170 lines
3.6 KiB
C
170 lines
3.6 KiB
C
/*
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* RNG driver for AMD 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/module.h>
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#include <linux/kernel.h>
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#include <linux/pci.h>
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#include <linux/hw_random.h>
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#include <linux/delay.h>
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#include <asm/io.h>
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#define PFX KBUILD_MODNAME ": "
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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, 0x7443), 0, },
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{ PCI_VDEVICE(AMD, 0x746b), 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 struct pci_dev *amd_pdev;
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static int amd_rng_data_present(struct hwrng *rng, int wait)
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{
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u32 pmbase = (u32)rng->priv;
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int data, i;
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for (i = 0; i < 20; i++) {
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data = !!(inl(pmbase + 0xF4) & 1);
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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 int amd_rng_data_read(struct hwrng *rng, u32 *data)
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{
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u32 pmbase = (u32)rng->priv;
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*data = inl(pmbase + 0xF0);
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return 4;
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}
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static int amd_rng_init(struct hwrng *rng)
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{
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u8 rnen;
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pci_read_config_byte(amd_pdev, 0x40, &rnen);
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rnen |= (1 << 7); /* RNG on */
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pci_write_config_byte(amd_pdev, 0x40, rnen);
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pci_read_config_byte(amd_pdev, 0x41, &rnen);
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rnen |= (1 << 7); /* PMIO enable */
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pci_write_config_byte(amd_pdev, 0x41, rnen);
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return 0;
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}
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static void amd_rng_cleanup(struct hwrng *rng)
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{
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u8 rnen;
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pci_read_config_byte(amd_pdev, 0x40, &rnen);
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rnen &= ~(1 << 7); /* RNG off */
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pci_write_config_byte(amd_pdev, 0x40, rnen);
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}
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static struct hwrng amd_rng = {
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.name = "amd",
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.init = amd_rng_init,
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.cleanup = amd_rng_cleanup,
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.data_present = amd_rng_data_present,
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.data_read = amd_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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u32 pmbase;
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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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err = pci_read_config_dword(pdev, 0x58, &pmbase);
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if (err)
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goto out;
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err = -EIO;
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pmbase &= 0x0000FF00;
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if (pmbase == 0)
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goto out;
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if (!request_region(pmbase + 0xF0, 8, "AMD HWRNG")) {
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dev_err(&pdev->dev, "AMD HWRNG region 0x%x already in use!\n",
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pmbase + 0xF0);
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err = -EBUSY;
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goto out;
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}
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amd_rng.priv = (unsigned long)pmbase;
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amd_pdev = pdev;
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pr_info("AMD768 RNG detected\n");
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err = hwrng_register(&amd_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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release_region(pmbase + 0xF0, 8);
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goto out;
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}
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out:
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return err;
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}
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static void __exit mod_exit(void)
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{
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u32 pmbase = (unsigned long)amd_rng.priv;
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release_region(pmbase + 0xF0, 8);
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hwrng_unregister(&amd_rng);
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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_AUTHOR("The Linux Kernel team");
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MODULE_DESCRIPTION("H/W RNG driver for AMD chipsets");
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MODULE_LICENSE("GPL");
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