1 /* $NetBSD: g2rtc.c,v 1.8 2016/10/09 14:41:47 christos 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 *
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: g2rtc.c,v 1.8 2016/10/09 14:41:47 christos Exp $");
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/device.h>
35 #include <sys/bus.h>
36
37 #include <dev/clock_subr.h>
38
39 #include <dreamcast/dev/g2/g2busvar.h>
40
41
42 #define G2RTC_REG_BASE 0x00710000
43 #define G2RTC_REG_SIZE 12
44
45 /* Offset by 20 years, 5 of them are leap */
46 #define G2RTC_OFFSET (20 * SECS_PER_COMMON_YEAR + 5 * SECS_PER_DAY)
47
48 struct g2rtc_softc {
49 device_t sc_dev;
50
51 bus_space_tag_t sc_bt;
52 bus_space_handle_t sc_bh;
53 struct todr_chip_handle sc_tch;
54 };
55
56 /* autoconf glue */
57 static int g2rtc_match(device_t, cfdata_t, void *);
58 static void g2rtc_attach(device_t, device_t, void *);
59
60 CFATTACH_DECL_NEW(g2rtc, sizeof(struct g2rtc_softc),
61 g2rtc_match, g2rtc_attach, NULL, NULL);
62
63
64 /* todr(9) methods */
65 static int g2rtc_todr_gettime(todr_chip_handle_t, struct timeval *);
66 static int g2rtc_todr_settime(todr_chip_handle_t, struct timeval *);
67
68 static inline uint32_t g2rtc_read(bus_space_tag_t, bus_space_handle_t);
69
70
71 static int
g2rtc_match(device_t parent,cfdata_t cf,void * aux)72 g2rtc_match(device_t parent, cfdata_t cf, void *aux)
73 {
74 static int g2rtc_matched = 0;
75
76 if (g2rtc_matched)
77 return 0;
78
79 g2rtc_matched = 1;
80 return 1;
81 }
82
83
84 static void
g2rtc_attach(device_t parent,device_t self,void * aux)85 g2rtc_attach(device_t parent, device_t self, void *aux)
86 {
87 struct g2rtc_softc *sc = device_private(self);
88 struct g2bus_attach_args *ga = aux;
89 todr_chip_handle_t tch;
90
91 sc->sc_dev = self;
92 sc->sc_bt = ga->ga_memt;
93 if (bus_space_map(sc->sc_bt, G2RTC_REG_BASE, G2RTC_REG_SIZE, 0,
94 &sc->sc_bh) != 0) {
95 printf(": unable to map registers\n");
96 return;
97 }
98 printf(": time-of-day clock\n");
99
100 tch = &sc->sc_tch;
101 tch->cookie = sc;
102 tch->todr_gettime = g2rtc_todr_gettime;
103 tch->todr_settime = g2rtc_todr_settime;
104 todr_attach(tch);
105 }
106
107
108 static inline uint32_t
g2rtc_read(bus_space_tag_t bt,bus_space_handle_t bh)109 g2rtc_read(bus_space_tag_t bt, bus_space_handle_t bh)
110 {
111
112 return ((bus_space_read_4(bt, bh, 0) & 0xffff) << 16)
113 | (bus_space_read_4(bt, bh, 4) & 0xffff);
114 }
115
116
117 /*
118 * Get time-of-day and convert to `struct timeval'.
119 * Return 0 on success; an error number otherwise.
120 */
121 static int
g2rtc_todr_gettime(todr_chip_handle_t handle,struct timeval * tv)122 g2rtc_todr_gettime(todr_chip_handle_t handle, struct timeval *tv)
123 {
124 struct g2rtc_softc *sc = handle->cookie;
125 uint32_t new, old;
126 int i;
127
128 for (old = 0;;) {
129 for (i = 0; i < 3; i++) {
130 new = g2rtc_read(sc->sc_bt, sc->sc_bh);
131 if (new != old)
132 break;
133 }
134 if (i < 3)
135 old = new;
136 else
137 break;
138 }
139
140 tv->tv_sec = new - G2RTC_OFFSET;
141 tv->tv_usec = 0;
142
143 return 0;
144 }
145
146
147 /*
148 * Set the time-of-day clock based on the value of the `struct timeval' arg.
149 * Return 0 on success; an error number otherwise.
150 */
151 static int
g2rtc_todr_settime(todr_chip_handle_t handle,struct timeval * tv)152 g2rtc_todr_settime(todr_chip_handle_t handle, struct timeval *tv)
153 {
154 struct g2rtc_softc *sc = handle->cookie;
155 uint32_t secs;
156 int i, retry;
157
158 secs = (uint32_t)tv->tv_sec + G2RTC_OFFSET;
159
160 for (retry = 0; retry < 5; retry++) {
161
162 /* Don't change the order */
163 bus_space_write_4(sc->sc_bt, sc->sc_bh, 8, 1);
164 bus_space_write_4(sc->sc_bt, sc->sc_bh, 4, secs & 0xffff);
165 bus_space_write_4(sc->sc_bt, sc->sc_bh, 0, secs >> 16);
166
167 /* verify */
168 for (i = 0; i < 3; i++)
169 if (g2rtc_read(sc->sc_bt, sc->sc_bh) == secs)
170 return 0; /* ok */
171 }
172
173 return EIO;
174 }
175