These changes are the raw update to linux-4.4.6-rt14. Kernel sources

are taken from kernel.org, and rt patch from the rt wiki download page.

During the rebasing, the following patch collided:

Force tick interrupt and get rid of softirq magic(I70131fb85).

Collisions have been removed because its logic was found on the
source already.

Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769
Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>

1 files changed, 1416 insertions, 0 deletions

diff --git a/kernel/drivers/s390/virtio/virtio_ccw.c b/kernel/drivers/s390/virtio/virtio_ccw.c
new file mode 100644
index 000000000..1b831598d
--- /dev/null
+++ b/kernel/drivers/s390/virtio/virtio_ccw.c
@@ -0,0 +1,1416 @@
+/*
+ * ccw based virtio transport
+ *
+ * Copyright IBM Corp. 2012, 2014
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ *    Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/err.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/virtio_ring.h>
+#include <linux/pfn.h>
+#include <linux/async.h>
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/kvm_para.h>
+#include <linux/notifier.h>
+#include <asm/diag.h>
+#include <asm/setup.h>
+#include <asm/irq.h>
+#include <asm/cio.h>
+#include <asm/ccwdev.h>
+#include <asm/virtio-ccw.h>
+#include <asm/isc.h>
+#include <asm/airq.h>
+
+/*
+ * virtio related functions
+ */
+
+struct vq_config_block {
+	__u16 index;
+	__u16 num;
+} __packed;
+
+#define VIRTIO_CCW_CONFIG_SIZE 0x100
+/* same as PCI config space size, should be enough for all drivers */
+
+struct virtio_ccw_device {
+	struct virtio_device vdev;
+	__u8 *status;
+	__u8 config[VIRTIO_CCW_CONFIG_SIZE];
+	struct ccw_device *cdev;
+	__u32 curr_io;
+	int err;
+	unsigned int revision; /* Transport revision */
+	wait_queue_head_t wait_q;
+	spinlock_t lock;
+	struct list_head virtqueues;
+	unsigned long indicators;
+	unsigned long indicators2;
+	struct vq_config_block *config_block;
+	bool is_thinint;
+	bool going_away;
+	bool device_lost;
+	unsigned int config_ready;
+	void *airq_info;
+};
+
+struct vq_info_block_legacy {
+	__u64 queue;
+	__u32 align;
+	__u16 index;
+	__u16 num;
+} __packed;
+
+struct vq_info_block {
+	__u64 desc;
+	__u32 res0;
+	__u16 index;
+	__u16 num;
+	__u64 avail;
+	__u64 used;
+} __packed;
+
+struct virtio_feature_desc {
+	__u32 features;
+	__u8 index;
+} __packed;
+
+struct virtio_thinint_area {
+	unsigned long summary_indicator;
+	unsigned long indicator;
+	u64 bit_nr;
+	u8 isc;
+} __packed;
+
+struct virtio_rev_info {
+	__u16 revision;
+	__u16 length;
+	__u8 data[];
+};
+
+/* the highest virtio-ccw revision we support */
+#define VIRTIO_CCW_REV_MAX 1
+
+struct virtio_ccw_vq_info {
+	struct virtqueue *vq;
+	int num;
+	void *queue;
+	union {
+		struct vq_info_block s;
+		struct vq_info_block_legacy l;
+	} *info_block;
+	int bit_nr;
+	struct list_head node;
+	long cookie;
+};
+
+#define VIRTIO_AIRQ_ISC IO_SCH_ISC /* inherit from subchannel */
+
+#define VIRTIO_IV_BITS (L1_CACHE_BYTES * 8)
+#define MAX_AIRQ_AREAS 20
+
+static int virtio_ccw_use_airq = 1;
+
+struct airq_info {
+	rwlock_t lock;
+	u8 summary_indicator;
+	struct airq_struct airq;
+	struct airq_iv *aiv;
+};
+static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
+
+#define CCW_CMD_SET_VQ 0x13
+#define CCW_CMD_VDEV_RESET 0x33
+#define CCW_CMD_SET_IND 0x43
+#define CCW_CMD_SET_CONF_IND 0x53
+#define CCW_CMD_READ_FEAT 0x12
+#define CCW_CMD_WRITE_FEAT 0x11
+#define CCW_CMD_READ_CONF 0x22
+#define CCW_CMD_WRITE_CONF 0x21
+#define CCW_CMD_WRITE_STATUS 0x31
+#define CCW_CMD_READ_VQ_CONF 0x32
+#define CCW_CMD_SET_IND_ADAPTER 0x73
+#define CCW_CMD_SET_VIRTIO_REV 0x83
+
+#define VIRTIO_CCW_DOING_SET_VQ 0x00010000
+#define VIRTIO_CCW_DOING_RESET 0x00040000
+#define VIRTIO_CCW_DOING_READ_FEAT 0x00080000
+#define VIRTIO_CCW_DOING_WRITE_FEAT 0x00100000
+#define VIRTIO_CCW_DOING_READ_CONFIG 0x00200000
+#define VIRTIO_CCW_DOING_WRITE_CONFIG 0x00400000
+#define VIRTIO_CCW_DOING_WRITE_STATUS 0x00800000
+#define VIRTIO_CCW_DOING_SET_IND 0x01000000
+#define VIRTIO_CCW_DOING_READ_VQ_CONF 0x02000000
+#define VIRTIO_CCW_DOING_SET_CONF_IND 0x04000000
+#define VIRTIO_CCW_DOING_SET_IND_ADAPTER 0x08000000
+#define VIRTIO_CCW_DOING_SET_VIRTIO_REV 0x10000000
+#define VIRTIO_CCW_INTPARM_MASK 0xffff0000
+
+static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
+{
+	return container_of(vdev, struct virtio_ccw_device, vdev);
+}
+
+static void drop_airq_indicator(struct virtqueue *vq, struct airq_info *info)
+{
+	unsigned long i, flags;
+
+	write_lock_irqsave(&info->lock, flags);
+	for (i = 0; i < airq_iv_end(info->aiv); i++) {
+		if (vq == (void *)airq_iv_get_ptr(info->aiv, i)) {
+			airq_iv_free_bit(info->aiv, i);
+			airq_iv_set_ptr(info->aiv, i, 0);
+			break;
+		}
+	}
+	write_unlock_irqrestore(&info->lock, flags);
+}
+
+static void virtio_airq_handler(struct airq_struct *airq)
+{
+	struct airq_info *info = container_of(airq, struct airq_info, airq);
+	unsigned long ai;
+
+	inc_irq_stat(IRQIO_VAI);
+	read_lock(&info->lock);
+	/* Walk through indicators field, summary indicator active. */
+	for (ai = 0;;) {
+		ai = airq_iv_scan(info->aiv, ai, airq_iv_end(info->aiv));
+		if (ai == -1UL)
+			break;
+		vring_interrupt(0, (void *)airq_iv_get_ptr(info->aiv, ai));
+	}
+	info->summary_indicator = 0;
+	smp_wmb();
+	/* Walk through indicators field, summary indicator not active. */
+	for (ai = 0;;) {
+		ai = airq_iv_scan(info->aiv, ai, airq_iv_end(info->aiv));
+		if (ai == -1UL)
+			break;
+		vring_interrupt(0, (void *)airq_iv_get_ptr(info->aiv, ai));
+	}
+	read_unlock(&info->lock);
+}
+
+static struct airq_info *new_airq_info(void)
+{
+	struct airq_info *info;
+	int rc;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return NULL;
+	rwlock_init(&info->lock);
+	info->aiv = airq_iv_create(VIRTIO_IV_BITS, AIRQ_IV_ALLOC | AIRQ_IV_PTR);
+	if (!info->aiv) {
+		kfree(info);
+		return NULL;
+	}
+	info->airq.handler = virtio_airq_handler;
+	info->airq.lsi_ptr = &info->summary_indicator;
+	info->airq.lsi_mask = 0xff;
+	info->airq.isc = VIRTIO_AIRQ_ISC;
+	rc = register_adapter_interrupt(&info->airq);
+	if (rc) {
+		airq_iv_release(info->aiv);
+		kfree(info);
+		return NULL;
+	}
+	return info;
+}
+
+static void destroy_airq_info(struct airq_info *info)
+{
+	if (!info)
+		return;
+
+	unregister_adapter_interrupt(&info->airq);
+	airq_iv_release(info->aiv);
+	kfree(info);
+}
+
+static unsigned long get_airq_indicator(struct virtqueue *vqs[], int nvqs,
+					u64 *first, void **airq_info)
+{
+	int i, j;
+	struct airq_info *info;
+	unsigned long indicator_addr = 0;
+	unsigned long bit, flags;
+
+	for (i = 0; i < MAX_AIRQ_AREAS && !indicator_addr; i++) {
+		if (!airq_areas[i])
+			airq_areas[i] = new_airq_info();
+		info = airq_areas[i];
+		if (!info)
+			return 0;
+		write_lock_irqsave(&info->lock, flags);
+		bit = airq_iv_alloc(info->aiv, nvqs);
+		if (bit == -1UL) {
+			/* Not enough vacancies. */
+			write_unlock_irqrestore(&info->lock, flags);
+			continue;
+		}
+		*first = bit;
+		*airq_info = info;
+		indicator_addr = (unsigned long)info->aiv->vector;
+		for (j = 0; j < nvqs; j++) {
+			airq_iv_set_ptr(info->aiv, bit + j,
+					(unsigned long)vqs[j]);
+		}
+		write_unlock_irqrestore(&info->lock, flags);
+	}
+	return indicator_addr;
+}
+
+static void virtio_ccw_drop_indicators(struct virtio_ccw_device *vcdev)
+{
+	struct virtio_ccw_vq_info *info;
+
+	list_for_each_entry(info, &vcdev->virtqueues, node)
+		drop_airq_indicator(info->vq, vcdev->airq_info);
+}
+
+static int doing_io(struct virtio_ccw_device *vcdev, __u32 flag)
+{
+	unsigned long flags;
+	__u32 ret;
+
+	spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
+	if (vcdev->err)
+		ret = 0;
+	else
+		ret = vcdev->curr_io & flag;
+	spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
+	return ret;
+}
+
+static int ccw_io_helper(struct virtio_ccw_device *vcdev,
+			 struct ccw1 *ccw, __u32 intparm)
+{
+	int ret;
+	unsigned long flags;
+	int flag = intparm & VIRTIO_CCW_INTPARM_MASK;
+
+	do {
+		spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
+		ret = ccw_device_start(vcdev->cdev, ccw, intparm, 0, 0);
+		if (!ret) {
+			if (!vcdev->curr_io)
+				vcdev->err = 0;
+			vcdev->curr_io |= flag;
+		}
+		spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
+		cpu_relax();
+	} while (ret == -EBUSY);
+	wait_event(vcdev->wait_q, doing_io(vcdev, flag) == 0);
+	return ret ? ret : vcdev->err;
+}
+
+static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
+				      struct ccw1 *ccw)
+{
+	int ret;
+	unsigned long *indicatorp = NULL;
+	struct virtio_thinint_area *thinint_area = NULL;
+	struct airq_info *airq_info = vcdev->airq_info;
+
+	if (vcdev->is_thinint) {
+		thinint_area = kzalloc(sizeof(*thinint_area),
+				       GFP_DMA | GFP_KERNEL);
+		if (!thinint_area)
+			return;
+		thinint_area->summary_indicator =
+			(unsigned long) &airq_info->summary_indicator;
+		thinint_area->isc = VIRTIO_AIRQ_ISC;
+		ccw->cmd_code = CCW_CMD_SET_IND_ADAPTER;
+		ccw->count = sizeof(*thinint_area);
+		ccw->cda = (__u32)(unsigned long) thinint_area;
+	} else {
+		indicatorp = kmalloc(sizeof(&vcdev->indicators),
+				     GFP_DMA | GFP_KERNEL);
+		if (!indicatorp)
+			return;
+		*indicatorp = 0;
+		ccw->cmd_code = CCW_CMD_SET_IND;
+		ccw->count = sizeof(vcdev->indicators);
+		ccw->cda = (__u32)(unsigned long) indicatorp;
+	}
+	/* Deregister indicators from host. */
+	vcdev->indicators = 0;
+	ccw->flags = 0;
+	ret = ccw_io_helper(vcdev, ccw,
+			    vcdev->is_thinint ?
+			    VIRTIO_CCW_DOING_SET_IND_ADAPTER :
+			    VIRTIO_CCW_DOING_SET_IND);
+	if (ret && (ret != -ENODEV))
+		dev_info(&vcdev->cdev->dev,
+			 "Failed to deregister indicators (%d)\n", ret);
+	else if (vcdev->is_thinint)
+		virtio_ccw_drop_indicators(vcdev);
+	kfree(indicatorp);
+	kfree(thinint_area);
+}
+
+static inline long __do_kvm_notify(struct subchannel_id schid,
+				   unsigned long queue_index,
+				   long cookie)
+{
+	register unsigned long __nr asm("1") = KVM_S390_VIRTIO_CCW_NOTIFY;
+	register struct subchannel_id __schid asm("2") = schid;
+	register unsigned long __index asm("3") = queue_index;
+	register long __rc asm("2");
+	register long __cookie asm("4") = cookie;
+
+	asm volatile ("diag 2,4,0x500\n"
+		      : "=d" (__rc) : "d" (__nr), "d" (__schid), "d" (__index),
+		      "d"(__cookie)
+		      : "memory", "cc");
+	return __rc;
+}
+
+static inline long do_kvm_notify(struct subchannel_id schid,
+				 unsigned long queue_index,
+				 long cookie)
+{
+	diag_stat_inc(DIAG_STAT_X500);
+	return __do_kvm_notify(schid, queue_index, cookie);
+}
+
+static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
+{
+	struct virtio_ccw_vq_info *info = vq->priv;
+	struct virtio_ccw_device *vcdev;
+	struct subchannel_id schid;
+
+	vcdev = to_vc_device(info->vq->vdev);
+	ccw_device_get_schid(vcdev->cdev, &schid);
+	info->cookie = do_kvm_notify(schid, vq->index, info->cookie);
+	if (info->cookie < 0)
+		return false;
+	return true;
+}
+
+static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
+				   struct ccw1 *ccw, int index)
+{
+	int ret;
+
+	vcdev->config_block->index = index;
+	ccw->cmd_code = CCW_CMD_READ_VQ_CONF;
+	ccw->flags = 0;
+	ccw->count = sizeof(struct vq_config_block);
+	ccw->cda = (__u32)(unsigned long)(vcdev->config_block);
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_VQ_CONF);
+	if (ret)
+		return ret;
+	return vcdev->config_block->num;
+}
+
+static void virtio_ccw_del_vq(struct virtqueue *vq, struct ccw1 *ccw)
+{
+	struct virtio_ccw_device *vcdev = to_vc_device(vq->vdev);
+	struct virtio_ccw_vq_info *info = vq->priv;
+	unsigned long flags;
+	unsigned long size;
+	int ret;
+	unsigned int index = vq->index;
+
+	/* Remove from our list. */
+	spin_lock_irqsave(&vcdev->lock, flags);
+	list_del(&info->node);
+	spin_unlock_irqrestore(&vcdev->lock, flags);
+
+	/* Release from host. */
+	if (vcdev->revision == 0) {
+		info->info_block->l.queue = 0;
+		info->info_block->l.align = 0;
+		info->info_block->l.index = index;
+		info->info_block->l.num = 0;
+		ccw->count = sizeof(info->info_block->l);
+	} else {
+		info->info_block->s.desc = 0;
+		info->info_block->s.index = index;
+		info->info_block->s.num = 0;
+		info->info_block->s.avail = 0;
+		info->info_block->s.used = 0;
+		ccw->count = sizeof(info->info_block->s);
+	}
+	ccw->cmd_code = CCW_CMD_SET_VQ;
+	ccw->flags = 0;
+	ccw->cda = (__u32)(unsigned long)(info->info_block);
+	ret = ccw_io_helper(vcdev, ccw,
+			    VIRTIO_CCW_DOING_SET_VQ | index);
+	/*
+	 * -ENODEV isn't considered an error: The device is gone anyway.
+	 * This may happen on device detach.
+	 */
+	if (ret && (ret != -ENODEV))
+		dev_warn(&vq->vdev->dev, "Error %d while deleting queue %d",
+			 ret, index);
+
+	vring_del_virtqueue(vq);
+	size = PAGE_ALIGN(vring_size(info->num, KVM_VIRTIO_CCW_RING_ALIGN));
+	free_pages_exact(info->queue, size);
+	kfree(info->info_block);
+	kfree(info);
+}
+
+static void virtio_ccw_del_vqs(struct virtio_device *vdev)
+{
+	struct virtqueue *vq, *n;
+	struct ccw1 *ccw;
+	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+
+	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	if (!ccw)
+		return;
+
+	virtio_ccw_drop_indicator(vcdev, ccw);
+
+	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
+		virtio_ccw_del_vq(vq, ccw);
+
+	kfree(ccw);
+}
+
+static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
+					     int i, vq_callback_t *callback,
+					     const char *name,
+					     struct ccw1 *ccw)
+{
+	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+	int err;
+	struct virtqueue *vq = NULL;
+	struct virtio_ccw_vq_info *info;
+	unsigned long size = 0; /* silence the compiler */
+	unsigned long flags;
+
+	/* Allocate queue. */
+	info = kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
+	if (!info) {
+		dev_warn(&vcdev->cdev->dev, "no info\n");
+		err = -ENOMEM;
+		goto out_err;
+	}
+	info->info_block = kzalloc(sizeof(*info->info_block),
+				   GFP_DMA | GFP_KERNEL);
+	if (!info->info_block) {
+		dev_warn(&vcdev->cdev->dev, "no info block\n");
+		err = -ENOMEM;
+		goto out_err;
+	}
+	info->num = virtio_ccw_read_vq_conf(vcdev, ccw, i);
+	if (info->num < 0) {
+		err = info->num;
+		goto out_err;
+	}
+	size = PAGE_ALIGN(vring_size(info->num, KVM_VIRTIO_CCW_RING_ALIGN));
+	info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
+	if (info->queue == NULL) {
+		dev_warn(&vcdev->cdev->dev, "no queue\n");
+		err = -ENOMEM;
+		goto out_err;
+	}
+
+	vq = vring_new_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN, vdev,
+				 true, info->queue, virtio_ccw_kvm_notify,
+				 callback, name);
+	if (!vq) {
+		/* For now, we fail if we can't get the requested size. */
+		dev_warn(&vcdev->cdev->dev, "no vq\n");
+		err = -ENOMEM;
+		goto out_err;
+	}
+
+	/* Register it with the host. */
+	if (vcdev->revision == 0) {
+		info->info_block->l.queue = (__u64)info->queue;
+		info->info_block->l.align = KVM_VIRTIO_CCW_RING_ALIGN;
+		info->info_block->l.index = i;
+		info->info_block->l.num = info->num;
+		ccw->count = sizeof(info->info_block->l);
+	} else {
+		info->info_block->s.desc = (__u64)info->queue;
+		info->info_block->s.index = i;
+		info->info_block->s.num = info->num;
+		info->info_block->s.avail = (__u64)virtqueue_get_avail(vq);
+		info->info_block->s.used = (__u64)virtqueue_get_used(vq);
+		ccw->count = sizeof(info->info_block->s);
+	}
+	ccw->cmd_code = CCW_CMD_SET_VQ;
+	ccw->flags = 0;
+	ccw->cda = (__u32)(unsigned long)(info->info_block);
+	err = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_VQ | i);
+	if (err) {
+		dev_warn(&vcdev->cdev->dev, "SET_VQ failed\n");
+		goto out_err;
+	}
+
+	info->vq = vq;
+	vq->priv = info;
+
+	/* Save it to our list. */
+	spin_lock_irqsave(&vcdev->lock, flags);
+	list_add(&info->node, &vcdev->virtqueues);
+	spin_unlock_irqrestore(&vcdev->lock, flags);
+
+	return vq;
+
+out_err:
+	if (vq)
+		vring_del_virtqueue(vq);
+	if (info) {
+		if (info->queue)
+			free_pages_exact(info->queue, size);
+		kfree(info->info_block);
+	}
+	kfree(info);
+	return ERR_PTR(err);
+}
+
+static int virtio_ccw_register_adapter_ind(struct virtio_ccw_device *vcdev,
+					   struct virtqueue *vqs[], int nvqs,
+					   struct ccw1 *ccw)
+{
+	int ret;
+	struct virtio_thinint_area *thinint_area = NULL;
+	struct airq_info *info;
+
+	thinint_area = kzalloc(sizeof(*thinint_area), GFP_DMA | GFP_KERNEL);
+	if (!thinint_area) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	/* Try to get an indicator. */
+	thinint_area->indicator = get_airq_indicator(vqs, nvqs,
+						     &thinint_area->bit_nr,
+						     &vcdev->airq_info);
+	if (!thinint_area->indicator) {
+		ret = -ENOSPC;
+		goto out;
+	}
+	info = vcdev->airq_info;
+	thinint_area->summary_indicator =
+		(unsigned long) &info->summary_indicator;
+	thinint_area->isc = VIRTIO_AIRQ_ISC;
+	ccw->cmd_code = CCW_CMD_SET_IND_ADAPTER;
+	ccw->flags = CCW_FLAG_SLI;
+	ccw->count = sizeof(*thinint_area);
+	ccw->cda = (__u32)(unsigned long)thinint_area;
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_IND_ADAPTER);
+	if (ret) {
+		if (ret == -EOPNOTSUPP) {
+			/*
+			 * The host does not support adapter interrupts
+			 * for virtio-ccw, stop trying.
+			 */
+			virtio_ccw_use_airq = 0;
+			pr_info("Adapter interrupts unsupported on host\n");
+		} else
+			dev_warn(&vcdev->cdev->dev,
+				 "enabling adapter interrupts = %d\n", ret);
+		virtio_ccw_drop_indicators(vcdev);
+	}
+out:
+	kfree(thinint_area);
+	return ret;
+}
+
+static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
+			       struct virtqueue *vqs[],
+			       vq_callback_t *callbacks[],
+			       const char *names[])
+{
+	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+	unsigned long *indicatorp = NULL;
+	int ret, i;
+	struct ccw1 *ccw;
+
+	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	if (!ccw)
+		return -ENOMEM;
+
+	for (i = 0; i < nvqs; ++i) {
+		vqs[i] = virtio_ccw_setup_vq(vdev, i, callbacks[i], names[i],
+					     ccw);
+		if (IS_ERR(vqs[i])) {
+			ret = PTR_ERR(vqs[i]);
+			vqs[i] = NULL;
+			goto out;
+		}
+	}
+	ret = -ENOMEM;
+	/* We need a data area under 2G to communicate. */
+	indicatorp = kmalloc(sizeof(&vcdev->indicators), GFP_DMA | GFP_KERNEL);
+	if (!indicatorp)
+		goto out;
+	*indicatorp = (unsigned long) &vcdev->indicators;
+	if (vcdev->is_thinint) {
+		ret = virtio_ccw_register_adapter_ind(vcdev, vqs, nvqs, ccw);
+		if (ret)
+			/* no error, just fall back to legacy interrupts */
+			vcdev->is_thinint = 0;
+	}
+	if (!vcdev->is_thinint) {
+		/* Register queue indicators with host. */
+		vcdev->indicators = 0;
+		ccw->cmd_code = CCW_CMD_SET_IND;
+		ccw->flags = 0;
+		ccw->count = sizeof(vcdev->indicators);
+		ccw->cda = (__u32)(unsigned long) indicatorp;
+		ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_IND);
+		if (ret)
+			goto out;
+	}
+	/* Register indicators2 with host for config changes */
+	*indicatorp = (unsigned long) &vcdev->indicators2;
+	vcdev->indicators2 = 0;
+	ccw->cmd_code = CCW_CMD_SET_CONF_IND;
+	ccw->flags = 0;
+	ccw->count = sizeof(vcdev->indicators2);
+	ccw->cda = (__u32)(unsigned long) indicatorp;
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_CONF_IND);
+	if (ret)
+		goto out;
+
+	kfree(indicatorp);
+	kfree(ccw);
+	return 0;
+out:
+	kfree(indicatorp);
+	kfree(ccw);
+	virtio_ccw_del_vqs(vdev);
+	return ret;
+}
+
+static void virtio_ccw_reset(struct virtio_device *vdev)
+{
+	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+	struct ccw1 *ccw;
+
+	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	if (!ccw)
+		return;
+
+	/* Zero status bits. */
+	*vcdev->status = 0;
+
+	/* Send a reset ccw on device. */
+	ccw->cmd_code = CCW_CMD_VDEV_RESET;
+	ccw->flags = 0;
+	ccw->count = 0;
+	ccw->cda = 0;
+	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_RESET);
+	kfree(ccw);
+}
+
+static u64 virtio_ccw_get_features(struct virtio_device *vdev)
+{
+	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+	struct virtio_feature_desc *features;
+	int ret;
+	u64 rc;
+	struct ccw1 *ccw;
+
+	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	if (!ccw)
+		return 0;
+
+	features = kzalloc(sizeof(*features), GFP_DMA | GFP_KERNEL);
+	if (!features) {
+		rc = 0;
+		goto out_free;
+	}
+	/* Read the feature bits from the host. */
+	features->index = 0;
+	ccw->cmd_code = CCW_CMD_READ_FEAT;
+	ccw->flags = 0;
+	ccw->count = sizeof(*features);
+	ccw->cda = (__u32)(unsigned long)features;
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_FEAT);
+	if (ret) {
+		rc = 0;
+		goto out_free;
+	}
+
+	rc = le32_to_cpu(features->features);
+
+	if (vcdev->revision == 0)
+		goto out_free;
+
+	/* Read second half of the feature bits from the host. */
+	features->index = 1;
+	ccw->cmd_code = CCW_CMD_READ_FEAT;
+	ccw->flags = 0;
+	ccw->count = sizeof(*features);
+	ccw->cda = (__u32)(unsigned long)features;
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_FEAT);
+	if (ret == 0)
+		rc |= (u64)le32_to_cpu(features->features) << 32;
+
+out_free:
+	kfree(features);
+	kfree(ccw);
+	return rc;
+}
+
+static int virtio_ccw_finalize_features(struct virtio_device *vdev)
+{
+	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+	struct virtio_feature_desc *features;
+	struct ccw1 *ccw;
+	int ret;
+
+	if (vcdev->revision >= 1 &&
+	    !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
+		dev_err(&vdev->dev, "virtio: device uses revision 1 "
+			"but does not have VIRTIO_F_VERSION_1\n");
+		return -EINVAL;
+	}
+
+	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	if (!ccw)
+		return -ENOMEM;
+
+	features = kzalloc(sizeof(*features), GFP_DMA | GFP_KERNEL);
+	if (!features) {
+		ret = -ENOMEM;
+		goto out_free;
+	}
+	/* Give virtio_ring a chance to accept features. */
+	vring_transport_features(vdev);
+
+	features->index = 0;
+	features->features = cpu_to_le32((u32)vdev->features);
+	/* Write the first half of the feature bits to the host. */
+	ccw->cmd_code = CCW_CMD_WRITE_FEAT;
+	ccw->flags = 0;
+	ccw->count = sizeof(*features);
+	ccw->cda = (__u32)(unsigned long)features;
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
+	if (ret)
+		goto out_free;
+
+	if (vcdev->revision == 0)
+		goto out_free;
+
+	features->index = 1;
+	features->features = cpu_to_le32(vdev->features >> 32);
+	/* Write the second half of the feature bits to the host. */
+	ccw->cmd_code = CCW_CMD_WRITE_FEAT;
+	ccw->flags = 0;
+	ccw->count = sizeof(*features);
+	ccw->cda = (__u32)(unsigned long)features;
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
+
+out_free:
+	kfree(features);
+	kfree(ccw);
+
+	return ret;
+}
+
+static void virtio_ccw_get_config(struct virtio_device *vdev,
+				  unsigned int offset, void *buf, unsigned len)
+{
+	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+	int ret;
+	struct ccw1 *ccw;
+	void *config_area;
+
+	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	if (!ccw)
+		return;
+
+	config_area = kzalloc(VIRTIO_CCW_CONFIG_SIZE, GFP_DMA | GFP_KERNEL);
+	if (!config_area)
+		goto out_free;
+
+	/* Read the config area from the host. */
+	ccw->cmd_code = CCW_CMD_READ_CONF;
+	ccw->flags = 0;
+	ccw->count = offset + len;
+	ccw->cda = (__u32)(unsigned long)config_area;
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_CONFIG);
+	if (ret)
+		goto out_free;
+
+	memcpy(vcdev->config, config_area, offset + len);
+	if (buf)
+		memcpy(buf, &vcdev->config[offset], len);
+	if (vcdev->config_ready < offset + len)
+		vcdev->config_ready = offset + len;
+
+out_free:
+	kfree(config_area);
+	kfree(ccw);
+}
+
+static void virtio_ccw_set_config(struct virtio_device *vdev,
+				  unsigned int offset, const void *buf,
+				  unsigned len)
+{
+	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+	struct ccw1 *ccw;
+	void *config_area;
+
+	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	if (!ccw)
+		return;
+
+	config_area = kzalloc(VIRTIO_CCW_CONFIG_SIZE, GFP_DMA | GFP_KERNEL);
+	if (!config_area)
+		goto out_free;
+
+	/* Make sure we don't overwrite fields. */
+	if (vcdev->config_ready < offset)
+		virtio_ccw_get_config(vdev, 0, NULL, offset);
+	memcpy(&vcdev->config[offset], buf, len);
+	/* Write the config area to the host. */
+	memcpy(config_area, vcdev->config, sizeof(vcdev->config));
+	ccw->cmd_code = CCW_CMD_WRITE_CONF;
+	ccw->flags = 0;
+	ccw->count = offset + len;
+	ccw->cda = (__u32)(unsigned long)config_area;
+	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_CONFIG);
+
+out_free:
+	kfree(config_area);
+	kfree(ccw);
+}
+
+static u8 virtio_ccw_get_status(struct virtio_device *vdev)
+{
+	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+
+	return *vcdev->status;
+}
+
+static void virtio_ccw_set_status(struct virtio_device *vdev, u8 status)
+{
+	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+	u8 old_status = *vcdev->status;
+	struct ccw1 *ccw;
+	int ret;
+
+	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	if (!ccw)
+		return;
+
+	/* Write the status to the host. */
+	*vcdev->status = status;
+	ccw->cmd_code = CCW_CMD_WRITE_STATUS;
+	ccw->flags = 0;
+	ccw->count = sizeof(status);
+	ccw->cda = (__u32)(unsigned long)vcdev->status;
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_STATUS);
+	/* Write failed? We assume status is unchanged. */
+	if (ret)
+		*vcdev->status = old_status;
+	kfree(ccw);
+}
+
+static struct virtio_config_ops virtio_ccw_config_ops = {
+	.get_features = virtio_ccw_get_features,
+	.finalize_features = virtio_ccw_finalize_features,
+	.get = virtio_ccw_get_config,
+	.set = virtio_ccw_set_config,
+	.get_status = virtio_ccw_get_status,
+	.set_status = virtio_ccw_set_status,
+	.reset = virtio_ccw_reset,
+	.find_vqs = virtio_ccw_find_vqs,
+	.del_vqs = virtio_ccw_del_vqs,
+};
+
+
+/*
+ * ccw bus driver related functions
+ */
+
+static void virtio_ccw_release_dev(struct device *_d)
+{
+	struct virtio_device *dev = container_of(_d, struct virtio_device,
+						 dev);
+	struct virtio_ccw_device *vcdev = to_vc_device(dev);
+
+	kfree(vcdev->status);
+	kfree(vcdev->config_block);
+	kfree(vcdev);
+}
+
+static int irb_is_error(struct irb *irb)
+{
+	if (scsw_cstat(&irb->scsw) != 0)
+		return 1;
+	if (scsw_dstat(&irb->scsw) & ~(DEV_STAT_CHN_END | DEV_STAT_DEV_END))
+		return 1;
+	if (scsw_cc(&irb->scsw) != 0)
+		return 1;
+	return 0;
+}
+
+static struct virtqueue *virtio_ccw_vq_by_ind(struct virtio_ccw_device *vcdev,
+					      int index)
+{
+	struct virtio_ccw_vq_info *info;
+	unsigned long flags;
+	struct virtqueue *vq;
+
+	vq = NULL;
+	spin_lock_irqsave(&vcdev->lock, flags);
+	list_for_each_entry(info, &vcdev->virtqueues, node) {
+		if (info->vq->index == index) {
+			vq = info->vq;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&vcdev->lock, flags);
+	return vq;
+}
+
+static void virtio_ccw_check_activity(struct virtio_ccw_device *vcdev,
+				      __u32 activity)
+{
+	if (vcdev->curr_io & activity) {
+		switch (activity) {
+		case VIRTIO_CCW_DOING_READ_FEAT:
+		case VIRTIO_CCW_DOING_WRITE_FEAT:
+		case VIRTIO_CCW_DOING_READ_CONFIG:
+		case VIRTIO_CCW_DOING_WRITE_CONFIG:
+		case VIRTIO_CCW_DOING_WRITE_STATUS:
+		case VIRTIO_CCW_DOING_SET_VQ:
+		case VIRTIO_CCW_DOING_SET_IND:
+		case VIRTIO_CCW_DOING_SET_CONF_IND:
+		case VIRTIO_CCW_DOING_RESET:
+		case VIRTIO_CCW_DOING_READ_VQ_CONF:
+		case VIRTIO_CCW_DOING_SET_IND_ADAPTER:
+		case VIRTIO_CCW_DOING_SET_VIRTIO_REV:
+			vcdev->curr_io &= ~activity;
+			wake_up(&vcdev->wait_q);
+			break;
+		default:
+			/* don't know what to do... */
+			dev_warn(&vcdev->cdev->dev,
+				 "Suspicious activity '%08x'\n", activity);
+			WARN_ON(1);
+			break;
+		}
+	}
+}
+
+static void virtio_ccw_int_handler(struct ccw_device *cdev,
+				   unsigned long intparm,
+				   struct irb *irb)
+{
+	__u32 activity = intparm & VIRTIO_CCW_INTPARM_MASK;
+	struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev);
+	int i;
+	struct virtqueue *vq;
+
+	if (!vcdev)
+		return;
+	if (IS_ERR(irb)) {
+		vcdev->err = PTR_ERR(irb);
+		virtio_ccw_check_activity(vcdev, activity);
+		/* Don't poke around indicators, something's wrong. */
+		return;
+	}
+	/* Check if it's a notification from the host. */
+	if ((intparm == 0) &&
+	    (scsw_stctl(&irb->scsw) ==
+	     (SCSW_STCTL_ALERT_STATUS | SCSW_STCTL_STATUS_PEND))) {
+		/* OK */
+	}
+	if (irb_is_error(irb)) {
+		/* Command reject? */
+		if ((scsw_dstat(&irb->scsw) & DEV_STAT_UNIT_CHECK) &&
+		    (irb->ecw[0] & SNS0_CMD_REJECT))
+			vcdev->err = -EOPNOTSUPP;
+		else
+			/* Map everything else to -EIO. */
+			vcdev->err = -EIO;
+	}
+	virtio_ccw_check_activity(vcdev, activity);
+	for_each_set_bit(i, &vcdev->indicators,
+			 sizeof(vcdev->indicators) * BITS_PER_BYTE) {
+		/* The bit clear must happen before the vring kick. */
+		clear_bit(i, &vcdev->indicators);
+		barrier();
+		vq = virtio_ccw_vq_by_ind(vcdev, i);
+		vring_interrupt(0, vq);
+	}
+	if (test_bit(0, &vcdev->indicators2)) {
+		virtio_config_changed(&vcdev->vdev);
+		clear_bit(0, &vcdev->indicators2);
+	}
+}
+
+/*
+ * We usually want to autoonline all devices, but give the admin
+ * a way to exempt devices from this.
+ */
+#define __DEV_WORDS ((__MAX_SUBCHANNEL + (8*sizeof(long) - 1)) / \
+		     (8*sizeof(long)))
+static unsigned long devs_no_auto[__MAX_SSID + 1][__DEV_WORDS];
+
+static char *no_auto = "";
+
+module_param(no_auto, charp, 0444);
+MODULE_PARM_DESC(no_auto, "list of ccw bus id ranges not to be auto-onlined");
+
+static int virtio_ccw_check_autoonline(struct ccw_device *cdev)
+{
+	struct ccw_dev_id id;
+
+	ccw_device_get_id(cdev, &id);
+	if (test_bit(id.devno, devs_no_auto[id.ssid]))
+		return 0;
+	return 1;
+}
+
+static void virtio_ccw_auto_online(void *data, async_cookie_t cookie)
+{
+	struct ccw_device *cdev = data;
+	int ret;
+
+	ret = ccw_device_set_online(cdev);
+	if (ret)
+		dev_warn(&cdev->dev, "Failed to set online: %d\n", ret);
+}
+
+static int virtio_ccw_probe(struct ccw_device *cdev)
+{
+	cdev->handler = virtio_ccw_int_handler;
+
+	if (virtio_ccw_check_autoonline(cdev))
+		async_schedule(virtio_ccw_auto_online, cdev);
+	return 0;
+}
+
+static struct virtio_ccw_device *virtio_grab_drvdata(struct ccw_device *cdev)
+{
+	unsigned long flags;
+	struct virtio_ccw_device *vcdev;
+
+	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
+	vcdev = dev_get_drvdata(&cdev->dev);
+	if (!vcdev || vcdev->going_away) {
+		spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
+		return NULL;
+	}
+	vcdev->going_away = true;
+	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
+	return vcdev;
+}
+
+static void virtio_ccw_remove(struct ccw_device *cdev)
+{
+	unsigned long flags;
+	struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev);
+
+	if (vcdev && cdev->online) {
+		if (vcdev->device_lost)
+			virtio_break_device(&vcdev->vdev);
+		unregister_virtio_device(&vcdev->vdev);
+		spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
+		dev_set_drvdata(&cdev->dev, NULL);
+		spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
+	}
+	cdev->handler = NULL;
+}
+
+static int virtio_ccw_offline(struct ccw_device *cdev)
+{
+	unsigned long flags;
+	struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev);
+
+	if (!vcdev)
+		return 0;
+	if (vcdev->device_lost)
+		virtio_break_device(&vcdev->vdev);
+	unregister_virtio_device(&vcdev->vdev);
+	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
+	dev_set_drvdata(&cdev->dev, NULL);
+	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
+	return 0;
+}
+
+static int virtio_ccw_set_transport_rev(struct virtio_ccw_device *vcdev)
+{
+	struct virtio_rev_info *rev;
+	struct ccw1 *ccw;
+	int ret;
+
+	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	if (!ccw)
+		return -ENOMEM;
+	rev = kzalloc(sizeof(*rev), GFP_DMA | GFP_KERNEL);
+	if (!rev) {
+		kfree(ccw);
+		return -ENOMEM;
+	}
+
+	/* Set transport revision */
+	ccw->cmd_code = CCW_CMD_SET_VIRTIO_REV;
+	ccw->flags = 0;
+	ccw->count = sizeof(*rev);
+	ccw->cda = (__u32)(unsigned long)rev;
+
+	vcdev->revision = VIRTIO_CCW_REV_MAX;
+	do {
+		rev->revision = vcdev->revision;
+		/* none of our supported revisions carry payload */
+		rev->length = 0;
+		ret = ccw_io_helper(vcdev, ccw,
+				    VIRTIO_CCW_DOING_SET_VIRTIO_REV);
+		if (ret == -EOPNOTSUPP) {
+			if (vcdev->revision == 0)
+				/*
+				 * The host device does not support setting
+				 * the revision: let's operate it in legacy
+				 * mode.
+				 */
+				ret = 0;
+			else
+				vcdev->revision--;
+		}
+	} while (ret == -EOPNOTSUPP);
+
+	kfree(ccw);
+	kfree(rev);
+	return ret;
+}
+
+static int virtio_ccw_online(struct ccw_device *cdev)
+{
+	int ret;
+	struct virtio_ccw_device *vcdev;
+	unsigned long flags;
+
+	vcdev = kzalloc(sizeof(*vcdev), GFP_KERNEL);
+	if (!vcdev) {
+		dev_warn(&cdev->dev, "Could not get memory for virtio\n");
+		ret = -ENOMEM;
+		goto out_free;
+	}
+	vcdev->config_block = kzalloc(sizeof(*vcdev->config_block),
+				   GFP_DMA | GFP_KERNEL);
+	if (!vcdev->config_block) {
+		ret = -ENOMEM;
+		goto out_free;
+	}
+	vcdev->status = kzalloc(sizeof(*vcdev->status), GFP_DMA | GFP_KERNEL);
+	if (!vcdev->status) {
+		ret = -ENOMEM;
+		goto out_free;
+	}
+
+	vcdev->is_thinint = virtio_ccw_use_airq; /* at least try */
+
+	vcdev->vdev.dev.parent = &cdev->dev;
+	vcdev->vdev.dev.release = virtio_ccw_release_dev;
+	vcdev->vdev.config = &virtio_ccw_config_ops;
+	vcdev->cdev = cdev;
+	init_waitqueue_head(&vcdev->wait_q);
+	INIT_LIST_HEAD(&vcdev->virtqueues);
+	spin_lock_init(&vcdev->lock);
+
+	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
+	dev_set_drvdata(&cdev->dev, vcdev);
+	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
+	vcdev->vdev.id.vendor = cdev->id.cu_type;
+	vcdev->vdev.id.device = cdev->id.cu_model;
+
+	ret = virtio_ccw_set_transport_rev(vcdev);
+	if (ret)
+		goto out_free;
+
+	ret = register_virtio_device(&vcdev->vdev);
+	if (ret) {
+		dev_warn(&cdev->dev, "Failed to register virtio device: %d\n",
+			 ret);
+		goto out_put;
+	}
+	return 0;
+out_put:
+	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
+	dev_set_drvdata(&cdev->dev, NULL);
+	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
+	put_device(&vcdev->vdev.dev);
+	return ret;
+out_free:
+	if (vcdev) {
+		kfree(vcdev->status);
+		kfree(vcdev->config_block);
+	}
+	kfree(vcdev);
+	return ret;
+}
+
+static int virtio_ccw_cio_notify(struct ccw_device *cdev, int event)
+{
+	int rc;
+	struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev);
+
+	/*
+	 * Make sure vcdev is set
+	 * i.e. set_offline/remove callback not already running
+	 */
+	if (!vcdev)
+		return NOTIFY_DONE;
+
+	switch (event) {
+	case CIO_GONE:
+		vcdev->device_lost = true;
+		rc = NOTIFY_DONE;
+		break;
+	default:
+		rc = NOTIFY_DONE;
+		break;
+	}
+	return rc;
+}
+
+static struct ccw_device_id virtio_ids[] = {
+	{ CCW_DEVICE(0x3832, 0) },
+	{},
+};
+MODULE_DEVICE_TABLE(ccw, virtio_ids);
+
+static struct ccw_driver virtio_ccw_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = "virtio_ccw",
+	},
+	.ids = virtio_ids,
+	.probe = virtio_ccw_probe,
+	.remove = virtio_ccw_remove,
+	.set_offline = virtio_ccw_offline,
+	.set_online = virtio_ccw_online,
+	.notify = virtio_ccw_cio_notify,
+	.int_class = IRQIO_VIR,
+};
+
+static int __init pure_hex(char **cp, unsigned int *val, int min_digit,
+			   int max_digit, int max_val)
+{
+	int diff;
+
+	diff = 0;
+	*val = 0;
+
+	while (diff <= max_digit) {
+		int value = hex_to_bin(**cp);
+
+		if (value < 0)
+			break;
+		*val = *val * 16 + value;
+		(*cp)++;
+		diff++;
+	}
+
+	if ((diff < min_digit) || (diff > max_digit) || (*val > max_val))
+		return 1;
+
+	return 0;
+}
+
+static int __init parse_busid(char *str, unsigned int *cssid,
+			      unsigned int *ssid, unsigned int *devno)
+{
+	char *str_work;
+	int rc, ret;
+
+	rc = 1;
+
+	if (*str == '\0')
+		goto out;
+
+	str_work = str;
+	ret = pure_hex(&str_work, cssid, 1, 2, __MAX_CSSID);
+	if (ret || (str_work[0] != '.'))
+		goto out;
+	str_work++;
+	ret = pure_hex(&str_work, ssid, 1, 1, __MAX_SSID);
+	if (ret || (str_work[0] != '.'))
+		goto out;
+	str_work++;
+	ret = pure_hex(&str_work, devno, 4, 4, __MAX_SUBCHANNEL);
+	if (ret || (str_work[0] != '\0'))
+		goto out;
+
+	rc = 0;
+out:
+	return rc;
+}
+
+static void __init no_auto_parse(void)
+{
+	unsigned int from_cssid, to_cssid, from_ssid, to_ssid, from, to;
+	char *parm, *str;
+	int rc;
+
+	str = no_auto;
+	while ((parm = strsep(&str, ","))) {
+		rc = parse_busid(strsep(&parm, "-"), &from_cssid,
+				 &from_ssid, &from);
+		if (rc)
+			continue;
+		if (parm != NULL) {
+			rc = parse_busid(parm, &to_cssid,
+					 &to_ssid, &to);
+			if ((from_ssid > to_ssid) ||
+			    ((from_ssid == to_ssid) && (from > to)))
+				rc = -EINVAL;
+		} else {
+			to_cssid = from_cssid;
+			to_ssid = from_ssid;
+			to = from;
+		}
+		if (rc)
+			continue;
+		while ((from_ssid < to_ssid) ||
+		       ((from_ssid == to_ssid) && (from <= to))) {
+			set_bit(from, devs_no_auto[from_ssid]);
+			from++;
+			if (from > __MAX_SUBCHANNEL) {
+				from_ssid++;
+				from = 0;
+			}
+		}
+	}
+}
+
+static int __init virtio_ccw_init(void)
+{
+	/* parse no_auto string before we do anything further */
+	no_auto_parse();
+	return ccw_driver_register(&virtio_ccw_driver);
+}
+module_init(virtio_ccw_init);
+
+static void __exit virtio_ccw_exit(void)
+{
+	int i;
+
+	ccw_driver_unregister(&virtio_ccw_driver);
+	for (i = 0; i < MAX_AIRQ_AREAS; i++)
+		destroy_airq_info(airq_areas[i]);
+}
+module_exit(virtio_ccw_exit);