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[PATCH] Add Geode HW RNG driver
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Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Michael Buesch authored and Linus Torvalds committed Jun 26, 2006
1 parent 96d63c0 commit ef5d862
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13 changes: 13 additions & 0 deletions drivers/char/hw_random/Kconfig
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Expand Up @@ -35,3 +35,16 @@ config HW_RANDOM_AMD
module will be called amd-rng.

If unsure, say Y.

config HW_RANDOM_GEODE
tristate "AMD Geode HW Random Number Generator support"
depends on HW_RANDOM && X86 && PCI
default y
---help---
This driver provides kernel-side support for the Random Number
Generator hardware found on the AMD Geode LX.

To compile this driver as a module, choose M here: the
module will be called geode-rng.

If unsure, say Y.
1 change: 1 addition & 0 deletions drivers/char/hw_random/Makefile
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Expand Up @@ -5,3 +5,4 @@
obj-$(CONFIG_HW_RANDOM) += core.o
obj-$(CONFIG_HW_RANDOM_INTEL) += intel-rng.o
obj-$(CONFIG_HW_RANDOM_AMD) += amd-rng.o
obj-$(CONFIG_HW_RANDOM_GEODE) += geode-rng.o
128 changes: 128 additions & 0 deletions drivers/char/hw_random/geode-rng.c
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@@ -0,0 +1,128 @@
/*
* RNG driver for AMD Geode RNGs
*
* Copyright 2005 (c) MontaVista Software, Inc.
*
* with the majority of the code coming from:
*
* Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
* (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
*
* derived from
*
* Hardware driver for the AMD 768 Random Number Generator (RNG)
* (c) Copyright 2001 Red Hat Inc <alan@redhat.com>
*
* derived from
*
* Hardware driver for Intel i810 Random Number Generator (RNG)
* Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
* Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/hw_random.h>
#include <asm/io.h>


#define PFX KBUILD_MODNAME ": "

#define GEODE_RNG_DATA_REG 0x50
#define GEODE_RNG_STATUS_REG 0x54

/*
* Data for PCI driver interface
*
* This data only exists for exporting the supported
* PCI ids via MODULE_DEVICE_TABLE. We do not actually
* register a pci_driver, because someone else might one day
* want to register another driver on the same PCI id.
*/
static const struct pci_device_id pci_tbl[] = {
{ PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_LX_AES,
PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, },
{ 0, }, /* terminate list */
};
MODULE_DEVICE_TABLE(pci, pci_tbl);


static int geode_rng_data_read(struct hwrng *rng, u32 *data)
{
void __iomem *mem = (void __iomem *)rng->priv;

*data = readl(mem + GEODE_RNG_DATA_REG);

return 4;
}

static int geode_rng_data_present(struct hwrng *rng)
{
void __iomem *mem = (void __iomem *)rng->priv;

return !!(readl(mem + GEODE_RNG_STATUS_REG));
}


static struct hwrng geode_rng = {
.name = "geode",
.data_present = geode_rng_data_present,
.data_read = geode_rng_data_read,
};


static int __init mod_init(void)
{
int err = -ENODEV;
struct pci_dev *pdev = NULL;
const struct pci_device_id *ent;
void __iomem *mem;
unsigned long rng_base;

for_each_pci_dev(pdev) {
ent = pci_match_id(pci_tbl, pdev);
if (ent)
goto found;
}
/* Device not found. */
goto out;

found:
rng_base = pci_resource_start(pdev, 0);
if (rng_base == 0)
goto out;
err = -ENOMEM;
mem = ioremap(rng_base, 0x58);
if (!mem)
goto out;
geode_rng.priv = (unsigned long)mem;

printk(KERN_INFO "AMD Geode RNG detected\n");
err = hwrng_register(&geode_rng);
if (err) {
printk(KERN_ERR PFX "RNG registering failed (%d)\n",
err);
goto out;
}
out:
return err;
}

static void __exit mod_exit(void)
{
void __iomem *mem = (void __iomem *)geode_rng.priv;

hwrng_unregister(&geode_rng);
iounmap(mem);
}

subsys_initcall(mod_init);
module_exit(mod_exit);

MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs");
MODULE_LICENSE("GPL");

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