[PATCH] Add AMD HW RNG driver

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 166 insertions, 0 deletions

diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index e9ae4b1313a7..950247313cad 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -22,3 +22,16 @@ config HW_RANDOM_INTEL
           module will be called intel-rng.
 
           If unsure, say Y.
+
+config HW_RANDOM_AMD
+        tristate "AMD HW Random Number Generator support"
+        depends on HW_RANDOM && X86 && PCI
+        default y
+        ---help---
+          This driver provides kernel-side support for the Random Number
+          Generator hardware found on AMD 76x-based motherboards.
+
+          To compile this driver as a module, choose M here: the
+          module will be called amd-rng.
+
+          If unsure, say Y.
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index d3118e3750a4..40dbc097a5d6 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -4,3 +4,4 @@
 
 obj-$(CONFIG_HW_RANDOM) += core.o
 obj-$(CONFIG_HW_RANDOM_INTEL) += intel-rng.o
+obj-$(CONFIG_HW_RANDOM_AMD) += amd-rng.o
diff --git a/drivers/char/hw_random/amd-rng.c b/drivers/char/hw_random/amd-rng.c
new file mode 100644
index 000000000000..71e4e0f3fd54
--- /dev/null
+++ b/drivers/char/hw_random/amd-rng.c
@@ -0,0 +1,152 @@
+/*
+ * 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 <alan@redhat.com>
+ *
+ * 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 <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[] = {
+        { 0x1022, 0x7443, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0, },
+        { 0x1022, 0x746b, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 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)
+{
+        u32 pmbase = (u32)rng->priv;
+
+        return !!(inl(pmbase + 0xF4) & 1);
+}
+
+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;
+        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);
+                goto out;
+        }
+out:
+        return err;
+}
+
+static void __exit mod_exit(void)
+{
+        hwrng_unregister(&amd_rng);
+}
+
+subsys_initcall(mod_init);
+module_exit(mod_exit);
+
+MODULE_AUTHOR("The Linux Kernel team");
+MODULE_DESCRIPTION("H/W RNG driver for AMD chipsets");
+MODULE_LICENSE("GPL");