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- /*
- * 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");
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