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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) | |
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> | |
984e976f | 31 | #include <linux/delay.h> |
ef5d8627 MB |
32 | #include <asm/io.h> |
33 | ||
34 | ||
35 | #define PFX KBUILD_MODNAME ": " | |
36 | ||
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[] = { | |
49 | { PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_LX_AES, | |
50 | PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, }, | |
51 | { 0, }, /* terminate list */ | |
52 | }; | |
53 | MODULE_DEVICE_TABLE(pci, pci_tbl); | |
54 | ||
55 | ||
56 | static int geode_rng_data_read(struct hwrng *rng, u32 *data) | |
57 | { | |
58 | void __iomem *mem = (void __iomem *)rng->priv; | |
59 | ||
60 | *data = readl(mem + GEODE_RNG_DATA_REG); | |
61 | ||
62 | return 4; | |
63 | } | |
64 | ||
984e976f | 65 | static int geode_rng_data_present(struct hwrng *rng, int wait) |
ef5d8627 MB |
66 | { |
67 | void __iomem *mem = (void __iomem *)rng->priv; | |
984e976f | 68 | int data, i; |
ef5d8627 | 69 | |
984e976f PM |
70 | for (i = 0; i < 20; i++) { |
71 | data = !!(readl(mem + GEODE_RNG_STATUS_REG)); | |
72 | if (data || !wait) | |
73 | break; | |
74 | udelay(10); | |
75 | } | |
76 | return data; | |
ef5d8627 MB |
77 | } |
78 | ||
79 | ||
80 | static struct hwrng geode_rng = { | |
81 | .name = "geode", | |
82 | .data_present = geode_rng_data_present, | |
83 | .data_read = geode_rng_data_read, | |
84 | }; | |
85 | ||
86 | ||
87 | static int __init mod_init(void) | |
88 | { | |
89 | int err = -ENODEV; | |
90 | struct pci_dev *pdev = NULL; | |
91 | const struct pci_device_id *ent; | |
92 | void __iomem *mem; | |
93 | unsigned long rng_base; | |
94 | ||
95 | for_each_pci_dev(pdev) { | |
96 | ent = pci_match_id(pci_tbl, pdev); | |
97 | if (ent) | |
98 | goto found; | |
99 | } | |
100 | /* Device not found. */ | |
101 | goto out; | |
102 | ||
103 | found: | |
104 | rng_base = pci_resource_start(pdev, 0); | |
105 | if (rng_base == 0) | |
106 | goto out; | |
107 | err = -ENOMEM; | |
108 | mem = ioremap(rng_base, 0x58); | |
109 | if (!mem) | |
110 | goto out; | |
111 | geode_rng.priv = (unsigned long)mem; | |
112 | ||
113 | printk(KERN_INFO "AMD Geode RNG detected\n"); | |
114 | err = hwrng_register(&geode_rng); | |
115 | if (err) { | |
116 | printk(KERN_ERR PFX "RNG registering failed (%d)\n", | |
117 | err); | |
072d3d1a | 118 | goto err_unmap; |
ef5d8627 MB |
119 | } |
120 | out: | |
121 | return err; | |
072d3d1a MB |
122 | |
123 | err_unmap: | |
124 | iounmap(mem); | |
125 | goto out; | |
ef5d8627 MB |
126 | } |
127 | ||
128 | static void __exit mod_exit(void) | |
129 | { | |
130 | void __iomem *mem = (void __iomem *)geode_rng.priv; | |
131 | ||
132 | hwrng_unregister(&geode_rng); | |
133 | iounmap(mem); | |
134 | } | |
135 | ||
56fb5fe9 | 136 | module_init(mod_init); |
ef5d8627 MB |
137 | module_exit(mod_exit); |
138 | ||
139 | MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs"); | |
140 | MODULE_LICENSE("GPL"); |