--- /dev/null
+/*
+ * 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");
Code Review / kvmfornfv.git / blobdiff