1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * RNG driver for AMD Geode RNGs
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * Copyright 2005 (c) MontaVista Software, Inc.
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * with the majority of the code coming from:
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
9*4882a593Smuzhiyun * (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
10*4882a593Smuzhiyun *
11*4882a593Smuzhiyun * derived from
12*4882a593Smuzhiyun *
13*4882a593Smuzhiyun * Hardware driver for the AMD 768 Random Number Generator (RNG)
14*4882a593Smuzhiyun * (c) Copyright 2001 Red Hat Inc
15*4882a593Smuzhiyun *
16*4882a593Smuzhiyun * derived from
17*4882a593Smuzhiyun *
18*4882a593Smuzhiyun * Hardware driver for Intel i810 Random Number Generator (RNG)
19*4882a593Smuzhiyun * Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
20*4882a593Smuzhiyun * Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
21*4882a593Smuzhiyun *
22*4882a593Smuzhiyun * This file is licensed under the terms of the GNU General Public
23*4882a593Smuzhiyun * License version 2. This program is licensed "as is" without any
24*4882a593Smuzhiyun * warranty of any kind, whether express or implied.
25*4882a593Smuzhiyun */
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun #include <linux/delay.h>
28*4882a593Smuzhiyun #include <linux/hw_random.h>
29*4882a593Smuzhiyun #include <linux/io.h>
30*4882a593Smuzhiyun #include <linux/kernel.h>
31*4882a593Smuzhiyun #include <linux/module.h>
32*4882a593Smuzhiyun #include <linux/pci.h>
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun #define PFX KBUILD_MODNAME ": "
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun #define GEODE_RNG_DATA_REG 0x50
38*4882a593Smuzhiyun #define GEODE_RNG_STATUS_REG 0x54
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun /*
41*4882a593Smuzhiyun * Data for PCI driver interface
42*4882a593Smuzhiyun *
43*4882a593Smuzhiyun * This data only exists for exporting the supported
44*4882a593Smuzhiyun * PCI ids via MODULE_DEVICE_TABLE. We do not actually
45*4882a593Smuzhiyun * register a pci_driver, because someone else might one day
46*4882a593Smuzhiyun * want to register another driver on the same PCI id.
47*4882a593Smuzhiyun */
48*4882a593Smuzhiyun static const struct pci_device_id pci_tbl[] = {
49*4882a593Smuzhiyun { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), 0, },
50*4882a593Smuzhiyun { 0, }, /* terminate list */
51*4882a593Smuzhiyun };
52*4882a593Smuzhiyun MODULE_DEVICE_TABLE(pci, pci_tbl);
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun
geode_rng_data_read(struct hwrng * rng,u32 * data)55*4882a593Smuzhiyun static int geode_rng_data_read(struct hwrng *rng, u32 *data)
56*4882a593Smuzhiyun {
57*4882a593Smuzhiyun void __iomem *mem = (void __iomem *)rng->priv;
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun *data = readl(mem + GEODE_RNG_DATA_REG);
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun return 4;
62*4882a593Smuzhiyun }
63*4882a593Smuzhiyun
geode_rng_data_present(struct hwrng * rng,int wait)64*4882a593Smuzhiyun static int geode_rng_data_present(struct hwrng *rng, int wait)
65*4882a593Smuzhiyun {
66*4882a593Smuzhiyun void __iomem *mem = (void __iomem *)rng->priv;
67*4882a593Smuzhiyun int data, i;
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun for (i = 0; i < 20; i++) {
70*4882a593Smuzhiyun data = !!(readl(mem + GEODE_RNG_STATUS_REG));
71*4882a593Smuzhiyun if (data || !wait)
72*4882a593Smuzhiyun break;
73*4882a593Smuzhiyun udelay(10);
74*4882a593Smuzhiyun }
75*4882a593Smuzhiyun return data;
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun static struct hwrng geode_rng = {
80*4882a593Smuzhiyun .name = "geode",
81*4882a593Smuzhiyun .data_present = geode_rng_data_present,
82*4882a593Smuzhiyun .data_read = geode_rng_data_read,
83*4882a593Smuzhiyun };
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun
mod_init(void)86*4882a593Smuzhiyun static int __init mod_init(void)
87*4882a593Smuzhiyun {
88*4882a593Smuzhiyun int err = -ENODEV;
89*4882a593Smuzhiyun struct pci_dev *pdev = NULL;
90*4882a593Smuzhiyun const struct pci_device_id *ent;
91*4882a593Smuzhiyun void __iomem *mem;
92*4882a593Smuzhiyun unsigned long rng_base;
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun for_each_pci_dev(pdev) {
95*4882a593Smuzhiyun ent = pci_match_id(pci_tbl, pdev);
96*4882a593Smuzhiyun if (ent)
97*4882a593Smuzhiyun goto found;
98*4882a593Smuzhiyun }
99*4882a593Smuzhiyun /* Device not found. */
100*4882a593Smuzhiyun goto out;
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun found:
103*4882a593Smuzhiyun rng_base = pci_resource_start(pdev, 0);
104*4882a593Smuzhiyun if (rng_base == 0)
105*4882a593Smuzhiyun goto out;
106*4882a593Smuzhiyun err = -ENOMEM;
107*4882a593Smuzhiyun mem = ioremap(rng_base, 0x58);
108*4882a593Smuzhiyun if (!mem)
109*4882a593Smuzhiyun goto out;
110*4882a593Smuzhiyun geode_rng.priv = (unsigned long)mem;
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun pr_info("AMD Geode RNG detected\n");
113*4882a593Smuzhiyun err = hwrng_register(&geode_rng);
114*4882a593Smuzhiyun if (err) {
115*4882a593Smuzhiyun pr_err(PFX "RNG registering failed (%d)\n",
116*4882a593Smuzhiyun err);
117*4882a593Smuzhiyun goto err_unmap;
118*4882a593Smuzhiyun }
119*4882a593Smuzhiyun out:
120*4882a593Smuzhiyun return err;
121*4882a593Smuzhiyun
122*4882a593Smuzhiyun err_unmap:
123*4882a593Smuzhiyun iounmap(mem);
124*4882a593Smuzhiyun goto out;
125*4882a593Smuzhiyun }
126*4882a593Smuzhiyun
mod_exit(void)127*4882a593Smuzhiyun static void __exit mod_exit(void)
128*4882a593Smuzhiyun {
129*4882a593Smuzhiyun void __iomem *mem = (void __iomem *)geode_rng.priv;
130*4882a593Smuzhiyun
131*4882a593Smuzhiyun hwrng_unregister(&geode_rng);
132*4882a593Smuzhiyun iounmap(mem);
133*4882a593Smuzhiyun }
134*4882a593Smuzhiyun
135*4882a593Smuzhiyun module_init(mod_init);
136*4882a593Smuzhiyun module_exit(mod_exit);
137*4882a593Smuzhiyun
138*4882a593Smuzhiyun MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs");
139*4882a593Smuzhiyun MODULE_LICENSE("GPL");
140