hw/timer/altera_timer.c

   1 /*
   2  * QEMU model of the Altera timer.
   3  *
   4  * Copyright (c) 2012 Chris Wulff <crwulff@gmail.com>
   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 2.1 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
  18  * <http://www.gnu.org/licenses/lgpl-2.1.html>
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "qemu/module.h"
  23 #include "qapi/error.h"
  24
  25 #include "hw/sysbus.h"
  26 #include "hw/irq.h"
  27 #include "hw/ptimer.h"
  28 #include "hw/qdev-properties.h"
  29
  30 #define R_STATUS      0
  31 #define R_CONTROL     1
  32 #define R_PERIODL     2
  33 #define R_PERIODH     3
  34 #define R_SNAPL       4
  35 #define R_SNAPH       5
  36 #define R_MAX         6
  37
  38 #define STATUS_TO     0x0001
  39 #define STATUS_RUN    0x0002
  40
  41 #define CONTROL_ITO   0x0001
  42 #define CONTROL_CONT  0x0002
  43 #define CONTROL_START 0x0004
  44 #define CONTROL_STOP  0x0008
  45
  46 #define TYPE_ALTERA_TIMER "ALTR.timer"
  47 #define ALTERA_TIMER(obj) \
  48     OBJECT_CHECK(AlteraTimer, (obj), TYPE_ALTERA_TIMER)
  49
  50 typedef struct AlteraTimer {
  51     SysBusDevice  busdev;
  52     MemoryRegion  mmio;
  53     qemu_irq      irq;
  54     uint32_t      freq_hz;
  55     ptimer_state *ptimer;
  56     uint32_t      regs[R_MAX];
  57 } AlteraTimer;
  58
  59 static int timer_irq_state(AlteraTimer *t)
  60 {
  61     bool irq = (t->regs[R_STATUS] & STATUS_TO) &&
  62                (t->regs[R_CONTROL] & CONTROL_ITO);
  63     return irq;
  64 }
  65
  66 static uint64_t timer_read(void *opaque, hwaddr addr,
  67                            unsigned int size)
  68 {
  69     AlteraTimer *t = opaque;
  70     uint64_t r = 0;
  71
  72     addr >>= 2;
  73
  74     switch (addr) {
  75     case R_CONTROL:
  76         r = t->regs[R_CONTROL] & (CONTROL_ITO | CONTROL_CONT);
  77         break;
  78
  79     default:
  80         if (addr < ARRAY_SIZE(t->regs)) {
  81             r = t->regs[addr];
  82         }
  83         break;
  84     }
  85
  86     return r;
  87 }
  88
  89 static void timer_write(void *opaque, hwaddr addr,
  90                         uint64_t value, unsigned int size)
  91 {
  92     AlteraTimer *t = opaque;
  93     uint64_t tvalue;
  94     uint32_t count = 0;
  95     int irqState = timer_irq_state(t);
  96
  97     addr >>= 2;
  98
  99     switch (addr) {
 100     case R_STATUS:
 101         /* The timeout bit is cleared by writing the status register. */
 102         t->regs[R_STATUS] &= ~STATUS_TO;
 103         break;
 104
 105     case R_CONTROL:
 106         ptimer_transaction_begin(t->ptimer);
 107         t->regs[R_CONTROL] = value & (CONTROL_ITO | CONTROL_CONT);
 108         if ((value & CONTROL_START) &&
 109             !(t->regs[R_STATUS] & STATUS_RUN)) {
 110             ptimer_run(t->ptimer, 1);
 111             t->regs[R_STATUS] |= STATUS_RUN;
 112         }
 113         if ((value & CONTROL_STOP) && (t->regs[R_STATUS] & STATUS_RUN)) {
 114             ptimer_stop(t->ptimer);
 115             t->regs[R_STATUS] &= ~STATUS_RUN;
 116         }
 117         ptimer_transaction_commit(t->ptimer);
 118         break;
 119
 120     case R_PERIODL:
 121     case R_PERIODH:
 122         ptimer_transaction_begin(t->ptimer);
 123         t->regs[addr] = value & 0xFFFF;
 124         if (t->regs[R_STATUS] & STATUS_RUN) {
 125             ptimer_stop(t->ptimer);
 126             t->regs[R_STATUS] &= ~STATUS_RUN;
 127         }
 128         tvalue = (t->regs[R_PERIODH] << 16) | t->regs[R_PERIODL];
 129         ptimer_set_limit(t->ptimer, tvalue + 1, 1);
 130         ptimer_transaction_commit(t->ptimer);
 131         break;
 132
 133     case R_SNAPL:
 134     case R_SNAPH:
 135         count = ptimer_get_count(t->ptimer);
 136         t->regs[R_SNAPL] = count & 0xFFFF;
 137         t->regs[R_SNAPH] = count >> 16;
 138         break;
 139
 140     default:
 141         break;
 142     }
 143
 144     if (irqState != timer_irq_state(t)) {
 145         qemu_set_irq(t->irq, timer_irq_state(t));
 146     }
 147 }
 148
 149 static const MemoryRegionOps timer_ops = {
 150     .read = timer_read,
 151     .write = timer_write,
 152     .endianness = DEVICE_NATIVE_ENDIAN,
 153     .valid = {
 154         .min_access_size = 1,
 155         .max_access_size = 4
 156     }
 157 };
 158
 159 static void timer_hit(void *opaque)
 160 {
 161     AlteraTimer *t = opaque;
 162     const uint64_t tvalue = (t->regs[R_PERIODH] << 16) | t->regs[R_PERIODL];
 163
 164     t->regs[R_STATUS] |= STATUS_TO;
 165
 166     ptimer_set_limit(t->ptimer, tvalue + 1, 1);
 167
 168     if (!(t->regs[R_CONTROL] & CONTROL_CONT)) {
 169         t->regs[R_STATUS] &= ~STATUS_RUN;
 170         ptimer_set_count(t->ptimer, tvalue);
 171     } else {
 172         ptimer_run(t->ptimer, 1);
 173     }
 174
 175     qemu_set_irq(t->irq, timer_irq_state(t));
 176 }
 177
 178 static void altera_timer_realize(DeviceState *dev, Error **errp)
 179 {
 180     AlteraTimer *t = ALTERA_TIMER(dev);
 181     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
 182
 183     if (t->freq_hz == 0) {
 184         error_setg(errp, "\"clock-frequency\" property must be provided.");
 185         return;
 186     }
 187
 188     t->ptimer = ptimer_init(timer_hit, t, PTIMER_POLICY_DEFAULT);
 189     ptimer_transaction_begin(t->ptimer);
 190     ptimer_set_freq(t->ptimer, t->freq_hz);
 191     ptimer_transaction_commit(t->ptimer);
 192
 193     memory_region_init_io(&t->mmio, OBJECT(t), &timer_ops, t,
 194                           TYPE_ALTERA_TIMER, R_MAX * sizeof(uint32_t));
 195     sysbus_init_mmio(sbd, &t->mmio);
 196 }
 197
 198 static void altera_timer_init(Object *obj)
 199 {
 200     AlteraTimer *t = ALTERA_TIMER(obj);
 201     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
 202
 203     sysbus_init_irq(sbd, &t->irq);
 204 }
 205
 206 static void altera_timer_reset(DeviceState *dev)
 207 {
 208     AlteraTimer *t = ALTERA_TIMER(dev);
 209
 210     ptimer_transaction_begin(t->ptimer);
 211     ptimer_stop(t->ptimer);
 212     ptimer_set_limit(t->ptimer, 0xffffffff, 1);
 213     ptimer_transaction_commit(t->ptimer);
 214     memset(t->regs, 0, sizeof(t->regs));
 215 }
 216
 217 static Property altera_timer_properties[] = {
 218     DEFINE_PROP_UINT32("clock-frequency", AlteraTimer, freq_hz, 0),
 219     DEFINE_PROP_END_OF_LIST(),
 220 };
 221
 222 static void altera_timer_class_init(ObjectClass *klass, void *data)
 223 {
 224     DeviceClass *dc = DEVICE_CLASS(klass);
 225
 226     dc->realize = altera_timer_realize;
 227     device_class_set_props(dc, altera_timer_properties);
 228     dc->reset = altera_timer_reset;
 229 }
 230
 231 static const TypeInfo altera_timer_info = {
 232     .name          = TYPE_ALTERA_TIMER,
 233     .parent        = TYPE_SYS_BUS_DEVICE,
 234     .instance_size = sizeof(AlteraTimer),
 235     .instance_init = altera_timer_init,
 236     .class_init    = altera_timer_class_init,
 237 };
 238
 239 static void altera_timer_register(void)
 240 {
 241     type_register_static(&altera_timer_info);
 242 }
 243
 244 type_init(altera_timer_register)