linux-stable/drivers/s390/crypto/zcrypt_api.c

/*
 *  zcrypt 2.1.0
 *
 *  Copyright IBM Corp. 2001, 2012
 *  Author(s): Robert Burroughs
 *	       Eric Rossman (edrossma@us.ibm.com)
 *	       Cornelia Huck <cornelia.huck@de.ibm.com>
 *
 *  Hotplug & misc device support: Jochen Roehrig (roehrig@de.ibm.com)
 *  Major cleanup & driver split: Martin Schwidefsky <schwidefsky@de.ibm.com>
 *				  Ralph Wuerthner <rwuerthn@de.ibm.com>
 *  MSGTYPE restruct:		  Holger Dengler <hd@linux.vnet.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/compat.h>
#include <linux/slab.h>
#include <linux/atomic.h>
#include <asm/uaccess.h>
#include <linux/hw_random.h>
#include <linux/debugfs.h>
#include <asm/debug.h>

#include "zcrypt_debug.h"
#include "zcrypt_api.h"

#include "zcrypt_msgtype6.h"

/*
 * Module description.
 */
MODULE_AUTHOR("IBM Corporation");
MODULE_DESCRIPTION("Cryptographic Coprocessor interface, " \
		   "Copyright IBM Corp. 2001, 2012");
MODULE_LICENSE("GPL");

static int zcrypt_hwrng_seed = 1;
module_param_named(hwrng_seed, zcrypt_hwrng_seed, int, S_IRUSR|S_IRGRP);
MODULE_PARM_DESC(hwrng_seed, "Turn on/off hwrng auto seed, default is 1 (on).");

static DEFINE_SPINLOCK(zcrypt_device_lock);
static LIST_HEAD(zcrypt_device_list);
static int zcrypt_device_count = 0;
static atomic_t zcrypt_open_count = ATOMIC_INIT(0);
static atomic_t zcrypt_rescan_count = ATOMIC_INIT(0);

atomic_t zcrypt_rescan_req = ATOMIC_INIT(0);
EXPORT_SYMBOL(zcrypt_rescan_req);

static int zcrypt_rng_device_add(void);
static void zcrypt_rng_device_remove(void);

static DEFINE_SPINLOCK(zcrypt_ops_list_lock);
static LIST_HEAD(zcrypt_ops_list);

static debug_info_t *zcrypt_dbf_common;
static debug_info_t *zcrypt_dbf_devices;
static struct dentry *debugfs_root;

/*
 * Device attributes common for all crypto devices.
 */
static ssize_t zcrypt_type_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct zcrypt_device *zdev = to_ap_dev(dev)->private;
	return snprintf(buf, PAGE_SIZE, "%s\n", zdev->type_string);
}

static DEVICE_ATTR(type, 0444, zcrypt_type_show, NULL);

static ssize_t zcrypt_online_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct zcrypt_device *zdev = to_ap_dev(dev)->private;
	return snprintf(buf, PAGE_SIZE, "%d\n", zdev->online);
}

static ssize_t zcrypt_online_store(struct device *dev,
				   struct device_attribute *attr,
				   const char *buf, size_t count)
{
	struct zcrypt_device *zdev = to_ap_dev(dev)->private;
	int online;

	if (sscanf(buf, "%d\n", &online) != 1 || online < 0 || online > 1)
		return -EINVAL;
	zdev->online = online;
	ZCRYPT_DBF_DEV(DBF_INFO, zdev, "dev%04xo%dman", zdev->ap_dev->qid,
		       zdev->online);
	if (!online)
		ap_flush_queue(zdev->ap_dev);
	return count;
}

static DEVICE_ATTR(online, 0644, zcrypt_online_show, zcrypt_online_store);

static struct attribute * zcrypt_device_attrs[] = {
	&dev_attr_type.attr,
	&dev_attr_online.attr,
	NULL,
};

static struct attribute_group zcrypt_device_attr_group = {
	.attrs = zcrypt_device_attrs,
};

/**
 * Process a rescan of the transport layer.
 *
 * Returns 1, if the rescan has been processed, otherwise 0.
 */
static inline int zcrypt_process_rescan(void)
{
	if (atomic_read(&zcrypt_rescan_req)) {
		atomic_set(&zcrypt_rescan_req, 0);
		atomic_inc(&zcrypt_rescan_count);
		ap_bus_force_rescan();
		ZCRYPT_DBF_COMMON(DBF_INFO, "rescan%07d",
				  atomic_inc_return(&zcrypt_rescan_count));
		return 1;
	}
	return 0;
}

/**
 * __zcrypt_increase_preference(): Increase preference of a crypto device.
 * @zdev: Pointer the crypto device
 *
 * Move the device towards the head of the device list.
 * Need to be called while holding the zcrypt device list lock.
 * Note: cards with speed_rating of 0 are kept at the end of the list.
 */
static void __zcrypt_increase_preference(struct zcrypt_device *zdev)
{
	struct zcrypt_device *tmp;
	struct list_head *l;

	if (zdev->speed_rating == 0)
		return;
	for (l = zdev->list.prev; l != &zcrypt_device_list; l = l->prev) {
		tmp = list_entry(l, struct zcrypt_device, list);
		if ((tmp->request_count + 1) * tmp->speed_rating <=
		    (zdev->request_count + 1) * zdev->speed_rating &&
		    tmp->speed_rating != 0)
			break;
	}
	if (l == zdev->list.prev)
		return;
	/* Move zdev behind l */
	list_move(&zdev->list, l);
}

/**
 * __zcrypt_decrease_preference(): Decrease preference of a crypto device.
 * @zdev: Pointer to a crypto device.
 *
 * Move the device towards the tail of the device list.
 * Need to be called while holding the zcrypt device list lock.
 * Note: cards with speed_rating of 0 are kept at the end of the list.
 */
static void __zcrypt_decrease_preference(struct zcrypt_device *zdev)
{
	struct zcrypt_device *tmp;
	struct list_head *l;

	if (zdev->speed_rating == 0)
		return;
	for (l = zdev->list.next; l != &zcrypt_device_list; l = l->next) {
		tmp = list_entry(l, struct zcrypt_device, list);
		if ((tmp->request_count + 1) * tmp->speed_rating >
		    (zdev->request_count + 1) * zdev->speed_rating ||
		    tmp->speed_rating == 0)
			break;
	}
	if (l == zdev->list.next)
		return;
	/* Move zdev before l */
	list_move_tail(&zdev->list, l);
}

static void zcrypt_device_release(struct kref *kref)
{
	struct zcrypt_device *zdev =
		container_of(kref, struct zcrypt_device, refcount);
	zcrypt_device_free(zdev);
}

void zcrypt_device_get(struct zcrypt_device *zdev)
{
	kref_get(&zdev->refcount);
}
EXPORT_SYMBOL(zcrypt_device_get);

int zcrypt_device_put(struct zcrypt_device *zdev)
{
	return kref_put(&zdev->refcount, zcrypt_device_release);
}
EXPORT_SYMBOL(zcrypt_device_put);

struct zcrypt_device *zcrypt_device_alloc(size_t max_response_size)
{
	struct zcrypt_device *zdev;

	zdev = kzalloc(sizeof(struct zcrypt_device), GFP_KERNEL);
	if (!zdev)
		return NULL;
	zdev->reply.message = kmalloc(max_response_size, GFP_KERNEL);
	if (!zdev->reply.message)
		goto out_free;
	zdev->reply.length = max_response_size;
	spin_lock_init(&zdev->lock);
	INIT_LIST_HEAD(&zdev->list);
	zdev->dbf_area = zcrypt_dbf_devices;
	return zdev;

out_free:
	kfree(zdev);
	return NULL;
}
EXPORT_SYMBOL(zcrypt_device_alloc);

void zcrypt_device_free(struct zcrypt_device *zdev)
{
	kfree(zdev->reply.message);
	kfree(zdev);
}
EXPORT_SYMBOL(zcrypt_device_free);

/**
 * zcrypt_device_register() - Register a crypto device.
 * @zdev: Pointer to a crypto device
 *
 * Register a crypto device. Returns 0 if successful.
 */
int zcrypt_device_register(struct zcrypt_device *zdev)
{
	int rc;

	if (!zdev->ops)
		return -ENODEV;
	rc = sysfs_create_group(&zdev->ap_dev->device.kobj,
				&zcrypt_device_attr_group);
	if (rc)
		goto out;
	get_device(&zdev->ap_dev->device);
	kref_init(&zdev->refcount);
	spin_lock_bh(&zcrypt_device_lock);
	zdev->online = 1;	/* New devices are online by default. */
	ZCRYPT_DBF_DEV(DBF_INFO, zdev, "dev%04xo%dreg", zdev->ap_dev->qid,
		       zdev->online);
	list_add_tail(&zdev->list, &zcrypt_device_list);
	__zcrypt_increase_preference(zdev);
	zcrypt_device_count++;
	spin_unlock_bh(&zcrypt_device_lock);
	if (zdev->ops->rng) {
		rc = zcrypt_rng_device_add();
		if (rc)
			goto out_unregister;
	}
	return 0;

out_unregister:
	spin_lock_bh(&zcrypt_device_lock);
	zcrypt_device_count--;
	list_del_init(&zdev->list);
	spin_unlock_bh(&zcrypt_device_lock);
	sysfs_remove_group(&zdev->ap_dev->device.kobj,
			   &zcrypt_device_attr_group);
	put_device(&zdev->ap_dev->device);
	zcrypt_device_put(zdev);
out:
	return rc;
}
EXPORT_SYMBOL(zcrypt_device_register);

/**
 * zcrypt_device_unregister(): Unregister a crypto device.
 * @zdev: Pointer to crypto device
 *
 * Unregister a crypto device.
 */
void zcrypt_device_unregister(struct zcrypt_device *zdev)
{
	if (zdev->ops->rng)
		zcrypt_rng_device_remove();
	spin_lock_bh(&zcrypt_device_lock);
	zcrypt_device_count--;
	list_del_init(&zdev->list);
	spin_unlock_bh(&zcrypt_device_lock);
	sysfs_remove_group(&zdev->ap_dev->device.kobj,
			   &zcrypt_device_attr_group);
	put_device(&zdev->ap_dev->device);
	zcrypt_device_put(zdev);
}
EXPORT_SYMBOL(zcrypt_device_unregister);

void zcrypt_msgtype_register(struct zcrypt_ops *zops)
{
	spin_lock_bh(&zcrypt_ops_list_lock);
	list_add_tail(&zops->list, &zcrypt_ops_list);
	spin_unlock_bh(&zcrypt_ops_list_lock);
}
EXPORT_SYMBOL(zcrypt_msgtype_register);

void zcrypt_msgtype_unregister(struct zcrypt_ops *zops)
{
	spin_lock_bh(&zcrypt_ops_list_lock);
	list_del_init(&zops->list);
	spin_unlock_bh(&zcrypt_ops_list_lock);
}
EXPORT_SYMBOL(zcrypt_msgtype_unregister);

static inline
struct zcrypt_ops *__ops_lookup(unsigned char *name, int variant)
{
	struct zcrypt_ops *zops;
	int found = 0;

	spin_lock_bh(&zcrypt_ops_list_lock);
	list_for_each_entry(zops, &zcrypt_ops_list, list) {
		if ((zops->variant == variant) &&
		    (!strncmp(zops->name, name, sizeof(zops->name)))) {
			found = 1;
			break;
		}
	}
	if (!found || !try_module_get(zops->owner))
		zops = NULL;

	spin_unlock_bh(&zcrypt_ops_list_lock);

	return zops;
}

struct zcrypt_ops *zcrypt_msgtype_request(unsigned char *name, int variant)
{
	struct zcrypt_ops *zops = NULL;

	zops = __ops_lookup(name, variant);
	if (!zops) {
		request_module("%s", name);
		zops = __ops_lookup(name, variant);
	}
	return zops;
}
EXPORT_SYMBOL(zcrypt_msgtype_request);

void zcrypt_msgtype_release(struct zcrypt_ops *zops)
{
	if (zops)
		module_put(zops->owner);
}
EXPORT_SYMBOL(zcrypt_msgtype_release);

/**
 * zcrypt_read (): Not supported beyond zcrypt 1.3.1.
 *
 * This function is not supported beyond zcrypt 1.3.1.
 */
static ssize_t zcrypt_read(struct file *filp, char __user *buf,
			   size_t count, loff_t *f_pos)
{
	return -EPERM;
}

/**
 * zcrypt_write(): Not allowed.
 *
 * Write is is not allowed
 */
static ssize_t zcrypt_write(struct file *filp, const char __user *buf,
			    size_t count, loff_t *f_pos)
{
	return -EPERM;
}

/**
 * zcrypt_open(): Count number of users.
 *
 * Device open function to count number of users.
 */
static int zcrypt_open(struct inode *inode, struct file *filp)
{
	atomic_inc(&zcrypt_open_count);
	return nonseekable_open(inode, filp);
}

/**
 * zcrypt_release(): Count number of users.
 *
 * Device close function to count number of users.
 */
static int zcrypt_release(struct inode *inode, struct file *filp)
{
	atomic_dec(&zcrypt_open_count);
	return 0;
}

/*
 * zcrypt ioctls.
 */
static long zcrypt_rsa_modexpo(struct ica_rsa_modexpo *mex)
{
	struct zcrypt_device *zdev;
	int rc;

	if (mex->outputdatalength < mex->inputdatalength)
		return -EINVAL;
	/*
	 * As long as outputdatalength is big enough, we can set the
	 * outputdatalength equal to the inputdatalength, since that is the
	 * number of bytes we will copy in any case
	 */
	mex->outputdatalength = mex->inputdatalength;

	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list) {
		if (!zdev->online ||
		    !zdev->ops->rsa_modexpo ||
		    zdev->min_mod_size > mex->inputdatalength ||
		    zdev->max_mod_size < mex->inputdatalength)
			continue;
		zcrypt_device_get(zdev);
		get_device(&zdev->ap_dev->device);
		zdev->request_count++;
		__zcrypt_decrease_preference(zdev);
		if (try_module_get(zdev->ap_dev->drv->driver.owner)) {
			spin_unlock_bh(&zcrypt_device_lock);
			rc = zdev->ops->rsa_modexpo(zdev, mex);
			spin_lock_bh(&zcrypt_device_lock);
			module_put(zdev->ap_dev->drv->driver.owner);
		}
		else
			rc = -EAGAIN;
		zdev->request_count--;
		__zcrypt_increase_preference(zdev);
		put_device(&zdev->ap_dev->device);
		zcrypt_device_put(zdev);
		spin_unlock_bh(&zcrypt_device_lock);
		return rc;
	}
	spin_unlock_bh(&zcrypt_device_lock);
	return -ENODEV;
}

static long zcrypt_rsa_crt(struct ica_rsa_modexpo_crt *crt)
{
	struct zcrypt_device *zdev;
	unsigned long long z1, z2, z3;
	int rc, copied;

	if (crt->outputdatalength < crt->inputdatalength)
		return -EINVAL;
	/*
	 * As long as outputdatalength is big enough, we can set the
	 * outputdatalength equal to the inputdatalength, since that is the
	 * number of bytes we will copy in any case
	 */
	crt->outputdatalength = crt->inputdatalength;

	copied = 0;
 restart:
	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list) {
		if (!zdev->online ||
		    !zdev->ops->rsa_modexpo_crt ||
		    zdev->min_mod_size > crt->inputdatalength ||
		    zdev->max_mod_size < crt->inputdatalength)
			continue;
		if (zdev->short_crt && crt->inputdatalength > 240) {
			/*
			 * Check inputdata for leading zeros for cards
			 * that can't handle np_prime, bp_key, or
			 * u_mult_inv > 128 bytes.
			 */
			if (copied == 0) {
				unsigned int len;
				spin_unlock_bh(&zcrypt_device_lock);
				/* len is max 256 / 2 - 120 = 8
				 * For bigger device just assume len of leading
				 * 0s is 8 as stated in the requirements for
				 * ica_rsa_modexpo_crt struct in zcrypt.h.
				 */
				if (crt->inputdatalength <= 256)
					len = crt->inputdatalength / 2 - 120;
				else
					len = 8;
				if (len > sizeof(z1))
					return -EFAULT;
				z1 = z2 = z3 = 0;
				if (copy_from_user(&z1, crt->np_prime, len) ||
				    copy_from_user(&z2, crt->bp_key, len) ||
				    copy_from_user(&z3, crt->u_mult_inv, len))
					return -EFAULT;
				z1 = z2 = z3 = 0;
				copied = 1;
				/*
				 * We have to restart device lookup -
				 * the device list may have changed by now.
				 */
				goto restart;
			}
			if (z1 != 0ULL || z2 != 0ULL || z3 != 0ULL)
				/* The device can't handle this request. */
				continue;
		}
		zcrypt_device_get(zdev);
		get_device(&zdev->ap_dev->device);
		zdev->request_count++;
		__zcrypt_decrease_preference(zdev);
		if (try_module_get(zdev->ap_dev->drv->driver.owner)) {
			spin_unlock_bh(&zcrypt_device_lock);
			rc = zdev->ops->rsa_modexpo_crt(zdev, crt);
			spin_lock_bh(&zcrypt_device_lock);
			module_put(zdev->ap_dev->drv->driver.owner);
		}
		else
			rc = -EAGAIN;
		zdev->request_count--;
		__zcrypt_increase_preference(zdev);
		put_device(&zdev->ap_dev->device);
		zcrypt_device_put(zdev);
		spin_unlock_bh(&zcrypt_device_lock);
		return rc;
	}
	spin_unlock_bh(&zcrypt_device_lock);
	return -ENODEV;
}

static long zcrypt_send_cprb(struct ica_xcRB *xcRB)
{
	struct zcrypt_device *zdev;
	int rc;

	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list) {
		if (!zdev->online || !zdev->ops->send_cprb ||
		   (zdev->ops->variant == MSGTYPE06_VARIANT_EP11) ||
		   (xcRB->user_defined != AUTOSELECT &&
		    AP_QID_DEVICE(zdev->ap_dev->qid) != xcRB->user_defined))
			continue;
		zcrypt_device_get(zdev);
		get_device(&zdev->ap_dev->device);
		zdev->request_count++;
		__zcrypt_decrease_preference(zdev);
		if (try_module_get(zdev->ap_dev->drv->driver.owner)) {
			spin_unlock_bh(&zcrypt_device_lock);
			rc = zdev->ops->send_cprb(zdev, xcRB);
			spin_lock_bh(&zcrypt_device_lock);
			module_put(zdev->ap_dev->drv->driver.owner);
		}
		else
			rc = -EAGAIN;
		zdev->request_count--;
		__zcrypt_increase_preference(zdev);
		put_device(&zdev->ap_dev->device);
		zcrypt_device_put(zdev);
		spin_unlock_bh(&zcrypt_device_lock);
		return rc;
	}
	spin_unlock_bh(&zcrypt_device_lock);
	return -ENODEV;
}

struct ep11_target_dev_list {
	unsigned short		targets_num;
	struct ep11_target_dev	*targets;
};

static bool is_desired_ep11dev(unsigned int dev_qid,
			       struct ep11_target_dev_list dev_list)
{
	int n;

	for (n = 0; n < dev_list.targets_num; n++, dev_list.targets++) {
		if ((AP_QID_DEVICE(dev_qid) == dev_list.targets->ap_id) &&
		    (AP_QID_QUEUE(dev_qid) == dev_list.targets->dom_id)) {
			return true;
		}
	}
	return false;
}

static long zcrypt_send_ep11_cprb(struct ep11_urb *xcrb)
{
	struct zcrypt_device *zdev;
	bool autoselect = false;
	int rc;
	struct ep11_target_dev_list ep11_dev_list = {
		.targets_num	=  0x00,
		.targets	=  NULL,
	};

	ep11_dev_list.targets_num = (unsigned short) xcrb->targets_num;

	/* empty list indicates autoselect (all available targets) */
	if (ep11_dev_list.targets_num == 0)
		autoselect = true;
	else {
		ep11_dev_list.targets = kcalloc((unsigned short)
						xcrb->targets_num,
						sizeof(struct ep11_target_dev),
						GFP_KERNEL);
		if (!ep11_dev_list.targets)
			return -ENOMEM;

		if (copy_from_user(ep11_dev_list.targets,
				   (struct ep11_target_dev __force __user *)
				   xcrb->targets, xcrb->targets_num *
				   sizeof(struct ep11_target_dev)))
			return -EFAULT;
	}

	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list) {
		/* check if device is eligible */
		if (!zdev->online ||
		    zdev->ops->variant != MSGTYPE06_VARIANT_EP11)
			continue;

		/* check if device is selected as valid target */
		if (!is_desired_ep11dev(zdev->ap_dev->qid, ep11_dev_list) &&
		    !autoselect)
			continue;

		zcrypt_device_get(zdev);
		get_device(&zdev->ap_dev->device);
		zdev->request_count++;
		__zcrypt_decrease_preference(zdev);
		if (try_module_get(zdev->ap_dev->drv->driver.owner)) {
			spin_unlock_bh(&zcrypt_device_lock);
			rc = zdev->ops->send_ep11_cprb(zdev, xcrb);
			spin_lock_bh(&zcrypt_device_lock);
			module_put(zdev->ap_dev->drv->driver.owner);
		} else {
			rc = -EAGAIN;
		  }
		zdev->request_count--;
		__zcrypt_increase_preference(zdev);
		put_device(&zdev->ap_dev->device);
		zcrypt_device_put(zdev);
		spin_unlock_bh(&zcrypt_device_lock);
		return rc;
	}
	spin_unlock_bh(&zcrypt_device_lock);
	return -ENODEV;
}

static long zcrypt_rng(char *buffer)
{
	struct zcrypt_device *zdev;
	int rc;

	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list) {
		if (!zdev->online || !zdev->ops->rng)
			continue;
		zcrypt_device_get(zdev);
		get_device(&zdev->ap_dev->device);
		zdev->request_count++;
		__zcrypt_decrease_preference(zdev);
		if (try_module_get(zdev->ap_dev->drv->driver.owner)) {
			spin_unlock_bh(&zcrypt_device_lock);
			rc = zdev->ops->rng(zdev, buffer);
			spin_lock_bh(&zcrypt_device_lock);
			module_put(zdev->ap_dev->drv->driver.owner);
		} else
			rc = -EAGAIN;
		zdev->request_count--;
		__zcrypt_increase_preference(zdev);
		put_device(&zdev->ap_dev->device);
		zcrypt_device_put(zdev);
		spin_unlock_bh(&zcrypt_device_lock);
		return rc;
	}
	spin_unlock_bh(&zcrypt_device_lock);
	return -ENODEV;
}

static void zcrypt_status_mask(char status[AP_DEVICES])
{
	struct zcrypt_device *zdev;

	memset(status, 0, sizeof(char) * AP_DEVICES);
	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list)
		status[AP_QID_DEVICE(zdev->ap_dev->qid)] =
			zdev->online ? zdev->user_space_type : 0x0d;
	spin_unlock_bh(&zcrypt_device_lock);
}

static void zcrypt_qdepth_mask(char qdepth[AP_DEVICES])
{
	struct zcrypt_device *zdev;

	memset(qdepth, 0, sizeof(char)	* AP_DEVICES);
	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list) {
		spin_lock(&zdev->ap_dev->lock);
		qdepth[AP_QID_DEVICE(zdev->ap_dev->qid)] =
			zdev->ap_dev->pendingq_count +
			zdev->ap_dev->requestq_count;
		spin_unlock(&zdev->ap_dev->lock);
	}
	spin_unlock_bh(&zcrypt_device_lock);
}

static void zcrypt_perdev_reqcnt(int reqcnt[AP_DEVICES])
{
	struct zcrypt_device *zdev;

	memset(reqcnt, 0, sizeof(int) * AP_DEVICES);
	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list) {
		spin_lock(&zdev->ap_dev->lock);
		reqcnt[AP_QID_DEVICE(zdev->ap_dev->qid)] =
			zdev->ap_dev->total_request_count;
		spin_unlock(&zdev->ap_dev->lock);
	}
	spin_unlock_bh(&zcrypt_device_lock);
}

static int zcrypt_pendingq_count(void)
{
	struct zcrypt_device *zdev;
	int pendingq_count = 0;

	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list) {
		spin_lock(&zdev->ap_dev->lock);
		pendingq_count += zdev->ap_dev->pendingq_count;
		spin_unlock(&zdev->ap_dev->lock);
	}
	spin_unlock_bh(&zcrypt_device_lock);
	return pendingq_count;
}

static int zcrypt_requestq_count(void)
{
	struct zcrypt_device *zdev;
	int requestq_count = 0;

	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list) {
		spin_lock(&zdev->ap_dev->lock);
		requestq_count += zdev->ap_dev->requestq_count;
		spin_unlock(&zdev->ap_dev->lock);
	}
	spin_unlock_bh(&zcrypt_device_lock);
	return requestq_count;
}

static int zcrypt_count_type(int type)
{
	struct zcrypt_device *zdev;
	int device_count = 0;

	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list)
		if (zdev->user_space_type == type)
			device_count++;
	spin_unlock_bh(&zcrypt_device_lock);
	return device_count;
}

/**
 * zcrypt_ica_status(): Old, depracted combi status call.
 *
 * Old, deprecated combi status call.
 */
static long zcrypt_ica_status(struct file *filp, unsigned long arg)
{
	struct ica_z90_status *pstat;
	int ret;

	pstat = kzalloc(sizeof(*pstat), GFP_KERNEL);
	if (!pstat)
		return -ENOMEM;
	pstat->totalcount = zcrypt_device_count;
	pstat->leedslitecount = zcrypt_count_type(ZCRYPT_PCICA);
	pstat->leeds2count = zcrypt_count_type(ZCRYPT_PCICC);
	pstat->requestqWaitCount = zcrypt_requestq_count();
	pstat->pendingqWaitCount = zcrypt_pendingq_count();
	pstat->totalOpenCount = atomic_read(&zcrypt_open_count);
	pstat->cryptoDomain = ap_domain_index;
	zcrypt_status_mask(pstat->status);
	zcrypt_qdepth_mask(pstat->qdepth);
	ret = 0;
	if (copy_to_user((void __user *) arg, pstat, sizeof(*pstat)))
		ret = -EFAULT;
	kfree(pstat);
	return ret;
}

static long zcrypt_unlocked_ioctl(struct file *filp, unsigned int cmd,
				  unsigned long arg)
{
	int rc;

	switch (cmd) {
	case ICARSAMODEXPO: {
		struct ica_rsa_modexpo __user *umex = (void __user *) arg;
		struct ica_rsa_modexpo mex;
		if (copy_from_user(&mex, umex, sizeof(mex)))
			return -EFAULT;
		do {
			rc = zcrypt_rsa_modexpo(&mex);
		} while (rc == -EAGAIN);
		/* on failure: retry once again after a requested rescan */
		if ((rc == -ENODEV) && (zcrypt_process_rescan()))
			do {
				rc = zcrypt_rsa_modexpo(&mex);
			} while (rc == -EAGAIN);
		if (rc)
			return rc;
		return put_user(mex.outputdatalength, &umex->outputdatalength);
	}
	case ICARSACRT: {
		struct ica_rsa_modexpo_crt __user *ucrt = (void __user *) arg;
		struct ica_rsa_modexpo_crt crt;
		if (copy_from_user(&crt, ucrt, sizeof(crt)))
			return -EFAULT;
		do {
			rc = zcrypt_rsa_crt(&crt);
		} while (rc == -EAGAIN);
		/* on failure: retry once again after a requested rescan */
		if ((rc == -ENODEV) && (zcrypt_process_rescan()))
			do {
				rc = zcrypt_rsa_crt(&crt);
			} while (rc == -EAGAIN);
		if (rc)
			return rc;
		return put_user(crt.outputdatalength, &ucrt->outputdatalength);
	}
	case ZSECSENDCPRB: {
		struct ica_xcRB __user *uxcRB = (void __user *) arg;
		struct ica_xcRB xcRB;
		if (copy_from_user(&xcRB, uxcRB, sizeof(xcRB)))
			return -EFAULT;
		do {
			rc = zcrypt_send_cprb(&xcRB);
		} while (rc == -EAGAIN);
		/* on failure: retry once again after a requested rescan */
		if ((rc == -ENODEV) && (zcrypt_process_rescan()))
			do {
				rc = zcrypt_send_cprb(&xcRB);
			} while (rc == -EAGAIN);
		if (copy_to_user(uxcRB, &xcRB, sizeof(xcRB)))
			return -EFAULT;
		return rc;
	}
	case ZSENDEP11CPRB: {
		struct ep11_urb __user *uxcrb = (void __user *)arg;
		struct ep11_urb xcrb;
		if (copy_from_user(&xcrb, uxcrb, sizeof(xcrb)))
			return -EFAULT;
		do {
			rc = zcrypt_send_ep11_cprb(&xcrb);
		} while (rc == -EAGAIN);
		/* on failure: retry once again after a requested rescan */
		if ((rc == -ENODEV) && (zcrypt_process_rescan()))
			do {
				rc = zcrypt_send_ep11_cprb(&xcrb);
			} while (rc == -EAGAIN);
		if (copy_to_user(uxcrb, &xcrb, sizeof(xcrb)))
			return -EFAULT;
		return rc;
	}
	case Z90STAT_STATUS_MASK: {
		char status[AP_DEVICES];
		zcrypt_status_mask(status);
		if (copy_to_user((char __user *) arg, status,
				 sizeof(char) * AP_DEVICES))
			return -EFAULT;
		return 0;
	}
	case Z90STAT_QDEPTH_MASK: {
		char qdepth[AP_DEVICES];
		zcrypt_qdepth_mask(qdepth);
		if (copy_to_user((char __user *) arg, qdepth,
				 sizeof(char) * AP_DEVICES))
			return -EFAULT;
		return 0;
	}
	case Z90STAT_PERDEV_REQCNT: {
		int reqcnt[AP_DEVICES];
		zcrypt_perdev_reqcnt(reqcnt);
		if (copy_to_user((int __user *) arg, reqcnt,
				 sizeof(int) * AP_DEVICES))
			return -EFAULT;
		return 0;
	}
	case Z90STAT_REQUESTQ_COUNT:
		return put_user(zcrypt_requestq_count(), (int __user *) arg);
	case Z90STAT_PENDINGQ_COUNT:
		return put_user(zcrypt_pendingq_count(), (int __user *) arg);
	case Z90STAT_TOTALOPEN_COUNT:
		return put_user(atomic_read(&zcrypt_open_count),
				(int __user *) arg);
	case Z90STAT_DOMAIN_INDEX:
		return put_user(ap_domain_index, (int __user *) arg);
	/*
	 * Deprecated ioctls. Don't add another device count ioctl,
	 * you can count them yourself in the user space with the
	 * output of the Z90STAT_STATUS_MASK ioctl.
	 */
	case ICAZ90STATUS:
		return zcrypt_ica_status(filp, arg);
	case Z90STAT_TOTALCOUNT:
		return put_user(zcrypt_device_count, (int __user *) arg);
	case Z90STAT_PCICACOUNT:
		return put_user(zcrypt_count_type(ZCRYPT_PCICA),
				(int __user *) arg);
	case Z90STAT_PCICCCOUNT:
		return put_user(zcrypt_count_type(ZCRYPT_PCICC),
				(int __user *) arg);
	case Z90STAT_PCIXCCMCL2COUNT:
		return put_user(zcrypt_count_type(ZCRYPT_PCIXCC_MCL2),
				(int __user *) arg);
	case Z90STAT_PCIXCCMCL3COUNT:
		return put_user(zcrypt_count_type(ZCRYPT_PCIXCC_MCL3),
				(int __user *) arg);
	case Z90STAT_PCIXCCCOUNT:
		return put_user(zcrypt_count_type(ZCRYPT_PCIXCC_MCL2) +
				zcrypt_count_type(ZCRYPT_PCIXCC_MCL3),
				(int __user *) arg);
	case Z90STAT_CEX2CCOUNT:
		return put_user(zcrypt_count_type(ZCRYPT_CEX2C),
				(int __user *) arg);
	case Z90STAT_CEX2ACOUNT:
		return put_user(zcrypt_count_type(ZCRYPT_CEX2A),
				(int __user *) arg);
	default:
		/* unknown ioctl number */
		return -ENOIOCTLCMD;
	}
}

#ifdef CONFIG_COMPAT
/*
 * ioctl32 conversion routines
 */
struct compat_ica_rsa_modexpo {
	compat_uptr_t	inputdata;
	unsigned int	inputdatalength;
	compat_uptr_t	outputdata;
	unsigned int	outputdatalength;
	compat_uptr_t	b_key;
	compat_uptr_t	n_modulus;
};

static long trans_modexpo32(struct file *filp, unsigned int cmd,
			    unsigned long arg)
{
	struct compat_ica_rsa_modexpo __user *umex32 = compat_ptr(arg);
	struct compat_ica_rsa_modexpo mex32;
	struct ica_rsa_modexpo mex64;
	long rc;

	if (copy_from_user(&mex32, umex32, sizeof(mex32)))
		return -EFAULT;
	mex64.inputdata = compat_ptr(mex32.inputdata);
	mex64.inputdatalength = mex32.inputdatalength;
	mex64.outputdata = compat_ptr(mex32.outputdata);
	mex64.outputdatalength = mex32.outputdatalength;
	mex64.b_key = compat_ptr(mex32.b_key);
	mex64.n_modulus = compat_ptr(mex32.n_modulus);
	do {
		rc = zcrypt_rsa_modexpo(&mex64);
	} while (rc == -EAGAIN);
	/* on failure: retry once again after a requested rescan */
	if ((rc == -ENODEV) && (zcrypt_process_rescan()))
		do {
			rc = zcrypt_rsa_modexpo(&mex64);
		} while (rc == -EAGAIN);
	if (rc)
		return rc;
	return put_user(mex64.outputdatalength,
			&umex32->outputdatalength);
}

struct compat_ica_rsa_modexpo_crt {
	compat_uptr_t	inputdata;
	unsigned int	inputdatalength;
	compat_uptr_t	outputdata;
	unsigned int	outputdatalength;
	compat_uptr_t	bp_key;
	compat_uptr_t	bq_key;
	compat_uptr_t	np_prime;
	compat_uptr_t	nq_prime;
	compat_uptr_t	u_mult_inv;
};

static long trans_modexpo_crt32(struct file *filp, unsigned int cmd,
				unsigned long arg)
{
	struct compat_ica_rsa_modexpo_crt __user *ucrt32 = compat_ptr(arg);
	struct compat_ica_rsa_modexpo_crt crt32;
	struct ica_rsa_modexpo_crt crt64;
	long rc;

	if (copy_from_user(&crt32, ucrt32, sizeof(crt32)))
		return -EFAULT;
	crt64.inputdata = compat_ptr(crt32.inputdata);
	crt64.inputdatalength = crt32.inputdatalength;
	crt64.outputdata=  compat_ptr(crt32.outputdata);
	crt64.outputdatalength = crt32.outputdatalength;
	crt64.bp_key = compat_ptr(crt32.bp_key);
	crt64.bq_key = compat_ptr(crt32.bq_key);
	crt64.np_prime = compat_ptr(crt32.np_prime);
	crt64.nq_prime = compat_ptr(crt32.nq_prime);
	crt64.u_mult_inv = compat_ptr(crt32.u_mult_inv);
	do {
		rc = zcrypt_rsa_crt(&crt64);
	} while (rc == -EAGAIN);
	/* on failure: retry once again after a requested rescan */
	if ((rc == -ENODEV) && (zcrypt_process_rescan()))
		do {
			rc = zcrypt_rsa_crt(&crt64);
		} while (rc == -EAGAIN);
	if (rc)
		return rc;
	return put_user(crt64.outputdatalength,
			&ucrt32->outputdatalength);
}

struct compat_ica_xcRB {
	unsigned short	agent_ID;
	unsigned int	user_defined;
	unsigned short	request_ID;
	unsigned int	request_control_blk_length;
	unsigned char	padding1[16 - sizeof (compat_uptr_t)];
	compat_uptr_t	request_control_blk_addr;
	unsigned int	request_data_length;
	char		padding2[16 - sizeof (compat_uptr_t)];
	compat_uptr_t	request_data_address;
	unsigned int	reply_control_blk_length;
	char		padding3[16 - sizeof (compat_uptr_t)];
	compat_uptr_t	reply_control_blk_addr;
	unsigned int	reply_data_length;
	char		padding4[16 - sizeof (compat_uptr_t)];
	compat_uptr_t	reply_data_addr;
	unsigned short	priority_window;
	unsigned int	status;
} __attribute__((packed));

static long trans_xcRB32(struct file *filp, unsigned int cmd,
			 unsigned long arg)
{
	struct compat_ica_xcRB __user *uxcRB32 = compat_ptr(arg);
	struct compat_ica_xcRB xcRB32;
	struct ica_xcRB xcRB64;
	long rc;

	if (copy_from_user(&xcRB32, uxcRB32, sizeof(xcRB32)))
		return -EFAULT;
	xcRB64.agent_ID = xcRB32.agent_ID;
	xcRB64.user_defined = xcRB32.user_defined;
	xcRB64.request_ID = xcRB32.request_ID;
	xcRB64.request_control_blk_length =
		xcRB32.request_control_blk_length;
	xcRB64.request_control_blk_addr =
		compat_ptr(xcRB32.request_control_blk_addr);
	xcRB64.request_data_length =
		xcRB32.request_data_length;
	xcRB64.request_data_address =
		compat_ptr(xcRB32.request_data_address);
	xcRB64.reply_control_blk_length =
		xcRB32.reply_control_blk_length;
	xcRB64.reply_control_blk_addr =
		compat_ptr(xcRB32.reply_control_blk_addr);
	xcRB64.reply_data_length = xcRB32.reply_data_length;
	xcRB64.reply_data_addr =
		compat_ptr(xcRB32.reply_data_addr);
	xcRB64.priority_window = xcRB32.priority_window;
	xcRB64.status = xcRB32.status;
	do {
		rc = zcrypt_send_cprb(&xcRB64);
	} while (rc == -EAGAIN);
	/* on failure: retry once again after a requested rescan */
	if ((rc == -ENODEV) && (zcrypt_process_rescan()))
		do {
			rc = zcrypt_send_cprb(&xcRB64);
		} while (rc == -EAGAIN);
	xcRB32.reply_control_blk_length = xcRB64.reply_control_blk_length;
	xcRB32.reply_data_length = xcRB64.reply_data_length;
	xcRB32.status = xcRB64.status;
	if (copy_to_user(uxcRB32, &xcRB32, sizeof(xcRB32)))
			return -EFAULT;
	return rc;
}

static long zcrypt_compat_ioctl(struct file *filp, unsigned int cmd,
			 unsigned long arg)
{
	if (cmd == ICARSAMODEXPO)
		return trans_modexpo32(filp, cmd, arg);
	if (cmd == ICARSACRT)
		return trans_modexpo_crt32(filp, cmd, arg);
	if (cmd == ZSECSENDCPRB)
		return trans_xcRB32(filp, cmd, arg);
	return zcrypt_unlocked_ioctl(filp, cmd, arg);
}
#endif

/*
 * Misc device file operations.
 */
static const struct file_operations zcrypt_fops = {
	.owner		= THIS_MODULE,
	.read		= zcrypt_read,
	.write		= zcrypt_write,
	.unlocked_ioctl	= zcrypt_unlocked_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl	= zcrypt_compat_ioctl,
#endif
	.open		= zcrypt_open,
	.release	= zcrypt_release,
	.llseek		= no_llseek,
};

/*
 * Misc device.
 */
static struct miscdevice zcrypt_misc_device = {
	.minor	    = MISC_DYNAMIC_MINOR,
	.name	    = "z90crypt",
	.fops	    = &zcrypt_fops,
};

/*
 * Deprecated /proc entry support.
 */
static struct proc_dir_entry *zcrypt_entry;

static void sprintcl(struct seq_file *m, unsigned char *addr, unsigned int len)
{
	int i;

	for (i = 0; i < len; i++)
		seq_printf(m, "%01x", (unsigned int) addr[i]);
	seq_putc(m, ' ');
}

static void sprintrw(struct seq_file *m, unsigned char *addr, unsigned int len)
{
	int inl, c, cx;

	seq_printf(m, "	   ");
	inl = 0;
	for (c = 0; c < (len / 16); c++) {
		sprintcl(m, addr+inl, 16);
		inl += 16;
	}
	cx = len%16;
	if (cx) {
		sprintcl(m, addr+inl, cx);
		inl += cx;
	}
	seq_putc(m, '\n');
}

static void sprinthx(unsigned char *title, struct seq_file *m,
		     unsigned char *addr, unsigned int len)
{
	int inl, r, rx;

	seq_printf(m, "\n%s\n", title);
	inl = 0;
	for (r = 0; r < (len / 64); r++) {
		sprintrw(m, addr+inl, 64);
		inl += 64;
	}
	rx = len % 64;
	if (rx) {
		sprintrw(m, addr+inl, rx);
		inl += rx;
	}
	seq_putc(m, '\n');
}

static void sprinthx4(unsigned char *title, struct seq_file *m,
		      unsigned int *array, unsigned int len)
{
	seq_printf(m, "\n%s\n", title);
	seq_hex_dump(m, "    ", DUMP_PREFIX_NONE, 32, 4, array, len, false);
	seq_putc(m, '\n');
}

static int zcrypt_proc_show(struct seq_file *m, void *v)
{
	char workarea[sizeof(int) * AP_DEVICES];

	seq_printf(m, "\nzcrypt version: %d.%d.%d\n",
		   ZCRYPT_VERSION, ZCRYPT_RELEASE, ZCRYPT_VARIANT);
	seq_printf(m, "Cryptographic domain: %d\n", ap_domain_index);
	seq_printf(m, "Total device count: %d\n", zcrypt_device_count);
	seq_printf(m, "PCICA count: %d\n", zcrypt_count_type(ZCRYPT_PCICA));
	seq_printf(m, "PCICC count: %d\n", zcrypt_count_type(ZCRYPT_PCICC));
	seq_printf(m, "PCIXCC MCL2 count: %d\n",
		   zcrypt_count_type(ZCRYPT_PCIXCC_MCL2));
	seq_printf(m, "PCIXCC MCL3 count: %d\n",
		   zcrypt_count_type(ZCRYPT_PCIXCC_MCL3));
	seq_printf(m, "CEX2C count: %d\n", zcrypt_count_type(ZCRYPT_CEX2C));
	seq_printf(m, "CEX2A count: %d\n", zcrypt_count_type(ZCRYPT_CEX2A));
	seq_printf(m, "CEX3C count: %d\n", zcrypt_count_type(ZCRYPT_CEX3C));
	seq_printf(m, "CEX3A count: %d\n", zcrypt_count_type(ZCRYPT_CEX3A));
	seq_printf(m, "requestq count: %d\n", zcrypt_requestq_count());
	seq_printf(m, "pendingq count: %d\n", zcrypt_pendingq_count());
	seq_printf(m, "Total open handles: %d\n\n",
		   atomic_read(&zcrypt_open_count));
	zcrypt_status_mask(workarea);
	sprinthx("Online devices: 1=PCICA 2=PCICC 3=PCIXCC(MCL2) "
		 "4=PCIXCC(MCL3) 5=CEX2C 6=CEX2A 7=CEX3C 8=CEX3A",
		 m, workarea, AP_DEVICES);
	zcrypt_qdepth_mask(workarea);
	sprinthx("Waiting work element counts", m, workarea, AP_DEVICES);
	zcrypt_perdev_reqcnt((int *) workarea);
	sprinthx4("Per-device successfully completed request counts",
		  m, (unsigned int *) workarea, AP_DEVICES);
	return 0;
}

static int zcrypt_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, zcrypt_proc_show, NULL);
}

static void zcrypt_disable_card(int index)
{
	struct zcrypt_device *zdev;

	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list)
		if (AP_QID_DEVICE(zdev->ap_dev->qid) == index) {
			zdev->online = 0;
			ap_flush_queue(zdev->ap_dev);
			break;
		}
	spin_unlock_bh(&zcrypt_device_lock);
}

static void zcrypt_enable_card(int index)
{
	struct zcrypt_device *zdev;

	spin_lock_bh(&zcrypt_device_lock);
	list_for_each_entry(zdev, &zcrypt_device_list, list)
		if (AP_QID_DEVICE(zdev->ap_dev->qid) == index) {
			zdev->online = 1;
			break;
		}
	spin_unlock_bh(&zcrypt_device_lock);
}

static ssize_t zcrypt_proc_write(struct file *file, const char __user *buffer,
				 size_t count, loff_t *pos)
{
	unsigned char *lbuf, *ptr;
	size_t local_count;
	int j;

	if (count <= 0)
		return 0;

#define LBUFSIZE 1200UL
	lbuf = kmalloc(LBUFSIZE, GFP_KERNEL);
	if (!lbuf)
		return 0;

	local_count = min(LBUFSIZE - 1, count);
	if (copy_from_user(lbuf, buffer, local_count) != 0) {
		kfree(lbuf);
		return -EFAULT;
	}
	lbuf[local_count] = '\0';

	ptr = strstr(lbuf, "Online devices");
	if (!ptr)
		goto out;
	ptr = strstr(ptr, "\n");
	if (!ptr)
		goto out;
	ptr++;

	if (strstr(ptr, "Waiting work element counts") == NULL)
		goto out;

	for (j = 0; j < 64 && *ptr; ptr++) {
		/*
		 * '0' for no device, '1' for PCICA, '2' for PCICC,
		 * '3' for PCIXCC_MCL2, '4' for PCIXCC_MCL3,
		 * '5' for CEX2C and '6' for CEX2A'
		 * '7' for CEX3C and '8' for CEX3A
		 */
		if (*ptr >= '0' && *ptr <= '8')
			j++;
		else if (*ptr == 'd' || *ptr == 'D')
			zcrypt_disable_card(j++);
		else if (*ptr == 'e' || *ptr == 'E')
			zcrypt_enable_card(j++);
		else if (*ptr != ' ' && *ptr != '\t')
			break;
	}
out:
	kfree(lbuf);
	return count;
}

static const struct file_operations zcrypt_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= zcrypt_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= zcrypt_proc_write,
};

static int zcrypt_rng_device_count;
static u32 *zcrypt_rng_buffer;
static int zcrypt_rng_buffer_index;
static DEFINE_MUTEX(zcrypt_rng_mutex);

static int zcrypt_rng_data_read(struct hwrng *rng, u32 *data)
{
	int rc;

	/*
	 * We don't need locking here because the RNG API guarantees serialized
	 * read method calls.
	 */
	if (zcrypt_rng_buffer_index == 0) {
		rc = zcrypt_rng((char *) zcrypt_rng_buffer);
		/* on failure: retry once again after a requested rescan */
		if ((rc == -ENODEV) && (zcrypt_process_rescan()))
			rc = zcrypt_rng((char *) zcrypt_rng_buffer);
		if (rc < 0)
			return -EIO;
		zcrypt_rng_buffer_index = rc / sizeof *data;
	}
	*data = zcrypt_rng_buffer[--zcrypt_rng_buffer_index];
	return sizeof *data;
}

static struct hwrng zcrypt_rng_dev = {
	.name		= "zcrypt",
	.data_read	= zcrypt_rng_data_read,
	.quality	= 990,
};

static int zcrypt_rng_device_add(void)
{
	int rc = 0;

	mutex_lock(&zcrypt_rng_mutex);
	if (zcrypt_rng_device_count == 0) {
		zcrypt_rng_buffer = (u32 *) get_zeroed_page(GFP_KERNEL);
		if (!zcrypt_rng_buffer) {
			rc = -ENOMEM;
			goto out;
		}
		zcrypt_rng_buffer_index = 0;
		if (!zcrypt_hwrng_seed)
			zcrypt_rng_dev.quality = 0;
		rc = hwrng_register(&zcrypt_rng_dev);
		if (rc)
			goto out_free;
		zcrypt_rng_device_count = 1;
	} else
		zcrypt_rng_device_count++;
	mutex_unlock(&zcrypt_rng_mutex);
	return 0;

out_free:
	free_page((unsigned long) zcrypt_rng_buffer);
out:
	mutex_unlock(&zcrypt_rng_mutex);
	return rc;
}

static void zcrypt_rng_device_remove(void)
{
	mutex_lock(&zcrypt_rng_mutex);
	zcrypt_rng_device_count--;
	if (zcrypt_rng_device_count == 0) {
		hwrng_unregister(&zcrypt_rng_dev);
		free_page((unsigned long) zcrypt_rng_buffer);
	}
	mutex_unlock(&zcrypt_rng_mutex);
}

int __init zcrypt_debug_init(void)
{
	debugfs_root = debugfs_create_dir("zcrypt", NULL);

	zcrypt_dbf_common = debug_register("zcrypt_common", 1, 1, 16);
	debug_register_view(zcrypt_dbf_common, &debug_hex_ascii_view);
	debug_set_level(zcrypt_dbf_common, DBF_ERR);

	zcrypt_dbf_devices = debug_register("zcrypt_devices", 1, 1, 16);
	debug_register_view(zcrypt_dbf_devices, &debug_hex_ascii_view);
	debug_set_level(zcrypt_dbf_devices, DBF_ERR);

	return 0;
}

void zcrypt_debug_exit(void)
{
	debugfs_remove(debugfs_root);
	if (zcrypt_dbf_common)
		debug_unregister(zcrypt_dbf_common);
	if (zcrypt_dbf_devices)
		debug_unregister(zcrypt_dbf_devices);
}

/**
 * zcrypt_api_init(): Module initialization.
 *
 * The module initialization code.
 */
int __init zcrypt_api_init(void)
{
	int rc;

	rc = zcrypt_debug_init();
	if (rc)
		goto out;

	atomic_set(&zcrypt_rescan_req, 0);

	/* Register the request sprayer. */
	rc = misc_register(&zcrypt_misc_device);
	if (rc < 0)
		goto out;

	/* Set up the proc file system */
	zcrypt_entry = proc_create("driver/z90crypt", 0644, NULL, &zcrypt_proc_fops);
	if (!zcrypt_entry) {
		rc = -ENOMEM;
		goto out_misc;
	}

	return 0;

out_misc:
	misc_deregister(&zcrypt_misc_device);
out:
	return rc;
}

/**
 * zcrypt_api_exit(): Module termination.
 *
 * The module termination code.
 */
void zcrypt_api_exit(void)
{
	remove_proc_entry("driver/z90crypt", NULL);
	misc_deregister(&zcrypt_misc_device);
	zcrypt_debug_exit();
}

module_init(zcrypt_api_init);
module_exit(zcrypt_api_exit);