1/*
2 * drivers/char/hw_random/ixp4xx-rng.c
3 *
4 * RNG driver for Intel IXP4xx family of NPUs
5 *
6 * Author: Deepak Saxena <dsaxena@plexity.net>
7 *
8 * Copyright 2005 (c) MontaVista Software, Inc.
9 *
10 * Fixes by Michael Buesch
11 *
12 * This file is licensed under  the terms of the GNU General Public
13 * License version 2. This program is licensed "as is" without any
14 * warranty of any kind, whether express or implied.
15 */
16
17#include <linux/kernel.h>
18#include <linux/types.h>
19#include <linux/module.h>
20#include <linux/moduleparam.h>
21#include <linux/init.h>
22#include <linux/bitops.h>
23#include <linux/hw_random.h>
24
25#include <asm/io.h>
26#include <mach/hardware.h>
27
28
29static int ixp4xx_rng_data_read(struct hwrng *rng, u32 *buffer)
30{
31	void __iomem * rng_base = (void __iomem *)rng->priv;
32
33	*buffer = __raw_readl(rng_base);
34
35	return 4;
36}
37
38static struct hwrng ixp4xx_rng_ops = {
39	.name		= "ixp4xx",
40	.data_read	= ixp4xx_rng_data_read,
41};
42
43static int __init ixp4xx_rng_init(void)
44{
45	void __iomem * rng_base;
46	int err;
47
48	if (!cpu_is_ixp46x()) /* includes IXP455 */
49		return -ENOSYS;
50
51	rng_base = ioremap(0x70002100, 4);
52	if (!rng_base)
53		return -ENOMEM;
54	ixp4xx_rng_ops.priv = (unsigned long)rng_base;
55	err = hwrng_register(&ixp4xx_rng_ops);
56	if (err)
57		iounmap(rng_base);
58
59	return err;
60}
61
62static void __exit ixp4xx_rng_exit(void)
63{
64	void __iomem * rng_base = (void __iomem *)ixp4xx_rng_ops.priv;
65
66	hwrng_unregister(&ixp4xx_rng_ops);
67	iounmap(rng_base);
68}
69
70module_init(ixp4xx_rng_init);
71module_exit(ixp4xx_rng_exit);
72
73MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
74MODULE_DESCRIPTION("H/W Pseudo-Random Number Generator (RNG) driver for IXP45x/46x");
75MODULE_LICENSE("GPL");
76