Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Open Menu / drivers / char / hw_random / geode-rng.c
Loading...
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
/*
 * 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 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");