gfrtc.c revision 1.1 
1/*	$NetBSD: gfrtc.c,v 1.1 2023/12/29 23:31:44 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 1.1 2023/12/29 23:31:44 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
56static int
57gfrtc_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
71static int
72gfrtc_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_HIGH, lo);
82
83	return 0;
84}
85
86
87void
88gfrtc_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