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96d63c02 MB |
1 | /* |
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) | |
77122d0b | 14 | * (c) Copyright 2001 Red Hat Inc |
96d63c02 MB |
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> | |
984e976f | 31 | #include <linux/delay.h> |
96d63c02 MB |
32 | #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 | */ | |
46 | static const struct pci_device_id pci_tbl[] = { | |
409a7363 JP |
47 | { PCI_VDEVICE(AMD, 0x7443), 0, }, |
48 | { PCI_VDEVICE(AMD, 0x746b), 0, }, | |
96d63c02 MB |
49 | { 0, }, /* terminate list */ |
50 | }; | |
51 | MODULE_DEVICE_TABLE(pci, pci_tbl); | |
52 | ||
53 | static struct pci_dev *amd_pdev; | |
54 | ||
55 | ||
984e976f | 56 | static int amd_rng_data_present(struct hwrng *rng, int wait) |
96d63c02 MB |
57 | { |
58 | u32 pmbase = (u32)rng->priv; | |
984e976f PM |
59 | int data, i; |
60 | ||
61 | 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; | |
96d63c02 MB |
68 | } |
69 | ||
70 | static 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 | ||
79 | static 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 | ||
94 | static 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 | ||
104 | static 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 | ||
113 | static 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 | ||
128 | found: | |
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; | |
bd68ccb3 DES |
136 | if (!request_region(pmbase + 0xF0, 8, "AMD HWRNG")) { |
137 | dev_err(&pdev->dev, "AMD HWRNG region 0x%x already in use!\n", | |
138 | pmbase + 0xF0); | |
139 | err = -EBUSY; | |
140 | goto out; | |
141 | } | |
96d63c02 MB |
142 | amd_rng.priv = (unsigned long)pmbase; |
143 | amd_pdev = pdev; | |
144 | ||
7a1ae9c0 | 145 | pr_info("AMD768 RNG detected\n"); |
96d63c02 MB |
146 | err = hwrng_register(&amd_rng); |
147 | if (err) { | |
7a1ae9c0 | 148 | pr_err(PFX "RNG registering failed (%d)\n", |
96d63c02 | 149 | err); |
bd68ccb3 | 150 | release_region(pmbase + 0xF0, 8); |
96d63c02 MB |
151 | goto out; |
152 | } | |
153 | out: | |
154 | return err; | |
155 | } | |
156 | ||
157 | static void __exit mod_exit(void) | |
158 | { | |
bd68ccb3 DES |
159 | u32 pmbase = (unsigned long)amd_rng.priv; |
160 | release_region(pmbase + 0xF0, 8); | |
96d63c02 MB |
161 | hwrng_unregister(&amd_rng); |
162 | } | |
163 | ||
56fb5fe9 | 164 | module_init(mod_init); |
96d63c02 MB |
165 | module_exit(mod_exit); |
166 | ||
167 | MODULE_AUTHOR("The Linux Kernel team"); | |
168 | MODULE_DESCRIPTION("H/W RNG driver for AMD chipsets"); | |
169 | MODULE_LICENSE("GPL"); |