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/main-loop.h"
  33 #include "qemu/log.h"
  34
  35 #include "hw/timer/digic-timer.h"
  36
  37 static const VMStateDescription vmstate_digic_timer = {
  38     .name = "digic.timer",
  39     .version_id = 1,
  40     .minimum_version_id = 1,
  41     .fields = (VMStateField[]) {
  42         VMSTATE_PTIMER(ptimer, DigicTimerState),
  43         VMSTATE_UINT32(control, DigicTimerState),
  44         VMSTATE_UINT32(relvalue, DigicTimerState),
  45         VMSTATE_END_OF_LIST()
  46     }
  47 };
  48
  49 static void digic_timer_reset(DeviceState *dev)
  50 {
  51     DigicTimerState *s = DIGIC_TIMER(dev);
  52
  53     ptimer_stop(s->ptimer);
  54     s->control = 0;
  55     s->relvalue = 0;
  56 }
  57
  58 static uint64_t digic_timer_read(void *opaque, hwaddr offset, unsigned size)
  59 {
  60     DigicTimerState *s = opaque;
  61     uint64_t ret = 0;
  62
  63     switch (offset) {
  64     case DIGIC_TIMER_CONTROL:
  65         ret = s->control;
  66         break;
  67     case DIGIC_TIMER_RELVALUE:
  68         ret = s->relvalue;
  69         break;
  70     case DIGIC_TIMER_VALUE:
  71         ret = ptimer_get_count(s->ptimer) & 0xffff;
  72         break;
  73     default:
  74         qemu_log_mask(LOG_UNIMP,
  75                       "digic-timer: read access to unknown register 0x"
  76                       TARGET_FMT_plx "\n", offset);
  77     }
  78
  79     return ret;
  80 }
  81
  82 static void digic_timer_write(void *opaque, hwaddr offset,
  83                               uint64_t value, unsigned size)
  84 {
  85     DigicTimerState *s = opaque;
  86
  87     switch (offset) {
  88     case DIGIC_TIMER_CONTROL:
  89         if (value & DIGIC_TIMER_CONTROL_RST) {
  90             digic_timer_reset((DeviceState *)s);
  91             break;
  92         }
  93
  94         if (value & DIGIC_TIMER_CONTROL_EN) {
  95             ptimer_run(s->ptimer, 0);
  96         }
  97
  98         s->control = (uint32_t)value;
  99         break;
 100
 101     case DIGIC_TIMER_RELVALUE:
 102         s->relvalue = extract32(value, 0, 16);
 103         ptimer_set_limit(s->ptimer, s->relvalue, 1);
 104         break;
 105
 106     case DIGIC_TIMER_VALUE:
 107         break;
 108
 109     default:
 110         qemu_log_mask(LOG_UNIMP,
 111                       "digic-timer: read access to unknown register 0x"
 112                       TARGET_FMT_plx "\n", offset);
 113     }
 114 }
 115
 116 static const MemoryRegionOps digic_timer_ops = {
 117     .read = digic_timer_read,
 118     .write = digic_timer_write,
 119     .impl = {
 120         .min_access_size = 4,
 121         .max_access_size = 4,
 122     },
 123     .endianness = DEVICE_NATIVE_ENDIAN,
 124 };
 125
 126 static void digic_timer_init(Object *obj)
 127 {
 128     DigicTimerState *s = DIGIC_TIMER(obj);
 129
 130     s->ptimer = ptimer_init(NULL, PTIMER_POLICY_DEFAULT);
 131
 132     /*
 133      * FIXME: there is no documentation on Digic timer
 134      * frequency setup so let it always run at 1 MHz
 135      */
 136     ptimer_set_freq(s->ptimer, 1 * 1000 * 1000);
 137
 138     memory_region_init_io(&s->iomem, OBJECT(s), &digic_timer_ops, s,
 139                           TYPE_DIGIC_TIMER, 0x100);
 140     sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->iomem);
 141 }
 142
 143 static void digic_timer_class_init(ObjectClass *klass, void *class_data)
 144 {
 145     DeviceClass *dc = DEVICE_CLASS(klass);
 146
 147     dc->reset = digic_timer_reset;
 148     dc->vmsd = &vmstate_digic_timer;
 149 }
 150
 151 static const TypeInfo digic_timer_info = {
 152     .name = TYPE_DIGIC_TIMER,
 153     .parent = TYPE_SYS_BUS_DEVICE,
 154     .instance_size = sizeof(DigicTimerState),
 155     .instance_init = digic_timer_init,
 156     .class_init = digic_timer_class_init,
 157 };
 158
 159 static void digic_timer_register_type(void)
 160 {
 161     type_register_static(&digic_timer_info);
 162 }
 163
 164 type_init(digic_timer_register_type)