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authorMichael Buesch <mb@bu3sch.de>2006-06-26 03:24:59 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-26 12:58:19 -0400
commitca644bd5039566725b7c71a559e65ea91b7abfb5 (patch)
treebb742631c38a676267750d194ed6053489acfd88 /drivers/char
parent844dd05fec172d98b0dacecd9b9e9f6595204c13 (diff)
[PATCH] Add Intel HW RNG driver
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>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/hw_random/Kconfig13
-rw-r--r--drivers/char/hw_random/Makefile1
-rw-r--r--drivers/char/hw_random/intel-rng.c189
3 files changed, 203 insertions, 0 deletions
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index fa4a245127ad..e9ae4b1313a7 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -9,3 +9,16 @@ config HW_RANDOM
9 Hardware Random Number Generator Core infrastructure. 9 Hardware Random Number Generator Core infrastructure.
10 10
11 If unsure, say Y. 11 If unsure, say Y.
12
13config HW_RANDOM_INTEL
14 tristate "Intel HW Random Number Generator support"
15 depends on HW_RANDOM && (X86 || IA64) && PCI
16 default y
17 ---help---
18 This driver provides kernel-side support for the Random Number
19 Generator hardware found on Intel i8xx-based motherboards.
20
21 To compile this driver as a module, choose M here: the
22 module will be called intel-rng.
23
24 If unsure, say Y.
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index aa752af468ce..d3118e3750a4 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -3,3 +3,4 @@
3# 3#
4 4
5obj-$(CONFIG_HW_RANDOM) += core.o 5obj-$(CONFIG_HW_RANDOM) += core.o
6obj-$(CONFIG_HW_RANDOM_INTEL) += intel-rng.o
diff --git a/drivers/char/hw_random/intel-rng.c b/drivers/char/hw_random/intel-rng.c
new file mode 100644
index 000000000000..6594bd5645f4
--- /dev/null
+++ b/drivers/char/hw_random/intel-rng.c
@@ -0,0 +1,189 @@
1/*
2 * RNG driver for Intel 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>
31#include <asm/io.h>
32
33
34#define PFX KBUILD_MODNAME ": "
35
36/*
37 * RNG registers
38 */
39#define INTEL_RNG_HW_STATUS 0
40#define INTEL_RNG_PRESENT 0x40
41#define INTEL_RNG_ENABLED 0x01
42#define INTEL_RNG_STATUS 1
43#define INTEL_RNG_DATA_PRESENT 0x01
44#define INTEL_RNG_DATA 2
45
46/*
47 * Magic address at which Intel PCI bridges locate the RNG
48 */
49#define INTEL_RNG_ADDR 0xFFBC015F
50#define INTEL_RNG_ADDR_LEN 3
51
52/*
53 * Data for PCI driver interface
54 *
55 * This data only exists for exporting the supported
56 * PCI ids via MODULE_DEVICE_TABLE. We do not actually
57 * register a pci_driver, because someone else might one day
58 * want to register another driver on the same PCI id.
59 */
60static const struct pci_device_id pci_tbl[] = {
61 { 0x8086, 0x2418, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, },
62 { 0x8086, 0x2428, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, },
63 { 0x8086, 0x2430, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, },
64 { 0x8086, 0x2448, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, },
65 { 0x8086, 0x244e, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, },
66 { 0x8086, 0x245e, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, },
67 { 0, }, /* terminate list */
68};
69MODULE_DEVICE_TABLE(pci, pci_tbl);
70
71
72static inline u8 hwstatus_get(void __iomem *mem)
73{
74 return readb(mem + INTEL_RNG_HW_STATUS);
75}
76
77static inline u8 hwstatus_set(void __iomem *mem,
78 u8 hw_status)
79{
80 writeb(hw_status, mem + INTEL_RNG_HW_STATUS);
81 return hwstatus_get(mem);
82}
83
84static int intel_rng_data_present(struct hwrng *rng)
85{
86 void __iomem *mem = (void __iomem *)rng->priv;
87
88 return !!(readb(mem + INTEL_RNG_STATUS) & INTEL_RNG_DATA_PRESENT);
89}
90
91static int intel_rng_data_read(struct hwrng *rng, u32 *data)
92{
93 void __iomem *mem = (void __iomem *)rng->priv;
94
95 *data = readb(mem + INTEL_RNG_DATA);
96
97 return 1;
98}
99
100static int intel_rng_init(struct hwrng *rng)
101{
102 void __iomem *mem = (void __iomem *)rng->priv;
103 u8 hw_status;
104 int err = -EIO;
105
106 hw_status = hwstatus_get(mem);
107 /* turn RNG h/w on, if it's off */
108 if ((hw_status & INTEL_RNG_ENABLED) == 0)
109 hw_status = hwstatus_set(mem, hw_status | INTEL_RNG_ENABLED);
110 if ((hw_status & INTEL_RNG_ENABLED) == 0) {
111 printk(KERN_ERR PFX "cannot enable RNG, aborting\n");
112 goto out;
113 }
114 err = 0;
115out:
116 return err;
117}
118
119static void intel_rng_cleanup(struct hwrng *rng)
120{
121 void __iomem *mem = (void __iomem *)rng->priv;
122 u8 hw_status;
123
124 hw_status = hwstatus_get(mem);
125 if (hw_status & INTEL_RNG_ENABLED)
126 hwstatus_set(mem, hw_status & ~INTEL_RNG_ENABLED);
127 else
128 printk(KERN_WARNING PFX "unusual: RNG already disabled\n");
129}
130
131
132static struct hwrng intel_rng = {
133 .name = "intel",
134 .init = intel_rng_init,
135 .cleanup = intel_rng_cleanup,
136 .data_present = intel_rng_data_present,
137 .data_read = intel_rng_data_read,
138};
139
140
141static int __init mod_init(void)
142{
143 int err = -ENODEV;
144 void __iomem *mem;
145 u8 hw_status;
146
147 if (!pci_dev_present(pci_tbl))
148 goto out; /* Device not found. */
149
150 err = -ENOMEM;
151 mem = ioremap(INTEL_RNG_ADDR, INTEL_RNG_ADDR_LEN);
152 if (!mem)
153 goto out;
154 intel_rng.priv = (unsigned long)mem;
155
156 /* Check for Intel 82802 */
157 err = -ENODEV;
158 hw_status = hwstatus_get(mem);
159 if ((hw_status & INTEL_RNG_PRESENT) == 0)
160 goto err_unmap;
161
162 printk(KERN_INFO "Intel 82802 RNG detected\n");
163 err = hwrng_register(&intel_rng);
164 if (err) {
165 printk(KERN_ERR PFX "RNG registering failed (%d)\n",
166 err);
167 goto out;
168 }
169out:
170 return err;
171
172err_unmap:
173 iounmap(mem);
174 goto out;
175}
176
177static void __exit mod_exit(void)
178{
179 void __iomem *mem = (void __iomem *)intel_rng.priv;
180
181 hwrng_unregister(&intel_rng);
182 iounmap(mem);
183}
184
185subsys_initcall(mod_init);
186module_exit(mod_exit);
187
188MODULE_DESCRIPTION("H/W RNG driver for Intel chipsets");
189MODULE_LICENSE("GPL");