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