diff options
Diffstat (limited to 'drivers/char/hw_random/amd-rng.c')
| -rw-r--r-- | drivers/char/hw_random/amd-rng.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/drivers/char/hw_random/amd-rng.c b/drivers/char/hw_random/amd-rng.c new file mode 100644 index 00000000..c6af0386 --- /dev/null +++ b/drivers/char/hw_random/amd-rng.c @@ -0,0 +1,169 @@ +/* + * 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; + if (!request_region(pmbase + 0xF0, 8, "AMD HWRNG")) { + dev_err(&pdev->dev, "AMD HWRNG region 0x%x already in use!\n", + pmbase + 0xF0); + err = -EBUSY; + 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); + release_region(pmbase + 0xF0, 8); + goto out; + } +out: + return err; +} + +static void __exit mod_exit(void) +{ + u32 pmbase = (unsigned long)amd_rng.priv; + release_region(pmbase + 0xF0, 8); + 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"); |