diff options
Diffstat (limited to 'drivers/char/hw_random/geode-rng.c')
| -rw-r--r-- | drivers/char/hw_random/geode-rng.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/drivers/char/hw_random/geode-rng.c b/drivers/char/hw_random/geode-rng.c new file mode 100644 index 000000000..e1d421a36 --- /dev/null +++ b/drivers/char/hw_random/geode-rng.c @@ -0,0 +1,139 @@ +/* + * RNG driver for AMD Geode 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/delay.h> +#include <linux/hw_random.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/pci.h> + + +#define PFX KBUILD_MODNAME ": " + +#define GEODE_RNG_DATA_REG 0x50 +#define GEODE_RNG_STATUS_REG 0x54 + +/* + * 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, PCI_DEVICE_ID_AMD_LX_AES), 0, }, + { 0, }, /* terminate list */ +}; +MODULE_DEVICE_TABLE(pci, pci_tbl); + + +static int geode_rng_data_read(struct hwrng *rng, u32 *data) +{ + void __iomem *mem = (void __iomem *)rng->priv; + + *data = readl(mem + GEODE_RNG_DATA_REG); + + return 4; +} + +static int geode_rng_data_present(struct hwrng *rng, int wait) +{ + void __iomem *mem = (void __iomem *)rng->priv; + int data, i; + + for (i = 0; i < 20; i++) { + data = !!(readl(mem + GEODE_RNG_STATUS_REG)); + if (data || !wait) + break; + udelay(10); + } + return data; +} + + +static struct hwrng geode_rng = { + .name = "geode", + .data_present = geode_rng_data_present, + .data_read = geode_rng_data_read, +}; + + +static int __init mod_init(void) +{ + int err = -ENODEV; + struct pci_dev *pdev = NULL; + const struct pci_device_id *ent; + void __iomem *mem; + unsigned long rng_base; + + for_each_pci_dev(pdev) { + ent = pci_match_id(pci_tbl, pdev); + if (ent) + goto found; + } + /* Device not found. */ + goto out; + +found: + rng_base = pci_resource_start(pdev, 0); + if (rng_base == 0) + goto out; + err = -ENOMEM; + mem = ioremap(rng_base, 0x58); + if (!mem) + goto out; + geode_rng.priv = (unsigned long)mem; + + pr_info("AMD Geode RNG detected\n"); + err = hwrng_register(&geode_rng); + if (err) { + pr_err(PFX "RNG registering failed (%d)\n", + err); + goto err_unmap; + } +out: + return err; + +err_unmap: + iounmap(mem); + goto out; +} + +static void __exit mod_exit(void) +{ + void __iomem *mem = (void __iomem *)geode_rng.priv; + + hwrng_unregister(&geode_rng); + iounmap(mem); +} + +module_init(mod_init); +module_exit(mod_exit); + +MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs"); +MODULE_LICENSE("GPL"); |