octeon_rnd.c revision 255362 
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 255362 2013-09-07 14:15:13Z markm $
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/sys/mips/cavium/octeon_rnd.c 255362 2013-09-07 14:15:13Z markm $");
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/*
45 * XXX
46 * random_harvest(9) says to call it with no more than 16 bytes, but at least
47 * safe(4) seems to violate that rule.
48 */
49#define	OCTEON_RND_WORDS	2
50
51struct octeon_rnd_softc {
52	uint64_t sc_entropy[OCTEON_RND_WORDS];
53	struct callout sc_callout;
54};
55
56static void	octeon_rnd_identify(driver_t *drv, device_t parent);
57static int	octeon_rnd_attach(device_t dev);
58static int	octeon_rnd_probe(device_t dev);
59static int	octeon_rnd_detach(device_t dev);
60
61static void	octeon_rnd_harvest(void *);
62
63static device_method_t octeon_rnd_methods[] = {
64	/* Device interface */
65	DEVMETHOD(device_identify,	octeon_rnd_identify),
66	DEVMETHOD(device_probe,		octeon_rnd_probe),
67	DEVMETHOD(device_attach,	octeon_rnd_attach),
68	DEVMETHOD(device_detach,	octeon_rnd_detach),
69
70	{ 0, 0 }
71};
72
73static driver_t octeon_rnd_driver = {
74	"rnd",
75	octeon_rnd_methods,
76	sizeof (struct octeon_rnd_softc)
77};
78static devclass_t octeon_rnd_devclass;
79DRIVER_MODULE(rnd, nexus, octeon_rnd_driver, octeon_rnd_devclass, 0, 0);
80
81static void
82octeon_rnd_identify(driver_t *drv, device_t parent)
83{
84	BUS_ADD_CHILD(parent, 0, "rnd", 0);
85}
86
87static int
88octeon_rnd_probe(device_t dev)
89{
90	if (device_get_unit(dev) != 0)
91		return (ENXIO);
92
93	device_set_desc(dev, "Cavium Octeon Random Number Generator");
94	return (0);
95}
96
97static int
98octeon_rnd_attach(device_t dev)
99{
100	struct octeon_rnd_softc *sc;
101
102	sc = device_get_softc(dev);
103	callout_init(&sc->sc_callout, CALLOUT_MPSAFE);
104	callout_reset(&sc->sc_callout, hz * 5, octeon_rnd_harvest, sc);
105
106	cvmx_rng_enable();
107
108	return (0);
109}
110
111static int
112octeon_rnd_detach(device_t dev)
113{
114	struct octeon_rnd_softc *sc;
115
116	sc = device_get_softc(dev);
117
118	callout_stop(&sc->sc_callout);
119
120	return (0);
121}
122
123static void
124octeon_rnd_harvest(void *arg)
125{
126	struct octeon_rnd_softc *sc;
127	unsigned i;
128
129	sc = arg;
130
131	for (i = 0; i < OCTEON_RND_WORDS; i++)
132		sc->sc_entropy[i] = cvmx_rng_get_random64();
133	random_harvest(sc->sc_entropy, sizeof sc->sc_entropy,
134		       (sizeof(sc->sc_entropy)*8)/2, 0, RANDOM_PURE);
135
136	callout_reset(&sc->sc_callout, hz * 5, octeon_rnd_harvest, sc);
137}
138