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 #include "qom/object.h"
  18
  19 #define TYPE_M41T80 "m41t80"
  20 typedef struct M41t80State M41t80State;
  21 DECLARE_INSTANCE_CHECKER(M41t80State, M41T80,
  22                          TYPE_M41T80)
  23
  24 struct M41t80State {
  25     I2CSlave parent_obj;
  26     int8_t addr;
  27 };
  28
  29 static void m41t80_realize(DeviceState *dev, Error **errp)
  30 {
  31     M41t80State *s = M41T80(dev);
  32
  33     s->addr = -1;
  34 }
  35
  36 static int m41t80_send(I2CSlave *i2c, uint8_t data)
  37 {
  38     M41t80State *s = M41T80(i2c);
  39
  40     if (s->addr < 0) {
  41         s->addr = data;
  42     } else {
  43         s->addr++;
  44     }
  45     return 0;
  46 }
  47
  48 static uint8_t m41t80_recv(I2CSlave *i2c)
  49 {
  50     M41t80State *s = M41T80(i2c);
  51     struct tm now;
  52     qemu_timeval tv;
  53
  54     if (s->addr < 0) {
  55         s->addr = 0;
  56     }
  57     if (s->addr >= 1 && s->addr <= 7) {
  58         qemu_get_timedate(&now, -1);
  59     }
  60     switch (s->addr++) {
  61     case 0:
  62         qemu_gettimeofday(&tv);
  63         return to_bcd(tv.tv_usec / 10000);
  64     case 1:
  65         return to_bcd(now.tm_sec);
  66     case 2:
  67         return to_bcd(now.tm_min);
  68     case 3:
  69         return to_bcd(now.tm_hour);
  70     case 4:
  71         return to_bcd(now.tm_wday);
  72     case 5:
  73         return to_bcd(now.tm_mday);
  74     case 6:
  75         return to_bcd(now.tm_mon + 1);
  76     case 7:
  77         return to_bcd(now.tm_year % 100);
  78     case 8 ... 19:
  79         qemu_log_mask(LOG_UNIMP, "%s: unimplemented register: %d\n",
  80                       __func__, s->addr - 1);
  81         return 0;
  82     default:
  83         qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid register: %d\n",
  84                       __func__, s->addr - 1);
  85         return 0;
  86     }
  87 }
  88
  89 static int m41t80_event(I2CSlave *i2c, enum i2c_event event)
  90 {
  91     M41t80State *s = M41T80(i2c);
  92
  93     if (event == I2C_START_SEND) {
  94         s->addr = -1;
  95     }
  96     return 0;
  97 }
  98
  99 static void m41t80_class_init(ObjectClass *klass, void *data)
 100 {
 101     DeviceClass *dc = DEVICE_CLASS(klass);
 102     I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
 103
 104     dc->realize = m41t80_realize;
 105     sc->send = m41t80_send;
 106     sc->recv = m41t80_recv;
 107     sc->event = m41t80_event;
 108 }
 109
 110 static const TypeInfo m41t80_info = {
 111     .name          = TYPE_M41T80,
 112     .parent        = TYPE_I2C_SLAVE,
 113     .instance_size = sizeof(M41t80State),
 114     .class_init    = m41t80_class_init,
 115 };
 116
 117 static void m41t80_register_types(void)
 118 {
 119     type_register_static(&m41t80_info);
 120 }
 121
 122 type_init(m41t80_register_types)