pktcdvd.c

Linux块设备驱动源码

		printk("pktcdvd: Can't write to last track (reserved)\n");
		return 1;
	}

	return 0;
}

static int pkt_probe_settings(struct pktcdvd_device *pd)
{
	struct packet_command cgc;
	unsigned char buf[12];
	disc_information di;
	track_information ti;
	int ret, track;

	init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_READ);
	cgc.cmd[0] = GPCMD_GET_CONFIGURATION;
	cgc.cmd[8] = 8;
	ret = pkt_generic_packet(pd, &cgc);
	pd->mmc3_profile = ret ? 0xffff : buf[6] << 8 | buf[7];

	memset(&di, 0, sizeof(disc_information));
	memset(&ti, 0, sizeof(track_information));

	if ((ret = pkt_get_disc_info(pd, &di))) {
		printk("failed get_disc\n");
		return ret;
	}

	if (pkt_good_disc(pd, &di))
		return -ENXIO;

	switch (pd->mmc3_profile) {
		case 0x1a: /* DVD+RW */
			printk("pktcdvd: inserted media is DVD+RW\n");
			break;
		case 0x13: /* DVD-RW */
			printk("pktcdvd: inserted media is DVD-RW\n");
			break;
		case 0x12: /* DVD-RAM */
			printk("pktcdvd: inserted media is DVD-RAM\n");
			break;
		default:
			printk("pktcdvd: inserted media is CD-R%s\n", di.erasable ? "W" : "");
			break;
	}
	pd->type = di.erasable ? PACKET_CDRW : PACKET_CDR;

	track = 1; /* (di.last_track_msb << 8) | di.last_track_lsb; */
	if ((ret = pkt_get_track_info(pd, track, 1, &ti))) {
		printk("pktcdvd: failed get_track\n");
		return ret;
	}

	if (pkt_good_track(&ti)) {
		printk("pktcdvd: can't write to this track\n");
		return -ENXIO;
	}

	/*
	 * we keep packet size in 512 byte units, makes it easier to
	 * deal with request calculations.
	 */
	pd->settings.size = be32_to_cpu(ti.fixed_packet_size) << 2;
	if (pd->settings.size == 0) {
		printk("pktcdvd: detected zero packet size!\n");
		pd->settings.size = 128;
	}
	if (pd->settings.size > PACKET_MAX_SECTORS) {
		printk("pktcdvd: packet size is too big\n");
		return -ENXIO;
	}
	pd->settings.fp = ti.fp;
	pd->offset = (be32_to_cpu(ti.track_start) << 2) & (pd->settings.size - 1);

	if (ti.nwa_v) {
		pd->nwa = be32_to_cpu(ti.next_writable);
		set_bit(PACKET_NWA_VALID, &pd->flags);
	}

	/*
	 * in theory we could use lra on -RW media as well and just zero
	 * blocks that haven't been written yet, but in practice that
	 * is just a no-go. we'll use that for -R, naturally.
	 */
	if (ti.lra_v) {
		pd->lra = be32_to_cpu(ti.last_rec_address);
		set_bit(PACKET_LRA_VALID, &pd->flags);
	} else {
		pd->lra = 0xffffffff;
		set_bit(PACKET_LRA_VALID, &pd->flags);
	}

	/*
	 * fine for now
	 */
	pd->settings.link_loss = 7;
	pd->settings.write_type = 0;	/* packet */
	pd->settings.track_mode = ti.track_mode;

	/*
	 * mode1 or mode2 disc
	 */
	switch (ti.data_mode) {
		case PACKET_MODE1:
			pd->settings.block_mode = PACKET_BLOCK_MODE1;
			break;
		case PACKET_MODE2:
			pd->settings.block_mode = PACKET_BLOCK_MODE2;
			break;
		default:
			printk("pktcdvd: unknown data mode\n");
			return 1;
	}
	return 0;
}

/*
 * enable/disable write caching on drive
 */
static int pkt_write_caching(struct pktcdvd_device *pd, int set)
{
	struct packet_command cgc;
	struct request_sense sense;
	unsigned char buf[64];
	int ret;

	memset(buf, 0, sizeof(buf));
	init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_READ);
	cgc.sense = &sense;
	cgc.buflen = pd->mode_offset + 12;

	/*
	 * caching mode page might not be there, so quiet this command
	 */
	cgc.quiet = 1;

	if ((ret = pkt_mode_sense(pd, &cgc, GPMODE_WCACHING_PAGE, 0)))
		return ret;

	buf[pd->mode_offset + 10] |= (!!set << 2);

	cgc.buflen = cgc.cmd[8] = 2 + ((buf[0] << 8) | (buf[1] & 0xff));
	ret = pkt_mode_select(pd, &cgc);
	if (ret) {
		printk("pktcdvd: write caching control failed\n");
		pkt_dump_sense(&cgc);
	} else if (!ret && set)
		printk("pktcdvd: enabled write caching on %s\n", pd->name);
	return ret;
}

static int pkt_lock_door(struct pktcdvd_device *pd, int lockflag)
{
	struct packet_command cgc;

	init_cdrom_command(&cgc, NULL, 0, CGC_DATA_NONE);
	cgc.cmd[0] = GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL;
	cgc.cmd[4] = lockflag ? 1 : 0;
	return pkt_generic_packet(pd, &cgc);
}

/*
 * Returns drive maximum write speed
 */
static int pkt_get_max_speed(struct pktcdvd_device *pd, unsigned *write_speed)
{
	struct packet_command cgc;
	struct request_sense sense;
	unsigned char buf[256+18];
	unsigned char *cap_buf;
	int ret, offset;

	memset(buf, 0, sizeof(buf));
	cap_buf = &buf[sizeof(struct mode_page_header) + pd->mode_offset];
	init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_UNKNOWN);
	cgc.sense = &sense;

	ret = pkt_mode_sense(pd, &cgc, GPMODE_CAPABILITIES_PAGE, 0);
	if (ret) {
		cgc.buflen = pd->mode_offset + cap_buf[1] + 2 +
			     sizeof(struct mode_page_header);
		ret = pkt_mode_sense(pd, &cgc, GPMODE_CAPABILITIES_PAGE, 0);
		if (ret) {
			pkt_dump_sense(&cgc);
			return ret;
		}
	}

	offset = 20;			    /* Obsoleted field, used by older drives */
	if (cap_buf[1] >= 28)
		offset = 28;		    /* Current write speed selected */
	if (cap_buf[1] >= 30) {
		/* If the drive reports at least one "Logical Unit Write
		 * Speed Performance Descriptor Block", use the information
		 * in the first block. (contains the highest speed)
		 */
		int num_spdb = (cap_buf[30] << 8) + cap_buf[31];
		if (num_spdb > 0)
			offset = 34;
	}

	*write_speed = (cap_buf[offset] << 8) | cap_buf[offset + 1];
	return 0;
}

/* These tables from cdrecord - I don't have orange book */
/* standard speed CD-RW (1-4x) */
static char clv_to_speed[16] = {
	/* 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 */
	   0, 2, 4, 6, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
/* high speed CD-RW (-10x) */
static char hs_clv_to_speed[16] = {
	/* 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 */
	   0, 2, 4, 6, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
/* ultra high speed CD-RW */
static char us_clv_to_speed[16] = {
	/* 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 */
	   0, 2, 4, 8, 0, 0,16, 0,24,32,40,48, 0, 0, 0, 0
};

/*
 * reads the maximum media speed from ATIP
 */
static int pkt_media_speed(struct pktcdvd_device *pd, unsigned *speed)
{
	struct packet_command cgc;
	struct request_sense sense;
	unsigned char buf[64];
	unsigned int size, st, sp;
	int ret;

	init_cdrom_command(&cgc, buf, 2, CGC_DATA_READ);
	cgc.sense = &sense;
	cgc.cmd[0] = GPCMD_READ_TOC_PMA_ATIP;
	cgc.cmd[1] = 2;
	cgc.cmd[2] = 4; /* READ ATIP */
	cgc.cmd[8] = 2;
	ret = pkt_generic_packet(pd, &cgc);
	if (ret) {
		pkt_dump_sense(&cgc);
		return ret;
	}
	size = ((unsigned int) buf[0]<<8) + buf[1] + 2;
	if (size > sizeof(buf))
		size = sizeof(buf);

	init_cdrom_command(&cgc, buf, size, CGC_DATA_READ);
	cgc.sense = &sense;
	cgc.cmd[0] = GPCMD_READ_TOC_PMA_ATIP;
	cgc.cmd[1] = 2;
	cgc.cmd[2] = 4;
	cgc.cmd[8] = size;
	ret = pkt_generic_packet(pd, &cgc);
	if (ret) {
		pkt_dump_sense(&cgc);
		return ret;
	}

	if (!buf[6] & 0x40) {
		printk("pktcdvd: Disc type is not CD-RW\n");
		return 1;
	}
	if (!buf[6] & 0x4) {
		printk("pktcdvd: A1 values on media are not valid, maybe not CDRW?\n");
		return 1;
	}

	st = (buf[6] >> 3) & 0x7; /* disc sub-type */

	sp = buf[16] & 0xf; /* max speed from ATIP A1 field */

	/* Info from cdrecord */
	switch (st) {
		case 0: /* standard speed */
			*speed = clv_to_speed[sp];
			break;
		case 1: /* high speed */
			*speed = hs_clv_to_speed[sp];
			break;
		case 2: /* ultra high speed */
			*speed = us_clv_to_speed[sp];
			break;
		default:
			printk("pktcdvd: Unknown disc sub-type %d\n",st);
			return 1;
	}
	if (*speed) {
		printk("pktcdvd: Max. media speed: %d\n",*speed);
		return 0;
	} else {
		printk("pktcdvd: Unknown speed %d for sub-type %d\n",sp,st);
		return 1;
	}
}

static int pkt_perform_opc(struct pktcdvd_device *pd)
{
	struct packet_command cgc;
	struct request_sense sense;
	int ret;

	VPRINTK("pktcdvd: Performing OPC\n");

	init_cdrom_command(&cgc, NULL, 0, CGC_DATA_NONE);
	cgc.sense = &sense;
	cgc.timeout = 60*HZ;
	cgc.cmd[0] = GPCMD_SEND_OPC;
	cgc.cmd[1] = 1;
	if ((ret = pkt_generic_packet(pd, &cgc)))
		pkt_dump_sense(&cgc);
	return ret;
}

static int pkt_open_write(struct pktcdvd_device *pd)
{
	int ret;
	unsigned int write_speed, media_write_speed, read_speed;

	if ((ret = pkt_probe_settings(pd))) {
		DPRINTK("pktcdvd: %s failed probe\n", pd->name);
		return -EIO;
	}

	if ((ret = pkt_set_write_settings(pd))) {
		DPRINTK("pktcdvd: %s failed saving write settings\n", pd->name);
		return -EIO;
	}

	pkt_write_caching(pd, USE_WCACHING);

	if ((ret = pkt_get_max_speed(pd, &write_speed)))
		write_speed = 16 * 177;
	switch (pd->mmc3_profile) {
		case 0x13: /* DVD-RW */
		case 0x1a: /* DVD+RW */
		case 0x12: /* DVD-RAM */
			DPRINTK("pktcdvd: write speed %ukB/s\n", write_speed);
			break;
		default:
			if ((ret = pkt_media_speed(pd, &media_write_speed)))
				media_write_speed = 16;
			write_speed = min(write_speed, media_write_speed * 177);
			DPRINTK("pktcdvd: write speed %ux\n", write_speed / 176);
			break;
	}
	read_speed = write_speed;

	if ((ret = pkt_set_speed(pd, write_speed, read_speed))) {
		DPRINTK("pktcdvd: %s couldn't set write speed\n", pd->name);
		return -EIO;
	}
	pd->write_speed = write_speed;
	pd->read_speed = read_speed;

	if ((ret = pkt_perform_opc(pd))) {
		DPRINTK("pktcdvd: %s Optimum Power Calibration failed\n", pd->name);
	}

	return 0;
}

/*
 * called at open time.
 */
static int pkt_open_dev(struct pktcdvd_device *pd, int write)
{
	int ret;
	long lba;
	request_queue_t *q;

	/*
	 * We need to re-open the cdrom device without O_NONBLOCK to be able
	 * to read/write from/to it. It is already opened in O_NONBLOCK mode
	 * so bdget() can't fail.
	 */
	bdget(pd->bdev->bd_dev);
	if ((ret = blkdev_get(pd->bdev, FMODE_READ, O_RDONLY)))
		goto out;

	if ((ret = pkt_get_last_written(pd, &lba))) {
		printk("pktcdvd: pkt_get_last_written failed\n");
		goto out_putdev;
	}

	set_capacity(pd->disk, lba << 2);
	set_capacity(pd->bdev->bd_disk, lba << 2);
	bd_set_size(pd->bdev, (loff_t)lba << 11);

	q = bdev_get_queue(pd->bdev);
	if (write) {
		if ((ret = pkt_open_write(pd)))
			goto out_putdev;
		/*
		 * Some CDRW drives can not handle writes larger than one packet,
		 * even if the size is a multiple of the packet size.
		 */
		spin_lock_irq(q->queue_lock);
		blk_queue_max_sectors(q, pd->settings.size);
		spin_unlock_irq(q->queue_lock);
		set_bit(PACKET_WRITABLE, &pd->flags);
	} else {
		pkt_set_speed(pd, MAX_SPEED, MAX_SPEED);
		clear_bit(PACKET_WRITABLE, &pd->flags);
	}

	if ((ret = pkt_set_segment_merging(pd, q)))
		goto out_putdev;

	if (write)
		printk("pktcdvd: %lukB available on disc\n", lba << 1);

	return 0;

out_putdev:
	blkdev_put(pd->bdev);
out:
	return ret;
}

/*
 * called when the device is closed. makes sure that the device flushes
 * the internal cache before we close.
 */
static void pkt_release_dev(struct pktcdvd_device *pd, int flush)
{
	if (flush && pkt_flush_cache(pd))
		DPRINTK("pktcdvd: %s not flushing cache\n", pd->name);

	pkt_lock_door(pd, 0);

	pkt_set_speed(pd, MAX_SPEED, MAX_SPEED);
	blkdev_put(pd->bdev);
}

static struct pktcdvd_device *pkt_find_dev_from_minor(int dev_minor)
{
	if (dev_minor >= MAX_WRITERS)
		return NULL;
	return pkt_devs[dev_minor];
}

static int pkt_open(struct inode *inode, struct file *file)
{
	struct pktcdvd_device *pd = NULL;
	int ret;

	VPRINTK("pktcdvd: entering open\n");

	down(&ctl_mutex);
	pd = pkt_find_dev_from_minor(iminor(inode));
	if (!pd) {
		ret = -ENODEV;
		goto out;
	}
	BUG_ON(pd->refcnt < 0);

	pd->refcnt++;
	if (pd->refcnt > 1) {
		if ((file->f_mode & FMODE_WRITE) &&
		    !test_bit(PACKET_WRITABLE, &pd->flags)) {
			ret = -EBUSY;
			goto out_dec;
		}
	} else {
		if (pkt_open_dev(pd, file->f_mode & FMODE_WRITE)) {
			ret = -EIO;
			goto out_dec;
		}
		/*
		 * needed here as well, since ext2 (among others) may change
		 * the blocksize at mount time
		 */
		set_blocksize(inode->i_bdev, CD_FRAMESIZE);
	}

	up(&ctl_mutex);
	return 0;

out_dec:
	pd->refcnt--;
out:
	VPRINTK("pktcdvd: failed open (%d)\n", ret);
	up(&ctl_mutex);
	return ret;
}

static int pkt_close(struct inode *inode, struct file *file)
{
	struct pktcdvd_device *pd = inode->i_bdev->bd_disk->private_data;
	int ret = 0;

	down(&ctl_mutex);
	pd->refcnt--;
	BUG_ON(pd->refcnt < 0);
	if (pd->refcnt == 0) {
		int flush = test_bit(PACKET_WRITABLE, &pd->flags);
		pkt_release_dev(pd, flush);
	}
	up(&ctl_mutex);
	return ret;
}


static void *psd_pool_alloc(gfp_t gfp_mask, void *data)
{
	return kmalloc(sizeof(struct packet_stacked_data), gfp_mask);
}

static void psd_pool_free(void *ptr, void *data)
{
	kfree(ptr);
}

static int pkt_end_io_read_cloned(struct bio *bio, unsigned int bytes_done, int err)
{
	struct packet_stacked_data *psd = bio->bi_private;
	struct pktcdvd_device *pd = psd->pd;

	if (bio->bi_size)
		return 1;

	bio_put(bio);
	bio_endio(psd->bio, psd->bio->bi_size, err);