octeon_rnd.c revision 283291 
1/*-
2 * Copyright (c) 2010 Juli Mallett <jmallett@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/mips/cavium/octeon_rnd.c 283291 2015-05-22 17:05:21Z jkim $
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/sys/mips/cavium/octeon_rnd.c 283291 2015-05-22 17:05:21Z jkim $");
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/bus.h>
35#include <sys/clock.h>
36#include <sys/kernel.h>
37#include <sys/lock.h>
38#include <sys/module.h>
39#include <sys/random.h>
40
41#include <contrib/octeon-sdk/cvmx.h>
42#include <contrib/octeon-sdk/cvmx-rng.h>
43
44#define	OCTEON_RND_WORDS	2
45
46struct octeon_rnd_softc {
47	uint64_t sc_entropy[OCTEON_RND_WORDS];
48	struct callout sc_callout;
49};
50
51static void	octeon_rnd_identify(driver_t *drv, device_t parent);
52static int	octeon_rnd_attach(device_t dev);
53static int	octeon_rnd_probe(device_t dev);
54static int	octeon_rnd_detach(device_t dev);
55
56static void	octeon_rnd_harvest(void *);
57
58static device_method_t octeon_rnd_methods[] = {
59	/* Device interface */
60	DEVMETHOD(device_identify,	octeon_rnd_identify),
61	DEVMETHOD(device_probe,		octeon_rnd_probe),
62	DEVMETHOD(device_attach,	octeon_rnd_attach),
63	DEVMETHOD(device_detach,	octeon_rnd_detach),
64
65	{ 0, 0 }
66};
67
68static driver_t octeon_rnd_driver = {
69	"rnd",
70	octeon_rnd_methods,
71	sizeof (struct octeon_rnd_softc)
72};
73static devclass_t octeon_rnd_devclass;
74DRIVER_MODULE(rnd, nexus, octeon_rnd_driver, octeon_rnd_devclass, 0, 0);
75
76static void
77octeon_rnd_identify(driver_t *drv, device_t parent)
78{
79	BUS_ADD_CHILD(parent, 0, "rnd", 0);
80}
81
82static int
83octeon_rnd_probe(device_t dev)
84{
85	if (device_get_unit(dev) != 0)
86		return (ENXIO);
87
88	device_set_desc(dev, "Cavium Octeon Random Number Generator");
89	return (BUS_PROBE_NOWILDCARD);
90}
91
92static int
93octeon_rnd_attach(device_t dev)
94{
95	struct octeon_rnd_softc *sc;
96
97	sc = device_get_softc(dev);
98	callout_init(&sc->sc_callout, 1);
99	callout_reset(&sc->sc_callout, hz * 5, octeon_rnd_harvest, sc);
100
101	cvmx_rng_enable();
102
103	return (0);
104}
105
106static int
107octeon_rnd_detach(device_t dev)
108{
109	struct octeon_rnd_softc *sc;
110
111	sc = device_get_softc(dev);
112
113	callout_stop(&sc->sc_callout);
114
115	return (0);
116}
117
118static void
119octeon_rnd_harvest(void *arg)
120{
121	struct octeon_rnd_softc *sc;
122	unsigned i;
123
124	sc = arg;
125
126	for (i = 0; i < OCTEON_RND_WORDS; i++)
127		sc->sc_entropy[i] = cvmx_rng_get_random64();
128	random_harvest(sc->sc_entropy, sizeof sc->sc_entropy,
129		       (sizeof(sc->sc_entropy)*8)/2, RANDOM_PURE_OCTEON);
130
131	callout_reset(&sc->sc_callout, hz * 5, octeon_rnd_harvest, sc);
132}
133