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/fdt/fdt_common.h> 49#include <dev/ofw/ofw_bus.h> 50#include <dev/ofw/ofw_bus_subr.h> 51 52 53struct aml8726_rng_softc { 54 device_t dev; 55 struct resource *res[1]; 56 struct callout co; 57 int ticks; 58}; 59 60static struct resource_spec aml8726_rng_spec[] = { 61 { SYS_RES_MEMORY, 0, RF_ACTIVE }, 62 { -1, 0 } 63}; 64 65#define AML_RNG_0_REG 0 66#define AML_RNG_1_REG 4 67 68#define CSR_READ_4(sc, reg) bus_read_4((sc)->res[0], reg) 69 70static void 71aml8726_rng_harvest(void *arg) 72{ 73 struct aml8726_rng_softc *sc = arg; 74 uint32_t rn[2]; 75 76 rn[0] = CSR_READ_4(sc, AML_RNG_0_REG); 77 rn[1] = CSR_READ_4(sc, AML_RNG_1_REG); 78 79 random_harvest(rn, sizeof(rn), sizeof(rn) * NBBY / 2, 80 RANDOM_PURE_AML8726); 81 82 callout_reset(&sc->co, sc->ticks, aml8726_rng_harvest, sc); 83} 84 85static int 86aml8726_rng_probe(device_t dev) 87{ 88 89 if (!ofw_bus_status_okay(dev)) 90 return (ENXIO); 91 92 if (!ofw_bus_is_compatible(dev, "amlogic,aml8726-rng")) 93 return (ENXIO); 94 95 device_set_desc(dev, "Amlogic aml8726 RNG"); 96 97 return (BUS_PROBE_DEFAULT); 98} 99 100static int 101aml8726_rng_attach(device_t dev) 102{ 103 struct aml8726_rng_softc *sc = device_get_softc(dev); 104 105 sc->dev = dev; 106 107 if (bus_alloc_resources(dev, aml8726_rng_spec, sc->res)) { 108 device_printf(dev, "can not allocate resources for device\n"); 109 return (ENXIO); 110 } 111 112 /* Install a periodic collector for the RNG */ 113 if (hz > 100) 114 sc->ticks = hz / 100; 115 else 116 sc->ticks = 1; 117 118 callout_init(&sc->co, 1); 119 callout_reset(&sc->co, sc->ticks, aml8726_rng_harvest, sc); 120 121 return (0); 122} 123 124static int 125aml8726_rng_detach(device_t dev) 126{ 127 struct aml8726_rng_softc *sc = device_get_softc(dev); 128 129 callout_drain(&sc->co); 130 131 bus_release_resources(dev, aml8726_rng_spec, sc->res); 132 133 return (0); 134} 135 136static device_method_t aml8726_rng_methods[] = { 137 /* Device interface */ 138 DEVMETHOD(device_probe, aml8726_rng_probe), 139 DEVMETHOD(device_attach, aml8726_rng_attach), 140 DEVMETHOD(device_detach, aml8726_rng_detach), 141 142 DEVMETHOD_END 143}; 144 145static driver_t aml8726_rng_driver = { 146 "rng", 147 aml8726_rng_methods, 148 sizeof(struct aml8726_rng_softc), 149}; 150 151static devclass_t aml8726_rng_devclass; 152 153DRIVER_MODULE(aml8726_rng, simplebus, aml8726_rng_driver, 154 aml8726_rng_devclass, 0, 0); 155MODULE_DEPEND(aml8726_rng, random, 1, 1, 1); 156