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1/*2 * RNG driver for AMD Geode RNGs3 *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 from12 *13 * Hardware driver for the AMD 768 Random Number Generator (RNG)14 * (c) Copyright 2001 Red Hat Inc15 *16 * derived from17 *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 Public23 * License version 2. This program is licensed "as is" without any24 * warranty of any kind, whether express or implied.25 */26 27#include <linux/delay.h>28#include <linux/hw_random.h>29#include <linux/io.h>30#include <linux/kernel.h>31#include <linux/module.h>32#include <linux/pci.h>33 34 35#define PFX KBUILD_MODNAME ": "36 37#define GEODE_RNG_DATA_REG 0x5038#define GEODE_RNG_STATUS_REG 0x5439 40/*41 * Data for PCI driver interface42 *43 * This data only exists for exporting the supported44 * PCI ids via MODULE_DEVICE_TABLE. We do not actually45 * register a pci_driver, because someone else might one day46 * want to register another driver on the same PCI id.47 */48static const struct pci_device_id pci_tbl[] = {49 { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), 0, },50 { 0, }, /* terminate list */51};52MODULE_DEVICE_TABLE(pci, pci_tbl);53 54struct amd_geode_priv {55 struct pci_dev *pcidev;56 void __iomem *membase;57};58 59static int geode_rng_data_read(struct hwrng *rng, u32 *data)60{61 struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv;62 void __iomem *mem = priv->membase;63 64 *data = readl(mem + GEODE_RNG_DATA_REG);65 66 return 4;67}68 69static int geode_rng_data_present(struct hwrng *rng, int wait)70{71 struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv;72 void __iomem *mem = priv->membase;73 int data, i;74 75 for (i = 0; i < 20; i++) {76 data = !!(readl(mem + GEODE_RNG_STATUS_REG));77 if (data || !wait)78 break;79 udelay(10);80 }81 return data;82}83 84 85static struct hwrng geode_rng = {86 .name = "geode",87 .data_present = geode_rng_data_present,88 .data_read = geode_rng_data_read,89};90 91 92static int __init geode_rng_init(void)93{94 int err = -ENODEV;95 struct pci_dev *pdev = NULL;96 const struct pci_device_id *ent;97 void __iomem *mem;98 unsigned long rng_base;99 struct amd_geode_priv *priv;100 101 for_each_pci_dev(pdev) {102 ent = pci_match_id(pci_tbl, pdev);103 if (ent)104 goto found;105 }106 /* Device not found. */107 return err;108 109found:110 priv = kzalloc(sizeof(*priv), GFP_KERNEL);111 if (!priv) {112 err = -ENOMEM;113 goto put_dev;114 }115 116 rng_base = pci_resource_start(pdev, 0);117 if (rng_base == 0)118 goto free_priv;119 err = -ENOMEM;120 mem = ioremap(rng_base, 0x58);121 if (!mem)122 goto free_priv;123 124 geode_rng.priv = (unsigned long)priv;125 priv->membase = mem;126 priv->pcidev = pdev;127 128 pr_info("AMD Geode RNG detected\n");129 err = hwrng_register(&geode_rng);130 if (err) {131 pr_err(PFX "RNG registering failed (%d)\n",132 err);133 goto err_unmap;134 }135 return err;136 137err_unmap:138 iounmap(mem);139free_priv:140 kfree(priv);141put_dev:142 pci_dev_put(pdev);143 return err;144}145 146static void __exit geode_rng_exit(void)147{148 struct amd_geode_priv *priv;149 150 priv = (struct amd_geode_priv *)geode_rng.priv;151 hwrng_unregister(&geode_rng);152 iounmap(priv->membase);153 pci_dev_put(priv->pcidev);154 kfree(priv);155}156 157module_init(geode_rng_init);158module_exit(geode_rng_exit);159 160MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs");161MODULE_LICENSE("GPL");162