1 /* 2 * RNG driver for AMD 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 <alan@redhat.com> 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/module.h> 28 #include <linux/kernel.h> 29 #include <linux/pci.h> 30 #include <linux/hw_random.h> 31 #include <asm/io.h> 32 33 34 #define PFX KBUILD_MODNAME ": " 35 36 37 /* 38 * Data for PCI driver interface 39 * 40 * This data only exists for exporting the supported 41 * PCI ids via MODULE_DEVICE_TABLE. We do not actually 42 * register a pci_driver, because someone else might one day 43 * want to register another driver on the same PCI id. 44 */ 45 static const struct pci_device_id pci_tbl[] = { 46 { 0x1022, 0x7443, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, }, 47 { 0x1022, 0x746b, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, }, 48 { 0, }, /* terminate list */ 49 }; 50 MODULE_DEVICE_TABLE(pci, pci_tbl); 51 52 static struct pci_dev *amd_pdev; 53 54 55 static int amd_rng_data_present(struct hwrng *rng) 56 { 57 u32 pmbase = (u32)rng->priv; 58 59 return !!(inl(pmbase + 0xF4) & 1); 60 } 61 62 static int amd_rng_data_read(struct hwrng *rng, u32 *data) 63 { 64 u32 pmbase = (u32)rng->priv; 65 66 *data = inl(pmbase + 0xF0); 67 68 return 4; 69 } 70 71 static int amd_rng_init(struct hwrng *rng) 72 { 73 u8 rnen; 74 75 pci_read_config_byte(amd_pdev, 0x40, &rnen); 76 rnen |= (1 << 7); /* RNG on */ 77 pci_write_config_byte(amd_pdev, 0x40, rnen); 78 79 pci_read_config_byte(amd_pdev, 0x41, &rnen); 80 rnen |= (1 << 7); /* PMIO enable */ 81 pci_write_config_byte(amd_pdev, 0x41, rnen); 82 83 return 0; 84 } 85 86 static void amd_rng_cleanup(struct hwrng *rng) 87 { 88 u8 rnen; 89 90 pci_read_config_byte(amd_pdev, 0x40, &rnen); 91 rnen &= ~(1 << 7); /* RNG off */ 92 pci_write_config_byte(amd_pdev, 0x40, rnen); 93 } 94 95 96 static struct hwrng amd_rng = { 97 .name = "amd", 98 .init = amd_rng_init, 99 .cleanup = amd_rng_cleanup, 100 .data_present = amd_rng_data_present, 101 .data_read = amd_rng_data_read, 102 }; 103 104 105 static int __init mod_init(void) 106 { 107 int err = -ENODEV; 108 struct pci_dev *pdev = NULL; 109 const struct pci_device_id *ent; 110 u32 pmbase; 111 112 for_each_pci_dev(pdev) { 113 ent = pci_match_id(pci_tbl, pdev); 114 if (ent) 115 goto found; 116 } 117 /* Device not found. */ 118 goto out; 119 120 found: 121 err = pci_read_config_dword(pdev, 0x58, &pmbase); 122 if (err) 123 goto out; 124 err = -EIO; 125 pmbase &= 0x0000FF00; 126 if (pmbase == 0) 127 goto out; 128 amd_rng.priv = (unsigned long)pmbase; 129 amd_pdev = pdev; 130 131 printk(KERN_INFO "AMD768 RNG detected\n"); 132 err = hwrng_register(&amd_rng); 133 if (err) { 134 printk(KERN_ERR PFX "RNG registering failed (%d)\n", 135 err); 136 goto out; 137 } 138 out: 139 return err; 140 } 141 142 static void __exit mod_exit(void) 143 { 144 hwrng_unregister(&amd_rng); 145 } 146 147 module_init(mod_init); 148 module_exit(mod_exit); 149 150 MODULE_AUTHOR("The Linux Kernel team"); 151 MODULE_DESCRIPTION("H/W RNG driver for AMD chipsets"); 152 MODULE_LICENSE("GPL"); 153