Linux 4.2.1

[linux/fpc-iii.git] / 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)
{
        if (zops->owner) {
                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->owner->name, name, MODULE_NAME_LEN))) {
                        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 ||
            (crt->inputdatalength & 1))
                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)
{
        int r;

        seq_printf(m, "\n%s\n", title);
        for (r = 0; r < len; r++) {
                if ((r % 8) == 0)
                        seq_printf(m, "    ");
                seq_printf(m, "%08X ", array[r]);
                if ((r % 8) == 7)
                        seq_putc(m, '\n');
        }
        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);