2 * RNG driver for AMD RNGs
4 * Copyright 2005 (c) MontaVista Software, Inc.
6 * with the majority of the code coming from:
8 * Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
9 * (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
13 * Hardware driver for the AMD 768 Random Number Generator (RNG)
14 * (c) Copyright 2001 Red Hat Inc
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>
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.
27 #include <linux/module.h>
28 #include <linux/kernel.h>
29 #include <linux/pci.h>
30 #include <linux/hw_random.h>
31 #include <linux/delay.h>
35 #define PFX KBUILD_MODNAME ": "
39 * Data for PCI driver interface
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.
46 static const struct pci_device_id pci_tbl
[] = {
47 { PCI_VDEVICE(AMD
, 0x7443), 0, },
48 { PCI_VDEVICE(AMD
, 0x746b), 0, },
49 { 0, }, /* terminate list */
51 MODULE_DEVICE_TABLE(pci
, pci_tbl
);
53 static struct pci_dev
*amd_pdev
;
56 static int amd_rng_data_present(struct hwrng
*rng
, int wait
)
58 u32 pmbase
= (u32
)rng
->priv
;
61 for (i
= 0; i
< 20; i
++) {
62 data
= !!(inl(pmbase
+ 0xF4) & 1);
70 static int amd_rng_data_read(struct hwrng
*rng
, u32
*data
)
72 u32 pmbase
= (u32
)rng
->priv
;
74 *data
= inl(pmbase
+ 0xF0);
79 static int amd_rng_init(struct hwrng
*rng
)
83 pci_read_config_byte(amd_pdev
, 0x40, &rnen
);
84 rnen
|= (1 << 7); /* RNG on */
85 pci_write_config_byte(amd_pdev
, 0x40, rnen
);
87 pci_read_config_byte(amd_pdev
, 0x41, &rnen
);
88 rnen
|= (1 << 7); /* PMIO enable */
89 pci_write_config_byte(amd_pdev
, 0x41, rnen
);
94 static void amd_rng_cleanup(struct hwrng
*rng
)
98 pci_read_config_byte(amd_pdev
, 0x40, &rnen
);
99 rnen
&= ~(1 << 7); /* RNG off */
100 pci_write_config_byte(amd_pdev
, 0x40, rnen
);
104 static struct hwrng amd_rng
= {
106 .init
= amd_rng_init
,
107 .cleanup
= amd_rng_cleanup
,
108 .data_present
= amd_rng_data_present
,
109 .data_read
= amd_rng_data_read
,
113 static int __init
mod_init(void)
116 struct pci_dev
*pdev
= NULL
;
117 const struct pci_device_id
*ent
;
120 for_each_pci_dev(pdev
) {
121 ent
= pci_match_id(pci_tbl
, pdev
);
125 /* Device not found. */
129 err
= pci_read_config_dword(pdev
, 0x58, &pmbase
);
133 pmbase
&= 0x0000FF00;
136 amd_rng
.priv
= (unsigned long)pmbase
;
139 printk(KERN_INFO
"AMD768 RNG detected\n");
140 err
= hwrng_register(&amd_rng
);
142 printk(KERN_ERR PFX
"RNG registering failed (%d)\n",
150 static void __exit
mod_exit(void)
152 hwrng_unregister(&amd_rng
);
155 module_init(mod_init
);
156 module_exit(mod_exit
);
158 MODULE_AUTHOR("The Linux Kernel team");
159 MODULE_DESCRIPTION("H/W RNG driver for AMD chipsets");
160 MODULE_LICENSE("GPL");
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