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ef5d8627 MB |
1 | /* |
2 | * RNG driver for AMD Geode 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 |
ef5d8627 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 | ||
e9afc746 PM |
27 | #include <linux/delay.h> |
28 | #include <linux/hw_random.h> | |
29 | #include <linux/io.h> | |
ef5d8627 | 30 | #include <linux/kernel.h> |
e9afc746 | 31 | #include <linux/module.h> |
ef5d8627 | 32 | #include <linux/pci.h> |
ef5d8627 | 33 | |
8c75704e PB |
34 | |
35 | #define PFX KBUILD_MODNAME ": " | |
36 | ||
ef5d8627 MB |
37 | #define GEODE_RNG_DATA_REG 0x50 |
38 | #define GEODE_RNG_STATUS_REG 0x54 | |
39 | ||
40 | /* | |
41 | * Data for PCI driver interface | |
42 | * | |
43 | * This data only exists for exporting the supported | |
44 | * PCI ids via MODULE_DEVICE_TABLE. We do not actually | |
45 | * register a pci_driver, because someone else might one day | |
46 | * want to register another driver on the same PCI id. | |
47 | */ | |
48 | static const struct pci_device_id pci_tbl[] = { | |
409a7363 | 49 | { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), 0, }, |
ef5d8627 MB |
50 | { 0, }, /* terminate list */ |
51 | }; | |
52 | MODULE_DEVICE_TABLE(pci, pci_tbl); | |
53 | ||
54 | ||
55 | static int geode_rng_data_read(struct hwrng *rng, u32 *data) | |
56 | { | |
57 | void __iomem *mem = (void __iomem *)rng->priv; | |
58 | ||
59 | *data = readl(mem + GEODE_RNG_DATA_REG); | |
60 | ||
61 | return 4; | |
62 | } | |
63 | ||
984e976f | 64 | static int geode_rng_data_present(struct hwrng *rng, int wait) |
ef5d8627 MB |
65 | { |
66 | void __iomem *mem = (void __iomem *)rng->priv; | |
984e976f | 67 | int data, i; |
ef5d8627 | 68 | |
984e976f PM |
69 | for (i = 0; i < 20; i++) { |
70 | data = !!(readl(mem + GEODE_RNG_STATUS_REG)); | |
71 | if (data || !wait) | |
72 | break; | |
73 | udelay(10); | |
74 | } | |
75 | return data; | |
ef5d8627 MB |
76 | } |
77 | ||
78 | ||
79 | static struct hwrng geode_rng = { | |
80 | .name = "geode", | |
81 | .data_present = geode_rng_data_present, | |
82 | .data_read = geode_rng_data_read, | |
83 | }; | |
84 | ||
85 | ||
86 | static int __init mod_init(void) | |
87 | { | |
8c75704e | 88 | int err = -ENODEV; |
ef5d8627 MB |
89 | struct pci_dev *pdev = NULL; |
90 | const struct pci_device_id *ent; | |
91 | void __iomem *mem; | |
92 | unsigned long rng_base; | |
93 | ||
94 | for_each_pci_dev(pdev) { | |
95 | ent = pci_match_id(pci_tbl, pdev); | |
8c75704e PB |
96 | if (ent) |
97 | goto found; | |
ef5d8627 | 98 | } |
6e9b5e76 | 99 | /* Device not found. */ |
8c75704e PB |
100 | goto out; |
101 | ||
102 | found: | |
103 | rng_base = pci_resource_start(pdev, 0); | |
104 | if (rng_base == 0) | |
105 | goto out; | |
106 | err = -ENOMEM; | |
107 | mem = ioremap(rng_base, 0x58); | |
108 | if (!mem) | |
109 | goto out; | |
110 | geode_rng.priv = (unsigned long)mem; | |
111 | ||
112 | pr_info("AMD Geode RNG detected\n"); | |
113 | err = hwrng_register(&geode_rng); | |
114 | if (err) { | |
115 | pr_err(PFX "RNG registering failed (%d)\n", | |
116 | err); | |
117 | goto err_unmap; | |
118 | } | |
119 | out: | |
120 | return err; | |
121 | ||
122 | err_unmap: | |
123 | iounmap(mem); | |
124 | goto out; | |
ef5d8627 MB |
125 | } |
126 | ||
127 | static void __exit mod_exit(void) | |
128 | { | |
8c75704e PB |
129 | void __iomem *mem = (void __iomem *)geode_rng.priv; |
130 | ||
131 | hwrng_unregister(&geode_rng); | |
132 | iounmap(mem); | |
ef5d8627 MB |
133 | } |
134 | ||
56fb5fe9 | 135 | module_init(mod_init); |
ef5d8627 MB |
136 | module_exit(mod_exit); |
137 | ||
138 | MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs"); | |
139 | MODULE_LICENSE("GPL"); |