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-rw-r--r--drivers/char/hw_random/geode-rng.c161
1 files changed, 161 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..159baf00a
--- /dev/null
+++ b/drivers/char/hw_random/geode-rng.c
@@ -0,0 +1,161 @@
+/*
+ * 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);
+
+struct amd_geode_priv {
+ struct pci_dev *pcidev;
+ void __iomem *membase;
+};
+
+static int geode_rng_data_read(struct hwrng *rng, u32 *data)
+{
+ struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv;
+ void __iomem *mem = priv->membase;
+
+ *data = readl(mem + GEODE_RNG_DATA_REG);
+
+ return 4;
+}
+
+static int geode_rng_data_present(struct hwrng *rng, int wait)
+{
+ struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv;
+ void __iomem *mem = priv->membase;
+ 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 geode_rng_init(void)
+{
+ int err = -ENODEV;
+ struct pci_dev *pdev = NULL;
+ const struct pci_device_id *ent;
+ void __iomem *mem;
+ unsigned long rng_base;
+ struct amd_geode_priv *priv;
+
+ for_each_pci_dev(pdev) {
+ ent = pci_match_id(pci_tbl, pdev);
+ if (ent)
+ goto found;
+ }
+ /* Device not found. */
+ return err;
+
+found:
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv) {
+ err = -ENOMEM;
+ goto put_dev;
+ }
+
+ rng_base = pci_resource_start(pdev, 0);
+ if (rng_base == 0)
+ goto free_priv;
+ err = -ENOMEM;
+ mem = ioremap(rng_base, 0x58);
+ if (!mem)
+ goto free_priv;
+
+ geode_rng.priv = (unsigned long)priv;
+ priv->membase = mem;
+ priv->pcidev = pdev;
+
+ 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;
+ }
+ return err;
+
+err_unmap:
+ iounmap(mem);
+free_priv:
+ kfree(priv);
+put_dev:
+ pci_dev_put(pdev);
+ return err;
+}
+
+static void __exit geode_rng_exit(void)
+{
+ struct amd_geode_priv *priv;
+
+ priv = (struct amd_geode_priv *)geode_rng.priv;
+ hwrng_unregister(&geode_rng);
+ iounmap(priv->membase);
+ pci_dev_put(priv->pcidev);
+ kfree(priv);
+}
+
+module_init(geode_rng_init);
+module_exit(geode_rng_exit);
+
+MODULE_DESCRIPTION("H/W RNG driver for AMD Geode LX CPUs");
+MODULE_LICENSE("GPL");