sys/mips/cavium/octeon_rnd.c

   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  * $FreeBSD$
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  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
  46 struct octeon_rnd_softc {
  47         uint64_t sc_entropy[OCTEON_RND_WORDS];
  48         struct callout sc_callout;
  49 };
  50
  51 static void     octeon_rnd_identify(driver_t *drv, device_t parent);
  52 static int      octeon_rnd_attach(device_t dev);
  53 static int      octeon_rnd_probe(device_t dev);
  54 static int      octeon_rnd_detach(device_t dev);
  55
  56 static void     octeon_rnd_harvest(void *);
  57
  58 static 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
  68 static driver_t octeon_rnd_driver = {
  69         "rnd",
  70         octeon_rnd_methods,
  71         sizeof (struct octeon_rnd_softc)
  72 };
  73 static devclass_t octeon_rnd_devclass;
  74 DRIVER_MODULE(rnd, nexus, octeon_rnd_driver, octeon_rnd_devclass, 0, 0);
  75
  76 static void
  77 octeon_rnd_identify(driver_t *drv, device_t parent)
  78 {
  79         BUS_ADD_CHILD(parent, 0, "rnd", 0);
  80 }
  81
  82 static int
  83 octeon_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 (0);
  90 }
  91
  92 static int
  93 octeon_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, CALLOUT_MPSAFE);
  99         callout_reset(&sc->sc_callout, hz * 5, octeon_rnd_harvest, sc);
 100
 101         cvmx_rng_enable();
 102
 103         return (0);
 104 }
 105
 106 static int
 107 octeon_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
 118 static void
 119 octeon_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 }