hw/syborg_rtc.c

   1 /*
   2  * Syborg RTC
   3  *
   4  * Copyright (c) 2008 CodeSourcery
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "sysbus.h"
  26 #include "qemu-timer.h"
  27 #include "syborg.h"
  28
  29 enum {
  30     RTC_ID        = 0,
  31     RTC_LATCH     = 1,
  32     RTC_DATA_LOW  = 2,
  33     RTC_DATA_HIGH = 3
  34 };
  35
  36 typedef struct {
  37     SysBusDevice busdev;
  38     int64_t offset;
  39     int64_t data;
  40     qemu_irq irq;
  41 } SyborgRTCState;
  42
  43 static uint32_t syborg_rtc_read(void *opaque, target_phys_addr_t offset)
  44 {
  45     SyborgRTCState *s = (SyborgRTCState *)opaque;
  46     offset &= 0xfff;
  47     switch (offset >> 2) {
  48     case RTC_ID:
  49         return SYBORG_ID_RTC;
  50     case RTC_DATA_LOW:
  51         return (uint32_t)s->data;
  52     case RTC_DATA_HIGH:
  53         return (uint32_t)(s->data >> 32);
  54     default:
  55         cpu_abort(cpu_single_env, "syborg_rtc_read: Bad offset %x\n",
  56                   (int)offset);
  57         return 0;
  58     }
  59 }
  60
  61 static void syborg_rtc_write(void *opaque, target_phys_addr_t offset, uint32_t value)
  62 {
  63     SyborgRTCState *s = (SyborgRTCState *)opaque;
  64     uint64_t now;
  65
  66     offset &= 0xfff;
  67     switch (offset >> 2) {
  68     case RTC_LATCH:
  69         now = qemu_get_clock(vm_clock);
  70         if (value >= 4) {
  71             s->offset = s->data - now;
  72         } else {
  73             s->data = now + s->offset;
  74             while (value) {
  75                 s->data /= 1000;
  76                 value--;
  77             }
  78         }
  79         break;
  80     case RTC_DATA_LOW:
  81         s->data = (s->data & ~(uint64_t)0xffffffffu) | value;
  82         break;
  83     case RTC_DATA_HIGH:
  84         s->data = (s->data & 0xffffffffu) | ((uint64_t)value << 32);
  85         break;
  86     default:
  87         cpu_abort(cpu_single_env, "syborg_rtc_write: Bad offset %x\n",
  88                   (int)offset);
  89         break;
  90     }
  91 }
  92
  93 static CPUReadMemoryFunc *syborg_rtc_readfn[] = {
  94     syborg_rtc_read,
  95     syborg_rtc_read,
  96     syborg_rtc_read
  97 };
  98
  99 static CPUWriteMemoryFunc *syborg_rtc_writefn[] = {
 100     syborg_rtc_write,
 101     syborg_rtc_write,
 102     syborg_rtc_write
 103 };
 104
 105 static void syborg_rtc_save(QEMUFile *f, void *opaque)
 106 {
 107     SyborgRTCState *s = opaque;
 108
 109     qemu_put_be64(f, s->offset);
 110     qemu_put_be64(f, s->data);
 111 }
 112
 113 static int syborg_rtc_load(QEMUFile *f, void *opaque, int version_id)
 114 {
 115     SyborgRTCState *s = opaque;
 116
 117     if (version_id != 1)
 118         return -EINVAL;
 119
 120     s->offset = qemu_get_be64(f);
 121     s->data = qemu_get_be64(f);
 122
 123     return 0;
 124 }
 125
 126 static void syborg_rtc_init(SysBusDevice *dev)
 127 {
 128     SyborgRTCState *s = FROM_SYSBUS(SyborgRTCState, dev);
 129     struct tm tm;
 130     int iomemtype;
 131
 132     iomemtype = cpu_register_io_memory(0, syborg_rtc_readfn,
 133                                        syborg_rtc_writefn, s);
 134     sysbus_init_mmio(dev, 0x1000, iomemtype);
 135
 136     qemu_get_timedate(&tm, 0);
 137     s->offset = (uint64_t)mktime(&tm) * 1000000000;
 138
 139     register_savevm("syborg_rtc", -1, 1, syborg_rtc_save, syborg_rtc_load, s);
 140 }
 141
 142 static void syborg_rtc_register_devices(void)
 143 {
 144     sysbus_register_dev("syborg,rtc", sizeof(SyborgRTCState), syborg_rtc_init);
 145 }
 146
 147 device_init(syborg_rtc_register_devices)