hw/timer/lm32_timer.c

   1 /*
   2  *  QEMU model of the LatticeMico32 timer block.
   3  *
   4  *  Copyright (c) 2010 Michael Walle <michael@walle.cc>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  *
  20  * Specification available at:
  21  *   http://www.latticesemi.com/documents/mico32timer.pdf
  22  */
  23
  24 #include "qemu/osdep.h"
  25 #include "hw/irq.h"
  26 #include "hw/sysbus.h"
  27 #include "migration/vmstate.h"
  28 #include "trace.h"
  29 #include "qemu/timer.h"
  30 #include "hw/ptimer.h"
  31 #include "hw/qdev-properties.h"
  32 #include "qemu/error-report.h"
  33 #include "qemu/module.h"
  34
  35 #define DEFAULT_FREQUENCY (50*1000000)
  36
  37 enum {
  38     R_SR = 0,
  39     R_CR,
  40     R_PERIOD,
  41     R_SNAPSHOT,
  42     R_MAX
  43 };
  44
  45 enum {
  46     SR_TO    = (1 << 0),
  47     SR_RUN   = (1 << 1),
  48 };
  49
  50 enum {
  51     CR_ITO   = (1 << 0),
  52     CR_CONT  = (1 << 1),
  53     CR_START = (1 << 2),
  54     CR_STOP  = (1 << 3),
  55 };
  56
  57 #define TYPE_LM32_TIMER "lm32-timer"
  58 #define LM32_TIMER(obj) OBJECT_CHECK(LM32TimerState, (obj), TYPE_LM32_TIMER)
  59
  60 struct LM32TimerState {
  61     SysBusDevice parent_obj;
  62
  63     MemoryRegion iomem;
  64
  65     ptimer_state *ptimer;
  66
  67     qemu_irq irq;
  68     uint32_t freq_hz;
  69
  70     uint32_t regs[R_MAX];
  71 };
  72 typedef struct LM32TimerState LM32TimerState;
  73
  74 static void timer_update_irq(LM32TimerState *s)
  75 {
  76     int state = (s->regs[R_SR] & SR_TO) && (s->regs[R_CR] & CR_ITO);
  77
  78     trace_lm32_timer_irq_state(state);
  79     qemu_set_irq(s->irq, state);
  80 }
  81
  82 static uint64_t timer_read(void *opaque, hwaddr addr, unsigned size)
  83 {
  84     LM32TimerState *s = opaque;
  85     uint32_t r = 0;
  86
  87     addr >>= 2;
  88     switch (addr) {
  89     case R_SR:
  90     case R_CR:
  91     case R_PERIOD:
  92         r = s->regs[addr];
  93         break;
  94     case R_SNAPSHOT:
  95         r = (uint32_t)ptimer_get_count(s->ptimer);
  96         break;
  97     default:
  98         error_report("lm32_timer: read access to unknown register 0x"
  99                 TARGET_FMT_plx, addr << 2);
 100         break;
 101     }
 102
 103     trace_lm32_timer_memory_read(addr << 2, r);
 104     return r;
 105 }
 106
 107 static void timer_write(void *opaque, hwaddr addr,
 108                         uint64_t value, unsigned size)
 109 {
 110     LM32TimerState *s = opaque;
 111
 112     trace_lm32_timer_memory_write(addr, value);
 113
 114     addr >>= 2;
 115     switch (addr) {
 116     case R_SR:
 117         s->regs[R_SR] &= ~SR_TO;
 118         break;
 119     case R_CR:
 120         ptimer_transaction_begin(s->ptimer);
 121         s->regs[R_CR] = value;
 122         if (s->regs[R_CR] & CR_START) {
 123             ptimer_run(s->ptimer, 1);
 124         }
 125         if (s->regs[R_CR] & CR_STOP) {
 126             ptimer_stop(s->ptimer);
 127         }
 128         ptimer_transaction_commit(s->ptimer);
 129         break;
 130     case R_PERIOD:
 131         s->regs[R_PERIOD] = value;
 132         ptimer_transaction_begin(s->ptimer);
 133         ptimer_set_count(s->ptimer, value);
 134         ptimer_transaction_commit(s->ptimer);
 135         break;
 136     case R_SNAPSHOT:
 137         error_report("lm32_timer: write access to read only register 0x"
 138                 TARGET_FMT_plx, addr << 2);
 139         break;
 140     default:
 141         error_report("lm32_timer: write access to unknown register 0x"
 142                 TARGET_FMT_plx, addr << 2);
 143         break;
 144     }
 145     timer_update_irq(s);
 146 }
 147
 148 static const MemoryRegionOps timer_ops = {
 149     .read = timer_read,
 150     .write = timer_write,
 151     .endianness = DEVICE_NATIVE_ENDIAN,
 152     .valid = {
 153         .min_access_size = 4,
 154         .max_access_size = 4,
 155     },
 156 };
 157
 158 static void timer_hit(void *opaque)
 159 {
 160     LM32TimerState *s = opaque;
 161
 162     trace_lm32_timer_hit();
 163
 164     s->regs[R_SR] |= SR_TO;
 165
 166     if (s->regs[R_CR] & CR_CONT) {
 167         ptimer_set_count(s->ptimer, s->regs[R_PERIOD]);
 168         ptimer_run(s->ptimer, 1);
 169     }
 170     timer_update_irq(s);
 171 }
 172
 173 static void timer_reset(DeviceState *d)
 174 {
 175     LM32TimerState *s = LM32_TIMER(d);
 176     int i;
 177
 178     for (i = 0; i < R_MAX; i++) {
 179         s->regs[i] = 0;
 180     }
 181     ptimer_transaction_begin(s->ptimer);
 182     ptimer_stop(s->ptimer);
 183     ptimer_transaction_commit(s->ptimer);
 184 }
 185
 186 static void lm32_timer_init(Object *obj)
 187 {
 188     LM32TimerState *s = LM32_TIMER(obj);
 189     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
 190
 191     sysbus_init_irq(dev, &s->irq);
 192
 193     memory_region_init_io(&s->iomem, obj, &timer_ops, s,
 194                           "timer", R_MAX * 4);
 195     sysbus_init_mmio(dev, &s->iomem);
 196 }
 197
 198 static void lm32_timer_realize(DeviceState *dev, Error **errp)
 199 {
 200     LM32TimerState *s = LM32_TIMER(dev);
 201
 202     s->ptimer = ptimer_init(timer_hit, s, PTIMER_POLICY_DEFAULT);
 203
 204     ptimer_transaction_begin(s->ptimer);
 205     ptimer_set_freq(s->ptimer, s->freq_hz);
 206     ptimer_transaction_commit(s->ptimer);
 207 }
 208
 209 static const VMStateDescription vmstate_lm32_timer = {
 210     .name = "lm32-timer",
 211     .version_id = 1,
 212     .minimum_version_id = 1,
 213     .fields = (VMStateField[]) {
 214         VMSTATE_PTIMER(ptimer, LM32TimerState),
 215         VMSTATE_UINT32(freq_hz, LM32TimerState),
 216         VMSTATE_UINT32_ARRAY(regs, LM32TimerState, R_MAX),
 217         VMSTATE_END_OF_LIST()
 218     }
 219 };
 220
 221 static Property lm32_timer_properties[] = {
 222     DEFINE_PROP_UINT32("frequency", LM32TimerState, freq_hz, DEFAULT_FREQUENCY),
 223     DEFINE_PROP_END_OF_LIST(),
 224 };
 225
 226 static void lm32_timer_class_init(ObjectClass *klass, void *data)
 227 {
 228     DeviceClass *dc = DEVICE_CLASS(klass);
 229
 230     dc->realize = lm32_timer_realize;
 231     dc->reset = timer_reset;
 232     dc->vmsd = &vmstate_lm32_timer;
 233     device_class_set_props(dc, lm32_timer_properties);
 234 }
 235
 236 static const TypeInfo lm32_timer_info = {
 237     .name          = TYPE_LM32_TIMER,
 238     .parent        = TYPE_SYS_BUS_DEVICE,
 239     .instance_size = sizeof(LM32TimerState),
 240     .instance_init = lm32_timer_init,
 241     .class_init    = lm32_timer_class_init,
 242 };
 243
 244 static void lm32_timer_register_types(void)
 245 {
 246     type_register_static(&lm32_timer_info);
 247 }
 248
 249 type_init(lm32_timer_register_types)