1 /* $NetBSD: ingenic_rng.c,v 1.5 2020/04/30 03:40:53 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2015 Michael McConville 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __KERNEL_RCSID(0, "$NetBSD: ingenic_rng.c,v 1.5 2020/04/30 03:40:53 riastradh Exp $"); 31 32 /* 33 * adapted from Jared McNeill's amlogic_rng.c 34 */ 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/device.h> 39 #include <sys/mutex.h> 40 #include <sys/kernel.h> 41 #include <sys/mutex.h> 42 #include <sys/bus.h> 43 #include <sys/rndsource.h> 44 45 #include <mips/ingenic/ingenic_var.h> 46 #include <mips/ingenic/ingenic_regs.h> 47 48 #include "opt_ingenic.h" 49 50 struct ingenic_rng_softc; 51 52 static int ingenic_rng_match(device_t, cfdata_t, void *); 53 static void ingenic_rng_attach(device_t, device_t, void *); 54 55 static void ingenic_rng_get(size_t, void *); 56 57 struct ingenic_rng_softc { 58 device_t sc_dev; 59 bus_space_tag_t sc_bst; 60 bus_space_handle_t sc_bsh; 61 62 kmutex_t sc_lock; 63 krndsource_t sc_rndsource; 64 }; 65 66 CFATTACH_DECL_NEW(ingenic_rng, sizeof(struct ingenic_rng_softc), 67 ingenic_rng_match, ingenic_rng_attach, NULL, NULL); 68 69 static int 70 ingenic_rng_match(device_t parent, cfdata_t cf, void *aux) 71 { 72 const struct apbus_attach_args *aa = aux; 73 74 return !(strcmp(aa->aa_name, "jzrng")); 75 } 76 77 static void 78 ingenic_rng_attach(device_t parent, device_t self, void *aux) 79 { 80 struct ingenic_rng_softc * const sc = device_private(self); 81 const struct apbus_attach_args * const aa = aux; 82 bus_addr_t addr = aa->aa_addr; 83 int error; 84 85 sc->sc_dev = self; 86 sc->sc_bst = aa->aa_bst; 87 if (addr == 0) 88 addr = JZ_RNG; 89 90 error = bus_space_map(aa->aa_bst, addr, 4, 0, &sc->sc_bsh); 91 if (error) { 92 aprint_error_dev(self, 93 "can't map registers for %s: %d\n", aa->aa_name, error); 94 return; 95 } 96 97 mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_VM); 98 99 aprint_naive(": Ingenic random number generator\n"); 100 aprint_normal(": Ingenic random number generator\n"); 101 102 rndsource_setcb(&sc->sc_rndsource, ingenic_rng_get, sc); 103 rnd_attach_source(&sc->sc_rndsource, device_xname(self), RND_TYPE_RNG, 104 RND_FLAG_COLLECT_VALUE|RND_FLAG_HASCB); 105 } 106 107 static void 108 ingenic_rng_get(size_t bytes_wanted, void *priv) 109 { 110 struct ingenic_rng_softc * const sc = priv; 111 uint32_t data; 112 113 mutex_spin_enter(&sc->sc_lock); 114 while (bytes_wanted) { 115 data = bus_space_read_4(sc->sc_bst, sc->sc_bsh, 0); 116 delay(1); 117 rnd_add_data_sync(&sc->sc_rndsource, &data, sizeof(data), 118 sizeof(data) * NBBY); 119 bytes_wanted -= MIN(bytes_wanted, sizeof(data)); 120 } 121 explicit_memset(&data, 0, sizeof(data)); 122 mutex_spin_exit(&sc->sc_lock); 123 } 124