FreeBSD/Linux Kernel Cross Reference
sys/mips/cavium/octeon_rnd.c

     /*-
      * Copyright (c) 2010 Juli Mallett <jmallett@FreeBSD.org>
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD: releng/9.0/sys/mips/cavium/octeon_rnd.c 210311 2010-07-20 19:25:11Z jmallett $
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/9.0/sys/mips/cavium/octeon_rnd.c 210311 2010-07-20 19:25:11Z jmallett $");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/bus.h>
    #include <sys/clock.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/module.h>
    #include <sys/random.h>
    
    #include <contrib/octeon-sdk/cvmx.h>
    #include <contrib/octeon-sdk/cvmx-rng.h>
    
    /*
     * XXX
     * random_harvest(9) says to call it with no more than 16 bytes, but at least
     * safe(4) seems to violate that rule.
     */
    #define OCTEON_RND_WORDS        2
    
    struct octeon_rnd_softc {
            uint64_t sc_entropy[OCTEON_RND_WORDS];
            struct callout sc_callout;
    };
    
    static void     octeon_rnd_identify(driver_t *drv, device_t parent);
    static int      octeon_rnd_attach(device_t dev);
    static int      octeon_rnd_probe(device_t dev);
    static int      octeon_rnd_detach(device_t dev);
    
    static void     octeon_rnd_harvest(void *);
    
    static device_method_t octeon_rnd_methods[] = {
            /* Device interface */
            DEVMETHOD(device_identify,      octeon_rnd_identify),
            DEVMETHOD(device_probe,         octeon_rnd_probe),
            DEVMETHOD(device_attach,        octeon_rnd_attach),
            DEVMETHOD(device_detach,        octeon_rnd_detach),
    
            { 0, 0 }
    };
    
    static driver_t octeon_rnd_driver = {
            "rnd",
            octeon_rnd_methods,
            sizeof (struct octeon_rnd_softc)
    };
    static devclass_t octeon_rnd_devclass;
    DRIVER_MODULE(rnd, nexus, octeon_rnd_driver, octeon_rnd_devclass, 0, 0);
    
    static void
    octeon_rnd_identify(driver_t *drv, device_t parent)
    {
            BUS_ADD_CHILD(parent, 0, "rnd", 0);
    }
    
    static int
    octeon_rnd_probe(device_t dev)
    {
            if (device_get_unit(dev) != 0)
                    return (ENXIO);
    
            device_set_desc(dev, "Cavium Octeon Random Number Generator");
            return (0);
    }
    
    static int
    octeon_rnd_attach(device_t dev)
    {
           struct octeon_rnd_softc *sc;
   
           sc = device_get_softc(dev);
           callout_init(&sc->sc_callout, CALLOUT_MPSAFE);
           callout_reset(&sc->sc_callout, hz * 5, octeon_rnd_harvest, sc);
   
           cvmx_rng_enable();
   
           return (0);
   }
   
   static int
   octeon_rnd_detach(device_t dev)
   {
           struct octeon_rnd_softc *sc;
   
           sc = device_get_softc(dev);
   
           callout_stop(&sc->sc_callout);
   
           return (0);
   }
   
   static void
   octeon_rnd_harvest(void *arg)
   {
           struct octeon_rnd_softc *sc;
           unsigned i;
   
           sc = arg;
   
           for (i = 0; i < OCTEON_RND_WORDS; i++)
                   sc->sc_entropy[i] = cvmx_rng_get_random64();
           random_harvest(sc->sc_entropy, sizeof sc->sc_entropy,
                          sizeof sc->sc_entropy * 8, 0, RANDOM_PURE);
   
           callout_reset(&sc->sc_callout, hz * 5, octeon_rnd_harvest, sc);
   }

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