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1 /*
2 * BCM2835 Power Management emulation
3 *
4 * Copyright (C) 2017 Marcin Chojnacki <marcinch7@gmail.com>
5 * Copyright (C) 2021 Nolan Leake <nolan@sigbus.net>
6 *
7 * This work is licensed under the terms of the GNU GPL, version 2 or later.
8 * See the COPYING file in the top-level directory.
9 */
10
11 #include "qemu/osdep.h"
12 #include "qemu/log.h"
13 #include "qemu/module.h"
14 #include "hw/misc/bcm2835_powermgt.h"
15 #include "migration/vmstate.h"
16 #include "system/runstate.h"
17
18 #define PASSWORD 0x5a000000
19 #define PASSWORD_MASK 0xff000000
20
21 #define R_RSTC 0x1c
22 #define V_RSTC_WRCFG_MASK 0x30
23 #define V_RSTC_FULL_RESET 0x20
24 #define R_RSTS 0x20
25 #define V_RSTS_POWEROFF 0x555 /* Linux uses partition 63 to indicate halt. */
26 #define R_WDOG 0x24
27 #define V_WDOG_TIME_MASK 0xfffff
28 #define WDOG_TICKS_PER_SECOND 65536
29
30 static void bcm2835_powermgt_expire(void *opaque)
31 {
32 BCM2835PowerMgtState *s = opaque;
33
34 if ((s->rsts & 0xfff) == V_RSTS_POWEROFF) {
35 qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
36 } else {
37 qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
38 }
39 }
40
41 static void bcm2835_powermgt_update_wdog(BCM2835PowerMgtState *s)
42 {
43 uint64_t timeout_ns;
44
45 if ((s->rstc & V_RSTC_WRCFG_MASK) != V_RSTC_FULL_RESET ||
46 s->wdog == 0) {
47 timer_del(s->wdog_timer);
48 return;
49 }
50
51 timeout_ns = muldiv64(s->wdog, NANOSECONDS_PER_SECOND,
52 WDOG_TICKS_PER_SECOND);
53 timer_mod(s->wdog_timer,
54 qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + timeout_ns);
55 }
56
57 static uint64_t bcm2835_powermgt_read(void *opaque, hwaddr offset,
58 unsigned size)
59 {
60 BCM2835PowerMgtState *s = (BCM2835PowerMgtState *)opaque;
61 uint32_t res = 0;
62
63 switch (offset) {
64 case R_RSTC:
65 res = s->rstc;
66 break;
67 case R_RSTS:
68 res = s->rsts;
69 break;
70 case R_WDOG:
71 res = s->wdog;
72 break;
73
74 default:
75 qemu_log_mask(LOG_UNIMP,
76 "bcm2835_powermgt_read: Unknown offset 0x%08"HWADDR_PRIx
77 "\n", offset);
78 res = 0;
79 break;
80 }
81
82 return res;
83 }
84
85 static void bcm2835_powermgt_write(void *opaque, hwaddr offset,
86 uint64_t value, unsigned size)
87 {
88 BCM2835PowerMgtState *s = (BCM2835PowerMgtState *)opaque;
89
90 if ((value & PASSWORD_MASK) != PASSWORD) {
91 qemu_log_mask(LOG_GUEST_ERROR,
92 "bcm2835_powermgt_write: Bad password 0x%"PRIx64
93 " at offset 0x%08"HWADDR_PRIx"\n",
94 value, offset);
95 return;
96 }
97
98 value = value & ~PASSWORD_MASK;
99
100 switch (offset) {
101 case R_RSTC:
102 s->rstc = value;
103 bcm2835_powermgt_update_wdog(s);
104 break;
105 case R_RSTS:
106 qemu_log_mask(LOG_UNIMP,
107 "bcm2835_powermgt_write: RSTS\n");
108 s->rsts = value;
109 break;
110 case R_WDOG:
111 s->wdog = value & V_WDOG_TIME_MASK;
112 bcm2835_powermgt_update_wdog(s);
113 break;
114
115 default:
116 qemu_log_mask(LOG_UNIMP,
117 "bcm2835_powermgt_write: Unknown offset 0x%08"HWADDR_PRIx
118 "\n", offset);
119 break;
120 }
121 }
122
123 static const MemoryRegionOps bcm2835_powermgt_ops = {
124 .read = bcm2835_powermgt_read,
125 .write = bcm2835_powermgt_write,
126 .endianness = DEVICE_NATIVE_ENDIAN,
127 .impl.min_access_size = 4,
128 .impl.max_access_size = 4,
129 };
130
131 static const VMStateDescription vmstate_bcm2835_powermgt = {
132 .name = TYPE_BCM2835_POWERMGT,
133 .version_id = 2,
134 .minimum_version_id = 2,
135 .fields = (const VMStateField[]) {
136 VMSTATE_UINT32(rstc, BCM2835PowerMgtState),
137 VMSTATE_UINT32(rsts, BCM2835PowerMgtState),
138 VMSTATE_UINT32(wdog, BCM2835PowerMgtState),
139 VMSTATE_TIMER_PTR(wdog_timer, BCM2835PowerMgtState),
140 VMSTATE_END_OF_LIST()
141 }
142 };
143
144 static void bcm2835_powermgt_init(Object *obj)
145 {
146 BCM2835PowerMgtState *s = BCM2835_POWERMGT(obj);
147
148 memory_region_init_io(&s->iomem, obj, &bcm2835_powermgt_ops, s,
149 TYPE_BCM2835_POWERMGT, 0x200);
150 sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
151 s->wdog_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
152 bcm2835_powermgt_expire, s);
153 }
154
155 static void bcm2835_powermgt_reset(DeviceState *dev)
156 {
157 BCM2835PowerMgtState *s = BCM2835_POWERMGT(dev);
158
159 /* https://elinux.org/BCM2835_registers#PM */
160 s->rstc = 0x00000102;
161 s->rsts = 0x00001000;
162 s->wdog = 0x00000000;
163 timer_del(s->wdog_timer);
164 }
165
166 static void bcm2835_powermgt_class_init(ObjectClass *klass, const void *data)
167 {
168 DeviceClass *dc = DEVICE_CLASS(klass);
169
170 device_class_set_legacy_reset(dc, bcm2835_powermgt_reset);
171 dc->vmsd = &vmstate_bcm2835_powermgt;
172 }
173
174 static const TypeInfo bcm2835_powermgt_info = {
175 .name = TYPE_BCM2835_POWERMGT,
176 .parent = TYPE_SYS_BUS_DEVICE,
177 .instance_size = sizeof(BCM2835PowerMgtState),
178 .class_init = bcm2835_powermgt_class_init,
179 .instance_init = bcm2835_powermgt_init,
180 };
181
182 static void bcm2835_powermgt_register_types(void)
183 {
184 type_register_static(&bcm2835_powermgt_info);
185 }
186
187 type_init(bcm2835_powermgt_register_types)