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bcm2835_powermgt.c (4424B)

      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 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)