1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * Copyright (C) 2010 Michael Neuling IBM Corporation
 4 *
 5 * Driver for the pseries hardware RNG for POWER7+ and above
 
 
 
 
 
 
 
 
 
 
 
 
 
 6 */
 7
 8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/hw_random.h>
13#include <asm/vio.h>
14
 
15
16static int pseries_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
17{
18	u64 buffer[PLPAR_HCALL_BUFSIZE];
19	int rc;
20
21	rc = plpar_hcall(H_RANDOM, (unsigned long *)buffer);
22	if (rc != H_SUCCESS) {
23		pr_err_ratelimited("H_RANDOM call failed %d\n", rc);
24		return -EIO;
25	}
26	memcpy(data, buffer, 8);
27
28	/* The hypervisor interface returns 64 bits */
29	return 8;
30}
31
32/*
33 * pseries_rng_get_desired_dma - Return desired DMA allocate for CMO operations
34 *
35 * This is a required function for a driver to operate in a CMO environment
36 * but this device does not make use of DMA allocations, return 0.
37 *
38 * Return value:
39 *	Number of bytes of IO data the driver will need to perform well -> 0
40 */
41static unsigned long pseries_rng_get_desired_dma(struct vio_dev *vdev)
42{
43	return 0;
44};
45
46static struct hwrng pseries_rng = {
47	.name		= KBUILD_MODNAME,
48	.read		= pseries_rng_read,
49};
50
51static int pseries_rng_probe(struct vio_dev *dev,
52		const struct vio_device_id *id)
53{
54	return hwrng_register(&pseries_rng);
55}
56
57static void pseries_rng_remove(struct vio_dev *dev)
58{
59	hwrng_unregister(&pseries_rng);
 
60}
61
62static const struct vio_device_id pseries_rng_driver_ids[] = {
63	{ "ibm,random-v1", "ibm,random"},
64	{ "", "" }
65};
66MODULE_DEVICE_TABLE(vio, pseries_rng_driver_ids);
67
68static struct vio_driver pseries_rng_driver = {
69	.name = KBUILD_MODNAME,
70	.probe = pseries_rng_probe,
71	.remove = pseries_rng_remove,
72	.get_desired_dma = pseries_rng_get_desired_dma,
73	.id_table = pseries_rng_driver_ids
74};
75
76static int __init rng_init(void)
77{
78	pr_info("Registering IBM pSeries RNG driver\n");
79	return vio_register_driver(&pseries_rng_driver);
80}
81
82module_init(rng_init);
83
84static void __exit rng_exit(void)
85{
86	vio_unregister_driver(&pseries_rng_driver);
87}
88module_exit(rng_exit);
89
90MODULE_LICENSE("GPL");
91MODULE_AUTHOR("Michael Neuling <mikey@neuling.org>");
92MODULE_DESCRIPTION("H/W RNG driver for IBM pSeries processors");

 
 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");