tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2010 Michael Neuling IBM Corporation
3 *
4 * Driver for the pseries hardware RNG for POWER7+ and above
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20#include <linux/module.h>
21#include <linux/hw_random.h>
22#include <asm/vio.h>
23
24#define MODULE_NAME "pseries-rng"
25
26static int pseries_rng_data_read(struct hwrng *rng, u32 *data)
27{
28 if (plpar_hcall(H_RANDOM, (unsigned long *)data) != H_SUCCESS) {
29 printk(KERN_ERR "pseries rng hcall error\n");
30 return 0;
31 }
32 return 8;
33}
34
35/**
36 * pseries_rng_get_desired_dma - Return desired DMA allocate for CMO operations
37 *
38 * This is a required function for a driver to operate in a CMO environment
39 * but this device does not make use of DMA allocations, return 0.
40 *
41 * Return value:
42 * Number of bytes of IO data the driver will need to perform well -> 0
43 */
44static unsigned long pseries_rng_get_desired_dma(struct vio_dev *vdev)
45{
46 return 0;
47};
48
49static struct hwrng pseries_rng = {
50 .name = MODULE_NAME,
51 .data_read = pseries_rng_data_read,
52};
53
54static int __init pseries_rng_probe(struct vio_dev *dev,
55 const struct vio_device_id *id)
56{
57 return hwrng_register(&pseries_rng);
58}
59
60static int __exit pseries_rng_remove(struct vio_dev *dev)
61{
62 hwrng_unregister(&pseries_rng);
63 return 0;
64}
65
66static struct vio_device_id pseries_rng_driver_ids[] = {
67 { "ibm,random-v1", "ibm,random"},
68 { "", "" }
69};
70MODULE_DEVICE_TABLE(vio, pseries_rng_driver_ids);
71
72static struct vio_driver pseries_rng_driver = {
73 .name = MODULE_NAME,
74 .probe = pseries_rng_probe,
75 .remove = pseries_rng_remove,
76 .get_desired_dma = pseries_rng_get_desired_dma,
77 .id_table = pseries_rng_driver_ids
78};
79
80static int __init rng_init(void)
81{
82 printk(KERN_INFO "Registering IBM pSeries RNG driver\n");
83 return vio_register_driver(&pseries_rng_driver);
84}
85
86module_init(rng_init);
87
88static void __exit rng_exit(void)
89{
90 vio_unregister_driver(&pseries_rng_driver);
91}
92module_exit(rng_exit);
93
94MODULE_LICENSE("GPL");
95MODULE_AUTHOR("Michael Neuling <mikey@neuling.org>");
96MODULE_DESCRIPTION("H/W RNG driver for IBM pSeries processors");