid unnecessary additional work such as
235 	 * memcpy's that could be avoided.
236 	 */
237 	if (driver_byte(result) != 0 &&		/* An error occurred */
238 	    (SCpnt->sense_buffer[0] & 0x7f) == 0x70) { /* Sense current */
239 		switch (SCpnt->sense_buffer[2]) {
240 		case MEDIUM_ERROR:
241 		case VOLUME_OVERFLOW:
242 		case ILLEGAL_REQUEST:
243 			if (!(SCpnt->sense_buffer[0] & 0x90))
244 				break;
245 			error_sector = (SCpnt->sense_buffer[3] << 24) |
246 				(SCpnt->sense_buffer[4] << 16) |
247 				(SCpnt->sense_buffer[5] << 8) |
248 				SCpnt->sense_buffer[6];
249 			if (SCpnt->request->bio != NULL)
250 				block_sectors =
251 					bio_sectors(SCpnt->request->bio);
252 			if (block_sectors < 4)
253 				block_sectors = 4;
254 			if (cd->device->sector_size == 2048)
255 				error_sector <<= 2;
256 			error_sector &= ~(block_sectors - 1);
257 			good_bytes = (error_sector - SCpnt->request->sector) << 9;
258 			if (good_bytes < 0 || good_bytes >= this_count)
259 				good_bytes = 0;
260 			/*
261 			 * The SCSI specification allows for the value
262 			 * returned by READ CAPACITY to be up to 75 2K
263 			 * sectors past the last readable block.
264 			 * Therefore, if we hit a medium error within the
265 			 * last 75 2K sectors, we decrease the saved size
266 			 * value.
267 			 */
268 			if (error_sector < get_capacity(cd->disk) &&
269 			    cd->capacity - error_sector < 4 * 75)
270 				set_capacity(cd->disk, error_sector);
271 			break;
272 
273 		case RECOVERED_ERROR:
274 
275 			/*
276 			 * An error occured, but it recovered.  Inform the
277 			 * user, but make sure that it's not treated as a
278 			 * hard error.
279 			 */
280 			scsi_print_sense("sr", SCpnt);
281 			SCpnt->result = 0;
282 			SCpnt->sense_buffer[0] = 0x0;
283 			good_bytes = this_count;
284 			break;
285 
286 		default:
287 			break;
288 		}
289 	}
290 
291 	return good_bytes;
292 }
293 
294 static int sr_prep_fn(struct request_queue *q, struct request *rq)
295 {
296 	int block=0, this_count, s_size, timeout = SR_TIMEOUT;
297 	struct scsi_cd *cd;
298 	struct scsi_cmnd *SCpnt;
299 	struct scsi_device *sdp = q->queuedata;
300 	int ret;
301 
302 	if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
303 		ret = scsi_setup_blk_pc_cmnd(sdp, rq);
304 		goto out;
305 	} else if (rq->cmd_type != REQ_TYPE_FS) {
306 		ret = BLKPREP_KILL;
307 		goto out;
308 	}
309 	ret = scsi_setup_fs_cmnd(sdp, rq);
310 	if (ret != BLKPREP_OK)
311 		goto out;
312 	SCpnt = rq->special;
313 	cd = scsi_cd(rq->rq_disk);
314 
315 	/* from here on until we're complete, any goto out
316 	 * is used for a killable error condition */
317 	ret = BLKPREP_KILL;
318 
319 	SCSI_LOG_HLQUEUE(1, printk("Doing sr request, dev = %s, block = %d\n",
320 				cd->disk->disk_name, block));
321 
322 	if (!cd->device || !scsi_device_online(cd->device)) {
323 		SCSI_LOG_HLQUEUE(2, printk("Finishing %ld sectors\n",
324 					rq->nr_sectors));
325 		SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
326 		goto out;
327 	}
328 
329 	if (cd->device->changed) {
330 		/*
331 		 * quietly refuse to do anything to a changed disc until the
332 		 * changed bit has been reset
333 		 */
334 		goto out;
335 	}
336 
337 	/*
338 	 * we do lazy blocksize switching (when reading XA sectors,
339 	 * see CDROMREADMODE2 ioctl)
340 	 */
341 	s_size = cd->device->sector_size;
342 	if (s_size > 2048) {
343 		if (!in_interrupt())
344 			sr_set_blocklength(cd, 2048);
345 		else
346 			printk("sr: can't switch blocksize: in interrupt\n");
347 	}
348 
349 	if (s_size != 512 && s_size != 1024 && s_size != 2048) {
350 		scmd_printk(KERN_ERR, SCpnt, "bad sector size %d\n", s_size);
351 		goto out;
352 	}
353 
354 	if (rq_data_dir(rq) == WRITE) {
355 		if (!cd->device->writeable)
356 			goto out;
357 		SCpnt->cmnd[0] = WRITE_10;
358 		SCpnt->sc_data_direction = DMA_TO_DEVICE;
359  	 	cd->cdi.media_written = 1;
360 	} else if (rq_data_dir(rq) == READ) {
361 		SCpnt->cmnd[0] = READ_10;
362 		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
363 	} else {
364 		blk_dump_rq_flags(rq, "Unknown sr command");
365 		goto out;
366 	}
367 
368 	{
369 		struct scatterlist *sg = SCpnt->request_buffer;
370 		int i, size = 0;
371 		for (i = 0; i < SCpnt->use_sg; i++)
372 			size += sg[i].length;
373 
374 		if (size != SCpnt->request_bufflen && SCpnt->use_sg) {
375 			scmd_printk(KERN_ERR, SCpnt,
376 				"mismatch count %d, bytes %d\n",
377 				size, SCpnt->request_bufflen);
378 			if (SCpnt->request_bufflen > size)
379 				SCpnt->request_bufflen = size;
380 		}
381 	}
382 
383 	/*
384 	 * request doesn't start on hw block boundary, add scatter pads
385 	 */
386 	if (((unsigned int)rq->sector % (s_size >> 9)) ||
387 	    (SCpnt->request_bufflen % s_size)) {
388 		scmd_printk(KERN_NOTICE, SCpnt, "unaligned transfer\n");
389 		goto out;
390 	}
391 
392 	this_count = (SCpnt->request_bufflen >> 9) / (s_size >> 9);
393 
394 
395 	SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n",
396 				cd->cdi.name,
397 				(rq_data_dir(rq) == WRITE) ?
398 					"writing" : "reading",
399 				this_count, rq->nr_sectors));
400 
401 	SCpnt->cmnd[1] = 0;
402 	block = (unsigned int)rq->sector / (s_size >> 9);
403 
404 	if (this_count > 0xffff) {
405 		this_count = 0xffff;
406 		SCpnt->request_bufflen = this_count * s_size;
407 	}
408 
409 	SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
410 	SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
411 	SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
412 	SCpnt->cmnd[5] = (unsigned char) block & 0xff;
413 	SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
414 	SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
415 	SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
416 
417 	/*
418 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
419 	 * host adapter, it's safe to assume that we can at least transfer
420 	 * this many bytes between each connect / disconnect.
421 	 */
422 	SCpnt->transfersize = cd->device->sector_size;
423 	SCpnt->underflow = this_count << 9;
424 	SCpnt->allowed = MAX_RETRIES;
425 	SCpnt->timeout_per_command = timeout;
426 
427 	/*
428 	 * This indicates that the command is ready from our end to be
429 	 * queued.
430 	 */
431 	ret = BLKPREP_OK;
432  out:
433 	return scsi_prep_return(q, rq, ret);
434 }
435 
436 static int sr_block_open(struct inode *inode, struct file *file)
437 {
438 	struct gendisk *disk = inode->i_bdev->bd_disk;
439 	struct scsi_cd *cd;
440 	int ret = 0;
441 
442 	if(!(cd = scsi_cd_get(disk)))
443 		return -ENXIO;
444 
445 	if((ret = cdrom_open(&cd->cdi, inode, file)) != 0)
446 		scsi_cd_put(cd);
447 
448 	return ret;
449 }
450 
451 static int sr_block_release(struct inode *inode, struct file *file)
452 {
453 	int ret;
454 	struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
455 	ret = cdrom_release(&cd->cdi, file);
456 	if(ret)
457 		return ret;
458 
459 	scsi_cd_put(cd);
460 
461 	return 0;
462 }
463 
464 static int sr_block_ioctl(struct inode *inode, struct file *file, unsigned cmd,
465 			  unsigned long arg)
466 {
467 	struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
468 	struct scsi_device *sdev = cd->device;
469 	void __user *argp = (void __user *)arg;
470 	int ret;
471 
472 	/*
473 	 * Send SCSI addressing ioctls directly to mid level, send other
474 	 * ioctls to cdrom/block level.
475 	 */
476 	switch (cmd) {
477 	case SCSI_IOCTL_GET_IDLUN:
478 	case SCSI_IOCTL_GET_BUS_NUMBER:
479 		return scsi_ioctl(sdev, cmd, argp);
480 	}
481 
482 	ret = cdrom_ioctl(file, &cd->cdi, inode, cmd, arg);
483 	if (ret != -ENOSYS)
484 		return ret;
485 
486 	/*
487 	 * ENODEV means that we didn't recognise the ioctl, or that we
488 	 * cannot execute it in the current device state.  In either
489 	 * case fall through to scsi_ioctl, which will return ENDOEV again
490 	 * if it doesn't recognise the ioctl
491 	 */
492 	ret = scsi_nonblockable_ioctl(sdev, cmd, argp, NULL);
493 	if (ret != -ENODEV)
494 		return ret;
495 	return scsi_ioctl(sdev, cmd, argp);
496 }
497 
498 static int sr_block_media_changed(struct gendisk *disk)
499 {
500 	struct scsi_cd *cd = scsi_cd(disk);
501 	return cdrom_media_changed(&cd->cdi);
502 }
503 
504 static struct block_device_operations sr_bdops =
505 {
506 	.owner		= THIS_MODULE,
507 	.open		= sr_block_open,
508 	.release	= sr_block_release,
509 	.ioctl		= sr_block_ioctl,
510 	.media_changed	= sr_block_media_changed,
511 	/*
512 	 * No compat_ioctl for now because sr_block_ioctl never
513 	 * seems to pass arbitary ioctls down to host drivers.
514 	 */
515 };
516 
517 static int sr_open(struct cdrom_device_info *cdi, int purpose)
518 {
519 	struct scsi_cd *cd = cdi->handle;
520 	struct scsi_device *sdev = cd->device;
521 	int retval;
522 
523 	/*
524 	 * If the device is in error recovery, wait until it is done.
525 	 * If the device is offline, then disallow any access to it.
526 	 */
527 	retval = -ENXIO;
528 	if (!scsi_block_when_processing_errors(sdev))
529 		goto error_out;
530 
531 	return 0;
532 
533 error_out:
534 	return retval;
535 }
536 
537 static void sr_release(struct cdrom_device_info *cdi)
538 {
539 	struct scsi_cd *cd = cdi->handle;
540 
541 	if (cd->device->sector_size > 2048)
542 		sr_set_blocklength(cd, 2048);
543 
544 }
545 
546 static int sr_probe(struct device *dev)
547 {
548 	struct scsi_device *sdev = to_scsi_device(dev);
549 	struct gendisk *disk;
550 	struct scsi_cd *cd;
551 	int minor, error;
552 
553 	error = -ENODEV;
554 	if (sdev->type != TYPE_ROM && sdev->type != TYPE_WORM)
555 		goto fail;
556 
557 	error = -ENOMEM;
558 	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
559 	if (!cd)
560 		goto fail;
561 
562 	kref_init(&cd->kref);
563 
564 	disk = alloc_disk(1);
565 	if (!disk)
566 		goto fail_free;
567 
568 	spin_lock(&sr_index_lock);
569 	minor = find_first_zero_bit(sr_index_bits, SR_DISKS);
570 	if (minor == SR_DISKS) {
571 		spin_unlock(&sr_index_lock);
572 		error = -EBUSY;
573 		goto fail_put;
574 	}
575 	__set_bit(minor, sr_index_bits);
576 	spin_unlock(&sr_index_lock);
577 
578 	disk->major = SCSI_CDROM_MAJOR;
579 	disk->first_minor = minor;
580 	sprintf(disk->disk_name, "sr%d", minor);
581 	disk->fops = &sr_bdops;
582 	disk->flags = GENHD_FL_CD;
583 
584 	cd->device = sdev;
585 	cd->disk = disk;
586 	cd->driver = &sr_template;
587 	cd->disk = disk;
588 	cd->capacity = 0x1fffff;
589 	cd->device->changed = 1;	/* force recheck CD type */
590 	cd->use = 1;
591 	cd->readcd_known = 0;
592 	cd->readcd_cdda = 0;
593 
594 	cd->cdi.ops = &sr_dops;
595 	cd->cdi.handle = cd;
596 	cd->cdi.mask = 0;
597 	cd->cdi.capacity = 1;
598 	sprintf(cd->cdi.name, "sr%d", minor);
599 
600 	sdev->sector_size = 2048;	/* A guess, just in case */
601 
602 	/* FIXME: need to handle a get_capabilities failure properly ?? */
603 	get_capabilities(cd);
604 	blk_queue_prep_rq(sdev->request_queue, sr_prep_fn);
605 	sr_vendor_init(cd);
606 
607 	disk->driverfs_dev = &sdev->sdev_gendev;
608 	set_capacity(disk, cd->capacity);
609 	disk->private_data = &cd->driver;
610 	disk->queue = sdev->request_queue;
611 	cd->cdi.disk = disk;
612 
613 	if (register_cdrom(&cd->cdi))
614 		goto fail_put;
615 
616 	dev_set_drvdata(dev, cd);
617 	disk->flags |= GENHD_FL_REMOVABLE;
618 	add_disk(disk);
619 
620 	sdev_printk(KERN_DEBUG, sdev,
621 		    "Attached scsi CD-ROM %s\n", cd->cdi.name);
622 	return 0;
623 
624 fail_put:
625 	put_disk(disk);
626 fail_free:
627 	kfree(cd);
628 fail:
629 	return error;
630 }
631 
632 
633 static void get_sectorsize(struct scsi_cd *cd)
634 {
635 	unsigned char cmd[10];
636 	unsigned char *buffer;
637 	int the_result, retries = 3;
638 	int sector_size;
639 	struct request_queue *queue;
640 
641 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
642 	if (!buffer)
643 		goto Enomem;
644 
645 	do {
646 		cmd[0] = READ_CAPACITY;
647 		memset((void *) &cmd[1], 0, 9);
648 		memset(buffer, 0, 8);
649 
650 		/* Do the command and wait.. */
651 		the_result = scsi_execute_req(cd->device, cmd, DMA_FROM_DEVICE,
652 					      buffer, 8, NULL, SR_TIMEOUT,
653 					      MAX_RETRIES);
654 
655 		retries--;
656 
657 	} while (the_result && retries);
658 
659 
660 	if (the_result) {
661 		cd->capacity = 0x1fffff;
662 		sector_size = 2048;	/* A guess, just in case */
663 	} else {
664 #if 0
665 		if (cdrom_get_last_written(&cd->cdi,
666 					   &cd->capacity))
667 #endif
668 			cd->capacity = 1 + ((buffer[0] << 24) |
669 						    (buffer[1] << 16) |
670 						    (buffer[2] << 8) |
671 						    buffer[3]);
672 		sector_size = (buffer[4] << 24) |
673 		    (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
674 		switch (sector_size) {
675 			/*
676 			 * HP 4020i CD-Recorder reports 2340 byte sectors
677 			 * Philips CD-Writers report 2352 byte sectors
678 			 *
679 			 * Use 2k sectors for them..
680 			 */
681 		case 0:
682 		case 2340:
683 		case 2352:
684 			sector_size = 2048;
685 			/* fall through */
686 		case 2048:
687 			cd->capacity *= 4;
688 			/* fall through */
689 		case 512:
690 			break;
691 		default:
692 			printk("%s: unsupported sector size %d.\n",
693 			       cd->cdi.name, sector_size);
694 			cd->capacity = 0;
695 		}
696 
697 		cd->device->sector_size = sector_size;
698 
699 		/*
700 		 * Add this so that we have the ability to correctly gauge
701 		 * what the device is capable of.
702 		 */
703 		set_capacity(cd->disk, cd->capacity);
704 	}
705 
706 	queue = cd->device->request_queue;
707 	blk_queue_hardsect_size(queue, sector_size);
708 out:
709 	kfree(buffer);
710 	return;
711 
712 Enomem:
713 	cd->capacity = 0x1fffff;
714 	cd->device->sector_size = 2048;	/* A guess, just in case */
715 	goto out;
716 }
717 
718 static void get_capabilities(struct scsi_cd *cd)
719 {
720 	unsigned char *buffer;
721 	struct scsi_mode_data data;
722 	unsigned char cmd[MAX_COMMAND_SIZE];
723 	struct scsi_sense_hdr sshdr;
724 	unsigned int the_result;
725 	int retries, rc, n;
726 
727 	static const char *loadmech[] =
728 	{
729 		"caddy",
730 		"tray",
731 		"pop-up",
732 		"",
733 		"changer",
734 		"cartridge changer",
735 		"",
736 		""
737 	};
738 
739 
740 	/* allocate transfer buffer */
741 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
742 	if (!buffer) {
743 		printk(KERN_ERR "sr: out of memory.\n");
744 		return;
745 	}
746 
747 	/* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
748 	 * conditions are gone, or a timeout happens
749 	 */
750 	retries = 0;
751 	do {
752 		memset((void *)cmd, 0, MAX_COMMAND_SIZE);
753 		cmd[0] = TEST_UNIT_READY;
754 
755 		the_result = scsi_execute_req (cd->device, cmd, DMA_NONE, NULL,
756 					       0, &sshdr, SR_TIMEOUT,
757 					       MAX_RETRIES);
758 
759 		retries++;
760 	} while (retries < 5 &&
761 		 (!scsi_status_is_good(the_result) ||
762 		  (scsi_sense_valid(&sshdr) &&
763 		   sshdr.sense_key == UNIT_ATTENTION)));
764 
765 	/* ask for mode page 0x2a */
766 	rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128,
767 			     SR_TIMEOUT, 3, &data, NULL);
768 
769 	if (!scsi_status_is_good(rc)) {
770 		/* failed, drive doesn't have capabilities mode page */
771 		cd->cdi.speed = 1;
772 		cd->cdi.mask |= (CDC_CD_R | CDC_CD_RW | CDC_DVD_R |
773 				 CDC_DVD | CDC_DVD_RAM |
774 				 CDC_SELECT_DISC | CDC_SELECT_SPEED |
775 				 CDC_MRW | CDC_MRW_W | CDC_RAM);
776 		kfree(buffer);
777 		printk("%s: scsi-1 drive\n", cd->cdi.name);
778 		return;
779 	}
780 
781 	n = data.header_length + data.block_descriptor_length;
782 	cd->cdi.speed = ((buffer[n + 8] << 8) + buffer[n + 9]) / 176;
783 	cd->readcd_known = 1;
784 	cd->readcd_cdda = buffer[n + 5] & 0x01;
785 	/* print some capability bits */
786 	printk("%s: scsi3-mmc drive: %dx/%dx %s%s%s%s%s%s\n", cd->cdi.name,
787 	       ((buffer[n + 14] << 8) + buffer[n + 15]) / 176,
788 	       cd->cdi.speed,
789 	       buffer[n + 3] & 0x01 ? "writer " : "", /* CD Writer */
790 	       buffer[n + 3] & 0x20 ? "dvd-ram " : "",
791 	       buffer[n + 2] & 0x02 ? "cd/rw " : "", /* can read rewriteable */
792 	       buffer[n + 4] & 0x20 ? "xa/form2 " : "",	/* can read xa/from2 */
793 	       buffer[n + 5] & 0x01 ? "cdda " : "", /* can read audio data */
794 	       loadmech[buffer[n + 6] >> 5]);
795 	if ((buffer[n + 6] >> 5) == 0)
796 		/* caddy drives can't close tray... */
797 		cd->cdi.mask |= CDC_CLOSE_TRAY;
798 	if ((buffer[n + 2] & 0x8) == 0)
799 		/* not a DVD drive */
800 		cd->cdi.mask |= CDC_DVD;
801 	if ((buffer[n + 3] & 0x20) == 0)
802 		/* can't write DVD-RAM media */
803 		cd->cdi.mask |= CDC_DVD_RAM;
804 	if ((buffer[n + 3] & 0x10) == 0)
805 		/* can't write DVD-R media */
806 		cd->cdi.mask |= CDC_DVD_R;
807 	if ((buffer[n + 3] & 0x2) == 0)
808 		/* can't write CD-RW media */
809 		cd->cdi.mask |= CDC_CD_RW;
810 	if ((buffer[n + 3] & 0x1) == 0)
811 		/* can't write CD-R media */
812 		cd->cdi.mask |= CDC_CD_R;
813 	if ((buffer[n + 6] & 0x8) == 0)
814 		/* can't eject */
815 		cd->cdi.mask |= CDC_OPEN_TRAY;
816 
817 	if ((buffer[n + 6] >> 5) == mechtype_individual_changer ||
818 	    (buffer[n + 6] >> 5) == mechtype_cartridge_changer)
819 		cd->cdi.capacity =
820 		    cdrom_number_of_slots(&cd->cdi);
821 	if (cd->cdi.capacity <= 1)
822 		/* not a changer */
823 		cd->cdi.mask |= CDC_SELECT_DISC;
824 	/*else    I don't think it can close its tray
825 		cd->cdi.mask |= CDC_CLOSE_TRAY; */
826 
827 	/*
828 	 * if DVD-RAM, MRW-W or CD-RW, we are randomly writable
829 	 */
830 	if ((cd->cdi.mask & (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) !=
831 			(CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) {
832 		cd->device->writeable = 1;
833 	}
834 
835 	kfree(buffer);
836 }
837 
838 /*
839  * sr_packet() is the entry point for the generic commands generated
840  * by the Uniform CD-ROM layer.
841  */
842 static int sr_packet(struct cdrom_device_info *cdi,
843 		struct packet_command *cgc)
844 {
845 	if (cgc->timeout <= 0)
846 		cgc->timeout = IOCTL_TIMEOUT;
847 
848 	sr_do_ioctl(cdi->handle, cgc);
849 
850 	return cgc->stat;
851 }
852 
853 /**
854  *	sr_kref_release - Called to free the scsi_cd structure
855  *	@kref: pointer to embedded kref
856  *
857  *	sr_ref_mutex must be held entering this routine.  Because it is
858  *	called on last put, you should always use the scsi_cd_get()
859  *	scsi_cd_put() helpers which manipulate the semaphore directly
860  *	and never do a direct kref_put().
861  **/
862 static void sr_kref_release(struct kref *kref)
863 {
864 	struct scsi_cd *cd = container_of(kref, struct scsi_cd, kref);
865 	struct gendisk *disk = cd->disk;
866 
867 	spin_lock(&sr_index_lock);
868 	clear_bit(disk->first_minor, sr_index_bits);
869 	spin_unlock(&sr_index_lock);
870 
871 	unregister_cdrom(&cd->cdi);
872 
873 	disk->private_data = NULL;
874 
875 	put_disk(disk);
876 
877 	kfree(cd);
878 }
879 
880 static int sr_remove(struct device *dev)
881 {
882 	struct scsi_cd *cd = dev_get_drvdata(dev);
883 
884 	del_gendisk(cd->disk);
885 
886 	mutex_lock(&sr_ref_mutex);
887 	kref_put(&cd->kref, sr_kref_release);
888 	mutex_unlock(&sr_ref_mutex);
889 
890 	return 0;
891 }
892 
893 static int __init init_sr(void)
894 {
895 	int rc;
896 
897 	rc = register_blkdev(SCSI_CDROM_MAJOR, "sr");
898 	if (rc)
899 		return rc;
900 	rc = scsi_register_driver(&sr_template.gendrv);
901 	if (rc)
902 		unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
903 
904 	return rc;
905 }
906 
907 static void __exit exit_sr(void)
908 {
909 	scsi_unregister_driver(&sr_template.gendrv);
910 	unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
911 }
912 
913 module_init(init_sr);
914 module_exit(exit_sr);
915 MODULE_LICENSE("GPL");
916