path: root/drivers/scsi/sr.c

/*
 *  sr.c Copyright (C) 1992 David Giller
 *           Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
 *
 *  adapted from:
 *      sd.c Copyright (C) 1992 Drew Eckhardt
 *      Linux scsi disk driver by
 *              Drew Eckhardt <drew@colorado.edu>
 *
 *	Modified by Eric Youngdale ericy@andante.org to
 *	add scatter-gather, multiple outstanding request, and other
 *	enhancements.
 *
 *      Modified by Eric Youngdale eric@andante.org to support loadable
 *      low-level scsi drivers.
 *
 *      Modified by Thomas Quinot thomas@melchior.cuivre.fdn.fr to
 *      provide auto-eject.
 *
 *      Modified by Gerd Knorr <kraxel@cs.tu-berlin.de> to support the
 *      generic cdrom interface
 *
 *      Modified by Jens Axboe <axboe@suse.de> - Uniform sr_packet()
 *      interface, capabilities probe additions, ioctl cleanups, etc.
 *
 *	Modified by Richard Gooch <rgooch@atnf.csiro.au> to support devfs
 *
 *	Modified by Jens Axboe <axboe@suse.de> - support DVD-RAM
 *	transparently and lose the GHOST hack
 *
 *	Modified by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *	check resource allocation in sr_init and some cleanups
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/bio.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/cdrom.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <asm/uaccess.h>

#include <scsi/scsi.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_driver.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_ioctl.h>	/* For the door lock/unlock commands */

#include "scsi_logging.h"
#include "sr.h"


MODULE_DESCRIPTION("SCSI cdrom (sr) driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_CDROM_MAJOR);
MODULE_ALIAS_SCSI_DEVICE(TYPE_ROM);
MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);

#define SR_DISKS	256

#define SR_CAPABILITIES \
	(CDC_CLOSE_TRAY|CDC_OPEN_TRAY|CDC_LOCK|CDC_SELECT_SPEED| \
	 CDC_SELECT_DISC|CDC_MULTI_SESSION|CDC_MCN|CDC_MEDIA_CHANGED| \
	 CDC_PLAY_AUDIO|CDC_RESET|CDC_DRIVE_STATUS| \
	 CDC_CD_R|CDC_CD_RW|CDC_DVD|CDC_DVD_R|CDC_DVD_RAM|CDC_GENERIC_PACKET| \
	 CDC_MRW|CDC_MRW_W|CDC_RAM)

static DEFINE_MUTEX(sr_mutex);
static int sr_probe(struct device *);
static int sr_remove(struct device *);
static int sr_done(struct scsi_cmnd *);

static struct scsi_driver sr_template = {
	.owner			= THIS_MODULE,
	.gendrv = {
		.name   	= "sr",
		.probe		= sr_probe,
		.remove		= sr_remove,
	},
	.done			= sr_done,
};

static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
static DEFINE_SPINLOCK(sr_index_lock);

/* This semaphore is used to mediate the 0->1 reference get in the
 * face of object destruction (i.e. we can't allow a get on an
 * object after last put) */
static DEFINE_MUTEX(sr_ref_mutex);

static int sr_open(struct cdrom_device_info *, int);
static void sr_release(struct cdrom_device_info *);

static void get_sectorsize(struct scsi_cd *);
static void get_capabilities(struct scsi_cd *);

static unsigned int sr_check_events(struct cdrom_device_info *cdi,
				    unsigned int clearing, int slot);
static int sr_packet(struct cdrom_device_info *, struct packet_command *);

static struct cdrom_device_ops sr_dops = {
	.open			= sr_open,
	.release	 	= sr_release,
	.drive_status	 	= sr_drive_status,
	.check_events		= sr_check_events,
	.tray_move		= sr_tray_move,
	.lock_door		= sr_lock_door,
	.select_speed		= sr_select_speed,
	.get_last_session	= sr_get_last_session,
	.get_mcn		= sr_get_mcn,
	.reset			= sr_reset,
	.audio_ioctl		= sr_audio_ioctl,
	.capability		= SR_CAPABILITIES,
	.generic_packet		= sr_packet,
};

static void sr_kref_release(struct kref *kref);

static inline struct scsi_cd *scsi_cd(struct gendisk *disk)
{
	return container_of(disk->private_data, struct scsi_cd, driver);
}

/*
 * The get and put routines for the struct scsi_cd.  Note this entity
 * has a scsi_device pointer and owns a reference to this.
 */
static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk)
{
	struct scsi_cd *cd = NULL;

	mutex_lock(&sr_ref_mutex);
	if (disk->private_data == NULL)
		goto out;
	cd = scsi_cd(disk);
	kref_get(&cd->kref);
	if (scsi_device_get(cd->device))
		goto out_put;
	goto out;

 out_put:
	kref_put(&cd->kref, sr_kref_release);
	cd = NULL;
 out:
	mutex_unlock(&sr_ref_mutex);
	return cd;
}

static void scsi_cd_put(struct scsi_cd *cd)
{
	struct scsi_device *sdev = cd->device;

	mutex_lock(&sr_ref_mutex);
	kref_put(&cd->kref, sr_kref_release);
	scsi_device_put(sdev);
	mutex_unlock(&sr_ref_mutex);
}

static unsigned int sr_get_events(struct scsi_device *sdev)
{
	u8 buf[8];
	u8 cmd[] = { GET_EVENT_STATUS_NOTIFICATION,
		     1,			/* polled */
		     0, 0,		/* reserved */
		     1 << 4,		/* notification class: media */
		     0, 0,		/* reserved */
		     0, sizeof(buf),	/* allocation length */
		     0,			/* control */
	};
	struct event_header