diff options
Diffstat (limited to 'drivers/char/hw_random/intel-rng.c')
| -rw-r--r-- | drivers/char/hw_random/intel-rng.c | 418 |
1 files changed, 418 insertions, 0 deletions
diff --git a/drivers/char/hw_random/intel-rng.c b/drivers/char/hw_random/intel-rng.c new file mode 100644 index 000000000..290c88026 --- /dev/null +++ b/drivers/char/hw_random/intel-rng.c @@ -0,0 +1,418 @@ +/* + * RNG driver for Intel 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/hw_random.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/stop_machine.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <asm/io.h> + + +#define PFX KBUILD_MODNAME ": " + +/* + * RNG registers + */ +#define INTEL_RNG_HW_STATUS 0 +#define INTEL_RNG_PRESENT 0x40 +#define INTEL_RNG_ENABLED 0x01 +#define INTEL_RNG_STATUS 1 +#define INTEL_RNG_DATA_PRESENT 0x01 +#define INTEL_RNG_DATA 2 + +/* + * Magic address at which Intel PCI bridges locate the RNG + */ +#define INTEL_RNG_ADDR 0xFFBC015F +#define INTEL_RNG_ADDR_LEN 3 + +/* + * LPC bridge PCI config space registers + */ +#define FWH_DEC_EN1_REG_OLD 0xe3 +#define FWH_DEC_EN1_REG_NEW 0xd9 /* high byte of 16-bit register */ +#define FWH_F8_EN_MASK 0x80 + +#define BIOS_CNTL_REG_OLD 0x4e +#define BIOS_CNTL_REG_NEW 0xdc +#define BIOS_CNTL_WRITE_ENABLE_MASK 0x01 +#define BIOS_CNTL_LOCK_ENABLE_MASK 0x02 + +/* + * Magic address at which Intel Firmware Hubs get accessed + */ +#define INTEL_FWH_ADDR 0xffff0000 +#define INTEL_FWH_ADDR_LEN 2 + +/* + * Intel Firmware Hub command codes (write to any address inside the device) + */ +#define INTEL_FWH_RESET_CMD 0xff /* aka READ_ARRAY */ +#define INTEL_FWH_READ_ID_CMD 0x90 + +/* + * Intel Firmware Hub Read ID command result addresses + */ +#define INTEL_FWH_MANUFACTURER_CODE_ADDRESS 0x000000 +#define INTEL_FWH_DEVICE_CODE_ADDRESS 0x000001 + +/* + * Intel Firmware Hub Read ID command result values + */ +#define INTEL_FWH_MANUFACTURER_CODE 0x89 +#define INTEL_FWH_DEVICE_CODE_8M 0xac +#define INTEL_FWH_DEVICE_CODE_4M 0xad + +/* + * 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[] = { +/* AA + { PCI_DEVICE(0x8086, 0x2418) }, */ + { PCI_DEVICE(0x8086, 0x2410) }, /* AA */ +/* AB + { PCI_DEVICE(0x8086, 0x2428) }, */ + { PCI_DEVICE(0x8086, 0x2420) }, /* AB */ +/* ?? + { PCI_DEVICE(0x8086, 0x2430) }, */ +/* BAM, CAM, DBM, FBM, GxM + { PCI_DEVICE(0x8086, 0x2448) }, */ + { PCI_DEVICE(0x8086, 0x244c) }, /* BAM */ + { PCI_DEVICE(0x8086, 0x248c) }, /* CAM */ + { PCI_DEVICE(0x8086, 0x24cc) }, /* DBM */ + { PCI_DEVICE(0x8086, 0x2641) }, /* FBM */ + { PCI_DEVICE(0x8086, 0x27b9) }, /* GxM */ + { PCI_DEVICE(0x8086, 0x27bd) }, /* GxM DH */ +/* BA, CA, DB, Ex, 6300, Fx, 631x/632x, Gx + { PCI_DEVICE(0x8086, 0x244e) }, */ + { PCI_DEVICE(0x8086, 0x2440) }, /* BA */ + { PCI_DEVICE(0x8086, 0x2480) }, /* CA */ + { PCI_DEVICE(0x8086, 0x24c0) }, /* DB */ + { PCI_DEVICE(0x8086, 0x24d0) }, /* Ex */ + { PCI_DEVICE(0x8086, 0x25a1) }, /* 6300 */ + { PCI_DEVICE(0x8086, 0x2640) }, /* Fx */ + { PCI_DEVICE(0x8086, 0x2670) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x2671) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x2672) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x2673) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x2674) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x2675) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x2676) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x2677) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x2678) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x2679) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x267a) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x267b) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x267c) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x267d) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x267e) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x267f) }, /* 631x/632x */ + { PCI_DEVICE(0x8086, 0x27b8) }, /* Gx */ +/* E + { PCI_DEVICE(0x8086, 0x245e) }, */ + { PCI_DEVICE(0x8086, 0x2450) }, /* E */ + { 0, }, /* terminate list */ +}; +MODULE_DEVICE_TABLE(pci, pci_tbl); + +static __initdata int no_fwh_detect; +module_param(no_fwh_detect, int, 0); +MODULE_PARM_DESC(no_fwh_detect, "Skip FWH detection:\n" + " positive value - skip if FWH space locked read-only\n" + " negative value - skip always"); + +static inline u8 hwstatus_get(void __iomem *mem) +{ + return readb(mem + INTEL_RNG_HW_STATUS); +} + +static inline u8 hwstatus_set(void __iomem *mem, + u8 hw_status) +{ + writeb(hw_status, mem + INTEL_RNG_HW_STATUS); + return hwstatus_get(mem); +} + +static int intel_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 = !!(readb(mem + INTEL_RNG_STATUS) & + INTEL_RNG_DATA_PRESENT); + if (data || !wait) + break; + udelay(10); + } + return data; +} + +static int intel_rng_data_read(struct hwrng *rng, u32 *data) +{ + void __iomem *mem = (void __iomem *)rng->priv; + + *data = readb(mem + INTEL_RNG_DATA); + + return 1; +} + +static int intel_rng_init(struct hwrng *rng) +{ + void __iomem *mem = (void __iomem *)rng->priv; + u8 hw_status; + int err = -EIO; + + hw_status = hwstatus_get(mem); + /* turn RNG h/w on, if it's off */ + if ((hw_status & INTEL_RNG_ENABLED) == 0) + hw_status = hwstatus_set(mem, hw_status | INTEL_RNG_ENABLED); + if ((hw_status & INTEL_RNG_ENABLED) == 0) { + pr_err(PFX "cannot enable RNG, aborting\n"); + goto out; + } + err = 0; +out: + return err; +} + +static void intel_rng_cleanup(struct hwrng *rng) +{ + void __iomem *mem = (void __iomem *)rng->priv; + u8 hw_status; + + hw_status = hwstatus_get(mem); + if (hw_status & INTEL_RNG_ENABLED) + hwstatus_set(mem, hw_status & ~INTEL_RNG_ENABLED); + else + pr_warn(PFX "unusual: RNG already disabled\n"); +} + + +static struct hwrng intel_rng = { + .name = "intel", + .init = intel_rng_init, + .cleanup = intel_rng_cleanup, + .data_present = intel_rng_data_present, + .data_read = intel_rng_data_read, +}; + +struct intel_rng_hw { + struct pci_dev *dev; + void __iomem *mem; + u8 bios_cntl_off; + u8 bios_cntl_val; + u8 fwh_dec_en1_off; + u8 fwh_dec_en1_val; +}; + +static int __init intel_rng_hw_init(void *_intel_rng_hw) +{ + struct intel_rng_hw *intel_rng_hw = _intel_rng_hw; + u8 mfc, dvc; + + /* interrupts disabled in stop_machine call */ + + if (!(intel_rng_hw->fwh_dec_en1_val & FWH_F8_EN_MASK)) + pci_write_config_byte(intel_rng_hw->dev, + intel_rng_hw->fwh_dec_en1_off, + intel_rng_hw->fwh_dec_en1_val | + FWH_F8_EN_MASK); + if (!(intel_rng_hw->bios_cntl_val & BIOS_CNTL_WRITE_ENABLE_MASK)) + pci_write_config_byte(intel_rng_hw->dev, + intel_rng_hw->bios_cntl_off, + intel_rng_hw->bios_cntl_val | + BIOS_CNTL_WRITE_ENABLE_MASK); + + writeb(INTEL_FWH_RESET_CMD, intel_rng_hw->mem); + writeb(INTEL_FWH_READ_ID_CMD, intel_rng_hw->mem); + mfc = readb(intel_rng_hw->mem + INTEL_FWH_MANUFACTURER_CODE_ADDRESS); + dvc = readb(intel_rng_hw->mem + INTEL_FWH_DEVICE_CODE_ADDRESS); + writeb(INTEL_FWH_RESET_CMD, intel_rng_hw->mem); + + if (!(intel_rng_hw->bios_cntl_val & + (BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK))) + pci_write_config_byte(intel_rng_hw->dev, + intel_rng_hw->bios_cntl_off, + intel_rng_hw->bios_cntl_val); + if (!(intel_rng_hw->fwh_dec_en1_val & FWH_F8_EN_MASK)) + pci_write_config_byte(intel_rng_hw->dev, + intel_rng_hw->fwh_dec_en1_off, + intel_rng_hw->fwh_dec_en1_val); + + if (mfc != INTEL_FWH_MANUFACTURER_CODE || + (dvc != INTEL_FWH_DEVICE_CODE_8M && + dvc != INTEL_FWH_DEVICE_CODE_4M)) { + pr_notice(PFX "FWH not detected\n"); + return -ENODEV; + } + + return 0; +} + +static int __init intel_init_hw_struct(struct intel_rng_hw *intel_rng_hw, + struct pci_dev *dev) +{ + intel_rng_hw->bios_cntl_val = 0xff; + intel_rng_hw->fwh_dec_en1_val = 0xff; + intel_rng_hw->dev = dev; + + /* Check for Intel 82802 */ + if (dev->device < 0x2640) { + intel_rng_hw->fwh_dec_en1_off = FWH_DEC_EN1_REG_OLD; + intel_rng_hw->bios_cntl_off = BIOS_CNTL_REG_OLD; + } else { + intel_rng_hw->fwh_dec_en1_off = FWH_DEC_EN1_REG_NEW; + intel_rng_hw->bios_cntl_off = BIOS_CNTL_REG_NEW; + } + + pci_read_config_byte(dev, intel_rng_hw->fwh_dec_en1_off, + &intel_rng_hw->fwh_dec_en1_val); + pci_read_config_byte(dev, intel_rng_hw->bios_cntl_off, + &intel_rng_hw->bios_cntl_val); + + if ((intel_rng_hw->bios_cntl_val & + (BIOS_CNTL_LOCK_ENABLE_MASK|BIOS_CNTL_WRITE_ENABLE_MASK)) + == BIOS_CNTL_LOCK_ENABLE_MASK) { + static __initdata /*const*/ char warning[] = +PFX "Firmware space is locked read-only. If you can't or\n" +PFX "don't want to disable this in firmware setup, and if\n" +PFX "you are certain that your system has a functional\n" +PFX "RNG, try using the 'no_fwh_detect' option.\n"; + + if (no_fwh_detect) + return -ENODEV; + pr_warn("%s", warning); + return -EBUSY; + } + + intel_rng_hw->mem = ioremap_nocache(INTEL_FWH_ADDR, INTEL_FWH_ADDR_LEN); + if (intel_rng_hw->mem == NULL) + return -EBUSY; + + return 0; +} + + +static int __init mod_init(void) +{ + int err = -ENODEV; + int i; + struct pci_dev *dev = NULL; + void __iomem *mem = mem; + u8 hw_status; + struct intel_rng_hw *intel_rng_hw; + + for (i = 0; !dev && pci_tbl[i].vendor; ++i) + dev = pci_get_device(pci_tbl[i].vendor, pci_tbl[i].device, + NULL); + + if (!dev) + goto out; /* Device not found. */ + + if (no_fwh_detect < 0) { + pci_dev_put(dev); + goto fwh_done; + } + + intel_rng_hw = kmalloc(sizeof(*intel_rng_hw), GFP_KERNEL); + if (!intel_rng_hw) { + pci_dev_put(dev); + goto out; + } + + err = intel_init_hw_struct(intel_rng_hw, dev); + if (err) { + pci_dev_put(dev); + kfree(intel_rng_hw); + if (err == -ENODEV) + goto fwh_done; + goto out; + } + + /* + * Since the BIOS code/data is going to disappear from its normal + * location with the Read ID command, all activity on the system + * must be stopped until the state is back to normal. + * + * Use stop_machine because IPIs can be blocked by disabling + * interrupts. + */ + err = stop_machine(intel_rng_hw_init, intel_rng_hw, NULL); + pci_dev_put(dev); + iounmap(intel_rng_hw->mem); + kfree(intel_rng_hw); + if (err) + goto out; + +fwh_done: + err = -ENOMEM; + mem = ioremap(INTEL_RNG_ADDR, INTEL_RNG_ADDR_LEN); + if (!mem) + goto out; + intel_rng.priv = (unsigned long)mem; + + /* Check for Random Number Generator */ + err = -ENODEV; + hw_status = hwstatus_get(mem); + if ((hw_status & INTEL_RNG_PRESENT) == 0) { + iounmap(mem); + goto out; + } + + pr_info("Intel 82802 RNG detected\n"); + err = hwrng_register(&intel_rng); + if (err) { + pr_err(PFX "RNG registering failed (%d)\n", + err); + iounmap(mem); + } +out: + return err; + +} + +static void __exit mod_exit(void) +{ + void __iomem *mem = (void __iomem *)intel_rng.priv; + + hwrng_unregister(&intel_rng); + iounmap(mem); +} + +module_init(mod_init); +module_exit(mod_exit); + +MODULE_DESCRIPTION("H/W RNG driver for Intel chipsets"); +MODULE_LICENSE("GPL"); |