Linux Kernel  3.7.1
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tpm-rng.c
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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 
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 
36 static int __init rng_init(void)
37 {
38  return hwrng_register(&tpm_rng);
39 }
40 module_init(rng_init);
41 
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 <[email protected]>");
50 MODULE_DESCRIPTION("RNG driver for TPM devices");