1 /*
2 * Copyright (C) 2012 Kent Yoder IBM Corporation
3 *
4 * HWRNG interfaces to pull RNG data from a TPM
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 <linux/tpm.h>
23
24 #define MODULE_NAME "tpm-rng"
25
tpm_rng_read(struct hwrng * rng,void * data,size_t max,bool wait)26 static int tpm_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
27 {
28 return tpm_get_random(TPM_ANY_NUM, data, max);
29 }
30
31 static struct hwrng tpm_rng = {
32 .name = MODULE_NAME,
33 .read = tpm_rng_read,
34 };
35
rng_init(void)36 static int __init rng_init(void)
37 {
38 return hwrng_register(&tpm_rng);
39 }
40 module_init(rng_init);
41
rng_exit(void)42 static void __exit rng_exit(void)
43 {
44 hwrng_unregister(&tpm_rng);
45 }
46 module_exit(rng_exit);
47
48 MODULE_LICENSE("GPL v2");
49 MODULE_AUTHOR("Kent Yoder <key@linux.vnet.ibm.com>");
50 MODULE_DESCRIPTION("RNG driver for TPM devices");
51