xref: /qemu/hw/misc/bcm2835_thermal.c (revision 06b40d250ecfa1633209c2e431a7a38acfd03a98)
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  
bcm2835_thermal_temp2adc(int temp_C)35  static uint16_t bcm2835_thermal_temp2adc(int temp_C)
36  {
37      return (temp_C - THERMAL_OFFSET_C) / THERMAL_COEFF;
38  }
39  
bcm2835_thermal_read(void * opaque,hwaddr addr,unsigned size)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  
bcm2835_thermal_write(void * opaque,hwaddr addr,uint64_t value,unsigned size)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.min_access_size = 4,
84      .impl.max_access_size = 4,
85      .valid.min_access_size = 4,
86      .valid.max_access_size = 4,
87      .endianness = DEVICE_NATIVE_ENDIAN,
88  };
89  
bcm2835_thermal_reset(DeviceState * dev)90  static void bcm2835_thermal_reset(DeviceState *dev)
91  {
92      Bcm2835ThermalState *s = BCM2835_THERMAL(dev);
93  
94      s->ctl = 0;
95  }
96  
bcm2835_thermal_realize(DeviceState * dev,Error ** errp)97  static void bcm2835_thermal_realize(DeviceState *dev, Error **errp)
98  {
99      Bcm2835ThermalState *s = BCM2835_THERMAL(dev);
100  
101      memory_region_init_io(&s->iomem, OBJECT(s), &bcm2835_thermal_ops,
102                            s, TYPE_BCM2835_THERMAL, 8);
103      sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
104  }
105  
106  static const VMStateDescription bcm2835_thermal_vmstate = {
107      .name = "bcm2835_thermal",
108      .version_id = 1,
109      .minimum_version_id = 1,
110      .fields = (const VMStateField[]) {
111          VMSTATE_UINT32(ctl, Bcm2835ThermalState),
112          VMSTATE_END_OF_LIST()
113      }
114  };
115  
bcm2835_thermal_class_init(ObjectClass * klass,const void * data)116  static void bcm2835_thermal_class_init(ObjectClass *klass, const void *data)
117  {
118      DeviceClass *dc = DEVICE_CLASS(klass);
119  
120      dc->realize = bcm2835_thermal_realize;
121      device_class_set_legacy_reset(dc, bcm2835_thermal_reset);
122      dc->vmsd = &bcm2835_thermal_vmstate;
123  }
124  
125  static const TypeInfo bcm2835_thermal_info = {
126      .name = TYPE_BCM2835_THERMAL,
127      .parent = TYPE_SYS_BUS_DEVICE,
128      .instance_size = sizeof(Bcm2835ThermalState),
129      .class_init = bcm2835_thermal_class_init,
130  };
131  
bcm2835_thermal_register_types(void)132  static void bcm2835_thermal_register_types(void)
133  {
134      type_register_static(&bcm2835_thermal_info);
135  }
136  
137  type_init(bcm2835_thermal_register_types)
138