@samitouri / QOSamiQemu
Code Commits Issues Pulls Sessions CI/CD
master
master
c 178 lines 5.21 KB
Raw
1 /*
2 * BCM2835 SYS timer emulation
3 *
4 * Copyright (C) 2019 Philippe Mathieu-Daudé
5 *
6 * SPDX-License-Identifier: GPL-2.0-or-later
7 *
8 * Datasheet: BCM2835 ARM Peripherals (C6357-M-1398)
9 * https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf
10 *
11 * Only the free running 64-bit counter is implemented.
12 * The 4 COMPARE registers and the interruption are not implemented.
13 */
14
15 #include "qemu/osdep.h"
16 #include "qemu/log.h"
17 #include "qemu/timer.h"
18 #include "hw/timer/bcm2835_systmr.h"
19 #include "hw/core/registerfields.h"
20 #include "migration/vmstate.h"
21 #include "trace.h"
22
23 REG32(CTRL_STATUS, 0x00)
24 REG32(COUNTER_LOW, 0x04)
25 REG32(COUNTER_HIGH, 0x08)
26 REG32(COMPARE0, 0x0c)
27 REG32(COMPARE1, 0x10)
28 REG32(COMPARE2, 0x14)
29 REG32(COMPARE3, 0x18)
30
31 static void bcm2835_systmr_timer_expire(void *opaque)
32 {
33 BCM2835SystemTimerCompare *tmr = opaque;
34
35 trace_bcm2835_systmr_timer_expired(tmr->id);
36 tmr->state->reg.ctrl_status |= 1 << tmr->id;
37 qemu_set_irq(tmr->irq, 1);
38 }
39
40 static uint64_t bcm2835_systmr_read(void *opaque, hwaddr offset,
41 unsigned size)
42 {
43 BCM2835SystemTimerState *s = BCM2835_SYSTIMER(opaque);
44 uint64_t r = 0;
45
46 switch (offset) {
47 case A_CTRL_STATUS:
48 r = s->reg.ctrl_status;
49 break;
50 case A_COMPARE0 ... A_COMPARE3:
51 r = s->reg.compare[(offset - A_COMPARE0) >> 2];
52 break;
53 case A_COUNTER_LOW:
54 case A_COUNTER_HIGH:
55 /* Free running counter at 1MHz */
56 r = qemu_clock_get_us(QEMU_CLOCK_VIRTUAL);
57 r >>= 8 * (offset - A_COUNTER_LOW);
58 r &= UINT32_MAX;
59 break;
60 default:
61 qemu_log_mask(LOG_GUEST_ERROR, "%s: bad offset 0x%" HWADDR_PRIx "\n",
62 __func__, offset);
63 break;
64 }
65 trace_bcm2835_systmr_read(offset, r);
66
67 return r;
68 }
69
70 static void bcm2835_systmr_write(void *opaque, hwaddr offset,
71 uint64_t value64, unsigned size)
72 {
73 BCM2835SystemTimerState *s = BCM2835_SYSTIMER(opaque);
74 int index;
75 uint32_t value = value64;
76 uint32_t triggers_delay_us;
77 uint64_t now;
78
79 trace_bcm2835_systmr_write(offset, value);
80 switch (offset) {
81 case A_CTRL_STATUS:
82 s->reg.ctrl_status &= ~value; /* Ack */
83 for (index = 0; index < ARRAY_SIZE(s->tmr); index++) {
84 if (extract32(value, index, 1)) {
85 trace_bcm2835_systmr_irq_ack(index);
86 qemu_set_irq(s->tmr[index].irq, 0);
87 }
88 }
89 break;
90 case A_COMPARE0 ... A_COMPARE3:
91 index = (offset - A_COMPARE0) >> 2;
92 s->reg.compare[index] = value;
93 now = qemu_clock_get_us(QEMU_CLOCK_VIRTUAL);
94 /* Compare lower 32-bits of the free-running counter. */
95 triggers_delay_us = value - now;
96 trace_bcm2835_systmr_run(index, triggers_delay_us);
97 timer_mod(&s->tmr[index].timer, now + triggers_delay_us);
98 break;
99 case A_COUNTER_LOW:
100 case A_COUNTER_HIGH:
101 qemu_log_mask(LOG_GUEST_ERROR, "%s: read-only ofs 0x%" HWADDR_PRIx "\n",
102 __func__, offset);
103 break;
104 default:
105 qemu_log_mask(LOG_GUEST_ERROR, "%s: bad offset 0x%" HWADDR_PRIx "\n",
106 __func__, offset);
107 break;
108 }
109 }
110
111 static const MemoryRegionOps bcm2835_systmr_ops = {
112 .read = bcm2835_systmr_read,
113 .write = bcm2835_systmr_write,
114 .endianness = DEVICE_LITTLE_ENDIAN,
115 .impl = {
116 .min_access_size = 4,
117 .max_access_size = 4,
118 },
119 };
120
121 static void bcm2835_systmr_reset(DeviceState *dev)
122 {
123 BCM2835SystemTimerState *s = BCM2835_SYSTIMER(dev);
124
125 memset(&s->reg, 0, sizeof(s->reg));
126 }
127
128 static void bcm2835_systmr_realize(DeviceState *dev, Error **errp)
129 {
130 BCM2835SystemTimerState *s = BCM2835_SYSTIMER(dev);
131
132 memory_region_init_io(&s->iomem, OBJECT(dev), &bcm2835_systmr_ops,
133 s, "bcm2835-sys-timer", 0x20);
134 sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
135
136 for (size_t i = 0; i < ARRAY_SIZE(s->tmr); i++) {
137 s->tmr[i].id = i;
138 s->tmr[i].state = s;
139 sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->tmr[i].irq);
140 timer_init_us(&s->tmr[i].timer, QEMU_CLOCK_VIRTUAL,
141 bcm2835_systmr_timer_expire, &s->tmr[i]);
142 }
143 }
144
145 static const VMStateDescription bcm2835_systmr_vmstate = {
146 .name = "bcm2835_sys_timer",
147 .version_id = 1,
148 .minimum_version_id = 1,
149 .fields = (const VMStateField[]) {
150 VMSTATE_UINT32(reg.ctrl_status, BCM2835SystemTimerState),
151 VMSTATE_UINT32_ARRAY(reg.compare, BCM2835SystemTimerState,
152 BCM2835_SYSTIMER_COUNT),
153 VMSTATE_END_OF_LIST()
154 }
155 };
156
157 static void bcm2835_systmr_class_init(ObjectClass *klass, const void *data)
158 {
159 DeviceClass *dc = DEVICE_CLASS(klass);
160
161 dc->realize = bcm2835_systmr_realize;
162 device_class_set_legacy_reset(dc, bcm2835_systmr_reset);
163 dc->vmsd = &bcm2835_systmr_vmstate;
164 }
165
166 static const TypeInfo bcm2835_systmr_info = {
167 .name = TYPE_BCM2835_SYSTIMER,
168 .parent = TYPE_SYS_BUS_DEVICE,
169 .instance_size = sizeof(BCM2835SystemTimerState),
170 .class_init = bcm2835_systmr_class_init,
171 };
172
173 static void bcm2835_systmr_register_types(void)
174 {
175 type_register_static(&bcm2835_systmr_info);
176 }
177
178 type_init(bcm2835_systmr_register_types);