powerpc/pseries/hwrng: PFO-based hwrng driver

Adds support for the Platform Facilities Option (PFO)-based hardware
random number generator for POWER hardware.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Kent Yoder 2012-04-12 05:08:53 +00:00 committed by Benjamin Herrenschmidt
parent f2ab621996
commit 649e9ea0ab
3 changed files with 110 additions and 0 deletions

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@ -250,3 +250,16 @@ config UML_RANDOM
(check your distro, or download from
http://sourceforge.net/projects/gkernel/). rngd periodically reads
/dev/hwrng and injects the entropy into /dev/random.
config HW_RANDOM_PSERIES
tristate "pSeries HW Random Number Generator support"
depends on HW_RANDOM && PPC64 && IBMVIO
default HW_RANDOM
---help---
This driver provides kernel-side support for the Random Number
Generator hardware found on POWER7+ machines and above
To compile this driver as a module, choose M here: the
module will be called pseries-rng.
If unsure, say Y.

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@ -22,3 +22,4 @@ obj-$(CONFIG_HW_RANDOM_OCTEON) += octeon-rng.o
obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
obj-$(CONFIG_HW_RANDOM_PICOXCELL) += picoxcell-rng.o
obj-$(CONFIG_HW_RANDOM_PPC4XX) += ppc4xx-rng.o
obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o

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@ -0,0 +1,96 @@
/*
* Copyright (C) 2010 Michael Neuling IBM Corporation
*
* Driver for the pseries hardware RNG for POWER7+ and above
*
* 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 <linux/module.h>
#include <linux/hw_random.h>
#include <asm/vio.h>
#define MODULE_NAME "pseries-rng"
static int pseries_rng_data_read(struct hwrng *rng, u32 *data)
{
if (plpar_hcall(H_RANDOM, (unsigned long *)data) != H_SUCCESS) {
printk(KERN_ERR "pseries rng hcall error\n");
return 0;
}
return 8;
}
/**
* pseries_rng_get_desired_dma - Return desired DMA allocate for CMO operations
*
* This is a required function for a driver to operate in a CMO environment
* but this device does not make use of DMA allocations, return 0.
*
* Return value:
* Number of bytes of IO data the driver will need to perform well -> 0
*/
static unsigned long pseries_rng_get_desired_dma(struct vio_dev *vdev)
{
return 0;
};
static struct hwrng pseries_rng = {
.name = MODULE_NAME,
.data_read = pseries_rng_data_read,
};
static int __init pseries_rng_probe(struct vio_dev *dev,
const struct vio_device_id *id)
{
return hwrng_register(&pseries_rng);
}
static int __exit pseries_rng_remove(struct vio_dev *dev)
{
hwrng_unregister(&pseries_rng);
return 0;
}
static struct vio_device_id pseries_rng_driver_ids[] = {
{ "ibm,random-v1", "ibm,random"},
{ "", "" }
};
MODULE_DEVICE_TABLE(vio, pseries_rng_driver_ids);
static struct vio_driver pseries_rng_driver = {
.name = MODULE_NAME,
.probe = pseries_rng_probe,
.remove = pseries_rng_remove,
.get_desired_dma = pseries_rng_get_desired_dma,
.id_table = pseries_rng_driver_ids
};
static int __init rng_init(void)
{
printk(KERN_INFO "Registering IBM pSeries RNG driver\n");
return vio_register_driver(&pseries_rng_driver);
}
module_init(rng_init);
static void __exit rng_exit(void)
{
vio_unregister_driver(&pseries_rng_driver);
}
module_exit(rng_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michael Neuling <mikey@neuling.org>");
MODULE_DESCRIPTION("H/W RNG driver for IBM pSeries processors");