xref: /qemu/hw/misc/bcm2835_powermgt.c (revision 2abf0da2) 
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 "sysemu/runstate.h"
17 
18 #define PASSWORD 0x5a000000
19 #define PASSWORD_MASK 0xff000000
20 
21 #define R_RSTC 0x1c
22 #define V_RSTC_RESET 0x20
23 #define R_RSTS 0x20
24 #define V_RSTS_POWEROFF 0x555 /* Linux uses partition 63 to indicate halt. */
25 #define R_WDOG 0x24
26 
27 static uint64_t bcm2835_powermgt_read(void *opaque, hwaddr offset,
28                                       unsigned size)
29 {
30     BCM2835PowerMgtState *s = (BCM2835PowerMgtState *)opaque;
31     uint32_t res = 0;
32 
33     switch (offset) {
34     case R_RSTC:
35         res = s->rstc;
36         break;
37     case R_RSTS:
38         res = s->rsts;
39         break;
40     case R_WDOG:
41         res = s->wdog;
42         break;
43 
44     default:
45         qemu_log_mask(LOG_UNIMP,
46                       "bcm2835_powermgt_read: Unknown offset 0x%08"HWADDR_PRIx
47                       "\n", offset);
48         res = 0;
49         break;
50     }
51 
52     return res;
53 }
54 
55 static void bcm2835_powermgt_write(void *opaque, hwaddr offset,
56                                    uint64_t value, unsigned size)
57 {
58     BCM2835PowerMgtState *s = (BCM2835PowerMgtState *)opaque;
59 
60     if ((value & PASSWORD_MASK) != PASSWORD) {
61         qemu_log_mask(LOG_GUEST_ERROR,
62                       "bcm2835_powermgt_write: Bad password 0x%"PRIx64
63                       " at offset 0x%08"HWADDR_PRIx"\n",
64                       value, offset);
65         return;
66     }
67 
68     value = value & ~PASSWORD_MASK;
69 
70     switch (offset) {
71     case R_RSTC:
72         s->rstc = value;
73         if (value & V_RSTC_RESET) {
74             if ((s->rsts & 0xfff) == V_RSTS_POWEROFF) {
75                 qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
76             } else {
77                 qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
78             }
79         }
80         break;
81     case R_RSTS:
82         qemu_log_mask(LOG_UNIMP,
83                       "bcm2835_powermgt_write: RSTS\n");
84         s->rsts = value;
85         break;
86     case R_WDOG:
87         qemu_log_mask(LOG_UNIMP,
88                       "bcm2835_powermgt_write: WDOG\n");
89         s->wdog = value;
90         break;
91 
92     default:
93         qemu_log_mask(LOG_UNIMP,
94                       "bcm2835_powermgt_write: Unknown offset 0x%08"HWADDR_PRIx
95                       "\n", offset);
96         break;
97     }
98 }
99 
100 static const MemoryRegionOps bcm2835_powermgt_ops = {
101     .read = bcm2835_powermgt_read,
102     .write = bcm2835_powermgt_write,
103     .endianness = DEVICE_NATIVE_ENDIAN,
104     .impl.min_access_size = 4,
105     .impl.max_access_size = 4,
106 };
107 
108 static const VMStateDescription vmstate_bcm2835_powermgt = {
109     .name = TYPE_BCM2835_POWERMGT,
110     .version_id = 1,
111     .minimum_version_id = 1,
112     .fields = (const VMStateField[]) {
113         VMSTATE_UINT32(rstc, BCM2835PowerMgtState),
114         VMSTATE_UINT32(rsts, BCM2835PowerMgtState),
115         VMSTATE_UINT32(wdog, BCM2835PowerMgtState),
116         VMSTATE_END_OF_LIST()
117     }
118 };
119 
120 static void bcm2835_powermgt_init(Object *obj)
121 {
122     BCM2835PowerMgtState *s = BCM2835_POWERMGT(obj);
123 
124     memory_region_init_io(&s->iomem, obj, &bcm2835_powermgt_ops, s,
125                           TYPE_BCM2835_POWERMGT, 0x200);
126     sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
127 }
128 
129 static void bcm2835_powermgt_reset(DeviceState *dev)
130 {
131     BCM2835PowerMgtState *s = BCM2835_POWERMGT(dev);
132 
133     /* https://elinux.org/BCM2835_registers#PM */
134     s->rstc = 0x00000102;
135     s->rsts = 0x00001000;
136     s->wdog = 0x00000000;
137 }
138 
139 static void bcm2835_powermgt_class_init(ObjectClass *klass, void *data)
140 {
141     DeviceClass *dc = DEVICE_CLASS(klass);
142 
143     dc->reset = bcm2835_powermgt_reset;
144     dc->vmsd = &vmstate_bcm2835_powermgt;
145 }
146 
147 static const TypeInfo bcm2835_powermgt_info = {
148     .name          = TYPE_BCM2835_POWERMGT,
149     .parent        = TYPE_SYS_BUS_DEVICE,
150     .instance_size = sizeof(BCM2835PowerMgtState),
151     .class_init    = bcm2835_powermgt_class_init,
152     .instance_init = bcm2835_powermgt_init,
153 };
154 
155 static void bcm2835_powermgt_register_types(void)
156 {
157     type_register_static(&bcm2835_powermgt_info);
158 }
159 
160 type_init(bcm2835_powermgt_register_types)
161