hw/misc/bcm2835_powermgt.c

   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 = (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 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)