1 /* $NetBSD: g2rtc.c,v 1.2 2008/01/06 10:33:24 he Exp $ */ 2 3 /*- 4 * Copyright (c) 2002 The NetBSD Foundation, Inc. 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 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the NetBSD 18 * Foundation, Inc. and its contributors. 19 * 4. Neither the name of The NetBSD Foundation nor the names of its 20 * contributors may be used to endorse or promote products derived 21 * from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 27 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: g2rtc.c,v 1.2 2008/01/06 10:33:24 he Exp $"); 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/device.h> 42 43 #include <dev/clock_subr.h> 44 45 #include <machine/bus.h> 46 #include <dreamcast/dev/g2/g2busvar.h> 47 48 49 #define G2RTC_REG_BASE 0x00710000 50 #define G2RTC_REG_SIZE 12 51 52 /* Offset by 20 years, 5 of them are leap */ 53 #define G2RTC_OFFSET (20 * SECYR + 5 * SECDAY) 54 55 struct g2rtc_softc { 56 struct device sc_dev; 57 58 bus_space_tag_t sc_bt; 59 bus_space_handle_t sc_bh; 60 }; 61 62 /* autoconf glue */ 63 static int g2rtc_match(struct device *, struct cfdata *, void *); 64 static void g2rtc_attach(struct device *, struct device *, void *); 65 66 CFATTACH_DECL(g2rtc, sizeof(struct g2rtc_softc), 67 g2rtc_match, g2rtc_attach, NULL, NULL); 68 69 70 /* todr(9) methods */ 71 static int g2rtc_todr_gettime(todr_chip_handle_t, volatile struct timeval *); 72 static int g2rtc_todr_settime(todr_chip_handle_t, volatile struct timeval *); 73 74 static struct todr_chip_handle g2rtc_todr_handle = { 75 .cookie = NULL, /* set on attach */ 76 .todr_gettime = g2rtc_todr_gettime, 77 .todr_settime = g2rtc_todr_settime, 78 }; 79 80 81 static inline uint32_t g2rtc_read(bus_space_tag_t, bus_space_handle_t); 82 83 84 static int 85 g2rtc_match(struct device *parent, struct cfdata *cf, void *aux) 86 { 87 static int g2rtc_matched = 0; 88 89 if (g2rtc_matched) 90 return 0; 91 92 g2rtc_matched = 1; 93 return 1; 94 } 95 96 97 static void 98 g2rtc_attach(struct device *parent, struct device *self, void *aux) 99 { 100 struct g2rtc_softc *sc = (void *)self; 101 struct g2bus_attach_args *ga = aux; 102 103 sc->sc_bt = ga->ga_memt; 104 if (bus_space_map(sc->sc_bt, G2RTC_REG_BASE, G2RTC_REG_SIZE, 0, 105 &sc->sc_bh) != 0) 106 { 107 printf(": unable to map registers\n"); 108 return; 109 } 110 printf(": time-of-day clock\n"); 111 112 g2rtc_todr_handle.cookie = sc; 113 todr_attach(&g2rtc_todr_handle); 114 } 115 116 117 static inline uint32_t 118 g2rtc_read(bus_space_tag_t bt, bus_space_handle_t bh) 119 { 120 121 return ((bus_space_read_4(bt, bh, 0) & 0xffff) << 16) 122 | (bus_space_read_4(bt, bh, 4) & 0xffff); 123 } 124 125 126 /* 127 * Get time-of-day and convert to `struct timeval'. 128 * Return 0 on success; an error number otherwise. 129 */ 130 static int 131 g2rtc_todr_gettime(todr_chip_handle_t handle, volatile struct timeval *tv) 132 { 133 struct g2rtc_softc *sc = handle->cookie; 134 uint32_t new, old; 135 int i; 136 137 for (old = 0;;) { 138 for (i = 0; i < 3; i++) { 139 new = g2rtc_read(sc->sc_bt, sc->sc_bh); 140 if (new != old) 141 break; 142 } 143 if (i < 3) 144 old = new; 145 else 146 break; 147 } 148 149 tv->tv_sec = new - G2RTC_OFFSET; 150 tv->tv_usec = 0; 151 152 return 0; 153 } 154 155 156 /* 157 * Set the time-of-day clock based on the value of the `struct timeval' arg. 158 * Return 0 on success; an error number otherwise. 159 */ 160 static int 161 g2rtc_todr_settime(todr_chip_handle_t handle, volatile struct timeval *tv) 162 { 163 struct g2rtc_softc *sc = handle->cookie; 164 uint32_t secs; 165 int i, retry; 166 167 secs = (uint32_t)tv->tv_sec + G2RTC_OFFSET; 168 169 for (retry = 0; retry < 5; retry++) { 170 171 /* Don't change the order */ 172 bus_space_write_4(sc->sc_bt, sc->sc_bh, 8, 1); 173 bus_space_write_4(sc->sc_bt, sc->sc_bh, 4, secs & 0xffff); 174 bus_space_write_4(sc->sc_bt, sc->sc_bh, 0, secs >> 16); 175 176 /* verify */ 177 for (i = 0; i < 3; i++) 178 if (g2rtc_read(sc->sc_bt, sc->sc_bh) == secs) 179 return 0; /* ok */ 180 } 181 182 return EIO; 183 184 } 185