sys/mips/cavium/octeon_rnd.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2010 Juli Mallett <jmallett@FreeBSD.org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  * $FreeBSD$
  29  */
  30
  31 #include <sys/cdefs.h>
  32 __FBSDID("$FreeBSD$");
  33
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/bus.h>
  37 #include <sys/clock.h>
  38 #include <sys/kernel.h>
  39 #include <sys/lock.h>
  40 #include <sys/module.h>
  41 #include <sys/random.h>
  42
  43 #include <contrib/octeon-sdk/cvmx.h>
  44 #include <contrib/octeon-sdk/cvmx-rng.h>
  45
  46 #define OCTEON_RND_WORDS        2
  47
  48 struct octeon_rnd_softc {
  49         uint64_t sc_entropy[OCTEON_RND_WORDS];
  50         struct callout sc_callout;
  51 };
  52
  53 static void     octeon_rnd_identify(driver_t *drv, device_t parent);
  54 static int      octeon_rnd_attach(device_t dev);
  55 static int      octeon_rnd_probe(device_t dev);
  56 static int      octeon_rnd_detach(device_t dev);
  57
  58 static void     octeon_rnd_harvest(void *);
  59
  60 static device_method_t octeon_rnd_methods[] = {
  61         /* Device interface */
  62         DEVMETHOD(device_identify,      octeon_rnd_identify),
  63         DEVMETHOD(device_probe,         octeon_rnd_probe),
  64         DEVMETHOD(device_attach,        octeon_rnd_attach),
  65         DEVMETHOD(device_detach,        octeon_rnd_detach),
  66
  67         { 0, 0 }
  68 };
  69
  70 static driver_t octeon_rnd_driver = {
  71         "rnd",
  72         octeon_rnd_methods,
  73         sizeof (struct octeon_rnd_softc)
  74 };
  75 static devclass_t octeon_rnd_devclass;
  76 DRIVER_MODULE(rnd, nexus, octeon_rnd_driver, octeon_rnd_devclass, 0, 0);
  77
  78 static void
  79 octeon_rnd_identify(driver_t *drv, device_t parent)
  80 {
  81         BUS_ADD_CHILD(parent, 0, "rnd", 0);
  82 }
  83
  84 static int
  85 octeon_rnd_probe(device_t dev)
  86 {
  87         if (device_get_unit(dev) != 0)
  88                 return (ENXIO);
  89
  90         device_set_desc(dev, "Cavium Octeon Random Number Generator");
  91         return (BUS_PROBE_NOWILDCARD);
  92 }
  93
  94 static int
  95 octeon_rnd_attach(device_t dev)
  96 {
  97         struct octeon_rnd_softc *sc;
  98
  99         sc = device_get_softc(dev);
 100         callout_init(&sc->sc_callout, 1);
 101         callout_reset(&sc->sc_callout, hz * 5, octeon_rnd_harvest, sc);
 102
 103         cvmx_rng_enable();
 104
 105         return (0);
 106 }
 107
 108 static int
 109 octeon_rnd_detach(device_t dev)
 110 {
 111         struct octeon_rnd_softc *sc;
 112
 113         sc = device_get_softc(dev);
 114
 115         callout_stop(&sc->sc_callout);
 116
 117         return (0);
 118 }
 119
 120 static void
 121 octeon_rnd_harvest(void *arg)
 122 {
 123         struct octeon_rnd_softc *sc;
 124         unsigned i;
 125
 126         sc = arg;
 127
 128         for (i = 0; i < OCTEON_RND_WORDS; i++)
 129                 sc->sc_entropy[i] = cvmx_rng_get_random64();
 130         /* MarkM: FIX!! Check that this does not swamp the harvester! */
 131         random_harvest_queue(sc->sc_entropy, sizeof sc->sc_entropy, RANDOM_PURE_OCTEON);
 132
 133         callout_reset(&sc->sc_callout, hz * 5, octeon_rnd_harvest, sc);
 134 }