hw/rtc/m41t80.c

   1 /*
   2  * M41T80 serial rtc emulation
   3  *
   4  * Copyright (c) 2018 BALATON Zoltan
   5  *
   6  * This work is licensed under the GNU GPL license version 2 or later.
   7  *
   8  */
   9
  10 #include "qemu/osdep.h"
  11 #include "qemu/log.h"
  12 #include "qemu/module.h"
  13 #include "qemu/timer.h"
  14 #include "qemu/bcd.h"
  15 #include "hw/i2c/i2c.h"
  16 #include "qom/object.h"
  17 #include "sysemu/rtc.h"
  18
  19 #define TYPE_M41T80 "m41t80"
  20 OBJECT_DECLARE_SIMPLE_TYPE(M41t80State, M41T80)
  21
  22 struct M41t80State {
  23     I2CSlave parent_obj;
  24     int8_t addr;
  25 };
  26
  27 static void m41t80_realize(DeviceState *dev, Error **errp)
  28 {
  29     M41t80State *s = M41T80(dev);
  30
  31     s->addr = -1;
  32 }
  33
  34 static int m41t80_send(I2CSlave *i2c, uint8_t data)
  35 {
  36     M41t80State *s = M41T80(i2c);
  37
  38     if (s->addr < 0) {
  39         s->addr = data;
  40     } else {
  41         s->addr++;
  42     }
  43     return 0;
  44 }
  45
  46 static uint8_t m41t80_recv(I2CSlave *i2c)
  47 {
  48     M41t80State *s = M41T80(i2c);
  49     struct tm now;
  50     int64_t rt;
  51
  52     if (s->addr < 0) {
  53         s->addr = 0;
  54     }
  55     if (s->addr >= 1 && s->addr <= 7) {
  56         qemu_get_timedate(&now, -1);
  57     }
  58     switch (s->addr++) {
  59     case 0:
  60         rt = g_get_real_time();
  61         return to_bcd((rt % G_USEC_PER_SEC) / 10000);
  62     case 1:
  63         return to_bcd(now.tm_sec);
  64     case 2:
  65         return to_bcd(now.tm_min);
  66     case 3:
  67         return to_bcd(now.tm_hour);
  68     case 4:
  69         return to_bcd(now.tm_wday);
  70     case 5:
  71         return to_bcd(now.tm_mday);
  72     case 6:
  73         return to_bcd(now.tm_mon + 1);
  74     case 7:
  75         return to_bcd(now.tm_year % 100);
  76     case 8 ... 19:
  77         qemu_log_mask(LOG_UNIMP, "%s: unimplemented register: %d\n",
  78                       __func__, s->addr - 1);
  79         return 0;
  80     default:
  81         qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid register: %d\n",
  82                       __func__, s->addr - 1);
  83         return 0;
  84     }
  85 }
  86
  87 static int m41t80_event(I2CSlave *i2c, enum i2c_event event)
  88 {
  89     M41t80State *s = M41T80(i2c);
  90
  91     if (event == I2C_START_SEND) {
  92         s->addr = -1;
  93     }
  94     return 0;
  95 }
  96
  97 static void m41t80_class_init(ObjectClass *klass, void *data)
  98 {
  99     DeviceClass *dc = DEVICE_CLASS(klass);
 100     I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
 101
 102     dc->realize = m41t80_realize;
 103     sc->send = m41t80_send;
 104     sc->recv = m41t80_recv;
 105     sc->event = m41t80_event;
 106 }
 107
 108 static const TypeInfo m41t80_info = {
 109     .name          = TYPE_M41T80,
 110     .parent        = TYPE_I2C_SLAVE,
 111     .instance_size = sizeof(M41t80State),
 112     .class_init    = m41t80_class_init,
 113 };
 114
 115 static void m41t80_register_types(void)
 116 {
 117     type_register_static(&m41t80_info);
 118 }
 119
 120 type_init(m41t80_register_types)