hw/misc/bcm2835_thermal.c

   1 /*
   2  * BCM2835 dummy thermal sensor
   3  *
   4  * Copyright (C) 2019 Philippe Mathieu-Daudé <f4bug@amsat.org>
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-or-later
   7  */
   8
   9 #include "qemu/osdep.h"
  10 #include "qemu/log.h"
  11 #include "qapi/error.h"
  12 #include "hw/misc/bcm2835_thermal.h"
  13 #include "hw/registerfields.h"
  14 #include "migration/vmstate.h"
  15
  16 REG32(CTL, 0)
  17 FIELD(CTL, POWER_DOWN, 0, 1)
  18 FIELD(CTL, RESET, 1, 1)
  19 FIELD(CTL, BANDGAP_CTRL, 2, 3)
  20 FIELD(CTL, INTERRUPT_ENABLE, 5, 1)
  21 FIELD(CTL, DIRECT, 6, 1)
  22 FIELD(CTL, INTERRUPT_CLEAR, 7, 1)
  23 FIELD(CTL, HOLD, 8, 10)
  24 FIELD(CTL, RESET_DELAY, 18, 8)
  25 FIELD(CTL, REGULATOR_ENABLE, 26, 1)
  26
  27 REG32(STAT, 4)
  28 FIELD(STAT, DATA, 0, 10)
  29 FIELD(STAT, VALID, 10, 1)
  30 FIELD(STAT, INTERRUPT, 11, 1)
  31
  32 #define THERMAL_OFFSET_C 412
  33 #define THERMAL_COEFF  (-0.538f)
  34
  35 static uint16_t bcm2835_thermal_temp2adc(int temp_C)
  36 {
  37     return (temp_C - THERMAL_OFFSET_C) / THERMAL_COEFF;
  38 }
  39
  40 static uint64_t bcm2835_thermal_read(void *opaque, hwaddr addr, unsigned size)
  41 {
  42     Bcm2835ThermalState *s = BCM2835_THERMAL(opaque);
  43     uint32_t val = 0;
  44
  45     switch (addr) {
  46     case A_CTL:
  47         val = s->ctl;
  48         break;
  49     case A_STAT:
  50         /* Temperature is constantly 25°C. */
  51         val = FIELD_DP32(bcm2835_thermal_temp2adc(25), STAT, VALID, true);
  52         break;
  53     default:
  54         /* MemoryRegionOps are aligned, so this can not happen. */
  55         g_assert_not_reached();
  56     }
  57     return val;
  58 }
  59
  60 static void bcm2835_thermal_write(void *opaque, hwaddr addr,
  61                                   uint64_t value, unsigned size)
  62 {
  63     Bcm2835ThermalState *s = BCM2835_THERMAL(opaque);
  64
  65     switch (addr) {
  66     case A_CTL:
  67         s->ctl = value;
  68         break;
  69     case A_STAT:
  70         qemu_log_mask(LOG_GUEST_ERROR, "%s: write 0x%" PRIx64
  71                                        " to 0x%" HWADDR_PRIx "\n",
  72                        __func__, value, addr);
  73         break;
  74     default:
  75         /* MemoryRegionOps are aligned, so this can not happen. */
  76         g_assert_not_reached();
  77     }
  78 }
  79
  80 static const MemoryRegionOps bcm2835_thermal_ops = {
  81     .read = bcm2835_thermal_read,
  82     .write = bcm2835_thermal_write,
  83     .impl.max_access_size = 4,
  84     .valid.min_access_size = 4,
  85     .endianness = DEVICE_NATIVE_ENDIAN,
  86 };
  87
  88 static void bcm2835_thermal_reset(DeviceState *dev)
  89 {
  90     Bcm2835ThermalState *s = BCM2835_THERMAL(dev);
  91
  92     s->ctl = 0;
  93 }
  94
  95 static void bcm2835_thermal_realize(DeviceState *dev, Error **errp)
  96 {
  97     Bcm2835ThermalState *s = BCM2835_THERMAL(dev);
  98
  99     memory_region_init_io(&s->iomem, OBJECT(s), &bcm2835_thermal_ops,
 100                           s, TYPE_BCM2835_THERMAL, 8);
 101     sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
 102 }
 103
 104 static const VMStateDescription bcm2835_thermal_vmstate = {
 105     .name = "bcm2835_thermal",
 106     .version_id = 1,
 107     .minimum_version_id = 1,
 108     .fields = (VMStateField[]) {
 109         VMSTATE_UINT32(ctl, Bcm2835ThermalState),
 110         VMSTATE_END_OF_LIST()
 111     }
 112 };
 113
 114 static void bcm2835_thermal_class_init(ObjectClass *klass, void *data)
 115 {
 116     DeviceClass *dc = DEVICE_CLASS(klass);
 117
 118     dc->realize = bcm2835_thermal_realize;
 119     dc->reset = bcm2835_thermal_reset;
 120     dc->vmsd = &bcm2835_thermal_vmstate;
 121 }
 122
 123 static const TypeInfo bcm2835_thermal_info = {
 124     .name = TYPE_BCM2835_THERMAL,
 125     .parent = TYPE_SYS_BUS_DEVICE,
 126     .instance_size = sizeof(Bcm2835ThermalState),
 127     .class_init = bcm2835_thermal_class_init,
 128 };
 129
 130 static void bcm2835_thermal_register_types(void)
 131 {
 132     type_register_static(&bcm2835_thermal_info);
 133 }
 134
 135 type_init(bcm2835_thermal_register_types)