gfrtc_fdt.c revision 1.1 
1/*	$NetBSD: gfrtc_fdt.c,v 1.1 2023/05/08 07:51:44 skrll 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_fdt.c,v 1.1 2023/05/08 07:51:44 skrll Exp $");
34
35#include <sys/param.h>
36
37#include <sys/bus.h>
38#include <sys/device.h>
39
40#include <dev/fdt/fdtvar.h>
41
42/*
43 * https://android.googlesource.com/platform/external/qemu/+/master/docs/GOLDFISH-VIRTUAL-HARDWARE.TXT
44 */
45
46static const struct device_compatible_entry compat_data[] = {
47	{ .compat = "google,goldfish-rtc" },
48	DEVICE_COMPAT_EOL
49};
50
51struct gfrtc_fdt_softc {
52	device_t sc_dev;
53	bus_space_tag_t sc_bst;
54	bus_space_handle_t sc_bsh;
55
56	struct todr_chip_handle	sc_todr;
57};
58
59#define	GOLDFISH_RTC_READ(sc, reg) \
60	bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg))
61#define	GOLDFISH_RTC_WRITE(sc, reg, val) \
62	bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))
63
64
65#define	GOLDFISH_RTC_TIME_LOW	0x00
66#define	GOLDFISH_RTC_TIME_HIGH	0x04
67
68
69static int
70gfrtc_gettime(struct todr_chip_handle *ch, struct timeval *tv)
71{
72	struct gfrtc_fdt_softc *sc = ch->cookie;
73	const uint64_t lo = GOLDFISH_RTC_READ(sc, GOLDFISH_RTC_TIME_LOW);
74	const uint64_t hi = GOLDFISH_RTC_READ(sc, GOLDFISH_RTC_TIME_HIGH);
75
76	uint64_t nsec = (hi << 32) | lo;
77
78	tv->tv_sec = nsec / 1000000000;
79	tv->tv_usec = (nsec - tv->tv_sec) / 1000;	// Always 0?
80
81	return 0;
82}
83
84static int
85gfrtc_settime(struct todr_chip_handle *ch, struct timeval *tv)
86{
87	struct gfrtc_fdt_softc *sc = ch->cookie;
88
89	uint64_t nsec = (tv->tv_sec * 1000000 + tv->tv_usec) * 1000;
90	uint32_t hi = nsec >> 32;
91	uint32_t lo = nsec;
92
93	GOLDFISH_RTC_WRITE(sc, GOLDFISH_RTC_TIME_HIGH, hi);
94	GOLDFISH_RTC_WRITE(sc, GOLDFISH_RTC_TIME_HIGH, lo);
95
96	return 0;
97}
98
99
100static int
101gfrtc_fdt_match(device_t parent, cfdata_t cf, void *aux)
102{
103	struct fdt_attach_args * const faa = aux;
104
105	return of_compatible_match(faa->faa_phandle, compat_data);
106}
107
108static void
109gfrtc_fdt_attach(device_t parent, device_t self, void *aux)
110{
111	struct gfrtc_fdt_softc * const sc = device_private(self);
112	struct fdt_attach_args * const faa = aux;
113	const int phandle = faa->faa_phandle;
114	bus_addr_t addr;
115	bus_size_t size;
116
117	if (fdtbus_get_reg(phandle, 0, &addr, &size) != 0) {
118		aprint_error(": couldn't get registers\n");
119		return;
120	}
121
122	sc->sc_dev = self;
123	sc->sc_bst = faa->faa_bst;
124	if (bus_space_map(sc->sc_bst, addr, size, 0, &sc->sc_bsh) != 0) {
125		aprint_error(": couldn't map registers\n");
126		return;
127	}
128
129	aprint_naive("\n");
130	aprint_normal(": Google Goldfish RTC\n");
131
132	sc->sc_todr.cookie = sc;
133	sc->sc_todr.todr_gettime = gfrtc_gettime;
134	sc->sc_todr.todr_settime = gfrtc_settime;
135	sc->sc_todr.todr_setwen = NULL;
136
137	todr_attach(&sc->sc_todr);
138}
139
140CFATTACH_DECL_NEW(gfrtc_fdt, sizeof(struct gfrtc_fdt_softc),
141	gfrtc_fdt_match, gfrtc_fdt_attach, NULL, NULL);
142