xref: /openbmc/qemu/hw/misc/bcm2835_powermgt.c (revision 28ae3179fc52d2e4d870b635c4a412aab99759e7)
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  
bcm2835_powermgt_read(void * opaque,hwaddr offset,unsigned size)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  
bcm2835_powermgt_write(void * opaque,hwaddr offset,uint64_t value,unsigned size)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  
bcm2835_powermgt_init(Object * obj)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  
bcm2835_powermgt_reset(DeviceState * dev)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  
bcm2835_powermgt_class_init(ObjectClass * klass,void * data)139  static void bcm2835_powermgt_class_init(ObjectClass *klass, void *data)
140  {
141      DeviceClass *dc = DEVICE_CLASS(klass);
142  
143      device_class_set_legacy_reset(dc, 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  
bcm2835_powermgt_register_types(void)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