/* * RNG driver for AMD RNGs * * Copyright 2005 (c) MontaVista Software, Inc. * * with the majority of the code coming from: * * Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG) * (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com> * * derived from * * Hardware driver for the AMD 768 Random Number Generator (RNG) * (c) Copyright 2001 Red Hat Inc * * derived from * * Hardware driver for Intel i810 Random Number Generator (RNG) * Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com> * Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com> * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/pci.h> #include <linux/hw_random.h> #include <linux/delay.h> #include <asm/io.h> #define PFX KBUILD_MODNAME ": " /* * Data for PCI driver interface * * This data only exists for exporting the supported * PCI ids via MODULE_DEVICE_TABLE. We do not actually * register a pci_driver, because someone else might one day * want to register another driver on the same PCI id. */ static const struct pci_device_id pci_tbl[] = { { PCI_VDEVICE(AMD, 0x7443), 0, }, { PCI_VDEVICE(AMD, 0x746b), 0, }, { 0, }, /* terminate list */ }; MODULE_DEVICE_TABLE(pci, pci_tbl); static struct pci_dev *amd_pdev; static int amd_rng_data_present(struct hwrng *rng, int wait) { u32 pmbase = (u32)rng->priv; int data, i; for (i = 0; i < 20; i++) { data = !!(inl(pmbase + 0xF4) & 1); if (data || !wait) break; udelay(10); } return data; } static int amd_rng_data_read(struct hwrng *rng, u32 *data) { u32 pmbase = (u32)rng->priv; *data = inl(pmbase + 0xF0); return 4; } static int amd_rng_init(struct hwrng *rng) { u8 rnen; pci_read_config_byte(amd_pdev, 0x40, &rnen); rnen |= (1 << 7); /* RNG on */ pci_write_config_byte(amd_pdev, 0x40, rnen); pci_read_config_byte(amd_pdev, 0x41, &rnen); rnen |= (1 << 7); /* PMIO enable */ pci_write_config_byte(amd_pdev, 0x41, rnen); return 0; } static void amd_rng_cleanup(struct hwrng *rng) { u8 rnen; pci_read_config_byte(amd_pdev, 0x40, &rnen); rnen &= ~(1 << 7); /* RNG off */ pci_write_config_byte(amd_pdev, 0x40, rnen); } static struct hwrng amd_rng = { .name = "amd", .init = amd_rng_init, .cleanup = amd_rng_cleanup, .data_present = amd_rng_data_present, .data_read = amd_rng_data_read, }; static int __init mod_init(void) { int err = -ENODEV; struct pci_dev *pdev = NULL; const struct pci_device_id *ent; u32 pmbase; for_each_pci_dev(pdev) { ent = pci_match_id(pci_tbl, pdev); if (ent) goto found; } /* Device not found. */ goto out; found: err = pci_read_config_dword(pdev, 0x58, &pmbase); if (err) goto out; err = -EIO; pmbase &= 0x0000FF00; if (pmbase == 0) goto out; amd_rng.priv = (unsigned long)pmbase; amd_pdev = pdev; printk(KERN_INFO "AMD768 RNG detected\n"); err = hwrng_register(&amd_rng); if (err) { printk(KERN_ERR PFX "RNG registering failed (%d)\n", err); goto out; } out: return err; } static void __exit mod_exit(void) { hwrng_unregister(&amd_rng); } module_init(mod_init); module_exit(mod_exit); MODULE_AUTHOR("The Linux Kernel team"); MODULE_DESCRIPTION("H/W RNG driver for AMD chipsets"); MODULE_LICENSE("GPL");