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gfrtc.c revision 1.2 
      1 /*	$NetBSD: gfrtc.c,v 1.2 2023/12/31 22:06:41 thorpej Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2023 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Nick Hudson.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: gfrtc.c,v 1.2 2023/12/31 22:06:41 thorpej Exp $");
     34 
     35 #include <sys/param.h>
     36 
     37 #include <sys/bus.h>
     38 #include <sys/device.h>
     39 
     40 #include <dev/goldfish/gfrtcvar.h>
     41 
     42 /*
     43  * https://android.googlesource.com/platform/external/qemu/+/master/docs/GOLDFISH-VIRTUAL-HARDWARE.TXT
     44  */
     45 
     46 #define	GOLDFISH_RTC_READ(sc, reg) \
     47 	bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg))
     48 #define	GOLDFISH_RTC_WRITE(sc, reg, val) \
     49 	bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))
     50 
     51 
     52 #define	GOLDFISH_RTC_TIME_LOW	0x00
     53 #define	GOLDFISH_RTC_TIME_HIGH	0x04
     54 
     55 
     56 static int
     57 gfrtc_gettime(struct todr_chip_handle *ch, struct timeval *tv)
     58 {
     59 	struct gfrtc_softc *sc = ch->cookie;
     60 	const uint64_t lo = GOLDFISH_RTC_READ(sc, GOLDFISH_RTC_TIME_LOW);
     61 	const uint64_t hi = GOLDFISH_RTC_READ(sc, GOLDFISH_RTC_TIME_HIGH);
     62 
     63 	uint64_t nsec = (hi << 32) | lo;
     64 
     65 	tv->tv_sec = nsec / 1000000000;
     66 	tv->tv_usec = (nsec - tv->tv_sec) / 1000;	// Always 0?
     67 
     68 	return 0;
     69 }
     70 
     71 static int
     72 gfrtc_settime(struct todr_chip_handle *ch, struct timeval *tv)
     73 {
     74 	struct gfrtc_softc *sc = ch->cookie;
     75 
     76 	uint64_t nsec = (tv->tv_sec * 1000000 + tv->tv_usec) * 1000;
     77 	uint32_t hi = nsec >> 32;
     78 	uint32_t lo = nsec;
     79 
     80 	GOLDFISH_RTC_WRITE(sc, GOLDFISH_RTC_TIME_HIGH, hi);
     81 	GOLDFISH_RTC_WRITE(sc, GOLDFISH_RTC_TIME_LOW, lo);
     82 
     83 	return 0;
     84 }
     85 
     86 
     87 void
     88 gfrtc_attach(struct gfrtc_softc * const sc)
     89 {
     90 	sc->sc_todr.cookie = sc;
     91 	sc->sc_todr.todr_gettime = gfrtc_gettime;
     92 	sc->sc_todr.todr_settime = gfrtc_settime;
     93 	sc->sc_todr.todr_setwen = NULL;
     94 
     95 	todr_attach(&sc->sc_todr);
     96 }
     97