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>
34 #define PFX KBUILD_MODNAME ": "
37 * Data for PCI driver interface
39 * This data only exists for exporting the supported
40 * PCI ids via MODULE_DEVICE_TABLE. We do not actually
41 * register a pci_driver, because someone else might one day
42 * want to register another driver on the same PCI id.
44 static const struct pci_device_id pci_tbl[] = {
45 { PCI_VDEVICE(AMD, 0x7443), 0, },
46 { PCI_VDEVICE(AMD, 0x746b), 0, },
47 { 0, }, /* terminate list */
49 MODULE_DEVICE_TABLE(pci, pci_tbl);
51 static struct pci_dev *amd_pdev;
53 static int amd_rng_data_present(struct hwrng *rng, int wait)
55 u32 pmbase = (u32)rng->priv;
58 for (i = 0; i < 20; i++) {
59 data = !!(inl(pmbase + 0xF4) & 1);
67 static int amd_rng_data_read(struct hwrng *rng, u32 *data)
69 u32 pmbase = (u32)rng->priv;
71 *data = inl(pmbase + 0xF0);
76 static int amd_rng_init(struct hwrng *rng)
80 pci_read_config_byte(amd_pdev, 0x40, &rnen);
81 rnen |= BIT(7); /* RNG on */
82 pci_write_config_byte(amd_pdev, 0x40, rnen);
84 pci_read_config_byte(amd_pdev, 0x41, &rnen);
85 rnen |= BIT(7); /* PMIO enable */
86 pci_write_config_byte(amd_pdev, 0x41, rnen);
91 static void amd_rng_cleanup(struct hwrng *rng)
95 pci_read_config_byte(amd_pdev, 0x40, &rnen);
96 rnen &= ~BIT(7); /* RNG off */
97 pci_write_config_byte(amd_pdev, 0x40, rnen);
100 static struct hwrng amd_rng = {
102 .init = amd_rng_init,
103 .cleanup = amd_rng_cleanup,
104 .data_present = amd_rng_data_present,
105 .data_read = amd_rng_data_read,
108 static int __init mod_init(void)
111 struct pci_dev *pdev = NULL;
112 const struct pci_device_id *ent;
115 for_each_pci_dev(pdev) {
116 ent = pci_match_id(pci_tbl, pdev);
120 /* Device not found. */
124 err = pci_read_config_dword(pdev, 0x58, &pmbase);
128 pmbase &= 0x0000FF00;
131 if (!request_region(pmbase + 0xF0, 8, "AMD HWRNG")) {
132 dev_err(&pdev->dev, "AMD HWRNG region 0x%x already in use!\n",
137 amd_rng.priv = (unsigned long)pmbase;
140 pr_info("AMD768 RNG detected\n");
141 err = hwrng_register(&amd_rng);
143 pr_err(PFX "RNG registering failed (%d)\n",
145 release_region(pmbase + 0xF0, 8);
152 static void __exit mod_exit(void)
154 u32 pmbase = (unsigned long)amd_rng.priv;
156 release_region(pmbase + 0xF0, 8);
157 hwrng_unregister(&amd_rng);
160 module_init(mod_init);
161 module_exit(mod_exit);
163 MODULE_AUTHOR("The Linux Kernel team");
164 MODULE_DESCRIPTION("H/W RNG driver for AMD chipsets");
165 MODULE_LICENSE("GPL");