155 lines
3.8 KiB
C
155 lines
3.8 KiB
C
/*-
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* Copyright 2014 John Wehle <john@feith.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Amlogic aml8726 random number generator driver.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/conf.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/resource.h>
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#include <sys/rman.h>
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#include <sys/random.h>
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#include <machine/bus.h>
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#include <dev/ofw/ofw_bus.h>
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#include <dev/ofw/ofw_bus_subr.h>
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struct aml8726_rng_softc {
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device_t dev;
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struct resource *res[1];
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struct callout co;
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int ticks;
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};
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static struct resource_spec aml8726_rng_spec[] = {
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{ SYS_RES_MEMORY, 0, RF_ACTIVE },
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{ -1, 0 }
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};
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#define AML_RNG_0_REG 0
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#define AML_RNG_1_REG 4
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#define CSR_READ_4(sc, reg) bus_read_4((sc)->res[0], reg)
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static void
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aml8726_rng_harvest(void *arg)
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{
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struct aml8726_rng_softc *sc = arg;
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uint32_t rn[2];
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rn[0] = CSR_READ_4(sc, AML_RNG_0_REG);
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rn[1] = CSR_READ_4(sc, AML_RNG_1_REG);
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random_harvest(rn, sizeof(rn), sizeof(rn) * NBBY / 2,
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RANDOM_PURE_AML8726);
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callout_reset(&sc->co, sc->ticks, aml8726_rng_harvest, sc);
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}
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static int
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aml8726_rng_probe(device_t dev)
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{
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if (!ofw_bus_status_okay(dev))
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return (ENXIO);
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if (!ofw_bus_is_compatible(dev, "amlogic,aml8726-rng"))
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return (ENXIO);
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device_set_desc(dev, "Amlogic aml8726 RNG");
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return (BUS_PROBE_DEFAULT);
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}
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static int
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aml8726_rng_attach(device_t dev)
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{
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struct aml8726_rng_softc *sc = device_get_softc(dev);
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sc->dev = dev;
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if (bus_alloc_resources(dev, aml8726_rng_spec, sc->res)) {
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device_printf(dev, "can not allocate resources for device\n");
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return (ENXIO);
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}
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/* Install a periodic collector for the RNG */
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if (hz > 100)
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sc->ticks = hz / 100;
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else
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sc->ticks = 1;
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callout_init(&sc->co, 1);
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callout_reset(&sc->co, sc->ticks, aml8726_rng_harvest, sc);
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return (0);
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}
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static int
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aml8726_rng_detach(device_t dev)
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{
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struct aml8726_rng_softc *sc = device_get_softc(dev);
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callout_drain(&sc->co);
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bus_release_resources(dev, aml8726_rng_spec, sc->res);
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return (0);
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}
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static device_method_t aml8726_rng_methods[] = {
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/* Device interface */
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DEVMETHOD(device_probe, aml8726_rng_probe),
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DEVMETHOD(device_attach, aml8726_rng_attach),
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DEVMETHOD(device_detach, aml8726_rng_detach),
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DEVMETHOD_END
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};
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static driver_t aml8726_rng_driver = {
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"rng",
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aml8726_rng_methods,
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sizeof(struct aml8726_rng_softc),
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};
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static devclass_t aml8726_rng_devclass;
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DRIVER_MODULE(aml8726_rng, simplebus, aml8726_rng_driver,
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aml8726_rng_devclass, 0, 0);
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MODULE_DEPEND(aml8726_rng, random, 1, 1, 1);
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