qemu/hw/timer/altera_timer.c
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   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#include "qom/object.h"
  30
  31#define R_STATUS      0
  32#define R_CONTROL     1
  33#define R_PERIODL     2
  34#define R_PERIODH     3
  35#define R_SNAPL       4
  36#define R_SNAPH       5
  37#define R_MAX         6
  38
  39#define STATUS_TO     0x0001
  40#define STATUS_RUN    0x0002
  41
  42#define CONTROL_ITO   0x0001
  43#define CONTROL_CONT  0x0002
  44#define CONTROL_START 0x0004
  45#define CONTROL_STOP  0x0008
  46
  47#define TYPE_ALTERA_TIMER "ALTR.timer"
  48OBJECT_DECLARE_SIMPLE_TYPE(AlteraTimer, ALTERA_TIMER)
  49
  50struct 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};
  58
  59static 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
  66static 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
  89static 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
 149static 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
 159static 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
 178static 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
 198static 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
 206static 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
 217static Property altera_timer_properties[] = {
 218    DEFINE_PROP_UINT32("clock-frequency", AlteraTimer, freq_hz, 0),
 219    DEFINE_PROP_END_OF_LIST(),
 220};
 221
 222static 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
 231static 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
 239static void altera_timer_register(void)
 240{
 241    type_register_static(&altera_timer_info);
 242}
 243
 244type_init(altera_timer_register)
 245