1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2020 Jessica Clarke <[email protected]>
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/cdefs.h>
37 #include <sys/param.h>
38 #include <sys/bus.h>
39 #include <sys/types.h>
40 #include <sys/eventhandler.h>
41 #include <sys/kernel.h>
42 #include <sys/module.h>
43 #include <sys/reboot.h>
44
45 #include <machine/bus.h>
46
47 #include <dev/ofw/ofw_bus.h>
48 #include <dev/ofw/ofw_bus_subr.h>
49 #include <dev/ofw/openfirm.h>
50
51 #include "syscon_if.h"
52 #include "syscon.h"
53
54 struct syscon_power_softc {
55 struct syscon *regmap;
56 uint32_t offset;
57 uint32_t value;
58 uint32_t mask;
59 bool reboot;
60 eventhandler_tag shutdown_tag;
61 };
62
63 static void
syscon_power_shutdown_final(device_t dev,int howto)64 syscon_power_shutdown_final(device_t dev, int howto)
65 {
66 struct syscon_power_softc *sc;
67 bool write;
68
69 sc = device_get_softc(dev);
70 if (sc->reboot)
71 write = (howto & RB_HALT) == 0;
72 else
73 write = (howto & RB_POWEROFF) != 0;
74
75 if (write)
76 SYSCON_MODIFY_4(sc->regmap, sc->offset, sc->mask,
77 sc->value & sc->mask);
78 }
79
80 static int
syscon_power_probe(device_t dev)81 syscon_power_probe(device_t dev)
82 {
83
84 if (!ofw_bus_status_okay(dev))
85 return (ENXIO);
86
87 if (ofw_bus_is_compatible(dev, "syscon-poweroff")) {
88 device_set_desc(dev, "Syscon poweroff");
89 return (BUS_PROBE_DEFAULT);
90 } else if (ofw_bus_is_compatible(dev, "syscon-reboot")) {
91 device_set_desc(dev, "Syscon reboot");
92 return (BUS_PROBE_DEFAULT);
93 }
94
95 return (ENXIO);
96 }
97
98 static int
syscon_power_attach(device_t dev)99 syscon_power_attach(device_t dev)
100 {
101 struct syscon_power_softc *sc;
102 phandle_t node;
103 int error, len;
104 bool has_mask;
105
106 sc = device_get_softc(dev);
107 node = ofw_bus_get_node(dev);
108
109 if (!OF_hasprop(node, "regmap")) {
110 device_printf(dev, "could not find regmap\n");
111 return (ENXIO);
112 }
113
114 error = syscon_get_by_ofw_property(dev, node, "regmap", &sc->regmap);
115 if (error != 0) {
116 device_printf(dev, "could not get syscon\n");
117 return (ENXIO);
118 }
119
120 len = OF_getproplen(node, "offset");
121 if (len != 4) {
122 device_printf(dev, "could not get offset\n");
123 return (ENXIO);
124 }
125
126 OF_getencprop(node, "offset", &sc->offset, sizeof(sc->offset));
127
128 /* Optional mask */
129 has_mask = OF_hasprop(node, "mask");
130 if (has_mask) {
131 len = OF_getproplen(node, "mask");
132 if (len != 4) {
133 device_printf(dev, "cannot handle mask\n");
134 return (ENXIO);
135 }
136
137 OF_getencprop(node, "mask", &sc->mask, sizeof(sc->mask));
138 } else {
139 sc->mask = 0xffffffff;
140 }
141
142 /*
143 * From the device tree specification:
144 *
145 * Legacy usage: If a node doesn't contain a value property but
146 * contains a mask property, the mask property is used as the value.
147 */
148 if (!OF_hasprop(node, "value")) {
149 if (!has_mask) {
150 device_printf(dev, "must have a value or a mask\n");
151 return (ENXIO);
152 }
153
154 sc->value = sc->mask;
155 } else {
156 len = OF_getproplen(node, "value");
157 if (len != 4) {
158 device_printf(dev, "cannot handle value\n");
159 return (ENXIO);
160 }
161
162 OF_getencprop(node, "value", &sc->value, sizeof(sc->value));
163 }
164
165 /* Handle reboot after shutdown_panic. */
166 sc->reboot = ofw_bus_is_compatible(dev, "syscon-reboot");
167 sc->shutdown_tag = EVENTHANDLER_REGISTER(shutdown_final,
168 syscon_power_shutdown_final, dev,
169 sc->reboot ? SHUTDOWN_PRI_LAST + 150 : SHUTDOWN_PRI_LAST);
170
171 return (0);
172 }
173
174 static int
syscon_power_detach(device_t dev)175 syscon_power_detach(device_t dev)
176 {
177 struct syscon_power_softc *sc;
178
179 sc = device_get_softc(dev);
180 EVENTHANDLER_DEREGISTER(shutdown_final, sc->shutdown_tag);
181
182 return (0);
183 }
184
185 static device_method_t syscon_power_methods[] = {
186 DEVMETHOD(device_probe, syscon_power_probe),
187 DEVMETHOD(device_attach, syscon_power_attach),
188 DEVMETHOD(device_detach, syscon_power_detach),
189
190 DEVMETHOD_END
191 };
192
193 DEFINE_CLASS_0(syscon_power, syscon_power_driver, syscon_power_methods,
194 sizeof(struct syscon_power_softc));
195
196 DRIVER_MODULE(syscon_power, simplebus, syscon_power_driver, NULL, NULL);
197