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/*
* 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 <linux/delay.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, int wait)
{
void __iomem *mem = (void __iomem *)rng->priv;
int data, i;
for (i = 0; i < 20; i++) {
data = !!(readl(mem + GEODE_RNG_STATUS_REG));
if (data || !wait)
break;
udelay(10);
}
return data;
}
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 err_unmap;
}
out:
return err;
err_unmap:
iounmap(mem);
goto out;
}
static void __exit mod_exit(void)
{
void __iomem *mem = (void __iomem *)geode_rng.priv;
hwrng_unregister(&geode_rng);
iounmap(mem);
}
module_init(mod_init);
module_exit(mod_exit);
MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs");
MODULE_LICENSE("GPL");
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