2 * RNG driver for AMD Geode 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 ": "
37 #define GEODE_RNG_DATA_REG 0x50
38 #define GEODE_RNG_STATUS_REG 0x54
41 * Data for PCI driver interface
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.
48 static const struct pci_device_id pci_tbl
[] = {
49 { PCI_VDEVICE(AMD
, PCI_DEVICE_ID_AMD_LX_AES
), 0, },
50 { 0, }, /* terminate list */
52 MODULE_DEVICE_TABLE(pci
, pci_tbl
);
55 static int geode_rng_data_read(struct hwrng
*rng
, u32
*data
)
57 void __iomem
*mem
= (void __iomem
*)rng
->priv
;
59 *data
= readl(mem
+ GEODE_RNG_DATA_REG
);
64 static int geode_rng_data_present(struct hwrng
*rng
, int wait
)
66 void __iomem
*mem
= (void __iomem
*)rng
->priv
;
69 for (i
= 0; i
< 20; i
++) {
70 data
= !!(readl(mem
+ GEODE_RNG_STATUS_REG
));
79 static struct hwrng geode_rng
= {
81 .data_present
= geode_rng_data_present
,
82 .data_read
= geode_rng_data_read
,
86 static int __init
mod_init(void)
89 struct pci_dev
*pdev
= NULL
;
90 const struct pci_device_id
*ent
;
92 unsigned long rng_base
;
94 for_each_pci_dev(pdev
) {
95 ent
= pci_match_id(pci_tbl
, pdev
);
99 /* Device not found. */
103 rng_base
= pci_resource_start(pdev
, 0);
107 mem
= ioremap(rng_base
, 0x58);
110 geode_rng
.priv
= (unsigned long)mem
;
112 pr_info("AMD Geode RNG detected\n");
113 err
= hwrng_register(&geode_rng
);
115 pr_err(PFX
"RNG registering failed (%d)\n",
127 static void __exit
mod_exit(void)
129 void __iomem
*mem
= (void __iomem
*)geode_rng
.priv
;
131 hwrng_unregister(&geode_rng
);
135 module_init(mod_init
);
136 module_exit(mod_exit
);
138 MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs");
139 MODULE_LICENSE("GPL");
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