From 578b016fdc91464c08c096f0c5952cae549fdb8f Mon Sep 17 00:00:00 2001 From: Kent Yoder Date: Wed, 8 Aug 2012 14:18:57 -0500 Subject: hw_random: add support for the TPM chip as a hardware RNG source This driver will make use of any available TPM chip on the system as a hwrng source. Acked-by: David Safford Signed-off-by: Kent Yoder --- drivers/char/hw_random/tpm-rng.c | 50 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 drivers/char/hw_random/tpm-rng.c (limited to 'drivers/char/hw_random/tpm-rng.c') diff --git a/drivers/char/hw_random/tpm-rng.c b/drivers/char/hw_random/tpm-rng.c new file mode 100644 index 000000000000..d6d448266f07 --- /dev/null +++ b/drivers/char/hw_random/tpm-rng.c @@ -0,0 +1,50 @@ +/* + * Copyright (C) 2012 Kent Yoder IBM Corporation + * + * HWRNG interfaces to pull RNG data from a TPM + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include + +#define MODULE_NAME "tpm-rng" + +static int tpm_rng_read(struct hwrng *rng, void *data, size_t max, bool wait) +{ + return tpm_get_random(TPM_ANY_NUM, data, max); +} + +static struct hwrng tpm_rng = { + .name = MODULE_NAME, + .read = tpm_rng_read, +}; + +static int __init rng_init(void) +{ + return hwrng_register(&tpm_rng); +} +module_init(rng_init); + +static void __exit rng_exit(void) +{ + hwrng_unregister(&tpm_rng); +} +module_exit(rng_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Kent Yoder "); +MODULE_DESCRIPTION("RNG driver for TPM devices"); -- cgit v1.2.3-59-g8ed1b