drivers/char/hw_random/tpm-rng.c

   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 <key@linux.vnet.ibm.com>");
  50 MODULE_DESCRIPTION("RNG driver for TPM devices");