drivers/block/sunvdc.c - kernel/msm-4.19 - Gitiles

 /* sunvdc.c: Sun LDOM Virtual Disk Client.
  *
  * Copyright (C) 2007, 2008 David S. Miller <davem@davemloft.net>
  */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/blkdev.h>
 #include <linux/hdreg.h>
 #include <linux/genhd.h>
 #include <linux/cdrom.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/scatterlist.h>

 #include <asm/vio.h>
 #include <asm/ldc.h>

 #define DRV_MODULE_NAME		"sunvdc"
 #define PFX DRV_MODULE_NAME	": "
 #define DRV_MODULE_VERSION	"1.1"
 #define DRV_MODULE_RELDATE	"February 13, 2013"

 static char version[] =
 	DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";
 MODULE_AUTHOR("David S. Miller (davem@davemloft.net)");
 MODULE_DESCRIPTION("Sun LDOM virtual disk client driver");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(DRV_MODULE_VERSION);

 #define VDC_TX_RING_SIZE	256

 #define WAITING_FOR_LINK_UP	0x01
 #define WAITING_FOR_TX_SPACE	0x02
 #define WAITING_FOR_GEN_CMD	0x04
 #define WAITING_FOR_ANY		-1

 struct vdc_req_entry {
 	struct request		*req;
 };

 struct vdc_port {
 	struct vio_driver_state	vio;

 	struct gendisk		*disk;

 	struct vdc_completion	*cmp;

 	u64			req_id;
 	u64			seq;
 	struct vdc_req_entry	rq_arr[VDC_TX_RING_SIZE];

 	unsigned long		ring_cookies;

 	u64			max_xfer_size;
 	u32			vdisk_block_size;

 	/* The server fills these in for us in the disk attribute
 	 * ACK packet.
 	 */
 	u64			operations;
 	u32			vdisk_size;
 	u8			vdisk_type;
 	u8			vdisk_mtype;

 	char			disk_name[32];

 	struct vio_disk_geom	geom;
 	struct vio_disk_vtoc	label;
 };

 static inline struct vdc_port *to_vdc_port(struct vio_driver_state *vio)
 {
 	return container_of(vio, struct vdc_port, vio);
 }

 /* Ordered from largest major to lowest */
 static struct vio_version vdc_versions[] = {
 	{ .major = 1, .minor = 1 },
 	{ .major = 1, .minor = 0 },
 };

 static inline int vdc_version_supported(struct vdc_port *port,
 					u16 major, u16 minor)
 {
 	return port->vio.ver.major == major && port->vio.ver.minor >= minor;
 }

 #define VDCBLK_NAME	"vdisk"
 static int vdc_major;
 #define PARTITION_SHIFT	3

 static inline u32 vdc_tx_dring_avail(struct vio_dring_state *dr)
 {
 	return vio_dring_avail(dr, VDC_TX_RING_SIZE);
 }

 static int vdc_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 {
 	struct gendisk *disk = bdev->bd_disk;
 	struct vdc_port *port = disk->private_data;

 	geo->heads = (u8) port->geom.num_hd;
 	geo->sectors = (u8) port->geom.num_sec;
 	geo->cylinders = port->geom.num_cyl;

 	return 0;
 }

 /* Add ioctl/CDROM_GET_CAPABILITY to support cdrom_id in udev
  * when vdisk_mtype is VD_MEDIA_TYPE_CD or VD_MEDIA_TYPE_DVD.
  * Needed to be able to install inside an ldom from an iso image.
  */
 static int vdc_ioctl(struct block_device *bdev, fmode_t mode,
 		     unsigned command, unsigned long argument)
 {
 	int i;
 	struct gendisk *disk;

 	switch (command) {
 	case CDROMMULTISESSION:
 		pr_debug(PFX "Multisession CDs not supported\n");
 		for (i = 0; i < sizeof(struct cdrom_multisession); i++)
 			if (put_user(0, (char __user *)(argument + i)))
 				return -EFAULT;
 		return 0;

 	case CDROM_GET_CAPABILITY:
 		disk = bdev->bd_disk;

 		if (bdev->bd_disk && (disk->flags & GENHD_FL_CD))
 			return 0;
 		return -EINVAL;

 	default:
 		pr_debug(PFX "ioctl %08x not supported\n", command);
 		return -EINVAL;
 	}
 }

 static const struct block_device_operations vdc_fops = {
 	.owner		= THIS_MODULE,
 	.getgeo		= vdc_getgeo,
 	.ioctl		= vdc_ioctl,
 };

 static void vdc_finish(struct vio_driver_state *vio, int err, int waiting_for)
 {
 	if (vio->cmp &&
 	    (waiting_for == -1 ||
 	     vio->cmp->waiting_for == waiting_for)) {
 		vio->cmp->err = err;
 		complete(&vio->cmp->com);
 		vio->cmp = NULL;
 	}
 }

 static void vdc_handshake_complete(struct vio_driver_state *vio)
 {
 	vdc_finish(vio, 0, WAITING_FOR_LINK_UP);
 }

 static int vdc_handle_unknown(struct vdc_port *port, void *arg)
 {
 	struct vio_msg_tag *pkt = arg;

 	printk(KERN_ERR PFX "Received unknown msg [%02x:%02x:%04x:%08x]\n",
 	       pkt->type, pkt->stype, pkt->stype_env, pkt->sid);
 	printk(KERN_ERR PFX "Resetting connection.\n");

 	ldc_disconnect(port->vio.lp);

 	return -ECONNRESET;
 }

 static int vdc_send_attr(struct vio_driver_state *vio)
 {
 	struct vdc_port *port = to_vdc_port(vio);
 	struct vio_disk_attr_info pkt;

 	memset(&pkt, 0, sizeof(pkt));

 	pkt.tag.type = VIO_TYPE_CTRL;
 	pkt.tag.stype = VIO_SUBTYPE_INFO;
 	pkt.tag.stype_env = VIO_ATTR_INFO;
 	pkt.tag.sid = vio_send_sid(vio);

 	pkt.xfer_mode = VIO_DRING_MODE;
 	pkt.vdisk_block_size = port->vdisk_block_size;
 	pkt.max_xfer_size = port->max_xfer_size;

 	viodbg(HS, "SEND ATTR xfer_mode[0x%x] blksz[%u] max_xfer[%llu]\n",
 	       pkt.xfer_mode, pkt.vdisk_block_size, pkt.max_xfer_size);

 	return vio_ldc_send(&port->vio, &pkt, sizeof(pkt));
 }

 static int vdc_handle_attr(struct vio_driver_state *vio, void *arg)
 {
 	struct vdc_port *port = to_vdc_port(vio);
 	struct vio_disk_attr_info *pkt = arg;

 	viodbg(HS, "GOT ATTR stype[0x%x] ops[%llx] disk_size[%llu] disk_type[%x] "
 	       "mtype[0x%x] xfer_mode[0x%x] blksz[%u] max_xfer[%llu]\n",
 	       pkt->tag.stype, pkt->operations,
 	       pkt->vdisk_size, pkt->vdisk_type, pkt->vdisk_mtype,
 	       pkt->xfer_mode, pkt->vdisk_block_size,
 	       pkt->max_xfer_size);

 	if (pkt->tag.stype == VIO_SUBTYPE_ACK) {
 		switch (pkt->vdisk_type) {
 		case VD_DISK_TYPE_DISK:
 		case VD_DISK_TYPE_SLICE:
 			break;

 		default:
 			printk(KERN_ERR PFX "%s: Bogus vdisk_type 0x%x\n",
 			       vio->name, pkt->vdisk_type);
 			return -ECONNRESET;
 		}

 		if (pkt->vdisk_block_size > port->vdisk_block_size) {
 			printk(KERN_ERR PFX "%s: BLOCK size increased "
 			       "%u --> %u\n",
 			       vio->name,
 			       port->vdisk_block_size, pkt->vdisk_block_size);
 			return -ECONNRESET;
 		}

 		port->operations = pkt->operations;
 		port->vdisk_type = pkt->vdisk_type;
 		if (vdc_version_supported(port, 1, 1)) {
 			port->vdisk_size = pkt->vdisk_size;
 			port->vdisk_mtype = pkt->vdisk_mtype;
 		}
 		if (pkt->max_xfer_size < port->max_xfer_size)
 			port->max_xfer_size = pkt->max_xfer_size;
 		port->vdisk_block_size = pkt->vdisk_block_size;
 		return 0;
 	} else {
 		printk(KERN_ERR PFX "%s: Attribute NACK\n", vio->name);

 		return -ECONNRESET;
 	}
 }

 static void vdc_end_special(struct vdc_port *port, struct vio_disk_desc *desc)
 {
 	int err = desc->status;

 	vdc_finish(&port->vio, -err, WAITING_FOR_GEN_CMD);
 }

 static void vdc_end_one(struct vdc_port *port, struct vio_dring_state *dr,
 			unsigned int index)
 {
 	struct vio_disk_desc *desc = vio_dring_entry(dr, index);
 	struct vdc_req_entry *rqe = &port->rq_arr[index];
 	struct request *req;

 	if (unlikely(desc->hdr.state != VIO_DESC_DONE))
 		return;

 	ldc_unmap(port->vio.lp, desc->cookies, desc->ncookies);
 	desc->hdr.state = VIO_DESC_FREE;
 	dr->cons = (index + 1) & (VDC_TX_RING_SIZE - 1);

 	req = rqe->req;
 	if (req == NULL) {
 		vdc_end_special(port, desc);
 		return;
 	}

 	rqe->req = NULL;

 	__blk_end_request(req, (desc->status ? -EIO : 0), desc->size);

 	if (blk_queue_stopped(port->disk->queue))
 		blk_start_queue(port->disk->queue);
 }

 static int vdc_ack(struct vdc_port *port, void *msgbuf)
 {
 	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
 	struct vio_dring_data *pkt = msgbuf;

 	if (unlikely(pkt->dring_ident != dr->ident ||
 		     pkt->start_idx != pkt->end_idx ||
 		     pkt->start_idx >= VDC_TX_RING_SIZE))
 		return 0;

 	vdc_end_one(port, dr, pkt->start_idx);

 	return 0;
 }

 static int vdc_nack(struct vdc_port *port, void *msgbuf)
 {
 	/* XXX Implement me XXX */
 	return 0;
 }

 static void vdc_event(void *arg, int event)
 {
 	struct vdc_port *port = arg;
 	struct vio_driver_state *vio = &port->vio;
 	unsigned long flags;
 	int err;

 	spin_lock_irqsave(&vio->lock, flags);

 	if (unlikely(event == LDC_EVENT_RESET ||
 		     event == LDC_EVENT_UP)) {
 		vio_link_state_change(vio, event);
 		spin_unlock_irqrestore(&vio->lock, flags);
 		return;
 	}

 	if (unlikely(event != LDC_EVENT_DATA_READY)) {
 		printk(KERN_WARNING PFX "Unexpected LDC event %d\n", event);
 		spin_unlock_irqrestore(&vio->lock, flags);
 		return;
 	}

 	err = 0;
 	while (1) {
 		union {
 			struct vio_msg_tag tag;
 			u64 raw[8];
 		} msgbuf;

 		err = ldc_read(vio->lp, &msgbuf, sizeof(msgbuf));
 		if (unlikely(err < 0)) {
 			if (err == -ECONNRESET)
 				vio_conn_reset(vio);
 			break;
 		}
 		if (err == 0)
 			break;
 		viodbg(DATA, "TAG [%02x:%02x:%04x:%08x]\n",
 		       msgbuf.tag.type,
 		       msgbuf.tag.stype,
 		       msgbuf.tag.stype_env,
 		       msgbuf.tag.sid);
 		err = vio_validate_sid(vio, &msgbuf.tag);
 		if (err < 0)
 			break;

 		if (likely(msgbuf.tag.type == VIO_TYPE_DATA)) {
 			if (msgbuf.tag.stype == VIO_SUBTYPE_ACK)
 				err = vdc_ack(port, &msgbuf);
 			else if (msgbuf.tag.stype == VIO_SUBTYPE_NACK)
 				err = vdc_nack(port, &msgbuf);
 			else
 				err = vdc_handle_unknown(port, &msgbuf);
 		} else if (msgbuf.tag.type == VIO_TYPE_CTRL) {
 			err = vio_control_pkt_engine(vio, &msgbuf);
 		} else {
 			err = vdc_handle_unknown(port, &msgbuf);
 		}
 		if (err < 0)
 			break;
 	}
 	if (err < 0)
 		vdc_finish(&port->vio, err, WAITING_FOR_ANY);
 	spin_unlock_irqrestore(&vio->lock, flags);
 }

 static int __vdc_tx_trigger(struct vdc_port *port)
 {
 	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
 	struct vio_dring_data hdr = {
 		.tag = {
 			.type		= VIO_TYPE_DATA,
 			.stype		= VIO_SUBTYPE_INFO,
 			.stype_env	= VIO_DRING_DATA,
 			.sid		= vio_send_sid(&port->vio),
 		},
 		.dring_ident		= dr->ident,
 		.start_idx		= dr->prod,
 		.end_idx		= dr->prod,
 	};
 	int err, delay;

 	hdr.seq = dr->snd_nxt;
 	delay = 1;
 	do {
 		err = vio_ldc_send(&port->vio, &hdr, sizeof(hdr));
 		if (err > 0) {
 			dr->snd_nxt++;
 			break;
 		}
 		udelay(delay);
 		if ((delay <<= 1) > 128)
 			delay = 128;
 	} while (err == -EAGAIN);

 	return err;
 }

 static int __send_request(struct request *req)
 {
 	struct vdc_port *port = req->rq_disk->private_data;
 	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
 	struct scatterlist sg[port->ring_cookies];
 	struct vdc_req_entry *rqe;
 	struct vio_disk_desc *desc;
 	unsigned int map_perm;
 	int nsg, err, i;
 	u64 len;
 	u8 op;

 	map_perm = LDC_MAP_SHADOW | LDC_MAP_DIRECT | LDC_MAP_IO;

 	if (rq_data_dir(req) == READ) {
 		map_perm |= LDC_MAP_W;
 		op = VD_OP_BREAD;
 	} else {
 		map_perm |= LDC_MAP_R;
 		op = VD_OP_BWRITE;
 	}

 	sg_init_table(sg, port->ring_cookies);
 	nsg = blk_rq_map_sg(req->q, req, sg);

 	len = 0;
 	for (i = 0; i < nsg; i++)
 		len += sg[i].length;

 	if (unlikely(vdc_tx_dring_avail(dr) < 1)) {
 		blk_stop_queue(port->disk->queue);
 		err = -ENOMEM;
 		goto out;
 	}

 	desc = vio_dring_cur(dr);

 	err = ldc_map_sg(port->vio.lp, sg, nsg,
 			 desc->cookies, port->ring_cookies,
 			 map_perm);
 	if (err < 0) {
 		printk(KERN_ERR PFX "ldc_map_sg() failure, err=%d.\n", err);
 		return err;
 	}

 	rqe = &port->rq_arr[dr->prod];
 	rqe->req = req;

 	desc->hdr.ack = VIO_ACK_ENABLE;
 	desc->req_id = port->req_id;
 	desc->operation = op;
 	if (port->vdisk_type == VD_DISK_TYPE_DISK) {
 		desc->slice = 0xff;
 	} else {
 		desc->slice = 0;
 	}
 	desc->status = ~0;
 	desc->offset = (blk_rq_pos(req) << 9) / port->vdisk_block_size;
 	desc->size = len;
 	desc->ncookies = err;

 	/* This has to be a non-SMP write barrier because we are writing
 	 * to memory which is shared with the peer LDOM.
 	 */
 	wmb();
 	desc->hdr.state = VIO_DESC_READY;

 	err = __vdc_tx_trigger(port);
 	if (err < 0) {
 		printk(KERN_ERR PFX "vdc_tx_trigger() failure, err=%d\n", err);
 	} else {
 		port->req_id++;
 		dr->prod = (dr->prod + 1) & (VDC_TX_RING_SIZE - 1);
 	}
 out:

 	return err;
 }

 static void do_vdc_request(struct request_queue *q)
 {
 	while (1) {
 		struct request *req = blk_fetch_request(q);

 		if (!req)
 			break;

 		if (__send_request(req) < 0)
 			__blk_end_request_all(req, -EIO);
 	}
 }

 static int generic_request(struct vdc_port *port, u8 op, void *buf, int len)
 {
 	struct vio_dring_state *dr;
 	struct vio_completion comp;
 	struct vio_disk_desc *desc;
 	unsigned int map_perm;
 	unsigned long flags;
 	int op_len, err;
 	void *req_buf;

 	if (!(((u64)1 << (u64)op) & port->operations))
 		return -EOPNOTSUPP;

 	switch (op) {
 	case VD_OP_BREAD:
 	case VD_OP_BWRITE:
 	default:
 		return -EINVAL;

 	case VD_OP_FLUSH:
 		op_len = 0;
 		map_perm = 0;
 		break;

 	case VD_OP_GET_WCE:
 		op_len = sizeof(u32);
 		map_perm = LDC_MAP_W;
 		break;

 	case VD_OP_SET_WCE:
 		op_len = sizeof(u32);
 		map_perm = LDC_MAP_R;
 		break;

 	case VD_OP_GET_VTOC:
 		op_len = sizeof(struct vio_disk_vtoc);
 		map_perm = LDC_MAP_W;
 		break;

 	case VD_OP_SET_VTOC:
 		op_len = sizeof(struct vio_disk_vtoc);
 		map_perm = LDC_MAP_R;
 		break;

 	case VD_OP_GET_DISKGEOM:
 		op_len = sizeof(struct vio_disk_geom);
 		map_perm = LDC_MAP_W;
 		break;

 	case VD_OP_SET_DISKGEOM:
 		op_len = sizeof(struct vio_disk_geom);
 		map_perm = LDC_MAP_R;
 		break;

 	case VD_OP_SCSICMD:
 		op_len = 16;
 		map_perm = LDC_MAP_RW;
 		break;

 	case VD_OP_GET_DEVID:
 		op_len = sizeof(struct vio_disk_devid);
 		map_perm = LDC_MAP_W;
 		break;

 	case VD_OP_GET_EFI:
 	case VD_OP_SET_EFI:
 		return -EOPNOTSUPP;
 		break;
 	};

 	map_perm |= LDC_MAP_SHADOW | LDC_MAP_DIRECT | LDC_MAP_IO;

 	op_len = (op_len + 7) & ~7;
 	req_buf = kzalloc(op_len, GFP_KERNEL);
 	if (!req_buf)
 		return -ENOMEM;

 	if (len > op_len)
 		len = op_len;

 	if (map_perm & LDC_MAP_R)
 		memcpy(req_buf, buf, len);

 	spin_lock_irqsave(&port->vio.lock, flags);

 	dr = &port->vio.drings[VIO_DRIVER_TX_RING];

 	/* XXX If we want to use this code generically we have to
 	 * XXX handle TX ring exhaustion etc.
 	 */
 	desc = vio_dring_cur(dr);

 	err = ldc_map_single(port->vio.lp, req_buf, op_len,
 			     desc->cookies, port->ring_cookies,
 			     map_perm);
 	if (err < 0) {
 		spin_unlock_irqrestore(&port->vio.lock, flags);
 		kfree(req_buf);
 		return err;
 	}

 	init_completion(&comp.com);
 	comp.waiting_for = WAITING_FOR_GEN_CMD;
 	port->vio.cmp = &comp;

 	desc->hdr.ack = VIO_ACK_ENABLE;
 	desc->req_id = port->req_id;
 	desc->operation = op;
 	desc->slice = 0;
 	desc->status = ~0;
 	desc->offset = 0;
 	desc->size = op_len;
 	desc->ncookies = err;

 	/* This has to be a non-SMP write barrier because we are writing
 	 * to memory which is shared with the peer LDOM.
 	 */
 	wmb();
 	desc->hdr.state = VIO_DESC_READY;

 	err = __vdc_tx_trigger(port);
 	if (err >= 0) {
 		port->req_id++;
 		dr->prod = (dr->prod + 1) & (VDC_TX_RING_SIZE - 1);
 		spin_unlock_irqrestore(&port->vio.lock, flags);

 		wait_for_completion(&comp.com);
 		err = comp.err;
 	} else {
 		port->vio.cmp = NULL;
 		spin_unlock_irqrestore(&port->vio.lock, flags);
 	}

 	if (map_perm & LDC_MAP_W)
 		memcpy(buf, req_buf, len);

 	kfree(req_buf);

 	return err;
 }

 static int vdc_alloc_tx_ring(struct vdc_port *port)
 {
 	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
 	unsigned long len, entry_size;
 	int ncookies;
 	void *dring;

 	entry_size = sizeof(struct vio_disk_desc) +
 		(sizeof(struct ldc_trans_cookie) * port->ring_cookies);
 	len = (VDC_TX_RING_SIZE * entry_size);

 	ncookies = VIO_MAX_RING_COOKIES;
 	dring = ldc_alloc_exp_dring(port->vio.lp, len,
 				    dr->cookies, &ncookies,
 				    (LDC_MAP_SHADOW |
 				     LDC_MAP_DIRECT |
 				     LDC_MAP_RW));
 	if (IS_ERR(dring))
 		return PTR_ERR(dring);

 	dr->base = dring;
 	dr->entry_size = entry_size;
 	dr->num_entries = VDC_TX_RING_SIZE;
 	dr->prod = dr->cons = 0;
 	dr->pending = VDC_TX_RING_SIZE;
 	dr->ncookies = ncookies;

 	return 0;
 }

 static void vdc_free_tx_ring(struct vdc_port *port)
 {
 	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];

 	if (dr->base) {
 		ldc_free_exp_dring(port->vio.lp, dr->base,
 				   (dr->entry_size * dr->num_entries),
 				   dr->cookies, dr->ncookies);
 		dr->base = NULL;
 		dr->entry_size = 0;
 		dr->num_entries = 0;
 		dr->pending = 0;
 		dr->ncookies = 0;
 	}
 }

 static int probe_disk(struct vdc_port *port)
 {
 	struct vio_completion comp;
 	struct request_queue *q;
 	struct gendisk *g;
 	int err;

 	init_completion(&comp.com);
 	comp.err = 0;
 	comp.waiting_for = WAITING_FOR_LINK_UP;
 	port->vio.cmp = &comp;

 	vio_port_up(&port->vio);

 	wait_for_completion(&comp.com);
 	if (comp.err)
 		return comp.err;

 	err = generic_request(port, VD_OP_GET_VTOC,
 			      &port->label, sizeof(port->label));
 	if (err < 0) {
 		printk(KERN_ERR PFX "VD_OP_GET_VTOC returns error %d\n", err);
 		return err;
 	}

 	if (vdc_version_supported(port, 1, 1)) {
 		/* vdisk_size should be set during the handshake, if it wasn't
 		 * then the underlying disk is reserved by another system
 		 */
 		if (port->vdisk_size == -1)
 			return -ENODEV;
 	} else {
 		err = generic_request(port, VD_OP_GET_DISKGEOM,
 				      &port->geom, sizeof(port->geom));
 		if (err < 0) {
 			printk(KERN_ERR PFX "VD_OP_GET_DISKGEOM returns "
 			       "error %d\n", err);
 			return err;
 		}
 		port->vdisk_size = ((u64)port->geom.num_cyl *
 				    (u64)port->geom.num_hd *
 				    (u64)port->geom.num_sec);
 	}

 	q = blk_init_queue(do_vdc_request, &port->vio.lock);
 	if (!q) {
 		printk(KERN_ERR PFX "%s: Could not allocate queue.\n",
 		       port->vio.name);
 		return -ENOMEM;
 	}
 	g = alloc_disk(1 << PARTITION_SHIFT);
 	if (!g) {
 		printk(KERN_ERR PFX "%s: Could not allocate gendisk.\n",
 		       port->vio.name);
 		blk_cleanup_queue(q);
 		return -ENOMEM;
 	}

 	port->disk = g;

 	blk_queue_max_segments(q, port->ring_cookies);
 	blk_queue_max_hw_sectors(q, port->max_xfer_size);
 	g->major = vdc_major;
 	g->first_minor = port->vio.vdev->dev_no << PARTITION_SHIFT;
 	strcpy(g->disk_name, port->disk_name);

 	g->fops = &vdc_fops;
 	g->queue = q;
 	g->private_data = port;
 	g->driverfs_dev = &port->vio.vdev->dev;

 	set_capacity(g, port->vdisk_size);

 	if (vdc_version_supported(port, 1, 1)) {
 		switch (port->vdisk_mtype) {
 		case VD_MEDIA_TYPE_CD:
 			pr_info(PFX "Virtual CDROM %s\n", port->disk_name);
 			g->flags |= GENHD_FL_CD;
 			g->flags |= GENHD_FL_REMOVABLE;
 			set_disk_ro(g, 1);
 			break;

 		case VD_MEDIA_TYPE_DVD:
 			pr_info(PFX "Virtual DVD %s\n", port->disk_name);
 			g->flags |= GENHD_FL_CD;
 			g->flags |= GENHD_FL_REMOVABLE;
 			set_disk_ro(g, 1);
 			break;

 		case VD_MEDIA_TYPE_FIXED:
 			pr_info(PFX "Virtual Hard disk %s\n", port->disk_name);
 			break;
 		}
 	}

 	pr_info(PFX "%s: %u sectors (%u MB) protocol %d.%d\n",
 	       g->disk_name,
 	       port->vdisk_size, (port->vdisk_size >> (20 - 9)),
 	       port->vio.ver.major, port->vio.ver.minor);

 	add_disk(g);

 	return 0;
 }

 static struct ldc_channel_config vdc_ldc_cfg = {
 	.event		= vdc_event,
 	.mtu		= 64,
 	.mode		= LDC_MODE_UNRELIABLE,
 };

 static struct vio_driver_ops vdc_vio_ops = {
 	.send_attr		= vdc_send_attr,
 	.handle_attr		= vdc_handle_attr,
 	.handshake_complete	= vdc_handshake_complete,
 };

 static void print_version(void)
 {
 	static int version_printed;

 	if (version_printed++ == 0)
 		printk(KERN_INFO "%s", version);
 }

 static int vdc_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 {
 	struct mdesc_handle *hp;
 	struct vdc_port *port;
 	int err;

 	print_version();

 	hp = mdesc_grab();

 	err = -ENODEV;
 	if ((vdev->dev_no << PARTITION_SHIFT) & ~(u64)MINORMASK) {
 		printk(KERN_ERR PFX "Port id [%llu] too large.\n",
 		       vdev->dev_no);
 		goto err_out_release_mdesc;
 	}

 	port = kzalloc(sizeof(*port), GFP_KERNEL);
 	err = -ENOMEM;
 	if (!port) {
 		printk(KERN_ERR PFX "Cannot allocate vdc_port.\n");
 		goto err_out_release_mdesc;
 	}

 	if (vdev->dev_no >= 26)
 		snprintf(port->disk_name, sizeof(port->disk_name),
 			 VDCBLK_NAME "%c%c",
 			 'a' + ((int)vdev->dev_no / 26) - 1,
 			 'a' + ((int)vdev->dev_no % 26));
 	else
 		snprintf(port->disk_name, sizeof(port->disk_name),
 			 VDCBLK_NAME "%c", 'a' + ((int)vdev->dev_no % 26));
 	port->vdisk_size = -1;

 	err = vio_driver_init(&port->vio, vdev, VDEV_DISK,
 			      vdc_versions, ARRAY_SIZE(vdc_versions),
 			      &vdc_vio_ops, port->disk_name);
 	if (err)
 		goto err_out_free_port;

 	port->vdisk_block_size = 512;
 	port->max_xfer_size = ((128 * 1024) / port->vdisk_block_size);
 	port->ring_cookies = ((port->max_xfer_size *
 			       port->vdisk_block_size) / PAGE_SIZE) + 2;

 	err = vio_ldc_alloc(&port->vio, &vdc_ldc_cfg, port);
 	if (err)
 		goto err_out_free_port;

 	err = vdc_alloc_tx_ring(port);
 	if (err)
 		goto err_out_free_ldc;

 	err = probe_disk(port);
 	if (err)
 		goto err_out_free_tx_ring;

 	dev_set_drvdata(&vdev->dev, port);

 	mdesc_release(hp);

 	return 0;

 err_out_free_tx_ring:
 	vdc_free_tx_ring(port);

 err_out_free_ldc:
 	vio_ldc_free(&port->vio);

 err_out_free_port:
 	kfree(port);

 err_out_release_mdesc:
 	mdesc_release(hp);
 	return err;
 }

 static int vdc_port_remove(struct vio_dev *vdev)
 {
 	struct vdc_port *port = dev_get_drvdata(&vdev->dev);

 	if (port) {
 		del_timer_sync(&port->vio.timer);

 		vdc_free_tx_ring(port);
 		vio_ldc_free(&port->vio);

 		dev_set_drvdata(&vdev->dev, NULL);

 		kfree(port);
 	}
 	return 0;
 }

 static const struct vio_device_id vdc_port_match[] = {
 	{
 		.type = "vdc-port",
 	},
 	{},
 };
 MODULE_DEVICE_TABLE(vio, vdc_port_match);

 static struct vio_driver vdc_port_driver = {
 	.id_table	= vdc_port_match,
 	.probe		= vdc_port_probe,
 	.remove		= vdc_port_remove,
 	.name		= "vdc_port",
 };

 static int __init vdc_init(void)
 {
 	int err;

 	err = register_blkdev(0, VDCBLK_NAME);
 	if (err < 0)
 		goto out_err;

 	vdc_major = err;

 	err = vio_register_driver(&vdc_port_driver);
 	if (err)
 		goto out_unregister_blkdev;

 	return 0;

 out_unregister_blkdev:
 	unregister_blkdev(vdc_major, VDCBLK_NAME);
 	vdc_major = 0;

 out_err:
 	return err;
 }

 static void __exit vdc_exit(void)
 {
 	vio_unregister_driver(&vdc_port_driver);
 	unregister_blkdev(vdc_major, VDCBLK_NAME);
 }

 module_init(vdc_init);
 module_exit(vdc_exit);
	/* sunvdc.c: Sun LDOM Virtual Disk Client.
	*
	* Copyright (C) 2007, 2008 David S. Miller <davem@davemloft.net>
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/types.h>
	#include <linux/blkdev.h>
	#include <linux/hdreg.h>
	#include <linux/genhd.h>
	#include <linux/cdrom.h>
	#include <linux/slab.h>
	#include <linux/spinlock.h>
	#include <linux/completion.h>
	#include <linux/delay.h>
	#include <linux/init.h>
	#include <linux/list.h>
	#include <linux/scatterlist.h>

	#include <asm/vio.h>
	#include <asm/ldc.h>

	#define DRV_MODULE_NAME "sunvdc"
	#define PFX DRV_MODULE_NAME ": "
	#define DRV_MODULE_VERSION "1.1"
	#define DRV_MODULE_RELDATE "February 13, 2013"

	static char version[] =
	DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";
	MODULE_AUTHOR("David S. Miller (davem@davemloft.net)");
	MODULE_DESCRIPTION("Sun LDOM virtual disk client driver");
	MODULE_LICENSE("GPL");
	MODULE_VERSION(DRV_MODULE_VERSION);

	#define VDC_TX_RING_SIZE 256

	#define WAITING_FOR_LINK_UP 0x01
	#define WAITING_FOR_TX_SPACE 0x02
	#define WAITING_FOR_GEN_CMD 0x04
	#define WAITING_FOR_ANY -1

	struct vdc_req_entry {
	struct request *req;
	};

	struct vdc_port {
	struct vio_driver_state vio;

	struct gendisk *disk;

	struct vdc_completion *cmp;

	u64 req_id;
	u64 seq;
	struct vdc_req_entry rq_arr[VDC_TX_RING_SIZE];

	unsigned long ring_cookies;

	u64 max_xfer_size;
	u32 vdisk_block_size;

	/* The server fills these in for us in the disk attribute
	* ACK packet.
	*/
	u64 operations;
	u32 vdisk_size;
	u8 vdisk_type;
	u8 vdisk_mtype;

	char disk_name[32];

	struct vio_disk_geom geom;
	struct vio_disk_vtoc label;
	};

	static inline struct vdc_port to_vdc_port(struct vio_driver_state vio)
	{
	return container_of(vio, struct vdc_port, vio);
	}

	/* Ordered from largest major to lowest */
	static struct vio_version vdc_versions[] = {
	{ .major = 1, .minor = 1 },
	{ .major = 1, .minor = 0 },
	};

	static inline int vdc_version_supported(struct vdc_port *port,
	u16 major, u16 minor)
	{
	return port->vio.ver.major == major && port->vio.ver.minor >= minor;
	}

	#define VDCBLK_NAME "vdisk"
	static int vdc_major;
	#define PARTITION_SHIFT 3

	static inline u32 vdc_tx_dring_avail(struct vio_dring_state *dr)
	{
	return vio_dring_avail(dr, VDC_TX_RING_SIZE);
	}

	static int vdc_getgeo(struct block_device bdev, struct hd_geometry geo)
	{
	struct gendisk *disk = bdev->bd_disk;
	struct vdc_port *port = disk->private_data;

	geo->heads = (u8) port->geom.num_hd;
	geo->sectors = (u8) port->geom.num_sec;
	geo->cylinders = port->geom.num_cyl;

	return 0;
	}

	/* Add ioctl/CDROM_GET_CAPABILITY to support cdrom_id in udev
	* when vdisk_mtype is VD_MEDIA_TYPE_CD or VD_MEDIA_TYPE_DVD.
	* Needed to be able to install inside an ldom from an iso image.
	*/
	static int vdc_ioctl(struct block_device *bdev, fmode_t mode,
	unsigned command, unsigned long argument)
	{
	int i;
	struct gendisk *disk;

	switch (command) {
	case CDROMMULTISESSION:
	pr_debug(PFX "Multisession CDs not supported\n");
	for (i = 0; i < sizeof(struct cdrom_multisession); i++)
	if (put_user(0, (char __user *)(argument + i)))
	return -EFAULT;
	return 0;

	case CDROM_GET_CAPABILITY:
	disk = bdev->bd_disk;

	if (bdev->bd_disk && (disk->flags & GENHD_FL_CD))
	return 0;
	return -EINVAL;

	default:
	pr_debug(PFX "ioctl %08x not supported\n", command);
	return -EINVAL;
	}
	}

	static const struct block_device_operations vdc_fops = {
	.owner = THIS_MODULE,
	.getgeo = vdc_getgeo,
	.ioctl = vdc_ioctl,
	};

	static void vdc_finish(struct vio_driver_state *vio, int err, int waiting_for)
	{
	if (vio->cmp &&
	(waiting_for == -1 \|\|
	vio->cmp->waiting_for == waiting_for)) {
	vio->cmp->err = err;
	complete(&vio->cmp->com);
	vio->cmp = NULL;
	}
	}

	static void vdc_handshake_complete(struct vio_driver_state *vio)
	{
	vdc_finish(vio, 0, WAITING_FOR_LINK_UP);
	}

	static int vdc_handle_unknown(struct vdc_port port, void arg)
	{
	struct vio_msg_tag *pkt = arg;

	printk(KERN_ERR PFX "Received unknown msg [%02x:%02x:%04x:%08x]\n",
	pkt->type, pkt->stype, pkt->stype_env, pkt->sid);
	printk(KERN_ERR PFX "Resetting connection.\n");

	ldc_disconnect(port->vio.lp);

	return -ECONNRESET;
	}

	static int vdc_send_attr(struct vio_driver_state *vio)
	{
	struct vdc_port *port = to_vdc_port(vio);
	struct vio_disk_attr_info pkt;

	memset(&pkt, 0, sizeof(pkt));

	pkt.tag.type = VIO_TYPE_CTRL;
	pkt.tag.stype = VIO_SUBTYPE_INFO;
	pkt.tag.stype_env = VIO_ATTR_INFO;
	pkt.tag.sid = vio_send_sid(vio);

	pkt.xfer_mode = VIO_DRING_MODE;
	pkt.vdisk_block_size = port->vdisk_block_size;
	pkt.max_xfer_size = port->max_xfer_size;

	viodbg(HS, "SEND ATTR xfer_mode[0x%x] blksz[%u] max_xfer[%llu]\n",
	pkt.xfer_mode, pkt.vdisk_block_size, pkt.max_xfer_size);

	return vio_ldc_send(&port->vio, &pkt, sizeof(pkt));
	}

	static int vdc_handle_attr(struct vio_driver_state vio, void arg)
	{
	struct vdc_port *port = to_vdc_port(vio);
	struct vio_disk_attr_info *pkt = arg;

	viodbg(HS, "GOT ATTR stype[0x%x] ops[%llx] disk_size[%llu] disk_type[%x] "
	"mtype[0x%x] xfer_mode[0x%x] blksz[%u] max_xfer[%llu]\n",
	pkt->tag.stype, pkt->operations,
	pkt->vdisk_size, pkt->vdisk_type, pkt->vdisk_mtype,
	pkt->xfer_mode, pkt->vdisk_block_size,
	pkt->max_xfer_size);

	if (pkt->tag.stype == VIO_SUBTYPE_ACK) {
	switch (pkt->vdisk_type) {
	case VD_DISK_TYPE_DISK:
	case VD_DISK_TYPE_SLICE:
	break;

	default:
	printk(KERN_ERR PFX "%s: Bogus vdisk_type 0x%x\n",
	vio->name, pkt->vdisk_type);
	return -ECONNRESET;
	}

	if (pkt->vdisk_block_size > port->vdisk_block_size) {
	printk(KERN_ERR PFX "%s: BLOCK size increased "
	"%u --> %u\n",
	vio->name,
	port->vdisk_block_size, pkt->vdisk_block_size);
	return -ECONNRESET;
	}

	port->operations = pkt->operations;
	port->vdisk_type = pkt->vdisk_type;
	if (vdc_version_supported(port, 1, 1)) {
	port->vdisk_size = pkt->vdisk_size;
	port->vdisk_mtype = pkt->vdisk_mtype;
	}
	if (pkt->max_xfer_size < port->max_xfer_size)
	port->max_xfer_size = pkt->max_xfer_size;
	port->vdisk_block_size = pkt->vdisk_block_size;
	return 0;
	} else {
	printk(KERN_ERR PFX "%s: Attribute NACK\n", vio->name);

	return -ECONNRESET;
	}
	}

	static void vdc_end_special(struct vdc_port port, struct vio_disk_desc desc)
	{
	int err = desc->status;

	vdc_finish(&port->vio, -err, WAITING_FOR_GEN_CMD);
	}

	static void vdc_end_one(struct vdc_port port, struct vio_dring_state dr,
	unsigned int index)
	{
	struct vio_disk_desc *desc = vio_dring_entry(dr, index);
	struct vdc_req_entry *rqe = &port->rq_arr[index];
	struct request *req;

	if (unlikely(desc->hdr.state != VIO_DESC_DONE))
	return;

	ldc_unmap(port->vio.lp, desc->cookies, desc->ncookies);
	desc->hdr.state = VIO_DESC_FREE;
	dr->cons = (index + 1) & (VDC_TX_RING_SIZE - 1);

	req = rqe->req;
	if (req == NULL) {
	vdc_end_special(port, desc);
	return;
	}

	rqe->req = NULL;

	__blk_end_request(req, (desc->status ? -EIO : 0), desc->size);

	if (blk_queue_stopped(port->disk->queue))
	blk_start_queue(port->disk->queue);
	}

	static int vdc_ack(struct vdc_port port, void msgbuf)
	{
	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
	struct vio_dring_data *pkt = msgbuf;

	if (unlikely(pkt->dring_ident != dr->ident \|\|
	pkt->start_idx != pkt->end_idx \|\|
	pkt->start_idx >= VDC_TX_RING_SIZE))
	return 0;

	vdc_end_one(port, dr, pkt->start_idx);

	return 0;
	}

	static int vdc_nack(struct vdc_port port, void msgbuf)
	{
	/* XXX Implement me XXX */
	return 0;
	}

	static void vdc_event(void *arg, int event)
	{
	struct vdc_port *port = arg;
	struct vio_driver_state *vio = &port->vio;
	unsigned long flags;
	int err;

	spin_lock_irqsave(&vio->lock, flags);

	if (unlikely(event == LDC_EVENT_RESET \|\|
	event == LDC_EVENT_UP)) {
	vio_link_state_change(vio, event);
	spin_unlock_irqrestore(&vio->lock, flags);
	return;
	}

	if (unlikely(event != LDC_EVENT_DATA_READY)) {
	printk(KERN_WARNING PFX "Unexpected LDC event %d\n", event);
	spin_unlock_irqrestore(&vio->lock, flags);
	return;
	}

	err = 0;
	while (1) {
	union {
	struct vio_msg_tag tag;
	u64 raw[8];
	} msgbuf;

	err = ldc_read(vio->lp, &msgbuf, sizeof(msgbuf));
	if (unlikely(err < 0)) {
	if (err == -ECONNRESET)
	vio_conn_reset(vio);
	break;
	}
	if (err == 0)
	break;
	viodbg(DATA, "TAG [%02x:%02x:%04x:%08x]\n",
	msgbuf.tag.type,
	msgbuf.tag.stype,
	msgbuf.tag.stype_env,
	msgbuf.tag.sid);
	err = vio_validate_sid(vio, &msgbuf.tag);
	if (err < 0)
	break;

	if (likely(msgbuf.tag.type == VIO_TYPE_DATA)) {
	if (msgbuf.tag.stype == VIO_SUBTYPE_ACK)
	err = vdc_ack(port, &msgbuf);
	else if (msgbuf.tag.stype == VIO_SUBTYPE_NACK)
	err = vdc_nack(port, &msgbuf);
	else
	err = vdc_handle_unknown(port, &msgbuf);
	} else if (msgbuf.tag.type == VIO_TYPE_CTRL) {
	err = vio_control_pkt_engine(vio, &msgbuf);
	} else {
	err = vdc_handle_unknown(port, &msgbuf);
	}
	if (err < 0)
	break;
	}
	if (err < 0)
	vdc_finish(&port->vio, err, WAITING_FOR_ANY);
	spin_unlock_irqrestore(&vio->lock, flags);
	}

	static int __vdc_tx_trigger(struct vdc_port *port)
	{
	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
	struct vio_dring_data hdr = {
	.tag = {
	.type = VIO_TYPE_DATA,
	.stype = VIO_SUBTYPE_INFO,
	.stype_env = VIO_DRING_DATA,
	.sid = vio_send_sid(&port->vio),
	},
	.dring_ident = dr->ident,
	.start_idx = dr->prod,
	.end_idx = dr->prod,
	};
	int err, delay;

	hdr.seq = dr->snd_nxt;
	delay = 1;
	do {
	err = vio_ldc_send(&port->vio, &hdr, sizeof(hdr));
	if (err > 0) {
	dr->snd_nxt++;
	break;
	}
	udelay(delay);
	if ((delay <<= 1) > 128)
	delay = 128;
	} while (err == -EAGAIN);

	return err;
	}

	static int __send_request(struct request *req)
	{
	struct vdc_port *port = req->rq_disk->private_data;
	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
	struct scatterlist sg[port->ring_cookies];
	struct vdc_req_entry *rqe;
	struct vio_disk_desc *desc;
	unsigned int map_perm;
	int nsg, err, i;
	u64 len;
	u8 op;

	map_perm = LDC_MAP_SHADOW \| LDC_MAP_DIRECT \| LDC_MAP_IO;

	if (rq_data_dir(req) == READ) {
	map_perm \|= LDC_MAP_W;
	op = VD_OP_BREAD;
	} else {
	map_perm \|= LDC_MAP_R;
	op = VD_OP_BWRITE;
	}

	sg_init_table(sg, port->ring_cookies);
	nsg = blk_rq_map_sg(req->q, req, sg);

	len = 0;
	for (i = 0; i < nsg; i++)
	len += sg[i].length;

	if (unlikely(vdc_tx_dring_avail(dr) < 1)) {
	blk_stop_queue(port->disk->queue);
	err = -ENOMEM;
	goto out;
	}

	desc = vio_dring_cur(dr);

	err = ldc_map_sg(port->vio.lp, sg, nsg,
	desc->cookies, port->ring_cookies,
	map_perm);
	if (err < 0) {
	printk(KERN_ERR PFX "ldc_map_sg() failure, err=%d.\n", err);
	return err;
	}

	rqe = &port->rq_arr[dr->prod];
	rqe->req = req;

	desc->hdr.ack = VIO_ACK_ENABLE;
	desc->req_id = port->req_id;
	desc->operation = op;
	if (port->vdisk_type == VD_DISK_TYPE_DISK) {
	desc->slice = 0xff;
	} else {
	desc->slice = 0;
	}
	desc->status = ~0;
	desc->offset = (blk_rq_pos(req) << 9) / port->vdisk_block_size;
	desc->size = len;
	desc->ncookies = err;

	/* This has to be a non-SMP write barrier because we are writing
	* to memory which is shared with the peer LDOM.
	*/
	wmb();
	desc->hdr.state = VIO_DESC_READY;

	err = __vdc_tx_trigger(port);
	if (err < 0) {
	printk(KERN_ERR PFX "vdc_tx_trigger() failure, err=%d\n", err);
	} else {
	port->req_id++;
	dr->prod = (dr->prod + 1) & (VDC_TX_RING_SIZE - 1);
	}
	out:

	return err;
	}

	static void do_vdc_request(struct request_queue *q)
	{
	while (1) {
	struct request *req = blk_fetch_request(q);

	if (!req)
	break;

	if (__send_request(req) < 0)
	__blk_end_request_all(req, -EIO);
	}
	}

	static int generic_request(struct vdc_port port, u8 op, void buf, int len)
	{
	struct vio_dring_state *dr;
	struct vio_completion comp;
	struct vio_disk_desc *desc;
	unsigned int map_perm;
	unsigned long flags;
	int op_len, err;
	void *req_buf;

	if (!(((u64)1 << (u64)op) & port->operations))
	return -EOPNOTSUPP;

	switch (op) {
	case VD_OP_BREAD:
	case VD_OP_BWRITE:
	default:
	return -EINVAL;

	case VD_OP_FLUSH:
	op_len = 0;
	map_perm = 0;
	break;

	case VD_OP_GET_WCE:
	op_len = sizeof(u32);
	map_perm = LDC_MAP_W;
	break;

	case VD_OP_SET_WCE:
	op_len = sizeof(u32);
	map_perm = LDC_MAP_R;
	break;

	case VD_OP_GET_VTOC:
	op_len = sizeof(struct vio_disk_vtoc);
	map_perm = LDC_MAP_W;
	break;

	case VD_OP_SET_VTOC:
	op_len = sizeof(struct vio_disk_vtoc);
	map_perm = LDC_MAP_R;
	break;

	case VD_OP_GET_DISKGEOM:
	op_len = sizeof(struct vio_disk_geom);
	map_perm = LDC_MAP_W;
	break;

	case VD_OP_SET_DISKGEOM:
	op_len = sizeof(struct vio_disk_geom);
	map_perm = LDC_MAP_R;
	break;

	case VD_OP_SCSICMD:
	op_len = 16;
	map_perm = LDC_MAP_RW;
	break;

	case VD_OP_GET_DEVID:
	op_len = sizeof(struct vio_disk_devid);
	map_perm = LDC_MAP_W;
	break;

	case VD_OP_GET_EFI:
	case VD_OP_SET_EFI:
	return -EOPNOTSUPP;
	break;
	};

	map_perm \|= LDC_MAP_SHADOW \| LDC_MAP_DIRECT \| LDC_MAP_IO;

	op_len = (op_len + 7) & ~7;
	req_buf = kzalloc(op_len, GFP_KERNEL);
	if (!req_buf)
	return -ENOMEM;

	if (len > op_len)
	len = op_len;

	if (map_perm & LDC_MAP_R)
	memcpy(req_buf, buf, len);

	spin_lock_irqsave(&port->vio.lock, flags);

	dr = &port->vio.drings[VIO_DRIVER_TX_RING];

	/* XXX If we want to use this code generically we have to
	* XXX handle TX ring exhaustion etc.
	*/
	desc = vio_dring_cur(dr);

	err = ldc_map_single(port->vio.lp, req_buf, op_len,
	desc->cookies, port->ring_cookies,
	map_perm);
	if (err < 0) {
	spin_unlock_irqrestore(&port->vio.lock, flags);
	kfree(req_buf);
	return err;
	}

	init_completion(&comp.com);
	comp.waiting_for = WAITING_FOR_GEN_CMD;
	port->vio.cmp = &comp;

	desc->hdr.ack = VIO_ACK_ENABLE;
	desc->req_id = port->req_id;
	desc->operation = op;
	desc->slice = 0;
	desc->status = ~0;
	desc->offset = 0;
	desc->size = op_len;
	desc->ncookies = err;

	/* This has to be a non-SMP write barrier because we are writing
	* to memory which is shared with the peer LDOM.
	*/
	wmb();
	desc->hdr.state = VIO_DESC_READY;

	err = __vdc_tx_trigger(port);
	if (err >= 0) {
	port->req_id++;
	dr->prod = (dr->prod + 1) & (VDC_TX_RING_SIZE - 1);
	spin_unlock_irqrestore(&port->vio.lock, flags);

	wait_for_completion(&comp.com);
	err = comp.err;
	} else {
	port->vio.cmp = NULL;
	spin_unlock_irqrestore(&port->vio.lock, flags);
	}

	if (map_perm & LDC_MAP_W)
	memcpy(buf, req_buf, len);

	kfree(req_buf);

	return err;
	}

	static int vdc_alloc_tx_ring(struct vdc_port *port)
	{
	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];
	unsigned long len, entry_size;
	int ncookies;
	void *dring;

	entry_size = sizeof(struct vio_disk_desc) +
	(sizeof(struct ldc_trans_cookie) * port->ring_cookies);
	len = (VDC_TX_RING_SIZE * entry_size);

	ncookies = VIO_MAX_RING_COOKIES;
	dring = ldc_alloc_exp_dring(port->vio.lp, len,
	dr->cookies, &ncookies,
	(LDC_MAP_SHADOW \|
	LDC_MAP_DIRECT \|
	LDC_MAP_RW));
	if (IS_ERR(dring))
	return PTR_ERR(dring);

	dr->base = dring;
	dr->entry_size = entry_size;
	dr->num_entries = VDC_TX_RING_SIZE;
	dr->prod = dr->cons = 0;
	dr->pending = VDC_TX_RING_SIZE;
	dr->ncookies = ncookies;

	return 0;
	}

	static void vdc_free_tx_ring(struct vdc_port *port)
	{
	struct vio_dring_state *dr = &port->vio.drings[VIO_DRIVER_TX_RING];

	if (dr->base) {
	ldc_free_exp_dring(port->vio.lp, dr->base,
	(dr->entry_size * dr->num_entries),
	dr->cookies, dr->ncookies);
	dr->base = NULL;
	dr->entry_size = 0;
	dr->num_entries = 0;
	dr->pending = 0;
	dr->ncookies = 0;
	}
	}

	static int probe_disk(struct vdc_port *port)
	{
	struct vio_completion comp;
	struct request_queue *q;
	struct gendisk *g;
	int err;

	init_completion(&comp.com);
	comp.err = 0;
	comp.waiting_for = WAITING_FOR_LINK_UP;
	port->vio.cmp = &comp;

	vio_port_up(&port->vio);

	wait_for_completion(&comp.com);
	if (comp.err)
	return comp.err;

	err = generic_request(port, VD_OP_GET_VTOC,
	&port->label, sizeof(port->label));
	if (err < 0) {
	printk(KERN_ERR PFX "VD_OP_GET_VTOC returns error %d\n", err);
	return err;
	}

	if (vdc_version_supported(port, 1, 1)) {
	/* vdisk_size should be set during the handshake, if it wasn't
	* then the underlying disk is reserved by another system
	*/
	if (port->vdisk_size == -1)
	return -ENODEV;
	} else {
	err = generic_request(port, VD_OP_GET_DISKGEOM,
	&port->geom, sizeof(port->geom));
	if (err < 0) {
	printk(KERN_ERR PFX "VD_OP_GET_DISKGEOM returns "
	"error %d\n", err);
	return err;
	}
	port->vdisk_size = ((u64)port->geom.num_cyl *
	(u64)port->geom.num_hd *
	(u64)port->geom.num_sec);
	}

	q = blk_init_queue(do_vdc_request, &port->vio.lock);
	if (!q) {
	printk(KERN_ERR PFX "%s: Could not allocate queue.\n",
	port->vio.name);
	return -ENOMEM;
	}
	g = alloc_disk(1 << PARTITION_SHIFT);
	if (!g) {
	printk(KERN_ERR PFX "%s: Could not allocate gendisk.\n",
	port->vio.name);
	blk_cleanup_queue(q);
	return -ENOMEM;
	}

	port->disk = g;

	blk_queue_max_segments(q, port->ring_cookies);
	blk_queue_max_hw_sectors(q, port->max_xfer_size);
	g->major = vdc_major;
	g->first_minor = port->vio.vdev->dev_no << PARTITION_SHIFT;
	strcpy(g->disk_name, port->disk_name);

	g->fops = &vdc_fops;
	g->queue = q;
	g->private_data = port;
	g->driverfs_dev = &port->vio.vdev->dev;

	set_capacity(g, port->vdisk_size);

	if (vdc_version_supported(port, 1, 1)) {
	switch (port->vdisk_mtype) {
	case VD_MEDIA_TYPE_CD:
	pr_info(PFX "Virtual CDROM %s\n", port->disk_name);
	g->flags \|= GENHD_FL_CD;
	g->flags \|= GENHD_FL_REMOVABLE;
	set_disk_ro(g, 1);
	break;

	case VD_MEDIA_TYPE_DVD:
	pr_info(PFX "Virtual DVD %s\n", port->disk_name);
	g->flags \|= GENHD_FL_CD;
	g->flags \|= GENHD_FL_REMOVABLE;
	set_disk_ro(g, 1);
	break;

	case VD_MEDIA_TYPE_FIXED:
	pr_info(PFX "Virtual Hard disk %s\n", port->disk_name);
	break;
	}
	}

	pr_info(PFX "%s: %u sectors (%u MB) protocol %d.%d\n",
	g->disk_name,
	port->vdisk_size, (port->vdisk_size >> (20 - 9)),
	port->vio.ver.major, port->vio.ver.minor);

	add_disk(g);

	return 0;
	}

	static struct ldc_channel_config vdc_ldc_cfg = {
	.event = vdc_event,
	.mtu = 64,
	.mode = LDC_MODE_UNRELIABLE,
	};

	static struct vio_driver_ops vdc_vio_ops = {
	.send_attr = vdc_send_attr,
	.handle_attr = vdc_handle_attr,
	.handshake_complete = vdc_handshake_complete,
	};

	static void print_version(void)
	{
	static int version_printed;

	if (version_printed++ == 0)
	printk(KERN_INFO "%s", version);
	}

	static int vdc_port_probe(struct vio_dev vdev, const struct vio_device_id id)
	{
	struct mdesc_handle *hp;
	struct vdc_port *port;
	int err;

	print_version();

	hp = mdesc_grab();

	err = -ENODEV;
	if ((vdev->dev_no << PARTITION_SHIFT) & ~(u64)MINORMASK) {
	printk(KERN_ERR PFX "Port id [%llu] too large.\n",
	vdev->dev_no);
	goto err_out_release_mdesc;
	}

	port = kzalloc(sizeof(*port), GFP_KERNEL);
	err = -ENOMEM;
	if (!port) {
	printk(KERN_ERR PFX "Cannot allocate vdc_port.\n");
	goto err_out_release_mdesc;
	}

	if (vdev->dev_no >= 26)
	snprintf(port->disk_name, sizeof(port->disk_name),
	VDCBLK_NAME "%c%c",
	'a' + ((int)vdev->dev_no / 26) - 1,
	'a' + ((int)vdev->dev_no % 26));
	else
	snprintf(port->disk_name, sizeof(port->disk_name),
	VDCBLK_NAME "%c", 'a' + ((int)vdev->dev_no % 26));
	port->vdisk_size = -1;

	err = vio_driver_init(&port->vio, vdev, VDEV_DISK,
	vdc_versions, ARRAY_SIZE(vdc_versions),
	&vdc_vio_ops, port->disk_name);
	if (err)
	goto err_out_free_port;

	port->vdisk_block_size = 512;
	port->max_xfer_size = ((128 * 1024) / port->vdisk_block_size);
	port->ring_cookies = ((port->max_xfer_size *
	port->vdisk_block_size) / PAGE_SIZE) + 2;

	err = vio_ldc_alloc(&port->vio, &vdc_ldc_cfg, port);
	if (err)
	goto err_out_free_port;

	err = vdc_alloc_tx_ring(port);
	if (err)
	goto err_out_free_ldc;

	err = probe_disk(port);
	if (err)
	goto err_out_free_tx_ring;

	dev_set_drvdata(&vdev->dev, port);

	mdesc_release(hp);

	return 0;

	err_out_free_tx_ring:
	vdc_free_tx_ring(port);

	err_out_free_ldc:
	vio_ldc_free(&port->vio);

	err_out_free_port:
	kfree(port);

	err_out_release_mdesc:
	mdesc_release(hp);
	return err;
	}

	static int vdc_port_remove(struct vio_dev *vdev)
	{
	struct vdc_port *port = dev_get_drvdata(&vdev->dev);

	if (port) {
	del_timer_sync(&port->vio.timer);

	vdc_free_tx_ring(port);
	vio_ldc_free(&port->vio);

	dev_set_drvdata(&vdev->dev, NULL);

	kfree(port);
	}
	return 0;
	}

	static const struct vio_device_id vdc_port_match[] = {
	{
	.type = "vdc-port",
	},
	{},
	};
	MODULE_DEVICE_TABLE(vio, vdc_port_match);

	static struct vio_driver vdc_port_driver = {
	.id_table = vdc_port_match,
	.probe = vdc_port_probe,
	.remove = vdc_port_remove,
	.name = "vdc_port",
	};

	static int __init vdc_init(void)
	{
	int err;

	err = register_blkdev(0, VDCBLK_NAME);
	if (err < 0)
	goto out_err;

	vdc_major = err;

	err = vio_register_driver(&vdc_port_driver);
	if (err)
	goto out_unregister_blkdev;

	return 0;

	out_unregister_blkdev:
	unregister_blkdev(vdc_major, VDCBLK_NAME);
	vdc_major = 0;

	out_err:
	return err;
	}

	static void __exit vdc_exit(void)
	{
	vio_unregister_driver(&vdc_port_driver);
	unregister_blkdev(vdc_major, VDCBLK_NAME);
	}

	module_init(vdc_init);
	module_exit(vdc_exit);