1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2020 Jessica Clarke <jrtc27@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 /*
29 * Driver for simple syscon poweroff and reset devices. The device tree
30 * specifications are fully described at:
31 *
32 * https://www.kernel.org/doc/Documentation/devicetree/bindings/power/reset/syscon-poweroff.txt
33 * https://www.kernel.org/doc/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt
34 */
35
36 #include <sys/param.h>
37 #include <sys/bus.h>
38 #include <sys/types.h>
39 #include <sys/eventhandler.h>
40 #include <sys/kernel.h>
41 #include <sys/module.h>
42 #include <sys/reboot.h>
43
44 #include <machine/bus.h>
45
46 #include <dev/ofw/ofw_bus.h>
47 #include <dev/ofw/ofw_bus_subr.h>
48 #include <dev/ofw/openfirm.h>
49
50 #include "syscon_if.h"
51 #include "syscon.h"
52
53 struct syscon_power_softc {
54 struct syscon *regmap;
55 uint32_t offset;
56 uint32_t value;
57 uint32_t mask;
58 bool reboot;
59 eventhandler_tag shutdown_tag;
60 };
61
62 static void
syscon_power_shutdown_final(device_t dev,int howto)63 syscon_power_shutdown_final(device_t dev, int howto)
64 {
65 struct syscon_power_softc *sc;
66 bool write;
67
68 sc = device_get_softc(dev);
69 if (sc->reboot)
70 write = (howto & RB_HALT) == 0;
71 else
72 write = (howto & RB_POWEROFF) != 0;
73
74 if (write)
75 SYSCON_MODIFY_4(sc->regmap, sc->offset, sc->mask,
76 sc->value & sc->mask);
77 }
78
79 static int
syscon_power_probe(device_t dev)80 syscon_power_probe(device_t dev)
81 {
82
83 if (!ofw_bus_status_okay(dev))
84 return (ENXIO);
85
86 if (ofw_bus_is_compatible(dev, "syscon-poweroff")) {
87 device_set_desc(dev, "Syscon poweroff");
88 return (BUS_PROBE_DEFAULT);
89 } else if (ofw_bus_is_compatible(dev, "syscon-reboot")) {
90 device_set_desc(dev, "Syscon reboot");
91 return (BUS_PROBE_DEFAULT);
92 }
93
94 return (ENXIO);
95 }
96
97 static int
syscon_power_attach(device_t dev)98 syscon_power_attach(device_t dev)
99 {
100 struct syscon_power_softc *sc;
101 phandle_t node;
102 int error, len;
103 bool has_mask;
104
105 sc = device_get_softc(dev);
106 node = ofw_bus_get_node(dev);
107
108 if (!OF_hasprop(node, "regmap")) {
109 device_printf(dev, "could not find regmap\n");
110 return (ENXIO);
111 }
112
113 error = syscon_get_by_ofw_property(dev, node, "regmap", &sc->regmap);
114 if (error != 0) {
115 device_printf(dev, "could not get syscon\n");
116 return (ENXIO);
117 }
118
119 len = OF_getproplen(node, "offset");
120 if (len != 4) {
121 device_printf(dev, "could not get offset\n");
122 return (ENXIO);
123 }
124
125 OF_getencprop(node, "offset", &sc->offset, sizeof(sc->offset));
126
127 /* Optional mask */
128 has_mask = OF_hasprop(node, "mask");
129 if (has_mask) {
130 len = OF_getproplen(node, "mask");
131 if (len != 4) {
132 device_printf(dev, "cannot handle mask\n");
133 return (ENXIO);
134 }
135
136 OF_getencprop(node, "mask", &sc->mask, sizeof(sc->mask));
137 } else {
138 sc->mask = 0xffffffff;
139 }
140
141 /*
142 * From the device tree specification:
143 *
144 * Legacy usage: If a node doesn't contain a value property but
145 * contains a mask property, the mask property is used as the value.
146 */
147 if (!OF_hasprop(node, "value")) {
148 if (!has_mask) {
149 device_printf(dev, "must have a value or a mask\n");
150 return (ENXIO);
151 }
152
153 sc->value = sc->mask;
154 } else {
155 len = OF_getproplen(node, "value");
156 if (len != 4) {
157 device_printf(dev, "cannot handle value\n");
158 return (ENXIO);
159 }
160
161 OF_getencprop(node, "value", &sc->value, sizeof(sc->value));
162 }
163
164 /* Handle reboot after shutdown_panic. */
165 sc->reboot = ofw_bus_is_compatible(dev, "syscon-reboot");
166 sc->shutdown_tag = EVENTHANDLER_REGISTER(shutdown_final,
167 syscon_power_shutdown_final, dev,
168 sc->reboot ? SHUTDOWN_PRI_LAST + 150 : SHUTDOWN_PRI_LAST);
169
170 return (0);
171 }
172
173 static int
syscon_power_detach(device_t dev)174 syscon_power_detach(device_t dev)
175 {
176 struct syscon_power_softc *sc;
177
178 sc = device_get_softc(dev);
179 EVENTHANDLER_DEREGISTER(shutdown_final, sc->shutdown_tag);
180
181 return (0);
182 }
183
184 static device_method_t syscon_power_methods[] = {
185 DEVMETHOD(device_probe, syscon_power_probe),
186 DEVMETHOD(device_attach, syscon_power_attach),
187 DEVMETHOD(device_detach, syscon_power_detach),
188
189 DEVMETHOD_END
190 };
191
192 DEFINE_CLASS_0(syscon_power, syscon_power_driver, syscon_power_methods,
193 sizeof(struct syscon_power_softc));
194
195 DRIVER_MODULE(syscon_power, simplebus, syscon_power_driver, NULL, NULL);
196