1/*- 2 * Copyright 2014 John Wehle <john@feith.com> 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 27/* 28 * Amlogic aml8726 random number generator driver. 29 */ 30 31#include <sys/cdefs.h> 32__FBSDID("$FreeBSD$"); 33 34#include <sys/param.h> 35#include <sys/systm.h> 36#include <sys/conf.h> 37#include <sys/bus.h> 38#include <sys/kernel.h> 39#include <sys/module.h> 40#include <sys/lock.h> 41#include <sys/mutex.h> 42#include <sys/resource.h> 43#include <sys/rman.h> 44#include <sys/random.h> 45 46#include <machine/bus.h> 47 48#include <dev/ofw/ofw_bus.h> 49#include <dev/ofw/ofw_bus_subr.h> 50 51 52struct aml8726_rng_softc { 53 device_t dev; 54 struct resource *res[1]; 55 struct callout co; 56 int ticks; 57}; 58 59static struct resource_spec aml8726_rng_spec[] = { 60 { SYS_RES_MEMORY, 0, RF_ACTIVE }, 61 { -1, 0 } 62}; 63 64#define AML_RNG_0_REG 0 65#define AML_RNG_1_REG 4 66 67#define CSR_READ_4(sc, reg) bus_read_4((sc)->res[0], reg) 68 69static void 70aml8726_rng_harvest(void *arg) 71{ 72 struct aml8726_rng_softc *sc = arg; 73 uint32_t rn[2]; 74 75 rn[0] = CSR_READ_4(sc, AML_RNG_0_REG); 76 rn[1] = CSR_READ_4(sc, AML_RNG_1_REG); 77 78 random_harvest(rn, sizeof(rn), RANDOM_PURE_AML8726); 79 80 callout_reset(&sc->co, sc->ticks, aml8726_rng_harvest, sc); 81} 82 83static int 84aml8726_rng_probe(device_t dev) 85{ 86 87 if (!ofw_bus_status_okay(dev)) 88 return (ENXIO); 89 90 if (!ofw_bus_is_compatible(dev, "amlogic,aml8726-rng")) 91 return (ENXIO); 92 93 device_set_desc(dev, "Amlogic aml8726 RNG"); 94 95 return (BUS_PROBE_DEFAULT); 96} 97 98static int 99aml8726_rng_attach(device_t dev) 100{ 101 struct aml8726_rng_softc *sc = device_get_softc(dev); 102 103 sc->dev = dev; 104 105 if (bus_alloc_resources(dev, aml8726_rng_spec, sc->res)) { 106 device_printf(dev, "can not allocate resources for device\n"); 107 return (ENXIO); 108 } 109 110 /* Install a periodic collector for the RNG */ 111 if (hz > 100) 112 sc->ticks = hz / 100; 113 else 114 sc->ticks = 1; 115 116 callout_init(&sc->co, 1); 117 callout_reset(&sc->co, sc->ticks, aml8726_rng_harvest, sc); 118 119 return (0); 120} 121 122static int 123aml8726_rng_detach(device_t dev) 124{ 125 struct aml8726_rng_softc *sc = device_get_softc(dev); 126 127 callout_drain(&sc->co); 128 129 bus_release_resources(dev, aml8726_rng_spec, sc->res); 130 131 return (0); 132} 133 134static device_method_t aml8726_rng_methods[] = { 135 /* Device interface */ 136 DEVMETHOD(device_probe, aml8726_rng_probe), 137 DEVMETHOD(device_attach, aml8726_rng_attach), 138 DEVMETHOD(device_detach, aml8726_rng_detach), 139 140 DEVMETHOD_END 141}; 142 143static driver_t aml8726_rng_driver = { 144 "rng", 145 aml8726_rng_methods, 146 sizeof(struct aml8726_rng_softc), 147}; 148 149static devclass_t aml8726_rng_devclass; 150 151DRIVER_MODULE(aml8726_rng, simplebus, aml8726_rng_driver, 152 aml8726_rng_devclass, 0, 0); 153MODULE_DEPEND(aml8726_rng, random, 1, 1, 1); 154