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 |
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/delay.h> |
28 | #include <linux/hw_random.h> |
29 | #include <linux/io.h> |
30 | #include <linux/kernel.h> |
31 | #include <linux/module.h> |
32 | #include <linux/pci.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_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), 0, }, |
50 | { 0, }, /* terminate list */ |
51 | }; |
52 | MODULE_DEVICE_TABLE(pci, pci_tbl); |
53 | |
54 | struct amd_geode_priv { |
55 | struct pci_dev *pcidev; |
56 | void __iomem *membase; |
57 | }; |
58 | |
59 | static int geode_rng_data_read(struct hwrng *rng, u32 *data) |
60 | { |
61 | struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv; |
62 | void __iomem *mem = priv->membase; |
63 | |
64 | *data = readl(addr: mem + GEODE_RNG_DATA_REG); |
65 | |
66 | return 4; |
67 | } |
68 | |
69 | static int geode_rng_data_present(struct hwrng *rng, int wait) |
70 | { |
71 | struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv; |
72 | void __iomem *mem = priv->membase; |
73 | int data, i; |
74 | |
75 | for (i = 0; i < 20; i++) { |
76 | data = !!(readl(addr: mem + GEODE_RNG_STATUS_REG)); |
77 | if (data || !wait) |
78 | break; |
79 | udelay(10); |
80 | } |
81 | return data; |
82 | } |
83 | |
84 | |
85 | static struct hwrng geode_rng = { |
86 | .name = "geode" , |
87 | .data_present = geode_rng_data_present, |
88 | .data_read = geode_rng_data_read, |
89 | }; |
90 | |
91 | |
92 | static int __init geode_rng_init(void) |
93 | { |
94 | int err = -ENODEV; |
95 | struct pci_dev *pdev = NULL; |
96 | const struct pci_device_id *ent; |
97 | void __iomem *mem; |
98 | unsigned long rng_base; |
99 | struct amd_geode_priv *priv; |
100 | |
101 | for_each_pci_dev(pdev) { |
102 | ent = pci_match_id(ids: pci_tbl, dev: pdev); |
103 | if (ent) |
104 | goto found; |
105 | } |
106 | /* Device not found. */ |
107 | return err; |
108 | |
109 | found: |
110 | priv = kzalloc(size: sizeof(*priv), GFP_KERNEL); |
111 | if (!priv) { |
112 | err = -ENOMEM; |
113 | goto put_dev; |
114 | } |
115 | |
116 | rng_base = pci_resource_start(pdev, 0); |
117 | if (rng_base == 0) |
118 | goto free_priv; |
119 | err = -ENOMEM; |
120 | mem = ioremap(offset: rng_base, size: 0x58); |
121 | if (!mem) |
122 | goto free_priv; |
123 | |
124 | geode_rng.priv = (unsigned long)priv; |
125 | priv->membase = mem; |
126 | priv->pcidev = pdev; |
127 | |
128 | pr_info("AMD Geode RNG detected\n" ); |
129 | err = hwrng_register(rng: &geode_rng); |
130 | if (err) { |
131 | pr_err(PFX "RNG registering failed (%d)\n" , |
132 | err); |
133 | goto err_unmap; |
134 | } |
135 | return err; |
136 | |
137 | err_unmap: |
138 | iounmap(addr: mem); |
139 | free_priv: |
140 | kfree(objp: priv); |
141 | put_dev: |
142 | pci_dev_put(dev: pdev); |
143 | return err; |
144 | } |
145 | |
146 | static void __exit geode_rng_exit(void) |
147 | { |
148 | struct amd_geode_priv *priv; |
149 | |
150 | priv = (struct amd_geode_priv *)geode_rng.priv; |
151 | hwrng_unregister(rng: &geode_rng); |
152 | iounmap(addr: priv->membase); |
153 | pci_dev_put(dev: priv->pcidev); |
154 | kfree(objp: priv); |
155 | } |
156 | |
157 | module_init(geode_rng_init); |
158 | module_exit(geode_rng_exit); |
159 | |
160 | MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs" ); |
161 | MODULE_LICENSE("GPL" ); |
162 | |