140 lines
3 KiB
C
140 lines
3 KiB
C
/*
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* RNG driver for AMD Geode RNGs
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*
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* Copyright 2005 (c) MontaVista Software, Inc.
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*
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* with the majority of the code coming from:
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*
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* Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
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* (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
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*
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* derived from
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*
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* Hardware driver for the AMD 768 Random Number Generator (RNG)
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* (c) Copyright 2001 Red Hat Inc
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*
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* derived from
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*
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* Hardware driver for Intel i810 Random Number Generator (RNG)
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* Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
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* Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/delay.h>
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#include <linux/hw_random.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#define PFX KBUILD_MODNAME ": "
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#define GEODE_RNG_DATA_REG 0x50
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#define GEODE_RNG_STATUS_REG 0x54
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/*
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* Data for PCI driver interface
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*
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* This data only exists for exporting the supported
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* PCI ids via MODULE_DEVICE_TABLE. We do not actually
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* register a pci_driver, because someone else might one day
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* want to register another driver on the same PCI id.
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*/
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static const struct pci_device_id pci_tbl[] = {
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{ PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), 0, },
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{ 0, }, /* terminate list */
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};
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MODULE_DEVICE_TABLE(pci, pci_tbl);
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static int geode_rng_data_read(struct hwrng *rng, u32 *data)
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{
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void __iomem *mem = (void __iomem *)rng->priv;
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*data = readl(mem + GEODE_RNG_DATA_REG);
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return 4;
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}
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static int geode_rng_data_present(struct hwrng *rng, int wait)
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{
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void __iomem *mem = (void __iomem *)rng->priv;
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int data, i;
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for (i = 0; i < 20; i++) {
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data = !!(readl(mem + GEODE_RNG_STATUS_REG));
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if (data || !wait)
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break;
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udelay(10);
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}
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return data;
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}
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static struct hwrng geode_rng = {
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.name = "geode",
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.data_present = geode_rng_data_present,
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.data_read = geode_rng_data_read,
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};
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static int __init mod_init(void)
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{
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int err = -ENODEV;
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struct pci_dev *pdev = NULL;
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const struct pci_device_id *ent;
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void __iomem *mem;
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unsigned long rng_base;
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for_each_pci_dev(pdev) {
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ent = pci_match_id(pci_tbl, pdev);
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if (ent)
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goto found;
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}
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/* Device not found. */
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goto out;
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found:
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rng_base = pci_resource_start(pdev, 0);
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if (rng_base == 0)
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goto out;
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err = -ENOMEM;
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mem = ioremap(rng_base, 0x58);
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if (!mem)
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goto out;
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geode_rng.priv = (unsigned long)mem;
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pr_info("AMD Geode RNG detected\n");
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err = hwrng_register(&geode_rng);
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if (err) {
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pr_err(PFX "RNG registering failed (%d)\n",
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err);
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goto err_unmap;
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}
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out:
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return err;
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err_unmap:
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iounmap(mem);
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goto out;
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}
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static void __exit mod_exit(void)
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{
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void __iomem *mem = (void __iomem *)geode_rng.priv;
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hwrng_unregister(&geode_rng);
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iounmap(mem);
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}
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module_init(mod_init);
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module_exit(mod_exit);
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MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs");
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MODULE_LICENSE("GPL");
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