sr.c

linux 内核源代码

	scsi_cd_put(cd);

	return 0;
}

static int sr_block_ioctl(struct inode *inode, struct file *file, unsigned cmd,
			  unsigned long arg)
{
	struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
	struct scsi_device *sdev = cd->device;
	void __user *argp = (void __user *)arg;
	int ret;

	/*
	 * Send SCSI addressing ioctls directly to mid level, send other
	 * ioctls to cdrom/block level.
	 */
	switch (cmd) {
	case SCSI_IOCTL_GET_IDLUN:
	case SCSI_IOCTL_GET_BUS_NUMBER:
		return scsi_ioctl(sdev, cmd, argp);
	}

	ret = cdrom_ioctl(file, &cd->cdi, inode, cmd, arg);
	if (ret != -ENOSYS)
		return ret;

	/*
	 * ENODEV means that we didn't recognise the ioctl, or that we
	 * cannot execute it in the current device state.  In either
	 * case fall through to scsi_ioctl, which will return ENDOEV again
	 * if it doesn't recognise the ioctl
	 */
	ret = scsi_nonblockable_ioctl(sdev, cmd, argp, NULL);
	if (ret != -ENODEV)
		return ret;
	return scsi_ioctl(sdev, cmd, argp);
}

static int sr_block_media_changed(struct gendisk *disk)
{
	struct scsi_cd *cd = scsi_cd(disk);
	return cdrom_media_changed(&cd->cdi);
}

static struct block_device_operations sr_bdops =
{
	.owner		= THIS_MODULE,
	.open		= sr_block_open,
	.release	= sr_block_release,
	.ioctl		= sr_block_ioctl,
	.media_changed	= sr_block_media_changed,
	/* 
	 * No compat_ioctl for now because sr_block_ioctl never
	 * seems to pass arbitary ioctls down to host drivers.
	 */
};

static int sr_open(struct cdrom_device_info *cdi, int purpose)
{
	struct scsi_cd *cd = cdi->handle;
	struct scsi_device *sdev = cd->device;
	int retval;

	/*
	 * If the device is in error recovery, wait until it is done.
	 * If the device is offline, then disallow any access to it.
	 */
	retval = -ENXIO;
	if (!scsi_block_when_processing_errors(sdev))
		goto error_out;

	return 0;

error_out:
	return retval;	
}

static void sr_release(struct cdrom_device_info *cdi)
{
	struct scsi_cd *cd = cdi->handle;

	if (cd->device->sector_size > 2048)
		sr_set_blocklength(cd, 2048);

}

static int sr_probe(struct device *dev)
{
	struct scsi_device *sdev = to_scsi_device(dev);
	struct gendisk *disk;
	struct scsi_cd *cd;
	int minor, error;

	error = -ENODEV;
	if (sdev->type != TYPE_ROM && sdev->type != TYPE_WORM)
		goto fail;

	error = -ENOMEM;
	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
	if (!cd)
		goto fail;

	kref_init(&cd->kref);

	disk = alloc_disk(1);
	if (!disk)
		goto fail_free;

	spin_lock(&sr_index_lock);
	minor = find_first_zero_bit(sr_index_bits, SR_DISKS);
	if (minor == SR_DISKS) {
		spin_unlock(&sr_index_lock);
		error = -EBUSY;
		goto fail_put;
	}
	__set_bit(minor, sr_index_bits);
	spin_unlock(&sr_index_lock);

	disk->major = SCSI_CDROM_MAJOR;
	disk->first_minor = minor;
	sprintf(disk->disk_name, "sr%d", minor);
	disk->fops = &sr_bdops;
	disk->flags = GENHD_FL_CD;

	cd->device = sdev;
	cd->disk = disk;
	cd->driver = &sr_template;
	cd->disk = disk;
	cd->capacity = 0x1fffff;
	cd->device->changed = 1;	/* force recheck CD type */
	cd->use = 1;
	cd->readcd_known = 0;
	cd->readcd_cdda = 0;

	cd->cdi.ops = &sr_dops;
	cd->cdi.handle = cd;
	cd->cdi.mask = 0;
	cd->cdi.capacity = 1;
	sprintf(cd->cdi.name, "sr%d", minor);

	sdev->sector_size = 2048;	/* A guess, just in case */

	/* FIXME: need to handle a get_capabilities failure properly ?? */
	get_capabilities(cd);
	blk_queue_prep_rq(sdev->request_queue, sr_prep_fn);
	sr_vendor_init(cd);

	disk->driverfs_dev = &sdev->sdev_gendev;
	set_capacity(disk, cd->capacity);
	disk->private_data = &cd->driver;
	disk->queue = sdev->request_queue;
	cd->cdi.disk = disk;

	if (register_cdrom(&cd->cdi))
		goto fail_put;

	dev_set_drvdata(dev, cd);
	disk->flags |= GENHD_FL_REMOVABLE;
	add_disk(disk);

	sdev_printk(KERN_DEBUG, sdev,
		    "Attached scsi CD-ROM %s\n", cd->cdi.name);
	return 0;

fail_put:
	put_disk(disk);
fail_free:
	kfree(cd);
fail:
	return error;
}


static void get_sectorsize(struct scsi_cd *cd)
{
	unsigned char cmd[10];
	unsigned char *buffer;
	int the_result, retries = 3;
	int sector_size;
	struct request_queue *queue;

	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
	if (!buffer)
		goto Enomem;

	do {
		cmd[0] = READ_CAPACITY;
		memset((void *) &cmd[1], 0, 9);
		memset(buffer, 0, 8);

		/* Do the command and wait.. */
		the_result = scsi_execute_req(cd->device, cmd, DMA_FROM_DEVICE,
					      buffer, 8, NULL, SR_TIMEOUT,
					      MAX_RETRIES);

		retries--;

	} while (the_result && retries);


	if (the_result) {
		cd->capacity = 0x1fffff;
		sector_size = 2048;	/* A guess, just in case */
	} else {
#if 0
		if (cdrom_get_last_written(&cd->cdi,
					   &cd->capacity))
#endif
			cd->capacity = 1 + ((buffer[0] << 24) |
						    (buffer[1] << 16) |
						    (buffer[2] << 8) |
						    buffer[3]);
		sector_size = (buffer[4] << 24) |
		    (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
		switch (sector_size) {
			/*
			 * HP 4020i CD-Recorder reports 2340 byte sectors
			 * Philips CD-Writers report 2352 byte sectors
			 *
			 * Use 2k sectors for them..
			 */
		case 0:
		case 2340:
		case 2352:
			sector_size = 2048;
			/* fall through */
		case 2048:
			cd->capacity *= 4;
			/* fall through */
		case 512:
			break;
		default:
			printk("%s: unsupported sector size %d.\n",
			       cd->cdi.name, sector_size);
			cd->capacity = 0;
		}

		cd->device->sector_size = sector_size;

		/*
		 * Add this so that we have the ability to correctly gauge
		 * what the device is capable of.
		 */
		set_capacity(cd->disk, cd->capacity);
	}

	queue = cd->device->request_queue;
	blk_queue_hardsect_size(queue, sector_size);
out:
	kfree(buffer);
	return;

Enomem:
	cd->capacity = 0x1fffff;
	cd->device->sector_size = 2048;	/* A guess, just in case */
	goto out;
}

static void get_capabilities(struct scsi_cd *cd)
{
	unsigned char *buffer;
	struct scsi_mode_data data;
	unsigned char cmd[MAX_COMMAND_SIZE];
	struct scsi_sense_hdr sshdr;
	unsigned int the_result;
	int retries, rc, n;

	static const char *loadmech[] =
	{
		"caddy",
		"tray",
		"pop-up",
		"",
		"changer",
		"cartridge changer",
		"",
		""
	};


	/* allocate transfer buffer */
	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
	if (!buffer) {
		printk(KERN_ERR "sr: out of memory.\n");
		return;
	}

	/* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
	 * conditions are gone, or a timeout happens
	 */
	retries = 0;
	do {
		memset((void *)cmd, 0, MAX_COMMAND_SIZE);
		cmd[0] = TEST_UNIT_READY;

		the_result = scsi_execute_req (cd->device, cmd, DMA_NONE, NULL,
					       0, &sshdr, SR_TIMEOUT,
					       MAX_RETRIES);

		retries++;
	} while (retries < 5 && 
		 (!scsi_status_is_good(the_result) ||
		  (scsi_sense_valid(&sshdr) &&
		   sshdr.sense_key == UNIT_ATTENTION)));

	/* ask for mode page 0x2a */
	rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128,
			     SR_TIMEOUT, 3, &data, NULL);

	if (!scsi_status_is_good(rc)) {
		/* failed, drive doesn't have capabilities mode page */
		cd->cdi.speed = 1;
		cd->cdi.mask |= (CDC_CD_R | CDC_CD_RW | CDC_DVD_R |
				 CDC_DVD | CDC_DVD_RAM |
				 CDC_SELECT_DISC | CDC_SELECT_SPEED |
				 CDC_MRW | CDC_MRW_W | CDC_RAM);
		kfree(buffer);
		printk("%s: scsi-1 drive\n", cd->cdi.name);
		return;
	}

	n = data.header_length + data.block_descriptor_length;
	cd->cdi.speed = ((buffer[n + 8] << 8) + buffer[n + 9]) / 176;
	cd->readcd_known = 1;
	cd->readcd_cdda = buffer[n + 5] & 0x01;
	/* print some capability bits */
	printk("%s: scsi3-mmc drive: %dx/%dx %s%s%s%s%s%s\n", cd->cdi.name,
	       ((buffer[n + 14] << 8) + buffer[n + 15]) / 176,
	       cd->cdi.speed,
	       buffer[n + 3] & 0x01 ? "writer " : "", /* CD Writer */
	       buffer[n + 3] & 0x20 ? "dvd-ram " : "",
	       buffer[n + 2] & 0x02 ? "cd/rw " : "", /* can read rewriteable */
	       buffer[n + 4] & 0x20 ? "xa/form2 " : "",	/* can read xa/from2 */
	       buffer[n + 5] & 0x01 ? "cdda " : "", /* can read audio data */
	       loadmech[buffer[n + 6] >> 5]);
	if ((buffer[n + 6] >> 5) == 0)
		/* caddy drives can't close tray... */
		cd->cdi.mask |= CDC_CLOSE_TRAY;
	if ((buffer[n + 2] & 0x8) == 0)
		/* not a DVD drive */
		cd->cdi.mask |= CDC_DVD;
	if ((buffer[n + 3] & 0x20) == 0) 
		/* can't write DVD-RAM media */
		cd->cdi.mask |= CDC_DVD_RAM;
	if ((buffer[n + 3] & 0x10) == 0)
		/* can't write DVD-R media */
		cd->cdi.mask |= CDC_DVD_R;
	if ((buffer[n + 3] & 0x2) == 0)
		/* can't write CD-RW media */
		cd->cdi.mask |= CDC_CD_RW;
	if ((buffer[n + 3] & 0x1) == 0)
		/* can't write CD-R media */
		cd->cdi.mask |= CDC_CD_R;
	if ((buffer[n + 6] & 0x8) == 0)
		/* can't eject */
		cd->cdi.mask |= CDC_OPEN_TRAY;

	if ((buffer[n + 6] >> 5) == mechtype_individual_changer ||
	    (buffer[n + 6] >> 5) == mechtype_cartridge_changer)
		cd->cdi.capacity =
		    cdrom_number_of_slots(&cd->cdi);
	if (cd->cdi.capacity <= 1)
		/* not a changer */
		cd->cdi.mask |= CDC_SELECT_DISC;
	/*else    I don't think it can close its tray
		cd->cdi.mask |= CDC_CLOSE_TRAY; */

	/*
	 * if DVD-RAM, MRW-W or CD-RW, we are randomly writable
	 */
	if ((cd->cdi.mask & (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) !=
			(CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) {
		cd->device->writeable = 1;
	}

	kfree(buffer);
}

/*
 * sr_packet() is the entry point for the generic commands generated
 * by the Uniform CD-ROM layer. 
 */
static int sr_packet(struct cdrom_device_info *cdi,
		struct packet_command *cgc)
{
	if (cgc->timeout <= 0)
		cgc->timeout = IOCTL_TIMEOUT;

	sr_do_ioctl(cdi->handle, cgc);

	return cgc->stat;
}

/**
 *	sr_kref_release - Called to free the scsi_cd structure
 *	@kref: pointer to embedded kref
 *
 *	sr_ref_mutex must be held entering this routine.  Because it is
 *	called on last put, you should always use the scsi_cd_get()
 *	scsi_cd_put() helpers which manipulate the semaphore directly
 *	and never do a direct kref_put().
 **/
static void sr_kref_release(struct kref *kref)
{
	struct scsi_cd *cd = container_of(kref, struct scsi_cd, kref);
	struct gendisk *disk = cd->disk;

	spin_lock(&sr_index_lock);
	clear_bit(disk->first_minor, sr_index_bits);
	spin_unlock(&sr_index_lock);

	unregister_cdrom(&cd->cdi);

	disk->private_data = NULL;

	put_disk(disk);

	kfree(cd);
}

static int sr_remove(struct device *dev)
{
	struct scsi_cd *cd = dev_get_drvdata(dev);

	del_gendisk(cd->disk);

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

	return 0;
}

static int __init init_sr(void)
{
	int rc;

	rc = register_blkdev(SCSI_CDROM_MAJOR, "sr");
	if (rc)
		return rc;
	rc = scsi_register_driver(&sr_template.gendrv);
	if (rc)
		unregister_blkdev(SCSI_CDROM_MAJOR, "sr");

	return rc;
}

static void __exit exit_sr(void)
{
	scsi_unregister_driver(&sr_template.gendrv);
	unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
}

module_init(init_sr);
module_exit(exit_sr);
MODULE_LICENSE("GPL");