1 /*-
2 * Copyright (c) 2017 Andrew Turner
3 * All rights reserved.
4 *
5 * This software was developed by SRI International and the University of
6 * Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
7 * ("CTSRD"), as part of the DARPA CRASH research programme.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <sys/cdefs.h>
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/bus.h>
35 #include <sys/clock.h>
36 #include <sys/efi.h>
37 #include <sys/kernel.h>
38 #include <sys/module.h>
39
40 #include "clock_if.h"
41
42 static bool efirtc_zeroes_subseconds;
43 static struct timespec efirtc_resadj;
44
45 static const u_int us_per_s = 1000000;
46 static const u_int ns_per_s = 1000000000;
47 static const u_int ns_per_us = 1000;
48
49 static void
efirtc_identify(driver_t * driver,device_t parent)50 efirtc_identify(driver_t *driver, device_t parent)
51 {
52
53 /* Don't add the driver unless we have working runtime services. */
54 if (efi_rt_ok() != 0)
55 return;
56 if (device_find_child(parent, "efirtc", -1) != NULL)
57 return;
58 if (BUS_ADD_CHILD(parent, 0, "efirtc", -1) == NULL)
59 device_printf(parent, "add child failed\n");
60 }
61
62 static int
efirtc_probe(device_t dev)63 efirtc_probe(device_t dev)
64 {
65 struct efi_tm tm;
66 int error;
67
68 /*
69 * Check whether we can read the time. This will stop us from attaching
70 * when there is EFI Runtime support but the gettime function is
71 * unimplemented, e.g. on some builds of U-Boot.
72 */
73 if ((error = efi_get_time(&tm)) != 0) {
74 if (bootverbose)
75 device_printf(dev, "cannot read EFI realtime clock, "
76 "error %d\n", error);
77 return (error);
78 }
79 device_set_desc(dev, "EFI Realtime Clock");
80 return (BUS_PROBE_DEFAULT);
81 }
82
83 static int
efirtc_attach(device_t dev)84 efirtc_attach(device_t dev)
85 {
86 struct efi_tmcap tmcap;
87 long res;
88 int error;
89
90 bzero(&tmcap, sizeof(tmcap));
91 if ((error = efi_get_time_capabilities(&tmcap)) != 0) {
92 device_printf(dev, "cannot get EFI time capabilities");
93 return (error);
94 }
95
96 /* Translate resolution in Hz to tick length in usec. */
97 if (tmcap.tc_res == 0)
98 res = us_per_s; /* 0 is insane, assume 1 Hz. */
99 else if (tmcap.tc_res > us_per_s)
100 res = 1; /* 1us is the best we can represent */
101 else
102 res = us_per_s / tmcap.tc_res;
103
104 /* Clock rounding adjustment is 1/2 of resolution, in nsec. */
105 efirtc_resadj.tv_nsec = (res * ns_per_us) / 2;
106
107 /* Does the clock zero the subseconds when time is set? */
108 efirtc_zeroes_subseconds = tmcap.tc_stz;
109
110 /*
111 * Register. If the clock zeroes out the subseconds when it's set,
112 * schedule the SetTime calls to happen just before top-of-second.
113 */
114 clock_register_flags(dev, res, CLOCKF_SETTIME_NO_ADJ);
115 if (efirtc_zeroes_subseconds)
116 clock_schedule(dev, ns_per_s - ns_per_us);
117
118 return (0);
119 }
120
121 static int
efirtc_detach(device_t dev)122 efirtc_detach(device_t dev)
123 {
124
125 clock_unregister(dev);
126 return (0);
127 }
128
129 static int
efirtc_gettime(device_t dev,struct timespec * ts)130 efirtc_gettime(device_t dev, struct timespec *ts)
131 {
132 struct clocktime ct;
133 struct efi_tm tm;
134 int error;
135
136 error = efi_get_time(&tm);
137 if (error != 0)
138 return (error);
139
140 ct.sec = tm.tm_sec;
141 ct.min = tm.tm_min;
142 ct.hour = tm.tm_hour;
143 ct.day = tm.tm_mday;
144 ct.mon = tm.tm_mon;
145 ct.year = tm.tm_year;
146 ct.nsec = tm.tm_nsec;
147
148 clock_dbgprint_ct(dev, CLOCK_DBG_READ, &ct);
149 return (clock_ct_to_ts(&ct, ts));
150 }
151
152 static int
efirtc_settime(device_t dev,struct timespec * ts)153 efirtc_settime(device_t dev, struct timespec *ts)
154 {
155 struct clocktime ct;
156 struct efi_tm tm;
157
158 /*
159 * We request a timespec with no resolution-adjustment so that we can
160 * apply it ourselves based on whether or not the clock zeroes the
161 * sub-second part of the time when setting the time.
162 */
163 ts->tv_sec -= utc_offset();
164 if (!efirtc_zeroes_subseconds)
165 timespecadd(ts, &efirtc_resadj, ts);
166
167 clock_ts_to_ct(ts, &ct);
168 clock_dbgprint_ct(dev, CLOCK_DBG_WRITE, &ct);
169
170 bzero(&tm, sizeof(tm));
171 tm.tm_sec = ct.sec;
172 tm.tm_min = ct.min;
173 tm.tm_hour = ct.hour;
174 tm.tm_mday = ct.day;
175 tm.tm_mon = ct.mon;
176 tm.tm_year = ct.year;
177 tm.tm_nsec = ct.nsec;
178
179 return (efi_set_time(&tm));
180 }
181
182 static device_method_t efirtc_methods[] = {
183 /* Device interface */
184 DEVMETHOD(device_identify, efirtc_identify),
185 DEVMETHOD(device_probe, efirtc_probe),
186 DEVMETHOD(device_attach, efirtc_attach),
187 DEVMETHOD(device_detach, efirtc_detach),
188
189 /* Clock interface */
190 DEVMETHOD(clock_gettime, efirtc_gettime),
191 DEVMETHOD(clock_settime, efirtc_settime),
192
193 DEVMETHOD_END
194 };
195
196 static driver_t efirtc_driver = {
197 "efirtc",
198 efirtc_methods,
199 0
200 };
201
202 DRIVER_MODULE(efirtc, nexus, efirtc_driver, 0, 0);
203 MODULE_VERSION(efirtc, 1);
204 MODULE_DEPEND(efirtc, efirt, 1, 1, 1);
205