// SPDX-License-Identifier: GPL-2.0-or-later
|
/*
|
* Copyright 2013 Michael Ellerman, Guo Chao, IBM Corp.
|
*/
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
#include <linux/module.h>
|
#include <linux/mod_devicetable.h>
|
#include <linux/kernel.h>
|
#include <linux/platform_device.h>
|
#include <linux/random.h>
|
#include <linux/hw_random.h>
|
|
static int powernv_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
|
{
|
unsigned long *buf;
|
int i, len;
|
|
/* We rely on rng_buffer_size() being >= sizeof(unsigned long) */
|
len = max / sizeof(unsigned long);
|
|
buf = (unsigned long *)data;
|
|
for (i = 0; i < len; i++)
|
powernv_get_random_long(buf++);
|
|
return len * sizeof(unsigned long);
|
}
|
|
static struct hwrng powernv_hwrng = {
|
.name = "powernv-rng",
|
.read = powernv_rng_read,
|
};
|
|
static int powernv_rng_probe(struct platform_device *pdev)
|
{
|
int rc;
|
|
rc = devm_hwrng_register(&pdev->dev, &powernv_hwrng);
|
if (rc) {
|
/* We only register one device, ignore any others */
|
if (rc == -EEXIST)
|
rc = -ENODEV;
|
|
return rc;
|
}
|
|
pr_info("Registered powernv hwrng.\n");
|
|
return 0;
|
}
|
|
static const struct of_device_id powernv_rng_match[] = {
|
{ .compatible = "ibm,power-rng",},
|
{},
|
};
|
MODULE_DEVICE_TABLE(of, powernv_rng_match);
|
|
static struct platform_driver powernv_rng_driver = {
|
.driver = {
|
.name = "powernv_rng",
|
.of_match_table = powernv_rng_match,
|
},
|
.probe = powernv_rng_probe,
|
};
|
module_platform_driver(powernv_rng_driver);
|
|
MODULE_LICENSE("GPL");
|
MODULE_DESCRIPTION("Bare metal HWRNG driver for POWER7+ and above");
|
