hw/timer/digic-timer.c

   1 /*
   2  * QEMU model of the Canon DIGIC timer block.
   3  *
   4  * Copyright (C) 2013 Antony Pavlov <antonynpavlov@gmail.com>
   5  *
   6  * This model is based on reverse engineering efforts
   7  * made by CHDK (http://chdk.wikia.com) and
   8  * Magic Lantern (http://www.magiclantern.fm) projects
   9  * contributors.
  10  *
  11  * See "Timer/Clock Module" docs here:
  12  *   http://magiclantern.wikia.com/wiki/Register_Map
  13  *
  14  * The QEMU model of the OSTimer in PKUnity SoC by Guan Xuetao
  15  * is used as a template.
  16  *
  17  * This program is free software; you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License as published by
  19  * the Free Software Foundation; either version 2 of the License, or
  20  * (at your option) any later version.
  21  *
  22  * This program is distributed in the hope that it will be useful,
  23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  25  * GNU General Public License for more details.
  26  *
  27  */
  28
  29 #include "qemu/osdep.h"
  30 #include "hw/sysbus.h"
  31 #include "hw/ptimer.h"
  32 #include "qemu/module.h"
  33 #include "qemu/log.h"
  34
  35 #include "hw/timer/digic-timer.h"
  36 #include "migration/vmstate.h"
  37
  38 static const VMStateDescription vmstate_digic_timer = {
  39     .name = "digic.timer",
  40     .version_id = 1,
  41     .minimum_version_id = 1,
  42     .fields = (VMStateField[]) {
  43         VMSTATE_PTIMER(ptimer, DigicTimerState),
  44         VMSTATE_UINT32(control, DigicTimerState),
  45         VMSTATE_UINT32(relvalue, DigicTimerState),
  46         VMSTATE_END_OF_LIST()
  47     }
  48 };
  49
  50 static void digic_timer_reset(DeviceState *dev)
  51 {
  52     DigicTimerState *s = DIGIC_TIMER(dev);
  53
  54     ptimer_transaction_begin(s->ptimer);
  55     ptimer_stop(s->ptimer);
  56     ptimer_transaction_commit(s->ptimer);
  57     s->control = 0;
  58     s->relvalue = 0;
  59 }
  60
  61 static uint64_t digic_timer_read(void *opaque, hwaddr offset, unsigned size)
  62 {
  63     DigicTimerState *s = opaque;
  64     uint64_t ret = 0;
  65
  66     switch (offset) {
  67     case DIGIC_TIMER_CONTROL:
  68         ret = s->control;
  69         break;
  70     case DIGIC_TIMER_RELVALUE:
  71         ret = s->relvalue;
  72         break;
  73     case DIGIC_TIMER_VALUE:
  74         ret = ptimer_get_count(s->ptimer) & 0xffff;
  75         break;
  76     default:
  77         qemu_log_mask(LOG_UNIMP,
  78                       "digic-timer: read access to unknown register 0x"
  79                       TARGET_FMT_plx "\n", offset);
  80     }
  81
  82     return ret;
  83 }
  84
  85 static void digic_timer_write(void *opaque, hwaddr offset,
  86                               uint64_t value, unsigned size)
  87 {
  88     DigicTimerState *s = opaque;
  89
  90     switch (offset) {
  91     case DIGIC_TIMER_CONTROL:
  92         if (value & DIGIC_TIMER_CONTROL_RST) {
  93             digic_timer_reset((DeviceState *)s);
  94             break;
  95         }
  96
  97         ptimer_transaction_begin(s->ptimer);
  98         if (value & DIGIC_TIMER_CONTROL_EN) {
  99             ptimer_run(s->ptimer, 0);
 100         }
 101
 102         s->control = (uint32_t)value;
 103         ptimer_transaction_commit(s->ptimer);
 104         break;
 105
 106     case DIGIC_TIMER_RELVALUE:
 107         s->relvalue = extract32(value, 0, 16);
 108         ptimer_transaction_begin(s->ptimer);
 109         ptimer_set_limit(s->ptimer, s->relvalue, 1);
 110         ptimer_transaction_commit(s->ptimer);
 111         break;
 112
 113     case DIGIC_TIMER_VALUE:
 114         break;
 115
 116     default:
 117         qemu_log_mask(LOG_UNIMP,
 118                       "digic-timer: read access to unknown register 0x"
 119                       TARGET_FMT_plx "\n", offset);
 120     }
 121 }
 122
 123 static const MemoryRegionOps digic_timer_ops = {
 124     .read = digic_timer_read,
 125     .write = digic_timer_write,
 126     .impl = {
 127         .min_access_size = 4,
 128         .max_access_size = 4,
 129     },
 130     .endianness = DEVICE_NATIVE_ENDIAN,
 131 };
 132
 133 static void digic_timer_tick(void *opaque)
 134 {
 135     /* Nothing to do on timer rollover */
 136 }
 137
 138 static void digic_timer_init(Object *obj)
 139 {
 140     DigicTimerState *s = DIGIC_TIMER(obj);
 141
 142     s->ptimer = ptimer_init(digic_timer_tick, NULL, PTIMER_POLICY_DEFAULT);
 143
 144     /*
 145      * FIXME: there is no documentation on Digic timer
 146      * frequency setup so let it always run at 1 MHz
 147      */
 148     ptimer_transaction_begin(s->ptimer);
 149     ptimer_set_freq(s->ptimer, 1 * 1000 * 1000);
 150     ptimer_transaction_commit(s->ptimer);
 151
 152     memory_region_init_io(&s->iomem, OBJECT(s), &digic_timer_ops, s,
 153                           TYPE_DIGIC_TIMER, 0x100);
 154     sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->iomem);
 155 }
 156
 157 static void digic_timer_class_init(ObjectClass *klass, void *class_data)
 158 {
 159     DeviceClass *dc = DEVICE_CLASS(klass);
 160
 161     dc->reset = digic_timer_reset;
 162     dc->vmsd = &vmstate_digic_timer;
 163 }
 164
 165 static const TypeInfo digic_timer_info = {
 166     .name = TYPE_DIGIC_TIMER,
 167     .parent = TYPE_SYS_BUS_DEVICE,
 168     .instance_size = sizeof(DigicTimerState),
 169     .instance_init = digic_timer_init,
 170     .class_init = digic_timer_class_init,
 171 };
 172
 173 static void digic_timer_register_type(void)
 174 {
 175     type_register_static(&digic_timer_info);
 176 }
 177
 178 type_init(digic_timer_register_type)