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