blob: c422e870dc52705cf779fe7742706bca3eaad86c [file] [log] [blame]
Michael Buesch96d63c02006-06-26 00:25:00 -07001/*
2 * RNG driver for AMD RNGs
3 *
4 * Copyright 2005 (c) MontaVista Software, Inc.
5 *
6 * with the majority of the code coming from:
7 *
8 * Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
9 * (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
10 *
11 * derived from
12 *
13 * Hardware driver for the AMD 768 Random Number Generator (RNG)
14 * (c) Copyright 2001 Red Hat Inc <alan@redhat.com>
15 *
16 * derived from
17 *
18 * Hardware driver for Intel i810 Random Number Generator (RNG)
19 * Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
20 * Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
21 *
22 * This file is licensed under the terms of the GNU General Public
23 * License version 2. This program is licensed "as is" without any
24 * warranty of any kind, whether express or implied.
25 */
26
27#include <linux/module.h>
28#include <linux/kernel.h>
29#include <linux/pci.h>
30#include <linux/hw_random.h>
Patrick McHardy984e9762007-11-21 12:24:45 +080031#include <linux/delay.h>
Michael Buesch96d63c02006-06-26 00:25:00 -070032#include <asm/io.h>
33
34
35#define PFX KBUILD_MODNAME ": "
36
37
38/*
39 * Data for PCI driver interface
40 *
41 * This data only exists for exporting the supported
42 * PCI ids via MODULE_DEVICE_TABLE. We do not actually
43 * register a pci_driver, because someone else might one day
44 * want to register another driver on the same PCI id.
45 */
46static const struct pci_device_id pci_tbl[] = {
47 { 0x1022, 0x7443, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, },
48 { 0x1022, 0x746b, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, },
49 { 0, }, /* terminate list */
50};
51MODULE_DEVICE_TABLE(pci, pci_tbl);
52
53static struct pci_dev *amd_pdev;
54
55
Patrick McHardy984e9762007-11-21 12:24:45 +080056static int amd_rng_data_present(struct hwrng *rng, int wait)
Michael Buesch96d63c02006-06-26 00:25:00 -070057{
58 u32 pmbase = (u32)rng->priv;
Patrick McHardy984e9762007-11-21 12:24:45 +080059 int data, i;
Michael Buesch96d63c02006-06-26 00:25:00 -070060
Patrick McHardy984e9762007-11-21 12:24:45 +080061 for (i = 0; i < 20; i++) {
62 data = !!(inl(pmbase + 0xF4) & 1);
63 if (data || !wait)
64 break;
65 udelay(10);
66 }
67 return data;
Michael Buesch96d63c02006-06-26 00:25:00 -070068}
69
70static int amd_rng_data_read(struct hwrng *rng, u32 *data)
71{
72 u32 pmbase = (u32)rng->priv;
73
74 *data = inl(pmbase + 0xF0);
75
76 return 4;
77}
78
79static int amd_rng_init(struct hwrng *rng)
80{
81 u8 rnen;
82
83 pci_read_config_byte(amd_pdev, 0x40, &rnen);
84 rnen |= (1 << 7); /* RNG on */
85 pci_write_config_byte(amd_pdev, 0x40, rnen);
86
87 pci_read_config_byte(amd_pdev, 0x41, &rnen);
88 rnen |= (1 << 7); /* PMIO enable */
89 pci_write_config_byte(amd_pdev, 0x41, rnen);
90
91 return 0;
92}
93
94static void amd_rng_cleanup(struct hwrng *rng)
95{
96 u8 rnen;
97
98 pci_read_config_byte(amd_pdev, 0x40, &rnen);
99 rnen &= ~(1 << 7); /* RNG off */
100 pci_write_config_byte(amd_pdev, 0x40, rnen);
101}
102
103
104static struct hwrng amd_rng = {
105 .name = "amd",
106 .init = amd_rng_init,
107 .cleanup = amd_rng_cleanup,
108 .data_present = amd_rng_data_present,
109 .data_read = amd_rng_data_read,
110};
111
112
113static int __init mod_init(void)
114{
115 int err = -ENODEV;
116 struct pci_dev *pdev = NULL;
117 const struct pci_device_id *ent;
118 u32 pmbase;
119
120 for_each_pci_dev(pdev) {
121 ent = pci_match_id(pci_tbl, pdev);
122 if (ent)
123 goto found;
124 }
125 /* Device not found. */
126 goto out;
127
128found:
129 err = pci_read_config_dword(pdev, 0x58, &pmbase);
130 if (err)
131 goto out;
132 err = -EIO;
133 pmbase &= 0x0000FF00;
134 if (pmbase == 0)
135 goto out;
136 amd_rng.priv = (unsigned long)pmbase;
137 amd_pdev = pdev;
138
139 printk(KERN_INFO "AMD768 RNG detected\n");
140 err = hwrng_register(&amd_rng);
141 if (err) {
142 printk(KERN_ERR PFX "RNG registering failed (%d)\n",
143 err);
144 goto out;
145 }
146out:
147 return err;
148}
149
150static void __exit mod_exit(void)
151{
152 hwrng_unregister(&amd_rng);
153}
154
Michael Buesch56fb5fe2007-01-10 23:15:43 -0800155module_init(mod_init);
Michael Buesch96d63c02006-06-26 00:25:00 -0700156module_exit(mod_exit);
157
158MODULE_AUTHOR("The Linux Kernel team");
159MODULE_DESCRIPTION("H/W RNG driver for AMD chipsets");
160MODULE_LICENSE("GPL");