path: root/drivers/s390/crypto/zcrypt_api.c

/*
 *  linux/drivers/s390/crypto/zcrypt_api.c
 *
 *  zcrypt 2.1.0
 *
 *  Copyright (C)  2001, 2006 IBM Corporation
 *  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>
 *
 * 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/compat.h>
#include <asm/atomic.h>
#include <asm/uaccess.h>

#include "zcrypt_api.h"

/**
 * Module description.
 */
MODULE_AUTHOR("IBM Corporation");
MODULE_DESCRIPTION("Cryptographic Coprocessor interface, "
		   "Copyright 2001, 2006 IBM Corporation");
MODULE_LICENSE("GPL");

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);

/**
 * 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;
	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,
};

/**
 * 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_del(&zdev->list);
	list_add(&zdev->list, l);
}

/**
 * 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