xref: /openbmc/linux/drivers/scsi/sr.c (revision e29dc460)
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 <linux/pm_runtime.h>
49 #include <linux/uaccess.h>
50 
51 #include <scsi/scsi.h>
52 #include <scsi/scsi_dbg.h>
53 #include <scsi/scsi_device.h>
54 #include <scsi/scsi_driver.h>
55 #include <scsi/scsi_cmnd.h>
56 #include <scsi/scsi_eh.h>
57 #include <scsi/scsi_host.h>
58 #include <scsi/scsi_ioctl.h>	/* For the door lock/unlock commands */
59 
60 #include "scsi_logging.h"
61 #include "sr.h"
62 
63 
64 MODULE_DESCRIPTION("SCSI cdrom (sr) driver");
65 MODULE_LICENSE("GPL");
66 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_CDROM_MAJOR);
67 MODULE_ALIAS_SCSI_DEVICE(TYPE_ROM);
68 MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);
69 
70 #define SR_DISKS	256
71 
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 DEFINE_MUTEX(sr_mutex);
80 static int sr_probe(struct device *);
81 static int sr_remove(struct device *);
82 static int sr_init_command(struct scsi_cmnd *SCpnt);
83 static int sr_done(struct scsi_cmnd *);
84 static int sr_runtime_suspend(struct device *dev);
85 
86 static const struct dev_pm_ops sr_pm_ops = {
87 	.runtime_suspend	= sr_runtime_suspend,
88 };
89 
90 static struct scsi_driver sr_template = {
91 	.gendrv = {
92 		.name   	= "sr",
93 		.owner		= THIS_MODULE,
94 		.probe		= sr_probe,
95 		.remove		= sr_remove,
96 		.pm		= &sr_pm_ops,
97 	},
98 	.init_command		= sr_init_command,
99 	.done			= sr_done,
100 };
101 
102 static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
103 static DEFINE_SPINLOCK(sr_index_lock);
104 
105 /* This semaphore is used to mediate the 0->1 reference get in the
106  * face of object destruction (i.e. we can't allow a get on an
107  * object after last put) */
108 static DEFINE_MUTEX(sr_ref_mutex);
109 
110 static int sr_open(struct cdrom_device_info *, int);
111 static void sr_release(struct cdrom_device_info *);
112 
113 static void get_sectorsize(struct scsi_cd *);
114 static void get_capabilities(struct scsi_cd *);
115 
116 static unsigned int sr_check_events(struct cdrom_device_info *cdi,
117 				    unsigned int clearing, int slot);
118 static int sr_packet(struct cdrom_device_info *, struct packet_command *);
119 
120 static const struct cdrom_device_ops sr_dops = {
121 	.open			= sr_open,
122 	.release	 	= sr_release,
123 	.drive_status	 	= sr_drive_status,
124 	.check_events		= sr_check_events,
125 	.tray_move		= sr_tray_move,
126 	.lock_door		= sr_lock_door,
127 	.select_speed		= sr_select_speed,
128 	.get_last_session	= sr_get_last_session,
129 	.get_mcn		= sr_get_mcn,
130 	.reset			= sr_reset,
131 	.audio_ioctl		= sr_audio_ioctl,
132 	.capability		= SR_CAPABILITIES,
133 	.generic_packet		= sr_packet,
134 };
135 
136 static void sr_kref_release(struct kref *kref);
137 
138 static inline struct scsi_cd *scsi_cd(struct gendisk *disk)
139 {
140 	return container_of(disk->private_data, struct scsi_cd, driver);
141 }
142 
143 static int sr_runtime_suspend(struct device *dev)
144 {
145 	struct scsi_cd *cd = dev_get_drvdata(dev);
146 
147 	if (!cd)	/* E.g.: runtime suspend following sr_remove() */
148 		return 0;
149 
150 	if (cd->media_present)
151 		return -EBUSY;
152 	else
153 		return 0;
154 }
155 
156 /*
157  * The get and put routines for the struct scsi_cd.  Note this entity
158  * has a scsi_device pointer and owns a reference to this.
159  */
160 static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk)
161 {
162 	struct scsi_cd *cd = NULL;
163 
164 	mutex_lock(&sr_ref_mutex);
165 	if (disk->private_data == NULL)
166 		goto out;
167 	cd = scsi_cd(disk);
168 	kref_get(&cd->kref);
169 	if (scsi_device_get(cd->device)) {
170 		kref_put(&cd->kref, sr_kref_release);
171 		cd = NULL;
172 	}
173  out:
174 	mutex_unlock(&sr_ref_mutex);
175 	return cd;
176 }
177 
178 static void scsi_cd_put(struct scsi_cd *cd)
179 {
180 	struct scsi_device *sdev = cd->device;
181 
182 	mutex_lock(&sr_ref_mutex);
183 	kref_put(&cd->kref, sr_kref_release);
184 	scsi_device_put(sdev);
185 	mutex_unlock(&sr_ref_mutex);
186 }
187 
188 static unsigned int sr_get_events(struct scsi_device *sdev)
189 {
190 	u8 buf[8];
191 	u8 cmd[] = { GET_EVENT_STATUS_NOTIFICATION,
192 		     1,			/* polled */
193 		     0, 0,		/* reserved */
194 		     1 << 4,		/* notification class: media */
195 		     0, 0,		/* reserved */
196 		     0, sizeof(buf),	/* allocation length */
197 		     0,			/* control */
198 	};
199 	struct event_header *eh = (void *)buf;
200 	struct media_event_desc *med = (void *)(buf + 4);
201 	struct scsi_sense_hdr sshdr;
202 	int result;
203 
204 	result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buf, sizeof(buf),
205 				  &sshdr, SR_TIMEOUT, MAX_RETRIES, NULL);
206 	if (scsi_sense_valid(&sshdr) && sshdr.sense_key == UNIT_ATTENTION)
207 		return DISK_EVENT_MEDIA_CHANGE;
208 
209 	if (result || be16_to_cpu(eh->data_len) < sizeof(*med))
210 		return 0;
211 
212 	if (eh->nea || eh->notification_class != 0x4)
213 		return 0;
214 
215 	if (med->media_event_code == 1)
216 		return DISK_EVENT_EJECT_REQUEST;
217 	else if (med->media_event_code == 2)
218 		return DISK_EVENT_MEDIA_CHANGE;
219 	return 0;
220 }
221 
222 /*
223  * This function checks to see if the media has been changed or eject
224  * button has been pressed.  It is possible that we have already
225  * sensed a change, or the drive may have sensed one and not yet
226  * reported it.  The past events are accumulated in sdev->changed and
227  * returned together with the current state.
228  */
229 static unsigned int sr_check_events(struct cdrom_device_info *cdi,
230 				    unsigned int clearing, int slot)
231 {
232 	struct scsi_cd *cd = cdi->handle;
233 	bool last_present;
234 	struct scsi_sense_hdr sshdr;
235 	unsigned int events;
236 	int ret;
237 
238 	/* no changer support */
239 	if (CDSL_CURRENT != slot)
240 		return 0;
241 
242 	events = sr_get_events(cd->device);
243 	cd->get_event_changed |= events & DISK_EVENT_MEDIA_CHANGE;
244 
245 	/*
246 	 * If earlier GET_EVENT_STATUS_NOTIFICATION and TUR did not agree
247 	 * for several times in a row.  We rely on TUR only for this likely
248 	 * broken device, to prevent generating incorrect media changed
249 	 * events for every open().
250 	 */
251 	if (cd->ignore_get_event) {
252 		events &= ~DISK_EVENT_MEDIA_CHANGE;
253 		goto do_tur;
254 	}
255 
256 	/*
257 	 * GET_EVENT_STATUS_NOTIFICATION is enough unless MEDIA_CHANGE
258 	 * is being cleared.  Note that there are devices which hang
259 	 * if asked to execute TUR repeatedly.
260 	 */
261 	if (cd->device->changed) {
262 		events |= DISK_EVENT_MEDIA_CHANGE;
263 		cd->device->changed = 0;
264 		cd->tur_changed = true;
265 	}
266 
267 	if (!(clearing & DISK_EVENT_MEDIA_CHANGE))
268 		return events;
269 do_tur:
270 	/* let's see whether the media is there with TUR */
271 	last_present = cd->media_present;
272 	ret = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
273 
274 	/*
275 	 * Media is considered to be present if TUR succeeds or fails with
276 	 * sense data indicating something other than media-not-present
277 	 * (ASC 0x3a).
278 	 */
279 	cd->media_present = scsi_status_is_good(ret) ||
280 		(scsi_sense_valid(&sshdr) && sshdr.asc != 0x3a);
281 
282 	if (last_present != cd->media_present)
283 		cd->device->changed = 1;
284 
285 	if (cd->device->changed) {
286 		events |= DISK_EVENT_MEDIA_CHANGE;
287 		cd->device->changed = 0;
288 		cd->tur_changed = true;
289 	}
290 
291 	if (cd->ignore_get_event)
292 		return events;
293 
294 	/* check whether GET_EVENT is reporting spurious MEDIA_CHANGE */
295 	if (!cd->tur_changed) {
296 		if (cd->get_event_changed) {
297 			if (cd->tur_mismatch++ > 8) {
298 				sr_printk(KERN_WARNING, cd,
299 					  "GET_EVENT and TUR disagree continuously, suppress GET_EVENT events\n");
300 				cd->ignore_get_event = true;
301 			}
302 		} else {
303 			cd->tur_mismatch = 0;
304 		}
305 	}
306 	cd->tur_changed = false;
307 	cd->get_event_changed = false;
308 
309 	return events;
310 }
311 
312 /*
313  * sr_done is the interrupt routine for the device driver.
314  *
315  * It will be notified on the end of a SCSI read / write, and will take one
316  * of several actions based on success or failure.
317  */
318 static int sr_done(struct scsi_cmnd *SCpnt)
319 {
320 	int result = SCpnt->result;
321 	int this_count = scsi_bufflen(SCpnt);
322 	int good_bytes = (result == 0 ? this_count : 0);
323 	int block_sectors = 0;
324 	long error_sector;
325 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
326 
327 #ifdef DEBUG
328 	scmd_printk(KERN_INFO, SCpnt, "done: %x\n", result);
329 #endif
330 
331 	/*
332 	 * Handle MEDIUM ERRORs or VOLUME OVERFLOWs that indicate partial
333 	 * success.  Since this is a relatively rare error condition, no
334 	 * care is taken to avoid unnecessary additional work such as
335 	 * memcpy's that could be avoided.
336 	 */
337 	if (driver_byte(result) != 0 &&		/* An error occurred */
338 	    (SCpnt->sense_buffer[0] & 0x7f) == 0x70) { /* Sense current */
339 		switch (SCpnt->sense_buffer[2]) {
340 		case MEDIUM_ERROR:
341 		case VOLUME_OVERFLOW:
342 		case ILLEGAL_REQUEST:
343 			if (!(SCpnt->sense_buffer[0] & 0x90))
344 				break;
345 			error_sector = (SCpnt->sense_buffer[3] << 24) |
346 				(SCpnt->sense_buffer[4] << 16) |
347 				(SCpnt->sense_buffer[5] << 8) |
348 				SCpnt->sense_buffer[6];
349 			if (SCpnt->request->bio != NULL)
350 				block_sectors =
351 					bio_sectors(SCpnt->request->bio);
352 			if (block_sectors < 4)
353 				block_sectors = 4;
354 			if (cd->device->sector_size == 2048)
355 				error_sector <<= 2;
356 			error_sector &= ~(block_sectors - 1);
357 			good_bytes = (error_sector -
358 				      blk_rq_pos(SCpnt->request)) << 9;
359 			if (good_bytes < 0 || good_bytes >= this_count)
360 				good_bytes = 0;
361 			/*
362 			 * The SCSI specification allows for the value
363 			 * returned by READ CAPACITY to be up to 75 2K
364 			 * sectors past the last readable block.
365 			 * Therefore, if we hit a medium error within the
366 			 * last 75 2K sectors, we decrease the saved size
367 			 * value.
368 			 */
369 			if (error_sector < get_capacity(cd->disk) &&
370 			    cd->capacity - error_sector < 4 * 75)
371 				set_capacity(cd->disk, error_sector);
372 			break;
373 
374 		case RECOVERED_ERROR:
375 			good_bytes = this_count;
376 			break;
377 
378 		default:
379 			break;
380 		}
381 	}
382 
383 	return good_bytes;
384 }
385 
386 static int sr_init_command(struct scsi_cmnd *SCpnt)
387 {
388 	int block = 0, this_count, s_size;
389 	struct scsi_cd *cd;
390 	struct request *rq = SCpnt->request;
391 	int ret;
392 
393 	ret = scsi_init_io(SCpnt);
394 	if (ret != BLKPREP_OK)
395 		goto out;
396 	WARN_ON_ONCE(SCpnt != rq->special);
397 	cd = scsi_cd(rq->rq_disk);
398 
399 	/* from here on until we're complete, any goto out
400 	 * is used for a killable error condition */
401 	ret = BLKPREP_KILL;
402 
403 	SCSI_LOG_HLQUEUE(1, scmd_printk(KERN_INFO, SCpnt,
404 		"Doing sr request, block = %d\n", block));
405 
406 	if (!cd->device || !scsi_device_online(cd->device)) {
407 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
408 			"Finishing %u sectors\n", blk_rq_sectors(rq)));
409 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
410 			"Retry with 0x%p\n", SCpnt));
411 		goto out;
412 	}
413 
414 	if (cd->device->changed) {
415 		/*
416 		 * quietly refuse to do anything to a changed disc until the
417 		 * changed bit has been reset
418 		 */
419 		goto out;
420 	}
421 
422 	/*
423 	 * we do lazy blocksize switching (when reading XA sectors,
424 	 * see CDROMREADMODE2 ioctl)
425 	 */
426 	s_size = cd->device->sector_size;
427 	if (s_size > 2048) {
428 		if (!in_interrupt())
429 			sr_set_blocklength(cd, 2048);
430 		else
431 			scmd_printk(KERN_INFO, SCpnt,
432 				    "can't switch blocksize: in interrupt\n");
433 	}
434 
435 	if (s_size != 512 && s_size != 1024 && s_size != 2048) {
436 		scmd_printk(KERN_ERR, SCpnt, "bad sector size %d\n", s_size);
437 		goto out;
438 	}
439 
440 	switch (req_op(rq)) {
441 	case REQ_OP_WRITE:
442 		if (!cd->writeable)
443 			goto out;
444 		SCpnt->cmnd[0] = WRITE_10;
445 		cd->cdi.media_written = 1;
446 		break;
447 	case REQ_OP_READ:
448 		SCpnt->cmnd[0] = READ_10;
449 		break;
450 	default:
451 		blk_dump_rq_flags(rq, "Unknown sr command");
452 		goto out;
453 	}
454 
455 	{
456 		struct scatterlist *sg;
457 		int i, size = 0, sg_count = scsi_sg_count(SCpnt);
458 
459 		scsi_for_each_sg(SCpnt, sg, sg_count, i)
460 			size += sg->length;
461 
462 		if (size != scsi_bufflen(SCpnt)) {
463 			scmd_printk(KERN_ERR, SCpnt,
464 				"mismatch count %d, bytes %d\n",
465 				size, scsi_bufflen(SCpnt));
466 			if (scsi_bufflen(SCpnt) > size)
467 				SCpnt->sdb.length = size;
468 		}
469 	}
470 
471 	/*
472 	 * request doesn't start on hw block boundary, add scatter pads
473 	 */
474 	if (((unsigned int)blk_rq_pos(rq) % (s_size >> 9)) ||
475 	    (scsi_bufflen(SCpnt) % s_size)) {
476 		scmd_printk(KERN_NOTICE, SCpnt, "unaligned transfer\n");
477 		goto out;
478 	}
479 
480 	this_count = (scsi_bufflen(SCpnt) >> 9) / (s_size >> 9);
481 
482 
483 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
484 					"%s %d/%u 512 byte blocks.\n",
485 					(rq_data_dir(rq) == WRITE) ?
486 					"writing" : "reading",
487 					this_count, blk_rq_sectors(rq)));
488 
489 	SCpnt->cmnd[1] = 0;
490 	block = (unsigned int)blk_rq_pos(rq) / (s_size >> 9);
491 
492 	if (this_count > 0xffff) {
493 		this_count = 0xffff;
494 		SCpnt->sdb.length = this_count * s_size;
495 	}
496 
497 	SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
498 	SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
499 	SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
500 	SCpnt->cmnd[5] = (unsigned char) block & 0xff;
501 	SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
502 	SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
503 	SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
504 
505 	/*
506 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
507 	 * host adapter, it's safe to assume that we can at least transfer
508 	 * this many bytes between each connect / disconnect.
509 	 */
510 	SCpnt->transfersize = cd->device->sector_size;
511 	SCpnt->underflow = this_count << 9;
512 	SCpnt->allowed = MAX_RETRIES;
513 
514 	/*
515 	 * This indicates that the command is ready from our end to be
516 	 * queued.
517 	 */
518 	ret = BLKPREP_OK;
519  out:
520 	return ret;
521 }
522 
523 static int sr_block_open(struct block_device *bdev, fmode_t mode)
524 {
525 	struct scsi_cd *cd;
526 	int ret = -ENXIO;
527 
528 	check_disk_change(bdev);
529 
530 	mutex_lock(&sr_mutex);
531 	cd = scsi_cd_get(bdev->bd_disk);
532 	if (cd) {
533 		ret = cdrom_open(&cd->cdi, bdev, mode);
534 		if (ret)
535 			scsi_cd_put(cd);
536 	}
537 	mutex_unlock(&sr_mutex);
538 	return ret;
539 }
540 
541 static void sr_block_release(struct gendisk *disk, fmode_t mode)
542 {
543 	struct scsi_cd *cd = scsi_cd(disk);
544 	mutex_lock(&sr_mutex);
545 	cdrom_release(&cd->cdi, mode);
546 	scsi_cd_put(cd);
547 	mutex_unlock(&sr_mutex);
548 }
549 
550 static int sr_block_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
551 			  unsigned long arg)
552 {
553 	struct scsi_cd *cd = scsi_cd(bdev->bd_disk);
554 	struct scsi_device *sdev = cd->device;
555 	void __user *argp = (void __user *)arg;
556 	int ret;
557 
558 	mutex_lock(&sr_mutex);
559 
560 	ret = scsi_ioctl_block_when_processing_errors(sdev, cmd,
561 			(mode & FMODE_NDELAY) != 0);
562 	if (ret)
563 		goto out;
564 
565 	/*
566 	 * Send SCSI addressing ioctls directly to mid level, send other
567 	 * ioctls to cdrom/block level.
568 	 */
569 	switch (cmd) {
570 	case SCSI_IOCTL_GET_IDLUN:
571 	case SCSI_IOCTL_GET_BUS_NUMBER:
572 		ret = scsi_ioctl(sdev, cmd, argp);
573 		goto out;
574 	}
575 
576 	ret = cdrom_ioctl(&cd->cdi, bdev, mode, cmd, arg);
577 	if (ret != -ENOSYS)
578 		goto out;
579 
580 	ret = scsi_ioctl(sdev, cmd, argp);
581 
582 out:
583 	mutex_unlock(&sr_mutex);
584 	return ret;
585 }
586 
587 static unsigned int sr_block_check_events(struct gendisk *disk,
588 					  unsigned int clearing)
589 {
590 	unsigned int ret = 0;
591 	struct scsi_cd *cd;
592 
593 	cd = scsi_cd_get(disk);
594 	if (!cd)
595 		return 0;
596 
597 	if (!atomic_read(&cd->device->disk_events_disable_depth))
598 		ret = cdrom_check_events(&cd->cdi, clearing);
599 
600 	scsi_cd_put(cd);
601 	return ret;
602 }
603 
604 static int sr_block_revalidate_disk(struct gendisk *disk)
605 {
606 	struct scsi_sense_hdr sshdr;
607 	struct scsi_cd *cd;
608 
609 	cd = scsi_cd_get(disk);
610 	if (!cd)
611 		return -ENXIO;
612 
613 	/* if the unit is not ready, nothing more to do */
614 	if (scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr))
615 		goto out;
616 
617 	sr_cd_check(&cd->cdi);
618 	get_sectorsize(cd);
619 out:
620 	scsi_cd_put(cd);
621 	return 0;
622 }
623 
624 static const struct block_device_operations sr_bdops =
625 {
626 	.owner		= THIS_MODULE,
627 	.open		= sr_block_open,
628 	.release	= sr_block_release,
629 	.ioctl		= sr_block_ioctl,
630 	.check_events	= sr_block_check_events,
631 	.revalidate_disk = sr_block_revalidate_disk,
632 	/*
633 	 * No compat_ioctl for now because sr_block_ioctl never
634 	 * seems to pass arbitrary ioctls down to host drivers.
635 	 */
636 };
637 
638 static int sr_open(struct cdrom_device_info *cdi, int purpose)
639 {
640 	struct scsi_cd *cd = cdi->handle;
641 	struct scsi_device *sdev = cd->device;
642 	int retval;
643 
644 	/*
645 	 * If the device is in error recovery, wait until it is done.
646 	 * If the device is offline, then disallow any access to it.
647 	 */
648 	retval = -ENXIO;
649 	if (!scsi_block_when_processing_errors(sdev))
650 		goto error_out;
651 
652 	return 0;
653 
654 error_out:
655 	return retval;
656 }
657 
658 static void sr_release(struct cdrom_device_info *cdi)
659 {
660 	struct scsi_cd *cd = cdi->handle;
661 
662 	if (cd->device->sector_size > 2048)
663 		sr_set_blocklength(cd, 2048);
664 
665 }
666 
667 static int sr_probe(struct device *dev)
668 {
669 	struct scsi_device *sdev = to_scsi_device(dev);
670 	struct gendisk *disk;
671 	struct scsi_cd *cd;
672 	int minor, error;
673 
674 	scsi_autopm_get_device(sdev);
675 	error = -ENODEV;
676 	if (sdev->type != TYPE_ROM && sdev->type != TYPE_WORM)
677 		goto fail;
678 
679 	error = -ENOMEM;
680 	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
681 	if (!cd)
682 		goto fail;
683 
684 	kref_init(&cd->kref);
685 
686 	disk = alloc_disk(1);
687 	if (!disk)
688 		goto fail_free;
689 
690 	spin_lock(&sr_index_lock);
691 	minor = find_first_zero_bit(sr_index_bits, SR_DISKS);
692 	if (minor == SR_DISKS) {
693 		spin_unlock(&sr_index_lock);
694 		error = -EBUSY;
695 		goto fail_put;
696 	}
697 	__set_bit(minor, sr_index_bits);
698 	spin_unlock(&sr_index_lock);
699 
700 	disk->major = SCSI_CDROM_MAJOR;
701 	disk->first_minor = minor;
702 	sprintf(disk->disk_name, "sr%d", minor);
703 	disk->fops = &sr_bdops;
704 	disk->flags = GENHD_FL_CD | GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
705 	disk->events = DISK_EVENT_MEDIA_CHANGE | DISK_EVENT_EJECT_REQUEST;
706 
707 	blk_queue_rq_timeout(sdev->request_queue, SR_TIMEOUT);
708 
709 	cd->device = sdev;
710 	cd->disk = disk;
711 	cd->driver = &sr_template;
712 	cd->disk = disk;
713 	cd->capacity = 0x1fffff;
714 	cd->device->changed = 1;	/* force recheck CD type */
715 	cd->media_present = 1;
716 	cd->use = 1;
717 	cd->readcd_known = 0;
718 	cd->readcd_cdda = 0;
719 
720 	cd->cdi.ops = &sr_dops;
721 	cd->cdi.handle = cd;
722 	cd->cdi.mask = 0;
723 	cd->cdi.capacity = 1;
724 	sprintf(cd->cdi.name, "sr%d", minor);
725 
726 	sdev->sector_size = 2048;	/* A guess, just in case */
727 
728 	/* FIXME: need to handle a get_capabilities failure properly ?? */
729 	get_capabilities(cd);
730 	sr_vendor_init(cd);
731 
732 	set_capacity(disk, cd->capacity);
733 	disk->private_data = &cd->driver;
734 	disk->queue = sdev->request_queue;
735 	cd->cdi.disk = disk;
736 
737 	if (register_cdrom(&cd->cdi))
738 		goto fail_put;
739 
740 	/*
741 	 * Initialize block layer runtime PM stuffs before the
742 	 * periodic event checking request gets started in add_disk.
743 	 */
744 	blk_pm_runtime_init(sdev->request_queue, dev);
745 
746 	dev_set_drvdata(dev, cd);
747 	disk->flags |= GENHD_FL_REMOVABLE;
748 	device_add_disk(&sdev->sdev_gendev, disk);
749 
750 	sdev_printk(KERN_DEBUG, sdev,
751 		    "Attached scsi CD-ROM %s\n", cd->cdi.name);
752 	scsi_autopm_put_device(cd->device);
753 
754 	return 0;
755 
756 fail_put:
757 	put_disk(disk);
758 fail_free:
759 	kfree(cd);
760 fail:
761 	scsi_autopm_put_device(sdev);
762 	return error;
763 }
764 
765 
766 static void get_sectorsize(struct scsi_cd *cd)
767 {
768 	unsigned char cmd[10];
769 	unsigned char buffer[8];
770 	int the_result, retries = 3;
771 	int sector_size;
772 	struct request_queue *queue;
773 
774 	do {
775 		cmd[0] = READ_CAPACITY;
776 		memset((void *) &cmd[1], 0, 9);
777 		memset(buffer, 0, sizeof(buffer));
778 
779 		/* Do the command and wait.. */
780 		the_result = scsi_execute_req(cd->device, cmd, DMA_FROM_DEVICE,
781 					      buffer, sizeof(buffer), NULL,
782 					      SR_TIMEOUT, MAX_RETRIES, NULL);
783 
784 		retries--;
785 
786 	} while (the_result && retries);
787 
788 
789 	if (the_result) {
790 		cd->capacity = 0x1fffff;
791 		sector_size = 2048;	/* A guess, just in case */
792 	} else {
793 		long last_written;
794 
795 		cd->capacity = 1 + ((buffer[0] << 24) | (buffer[1] << 16) |
796 				    (buffer[2] << 8) | buffer[3]);
797 		/*
798 		 * READ_CAPACITY doesn't return the correct size on
799 		 * certain UDF media.  If last_written is larger, use
800 		 * it instead.
801 		 *
802 		 * http://bugzilla.kernel.org/show_bug.cgi?id=9668
803 		 */
804 		if (!cdrom_get_last_written(&cd->cdi, &last_written))
805 			cd->capacity = max_t(long, cd->capacity, last_written);
806 
807 		sector_size = (buffer[4] << 24) |
808 		    (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
809 		switch (sector_size) {
810 			/*
811 			 * HP 4020i CD-Recorder reports 2340 byte sectors
812 			 * Philips CD-Writers report 2352 byte sectors
813 			 *
814 			 * Use 2k sectors for them..
815 			 */
816 		case 0:
817 		case 2340:
818 		case 2352:
819 			sector_size = 2048;
820 			/* fall through */
821 		case 2048:
822 			cd->capacity *= 4;
823 			/* fall through */
824 		case 512:
825 			break;
826 		default:
827 			sr_printk(KERN_INFO, cd,
828 				  "unsupported sector size %d.", sector_size);
829 			cd->capacity = 0;
830 		}
831 
832 		cd->device->sector_size = sector_size;
833 
834 		/*
835 		 * Add this so that we have the ability to correctly gauge
836 		 * what the device is capable of.
837 		 */
838 		set_capacity(cd->disk, cd->capacity);
839 	}
840 
841 	queue = cd->device->request_queue;
842 	blk_queue_logical_block_size(queue, sector_size);
843 
844 	return;
845 }
846 
847 static void get_capabilities(struct scsi_cd *cd)
848 {
849 	unsigned char *buffer;
850 	struct scsi_mode_data data;
851 	struct scsi_sense_hdr sshdr;
852 	unsigned int ms_len = 128;
853 	int rc, n;
854 
855 	static const char *loadmech[] =
856 	{
857 		"caddy",
858 		"tray",
859 		"pop-up",
860 		"",
861 		"changer",
862 		"cartridge changer",
863 		"",
864 		""
865 	};
866 
867 
868 	/* allocate transfer buffer */
869 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
870 	if (!buffer) {
871 		sr_printk(KERN_ERR, cd, "out of memory.\n");
872 		return;
873 	}
874 
875 	/* eat unit attentions */
876 	scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
877 
878 	/* ask for mode page 0x2a */
879 	rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, ms_len,
880 			     SR_TIMEOUT, 3, &data, NULL);
881 
882 	if (!scsi_status_is_good(rc) || data.length > ms_len ||
883 	    data.header_length + data.block_descriptor_length > data.length) {
884 		/* failed, drive doesn't have capabilities mode page */
885 		cd->cdi.speed = 1;
886 		cd->cdi.mask |= (CDC_CD_R | CDC_CD_RW | CDC_DVD_R |
887 				 CDC_DVD | CDC_DVD_RAM |
888 				 CDC_SELECT_DISC | CDC_SELECT_SPEED |
889 				 CDC_MRW | CDC_MRW_W | CDC_RAM);
890 		kfree(buffer);
891 		sr_printk(KERN_INFO, cd, "scsi-1 drive");
892 		return;
893 	}
894 
895 	n = data.header_length + data.block_descriptor_length;
896 	cd->cdi.speed = ((buffer[n + 8] << 8) + buffer[n + 9]) / 176;
897 	cd->readcd_known = 1;
898 	cd->readcd_cdda = buffer[n + 5] & 0x01;
899 	/* print some capability bits */
900 	sr_printk(KERN_INFO, cd,
901 		  "scsi3-mmc drive: %dx/%dx %s%s%s%s%s%s\n",
902 		  ((buffer[n + 14] << 8) + buffer[n + 15]) / 176,
903 		  cd->cdi.speed,
904 		  buffer[n + 3] & 0x01 ? "writer " : "", /* CD Writer */
905 		  buffer[n + 3] & 0x20 ? "dvd-ram " : "",
906 		  buffer[n + 2] & 0x02 ? "cd/rw " : "", /* can read rewriteable */
907 		  buffer[n + 4] & 0x20 ? "xa/form2 " : "",	/* can read xa/from2 */
908 		  buffer[n + 5] & 0x01 ? "cdda " : "", /* can read audio data */
909 		  loadmech[buffer[n + 6] >> 5]);
910 	if ((buffer[n + 6] >> 5) == 0)
911 		/* caddy drives can't close tray... */
912 		cd->cdi.mask |= CDC_CLOSE_TRAY;
913 	if ((buffer[n + 2] & 0x8) == 0)
914 		/* not a DVD drive */
915 		cd->cdi.mask |= CDC_DVD;
916 	if ((buffer[n + 3] & 0x20) == 0)
917 		/* can't write DVD-RAM media */
918 		cd->cdi.mask |= CDC_DVD_RAM;
919 	if ((buffer[n + 3] & 0x10) == 0)
920 		/* can't write DVD-R media */
921 		cd->cdi.mask |= CDC_DVD_R;
922 	if ((buffer[n + 3] & 0x2) == 0)
923 		/* can't write CD-RW media */
924 		cd->cdi.mask |= CDC_CD_RW;
925 	if ((buffer[n + 3] & 0x1) == 0)
926 		/* can't write CD-R media */
927 		cd->cdi.mask |= CDC_CD_R;
928 	if ((buffer[n + 6] & 0x8) == 0)
929 		/* can't eject */
930 		cd->cdi.mask |= CDC_OPEN_TRAY;
931 
932 	if ((buffer[n + 6] >> 5) == mechtype_individual_changer ||
933 	    (buffer[n + 6] >> 5) == mechtype_cartridge_changer)
934 		cd->cdi.capacity =
935 		    cdrom_number_of_slots(&cd->cdi);
936 	if (cd->cdi.capacity <= 1)
937 		/* not a changer */
938 		cd->cdi.mask |= CDC_SELECT_DISC;
939 	/*else    I don't think it can close its tray
940 		cd->cdi.mask |= CDC_CLOSE_TRAY; */
941 
942 	/*
943 	 * if DVD-RAM, MRW-W or CD-RW, we are randomly writable
944 	 */
945 	if ((cd->cdi.mask & (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) !=
946 			(CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) {
947 		cd->writeable = 1;
948 	}
949 
950 	kfree(buffer);
951 }
952 
953 /*
954  * sr_packet() is the entry point for the generic commands generated
955  * by the Uniform CD-ROM layer.
956  */
957 static int sr_packet(struct cdrom_device_info *cdi,
958 		struct packet_command *cgc)
959 {
960 	struct scsi_cd *cd = cdi->handle;
961 	struct scsi_device *sdev = cd->device;
962 
963 	if (cgc->cmd[0] == GPCMD_READ_DISC_INFO && sdev->no_read_disc_info)
964 		return -EDRIVE_CANT_DO_THIS;
965 
966 	if (cgc->timeout <= 0)
967 		cgc->timeout = IOCTL_TIMEOUT;
968 
969 	sr_do_ioctl(cd, cgc);
970 
971 	return cgc->stat;
972 }
973 
974 /**
975  *	sr_kref_release - Called to free the scsi_cd structure
976  *	@kref: pointer to embedded kref
977  *
978  *	sr_ref_mutex must be held entering this routine.  Because it is
979  *	called on last put, you should always use the scsi_cd_get()
980  *	scsi_cd_put() helpers which manipulate the semaphore directly
981  *	and never do a direct kref_put().
982  **/
983 static void sr_kref_release(struct kref *kref)
984 {
985 	struct scsi_cd *cd = container_of(kref, struct scsi_cd, kref);
986 	struct gendisk *disk = cd->disk;
987 
988 	spin_lock(&sr_index_lock);
989 	clear_bit(MINOR(disk_devt(disk)), sr_index_bits);
990 	spin_unlock(&sr_index_lock);
991 
992 	unregister_cdrom(&cd->cdi);
993 
994 	disk->private_data = NULL;
995 
996 	put_disk(disk);
997 
998 	kfree(cd);
999 }
1000 
1001 static int sr_remove(struct device *dev)
1002 {
1003 	struct scsi_cd *cd = dev_get_drvdata(dev);
1004 
1005 	scsi_autopm_get_device(cd->device);
1006 
1007 	del_gendisk(cd->disk);
1008 	dev_set_drvdata(dev, NULL);
1009 
1010 	mutex_lock(&sr_ref_mutex);
1011 	kref_put(&cd->kref, sr_kref_release);
1012 	mutex_unlock(&sr_ref_mutex);
1013 
1014 	return 0;
1015 }
1016 
1017 static int __init init_sr(void)
1018 {
1019 	int rc;
1020 
1021 	rc = register_blkdev(SCSI_CDROM_MAJOR, "sr");
1022 	if (rc)
1023 		return rc;
1024 	rc = scsi_register_driver(&sr_template.gendrv);
1025 	if (rc)
1026 		unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
1027 
1028 	return rc;
1029 }
1030 
1031 static void __exit exit_sr(void)
1032 {
1033 	scsi_unregister_driver(&sr_template.gendrv);
1034 	unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
1035 }
1036 
1037 module_init(init_sr);
1038 module_exit(exit_sr);
1039 MODULE_LICENSE("GPL");
1040