aboutsummaryrefslogtreecommitdiff
path: root/hw/timer/lm32_timer.c
blob: 6ce876c6ae8e5eb6bf6c5f84b1fa9be0c9927162 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
/*
 *  QEMU model of the LatticeMico32 timer block.
 *
 *  Copyright (c) 2010 Michael Walle <michael@walle.cc>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 *
 *
 * Specification available at:
 *   http://www.latticesemi.com/documents/mico32timer.pdf
 */

#include "qemu/osdep.h"
#include "hw/hw.h"
#include "hw/sysbus.h"
#include "trace.h"
#include "qemu/timer.h"
#include "hw/ptimer.h"
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
#include "qemu/module.h"

#define DEFAULT_FREQUENCY (50*1000000)

enum {
    R_SR = 0,
    R_CR,
    R_PERIOD,
    R_SNAPSHOT,
    R_MAX
};

enum {
    SR_TO    = (1 << 0),
    SR_RUN   = (1 << 1),
};

enum {
    CR_ITO   = (1 << 0),
    CR_CONT  = (1 << 1),
    CR_START = (1 << 2),
    CR_STOP  = (1 << 3),
};

#define TYPE_LM32_TIMER "lm32-timer"
#define LM32_TIMER(obj) OBJECT_CHECK(LM32TimerState, (obj), TYPE_LM32_TIMER)

struct LM32TimerState {
    SysBusDevice parent_obj;

    MemoryRegion iomem;

    QEMUBH *bh;
    ptimer_state *ptimer;

    qemu_irq irq;
    uint32_t freq_hz;

    uint32_t regs[R_MAX];
};
typedef struct LM32TimerState LM32TimerState;

static void timer_update_irq(LM32TimerState *s)
{
    int state = (s->regs[R_SR] & SR_TO) && (s->regs[R_CR] & CR_ITO);

    trace_lm32_timer_irq_state(state);
    qemu_set_irq(s->irq, state);
}

static uint64_t timer_read(void *opaque, hwaddr addr, unsigned size)
{
    LM32TimerState *s = opaque;
    uint32_t r = 0;

    addr >>= 2;
    switch (addr) {
    case R_SR:
    case R_CR:
    case R_PERIOD:
        r = s->regs[addr];
        break;
    case R_SNAPSHOT:
        r = (uint32_t)ptimer_get_count(s->ptimer);
        break;
    default:
        error_report("lm32_timer: read access to unknown register 0x"
                TARGET_FMT_plx, addr << 2);
        break;
    }

    trace_lm32_timer_memory_read(addr << 2, r);
    return r;
}

static void timer_write(void *opaque, hwaddr addr,
                        uint64_t value, unsigned size)
{
    LM32TimerState *s = opaque;

    trace_lm32_timer_memory_write(addr, value);

    addr >>= 2;
    switch (addr) {
    case R_SR:
        s->regs[R_SR] &= ~SR_TO;
        break;
    case R_CR:
        s->regs[R_CR] = value;
        if (s->regs[R_CR] & CR_START) {
            ptimer_run(s->ptimer, 1);
        }
        if (s->regs[R_CR] & CR_STOP) {
            ptimer_stop(s->ptimer);
        }
        break;
    case R_PERIOD:
        s->regs[R_PERIOD] = value;
        ptimer_set_count(s->ptimer, value);
        break;
    case R_SNAPSHOT:
        error_report("lm32_timer: write access to read only register 0x"
                TARGET_FMT_plx, addr << 2);
        break;
    default:
        error_report("lm32_timer: write access to unknown register 0x"
                TARGET_FMT_plx, addr << 2);
        break;
    }
    timer_update_irq(s);
}

static const MemoryRegionOps timer_ops = {
    .read = timer_read,
    .write = timer_write,
    .endianness = DEVICE_NATIVE_ENDIAN,
    .valid = {
        .min_access_size = 4,
        .max_access_size = 4,
    },
};

static void timer_hit(void *opaque)
{
    LM32TimerState *s = opaque;

    trace_lm32_timer_hit();

    s->regs[R_SR] |= SR_TO;

    if (s->regs[R_CR] & CR_CONT) {
        ptimer_set_count(s->ptimer, s->regs[R_PERIOD]);
        ptimer_run(s->ptimer, 1);
    }
    timer_update_irq(s);
}

static void timer_reset(DeviceState *d)
{
    LM32TimerState *s = LM32_TIMER(d);
    int i;

    for (i = 0; i < R_MAX; i++) {
        s->regs[i] = 0;
    }
    ptimer_stop(s->ptimer);
}

static void lm32_timer_init(Object *obj)
{
    LM32TimerState *s = LM32_TIMER(obj);
    SysBusDevice *dev = SYS_BUS_DEVICE(obj);

    sysbus_init_irq(dev, &s->irq);

    s->bh = qemu_bh_new(timer_hit, s);
    s->ptimer = ptimer_init(s->bh, PTIMER_POLICY_DEFAULT);

    memory_region_init_io(&s->iomem, obj, &timer_ops, s,
                          "timer", R_MAX * 4);
    sysbus_init_mmio(dev, &s->iomem);
}

static void lm32_timer_realize(DeviceState *dev, Error **errp)
{
    LM32TimerState *s = LM32_TIMER(dev);

    ptimer_set_freq(s->ptimer, s->freq_hz);
}

static const VMStateDescription vmstate_lm32_timer = {
    .name = "lm32-timer",
    .version_id = 1,
    .minimum_version_id = 1,
    .fields = (VMStateField[]) {
        VMSTATE_PTIMER(ptimer, LM32TimerState),
        VMSTATE_UINT32(freq_hz, LM32TimerState),
        VMSTATE_UINT32_ARRAY(regs, LM32TimerState, R_MAX),
        VMSTATE_END_OF_LIST()
    }
};

static Property lm32_timer_properties[] = {
    DEFINE_PROP_UINT32("frequency", LM32TimerState, freq_hz, DEFAULT_FREQUENCY),
    DEFINE_PROP_END_OF_LIST(),
};

static void lm32_timer_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);

    dc->realize = lm32_timer_realize;
    dc->reset = timer_reset;
    dc->vmsd = &vmstate_lm32_timer;
    dc->props = lm32_timer_properties;
}

static const TypeInfo lm32_timer_info = {
    .name          = TYPE_LM32_TIMER,
    .parent        = TYPE_SYS_BUS_DEVICE,
    .instance_size = sizeof(LM32TimerState),
    .instance_init = lm32_timer_init,
    .class_init    = lm32_timer_class_init,
};

static void lm32_timer_register_types(void)
{
    type_register_static(&lm32_timer_info);
}

type_init(lm32_timer_register_types)