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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /drivers/char/hw_random/amd-rng.c
Initial import
Diffstat (limited to 'drivers/char/hw_random/amd-rng.c')
-rw-r--r--drivers/char/hw_random/amd-rng.c169
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 000000000..48f6a83cd
--- /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;
+
+ pr_info("AMD768 RNG detected\n");
+ err = hwrng_register(&amd_rng);
+ if (err) {
+ pr_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");