Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / char / hw_random / pseries-rng.c

diff --git a/kernel/drivers/char/hw_random/pseries-rng.c b/kernel/drivers/char/hw_random/pseries-rng.c
new file mode 100644 (file)
index 0000000..63ce51d
--- /dev/null
+++ b/kernel/drivers/char/hw_random/pseries-rng.c
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2010 Michael Neuling IBM Corporation
+ *
+ * Driver for the pseries hardware RNG for POWER7+ and above
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/hw_random.h>
+#include <asm/vio.h>
+
+
+static int pseries_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
+{
+       u64 buffer[PLPAR_HCALL_BUFSIZE];
+       size_t size = max < 8 ? max : 8;
+       int rc;
+
+       rc = plpar_hcall(H_RANDOM, (unsigned long *)buffer);
+       if (rc != H_SUCCESS) {
+               pr_err_ratelimited("H_RANDOM call failed %d\n", rc);
+               return -EIO;
+       }
+       memcpy(data, buffer, size);
+
+       /* The hypervisor interface returns 64 bits */
+       return size;
+}
+
+/**
+ * pseries_rng_get_desired_dma - Return desired DMA allocate for CMO operations
+ *
+ * This is a required function for a driver to operate in a CMO environment
+ * but this device does not make use of DMA allocations, return 0.
+ *
+ * Return value:
+ *     Number of bytes of IO data the driver will need to perform well -> 0
+ */
+static unsigned long pseries_rng_get_desired_dma(struct vio_dev *vdev)
+{
+       return 0;
+};
+
+static struct hwrng pseries_rng = {
+       .name           = KBUILD_MODNAME,
+       .read           = pseries_rng_read,
+};
+
+static int pseries_rng_probe(struct vio_dev *dev,
+               const struct vio_device_id *id)
+{
+       return hwrng_register(&pseries_rng);
+}
+
+static int pseries_rng_remove(struct vio_dev *dev)
+{
+       hwrng_unregister(&pseries_rng);
+       return 0;
+}
+
+static struct vio_device_id pseries_rng_driver_ids[] = {
+       { "ibm,random-v1", "ibm,random"},
+       { "", "" }
+};
+MODULE_DEVICE_TABLE(vio, pseries_rng_driver_ids);
+
+static struct vio_driver pseries_rng_driver = {
+       .name = KBUILD_MODNAME,
+       .probe = pseries_rng_probe,
+       .remove = pseries_rng_remove,
+       .get_desired_dma = pseries_rng_get_desired_dma,
+       .id_table = pseries_rng_driver_ids
+};
+
+static int __init rng_init(void)
+{
+       pr_info("Registering IBM pSeries RNG driver\n");
+       return vio_register_driver(&pseries_rng_driver);
+}
+
+module_init(rng_init);
+
+static void __exit rng_exit(void)
+{
+       vio_unregister_driver(&pseries_rng_driver);
+}
+module_exit(rng_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michael Neuling <mikey@neuling.org>");
+MODULE_DESCRIPTION("H/W RNG driver for IBM pSeries processors");